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Biomedical subjects

I Tamir

Publications and source records attributed to I Tamir.

At least 55 records · Page 3Linked to original sources
PubMed1984

Isolation and characterization of an intermediate steroid metabolite in diosgenin biosynthesis in suspension cultures of Dioscorea deltoidea cells.

The aglycon form of the steroidal sapogenin furost -5-ene-3 beta, 22,26-triol, 3 beta- chacotrioside 26 beta-D-glucopyranoside was isolated from cell suspension cultures of Dioscorea deltoidea and its molecular structure was determined by mass spectrometry and 1H and 13C n.m.r. spectroscopy. From kinetic studies and incorporation experiments with [1-14C]acetate it was concluded that the steroidal compound (in the glycoside form) is an intermediate in vivo in diosgenin biosynthesis. It accumulated in growing cells of D. deltoidea and was metabolized to diosgenin (in the glycoside form, i.e. dioscin ) in non-dividing cells.

Acetates↗
PubMed1984

Polymorphonuclear leukocyte-associated antigenemia in measles: demonstration and significance.

An indirect immunoperoxidase technique was used for the identification of measles virus (MeV) antigen in routinely prepared peripheral blood smears. Characteristic brown immunoperoxidase staining was present in the polymorphonuclear (PMN) leukocytes in 25 of 31 children during the exanthematous stage of measles. No peroxidase staining was seen on peripheral blood smears in any of 9 children convalescing from measles or in 9 children with upper respiratory tract infections ( URTI ) without exanthema. These findings were confirmed by control studies and were reproduced by immunofluorescent staining. The data suggest that MeV antigen is localized in the PMN leukocytes during the acute stage of measles infection, and may be connected to phagocytosis of viral antigenic material by PMN leukocytes. The technique described has potential for rapid laboratory diagnosis of measles and, possibly, of other viral infections during the acute stage and before measurable amounts of antibodies are produced.

Acute Disease↗
PubMed1983

Breast milk and adipose tissue fatty acid composition in relation to maternal dietary intake.

The fatty acid (FA) relative concentration (g/100g) of human milk triglyceride (TG) was compared to that of adipose tissue (AT). A high concentration of linoleic acid (C-18:2) was present in AT, probably reflecting long term high linoleic acid dietary intake. Linoleic acid was slightly lower in colostrum and transitional milk. No difference in C-18:2 relative concentration was seen between AT and human milk obtained 6 weeks post-partum. Marked short-term dietary modification in linoleic acid intake of the mother, 6 weeks post-partum, did not result in changes in C-18:2 relative concentration of human milk. In spite of measured marked intradiurnal variability in C-18:2 intake, human milk TG FA relative concentration remained remarkably constant. It is suggested that human milk TG FA composition reflects, mainly, the composition of AT. With the increased dietary intake of polyunsaturated fat in many populations, high levels of linoleic acid in human milk are to be expected. The intake of this fatty acid may exceed the suggested daily allowance and thus cause harmful effects, particularly in preterm infants.

Journal Article↗
PubMed1983

Cerebral perfusion pressure in central nervous system infections of infancy and childhood.

Central nervous system infections may be complicated by development of severe brain edema, which can be a significant factor in mortality and morbidity. Increased intracranial pressure can cause additional damage to the central nervous system by impairment of cerebral blood flow, which is dependent on cerebral perfusion pressure. A reduction of cerebral perfusion pressure, caused by elevation of intracranial pressure, may cause cerebral ischemia. We studied cerebral perfusion pressure in 17 patients, ages 45 days to 11 years, with severe central nervous system infections and who were in deep coma. Meningitis was diagnosed in 64.7%, and encephalitis in 29.4%. The patients who survived (64.7%) did not differ significantly from those who died (36.5%) in severity of disease and maximal intracranial pressure during the course of the illness. A striking difference in minimal cerebral perfusion pressure recorded was found between survivors and nonsurvivors: all patients with minimal cerebral perfusion pressure greater than 30 mm Hg survived, whereas those with lower pressure died. In survivors, cerebral perfusion pressure could be maintained adequately by reduction of intracranial pressure, but nonsurvivors developed noncompliance of brain tissue, and cerebral perfusion pressure could not be maintained at levels that ensure adequate cerebral blood flow, resulting in cerebral ischemia and death. Continuous monitoring of mean arterial blood pressure and intracranial pressure in children with severe central nervous system infections will enable rapid diagnosis and initiation of treatment when cerebral perfusion pressure is reduced to critical levels. Such treatment might improve the prognosis.

