Biomedical subjects
Publications and source records attributed to C B Loadholt.
This study reports that education effects but not skin color effects were associated with blood pressure and the incidence of hypertension in a cohort of Black females in Charleston, South Carolina, observed over the period 1960-1975. The authors suggest that skin color may be a secondary (non-causal) associate of blood pressure in Blacks.
Platelets obtained from some diabetic patients show enhanced in vitro platelet aggregation. This study sought to determine if platelet obtained from insulin-dependent diabetic subjects synthesize increased quantities of the labile aggregating substance, thromboxane A2 (TXA2), and if it may play a role in the enhanced platelet aggregation. Arachidonic acid (1 mM)-stimulated TXA2 synthesis, as determined via radioimmunoassay of its stable metabolite TXB2, was significantly greater (P less than 0.01, N = 12) in platelet-rich plasma obtained from diabetics compared with matched controls. Arachidonic acid-stimulated TXB2 synthesis in the diabetic platelet-rich plasma was positively correlated with the ambient fasting plasma glucose (r = 0.61, P less than 0.02, N = 15). Platelet aggregation induced by arachidonic acid (0.4-0.8 mM) was inhibited significantly less by 13-azaprostanoic acid (P less than 0.04, N = 14), a competitive antagonist of the actions of prostaglandin H2 or TXA2 on platelets, compared with matched controls. The results support the notion that platelets obtained from some insulin-dependent diabetic subjects manifest increased synthesis of TXA2, which may contribute to the enhanced platelet aggregation.
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Platelets obtained from some diabetic patients show enhanced in vitro platelet aggregation. These studies were designed to determine if platelets obtained from diabetic subjects manifest increased metabolism of arachidonic acid to labile aggregating substances, such as thromboxane A2 (TXA2), and if they play a role in the enhanced platelet aggregation. Arachidonic acid stimulated TXA2 synthesis, as determined via radioimmunoassay of its stable metabolite TXB2, was significantly greater (p less than 0.01, n = 12) in platelet-rich plasma obtained from diabetic compared to matched controls. Arachidonic acid stimulated TXB2 synthesis in the diabetic platelet-rich plasma was positively correlated with the ambient fasting plasma glucose (r = 0.61, p less than 0.02, n = 15). Platelet aggregation induced by arachidonic acid (0.4-0.8 mM) was inhibited significantly less by 13-azaprostanoic acid (p less than 0.04, n = 14), an antagonist of the actions of prostaglandin H2 or TXA2 on platelets, compared to matched controls. We conclude that platelets obtained from some diabetic subjects manifest increased metabolism of arachidonic acid to labile aggregating substances which may contribute to the enhanced platelet aggregation.
Platelets obtained from some diabetic patients show enhanced in vitro platelet aggregation. This study sought to determine whether platelets obtained from diabetic subjects synthesize increased quantities of the labile aggregating substance. TXA2, and whether it may play a role in the enhanced platelet aggregation. Arachidonic acid (1 mM)-stimulated TXA2 synthesis, as determined via radioimmunoassay of its stable metabolite TXB2, was significantly greater (p < 0.01, n = 12) in platelet-rich plasma obtained from diabetic patients than in matched controls. Arachidonic acid-stimulated TXB2 synthesis in the diabetic platelet-rich plasma was positively correlated with the ambient fasting plasma glucose (r = 0.61, p < 0.02, n = 15). Platelet aggregation induced by arachidonic acid (0.4 to 0.8 mM) was inhibited significantly less than in matched controls by imidazole, a thromboxane synthetase inhibitor (p < 0.01, n = 11), and 13-azaprostanoic acid, an antagonist of the actions of PGH2 or TXA2 on platelets (p < 0.04, n = 14). We conclude that platelets obtained from some diabetic subjects manifest increased synthesis of TXA2, which may contribute to the enhanced platelet aggregation.
We studied 60 children, 2 weeks to 10 years old, prospectively by randomly assigning them to a SciMed membrane oxygenator or Harvey bubble oxygenator. Variables of cardiopulmonary bypass (CPB) were closely controlled: prime, circuit configuration, flow rate, and blood gases. Blood variables measured at eight intervals before, during, and after operation were as follows: seven plasma proteins, free hemoglobin, formed elements, and clotting functions. Preoperatively and postoperatively, we evaluated brain function (psychological testing), renal function (creatinine clearance), and pulmonary function (compliance changes and postoperative shunt function). Postoperative blood loss, fever, and length of hospitalization were also evaluated. We compared 302 variables by computer program. No difference (p greater than 0.05) between the two groups was found in any variable related to CPB or organ function (pulmonary, renal, or cerebral) or in hematological variables except free hemoglobin. After 5 and 60 minutes of CPB and the next day, it was significantly lower (p less than 0.05) in the group with a membrane oxygenator. Safety, cost, and convenience, not physiology, should be the major factors in considering membrane versus bubble oxygenators for cardiac operations in children.
