Search PubMed⌕ Search

Biomedical subjects

G D Smith

Publications and source records attributed to G D Smith.

At least 307 records · Page 17Linked to original sources
PubMed1995

Effect of the somatostatin analogue, octreotide, on exercise-induced hypotension in human subjects with chronic sympathetic failure.

1. In autonomic failure, supine exercise lowers blood pressure and worsens postural hypotension. The somatostatin analogue, octreotide, reduces post-prandial and postural hypotension, but its effects on exercise-induced hypotension and on postural hypotension post-exercise are unknown. 2. Eighteen subjects with chronic sympathetic denervation were studied; 12 had pure autonomic failure and six had additional neurological features of the Shy-Drager syndrome. Haemodynamic, hormonal and biochemical changes were measured before, during and after incremental supine leg exercise on two occasions: on no treatment and after subcutaneous octreotide. Exercise was performed 120 min after octreotide in eight subjects and 60 min after octreotide in ten subjects. 3. Octreotide did not improve exercise-induced hypotension; the blood pressure fall was greater during exercise, but the blood pressure level was no different than without treatment. Heart rate, stroke distance, cardiac index and systemic vascular resistance were similar at rest and changed to the same degree with exercise on and off octreotide. After octreotide, resting levels of serum growth hormone, plasma noradrenaline, adrenaline and renin were unchanged, but glucose was higher and insulin was lower. There was no change in biochemical and hormone levels during exercise either off or on octreotide. 4. After octreotide, although the rate of blood pressure recovery was similar post-exercise, the levels of blood pressure were higher than in the non-treatment phase and postural hypotension was improved before and after exercise. 5. In conclusion, in primary autonomic failure, octreotide did not improve exercise-induced hypotension in the supine position, suggesting that octreotide-sensitive vasodilatory peptides do not contribute to the blood pressure fall.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

BULLET: a computer simulation of shotgun DNA sequencing.

BULLET is a computer program that simulates shotgun sequencing of DNA. The program has been used to simulate the sequencing of DNA fragments from 2 to 30 kb. To obtain 80% single or double-stranded sequence, a doubling of the DNA fragment size necessitates twice the number of sequencing reactions. However, a similar linear relationship does not apply to the determination of 100% single or double-stranded sequence. Data from BULLET were used to derive simple linear formulae that estimate the number of sequencing reactions necessary to partially sequence a fragment of DNA irrespective of size. When 80% of the double-stranded sequence has been determined, approximately 98% of single-stranded sequence will be known. This is a reasonable point to change to a more directed strategy of DNA sequencing.

Algorithms↗
PubMed1995

Structure and properties of a herpesvirus of turkeys recombinant in which US1, US10 and SORF3 genes have been replaced by a lacZ expression cassette.

In the process of generating an insertional mutant of herpesvirus of turkeys (HVT) expressing lacZ at the protein kinase (PK) locus, we isolated a recombinant which contained an intact PK gene but the short unique regions US1, US10 and SORF3 had been deleted and replaced by the lacZ cassette. Moreover, the virus contained duplicate copies of gD, gI and gE in an opposite orientation flanking lacZ, US2 and PK which were contiguous. These results are of interest in relation to the flexibility of the short unique segment (Us) and of the inverted repeats flanking Us of the alpha-herpesviruses. The recombinant expressed beta-galactosidase and was genetically stable in vitro and in vivo. Chickens inoculated with the virus developed antibodies to HVT antigens and to beta-galactosidase but the replication of the recombinant in vivo was impaired in comparison to parental HVT as shown by a reduction in the proportion of infected lymphocytes.

Animals↗
PubMed1995

Adult height and mortality in London: early life, socioeconomic confounding, or shrinkage?

STUDY OBJECTIVE: To examine in detail the cause specific associations between height and mortality. DESIGN: A prospective cohort study with an 18 year mortality follow up. SETTING AND PARTICIPANTS: The Whitehall study of 18,403 men in the civil service in London examined between 1967 and 1969 aged 40-64 and followed up for mortality until the end of January 1987. MAIN RESULTS: There was considerable variation in the strength of height-mortality association by cause. Respiratory disease showed the strongest inverse association, cardiovascular disease a moderate effect, and all neoplasms virtually no effect. Adjustment for age and civil service grade reduced the strength of these associations slightly, but had no impact on the heterogeneous pattern by cause (chi 2 3df p < 0.001). The height-mortality association declined with the length of follow up. By 15+ years, the only appreciable height affect was for respiratory disease mortality. CONCLUSIONS: The attenuation of the height-mortality association with length of follow up might be explained by differential height reduction before entry that was greatest for people who were already ill, and hence at greatest risk of dying. The cause specific variation in the height-mortality association lends little support to the contention that impaired growth in childhood is a marker of general susceptibility to disease in adulthood.

Adult↗
PubMed1995

Cardiorespiratory disease in men and women in urban Scotland: baseline characteristics of the Renfrew/Paisley (midspan) study population.

