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Biomedical subjects

B Newman

Publications and source records attributed to B Newman.

At least 217 records · Page 12Linked to original sources
PubMed1987

Environmental and behavioral determinants of fasting plasma glucose in women. A matched co-twin analysis.

Comparing results of an unmatched analysis in a sample of unrelated persons created by randomly selecting one twin from each pair with results of a matched monozygotic co-twin analysis provides a means of distinguishing environmental influences from genetic influences on a dependent variable of interest. Determinants of the fasting plasma glucose level were investigated in a large sample of adult female nondiabetic twins from the Kaiser Permanente Twin Registry. In the subsample of unrelated persons, fasting plasma glucose was significantly and positively associated with age, body mass index, uric acid level, and alcohol intake and was significantly inversely related to leisure time physical activity. When monozygotic twins were treated as matched pairs, only the effects of body mass index and alcohol consumption remained significant, whereas the association with leisure time physical activity was greatly reduced and no longer statistically significant. These results suggest that behavioral and therefore alterable aspects of obesity and alcohol consumption influence the fasting plasma glucose level; alcohol consumption may be a risk factor for non-insulin-dependent diabetes mellitus; and common underlying genetic factor(s) may be responsible for the negative association between physical activity and fasting plasma glucose.

Adult↗
PubMed1987

Contrast media and renal function in the immature kidney.

In the immature rabbit, a real-time method for monitoring filtration fraction (FF) to demonstrate acute changes in the kidney's response to intravenous injections of contrast media was used. The renal arteriovenous difference of an agent cleared by the kidney as a pure glomerular filtrate was measured with a gamma detector, and FF was calculated by a computer and displayed on a TV monitor. The effect of FF, arterial pressure (BP), and renal blood flow (RBF) of Renografin-60 and an agent with a much lower osmolality, Iopamidol 300, was examined in anesthetized four-to five-week-old rabbits. Renografin (2 and 4 mL/kg, IV) induced dose-related decreases in FF of 40% and 73%, decreased arterial pressure by 12% and 30%, and at the 4 mL/kg dose increased RBF by 77%. Iopamidol (4 mL/kg) induced a smaller, 41% decrease in FF than the same dose of Renografin (P less than .01), a smaller, 28% increase in RBF (P less than .001), and, unlike Renografin, induced a small increase in BP. Comparison of the magnitude of the reduction of FF induced by a 2-mL/kg IV dose of Renografin in the present immature rabbits with previous results in mature rabbits shows a surprising similarity (P = .33), despite lower resting BP, RBF, and glomerular filtration rate, as well as reduced tubular function in the immature animals.

Animals↗
PubMed1987

Unusual renal mass in a newborn infant.

A newborn male infant had a right flank mass and hematuria. A solid renal mass was demonstrated on ultrasound and computed tomography studies, while Doppler studies suggested the diagnosis of renal vascular injury. Laparotomy disclosed avulsion of the right renal pedicle, and a right nephrectomy was performed. Traumatic renal hemorrhage should be considered in the differential diagnosis of a solid renal mass in the neonate, especially if the history or physical findings suggest trauma or if there is evidence of abdominal hemorrhage.

Birth Injuries↗
PubMed1987

Bowel perforation in Hirschsprung's disease.

A review of the medical records of 45 infants less than 1 year old with Hirschsprung's disease identified two (4.4%) who presented with bowel perforation. A literature survey was done to evaluate the relationship between bowel perforation of the bowel early in the course of Hirschsprung's disease indicates that: the infant under 4 months old is at the greatest risk; the majority of cases (62%) were associated with long-segment or total colonic Hirschsprung's disease; the most common sites of perforation were the proximal colon (68%) and appendix (17%); in cases with a short or intermediate length of aganglionic bowel, the perforation was proximal to or at the site of transition, but in 84% of infants with total colonic aganglionosis the perforation was situated in aganglionic bowel. Hirschsprung's disease should be a prime differential consideration in a young infant with penumoperitoneum caused by distal bowel perforation.

Enterocolitis↗
PubMed1986

The effect of isoflurane-induced hypotension on cerebral blood flow and cerebral metabolic rate for oxygen in humans.

Deliberate hypotension was induced with isoflurane (mean inspired concentration 2.3 +/- 1.0%) in 12 patients undergoing craniotomy for clipping of cerebral aneurysms. Global cerebral blood flow (CBF) was measured before, during, and after hypotension. Arterio-venous O2 content difference was measured concomitantly, and the cerebral metabolic rate for oxygen (CMRO2) was calculated from these data. Mean arterial pressure (MAP) was reduced from 78 +/- 5 mmHg to 51 +/- 7 mmHg and then returned to 82 +/- 8 mmHg. Mean CBF before hypotension was 49 +/- 14 ml X 100 g-1 X min-1 and was unchanged during (45 +/- 12 ml X 100 g-1 X min-1) and after (49 +/- 15 ml X 100 g-1 X min-1) hypotension. The CMRO2 before hypotension was 2.0 +/- 0.6 ml X 100 g-1 X min-1. This was statistically significantly (P less than 0.025) reduced to 1.5 +/- 0.5 ml X 100 g-1 X min-1 during hypotension and then returned to 2.2 +/- 0.6 ml X 100 g-1 X min-1 on return to normotension. This indicates that the global cerebral O2 supply-demand balance was favorably influenced by isoflurane. No complications could be attributed to the hypotensive technique. We conclude that, with regard to global cerebral oxygenation, isoflurane is a safe agent with which to induce hypotension during neurosurgery.

