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Biomedical subjects

R Schwartz

Publications and source records attributed to R Schwartz.

At least 361 records · Page 20Linked to original sources
PubMed1979

The role of hepatic control of glucose homeostasis in the etiology of neonatal hypo- and hyperglycemia.

Precise control of glucose homeostasis is well recognized in the adult. Going from a period of complete dependence on the maternal organism for delivery of substrate, the fetus is born not only with a need to furnish himself with glucose for energy and rapid growth but also with the need to maintain a balance between glucose deficiency and excess. This is especially difficult because of the intermittent nature of exogenous oral intake in the neonatal period. Development of glucose homeostasis requires a balance between substrate availability (both absolute and relative) and coordination of hormonal, neural and enzymatic systems. The large number of conditions producing or associated with both hypo- and hyperglycemia in the newborn, especially the low birth weight or sick neonate, emphasizes this vulnerability. Newer techniques including stable isotope methodology, now being employed with increasing frequency, will help define maturation of neonatal carbohydrate homeostasis and further clarify nutritional requirements in this transitional period.

Adult↗
PubMed1979

Verbal and nonverbal memory abilities of adult brain-damaged patients.

Retention abilities of three groups of patients were investigated in this study; ten left hemisphere brain-damaged patients (aphasics), ten right hemisphere-damaged patients, and ten patients with no known neurological deficits who served as controls. The patients were asked to detect repetitions of a word within a list of words presented either auditorily or visually. They were also tested for their ability to detect repeated pictures and repeated shapes. It was discovered that the aphasics had greater difficulty than the other two groups in retaining stimuli on the verbal subtests presented auditorily or visually. On the other hand, the right-hemisphere-damaged patients performed poorly on the visual subtests (verbal and nonverbal), but performed well on the auditorily presented verbal test. Application of these findings is offered for the clinical treatment of both right and left brain-injured patients.

Aged↗
PubMed1979

Intestinal calcium absorption and bone morphology in magnesium deficient chicks.

Calcium absorption was measured by 47Ca disappearance from ligated duodenal loops and 47Ca uptake by tibiae in chicks fed diets containing one of four levels of Mg for two weeks. The diets, otherwise identical, contained 88 (group 1), 150 (group 2), 200 (group 3) and 1000 (group 4) ppm Mg. There were no statistically significant differences in 47Ca absorption. Mucosal CaBP and intestinal alkaline phosphatase were slightly, but not significantly, elevated in the Mg depleted chicks in groups 1 and 2 compared to groups 3 and 4. Microscopic examination of the tibiae showed marked alterations in morphology in chicks fed the 88 ppm Mg diet. The thickness of the epiphyseal plate was reduced, and the morphologic signs of osteolysis and chondrolysis, normally observed in the metaphysis, appeared to be absent. The mid-diaphysis was thickened and showed marked reduction in both osteoblast and osteocytie activity. Blood calcium levels were significantly reduced in the Mg deficient chicks. It was concluded that Mg depletion in chicks altered Ca homeostasis primarily by changing bone structure and function.

Alkaline Phosphatase↗
PubMed1979

Cefaclor in the treatment of susceptible infections in infants and children.

Cefaclor is a new oral cephalosporin with in vitro activity against a wide variety of organisms including S. aureus, S. pneumoniae, S. pyogenes and H. influenzae (including ampicillin-resistant strains). Seventy-nine patients ranging in age from 2 months to 14 years with soft tissue infections (17 cases), otitis media (17), and streptococcal pharyngitis (45) were studied. They received cefaclor orally at a dose of 40 mg/kg per day in three or four divided doses for a minimum of five days. Results were generally good with favourable clinical and bacteriological responses obtained in 90% of cases. Most patients became afebrile within 48 hours after starting cefaclor. Two patients with H. influenzae cellulitis and bacteraemia defervesced within 24 hours and their blood cultures became negative promptly. Hepatic, renal and haematopoietic studies showed no adverse reactions except for an occasional increase in the eosinophil count with no clinical counterpart of hypersensitivity. Pharmacokinetic studies revealed that following a 10 mg/kg oral dose, peak serum levels of 8 micrograms/ml were observed at one hour, followed by a rather rapid tapering off so that at the end of four hours, virtually no cefaclor was detectable in serum.

Adolescent↗
PubMed1978

Effects of chronic hyperinsulinaemia on hepatic enzymes involved in lipogenesis and carbohydrate metabolism in the young rat.

Chronic (6 days) hyperinsulinaemia in young rats produced lower blood glucose concentrations and augmented body- and liver-weight gain. The insulin-treated rats had increased hepatic activities of citrate-cleavage enzyme, 'malic' enzyme and high-substrate (6.6 mM-phosphoenolpyruvate) pyruvate kinase, and decreased glucose 6-phosphatase. There were no changes in activities of phosphoenolpyruvate carboxykinase, phosphofructokinase, low-substrate (1.3 mM-phosphoenolpyruvate) pyruvate kinase, glucokinase and hexokinase.

Animals↗
PubMed1978

The increasing incidence of Ampicillin-resistant Haemophilus influenzae. A cause of otitis media.

