Reference change value of global longitudinal strain in clinical practice: A test-rest quality implementation project

BACKGROUND

Reference change value (RCV) is used to assess the significance of the difference between two measurements after accounting for pre-analytic, analytic, and within-subject variability. The objective of the current study was to define the RCV for global longitudinal strain (GLS) using different semi-automated software in standard clinical practice.

METHODS

Using a test-retest study design, we quantified the median coefficient of variation (CV) for GLS using AutoStrain and Automated Cardiac Motion Quantification (aCMQ) by Philips. Triplane left-ventricular ejection fraction (LVEF) was measured for comparison. Multivariable regression analysis was performed to determine factors influencing test-retest CV including image quality and the presence of segmental wall motion abnormalities (WMA). RCV was reported using a standard formula assuming two standard deviations for repeated measurements; results were also translated into Bayesian probability. Total measurement variation was described in terms of its three different components: pre-analytic (acquisition), analytic (measuring variation), and within-subject (biological) variation.

RESULT

Of the 44 individuals who were screened, 41 had adequate quality for strain quantification. The mean age of the cohort was 56.4 ± 16.8 years, 41% female, LVEF was 55.8 ± 9.8% and the median and interquartile range for LV GLS was -17.2 [-19.3 to -14.8]%. Autostrain was more time efficient (80% less analysis time) and had a lower total median CV than aCMQ (CV = 7.4% vs. 17.6%, p < .001). The total CV was higher in patients with WMA (6.4% vs. 13.2%, p = .035). In non-segmental disease, the CV translates to a RCV of 15% (corresponding to a probability of real change of 80%). Assuming a within-subject variability of 4.0%, the component analysis identified that inter-reader variability accounts for 3.7% of the CV, while acquisition variability accounts for 4.0%.

CONCLUSION

Using test-retest analysis and CVs, we find that an RCV of 15% for GLS represents an optimistic estimate in routine clinical practice. Based on our results, a higher RCV of 17%-21% is needed in order to provide a high probability of clinically meaningful change in GLS in all comers. The methodology presented here for determining measurement reproducibility and RCVs is easily translatable into clinical practice for any imaging parameter.

Routine screening for hepatitis C in pregnancy is cost-effective in a large urban population in Ireland: a retrospective study

OBJECTIVE

To investigate whether risk factor-based screening in pregnancy is failing to identify women with hepatitis C virus (HCV) infection and to assess the cost-effectiveness of universal screening.

DESIGN

Retrospective study and model-based economic evaluation.

SETTING

Two urban tertiary referral maternity units, currently using risk factor-based screening for HCV infection.

POPULATION

Pregnant women who had been tested for hepatitis B, HIV but not HCV.

METHODS

Anonymised sera were tested for HCV antibody. Positive sera were tested for HCV antigen. A cost-effectiveness analysis of a change to universal screening was performed using a Markov model to simulate disease progression and Monte Carlo simulations for probabilistic sensitivity analysis.

MAIN OUTCOME MEASURES

Presence of HCV antigen and cost per quality-adjusted life year (QALY).

RESULTS

In all, 4655 samples were analysed. Twenty had HCV antibodies and five HCV antigen. This gives an active infection rate of 5/4655, or 0.11%, compared with a rate of 0.15% in the risk-factor group. This prevalence is 65% lower than a previous study in the same hospitals from 2001 to 2005. The calculated incremental cost-effectiveness ratio (ICER) for universal screening was €3,315 per QALY gained.

CONCLUSION

This study showed that the prevalence of HCV infection in pregnant women in the Dublin region has declined by 65% over the past two decades. Risk factor-based screening misses a significant proportion of infections. A change to universal maternal screening for hepatitis C would be cost-effective in our population.

TWEETABLE ABSTRACT

Universal maternal screening for hepatitis C is cost-effective in this urban Irish population.

Early Onset Neonatal E.Coli Sepsis

This was a retrospective case-control study over 14 years comparing characteristics of neonates who developed E.coli bacteraemia with matched infant controls whose mothers were colonised with E.coli on high vaginal swab but who did not develop bacteraemia. Data was obtained from maternal and neonatal charts, the laboratory data-base was analysed to identify possible risk factors for E.coli bacteraemia. 21 cases and 38 controls were identified. The data showed no difference in gender, maternal age, white cell count, or cord pH. Significant differences were found in gestation (33 vs. 39.5wks p<0.01), weight (1.64 vs. 3.08 kg p<0.001) and duration of preterm, pre-labour rupture of membranes (pPROM) (6 vs. 2.9 days p=0.04) between cases and controls. Risk factors for E.coli bacte-raemia were identified, most notably duration of pPROM. A re-evaluation of antimicrobial therapy in neonates with a maternal pPROM >5 days is advised.

