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Biomedical subjects

J Scharf

Publications and source records attributed to J Scharf.

At least 73 records · Page 4Linked to original sources
PubMed1988

Autoregulatory capacity and the effect of isovolemic hemodilution on local cerebral blood flow.

The effect of isovolemic hemodilution with dextran 40 on local cerebral blood flow was measured in eight cats by means of the hydrogen clearance technique. Under normotension the decrease of hematocrit from 35% to 25% causes a sudden increase of up to 30% in local cerebral blood flow. After lowering the mean arterial blood pressure from 140 to 80 mm Hg, hemodilution did not alter cerebral blood flow significantly. From this observation it is concluded that the increase of cerebral blood flow following hemodilution is caused by compensatory vasodilatation and not by reduction of blood viscosity. This could imply that hemodilution cannot improve blood flow in areas of impaired autoregulation.

Animals↗
PubMed1988

Localization of denatured enzyme molecules in rat lenses.

Immunohistochemical localization of altered enzyme molecules was detected by the use of antibodies to denatured enzymes (ADE) conjugated with fluorescein. Denatured aldolase, glucose 6-phosphate dehydrogenase and superoxide dismutase are mostly located in the subcortical region and in the nucleus of the rat lens. In the nuclear fibres the enzyme is located near the membrane of the fibres. This study provides additional evidence that altered enzyme molecules accumulate in the lens, and indicates their exact localization. ADE antibody can distinguish between inactive enzyme molecules and active ones, using immunohistochemical techniques.

Animals↗
PubMed1987

Defective superoxide-dismutase molecules accumulate with age in human lenses.

The specific activity of superoxide dismutase (SOD) in human transparent lenses declines as a function of age. Immunotitration using monospecific antibodies showed that, with increasing age, lenses exhibit an accumulation of catalytically inactive, but antigenically reactive, enzyme molecules. Antiserum produced against denatured enzyme removed the inactive molecules from the lens homogenates without affecting the enzyme activity. These aberrant molecules are at least partially denatured and are totally devoid of catalytic activity.

Adolescent↗
PubMed1987

Left ventricular volume during supine exercise: importance of myocardial scar in patients with coronary heart disease.

Existing studies suggest that exercise-induced ischemia produces an increase in left ventricular end-diastolic volume; however, all of these studies have included patients with previous myocardial infarction. To test whether the end-diastolic volume response to exercise is related to the extent of myocardial scar, the results of gated radionuclide supine exercise tests performed on 130 subjects were reviewed. The patient group comprised 130 subjects were reviewed. The patient group comprised 130 men aged 35 to 65 years (mean +/- SD 52 +/- 5) with documented coronary heart disease. The extent of myocardial ischemia and scar formation was assessed by stress electrocardiography and thallium-201 scintigraphy. Patients were classified into three groups on the basis of left ventricular end-diastolic volume response at peak exercise: group 1 (n = 72) had an increase of end-diastolic volume greater than 10%, group 2 (n = 41) had a change in end-diastolic volume less than 10% and group 3 (n = 17) had a decrease in end-diastolic volume greater than 10% (n = 17). At rest there was no significant difference among groups in heart rate, systolic blood pressure, end-diastolic (EDVrest) or end-systolic volumes or ejection fraction (p greater than 0.05); however, at peak exercise the end-systolic volume response was significantly greater for group 1 (p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Chemical analysis of whole saliva in Sjögren's syndrome.

In some studies, but not in all, abnormally high concentrations of salivary Na+, K+, and IgA have been found in patients with Sjögren's syndrome (SS). The lack of agreement between various reports might be due to the different ways in which saliva was collected. Some analysed stimulated parotid or whole saliva, whereas others used unstimulated saliva. In this study, therefore, the rate of flow and Na+, K+, and IgA levels in unstimulated and stimulated whole saliva in normals and in rheumatoids with and without SS have been determined. The results confirmed significantly raised levels of Na+, K+, and IgA in unstimulated whole saliva in SS. In response to stimulation there was marked decrease in Na+, K+, and IgA levels, whereas normally, as shown by the other two groups, there is an increase in Na+, no change in K+, and a mild decrease in IgA. As a result, the differences between SS and normals became much less significant (K+, IgA) or were even completely obliterated (Na+). The abnormal response of SS to stimulation may be partially explained by the initially low rate of flow and by the extremely high IgA levels. Thus chemical analysis of unstimulated whole saliva is much more sensitive than analysis of stimulated whole saliva in the detection of salivary gland involvement in SS.

Citrates↗
PubMed1986

G6PD molecules devoid of catalytic activity are present in the nucleus of the rat lens.

