[Efficacy of a new microencapsulated pancreatin versus a conventional preparation, in the treatment of steatorrhea of pancreatic origin]

Malabsorption of pancreatic origin has been traditionally treated with pancreatic enzymes, but the effectiveness of treatment has been limited, related to the scant enzymatic activity of preparations, enzyme lability to acid attack and deficient mixing with the intestinal bolus, among other factors. We studied the efficacy of a new pancreatic enzyme preparation in the form of pellets, which mix easily with the intestinal bolus, are protected against gastric acid attack and have a high lipase concentration (Creon, Kalichemie-Pharma), as compared to traditional unprotected pancreatin in the form of tablets (Pankreon 700). The study was open, comparative and crossover, and included 12 patients. The diagnosis was chronic alcoholic pancreatitis in 10 cases and idiopathic pancreatitis in 2, with a steatorrhea of more than 10 g/24 h and a basal gastric pH less than 2.5. The duration of treatment was 3 weeks, using a diet containing 100 g of fat. The first week served as a control, and in the 2nd and 3rd treatment was given in the form of 7 capsules of Creon (2.1 g pancreatin and 70,000 UFIP lipase) or 17 tablets of Pankreon 700 (11.9 g pancreatin and 476,000 UFIP lipase) by randomized assignment. Our results confirm the beneficial effects observed by others. Steatorrhea was significantly reduced, up to 45.6% with Pankreon 700 and 57% with Creon, in spite of a dose that had 6.8 times less lipase activity, 5.6 times less pancreatin weight and 2.4 times fewer units ingested (capsules/tablets). Patients showed significant weight gain. At 30 days of treatment with Creon, steatorrhea had declined 70% and the weight gain was significant.(ABSTRACT TRUNCATED AT 250 WORDS)

[Acute hepatitis in heroin addicts: etiologic and follow-up study of 110 cases]

In order to know the etiology and natural history of acute viral hepatitis in intravenous drugs abusers, a panel of 110 heroin addicts, suffering acute hepatitis, is studied. The B virus, by itself or in conjunction with the delta virus was responsible for 63 cases. 35 patients suffered of NANB hepatitis and only two patients were diagnosed of hepatitis A. Delta infection was detected in 38 of the 77 cases of HBsAg-positive acute hepatitis. All the hepatitis B patients had serum conversion within the first 6 months of the acute episode. All the patients suffering acute delta hepatitis and 75% of those suffering non-A, non-B hepatitis, developed chronic hepatic disease. We conclude that in our environment, the B virus is the main responsible for acute hepatitis in heroin addicts. Delta infection is detected in almost half of the heroin addicts with HBsAg-positive acute hepatitis. The acute hepatitis caused by B virus, or by B and delta viruses simultaneously, have a satisfactory evolution, thus, almost all the cases are cured within 6 months. On the contrary, hepatitis caused by NANB or delta viruses usually progresses to chronic hepatic disease.

Vanadate as an inhibitor of plant and mammalian peroxidases

Vanadate ions are shown to inhibit horseradish, squash, and rat intestinal peroxidases by following the reaction spectrophotometrically in a wide range of vanadate concentrations. I50 in phosphate buffer were 43, 9.4, and 535 microM, respectively. No inhibitory effect was found on cow milk lactoperoxidase and beef liver catalase. Gel filtration of peroxidases in the presence of vanadate, as carried out by radioactive 48V for horseradish peroxidases (either in aerobic or anoxic conditions) and neutron activation analysis (NAA) for squash peroxidase, demonstrated a binding of vanadium to these enzymes in stoichiometric amounts. Electron paramagnetic resonance spectra of the eluted peaks for the former peroxidase indicated that vanadium is in the +5 oxidation state, but an equilibrium between V (V) and V (IV) in the assay conditions cannot be discarded. Although the inhibitory mechanism remains obscure, some hypotheses are considered. The potential implications that the inhibitory effect of vanadium might have on plant and animal metabolism are also discussed.

