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Biomedical subjects

A G Davison

Publications and source records attributed to A G Davison.

At least 19 recordsLinked to original sources
PubMed1995

Hypokalaemic rhabdomyolysis: an unusual presentation of coeliac disease.

OBJECTIVE: To describe the clinical presentation and management of a patient with hypokalaemic rhabdomyolysis secondary to coeliac disease. DESIGN: Retrospective study. SETTING: Hospital based. PATIENT: A 60-year-old Caucasian man presenting with weakness caused by hypokalaemic rhabdomyolysis secondary to coeliac disease. INTERVENTIONS: Following the diagnosis by jejunal biopsy, the patient was treated with both intravenous and oral potassium supplements, and a gluten-free diet. OUTCOME MEASURES: Resolution of weakness and restitution of normal villous architecture following treatment. RESULTS: The patient's myopathy responded to the potassium supplements, his diarrhoea and histological changes resolved while on the gluten-free diet. CONCLUSION: Patients with coeliac disease may present with hypokalaemia in association with steatorrhoea. If potassium loss is rapid, rhabdomyolysis may occur. Coeliac disease should be considered a cause of malabsorption-induced hypokalaemic rhabdomyolysis.

Adult↗
PubMed1994

The use of multiple parameters to characterize cadmium-induced renal dysfunction resulting from occupational exposure.

Renal function has been examined in a group of 77 subjects occupationally exposed to cadmium fume and dust, together with a referent group of 103 age- and socioeconomically matched subjects. Fourteen biochemical parameters were measured on each subject. Three different ways of combining the information from all 14 tests were used to identify those subjects with renal dysfunction. These were first to count the number of parameters in which a subject recorded an abnormal test result. Second, the z value was computed for each parameter for each person by comparison with the mean and standard deviation of a derived normal population; these z scores were then summed. Lastly a multivariate distance measure, Mahalanobis D2, was determined for each subject from the distribution of normal subjects. The three approaches showed a considerable degree of agreement in identifying subjects with renal dysfunction, but they also displayed complementary strengths and weaknesses. The consensus of the three techniques was then taken to define truly dysfunctional subjects and each of the 14 parameters, and some combinations of pairs of parameters were tested as to their sensitivity and specificity. For this group of subjects, it was not possible to improve greatly on the use of retinol binding protein on its own. Were a second parameter to be chosen, it would be desirable to choose one reflecting the glomerular filtration rate, but the absence of a suitable sensitive biological monitoring parameter precludes a firm recommendation.

Blood Proteins↗
PubMed1994

Occupational asthma in salbutamol process workers.

Occupational asthma after exposure to salbutamol in the pharmaceutical industry has not been previously reported. The occurrence of occupational asthma is described in two pharmaceutical process workers who were likely to have inhaled doses appreciably in excess of the therapeutic dose range. The findings do not lead to an unequivocal conclusion on the mechanism of the asthma but it was probably a pharmacological consequence of high exposure.

Adult↗
PubMed1994

Osteochondroma of the rib: an unusual cause of haemothorax.

The case is described of a 36 year old woman who presented with a large left sided haemothorax. A thoracic computed tomographic (CT) scan suggested there was a bony outgrowth arising from the fourth rib. This was resected surgically and found to be an osteochondroma which was surrounded by blood clot. No definite site of bleeding was identified, but it is thought that the tumour may have traumatised the lung, the pericardiacophrenic artery, or the superior pulmonary vein, resulting in life threatening haemorrhage.

Adult↗
PubMed1994

Randomized trial comparing weekly versus 3-week chemotherapy in small-cell lung cancer: a Cancer Research Campaign trial.

PURPOSE: A randomized trial of chemotherapy, given on either a 1-week or a 3-week schedule, was performed in small-cell lung cancer (SCLC) patients. The aim was to determine if weekly scheduling produced survival superior to conventional treatment. PATIENTS AND METHODS: Four hundred thirty-eight patients with SCLC with either limited disease (LD; 276 patients) or good-prognosis extensive disease (ED; 162 patients) were randomized. Weekly chemotherapy was 12 alternating cycles of ifosfamide/doxorubicin and cis-platin/etoposide (PE), while 3-week treatment was six alternating cycles of cyclophosphamide/doxorubicin/vincristine (CAV) and PE. Thoracic irradiation was administered 3 weeks after completion of chemotherapy to LD patients who attained a complete response (CR) or partial response (PR). Patients were well matched for clinical characteristics and prognostic factors. RESULTS: Overall response was the same in both arms: 82.3% (39.4% CR) with weekly and 81.1% (36.9% CR) with 3-week treatment. The median survival (MS) durations were 10.8 and 10.6 months for weekly and 3-week chemotherapy, respectively. The 2-year survival rates were 11.8% and 11.7% in the weekly and 3-week arms, respectively. Received dose-intensity (DI) was 73.9% of projected for weekly treatment and 92.7% for 3-week treatment. Hematologic toxicity was the major dose-limiting toxicity for the weekly treatment. CONCLUSION: This trial excludes at 90% power a benefit of greater than 10% for 2-year survival for weekly treatment. The received DI was reduced to a greater extent with weekly treatment, mainly due to hematologic toxicity.

