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Biomedical subjects

G Carter

Publications and source records attributed to G Carter.

At least 91 records · Page 5Linked to original sources
PubMed1988

The Ha-ras polymorphism in myelodysplasia and acute myeloid leukaemia.

We have assessed the possibility that rare allelic variants of the c-Ha-ras-1 locus may be linked to a susceptibility to malignancy [1]. c-Ha-ras-1 genotypes were scored in 41 patients with myelodysplasia (MDS), 51 patients with acute myeloid leukaemia (AML) and 52 normal subjects. The incidence of rare alleles in the MDS patients was 4.8% and in AML an incidence of 15.7% was found. No rare alleles were found in the normal subjects. We conclude that rare alleles in MDS are not a common predisposing factor.

Alleles↗
PubMed1988

RAS mutations in myelodysplasia detected by amplification, oligonucleotide hybridization, and transformation.

Members of the RAS gene family have been implicated in many neoplasms with activating mutations around amino acid positions 12 and 61. We have assessed the mutational activation of H, K, and NRAS in myelodysplasia (MDS) by polymerase chain reaction and hybridization with synthetic oligonucleotide probes. Using this method, point mutations in codons 12/13 and 61 of these RAS genes were detected in 20 of 50 patients including two with refractory anemia with ringed sideroblasts (RARS). Ten normal individuals had no detectable RAS mutations. In 11 instances, DNA from patients with detectable RAS mutations were shown to register in either NIH3T3 focus-forming or nude mouse tumorigenicity assays. In addition, one patient (RARS) was shown to have an activated NRAS gene detected by a tumorigenicity assay and Southern blot analyses. Two MDS patients had mutations detected in two different RAS genes. DNA from one of these patients was observed to give rise to transformants with activated N and HRAS. Two patients with detectable NRAS mutations in the MDS stage progressed to AML and DNA from the AML stage registered positively in a transformation assay with NRAS activation. These results show that RAS mutations can occur at early, as well as late, stages of leukemic progression. The incidence of RAS mutations appears to be significantly higher in CMML than in the other subgroups (p = 0.02).

Adult↗
PubMed1987

Raised serum thyrotrophin in women with peripheral arterial disease.

Women with symptomatic peripheral arterial disease were screened for impaired thyroid function using a sensitive immunoradiometric assay for thyrotrophin (TSH). The arterial disease in the aortotibial segment was documented by an abnormal brachial/ankle pressure index in 80 patients. An age-matched control group of elderly women (n = 30) with a normal pressure index was established. In the control group the mean serum TSH was 1.6 +/- 1.1 milliunits/l, median 1.5 milliunits/l and this established a normal range of 0.2-3.9 milliunits/l. Seven patients (8.8 per cent) were already receiving treatment for myxoedema. In the remaining patients, the overall distribution of serum TSH was skewed to higher levels; the mean was 3.7 milliunits/l, median 2.4 milliunits/l, P less than 0.001 compared with controls and 15 (19 per cent) had a serum TSH greater than 4 milliunits/l, compared with only one (3.3 per cent) of the controls. Therefore 22 patients (28 per cent) had myxoedema or a raised serum TSH. For all subjects with a normal TSH, there was a positive correlation of serum TSH with serum cholesterol, r = 0.68, P less than 0.001. For patients with a raised TSH, there was a continuing, but non-linear, increase of serum cholesterol with TSH. These results suggest that a raised serum TSH may be one of the risk factors for the development of peripheral arterial disease in women, possibly by increasing cholesterol levels.

Aged↗
PubMed1987

Antianginal efficacy of carvedilol, a new beta-blocker with vasodilating action.

