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Biomedical subjects

S Barber

Publications and source records attributed to S Barber.

35 records · Page 2Linked to original sources
PubMed1984

Platelet cryopreservation. 1. In vitro aggregation studies.

Platelets were harvested by a Hemonetics Model-30 discontinuous cell separator from 20 normal volunteers and were cryopreserved in the presence of 5% DMSO at a controlled rate of freezing of -1 degrees C/min and stored in liquid nitrogen for up to 3 months. A significant loss of platelets occurred at the platelet concentration step through adhesion of platelets to the bag walls. A small reduction in aggregation associated with this was also seen and may reflect some damage to the platelets during the pheresis procedure. A small, but significant loss of platelet aggregation was seen with all agents following cryopreservation. Mean percentage aggregation post-thaw for all the agents was 75.4% (range 74-78%) and platelet recovery was approximately 90%. No significant changes in aggregation or recovery were seen over the 3 months' storage period. The cryoprotectant DMSO was shown to have no deleterious effect on platelet function in vitro.

Blood Platelets↗
PubMed1984

Fibrinogen Adelaide: a familial hypodysfibrinogenaemia associated with abnormal alpha chains.

A familial hypodysfibrinogenaemia occurring in four females with occasional haemorrhagic problems in an Adelaide family was investigated. Affected family members had slightly prolonged thrombin time, prothrombin time and Reptilase time tests, and apparently elevated levels of fibrin degradation products (FDPs). Fibrinogen assessed by reactivity with thrombin (Clauss method) was significantly less than fibrinogen determined by various other methods, though even by immunoquantitation fibrinogen levels were only slightly above half normal in affected family members. Isoelectric focussing (IEF) of the reduced patient's fibrinogen in urea/polyacrylamide gel revealed minor components with higher isoelectric points (pI) than present in normal fibrinogen or fibrin. These were shown to have a molecular weight similar to the alpha chain of fibrin by subsequent sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The abnormal species tended to remain in plasma after clotting with Reptilase or thrombin although polymerization of the clotted fibrin was normal. The magnitude of the pI shift relative to normal fibrin alpha chain indicated an increased positive charge on the abnormal species.

Adult↗
PubMed1984

Surface markers of human gingival fibroblasts in vitro. Characterization and modulation by enzymes and bacterial products.

Surface markers of human gingival fibroblasts in vitro were investigated using monoclonal and heterologous antisera against a range of cell surface antigens, together with rosetting techniques to characterize surface receptors for IgG and C3. WI-38 fibroblasts and human peripheral blood monocytes were used as control cells. Human gingival fibroblasts exhibited complement receptors and beta2-microglobulin, as did WI-38 cells. Ten per cent of the human gingival fibroblasts were positive for HLA-DR antigens and additionally exhibited a granulocyte antigen not apparent on WI-38 cells. Monolayers of the gingival fibroblasts were further exposed for short periods to varying concentrations of enzymes (trypsin, collagenase and neuraminidase), bacterial extracts (lipopolysaccharide and lipoteichoic acid) and crude supra- and subgingival plaque sonicates. Surface-marker analysis was then carried out. The most noticeable effects were obtained with Vibrio cholerae neuraminidase which enhanced C3 receptor and surface antigen expression, and supragingival plaque sonicate which depressed the expression of HLA-DR and granulocyte antigens while not affecting beta2-microglobulin expression. Trypsin reduced antigen expression to a degree, but its effects were mainly on cell adherence.

Antigens, Surface↗
PubMed1984

Congenital anti-thrombin III deficiency with mesenteric venous thrombosis--functional and immunological estimations.

Familial antithrombin III (AT III) deficiency, with mesenteric venous thrombosis, is reported in an Australian family. Antithrombin III was assayed chromogenically, fluorometrically, and immunologically. The deficiency was further analysed using crossed-immunoelectrophoresis. It is suggested that when AT III deficiency is suspected, both a functional and an immunological assay should be performed.

Adolescent↗
PubMed1980

Familial association of the lupus anticoagulant.

A lupus anticoagulant was detected in plasma from two pairs of siblings using the kaolin clotting time mixing test. Strong evidence for this inhibitor in one further sibling pair is presented. Although coagulation abnormalities are usually classified as either acquired or of genetic origin it is apparent that the lupus anticoagulant might often be an acquired coagulation defect requiring genetic predisposition.

Adolescent↗
PubMed1978

A near haploid clone: 24,XY, t (9; 22) (q34; q11) from a patient in blast crisis of chronic myeloid leukaemia.

Chromosome studies on bone marrow in a patient with chronic myeloid leukaemia (CML) revealed a mosaic picture with a dominant clone of 24,XY, t(9; 22) (q34; q11). This corresponded to a preponderance of minute blasts in smears of bone marrow aspirate. It is suggested that a haploidy event rather than progressive hypodiploid loss, is responsible for the genesis of the miniature blast cells.

Bone Marrow↗
PubMed1975

Adequate dialysis.

