Threshold concepts encountered by second year medical students in a Basic Health Science module; a qualitative study

Objective: To explore threshold concepts in a Basic Health Sciences module. Method: The qualitative study was conducted at the Islamabad Medical and Dental College, Islamabad, Pakistan, in March 2019, and comprised students and faculty members in the gastrointestinal tract module of spiral I of the integrated modular curriculum in Basic Health Sciences. Data on student experiences was collected using semi-structured interviews with open-ended questions.  The data was coded and themes were identified by the researchers independently.  A thematic matrix was produced, cross-referencing data relating to troublesome areas identified by the students against the threshold concept criteria. The identified themes were discussed among the researchers to reach consensus.  Only the identified themes were taken as the expected threshold concepts in the gastrointestinal tract module. Results: Of the 18 subjects, 14(77.8%) were students and 4(22.2%) were facilitators. There were 8 areas identified by the students as troublesome in the module; development of gastrointestinal tract, anatomical relations, electron transport chain, histology of gastrointestinal tract mucosa, peritoneal disposition, anal canal and ischioanal fossae, peristalsis, and absorption across gastrointestinal tract mucosa. Only development of gastrointestinal tract appeared to cross-match with all the criteria outlined for threshold concepts. The troublesome areas identified by the teachers were development of gastrointestinal tract, peritoneal disposition, anatomical relations, absorption across gastrointestinal tract and peristalsis. Conclusion: Development of gastrointestinal tractwas found to be the threshold concept in the system-based integrated module of gastrointestinal tract. Most of the students found their previous knowledge inadequate in learning concepts of the module.

Anesthesia for left ventricular assisted device insertion in a patient with multiple organ failure

Technological advances in mechanical circulatory support have enabled more patients with end-stage heart failure to benefit from left ventricular assist devices (LVAD). Indications for LVAD implantation have evolved to include patients who are deemed unsuitable for cardiac transplantation, otherwise known as destination therapy. This case report describes such patient with multi-organ failure who underwent LVAD insertion after nine days of extra-corporeal membrane oxygenation, intra-aortic balloon pump and maximal inotropic support. Strategies for perioperative management, as well as intra-operative monitoring and interventions are discussed.

Access-Site Complications in Mechanical Thrombectomy for Acute Ischemic Stroke: A Review of Prospective Trials

BACKGROUND

A shift has occurred in interventional cardiology from transfemoral to transradial access due to a 70%-80% decrease in complications. This shift has not yet taken place in other interventional specialties, perhaps owing to the lack of generalizability of findings in the cardiology data.

PURPOSE

Our aim was to assess data from the recent mechanical thrombectomy prospective trials to better understand the access-site complication rate.

DATA SOURCES

Articles were systematically sourced from the National Center for Biotechnology Information PubMed archive.

STUDY SELECTION

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, prospective, randomized controlled trials published after 2008 with mention of major and/or minor femoral access-site complications in neuroendovascular mechanical thrombectomies were included.

DATA ANALYSIS

Major and minor femoral access-site complications were extracted. A total complication rate was calculated with major access-site complications alone and combined with minor access-site complications.

DATA SYNTHESIS

Seven prospective studies of 339 total screened met the inclusion criteria. Eleven major access-site complications were identified in of 660 total interventions, revealing a major access-site complication rate of 1.67% for patients undergoing mechanical thrombectomy with transfemoral access. If minor access-site complications were included, 35 total incidents were detected in 763 interventions, resulting in a total complication rate of 4.59%.

LIMITATIONS

Multiple unspecified vessel and procedure-related complications were mentioned in the studies.

CONCLUSIONS

The overall rate of major access-site complications was 1.67% in this review, which is not low and poses a risk to patients. We suggest further investigation into the feasibility and complication rates of alternative access sites for neurointerventional procedures.

SPOP regulates prostate epithelial cell proliferation and promotes ubiquitination and turnover of c-MYC oncoprotein

The E3 ubiquitin ligase adaptor speckle-type POZ protein (SPOP) is frequently dysregulated in prostate adenocarcinoma (PC), via either somatic mutations or mRNA downregulation, suggesting an important tumor suppressor function. To examine its physiologic role in the prostate epithelium in vivo, we generated mice with prostate-specific biallelic ablation of Spop. These mice exhibited increased prostate mass, prostate epithelial cell proliferation, and expression of c-MYC protein compared to littermate controls, and eventually developed prostatic intraepithelial neoplasia (PIN). We found that SPOP^WT can physically interact with c-MYC protein and, upon exogenous expression in vitro, can promote c-MYC ubiquitination and degradation. This effect was attenuated in PC cells by introducing PC-associated SPOP mutants or upon knockdown of SPOP via short-hairpin-RNA, suggesting that SPOP inactivation directly increases c-MYC protein levels. Gene set enrichment analysis revealed enrichment of Myc-induced genes in transcriptomic signatures associated with SPOP^MT. Likewise, we observed strong inverse correlation between c-MYC activity and SPOP mRNA levels in two independent PC patient cohorts. The core SPOP^MT;MYC^High transcriptomic response, defined by the overlap between the SPOP^MT and c-MYC transcriptomic programs, was also associated with inferior clinical outcome in human PCs. Finally, the organoid-forming capacity of Spop-null murine prostate cells was more sensitive to c-MYC inhibition than that of Spop-WT cells, suggesting that c-MYC upregulation functionally contributes to the proliferative phenotype of Spop knock-out prostates. Taken together, our data highlight SPOP as an important regulator of luminal epithelial cell proliferation and c-MYC expression in prostate physiology, identify c-MYC as a novel bona fide SPOP substrate, and help explain the frequent inactivation of SPOP in human PC. We propose SPOP^MT–induced stabilization of c-MYC protein as a novel mechanism that can increase total c-MYC levels in PC cells, in addition to amplification of c-MYC locus.

Genotypic resistance testing in HIV-infected pregnant women in an urban setting

This study examines the utility of HIV genotypic resistance testing (GT) in pregnant women at their initial pregnancy evaluation. A retrospective medical record review of 50 consecutive HIV-infected pregnant women in whom GT was obtained in the Bronx, New York was conducted. Twenty-eight (56%) were antiretroviral experienced, including 12 on antiretroviral therapy (ART) at time of GT. Major mutations were found in 11 (24%) of 45 amplifiable GTs. Major resistance mutations were identified against nucleoside reverse transcriptase inhibitors (NRTIs) in six (13%) patients; against non-nucleoside reverse transcriptase inhibitors (NNRTIs) in eight (18%) patients, and against protease inhibitors in two (4%) patients. Duration of ART exposure was significantly associated with identification of resistance mutations by GT for NRTIs and NNRTIs ( P ≥0.05). Results of this study indicate that GT at presentation may have implications on the initial choice of ART in up to one-quarter of HIV-infected pregnant women, especially with current or prior antiretroviral use.

Duration effect of Acacia nilotica leaves extract and glibenclamide as hypolipidaemic and hypoglycaemic activity in alloxan induced diabetic rats

OBJECTIVE

To compare the duration and effects of aqueous methanol Acacia-nilotica leaves extract and glibenclamide as hypoglycaemic and hypolipidaemic activity in diabetic rats.

METHODS

The experimental study was conducted at Shifa International Hospital in collaboration with National Institute of Health, Islamabad, from September 2010 to August 2011.Male Sprague Dawley albino rats were taken and divided into 8 equal groups. Groups I and II were the normal and diabetic control rats. Diabetes mellitus was induced in group II to VIII by administering 110 mg/kg body weight alloxanand at day 4, fasting blood glucose level of >200 mg/dl confirmed diabetes. Acacia-nilotica leaves extract was given to group III, IV and V and glibenclamide to group VI to VIII for a period of 1-3 weeks. Blood samples were analysed for lipid profile using enzymatic calorimetric method and serum insulin by enzyme-linked immunosorbent assay on days 0, 7, 14, and 21.

RESULTS

There were 64 rats in the study, with 8(12.5%) in each group. Statistically significant decreases in fasting blood glucose, total cholesterol, triglyceride, phospholipids, low density lipoprotein, very low density lipoprotein and an increase in high density lipoprotein and serum insulin levels were observed in diabetic rats compared to diabetic controls after 2 weeks of treatment with plant extract and glibenclamide (p<0.05 each).When plant extract and drug treated diabetic rats were compared, a significant difference in the levels of blood glucose, insulin, total cholesterol and triglyceride levels were noted after 2 and 3 weeks of treatment.

CONCLUSIONS

Acacia-nilotica leaves extract resulted in hypoglycaemic and hypolipidaemic effect in alloxan-induced diabetic rats similar to glibenclamide.

Comprehensive proteomic profiling identifies the androgen receptor axis and other signaling pathways as targets of microRNAs suppressed in metastatic prostate cancer

MicroRNAs are important epigenetic regulators of protein expression by triggering degradation of target mRNAs and/or inhibiting their translation. Dysregulation of microRNA expression has been reported in several cancers, including prostate cancer (PC). We comprehensively characterized the proteomic footprint of a panel of 12 microRNAs that are potently suppressed in metastatic PC (SiM-miRNAs: miR-1, miR-133a, miR-133b, miR-135a, miR-143-3p, miR-145-3p, miR-205, miR-221-3p, miR-221-5p, miR-222-3p, miR-24-1-5p, and miR-31) using reverse-phase proteomic arrays. Re-expression of these SiM-miRNAs in PC cells suppressed cell proliferation and targeted key oncogenic pathways, including cell cycle, apoptosis, Akt/mammalian target of rapamycin signaling, metastasis and the androgen receptor (AR) axis. However, only 12%, at most, of these observed protein expression changes could be explained by predicted direct binding of miRNAs to corresponding mRNAs, suggesting that the majority of these proteomic effects result indirectly. AR and its steroid receptor coactivators (SRCs; SRC-1, -2 and -3) were recurrently affected by these SiM-miRNAs. In agreement, we identified inverse correlations between expression of these SiM-miRNAs and early clinical recurrence, as well as with AR transcriptional activity in human PC tissues. We also identified robust induction of miR-135a by androgen and strong direct binding of AR to the miR-135a locus. As miR-135a potently suppresses AR expression, this results in a negative feedback loop that suppresses AR protein expression in an androgen-dependent manner, while de-repressing AR expression upon androgen deprivation. Our results demonstrate that epigenetic silencing of these SiM-miRNAs can result in increased AR axis activity and cell proliferation, thus contributing to disease progression. We further demonstrate that a negative feedback loop involving miR-135a can restore AR expression under androgen-deprivation conditions, thus contributing to the upregulation of AR protein expression in castration-resistant PC. Finally, our unbiased proteomic profiling demonstrates that the majority of actual protein expression changes induced by SiM-miRNAs cannot be explained based on predicted direct interactions.

