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Biomedical subjects

G Foster

Publications and source records attributed to G Foster.

At least 109 records · Page 6Linked to original sources
PubMed1994

Determinants of the demographic impact of HIV-1 in sub-Saharan Africa: the effect of a shorter mean adult incubation period on trends in orphanhood.

Recent evidence suggests that the adult HIV-1 incubation period may be shorter in some sub-Saharan African populations than in Western populations. In this article we use mathematical-model-based simulations to show that, other things being equal, a shorter incubation period can result in smaller but more pronounced HIV-1 epidemics and faster, more acute, changes in demographic features, such as adult mortality, orphanhood and population structure. Empirical studies of orphanhood reveal similar patterns to those found in the simulations, but suggest that migration patterns and structural factors can give rise to greater concentrations of orphans in areas of relatively low HIV-1 prevalence.

Adolescent↗
PubMed1994

Influenza A outbreak in a nursing home: the value of early diagnosis and the use of amantadine hydrochloride.

An outbreak of respiratory tract infection due to influenza A virus occurred in February 1994 among residents of an 88-bed long term care facility in Toronto, Ontario. Eighteen confirmed and four probable cases of influenza were identified for an attack rate of 25%. Seventy-one per cent of the residents were known to have been immunized with trivalent influenza vaccine, but vaccine efficacy was determined to be only 32%. Influenza A viral antigen was rapidly detected by immunofluorescence microscopy of nasopharyngeal swabs, and amantadine hydrochloride was started in 76 residents within 48 h of recognizing the outbreak. Only two of the residents (3%) at risk became ill more than 48 h after amantadine was started. Amantadine was discontinued in four residents (5%) because of adverse effects (agitation, confusion, unsteady gait). In conclusion, rapid identification of the outbreak and prompt administration of amantadine hydrochloride prophylactically appears to be safe and effective in preventing further spread of influenza A.

Amantadine↗
PubMed1994

Improved gas chromatography/mass spectrometry analysis of barbiturates in urine using centrifuge-based solid-phase extraction, methylation, with d5-pentobarbital as internal standard.

Effective solid-phase extraction, derivatization, and GC/MS procedures are developed for the simultaneous determinations of butalbital, amobarbital, pentobarbital, and secobarbital, using a deuterated pentobarbital (d5-pentobarbital) as the internal standard. Buffered (pH 7) urine samples were extracted with Bond Elute Certify II cartridge. Iodomethane/tetramethylammonium hydroxide in dimethylsulfoxide was used for methylation, while a HP 5970 MSD equipped with a 13 m J & W DB-5 column (5% phenyl polysiloxane phase) and the Thru-Put Target software package were used for GC/MS analysis and data processing. This protocol was found to be superior, in both chromatographic performance characteristics and quantitation results, over a liquid-liquid extraction procedure without derivatization using hexobarbital as the internal standard. Extraction recoveries observed from control samples containing four barbiturates range from 80% to 90%. Good one-point calibration data are obtained for all four barbiturates in the 50 to 3200 ng/mL range. Interestingly, the one-point calibration data for pentobarbital are inferior to the other three barbiturates--due to interference from the internal standard (d5-pentobarbital). The calibration data of pentobarbital are best described by a hyperbolic curve regression model. Precision data (% CV) for GC/MS analysis, over-all procedure, and day-to-day performance are approximately 2.0%, 6.0%, and 8.0%, respectively. With the use of a 2 mL sample size, the attainable detection limit is approximately 20 ng/mL.

Amobarbital↗
PubMed1991

Effect of sulindac on the cough reflex of healthy subjects.

The effects of a single dose of sulindac 200 mg and placebo on the capsaicin-induced cough reflex were studied in a two-phase double-blind crossover study in 18 healthy subjects. Sulindac increased the threshold for capsaicin cough response significantly, but did not alter D5, peak response, or the total cough response when compared with placebo values.

Adult↗
PubMed1991

Prevalence of persistent cough during long-term enalapril treatment: controlled study versus nifedipine.

