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Biomedical subjects

S Rogers

Publications and source records attributed to S Rogers.

At least 163 records · Page 9Linked to original sources
PubMed1993

Measurement of plaque thickness and evaporative water loss in psoriasis with PUVA and dithranol treatment.

Pre-treatment plaque thickness determined the rate at which psoriasis responded to PUVA treatment, taking longer with thicker plaques. For dithranol, the rate of response to treatment was independent of pre-treatment plaque thickness. Plaques of psoriasis that showed the greatest evaporative water loss before treatment took longest to clear with PUVA. At the time of clinical clearing the water loss had returned to that of adjacent, uninvolved skin. With dithranol the evaporative water loss did not return to normal levels but remained considerably elevated when the plaque was clinically clear.

Anthralin↗
PubMed1993

Aluminum, iron, and zinc ions promote aggregation of physiological concentrations of beta-amyloid peptide.

A major pathological feature of Alzheimer's disease (AD) is the presence of a high density of amyloid plaques in the brain tissue of patients. The plaques are predominantly composed of human beta-amyloid peptide beta A4, a 40-mer whose neurotoxicity is related to its aggregation. Certain metals have been proposed as risk factors for AD, but the mechanism by which the metals may exert their effects is unclear. Radioiodinated human beta A4 has been used to assess the effects of various metals on the aggregation of the peptide in dilute solution (10(-10) M). In physiological buffers, 10(-3) M calcium, cobalt, copper, manganese, magnesium, sodium, or potassium had no effect on the rate of beta A4 aggregation. In sharp contrast, aluminum, iron, and zinc under the same conditions strongly promoted aggregation (rate enhancement of 100-1,000-fold). The aggregation of beta A4 induced by aluminum and iron is distinguishable from that induced by zinc in terms of rate, extent, pH and temperature dependence. These results suggest that high concentrations of certain metals may play a role in the pathogenesis of AD by promoting aggregation of beta A4.

Aluminum↗
PubMed1993

Developmental changes in renin gene expression in ovine kidney cortex.

The ontogeny of renin mRNA and renin content from renal cortical slices was studied in two groups of ovine fetuses at 92-94 days (0.64 gestation) and at 138-142 days (0.96 gestation), newborn lambs (0.4-2 days old), and adult sheep. Renal renin mRNA was identified by hybridization with a 32P-labeled full length rat renin cDNA. Renal renin content was measured as nanograms of angiotensin I generated per hour (active renin). There was a significant age effect on renin mRNA levels (F = 10.0, P < 0.001); values increase significantly between 0.64 and 0.95 g (P < 0.005), remain elevated in the newborns (P < 0.05), and subsequently decline in adulthood (P < 0.005). Likewise, renal renin content was significantly higher in late gestation fetuses and newborn lambs than in early gestation and adults (F = 8.3, P < 0.003). The renal renin content was strongly correlated with renin mRNA levels (R = 0.88, P < 0.0001). These results suggest that 1) the renin gene is developmentally regulated in the ovine kidney and 2) the renal content of active renin in basal conditions is regulated, at least in part, by events at the transcriptional level.

Animals↗
PubMed1993

Developmental and tissue-specific modulation of rat galactose-1-phosphate uridyltransferase steady state messenger RNA and specific activity levels.

To assess the role of genetic regulation as a modulating factor in the variability of rat tissue galactose-1-phosphate uridyltransferase (GALT) sp act, we have determined steady state GALT mRNA and sp act in rat liver during postnatal development. Steady state GALT mRNA levels increase from birth to d 5 and subsequently decrease toward adult levels. GALT sp act mirrors the mRNA pattern. A survey of steady state mRNA and GALT sp act of several adult rat tissues revealed marked tissue differences with a good correlation of the two parameters. Liver had the highest GALT mRNA and sp act; kidney, ovary, and heart had similar but lower mRNA and sp act; skeletal muscle and testes had the least GALT mRNA and enzyme sp act. These findings suggest that genetic regulation is important in the variable expression of GALT tissue sp act.

Aging↗
PubMed1993

Closed intramedullary biopsy for metastatic disease.

The surgical stabilization of metastatic fractures or impending fractures of long bones is recommended with the use of intramedullary nails. While the primary tumour has often been diagnosed previously, there are occasions when the fracture may be the presenting feature of malignancy. In both circumstances surgical oncologists require a histological diagnosis from around the fracture site so that any adjuvant therapy can be planned. Open biopsy is often employed although a closed method has been used by percutaneous puncture. Although intramedullary specimens have been obtained before with long bronchial type biopsy forceps, we report a simple and reliable technique for closed biopsy taken from intramedullary reamings at the time of fracture fixation. Lesions from both the femur and the humerus are amenable to this technique.

Aged↗
PubMed1993

Computerized task battery assessment of cognitive and performance effects of acute phenytoin motion sickness therapy.

Phenytoin was previously evaluated as an efficacious anti-motion sickness therapy in more than 24 individuals. To be effective, this short-term, novel therapy requires serum levels in the anticonvulsant range; therefore, it became imperative that the effects of phenytoin upon cognition and performance be quantified. Each subject was tested on a performance battery (Criterion Task Set) on two occasions while on either phenytoin treatment or placebo for subsequent statistical comparison. We evaluated 23 subjects with phenytoin serum levels ranging from 8.9 to 23.9 micrograms/L. While subjects with the higher serum levels consistently reported subjective side effects, there was no statistically significant degradation of sensory, cognitive, or performance capabilities compared to placebo.

Adult↗
PubMed1992

Oestrogen receptor and epidermal growth factor receptor expression in male breast carcinoma.

