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Biomedical subjects

R J Forsyth

Publications and source records attributed to R J Forsyth.

25 records · Page 2Linked to original sources
PubMed1993

Astrocytic glucose-6-phosphatase and the permeability of brain microsomes to glucose 6-phosphate.

Cells from primary rat astrocyte cultures express a 36.5 kDa protein that cross-reacts with polyclonal antibodies to the catalytic subunit of rat hepatic glucose-6-phosphatase on Western blotting. Glucose-6-phosphate-hydrolysing activity of the order of 10 nmol/min per mg of total cellular protein can be demonstrated in cell homogenates. This activity shows latency, and is localized to the microsomal fraction. Kinetic analysis shows a Km of 15 mM and a Vmax. of 30 nmol/min per mg of microsomal protein in disrupted microsomes. Approx. 40% of the total phosphohydrolase activity is specific glucose-6-phosphatase, as judged by sensitivity to exposure to pH 5 at 37 degrees C. Previous reports that the brain microsomal glucose-6-phosphatase system does not distinguish glucose 6-phosphate and mannose 6-phosphate are confirmed in astrocyte microsomes. However, we demonstrate significant phosphomannose isomerase activity in brain microsomes, allowing for ready interconversion between mannose 6-phosphate and glucose 6-phosphate (Vmax. 15 nmol/min per mg of microsomal protein; apparent Km < 1 mM; pH optimum 5-6 for the two-step conversion). This finding invalidates the past inference from the failure of brain microsomes to distinguish mannose 6-phosphate and glucose 6-phosphate that the cerebral glucose-6-phosphatase system lacks a 'glucose 6-phosphate translocase' [Fishman and Karnovsky (1986) J. Neurochem. 46, 371-378]. Furthermore, light-scattering experiments confirm that a proportion of whole brain microsomes is readily permeable to glucose 6-phosphate.

Animals↗
PubMed1991

D-Lactate associated encephalopathy in short bowel syndrome: management with long-term non-absorbable oral antimicrobials.

We describe a child with short bowel syndrome consequent upon jejunal atresia who developed recurrent episodes of D-Lactate associated encephalopathy. Three species of lactobacillus were isolated from the stool, each sensitive to neomycin. Oral neomycin administration resulted in rapid relief of all symptoms. Cessation of the neomycin on two occasions led to recurrent encephalopathic episodes which quickly resolved with recommencement of treatment. We discuss the possible aetiologies of this encephalopathy syndrome and the therapeutic options.

Journal Article↗
PubMed1991

Methaemoglobinaemia after ingestion of amyl nitrite.

We report a case of methaemoglobinaemia in a 2 year old girl after ingestion of an 'aphrodisiac' containing nitrite. The availability of these products, their poor labelling, and their intended presence in domestic bedrooms all serve to increase the hazard they pose to young children.

Accidents, Home↗
PubMed1986

Compatibility of imipenem-cilastatin sodium with commonly used intravenous solutions.

The stability of imipenem-cilastatin sodium (Primaxin, Merck Sharp & Dohme) in various intravenous fluids was determined after storage at 4 degrees C or 25 degrees C and after freezing. Samples of imipenem-cilastatin sodium were constituted with 100 mL of each of 17 i.v. fluids to concentrations of 2.5 mg/mL or 5.0 mg/mL of each drug component and stored in glass infusion bottles at constant room temperature (25 degrees C) or constant refrigerated temperature (4 degrees C). The concentration of each solution was determined immediately after constitution by a stability-indicating high-performance liquid chromatographic assay; the concentrations of both drugs were monitored in each i.v. fluid until the time that the concentration of either imipenem or cilastatin decreased to less than 90% of the initial concentration (t90). The exact value of t90 was determined for each solution by linear regression. The solutions were also assessed for changes in pH or color. Cilastatin sodium was more stable in all 17 i.v. fluids than imipenem. The stability of imipenem was dependent on the concentration of that drug in solution; solutions of imipenem 2.5 mg/mL were more stable than solutions of imipenem 5.0 mg/mL. The values of t90 for imipenem in solutions stored at 4 degrees C were greater than the values for solutions stored at 25 degrees C. Imipenem was most stable in 0.9% sodium chloride injection. The pH values of the solutions generally decreased during the study period.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

'Must try harder?': a family empowerment intervention for acquired brain injury.

This paper describes an intervention aimed at empowering parents of child survivors of acquired brain injury (ABI) in their interaction with teachers and other professionals involved in their child's education. The particular characteristics of the late morbidity of child ABI led to the design of an intervention in the form of a video and informational booklet that is the property of the family. Early response to the intervention has been extremely positive, although formal evaluation has been unexpectedly challenging.

Adolescent↗
PubMedDate not supplied

Visual impairment in children with acute nontraumatic coma.

PURPOSE: To determine the incidence and severity of visual impairment in children following acute nontraumatic coma. METHODS: An 18-month prospective epidemiologic study of acute nontraumatic coma was undertaken in the former Northern NHS Region of England. Children aged >1 month and <16 years were included in the study if they had a Glasgow Coma Score of < or = 12 for >6 hours or if they died within 6 hours of the onset of decreased levels of consciousness. For survivors, ophthalmologic assessments were performed 6 weeks and 12 months after presentation. RESULTS: Two hundred eighty-seven children were included in the study, of whom 127 died. Of the 137 examined survivors, 35 had visual abnormalities suspected by the examining neurologist during the ophthalmic assessment. Of these, visual impairment was confirmed in 10 children at the 6-week assessment by the pediatric ophthalmologist. At the 1 2-month assessment, visual impairment remained stable in 9 children and improved in 1. CONCLUSION: In this study, 6.6% of children surviving acute nontraumatic coma had visual impairment that persisted at the 12-month follow-up examination. Incidence of visual impairment in acute nontraumatic coma is 0.97 per 100,000 children per year.

Acute Disease↗