Neonatal Bacteraemia Among 112,360 Live Births

Our aims were to determine the incidence of bacteraemia in a cohort of neonatal patients over a 14 year period, to describe the organisms involved, and to establish the rates of sepsis with regard to both early onset sepsis (EOS) and late onset sepsis (LOS). Lastly, we investigated the trends of neonatal sepsis, to determine whether changes in clinical practice influenced the rate of blood culture positivity. With regards to EOS, GBS was the predominant pathogen, followed by E.coli, CoNS, and S. aureus . The overall mean EO rate per 1000 live births (LBs) was 1.19. Looking at LOS, S. aureus , CoNS , Enterococcus spp. were the most common bacteria cultured. The mean LOS rate was 1.88 per 1000 live births. The overall rate of EOS remained fairly steady. GBS remains the major pathogen in EOS; however its incidence has remained largely unchanged over time in relation to both EOS and LOS. Conversely the rate of LOS peaked from 2005-2009, mainly due to an increase in Staphylococcus aureus , CoNS and Enterococcus spp. cases, and then improved dramatically in the following years. This was likely due to a change in hospital policies in relation to hand hygiene and intravenous line placement and maintenance.

Screening for asymptomatic urogenital Chlamydia trachomatis infection at a large Dublin maternity hospital: results of a pilot study

BACKGROUND

There are currently no Irish guidelines on screening for Chlamydia trachomatis infection in pregnancy. Prevalence rates in the antenatal population are not known which has prevented the development of screening recommendations for this group.

AIMS

The objective of this study was to determine the prevalence of asymptomatic urogenital C. trachomatis infection in young women attending for care at a large maternity hospital.

METHODS

All patients aged 25 years and under attending the Hospital between December 2011 and December 2013 were offered screening for urogenital C. trachomatis infection. Nucleic acid amplification testing of the C. trachomatis cryptic plasmid was performed on either endocervical swabs or first void urine samples.

RESULTS

There were 2687 women tested for C. trachomatis infection, 83.4 % (2241/2687) through the antenatal clinics, 7.1 % (193/2687) through the gynaecology clinic, and 9.4 % (253/2687) through the emergency department. The rate of a positive test result was 5.6 % (151/2687) overall. The rates in women ages 16-18, 19-21 and 22-25 years were 9.1 % (31/340), 6.5 % (50/774) and 4.4 % (69/1561), respectively. A positive test result was more likely in those who were unemployed (p = 0.04), those who were Irish (p = 0.03) and those who were unmarried (p < 0.01). There were no cases of neonatal C. trachomatis infection in babies born to mothers who were screened in early pregnancy.

CONCLUSIONS

The prevalence rate of detected C. trachomatis infection was 5.6 % in the study population. Screening of antenatal patients may have a role in preventing vertical transmission of infection to the neonate.

Augmentative and Alternative Communication (AAC) for adults with severe aphasia: where we stand and how we can go further

PURPOSE

To review literature specific to the use of AAC with adults who have severe aphasia.

METHOD

The authors reviewed studies involving AAC interventions for adults with severe aphasia.

RESULTS

Published data support the use of aided and unaided AAC with adults with severe aphasia in controlled treatment contexts. Reported gains in communication typically have not generalized to everyday settings.

CONCLUSIONS

The application of AAC with persons with severe aphasia must address factors potentially limiting treatment success outside of training environments.

Phase I trial of docetaxel (D) plus samarium153 (Sm 153) in patients (pts) with hormone refractory prostate cancer (HRPC)

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Background: Bone targeted approaches hold great promise for improving outcomes in HRPC. Docetaxel (D) and samarium 153 (Sm153 ) have individually demonstrated a clinical benefit and preclinical data strongly support biological synergism in HRPC. Preclinical data suggests that 24 hour after a dose of D, there is maximum G2M arrest. This results in the accumulation of cells in the most radiosensitive phase of the cell cycle. This phase I trial was designed to evaluate toxicity and preliminary efficacy of combined D and Sm153 administered sequentially in advanced HRPC. Methods: HRPC pts progressing after anti-androgen withdrawal; = 2 prior chemotherapy regimens; acceptable bone marrow, renal and hepatic function were eligible. Planned D treatment in 4 cohorts (N=3/cohort) includes: Cohort 1: D 50mg/m2 IV on days 1, 22, 91, and 112; cohort 2: D 75mg/m2 IV on days 1 and 22 followed by 50mg/m2 IV on days 91 and 112; cohort 3: D 75mg/m2 IV on days 1 and 22 followed by 75mg/m2 IV on days 91 and 112; cohort 4: D 75 mg/m2 IV on days 1, 22, 42, 91, 112, and 133. Sm 153 (1.0 mi/Kg) is administered IV days 2 and 92 of each cycle. Cycles are repeated Q 12 wks (max 2 cycles). The endpoint for this trial is dose limiting toxicity and maximal tolerated dose. Results: From 5/11/05 - 1/7/07 ten pts were enrolled. Median: age 69.5 yrs (range 58–76), ECOG performance status 1 (range 0–1), baseline PSA 76.65 ng/ml (range 9.6–1064 ng/ml ), prior hormonal manipulations 3 (range1–6). Three pts had prior taxotere and 3 pts had prior palliative RT. All had bone metastases and 2 also had soft tissue disease. Five pts completed 2 cycles of treatment as planned. Five pts had 1 cycle (one pt is on treatment, 3 pts had PD and 1 had prolonged grade 1 thrombocytopenia =3 wks). Nine of 10 pts had reversible grade 3 / 4 neutropenia (1 pt had reversible episode of neutropenia with fever). Seven of 7 symptomatic pts had improvement in pain. Four of 10 of pts had a 50 % decline in PSA level lasting = 4 weeks; no soft tissue disease responses. Conclusions: Our preliminary data suggest that Q 3 wk D and Q 3 month Sm153 may be administered simultaneously at full doses in extensively pretreated HRPC pts, with acceptable toxicity and significant activity. This study is supported by a grant from sanofi- aventis and Sm153 is provided by Cytogen.

