The discovery and structure-activity relationships of nonpeptide, low molecular weight antagonists selective for the endothelin ET(B) receptor

The systematic modification of the ETA selective N-(5-isoxazolyl)benzene-sulfonamide endothelin antagonists to give ETB selective antagonists is reported. The reversal in selectivity was brought about by substitution of the 4-position with aryl and substituted aryl groups. Of all the aromatic substituents studied, the para-tolyl group gave rise to the most active and selective ETB antagonist. Larger substituents caused a decrease in both ETB activity and selectivity. A similar trend was observed by substitution at the 5-position of the N-(5-isoxazolyl)-2-thiophenesulfonamide ETA receptor antagonists. The para-tolyl group was again found to be optimal for the ETB activity and selectivity. The structural features that were found to be favorable for binding to the ETB receptor, that is, the presence of a linear, conjugated pi-system of definite shape and size, have been successfully incorporated into the design of ETB selective polycyclic aromatic sulfonamides antagonists.     

ICAM-1 upregulation in distant tissues after hepatic ischemia/reperfusion: a clue to the mechanism of multiple organ failure

BACKGROUND/PURPOSE: Endothelial cell adhesion molecules (ECAMs) are felt to play an important role in ischemia/reperfusion (I/R) injury by causing adhesion of leukocytes to endothelial cells. It is possible that ECAMs play a role in multiple organ system failure. ICAM-1 is one of the adhesion molecules that has been shown to be upregulated in response to cytokines. This upregulation leads to leukocyte endothelial cell interaction (adhesion) and to neutrophil infiltration of the affected tissue. The purpose of our study was to measure ICAM-1 expression in the liver and other organs after hepatic ischemia/reperfusion (I/R). METHODS: A laparotomy was performed on 14 Sprague-Dawley rats; 45 minutes of occlusive ischemia to the left lateral lobe was followed by 5 hours of reperfusion. The rat was injected with I125-labeled ICAM-1 MAb and I131-labeled nonbinding MAb (to control for nonspecific accumulation of ICAM-1 MAb). Entire organs were harvested and accumulated activity was measured in each organ. ICAM-1 levels were expressed as percent injected dose per gram of tissue. Control animals underwent sham laparotomy. RESULTS: ICAM-1 was upregulated in the ischemic lobe of the liver, nonischemic lobe of the liver, heart, kidney, intestine, and pancreas. Up-regulation in the lung was not significant. Both the lung and liver had high constitutive levels of ICAM-1. CONCLUSIONS: These data show that (1) significant hepatic upregulation of ICAM-1 after hepatic ischemia/reperfusion and (2) significant ICAM-1 upregulation in other tissues (heart, kidney, and intestine) after hepatic ischemia/reperfusion. The ICAM-1 upregulation in distant organs is likely mediated by cytokines such as tumor necrosis factor (TNF). These data show that leukocyte endothelial cell interactions in distant organs may be mediated by hepatic ischemia/reperfusion. This is a possible explanation for how failure of one organ can lead to failure of others in multiple organ system failure.     

Role of NF-kappaB in immune and inflammatory responses in the gut

BACKGROUND: Liver disease in chronic hepatitis C virus (HCV) infection ranges from minimal lesions to liver cirrhosis, eventually evolving to hepatocellular carcinoma. Whether and how HCV determines the different clinical and histological manifestations of the disease is not fully understood. AIMS: To verify whether the amount of virus in individual patients could be related to the severity of liver injury. PATIENTS AND METHODS: Levels of HCV RNA were measured in serum in 96 consecutive patients with chronic hepatitis type C using a signal amplification assay. The relation between viraemic values and the corresponding viral load in the liver was assessed in a subgroup of 21 patients in whom HCV RNA was measured in serum samples and liver specimens obtained at the same time. RESULTS: A positive correlation was observed between the amount of viral nucleic acid in the two compartments, indicating that levels of viraemia reflect the amount of virus present in the liver. Viral load did not correlate with aminotransferase activities nor with histological diagnosis, and serum and liver levels of HCV RNA were not significantly different in patients infected by the various HCV genotypes. CONCLUSIONS: Measurement of HCV replication in serum is a mirror of viral replication in the liver. The extent of replicative activity of HCV does not seem to play a role in the modulation of the associated hepatic disease.     

