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Biomedical subjects

M H Witte

Publications and source records attributed to M H Witte.

At least 109 records · Page 6Linked to original sources
PubMed1982

Attitudes toward women physicians in medical academia.

To determine attitudes toward women physicians within medical academia, we administered a survey to a probability sample of male and female senior medical students, faculty, and top-level administrators in a randomized, stratified subset of ten medical schools. Of the 984 respondents (65% response rate), men were much less supportive overall than women of female leaders. While women strongly disagreed with the idea that women physicians who spend long hours at work neglect home and family, men were almost equally divided on this issue. Each group rated the "typical" faculty member as "strong, fair, and progressive," but male faculty also were characterized as "egotistical" while female faculty were rated more "sensitive and altruistic." Male students were least likely to support a search for a female dean, hiring more female faculty members, or accepting an incoming class in which the majority were women.

Administrative Personnel↗
PubMed1982

Synergism between the spleen and serum complement in experimental pneumococcemia.

To examine the interplay between the spleen and complement activation in host defense against pneumococcemia, serial colony counts in blood and survival rates were studied after high-dose (10(5)) and low-dose (10(2)) intravenous challenge with growth-phase Streptococcus pneumoniae type 3 in rats with splenic remnants of varying size (partial, total, or no splenic resection) and with or without complement depletion (by pretreatment with cobra venom factor [CVF]). After high-dose challenge, the combination of total splenectomy and CVF produced greater pneumococcemia and higher mortality than either factor alone. After low-dose challenge, survival was uniform except when CVF was coupled with total splenectomy or splenic remnants less than one third of normal size, combinations which resulted in extremely high early mortality. This synergistic interaction between total splenectomy and CVF reveals a serious postsplenectomy immune defect and provides a highly sensitive assay of residual protective function in the spleen.

Animals↗
PubMed1981

Thoracic duct cannulation via a transjugular vascular endoscope (lymphoscope) in the dog.

We describe the feasibility of transjugular endovascular visualization and cannulation of the canine cervical thoracic duct using a flexible cholangioscope modified for lymphoscopy. The lymphoscope is composed of a prismatic side-view optic with a catheter guide channel attached by a metal cap to the terminal end. The technique has clinical applicability to the study of neoplastic diseases, examination and depletion of lymphocyte subpopulations in immunologic disorders, and perhaps the overcoming of increased resistance to lymph flow at the cervical lympho-venous junction in edematous conditions characterized by excessive lymph formation.

Animals↗
PubMed1980

Circulatory control of splenic hyperfunction in children with peripheral blood dyscrasia.

Ligation of the splenic artery was performed upon six children with a variety of peripheral cytopenias associated with hypersplenism to decrease splenic hyperfunction while preserving some splenic tissue. While this procedure initially improved the peripheral blood values in five patients--two patients with hereditary spherocytosis, one patient with idiopathic thrombocytopenic purpura, one patient with pyruvate-kinase hemolytic anemia and one patient with posthepatitic cirrhosis and splenomegaly--the hematologic derangement gradually recurred in four, necessitating eventual splenectomy in two. The sixth patient, an infant with histiocytosis-x, died soon after ligation of the splenic artery. Scintiscans of the spleen corroborated regrowth of the splenic remnant, principally the lower pole to which the vascular supply in the splenocolic ligament was not interrupted. Although ligation of the splenic artery is safe and promptly reduces splenic overreactivity, this operation can only be viewed as temporizing and not as definitive treatment of hypersplenism. On the other hand, in view of the protective function of the spleen against certain bacteria and protozoa, particularly in children with blood dyscrasia, the idea of achieving eusplenism or mild hyposplenism rather than asplenism by a graded reduction in the functional splenic mass through ischemic treatment of hypersplenism seems sound. Alternative methods of circulatory control, for instance, embolization of the splenic artery, of splenic function should be cautiously pursued.

Blood Cell Count↗
PubMed1980

Lymph imbalance in the genesis and perpetuation of the ascites syndrome in hepatic cirrhosis.