Adult↗
PubMed1992

Evidence for phosphatidylinositol hydrolysis in pancreatic islets stimulated with carbamoylcholine. Kinetic analysis of inositol polyphosphate metabolism.

Anion-exchange h.p.l.c. was used initially to analyse the products formed after addition of either [3H]Ins(1,3,4,5)P4 or [3H]Ins(1,4,5)P3 to homogenates of pancreatic islets. Metabolic routes similar to those of other tissues were established: dephosphorylation of Ins(1,4,5)P3 to Ins(1,4)P2 and then Ins4P; and sequential degradation of Ins(1,3,4,5)P4 to Ins(1,3,4)P3, Ins(3,4)P2 and Ins(3 or 1)P. In addition, there was a limited conversion of Ins(1,3,4)P3 into Ins(1,3)P2. After stimulation of [3H]inositol-prelabelled islets with the muscarinic-receptor agonist carbamoylcholine (carbachol), there was a rapid (10 s) increase in Ins(1,4,5)P3, Ins(1,3,4)P3, Ins(1,4)P2 and Ins4P. In the presence of 10 mM-LiCl, Ins1P was also significantly increased (P less than 0.05) by 5 s, before any increase in Ins4P (10 s), Ins(1,3)P2 (60 s) or Ins(3,4)P2. When carbachol was displaced with atropine, after 1 h pre-stimulation, the maximal decreases in Ins(1,4,5)P3 and Ins1P from the stimulated steady state (5 s) clearly preceded those of the other metabolites. These declines were used to calculate the turnover times and rate of metabolic flux through the various inositol phosphates. These experiments confirmed the relatively minor importance of the Ins(1,3)P2 pathway (less than 10% of the total flux) and demonstrated that Ins(1,4,5)P3 removal was evenly distributed through the Ins(1,4)P2 and Ins(1,3,4,5)P4 routes. They also established that flux through Ins1P was 8-fold greater than that through Ins(1,4,5)P3, indicating that the former could not have been derived from PtdInsP2 hydrolysis. Similarly, in islets pretreated with neomycin, which binds to PtdInsP2 with greater affinity than to PtdIns, the increase in Ins1P caused by 1 min stimulation with carbachol was not affected, despite virtual abolition of the increase in Ins4P, and an overall inhibition of PtdInsP2 hydrolysis by 67%. The results indicate that, in addition to PtdInsP2 breakdown, carbachol also promotes a rapid PtdIns hydrolysis which becomes increasingly predominant with prolonged stimulation.

Animals↗
PubMed1989

Effect of phorbol esters on the distribution and total activity of protein kinase C in the perfused rat heart.

1. The perfused rat heart was treated with the tumour-promoter and protein kinase C activator, phorbol 12-myristate 13-acetate and the distribution of protein kinase C activity between cytosolic and particulate fractions determined. 2. Phorbol ester treatment led to a rapid loss of protein kinase C activity from the cytosol (t0.5 = 2 min) with a corresponding translocation into the particulate fraction. Translocated protein kinase C activity was tightly bound to the particulate fraction, could only be extracted with buffers containing 2% Triton X-100 and could therefore be misinterpreted as being down-regulated. 3. Claims of rapid down-regulation of protein kinase C activity by phorbol esters need to be supported by rigorous procedures for extraction of the particulate material.

Animals↗
PubMed1989

Consequences of occupational asthma.

Seventy-nine patients attending hospital for follow-up of occupational asthma were interviewed, on average 6 years after asthma developed. Although 90% thought their symptoms had improved, 10% had required a hospital admission (apart from for investigation), 72% still took medication and most reported symptoms in the last 3 months. One-third were currently unemployed and 40-73% reported limitation in everyday activities, such as housework or shopping. Symptoms on waking were used as an index of troublesome asthma. Those 31 in whom this occurred at least once a week reported limitation in everyday activities significantly more commonly than others. This relation was more marked in men than women. Limitation in everyday activities was, however, more frequently reported by women than men, who were also more likely than men to be unemployed, suggesting that factors other than impairment of function also contribute to handicap in occupational asthma.

Activities of Daily Living↗
PubMed1989

Pseudo-occupational asthma.

A case is reported in which a pattern of work related asthma in a record of peak expiratory flow was artefactual. The patient had pronounced morning dips, which she recorded on working days, when she made the first recording at 0700 h, but not on holiday, when she stayed in bed longer. The case emphasises the need for clear instructions to patients about peak flow records.

Asthma↗
PubMed1988

Cadmium fume inhalation and emphysema.

