A neosynthesis of sodium channels is involved in the evolution of the sodium current in isolated adult DUM neurons

Short-term culture of isolated adult dorsal unpaired median (DUM) neurons of the cockroach Periplaneta americana has been used to study the evolution of the sodium current during the time in culture after axotomy and deafferentation treatment. An increase in the maximum peak amplitude of the sodium current recorded under voltage-clamp conditions with the patch-clamp technique in the whole-cell recording configuration, was only observed between 24h and 72h (75%) without any modification of the kinetics and the voltage-dependence of the current. A decrease in the level of foetal calf serum in the culture medium reduces the amplitude of the sodium current on all days but does not affect its time-course of development which was on the contrary completely abolished by both protein synthesis inhibitors, actinomycin D and cycloheximide. The results obtained in these neurons strongly suggest that a neosynthesis of sodium channel proteins is involved in the evolution of the sodium current induced by axotomy and deafferentation.     

Infection of ascitic fluid by perforation of a sclerodermic colon]

In progressive systemic scleroderma, a disease of protean manifestations, involvement of the gastrointestinal tract is noted infrequently in patients who are asymptomatic, and is rarely fatal. We report the case of a 65-year-old woman who was admitted for ascitis related to a non A, non B cirrhosis. The patient presented with bacterial peritonitis due to colonic perforation by fecal impaction associated with sclerodermic involvement. Pathologic study of the resected colon showed that the true muscularis was very atrophic and fibrotic, characteristic of scleroderma. To our knowledge, this cause of ascitic fluid infection has not been previously reported.     

Expression of cytokeratins 7 and 20 in carcinomas of the extrahepatic biliary tract, pancreas, and gallbladder

BACKGROUND: Expression of cytokeratins 7 (CK7) and 20 (CK20) may help distinguish the site of origin for metastatic carcinomas. Little is known regarding their expression in biliary tract and pancreatic carcinomas. Our aim was to study the expression of CK7 and CK20 in these tumors. DESIGN: Fifty-three carcinomas of the extrahepatic bile ducts (n = 8), ampulla of Vater (n = 7), gallbladder (n = 11), and pancreas (n = 27), were retrieved from the surgical pathology files of the University of Massachusetts Medical Center. Formalin-fixed, paraffin-embedded sections were immunostained with mouse monoclonal antibodies to CK7 and CK20 using an avidin-biotin immunoperoxidase technique with microwave antigen retrieval. The percentage of cells positive for each antibody was assessed on a scale of 0 to 3 (0, <10%; 1+, 10% to 50%; 2+, 51% to 90%; 3+, >90%). RESULTS: The majority of carcinomas in all groups were positive for CK7 (CK7+) and negative for CK20 (CK20-). Of the CK7+ tumors, the majority of tumors in each group were 3+ positive. CONCLUSIONS: (1) Carcinomas of the extrahepatic biliary tract and pancreas are strongly positive for CK7 and negative for CK20 and can be included in the differential diagnosis of other carcinomas with this profile in metastatic sites. (2) The CK7/CK20 immunostaining profile will not identify the site of origin for tumors with extensive growth in the porta hepatis region.     

CD4+/CD8+ ratio of liver-derived lymphocytes is related to viraemia and not to hepatitis C virus genotypes in chronic hepatitis C.

The pathogenic mechanisms that lead to chronic hepatitis C are unknown. As hepatitis C virus (HCV) has been shown to induce T cell response, we assessed whether a particular T lymphocyte subset could be preferentially detected in the liver of patients with chronic hepatitis C in relation to viraemia or HCV genotypes. The immunophenotypes of liver-derived lymphocytes were analysed in 26 patients by flow cytometry and immunohistochemistry. Viraemia was quantified by branched DNA assay. Using this assay, HCV RNA was not detectable in six patients. HCV RNA was detected in 20 patients, and titres ranged from 8 to 137 x 10(6) Eq/ml. Genotyping was performed using a line probe assay. Type 1a, 1b, 2a, 3a and 4a were found to infect 2, 10, 2, 7 and 3 patients, respectively. The CD4+/CD8+ ratio of liver-derived lymphocytes was significantly higher (P < 0.01) in patients with detectable viraemia than in patients without detectable viraemia. In contrast, neither the percentage of gamma/delta T lymphocytes nor that of CD2+CD57+ cells was different in the groups. When comparing the CD4+/CD8+ ratio, the percentage of gamma/delta T lymphocytes or CD2+CD57+ cells according to genotype, the differences were not significant. These results suggest that the CD4+/CD8+ ratio of liver-derived lymphocytes is related to viraemia but not to HCV genotypes in patients with chronic hepatitis C, and that T lymphocytes may be involved in the pathogenesis of liver lesions in chronic hepatitis C.     

Occurrence of secretogranin II in the prolactin-immunoreactive neurons of the rat lateral hypothalamus: an in situ hybridization and immunocytochemical study

The occurrence of secretogranin II in a neuron population of the rat lateral hypothalamus specifically detected by an anti-serum to ovine prolactin was examined. As this population was previously reported to synthesize dynorphin, the distribution of neurons recognized by ovine prolactin-, dynorphin B- and secretogranin II anti-sera was investigated on adjacent sections of hypothalami. The prolactin immunoreactive neurons were the only cells in the lateral hypothalamus to be stained by secretogranin II anti-serum. Moreover, coupling immunocytochemical detection and in situ hybridization with an oligonucleotide probe complementary to secretogranin II mRNA showed that these neurons expressed the secretogranin II gene. These new findings should help to study the physiological role of the prolactin immunoreactive neurons of the lateral hypothalamus.     

Detection of extended broad-spectrum beta-lactamases inEnterobacteriaceae in four French hospitals

In 210 strains ofEnterobacteriaceae which were isolated in four hospitals and which showed reduced susceptibility to cefotaxime, high synergy was demonstrated between amoxicillin (20µg) + clavulanate (10µg) and cefotaxime (30µg) using a simple double-disk test. Isoelectric focusing on gel and specific iodometric detection using ceftriaxone identified four extended broad-spectrum-lactamases (isoelectric points 7.6, 6.3, 7.0 and 5.9) produced by the strains.     

Quantification of plasma and intracellular levels of the HIV protease inhibitor ritonavir by competitive ELISA

The HIV protease inhibitor ritonavir (Norvir; ABT-578), currently used in combination with nucleoside analogs and other protease inhibitors in anti-HIV therapy, has previously been quantified by an HPLC procedure. Here, we report the first convenient one-step competitive ELISA for measuring plasma and intracellular ritonavir in HIV patients. Anti-ritonavir antibody was raised in rabbits using ritonavir-KLH conjugate as immunogen, and the enzymatic tracer was prepared by coupling the drug to acetylcholine esterase. Samples for analysis were first extracted with methanol. Bound/free separation was achieved in a microtiter plate previously coated with anti rabbit IgG monoclonal antibody. Fifty percent inhibition was observed at 1 ng/ml ritonavir and the method accurately and specifically detected as little as 3-4 ng/ml of plasma ritonavir as well as intracellular drug in the peripheral blood mononuclear cells of patients undergoing ritonavir therapy. Within-run and day to day coefficients of variation were below 10% and the drugs currently used in HIV therapy did not interfere with the test. The ELISA was applied to the measurement of plasma ritonavir and to the determination of the extracellular/intracellular drug level ratios in HIV patients receiving long-term multidrug therapy.