No significant financial relationships to disclose.

Identification and regulatory analysis of rainbow trout tapasin and tapasin-related genes

Tapasin (TAPBP) is a key member of MHC class Ia antigen-loading complexes, bridging the class Ia molecule to the transporter associated with antigen presentation (TAP). As part of an ongoing study of MHC genomics in rainbow trout, we have identified two rainbow trout TAPBP genes (Onmy-TAPBP.a and .b) and a similar but distinct TAPBP-related gene (Onmy-TAPBP-R) that had previously only been described in mammals. Physical and genetic mapping indicate that Onmy-TAPBP.a is on chromosome 18 in the MHC class Ia region and that Onmy-TAPBP.b resides on chromosome 14 in the MHC class Ib region. There are also at least two copies of TAPBP-R, Onmy-TAPBP-R.a and Onmy-TAPBP-R.b, located on chromosomes 2 and 3, respectively. Due to the central role of TAPBP expression during acute viral infection, we have characterized the transcriptional profile and regulatory regions for both Onmy-TAPBP and Onmy-TAPBP-R. Transcription of both genes increased during acute infection with infectious hematapoeitic necrosis virus (IHNV) in a fashion indicative of interferon-mediated regulation. Promoter-reporter assays in STE-137 cells demonstrate that the trout TAPBP and TAPBP-R promoters respond to interferon regulatory factors, Onmy-IRF1 and Onmy-IRF2. Overall, TAPBP is expressed at higher levels than TAPBP-R in naïve tissues and TAPBP transcription is more responsive to viral infection and IRF1 and 2 binding.

A consolidated linkage map for rainbow trout (Oncorhynchus mykiss)

Androgenetic doubled haploid progeny produced from a cross between the Oregon State University and Arlee clonal rainbow trout (Oncorhynchus mykiss) lines, used for a previous published rainbow trout map, were used to update the map with the addition of more amplified fragment length polymorphic (AFLP) markers, microsatellites, type I and allozyme markers. We have added more than 900 markers, bringing the total number to 1359 genetic markers and the sex phenotype including 799 EcoRI AFLPs, 174 PstI AFLPs, 226 microsatellites, 72 VNTR, 38 SINE markers, 29 known genes, 12 minisatellites, five RAPDs, and four allozymes. Thirty major linkage groups were identified. Synteny of linkage groups in our map with the outcrossed microsatellite map has been established for all except one linkage group in this doubled haploid cross. Putative homeologous relationships among linkage groups, resulting from the autotetraploid nature of the salmonid genome, have been revealed based on the placement of duplicated microsatellites and type I loci.

A phase I trial of CV706, a replication-competent, PSA selective oncolytic adenovirus, for the treatment of locally recurrent prostate cancer following radiation therapy

CV706 is a prostate-specific antigen (PSA)-selective, replication-competent adenovirus that has been shown to selectively kill human prostate cancer xenografts in preclinical models. To study the safety and activity of intraprostatic delivery of CV706, a Phase I dose-ranging study for the treatment of patients with locally recurrent prostate cancer after radiation therapy was conducted. Twenty patients in five groups were treated with between 1 x 10(11) and 1 x 10(13) viral particles delivered by a real-time, transrectal ultrasound-guided transperineal technique using a three-dimensional plan. The primary end point was the determination of treatment-related toxicity. Secondary objectives included evaluation of the antitumor activity of CV706 and monitoring for other correlates of antineoplastic action. In this study, CV706 was found to be safe and was not associated with irreversible grade 3 or any grade 4 toxicity. No grade >1 alterations in liver function tests associated with CV706 administration were observed. Posttreatment prostatic biopsies and detection of a delayed "peak" of circulating copies of virus provided evidence of intraprostatic replication of CV706. The study defined the timing of CV706 shedding into blood and urine as well as the appearance of circulating Ad5 neutralizing antibodies. Finally, this study documents the serum PSA response of treated patients and reveals a dose response showing that all five patients who achieved a > or =50% reduction in PSA were treated with the highest two doses of CV706. This study represents the first clinical translation of a prostate-specific, replication-restricted adenovirus for the treatment of prostate cancer. Taken together, this study documents that intraprostatic delivery of CV706 can be safely administered to patients, even at high doses, and the data also suggest that CV706 possesses enough clinical activity, as reflected by changes in serum PSA, to warrant additional clinical and laboratory investigation.