Blood Pressure↗
PubMed1983

Selected nutrient intakes of free-living white children ages 6-19 years. The Lipid Research Clinics Program Prevalence Study.

We report energy intake and selected nutrient intakes-protein, fat (total, saturated, and polyunsaturated), carbohydrate (total, starch, and sucrose), and cholesterol-for 1251 white children ages 6-19 years. The data were obtained, by means of a 24-h dietary recall, from children who were randomly selected from the North American populations studied by the Lipid Research Clinics Program. Females (N = 584) consumed about 2000 kcal daily, an intake that remained relatively constant throughout the age groups studied. Males (N = 667) had an energy intake of 2000 kcal/day during childhood that increased to over 3000 kcal/day in adolescence. Energy sources for both sexes were approximately 15% protein, 38% total fat, 15% saturated fat, 6% polyunsaturated fat, 48% total carbohydrate, 19% starch, and 11% sucrose; cholesterol intake averaged about 145 mg/1000 kcal. For both sexes, fat intake increased with age. Compared to females, males ingested greater amounts of cholesterol and total and saturated fat.

Adolescent↗
PubMed1983

The effect of chronic anticonvulsant therapy on serum lipids and lipoproteins in epileptic children.

We measured serum lipids and lipoproteins in 33 epileptic children who were treated with phenobarbital, valproate, and carbamazepine. High-density lipoprotein cholesterol (HDL-c) was significantly higher in the epileptic children than in two control groups: healthy nonepileptic children, and epileptic children before starting anticonvulsant therapy. Our findings indicate that anticonvulsant drugs should be added to the list of substances that affect serum HDL-c.

Adolescent↗
PubMed1983

Strongyloidiasis in infancy. Case report and review.

A 15-month-old child with extreme failure to thrive due to intractable diarrhea since the age of 20 days was found to have live Strongyloides larvae in aspirated duodenal juice. Larvae were seen embedded in crypts of jejunal mucosa obtained by peroral biopsy. Following treatment with thiabendazole, a dramatic recovery ensued. The pathophysiology and clinical spectrum of strongyloidiasis is reviewed and the importance of its recognition stressed.

Biopsy↗
PubMed1982

Assessment of plasma total cholesterol as a test to detect elevated low density (beta) lipoprotein cholesterol levels (type IIa hyperlipoproteinemia) in young subjects from a population-based sample.

The measurement of plasma total cholesterol as a screening test for an increased plasma level of low density lipoprotein cholesterol (greater than age- and sex-adjusted 95th percentile) with a normal plasma triglyceride level (type IIa hyperlipoproteinemia) was assessed in 1325 young subjects, aged 6 to 19 years, from seven North American populations during the years 1972-1976. When the age- and sex-specific 95th percentile for total cholesterol was used as the cutpoint for hypercholesterolemia, almost one third of young subjects with type IIa hyperlipoproteinemia were undetected (false negatives), and 40% of the test results were falsely positive. Ninety-eight per cent of all non-type IIa subjects were correctly identified. Lowering the percentile cutpoint decreased the false negative results but increased the false positive results; increasing the cutpoint had an opposite effect. Females had higher percentile cholesterol values than males; when extrinsic, arbitrary cholesterol cutpoints (175-210 mg/100 ml) for screening were used, there were fewer false negative but more false positive results in the females than in the males. When the prevalence of type IIa hyperlipoproteinemia was increased from 5 to 50%, the false positive tests decreased from 40 to 2%. A two-step screening for hypercholesterolemia did not improve efficiency. The use of plasma total cholesterol as a test for type IIa hyperlipoproteinemia in a general population results in a relatively large number of false positive and false negative tests.

Adolescent↗
PubMed1981

Serum lipids and lipoprotein concentrations in young quadriplegic patients.