The specific activity of glucoso-6-phosphate dehydrogenase (G6PD) in the rat lens declines as a function of animal age. G6PD activity could be found only in the cortex of the lens. Previous work showed that antibodies against the 'native' form of G6PD could not recognize any cross-reacting material (CRM) in the lens. It was speculated that this could be due either to disappearance of G6PD from the nucleus by degradation or by alterations of the molecules which resulted in the loss of their antigenic determinants. In order to investigate this question, an antibody was prepared against denatured G6PD. This antibody did not interact with 'native' (active) forms of the enzyme; it was shown, however, to recognize antigenically cross-reactive but catalytically inactive intact G6PD molecules in the nucleus of the lens. This finding suggests that altered enzyme molecules are at least partially denatured and accumulate in the lens without being further cleaved proteolytically.

Aging↗
PubMed1986

Superoxide dismutase molecules in human cataractous lenses.

Specific activity of superoxide dismutase (SOD) in cataractous lenses was examined. Immunoprecipitation with monospecific antibodies showed an accumulation of catalytically inactive, but antigenically reactive enzyme molecules in lenses with various types of cataracts. The inactive enzyme molecules can be demonstrated in all kinds of cataracts, including dense, mature cataracts with very low or nondetectable enzyme activity. In cataracts from diabetic patients, the mean enzyme activity was higher than in nondiabetic patients. This was especially marked in nuclear cataracts, in which the specific activity of SOD was higher than in similar cataracts from nondiabetics.

Cataract↗
PubMed1986

Immunogenetics of juvenile chronic arthritis in Israel.

Typing for HLA-A,B,C and DR antigens was performed in 61 Israeli patients with juvenile chronic arthritis (JCA) and in 120 unrelated controls. No significant associations were apparent in the overall patient group. DR5 was significantly increased in the non-Ashkenazi patients with pauciarticular onset of disease. The only three DRw8 positive patients in the study had pauciarticular onset. DR5 and DRw8 were found in 9 of 10 patients with age of onset less than 3 years. Increased frequencies of Bw50 and Cw6 were observed in patients with systemic onset. Typing for properdin factor (Bf) and glyoxylase (GLO) was carried out in 45 and 50 of the patients, respectively. No associations with alleles of the complement Bf system or the HLA linked GLO system were evident. The confirmation in the ethnically distinct Israeli population of the previously described association of DR5 with pauciarticular JCA suggests that this gene may be closely related to the disease susceptibility gene.

Adolescent↗
PubMed1985

3-Methylglutaconic and 3-methylglutaric aciduria in a patient with suspected 3-methylglutaconyl-CoA hydratase deficiency.

A girl suffering from marked muscular hypotonia, severe statomotor and mental retardation, bilateral optic atrophy with chorioretinal degeneration, convulsions and a moderate compensated metabolic acidosis is described. Screening for metabolic disorders revealed massive 3-methylglutaconic with 3-methylglutaric aciduria leading to the tentative diagnosis of 3-methylglutaconyl-CoA hydratase deficiency. Metabolite excretion was correlated with variation of leucine intake. 3-methyl-3-hydroxyglutaryl-CoA lyase activity in cultured fibroblasts was normal. The suspected metabolic defect was not demonstrable in cultured skin fibroblasts, however.

Acidosis↗
PubMed1984

A randomized trial of exercise training in patients with coronary heart disease.

In order to determine whether or not regular exercise could alter myocardial perfusion or function, we randomized 146 male volunteers with stable coronary heart disease to either a supervised exercise program (n = 72) or to a usual care program (n = 74). Subjects underwent exercise tests initially and one year later. Significant differences between the two groups included improved aerobic capacity, thallium ischemia scores, and ventricular function in the exercise intervention group. It was not possible to classify the conditions of patients as to the likelihood of improvement or deterioration. This study demonstrated changes in myocardial perfusion and function in a select group of middle-aged men with coronary heart disease who underwent a medically appropriate exercise program lasting one year, but these changes were relatively modest.

Adult↗
PubMed1984

Glyceraldehyde 3-phosphate dehydrogenase activity in rat and human lenses and the fate of enzyme molecules in the aging lens.

The specific activity of the enzyme glyceraldehyde 3-phosphate dehydrogenase declines as a function of age. Immunotitration with monospecific antibodies demonstrated that with age there is an increase of catalytically defective, but antigenically reactive enzyme molecules in the lens. Antiserum, produced against denatured enzyme, removed the inactive molecules from lens homogenates, without effects on the levels of enzyme activity. These studies suggest that inactive enzyme molecules in aging lenses are totally devoid of catalytic activity, and are at least partially denatured.

Adult↗
PubMed1982

[Treatment of glycogenosis type III with total parenteral nutrition, continuous intragastric infusion and D-thyroxine].

A 4-year-old patient with glycogenosis type III suffered from hypoglycemic attacks during the night and from an enormous hepatomegaly. The latter was the cause of a life-threatening respiratory insufficiency. Shrinkage of the liver size was an urgent necessity. The beneficial influences of total parenteral nutrition, continuous intragastric infusion during the night, and of D-tyhroxin are described.

Blood Glucose↗