Analysis of the thermal unfolding of porcine procarboxypeptidase A and its functional pieces by differential scanning calorimetry

Porcine pancreatic procarboxypeptidase A and its tryptic peptides, carboxypeptidase A and the activation segment, have been studied by high-sensitivity differential scanning calorimetry (DSC). The thermal denaturation of the zymogen and the active enzyme has been carried out at two pH values, 7.5 and 9.0, at different ionic strengths and at different scan rates. The endothermic transitions for these two proteins were always irreversible under all conditions investigated. The denaturation behaviour of both proteins seems to fit very well with the kinetic model for the DSC study of irreversible unfolding of proteins recently proposed by one of our groups. From this model, the activation energies obtained for the denaturation of the pro- and carboxypeptidase were 300 +/- 20 kJ mol-1 and 250 +/- 14 kJ mol-1 respectively. On the other hand, the isolated activation segment appears as a thermostable piece with a highly reversible thermal unfolding which follows a two-state process. The denaturation temperature observed for the isolated segment was always at least 15 K higher than those of the zymogen and the active enzyme.

Preliminary X-ray crystallographic study of adenylosuccinate synthetase from Escherichia coli

Adenylosuccinate synthetase, a dimeric enzyme of 96,000 Mr, catalyzes the first committed step toward the de novo biosynthesis of AMP. Large, single crystals of adenylosuccinate synthetase from Escherichia coli grow from solutions of polyethylene glycol and ammonium sulfate. Crystals from ammonium sulfate belong to the orthorhombic space group P212121 with unit cell parameters a = 79.0 A, b = 70.2 A and c = 152.6 A. Crystals from polyethylene glycol belong to the space group P21, having unit cell parameters of a = 71.16 A, b = 71.99 A, c = 82.95 A, and beta = 71.52 degrees. The asymmetric units of both crystal forms probably contain the entire dimeric enzyme.

Isolation and characterization of a NADH-dehydrogenase from rat liver mitochondria

Mitochondrial NADH dehydrogenase has been purified from rat liver mitochondria by protamine sulfate fractionation and DEAE-Sephadex chromatography. The enzyme is water-soluble and its molecular weight has been estimated at 400 +/- 50 kilodaltons. NADH-ferricyanide reductase and NADH cytochrome c reductase activities have been studied and the kinetic parameters have been determined. Both substrates, NADH and the electron acceptor (ferricyanide or cytochrome c) have an inhibitor effect on the reductase activities and the kinetic mechanism of the enzyme is ping-pong bi-bi.

Characterization of a light-dependent glutamate synthase activity in Chlamydomonas reinhardtii

Photosynthetically active vesicles prepared from Chlamydomonas reinhardtii retained a light-dependent glutamate synthase activity which was highly specific for 2-oxoglutarate (Km=2.1 mM) and L-glutamine (Km=0.9 mM) as amido group acceptor and donor respectively. This activity was inhibited by azaserine, p-hydroxymercuribenzoate and 3-(p-chlorophenyl)-1,1-dimethyl urea.Light-dependent synthesis of glutamate was also obtained by coupling Chlamydomonas photosynthetic particles to purified ferredoxin-glutamate synthase, using ascorbate and 2,6-dichlorophenol-indophenol as electron donor. This system was also specific for 2-oxoglutarate (Km=1 mM) and L-glutamine (Km=0.8 mM) as substrates, and was stimulated by dithioerythritol. Azaserine and p-hydroxymercuribenzoate, but not 3-(p-chlorophenyl)-1,1-dimethyl urea, inhibited the reconstituted activity; high concentrations of 2-oxoglutarate were inhibitory.

[Action of domperidone on dopamine-induced inhibition of gastric secretion]

The inhibitory action of dopamine on basal gastric secretion and that stimulated by pentagastrin with previous administration of domperidone in 26 male patients, between 18 and 48 years of age, suffering duodenal ulcer has been studied. The administration of domperidone (0.25 mg/kg) produces a significant reduction of the inhibitory action of dopamine on basal gastric secretion and that stimulated by pentagastrin at dose 0.15 microgram/kg/h. Besides dopamine shows a minor, non significant, inhibitory action on acid gastric secretion stimulated by maximal doses of pentagastrin, while showing no differences against the group without administration of domperidone.