Serum lipids and lipoproteins were investigated in 10 young quadriplegic patients. All received intermittently a liquid formula diet via a naso-gastric tube, consisting of 2900 calories/day. The polyunsaturated/saturated fatty acids ratio was 1.1 : 1. Their mean body weight was 70% of the ideal body weight. The results were compared to a control group receiving a diet containing 2600 calories per day, and the polyunsaturated/saturated fatty acids ratio was 0.9 : 1. Their mean body weight was 95% of the ideal body weight. In the quadriplegic group the serum HDL-cholesterol levels and linoleic acid content of cholesterol ester were reduced. Similar findings have been observed in patients with coronary disease.

Adolescent↗
PubMed1980

Serum lipids and lipoprotein concentrations during the acute phase of myocardial infarction.

The concentrations of serum lipids and lipoprotein cholesterol were measured serially during the acute phase (14 days) following myocardial infarction (MI) in 13 male survivors. All patients were re-examined at least two months after discharge from hospital. A significant increase in serum triglyceride (TG) concentration occurred during the acute phase, with values returning to baseline two months after recovery. No changes in the concentrations of the other lipids or lipoprotein cholesterol were observed.

Acute Disease↗
PubMed1980

Cannabidiol and phenytoin: a structural comparison.

Conformational energy maps have been computed for the antiepileptic agents phenytoin and cannabidiol by the quantum-mechanical method of perturbative configuration interaction with localized orbitals (PCILO). The computation indicates that the spatial relationship between the two rings in the two drugs is similar and close to the respective structures in the crystal. This is supported by 1H and 13C NMR measurements. Hence, both compounds fulfill the stereochemical requirements suggested for anticonvulsant drug action.

Cannabidiol↗
PubMed1980

Plasma cholesterol and triglyceride distributions in 13,665 children and adolescents: the Prevalence Study of the Lipid Research Clinics Program.

The age-, race-, sex-specific distributions for plasma cholesterol (CH) and triglyceride (TG) are described for the 13,655 individuals under 20 years of age who were examined at the first visit (visit I) of the Prevalence Study of the Lipid Research Clinics (LRC) Program. Composite findings are presented from the seven North American LRC's where children were included in the target population. Cholesterol values are higher for blacks than for whites, but triglyceride values are higher for whites than for blacks. In both the CH and TG distributions for the combined races, the mean values for females are generally higher than for males. For cholesterol, consistent age-associated differences occur. On average, the CH values peak in late childhood and decline during adolescence. The decrease in mean values for CH is most marked for white males. The values for TG tend to increase in early adolescence. This report expands the available information about lipid distributions in young populations and describes the extent of the variation in plasma lipids associated with race and sex for each year of age, 0 to 19 years.

Adolescent↗
PubMed1980

Plasma high-density lipoprotein cholesterol in children and young adults. The Lipid Research Clinics Program Prevalence Study.

We examined the decline in high-density lipoprotein cholesterol in adolescent males and the postadolescent sex differences in HDL cholesterol levels. Prevalence data are presented for 1639 white males and females ages 6-25 years from six populations of the Lipid Research Clinics Program. The association of HDL cholesterol with age, smoking habits, and anthropometric, clinical chemistry and nutritional variables was examined by correlation and regression analyses. Although mean HDL cholesterol levels in children ages 6-10 years were lower in females than in males, HDL cholesterol levels gradually increased with age in females, while in males the mean HDL cholesterol levels declined form 55.9 mg/dl at ages 6-10 years to 45.5 mg/dl at ages 18-25 years. In young adults, HDL cholesterol levels were an average of 10.5 mg/dl higher in females than in males. In the 6-10-year-old age group, none of the study variables was significantly associated with HDL cholesterol. In the 11-17-year-old subjects, significant associations were noted with several variables, especially in the males. The strongest association was an inverse association with weight in males. In the young adults ages 18-25 years, significant inverse associations were found with weight and alkaline phosphatase in both sexes and with sucrose and smoking in females. The data suggested that the most important influence on HDL cholesterol levels in adolescent males are changes in gonadal hormone levels and that some of the factors known to influence HDL cholesterol levels in older adults are already associated with HDL cholesterol in adolescents and young adults.

Adolescent↗