Cutaneous wound analysis using hyperspectral imaging

A correlative bright-field and hyperspectral analysis of full-thickness, cutaneous wounds in a porcine model was undertaken to investigate the efficacy of hyperspectral imaging as an alternate method for wound identification. Analysis of a randomly selected specimen yielded distinct spectral signatures for cutaneous regions of interest including the epidermis, injured dermis, and normal dermis. The scanning of the entire specimen group using these hyperspectral signatures revealed an exclusionary, pseudo-color pattern whereby a central wound region was consistently defined by a unique spectral signature. An algorithm was derived as an objective tool for the comparison of the wound regions defined by the hyperspectral classification versus the pathologists' manual tracings. The dimensions of the wound identified in the hyperspectral assay did not differ significantly from the wound region identified by the pathologists using standard bright-field microscopy. These data indicate that hyperspectral analysis may provide a high-throughput alternative for wound estimation that approximates standard bright-field imaging and pathologist evaluation.

The duPont kyphosis brace for the treatment of adolescent Scheuermann kyphosis

The purpose of this study was to evaluate the effectiveness of a newly designed brace in the treatment of adolescent Scheuermann thoracic kyphosis. Twenty-two children who met the roentgenographic criteria of Scheuermann kyphosis and were compliant with treatment were followed until skeletal maturity. Sixteen patients (73%) showed nonprogression of their kyphosis (nine patients demonstrated an improvement, seven patients remained unchanged), and had a mean improvement of 9 degrees (64 degrees to 55 degrees). Six patients (27%) demonstrated progression of the kyphosis and had a mean increase in their kyphosis of 9 degrees (59 degrees to 68 degrees). One patient underwent posterior spinal fusion for progressive thoracic kyphosis despite bracing. It was recommended that this brace be worn until skeletal maturity; in this study this time period was determined to be at least 16 months to induce improvement or halt progression of this disease. Flexible curves are a positive predictor of a successful outcome of bracing with the kyphosis brace. These results are comparable to previous reports in the literature describing the effectiveness of the modified Milwaukee brace in the treatment of Scheuermann thoracic kyphosis prior to skeletal maturity, and the kyphosis brace has the advantage of concealability under normal attire.

Methemoglobinemia induced by topical benzocaine: a warning for the endoscopist

Benzocaine is used routinely for topical pharyngeal anesthesia prior to upper endoscopy, to improve patient tolerance. A potentially fatal, although often unrecognized, complication of benzocaine use is methemoglobinemia. Here, we report a case of methemoglobinemia induced by benzocaine given before upper endoscopy. Rapid recognition of this complication and immediate treatment is essential to prevent complications related to significant tissue hypoxia. This case serves as an important reminder to physicians, especially endoscopists, about this serious side effect. Furthermore, we question the need for topical anesthesia for upper endoscopy in sedated patients.

The effect of a 5-day space flight on the immature rat spine

BACKGROUND CONTEXT

Spaceflight has many reported effects upon the musculoskeletal system structure and function. This study was designed to determine the effect of a 5-day flight on the rat spine.

METHODS

In September 1991, 8 neonatal rats were flown aboard the Space Shuttle Columbia flight STS-48 during a 5-day mission. Upon return to earth, the spines were dissected, frozen and shipped to our laboratory. Matched ground-based rats were used as controls. The spines were radiographed and then slowly thawed. Individual vertebrae were subjected to compressive biomechanical testing using an Instron tester (Instron Corp, Canton, MA, USA) and then processed for determination of calcium and phosphorus content. The intervertebral discs were placed in physiological saline and the stress-relaxation characteristics measured. The discs were then lyophilized and assayed for collagen and proteoglycan content. Disc height on radiographs was measured by image analysis.

RESULTS

After space flight, the heights of the discs were found to be 150 to 200 microns greater, although the values were not statistically significant. There was no difference in the resiliency of the thoracic discs as determined by stress-relaxation. However, in the lumbar discs, space flight increased the resiliency (p<.01). There was no difference in water content. In both the thoracic and lumbar discs there was a 3.3-fold increase in hydroxyproline-proteoglycan ratio after space flight. However, because of the small sample size, these values were not statistically significant. In the vertebrae, there was no difference in calcium-phosphate ratio or compressive strength.

CONCLUSIONS

These data suggest that even after a short 5-day flight, the spine begins to undergo biomechanical and biochemical changes. In addition, the weightless environment in space may provide a good model to study the effects of immobilization on earth.

PI-3' kinase and NF-kappaB cross-signaling in human pancreatic cancer cells

Because tumor necrosis factor-alpha (TNF-alpha) and some chemotherapeutic agents activate both apoptosis and NF-kappaB-dependent antiapoptotic genes, they may neutralize their own antitumor effects. The cell-signaling mechanisms for such chemoresistance are not clear but may involve phosphotidylinositol-3' kinase (PI3K). To clarify this we examined whether cross-signaling between PI3K and NF-kappaB enhances the antitumor effect of TNF-alpha in human pancreatic cancer cells. Quiescent pancreatic cancer cells (Panc-1, MiaPaCa-2) with TNF-alpha, Ly294002 (PI3K inhibitor), alone or combined, were restimulated with mitogen (10% fetal calf serum [FCS] to induce cell cycle entry). Proliferation (monotetrazolium), cell cycle progression (ApoBrDU and fluorescence-activated cell sorter analysis), and apoptosis (PARP cleavage; caspase-3 activation) were measured. Akt activation (Akt kinase assay) and IkappaBalpha degradation were determined by Western blot analysis. Translocation of NF-kappaB into the nucleus was examined by EMSA, whereas an NF-kappaB/luciferase reporter gene was used to quantify NF-kappaB-dependent gene expression. Statistical analysis was carried out by means of two-tailed t test (P <0.05). PI3K inhibition significantly enhanced the antiproliferative and proapoptotic effects of TNF-alpha in both cell lines, Ly294002 also blocked TNF-alpha-induced Akt activation but failed to alter cytoplasmic IkappaBalpha degradation or subsequent NF-kappaB nuclear translocation. NF-kappaB-dependent gene expression, however, was ultimately suppressed by Ly294002, suggesting that PI3k-dependent activation of NF-kappaB is IkappaBalpha independent. PI3K inhibition can block NF-kappaB-dependent gene expression regardless of cytoplasmic IkappaBalpha/NF-kappaB activation. Because it also regulates the antitumor effects of TNF-alpha, PI3K may in part determine NF-kappaB-induced chemoresistance in human pancreatic cancer.