Lung function and chest radiographs of 101 men who had worked for 1 or more years manufacturing copper-cadmium alloy were compared with those of a referent group matched for age, sex, and employment status. Cigarette consumption was similar in the two groups. The cadmium workers had an excess of abnormalities of lung function and of radiographic changes consistent with emphysema. Classification of the cadmium workers by exposure categories based on either estimated cumulative cadmium exposure or liver cadmium measured by neutron activation analysis showed that abnormalities of lung function were greatest in those with the highest cumulative cadmium exposure or liver cadmium. The difference in the transfer coefficient (KCO) between cadmium workers and referents increased linearly with increasing cumulative exposure without evidence for a threshold. The estimated mean decrement in KCO for a cadmium worker employed 5 or more years with a cumulative exposure of 2000 yr.microgram.m-3 (exposure to the current UK control limit of 50 micrograms.m-3 for a working lifetime of 40 yr) lies between 0.05 and 0.3 mmol.min-1.kPa-1.l-1 (95% confidence interval). This decrement is consistent with the functional and radiological changes of emphysema observed in this group of workers.

Aged↗
PubMed1988

Relations between liver cadmium, cumulative exposure, and renal function in cadmium alloy workers.

Detailed biochemical investigations of renal function were made on 75 male workers exposed to cadmium and an equal number of referents matched for age, sex, and employment status. The exposed group consisted of current and retired workers who had been employed in the manufacture of copper-cadmium alloy at a single factory in the United Kingdom for periods of up to 39 years and for whom cumulative cadmium exposure indices could be calculated. In vivo measurements of liver and kidney cadmium burden were made on exposed and referent workers using a transportable neutron activation analysis facility. Significant increases in the urinary excretion of albumin, retinol binding protein, beta 2 microglobulin, N-acetylglucosaminidase (NAG), alkaline phosphatase, gamma-glutamyl transferase and significant decreases in the renal reabsorption of calcium, urate, and phosphate were found in the exposed group compared with the referent group. Measures of glomerular filtration rate (GFR) (creatinine clearance, serum creatinine, and beta 2 microglobulin) indicated a reduction in GFR in the exposed population. Many of these tubular and glomerular function indicators were significantly correlated with both cumulative exposure index and liver cadmium burden. Using cumulative exposure index and liver cadmium as estimates of dose, a two phase linear regression model was applied to identify an inflection point signifying a threshold level above which changes in renal function occur. Many biochemical variables fitted this model; urinary total protein, retinol binding protein, albumin, and beta 2 microglobulin gave similar inflection points at cumulative exposure levels of about 1100 y.micrograms/m3 whereas changes in the tubular reabsorption of urate and phosphate occurred at higher cumulative exposure indices. Measures of GFR, although fitting the threshold model did not give well defined inflection points. Fewer variables fitted the two phase model using liver cadmium; those that did gave threshold levels in the range 20.3-55.1 ppm. When cadmium workers with cumulative exposure indices of less than 1100 y.micrograms/m3 were compared with their respective referents only serum beta 2 microglobulin and urinary NAG were significantly increased in the exposed group and these differences were not related to the degree of cadmium exposure.(ABSTRACT TRUNCATED AT 400 WORDS)

Alloys↗
PubMed1987

Meptazinol overdose producing near fatal respiratory depression.

Meptazinol is one of the new powerful opioid analgesic agents, and an oral formulation has recently been marketed. Clinically significant respiratory depression is said to be absent and no overdoses from meptazinol have been reported in the literature. We report a patient who had a respiratory arrest following an overdose of meptazinol.

Azepines↗
PubMed1986

Number of patients required in lung function studies.

Tables are presented showing estimates of the number of subjects which is required to give an 80% or 90% chance of detecting various differences in forced expiratory volume in one second, forced vital capacity, total lung capacity, transfer factor, and residual volume between the mean of two groups by means of Student's t test.

Humans↗
PubMed1985

Occupational asthma due to methyl methacrylate and cyanoacrylates.

Five patients had asthma provoked by cyanoacrylates and one by methyl methacrylate, possibly because of the development of a specific hypersensitivity response. Acrylates have wide domestic as well as industrial uses, and inhalation of vapour emitted during their use can cause asthma.

Adult↗
PubMed1984

Peak flow rate records in surveys: reproducibility of observers' reports.

Records of peak expiratory flow rate (PEFR), commonly used in hospital in the management of asthma, have not been evaluated as a method of identifying cases of asthma in population surveys. Four observers were asked to report on whether asthma was present or absent in 61 graphs of PEFR recorded two hourly for four weeks during surveys of working population. Agreement within individual observers was measured using a subset of 29 graphs which had been copied and distributed at random among the set of 61; agreement was good, from 90% in one observer to 100% in two. Agreement between observers was measured on the basis of all 61 graphs. Agreement occurred between all four observers in 69% of graphs, between at least three out of four in 97%, and, when pairs of observers were examined, between 72% and 93% of graphs. Graphs assessed as showing asthma demonstrated more within day PEFR variability (expressed as the number of days in which the difference between maximum and minimum readings was at least 15%) than graphs assessed as not showing asthma. Some graphs with little within day variability were assessed as showing asthma, apparently because they demonstrated between day PEFR variability.

Asthma↗