The effects of intravenous doxycycline therapy for rheumatoid arthritis: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

To determine the feasibility, safety, and potential clinical efficacy of intravenous (IV) doxycycline therapy for rheumatoid arthritis (RA), as well as its possible effects on serum and urinary markers of collagen breakdown.

METHODS

The exploratory trial was designed as a 16-week, single-center, randomized, double-blind, placebo-controlled trial. Eligible subjects with active seropositive or erosive RA were randomly allocated into 3 treatment groups: doxycycline 200 mg IV, azithromycin 250 mg orally, or placebo. The blinded IV study drug was administered once daily for the first 3 weeks by home self-infusion and then weekly for the next 8 weeks, concurrent with the blinded oral study drug at the prescribed doses. The primary end points were the change between baseline and week 4 in the tender joint count, erythrocyte sedimentation rate, and urinary excretion of pyridinoline.

RESULTS

The trial was stopped prematurely after enrollment of 31 patients. Three subjects were withdrawn because of worsening arthritis, and 1 patient was withdrawn when newly diagnosed with breast cancer. Infusion-related events occurred in 13 (42%) of 31 patients, but none were serious. There were 4 serious adverse events unrelated to the study drug, including a new diagnosis of breast cancer in 3 cases and hospitalization for abdominal pain in 1 case. No significant differences were observed across treatment groups in any of the 3 primary clinical end points.

CONCLUSION

Although IV doxycycline therapy was generally well-tolerated by patients in this trial, it did not show any evidence of reducing disease activity or collagen crosslink production.

Serum free light-chain measurements for identifying and monitoring patients with nonsecretory multiple myeloma

Using sensitive, automated immunoassays, increased concentrations of either kappa or lambda free light chains (and abnormal kappa/lambda ratios) were detected in the sera of 19 of 28 patients with nonsecretory multiple myeloma. Four other patients had suppression of one or both light chains, and the remaining 5 sera had normal or raised free light-chain concentrations with substantially normal kappa/lambda ratios. Six of the patients with an elevated single free light chain, who were studied during follow-up, had changes in disease activity that were reflected by the changes in free light-chain concentrations. It is concluded that quantification of free light chains in serum should prove useful for the diagnosis and monitoring of many patients with nonsecretory myeloma.

Highly sensitive, automated immunoassay for immunoglobulin free light chains in serum and urine

BACKGROUND

Bence Jones proteins or monoclonal immunoglobulin kappa and lambda free light chains (FLCs) are important markers for identifying and monitoring many patients with B-cell tumors. Automated immunoassays that measure FLCs in urine and serum have considerable clinical potential.

METHODS

Sheep antibodies, specific for FLCs, were prepared by immunization with pure kappa and lambda molecules and then adsorbed extensively against whole immunoglobulins. The antibodies were conjugated onto latex particles and used to assay kappa and lambda FLCs on the Beckman IMMAGE protein analyzer.

RESULTS

The unconjugated antibodies showed minimal cross-reactivity with intact immunoglobulins or other proteins. With latex-conjugated antibodies, kappa and lambda FLCs could be measured in normal sera and most normal urine samples. Patients with multiple myeloma had increased concentrations of the relevant serum FLC, whereas both FLCs were increased in the sera of patients with systemic lupus erythematosus.

CONCLUSIONS

We developed sensitive, automated immunoassays for kappa and lambda FLC measurements in serum and urine that should facilitate the assessment of patients with light chain abnormalities.

Reliability in grading the severity of lumbar spinal stenosis

Stenosis of the lumbar spinal canal is a major cause of disability and lost productivity. Computed tomography (CT) is used commonly to assess the presence and severity of spinal stensosis, because it is relatively inexpensive, readily available, and has few adverse effects. The ability of four surgeons to agree about the presence and severity of lumbar spinal stenosis based on plain CT scans was evaluated from 30 scans of varying stenosis severity (normal to severe). Kappa, a measure of chance-corrected agreement, was calculated. Surgeons exhibited moderate agreement for the presence or absence of spinal stenosis (kappa = 0.58+/-0.06). Agreement regarding the severity of stenosis, when present, was poor (kappa = 0.26+/-0.04). The ability of surgeons to agree was not improved when individual features of the CT scans were assessed (facet joint arthrosis, ligamentum flavum hypertrophy, disk protrusion, and nerve root impingement). This study suggests that CT scans are not a reliable method by which to examine the severity of lumbar spinal stenosis.

Controlling mouse pointer position using an infrared head-operated joystick

This paper describes the motivation for and the design considerations of a low-cost head-operated joystick. The paper briefly summarizes the requirements of head-operated mouse pointer control for people with disabilities before discussing a set of technological approaches that can be used to satisfy these requirements. The paper focuses on the design of a head-operated joystick that uses infrared light emitting diodes (LED's) and photodetectors to determine head position, which is subsequently converted into signals that emulate a Microsoft mouse. There are two significant findings. The first is that, while nonideal device characteristics might appear to make the joystick difficult to use, users naturally compensate for nonlinearities, in a transparent manner, because of visual feedback of mouse pointer position. The second finding, from relatively informal, independent trials, indicates that disabled users prefer a head-operated device that has the characteristics of a joystick (a relative pointing device) to those of a mouse (an absolute pointing device).

