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Biomedical subjects

R McCabe

Publications and source records attributed to R McCabe.

At least 37 records · Page 2Linked to original sources

Zinc supplementation during pregnancy: a double blind randomised controlled trial.

OBJECTIVE: To see whether zinc supplementation during pregnancy improves maternal and fetal outcome. DESIGN: Prospective study started at booking and continued till discharge of mother and baby from the maternity hospital. Mothers were randomly assigned to receive zinc supplementation or placebo in a double blind trial. SETTING: Mothers booking at one hospital. PATIENTS: Women booking before 20 weeks of gestation who agreed to take part in the study. 494 Mothers were followed up till the end of pregnancy. There was no difference between the groups given zinc and placebo in their social or medical backgrounds. INTERVENTIONS: Mothers in the active treatment group received one capsule of 20 mg elemental zinc daily and those in the placebo treated group a capsule identical in appearance and taste with the active capsule but which contained inert substances. MAIN OUTCOME MEASURE: Various adverse outcomes were tested, including maternal bleeding, hypertension, complications of labour and delivery, gestational age, Apgar scores, and neonatal abnormalities. The main outcome measure was birth weight. RESULTS: There were no differences whatsoever between mothers given a zinc supplement and those given a placebo. CONCLUSION: Zinc supplementation in pregnancy in the United Kingdom does not seem to offer any benefits to the mother or her fetus.

Adult

Recurrent IgA nephropathy in living-related donor transplantation: recurrence or transmission of familial disease?

We describe a patient who developed terminal renal failure of two HLA-identical renal allografts due to crescentic IgA nephropathy. The first graft contained IgA deposits at the time of donation, suggesting that transmission of IgA deposits may have contributed to the nephritis of the first allograft. The second graft was free of IgA deposits at the time of donation, but the recipient developed a similar, rapidly progressive nephritis. This case points up the malignant potential of IgA nephropathy and the complex nature of transplant planning for patients with end-stage renal disease (ESRD) secondary to IgA nephropathy. Living-related donor (LRD) transplants seem to be associated with a higher rate of recurrence than cadaveric grafts. This higher rate may partly reflect the inadvertent transmission of subclinical IgA deposits from donor to recipient and a genetic susceptibility of certain HLA types (specifically B35 and DR4) to recurrent disease. Cadaveric transplants may be preferable in the setting of high-risk HLA types or familial patterns of IgA nephropathy.

Adult

Nifedipine and platelets in preeclampsia.

In addition to its antihypertensive properties, nifedipine inhibits platelet aggregation in vitro. Because increased platelet aggregation is a feature of preeclampsia, we have investigated nifedipine in this condition. Ten women at 31 +/- 2.8 weeks gestation, with blood pressure 162 +/- 18/102 +/- 10 mmHg (despite atenolol 200 mg/day) and proteinuria 2.0 +/- 1.1 g/24 hr, were treated with nifedipine. Pregnancies were prolonged by 17 +/- 15 days (range 5 to 56). Blood pressure was controlled in eight of the ten patients, final values before delivery being 142 +/- 16/89 +/- 12 mmHg (P less than 0.02). Platelet count rose in all women from 190 +/- 80 to 261 +/- 78 X 10(9)/1 (P less than 0.001). Nifedipine appears to reverse the thrombocytopenia of pre-eclampsia, in addition to controlling the blood pressure.

Blood Pressure

Carumonam versus ceftazidime for urinary tract infections.

Carumonam is a new monobactam antibiotic with potent activity against gram-negative aerobes. To study the efficacy and safety of carumonam for treatment of complicated and uncomplicated urinary tract infections, 54 patients were randomized to therapy with either carumonam or ceftazidime. Of 42 patients who could be evaluated, 82% of the carumonam-treated patients and 80% of the ceftazidime-treated patients were cured clinically. At 5 to 9 days posttherapy, microbiologic criteria indicated that 13 carumonam-treated patients (48%) and 8 ceftazidime-treated patients (53%) were cured. Patients with indwelling bladder catheters at the end of therapy had a markedly worse microbiologic outcome than those without catheters. Enterococcus sp. reinfection was common in both groups. Possible adverse clinical and laboratory reactions occurred in six carumonam-treated patients (21%) and four ceftazidime-treated patients (27%). Most reactions occurred at the end of therapy and resolved with discontinuation of the study drug. In this small study, carumonam appeared as safe and as effective as ceftazidime for the treatment of complicated and uncomplicated urinary tract infections.

Adult

Effect of antiidiotypic antibodies to HLA on graft survival in renal-allograft recipients.