Monoamine Oxidase A gene polymorphisms and self reported aggressive behaviour in a Pakistani ethnic group

OBJECTIVE

To investigate the association of monoamine oxidase Agene polymorphisms with aggression.

METHODS

The study was conducted in an ethnic community in Lahore, Pakistan, from August 2008 to December 2009 on the basis of data that was collected through a questionnaire between August 2004 and September 2005. It analysed 10 single nucleotide polymorphisms of monoamine oxidase A in unrelated males from the same ethnic background who were administered a Punjabi translation of the Buss and Perry aggression questionnaire. SPSS 13 was used for statistical analysis.

RESULTS

Of the total 133 haplotypes studied, 52(39%) were Haplotype A, 58(43.6%) B, 8(6%) C, 3(2.3%) D, 9(6.8%) E and 3(2.3%) F. The six haplotypes were analysed for association with scores of the four subscales of the aggression questionnaire and multivariate analysis of variance showed no significant differences (p>0.05 each) in the error variances of the total scores and scores for three of the sub-scales across the haplotypes. The variance was significantly different only for the anger sub-scale (p<0.05).

CONCLUSIONS

The association of an extended haplotype with low levels of self-reported aggression in this study should assist in characterisation of functional variants responsible for non-aggressive behaviour in male subjects.

Abstract P6-04-03: ERb and breast cancer: A potential predictive and prognostic biomarker and novel therapeutic drug target

Background: Estrogen receptor beta (ERβ), unlike ERα, classically functions as a tumor suppressor in vitro. However, ERβ's biological functions in vivo and predictive/prognostic value in breast cancer are controversial.

Methods: Expression of ERβ protein was determined using a well characterized and validated ERβ specific monoclonal antibody that only recognizes the full-length form of this receptor (PPG5/10) in the following 3 cohorts: 1) a cohort with all breast cancer subtypes (n = 182), 2) a prospective NCCTG adjuvant tamoxifen trial for postmenopausal women with ERα positive breast cancer with long-term follow-up (n = 198) and 3) a cohort of 80 triple negative breast cancers (TNBCs). To elucidate the biological functions of ERβ in breast cancer, novel ERβ expressing MCF7 and MDA-MB-231 cell lines were developed and characterized using multiple techniques and were examined for responsiveness to various ERβ targeted therapies.

Results: About one-third of all breast tumors, regardless of sub-type, were shown to express nuclear ERβ and this expression was independent of ERα or HER2. In the NCCTG 89-30-52 cohort, breast cancer recurrence rates were significantly associated with ERβ protein expression with 10 year recurrence rates of 25%, 15% and 4% for zero, low or high levels of ERβ expression respectively. Interestingly, in TNBCs, nuclear ERβ was expressed at intermediate or high levels in 24% of tumors. In the triple negative MDA-MB-231 cell line, expression of ERβ led to inhibition of proliferation and induction of apoptosis in response to estrogen and multiple ERβ specific agonists. Conversely, these same treatments induced proliferation of ERβ-expressing MCF7 cells which endogenously express ERα. However, ERβ expression sensitized MCF7 cells to the anti-proliferative effects of anti-estrogens. Microarray analysis and RT-PCR profiling of MDA-MB-231-ERβ cells revealed that estrogen and ERβ agonists highly induced the expression of multiple cystatins, a family of small secreted cysteine protease inhibitors which function as tumor suppressors, and potently inhibited canonical TGFβ signaling. Conditioned media isolated from estrogen or ERβ agonist treated MDA-MB-231-ERβ cells suppressed the proliferation rates and inhibited TGFβ signaling in other TNBC cell lines, effects that were completely reversed following the depletion of cystatins from the conditioned media.

Conclusions: These data demonstrate that ERβ is expressed in a substantial proportion of breast cancers and may have value as a predictive and/or prognostic biomarker. Therapeutic targeting of ERβ may have clinical benefit in multiple breast cancer sub-types; however, the specific drug of choice may vary based on ERα status. Specifically, we have demonstrated that ERβ expression in ERα+ MCF7 cells sensitizes them to the effectiveness of anti-estrogens, an observation that was confirmed in women enrolled in a prospective adjuvant tamoxifen trial. In TNBCs, where targeted therapies are lacking, our data suggest that targeting ERβ with either estrogen or ERβ specific agonists will elicit anti-tumor effects through the induction of cystatins and inhibition of TGFβ signaling resulting in tumor regression and improved patient outcomes.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-04-03.

Emergency contraception: knowledge, attitude and practices among doctors of a tertiary care hospital

BACKGROUND

In Pakistan maternal mortality rate (MMR) is very high and more than one in five women die from pregnancy related causes; solution to this is to have low fertility rate. The emergency contraceptives (ECs) can be used to prevent unwanted pregnancies. The aim of this study was to assess the knowledge, attitude and practice about ECs among doctors.

METHODS

Institution-based cross-sectional descriptive study on knowledge, attitude and practice of ECs was conducted at Rawal Hospital from Feb to May, 2012. Data was collected using structured questionnaire and analysed using SPSS-16.

RESULTS

Fifty-seven percent of the respondents were > 30 years of age, 94% were Muslim, 81% were married and 51% were women. Ninety-seven percent had heard of ECs before, only 17% knew Intra-uterine contraceptive device (IUCD) a method of EC. Sixty-one percent responded that IUCD should be removed if patient gets pregnant (p = 0.007) and according to 31% ECs were not abortifacient (p = 0.045). Regarding attitude, 55.5% of the participants supported its use (p = 0.027) and agreed to its easy accessibility (p = 0.004). Thirty-eight percent responded an increased dose of birth control pills as a form of EC (p = 0.008), while 40% did not agree that ECs are effective when taken before intercourse (p = 0.011).

CONCLUSION

Knowledge and practice of ECs is very low among doctors but a positive attitude is there. Evidence-based knowledge to family physicians regarding emergency contraception is strongly recommended to reduce the chances of MMR.

CSF opening pressure in children with optic nerve head edema

BACKGROUND

We previously reported that an abnormal CSF opening pressure (OP) in children was greater than 28 cm H(2)O. Since elevated intracranial pressure can cause optic nerve head edema (ONHE), we would expect that most patients with ONHE would have an OP greater than 28 cm H(2)O. This study describes the range of OP for children with ONHE and compared them to age-matched controls without ONHE.

METHODS

Case subjects were children (1-18 years of age) enrolled in a prospective study of CSF OP that demonstrated ONHE at time of lumbar puncture and that the ONHE later resolved. Patients with ONHE secondary to infectious, inflammatory, or ischemic conditions were excluded. Control subjects from the same study, but without ONHE, were matched to cases.

RESULTS

Of the 472 subjects enrolled in the study, 41 OP measurements were obtained from 33 patients with ONHE who did not have any exclusionary criteria and matched to 41 control subjects without ONHE. Case subjects had a significantly higher OP (mean, 41.4 cm H(2)0; range, 22-56) than control subjects (mean, 18.9 cm H(2)O; range, 9-29; p < 0.01). Forty of 41 (97.6%) case subjects and 2 of 41 (4.8%) control subjects had OP measures >28 cm H(2)O.

CONCLUSIONS

Children with ONHE not related to infectious, inflammatory, or ischemic causes typically have an OP >28 cm H(2)O, significantly higher than age-matched controls without ONHE. This study provides further support to our previously published findings that suggests an abnormal OP in children is typically above 28 cm H(2)O.

Antazoline in the treatment of cardiac arrhythmias

Antazoline was administered in sixty-five episodes of various types of cardiac arrhythmia. A complete suppression of the ectopic beats was achieved in five out of six episodes of premature atrial systoles and in twenty-one of the twenty-four episodes of ventricular premature systoles. Conversion to sinus rhythm was observed in seven out of ten and four out of five episodes of paroxysmal atrial and nodal tachycardia respectively. Six out of ten episodes of ventricular tachycardia were controlled by intravenous therapy. However, the drug proved to be ineffective in cases of atrial fibrillation. The side-effects were few and transitory, consisting of nausea, vomiting and drowsiness.

Inhaled versus systemic corticosteroids for the treatment of chronic lung disease in ventilated very low birth weight preterm infants

BACKGROUND

Chronic lung disease (CLD) remains a serious and common problem among very low birth weight infants despite the use of antenatal steroids and postnatal surfactant therapy to decrease the incidence and severity of respiratory distress syndrome. Due to their anti-inflammatory properties, corticosteroids have been widely used to treat or prevent CLD. However, the use of systemic steroids has been associated with serious short and long-term adverse effects. Administration of corticosteroids topically through the respiratory tract might result in beneficial effects on the pulmonary system with fewer undesirable systemic side effects.

OBJECTIVES

To determine the effect of inhaled versus systemic corticosteroids administered to ventilator dependent preterm neonates with birth weight < 1500 g or gestational age < 32 weeks after two weeks of life for the treatment of evolving CLD.

SEARCH STRATEGY

Randomized and quasi-randomized trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2007), MEDLINE (1966 - June 2007), EMBASE (1980 - June 2007), CINAHL (1982 - June 2007), reference lists of published trials and abstracts published in Pediatric Research or electronically on the Pediatric Academic Societies website (1990 - April 2007).