Induction of mosaic sex-linked recessive lethals in the different germ cell stages of Drosophila melanogaster by bleomycin

The dead-end filtration characteristics of the dimorphic yeast Kluyveromyces marxianus var. marxianus (formerly fragilis) NRRLy2415 were investigated for a range of mean cell morphologies, ranging from predominantly yeast-like to predominantly filamentous. Semiautomated image analysis was used to measure the mean cell specific surface area, Sv, and the mean ratio of cell length to equivalent cylindrical diameter, Ldm, in each broth. The method of Ju and Ho (Biotechnol. Bioeng. 1988, 32, 95-99) was used to show that for broths with Ldm values between 1.72 and 10.03, the voidage of cell pellets formed by centrifugation increased with increasing Ldm. In the pressure range 30-180 kPa, the specific filter cake resistance, alpha, was found to be related to pressure, DeltaP, through the equation alpha = alpha0(1 + kcDeltaP). The dependence of alpha0/Sv2 on Ldm was found to be qualitatively consistent with the pellet voidage data and the Carman-Kozeny equation. Considerably better agreement with the experimental data was obtained when the Kozeny constant, K, was treated as variable and related to Ldm through the equation K = 4.83 + 7.08 log10 Ldm. The cake compressibility constant, kc, was found to increase with increasing Ldm, a phenomenon consistent with the wide range of voidages that can be displayed by beds of long cylinders.     

IL-5 is required for eosinophil recruitment, crystal deposition, and mononuclear cell recruitment during a pulmonary Cryptococcus neoformans infection in genetically susceptible mice (C57BL/6)

CBA/J (highly resistant), BALB/c (moderately resistant), and C57BL/6 (susceptible) mice displayed three resistance patterns following intratracheal inoculation of Cryptococcus neoformans 52. The inability to clear the infection correlated with the duration of the eosinophil infiltrate in the lungs. The role of IL-5 in promoting the pulmonary eosinophilia and subsequent inflammatory damage in susceptible C57BL/6 mice was investigated. C57BL/6 mice developed a chronic alveolar, peribronchiolar, and perivascular eosinophilia following C. neoformans infection. This resulted in the accumulation of intracellular Charcot-Leyden-like crystals in alveolar macrophages by wk 4 and the extracellular deposition of these crystals in the bronchioles with associated destruction of airway epithelium by wk 6. IL-5 mRNA was expressed in the lungs, and injections of anti-IL-5 mAb prevented eosinophil recruitment and crystal deposition but did not alter cryptococcal clearance. Depletion of CD4+ T cells (but not CD8+) ablated IL-5 production by lung leukocytes in vitro and eosinophil recruitment in vivo. Neutralization of IL-5 also inhibited the recruitment of macrophages, CD8+ T lymphocytes, and B lymphocytes by 47 to 57%. Anti-IL-5 mAb inhibited CD4+ T lymphocyte recruitment by 30% but did not affect neutrophil recruitment. Thus, the development of a chronic eosinophil infiltrate in the lungs of C. neoformans-infected C57BL/6 mice is a nonprotective immune response that causes significant lung pathology. Furthermore, IL-5 promotes the recruitment and activation of eosinophils, resulting in the recruitment of additional macrophages and lymphocytes into the lungs.     