Excessive use of vancomycin: a successful intervention strategy at an academic medical center

The project goal was to decrease excessive vancomycin use. Interventions included an educational chart note the first day of therapy, followed by pharmacists discussing the need for continued therapy with patients' physicians. Empirical vancomycin use improved from 20% to 90% compliance with guidelines within 6 months of the intervention.

The impact of counselling on HIV-infected women in Zimbabwe

The objective of this study was to examine the impact of counselling provided for HIV-infected women in Zimbabwe. Qualitative research was used for data collection. In total, 44 women were heard; most were members of an HIV support group. Doctors and nurses play an important role in the first counselling session, because tests to diagnose HIV-infection are done in the hospital. Interviewed women mention slow disclosure of status as the most comforting way to hear the news. The HIV-infected women experience strong emotions directly after diagnosis. Counselling at this moment is of major importance to reduce fear and can prevent suicide. Women should be prevented from discovering their status on their own. Counselling given once is found not to be effective. First, if only one counselling session is given, the women may not hear or remember all that is said. Second, in case of depression, access to counselling is important and it appears that periods of depression return frequently. Support groups play an important role in providing this continuous counselling. Another advantage of the counselling provided by HIV-positive women of a support group is that the counsellors function as examples.

Peroxisome proliferators increase the formation of BPDE-DNA adducts in isolated rat hepatocytes

Peroxisome proliferators are known to modulate the activity of xenobiotic-metabolising enzymes, including glutathione S-transferase (GST) and cytochrome P-450 (CYP). In this study the effect of peroxisome proliferators silvex and di(2-ethylhexyl)phthalate (DEHP) on the formation of (+)-anti-benzo(a)pyrene -7,8-dihydrodiol-9,10-epoxide (BPDE)-DNA adducts from a proximate mutagen and carcinogen (-)-transbenzo(a)pyrene-7,8-dihydrodiol (BPDD) has been investigated. Rat CYP1A1 metabolises BPDD to mutagenic BPDE, which may form DNA adducts or, alternatively, be detoxified by hydrolysis or glutathione conjugation. In this experiment the formation of BPDE-DNA adducts was significantly increased in hepatocytes isolated from all silvex treated rats and two out of four DEHP treated rats (14 day treatment). The activity of CYP1A1 was increased whereas GST was reduced by the peroxisome proliferator silvex. These changes were more significant than those induced by DEHP. We have hypothesised that the formation of BPDE-DNA adducts was primarily due to the increased BPDD activation to BPDE versus reduced detoxication of BPDE. Other hepatic changes induced by the peroxisome proliferators, e.g. peroxisome proliferation per se and increased mitotic activity of the liver could have an effect on the outcome of BPDD exposure.

Perceptions of children and community members concerning the circumstances of orphans in rural Zimbabwe

Focus group discussions and interviews were held with 40 orphans, 25 caretakers and 33 other community workers from a rural area near Mutare, Zimbabwe. Orphan concerns included feeling different from other children, stress, stigmatization, exploitation, schooling, lack of visits and neglect of support responsibilities by relatives. Many community members, while recognizing their limitations due to poverty, were already actively helping orphans and caretakers. Extended family networks are the primary resource for orphans, though some relatives exploit orphans or fail to fulfil their responsibilities. Interventions are suggested which support community coping mechanisms by strengthening the capacities of families to care for orphans. Outside organizations can develop partnerships with community groups, helping them to respond to the impact of AIDS, by building upon existing concern for orphan families. They can help affected communities to develop orphan support activities which encourage caring responses by community leaders and relatives and which discourage property-grabbing and orphan neglect. Material support channelled through community groups to destitute families at critical times can strengthen family coping mechanisms. Income-generating activities should build upon communities' existing capabilities and benefit the most vulnerable orphan households. Some communities are responding to the AIDS disaster by adaptations to cope with devastating changes taking place in their communities.

Peroxisome proliferator nafenopin potentiated cytotoxicity and genotoxicity of cyclophosphamide in the liver and bone marrow cells

