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Biomedical subjects

D MacDonald

Publications and source records attributed to D MacDonald.

At least 37 records · Page 2Linked to original sources
PubMed1990

The effect of hyperthyroidism on in vivo aging of erythrocyte ouabain-binding sites and intracellular sodium and potassium.

The sodium pump activity of erythrocytes is inhibited in hyperthyroidism, whereas in all other cells it is increased. To examine the possibility that thyroid hormones cause an accelerated loss of membrane proteins during in vivo aging, we determined the number of ouabain-binding sites (OBS) in young and old erythrocytes from 13 hyperthyroid and 13 euthyroid subjects. Erythrocytes were separated according to their cell age by centrifugation. In euthyroid subjects, the median number of OBS decreased from 415 (range, 341-551; mean +/- SEM, 440 +/- 19.1) in young cells to 336 (range, 287-453; mean, 340 +/- 13.6) in old cells. In hyperthyroid subjects the median number of OBS decreased from 290 (range, 190-370; mean, 280 +/- 13.3) in young cells to 207 (range, 155-244; mean, 208 +/- 7.5) in old cells. In hyperthyroid subjects the number of OBS of erythrocytes of all ages was lower than that in euthyroid subjects. The ratio of OBS between young and old cells in hyperthyroid subjects (median, 1.27; mean +/- SD, 1.34 +/- 0.16) was similar to that in euthyroid subjects (median, 1.29; mean, 1.30 +/- 0.12). We conclude that these results do not support the hypothesis that in hyperthyroidism there is accelerated loss of sodium pump sites during the lifespan of erythrocytes in circulation.

Adult↗
PubMed1990

Adult respiratory distress syndrome due to blastomycosis during pregnancy.

A 23-year-old healthy woman in her third trimester of pregnancy developed adult respiratory distress syndrome secondary to Blastomyces dermatitides. Pregnancy-related immunosuppression was believed to be responsible for the fungal infection. Following emergency delivery of the infant and a full course of amphotericin B therapy, the patient made an uneventful recovery. Although the fetal and maternal sides of the placenta demonstrated fungal spores, the child remained healthy. To our knowledge, this is the first report of blastomycosis-associated adult respiratory distress syndrome occurring during pregnancy.

Adult↗
PubMed1990

The influence of birth weight on labor in nulliparas.

The purpose of this study was to examine the hypothesis that dystocia in nulliparas is directly related to birth weight. The study was confined to the first 1000 nulliparas delivered in 1988 who went into labor after 37 weeks' gestation with a single live fetus and cephalic presentation. The management of labor was standardized. As birth weight increased, there was an increase in the mean duration of labor and of the second stage of labor, in the incidence of oxytocin augmentation, and in the incidence of both cesarean and forceps delivery for dystocia. The direct relationship between birth weight and the mean duration of labor was independent of gestation and oxytocin augmentation. These findings suggest that birth weight is an important factor in the development of dystocia in nulliparas.

Birth Weight↗
PubMed1989

Cerebral palsy among children born during the Dublin randomised trial of intrapartum monitoring.

In a randomised trial involving 13,079 liveborn children intrapartum care by electronic fetal heart rate monitoring, with scalp blood sampling when indicated, was associated with a 55% reduction in neonatal seizures. Reassessment, when aged 4, of the 9 children in the intensively monitored group and 21 in the control group who survived after neonatal seizures showed that 3 such children in each group had cerebral palsy. A fourth child in the intensively monitored group with cerebral palsy had had transient abnormal neurological signs during the neonatal period. 8 other children in the intensively monitored group and 7 in the control group who had not had abnormal neurological signs in the neonatal period also had cerebral palsy. 16 (78%) of the total of 22 cases of cerebral palsy had not shown clinical signs suggestive of intrapartum asphyxia. Thus, compared with intermittent intrapartum monitoring, intensive monitoring has little, if any, protective effect against cerebral palsy.

Asphyxia Neonatorum↗
PubMed1989

Acid-etch rethink.

Explore the source record for details and available documents.

Acid Etching, Dental↗
PubMed1989

Successful outcome after antepartum expulsion of placenta and fetus into the abdominal cavity; a case report.

Spontaneous rupture of the uterus before labour is a rare event associated with a high incidence of maternal and fetal death. We report a case of spontaneous uterine rupture at 34 weeks' gestation in a patient's second pregnancy. The case is unusual because both the mother and baby survived despite the expulsion of the placenta with the fetus into the abdominal cavity prior to laparotomy.

Abdomen↗
PubMed1989

The unique N-terminal domain of the large subunit of herpes simplex virus ribonucleotide reductase is preferentially sensitive to proteolysis.

