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Biomedical subjects

I D Fraser

Publications and source records attributed to I D Fraser.

At least 55 records · Page 3Linked to original sources
PubMed1991

Comparison of platelet-rich plasma collection using the Haemonetics PCS and Baxter Autopheresis C.

We have compared 118 platelet-rich plasma donations collected using the Autopheresis-C Platelet cell (Auto C) with 166 donations using the Haemonetics PCS. The median platelet yield from the Auto C was superior (2.51 vs. 1.54 x 10(11] although collection times differed (60 vs./40 min). There was greater variability in the platelet yield from the Auto C (0.45-5.6 vs./0.26-2.8 x 10(11], but leucocyte contamination was not significantly different. After secondary processing, there was significantly less residual platelet-poor plasma (272 vs. 369 ml). Platelet function assessed during 5 days of storage was satisfactory for both, although platelet aggregation responses to collagen and adenosine diphosphate were superior in the Auto C platelets.

Humans↗
PubMed1990

Platelet concentrates irradiated with ultraviolet light retain satisfactory in vitro storage characteristics and in vivo survival.

We have previously reported that platelet concentrates (PC) may be irradiated with ultraviolet light (UVL) in a cryostorage pack such that mixed lymphocyte reactions (MLR) are abolished whilst satisfactory platelet function is retained during subsequent storage using Fenwal PL-1240 containers. We have now studied both platelet structure and function after irradiation in DuPont Stericell bags which are both UV-permeable and biocompatible. The irradiation dosage was 3000 Joules/m2 of UVL at a mean wavelength of 310 nm; a dose previously shown to abolish MLR. No detriment to platelet function was observed when compared to control as measured by aggregation responses to adenosine diphosphate (ADP), collagen and ristocetin, hypotonic shock response and pH during 5 d of storage. Lactate levels were significantly higher (P less than 0.01) and glucose levels lower (P less than 0.01) in UV-treated PC, although in the majority the lactate level did not exceed 20 mmol/l. Betathromboglobulin and platelet factor 4 levels were higher during storage in the UV group, the latter reaching significance (P less than 0.05). When whole platelets and platelet membranes were stained with Coomassie blue or Periodic Acid-Schiff's reagent after electrophoresis in polyacrylamide gels no obvious alterations to major membrane constituents were observed on days 1 and 5 of storage. Paired in vivo autologous studies in healthy volunteers using 111Indium-labelling were performed at the end of 5 d of storage. The UV-treated platelets gave satisfactory and equivalent results for recovery, half life and survival when compared to controls. We conclude that PC irradiated with UVL and stored for 5 d in DuPont Stericell containers appear suitable for transfusion and may prove to be nonimmunogenic. Further in vivo studies of haemostatic efficacy and recipient alloimmunization are now warranted.

Blood Platelets↗
PubMed1984

Two individuals with elliptocytic red cells apparently lack three minor erythrocyte membrane sialoglycoproteins.

We have studied the erythrocytes of two individuals (P. L. and K. W.) who lack the Gerbich (Ge) blood-group antigen. The erythrocytes of P. L. and K. W. were not reactive with two monoclonal antibodies (NBTS/BRIC 4 and NBTS/BRIC 10) which reacted with normal erythrocytes. The membranes of P. L. and K. W. erythrocytes appeared to lack three minor sialoglycoproteins (beta, beta 1 and gamma). These three minor sialoglycoproteins were found to be associated with the cytoskeletons of normal erythrocytes. Approx. 10% of the erythrocytes of P. L. and K. W. were frankly elliptocytic. We suggest that one or more of the minor sialoglycoproteins may play a part in maintaining the discoid shape of the human erythrocyte.

Blood Group Antigens↗
PubMed1983

Effect of new plastics and leucocyte contamination on in vitro storage of platelet concentrates.

Platelet concentrates were prepared for in vitro storage in either Fenwal PL-732 or Cutter CLX platelet packs. The units were stored at 22 degrees C for seven days with either horizontal or tumbler agitation. Measurement of pH, hypotonic shock response and serotonin uptake indicated in vitro viability was well maintained during 5-7 days storage using either type of pack with either mode of agitation. The longer storage interval did not effect either plasma fibrinogen concentrations or binding of monoclonal antibody, AN51. However, gross contamination of the units with leucocytes caused increased glucose consumption, substantial fall in pH and loss of in vitro viability after five days storage. The work suggests the shelf-life of platelet concentrates can be extended to five days and that they are clinically effective providing the leucocyte contamination is minimised.

Blood Glucose↗
PubMed1981

Longitudinal muscle of muscularis externa in human and nonhuman primate colon.