To evaluate the antianginal efficacy of carvedilol, a beta-blocker with vasodilating activity, we performed a randomized double-blind placebo-controlled study of two single doses of carvedilol. Twelve patients (eight males, four females, mean age 57 years) with stable effort angina and a positive exercise ECG with angina underwent treadmill exercise testing 2 h after either placebo, or carvedilol 25 or 50 mg. Both doses of carvedilol reduced resting heart rate but only the 50 mg dose reduced resting blood pressure. Exercise time and time to angina increased by 24% and 35%, respectively, after carvedilol, and ST depression at both maximal and submaximal work levels was reduced. The time to 1 mm ST depression was increased by carvedilol but the heart rate at 1 mm ST depression and maximum ST/heart rate slope were unchanged. Maximum heart rate, systolic pressure, and rate-pressure product were significantly reduced by carvedilol. The 50 mg dose was significantly better than 25 mg in prolonging exercise time and reducing subjective and objective measurements of ischemia, and this was related to significantly greater hemodynamic effects. Carvedilol appears to be effective in preventing or reducing effort angina due to reduced myocardial oxygen demand, and it exhibits an important dose-response effect.

Adrenergic beta-Antagonists↗
PubMed1986

The impact of aeromedical helicopter programs on emergency medicine resident training: resident attitudes, perceived risks, and benefits.

Using emergency medicine residents as helicopter flight physicians is a recent evolution in residency training. In an effort to study the impact such a system has on residents in emergency medicine, residents participating in helicopter transport were surveyed at 10 programs in the United States. The potential survey field was 118 residents with (81%) responding. Generally helicopter transport was perceived to be educational (80%), enjoyable (88%), and safe (74%). A total of 75% felt that benefits of transport outweighed the risks, despite an increase in aeromedical helicopter fatalities in 1985. In six of ten programs residents wore shoulder restraints, in two they wore helmets, and in no program were fire-retardant clothing worn on a regular basis. Of the 72 residents involved in mandatory participation, 69% would continue flying in a voluntary system. Although it is clear that selected patients benefit from aeromedical transports, refined triage protocols as well as further studies to identify the costs and benefits of such transport programs to participating emergency medicine residents are needed. Flight safety equipment including helmets, shoulder-harness restraints, and fire-retardant suits are underutilized at all programs surveyed.

Aircraft↗
PubMed1985

The effect of spironolactone on hirsutism and female androgen metabolism.

An objective evaluation of the anti-androgen effects of spironolactone was performed in a consecutive series of 12 hirsute patients receiving a daily dose of 150 mg; nine completed the study. Using a computer assisted image analyser, hair diameter on two weekly shavings decreased significantly over a 12 month period in three of the patients, although growth rate and mean diameter did not change in the group as a whole. Plasma testosterone fell significantly to a mean of 53% of basal levels. The mean free testosterone (derived) fell significantly to 64% of basal by the sixth month (P = less than 0.005) and remained significantly depressed the remainder of the study. There was subjective benefit in hair growth and greasiness and a significant reduction in the semi-objective Ferriman-Gallwey index in nine of 10 subjects assessed for at least 9 months. We conclude that although spironolactone was not consistently successful, it may represent effective therapy for a sub group of patients with hirsutism.

Adolescent↗
PubMed1985

Ageing in Down's syndrome.

In a group of 23 hospital patients aged over 50 with Down's syndrome, psychological testing indicated that significant intellectual deterioration, which was un-related to chronological age, sex, length of hospitalisation, or earlier mental age, had occurred in nine. Clinically, there was no evidence in any patient of active physical illness, focal neurological signs, or dementia, but significant associations were found between intellectual deterioration and decreased visual acuity, hearing loss, and macrocytosis.

Aging↗
PubMed1984

The membrane capacity of mammalian skeletal muscle fibres.

Membrane capacity was measured as a function of fibre diameter in mammalian skeletal muscle fibres under normal conditions and under conditions designed to reduce the membrane chloride conductance, i.e. in solutions in which chloride ions were replaced by sulphate or methylsulphate ions, or in normal Krebs solutions containing 2,4-dichlorophenoxyacetic acid (2.5 mM). The experiments were done on rat sternomastoid, extensor digitorum longus and soleus muscle fibres. The average membrane capacity of fibres in each muscle was greater than normal when chloride conductance was reduced and the slope of the relationship between membrane capacity and fibre diameter increased. The results were consistent with the hypothesis that the space constant of the transverse tubule system in mammalian fibres is normally short because the transverse tubule membrane has a high chloride conductance. The experimental results imply that the space constant of the transverse tubule system was less than 40 microns for fibres in normal Krebs solution and greater than 100 microns for fibres with low membrane chloride conductance. The space constant was calculated using measured geometrical parameters of the transverse tubule, and measured membrane conductance, and the values were close to 20 microns for fibres in normal Krebs solution and between 50 and 120 microns for fibres with low chloride conductance.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1984

Sudden deaths in the mentally handicapped.