Simultaneous determination of losartan and hydrochlorothiazide in combined dosage forms by first-derivative spectroscopy and high-performance thin-layer chromatography

Losartan (LST) is the first orally active nonpeptide angiotensin-II receptor antagonist with an improved safety and tolerability profile. It is prescribed alone or in combination with hydrochlorothiazide (HCTZ) for the treatment of moderate-to-severe hypertension. This paper describes the development of 2 methods that use different techniques, first-derivative spectroscopy and high-performance thin-layer chromatography (HPTLC), to determine LST and HCTZ in the presence of each other. LST and HCTZ in combined preparations were quantitated by using the first-derivative responses at 271.6 nm for LST and 335.0 nm for HCTZ in spectra of their solutions in water. The linearity ranges are 30-70 microg/mL for LST and 7.5-17.5 microg/mL for HCTZ with correlation coefficients of 0.9998 and 0.9997, respectively. In the HPTLC method, a mobile phase of chloroform-methanol-acetone-formic acid (7.5 + 1.5 + 0.5 + 0.03, v/v) and a prewashed Silica Gel G60 F254 TLC plate as the stationary phase were used to resolve LST and HCTZ in a mixture. Two well-separated and sharp peaks for LST and HCTZ were obtained at Rf values of 0.61+/-0.02 and 0.41+/-0.02, respectively. LST and HCTZ were quantitated at 254.0 nm. The linearity ranges obtained for the HPTLC method are 400-1200 and 100-300 ng/spot with corresponding correlation coefficients of 0.9944 and 0.9979, for LST and HCTZ, respectively. Both methods were validated, and the results were compared statistically. They were found to be accurate, specific, and reproducible. The methods were successfully applied to the estimation of LST and HCTZ in combined tablet formulations.

Impaired bioavailability of rifampicin in presence of isoniazid from fixed dose combination (FDC) formulation

The present study describes comparative bioavailability of rifampicin (RIF) after administration of a single component RIF (450 mg) capsule and rifampicin-isoniazid (RIF-INH) (450+300 mg) fixed dose combination (FDC) capsule formulations. Six healthy male volunteers participated in a single dose, two treatment, two period, cross-over study. A sensitive, specific and accurate HPTLC method was developed, validated and employed for estimation of RIF and its major active metabolite, 25-Desacetylrifampicin (25-DAR) levels, in urine. Using the urinary excretion data various pharmacokinetic parameters: AUC(0-24), AUC(0-infinity), cumulative amount excreted in 24 h, peak excretion rate, etc. for both RIF and 25-DAR were calculated and compared statistically (ANOVA, 90% confidence interval for ratio). Significant decrease in the bioavailability ( approximately 32% as RIF and approximately 28% as 25-DAR) of RIF from FDC capsules was observed. The present bioavailability study confirms our serious doubts about the stability of RIF in presence of INH in acidic environment of stomach, which probably is the main factor responsible for the reduced bioavailability of RIF from RIF-INH combination formulations. This study underlines the fact that there is an urgent need to reconsider the formulation of the FDC product in order to minimize or avoid the decomposition of RIF in gastrointestinal tract.

Molecular genetics of ulcerative colitis-associated colon cancer in the interleukin 2- and beta(2)-microglobulin-deficient mouse

Mice deficient in beta(2)-microglobulin and interleukin 2 (beta(2)m(null) x IL-2(null)) spontaneously develop colon cancer in the setting of chronic ulcerative colitis (UC). We investigated mutations of the Apc and p53 genes and microsatellite instability in colonic adenocarcinomas arising in this model. Mutations of the Apc and p53 genes in the regions corresponding to mutation hot spots in human colorectal cancer were determined by sequencing in 11 colonic adenocarcinomas. Microsatellite instability was determined in matched normal and neoplastic DNA at five loci. All 11 adenocarcinomas harbored Apc mutations. Of these 11 tumors, 5 harbored truncating mutations. A total of 67 Apc mutations were found in these 11 tumors; 59 were missense mutations, whereas 8 were frameshift or nonsense mutations. Six of the 11 adenocarcinomas harbored p53 mutations. A total of seven p53 mutations were found in these 11 tumors; all mutations were transitions, 4 of which were C:G-->T:A transitions occurring in codon 229 at cytosine-guanine dinucleotides. Nine adenocarcinomas exhibited microsatellite instability in at least one of the five loci examined; 1 tumor had microsatellite instability in two loci. Molecular genetics, as well as clinical features, of colon cancer in the beta(2)m(null) x IL-2(null) mice are similar to those of human UC-associated colorectal cancer. As such, this model appears to be an excellent animal model to study UC-associated colorectal carcinogenesis.

Protective effects of ischemic preconditioning on the cold-preserved liver are tyrosine kinase dependent

BACKGROUND

Little data exist regarding the use of ischemic preconditioning before sustained hepatic cold storage. We hypothesized that ischemic preconditioning protects hepatic grafts via a tyrosine kinase-dependent pathway.

METHODS

Six porcine livers underwent routine harvest (control). Five other livers underwent 15 min of in situ ischemia followed by 15 min of reflow before harvest (ischemic preconditioning). Another five livers were pretreated with a tyrosine kinase inhibitor (genistein) before preconditioning. Upon reperfusion and after 2 hours of cold storage, graft function, graft circulatory impairment, and markers of cellular damage were analyzed. Tissue cytoplasmic extracts were analyzed for tyrosine phosphorylation with Western blot. Significance was determined with t tests.