The idea that the longitudinal muscle of the muscularis externa of the colon is confined to the colonic teniae in the monkey and human is a common conceptual error. Forty-six colon specimens taken from human and nonhuman primates were reviewed histologically and the distribution and structure of the longitudinal muscle were evaluated. We found that the longitudinal muscle forms a complete coat around the colon although it is considerably thicker in the region of the teniae coli. In addition to its anatomic importance, this observation has implications for the physiology of colon muscle and for certain current hypotheses concerning the etiology of diverticulitis.

Animals↗
PubMed1981

A device to stimulate the mechanical component of malignant bowel obstruction.

A predictable and progressive experimental intestinal obstruction, simulating a malignancy but without neoplastic change has been produced by application of a silicone rubber ring around the bowel of 20 rats, seven dogs, and five monkeys. Serosal reaction produced fibrous tissue that resulted in an "apple core" obstruction. An easily assembled extraluminal balloon device of silicone rubber can be used to produce acute and progressive experimental obstruction, especially of the large bowel.

Acute Disease↗
PubMed1980

Intestinal motility changes in experimental large bowel obstruction.

Bipolar electrodes for recording electrical discharges of colon smooth muscle and strain gages for recording associated contractions of circular muscle were implanted in six rhesus monkeys. After recovery, baseline records were made. The animals then had an obstruction device implanted in sigmoid colon which resulted in progressive compromise of the lumen terminating in complete obstruction after 13 +/- 2 days. Recording were made daily during development of obstruction. As obstruction became more complete, contraction frequency decreased in right colon, increased in left colon proximal to the obstruction, and was unchanged in left colon distal to the obstruction. The frequency of distentions increased in colon proximal to the obstruction but was unchanged distally. Simultaneous mass actions, a complex of nonperistaltic high amplitude contractions and distentions occurring nearly simultaneously throughout the colon which is not seen in normal colon, appeared in colon both proximal and distal to the obstruction and became more frequent as the degree of obstruction progressed. Colon obstruction results in abnormal motility complexes, but not in hyperperistalsis. Mass actions probably are the basis for colic and rushing bowel sounds noted clinically in colon obstruction.

Action Potentials↗
PubMed1979

Evidence for a therapeutic effect of plasmapheresis in patients with systemic lupus erythematosus.

Fourteen patients with active systemic lupus erythematosus (SLE) have been treated with plasmapheresis at a rate of two litres daily on three to four days per week, over a period of two to three weeks. Plasma was replaced isovolemically with either fresh frozen plasma or with human plasma protein fractions. Ten patients were receiving treatment with prednisone at the time of plasmapheresis, and four had received no prior treatment. Eight patients showed evidence of either clinical improvement or clinical and immunochemical improvement, at the time of plasmapheresis. In the three patients who showed high levels of circulating complexes before treatment, there was a sudden fall in the level of circulating immune complexes, which was quantitatively greater than could be explained by the amount removed. This suggests that in some patients with SLE, clearance of complexes by the mononuclear phagocytic system is initially blocked by high levels of circulating complexes and that one effect of plasmapheresis may be to relieve this blockade. Five patients showed a clinical response to plasmapheresis despite the fact that tests for immune complexes were negative. Three patients showed no response to plasmapheresis, and three were regarded as unevaluable. In a limited number of patients, who show a high level of circulating immune complexes, and whose condition is deteriorating despite treatment with corticosteroids, there may be an important therapeutic role for plasmapheresis.

Adolescent↗
PubMed1976

Intensive antenatal plasmapheresis in severe rhesus isoimmunisation.

Intensive antenatal plasmapheresis can significantly lower Rh-antibody levels in the blood of mothers carrying babies severely affected with rhesus haemolytic disease. Twenty-seven out of forty-four mothers were successfully delivered of babies that survived, after being treated with a combination of plasmapheresis and intrauterine transfusions. A further 52 mothers were treated by plasmapheresis along. When severe disease developed as an early stage in pregnancy the results were rather poor, but excellent results were obtained when severe disease developed relatively late in pregnancy. No serious complications were encountered in the mothers or babies.

Blood Transfusion, Intrauterine↗
PubMed1976

Lymphocyte response to blood transfusion in man: a comparison of different preparations of blood.

The appearance of atypical lymphocytes in post-transfusion blood, their incorporation of tritiated thymidine in tissue culture and the elimination of cytotoxic antibody production, have been used as markers to show that frozen red cells are the least immunogenic when compared with dextran sedimented blood and whole blood donations. The absence of atypical lymphocytes and failure to produce lymphocytotoxic antibodies after transfusion of frozen cells is highly significant (P is less than 0.001) when compared with whole blood donations.

Antibodies, Viral↗
PubMed1975

Spontaneous rupture of the pharynx.

A case of spontaneous rupture of the pharynx is described occurring during the act of vomiting. Comparisons are made with the only known previously recorded case of spontaneous pharyngeal rupture.

Aged↗