Despite extensive study, the pathogenesis of cirrhotic ascites and its relationship to salt and water retention and the hepatorenal syndrome remain unclear. This article reexamines the underlying disturbance in microcirculatory exchange of fluid and protein in the liver and digestive tract and specifically stresses that, in keeping with current interpretation of the Starling hypothesis, ascites appears when the driving force of elevated portal pressure overwhelms the "safety factors" of widened transmural colloid asmotic pressure gradient and accelerated regional lymph flow. In light of recent findings that enhancement of ascitic fluid returned to the bloodstream produces a natriuresis, diuresis, and amelioration of ascites, a "lymph imbalance" theory distinct from the "classic" and "overflow" theories is advanced. This theory proposes that a circulatory imbalance between the rate of fluid leaving and returning to the bloodstream (i.e., the relative rates of lymph formation and lymph absorption) is responsible for a maldistribution of extracellular fluid, which, in turn, stimulates renal salt and water retention, progression of ascites, and finally, the hepatorenal syndrome. Should compensatory factors suffice to prevent or reverse this lymph imbalance, the full cycle is not activated or, if already operating, is deactivated. Thus, portacaval shunt (by reducing the rate of lymph formation) or peritoneovenous shunt (by acting as a megalymphatic collateral to accelerate resorption as well as prevent sequestration of peritoneal fluid), both tend to restore the lymph balance and thereby suppress salt and water retention, correct functional oliguria, and ameliorate ascites.

Acute Kidney Injury↗
PubMed1979

Women physicians in medical academia. A national statistical survey.

We determined the representation of women physicians on US medical school faculties by enumeration from school catalogues according to professorial rank, title series, and department affilitation. We also compiled similar data for top-level administrative posts, using periodic chronological comparisons from 1955 through 1977 and 1978. Despite a burgeoning population of women medical students, we found a pattern of underuse of women physicians characterized by limited upward mobility on the faculty (professor: median, 3.0%; range, 0% to 18.2%; assistant professor; median, 7.3%; range, 0% to 28.7%). There were no women in chief executive positions.

Administrative Personnel↗
PubMed1979

Oxygen exchange in the mesenteric microcirculation of the dog.

The relationships of O2 tension in mesenteric lymph (PmlO2) and mesenteric venous blood (PmvO2) to intestinal O2 delivery/O2 consumption (DO2/VO2) were examined after graded hemorrhage (10 dogs), stepwise increments in FIO2 (4 dogs), and regional infusion of papaverine (2 mg/min or IV glucagon (25 microgram/kg) (4 dogs). Measurements included superior mesenteric arterial flow (SMA-Q), PaO2, PmlO2, and arterial and mesenteric venous blood O2 content (CaO2, CmvO2). Intestinal DO2 was calculated as the product of SMA-Q and CaO2, and VO2 was calculated from the Fick equation [SMA-Q X (CaO2 - CmvO2)]. Graded hemorrhage lowered SMA-Q, DO2 and DO2/VO2 and increased splanchnic O2 extraction (CaO2 - CmvO2). Elevation of FIO2 increased PaO2, PmvO2, and PmlO2. Both PmlO2 and PmvO2 varied directly with DO2/VO2 and PaO2, but PmlO2 showed greater sensitivity to PaO2. Papaverine and glucagon both increased SMA-Q, DO2, CmvO2, and PmvO2, BUT PmlO2 rose after papaverine, indicating greater capillary perfusion, and fell after glucagon, suggesting diversion of mesenteric blood flow through arteriovenous shunts. Thus, either PmvO2 or PmlO2 is ordinarily an accurate measure of intestinal tissue oxygenation, but the disparate response after glucagon suggests that PmlO2 is a more reliable indicator.

Animals↗
PubMed1979

Weight gain and edema on methadone maintenance therapy.

Methadone HCl is currently legally dispensed to approximately 80,000 heroin addicts in the United States. It is widely heralded as being virtually free from other than narcotic side effects. This report describes in detail three patients with massive fluid gain in a population of 420 addicts treated at the Hope Center methadone program in Tucson, Arizona. In no patient was there a prior history of edema, and an intensive search failed to reveal a cause for the swelling. Weight gain uniformly began 3 to 6 months after initiation of methadone or a sharp increase in the dosage, and in all three patients during periods when they sharply reduced or discontinued methadone, edema was resolved associated with a concomitant loss of weight.

Adult↗