RESULTS

Ischemic-preconditioned grafts demonstrated enhanced bile production, augmented responses to a bile acid challenge, and elevated O2 consumption (P<0.05) compared to controls. Also, preconditioned grafts demonstrated improved hepatic tissue blood flow and decreased hepatic vascular resistance (P<0.005) compared to controls. Endothelial cell preservation (factor VIII immunostain) was improved in preconditioned graft biopsies compared to controls. With genistein pretreatment, all observed improvements returned to control levels. Analysis of cytoplasmic extracts demonstrated an increase in tyrosine phosphorylation before cold ischemia in preconditioned grafts only, but not in control or genistein-pretreated grafts.

CONCLUSIONS

The data indicate that ischemic preconditioning protects the liver from sustained cold ischemia and that tyrosine kinases are involved in preconditioning responses.

A critical appraisal of laparoscopic staging in hepatobiliary and pancreatic malignancy

Prognosis for patients with hepatobiliary and pancreatic cancers is dismal. Surgery is the best therapeutic option for those with tumors which have not yet metastasized. Standard radiologic tests such as computed tomography (CT) scan and trans-abdominal ultrasound are useful in identifying patients for whom an attempt at resection would be futile. Staging laparoscopy with laparoscopic ultrasound allows greater precision in identifying those for whom resection would be helpful with less morbidity than an open exploration. Metastatic disease can be identified more precisely than with radiologic tests and can be characterized by biopsy techniques. Palliative procedures are now being performed laparoscopically with low morbidity and short hospital stays. The use of laparoscopy prior to open exploration for patients with hepatobiliary and pancreatic tumors is advantageous.

Ubiquitin proteasome pathway: implications and advances in cancer therapy

The degradation of most eukaryotic cells is controlled by the ubiquitin proteasome pathway. This pathway is responsible not only for the degradation of short and long-lived proteins but also tumor suppressors, transcription factors and cell cycle proteins. Altered degradation of these proteins is thought to promote cancer growth and spread. By contrast, inhibition of the proteasome would lead to cell cycle arrest and ultimately programmed cell death, or apoptosis. A structured review of the published literature examining the role of ubiquitin proteasome inhibition in cancer growth and regulation is provided. Advances in the development of proteasome inhibitors have allowed detailed investigation of this pathway in cancer growth. Relevant in vitro and in vivo studies of proteasome inhibition as pertains to cancer therapy are detailed. The ubiquitin proteasome pathway is critical in the degradation of proteins involved in cell cycle control and tumor growth. Proteasome inhibitors have been shown to arrest or retard cancer progression, by interfering with the ordered, temporal degradation of regulatory molecules. Clinical trials examining the agents have begun.

Bosentan, an endothelin antagonist, augments hepatic graft function by reducing graft circulatory impairment following ischemia/reperfusion injury

Endothelin is a potent hepatic vasoconstrictor. We evaluated the role of an endothelin antagonist in hepatic ischemia/reperfusion injury. Bosentan, a novel endothelin receptor antagonist, was infused directly into the portal vein prior to cold ischemia and immediately on reperfusion, in five porcine livers. Five other pigs underwent routine liver harvest and reperfusion without bosentan treatment. Hepatic vascular resistance and liver tissue blood flow, as measured by thermistor flow probes, were determined following reperfusion. Hepatocellular damage was assessed through hepatic venous levels of sorbitol dehydrogenase and lactate dehydrogenase. Endothelial cell damage was determined in sections immuno-stained for factor VIII. Graft function was determined through oxygen consumption, bile production, and response to bile acid challenge. Organs treated with bosentan demonstrated lower vascular resistance and enhanced tissue blood flow (P < 0.05) as compared to untreated organs. Portal vein inflow to hepatic tissue was significantly enhanced (4.4-fold) in the bosentan-treated organs (P < 0.05). No difference was observed in hepatocellular damage. Pathology scores for factor VIII immunohistochemical staining were 2.3-fold higher in the bosentan-treated livers as compared to untreated livers (P < 0.05). The bosentan-treated livers also demonstrated enhanced oxygen consumption, increased bile production, and augmented biliary response to a bile acid challenge (P < 0.05). These results indicate that administration of bosentan before and after ischemia/reperfusion reduces hepatic circulatory disturbances, diminishes endothelial cell damage, and augments hepatic graft function.

FRAP-p70s6K signaling is required for pancreatic cancer cell proliferation

BACKGROUND

FRAP-p70s6K signaling regulates mitogenic responses to growth factors in eukaryotic cells. Constitutive p70s6K activation occurs in some human malignancies and may contribute to dysregulated cell growth. We examined whether inhibition of this pathway affects mitogen-induced proliferation and cell cycle progression of human pancreatic cancer cells in vitro.

METHODS

Quiescent BxPC3 and Panc-1 human pancreatic cancer cells treated with or without 20 ng/mL rapamycin (FRAP inhibitor) were repleted with 10% FCS to induce cell cycle entry. Proliferation was measured with MTT assay. Cell cycle and apoptosis were determined by FACS analysis. Phosphorylation of p70s6K, Akt, and cdc2 was evaluated by Western blot. Statistical analysis was by two-tailed t test (P < 0.05).

RESULTS

Rapamycin (Rapa) inhibited the phosphorylation of p70s6K while inducing G(1) cell cycle arrest (P < 0.005). In both cell lines, Rapa inhibited serum-induced proliferation (P < 0.05) without affecting apoptosis. Cdc2 phosphorylation was inhibited by 15 min with Rapa (not shown), consistent with cell cycle arrest. Akt phosphorylation was not affected, indicating FRAP specificity of Rapa.