The prevalence and severity of cough during long-term enalapril treatment were examined by comparing a cohort of 136 hypertensive patients who started treatment with enalapril with consecutive age and sex-matched patients who commenced nifedipine therapy during the same period. Cough and other symptoms were assessed by a questionnaire designed to avoid bias towards reporting cough. After a mean of 27 months' treatment patients on enalapril had an excess of persistent cough (16 per cent, 95 per cent CI 7-25, p less than 0.01), voice change (14 per cent, 95 per cent CI 2-27, p less than 0.05) and sore throat (10 per cent, 95 per cent CI -0.1 to 20.3 per cent, p less than 0.01) when compared to nifedipine-treated patients. The cough was usually dry, moderate or severe, paroxysmal, and troublesome at night. Cough tended to be more common in women (23 per cent vs. 7.2 per cent), non-smokers, and at higher doses of enalapril, but was not related to age, duration of treatment, or chronic respiratory disease. Dry cough commonly persists as a troublesome side-effect during long-term enalapril treatment, and is often associated with voice change and sore throat.

Cough↗
PubMed1990

Three-generation reproduction study with dioctyl sodium sulfosuccinate in rats.

Groups of 30 male and 30 female rats (F0) were fed diets containing 0, 0.1, 0.5, or 1.0% dioctyl sodium sulfosuccinate (DSS) for 10 and 2 weeks, respectively. The F0 animals were then mated to produce an F1 litter. Groups of 30 male and 30 female F1 animals were fed the same dose levels for at least 10 weeks postweaning, and the breeding program was repeated to produce F2 animals. F3 animals were produced from F2 animals by the same procedure. The study was terminated with the F3 weanlings. Test diets were fed continuously throughout the study. All F0, F1, and F2 adults and F3 weanlings (one/sex/litter) were necropsied and given a macroscopic examination. There were no effects on reproductive function for parental animals of either sex during any of the three generations in this study. At the highest dose level (1.0% DSS), body weights were lower than those of controls during the premating phase for males in all three generations and for F1 and F2 females. Body weights for F1 and F2 males and females in the 0.5% dose group were also low during the premating phase. Pup weights on Lactation Day 0 were significantly lower than those of controls only for the high-dose group during the third generation. However, lower pup weight gains in the mid- and high-dose groups resulted in significantly lower pup weights on Day 21 for all three generations. Perinatal pup survival across three generations ranged from 96 to 100% for the control and treated groups. Pup survival ranged from 95 to 100% for controls, from 98 to 100% for low- and mid-dose groups, and from 91 to 99% for the high-dose group. There were no treatment-related mortality and antemortem or macroscopic observations. In summary, DSS administered in the diet to three successive generations of rats at levels of 0.5 and 1.0% caused a reduction in body weights for parental males in all generations and for F1 and F2 females. Pup weights at the 0.5 and 1.0% dose levels were also lower than those of the control in all three generations. However, the reduced body weights did not interfere with development of normal reproductive performance. DSS at levels up to 1.0% had no effects on the reproductive function of either sex in any generation and produced no treatment-related antemortem or macroscopic observations.

Animals↗
PubMed1989

Terrien's disease: clinical and ultrastructural studies, five case reports.

Terrien's disease occurs in middle-aged patients and is characterised by an insidious thinning of the cornea near the limbus. In most cases, this results in a peripheral ectasia associated with a severe degree of astigmatism. Inflammatory signs are rarely observed in this marginal corneal degeneration which is of unknown aetiology. Electron and light microscopic studies have been performed on five specimens from penetrating keratoplasties. Anatomical and clinical correlations showed the marked marginal degenerations of the corneal stroma to be consistently associated with lipid deposits, but without inflammatory cell infiltrate. These changes are in agreement with previous reported pathological descriptions of Terrien's disease.

Adult↗
PubMed1989

[Terrien's disease, apropos of 6 cases. Ultrastructural study].

Terrien's disease is characterized by slowly progressive thinning of the pre-limbal cornea in middle-aged patients. It usually leads to peripheral ectasia with marked astigmatism. It is rarely accompagnied by inflammation and its cause is unknown. Very few histopathologic examinations have been published, in particular those using electron microscopy We present detailed results concerning 6 patients in whom perforating keratoplasty permitted histopathologic and electron microscopic examination. Clinical and histological features reveal marked degeneration of the peripheral corneal stroma, with lipid accumulation unaccompagnied by significant inflammatory cellular infiltration in each case. Of interest is the association in one patient with keratoconus. The generally accepted pathogenic theories are fully discussed. The wealth of electron microscopic data provides a complete review of stromal degenerative changes.

