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Biomedical subjects

G Foster

Publications and source records attributed to G Foster.

At least 127 records · Page 7Linked to original sources
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↗
PubMed1983

Tuberous sclerosis in pregnancy.

Tuberous sclerosis is a relatively rare autosomal dominant disorder. The only report found in the English literature suggests that the pregnancy course for a woman with this disorder may be uneventful. The present authors report two cases indicating that these patients may be at increased risk in pregnancy.

Adolescent↗
PubMed1982

Electromyographic feedback: effects on voluntary muscle contractions in normal subjects.

To evaluate the efficacy and function of EMG feedback (FB) in muscle reeducation, voluntary muscle contractions with and without EMG FB were compared under controlled experimental conditions in normal human subjects (n=10). Each subject was instructed to produce 12 sustained, 30-second contractions of the left abductor hallucis muscle, 6 contractions in each of 2 sessions. For all subjects, EMG FB was provided in half of the trials, alternating with nonfeedback (NFB) trials. A ranking task was included to measure ability to discriminate contractions in the target muscle. EMG activity was significantly greater during muscle contractions attempted with EMG FB; this was due to increased motor unit recruitment early in the course of the trials, a positive response in normal subjects similar to that in paretic subjects in our previous study. Performance on the ranking task also indicated that subjects had little perceptual awareness of their muscle contractions. Our findings suggest that the positive response to EMG FB was due to the precise information it provided concerning small, poorly discriminated muscle contractions.

Biofeedback, Psychology↗
PubMed1978

Platelet monoamine oxidase in affective disorders.

Platelet monoamine oxidase (MAO) activity was determined with tryptamine as substrate for 61 drug-free patients who had a primary major depressive disorder and for 32 normal controls. Although there were no significant differences between the mean platelet MAO activity of 19 bipolar patients (4.94 nmoles/hr/mg of protein), 42 unipolar patients (4.97 nmoles), and the controls (4.78 nmoles), an analysis of variance indicated that the variance of the bipolar group was significantly greater than that of the other groups. This suggests that there may be subgroups of bipolar patients that differ in their platelet MAO activity but that appear to be distinct from the bipolar I vs bipolar II classification.

Adult↗
PubMed1977

Familial hemochromatosis. Physiologic studies in the precirrhotic stage of the disease.

We studied 12 members of a family with precirrhotic hemochromatosis to define the physiologic abnormalities in the asymptomatic phase of the disease. Six of 12 had increased iron stores; the mode of inheritance was consistent with an autosomal dominant trait. Serum ferritin levels were no more predictive of tissue iron levels than measurements of serum iron, transferrin saturation or chelatable iron excretion. In three affected family members intestinal iron content was normal. Liver proline hydroxylase activity and urinary hydroxyproline excretion did not correlate with tissue iron content, suggesting that, in addition to the possible role of tissue iron, hepatic fibrosis may involve other factors. "Borderline diabetes mellitus" was present in three affected family members, but extensive studies revealed that pituitary dysfunction is uncommon in early hemochromatosis. Increased levels of liver iron proved to be the most reliable marker for the disease.

Adolescent↗