Search PubMed⌕ Search

Biomedical subjects

R Schwartz

Publications and source records attributed to R Schwartz.

At least 379 records · Page 21Linked to original sources
PubMed1978

In vivo formation of dopamine from 3,4-methylenedioxyphenethylamine in the rat.

Administered 1-C14-3,4-methylenedioxyphenethylamine led to the excretion of about 2% of the urinary C14 as conjugated dopamine and 3-methoxytyramine metabolites, in tranylcypromine treated rats. The amine was not excreted unchanged. The major metabolites were identified as conjugates of methylenedioxyphenylacetic acid, homovanilic acid and dihydroxyphenylacetic acid. The latter are derived by the further metabolism of conjugated methylenedioxyphenylacetic acid. Administered tranylcypromine doubled the excretion of conjugates of labeled dopamine and3-methoxytyramine. NADPH served as a cofactor for the microsomal demethylenation of the amine.

3,4-Methylenedioxyamphetamine↗
PubMed1978

Evaluation and characteristics of currently available inulin.

Inulin was not available for clinical testing in the United States between February 1973 and July 1975 because the raw material received in the United States differed from previously manufactured lots in molecular weight, glucose content, optical rotation, melting point, and water solubility. The comparability of the "new" and "old" inulin preparations was assessed in 12 adult male spinal cord injury patients, seven with normal renal function and five with compromised function. The "new" inulin proved to be as accurate and safe an agent for the determination of glomerular filtration rate as the previously available material in both groups of patients, and was made available for general clinical use in the United States in July 1975.

Adult↗
PubMed1977

Acute purulent otitis media in children older than 5 years. Incidence of Haemophilus as a causative organism.

It is generally believed that Haemophilus influenzae is not commonly a causative agent of otitis media in children older than 5 years of age. We recently studied cases of 58 children, aged from 5 to 9 years, who had acute otitis media. Haemophilus species were the causative agents in 36% of cases. This high incidence of Haemophilus isolation from the middle ear exudate of these children has important therapeutic implications; antibiotics effective against H influenzae should be employed when dealing with otitis media in this older age group.

Acute Disease↗
PubMed1977

Lack of gastrointestinal enhancement of the insulin response to glucose in newborn infants.

Forty-five normal newborn infants were infused with glucose at constant rates by intravenous or nasogastric routes. Blood glucose rose to higher levels during IV than during NG infusions at identical rates; however, the glycemic responses were similar when NG glucose infusions at 12 mg/minute/kg were compared with IV infusions at 6 mg/minute/kg. The plasma insulin responses to glucose were not enhanced by NG administration. Thus, enterohormonal responses to glucose may not affect pancreatic beta cell regulation of glucose assimilation in the newborn period.

Administration, Oral↗
PubMed1977

Serum and duodenal alkaline phosphatase levels in fed and fasted magnesium deficient rats.

Rats depleted of magnesium for 13 days were killed after 18 to 20 hours of fasting or 2 hours after consumption of a standard-sized meal. Serum and duodenal alkaline phosphatase (AP) were reduced in fasted magnesium depleted rats compared to pair-fed and ad libitum-fed controls. With refeeding, serum alkaline phosphatase levels rose significantly in all groups, but the levels in refed Mg deficient rats remained below serum levels of fasted control rats. Inhibition of AP activity with L-phenylalanine and urea suggested that the differences in AP levels of fasted and fed rats were mainly due to enzymes of intestinal origin. Intestinal AP levels increased after feeding in all groups, but were proportionately greatest in Mg depleted rats. The pattern of serum and duodenal AP in fed and fasted rats and the results of polyacrylamide disc gel electrophoresis (PADGE) in duodenal AP extracts suggest that Mg depletion alters the release of AP into the blood that normally occurs in response to feeding.

Alkaline Phosphatase↗
PubMed1976

Relationship of mineral status and intake to periodontal disease.

A periodontal index (PI), based on visual and radiographic data, was used to evaluate the severity of periodontal disease in a group of 80 dental patients. The average PI was 3.1 +/- 1.8 SD (0=no detectable lesions; 8=most severe lesions). The PI was directly related to patient age (r=0.73; P is less than 0.01). The serum concentration of calcium copper, iron, magnesium, manganese, and zinc was measured. Regression of PI on the serum constituents demonstrated that serum copper was linearly related (r-0.64; P is less than 0.001) to the PI. The other serum parameters were not correlated to the PI. Dietary protein, calcium, and vitamin A were slightly related to the PI, based on a 24-hr dietary recall. Dietary trace elements were not related to the PI. These results indicate that the serum copper concentration, in some way is related to the severity of periodontal disease. Possibly the observation is linked to the role of copper in the inflammatory response since inflammation is a characteristic of periodontal disease.

Calcium↗
PubMed1976

Effect of hypoxia on erythroblasts from avian fetal liver: adenosine triphosphate levels and hemoglobin synthesis.

A system for the isolation and functional evaluation of fetal liver erythroblasts is described. Isolated erythroblasts were prepared from 14-day embryonic avian livers and incubated at various oxygen tension (0, 5, 12, and 95%). The concentration of ATP in erythroblasts remained constant for at least 4 hr at 37degree, but was rapidly reduced by incubation in nitrogen. Protein synthesis as measured by L-[14C]leucine incorporation into cell protein occurred at a linear rate in 5%, 12%, and 95% oxygen, whereas little protein synthesis occurred at 0% oxygen. The effect of hypoxia on the type of hemoglobin synthesized was studied in this system by isolating the hemoglobin A, hemoglobin D, and hemoglobin H fractions and determining the incorporation of L-[14C]leucine. The major fraction, hemoglobin A, contained most of the radioactivity; smaller amounts were present in hemoglobin D and hemoglobin H, respectively. The relative proportion of each hemoglobin synthesized was not altered by oxygen from 5% to 95%. These results argue against a direct effect of oxygen on the type of hemoglobin synthesized at this stage of development.

Adenosine Triphosphate↗
PubMed1976

Effects of pregnancy on hemoglobin AIc in normal, gestational diabetic, and diabetic women.

Hemoglobin AIc, a normal minor hemoglobin, has glucose linked by a Schiff base to the N-terminal end of the beta chain. The glucose interferes with the binding of 2,3 diphosphoglycerate, probably resulting in an increased affinity of that hemoglobin for oxygen. Hb AIc is increased to twice normal levels in juvenile-onset (insulin-dependent) diabetes. In the present studies, the Hb AIc, when expressed as per cent of total hemoglobin, was found to be elevated slightly in pregnany normal (m = 6.97 per cent), pregnant nondiabetic obese (m = 6.89 per cent), and gestationally diabetic subjects (m = 8.77 per cent) above that of normal females (m = 5.68 per cent). A remarkable difference was observed between the nonpregnant diabetics (m = 12.77 per cent) and the pregnant diabetics (m = 8.46 per cent). This decrease in the level of Hb AIc in diabetics who are pregnant more than 30 weeks may reflect either a better state of diabetic control and/or a compensatory mechanism to protect the fetus by facilitating oxygen exchange from mother to fetus.

Adult↗
PubMed1975

Development of ureteral stone basket.

A new ureteral stone basket is presented which has several advantages over any available: it can be autoclaved, is less than 4 French, and has six wires. Clinical evaluation is included.

Humans↗