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Biomedical subjects

B Turner

Publications and source records attributed to B Turner.

At least 73 records · Page 4Linked to original sources
PubMed1990

Lipid binding to gastric mucin: protective effect against oxygen radicals.

Gastric mucus forms a viscous gel overlying the gastric mucosa and is thought to protect the underlying mucosa from noxious agents such as acid, proteases, and bile salts. A common property of mucin, the principal glycoprotein in mucous secretions, is its ability to bind lipids. The purpose of this study was to determine if lipids bound to gastric mucin protect the mucin from oxygen radical attack. Pig gastric mucin, partially purified by Sepharose 4B gel chromatography, was found to contain large amounts of free fatty acids and cholesterol as well as lesser amounts of sphingomyelin and phospholipids. Purified mucin obtained by density-gradient ultracentrifugation in a CsCl gradient contained only trace amounts of fatty acids but no other lipids. Exposure to the oxygen radical-generating system iron/ascorbate caused a marked reduction in viscosity of purified mucin but did not affect partially purified mucin, suggesting that bound lipids shielded the mucin from attack by oxygen radicals. Using discontinuous sucrose-gradient ultracentrifugation in the presence of liposomes containing [3H]palmitic acid, we demonstrated that mucin is capable of binding fatty acids. We also observed a striking increase in solution viscosity of gastric mucin at low pH, a feature that might contribute to the ability of mucin to form a protective diffusion barrier for the underlying epithelium.

Animals↗
PubMed1990

Initial CT findings in 753 patients with severe head injury. A report from the NIH Traumatic Coma Data Bank.

In this prospective multicenter study, the authors have examined data derived from the initial computerized tomography (CT) scans of 753 patients with severe head injury. When the CT findings were related to abnormal intracranial pressure and to death, the most important characteristics of the scans were: midline shift: compression or obliteration of the mesencephalic cisterns: and the presence of subarachnoid blood. Diffuse hemispheric swelling was also found to be associated with an early episode of either hypoxia or hypotension.

Brain Injuries↗
PubMed1987

Oxygen radicals stimulate guinea pig gallbladder glycoprotein secretion in vitro.

In several animal models of cholelithiasis, and in humans with gallstones, hypersecretion of gallbladder mucin is observed. This study was undertaken to determine the effect of oxygen radicals on guinea pig gallbladder glycoprotein secretion in organ culture. Mucosal explants were incubated with [3H]glucosamine hydrochloride to label glycoproteins, then exposed to oxygen radicals generated by chelated ferric iron and ascorbic acid. Marked stimulation of glycoprotein release was observed after a 30-min exposure to the oxygen radical-generating system, and the effect was inhibited by mannitol. The stimulatory effect of hydroxyl radical was not accompanied by leakage of intracellular lactate dehydrogenase. Parallel experiments with human granulocytes activated with f-Met-Leu-Phe and coincubated with gallbladder explants revealed similar results. These results indicate that oxygen radicals, especially the hydroxyl radical (OH.), are capable of stimulating rapid release of mucous-type glycoproteins from gallbladder epithelium.

Animals↗
PubMed1986

Gallbladder prostaglandins and lysophospholipids as mediators of mucin secretion during cholelithiasis.

Mucin hypersecretion from the gallbladder epithelium contributes to cholesterol gallstone formation by accelerating the nucleation of cholesterol-supersaturated bile. Prostaglandins (PGs) and lysophosphatidylcholine (LPC) have both been implicated as potential mediators of mucin hypersecretion, but their roles are unclear. We fed prairie dogs a lithogenic diet (0.34% cholesterol), and after 1, 2, 4, or 6 wk of cholesterol feeding, we measured glycoprotein and LPC concentrations in bile and PG synthesis in gallbladder and liver slices. Hypercholesterolemia and cholesterol supersaturation of bile occurred after 1 wk of cholesterol feeding, but marked crystal formation was delayed until 4 wk, when glycoprotein concentrations became markedly elevated. Glycoprotein hypersecretion was preceded by increased synthesis of PGF2 alpha (P less than 0.002), PGE2 (P less than 0.001), prostacyclin (P less than 0.05), and thromboxane (P = 0.07) in the gallbladder after only 2 wk of cholesterol feeding, but PG synthesis in the liver remained unchanged (P greater than 0.14). LPC concentrations in gallbladder bile also increased at 2 wk (P less than 0.02), but LPC in hepatic bile was unchanged (P = 0.35). In organ culture studies, LPC caused a dose-dependent stimulation of [3H]glycoprotein release from guinea pig gallbladder mucosa that could not be explained solely by LPC's detergent properties. We conclude that gallbladder PG synthesis and LPC production are increased at an early stage of cholesterol gallstone formation in the prairie dog model. These changes probably play a significant role in gallstone pathogenesis, since they mediate hypersecretion of gallbladder mucin and thus favor the nucleation of cholesterol-supersaturated bile.

Animals↗
PubMed1985

Neoplasia in immunosuppressed renal transplant patients: a 20-year experience.