CONCLUSIONS

FRAP-p70s6K signaling appears to be necessary for G(1)-to-S phase progression and proliferation in pancreatic cancer cells. This supports earlier work demonstrating a similar regulatory role for PI-3' kinase, an upstream activator of FRAP-p70s6K.

Protein kinase C inhibition abrogates hepatic ischemic preconditioning responses

INTRODUCTION

A transient period of warm ischemia prior to a longer ischemic episode (ischemic preconditioning) protects the hepatic graft from cold ischemia. The mechanism for this protection is unknown, as is the role of protein kinase C in ischemic preconditioning responses.

METHODS

Livers from 40 kg Yorkshire pigs were harvested and subjected to 2 h of cold ischemia (n = 6) (control). Another group of harvested livers was pretreated with a 15-min ischemic period followed by 15 min of in situ perfusion with (n = 5) or without (n = 5) a protein kinase C inhibitor, chelerythrine. Following cold ischemia, all grafts were reperfused on a perfusion circuit and the following variables evaluated: (1) hepatic graft function, (2) graft circulatory impairment, (3) hepatocellular damage, and (4) endothelial cell damage. Protein kinase C levels were also evaluated by Western blot in the cytoplasm of all grafts.

RESULTS AND DISCUSSION

Ischemic preconditioned grafts demonstrate improved graft function, reduced graft circulatory impairment, and reduced endothelial cell damage as compared to cold ischemia controls. When preconditioned grafts were pretreated with chelerythrine, graft function, graft circulatory impairment, and endothelial cell damage were no different than cold ischemia controls. Ischemic preconditioned grafts demonstrated decreased levels of protein kinase C prior to cold ischemia. There was no change in protein kinase C levels in cold ischemia controls or chelerythrine-pretreated grafts prior to cold ischemia. These data indicate that modulation of protein kinase C is essential for ischemic preconditioning responses in the cold preserved hepatic graft.

Endotoxin (LPS) stimulates 4E-BP1/PHAS-I phosphorylation in macrophages

INTRODUCTION

Translational control of cytokine production in endotoxin (LPS)-stimulated macrophages is poorly characterized but likely important. An early step in protein translation is engagement of mRNA by eukaryotic initiation factor 4E (eIF-4E). Translation initiation can be prevented by small 4E-binding proteins (4E-BP1 or PHAS-I) which must be phosphorylated in order to disengage eIF-4E. We examined whether LPS alters 4E-BP1 phosphorylation in macrophages.

MATERIALS AND METHODS

Elicited rat peritoneal macrophages and Raw 264.7 macrophages were treated with signal transduction inhibitors and then LPS. Cells were harvested and equal protein amounts were electrophoresed (SDS-PAGE). Western blots (WB) were developed with 4E-BP1 antibody. Alternatively cell lysates were exposed to 7-methyl GTP Sepharose beads in order to isolate the cap-binding protein eIF-4E. The relative amounts of 4E-BP1 associated with eIF-4E were then determined by WB.

RESULTS

Macrophage 4E-BP1 is phosphorylated upon stimulation by LPS as evidenced by the appearance of a more slowly migrating gamma (hyperphosphorylated) band on gel electrophoresis. Inhibition of both the p42/p44 MAPK pathway (PD 98059) and the p38 MAPK pathway (SB 203580) failed to alter LPS-induced 4E-BP1 phosphorylation. Rapamycin (FRAP/mTOR inhibitor) blocked 4E-BP1 phosphorylation causing a predominance of the alpha (hypophosphorylated) band. This was confirmed further by 7-methyl-GTP Sepharose isolation of eIF-4E with which 4E-BP1 coprecipitates.

CONCLUSION

LPS stimulates 4E-BP1 phosphorylation in macrophages through FRAP/mTOR signaling. This pathway may contribute to the translational control of cytokine gene expression in macrophages.

26S proteasome inhibition induces apoptosis and limits growth of human pancreatic cancer

The 26S proteasome degrades proteins that regulate transcription factor activation, cell cycle progression, and apoptosis. In cancer, this may allow for uncontrolled cell division, promoting tumor growth, and spread. We examined whether selective inhibition of the 26S proteasome with PS-341, a dipeptide boronic acid analogue, would block proliferation and induce apoptosis in human pancreatic cancer. Proteasome inhibition significantly blocked mitogen (FCS) induced proliferation of BxPC3 human pancreatic cancer cells in vitro, while arresting cell cycle progression and inducing apoptosis by 24 h. Accumulation of p21(Cip1-Waf-1), a cyclin dependent kinase (CDK) inhibitor normally degraded by the 26S proteasome, occurred by 3 h and correlated with cell cycle arrest. When BxPC3 pancreatic cancer xenografts were established in athymic nu/nu mice, weekly administration of 1 mg/kg PS-341 significantly inhibited tumor growth. Both cellular apoptosis and p21(Cip1-Waf-1) protein levels were increased in PS-341 treated xenografts. Inhibition of tumor xenograft growth was greatest (89%) when PS-341 was combined with the tumoricidal agent CPT-11. Combined CPT-11/PS-341 therapy, but not single agent therapy, yielded highly apoptotic tumors, significantly inhibited tumor cell proliferation, and blocked NF-kappaB activation indicating this systemic therapy was effective at the cancer cell level. 26S proteasome inhibition may represent a new therapeutic approach against this highly resistant and lethal malignancy.

Increased urinary nitrite, a marker of nitric oxide, in active inflammatory bowel disease

BACKGROUND

Nitric oxide (NO) production is increased in inflammatory bowel disease (IBD), and measurement of NO metabolites may be useful for monitoring disease activity.

AIMS AND OBJECTIVES

To characterise urinary nitrite levels, a stable metabolite of NO, in IBD and to evaluate its potential as a marker of disease activity.

METHODS

Twelve-hour urinary nitrites were measured by the microplate assay method in 46 patients with IBD (active; n = 32). Urinary samples from 16 healthy individuals served as controls.