Peroxisome proliferators are ubiquitous rodent hepatocarcinogens, known to modulate the activities of xenobiotic-metabolising enzymes such as glutathione S-transferases (GST) and mixed-function oxidase (cytochrome P-450). In addition these compounds induce pleiotropic changes in the liver of rodents even after a short-term treatment. It has been hypothesised that the enzymatic and cellular changes induced by peroxisome proliferators may alter the toxicity of other compounds activated by cytochrome P-450 and detoxified by GST isoenzymes. The effect of nafenopin-induced changes in the liver of rats on the toxicity of an anti-cancer drug cyclophosphamide was studied using cyto- and geno-toxicity parameters in the liver and bone marrow cells. The administration of cyclophosphamide (10 or 20 mg/kg bw) to the rats pre-treated with 80 mg/kg bw of nafenopin for 2 days resulted in significantly increased cytotoxic response in bone marrow cells. However, genotoxicity of cyclophosphamide was increased only in the liver of nafenopin pre-treated rats. Low level of genotoxicity in bone marrow could be accounted for potentiated cytotoxicity of cyclophosphamide. These events coincided with a significant, up to 5-fold, increase in indirect activation-detoxication index for cyclophosphamide, determined as a ratio of ECOD and GST activities, in nafenopin treated rats. This resulted from the induction of ECOD responsible for the formation of reactive metabolites of cyclophosphamide and reduced activity of GST responsible for their detoxication. In addition, mitotic activity of hepatocytes was increased in nafenopin treated rats that might also have an impact on the genotoxicity of cyclophosphamide in this organ.

Differential effect of peroxisome proliferators on rat glutathione S-transferase isoenzymes

We have investigated the effects of peroxisome proliferators silvex, nafenopin and diethylhexylphthalate (DEHP) on rat liver glutathione S-transferase (GST) isoenzyme activities and patterns. Silvex was a more potent in vitro GST inhibitor than nafenopin and DEHP. After 14 days oral administration to rats a reduction in total GST activity was observed, doses of compounds were chosen so that peroxisome proliferation was equivalent between compounds, nevertheless total GST activity was altered to different extents: nafenopin approximately silvex > DEHP approximately control. GST isoenzyme profiles were also altered, the proportion of GST 2-2 increased and 4-4 decreased compared to control levels. The results indicated that: (i) the peroxisome proliferators studied had similar effects on GST isoenzyme profile: (ii) modulation of the GST activity was apparently independent of peroxisome proliferation per se.

Effect of peroxisome proliferator nafenopin on the cytotoxicity of dihaloalkanes in isolated rat hepatocytes

Hepatocytes were isolated from nafenopin-treated animals (80 mg/kg body weight in 1.2 ml/kg body weight olive oil for 2 consecutive days) and exposed to various doses of 1,2 dichloroethane (DCE) (64-159 mumol) and 1,2-dibromoethane (DBE) (5.5-27.5 mumol) for up to 3 hr to assess the effect of nafenopin on the toxicity of dihaloalkanes. The activity of biotransformation enzymes involved in the activation and detoxication of these solvents was measured. Although cytochrome P450IIE1 activity was apparently unaltered, glutathione S-transferase activity was significantly reduced; the reduction was 20% for 1-chloro-2,4-dinitrobenzene as substrate but 40% and 80%, respectively for DBE and DCE. DBE was more than 10 times more cytotoxic to nafenopin-treated hepatocytes than DCE, and while very little change in DCE cytotoxicity was observed in hepatocytes isolated from nafenopin pretreated rats compared with control animals, DBE cytotoxicity was significantly potentiated in cells isolated from nafenopin-pretreated rats compared with cells from controls. It is believed that enhanced toxicity of DBE in isolated cells from nafenopin-treated rats is the result of modulation of dihaloalkane metabolism (glutathione conjugation).

Supporting children in need through a community-based orphan visiting programme

There is an urgent need for programmes to be established to support the growing number of orphans in countries severely affected by AIDS. Most orphans are being cared for by extended families under difficult circumstances. Few descriptions of community-based orphan support programmes exist. We describe one such programme established in Zimbabwe in 1993. Twenty-five volunteers identified 300 orphan households. During one year, volunteers made 1725 home visits and 123 households received an average of $11 in material support or school fees. In 292 orphan households there were 702 orphans, 14.7% of children under 15 years in the area. The rate of parental deaths was increasing with 3.5% of households in the area having a parental death in 1994. Forty-five per cent of caregivers were grandparents and 33% of caregivers were over 60 years. Three per cent of orphans were cared for by adolescent siblings. The poorest orphan households were those in receipt of school fees, with out-of-school children or with an older sibling as caregiver. Community members initiated activities to help orphans. The programme described is targeted, effective and replicable. Community-based organizations such as local churches and women's groups can be mobilized to administer programmes which provide support to the poorest orphan households.

Average speaking fundamental frequency in soprano singers with and without symptoms of vocal attrition

Nineteen trained soprano singers aged 18-30 years vocalized tasks designed to assess average speaking fundamental frequency (SFF) during spontaneous speaking and reading. Vocal range and perceptual characteristics while singing with low intensity and high frequency were also assessed, and subjects completed a survey of vocal habits/symptoms. Recorded signals were digitized prior to being analyzed for SFF using the Kay Computerized Speech Lab program. Subjects were assigned to a normal voice or impaired voice group based on ratings of perceptual tasks and survey results. Data analysis showed group differences in mean SFF, no differences in vocal range, higher mean SFF values for reading than speaking, and 58% ability to perceive speaking in low pitch. The role of speaking in too low pitch as causal for vocal symptoms and need for voice classification differentiation in vocal performance studies are discussed.

