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Biomedical subjects

J James

Publications and source records attributed to J James.

At least 19 recordsLinked to original sources
PubMed1992

Community involvement towards community objectives.

The World Health Organisation "Health for all children by the year 2000" declaration presents an exciting yet timely challenge. If these aims are to be achieved, the role of the health worker must be broadened. There must be a recognition that families will determine the true health of their children--physical, mental and social. Families must be able to identify and realise their aspirations, to satisfy their needs and to cope with and adapt to their environments. Only by advocacy, by forming a partnership with families, and by empowering families to exercise greater control over their health and their environment, will health workers begin to see positive change in the community. There is a need to collect and collate data from the community in order that the true needs of families are met. New outcome measures which address "quality of life" must be developed; these will accord closely with the WHO aims, and will enable communities to set the high standards that must be achieved for our children. "Health", interpreted in its broadest meaning, should lead to health professionals concentrating on the promotion of a healthy lifestyle and the attainment of "quality of life". There must be a move away from the "medical model" of care to the empowerment of parents who are responsible for the care for their children and the need to work towards better community resources.

Child↗
PubMed1992

Distribution of xanthine oxidoreductase activity in human tissues--a histochemical and biochemical study.

Localization of the activity of both the dehydrogenase and oxidase forms of xanthine oxidoreductase were studied in biopsy and postmortem specimens of various human tissues with a recently developed histochemical method using unfixed cryostat sections, poly-(vinyl alcohol) as tissue stabilizator, 1-methoxyphenazine methosulphate as intermediate electron acceptor and Tetranitro BT as final electron acceptor. High enzyme activity was found only in the liver and jejunum, whereas all the other organs studied showed no activity. In the liver, enzyme activity was found in sinusoidal cells and both in periportal and pericentral hepatocytes. In the jejunum, enterocytes and goblet cells, as well as the lamina propria beneath the basement membrane showed activity. The oxidase activity and total dehydrogenase and oxidase activity of xanthine oxidoreductase, as determined biochemically, were found in the liver and jejunum, but not in the kidney and spleen. This confirmed the histochemical results for these organs. Autolytic rat livers several hours after death were studied to exclude artefacts due to postmortem changes in the human material. These showed loss of activity both histochemically and biochemically. However, the percentage activity of xanthine oxidase did not change significantly in these livers compared with controls. The findings are discussed with respect to the possible function of the enzyme. Furthermore, the low conversion rate of xanthine dehydrogenase into xanthine oxidase during autolysis is discussed in relation to ischemia-reperfusion injury.

Animals↗
PubMed1992

Modulation of fibrinogen content in cryoprecipitate by temperature manipulation during plasma processing.

In routine blood bank production of single-donation cryoprecipitate, the introduction of a 16-hour hold at 4 degrees C, with the frozen plasma units packed into polystyrene containers, resulted in plasma prethaw temperatures of -4 degrees C to -8 degrees C. This in turn resulted in cryoprecipitate fibrinogen levels that were 214 percent of those obtained when units were thawed immediately after removal from -30 degrees C storage. In scale-model production of factor VIII concentrate, plasma warmed from -30 to -10 to -15 degrees C over 18 hours before pooling and thawing yielded cryoprecipitate fibrinogen levels that were 66 percent of those found in plasma warmed to -2 to -5 degrees C over the same period. Processing -30 degrees C plasma without a warming period led to cryoprecipitate fibrinogen levels that were 40 percent of those obtained from plasma warmed to -2 to -5 degrees C. These differences were accentuated after purification of the cryoprecipitates to an intermediate-purity factor VIII concentrate. These results suggest that simple modifications in production methods allow the fibrinogen content of cryoprecipitate to be tailored to specific uses.

Blood Banks↗
PubMed1992

Red cell and platelet concentrates from blood collected into half-strength citrate anticoagulant: improved maintenance of red cell 2,3-diphosphoglycerate in half-citrate red cells.

This study confirms previous work suggesting equivalent in vitro properties in blood components prepared from donations collected into half-citrate preservative (HCPD) compared to components derived from donations collected into standard citrate-phosphate-dextrose (CPD) preservatives. In addition, red cell products harvested from HCPD donations showed significantly improved maintenance of pH over storage, and this was reflected in improved maintenance of intracellular 2,3-diphosphoglycerate (2,3-DPG). This effect was observed in whole blood and in red cells suspended in a phosphate-containing additive solution (Tuta AAS). Collection into HCPD also improved 2,3-DPG maintenance in red cell concentrates processed following an 18-hour hold at 22 degrees C. These improvements were less pronounced in red cells suspended in a non-phosphate-containing medium (Fenwal Adsol) in which a higher pH was maintained even in units collected in CPD. Platelets harvested from HCPD blood and suspended in plasma showed equivalent quality to platelets from standard donations. Some deterioration of platelet properties was observed when HCPD platelets were stored in a non-citrate synthetic medium. Together with data indicating improved coagulation factor stability, these results suggest that collection into HCPD improves stored blood quality and may also allow logistical benefits in blood component preparation.