Using antisera made against peptides corresponding to different regions of the large subunit of herpes simplex virus type 1 ribonucleotide reductase we have probed proteolytic fragments of this protein and found that at least a part of its unique N-terminal domain is not necessary for enzyme activity. This non-essential region encompasses the domain previously predicted to be composed of beta sheets with a well buried core of hydrophobic residues. Truncated forms of the large subunit are generated in vivo and are located almost exclusively in the nucleus.

Amino Acid Sequence↗
PubMed1989

A comparison of the acute-phase response in middle aged and elderly patients.

The acute phase response in middle aged and elderly patients was compared by measuring the ratio of the peak C-reactive protein to peak creatine kinase level during the three day period after acute myocardial infarction. No difference in ratio was observed between a middle aged group of 14 patients (10.2 +/- 4.0 mean +/- s.e.), and an elderly group of 13 patients (9.1 +/- 1.5). C-reactive protein levels in two groups of middle aged and elderly control patients were similar (10.1 +/- 0.04 mg/l and 11.8 +/- 0.10 mg/l respectively). Production of C-reactive protein does not appear to be impaired in the elderly.

Acute-Phase Reaction↗
PubMed1989

Plasma 25-hydroxyvitamin D concentration in patients with hip fracture in Hong Kong.

The serum concentration of 25-hydroxyvitamin D level and plasma albumin-adjusted calcium, phosphate, and alkaline phosphatase levels were studied in 200 patients with hip fracture (age range 49-93 years) and 427 elderly subjects living in the community (age range 60-90 years). The mean serum 25-hydroxyvitamin D levels in controls were higher than in temperate countries, but the 25-hydroxyvitamin D concentration was significantly lower in the patients than the controls for all sex and age groups. There was little difference in albumin-adjusted calcium and alkaline phosphatase levels, but the phosphate level was higher in the patients than in the controls. None of the patients with a low 25-hydroxyvitamin D level had a blood picture suggestive of osteopathy resulting from vitamin D deficiency or frank osteomalacia. Hip fracture patients with a low 25-hydroxyvitamin D level were much less ambulant and went outdoors much less frequently than hip fracture patients with a normal vitamin D level. A low vitamin D level was a risk factor for hip fracture in Hong Kong Chinese, and may be prevented by frequent outdoor exposure.

Aged↗
PubMed1989

Organized personal care--an effective choice for managing diabetes in general practice.

A system of diabetic review was introduced in two Southampton training practices in March 1985. Each partner, with the help of the practice nurse, retained responsibility for review of their own diabetic patients. During the study period (1984-86) 213 diabetics remained with the practices. In 1984 there were 94 non-insulin dependent patients who were not receiving hospital outpatient care. Over the study period there was an increase in the surveillance of blood glucose, blood pressure, weight, urine (for protein), fundi, visual acuity and feet for this group so that in 1986 between 79% and 89% of patients were having these parameters checked at least annually. More complications were found and more referrals for specialist evaluation were made. There was a trend towards transfer of care from the hospital to the general practitioner, and the proportion of non-insulin dependent diabetic patients receiving their care entirely from general practice increased from 22% to 60% over the period. There was a small increase in the workload of the general practitioners and a considerable contribution to care was made by the practice nurses. It is concluded that structured personal diabetic care based on a nurse coordinated service is a satisfactory alternative to the 'specialist' general practitioner mini-clinic model.

Aged↗
PubMed1989

Some biochemical indices of bone turnover in elderly Chinese.

Biochemical indices of bone turnover were determined in a cluster sample of 427 apparently healthy elderly subjects aged 60 years and over. Plasma calcium concentrations corrected for albumin were not significantly different between elderly men and women, but were higher compared with values in younger Chinese of the same sex. The prevalence of hypercalcemia (greater than 2.75 mmol/L) in the elderly (0.2%) was lower than in Caucasian populations. Plasma phosphate concentrations were higher in women, but lower than in young adults. Plasma alkaline phosphatase activity was higher in women compared with values for men, and higher compared with values for young adults. Plasma 25-hydroxyvitamin D was lower in elderly women than elderly men, but was similar to values in younger subjects. Urinary calcium: creatinine and hydroxyproline: creatinine ratios were higher in women. The values were comparable to those for Caucasian postmenopausal women, suggesting that Chinese elderly subjects had similar bone turnover rates.

Adult↗
PubMed1988

Isolation of a DNA fragment which complements glutamine synthetase deficient strains of S. pombe.