Middle ear exudate was obtained by myringotomy or aspiration from 625 suburban children, aged 1 month to 12 years, who had acute otitis media; bacterial pathogens were isolated from 71%. Haemophilus species were isolated from 212 (29%), and Streptococcus pneumoniae from 205 (28%). From 1975 to August 1977, the number of Haemophilus isolates found to be resistant to ampicillin has appreciably increased. Currently, 8% of all cases of acute otitis media in the Washington, DC, area are due to H influenzae resistant to ampicillin. Thirty-one of 35 patients with resistant H influenzae otitis were treated with an erythromycin/sulfisoxazole combination with an impressive clinical response. Twenty-six of these 31 cases had failed to have H influenzae eradicated by an average of ten days of oral ampicillin in recommended doses.

Acute Disease↗
PubMed1978

Glycohemoglobin (HbAIc): a predictor of birth weight in infants of diabetic mothers.

Hemoglobins AIa-c (fast Hb), minor variants of HbA, are elevated in patients with diabetes mellitus. Recent studies indicate a relationship of fast hemoglobins, especially HbAIc (glycosylated form), to chronic hyperglycemia. Since infant oversize has been attributed to maternal hyperglycemia and fetal hyperinsulinemia, the hemoglobin HbAIc fraction was compared to birth weight (actual and relative to gestational age) and to maternal glucose tolerance. Normal (13), probably normal (8), gestational diabetic (10), and insulin-dependent women (14) were studied in the third trimester; women with advanced diabetic vascular disease were excluded. When corrected for gestational age, relative birth weights correlated in a significant linear regression with HbAIc (n = 45, r = 0.57, P less than 0.001). Third trimester maternal glucose tolerance (Kt) of women, not insulin dependent, correlated in a signigicant manner with both HbAIc (P less than 0.05) and birth weight for gestational age (P less than 0.01).

Birth Weight↗
PubMed1978

Infection of cultivated mouse peritoneal macrophages with lymphocytic choriomeningitis virus.

Lymphocytic choriomeningitis virus strain WE multiplied in cultivated peritoneal macrophages from unstimulated NMRI mice. As revealed by immunofluorescence technique, most cells participated in the infectious process. They were not, however, functionally altered. Morphologically, infected cells contained more cytoplasmic vacuoles, but these were also present, though less numerous, in uninfected ageing cells and in cells having phagocytosed Latex beads. As compared with the WE strain virus, the E-350 (Armstrong) strain multiplied more slowly to lower titres, but the proportion of infected cells was similar.

Animals↗
PubMed1978

Haemoglobin Aic (glycohaemoglobin) in diabetic pregnancy: an indicator of glucose control and fetal size.

Haemoglobin AIc (Hb AIc), a glycohaemoglobin present in normal human blood, is elevated in glucose intolerant individuals. In non-pregnant diabetic subjects, a direct relationship has been established between per cent Hb AIc and blood and urinary glucose levels over weeks and months. In this study, Hb AIc level and mean random blood glucose concentration in the third trimester of pregnancy were found to correlate directly in 12 diabetic women without vascular disease (P less than 0.001). In this same group of women, third trimester Hb AIc levels also correlated significantly with infant birth weight (P less than 0.05) and birth weight adjusted for gestational are (P less than 0.01). Finally, third trimester mean blood glucose concentrations also correlated directly with birth weight (P less than 0.05) and adjusted birth weight (P less than 0.001). In pregnancies complicated by diabetes, rigid glucose control has been recommended to achieve optimal fetal and maternal outcomes. Hb AIc is a new tool with which to assess blood glucose control during diabetic pregnancy.

Birth Weight↗
PubMed1978

Sequential intravenous glucose tolerance: responses of newborn and adult.

Acute sequential intravenous glucose tolerance tests were performed at an interval of 120 min in 12 normal fasting adults, 5 normal infants, and 6 infants of gestationally diabetic mothers. Glucose disposal (Kt) and plasma insulin elevations were remarkably similar in the paired adult studies. In contrast, the studies in all infants were highly variable although they had similar initial plasma insulin levels (less than 10 micronU/ml). The rates of glucose disposal in the infants (1.43 and 1.47%/min) were slightly slower than the adult rates (1.66%/min). The plasma insulin responses, in contrast, were higher and more sustained throughout the second half of the test in the infants as a group. There was remarkable heterogeneity in the responses of the infants which obscured any differences between the groups.

Adult↗
PubMed1978

Potentiation of lymphocyte activation by colchicine.

Proliferation of human lymphocytes induced by IO4- is potentiated by 30 min exposure to colchicine (10(-6)M), whereas the response to Con A is inhibited. Treatment with colchicine before or after IO4- modification has similar enhancing effects. Lumicolchicine does not alter proliferative responses. In addition to the proliferation of IO4--oxidized cells, irradiated IO4- modified lymphocytes induce proliferation when mixed with untreated lymphocytes. Enhancement occurs in both these conditions only when IO4--modified cells are treated with colchicine. Preliminary data indicate that proliferation in mixed lymphocyte cultures is also potentiated when either stimulating or responding cells are pretreated with colchicine. These findings suggest a selective stimulatory effect of colchicine on lymphocyte responses induced by cell-cell contact. Agents that modify microtubular assemblies might regulate the induction of immune responses that involve cellular interactions.

Adult↗