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Biomedical subjects

M MacPherson

Publications and source records attributed to M MacPherson.

8 recordsLinked to original sources
PubMed2001

Physiological bases of genetic differences in cannibalism behavior of the confused flour beetle Tribolium confusum.

Physiological causes of genetic differences in cannibalism were examined to gain a better understanding of constraints on behavior evolution. Cannibalism has complex population level consequences in Tribolium confusum, including dramatic effects on population size. Laboratory strains with low and high cannibalism rates, obtained through inbreeding, have maintained distinct levels of cannibalism for over two decades even in the absence of artificial selection to maintain the differences. Why strains differ in their cannibalism rates was examined by measuring: (1) the nutritional benefit from cannibalism in both nutritionally good and poor environments, and (2) the possibility that eggs are an important source of water. How strains achieve differences in cannibalism was examined by testing for differences between strains in their ability to find eggs and in their tendency to eat eggs. Beetles from both strains survive equally well in a nutritionally good environment, but they accomplish this in different ways. The low cannibalism strain has high survivorship with and without cannibalism. The high cannibalism strain has low survivorship when not fed eggs and survivorship equivalent to the low cannibalism strain when fed eggs, suggesting it compensates for poor nutritional adaptation by eating eggs. The strains also differ in feeding behavior; beetles from the high cannibalism strain have a higher appetite for eggs. Beetles from the two strains did not differ in locomotor activity, search efficiency, or need for water. The observed behavioral and nutritional differences may contribute to the maintenance of different levels of cannibalism.

Animals↗
PubMed2000

A novel Drosophila alkaline phosphatase specific to the ellipsoid body of the adult brain and the lower Malpighian (renal) tubule.

Two independent Drosophila melanogaster P(GAL4) enhancer-trap lines revealed identical GAL4-directed expression patterns in the ellipsoid body of the brain and in the Malpighian (renal) tubules in the abdomen. Both P-element insertions mapped to the same chromosomal site (100B2). The genomic locus, as characterized by plasmid rescue of flanking DNA, restriction mapping, and DNA sequencing, revealed the two P(GAL4) elements to be inserted in opposite orientations, only 46 bp apart. Three genes flanking the insertions have been identified. Calcineurin A1 (previously mapped to 21E-F) lies to one side, and two very closely linked genes lie to the other. The nearer encodes Aph-4, the first Drosophila alkaline phosphatase gene to be identified; the more distant gene [l(3)96601] is novel, with a head-elevated expression, and with distant similarity to transcription regulatory elements. Both in situ hybridization with Aph-4 probes and direct histochemical determination of alkaline phosphatase activity precisely matches the enhancer-trap pattern reported by the original lines. Although the P-element insertions are not recessive lethals, they display tubule phenotypes in both heterozygotes and homozygotes. Rates of fluid secretion in tubules from c507 homozygotes are reduced, both basally, and after stimulation by CAP(2b), cAMP, or Drosophila leucokinin. The P-element insertions also disrupt the expression of Aph-4, causing misexpression in the tubule main segment. This disruption extends to tubule pigmentation, with c507 homozygotes displaying white-like transparent main segments. These results suggest that Aph-4, while possessing a very narrow range of expression, nonetheless plays an important role in epithelial function.

Alkaline Phosphatase↗
PubMed1989

Vitamin supplementation in pregnancy.

The aim of the study was to investigate the extent and determinants of vitamin supplementation in early pregnancy. Some 246 women were recruited in the antenatal clinics of a major teaching hospital and asked to complete a brief questionnaire relating to sources of advice and details of diet and vitamin supplementation during the index pregnancy. Further information was abstracted from routine antenatal records. A total of fifty-seven women (23%) took some form of vitamin supplement during the index pregnancy. Factors which affected supplementation included advice received from diverse sources and whether or not the women took iron supplements. Somewhat surprisingly, supplementation was not affected by age, social class or reproductive history.

Adolescent↗
PubMed1986

Contact dermatitis in hairdressers.

18 cases of hand dermatitis in hairdressers seen over a 5-year period are reviewed. The diagnoses in these patients are discussed with reference to other studies of hand dermatitis in hairdressers. Contact allergy due to paraphenylenediamine and related hair dyes was the presenting complaint in younger hairdressers, while formaldehyde allergy occurred in those who were older. The prognosis in the former group of workers with respect to continued employment in the trade tended to be poorer than the latter. Follow-up revealed that hand dermatitis often resulted in the worker not continuing to work in the hairdressing trade.

Adult↗
PubMed1985

Platelet behaviour in normal pregnancy, pregnancy complicated by essential hypertension and pregnancy-induced hypertension.

Platelet behaviour was studied throughout pregnancy in a group of women who remained normotensive and a group with essential hypertension (EHT). Women who developed pregnancy-induced hypertension (PIH) were also studied together with a group of non-pregnant female controls. We determined the sensitivity of platelets to arachidonic acid (AA) and determined the effects of dazoxiben, a thromboxane synthetase inhibitor, on AA-induced platelet behaviour. A marked increase in platelet reactivity was evident in all three groups throughout pregnancy; platelets became more sensitive to AA and less sensitive to the inhibitory effects of dazoxiben. The change was apparent as early as 16 weeks gestation. In normotensive pregnancy and in EHT platelet behaviour had returned to normal six weeks after delivery. Platelets from women who developed PIH were more sensitive to AA than those from the other pregnant women and platelet reactivity had not returned to normal six weeks after delivery. The results indicate that alterations in platelet behaviour may contribute to the vascular complications that are known to be associated with pregnancy and with PIH in particular.

Adenosine Diphosphate↗
PubMed1977

Predictive value of psychosocial profiles following aclte myocardial infarction.

Psychosocial profiles were done prospectively on 54 males and three females in addition to hemodynamics and non-invasive studies; the average age at admission was 44 years. The mean study time for 45 survivors was two years and three months and was seven months for 12 non-survivors. Thirty potential psychosocial problems were investigated during coronary care unit stay, and at three months, six months, and one year. Four problems previously shown to have prognostic significance were re-examined. Depression and pessimism occurred more frequently in non-survivors (α = .05). Patients with maladaptive family relationships post-admission were more likely to die (66 percent), than those with adaptive relationships (15 percent) (α = .05). Patients with poor social adaptation prior to admission had significantly more psychosocial problems during follow-up (α = .05). However, this group had no more deaths than the total population. The type and number of psychosocial problems of survivors and non-survivors of acute myocardial infarction have predictive prognostic value.

Acute Disease↗