From a gene bank of S. pombe DNA, a 5.6 kb clone was isolated which complemented mutants defective in glutamine synthetase (GS) activity. Sub-cloning fragments of this 5.6 kb clone showed that the complementing activity was localised in a 1.6 kb HindIII-AvaI fragment and a partial DNA sequence revealed an open reading frame preceded by TATA sequences and a TGACTA sequence. Plasmid constructs carrying up to 3.4 kb of DNA used to transform gln- strains gave transformants which showed a wide range of GS activity, in some cases 100 times the wild-type level. These constructs identify DNA sequences lying downstream from the putative coding sequence which have effects on the total amount of enzyme activity, but do not affect the control imposed by the nitrogen source on which the cells are grown.

Amino Acid Sequence↗
PubMed1988

Q fever following bone marrow transplantation.

We describe a patient who developed an acute febrile illness 85 days after receiving an allogeneic bone marrow transplant for acute myeloid leukaemia. Serological investigation indicated the cause to be Q fever. The patient was receiving concurrent immunosuppressive therapy for graft-versus-host disease (GVHD). Coxiella burnetii should be added to the list of organisms which may complicate bone marrow transplantation. This case also provides further evidence to support an association between immunocompromised conditions and the development of Q fever.

Adult↗
PubMed1988

Bone marrow transplantation for adults and children with poor risk acute lymphoblastic leukaemia in first complete remission.

Thirty-two patients with poor risk acute lymphoblastic leukaemia in first complete remission received bone marrow transplants (BMT) from fully matched family donors. Their ages ranged from 7 to 41 (median 23) years. Nine patients were aged 16 years or less. Patients were selected for BMT because they had risk factors for relapse with standard treatment approaches. In particular the children who were selected for BMT had presenting blast counts of greater than or equal to 90 x 10(9)/l or null immunophenotypes. The overall disease-free survival was 50% with a relapse risk of 31% at 9 years. Patients aged less than 16 years had a much lower risk of both graft-related disease and relapse than did older patients (disease-free survival 89% for those aged 7-16, 48% for those aged 17-26, 24% for those aged 26-41). We conclude that selection of BMT for young patients with poor risk features is entirely justified but that the prognosis for older patients is poor even after BMT.

Adolescent↗
PubMed1987

Differences in erythrocyte cation (sodium) transport between Chinese and non Chinese males.

Erythrocyte sodium content, sodium pump activity (ouabain sensitive efflux rate, efflux rate constant, ouabain binding sites and Na+, K+-ATPase activity), sodium-lithium countertransport and sodium-potassium cotransport activities were measured in 10 European males, 11 non Chinese Asian males and 12 Chinese males. There were no differences between the 3 groups in any of the measurements of active transport. The sodium-lithium countertransport was higher and sodium-potassium cotransport (measured as lithium-potassium cotransport) was lower in Chinese compared to either the Europeans or non Chinese Asians. There were no differences in counter and cotransport activities between the Europeans and non Chinese Asians. Multiple regression analysis showed that the co and countertransport pathways contribute little to the maintenance of erythrocyte sodium content in healthy subjects.

Adult↗
PubMed1986

Effects of drug and alcohol abuse upon pituitary-testicular function in adolescent males.

To assess the effects of drug and alcohol abuse (DAA) on the physical changes and hormones of puberty in adolescents, 26 males (13 5/12-22 years) enrolled in a drug rehabilitation program were examined. In 22 subjects four timed blood samples were obtained sequentially at 15 minute intervals for measurement of serum concentrations of testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and dehydroepiandrosterone sulfate (DHAS). The mean duration of DAA was 3.7 years, with marijuana and alcohol being the most frequently abused substances. The study subjects were compared to a matched control group of non-substance-abusing teenagers. All heights and weights of the DAA subjects fell within two standard deviations of the mean on the Tanner Growth Charts and no statically significant differences in the Tanner stages of sexual maturation were found between the DAA and control groups. The mean (+/- SD) testosterone level of the DAA group (221 +/- 109 ng/dl) was less than half that of the control group (477 +/- 193 ng/dl, p less than 0.001). Mean LH concentration in the DAA group (3.9 +/- 3.0 mIU/ml) was significantly less than that of the control group (10 +/- 4.9 mIU/ml, p less than 0.01). In both the DAA and control populations there was a significant (p less than 0.01) correlation between serum concentrations of LH and testosterone. The mean FSH level of the DAA group (3.3 +/- 1.1 mIU/ml) was significantly less (p less than 0.02) than that of the control group (4.7 +/- 1.9 mIU/ml). To assess the effects of treatment, six boys underwent repeat blood sampling 7-12 months after drug and alcohol withdrawal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