SELECTION CRITERIA

Randomized or quasi-randomized trials comparing inhaled versus systemic corticosteroid therapy (irrespective of the dose and duration of therapy) starting after the first two weeks of life in ventilator dependent very low birth weight preterm infants.

DATA COLLECTION AND ANALYSIS

Data were extracted regarding clinical outcomes including CLD at 28 days or 36 weeks postmenstrual age (PMA), mortality, combined outcome of death or CLD at 28 days of age or 36 weeks PMA, other pulmonary outcomes and adverse effects. All data were analyzed using RevMan 4.2.10. When appropriate, meta-analysis was performed using relative risk (RR), risk difference (RD), and weighted mean difference (WMD) along with their 95% confidence intervals (CI). If RD was statistically significant, the number needed to treat (NNT) was calculated.

MAIN RESULTS

Data from one additional trial were available for inclusion in this update. Thus, five trials comparing inhaled versus systemic corticosteroids in the treatment of CLD were identified. Two trials were excluded as both included non-ventilator dependent patients and three trials qualified for inclusion in this review. Halliday et al (Halliday 2001) randomized infants at < 72 hours, while Rozycki et al (Rozycki 2003) and Suchomski et al (Suchomski 2002) randomized at 12 - 21 days. The data from the two trials of Rozycki et al and Suchmoski et al are combined using meta-analytic techniques. The data from the trial by Halliday et al are reported separately, as outcomes were measured over different time periods from the age at randomization. In none of the trials was there a statistically significant difference between the groups in the incidence of CLD at 36 weeks PMA among all randomized infants. The estimates for the trial by Halliday et al (Halliday 2001) were RR 1.10 (95% CI 0.82, 1.47), RD 0.03 (95% CI -0.08, 0.15); number of infants (n = 292). For the trials by Rozycki et al (Rozycki 2003) and Suchomski et al (Suchomski 2002) the typical RR was 1.02 (95% CI 0.83, 1.25) and the typical RD 0.01 (95% CI -0.11, 0.14); (number of infants = 139 ). There were no statistically significant differences between the groups in either trial for oxygen dependency at 28 days of age, death by 28 days or 36 weeks PMA, the combined outcome of death by or CLD at 28 days or 36 weeks PMA, duration of intubation, duration of oxygen dependence, or adverse effects. Information on the long-term neurodevelopmental outcomes was not available.

AUTHORS' CONCLUSIONS

This review found no evidence that inhaled corticosteroids confer net advantages over systemic corticosteroids in the management of ventilator dependent preterm infants. Neither inhaled steroids nor systemic steroids can be recommended as standard treatment for ventilated preterm infants. There was no evidence of difference in effectiveness or side-effect profiles for inhaled versus systemic steroids. A better delivery system guaranteeing selective delivery of inhaled steroids to the alveoli might result in beneficial clinical effects without increasing side-effects. To resolve this issue, studies are needed to identify the risk/benefit ratio of different delivery techniques and dosing schedules for the administration of these medications. The long-term effects of inhaled steroids, with particular attention to neurodevelopmental outcome, should be addressed in future studies.

Characterization of cytochrome P450-mediated drug metabolism in cats

In this study we examined activities of cytochrome P450 (CYP)1A, 2C, 2D and 3A using hepatic microsomes from five male and five female cats. CYP1A, 2C, 2D and 3A activities were referred by ethoxyresorufin O-deethylation (EROD), tolbutamide hydroxylation (TBH), bufuralol 1'-hydroxylation (BLH) and midazolam 1'- and 4-hydroxylation respectively. The anti-rat CYP1A2 and CYP3A2 serum significantly inhibited EROD and midazolam 1'- and 4-hydroxylation, suggesting that EROD and midazolam 1'- and 4-hydroxylation were catalysed by CYP1A and 3A in cats respectively. Quinidine inhibited BLH in cats microsomes at quite low concentrations, suggesting that BLH was catalysed by CYP2D in cats. Tolbutamide hydroxylation activities were negligible in hepatic microsomes from both male and female cats, suggesting CYP2C activities of cats are extremely low. This suggests that CYP2C substrates should be carefully administered to cats. Although there is no sexual difference in CYP1A activities, there are differences in CYP2D and 3A activities of cats. CYP2D activities were higher (3-fold), but CYP3A activities were lower (one-fifth) in female cats. These results might suggest that CYP2D and 3A substrates should be prescribed for male and female cats using different dosage regimen.

Renal Vein Thrombosis

OBJECTIVE

The aim of this article is to review the published English literature on aetiology, pathology, clinical presentation, diagnostic methods and treatment of renal vein thrombosis.

MATERIALS AND METHODS

We searched the published literature from Medline & Pubmed using keywords renal vein thrombosis, anti-phospholipid syndrome and nephrotic syndrome. Data was extracted from individual case reports, case series, articles on pathology, diagnostic tests, treatment modalities, and previous reviews. Case reports which did not add any new information were excluded.

RESULTS

We selected 60 references based on the above criteria. Renal vein thrombosis is relatively rare. CT angiography is considered the investigation of choice. Alternatives include MR angiography or renal venography in highly selected patients. As the condition is relatively uncommon, consensus on the best form of therapy for this condition has been slow to evolve. The trend in management has shifted to non-surgical therapies particularly systemic anticoagulation except in highly selected group of patients.

Lack of inhibitory effects of several fluoroquinolones on cytochrome P-450 3A activities at clinical dosage in dogs

Inhibitory effects of several fluoroquinolones (FQs) on liver CYP3A activities were examined by in vitro and in vivo tests in dogs. Midazolam (MDZ) hydroxylation rate was used to determine the CYP3A activities in liver microsomes. Enrofloxacin (EFX), ofloxacin (OFX) orbifloxacin (OBFX) and ciprofloxacin (CFX) were tested. None of the FQs changed Vmax, Km or intrinsic clearance (Vmax/Km) of MDZ. For in vivo test, we examined the effects of oral administration of EFX and OFX on the pharmacokinetics of quinidine (QN), a CYP3A substrate. EFX or OFX (10 mg/kg) was administered once a day for 3 days. QN (2 mg/kg) was intravenously injected at 2 h after the final dose of FQs administration. The same dose of QN was intravenously injected 3 weeks before the start of FQs administration for control. Neither EFX nor OFX changed the pharmacokinetic parameters of QN. These in vitro and in vivo consisted results suggest that these FQs lack the inhibitory effects on CYP3A activities in dogs. Hence, given these results, the risk of drug-drug interaction is unlikely to occur between FQs and CYP3A substrates in clinical situation in dogs.

Sorption of lead from aqueous solution by chemically modified carbon adsorbents

An indigenously prepared, steam activated and chemically modified carbon from husk and pods of Moringa oleifera (M. oleifera), an agricultural waste, was comparatively examined as an adsorbent for the removal of lead from aqueous solutions. Studies were conducted as a function of contact time, initial metal concentration, dose of adsorbent, agitation speed, particle size and pH. Maximum uptake capacities were found to be, 98.89, 96.58, 91.8, 88.63, 79.43% for cetyltrimethyl ammonium bromide (CTAB), phosphoric, sulfuric, hydrochloric acid treated and untreated carbon adsorbents, respectively. Bangham, pseudo-first- and second-order, intra-particle diffusion equations were implemented to express the sorption mechanism by utilized adsorbents. Adsorption rate of lead ions was found to be considerably faster for chemically modified adsorbents than unmodified. The results of adsorption were fitted to both the Langmuir and Freundlich models. Satisfactory agreement between the metal uptake capacities by the adsorbents at different time intervals was expressed by the correlation coefficient (R(2)). The Langmuir model represented the sorption process better than the Freundlich one, with R(2) values ranging from 0.994 to 0.998.

Upregulated TRPC1 channel in vascular injury in vivo and its role in human neointimal hyperplasia

Occlusive vascular disease is a widespread abnormality leading to lethal or debilitating outcomes such as myocardial infarction and stroke. It is part of atherosclerosis and is evoked by clinical procedures including angioplasty and grafting of saphenous vein in bypass surgery. A causative factor is the switch in smooth muscle cells to an invasive and proliferative mode, leading to neointimal hyperplasia. Here we reveal the importance to this process of TRPC1, a homolog of Drosophila transient receptor potential. Using 2 different in vivo models of vascular injury in rodents we show hyperplasic smooth muscle cells have upregulated TRPC1 associated with enhanced calcium entry and cell cycle activity. Neointimal smooth muscle cells after balloon angioplasty of pig coronary artery also express TRPC1. Furthermore, human vein samples obtained during coronary artery bypass graft surgery commonly exhibit an intimal structure containing smooth muscle cells that expressed more TRPC1 than the medial layer cells. Veins were organ cultured to allow growth of neointimal smooth muscle cells over a 2-week period. To explore the functional relevance of TRPC1, we used a specific E3-targeted antibody to TRPC1 and chemical blocker 2-aminoethoxydiphenyl borate. Both agents significantly reduced neointimal growth in human vein, as well as calcium entry and proliferation of smooth muscle cells in culture. The data suggest upregulated TRPC1 is a general feature of smooth muscle cells in occlusive vascular disease and that TRPC1 inhibitors have potential as protective agents against human vascular failure.

Ibuprofen for the prevention of patent ductus arteriosus in preterm and/or low birth weight infants

BACKGROUND

A patent ductus arteriosus (PDA) often complicates the clinical course of preterm infants and increases the risk of intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), chronic lung disease (CLD) and death. The standard treatment to close a PDA is indomethacin. Its use is associated with renal, gastrointestinal and cerebral side-effects. Ibuprofen has been shown to be effective in closing a PDA without reducing blood flow velocity to the brain, gut or kidneys.

OBJECTIVES

To determine the effectiveness and safety of prophylactic ibuprofen compared to placebo/no intervention or other cyclo-oxygenase inhibitor drugs (indomethacin, mefenamic acid, etc) in the prevention of PDA in preterm infants.