RESULTS

Increased levels of urinary nitrites were found in patients with active IBD compared with those with inactive IBD. Twenty-eight out of 32 patients (87.5%) with active IBD had detectable levels of nitrite in their urine as compared with 2/14 (14.3%) patients with inactive IBD. None of the 16 healthy controls had detectable urinary nitrite. Twelve-hour urinary nitrite in active compared with inactive IBD: 5 0.7 versus 0.1+/-0.04 micromol (P < 0.05). There was good correlation between urinary nitrite and some markers of disease activity in IBD such as C-reactive protein and microalbuminuria but not with erythrocyte sedimentation rate.

CONCLUSIONS

Increased levels of nitrite were detected in urine of patients with active IBD, consistent with increased NO synthesis. This simple assay may be exploited as a potential marker of disease activity in IBD.

Hippocampal abnormalities in depression

A quantitative magnetic resonance imaging study of regional brain T1 spin-lattice relaxation times in 29 normal volunteers and in 20 patients with major depression revealed significantly shortened T1 relaxation times for the hippocampus in depressed patients. These differences were particularly prominent in elderly depressed patients. T1 relaxation times are reflective of the content and macromolecular environment of tissue water protons; shorter hippocampal T1 values may reflect differences in the content or organizational properties of hippocampal water protons. These findings are consistent with several lines of evidence that have implicated a role for the hippocampus in the regulation of mood and in the pathophysiology of the stress response, and they suggest that major depression may be associated with biophysical tissue changes in the aging hippocampus.

Aging of the human corpus callosum: magnetic resonance imaging in normal volunteers

A brain magnetic resonance imaging (MRI) study of the corpus callosum in 36 normal volunteers, ages 26-79 years, revealed that age was positively correlated with the T1 spin-lattice relaxation time of the corpus callosum and was negatively correlated with the corpus callosum cross-sectional area. T1 relaxation times are sensitive to the content and macromolecular environment of tissue water, and variations in callosal T1 may reflect differences in the content or relaxation properties of callosal water. Such changes also potentially could occur secondary to alterations in the composition of callosal myelin. This study confirms and extends prior morphological studies that have reported age-related dimensional changes in the corpus callosum and, in addition, provides evidence of age-related biophysical tissue differences in the human corpus callosum.

Clinical experience with infliximab therapy in 100 patients with Crohn's disease

OBJECTIVE

The aim of this study was to assess our clinical experience with infliximab, a monoclonal antitumor necrosis factor antibody, following its approval for treatment of refractory Crohn's disease (CD).

METHODS

We followed 100 consecutive patients with CD (53 women and 47 men; mean age, 41 yr) who received a total of 233 infliximab (5 mg/kg) infusions. Adverse events were noted and clinical response assessed every 2 wk for 6 months after each infusion using the Harvey Bradshaw Index (HBI) for active disease, the Perianal Disease Activity Index (PDAI) for fistulous disease, and steroid withdrawal rates for steroid-sparing efficacy.

RESULTS

Indications for therapy were active disease (n = 57), perianal fistulous disease (n = 33), and steroid dependency (n = 10). Significant infusion reactions occurred in 16 patients (6.9% of infusions) including anaphylactic shock in one patient. Fourteen patients experienced infectious adverse events, 13 of whom were on concurrent steroids. Sixty percent of patients with active disease experienced > or = 50% HBI reduction at 2 wk; mean duration of response, 8.2 wk. Three of 26 first-time nonresponders with active disease (12%) responded to a second infusion. Sixty-nine percent of patients with fistulous disease experienced >50% reduction in their PDAI at 2 wk; mean duration of response, 10.9 wk. Four of 10 steroid-dependent patients (40%) discontinued steroid therapy, one of whom recommenced steroid therapy at 24 wk.

CONCLUSIONS

Our clinical response rates mirror the efficacy reported in the controlled trials for active and fistulous disease. Steroid-sparing efficacy was seen in 40% of steroid-dependent patients. Concurrent steroids did not reduce the risk of significant infusion reactions (6.9%), but did increase the risk of infections.

Evaluation of blood bank practices in Karachi, Pakistan, and the government's response

BACKGROUND

National legislation in Pakistan regulating blood banks has been introduced several times, but has never been passed. To support provincial-level efforts to develop legislation we conducted a study to evaluate blood-banking practices in Karachi, Pakistan, to identify areas that could be improved.

METHODS

Thirty-seven blood banks were randomly selected from a list of 87 Karachi blood banks. The research team interviewed blood bank personnel, inspected available facilities and equipment, and observed blood collection using structured questionnaires and observation forms.

RESULTS

Of the 37 selected facilities, 25 were operational and 24 agreed to participate. Twelve (50%) of the facilities reported regularly utilizing paid blood donors, while only six (25%) activity recruited volunteer donors. During observation only 8% of facilities asked donors about injecting drug use, and none asked donors any questions about high-risk sexual behaviour. While 95% of blood banks had appropriate equipment and reagents to screen for hepatitis B, only 55% could screen for HIV and 23% for hepatitis C. Twenty-nine percent of the facilities were storing blood products outside the WHO recommended temperature limits.

IMPLICATIONS

Practices at most Karachi blood banks fell well below WHO standards. Findings from this study were instrumental in developing and passing legislation to regulate blood transfusion throughout Sindh Province, and suggest a method for improving blood transfusion practices in other developing countries.

Treatment of psoriasis with topical NG-monomethyl-L-arginine, an inhibitor of nitric oxide synthesis

A double blind left, right comparative study was carried out in 17 psoriatic subjects to examine the influence of a topically applied inhibitor of nitric oxide (NO) synthesis on the pathogenic events of psoriasis. The inhibitor NG-monomethyl-L-arginine (L-NMMA) in aqueous cream BP was applied to one plaque while aqueous cream BP alone served as control. Compared with the control, the L-NMMA-treated side showed significant (77%) inhibition of NO production and a reduction in blood flow, confirming its bioavailability. L-NMMA significantly reduced staining for endothelial cells and intercellular adhesion molecule 1, while CD1a-positive Langerhans cells and CD8-positive suppressor cytotoxic T cells increased. CD4-positive lymphocytes and epidermal proliferation, as indicated by Ki-67 staining, were unaffected by this degree of inhibition of NO synthesis, and correspondingly significant clinical improvement was not found.