Trends in the incidence and causes of sudden deaths in a hospital group for the mentally handicapped were identified during a 50-year period, and the two halves of the period were compared. There were significantly more deaths in the second 25-year period than in the first. Longevity was greater during the second period, and a decrease in deaths due to status epilepticus was outweighed by an increase in deaths from arterial degenerative disease in the larger number of older patients. In the second period there was also a significant rise in sudden deaths due to asphyxia, probably attributable to modern medication with side-effects giving rise to feeding difficulties.

Adult↗
PubMed1984

Oral spironolactone improves acne vulgaris and reduces sebum excretion.

In a consecutive series of thirty-six male and female patients referred with severe acne, the effect of 3 months' treatment with placebo or spironolactone (50-200 mg daily) on sebum excretion and clinical and endocrine status was evaluated double-blind. Twenty-six patients completed the study. Abnormal free androgen indices were found in 27% of the original nineteen female subjects. Spironolactone reduced sebum excretion in all female subjects, but there was no correlation between sebum response and androgen status. The clinical response was dose-dependent, with maximum subjective and objective benefit when spironolactone doses of 150-200 mg were used.

Acne Vulgaris↗
PubMed1984

Hypocholesterolaemia in cancer and other causes of death in the mentally handicapped.

Serum cholesterol levels were estimated in 313 mentally handicapped patients who subsequently died from various causes. Although cholesterol levels in the mentally handicapped are lower than those in the general population, it was found that there was still an association between relatively low serum cholesterol values and mortality due to cancer of the colon. Similarly, patients who died from myocardial infarction had relatively high serum cholesterol levels. The mechanism of the relationship between hypocholesterolaemia and cancer of the colon is unclear, but the increasing longevity of the mentally handicapped is an important factor which has contributed to a rising incidence of cancers, particularly gastrointestinal forms, in this group.

Aged↗
PubMed1984

Why are the mentally handicapped admitted to hospital? A ten-year survey.

Admissions of mentally handicapped patients over a ten-year period to a hospital group with a catchment area population of 213,000 are described and discussed. During this time, there was a progressive increase in temporary admissions for assessment, day care, and for both planned and emergency respite care. There were also 89 admissions for permanent care associated with conditions such as psychiatric disorder, multiple handicap, and changed family circumstances.

Adolescent↗
PubMed1983

Mortality in the mentally handicapped: a 50 year survey at the Stoke Park group of hospitals (1930-1980).

Mortality trends during the past 50 years in the population of a hospital group for the mentally handicapped are reported. There has been a marked change in the causes of death during this period. Whilst tuberculosis is no longer a major cause, other terminal respiratory tract infections are still prevalent. Deaths due to status epilepticus have decreased, with a concomitant increase in those due to carcinoma, myocardial infarction and cerebrovascular accident. Similarly, the mortality rate has altered significantly. Fifty years ago the patients' mortality was considerably higher at all age groups in comparison with the general population, whereas the difference is now relatively small. These changes have been most marked during the past 25 years, with the introduction of new drug therapy, better diet, care and environment for the mentally handicapped. The result of this is increased longevity in the mentally handicapped, in particular in those with Down's syndrome whose longevity has increased by 40 years, and over 30 years in others. These findings have important implications for the planning of future services for the ageíng mentally handicapped population, in hospital and in the community alike, with associated geriatric ailments, and pre-senile and senile dementias.

Adolescent↗
PubMed1983

The abrupt withdrawal of antiparkinsonian drugs in mentally handicapped patients.

Long-term antiparkinsonian medication given to 20 mentally handicapped patients also on neuroleptics was abruptly withdrawn. Transient extrapyramidal signs developed in most patients during the following four weeks but in 60 per cent had disappeared by 12 weeks. Reintroduction of medication was necessary in only three patients, who developed acute dystonic reactions within one week of withdrawal.

Adolescent↗