SEARCH STRATEGY

Randomized controlled trials comparing prophylactic ibuprofen use with placebo/no intervention/indomethacin were identified by searching the Cochrane Central Register of Controlled Trial (CENTRAL, The Cochrane Library, Issue 3, 2005), MEDLINE (1966-July 2005), CINAHL (1982-July 2005), EMBASE (1980-July 2005), reference lists of published trials and abstracts published in Pediatric Research (1990-July 2005). No language restrictions were applied.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials comparing use of ibuprofen with placebo/no intervention or other cyclo-oxygenase inhibitor drugs (indomethacin, mefenamic acid, etc) for the prevention of PDA in preterm and/or low birth weight infants.

DATA COLLECTION AND ANALYSIS

Data regarding the clinical outcomes including presence of PDA on day three and day seven, need for surgical ligation, need for rescue treatment with cyclo-oxygenase inhibitors, IVH, mortality, renal and gastrointestinal complications were extracted. Meta-analyses were performed using RevMan 4.2 and treatment estimates were reported as weighted mean difference (WMD), typical relative risk (RR), typical risk difference (RD) and, if statistically significant, number needed to treat (NNT) or number needed to harm (NNH), along with their 95% confidence intervals (CI).

MAIN RESULTS

Four trials (n = 672) were included in the review. There was a statistically significant decrease in the incidence of PDA on day three in the ibuprofen group [typical RR 0.37 (95% CI 0.29, 0.49); typical RD -0.29 (95% CI -0.35, -0.22); NNT 3 (95% CI 3, 5); 4 trials, n = 672], in the need for rescue treatment with cyclo-oxygenase inhibitors [typical RR 0.17 (95% CI 0.11, 0.27), typical RD -0.27 (95% CI -0.35, -0.22); NNT 4 (95%CI 3, 5), and in the need for surgical ligation [typical RR 0.34 (95% CI 0.14, 0.81), typical RD -0.04 (95% CI -0.07, -0.01); NNT 25 (95% CI 14, 100). The PDA had closed spontaneously by day three in 60% of the neonates in the control group. There was a significant increase in the serum creatinine levels in the ibuprofen group [WMD 0.13 mg/dl (95% CI 0.08, 0.17); 2 trials, n = 495]. Ibuprofen reduces urine output. There were no statistically significant differences in mortality, grade 3/4 intraventricular hemorrhage, chronic lung disease at 28 days or 36 weeks, necrotizing enterocolitis , gastrointestinal hemorrhage, intestinal perforation or time to reach full feeds. One trial (Gournay 2002) (n = 135) reported on three infants in the ibuprofen group who developed pulmonary hypertension responsive to nitric oxide treatment.

AUTHORS' CONCLUSIONS

Prophylactic use of ibuprofen reduces the incidence of PDA, the need for rescue treatment with cyclo-oxygenase inhibitors and surgical closure. However, in the control group, the PDA had closed spontaneously by day three in 60% of the neonates. Prophylactic treatment therefore exposes a large proportion of infants unnecessarily to a drug that has important side effects (mainly involving the kidneys) without conferring any important short term benefits. Prophylactic treatment with ibuprofen is not recommended. Until long-term follow-up results are published from the trials included in this review, no further trials of prophylactic ibuprofen are recommended.

An imaging study of body composition including lipodeposition pattern in a patient of familial partial lipodystrophy (Dunnigan type)

Familial Partial Lipodystrophy, Dunnigan type (FPLD), is characterised by loss of subcutaneous fat from the limbs and an excessive accumulation of fat on the neck, shoulder girdle and face. Affected individuals have insulin resistance, dyslipidaemia and early cardiovascular events. Body composition (BC) with details of adipose tissue distribution were studied by Dual-Energy X-ray Absorptiometry (DEXA) and Magnetic Resonance Imaging (MRI) ina heterozygote for the FPLD mutation LMNA R482W, and in an age, sex and body mass index (BMI) matched normal control. DEXA revealed a marked decrease in total as well as regional fat percentage in the patient compared to a normal control. Marked reductions in subcutaneous fat in the extremities with substantial lipodeposition in the nape of the neck were confirmed with. MRI. The importance of increased perinephric, retroperitoneal and intermuscular fat in the thighs found in this patient, needs to be explored vis-à-vis the pathogenesis of insulin resistance found in FPLD.

Multiple versus single lumen umbilical venous catheters for newborn infants

BACKGROUND

Multiple lumen umbilical venous catheters (ML-UVCs) instead of single lumen UVCs (SL-UVCs) may decrease the need for additional venous lines. Although it seems self-evident that ML-UVCs would reduce the need of additional venous lines, the rates of associated complications might be different.

OBJECTIVES

To compare the effectiveness and the safety of ML-UVCs versus SL-UVCs in terms of need of additional vascular access, rates of complications, morbidity and mortality in newborn infants.

SEARCH STRATEGY

Randomized and quasi-randomized trials were identified by searching the MEDLINE (1966 - February 2005), EMBASE (1980- February 2005), CINAHL (1982 - February 2005), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2004) and Science Direct (subject area: medicine, journal and abstract database; 1967 to February 2005). Literature search also included a manual search of the abstracts of scientific meetings published in Pediatric Research (1990-2004). Additional citations were sought using references in articles retrieved from searches. Subject experts were contacted to identify the unpublished and ongoing studies.

SELECTION CRITERIA

Randomized and quasi-randomized controlled clinical trials comparing safety and efficacy of multiple versus single lumen umbilical venous catheter in neonates (both term and preterm) who were in need of umbilical venous catheter insertion for vascular access in first four weeks of life.

DATA COLLECTION AND ANALYSIS

Each review author performed data extraction independently and differences were resolved by discussion. The following outcomes were determined: total number of additional peripheral intravenous lines per baby in first week and first four weeks of life, total number of additional percutaneously and surgically placed central venous lines per baby in first four weeks of life, and other safety and efficacy measures. The treatment effect estimators used were RR, RD, and WMD when appropriate along with their 95% CI. If RD was statistically significant, then number needed to treat (NNT) or number needed to harm (NNH) was calculated.

MAIN RESULTS

Three studies qualified for inclusion in this review (Khilnani 1991; Loisel 1996; Soupre 1998). There was a decrease in the ML-UVCs group in the number of additional PIVs used in the first week of life [WMD -1.42, (95% CI -1.74, -1.10), p<0.00001, number of infants (n) = 99]. There was no significant effect on the number of additional PIVs used in the first four weeks of life [MD -2.30, (95% CI -6.65, 2.05), n=36]. There was an increase in catheter malfunction in the ML-UVCs group [typical RR 3.69 (95% CI 0.99, 13.81), p=0.05; RD 0.15 (95% CI 0.03, 0.27), p=0.01; NNH was 7, 95% CI 4, 33; n=99]. The following outcomes were not significantly different in the two groups: clinical sepsis, catheter related blood stream infection, catheter-associated thrombosis, complications related to catheter malposition in heart and great vessels, NEC and early neonatal mortality.

AUTHORS' CONCLUSIONS

The use of ML-UVCs in comparison to SL-UVCs in neonates is associated with decrease in the usage of PIVs in first week of life, but an increase in catheter malfunctions. As the quality of included randomized studies is poor and the estimates of clinically important complications are imprecise, no firm recommendations can be made regarding the choice of UVC. Adequately powered, properly randomized and properly blinded controlled trials are needed that address the effectiveness and safety of ML-UVCs (double and triple lumen) in comparison to SL-UVCs. These studies should also address the impact of type of catheter material.

Ibuprofen for the prevention of patent ductus arteriosus in preterm and/or low birth weight infants

BACKGROUND

A patent ductus arteriosus (PDA) often complicates the clinical course of preterm infants and increases the risk of intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), chronic lung disease (CLD) and death. The standard treatment to close a PDA is indomethacin. Its use is associated with renal, gastrointestinal and cerebral side-effects. Ibuprofen has been shown to be effective in closing a PDA without reducing blood flow velocity to the brain, gut or kidneys.

OBJECTIVES

To determine the effectiveness and safety of prophylactic ibuprofen compared to placebo/no intervention or other cyclo-oxygenase inhibitor drugs (indomethacin, mefenamic acid, etc) in the prevention of PDA in preterm infants.

SEARCH STRATEGY

Randomized controlled trials comparing prophylactic ibuprofen use with placebo/no intervention/indomethacin were identified by searching the Cochrane Controlled Trial Register (The Cochrane Library, Issue 4, 2002), MEDLINE (1966-November 2002), CINAHL (1982-November 2002), EMBASE (1980-November 2002), reference lists of published trials and abstracts published in Pediatric Research (1990-2002). No language restrictions were applied.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials comparing use of ibuprofen with placebo/no intervention or other cyclo-oxygenase inhibitor drugs (indomethacin, mefenamic acid, etc) for the prevention of PDA in preterm and/or low birth weight infants.

DATA COLLECTION AND ANALYSIS

Data regarding the clinical outcomes including presence of PDA on day three and day seven, need for surgical ligation, need for rescue treatment with cyclo-oxygenase inhibitors, IVH, mortality, renal and gastrointestinal complications were extracted. Meta-analyses were performed using RevMan 4.1 and treatment estimates were reported as weighted mean difference (WMD), typical relative risk (RR), typical risk difference (RD) and, if statistically significant, number needed to treat (NNT) or number needed to harm (NNH), along with their 95% confidence intervals (CI).

MAIN RESULTS

Four trials (n = 623) were included in the review. There was a statistically significant decrease in the incidence of PDA on day three in the ibuprofen group [typical RR 0.36 (95% CI 0.26, 0.49); typical RD -0.29 (95% CI -0.37, -0.21); NNT 3 (95% CI 3, 5); 3 trials, n = 488]. There was a significant increase in the serum creatinine levels in the ibuprofen group [WMD 0.11 mg/dl (95% CI 0.06, 0.17); 2 trials, n = 438]. There were no statistically significant differences in mortality, grade 3 or 4 IVH, CLD at 28 days or 36 weeks, need for surgical closure of PDA, NEC, GI hemorrhage, time to reach full feeds and urine output. One trial (Gournay 2002) (n = 135) reported on three infants in the ibuprofen group who developed pulmonary hypertension responsive to nitric oxide treatment.

