Cystic fibrosis and related diseases of the pancreas

The discovery of the gene for cystic fibrosis (CF), the cystic fibrosis transmembrane conductance regulator (CFTR), brought about a new era in the study of this disease. Identification of the molecular target has yielded a flood of data that add to our understanding of the pathogenesis, diagnosis and treatment of CF. The CFTR protein is a cAMP-regulated Cl(-) channel with multiple functions in epithelial cells. In the exocrine pancreas the CFTR plays a key role in the apical Cl(-), HCO(3)(-), and water transport in duct cells. The severe loss of functions, caused by mutations of the CFTR gene, leads to pathological lesions of the pancreas. Over 1200 CFTR mutations and polymorphisms have been identified and their diversity may explain the high level of heterogeneity in the CF phenotype. Mutation analyses of the CFTR gene have revealed a spectrum of CFTR-related diseases that do not fit the classical CF picture but are associated with dysfunction of CFTR, such as chronic pancreatitis.     

Small-intestinal mucosa in pseudoobstruction syndromes

The purpose of this investigation was to determine the frequency and severity of small intestinal mucosal damage in pseudoobstruction syndromes. One hundred eighty-nine interpretable biopsies from 12 patients were blindly reviewed by two investigatiors. The underlying disorders were scleroderma in 7 and idiopathic intestinal pseudoobstruction in 5. All 12 had small-intestinal dilatation on small-bowel series. Eight of the 12 patients had biopsies characterized by moderate, to severe mucosal damage; 3 of these had some biopsies which were flat. The damage did not correlate with: (1) types and numbers of organisms recovered from small intestinal aspirates; (2) duration of illness; (3) degree of dilatation of the proximal small bowel; (4) concentrations of deconjugated bile salts in small intestinal fluid; or (5) amount of fat absorbed in fat-balance studies. We conclude that mucosal damage is common in pseudoobstruction syndromes. The pathogenesis of the damage and its relationship to intraluminal bacteria remain undefined.     

A potential peptide vaccine against two different strains of influenza virus isolated at intervals of about 10 years.

We have developed a strategy for making synthetic peptide vaccines, in which a peptide, HA127-133, derived from the hemagglutinin (HA) of A/Aichi/2/68(H3N2) influenza virus (Aichi/68) is introduced into the Ab binding component consisting of 43-46 and 54-58 residues of a pigeon cytochrome c analogue peptide, 46F50V54A. Indeed, this hybrid peptide, 46F/HA127-133/54A, induced impressive T-cell responses and antibody production neutralizing infectivity of Aichi/68 in vitro. In a subsequent study we found that 46F/HA127-133/54A(18mer) peptide antigen, which had been prepared by substitution at the central five residues of 46F50V54A with HA127-133, generated T-cell responses and neutralizing antibody responses as well. On the basis of these prior findings, in the present study we analyzed immunopotency of 46F/HA127-133/54A(18mer) in vivo administered in several ways to I-Ab mice. We show herein that this peptide vaccine loaded in multilamellar liposomes without adjuvant protects the mice against infection with Aichi/68 within 2 weeks after final immunization. Further, this peptide vaccine was shown to be effective in preventing infection with a naturally occurring antigenic variant, A/Texas/1/77(H3N2), carrying the same sequence at 127-133 of the HA as Aichi/68 virus. Since this part of the HA is relatively conserved among H3 subtype influenza viruses, our peptide vaccine may become the basis for a new strategy to prepare effective vaccines that will overcome the ineffectiveness of classical vaccines attributable to antigenic drift of influenza viruses.     

Effect of 2'-deoxycoformycin on erythroid, granulocytic, and T- lymphocyte colony growth

The finding of elevated intracellular levels of adenosine deaminase (ADA) in some patients with acute lymphoblastic leukemia has led to attempts to control this disease with the adenosine deaminase inhibitor 2'-deoxycoformycin (dCF). Because of clinical reports indicating its relative freedom from myelotoxicity, we have tested the effects of this drug on erythroid, granulocytic, and T-lymphocyte colony formation by normal marrow and peripheral blood cells. While clinically the drug has been found to be active at serum concentrations of approximately 10 microM, we have tested it at concentrations up to and including 1 mM. It was found that both erythroid and granulocytic colony growth was completely unaffected by 1 mM dCF, a concentration at least 2 magnitudes higher than that necessary to totally ablate intracellular ADA levels. T-lymphocyte colony growth was unaffected by 100 microM dCF, but at 1 mM some inhibition was observed. These findings therefore indicate that dCF, while able to cause leukemic cell lysis in vivo, has no inhibitory effect on the proliferative capacity of normal hematopoietic cells.     

Status of TIM-1 exon 4 haplotypes and CD4+T cell counts in HIV-1 seroprevalent North Indians

The TIM (T cell/transmembrane, immunoglobulin and mucin) proteins are crucial regulators of Th1/Th2 immune responses and have been implicated in several diseases including HIV-1/AIDS. The TIM1 exon 4 that codes for mucin domain is highly diverse, with sequence variants associated with varying phenotypes. In this study, TIM1 exon 4 was sequenced among 227 HIV-1 seroprevalent and 288 healthy non infected individuals from North Indian population and haplotypes established. A novel but rare haplotype D1^∗ was identified among the healthy and differed from D1 by a synonymous substitution G>T at Thr208Thr. The TIM1 haplotype diversity showed no association with susceptibility to HIV-1 infection. The seroprevalent individuals carrying D3A had relatively higher median CD4+T cell counts (368/μl) than those without (313/μl; p = 0.02). A comparison of CD4+T counts between D3-A individuals on ART or ART naïve did not show any significant difference plausibly due to confounding nature of ART and other factors.     

Bradykinin and angiotensin-converting enzyme inhibition in cardioprotection

OBJECTIVES:

To show that angiotensin-converting enzyme (ACE) inhibition potentiates subthreshold ischemic preconditioning (IPC) via the elevation of bradykinin activity, leading to a fully delayed cardioprotective response.

METHODS:

On day 1 of the experiment, pigs were subjected to sham (group 1, controls) or IPC protocols. In groups 2 and 3, 4×5 min and 2×2 min of IPC, respectively, were elicited by occluding the left anterior descending coronary artery with percutaneous transluminal coronary angioplasty inflatable balloon catheter. Group 4 was subjected to the ACE inhibitor perindoprilate only. In group 5, the pigs were pretreated with perindoprilate (0.06 mg/kg) and then subjected to 2×2 min IPC. In group 6, intracoronary HOE 140 (a selective bradykinin B₂ receptor antagonist) was added before the perindoprilateaugmented subthreshold (2×2 min) PC stimulus. On the second day, all animals underwent 40 min left anterior descending coronary artery ligation and 3 h reperfusion, followed by infarct size analysis using triphenyl tetrazolium chloride staining.

RESULTS:

The rates of infarct size and risk zone were the following in the experimental groups: group 1, 42.8%; group 2,19.5% (P<0.05); group 3, ischemia/reperfusion (I/R) 33.4%; group 4, I/R 18.4% (P<0.05); group 5, I/R 31.2%; and group 6, I/R 36.3%. A significant increase of nuclear factor kappa B activation in groups 2 and 4 was seen.

CONCLUSIONS:

Results confirm that ACE inhibitors do not give total pharmacological IPC, but they enhance the induction effect of small ischemic insults, which raises the ischemic tolerance of myocardium. It was determined that enhanced bradykinin activity leads to downstream nuclear factor kappa B activation in this model.