Dermatitis herpetiformis effectively treated with heparin, tetracycline and nicotinamide

We report a patient with severe dermatitis herpetiformis (DH) who was intolerant of dapsone, sulphapyridine, systemic steroids, and azathioprine. He was treated effectively with a combination of heparin, tetracycline and nicotinamide.

Estimation of individual sennosides in plant materials and marketed formulations by an HPTLC method

Senna is a well-known drug, used in the Ayurvedic and Allopathic systems of medicine, and is a treatment for constipation. The purgative action of senna and its formulations is due to the presence of sennosides A and B. An HPTLC method has been developed for the determination of individual sennosides (A, B, C, D) without any derivatization in marketed formulations (three tablet formulations, two granule formulations and one liquid formulation) and plant materials (senna leaf and pod). The methanolic solution of a sample was applied on a pre-coated silica gel G60 F254 TLC plate (E. Merck.) and was developed using n-propanol : ethyl acetate : water : glacial acetic acid (3 : 3 : 2 : 0.1 v/v) as the mobile phase. The relative band speeds (Rf values) obtained were 0.35, 0.25, 0.61, 0.46 for sennosides A, B, C and D, respectively. The densitometric response was monitored at 366nm. Calibration curves were found to be linear in the concentration ranges 193-1356, 402-2817, 71-497 and 132-927 ng per spot for sennosides A, B, C, and D, respectively. The correlation coefficients were found to be 0.9978, 0.9987, 0.9939 and 0.9983 respectively for sennosides A, B, C and D. The result obtained with the HPTLC method for total sennoside content was compared with the results using the pharmacopoeial methods (spectrophotometric (British Pharmacopoeia) and spectrofluorimetric (United States Pharmacopeia) using the 'F' test). The results revealed no significant difference in the three different methods for estimation of total sennoside. The proposed HPTLC method was found to be simple, specific, precise, accurate and rapid. It can be used for routine quality control of sennosides or senna-containing formulations for individual sennosides.

Non-Boltzmann thermodynamic integration (NBTI) for macromolecular systems: relative free energy of binding of trypsin to benzamidine and benzylamine

The relative free energies of binding of trypsin to two amine inhibitors, benzamidine (BZD) and benzylamine (BZA), were calculated using non-Boltzmann thermodynamic integration (NBTI). Comparison of the simulations with the crystal structures of both complexes, trypsin-BZD and trypsin-BZA, shows that NBTI simulations better sample conformational space relative to thermodynamic integration (TI) simulations. The relative binding free energy calculated using NBTI was much closer to the experimentally determined value than that obtained using TI. The error in the TI simulation was found to be primarily due to incorrect sampling of BZA's conformation in the binding pocket. In contrast, NBTI produces a smooth mutation from BZD to BZA using a surrogate potential, resulting in a much closer agreement between the inhibitors' conformations and the omit electron density maps. This superior agreement between experiment and simulation, of both relative binding free energy differences and conformational sampling, demonstrates NBTI's usefulness for free energy calculations in macromolecular simulations.

Molluscum contagiosum effectively treated with a topical acidified nitrite, nitric oxide liberating cream

A double-blind, group-sequential clinical trial of acidified nitrite was performed to demonstrate the efficacy of this nitric oxide donor in treating molluscum contagiosum. Subjects received either 5% sodium nitrite co-applied with 5% salicylic acid under occlusion, or identical cream with 5% salicylic acid, omitting sodium nitrite. Active and control treatment groups were well matched for the number and duration of lesions and made a similar number of applications. We found a 75% cure rate in the active treatment group and 21% cure with control treatment (P = 0.01). The mean time to cure was 1.83 months. Staining of the skin and irritation were frequent side-effects but did not prevent successful treatment.

HIV-infected workers deported from the Gulf States: impact on Southern Pakistan

HIV prevalence is still very low in Pakistan, but its south Asian location and subgroups with recognized lifestyle risk factors suggest that Pakistan will experience expanded diffusion of HIV. We report the frequency of HIV infections identified by the AIDS Control Programme on the Sindh province of Pakistan. Most HIV-positive cases currently reported to the Sindh AIDS Control Programme are found among Pakistani workers deported from the Gulf States and among foreigners. The 58 returned workers with HIV represent 61 to 86% of reported cases in any given year during the 1996-1998 period. Five wives of returning workers have been identified with HIV. Expatriate workers in the Gulf States are tested for HIV routinely, unlike other subgroups in Pakistan. Considering the risk of HIV/AIDS due to regular introduction of HIV from returned workers, and the limited awareness surrounding sexual health and HIV/STD transmission issues in Pakistan, intervention programmes targeted at overseas workers need to be implemented to control the expansion of the HIV epidemic in Pakistan.

Household members of hepatitis C virus-infected people in Hafizabad, Pakistan: infection by injections from health care providers

Household members of people with hepatitis C are at increased risk of HCV infection. The prevalence and routes of transmission of HCV to household members in Hafizabad, Pakistan were investigated. Household members of 24 index cases were given a risk factor questionnaire, tested for HCV infection, and the risk factors between the infected and uninfected were compared. Twelve of 74 household members (16.2%) were seropositive for HCV antibody. This was 2(1/2) times the rate of infection in the general population (OR = 2.8; P = 0.01). None of the routes of transmission studied within the household was associated with an increased risk. Household members who received more than 4 injections per year were 11.9 times more likely to be infected than those who had not (P = 0.016). In Hafizabad, the greatest risk for HCV infection to household members of infected people is injections given by health-care workers rather than household contact with infected persons.

