Search PubMed⌕ Search

Biomedical subjects

A Whitelaw

Publications and source records attributed to A Whitelaw.

At least 127 records · Page 7Linked to original sources
PubMed1979

A study of the effects of copper deficiency in Scottish blackface lambs on improved hill pasture.

One member of each pair of twin lambs from 37 five-and six-year-old Scottish blackface ewes, grazing reseeded pasture suspected of causing a molybdenum-sulphur induced copper deficiency in sheep, was given an injection of 12.5 mg copper calcium edetate at about eight weeks of age. Plasma copper concentrations of these lambs were maintained in the normal range by further injections of copper as required (treatment group). The remaining member of each twin pair received no copper therapy (control group). The control lambs and all ewes showed marked hypocupraemia throughout lactation, whereas the plasma copper concentrations of the treatment lambs, and also of single lambs with continuous access to unimproved hill grazings, remained normal. The live-weight gain of the treatment lambs was significantly greater than that of the control lambs, the difference in mean live-weights after 12 weeks being 2.5 kg. All lambs showed some degree of osteoporosis; this was most severe in the control lambs which had less dense bones and were also more susceptible to bone fractures and to disease. Differences between treatment and control lambs were also observed in haematological parameters and in fleece characteristics.

Animals↗
PubMed1977

Infant feeding and subcutaneous fat at birth and at one year.

Skin folds were measured at birth and at 1 year in infants who were obese, normal or thin at birth, infants of obese mothers and infants of diabetic mothers. There was no significant correlation between skinfold thickness at birth and skinfold thickness at 1 year and there was no significant difference in skinfold thickness between any of the groups at 1 year of age. These findings are not consistent with the hypothesis that overnutrition in the last 10 weeks of pregnancy has a permanent effect on the adiposity of the infant. The distributions of triceps and subscapular skinfolds in these 1-year-old infants were considerably lower than in a 1967-68 survey of British 1-year-olds. In this (1976) survey, the breast-feeding rate (40% at 2 months) and the mean age of introduction of solids (15 weeks) were both greater than in previous British surveys. Recent warnings against overfeeding in infancy may be changing feeding practices, resulting in slimmer 1-year-old children.

Adipose Tissue↗
PubMed1977

Histocompatibility linked immune responsiveness and restrictions imposed on sensitized lymphocytes.

Delayed-type hypersensitivity (DTH) transfer to GAT was restricted by the I-A region of the major histocompatibility complex (MHC). Sensitized cells from F1 hybrid mice between responder and nonresponder strains transferred DTH to syngeneic F1 mice and to naive parental strain recipients of the responder but not of the nonresponder haplotypes. These results are interpreted to favor the postulate that the MHC-linked Ir genes exert their effects by coding for components which allow interactions between particular I region gene products and the region to form stable structures immunogenic for DTH T cells.

Alanine↗
PubMed1977

A study of a strategic dosing programme against ovine fascioliasis on a hill farm.

In a farm-scale veterinary preventive programme run from 1973 to 1976 the use of rafoxanide (Flukanide; Merck Sharp & Dohme) in the prophylaxis of ovine fascioliasis resulted in a marked reduction in the percentage of ewes passing fluke eggs in the faeces and an absence of clinical cases of fascioliasis throughout these years. Three separate flocks of hill sheep were used in this study in which the aim of the dosing programme followed was to kill the majority of liver flukes (Fasciola hepatica) before they reached adult egg laying stage, thereby eliminating, or considerably reducing, the number of eggs passed on to the pasture.

Animals↗
PubMed1977

Subcutaneous fat in newborn infants of diabetic mothers: An indication of quality of diabetic control.