Male breast carcinomas are probably hormone-dependent, but receptor studies are few because this is a relatively rare tumour. We have studied 21 cases of male breast carcinoma immunohistochemically for oestrogen receptor (ER) and epidermal growth factor receptor (EGFR) expression employing the antibodies ER-ICA and 12E on formalin-fixed, paraffin-embedded material. In our series, 86 per cent of male breast cancers were ER-positive and 76 per cent were EGFR-positive. Male breast carcinomas do not exhibit the inverse correlation between ER and EGFR expression that characterizes female breast carcinomas. Owing to the limitations of a small series, we were unable to comment on the relationship between ER and EGFR expression and patient survival. However, the relatively high incidence of ER expression may provide a growth advantage for this tumour in a male environment characterized by low levels of oestrogen. In addition, high EGFR expression may also contribute to a poor prognosis independent of ER status.

Aged↗
PubMed1992

Maxillofacial injuries following steering wheel contact by drivers using seat belts.

Maxillofacial injuries are common sequelae in road traffic accidents. For the restrained driver, impact against the steering wheel is the most prevalent cause of injury. A sample of drivers restrained by seat belts with facial injury caused by the steering wheel was taken from data at the Accident Research Unit, University of Birmingham, UK. Two hundred and forty facial injuries occurred in 135 drivers, and these are described. Superficial contusion, laceration and nasal fractures predominated. There were 504 injuries at other body regions, and these were often caused by other vehicle components. These were, for 57% of drivers, no more serious than the facial injury caused by steering wheel contact. The role of steering wheel design in maxillofacial trauma is discussed and new solutions briefly reviewed.

Abbreviated Injury Scale↗
PubMed1992

Osteoporotic fractures: an unusual presentation of haemochromatosis.

The association of haemochromatosis and osteoporosis is well established, but it is unclear whether this is due to iron overload, hypogonadism, liver disease, or diabetes mellitus. We describe a young eugonadal male patient with osteoporotic fractures as a presenting feature of haemochromatosis, suggesting that factors other than hypogonadism contribute to osteoporosis.

Adult↗
PubMed1992

Measurement of child mortality in association with a multipurpose birth certificate programme in the Southern Highlands Province of Papua New Guinea.

A simple and inexpensive method for monitoring child mortality in association with birth registration was introduced into the Southern Highlands of Papua New Guinea. Eight thousand two hundred and one newborn infants were registered in 1988, approximately 77% of all children born in that year. The risk of death by age 2 was determined from reports given by the mother on the present status of a previously born child at the time of a recent delivery or during clinic registration of the current birth. This was 91 per 1000 for the province and corresponds to a risk of death by age 1 of 77/1000 by extrapolation using standard lifetables. This method was validated by comparison with a continuing demographic surveillance system covering 30,000 people in the western part of the province. The new birth certificate has been an incentive to increase supervised delivery rates and to generate a register that can be used to increase vaccination coverage.

Birth Certificates↗
PubMed1992

Patterns of methylation of the c-myc gene in human colorectal cancer progression.

Over-expression and abnormal intracellular location of the product of the oncogene c-myc in colonic dysplasia and neoplasia may be related to alterations in epigenetic mechanisms controlling the functioning of this gene. We have investigated the methylation patterns of the c-myc oncogene in human colorectal tissue representing various stages of dysplasia and neoplasia, including metastasis to liver, omentum and lymph node. Comparison of normal and neoplastic tissues from the same patient showed a decrease in methylation in a specific CCGG site in the third exon of c-myc through the progression from normal via dysplastic to neoplastic and metastatic tissue. Quantitative analysis revealed that in colonic adenocarcinomas an average of 66.1% and in metastatic deposits 83.1% of the myc gene DNA was hypomethylated at this site, as compared to a value of 9.2% in normal colonic mucosa. Adenomatous polyps showed an average value of 50.5% and hyperplastic polyps, 24.8%. The results suggest that partial hypomethylation of the c-myc gene third exon is associated with cell proliferation, and that deregulation of proliferation may be linked to the high levels of hypomethylation, presumably involving both copies of the gene in some cells, which occur at a relatively early stage in neoplastic progression.

Adenoma↗
PubMed1992

Intimal proliferation in an organ culture of human internal mammary artery.

OBJECTIVE: Intimal smooth muscle cell proliferation is an early feature of atherosclerosis. Its progression is difficult to monitor in humans and previous studies have mostly relied on necropsy material. The aim of this study was therefore to establish whether intimal proliferation occurred in an organ culture of human internal mammary artery. METHODS: Segments of freshly isolated internal mammary artery were maintained din standard tissue culture medium containing 30% calf serum for 14 d. Tissue viability (measured by ATP concentration) was maintained during processing and throughout the culture period [211(SEM 28) nmol ATP.g-1 wet weight on d 1 v 208(27) on d 14]. RESULTS: Histological transverse sections of cultured internal mammary artery showed the development of a neointima containing smooth muscle cells identified by immunocytochemistry for alpha actin. Pulse labelling of cultures with [3H]-thymidine showed proliferating cells predominantly in a neointimal layer with few dividing cells in the media. Cultured de-endothelialized vessels showed less neointimal thickening than cultured freshly isolated vessels [16(3) v 36(5) microns, p < 0.0025] as well as a reduced number of dividing cells per mm of neointimal length [3.1(0.6) v 5.5(1.1), p < 0.05]. CONCLUSIONS: Intimal proliferation occurred in organ culture of internal mammary artery. There is evidence for a factor derived from the endothelium, which may be important in the development of intimal proliferation.

Aged↗