Search PubMed⌕ Search

Biomedical subjects

G Keren

Publications and source records attributed to G Keren.

At least 163 records · Page 9Linked to original sources
PubMed1984

Can pseudomonas infection in experimental animals mimic Kawasaki's disease?

Experiments aimed at producing a model of Kawasaki's disease by injecting animals intraperitoneally with Pseudomonas bacilli are described. Injection of large numbers of bacilli into mice caused rapidly fatal sepsis. With appropriate numbers of organisms, some mice died within 3 days, most remained healthy, while in some an inapparent chronic disease developed. Positive blood cultures were occasionally obtained 4-17 weeks after the slow infection. An alcohol-precipitable polysaccharide, which could be measured by Roe's procedure for levan, was found in 20% of the experimentally infected mice. We suggest that this substance was partly responsible for the course of the infection. Severe vasculitis with little acute inflammatory reaction and carditis with coronary aneurysms were often obtained by injecting mice and guinea-pigs with supraliminal doses of bacilli at the same time as their immune system was impaired by treatment with either nitrogen-mustard or cyclophosphamide. We suggest that pseudomonas infection in immunologically deficient animals may mimic Kawasaki's disease and that a similar mechanism may operate in the natural form of the disease in children.

Animals↗
PubMed1984

Studies on the possible mechanisms of lidoflazine arrhythmogenicity.

Lidoflazine is a calcium channel blocking agent that is effective and safe in the treatment of angina pectoris, but has been reported to be associated with sudden death when administered for the treatment of supraventricular arrhythmias. Studies were performed in dogs to determine if lidoflazine caused a rise in serum digoxin concentration that could cause arrhythmias or if it was directly arrhythmogenic. Dogs received chronic injections of digoxin and then digoxin in combination with lidoflazine. No increase in digoxin concentration was found. Dogs also underwent programmed electrical stimulation while not receiving medications and then after incremental doses of lidoflazine administered intravenously. Lidoflazine did not cause spontaneous ventricular tachycardia and did not lower the threshold of ventricular tachycardia induction. Combined administration of lidoflazine and digoxin did not facilitate arrhythmia induction. These studies do not support a digoxin-lidoflazine interaction or a direct arrhythmogenic action of lidoflazine.

Animals↗
PubMed1984

Ventricular tachycardia induced by slow ventricular pacing.

Two patients are described, in whom ventricular pacing at physiological rates (72 to 75 beats/min) repeatedly induced ventricular tachycardia (VT). In the first patient, pacing was required because of complete atrioventricular block following an inferior and right ventricular (RV) myocardial infarction. VT developed during RV posterobasal pacing, but not during RV outflow tract pacing at similar rates. The second patient had a postinfarction left ventricular aneurysm and was paced because of amiodarone-induced sinus node dysfunction. VT developed when the rate of ventricular pacing was similar to that of the sinus rate. We conclude that in patients whom VT is induced at physiological rates of pacing, the following factors may be involved in the triggering of VT: the rate of pacing, the site of ventricular stimulation; and the administration of antiarrhythmic drugs. Early recognition of these factors, which may facilitate reentry by aggravating previously existing intraventricular conduction disturbances, is imperative for the effective management of the arrhythmia.

Aged↗
PubMed1984

Comparison of the effect of various stimuli on the leishmaniacidal capacity of human monocytes in vitro.

Leishmania organisms are obligate intracellular parasites of mammalian mononuclear phagocytes in vivo. In order to study the interactions of these parasites and mononuclear phagocytes, we have used a model of infection of Leishmania major in human monocytes in vitro. The presence of intracellular parasites did not alter the normal secretion of lysozyme or result in increased secretion of prostaglandin E2 (PGE2) or superoxide anion by the monocytes. Addition of concanavalin A (Con A), which binds to a specific membrane receptor, zymosan particles or endotoxin to infected monocyte monolayers, resulted in the expected increase in PGE2 secretion. In addition, the production of superoxide by infected monocytes treated with phorbol myristate acetate was not different from control uninfected cultures. Despite this evidence of biochemical activation, neither endotoxin, zymosan nor Con A had any parasiticidal effect on the intracellular parasites. In contrast, Con A-induced lymphokines from human mononuclear cells resulted in an increased killing of the intracellular amastigotes. These studies have shown that the induction of leishmaniacidal capacity of human monocytes is dependent on the type of stimulus used to induce activation.

Cells, Cultured↗
PubMed1983

External inspiratory resistance of protective respiratory devices: effects on physical performance and respiratory function.

Twenty subjects wearing protective respirators were studied during submaximal exercise (80% of VO2max) on a treadmill. The protective devices were fitted with canister filters of low expiratory resistance and different inspiratory resistances: (0.3, 1.8, 2.8, 3.4, 3.9, and 4.6 cm H2O X sec/liter). The effect of inspiratory resistance on physical endurance, various physiological parameters, and subjective sensations was examined. With the increase in inspiratory resistance, a significant decrease in physical performance, decrease in tidal volume, increased ratio of inspiratory to expiratory time, increased peak inspiratory pressure, and increased CO2 retention were observed. The difficulty in inspiration correlated significantly to inspiratory resistance and seems to be the main reason for cessation of the effort. No acceptable upper limit for the inspiratory resistance of the canister filters was found. Any decrease in the inspiratory resistance of the mask's filter enhanced endurance and performance.

