Biomedical subjects

A F Penny

Publications and source records attributed to A F Penny.

5 recordsLinked to original sources

PubMed1988

Reactivation of creatine kinase activity by preincubation with buffered NAC diluent.

We have shown that several commercial control sera containing reversibly inactivated creatine kinase are reactivated by pre-incubation in N-acetyl cysteine assay diluent. The increase in activity can proceed for up to 4 h. This reactivation is not seen in patients' sera even after storage for 14 days at -20 degrees C, 7 days at 4 degrees C, or 2 days at 20 degrees C, during which time no loss of activity was evident. This study brings into question the validity of using consensus values to standardise enzyme assays.

Acetylcysteine↗

PubMed1983

Pilot study for large-scale plasma procurement using automated plasmapheresis.

A pilot study for large-scale automated plasmapheresis using the Haemonetics Model 50 machine was undertaken in the Yorkshire Region of the United Kingdom to determine the viability of such a programme for national self-sufficiency in fresh plasma procurement for factor VIII concentrate production. The study was designed to resolve three areas of concern: donor safety and recruitment; a cost analysis, and the choice of anticoagulant for optimum factor VIII yields. The results show that large-scale automated plasmapheresis could safely and economically produce high-quality source plasma necessary for national self-sufficiency.

Anticoagulants↗

PubMed1980

Citrate induced hypocalcaemia during cell separation.

The value of calcium addition during cell-separation by the Haemonetics Model 30 has been investigated in two patient groups. Where citrated plasma was used as the replacement fluid the addition of calcium abolished clinical symptoms and reduced the degree of citrate induced hypocalcaemia. When Plasma Protein Fraction was used as the replacement fluid, calcium addition was not necessary as clinical symptoms and significant hypocalcaemia did not occur.

Calcium↗

PubMed1979

The interaction of varying doses of dipyridamole and acetyl salicylic acid on the inhibition of platelet functions and their effect on bleeding time.

1 In normal volunteers maximum reductions in platelet functions, collagen aggregation, adhesion and PF4 availability, were achieved using combined doses of 50 mg three times daily dipyridamole + 180 mg ASA or 75 mg three times daily dipyridamole + 120 mg ASA daily. 2 These doses did not prolong the bleeding time. 3 A synergistic effect has been demonstrated with 25 mg dipyridamole three times daily and 60 mg ASA. 4 At higher doses the effects on platelet functions were additive up to the maximal response. 5 The effect of low doses of ASA on platelet function was cumulative. 6 As lower doses of ASA in the combination studied inhibit platelet functions maximally without altering the bleeding time and probably without inhibiting prostacyclin, we suggest that these combinations of dipyridamole and ASA merit consideration in future clinical trials.

Adult↗

PubMed1977

The effect of dipyridamole on platelet function: correlation with blood levels in man.

1 The effect on platelet functions of dipyridamole (a pyrimido-pyrimidine compound) was compared with a control group of patients taking warfarin. 2 Adhesion, aggregation and platelet factor 4 availability showed a significant decrease in the dypyridamole group. 3 Aggregation and platelet factor 4 showed a significant correlation with blood dipyridamole level. 4 Adhesion, aggregation and platelet factor 4 were reduced below the lower limit of normal at blood dipyridamole levels above 3.5 micronmol/1.

Blood Platelets↗