Stability of rifampicin in dissolution medium in presence of isoniazid

Rifampicin (RIF) hydrolyzes in acidic medium to form insoluble and poorly absorbed 3-Formyl rifamycin SV (3-FRSV). This study describes development of two principally different methods, Dual Wavelength UV-Vis. spectrophotometry (DW spectrophotometry) and HPTLC, to determine 3-FRSV in presence of RIF. Using DW spectrophotometry, RIF was estimated by using wavelengths 475.0 and 507.0 nm and 3-FRSV was estimated using 457.0 and 492.0 nm. In HPTLC method, a mixture of chloroform:methanol:water (80:20:2.5 v/v) was used as the mobile phase to resolve 3-FRSV from RIF and 3-FRSV was quantified at 333 nm. The linearity range for 3-FRSV was 2-10 microg/ml and 50-250 ng/spot for DW spectrophotometric method and HPTLC method, respectively, and 5-50 microg/ml for RIF using DW spectrophotometric method. Both the methods were found to be specific, accurate and reproducible. The proposed methods were successfully applied to determine the rate of degradation of RIF to 3-FRSV in dissolution medium (0.1 N HCl) and also in presence of isoniazid (INH). The rate of degradation of RIF in presence of INH was almost two times more than that of RIF alone. These methods were utilized to study the stability of RIF in market formulations of RIF and RIF with INH in dissolution medium. It has been observed that RIF degrades by 12.4% to form 3-FRSV (RIF formulations) while in presence of INH the degradation is catalyzed to about 21.5% (RIF+INH formulations), in 45 min. Thus, lower concentration of RIF may be available for absorption leading to poor bioavailability of RIF from combination dosage forms (RIF+INH) as compared to formulations containing only RIF. It is proposed that specific analytical method should be used to measure RIF in presence of 3-FRSV in a dissolution study.

Crystal structures of two plasmid copy control related RNA duplexes: An 18 base pair duplex at 1.20 A resolution and a 19 base pair duplex at 1.55 A resolution

The structures of two RNA duplexes, whose sequences correspond to portions of the ColE1 plasmid copy control RNA I and RNA II, have been determined. Crystals containing the 18mers 5'-CA CCGUUGGUAGCGGUGC-3' and 5'-CACCGCUACCAACGGUGC-3' diffract to 1.20 A resolution while those containing the 19mers 5'-GCACCGUUGGUAGCGGUGC-3' and 5'-GCACCGCUACCAACGGUGC-3' diffract to 1.55 A resolution. Both duplexes are standard A form, with Watson-Crick base pairing throughout. Use of anisotropic atomic displacement factors in refinement of the 1.20 A structure dramatically improved refinement statistics, resulting in a final R(free) of 15.0% and a crystallographic R-factor of 11.6%. Perhaps surprisingly, these crystals of the 18 base pair RNA exhibit a 36-fold static disorder, resulting in a structure with a single sugar-phosphate backbone conformation and an averaged base composition at each residue. Since the sugar-phosphate backbone structure is identical in the 36 different nucleotides that are superimposed, there can be no sequence-dependent variation in the structure. The average ribose pucker amplitude is 45.8 degrees for the 18 base pair structure and 46.4 degrees for the 19 base pair structure; these values are respectively 19% and 20% larger than the average pucker amplitude reported from nucleoside crystal structures. A standard RNA water structure, based on analysis of the hydration of these crystal structures and that of the TAR RNA stem [Ippolito, J. A., and Steitz, T. A. (1998) Proc. Natl. Acad. Sci. U.S.A. 95, 9819-9824], has been derived, which has allowed us to predict water positions in lower resolution RNA crystal structures. We report a new RNA packing motif, in which three pro-S(p) phosphate oxygens interact with an ammonium ion.

Seroprevalence of HIV, HBV, and syphilis and associated risk behaviours in male transvestites (Hijras) in Karachi, Pakistan

In Pakistan, male sex workers are predominantly transvestites and transsexuals known as Hijras. In 1998 in Karachi, Pakistan, we studied the seroprevalence of HIV, HBsAg and syphilis and associated risk factors in Hijras. Study subjects were verbally administered a structured questionnaire that determined risk behaviours for sexually transmitted and blood-borne diseases and knowledge of AIDS/STDs. After pre-test counselling, verbal consent was taken for serological testing. The results were provided on a one-on-one post-test counselling session. Three hundred male transvestites were approached; all agreed to answer the questionnaire, 208 consented to blood testing. Of 300, 81% acknowledged commercial sex with men. Of 208, prevalence of syphilis was 37%; HBsAg 3.4%; HIV 0%. The prevalence of HIV and hepatitis B virus (HBV) is low in transvestite sex workers but that of syphilis is high. Intervention programmes implemented at this stage can have an impact on HIV and STD prevention.

Effect of renal transplantation (surgical stress) on serum levels of oxidants and reducing system

BACKGROUND

This study attempts to understand the correlation (if any) between surgical stress of renal transplantation and serum levels of pro-oxidant/antioxidants.

METHODS

Twenty-four ESRD patients having undergone transplant surgery followed from day-1 to day-10 postsurgery were investigated for serum levels of MDA, SOD, Vit. C and E. The drug regimen received was immunosuppressant, H2 blockers and antihypertensives as per the situation.

RESULTS

The typical observations indicated elevated serum levels of MDA from preoperative stage reaching peak value 24 hrs after surgery followed by a steady fall and achieving minima on the 10th day. As regards antioxidants enzyme SOD, Vit. C, Vit. E were low from pretransplant day reaching minima 24 hours postoperatively and returning to normal from 7th day.

