Biomedical subjects

P McRae

Publications and source records attributed to P McRae.

4 recordsLinked to original sources

PubMed2004

Estrogen mediates sex differences in stress-induced prefrontal cortex dysfunction.

Many anxiety disorders, as well as major depressive disorder (MDD), are at least twice as prevalent in women as in men, but the neurobiological basis of this discrepancy has not been well studied. MDD is often precipitated by exposure to uncontrollable stress, and is frequently characterized by abnormal or disrupted prefrontal cortex (PFC) function. In animals, exposure to stress has been shown to cause PFC dysfunction, but sex differences in this effect have not been investigated. The present study tested male and female rats on a PFC-dependent working memory task after administration of FG7142, a benzodiazepine inverse agonist that activates stress systems in the brain. Female rats were impaired by lower doses than males during proestrus (high estrogen), but not during estrus (low estrogen). Similarly, ovariectomized females showed increased stress sensitivity only after estrogen replacement. These results suggest that estrogen amplifies the stress response in PFC, which may increase susceptibility to stress-related disorders.

Animals↗

PubMed1997

Genetic population structure of the Greater Bilby Macrotis lagotis, a marsupial in decline.

The Greater Bilby has shown a rapid decline in range during this century and now occupies only a small isolated area in south-western Queensland (QLD) and a larger, but mostly low-density area in the north-western deserts of the Northern Territory (NT) and Western Australia (WA). We have examined variation in the control region of mitochondrial DNA (mtDNA) and at nine microsatellite loci in order to investigate the extent of current and historical subdivision across the species range, and to provide a preliminary assessment of genetic structuring and mating system on a finer scale within the QLD population. Both mtDNA and microsatellite loci had substantial variation within and among populations, with mtDNA divergence being greater between QLD and NT than between NT and WA. The QLD population had two unique and divergent mtDNA lineages, but there was no evidence for strong phylogeographical structure across the range. The available evidence suggests that the bilby should be considered as a single Evolutionarily Significant Unit consisting of multiple Management Units. Augmentation of the remnant QLD population from the NT does not appear necessary at this stage, at least not on genetic grounds. Finer-scale analysis of microsatellite variation for two QLD colonies revealed a deficiency of heterozygotes and significantly greater relatedness within than between colonies. However, structuring was observed only for males; relatedness values for females did not depart from those expected under panmixia. Parentage exclusion analysis for one colony allowed the construction of a partial pedigree which indicated strong polygyny, with one male fathering all but one of the eight offspring assigned. The extent to which fine-scale genetic structuring and differences between sexes is due to sex-biased dispersal vs. effects of mating system remain to be determined.

Animals↗

PubMed1992

Central venous thrombophlebitis diagnosed by computerized tomography scanning.

A case is described in which computerized tomography scanning aided in a prompt diagnosis and assessment of an intravenous catheter-induced septic thrombus. Computerized tomography scanning detected gas bubbles within the thrombus, which extended from the right subclavian vein into the superior vena cava, and retrograde propagation of the thrombus into the right internal jugular vein. Computerized tomography scanning also helped in the assessment of the amount of deep tissue swelling present and the competence of the upper respiratory tract.

Adult↗

PubMed1987

Clam enterocystoplasty in the neuropathic bladder.

Clam enterocystoplasty has proved to be the most effective treatment for severe detrusor instability resistant to conservative treatment (Bramble, 1982; Mundy and Stephenson, 1985). More recently it has become the procedure of choice in patients with neuropathic bladders with hyper-reflexia or severely impaired compliance, provided that the bladder is of reasonable size and that gross fibrosis and/or diverticular formation of the bladder wall has not occurred. Fifty-nine patients have undergone the clam procedure as part or all of their reconstruction in the past 4 years. Although uncontrolled incontinence was the commonest indication, impaired renal function was the indication in 14 patients and need for undiversion in seven. Currently all but four are voiding satisfactorily or are on intermittent self-catheterisation, though six have significant stress incontinence. The clam procedure is easier, quicker and as satisfactory as substitution cystoplasty in selected cases.

Adolescent↗