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Biomedical subjects

C May

Publications and source records attributed to C May.

At least 19 recordsLinked to original sources
PubMed2000

The N-terminal beta-barrel structure of lipid body lipoxygenase mediates its binding to liposomes and lipid bodies.

Phospholipase A2 and a particular isoform of lipoxygenase are synthesized and transferred to lipid bodies during the stage of triacylglycerol mobilization in germinating cucumber seedlings. Lipid body lipoxygenase (LBLOX) is post-translationally transported to lipid bodies without proteolytic modification. Fractionation of homogenates from cucumber cotyledons or transgenic tobacco leaves expressing LBLOX showed that a small but significant amount was detectable in the microsomal fraction. A beta-barrel-forming N-terminal domain in the structure of LBLOX, as deduced from sequence data, was shown to be crucial for selective intracellular transport from the cytosol to lipid bodies. Although a specific signal sequence for targeting protein domains to the lipid bodies could not be established, it was evident that the beta-barrel represents a membrane-binding domain that is functionally comparable with the C2 domains of mammalian phospholipases. The intact beta-barrel of LBLOX was demonstrated to be sufficient to target in vitro a fusion protein of LBLOX beta-barrel with glutathione S-transferase (GST) to lipid bodies. In addition, binding experiments on liposomes using lipoxygenase isoforms, LBLOX deletions and the GST-fusion protein confirmed the role of the beta-barrel as the membrane-targeting domain. In this respect, the cucumber LBLOX differs from cytosolic isoforms in cucumber and from the soybean LOX-1. When the beta-barrel of LBLOX was destroyed by insertion of an additional peptide sequence, its ability to target proteins to membranes was abolished.

Binding Sites↗
PubMed1999

Medical knowledge and the intractable patient: the case of chronic low back pain.

Chronic low back pain (CLBP) is endemic in Western societies, and while a good deal of attention has been paid to the lay experience of such pain, much less sociological attention has been paid to the way in which medical ideas about it have been formulated. This paper takes the latter course, tracing the development of clinical notions about the relationship between pathological signs and expressed symptoms from the 1820's to the 1930's, and then placing these developments in the context of postwar notions of 'somatization'. We point to the extent to which the disparity between expressed symptoms, pathological signs and perceived disability in CLBP has led to the moral character of the sufferer forming a constant subtext to medical discourse about the condition. We also note the extent to which medical ideas themselves have been constructed in intimate linkage with socio-legal questions of compensation and worker's insurance.

Attitude of Health Personnel↗
PubMed1999

Methotrexate resistance conferred by transplantation of drug-resistant transgenic marrow cells fractionated bycounterflow elutriation.

Introduction of genes conferring drug resistance into hematopoietic cells may allow for improved chemotherapy by protection of normally drug-sensitive cells from the toxic side-effects of antitumor agents. We recently reported that transplantation of murine marrow transgenic for drug-resistant dihydrofolate reductase (DHFR) protected mice from lethal doses of methotrexate (MTX), demonstrating the feasibility of imparting drug resistance to recipients of marrow expressing drug-resistant DHFR activity. In order to optimize this strategy it is necessary to identify the hematopoietic cell populations which mediate drug resistance. For this purpose, we separated committed progenitor populations from primitive hematopoietic cells in DHFR transgenic marrow by counterflow elutriation (CE). As expected, supplementation with a fraction containing committed progenitors afforded protection from MTX-induced aplasia observed early after transplantion in animals administered MTX. In contrast, supplementation with a fraction containing primitive hematopoietic cells depleted of committed progenitors failed to provide immediate protection from early aplasia, but instead contributed to drug resistance 4 to 5 weeks after transplantation. The presence of primitive hematopoietic progenitors in both fractions was evident from Southern hybridization analysis for donor transgenic cells 2 months post-transplant. We conclude that protection from aplasia associated with MTX administration immediately after transplantation requires expression of drug-resistant DHFR activity in more differentiated, committed hematopoietic cells, while primitive DHFR transgenic progenitors contribute to long-term drug resistance. These results help to define the appropriate target cells for improved chemotherapy by protection of hematopoietic cells through the introduction of new genes conferring drug resistance.

Animals↗
PubMed1999

Incontinence and sexuality: findings from a qualitative perspective.

Incontinence remains a taboo where myths and misconceptions abound. The objectives of this study were to explore the impact of incontinence on an individual's sexuality and to identify the impact of health interventions for the management of incontinence on sexuality. A quota sample of subjects whose incontinence was regarded as being either successfully managed (n = 14) or unsuccessfully managed (n = 12) by continence advisers, community nurses and health visitors from two National Health Service Trusts were interviewed. A further subject whose incontinence was not classified was also interviewed, bringing the total number of interviews to 27. One Trust had an established continence advisory service of some 19 years, while the other Trust did not have a specific continence advisory service and relied upon members of the primary health care team to meet the needs of individuals suffering from incontinence. The qualitative data from this study were analysed using the constant comparative technique and were grouped into themes relating to clothing and appearance, intimacy and caring, management techniques and relationships and life trajectory. This is the first study to have examined management techniques for incontinence and their relationship to an individual's sexuality and therefore has important implications for clinical practice. It has also set the findings of incontinence and sexuality in the context of chronic conditions and their related patient careers and life trajectory.

Adult↗
PubMed1999

Chronic low back pain in general practice: the challenge of the consultation.