Adult↗
PubMed1988

DARPP-32 as a marker for D-1 dopaminoceptive cells in the rat brain: prenatal development and presence in glial elements (tanycytes) in the basal hypothalamus.

The present article reviews some aspects of the localization of a dopamine- and cyclic AMP-regulated phosphoprotein, DARPP-32, which is assumed to be present in D-1 dopaminoceptive neurons. Its prenatal development starts at day 14 of gestation, is to a large extent complete at birth and seems to be independent of ingrowing dopamine-containing afferents. Rearrangements occur in certain areas, and in some systems DARPP-32 appears to be only transiently expressed. The presence of DARPP-32 in glial structures, the tanycytes, in the arcuate nucleus-median eminence complex in the mediobasal hypothalamus, has given further support to the hypothesis that dopamine, by controlling the shape of the tanycytes and the extension of their processes, can regulate LHRH release by a 'mechanical mechanism'. This hypothesis is now being examined in some experimental paradigms.

Animals↗
PubMed1987

Membranous nephropathy caused by mercury-containing skin lightening cream.

A 46 year old woman developed membranous nephropathy following the use of a mercury-containing skin lightening cream. This association has not been reported in the literature for over a decade and apparently never from this country. It is important that clinicians are aware of this usually eminently treatable cause of the nephrotic syndrome as it is likely to be missed unless specifically enquired for.

Basement Membrane↗
PubMed1986

[H3]-nitrendipine binding in non-neuronal cell cultures.

3H-Nitrendipine binding was observed in non-neuronal cells derived from fetal mouse spinal cultures grown in 10% fetal calf serum. One class of binding sites was observed with a Kd of 25 nM and a Bmax of 293 fmol/well (13 fmol/micrograms protein). These data suggest that low affinity binding sites for nitrendipine are present on non-neuronal cells.

Animals↗
PubMed1985

Reflux versus dysphagia: an objective evaluation of the Angelchik prosthesis.

Twenty-seven patients with proven longstanding gastro-oesophageal reflux underwent insertion of an Angelchik anti-reflux prosthesis. Preoperative studies included oesophageal manometry, endoscopy, acid reflux provocation test (ARPT) and 24 h oesophageal pH recording (24 h pH). Following operation mean lower oesophageal sphincter pressure was increased from 11 to 20 cmH2O. ARPT revealed significant pre-prandial reflux before operation in 16/24 compared with only 1/20 postoperatively; 24 h pH also showed an improvement in that 21/22 patients refluxed before operation compared with no significant reflux after. Dysphagia for solids of some degree was seen postoperatively in 26 patients and this was also demonstrated by delay in transit of a marsh-mallow swallow test. Severe dysphagia was seen in 4 patients and in 3 of these was related to rotation and displacement of the prosthesis necessitating removal.

Deglutition Disorders↗
PubMed1985

Anatomical and functional consequences of grafting mesencephalic neurons into a peripheral nerve "bridge" connected to the denervated striatum.

Adult rats with unilateral 6-hydroxydopamine lesions of the nigrostriatal pathway were tested for amphetamine-induced rotational asymmetry. In animals with functional deficits a fetal mesencephalic transplant was placed intracranially over the superior colliculus within the caudal end of a 2- to 3-cm-long heterologous sciatic nerve segment laid longitudinally on the skull. Two months later the rostral tip of the peripheral nerve graft was cut and inserted through a burr-hole into the denervated striatum. Animals were tested monthly for 5 months for rotational asymmetry and selected rats were sacrificed for histochemical examination. It was shown that the use of a peripheral nerve segment as a bridge between a distant neuronal transplant and a selected region of the adult host brain resulted in the growth of monoaminergic axons into the denervated striatum from the extracerebrally located grafted neurons. The nerve bridge was cut extracranially in rats whose rotational asymmetry had decreased towards normal levels to determine if this behaviour was dependent on axons reaching the striatum through the graft. Each of these animals exhibited an increase in rotational asymmetry one and three weeks after the transection of the nerve. These anatomical and functional observations suggest that the decrease in rotational asymmetry observed in these animals is related to the growth of long axons from the implanted mesencephalic neurons into the denervated host's striatum which traversed the entire peripheral nerve segment.

Animals↗