Although the presence in the recipient of preformed antibodies to HLA antigens in the kidney of a renal-transplant donor may be associated with early graft failure, such grafts are often well tolerated. We have investigated the possibility that anti-anti-HLA (antiidiotypic) antibodies influence the outcome of renal transplantation in recipients with a history of presensitization to their donor's HLA antigens. A retrospective analysis of 20 such cases showed that in 10 patients the transplanted kidney was rejected within one month, whereas in the remaining 10 the graft was tolerated for more than a year. Nine of the 10 patients in whom the graft was tolerated had anti-anti-HLA antibodies at the time of transplantation. Nine of the 10 patients in whom the graft was rejected had antibodies that potentiated, rather than blocked, the cytotoxic activity of anti-donor-HLA antibodies. These results suggest that patients with anti-anti-HLA antibodies specific for a potential donor can safely undergo transplantation, despite a prior history of anti-HLA antibodies. At the time of transplantation, patients who have antibodies that potentiate the cytotoxic activity of a historically positive serum are at high risk of graft rejection within a short period. Taking these considerations into account may improve the reliability of cross-matching in renal transplantation.

Antibodies, Anti-Idiotypic

The influence of pregnancy on drug action: concentration-effect modelling with propranolol.

The physiological changes of pregnancy have been shown to alter the disposition of some drugs. However, there are no data on the possible influence of pregnancy or its complications on drug effect. We have applied drug concentration-effect analysis to determine whether pregnancy influences the action of propranolol. Twelve women with pregnancy induced hypertension were studied during the third trimester and again 2-3 months post partum. On each occasion propranolol (10 mg) was given intravenously and measurements of heart rate, blood pressure and whole blood propranolol concentration were determined over the ensuing 8 h. Pregnancy did not alter propranolol disposition. Clearance was 0.63 +/- 0.18 and 0.71 +/- 0.24 litre h-1 kg-1, and volume of distribution at steady state was 4.02 +/- 2.98 and 3.07 +/- 1.58 litres/kg during and after pregnancy respectively. There was no fall in blood pressure over the period of the acute study. The reduction in heart rate (beats/min per ng of propranolol/ml) was greater during compared with after pregnancy: -0.61 +/- 0.23 and -0.39 +/- 0.19 respectively (F = 6.64; df 1.9; P less than 0.03). There was no relationship between blood pressure or pretreatment heart rate and the slope of the concentration-effect relationship. We conclude that pregnancy can significantly alter drug effect in the absence of any pharmacokinetic changes. These findings suggest that therapeutic ranges established in non-pregnant patients may not be applicable during pregnancy.

Adult

Plasma catecholamines in pregnancy induced hypertension.

Increased activity of the sympathetic nervous system has been implicated in the genesis of early hypertension in young people. Studies in pregnancy allow observations to be made on evolving, recently established and resolving hypertension in the human. We describe the results of two studies involving women who developed hypertension during pregnancy. In the first study, plasma concentrations of noradrenaline and adrenaline were measured in 17 women with pregnancy induced hypertension (PIH) and 17 normotensive pregnant control subjects. Plasma noradrenaline (nmol/l) was lower in the PIH group compared with control patients in both semi-recumbent (1.11 +/- 0.53 vs 1.98 +/- 0.96, P less than 0.001) and standing positions (1.31 +/- 0.65 vs 2.57 +/- 1.27, P less than 0.005). Five days post partum, plasma noradrenaline had risen in the PIH group compared with pregnant values in semi-recumbent (1.65 +/- 1.0 vs 1.11 +/- 0.52, P less than 0.05) and standing positions (2.46 +/- 1.5 vs 1.31 +/- 0.65, P less than 0.05). In the normotensive patients plasma noradrenaline did not differ between post partum and pregnant values (1.51 +/- 0.73 vs 1.98 +/- 0.96 semi-recumbent; 2.00 +/- 1.16 vs 2.57 +/- 1.7 standing). Logarithmic transformation of the noradrenaline concentration data resulted in a significant (P less than 0.02) negative correlation with diastolic blood pressure in the pregnant patients but not post partum. Plasma adrenaline concentration was the same in both groups. In the second study, plasma concentrations of noradrenaline and adrenaline were measured sequentially through pregnancy in five women who developed PIH and five control subjects who remained normotensive.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Maternal and fetal platelet responses and adrenoceptor binding characteristics.

Paired blood samples were obtained from mothers (venous) and babies (cord venous blood) at the time of delivery by caesarean section under epidural anaesthetic. Fetal platelets failed to aggregate in response to adrenaline in vitro although adrenaline could potentiate the threshold response to adenosine diphosphate (1 microM). Fetal platelet responses to collagen and 8 Arg vasopressin did not differ significantly from maternal responses. Maternal and fetal platelets also showed similar inhibition of aggregation after activation of adenylate cyclase (PGE1 and parathormone), in contrast to the inhibition of adenylate cyclase by adrenaline. Alpha 2 adrenoceptors were investigated using [3H] yohimbine binding receptor number and were reduced modestly but significantly on fetal compared to maternal platelets. The failure of fetal platelet aggregation in response to adrenaline appears to be related to a failure of receptor coupling and may represent a delayed maturation of fetal platelet alpha receptors or a response to increased circulating catecholamines during birth.

Adenosine Diphosphate