Biomedical subjects
J Harrison
Publications and source records attributed to J Harrison.
von Willebrand factor multimer analysis using a sensitive peroxidase staining method.
A peroxidase staining method for von Willebrand factor (vWF) multimer analysis was modified for comparison with an autoradiographic method. This method consists of SDS-agarose electrophoresis followed by blotting to a nitrocellulose membrane and a sensitive peroxidase staining method. The resolution of vWF multimers on the nitrocellulose membrane is comparable to that on the conventional autoradiography. Results can be obtained in 3 days. This nonradioisotopic method will be useful for the determination of the type of von Willebrand's disease in clinical laboratories.
A request for the 'morning-after' pill.
A request for post-coital contraception may be the first consultation by a young girl for contraceptive advice. The problem may be used as an opportunity to discuss other relevant issues such as AIDS. The case will need sympathetic and sensitive handling and demands consideration of confidentiality, especially in Samantha's case as she is only 15.
Art-related health hazards: artists should be put in picture.
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Short-term toxicity of nine industrial chemicals.
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Prevention and rehabilitation of osteoporosis program: exercise and osteoporosis.
Osteoporosis is a common crippling bone disease affecting post-menopausal and elderly women. It results in fractures, spinal deformity and chronic pain leading to decreased mobility and functional disability. A preventive program in Toronto, described in this article, aims to prevent bone loss and maximise the functional capacity of osteoporotic patients through a program with educational, social and exercise components. Evaluation of the program, also reported here, showed that 80 per cent of patients complied with the requirements of the exercise program and that those who exercised reported improvement in general well being, stamina, mobility and pain tolerance. The exercise group also showed a significant improvement in VO 2 max (p less than 0.001) and bone mass (p less than 0.02) after one year of exercise. None of the patients developed fracture as a direct result of the exercise. The exercise prescribed for osteoporosis is safe and beneficial. The program is a social success.
Randomised double blind controlled trial of cyclosporin in multiple sclerosis.
In a 2 year double blind controlled trial of cyclosporin against placebo in multiple sclerosis conducted at two centres there was a beneficial effect of the therapy upon the progression of the disease, relapse rate and relapse severity at one of the centres where the patients received a mean dose of 7.2 mg/kg/day. This beneficial effect was not seen in the other centre where a lower dose (mean 5 mg/kg/day) was given. Reduction in clinical progression was accompanied by decreased IgG synthesis in the central nervous system. Side effects included hypertension, renal insufficiency and anaemia and were of such severity to preclude the use of cyclosporin in a high enough dose to alter the course of the disease.
Hormonal regulation of collagen gene expression in osteoblastic cell-overview and new findings.
Type I collagen synthesis in osteoblasts is regulated by a variety of systemic hormones, growth factors and locally produced factors. With the use of cDNA probes and hybridization analysis, it appears that many of these agents alter collagen synthesis by a pretranslational mechanism.
Posterior cortical atrophy.
Two patients had a steadily progressive disorder of higher cortical function dominated by the early development of cortical visual deficits. In one, a right visual inattention progressed over a period of 2 years to a complete right homonymous hemianopia and relative left inferior quadrantanopia. In the second case, blind in the left eye for unrelated reasons, a temporal field loss was noted at presentation in the right eye, with the subsequent development of field loss in the inferior nasal quadrant on that side. Features of Balint's syndrome developed in both patients, with sticky fixation, ocular dysmetria and simultanagnosia. Prominent associated features were progressive dysmnesia, dyscalculia, ideomotor apraxia and spatial disorientation. Abstract reasoning, speech function and insight were all well preserved. MRI and CT scans revealed no focal abnormalities. These cases are similar to the 5 recently described by Benson et al. The pathological basis is unknown but may be an atypical form of Alzheimer's disease.
Analysis of the amino acid and sugar composition of streptococcal cell walls by gas chromatography-mass spectrometry.
A procedure for determining the amino acid and sugar composition of streptococcal peptidoglycan-polysaccharide complexes by capillary gas chromatography-mass spectrometry (GC-MS) was established. Amino acids are analysed as butyl heptafluorobutyl derivatives and sugars as alditol acetates. These two different groups of compounds are derivatized independently but chromatography in both cases utilizes the same OV-1701 fused-silica capillary column which simplifies GC-MS analysis. The butyl heptafluorobutyl procedure incorporates new pre- and post-derivatization clean-up steps. Additionally, selected-ion monitoring MS allows amino acids to be readily analysed without interference from background noise.
Adrenocorticotrophin (ACTH) deficiency undetected by standard dynamic tests of the hypothalamic-pituitary-adrenal axis.
Six patients (four females, two males; aged 18-65 years), previously treated by external pituitary irradiation (2000-4000 cGY in 8-15 fractions over 10-20 days) for pituitary tumours, presented with the symptoms of excessive and inappropriate tiredness suggestive of ACTH deficiency, despite a normal peak cortisol response to an insulin tolerance test (four cases) or to a glucagon stimulation test (two cases). These six patients were found to have significantly lower mean 24 h urinary free cortisol levels (100 +/- 40 nmol; mean +/- SD) compared with the mean value of 31 normal controls (210 +/- 70.8 nmol; P less than 0.01). In addition serum cortisol profiles based on a series of four timed samples between 0900-2300 h were subnormal (mean 130 nmol/l) in comparison with profiles obtained from 12 normal controls (mean 270 nmol/l) (P less than 0.001). Glucocorticoid replacement therapy promptly abolished their symptoms. These results suggest that a discordance between ACTH secretion under basal circumstances and ACTH response to pharmacological tests may exist in patients with ACTH deficiency. We speculate that defective endogenous corticotrophin-releasing hormone (CRF) secretion, due to radiation-induced damage at hypothalamic level, is one cause of this phenomenon.
Blood glucose, lactate, pyruvate, glycerol, 3-hydroxybutyrate and acetoacetate measurements in man using a centrifugal analyser with a fluorimetric attachment.
Methods are described for the analysis of glucose, lactate, pyruvate, alanine, glycerol, 3-hydroxybutyrate and acetoacetate in perchloric acid extracts of human blood, using the Cobas Bio centrifugal analyser fitted with a fluorimetric attachment. Intra-assay and inter-assay coefficients of variation ranged from 1.9 to 7.9% and from 1.0 to 7.2% respectively. Correlation coefficients ranged from 0.96 to 0.99 against established continuous-flow and manual spectrophotometric methods. All seven metabolites can be measured using a single perchloric acid extract of 20 microliter of blood. The versatility of the assays is such that as little as 100 pmol pyruvate, 3-hydroxybutyrate or as much as 15 nmol glucose can be measured in the same 20 microliter extract.
Taking life one night at a time. "Sex addicts" seek help.
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Alzheimer's disease and related disorders support society.
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Operative choledochoscopy via the cystic duct: a pilot study with an ultra-thin fibreoptic endoscope.
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Electrohydraulic lithotripsy of gall stones--in vitro and animal studies.
Electrohydraulic lithotripsy of human gall stones was investigated in vitro in a bath of saline and in a saline perfused bile duct. The technique was effective--only two stones could not be shattered. Electrohydraulic lithotripsy power requirement correlated with mechanical strength of stones, but not with biochemical composition. A trend toward higher power requirement was recorded with larger stones and stones over 2 cm in diameter could not be fragmented. Safety studies indicated that electrohydraulic lithotripsy was safe, provided the probe tip was not in contact with the bile duct wall. In vivo studies did not show any late effects after 10 days. Electrohydraulic lithotripsy is likely to be useful in the management of biliary calculi.