Stapedius reflexometry: A diagnostic test of myasthenia gravis

Contraction of the stapedius muscle can be measured by electroacoustic impedance bridge. Muscle weakness and easy fatiguability which are cardinal features of myasthenia gravis (MG) are manifested by increased threshold and early decay of the stapedius reflex. This can be used as an objective test in the diagnosis of myasthenia gravis. Stapedius reflex was measured using Madsen Zo72 electroacoustic impedance bridge in 10 patients with myasthenia gravis and in an equal number of controls. The test was done before and 30 min after intramuscular injection of neostigmin.All patients with myasthenia gravis showed an elevated reflex threshold and 5 patients showed reflex decay. These findings reverted to normal after neostigmin injection. Stapedius reflexometry is a simple objective test for the diagnosis of myasthenia gravis.     

Effects of phenol and dinitrophenol on acid and alkaline phosphatases in tissues of a fish (Notopterus notopterus)

Specimens of a fresh water fish,Notopterus notopterus were exposed to either phenol (12.56 mg/L), dinitrophenol (1.34 mg/L), or a mixture of the two (6.28 mg phenol + 0.67 mg dinitrophenol/L) for 72-hr. Surviving fish were sacrificed at 24-, 48-, and 72-hr after exposure, and tissue samples were taken for determining the acid phosphatase and alkaline phosphatase activities. Phenol, dinitrophenol, and mixtures of both, inhibited the activity of both enzymes in the kidney, heart, brain, gills, muscles, stomach, intestine, and pyloric caeca. Dinitrophenol exerted more inhibition than phenol. In general, mixtures of phenol and dinitrophenol are somewhat more effective than either compound alone in the inhibition of enzyme activities.     

Expression of FBJ-MSV oncogene (fos) product in bacteria

The protein predicted from the DNA sequence of the FBJ murine osteosarcoma virus (FBJ-MSV) onc gene (v-fos) was expressed in Escherichia coli under the control of the tryptophan operon regulatory region. The 381-amino acid protein was identified by synthesis in minicells isolated from bacteria containing the expression vector plasmid. A 52,000-Da protein was made in these minicells, along with the proteins encoded by the beta-lactamase gene present on the expression vector plasmid. Synthesis of the 52K protein was repressed in trpR+ E. coli minicells in the presence of tryptophan, whereas the protein was synthesized under the same conditions in trpR- (derepressed) minicells. The beta-lactamase proteins, however, were synthesized under both conditions. The synthesis of the viral protein, therefore, was directed by the trp operon promoter. The tryptic peptide map of the 52K bacterial protein labeled with [35S]methionine was compared to that of the 35S-labeled protein immunoprecipitated from FBJ-MSV transformed rat cells using tumor-bearing rat sera. The peptide map of the p55 protein, previously identified as a candidate transforming protein in FBJ-MSV transformed cells, matches exactly that of the bacterial 52K protein. The eukaryotic cell protein, however, differs slightly in electrophoretic mobility in SDS gels, most likely due to post-translational modification which does not occur in bacteria.     

Haemodynamic dose-response effects of intravenous amrinone in left ventricular failure complicating acute myocardial infarction

The haemodynamic dose-response effects of intravenous amrinone were measured in 16 male patients, aged 40-65 years, with radiographic and haemodynamic evidence of left ventricular failure 4-18 h after acute myocardial infarction. After a l-h control period to confirm stable haemodynamic baseline variables, patients were randomised to either low-dose (200-400-800 micrograms/kg/h) or high-dose (800-1600-3200 micrograms/kg/h) intravenous amrinone. Each of the three infusions was given consecutively over 30 min (total infusion time 90 min) in each group, and haemodynamic measurements were made at the end of each infusion step. No arrhythmias or other untoward side effects, including haematological changes, were observed during the infusions. In both groups, intravenous amrinone reduced the pulmonary artery-occluded pressure (PAOP) (p less than 0.01), increased the cardiac output (p less than 0.05), and reduced the systemic vascular resistance (p less than 0.05). The reductions in PAOP and systemic arterial diastolic pressure and the increase in heart rate were directly dose-related, but the changes in cardiac output and systemic vascular resistance were not. These results suggest that peripheral vasodilation, particularly of venous capacitance vessels, as well as positive inotropic stimulation, may play a role in the haemodynamic changes induced by intravenous amrinone in acute ischaemic left ventricular failure.     

Inhibition of 7,12-dimethylbenz(a)anthracene- and N-nitrosomethylurea-induced rat mammary cancer by dietary flavonol quercetin

The effects of dietary supplementation of flavonol quercetin on both 7,12-dimethylbenz(a)anthracene (DMBA)- and N-nitrosomethylurea-induced mammary cancer in female Sprague-Dawley rats were determined. Quercetin diet was started 1 wk before intragastric instillation of DMBA (65 mg/kg of body weight) or i.v. injection of N-nitrosomethylurea (50 mg/kg of body weight) and was continued during the entire period (20 wk) of the experiment. Dietary quercetin inhibited both the incidence and the number of palpable rat mammary tumors; rats fed on 2% quercetin had 25% less incidence of mammary cancer, while the average number of mammary tumors per rat was reduced by 39% at 20 wk post-DMBA administration compared to animals on a control diet. In a separate experiment, a 5% quercetin diet elicited a greater inhibitory effect on the induction of rat mammary tumors by DMBA than was observed with a 2% quercetin diet. The inhibitory effect of quercetin on mammary tumor incidence in rats on 2% and 5% diets and on tumor multiplicity in animals on a 5% diet was statistically significant (P less than 0.05). In addition, the risk of the development of a palpable tumor (as determined by the nonparametric estimate of the hazard function) in the quercetin-fed group was lower than the group on control diet throughout the course of the experiment. Furthermore, 5% dietary quercetin significantly inhibited (P less than 0.05), although to a lesser extent than observed in DMBA-induced tumor formation, both the incidence and the number of palpable mammary tumors per rat induced by N-nitrosomethylurea. Dietary quercetin did not elicit any detectable sign of toxicity. The gain in body weight in rats on the quercetin diet and the quantity of diet consumed per rat per week were similar to those for rats on the control diet.