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Biomedical subjects

A J Pollard

Publications and source records attributed to A J Pollard.

64 records · Page 4Linked to original sources
PubMed1992

Altitude-dependent changes of directional hearing in mountaineers.

This study demonstrates apparent deterioration in the ability to localize sound associated with acute exposure to high altitude in ten subjects on three mountaineering expeditions. Furthermore, the auditory localization errors improved to sea level values after a period of acclimatization. Occurring at altitudes where overt neurological symptoms are not usually seen, impairment of sensory perception may explain the increase in accidental deaths associated with altitude exposure due to disorientation and misjudgment but before hypoxia is evident.

Acclimatization↗
PubMed1990

Traditional birth attendants in the Gambia.

In developing countries traditional birth attendants help at 60-70% of births, despite rapidly expanding "Western-style" health services. Recognising the potential of this established service, the World Health Organisation has been involved in a programme of training and supervision of traditional birth attendants (TBAs) in developing countries since 1973. An evaluation of training programmes in 1986 showed considerable success with improved antenatal care, decreased neonatal tetanus, increased recognition and transfer to hospital of complications of pregnancy and delivery and encouraging improvements in many other indices of improved management. This short paper describes the health services available in a developing country, The Gambia, in West Africa, and reports an interview with a trained traditional birth attendant in a rural area of the country.

Gambia↗
PubMed1988

Neonatal hepatitis induced by alpha 1-antitrypsin: a transgenic mouse model.

Transgenic mouse lineages were established that carry the normal (M) or mutant (Z) alleles of the human alpha 1-antitrypsin (alpha 1-Pi) gene. All of the alpha 1-Pi transgenic mice expressed the human protein in the liver, cartilage, gut, kidneys, lymphoid macrophages, and thymus. The human M-allele protein was secreted normally into the serum. However, the human Z-allele protein accumulated in several cell types, but particularly in hepatocytes, and was found in serum in tenfold lower concentrations than the M-allele protein. Mice in one lineage carrying the mutant Z allele expressed high levels of human alpha 1-Pi RNA and displayed significant runting (50% of normal weight) in the neonatal period. This lineage was found to have alpha 1-Pi-induced liver pathology in the neonatal period, concomitant with the accumulation of human Z protein in diastase-resistant cytoplasmic globules that could be revealed in the Periodic acid-Schiff reaction (PAS). The phenotype of mice in the strain expressing high levels of the Z allele is remarkably similar to human neonatal hepatitis, and this strain may prove to be a useful animal model for studying this disease.

Alleles↗
PubMed1988

Nephroptosis: a cause of renal pain and a potential cause of inaccurate split renal function determination.

We present 3 cases of nephroptosis encountered in young females over a 6-month period which posed diagnostic difficulties and gave inaccurate split renal function determinations until the true situation was disclosed. A syndrome is described of clinical presentation with right upper quadrant pain, erect hippuran renography showing an apparently small right kidney and reduced function but with normal time to peak and elimination phase on the curve (the "miniaturised" renogram) and erect and supine DMSA scintigraphy which confirms the diagnosis of abnormal renal mobility. Guidelines are suggested by which nephroptosis can be recognised and assessed in urological and nuclear medicine practice.

Adult↗
PubMed1986

Accuracy and reproducibility of a new contrast clearance method for the determination of glomerular filtration rate.

A new method for determining the glomerular filtration rate was analysed prospectively. The method uses an x ray fluorescence technique to measure disappearance from the plasma of injected non-ionic iodinated contrast media. Eighty seven patients were studied. Fifty four had an intravenous dose of 100 ml iohexol (Omnipaque) and 33 had 50 ml iohexol. Clearances of chromium-51 labelled edetic acid (51Cr-EDTA) were measured simultaneously. In the patients given 100 ml iohexol there was excellent correlation with 51Cr-EDTA clearance (r = 0.90). The correlation using 50 ml iohexol was also good (r = 0.85). Correlation between creatinine clearance and clearance of 51Cr-EDTA in 33 patients was less satisfactory (r = 0.69). There were no adverse reactions to the contrast media. The equipment used for measuring contrast clearance was robust and simple to operate. Freezing plasma samples in 10 studies and re-examining them weekly for six weeks showed no significant variation in results; hence reproducibility was good. This new and accurate method for determining the glomerular filtration rate merits further study and might find a useful place in routine clinical practice.

Adolescent↗
PubMedDate not supplied

Gene array technology to determine host responses to Salmonella.

Gene expression array technology is a powerful new tool that has already been used to expand our understanding of host-pathogen interactions. There has been a rapid increase in published reports describing use of this approach to profile host responses to pathogenic bacteria and viruses. The large number of array studies currently in progress coupled with increasing accessibility of this new technology promises a plethora of gene expression data on host response to infection in the near future. Recent insights into macrophage and epithelial cell responses to Salmonella infection garnered from array studies are outlined and used as a basis to discuss various future research directions using gene arrays that will advance the field of cellular microbiology. There is an exciting potential for the gene expression data generated in such studies to provide insights into host physiology, the pathophysiology of disease and novel therapeutics.

Animals↗