Pyridostigmine bromide protection against acetylcholinesterase inhibition by pesticides.

Pyridostigmine bromide (PB) has been used to protect soldiers from the toxic effects of soman, a chemical warfare agent. Recent research shows that pyridostigmine bromide protects a significant percentage of acetylcholinesterase in isolated human intercostal muscle. Findings presented here indicate that red blood cell acetylcholinesterase is similarly protected by pyridostigmine bromide from the action of diisopropyl fluorophosphate and several organophosphate pesticides including chlorpyrifos-oxon, diazinon-oxon, and paraoxon, but not malaoxon, using the bovine red blood cell as a subject.

Influence of 3-methylcholanthrene on the redox-state of liver and red muscles in vivo.

It was observed, that following an injection of 3-methylcholanthrene (MC), the tissue redox-state potential is modified expressively both in liver and in red muscles. In the liver in the first day an oxidosis develops, which is followed by redosis, but in the muscle a redosis can be observed already in the first day. It is a meaningful fact, that MC influences biochemical processes in the early phase of its effect not only in the liver but also in the red muscle.

Opposite effects of methylene blue and ascorbate on lipid peroxidation in muscles. Correlation with the redox state. I. Experiments on satisfied frogs.

Homogenates of heart, stomach and rectus abdominis muscles of the frog have shown different degrees of malondialdehyde (MDA) formation. MDA content was highest in heart, and lowest in stomach musculature. The resultant tissue redox-state potential (RSP) and redox potential (E'0) in homogenates determined potentiometrically also showed differences with opposite signs in relation to MDA levels.

The free radical mechanisms in beta-carotene induced gastric cytoprotection in HCl model.

The aims of our experiments were to clear up the possible correlations between the free radical mechanisms and the gastric cytoprotection of beta-carotene on HCl-induced gastric mucosal lesions. The beta-carotene was intragastrically given in doses of 1 and 10 mg/kg and 30 min. later 1 ml 0.

A unique cell type in the lung--the Clara cell (the non-ciliated bronchiolar epithelial cell).

The non-ciliated bronchiolar epithelial cells (the Clara cells) are found most frequently in the distal conducting airways, but they are found throughout the tracheobronchial tree of different mammalian species. According to recent data, the main functions of the Clara cells can summarized as (1), the secretion of certain components of the extracellular bronchiolar lining layer (2), metabolism and detoxification of xenobiotics and other toxic compound (3) and participation in the renewal process of the bronchiolar epithelium. The main goal of this paper is to collect and discuss some of the general features of Clara cells from a functional-morphological point of view, and their possible role in pathological alterations of the lung especially in the pathogenesis of lung tumours originated from Clara cells.

The interrelationships between the lipid peroxidation, superoxide dismutase activity, development of gastric H+ secretion and gastric mucosal damage produced by intragastric administration of aspirin in pylorus-ligated rats.

Gastric mucosal damage of pylorus-ligated rats was induced by the intragastric administration of aspirin at 200 mg/kg at the time of ligation. The animals were sacrificed at 0, 1, 2, 3, and 4 h after the treatment. The gastric lesions (ulcers) were counted and their severities were calculated, and the volume of gastric secretion and the H+ output were measured.

Effect of 3-methylcholanthrene on the protein composition of heterogeneous nuclear ribonucleoprotein particles in developing rat liver.

Nine-day-old rats were treated with a single 100 mg/kg body weight intraperitoneal dose of 3-methylcholanthrene (3-MC). 24, 48, 72 and 120 h later the protein composition of the heterogeneous nuclear ribonucleoprotein particles derived from the liver was analysed. The analysis was performed by urea-sodium dodecyl sulphate polyacrylamide gel electrophoresis.

Lipid peroxidation in lung of rats exposed to hyperoxic, hypoxic and ischemic effects.

Rat experiments were undertaken to describe the range of the endogenous lipid peroxidation (measured by formation of malondialdehyde [MDA] in lung tissue) and to analyze the effects of hyperoxic, hypoxic and ischemic influences. The acute hyperoxia caused a moderate increase in lipid peroxidation. The MDA formation in lungs of rats was perceptibly higher in low oxygen environment, while the highest values were found in ischemic lungs.

Comparison of heterogeneous nuclear ribonucleoprotein particles of the developing rat liver.

hnRNP monoparticles were isolated from livers of newborn (1 day), 7, 10, 11, 14, 21, 28 days old and adult rats, and their sedimentation properties, buoyant densities and protein composition were compared. There were observable differences neither in sedimentation nor in buoyant density among the particles isolated from livers of rats of different ages. The hnRNP particles derived from every stage of ages sedimented in the 30-50S zone of sucrose gradient with a peak at about 38S.

Nucleolar activity after 3-methylcholanthrene treatment of rat liver cells studied by silver staining procedure.