UNLABELLED: STUDY OBJECTIVE. To describe the distribution of risk factors, risk behaviors, symptoms and the prevalence of cardiorespiratory disease in men and women in an urban area with high levels of socioeconomic deprivation. A cross-sectional survey of 15,411 men and women aged 45-64, comprising an 80% response rate from the general population in Paisley and Renfrew, Scotland. MAIN RESULTS: The main characteristics of the male Renfrew/Paisley population, compared to previous British studies, were shorter stature, higher blood pressure, a higher proportion of smokers who continue to smoke, lower FEV1 and higher levels of reported angina, breathlessness on effort and chronic bronchitis. In comparison with men, the main characteristics of the female Renfrew/Paisley population were shorter stature, higher plasma cholesterol, lower FEV1, fewer current and ex-smokers, and a higher prevalence of breathlessness on effort. There were only small differences between men and women in the prevalence of angina, ECG evidence of myocardial ischaemia and chronic bronchitis. CONCLUSIONS: Middle-aged men and women in an urban area with high levels of socio-economic deprivation have different cardio-respiratory risk and disease profiles compared to previous population in the UK, based on occupational groups and random national samples.

Angina Pectoris↗
PubMed1995

Risk factors for cardiorespiratory and all cause mortality in men and women in urban Scotland: 15 year follow up.

STUDY OBJECTIVE: To describe the relationship between risk factors, risk behaviours, symptoms and mortality from cardiorespiratory diseases in an urban area with high levels of socioeconomic deprivation. A cohort study of 15,411 men and women aged 45-64, comprising 80% of the general population of Paisley and Renfrew, Scotland. OUTCOMES: Mortality after 15 years from coronary heart disease(ICD 410-4), stroke(ICD 430-8), respiratory disease(ICD 460-519) and all causes. MAIN RESULTS: Mortality rates from all causes were 19% in men aged 45-49, 31% in men aged 50-54, 42% in men aged 55-59 and 57% in men aged 60-64. The rates are considerably higher than those reported in previous UK prospective studies. For women the rates were 12%, 18%, 25% and 38% respectively. In general men and women showed similar relationships between risk factor levels and mortality rates. People in manual occupations had higher mortality rates. Raised levels of systolic and diastolic blood pressure were associated with increased coronary, stroke and all cause mortality rates. Plasma cholesterol had no such association with all cause mortality rates. High and low levels of body mass index were associated with higher mortality rates than intermediate levels. A relationship between short stature and increased mortality rates was observed in men and women. FEV1 expressed as a percentage of the expected value showed the strongest relationship with mortality rates, particularly for respiratory disease, but also for deaths from coronary heart disease, stroke and all causes. CONCLUSIONS: A similar pattern of relationship between risk factor levels and mortality rates exists in men and women in Renfrew and Paisley. Respiratory impairment as measured by FEV1% predicted appears to be the most likely explanation of the observed high all cause mortality rates in this population.

Blood Pressure↗
PubMed1995

Examination of the effects of emotional disturbance and its detection on general practice patients' satisfaction with the consultation.

BACKGROUND: A patient's satisfaction with a consultation may be influenced by many factors relating to both patient and doctor. AIM: This study set out to examine the effects of emotional disturbance and its detection on general practice patients' satisfaction with the consultation. METHOD: A prospective study involving 893 adult patients attending 12 general practitioners in Glasgow was carried out. Questionnaires were completed by general practitioners after consecutive surgery consultations. Patients completed forms assessing mental state and satisfaction with inter-personal aspects of the consultation. RESULTS: Patients reporting frank psychological disturbance tended to express more dissatisfaction with the inter-personal aspects of the consultation. This effect was alleviated in the majority by recognition of the disturbance by the general practitioner. General practitioners differed markedly in their assessment of the psychological component of consultations. Fewer dissatisfied patients were found in the surgeries of doctors who tended to rate the psychological component of consultations more highly. In contrast, the general practitioner's overall accuracy of diagnosis of psychological distress was a poor predictor of the proportion of dissatisfied patients. CONCLUSION: This preliminary study suggests that a tendency among doctors to assign importance to the psychological component of consultations may enhance elements of patient satisfaction. It is not clear whether this [psychological-mindedness' is an attribute which can be learnt. To resolve this uncertainty, studies are needed of the effects on patients of educational interventions designed to increase general practitioners' sensitivity to psychological distress.

Adult↗
PubMed1995

Postural hypotension enhanced by exercise in patients with chronic autonomic failure.

The effect of supine exercise on blood pressure (BP), measured while recumbent and after head-up postural change, was investigated in three groups with marked postural hypotension due to chronic autonomic failure: 15 with associated neurological impairment (Shy-Drager syndrome, SDS, multiple system atrophy); 15 with pure autonomic failure (PAF) and two with a deficiency of the enzyme dopamine beta hydroxylase (DBH deficiency). Fifteen normal subjects were controls. In controls, exercise increased supine BP, and there was no postural fall before or after exercise. In SDS and PAF, however, exercise produced a substantial fall in BP, which was greater in PAF. In both groups, BP fell to a lower level on standing after than before exercise. In DBH deficiency, there was little change in BP with exercise, but BP fell to a lower level on standing after exercise. In all three groups with autonomic failure, there were more symptoms of postural hypotension on standing after exercise. The influence of exercise on both supine and postural BP, therefore, should be considered in the clinical and laboratory assessment of autonomic dysfunction.