Adult↗
PubMed1983

Mucocutaneous lymph node syndrome (Kawasaki dIsease) in Israel. A review of 13 cases: is pseudomonas infection responsible?

In this report the clinical, laboratory and histopathological findings of 13 children with Mucocutaneous Lymph Node Syndrome (Kawasaki disease; MCLS) are reviewed. This is the first report of a series with a description of the clinical findings as well as pathological findings in patients from Israel. Pseudomonas infection appeared to be the underlying cause of both the clinical symptoms and the pathological changes of some (or all) cases of Kawasaki disease.

Adolescent↗
PubMed1983

Pulmonary arterio-venous fistulae in hepatic cirrhosis.

Cyanosis, clubbing, and arterial oxygen desaturation may occur in patients with liver disease, and are attributed to the presence of pulmonary or peripheral arterio-venous shunting. Cardiac catheterisation and angiocardiography in a patient with a normal heart did not demonstrate the presence of abnormal arterio-venous anastomoses. Pulmonary shunting was proved when intravenous technetium-labelled macroaggregated albumin, normally held up in capillary networks, was passed quickly through the lungs and immediately detected in high systemic blood flow organs. The opening of peripheral and pulmonary anastomoses in patients with liver disease may be owing to the presence of a vasodilatory substance such as ferritin, which was found to be abnormally increased in the patient's blood.

Adolescent↗
PubMed1983

The cimetidine-lidocaine interaction.

Lidocaine is a widely used antiarrhythmic agent whose plasma clearance varies with changes in hepatic blood flow. Cimetidine, an H2-receptor antagonist, has been shown to decrease hepatic blood flow. To ascertain whether cimetidine affected serum lidocaine concentration, we studied 21 patients receiving lidocaine infusions and divided them into two groups. Fifteen patients received cimetidine, 300 mg every 6 hours, in addition to lidocaine; six patients received only lidocaine. In 14 of the 15 patients receiving both lidocaine and cimetidine, a rise in serum lidocaine levels was seen, whereas no change was noted in the control group. Six of the 15 patients were found to have levels in the toxic range and two had symptoms. An additional three patients on lidocaine received diphenhydramine, an H1-receptor antagonist. No elevation in serum lidocaine levels was noted after administration of diphenhydramine. We conclude that there exists an interaction between lidocaine and cimetidine and that the rise in serum lidocaine levels may be mediated by cimetidine's inhibition of the H2 receptor.

Cimetidine↗
PubMed1983

The penetration of gentamicin into the vitreous humor in man.

Twenty-two patients received gentamicin intramuscularly or subconjunctivally 35-220 min prior to undergoing ocular surgery. There were no detectable gentamicin levels in the vitreous humor of patients who received the drug systemically. Of the patients who received gentamicin subconjunctivally, three quarters had no detectable gentamicin levels, only three of these patients had therapeutic concentrations in their vitreous humor. These results confirm kinetic drug studies performed in animals in which low or absent vitreal gentamicin levels were observed following systemic and subconjunctival administrations. It is suggested that intravitreal injection of aminoglycosides is required in the treatment of bacterial endophthalmitis.

Adult↗
PubMed1982

March myoglobinemia: a hazard to renal function.

Serum muscle enzyme levels, myoglobin levels, and renal function were measured in a group of 20 army recruits who had volunteered for a prolonged period of primary, specially designed, gradual training. Blood samples were taken before training and before and after each hike. Levels of serum myoglobin, creatinine phosphokinase, lactic dehydrogenase, and SGOT indicated muscle injury. Levels of urea creatinine, and uric acid and creatinine clearance evaluated renal function. Substantial elevation of muscle enzyme levels and persistent myoglobinemia were observed throughout the study. A highly significant decrease in creatinine clearance was demonstrated. After the last hike, the mean creatinine clearance was 70.41 mL/min, which is notably lower than the value at the beginning of the study. Prolonged physical exercise induces muscular damage, as evidenced by a rise in myoglobin and enzyme levels. Continuous muscle injury induces persistent myoglobinemia, a probable hazard to renal function.

Acute Kidney Injury↗
PubMed1982

The trisomy 4p syndrome: a case report.

Partial trisomy of the short arm of chromosome 4 is considered to be a rare chromosomal disorder. Its clinical and dermatoglyphic features tend to make it a clinically recognizable syndrome. This paper describes a 2 year-old female child with the characteristic findings of frontal bossing, deep-set eyes, broad nasal bridge giving the appearance of hypertelorism, wide nares, midfacial hypoplasia, large dysplastic ears, prognathism and various hand and foot malformations. Chromosomal studies showed her to be trisomic for the distal two-thirds of the short arm of number 4. The etiology of this chromosomal aberration in most instances is unknown, but may occur as a result of an unbalanced translocation in one of the parents as in the case reported here.

Child, Preschool↗