The influence of a single dose of 3-methylcholanthrene (3-MC) was studied in nucleoli of young rat liver cells by means of conventional and ultracytochemical methods. The nucleolar activity was stimulated in our experimental conditions: the appearance of the fibrillar centres in the liver cell nucleoli as well as the silver staining protein content of the fibrillar centres and the dense fibrillar component were increased by 3-MC. The results suggest that the activity of ribosomal genes was increased following 3-MC treatment.

Interrelationships between the gastric cytoprotective effects of vitamin A and beta-carotene and the gastric mucosal superoxide dismutase activity in rats.

Gastric mucosal damage was produced in rats by the intragastric administration of 96% ethanol or 0.6 M HCl, according to the method of Robert et al. Vitamin A or beta-carotene, in doses of 10 mg/kg, given intragastrically 30 min before the administration of the necrotizing agents.

The interrelationships between the development of ethanol-, HCl, NaOH and NaCl-induced gastric mucosal damage and the gastric mucosal superoxide dismutase activity in the rats.

Gastric mucosal damage was produced by intragastric administration of 96% ethanol, 0.6 M HCl, 0.2 M NaOH or 25% NaCl.

Membrane perturbations in myocardium: oxygen radicals mediate injuries in experiments.

Experiments were undertaken on rats and dogs to study the range of endogenous lipid peroxidation (measured by formation of malondialdehyde in heart tissue) and to analyse the effects of hyperoxic, hypoxic and ischaemic influences. The acute hyperoxia caused a moderate increase in lipid peroxidation. The malondialdehyde formation was perceptibly higher in hypoxia, while the highest values were found in ischaemic hearts.

Interrelationships between the development of the gastric cytoprotective effects of prostacyclin, atropine, cimetidine and the gastric mucosal superoxide dismutase activity in rats.

Gastric mucosal damage was produced by the intragastric administration of 96% ethanol or 0.6 M HCl. The cytoprotective doses of prostacyclin (PGI2) (5 micrograms/kg), atropine (0.

Structural characterization of nuclear poly(A)-protein particles in rat liver.

Poly(A)-protein particles were prepared from rat liver nuclear extract after digestion with pancreatic ribonuclease and ribonuclease T1 by sucrose gradient centrifugation. The particles were sedimented in a range of 9-23S with a peak at 16S. The particles isolated in this manner were 99-100% resistant to further pancreatic ribonuclease treatment and contained more than 90% adenylic acid.

Lipid peroxidation in the membrane damaging effect of silica-containing dust on rat lungs.

Rats were injected intratracheally with a single dose of 50 mg silica (DQ-12) suspended in 0.5 ml saline. The animals were sacrificed at 3, 6, 12 and 21 days following exposure, and the rate of lipid peroxidation as well as the activities of superoxide dismutase and catalase were measured in the lung tissue.

Influence of 3-methylcholanthrene on liver nucleolar and nucleoplasmic activities of protein kinases and RNA polymerases.

The experiments were designed to investigate some details of the action of 3-methylcholanthrene (3-MC) on the regulation of transcription. After a single intraperitoneal dose of 3-MC a significant increase in the activities of both nucleolar and nucleoplasmic protein kinases in hepatic cells of young rats was found. The maximal stimulation took place 24 hr after the administration of 3-MC and the extent of activation was much greater in the nucleolar fraction.

Structural characterization of polysomal poly(A)-protein particles in rat liver.

Poly(A)-protein particles were prepared from rat liver polyribosomes, washed with 0.5 M KCl or unwashed, after digestion with pancreatic ribonuclease and ribonuclease T1 by two successive rounds of sucrose gradient centrifugation. The particles were sedimented in a range of 5--13 S with a peak at about 9 S.

Studies on the structure of rat liver messenger ribonucleoprotein. II. Non-poly(A) RNase resistant fragments and electron microscopic appearance of mRNP.

Partially fragmented 12-21S rat liver messenger ribonucleoprotein (mRNP), labelled either with [3H]-orotic acid or [3H]-adenine was treated with 5 (micrograms/ml or 0.1 microgram/ml pancreatic ribonuclease (EC 3.1.

Studies on the structure of rat liver messenger ribonucleoprotein. I. Isolation and characterization.

Messenger ribonucleoprotein (mRNP) was released from 0.5 M KCl washed rat liver polyribosomes after mild pancreatic ribonuclease (EC 3.1.

Effect of 3-methylcholanthrene on RNA polymerase and protein kinase activities and on the nuclear ultrastructure of rat liver.

The polycyclic aromatic hydrocarbon 3-methylcholanthrene (3-MC) is a well known inducer of the microsomal mixed function oxidase enzyme system in rat liver cells. It seems probable that the inductive action of 3-MC is realized, at least partly, at the transcriptional level of protein synthesis regulation. The present experiments indicated that in the liver of young rats there was a significant alteration in the activities of nucleolar as well as nucleoplasmic protein kinase and RNA polymerase enzymes during the first days of exposure to a single dose of 3-MC.