Aged↗
PubMed1995

[Childhood diarrhea in rural Nicaragua: beliefs and traditional health practices].

In Nicaragua, the principal cause of infant mortality is diarrhea, which is responsible for 40% of these deaths annually. This statistic reflects the low usage of health services and oral rehydration therapy (ORT). In an effort to improve the situation, several studies were carried out in Villa Carlos Fonseca municipio. This report describes two of those studies, one ethnographic and the other epidemiologic (conducted in 1989 and 1990, respectively), to find out beliefs and traditional health practices and their influence on the way in which mothers responded to their children's diarrheal illness. The ethnographic study involved interviewing 70 mothers with an average age of 28 years who had children under 2 years of age. The children represented two groups: one at high risk for diarrhea and the other at low risk. The objectives were to learn the traditional names for diarrhea, the perception of risk, and the treatments that were used. The epidemiologic study included 391 mothers over 14 years of age with one or more children under age 5 years, of whom 215 had had diarrhea in the two weeks preceding the survey. The objectives were to describe local beliefs and health practices and to determine the incidence of diarrheas according to the diagnosis made by the mothers. At least 12 types of diarrhea were identified, for which terms such as "empacho" and "sol de vista" were used. In most cases, the mothers had more confidence in folkloric treatments that they themselves or the traditional healers (curanderos) applied than in the services offered at health centers. This attitude limited their use of health services and ORT, although it was observed that in certain cases traditional treatments were used in combination with those of western medicine. There was a direct but nonsignificant correlation between the level of schooling of the mothers and the frequency with which they visited the health center. The authors suggest the effects of massages, herbal baths, and other traditional treatments should be studied to evaluate their effectiveness and adapt them, to the extent possible, to "modern" medicine. Health services providers should become familiar with traditional nomenclature and beliefs in order to be able to communicate better with mothers and steer them away from harmful practices toward improved results in infant diarrheal disease prevention programs.

Adult↗
PubMed1994

Birth weight and later socioeconomic disadvantage: evidence from the 1958 British cohort study.

OBJECTIVE: To investigate the relation between birth weight and socioeconomic disadvantage during childhood and adolescence in a birth cohort study. DESIGN: Longitudinal analysis of birth weight in relation to social class, household amenities and overcrowding, and financial difficulties as reported by parents at interview when participants were aged 7, 11, and 16 years; and receipt of unemployment or supplementary benefits as reported by participants at age 23. SUBJECTS: Male participants in the 1958 birth cohort (national child development study) born to parents resident in Great Britain during the week of 3-9 March 1958. Data on birth weight and financial difficulties between birth and 23 years were available for 4321; data on housing conditions and social class at ages 7, 11, and 16 years were available for 3370. MAIN OUTCOME MEASURES: Socioeconomic disadvantage at later ages in men weighing 6 lb (2721g) or under at birth compared with those weighing over 6 lb and between fifths of the distribution of birth weight. RESULTS: Cohort members who weighed 6 lb or under at birth were more likely to experience socioeconomic disadvantage subsequently. Those in lower fifths of the distribution were more likely to experience socioeconomic disadvantage. CONCLUSION: Low birth weight is associated with socioeconomic disadvantage in childhood and adolescence. Studies of the association of indicators of early development and adult disease need to take into account experiences right through from birth to adulthood if they are to elucidate the combination of risks attributable to developmental problems and socioeconomic disadvantage.

Adolescent↗
PubMed1994

The structure of a complex of hexameric insulin and 4'-hydroxyacetanilide.

X-ray crystallographic studies have been carried out on human insulin crystals grown in the presence of 4'-hydroxyacetanilide (Tylenol) and show that this nontoxic phenolic derivative can induce the T-->R transition, producing a T3R3 hexamer. Two different crystals, grown under different conditions, are rhombohedral, space group R3, with cell constants a = 81.11, c = 37.97 and a = 80.88, c = 37.60 A. The T3R3 hexamer is symmetric, resulting from the presence of a crystallographic threefold axis, and the asymmetric unit consists of a TR dimer. Data to a resolution of 1.9 A were measured on a crystal from each of the two crystallizations and the structures have been refined to residuals of 0.168 and 0.173. The guest molecule is bound by the R-state monomer through the formation of two hydrogen bonds from the hydroxy group of Tylenol to the carbonyl oxygen and the nitrogen of A6 Cys and A11 Cys, respectively. Due to steric constraints of the phenolic binding site, the acetamide group of Tylenol is rotated approximately 50 degrees out of the plane of the phenyl group and the methyl group is cis; no hydrogen bonds exist between the acetamide group and the hexamer. Although the zinc ion, which is bound to the R-state trimer, has tetrahedral coordination in both structures, the T-state zinc is observed to have octahedral coordination in one structure but tetrahedral coordination in the other. The side chain of A10 Ile in the R-state monomer adopts a high-energy conformation as a result of close contact to a residue in an adjacent dimer and may explain in part the differences between therapeutic preparations of beef insulin, for which A10 is a Val residue, and human insulin.

Acetaminophen↗