REVIEWER'S CONCLUSIONS

Prophylactic use of ibuprofen reduces the incidence of PDA. However, further trials, which address potential adverse effects including pulmonary hypertension, are needed. Such trials should include long-term neurodevelopmental outcomes. Trials comparing the effectiveness of prophylactic use of indomethacin versus ibuprofen may be warranted with particular reference to IVH, need for surgical ligation and neurodevelopmental outcome.

Inhaled versus systemic corticosteroids for preventing chronic lung disease in ventilated very low birth weight preterm neonates

BACKGROUND

Chronic lung disease (CLD) remains an important cause of mortality and morbidity in preterm infants despite the administration of antenatal corticosteroids, surfactant replacement therapy and other advances in neonatal intensive care. There is increasing evidence from cellular and biochemical research that inflammation plays an important role in the pathogenesis of CLD. Thus, interventions aimed at reducing or modulating the inflammatory process may reduce the incidence or severity of CLD. Theoretically, the use of inhaled corticosteroids may allow for beneficial effects on the pulmonary system without concomitant high systemic concentrations and less risk of adverse effects.

OBJECTIVES

To compare the effectiveness of inhaled versus systemic corticosteroids, started within the first two weeks of life, in preventing CLD in ventilated very low birth weight infants.

SEARCH STRATEGY

Randomized and quasi-randomized trials were identified by searching the Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 2002), MEDLINE (1966 - September 2002), EMBASE (1980 - September 2002), CINAHL (1982 - September 2002), reference lists of published trials and abstracts published in Pediatric Research (1990 - April 2002) from the Society of Pediatric Research/ Pediatric Academic Society's annual meetings.

SELECTION CRITERIA

Randomized or quasi-randomized clinical trials comparing inhaled versus systemic corticosteroid therapy (regardless of the dose and duration of therapy), started in first two weeks of life in very low birth weight preterm infants receiving assisted ventilation.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including CLD at 28 days or 36 weeks corrected gestational age (CGA), mortality, combined outcome of death or CLD at 28 days or 36 weeks CGA, other pulmonary outcomes and adverse effects were evaluated. All data were analyzed using RevMan 4.1. When appropriate, meta-analysis was performed using relative risk (RR), risk difference (RD), and weighted mean difference (WMD) along with their 95% confidence intervals (CI). If RD was significant, number needed to treat (NNT) or number needed to harm (NNH) was calculated.

MAIN RESULTS

Two trials qualified for inclusion in this review. There was an increase in the incidence of CLD at 36 weeks CGA in the inhaled steroid group amongst all randomized infants, which was of borderline statistical significance: [RR 1.45 (95% CI 0.99, 2.11); RD 0.11 (95% CI 0.00, 0.21), p = 0.05, 1 trial and n = 278]. There was no statistically significant difference in the incidence of CLD at 36 weeks amongst all survivors [RR 1.34 (95% CI 0.94, 1.90); RD 0.11(95% CI -0.02, 0.24), 1 trial and n = 206]. There were no statistically significant differences for oxygen dependency at 28 days (2 trials and n = 294), death by 28 days (2 trials and n = 294) or 36 weeks (2 trials and n = 294) and the combined outcome of death or CLD by 28 days (2 trials and n = 294) or 36 weeks CGA (1 trial and n = 278). The duration of mechanical ventilation was statistically significantly longer in the inhaled as compared to the systemic steroid group (WMD 3.89 days, 95% CI 0.24, 7.55; 2 trials and n = 294). The duration of supplemental oxygen was statistically significantly longer in the inhaled as compared to the systemic steroid group (WMD 11.10 days, 95% CI 1.97, 20.22; 2 trials and n = 294). There was a significantly lower incidence of hyperglycemia in the group receiving inhaled steroids (RR 0.52, 95% CI 0.39,0.71; RD -0.25, 95% CI -0.37, -0.14; 1 trial and n = 278). The NNT was 4.0 (95% CI 2.7, 7.14) to avoid one infant experiencing hyperglycemia. There was a statistically significant increase in the rate of patent ductus arteriosus (RR 1.64, 95% CI 1.23, 2.17; RD 0.21, 95% CI 0.10, 0.33; 1 trial and n = 278) in the group receiving inhaled steroids. The NNH was 4.8, 95% CI 3, 10. There were decreases of borderline statistical significance in the incidences of gastrointestinal hemorrhage and gastrointestinal perforation in the inhaled as compared to systemic steroid group: for gastrointestinal hemorrhage, RR 0.40, 95% CI 0.16, 1.02; RD -0.06, 95% CI -0.12, 0.00, p = 0.05 (1 trial and n = 278); for gastrointestinal perforation, RR 0.16, 95% CI 0.02, 1.29; RD -0.04, 95% CI -0.07, 0.00, p = 0.05 (1 trial and n = 278). The incidence of other side effects was not statistically significantly different in the two groups. No information was available on long term neurodevelopmental outcomes.

REVIEWER'S CONCLUSIONS

This review found no evidence that early inhaled steroids confer important advantages over systemic steroids in the management of ventilator dependent preterm infants. Neither inhaled steroids, nor systemic steroids, can be recommended as a part of standard practice for ventilated preterm infants. Because they might have fewer adverse effects than systemic steroids, further randomized controlled trials of inhaled steroids are needed which address risk/benefit ratio of different delivery techniques, dosing schedules and long term effects, with particular attention to neurodevelopmental outcome.

Inhaled versus systemic corticosteroids for the treatment of chronic lung disease in ventilated very low birth weight preterm infants

BACKGROUND

Chronic lung disease (CLD) remains a serious and common problem among very low birth weight infants despite the use of antenatal steroids and postnatal surfactant therapy to decrease the incidence and severity of respiratory distress syndrome. Corticosteroids have been widely used to treat or prevent CLD due to their anti-inflammatory properties. However, the use of systemic steroids has been associated with serious short and long term adverse effects. Administration of corticosteroids topically through the respiratory tract might result in beneficial effects on the pulmonary system with fewer undesirable systemic side effects.

OBJECTIVES

To compare the effectiveness of inhaled versus systemic corticosteroids administered to ventilator dependent preterm neonates with birth weight </= 1500 grams or gestational age </= 32 weeks after two weeks of life for the treatment of evolving CLD.

SEARCH STRATEGY

Randomized and quasi-randomized trials were identified by searching the Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 2002), MEDLINE (1966 - September 2002), EMBASE (1980 - September 2002), CINAHL (1982 - September 2002), reference lists of published trials and abstracts published in Pediatric Research (1990 - April 2002) from the Society for Pediatric Research/Pediatric Academic Societies' Annual Meetings.

SELECTION CRITERIA

Randomized or quasi-randomized trials comparing inhaled versus systemic corticosteroid therapy (irrespective of the dose and duration of therapy) starting after the first two weeks of life in ventilator dependent very low birth weight preterm neonates.

DATA COLLECTION AND ANALYSIS

Data were extracted regarding clinical outcomes including CLD at 28 days or 36 weeks corrected gestational age (CGA), mortality, combined outcome of death or CLD at 28 days or 36 weeks CGA, other pulmonary outcomes and adverse effects. All data were analyzed using RevMan 4.1. When appropriate, meta-analysis was performed using relative risk (RR), risk difference (RD), and weighted mean difference (WMD) along with their 95% confidence intervals (CI). If RD was statistically significant, number needed to treat (NNT) was calculated.

MAIN RESULTS

Five trials comparing inhaled versus systemic corticosteroids in the treatment of CLD were identified. Two trials were excluded as both included non ventilator dependent patients. One trial is awaiting assessment and clarification of published data. Two trials qualified for inclusion in this review. Halliday et al (Halliday 2001a) randomized infants < 72 hours, while Suchomski et al (Suchomski 2002) randomized at 12-21 days. Although the steroids were commenced after the first 2 weeks of life in both the trials, the outcomes were measured over different time periods, from the age at randomization in each trial, making it inappropriate to combine results. In neither trial was there a statistically significant difference between the groups in the incidence of CLD at 36 weeks CGA amongst all randomized infants. The estimates for the trial by Halliday et al (Halliday 2001a) were RR 1.10 (95% CI 0.82, 1.47), RD 0.03 (95% CI -0.08, 0.15); number of infants (n) = 292 and for the trial by Suchomski et al (Suchomski 2002) RR 0.90 (95% CI 0.79, 1.02), RD -0.10 (95% CI -0.22, 0.02; n = 78 ). There were no statistically significant differences between the groups in either trial for oxygen dependency at 28 days, death by 28 days or 36 weeks, the combined outcome of death or CLD by 28 days or 36 weeks CGA, duration of intubation, duration of oxygen dependence, or adverse effects. Information on the long term neurodevelopmental outcomes was not available.

REVIEWER'S CONCLUSIONS

This review found no evidence that inhaled corticosteroids confer net advantages over systemic corticosteroids in the management of ventilator dependent preterm infants. Neither inhaled steroids, nor systemic steroids, can be recommended as standard treatment for ventilated preterm infants. There was no evidence of difference in effectiveness or side-effect profiles for inhaled versus systemic steroids. A better delivery system guaranteeing selective delivery of inhaled steroids to the alveoli might result in beneficial clinical effects without increasing side-effects. To resolve this issue, studies are needed to identify the risk/benefit ratio of different delivery techniques and dosing schedules for the administration of these medications. The long term effects of inhaled steroids, with particular attention to neurodevelopmental outcome, should be addressed in future studies.