This review examines a 20-year experience in renal transplantation at our center to determine the effects of immunosuppression on the subsequent development of malignancies. Twenty patients had 21 malignancies from primary sites other than skin, yielding an incidence of 2.5%. There were 0.65 malignancies for each 100 cumulative patient years of immunosuppression. Suppression of the host immune response is associated with an increased incidence of malignancies.

Adolescent↗
PubMed1985

Circulation of influenza viruses and paramyxoviruses in waterfowl originating from two different areas of North America.

Migratory waterfowl and shore birds harbour a wide range of influenza viruses, some of which have been implicated in influenza outbreaks in mammals and domestic birds. In the present study, a comparison was made of two marshalling areas for different migratory flyways of waterfowl in North America over a 6-8-year period. Virtually all known influenza subtypes were isolated and the predominant subtype changed from year to year. A marked difference between the two locations was that the predominant subtypes circulating were never the same, even though in both areas, most virus isolations were made from the same duck species (mallard duck). Isolations of paramyxovirus were characterized mainly as avian PMV-1.Viruses isolated from ducks included those antigenically related to viruses causing disease in birds and mammals, although the viruses did not necessarily appear in ducks immediately before they appeared in other species. For example, H5N2 isolates antigenically related to the virus causing severe disease outbreaks in chickens in the USA in 1983, were detected in ducks from both areas at different times (1976, 1980 and 1982). These studies indicate that ducks in different areas represent a continual source of orthomyxoviruses and paramyxoviruses of potential disease significance to other species.

Alberta↗
PubMed1984

Immunofluorescent detection of histone 2B on metaphase chromosomes using flow cytometry.

A monoclonal antibody against histone 2B (anti-H2B) was used as a reagent to stain isolated chromosomes for analysis using flow cytometry. Chromosome suspensions were treated with a mouse monoclonal antibody specific for the histone 2B (clone HBC-7) and then with a fluorescein-labeled goat anti-mouse-IgM antibody. The chromosomes were also stained for DNA content with either Hoechst 33258 or propidium iodide. The amount of antibody and the amount of DNA-specific stain bound to each chromosome were measured simultaneously using flow cytometry. The order of the steps in the staining protocol is important. Propidium iodide prevents anti-H2B from binding to chromosomes, and therefore must be added only after antibody labeling is completed. In contrast, the addition of Hoechst 33258 before antibody labeling reduces antibody binding by only 20%-30%. Binding of anti-H2B was proportional to the DNA content of both human and Chinese hamster chromosomes. Human chromosomes bind an average of three to four times more anti-H2B than do Chinese hamster or mouse chromosomes of the same DNA content. This was determined by analyzing mixtures of human and Chinese hamster chromosomes and human and mouse chromosomes. The results demonstrate that it is possible to label the proteins of chromosomes in suspension with fluorescent antibodies and to use these reagents for the analysis of chromosome structure by flow cytometry.

Animals↗
PubMed1982

Blood parasites of prairie anatids and their implication in waterfowl management in Alberta and Saskatchewan.

Information on the blood parasites occurring in 3,866 anatids of 14 species collected from five locations in Alberta and Saskatchewan during 1976-80 is summarized. An overall prevalence of 26% with avian hematozoa was recorded. Leucocytozoon simondi was the most frequently encountered parasite, occurring in 17% of the ducks; Haemoproteus nettionis was observed in 11% of the birds while Plasmodium circumflexum and microfilariae (probably of Splendidofilaria fallisensis) occurred in only 2% and less than 1% of the sample respectively. Overall prevalence of infection in both immatures and adults was similar, although the sample was heavily biased in favor of the immature age class. While the overall prevalence of L. simondi was similar in both age classes, H. nettionis occurred twice as frequently in the adult birds. Infection prevalences of birds in the five geographic areas sampled were different and these differences are discussed. Prevalences also differed from year to year in birds from the various areas and these differences are attributed, in part, to the water levels encountered each year. Leucocytozoon simondi is considered a potentially limiting factor for waterfowl production in some areas of northern Alberta and Saskatchewan.

Age Factors↗
PubMed1981

Blood parasites of trumpeter swans, Olor buccinator (Richardson), from Alberta.

A total of 75 trumpeter swans (Olor buccinator (Richardson) from the Grande Prairie region of Alberta was examined for hematozoa; 26 (34.6%) swans were infected with Haemoproteus nettionis. A single infection of Leucocytozoon simondi and two of Plasmodium circumflexum also were recorded. Local, second year (SY) and adult (AHY) female swans had closely similar rates of hematozoan infection; the SY and AHY male swans had substantially higher infection rates than other subgroups.

Age Factors↗
PubMed1980

Disarming the bluebottle: treatment of Physalia envenomation.

Clinical tests of the efficacy of various treatments of bluebottle (Physalia physalis) stings were conducted on 20 volunteers. Vinegar and aluminium sulphate solution (Stingose) gave a significant reduction in pain 15 minutes after application when compared with the control sites which were treated with sea water. The application of methylated spirits caused a significant increase in pain compared to salt water.

Acetates↗