Crystal structure of AmiC: the controller of transcription antitermination in the amidase operon of Pseudomonas aeruginosa

The crystal structure for the negative regulator (AmiC) of the amidase operon from Pseudomonas aeruginosa has been solved at a resolution of 2.1 A. AmiC is the amide sensor protein in the amidase operon and regulates the activity of the transcription antitermination factor AmiR, which in turn regulates amidase expression. The AmiC structure consists of two domains with an alternating beta-alpha-beta topology. The two domains are separated by a central cleft and the amide binding site is positioned in this cleft at the interface of the domains. The overall fold for AmiC is extremely similar to that for the leucine-isoleucine-valine binding protein (LivJ) of Escherichia coli despite only 17% sequence identity, however, the two domains of AmiC are substantially closed compared with LivJ. The closed structure of AmiC is stabilized significantly by the bound acetamide, suggesting a molecular mechanism for the process of amide induction. The amide binding site is extremely specific for acetamide and would not allow a closed conformation in the presence of the anti-inducer molecule butyramide.

The effects of ibuprofen enantiomers on hepatocyte intermediary metabolism and mitochondrial respiration

In vivo and in vitro (-)R-ibuprofen is inverted to the (+)S antipode via stereoselective formation of an R-ibuprofenyl-CoA intermediate. In this study the effects of (-)R- and (+)S-ibuprofen on metabolism and respiration were studied using isolated rat hepatocytes and mitochondria. R-Ibuprofen significantly increased the lactate to pyruvate ratio, perturbed mitochondrial ketogenesis as evidenced by alterations in the beta-hydroxybutyrate to acetoacetate ratio and uncoupled mitochondrial oxidative phosphorylation. In addition, substantial dose- and time-dependent sequestration of reduced CoA (CoASH) occurred in the presence of the R enantiomer. Similarly, S-ibuprofen altered both the cytosolic and mitochondrial redox states although the magnitude of the effect was substantially less than that observed with the R enantiomer. In contrast to R-ibuprofen, S-ibuprofen did not uncouple oxidative phosphorylation or sequester hepatocyte CoASH. It is proposed that the perturbations observed in hepatocyte intermediary metabolism and mitochondrial function are attributable to a combination of the direct effects of R-ibuprofen per se and the sequestration of CoASH as R-ibuprofenyl-CoA during the process of chiral inversion. On the basis of these results, R-ibuprofen should be considered more in terms of metabolism to a reactive acyl-CoA intermediate rather than as a pro-drug for the pharmacologically active S-enantiomer.

Cloning and DNA sequence of amiC, a new gene regulating expression of the Pseudomonas aeruginosa aliphatic amidase, and purification of the amiC product

Using in vitro-constructed deletions and subcloned DNA fragments, we have identified a new gene, amiC, which regulates expression of the inducible Pseudomonas aeruginosa aliphatic amidase activity. The DNA sequence of the gene has been determined, and an open reading frame encoding a polypeptide of 385 amino acids (molecular mass, 42,834 Da) has been identified. A search of sequence libraries has failed to find homologies with other published sequences. The amiC translation termination codon (A)TGA overlaps the initiation codon for the downstream amiR transcription antitermination factor gene, implying that the amiCR operon is coordinately regulated. Disruption of the amiC open reading frame by insertion and deletion leads to constitutive amidase synthesis, suggesting that AmiC is a negative regulator. This is confirmed by the finding that a broad-host-range expression vector carrying amiC (pSW41) represses amidase expression in a series of previously characterized P. aeruginosa amidase-constitutive mutants. The AmiC polypeptide has been purified from PAC452(pSW41), and N-terminal amino acid sequencing has confirmed the gene identification.

Ocular injury induced by methyl ethyl ketone peroxide

Methyl ethyl ketone peroxide is a commonly used catalyst in various industries. We studied 19 eyes with a single exposure to methyl ethyl ketone peroxide that developed clinical patterns of mild injury, moderate injury, severe injury, or delayed keratitis. Delayed methyl ethyl ketone peroxide keratitis may cause exacerbations and remissions of corneal and limbal disease lasting more than 20 years with palpebral and bulbar hyperemia equal to the initial chemical exposure. With repeat exacerbation, further pannus may occur, which can be associated with a poorer outcome. Based on the capability of methyl ethyl ketone peroxide to change DNA to a new weak antigen, we suggest possible methods of therapy to prevent or limit delayed methyl ethyl ketone peroxide keratitis. This proposed type of injury has important implications in studying various limbal and corneal diseases. A major factor in the severity of ocular injury was the length of time from exposure to methyl ethyl ketone peroxide to obtaining a topical ocular local anesthetic to perform adequate lavage.