2,3-Diphosphoglycerate↗
PubMed1992

Morphologic changes of extrahepatic bile ducts during obstruction and subsequent decompression by endoprosthesis.

The morphologic changes of the extrahepatic biliary tract during obstruction and the effects of biliary decompression by means of an endoprosthesis on the bile duct wall were studied by light microscopy and scanning electron microscopy. Common hepatic duct biopsy specimens and bile cultures were obtained during surgery from 30 patients with a distal common bile duct obstruction caused by a tumor. Thirteen patients had obstructed bile ducts of 3 weeks' duration (group A). Seventeen patients had had jaundice for a period of 4 weeks and had subsequently undergone preoperative endoscopic biliary stenting for a period of 4 weeks (group B). Three autopsy specimens from patients without hepatobiliary disease served as controls. The results showed that the initial dilatation and thickening of the obstructed ducts in group A were associated with a mild inflammation, a moderate degree of fibrosis, and local epithelial disintegration. The presence of an endoprosthesis, however (group B), induced severe inflammatory changes with considerable fibrosis and ulcerative lesions, resulting in markedly thickened ducts with lumina approximating the diameter of the stent. Three of 13 (24%) bile cultures in group A were positive and 14 of 17 (82%) in group B were positive.

Bile Duct Neoplasms↗
PubMed1990

Use of plasma with high levels of ionised calcium in the production of model scale coagulation factor concentrates.

We have attempted to exploit the Ca2(+)-dependent stability of factor VIII in producing factor VIII concentrates of higher yield. Plasma levels of ionised calcium were increased in two ways: (a) whole blood collection into half-strength citrate CPD anticoagulant, leading to free Ca2+ levels of ca 120 microM and (b) apheresis collection of plasma which was then recalcified to free Ca2+ levels of ca 300 microM under heparin cover. Coagulation factor concentrates were prepared using model versions of our industrial scale manufacturing methods. Factor VIII yield was increased through low citrate collection. This did not compromise factor IX yield or thrombogenic potential. Use of recalcified heparinised plasma did not lead to any improvement in factor VIII yield and resulted in a marked drop in factor IX recovery, possibly from interference by heparin of factor IX binding in ion-exchange chromatography. The benefits accruable through the use of half-strength citrate CPD anticoagulant support the continued evaluation of this preservative in large scale blood collection and fractionation. The deleterious effects of heparin in charge-mediated plasma fractionations may pose serious difficulties in harvesting vitamin K dependent factors.

Anticoagulants↗
PubMed1990

Elastic and collagenous fibers in the temporomandibular joint capsule of the rabbit and their functional relevance.

This study deals with the form and function of the temporomandibular joint capsule and compares the histological structure of the capsule and kinetics of condylar and disc movement in rabbit and man. The morphology of the capsule of the jaw joint of the rabbit was studied by means of histological sections of isolated capsules, celloidin sections of decalcified heads, and cryostat sections containing the joint, fixed in jaw open and closed positions. General staining methods and selective methods for elastin and collagen were used. The volume density of the elastic fibers was determined morphometrically. The capsule consists of a portion connecting disc and skull and a portion connecting disc and mandible. The former portion has a fibrous outer layer of dense connective tissue. It contains numerous bundles of specifically oriented collagen but hardly any elastic fibers. Few irregularly arranged elastic fibers are present in the lateral and medial areas of the capsule. In contrast, the portion connecting disc and condylar process contains not only oriented collagen but also large amounts of elastic fibers. Anteriorly, there is a thin elastic band that is stretched greatly at jaw opening. Posteriorly, the capsule takes the appearance of a large fibro-elastic pad that covers the posterior extension of the condyle. This part is somewhat stretched when the jaw is closed. The findings correlate well with the results of jaw movement studies, showing a remarkable capability for condylar protrusion and retrusion. In contrast to the situation in humans, this movement occurs mainly between condyle and disc. It is made possible by the rather tight connections between skull and disc and flexible ones between disc and condyle.

Animals↗
PubMed1990

Immunocytochemical determination of ploidy class-dependent bromodeoxyuridine incorporation in rat liver parenchymal cells after partial hepatectomy.

Immunocytochemistry of bromodeoxyuridine (BrdU) incorporated in DNA was performed on cryostat sections of rat liver and on isolated hepatocytes after partial hepatectomy using a two-step labeling technique. The method enabled the detection of S-phase nuclei in both tissue preparations. Quantification of the number of labeled nuclei in sections showed that the number of nuclei in S-phase increased from 0.3% in control liver to about 36% at 24 h after partial hepatectomy. The detection of BrdU in isolated hepatocytes showed the same labeling index of binuclear diploid, mononuclear tetraploid and binuclear tetraploid cells. A special role for mononuclear diploid cells in proliferation did not seem to occur.

Animals↗