Disseminated aspergillosis inciting intestinal ischaemia and obstruction

Invasive aspergillosis is an opportunistic infection that characteristically affects the immunocompromised host, resulting in a high degree of morbidity and mortality. Although the portal of entry is usually pulmonary, there are rare reports of invasive aspergillosis localized to the gastrointestinal tract. In addition, haematological spread may develop, with life threatening disseminated infection involving the vital organs and the gastrointestinal tract. Although disseminated infection is well recognized, the CT findings of gastrointestinal disease have not been reported to our knowledge. We describe the CT findings in a patient with invasive aspergillosis involving the gastrointestinal tract, which resulted in intestinal ischaemia complicated by small bowel obstruction.

Retropharyngeal aberrant thymus

INTRODUCTION

Upper airway obstruction from a retropharyngeal mass requires urgent evaluation. In children, the differential diagnosis includes infection, trauma, neoplasm, and congenital abnormalities. Aberrant cervical thymic tissue, although occasionally observed on autopsy examination, is rarely clinically significant. We present the case of an infant with respiratory distress attributed to aberrant thymic tissue located in the retropharyngeal space.

CASE

A 6-week-old infant was brought to the emergency department for evaluation of stridor associated with periodic episodes of cyanosis. Lateral neck radiograph revealed widening of the retropharyngeal soft tissues. The patient's symptoms did not improve with intravenous ampicillin-sulbactam. Magnetic resonance imaging (MRI) performed on the seventh day of hospitalization revealed a retropharyngeal mass that extended to the carotid space. The mass was easily resected using an intraoral approach. Microscopic examination demonstrated thymic tissue. A normal thymus was also observed in the anterior mediastinum on MRI. The patient recovered uneventfully and had no further episodes of stridor or cyanosis.

DISCUSSION

Aberrant cervical thymic tissue may be cystic or solid. Cystic cervical thymus is more common, and 6% of these patients present with symptoms of dyspnea or dysphagia. Aberrant solid cervical thymus usually presents as an asymptomatic anterior neck mass. This case is unusual in that solid thymic tissue was located in the retropharynx, a finding not previously reported in the English literature. Additionally, the patient presented in acute respiratory distress, and the diagnosis was confounded by the presence of mild laryngomalacia. In retrospect, our patient likely had symptoms of intermittent upper airway obstruction since birth. The acute respiratory distress at presentation was likely the result of laryngomalacia exacerbated by the presence of aberrant thymic tissue and a superimposed viral infection. Aberrantly located thymic tissue arises as a consequence of migrational defects during thymic embryogenesis. The thymus is a paired organ derived from the third and, to a lesser extent, fourth pharyngeal pouches. After its appearance during the sixth week of fetal life, it descends to a final position in the anterior mediastinum, adjacent to the parietal pericardium. Aberrant thymic tissue results when this tissue breaks free from the thymus as it migrates caudally. Therefore, aberrant thymic tissue may be found in any position along a line from the angle of the mandible to the sternal notch, and in the anterior mediastinum to the level of the diaphragm. In an autopsy study of 3236 children, abnormally positioned thymic tissue was found in 34 cases (1%). The aberrant thymus was most often located near the thyroid gland (n = 19 cases) but was also detected lower in the anterior neck (n = 6 cases), higher in the anterior neck (n = 8 cases), and at the left base of the skull (n = 1 case). The presence of thymic tissue in the retropharyngeal space in our patient is more unusual given the typical embryologic origin and descent of the thymus in the anterior neck to the mediastinum. Children with aberrant thymus may have associated anomalies. Twenty-four of 34 children (71%) with aberrant thymus detected at autopsy had features consistent with DiGeorge syndrome, and only 5 of the remaining 10 patients had a normal mediastinal thymus present. Our patient had normal serum calcium levels after excision and a mediastinal thymus was visualized on MRI. Biospy is required for diagnosis of cervical thymus and should also be considered to exclude other causes. MRI is helpful in delineating the presence, position, and extent of thymic tissue. Immunologic sequelae or recurrence after resection of an aberrant cervical thymus has not been reported.

In vitro sealing of punctured fetal membranes: potential treatment for midtrimester premature rupture of membranes

OBJECTIVE

Midtrimester premature rupture of membranes causes significant perinatal morbidity and death. No effective treatment exists. We investigated (1) whether a needle puncture in the fetal membranes could be sealed in vitro and (2) the optimal composition of the sealant to be used.

STUDY DESIGN

Membranes from second trimester pregnancies (16-24 weeks of gestation) were stretched over a modified syringe with a 2.5-cm open diameter. The syringe was filled with 20 mL of second trimester amniotic fluid, and the membrane was punctured with a 20-gauge needle. Sealants were injected into the amniotic fluid. The primary outcome variable was time for leakage of amniotic fluid. Median times for leakage for the formulations were compared by Wilcoxon exact rank sum test.

RESULTS

Platelets alone failed to seal the puncture site. All other formulations stopped leakage temporarily. Tisseel (Baxter Corp, Glendale, Calif) and cryoprecipitate/thrombin preparations led to more prolonged sealing of punctured amniotic membranes than platelets (P <.01) and were not significantly different from each other.

CONCLUSION

Of the sealants tested in vitro, amniotic membranes are best sealed by a fibrin/thrombin-based sealant.

Nosocomial outbreak of Microbacterium species bacteremia among cancer patients

To date, only 6 sporadic Microbacterium species (formerly coryneform Centers for Disease Control and Prevention [CDC] groups A-4 and A-5) infections have been reported. The source, mode of transmission, morbidity, mortality, and potential for nosocomial transmission of Microbacterium species remain unknown. From 26 July through 14 August 1997, 8 episodes of coryneform CDC group A-5 symptomatic bacteremia occurred in 6 patients on the oncology ward at the Maine Medical Center. One patient died. All isolates were identified at CDC as Microbacterium species and had identical DNA banding patterns by pulsed-field gel electrophoresis. To assess risk factors for Microbacterium species infection, a retrospective cohort study was conducted. The presence of a central venous catheter was the strongest risk factor (6/6 vs. 22/48; relative risk, 3.2; P<.0001). This outbreak demonstrates significant Microbacterium species-associated morbidity and mortality in immunocompromised populations and confirms the potential for epidemic nosocomial transmission.

Effect of feedback on obstetrics and gynecology residents' teaching performance and attitudes

OBJECTIVE

To evaluate obstetrics and gynecology residents' teaching performance, perception of the importance of teaching and satisfaction with their evaluations after the institution of an oral or written medical student feedback and award system.

STUDY DESIGN

Residents at a single, university-based obstetrics and gynecology program were assigned to receive either oral, written or no medical student feedback on their teaching skills in a prospective, randomized, controlled trial. Students rated resident performance in seven teaching categories. Residents' scores per six-week block were evaluated for one year. Questionnaires addressing resident attitudes toward feedback were collected at baseline and at 6 and 12 months. All residents then received written feedback and public awards for high scores for an additional year.

RESULTS

After 12 months of feedback there were trends toward improvement in several of the teaching categories and overall evaluations. None of the controls, 29% of residents receiving oral feedback and 50% of residents receiving written feedback rated teaching as more important than before. None of the controls, 57% of those receiving oral feedback (P = NS) and 88% of those receiving written feedback (P = .009), for a total of 73% of residents receiving any feedback (P = .001), thought that the amount of feedback was adequate at 12 months. Follow-up of 15 residents after one year of written feedback with an award for high evaluations showed that 60% improved their overall scores. The mean overall group score improved.

CONCLUSION

A feedback and award system can lead to improved resident teaching performance as well as enhanced perception of residents' role as teachers and greater resident satisfaction.

Epidemiology of dyspepsia in the general population in Mumbai

BACKGROUND AND AIMS

Dyspepsia is a common complaint in the general population. The prevalence, demography and economic implications of dyspepsia in India are not known; we studied these using a detailed symptom questionnaire.

METHODS

2549 presumably healthy adults (mean age 37.2 [14.1] years; 1441 men) were interviewed. Gastrointestinal symptoms, their investigation and treatment, dietary history and history of addictions were noted. Dyspepsia was defined as abdominal fullness or upper abdominal pain present for at least one month; irritable bowel syndrome (IBS) was defined by Manning's criteria. Based on the symptom profile, subjects were divided into three broad groups: no dyspepsia (n=1695; 945 men), dyspepsia with (110; 63 men) or without (664; 382 men) IBS, and IBS alone (80; 51 men).

RESULTS

774 subjects (30.4%) had dyspepsia; the median (range) duration of symptoms was 24 (1-360) months. Abdominal fullness (n=614), abdominal pain (374), heartburn (272) and belching (271) were the most common symptoms; significant symptoms (present at least once a week) occurred in 306 subjects (12.0% of the population). More than half the subjects had symptoms suggestive of mixed type of dyspepsia; dysmotility-like dyspepsia was the next most common (n=257; 33.2%). The frequency of dyspepsia was not related to type of diet or consumption of spices. Dyspepsia was more prevalent in subjects who abused tobacco or alcohol. Three hundred and twenty-one subjects with dyspepsia (41.4%) had visited a physician for their complaints and had received treatment with antacids, acid suppressors or prokinetic drugs; 4.5% and 7.2% had undergone previous endoscopy and ultrasonography, respectively; dyspeptic subjects underwent more investigations (p<0.001) than those with IBS.

CONCLUSIONS

Dyspepsia is reported by almost one-third of the population in Mumbai; significant symptoms occur in 12%. Forty percent of these subjects receive treatment and only a small number undergo endoscopy or ultrasonography.

Symptoms of dry eye and recurrent erosion syndrome after refractive surgery

PURPOSE

To determine the incidence and severity of patient complaints typical of dry eye and recurrent erosion syndrome after excimer laser refractive surgery and to compare the incidence of these symptoms after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).

SETTING

Outpatient university practice.

METHODS

A questionnaire was mailed to 1731 patients who had had primary myopic PRK or LASIK at least 6 months previously. Questions were designed to determine the incidence and character of ocular dryness and recurrent erosion symptoms and their impact on patient satisfaction and willingness to have surgery again. Responses from PRK and LASIK patients were compared.

