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Biomedical subjects

A R Wilkinson

Publications and source records attributed to A R Wilkinson.

At least 109 records · Page 6Linked to original sources
PubMed1980

Indium (111In)-labelled human platelets: optimal method.

1. A detailed laboratory method is described for the labelling of human platelets with [111In]indium oxine. The 45 min method is simple, requires on 26 ml of blood and is suitable for routine clinical use. 2. After the labelling and resuspension of the platelets in plasma, aggregation responses to both adenosine diphosphate and collagen were similar to those of normal platelet-rich plasma. Less than 5% of the [111In]indium oxine was released by secretory function of platelets. 3. Labelling efficiencies of 90.1 +/- 4.29% (n = 28) were achieved in 60 s by normal concentrations of plasma-free platelet suspensions. 4. Platelet survival in vivo in healthy volunteer subjects follows a linear function with a survival time of 8.44 +/- 0.18 days.

Blood Platelets↗
PubMed1980

In vivo oxygen dissociation curves in transfused and untransfused newborns with cardiopulmonary disease.

We used a new, rapidly responding in vivo catheter oximeter to continuously measure arterial oxygen saturation (Sao2) in 34 newborns with cardiopulmonary disease. The Sao2 was compared with the oxygen tension (Pao2) of blood sampled through the catheter in 2 groups. We evaluated the oxygen dissociation curves of 24 untransfused infants whose hemoglobin F (HbF) concentration was greater than or equal to 80%. We also examined the Sao2 curves of 20 extensively transfused infants who had greater than or equal to 80% hemoglobin A (HbA). We found a wide variation in Sao2 at levels of arterial Po2 between 30 and 90 mmHg. Although the oxygen dissociation curve of the transfused group was significantly to the right of the untransfused group, there was considerable overlapping between the 2 curves. This dispersion reflected the wide range of clinical states encountered in newborns with cardiopulmonary disease, and the changes in blood oxygen affinity. In some newborns, when Pao2 was less than 50 mmHg, Sao2 could be > 90% whereas in others, Sao2 could be < 75%. When both Pao2 and Sao2 were low, Sao2 reflected arterial oxygen contents more precisely because of the shape of the individual oxygen dissociation curves in both groups. Opinions vary as to the safe upper limit of Pao2 at which retrolental fibroplasia does not occur. The Sao2 at 2 upper limits of Pao2 (100 and 80 mmHg) was estimated by probit analysis of simultaneous measurements of Pao2 and in vivo Sao2. In both the untransfused and extensively transfused groups of newborns, Pao2 was < 100 mmHg when Sao2 was < 96%. The Pao2 was < 80 mmHg, when the Sao2 was < 92%, if the HbF was greater than equal to 80%, and when Sao2 was < 91%, if HbA was greater than equal to 80%, (95% confidence limits). The findings suggested a caveat against the practice of calculating Sao2 from measurements of pH, Pao2, and Paco2. This can be quite inaccurate when taking samples of arterial blood from newborns.

Blood Transfusion↗
PubMed1979

Continuous in vivo oxygen saturation in newborn infants with pulmonary disease: a new fiberoptic catheter oximeter.

We measured the in vivo oxygen saturation of hemoglobin in the arterial blood of 34 sick newborn infants with a new, rapidly responding, continuously recording, catheter oximeter. The oxygen saturation, SaO2, was found to fluctuate between 85 and 95% in infants with pulmonary disease who are in a stable condition and breathing spontaneously. Severe disaturation occurred during apnea and after procedures such as chest percussion and suctioning of the endotrachael tube. The effects of changes in respiratory therapy were quickly manifested by changes in SaO2. This was particularly useful in guiding resuscitation of newborn infants who were asphyxiated at birth. Blood sampling for measurement of PaO2 can be done less frequently, reducing the need for blood transfusions in small infants.

Apnea↗
PubMed1979

Persistent pulmonary hypertension and abnormal prostaglandin E levels in preterm infants after maternal treatment with naproxen.

Twins and a singleton were born at 30 weeks' gestation although naproxen (d-2 (6'methoxy-2-naphthyl) propionic acid) had been given to the mothers in an attempt to delay parturition. Inhibition of prostaglandin synthesis was shown by very low plasma concentrations of prostaglandin E and the ductus arteriosus remained closed despite signs of pulmonary hypertension with severe hypoxaemia. Abnormalities in blood clotting, renal function, and bilirubin metabolism were also found and one infant died. Further studies of the benefits and risks of the inhibition of prostaglandin synthesis are required before this treatment of preterm labour is accepted.

Adult↗
PubMed1979

Continuous transcutaneous and intraarterial oxygen measurement during experimental hypoxemia in infant monkeys.

The relationship between PaO2 and tcPO2 is an important one and provides a physiologic measure of impaired circulatory control or vascular damage. The central and peripheral mechanisms involved have to be studied further. Although tcPO2 equates well with PaO2 in many circumstances, appropriate oxygen conserving, centrally mediated vasoconstriction can overcome the thermally induced local vasodilation. Investigation of the control of peripheral circulation in both clinical medicine and the experimental animal is advanced by the technique of transcutaneous oxygen recording.

Animals↗
PubMed1977

Prophylactic use of cephazolin against wound sepsis after cholecystectomy.

A trial of antibiotic prophylaxis with cephazolin against postoperative wound sepsis was carried out on 201 patients undergoing routine cholecystectomy. Wound sepsis occurred in 11 out of 65 controls (16.9%), who were not given the drug; two out of 63 patients (3.2%) given a single dose preoperatively; and four out of 73 patients (5.5%) given the single preoperative dose plus a five-day course postoperatively. The difference between the controls and patients given the single preoperative dose was significant.

Cefazolin↗
PubMed1976

Fibrin subunits in venous and arterial thromboembolism.

The subunit fibrin composition of thrombi of both venous and arterial origin was examined by sodium dodecyl sulphate gel electrophoresis. The thrombi were recovered by surgical intervention and all had the same fibrin subunit composition. The alpha chains were cross-linked as alpha-chain polymers alpha (p), the gamma chains as gamma-chain dimers (gamma-gamma) while the beta chains were not crosslinked; a further subunit of molecular weight 33 000 was shown to be present in all the fibrins examined and was a degradation fragment of the beta or gamma chains. This data suggests that the crosslinked alpha chains are rate limiting to the lysis of thrombi in vivo. The digestion of pulmonary emboli by plasmin yielded soluble degradation products which were identified as D dimer and E, the latter fragments being the major products obtained by the lysis of in-vitro made plasma clots. The similarity of the composition and lysis of thrombus fibrin to that formed in vitro augurs well for the justification of in-vitro research on mechanisms in thrombolysis.

Electrophoresis, Polyacrylamide Gel↗
PubMed1975

Frusemide in respiratory distress syndrome.

Savage, M. O., Wilkinson, A. R., Baum, J. D., Roberton, N. R. C. (1975). Archives of Disease in Childhood, 50, 709. Frusemide in respiratory distress syndrome. The effect of frusemide on urinary volume, urinary sodium excretion, and urinary calcium excretion in 7 premature infants with severe respiratory distress syndrome (RDS) has been studied. The results are compared with similar measurements on 13 infants of comparable gestational age and birthweight with less severe RDS who did not receive frusemide. The effect of frusemide on PaO2 and PaCO2 tensions in 5 infants with RDS was also investigated. Frusemide produced a fourfold increase in urinary volume and a tenfold increase in urinary sodium and urinary calcium excretion compared with the untreated group. It caused no improvement in blood gas tensions. The use of this diuretic for the routine management of RDS cannot be recommended.

Calcium↗