Biomedical subjects

J Baker

Publications and source records attributed to J Baker.

363 records · Page 21Linked to original sources

PubMedDate not supplied

Ceramide glycanase from rat mammary tissues: inhibition by PPMP(D-/L-) and its probable role in signal transduction.

A ceramide glycanase (CGase activity has been characterized from lactating rat mammary tissue which cleaves the glycosidic bond between sphingosine and the glucose chain of a glycosphingolipid (GSL) thus liberating the intact oligosaccharide chain from a GSL. The majority (65%) of the hydrolase activity was detected in the supernatant fraction when the rat mammary tissue homogenate was centrifuged at 100,000 x g. Attempts to purify the enzyme indicated that the CGase protein is of hydrophobic nature as it binds to hydrophobic columns. The enzyme has been partially purified using hydrophobic columns in tandem. The partially purified protein was found to be immunoreactive to the antibody raised against the purified clam CGase. The immunostained band corresponded to a 64 kDa protein as also found with the clam enzyme. This immuno cross-reactivity indicated probable structural similarities between CGase proteins isolated from widely separated species in the evolutionary tree. The rat CGase was found to have a specific detergent requirement for optimal activity, and the pH optimum was found to be between 5 and 6. The enzyme activity is partially heat stable. It is not a divalent cation requiring enzyme; however, the activity is totally inhibited in the presence of mercury, indicative of a sulfhydryl group in the active site of the enzyme. The rat mammary CGase activity is inhibited in the presence of both D- and L-PPMP (1-phenyl-2-hexadecanoylamino-3-morpholino-1-propanol. HCl), homologs of PDMP (1-phenyl-2-decanoylamino-3-morpholino-1-propanol. HCl), a well-known inhibitor of GlcT-1 (Ceramide: UDP-Glc Glucosyltransferase), an enzyme in the glycolipid synthetic pathway. The inhibition seems to be of a competitive nature and the same type of inhibition is also observed with clam CGase. The CGase activity was found to be highest in lactating tissue compared to the activity found in either pregnant or post-lactating rat mammary tissues. Tissue survey indicated the presence of high levels of CGase in lactating rat liver, uterus, and ovary; moderate activity was detected in kidney and spleen. Both virgin and male rat mammary tissue also indicated a basic level of CGase activity. However, newborn spleen and mammary tissue showed a comparable level of activity to that found in lactating rat tissues. This report is mainly concerned with the characterization of CGase activity from a mammalian source and its importance in cellular processes.

Animals↗

PubMedDate not supplied

Evidence-based practice in pressure sore reduction.

A two-year project at Chase Farm Hospitals NHS Trust to promote evidence-based practice in pressure sore prevention resulted in a steady reduction in the number of hospital-acquired pressure sores. The pooling of resources by a wide variety of staff with a diverse range of knowledge and experience resulted in a truly multiprofessional project. The knowledge that working together to implement change can succeed strengthens the chances of success in future work and has brought direct benefits to patient care.

Evidence-Based Medicine↗

PubMedDate not supplied

Blood lipid and lipoprotein concentrations in active, sedentary, healthy and diseased men.

AIM: To examine differences in resting blood lipid and lipoprotein concentrations in male subjects of varying degrees of cardiovascular fitness ranging from the healthy elite athlete to the sedentary subject either with or without angiographically confirmed evidence of coronary artery disease (CAD). METHODS: Two-hundred-and-eighty-four clinically asymptomatic male subjects were selected from a group of Olympic distance runners (n = 1 7), physical education athletes (n = 44), and industrial executives (n = 223). Each subject received a detailed physical examination and provided a venous blood sample after fasting, which was analysed for lipid and lipoprotein concentrations. Maximum oxygen uptake was determined using on-line computerised respiratory analysis during a functional diagnostic test. The industrial executive group was further divided according to their electrocardiographic (ECG) response to exercise; negative ECG (n = 138), positive (abnormal) ECG but no angiographic evidence of CAD (n = 18) and positive ECG with angiographic evidence of significant CAD (n=67). RESULTS: Lipid-lipoprotein profiles were consistently abnormal in subjects with a positive ECG and documented evidence of CAD, whereas those subjects who tested negative or false-positive were less affected. The lipid-lipoprotein profiles observed between Olympic distance runners and an age-matched group of physically active students were not significantly different despite clear differences in physical activity patterns. CONCLUSIONS: In addition to the abnormal lipid-lipoprotein profile in subjects with CAD, the present data also suggest that while physical activity confers metabolic cardioprotection, a threshold stimulus exists beyond which no further benefits can be gained.

Adult↗