RESULTS

Responses from 231 PRK patients and 550 LASIK patients revealed an incidence of dryness symptoms in 43% and 48%, respectively (P >.05). Soreness of the eye to touch was reported by 26.8% and 6.7%, respectively (P <.0001). Sharp pains occurred in 20.4% of PRK patients and 8.0% of LASIK patients (P =.0001). Complaints of the eyelid sticking to the eyeball occurred in 14.7% and 5.6%, respectively (P =.0001). All symptoms occurred predominantly on waking. Frequency of eyelid sticking (P <.0005) and sharp pain (P <.005) symptoms, as well as severity of sharp pain symptoms (P <.0001), were significantly greater in PRK patients than in LASIK patients. On a scale of 0 to 10 (10 high), median overall patient satisfaction with surgery was 9 in both groups. Soreness of the eyelid to touch occurred significantly more frequently among patients with symptoms of sharp pains on waking (P <.001) and the sensation of the eyelid sticking to the eyeball (P <.001). Patients with 1 or more symptoms were twice as likely as asymptomatic patients to have a satisfaction score of less than 8 (P <.001).

CONCLUSIONS

Ocular dryness symptoms occurred commonly after PRK and LASIK. Symptoms suggestive of mild recurrent erosions included sharp pains, the sensation of the eyelid sticking to the eyeball, and soreness of the eyelid to touch, a previously unrecognized symptom of this condition. These symptoms occurred commonly after excimer laser procedures but were significantly more common, more severe, and more prolonged after PRK. The presence of these symptoms had a significant effect on patient satisfaction.

Group C streptococcal meningitis: case report and review of the literature

Group C streptococci are a common cause of epidemic bacterial infection in animals. These organisms are a rare but frequently fatal cause of meningitis in humans. We report the case of a 13-year-old girl with meningitis caused by a group C Streptococcus (Streptococcus zooepidemicus) successfully treated with vancomycin and third generation cephalosporins. We also review cases of group C streptococcal meningitis reported previously.

Random circular permutation leading to chain disruption within and near alpha helices in the catalytic chains of aspartate transcarbamoylase: effects on assembly, stability, and function

A collection of circularly permuted catalytic chains of aspartate transcarbamoylase (ATCase) has been generated by random circular permutation of the pyrB gene. From the library of ATCases containing permuted polypeptide chains, we have chosen for further investigation nine ATCase variants whose catalytic chains have termini located within or close to an alpha helix. All of the variants fold and assemble into dodecameric holoenzymes with similar sedimentation coefficients and slightly reduced thermal stabilities. Those variants disrupted within three different helical regions in the wild-type structure show no detectable enzyme activity and no apparent binding of the bisubstrate analog N:-phosphonacetyl-L-aspartate. In contrast, two variants whose termini are just within or adjacent to other alpha helices are catalytically active and allosteric. As expected, helical disruptions are more destabilizing than loop disruptions. Nonetheless, some catalytic chains lacking continuity within helical regions can assemble into stable holoenzymes comprising six catalytic and six regulatory chains. For seven of the variants, continuity within the helices in the catalytic chains is important for enzyme activity but not necessary for proper folding, assembly, and stability of the holoenzyme.

Apolipoprotein deficiency and chronic liver disease

Deficiency of apolipoprotein can be of genetic origin or due to diseases like advanced chronic liver disease. Deficiency of apolipoprotein A causes Tangier disease without any major hepatic involvement being reported. Deficiency of apolipoprotein B causes abetalipoproteinemia or familial hypobetalipoproteinemia; with hepatic involvement in the form of raised transaminases, fatty liver and cirrhosis. Advanced chronic liver disease itself can cause reduction of apolipoprotein A and apolipoprotein B levels and acanthocytosis. In patients with chronic liver disease of undetermined etiology, lipid profile and apolipoprotein levels should be obtained routinely. If it suggests apolipoprotein B deficiency, then liver biopsy can be avoided, as the etiology of chronic liver disease is established. Isolated deficiency of either apolipoprotein A or apolipoprotein B suggests etiology of chronic liver disease, while deficiency of both apolipoprotein A and apolipoprotein B is a manifestation of advanced chronic liver disease.

Interaction of cigarette smoke and house dust mite allergens on inflammatory mediator release from primary cultures of human bronchial epithelial cells

Several studies have shown that exposure to cigarette smoke and/or house dust mite (HDM) can lead to increased airway inflammation in susceptible individuals. The underlying mechanisms, however, are not defined. To investigate the interaction between cigarette smoke and HDM allergen on mediator release from primary cultures of human bronchial epithelial cells. Confluent human bronchial epithelial cell cultures were exposed to cigarette smoke in the absence or presence of HDM allergen and investigated for the release of IL-8, IL-1beta, and sICAM-1. Damage to the epithelial cells themselves was assessed by release of 51Cr. On separate occasions, we investigated the effect of PTL11028, a highly potent and selective Der p1 inhibitor, on HDM allergen-induced release of IL-8, following activation of HDM allergen by incubation with cysteine. The effect of cigarette smoke exposure on the stability of these released mediators in prepared solutions in the absence/presence of reduced glutathione was also studied. Both HDM allergens and short-term (20 min) cigarette smoke exposure led to a significantly increased release of IL-8, IL-1beta and sICAM-1 from the epithelial cell cultures. Longer exposure (1-6 h) to cigarette smoke led to a dramatic decrease in the amount of these mediators detected in the culture medium. Whilst incubation of epithelial cultures with HDM allergen did not cause any significant change in the release of 51Cr from pre-loaded cells, cigarette smoke on its own led to a marked, exposure and incubation-time dependent increase in the release of 51Cr. Incubation with HDM allergen led to a significant, dose and time-dependent increase in the release of IL-8, which was further enhanced when the allergen extract was pre-activated with cysteine. This effect was completely abrogated by PTL11028, a novel Der p1 inhibitor. Prepared solutions of various concentrations of IL-8, IL-1beta and sICAM-1 exposed to cigarette smoke demonstrated a dramatic exposure time-dependent decrease in the detectable amount of these mediators, an effect which was abrogated by GSH. HDM-induced airway inflammation may include Der p-mediated release of inflammatory mediators from epithelial cells. Additionally, short-term cigarette smoke exposure may induce airway inflammation by release of inflammatory mediators from these cells, an effect which may be potentiated by Der p allergens. Longer term cigarette smoke exposure may cause damage to epithelial cells and changes in the structure of inflammatory mediators.

Fatty liver and elevated transaminases with heterozygous apolipoprotein B deficiency

Asymptomatic fatty liver and elevated transaminases is a common occurrence with varied etiology. Apolipoprotein (apo) B deficiency is an uncommon cause of fatty liver and elevated transaminases. The typical lipid profile low cholesterol low LDL (low density lipoprotein) suggests diagnosis of apo B deficiency and an invasive procedure like liver biopsy can be avoided in such patients.

Real time intraocular pressure and lamellar corneal flap thickness in keratomileusis

BACKGROUND

To measure real time intraocular pressure (IOP) during keratomileusis and to determine variability of corneal flap thickness by using different suction ring pressure settings.

METHODS

Eight human cadaver eyes, two groups of four each, were used. The suction ring of the UniversalKeratome was applied to each eye, the same as for a standard automated lamellar keratoplasty (ALK) or laser in situ keratomileusis (LASIK) procedure, to create a lamellar corneal flap. The pressure of the suction ring on each eye was raised to one of two different levels, four eyes to 488 and the remaining four to 600 mm Hg. IOP was continuously recorded by manometer, from application of the suction ring through the end of the passage of the microkeratome. Central corneal thickness was measured, both before and after each procedure.

RESULTS

IOP increased by >90 mm Hg after application of the suction ring at a pressure of either 488 mm Hg or 600 mm Hg. Corneal flaps performed under a suction ring pressure of 488 mm Hg measured 159.98+/-5 microm, whereas flap thickness for the 600-mm Hg group varied 1.4-266.2 microm. Two flaps exhibited irregular configurations.

CONCLUSIONS

Real time IOP can be measured during keratomileusis. The results demonstrated a significant increase in IOP during the procedure. Suction ring pressure setting is an important variable in determining consistent corneal flap thickness during the keratomileusis procedure.

Cigarette smoke decreases the expression of secretory component in human bronchial epithelial cells, in vitro

Epithelial secretory component (SC) is thought to be essential for immunologic protection of the respiratory tract from viral and bacterial infection, since it transports polymeric IgA from the basolateral to the luminal surface of epithelial cells. We have hypothesized that recurrent infection in airways of cigarette smokers is at least partly a consequence of cigarette smoke-induced downregulation of the expression and/or release of SC from airway epithelial cells, subsequently resulting in decreased transcytosis of secretory IgA to the airway lumen. To test this hypothesis, we have cultured human bronchial epithelial cells (HBEC) from surgical tissues and exposed these for 20 minutes to either air or cigarette smoke. Following exposure to cigarette smoke the HBEC cultures were incubated for a further period of up to 24 h, during which time separate cultures were processed by immunocytochemistry for the presence of SC, in a time-dependent manner. The stained HBEC cultures were evaluated by colour image analysis for the percentage of total cells staining for SC. Exposure to cigarette smoke significantly decreased the percentage of total HBEC staining for secretory component from a baseline value (median and interquartile[IQ]1, IQ3) of 35.9% (26.5, 41.6) to 15.7% (8.2, 25.4; p < 0.05) 1 h after exposure, compared with exposure to air. The percentage of cells staining for secretory component were further reduced to 5.3% (3.3, 6.4; p < 0.01), 6 h after exposure, compared to exposure to air. After incubation for 24 h following exposure to cigarette smoke, there was gross cell damage and the cells were not suitable for immunocytochemical analysis. These results suggest that short-term exposure to cigarette smoke may compromise the immune barrier function of the airway mucosa by decreasing the expression and/or release of epithelial SC, thereby decreasing the transcytosis of IgA necessary for inactivating the microbial pathogens in the airway lumen.

