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Biomedical subjects

D MacDonald

Publications and source records attributed to D MacDonald.

At least 109 records · Page 6Linked to original sources
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

Cesarean section and perinatal outcome: response from the House of Horne.

A direct comparison between Parkland Memorial Hospital in Dallas, Texas, and the National Maternity Hospital in Dublin, Ireland, on the basis of limited numbers taken from one year only (1983) led to the conclusion that the liberal use of cesarean section in Dallas was associated with a sevenfold decrease in intrapartum fetal deaths and a twofold decrease in neonatal seizures. However, when the scope of the survey is extended to include the year before (1982) and the year after (1984), a different picture emerges. During this extended period there were almost four times as many cesarean sections performed in Dallas with no significant difference in overall perinatal mortality, while for two of three years the incidence of neonatal seizures was twice as high in Dallas when compared with Dublin. The fact that high cesarean rates continue to rely on evidence of such a tenuous nature must remain a matter of concern.

Adult↗
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

Reduction of asthenopia after accommodative facility training.

Five patients reporting asthenopia secondary to accommodative deficiencies underwent automated accommodative facility training. A matched-subjects, crossover design was used to control for placebo effects. All patients receiving automated accommodative training showed a marked increase in accommodative amplitude along with a concurrent reduction of asthenopia. Decreases of blur and increases of reading time were the most frequently reported changes by patients. This experiment shows the effectiveness of automated accommodative training in reducing asthenopia and improving accommodative facility.

Accommodation, Ocular↗
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↗
PubMed1985

The Dublin randomized controlled trial of intrapartum fetal heart rate monitoring.

In a randomized controlled trial involving 12,964 women, a policy of continuous electronic intrapartum fetal heart monitoring was compared with an alternative policy of intermittent auscultation, both policies including an option to measure fetal scalp blood pH. Women allocated to electronic fetal heart monitoring had shorter labors and received less analgesia. The caesarean delivery rates were 2.4% for electronic fetal heart monitoring and 2.2% for intermittent auscultation but this small difference arose from the identification of nearly twice as many fetuses with low scalp pH (less than 7.20) in the electronic fetal heart monitoring group. The forceps delivery rate was 8.2% in the electronic fetal heart monitoring group compared with 6.3% in the intermittent auscultation group, and this excess was explained by more instrumental deliveries prompted by fetal heart rate abnormalities. There were 14 stillbirths and neonatal deaths in each group, with a similar distribution of causes. There were no apparent differences in the rates of low Apgar scores, need for resuscitation, or transfer to the special care nursery. Cases of neonatal seizures and persistent abnormal neurological signs followed by survival were twice as frequent in the intermittent auscultation group, and this differential effect was related to duration of labor. Follow-up at 1 year of babies who survived neonatal seizures revealed three clearly abnormal infants in each group. The implications of these findings for both theory and practice are discussed.

Adult↗