Hemocompatibility in hemodialysis and erythropoietin therapy

Two studies designed to investigate the effect of recombinant human erythropoietin (rHuEPO) treatment of anemia in chronic dialysis patients on hemocompatibility were conducted. Study 1, whose main aim was to establish whether treatment with rHuEPO enhances coagulation activation during dialysis, included 15 patients before rHuEPO therapy at a mean hematocrit (HCT) of 22.3% and then during therapy at a HCT of 29.3%. The plasma concentrations of the thrombin-antithrombin III complex were not higher during rHuEPO therapy than before it when performing hemodialysis with a Cuprophan membrane. No significant difference was demonstrated either in the values of activated clotting times (Hemochron), thrombocyte or white blood cell counts (Coulter S+II), or in plasma C5a concentrations (ELISA) established during dialysis sessions before and during rHuEPO therapy. In Study 2, which focused primarily on the question of whether or not rHuEPO therapy increases thrombocyte activation during hemodialysis, 8 patients on chronic dialysis were examined both before therapy at a mean HCT value of 22.1% and during rHuEPO therapy at a HCT of 31.5%, invariably during dialysis with either a Cuprophan or polyacrylonitrile (AN69HF) membrane. The plasma concentrations of beta-thromboglobulin (ELISA) did not differ between the examinations made during rHuEPO and before rHuEPO therapy; however, statistically significant differences were found between dialysis sessions involving Cuprophan and AN69HF membranes. No significant difference between examination before and during rHuEPO was demonstrated in activated clotting time nor thrombocyte and white blood cell counts in this study either. The authors conclude that rHuEPO therapy does not enhance coagulation activation during hemodialysis, does not have an effect on thrombocyte activation, and does not influence complement activation and changes in white blood cell counts.     

A genetic model for undifferentiated cell tumor formation: similar tumors formed by different cell lines transformed by the E1A oncogene

The activation of oncogenes and the mutation/deletion of suppressor genes may be involved in tumor heterogeneity. In an attempt to study tumor heterogeneity, we transformed cell lines from epithelial (PAM 212), mesenchymal (NIH-3T3), or melanocytic origin (L-BIOBR) with the wild type E1a oncogene. To make the cell lines tumorigenic, cells were infected with Harvey sarcoma virus carrying the v-H-ras oncogene. The transformed cells were injected into nude mice and the tumors studied by optical and electron microscopy. The tumors formed by v-H-ras-transformed cells consisted of epitheliod melanomas, spindle cells sarcomas and poorly-differentiated carcinomas, depending on the cell of origin. In contrast, the tumors obtained from cells also carrying the E1a oncogene showed a predominant small and undifferentiated cell pattern regardless of the cell of origin. We conclude that the E1a oncogene products induce a negative control of differentiation, independent of the cell type, and that tumors formed by cells carrying the E1a oncogene display an undifferentiated cell pattern.     

Helicobacter pylori at Hospital Santo Tomás

We studied the incidence of infection with Helicobacter pylori in Panamanians with chronic dyspepsia, gastric or duodenal ulcer, gastritis or gastric cancer. The histopathology was positive in 54 (81%) of 66 patients; the urea test was positive in 52 (82.5%) of 63 cases; the impromptu was positive in 51 (79.6) of 64 patients; the endoscopic examination was positive in 64 (82.9%) of 77 examinations.     

Cisapride reduces neonatal postoperative ileus: randomised placebo controlled trial

AIM: To assess the efficacy of cisapride in reducing ileus persisting to the tenth postoperative day after neonatal abdominal surgery. METHODS: A prospective, randomised, double blind trial comparing rectal cisapride (1.4-2.3 mg/kg/day) with placebo over seven days was undertaken in 33 neonates. RESULTS: Seven of 12 (58%) patients receiving placebo and eight of 11 (73%) receiving cisapride achieved a first sustained feed during treatment. Of those receiving cisapride, the first sustained feed occurred at 2.3 days (SEM 0.6) compared with 4.7 days (SEM 0.8) with placebo. By the seventh day the mean daily net enteral balance was 69 (SEM 18) ml/kg in the cisapride subgroup and 17 (SEM 8) ml/kg for those receiving placebo. Stool was passed on 6.3 (SEM 0.4) treatment days in the cisapride subgroup compared with 4.1 (SEM 1.0) treatment days in the placebo subgroup. CONCLUSION: Cisapride is effective in neonates with a prolonged ileus after abdominal surgery.     

NADPH-diaphorase-stained neurons after experimental epilepsy in rats

The aim of this study was to determine the neuronal participation of nitric oxide (NO) in experimental epilepsy. To reach this objective, we established the amount of cells presenting nitric oxide synthase (NOS) and the amygdaline concentrations in the L-arginine-nitric oxide synthesis pathway. A group of fully epileptic rats, induced by the kindling procedure and that had reached at least 10 generalized seizures, was studied. We evaluated behavioral stages, electroencephalographic activities, and histochemical NOS-positive cells and carried out high-pressure liquid chromatography (HPLC) determinations of arginine, citrulline, and glutamic acid. Our results showed that behavioral and electrographic frequency, and duration of epileptic activities, were increased during the kindling process. Image processing system of NOS cells showed two types of intensities in cell stains in hippocampus, caudate-putamen, and amygdala. When we independently counted the two types of NOS stain cells, a selective increase in the number and density of weak-stained cells was observed, while dark-stained cells did not change in the studied structures. Additionally, arginine, citrulline, and glutamic acid concentrations in amygdala increased in kindled animals. The differential and specific increase in the stained cells expressing the nitric oxide synthase, as well as the increase in concentrations of the L-arginine-nitric oxide pathway in amygdala, suggested a relationship with the progressive augmentation in the electrophysiological hyperactivity characteristic of generalized epilepsy.