BACKGROUND: Chronic low back pain (CLBP) is a symptom commonly presented to GPs, accounting for a significant proportion of their workload. It is also a common reason for sickness absence, and thus of national economic importance. OBJECTIVES: This qualitative study aimed to provide an understanding of how GPs understood CLBP, how they approached the consultation with CLBP patients and how they conceptualized the management of this problem. METHOD: Qualitative research techniques were employed. Twenty GPs working in North-West England were interviewed. Interviews were semi-structured and recorded on audio-tape. Transcripts of these interviews were then subjected to constant comparative qualitative analysis. RESULTS: Subjects described their difficulties in responding to and managing CLBP. They acknowledged the link between CLBP and psychological distress, and that it legitimizes long-standing illness behaviour. They were pessimistic about the chances for successful cure or palliation of CLBP. CONCLUSION: Subjects seemed to be cognisant of collusion between doctor and patient, in cases where the patient's explanatory model of back pain is not challenged. We argue that this can be accounted for by the patient operating within a physical model of pain causation, while doctors operate using a model that stresses psychosocial factors. The incommensurability of these models lies at the root of the CLBP consultation as a problem.

Chronic Disease↗
PubMed1998

A phospholipase A2 is transiently synthesized during seed germination and localized to lipid bodies.

A patatin-like protein is present in the storage tissue of cucumber seedlings during the stage of fat mobilization. The cucumber protein is a homologue of a glycoprotein which in potatoes accounts for most of the total protein content of tubers. Following preparation of a cucumber cDNA library representing the developmental stage of cotyledons of 1 day old germinating seeds we isolated and characterized a clone encoding a patatin-like protein. Antibodies raised against the protein expressed in bacteria were used for immunodetection in subcellular fractions of cucumber seedlings. It was shown that the patatin-like protein was virtually exclusively confined to lipid bodies. The protein expressed in bacteria was characterized in vitro by its esterase activity acting on monoacylglycerols and phospholipids. Detailed analysis using various forms of phosphatidyl choline as substrates demonstrated that the patatin-like protein is a phospholipase A2 acting on palmitoyl, linoleoyl and hydroperoxidized linoleoyl groups equally well. Studying the temporal and tissue-specific expression of patatin-like protein mRNA we showed its appearance exclusively during fat catabolism. As maximal amounts of the protein were found at an early stage of mobilization and confined to lipid bodies, we propose that the patatin-like hydrolase is involved in lipid body mobilization.

Amino Acid Sequence↗
PubMed1998

Matrix metalloproteinases 2 and 9 in canine rheumatoid arthritis.

Matrix metalloproteinases (MMPs) are considered important mediators of tissue damage in joint diseases. The levels of MMPs 2 and 9 were measured in samples of synovial fluid from 20 joints in seven dogs with rheumatoid arthritis by gelatin zymography. The results were compared with the actual gelatinolytic activity of the fluid measured in a gelatin-degradation ELISA. The gelatinolytic activity in synovial fluid from arthritic joints was markedly greater than that in fluid from disease-free joints. The zymographic activity attributable to MMP-9 (identified by Western blotting) was absent from synovial fluid from control joints but prominent in fluid from arthritic joints, and in these joints the presence of a 75 kDa form of MMP-9 was correlated with the gelatinolytic activity of the fluid measured by the ELISA (r = 0.81, P < 0.05). Synovial fluid from one dog with rheumatoid arthritis was examined before and after treatment with corticosteroids. After treatment its zymographic pattern had returned to normal.

Adrenal Cortex Hormones↗
PubMed1998

Management of disc-associated wobbler syndrome with a partial slot fenestration and position screw technique.

A previously unpublished surgical technique for the management of disc-associated wobbler syndrome is described. A series of 17 middle-aged dobermanns (mean age 7.4 years) with this condition were managed by a technique of partial slot fenestration and position screw fixation of the affected disc space (C6/7 in all cases). One patient was lost to follow-up and, of the remaining 16 cases, 13 improved following surgery (81 per cent). The three failures were a consequence of incorrect placement of one of the screws. Careful evaluation of immediate postoperative radiographs allows this problem to be identified; the screw can then be correctly repositioned with an immediate return to surgery.

Animals↗
PubMed1998

Development of a toxin-binding agent as a treatment for tunicaminyluracil toxicity: protection against tunicamycin poisoning of sheep.

OBJECTIVE: To assess the ability of certain derivatives of beta-cyclodextrin to treat sheep affected by tunicaminyluracil toxicity, using tunicamycin poisoning as a model system. DESIGN: Controlled treatment trial. ANIMALS: One hundred and sixty Merino wethers were used in the studies. PROCEDURE: Groups of sheep were experimentally poisoned with tunicamycin. Derivatives of beta-cyclodextrin, with or without magnesium sulphate and magnesium gluconate, were administered to treatment groups daily for 2 to 3 days. Treatment groups were compared with untreated groups in terms of survival. RESULTS: A significant increase in survival was observed following treatment of tunicamycin-affected sheep with hydroxypropyl-beta-cyclodextrin (HP beta-CD) and magnesium sulphate in solution (P < 0.05). In subsequent trials, formulation of the cyclodextrin in the form of a magnesium gluconate gel suspension demonstrated significant protection (P < 0.01) and was equally as effective as the cyclodextrin in solution, but required half the frequency of administration, even when the treatment was not commenced until 24 h after the final toxin dose. Beta-cyclodextrin-epichlorohydrin copolymer also improved the survival rate. After toxin administration, the sheep lost significantly less weight if treatment with HP beta-CD was commenced early (P < 0.001). CONCLUSION: Protection studies using these two beta-cyclodextrin derivatives suggest that they may be effective in increasing the survival of sheep poisoned by tunicamycin and warrant further testing in field outbreaks of annual ryegrass toxicity.

Animals↗