Regular haemodialysis with the Kiil dialyser for 8-10 h three times a week is the present standard of adequate dialysis. In 100 patients treated by this regime there was no positive correlation between plasma urea and creatinine before or after dialysis and any of the symptoms of which these patients still complained. There are no grounds for believing that a further increase in dialysis would relieve residual symptoms. However, any reduction in current standards of dialysis should be justified by prolonged clinical trial of large groups of patients before they are accepted as equivalent in view of the infrequency of some uraemic manifestations such as pericarditis. The implications of the middle molecular hypothesis are discussed.

Adult↗
PubMed1975

Identity, release, and binding of mitochondrial-bound hexokinases in mammary glands and adenocarcinomas of lactating mice.

The mitochondrial-bound hexokinases (adenosine triphosphate:D-hexose 6-phosphotransferase) of mammary adenocarcinoma and of normal gland were compared in lactating C3H mice. Treatment of mitochondria isolated from both the normal and neoplastic tissue with 0.5 m NaCl or 0.1 mM glucose 0-phosphate effected the release of about 50% of the bound hexokinase. In the presence of magnesium ion, enzyme from either source attached to mitochondria from either tissue and in all combinations to the same extent. Identification of the isoenzyme complement in the mitochondrial extract by diethylaminoethylcellulose chromatography revealed only types I and II. In the tumor, the hexokinase activity in both the cytosol and the fraction solubilized from mitochondria was predominantly in the form of type I ( 60%). In contrast, the activity released from mitochondria isolated from normal gland was predominately type II, while the cytosol contained almost equivalent amounts of types I and II. While this difference does not explain differences in glucose utilization between the normal and neoplastic tissue, it may provide a means of distinguishing between the two.

Animals↗
PubMed1967

Lipid composition of the vascular system during infancy, childhood, and young adulthood.

The object of this study was to determine the changes in lipid composition that occur in blood vessels from infancy to young adulthood. Analyses included levels of total cholesterol, total triglyceride, phospholipid, and cholesteryl ester fatty acids, and the distribution of saturated and unsaturated fatty acids. Triglyceride, total and monoenoic fatty acids, and linoleic acid were lower in the ascending, thoracic, and abdominal aorta than in the pulmonary artery and inferior vena cava. Phospholipids and arachidonic acid were higher in aortic segments than in the other two vessels. Aortic lipids showed significant changes with increasing age: total cholesterol and total fatty acids decreased from <1 wk to 5 yr, then increased to 22 yr of age. Triglycerides decreased whereas cholesteryl esters increased from 10 to 22 yr of age. Saturated fatty acids decreased from 1 wk to 10 yr, then remained relatively constant. Linoleic acid (3.7-9.8% of total fatty acids) and arachidonic acid (15.8-21.7%) both increased with age; the increase in cholesteryl linoleate was highly significant. After 10 yr of age, total cholesterol and total fatty acids were significantly higher in abdominal than in ascending and thoracic segments of aorta.

Adolescent↗
PubMedDate not supplied

Early knee motion after open and arthroscopic anterior cruciate ligament reconstruction.

The hypothesis proposed in this study was that the initiation of active and passive knee motion within 48 hours of major intraarticular knee ligament surgery would not have the deleterious effects of increasing knee effusion, hemarthrosis, periarticular soft tissue edema, and swelling. We conducted a prospective study with randomized assignment of 18 patients into two groups: 9 patients in the "motion" group began 10 hours of daily continuous passive motion (CPM) on the 2nd postoperative day, while the remaining 9 in the "delayed motion" group used a soft hinged knee brace with knee hinges locked at 10 degrees of flexion and entered into the motion program on the 7th postoperative day. All knees were allowed full 0 degrees to 90 degrees of motion except for a total of seven knees with concomitant mensicus repairs and extraarticular reconstructions where 20 degrees to 90 degrees of motion was allowed, limiting the last 20 degrees of knee extension for the first 4 postoperative weeks to protect the repair. In all other respects, the rehabilitation program after surgery was the same for the two groups, including postoperative compression dressings, exercises, and weight-bearing status. Ten of the eighteen patients had acute ACL disruptions and 8 had chronic ACL insufficiencies. There was an even distribution of acute and chronic knee cases and of open and arthroscopic ligament procedures in the early and delayed motion groups. Associated surgery included four meniscus repairs, three medial collateral ligament repairs, and one lateral collateral ligament repair. Special suturing and fixation techniques were used at surgery to maintain the integrity of ligament and meniscus structures, allowing the surgeon to feel safe in subjecting the joint to early postoperative motion. The objective parameters measured were KT-1000 arthrometer measurements, Cybex isokinetic testing, girth measurements at four lower limb locations, range of motion goniometer measurements, postoperative pain medications, and days of hospitalization. Starting intermittent passive motion on the 2nd postoperative day did not increase joint effusion, hemarthrosis, or soft tissue swelling. In both motion groups, postoperative joint effusions were absent after the 14th postoperative day. There was no statistically significant difference in knee extension or flexion limits, pain medication used, or hospital stay in comparing the two knee motion programs. An important finding of this study was the significant decreases in thigh circumference that occurred within the first few weeks of surgery, which progressed despite a closely supervised inpatient and outpatient rehabilitation program.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