Comparative study between corpus cavernosum-electromyography findings and electron microscopy of cavernosal muscle biopsies in erectile dysfunction patients

BACKGROUND/AIMS: The colonic response to obstruction is poorly understood. Thickening of the proximal bowel following colonic stricture may be due to increased protein synthesis. We have investigated the colonic morphology and collagen concentration during the development of left-sided colonic obstruction in an animal model. METHODS: Twelve male Wistar rats received either a silk ligature obstruction of the colon 2.5 cm above the peritoneal reflection (n = 6) or manipulation of the left colon (controls, n = 6). Twenty-four hours later, three colonic specimens from the ligature zone and from 1 cm proximal and distal to this site, or from equivalent regions in controls, were assayed for hydroxyproline concentration. RESULTS: In controls there was no difference in hydroxyproline concentration between colonic sites. In obstructed rats, the hydroxyproline concentration was greater both at the ligature and distally, when compared with the proximal region. The hydroxyproline concentration was higher (p < 0.05) than corresponding control values at the ligature site (14.95 +/- 2.76 vs. 10.97 +/- 1.95 microgram/mg of dry tissue mean +/- s.d.) but not on either side. CONCLUSION: The colonic collagen concentration is equivalent or raised near an obstruction, demonstrating that obstructed colon may possess an enhanced capacity to hold sutures.     

Regression of childhood Barrett's esophageal mucosa by antireflux surgery and bipolar electrocoagulation

The authors report a case of a 13-year-old girl with Barrett's esophagus who underwent antireflux surgery and was subsequently treated with endoscopic thermal coagulation using bipolar electrocoagulation. Follow-up endoscopy 15 months after completion of the endoscopic therapy showed normal esophageal mucosa without intestinal metaplasia. Longer follow-up is needed to assess the long-term effects of endoscopic treatment of the Barrett's mucosa with thermal coagulation, and this procedure should still be considered under investigation.     

Modulation of RecA nucleoprotein function by the mutagenic UmuD'C protein complex

The RecA, UmuC, and UmuD' proteins are essential for error-prone, replicative bypass of DNA lesions. Normally, RecA protein mediates homologous pairing of DNA. We show that purified Umu(D')2C blocks this recombination function. Biosensor measurements establish that the mutagenic complex binds to the RecA nucleoprotein filament with a stoichiometry of one Umu(D')2C complex for every two RecA monomers. Furthermore, Umu(D')2C competitively inhibits LexA repressor cleavage but not ATPase activity, implying that Umu(D')2C binds in or proximal to the helical groove of the RecA nucleoprotein filament. This binding reduces joint molecule formation and even more severely impedes DNA heteroduplex formation by RecA protein, ultimately blocking all DNA pairing activity and thereby abridging participation in recombination function. Thus, Umu(D')2C restricts the activities of the RecA nucleoprotein filament and presumably, in this manner, recruits it for mutagenic repair function. This modulation by Umu(D')2C is envisioned as a key event in the transition from a normal mode of genomic maintenance by "error-free" recombinational repair, to one of "error-prone" DNA replication.     

Culture-positive tuberculosis in human immunodeficiency virus type 1-infected children

BACKGROUND: Adults infected by HIV have increased susceptibility to Mycobacterium tuberculosis and progress more rapidly to disease. HIV and tuberculosis (TB) coinfection in children has been reported but often lacks bacterial confirmation. We report on the clinical picture, special investigations, clinical course and outcome of 14 children with HIV infection and culture-confirmed TB from a developing country. METHODS: The clinical records of all children, from 1992 to 1997, with HIV infection and culture-proved TB were reviewed. RESULTS: Fourteen (10.4%) of 135 children with vertically transmitted HIV infection, 93% <2 years of age, fit the criteria. Nonresolving pneumonia (4) and otorrhoea (6) were common complaints. A Mantoux test was positive (> or =15 mm) in 6 of 11 children. Extrapulmonary TB was present in 5 cases. Ear swabs were the source of M. tuberculosis culture in 3. Chest radiographs were abnormal in all with hilar and paratracheal lymphadenopathy present in 7. A source case with pulmonary TB was identified for 10. Susceptibility tests were done on 9 strains of which 1 was drug-resistant. Four children were culture-positive 4 to 10 months after initiation of TB treatment. Mortality was 21% and 3 were lost to follow-up. CONCLUSIONS: In HIV-infected children the Mantoux skin test remains useful and culture specimens should be obtained from all sources. Response to treatment is unpredictable, and for this reason repeated cultures should be taken during treatment and a 9-month course of treatment considered.