A total of 120 patients who were to be delivered by cesarean section and who were at high risk of postoperative infection received three doses of either cefamandole, cephalothin or placebo perioperatively. Maternal serum levels for both antibiotics were in the therapeutic range. Although both drugs reduced the incidence of febrile morbidity and endometritis, only cefamandole significantly reduced the fever index. Risk factors for postoperative infections were the presence of ruptured membranes, labor, and internal fetal monitoring. Cefamandole beneficially influenced all risk factors while cephalothin was able to reduce only the risk of ruptured membranes. When a new method for obtaining endometrial tissue was utilized, 50% of cultures were negative. There was no difference in the organisms isolated from patients with and without endometritis.
Serum samples were collected from 20 healthy White and 33 Black infants before and after immunisation with three doses of diphtheria-pertussis-tetanus vaccine and with one dose of Haemophilus influenzae type b polyribose phosphate vaccine and meningococcal group A and group C polysaccharide vaccines. Antibodies to these immunogens were measured and sera were allotyped for several Gm, A2m, and Km antigens. A highly significant association was found between the Km(1) allotype and the immune responses (difference between post-immunisation and pre-immunisation antibody levels) to H. influenzae and meningococcus C polysaccharides in the White children.
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Autoantibody determinations in 1284 healthy Caucasian subjects of various age groups were made by indirect immunofluorescence for anti-nuclear, anti-gastric, and anti-thyroglobulin antibodies. A sex-dependent relationship between age and prevalence of anti-gastric and anti-thyroglobulin antibodies was found. No association was found between age and anti-nuclear antibodies.
Renin activity and aldosterone were evaluated relative to potassium levels and lead intoxication in 33 patients with a history of "moonshine" ingestion. Patients were divided into three groups: I, lead intoxicated with hyperkalemia; II, lead intoxicated without hyperkalemia; and III, not lead intoxicated without hyperkalemia. Those in group I demonstrated suppressed plasma renin activity, baseline and after furosemide, and blunted aldosterone responsiveness to furosemide. Plasma renin activity was not different in groups II and III, whereas aldosterone responsiveness was less in group II than in III. Group I patients tended to be older, had lower creatinine clearances, and six of nine had mild hyperchloremic acidosis. Diabetes and cortisol insufficiency were not present. Chronic lead intoxication due to illicit alcohol ingestion is associated with hyporeninemic hypoaldosteronism and hyperkalemia which appear to develop as the lead nephropathy progresses with duration and/or aging.
Products secreted by Streptococcus intermedius were studied for their effects on the immune response. Three different preparations of crude extracellular products from S. intermedius (CEP-Si) were found to have powerful suppressor activity in vitro as shown by inhibition of human lymphocyte proliferation (uptake of [3H]thymidine) and protein synthesis in response to a wide variety of stimulants, including mitogens and antigens, and suppression of plaque formation by human cells in response to sheep erythrocytes. CEP-Si was noncytotoxic, because cells incubated with high concentrations of CEP-Si and subsequently washed were viable and recovered their ability to respond to mitogens, and because leukocyte migration was not inhibited by CEP-Si, nor was the release of leukocyte migration inhibitory factor from sensitized lymphocytes. The possibility of antigen or mitogen competition was excluded. The effects of CEP-Si in vitro were time dependent and did not require the presence of monocytes. Cells pretreated with CEP-Si and then washed suppressed plaque formation by fresh autologous cells in highly stimulated cultures. CEP-Si injected into C57BL/6 mice also strongly suppressed their immune response to sheep erythrocytes, and the in vivo suppression was correlated with the effects of CEP-Si in vitro.
The subgingival placement of any one of the three types of temporary crowns placed on 28 posterior teeth of seven subjects caused no detectable change in the gingiva over a 3 week period. There is a need for further study of the influence of temporary crowns on the different types of gingival tissue.
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We compared an immunochemical method specific for plasma proteins with a chemical method, in which interfering substances are separated by gel filtration and "total" urinary protein is determined by the biuret reaction followed by reaction of protein-bound copper with diethyldithiocarbamate after a second gel filtration to remove nonprotein-bound copper. More than 250 24-h urine samples were analyzed by each method. There was linear agreement and a correlation of 0.96 between the two methods, but urinary protein values determined by the immunochemical method, especially for patients with multiple myeloma, were lower than by the chemical method.