Positive control of Pseudomonas aeruginosa amidase synthesis is mediated by a transcription anti-termination mechanism

The DNA sequence of the region upstream from the amidase structural gene (amiE) of Pseudomonas aeruginosa indicates that amidase (EC 3.5.1.4) is transcribed from an Escherichia coli-like promoter located 150 bp before the amiE translation initiation codon. The sequence between the promoter and the coding sequence includes a single open reading frame followed by an E. coli-like rho-independent transcription terminator. A deletion within the presumed terminator region which disrupts the potential stem/loop formation leads to high constitutive amidase expression which is independent of the product of the regulator gene (amiR). It is proposed that the catabolic aliphatic amidase of P. aeruginosa is regulated by a transcription anti-termination mechanism. The magnoconstitutive mutant PAC433 has promoter and terminator sequences identical to the wild-type PAC1 but contains a single base pair change in the amiE gene ribosome-binding site.

An experiment in enzyme evolution. Studies with Pseudomonas aeruginosa amidase

The regulation of amidase synthesis in P. aeruginosa is under positive control. This review describes the experimental evolution of amidase and its regulator protein for the hydrolysis of novel substrates and experiments to elucidate the mechanism of the control system.

Studies on the expression of Cu,Zn superoxide dismutase in human tissues during development

The developmental expression of Cu,Zn superoxide dismutase in human lung and erythrocytes has been studied using activity measurements, immunoblotting and immunohistochemistry. Enzyme activity in erythrocytes increased significantly during gestation but no developmental trend was seen in lung. Immunoblotting identified a single enzyme form that was present in a variety of tissues and immunohistochemistry showed the enzyme to have widespread distribution in lung tissue. These data indicate that Cu,Zn superoxide dismutase is consistently expressed during human development and that, unlike in other species, no late-fetal surge in expression occurs.

A radioisotopic assay of picomolar concentrations of coenzyme A in liver tissue

A single-step enzyme assay using [14C]palmitic acid and bacterial acyl-coenzyme A synthetase (EC 6.2.1.3) is described for the determination of reduced coenzyme A (CoASH) levels in liver samples. Use of this technique provides a rapid and accurate determination of CoASH in the range 1-250 pmol. Application of the method to the quantitation of CoASH in samples of human liver tissue and rat liver homogenate, isolated hepatocytes, and mitochondria is described.

Studies on the developmental expression of glutathione S-transferase isoenzymes in human heart and diaphragm

The developmental expression of the basic, near-neutral and acidic isoenzymes of glutathione S-transferase (RX:glutathione R-transferase, EC 2.5.1.18) has been studied in heart and diaphragm. Neither these enzymes nor the putative muscle-specific GST4 isoenzyme demonstrated any developmental trends in expression. In vitro hybridisation and SDS-discontinuous polyacrylamide gel electrophoresis were used to show that the GST4 isoenzyme is a homodimer composed of monomers that have a slightly larger molecular weight than the near-neutral isoenzyme. The sensitivity of GST4 to inhibitors also appeared similar to that of the GST1 2 isoenzyme. Immunodiffusion and immunoblotting techniques were used to show that the acidic enzyme in muscle is immunologically identical to that in other tissues.

The amidase regulatory gene (amiR) of Pseudomonas aeruginosa

Recombinant plasmids carrying the amidase genes of Pseudomonas aeruginosa were used to study the genetic control of amidase synthesis in Escherichia coli and Pseudomonas aeruginosa. The amidase regulator gene, amiR, was found to lie about 2 kbp downstream from the structural gene, amiE. Using plasmids with in vitro-constructed deletions, and plasmids containing subcloned DNA fragments, the amiR gene was located within a 1 kbp ClaI-XhoI DNA fragment. The structural and regulator genes were shown to be transcribed in the same direction. Deletion of DNA sequences between the two genes resulted in increased synthesis of amidase in both E. coli and P. aeruginosa. The intervening sequences showed no repressing effect when tested in trans. The results suggested that the amiR gene could be transcribed from more than one promoter.

Haemoglobin A/F ratio in neonates at 7 days correlated with birth weight and estimated gestational age

Haemoglobin (Hb) A and Hb F has been determined in neonates of Afro-Caribbean and North European origin with gestational ages varying from 32 to 42 weeks. There was no difference in the distribution of Hb A/F ratios between the two groups. Only weak correlations could be established between the Hb A/F ratio and the estimated gestational age or birth weight. This would indicate that there is a considerable interindividual variation in the timing of the switching of haemoglobin synthesis from Hb F to Hb A and erythrocyte production from liver to bone marrow and of oxygen affinity of fetal blood. Thus, intra-uterine adjustments of the oxygen release capacity of haemoglobin would have to rest on biochemical mechanisms during the third trimester.

Interaction of benoxaprofen with rat erythrocytes: effects on oxidative metabolism and membrane ATPase activities

Incubation of rat erythrocytes with benoxaprofen resulted in increased glucose utilization, lactate production, depletion of cellular ATP and significant haemolysis. In isolated red cell membranes, benoxaprofen produced a dose related stimulation of both Ca2+ dependent and Ca2+ independent ATPase activities. Coincubation of either erythrocytes or red cell membranes with cysteine ameliorated the effects of benoxaprofen. A possible association exists between the mechanism of the reported anti-inflammatory activity of benoxaprofen and its cellular toxicity.