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Biomedical subjects

W C Smith

Publications and source records attributed to W C Smith.

At least 199 records · Page 11Linked to original sources

Simplified subcutaneous fat biopsy for nutritional surveys.

Use of a 3 mm skin-biopsy punch results in skin plus an additional core of subcutaneous fat which is adequate for gas chromatographic analysis of fatty acids. This technique is quicker, cheaper and less traumatic than other methods of fat biopsy and is recommended for population surveys of diet where the pattern of fat intake is being investigated. It has been used in a survey for cardiovascular risk factors on some 3 000 subjects and has proved to be safe and acceptable.

Adipose Tissue↗

Influence of creep feeding and dietary intake after weaning on malabsorption and occurrence of diarrhoea in the newly weaned pig.

The influence the pattern of creep feeding has on the ability of pigs to absorb xylose after weaning at three weeks old was investigated. All weaned pigs showed a reduction in their ability to absorb xylose one week after weaning, but this was not influenced by the pattern of creep feeding before weaning. Diarrhoea occurred in some animals after weaning, but did not occur in pigs which did not have access to creep food before weaning. This protective effect of withholding creep food was associated with a low dietary intake after weaning with this regimen. Pigs which developed diarrhoea tended to be those which consumed more meal after weaning than their contemporaries. Haemolytic enterotoxigenic Escherichia coli and rotaviruses were present in the faeces of most pigs after weaning, but, in those animals that ate too much and developed diarrhoea, excretion of the E coli continued for approximately twice as long as in animals that remained healthy.

Animals↗

Comparison of response rates to a postal questionnaire from a general practice and a research unit.

A postal questionnaire study was carried out in an urban general practice to determine the effect of the introductory letter being sent by the participants' own general practitioner compared with that from a letter sent directly from a research unit. By sequential sampling 409 individuals aged between 40 and 59 were assigned to one of two groups. The people in one group were written to by their own general practitioner and those in the other by a doctor from a research unit. Husbands and wives were paired and were always sent the same letter. A second letter was sent to nonresponders after one month. The response rate to the general practitioner was significantly higher than that to the doctor in the research unit (85% compared with 75%) and differed by age and sex. The results have important implications for other research workers and suggest that general practitioners are in a key position in the conduct of medical and epidemiological research.

Adult↗

Plasma concentrations of LH, prolactin, oestradiol-17 beta and progesterone in sows weaned after lactation for 10 or 35 days.

Piglets were weaned from multiparous sows at 10 days (Group E; N = 7) or 35 days (Group C; N = 8) of lactation. Blood samples were collected at 8 h intervals from the day before weaning (Day--1) until and including the day of first mating, then once daily until 10 days post coitum. Additionally, 5 sows in each group were sampled at 30 min intervals for 12 h on Days--1, 0 and 1, then at 30 min intervals for 6 h daily until mating, finally at 30 min intervals for 2 h daily until 5 days post coitum. Group E sows had relatively longer weaning to remating intervals (8.3 +/- 0.8 compared with 5.0 +/- 0.7 days; P less than 0.01) and tended, but not significantly, to produce smaller subsequent litters (10.2 +/- 1.9 compared with 12.0 +/- 0.6). Sows in group E had lower lactational and post-weaning plasma LH levels (P less than 0.001). They also had greatly attenuated preovulatory LH rises and the area under the peak was reduced (P less than 0.01 and P less than 0.001, respectively). Preweaning plasma prolactin levels were higher at 9 days of lactation than at 34 days and levels in both groups dropped precipitously subsequent to piglet removal. Although peak levels of prolactin at oestrus did not differ between treatments, they tended to occur before the LH peak in sows of Group C and after the LH peak in Group E.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Effects of oestradiol benzoate treatment on the reproductive performance and endocrine status of sows after lactations of 10 or 35 days.