CONCLUSIONS

The present investigation has amply shown a typical imbalance between pro-oxidant/antioxidants from pretransplant day up to 24 hrs and there after returning to normal level from 7th day suggestive to desired recovery and surgical stress not a limiting factor in way of health progress renal transplant. Dietary intake of Vit. C and E in mega doses can be a good therapeutic measure.

Complications of blade plate removal

The AO fixed-angle blade plate is commonly used to obtain fixation in proximal femoral osteotomies. This device provides stable fixation and obviates the need for postoperative immobilization. There are no reports in the literature on the rate and types of complications associated with blade-plate removal. We report our rate and type of perioperative and early postoperative complications associated with removal of fixed-angle blade plates in a pediatric population. With an overall complication rate of 5.3% and a major complication rate of 2.0%, our study showed that removal of the blade plate was a relatively safe procedure in those patients troubled by prominent/painful hardware or skin breakdown.

The 1.8 A crystal structure of a statically disordered 17 base-pair RNA duplex: principles of RNA crystal packing and its effect on nucleic acid structure

The crystal structure of a 17 base RNA oligomer, r(CACCGGAUG GUUCGGUG), has been solved to a resolution of 1.8 A through a combination of molecular replacement, multiple isomorphous replacement phasing, and analysis of observed intensity distributions. The oligomer, which forms a stem-loop in solution, crystallized as a pseudo-infinite duplex in spacegroup P321. The asymmetric unit of the crystal contains four superimposed orientations of the duplex that are out of register, such that backbones superimpose, but base identity differs. This static disorder was initially discovered by brominating a single residue per strand in the sequence, and observing four peaks per strand in difference maps phased with a native molecular replacement solution. The presence of four superimposed duplex "motifs" related by non-crystallographic hypersymmetry was detected by computing <I2>/<I>2 and Wilson ratios for the observed intensities. The observed ratios matched those produced from calculated intensities of a 4-fold statically disordered model. Multi-conformer simulated annealing refinement against a maximum-likelihood target incorporating experimental phase information was used to refine the 4-fold disordered model to an Rfree and R of 29.35% and 25.5%, respectively. The resulting structure reveals four distinct conformations of the duplex, with an average pairwise backbone rmsd of 2.35 A. The structural differences between the four conformations, which can be attributed to differences in packing environment, highlight the possible influence of crystal packing forces on nucleic acid X-ray structures. Analysis of inter-helical packing between symmetry-related molecules reveals an RNA "zipper" that mediates direct phosphate oxygen-2' hydroxyl interactions between close-packed phosphate-sugar backbones. This may be a general mode for RNA tertiary interaction that does not depend on metal ions or primary sequence.

Sub-national response in HIV/AIDS: a case study in AIDS prevention and control from Sindh province, Pakistan

HIV/AIDS in Pakistan is slowly gaining recognition as a public health issue of great importance. However, the responses to the disease have been marred by lack of coordination and commitment. We examine, in this paper, the situation in the Sindh province of Pakistan, which is recognized as having the sole fully functioning AIDS prevention and control programme in the country. In discussing the results of the Sindh programme's activities we highlight progress made as well as gaps in data and surveillance. We also recommend strategies for implementation at the provincial and national levels. In addition this example of a sub-national government programme provides a case study for similar programmes in the region.

Both the lymphotoxin and tumor necrosis factor pathways are involved in experimental murine models of colitis

BACKGROUND & AIMS

Membrane lymphotoxin (LT) alpha/beta, a member of the tumor necrosis factor (TNF) family of immune regulatory molecules, is involved both in the development of secondary lymphoid tissues and the maintenance of organized lymphoid tissues in the adult. Defects observed in the mucosal immune system in animals with a genetically disrupted LTalpha/beta pathway coupled with the expression of LTalpha/beta in activated T cells motivated an examination of the importance of this pathway in experimental colitis.

METHODS

Soluble LTbeta receptor (LTbetaR) immunoglobulin fusion protein was used to inhibit the LTalpha/beta/light axis in two independent rodent models of colitis: CD45RBhi CD4(+)-reconstituted SCID mice and bone marrow-transplanted tg26 mice (BM --> tg26).

RESULTS

Treatment with LTbetaR immunoglobulin attenuated the development of both the clinical and histological manifestations of the disease in these two murine models of colitis. Given the success of TNF inhibitors in the treatment of human Crohn's disease, the effects of LTbetaR immunoglobulin have been compared with antibody to TNF in the BM --> tg26 model, and both treatments were equally efficacious.

CONCLUSIONS

The LT pathway plays a role in the development of colitis as important as that of the TNF system and, therefore, represents a potential novel intervention point for the treatment of inflammatory bowel disease.

Consequences of Fas-ligand and perforin expression by colon T cells in a mouse model of inflammatory bowel disease

BACKGROUND & AIMS

We describe a type of colitis that develops after transplantation of nonallogeneic wt bone marrow cells into T cell- and natural killer cell-deficient Tg26 mice (BM-->Tg26). In these animals, severe wasting and inflammation of the colon correlates with the expansion of mucosal T lymphocytes that displays cytotoxic activity. The aims of this study were to determine the relative contribution of perforin and Fas ligand (Fas-L) expression to the cytotoxic action of these T cells and to examine the influence of each pathway in this model of colitis.

METHODS

Colonic T cells were tested for their ability to mediate Fas- and perforin-dependent killing in redirected cytotoxicity assays. Bone marrow cells from donor mice lacking either Fas-L (gld mice) or perforin (PFPnull mice) or both molecules were used to reconstitute Tg26 mice.

RESULTS

Colon cytotoxic T lymphocyte displayed both Fas- and perforin-dependent killing. Deficiency in perforin, but not Fas-L, resulted in reduced incidence of wasting and, to a lesser extent, severe colitis in BM-->Tg26 animals.

CONCLUSIONS

Colon T cells from BM-->Tg26 mice express both perforin and Fas-L. Although neither pathway is critical in the development of colitis, perforin does have a measurable influence on disease in the BM-->Tg26 colitis model.