Prevention of perinatal HIV transmission during pregnancy

Transmission of the human immunodeficiency virus (HIV) from mother to child can occur in utero, during labour or after delivery from breastfeeding. The majority of infants are infected during delivery. Maternal HIV-1 plasma viral load at delivery is the most important predictor of vertical transmission. For this reason, efforts to interrupt transmission have focused on the use of antiretroviral therapy. Zidovudine has been shown to reduce significantly vertical HIV transmission when used antepartum and intrapartum by the mother and postpartum by the newborn for 6 weeks. However, zidovudine monotherapy increases the risk of developing zidovudine resistance and may jeopardize the goal of durable viral suppression and allow HIV disease progression in the mother and transmission to the infant. Potent antiretroviral therapy is now recommended for all HIV-infected pregnant women using the same criteria for non-pregnant individuals. If possible, combination antiretroviral regimens should include the use of zidovudine but not at the expense of long-term viral suppression. The use of elective Caesarean section should probably be reserved for women who fail to achieve viral suppression at the time of delivery or if indicated for obstetrical reasons. The practice of breastfeeding has been shown to diminish the long-term efficacy of perinatal antiretroviral therapy. All HIV-infected mothers should avoid breastfeeding the newborn if possible. This review summarizes major prospective and retrospective antiretroviral treatment studies in HIV-infected pregnant women. Pharmacokinetic information as it relates to pregnancy and adverse event profiles of antiretroviral agents are also discussed. The impact of recent advances in the management of HIV infection in pregnancy is discussed with regard to their feasibility in resource-poor countries.

Management of HIV infection during pregnancy

Optimal management of HIV infection in pregnancy requires maternal use of potent antiretroviral therapy to prevent disease progression in the mother and vertical transmission to the newborn. Combination antiretroviral therapy substantially reduces the risk of perinatal HIV transmission and appears to be more effective than zidovudine monotherapy. The administration of single dose nevirapine to mother intrapartum and infant postpartum effectively reduces vertical HIV transmission and is less costly and cumbersome than zidovudine regimens. Elective cesarean section reduces vertical transmission of HIV but its benefit is less clear when antiretroviral therapy decreases maternal plasma HIV viral load to low levels at delivery. If possible, HIV-infected mothers should avoid breastfeeding. The present review discusses the importance of early identification of maternal HIV infection, strict adherence to combination antiretroviral regimens to prevent drug resistance, developing a better understanding of antiretroviral pharmacokinetics in pregnancy and short/long term safety of anti-HIV drugs.

Risks associated with renal dysfunction in patients in the coronary care unit

OBJECTIVES

The purpose of this study was to quantify the impact of baseline renal dysfunction on morbidity and mortality in patients in the coronary care unit (CCU).

BACKGROUND

The presence of renal dysfunction is an established independent predictor of survival after acute myocardial infarction and revascularization procedures.

METHODS

We analyzed a prospective CCU registry of 12,648 admissions by 9,557 patients over eight years at a single, tertiary center. Admission serum creatinine was available in 9,544 patients. Those not on long-term dialysis were classified into quartiles of corrected creatinine clearance, with cut-points of 46.2, 63.1 and 81.5 ml/min per 72 kg. Dialysis patients (n = 527) were considered as a fifth comparison group.

RESULTS

Baseline characteristics, including older age, African-American race, diabetes, hypertension, previous coronary disease and heart failure, were incrementally more common across increasing renal dysfunction strata. There were graded increases in the relative risk for atrial and ventricular arrhythmias, heart block, asystole, development of pulmonary congestion, acute mitral regurgitation and cardiogenic shock across the risk strata. Survival analysis demonstrated an early mortality hazard for those with renal dysfunction, but not on dialysis, for the first 60 months, followed by graded decrements in survival across increasing renal dysfunction strata.

CONCLUSIONS

Baseline renal function is a powerful predictor of short- and long-term events in the CCU population. There is an early hazard for in-hospital and postdischarge mortality for those with a corrected creatinine clearance <46.2 ml/min per kg, but not on dialysis.

Cytokeratin expression in the odontogenic keratocyst

PURPOSE

This study attempted to identify differential cytokeratin expression in cystic jaw lesions using immunohistochemical staining.

PATIENTS AND METHODS

The charts from selected patients treated between 1983 and 1994 for jaw cysts were evaluated. Twenty-four paraffinized specimens were selected randomly for investigation with 5 immunohistochemical stains. The 4 diagnostic categories included ameloblastoma, dentigerous cyst, odontogenic keratocyst (OKC), and recurrent odontogenic keratocyst in patients with nevoid basal cell carcinoma (NBCC) syndrome. The 5 immunohistochemical stains included antibodies to cytokeratins 13, 17, and 18; CAM 5.2; AE 1/3; and carcinoembryonic antigen (CEA).

RESULTS

Differential staining of OKCs from patients with and without NBCC syndrome was found only with the antibody to cytokeratin 17. Furthermore, staining of OKCs in syndromic patients appeared to be stronger and more uniform than in nonsyndromic patients.

CONCLUSIONS

These findings suggest that immunohistochemical staining for cytokeratin 17 may aid in the diagnosis of OKCs and may be used to further subdivide these lesions based on the presence or absence of NBCC syndrome.

Quantitative topographic irregularity as a predictor of spectacle-corrected visual acuity after refractive surgery

PURPOSE

To evaluate a new topographic index called topographic irregularity as a quantitative predictor of corrected vision after refractive surgery.

METHODS

We defined topographic irregularity as the summed difference at all points between a topographic refractive corneal power map and its best-fit spherocylinder. We prospectively studied 107 eyes of 107 patients 3 months after a variety of refractive procedures. Topographic irregularity was calculated from topographic maps, and the correlation between topographic irregularity and spectacle-corrected visual acuity was determined using both high-contrast and low-contrast acuity charts. This correlation was compared with correlations for the surface regularity index and the surface asymmetry index. Next, we analyzed 54 of these topographic maps to create a regression scale relating surface regularity index, surface asymmetry index, and topographic irregularity to predict spectacle-corrected visual acuity. This scale was then used to predict spectacle-corrected visual acuity on the remaining 53 postoperative patients.

RESULTS

The correlation of topographic irregularity with spectacle-corrected visual acuity (R(2) =.36) was comparable to the correlation for the surface regularity index (R(2) =.36) and stronger than for the surface asymmetry index (R(2) =.11) when spectacle-corrected visual acuity was measured with high-contrast eye charts. Topographic irregularity correlated more strongly with spectacle-corrected visual acuity (R(2) =.42) than either the surface regularity index (R(2) =.28) or the surface asymmetry index (R(2) =.14) when spectacle-corrected visual acuity was measured with low-contrast eye charts. Using the regression scale, prediction of high-contrast and low-contrast spectacle-corrected visual acuity from topographic irregularity was superior to or comparable to predictions using the surface regularity index and the surface asymmetry index.

CONCLUSIONS

Topographic irregularity has a closer correlation with spectacle-corrected visual acuity than existing topographic indexes. Topographic irregularity is also an accurate predictor of spectacle-corrected visual acuity and may be a more sensitive tool for evaluating postoperative visual performance than current topographic measures.

Diagnosis and Management of Infectious Thyroiditis

A broad range of disorders can cause inflammation of the thyroid gland. True thyroid infections are rare and can result from a variety of microorganisms, of which bacteria are the most common. Other rarer pathogens include fungi, parasites, and viruses. Gram-positive bacteria, especially staphylococci, predominate as causative agents in adults and children. In immunocompromised patients, opportunistic pathogens have been isolated. Most infections in adults occur as a result of hematogenous or lymphatic seeding of the thyroid gland. In children, congenital anomalies can lead to thyroid infection and require surgical correction to prevent recurrence. Fine-needle aspiration of the thyroid is usually required to identify the infecting agent, and prolonged antimicrobial therapy with or without surgical drainage is the cornerstone of management. This review outlines the pathogenesis, microbiology, diagnosis, and management of infectious thyroiditis in adults and children and compares this disorder with other, more common causes of thyroid inflammation.

Phase Behavior, Structure, and Physical Properties of the Quaternary System Tetradecyldimethylamine Oxide, HCl, 1-Hexanol, and Water

The phase diagram of the ternary surfactant system tetradecyldimethylamine oxide (TDMAO)/HCl/1-hexanol/water shows with increasing cosurfactant concentration an L(1) phase, two L(alpha) phases (a vesicle phase L(alpha1) and a stacked bilayer phase L(alphah)), and an L(3) phase, which are separated by the corresponding two-phase regions L(1)/L(alpha) and L(alpha)/L(3). In this investigation, the system was studied where some of the TDMAO was substituted by the protonated TDMAO. Under these conditions, one finds for constant surfactant concentration of 100 mM TDMAO a micellar L(1) phase, an L(alpha1) phase (consisting of multilamellar vesicles), and an interesting isotropic L(1)(*) phase in the middle of the L(1)/L(alpha) two-phase region. The L(1)(*) phase exists at intermediate degrees of charging of 30-60% and for 40-120 mM TDMAO and 70-140 mM hexanol concentration. At surfactant concentrations less than 80 mM the L(1)(*)-phase borders directly on the L(1) phase. The phase transition between the L(1) phase and the L(1)(*) phase was detected by electric conductivity and rheological measurements. The conductivity values show a sharp drop at the L(1)/L(1)(*) transition, and the zero shear viscosity of the L(1)(*) phase is much lower than in L(1) phase. The form and size of the aggregates in L(1)(*) were detected with FF-TEM and SANS. This phase contains small unilamellar vesicles (SUV) of about 10 nm and some large multilamellar vesicles with diameters up to 500 nm. The system exhibits another peculiarity. For 100 mM surfactant, the clear L(alpha1)-phase exists only at chargings below 30%. With oscillating rheological measurements a parallel development of the storage modulus G' and the loss modulus G" was observed. Both moduli are frequency independent and the system possesses a yield stress. The storage modulus is a magnitude larger than the loss modulus. Copyright 2000 Academic Press.