Biceps, triceps, subscapular, and suprailiac skinfolds were measured in 40 newborn infants of diabetic mothers. Maternal fasting blood-glucose and mean blood-glucose in the third trimester correlated significantly with neonatal skinfold thickness. Skinfold measurement, when compared with a reference range for gestational age, may be a convenient way of assessing one effect of maternal diabetes on the fetus. Gluteal adipose-cell diameter was measured in 31 infants of diabetic mothers. The fattest babies had the largest adipose cells and there was a significant positive correlation between maternal fasting blood-glucose and neonatal adipose cell diameter. These findings are consistent with the hypothesis that in diabetic pregnancy fetal hyperglycaemia and hyperinsulinism stimulate increased triglyceride synthesis in adipose cells and enlargement of adipose cells and lead to an increase in fetal subcutaneous fat.

Adipose Tissue↗
PubMed1976

Role of major histocompatibility complex gene products in delayed-type hypersensitivity.

Sensitized thymus-derived (T) lymphocytes can transfer delayed-type hypersensitivity (DTH) to naive mice only if there is identity at the major histocompatibility complex (MHC). The MHC region responsible differs according to the antigen used for sensitization. For transfer of DTH to fowl gamma globulin identity at I-A is necessary; for dinitrofluorobenzene, however, identity at either K, D, or I region is sufficient. T cells of one genotype, sensitized in a chimeric environment, transferred DTH to both parental strains even though these were MHC incompatible. However T cells from F1 hybrid mice, sensitized not in the F1 but in one parental strain, transferred DTH only to that parental strain, not to the other, in contrast to F1 T cells sensitized in the F1 which could transfer DTH to both parental strains. Macrophages pulsed with antigen in vitro could be used to sensitize syngeneic or semi-allogeneic mice for the transfer of DTH. Transfer was, however, successful only in the strain syngeneic to that from which the macrophages were derived. Evidence is also presented that genetically low-responder mice can be made to exhibit DTH provided they are pretreated with cyclophosphamide two days before sensitization. When considered in toto these results strongly argue in favor of the notion that there are receptors on activated T cells which recognize antigenic determinants and MHC gene products. The implications of these findings are discussed in relation to the role of macrophages in antigen presentation and to the possible parallel evolution of MHC gene products and of T cell receptors for antigen.

Animals↗
PubMed1976

Occlusion pressures in men rebreathing CO2 under methoxyflurane anesthesia.

The effect of general anesthesia on control of breathing was studied by CO2 rebreathing and occlusion pressure measurements in six normal human subjects under methoxyflurane anesthesia. CO2 was found to increase the amplitude of the occlusion pressure wave without changing its shape, so that CO2 responses in terms of the occlusion pressure developed 100 ms after the onset of inspiration (Po/0.1) gave results equivalent to the responses in terms of Po/1.o or any other parameter of the pressure wave. Methoxyflurane depressed the ventilatory response to CO2 but not the occlusion pressure response, implying that the most important action of the anesthetic was to increase the effective elastance of the respiratory system rather than to depress the respiratory centers. The elastance was further increased by CO2, and this mechanical change had the effect of shifting the "apneic threshold" extrapolated from the ventilatory response curve to a lower PAco2. Frequency of breathing, inspiratory and expiratory times were not altered by CO2 in anesthetized subjects.

Adult↗
PubMed1975

Investigation into diagnosis and treatment of cobalt deficiency in lambs.

The development of cobalt deficiency was studied in 30 Scottish Blackface lambs grazing pasture on a soil containing 0-17 ppm cobalt. By the end of an eight-week period 50 per cent of lambs were subjectively appraised as showing signs of cobalt deficiency. After a further period lasting four weeks, during which three groups of lambs were studied (one group, least affected by cobalt deficiency, acted as control, the second received a single cobalt bullet and the third received oral doses of 200 mg cobalt chloride at the beginning of the period and three weeks later). Mean urinary formiminoglutamic acid (FIGLU) concentrations were inversely related to serum vitamin B12 concentrations and increased from 0-08 to 0-20 mumole per ml in group 1, and decreased to virtually zero within one week of treatment in groups 2 and 3. The use of serum vitamin B12 and urinary FIGLU concentrations in the diagnosis of cobalt deficiency in sheep are discussed.

Administration, Oral↗