Adult↗
PubMed1985

C57BL/6 x BALB/c hybridomas produce IgA which assembles into molecules with covalent bonds between heavy chains (H) and light chains (L), and into molecules lacking covalent bonds between H and L.

Examination of the gel electrophoresis patterns of 14C-biosynthetically labeled immunoglobulin from C57BL/6 X BALB/c IgA hybridomas reveals that each of the monoclonal cell populations produces two different forms of IgA: molecules with heavy chains (H) and light chains (L) joined by disulfide bonds, as well as molecules with H and L being noncovalently associated. The possible origin of this was explored: Southern blot analysis of the hybridoma DNA indicated that only one alpha gene is expressed by each cell line; hybridoma cells labeled in the presence of the N-glycosylation inhibitor tunicamycin exhibit both forms; and electrophoresis of biosynthetically labeled spleen cell IgA from C57BL/6, BALB/c and (C57BL/6 X BALB/c) F1 mice shows that BALB/c mice produce only the noncovalently associated form, while C57BL/6 and (C57BL/6 X BALB/c) F1 mice produce both. Possible mechanisms by which two types of IgA may be assembled by the same hybridoma cell are discussed.

Animals↗
PubMed1984

Self-adhesive preapplied electrode pads for defibrillation and cardioversion.

The efficacy of self-adhesive electrode pads for defibrillation and cardioversion was assessed in 80 patients who received 267 shocks from self-adhesive pads. In all but two patients, defibrillation or cardioversion was achieved at least once. The pads were equally effective when used in the apex-anterior or apex-posterior position. The transthoracic impedance using self-adhesive pads was 75 +/- 21 ohms (mean +/- standard deviation), which is similar to previously reported transthoracic impedance in defibrillation, using standard hand-held electrode paddles of 67 +/- 36 ohms. It is concluded that self-adhesive electrode pads are effective for defibrillation and cardioversion.

Arrhythmias, Cardiac↗
PubMed1984

Coughs cause systemic blood flow.

Although it is known that rhythmic coughing can preserve consciousness during ventricular fibrillation, the arterial pressure transients which result have not yet been shown to reflect forward blood flow in man. The effectiveness of cough in causing forward flow in eight normal volunteers with bradycardia was studied. They coughed between cardiac cycles, using an audio and visual display of the electrocardiogram. The force of the cough was varied and measured with an oesophageal balloon. Blood flow was recorded with a Döppler velocity probe over the radial artery and a finger or ear photoplethysmograph. Motion artefact on the Döppler record due to coughing was excluded by transiently obstructing the brachial artery. We compared the areas under 5-10 consecutive Döppler and photoplethysmograph pulse flow tracings due to the cough and heart beat with those due to the immediately preceding heart beat alone. They were significantly increased. This augmentation was greater in those flow pulses accompanied by a more vigorous cough. It is concluded that coughing is associated with an effort dependent forward flow pulse in the arterial circulation.

Adult↗
PubMed1983

Combining site specificities of mouse hybridoma antibodies to dextran B1355S.

The combining sites of 12 mouse hybridoma antibodies to dextran B1355S have been characterized by quantitative precipitin assay. All antibodies preferentially bind the immunizing antigen B1355S and two other class I dextrans, B1498S and B1501S, but show substantial differences in the extents to which they cross react with class I dextrans, suggesting their clustering into five groups. Three myeloma proteins, CAL20 TEPC1035, J558, and MOPC104E, which bind dextran B1355S, each fall into a different group. There appears to be a substantial, but imperfect, correlation of DH region structure and individual idiotypic determinants with dextran binding patterns. Proteins with RY DH segments and IdI (J558) idiotypes are in groups 1 or 3, and proteins with YD DH segments and IdI (MOPC104E) idiotypes are exclusively in group 5. However, identical patterns of precipitin curves accompany very different sequences in CDR3. Antibodies of group 1, which react only with class II dextrans, differ the most in primary sequence, a finding suggesting that subsites responsible for cross reactivity with class I dextrans may be blocked and that this may be effected by side chains of different amino acids. This finding delineates a new aspect of the relationship of variability in amino acid sequence to antibody complementarity.

Amino Acid Sequence↗
PubMed1983

Cardiac output and the recumbent position in late pregnancy.

Changes in cardiac output were measured by transcutaneous aortovelography in 30 pregnant patients and in 30 control subjects with change of position from the supine. When compared to the supine position, the left and right lateral and left 15 degrees tilt positions caused statistically significant increases in cardiac output, whereas the right 15 degrees tilt position did not. Neither fetal head engagement nor the time spent in each position had significant effects on the changes in cardiac output. It was not possible to identify a subgroup of pregnant patients who were particularly sensitive to changes in posture.

Adolescent↗