Forty-two Landrace X Large White sows were used in 3 studies of oestradiol benzoate treatment 24 h (E1) or 48 h (E2) after piglet removal, following lactations of 10 (S) or 35 (L) days, or were untreated controls (C). For Exp. 1, oestradiol benzoate doses were 4, 16 and 64 micrograms/kg body weight; since highest mean LH peaks followed use of the 16 micrograms/kg dose, this treatment was used in later studies. Treatments for Exp. 2 were S-E1 and L-E1 (N = 3). Pregnancy rates were 1/3 and 2/3, respectively, while 10-day weaned sows tended to have longer weaning-remating intervals, shorter oestrous periods and lower post-injection oestradiol peaks. Post-treatment LH peaks were recorded from all L-E1 sows, but only one S-E1 animal. Treatments S-E2, L-E2, S-C and L-C (N = 6) were used in Exp. 3; pregnancy rates were 1/6, 6/6, 5/6 and 6/6, respectively, while peak oestradiol levels were 49.5 +/- 8.3, 74.8 +/- 15.1, 21.7 +/- 2.0 and 51.8 +/- 26.5 pg/ml, respectively. Weaning-remating intervals were extended in S-C sows (P less than 0.05), while oestradiol treatment prolonged behavioural oestrus. LH peak values were reduced after short lactations, but not affected by oestradiol treatment. Plasma prolactin concentrations at weaning were higher in sows in treatment S than in treatment L, while at the subsequent oestrus in oestradiol-treated sows they were elevated more and for longer periods than in controls. These results demonstrate that reduced gonadotrophin secretion and fertility after short lactations are not overcome by treatment with oestradiol benzoate.

Animals↗

Assessment of the immunization status of practice children under five years of age.

Many professional groups are involved in immunization, and four different immunization records may be kept-the general practice record, the community child health record, the health visitor record and a record retained by the parent. The first three of these sources were examined for the immunization status of children under five years of age in a practice. The health visitor record was the most comprehensive. There was a remarkable improvement in pertussis vaccine acceptance over the four years reviewed but there were gaps in the uptake of measles vaccine.

Child, Preschool↗

Delayed hypersensitivity to mumps antigen in humans.

Sixty-one subjects, preselected for mumps sensitivity, were entered into a double-blind protocol to standardize Mumps Skin Test Antigen. Four lots of mumps antigen selected on the basis of in vitro potency tests were used. Four other antigens, Histoplasmin, Dermatophytin-O, Dermatophytin, and fluid tetanus toxoid were also tested; positive reactions for these four antigens occurred in 48, 68, 25, and 43% of individuals, respectively. The mumps lots exhibited delayed hypersensitivity with positivity ranging from 63 to 67% at 20 CFU/ml and 77 to 84% at 80 CFU/ml in the acceptable lots. Side effects were primarily local and minor in nature. Mumps Skin Test Antigen is a useful measure of the integrity of the immune system, but lacks complete specificity because of local dermal factors.

Adult↗

Hepatitis B virus infection: mortality, morbidity and the cost to the health service in Scotland.

This study assessed the size and character of hepatitis B virus infection in Scotland in 1980 by looking at laboratory reports, registration of deaths and hospital discharges. Less than half the laboratory reports of hepatitis B virus infection were associated with hepatic disorder and the overall attack rate in Scotland in 1980 was 2.8 per 100 000. The case fatality for active infection was 2.1 per cent. Most clinical cases were admitted to hospital and their mean duration of stay was 12.9 days. The cost of hospital treatment of hepatitis B virus infection in Scotland was considerably less than the equivalent cost in Europe, probably as a result of the lower cost of treatment and a lower attack rate in Scotland.

Adolescent↗

The induction of parturition in sows using prostaglandin F2alpha.

Intramuscular injections (10 mg) of prostaglandin F2alpha were administered to 19 pregnant sows in one herd on either the 112th or 113th day of gestation and a similar number of untreated sows served as controls. Induced sows for up to 6h after injection generally showed more walking, drinking defaceating and postural changes. Over the last 20 h prepartum they spent more time lying and urinated more frequently. Mean interval from injection to onset of parturition in treated sows was 24.5 h and 16 of them commenced farrowing during the working day, compared with 6 in the control group. Induction of parturition did not influence litter size at birth, piglet body-weights at birth or 14 days of age, the incidence of the mastitis, metrititis agalactae syndrome, re-breeding interval of the sow or size of the subsequent litter at birth. Farrowing time was significantly longer (6.48 h v 4.08 h) for treated sows and litter pre-weaning mortality was higher but not significantly so. Most piglet deaths in each group resulted from overlaying or starvation but mortality from anaemia and septicaemia occurred only in the treated group. It is considered that the technique could have practical application on well-managed intensive pig units.

Journal Article↗