Biomedical subjects
J Symonds
Publications and source records attributed to J Symonds.
A simple method of nitric oxide delivery and analysis.
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Low activity sn-glycerol-3-phosphate dehydrogenase variants in natural populations of Drosophila melanogaster.
Eleven Australian natural populations of Drosophila melanogaster were screened by electrophoresis for evidence of null and/or low activity variants at the Gdph locus. Of 5018 alleles investigated, 57 had markedly lower GDPH activity, as judged by their heterozygous phenotypes, than control alleles. GPDH assays of 13 of these variant alleles showed that whilst they were heterogeneous in their properties and included electrophoretic variants and two categories of low-activity variant, there were no true null alleles. The most common low-activity variants exhibited dominance for GPDH activity in heterozygotes with normal alleles, and were shown to share this property with an allele previously isolated from a London (UK) population (Langley et al., 1981).
Haemorrhagic colitis and Escherichia coli O157--a pathogen unmasked.
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The penetration of ofloxacin into bronchial secretions.
Penetration of ofloxacin into bronchial secretions following a single 400 mg oral dose was studied in 52 patients. Bronchial secretions were aspirated at bronchoscopy between one and 24 h after dosing and blood was collected at the same time. Mean bronchial secretion concentrations between 2 and 2.6 mg/l were measured in 36 patients between 1 and 6 h but there was considerable individual variation in both serum and bronchial aspirate concentrations. Concentrations declined slowly between 9 and 24 h to a mean value of 0.4 mg/l at 24 h. Correlation between serum and sputum concentrations of ofloxacin was fairly good despite marked deviation in some individuals. The ratios of the concentration in bronchial secretion to serum were remarkably constant at 1 to 6 h, varying between 0.96 during the third and fourth hours and 0.81 in the sixth hour. The results suggest that ofloxacin in a 400 mg oral dose is likely to achieve therapeutic activity against respiratory pathogens including Streptococcus pneumoniae, with sustained activity against more sensitive organisms for up to 24 h.
The psychology of spontaneous abortion.
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Penetration of antibiotics into the respiratory tract.
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Penetration of ofloxacin into bronchial secretions.
The penetration of ofloxacin into bronchial secretions was evaluated in 16 patients after administration of a single oral dose of ofloxacin 400mg. Bronchial secretions were aspirated at bronchoscopy after 1 to 6 hours and serum was collected simultaneously. Ofloxacin concentrations were measured by a microbiological assay method. Considerable individual variations in serum and bronchial aspirate concentrations were recorded: bronchial aspirate concentrations varied between 1.1 mg/L and 4.5 mg/L but exceeded 1.5 mg/L in 14 of 16 patients between 1 and 6 hours. The ratio between simultaneous mean bronchial aspirate and serum concentrations ranged between 0.53 in the second hour and 0.92 in the fourth hour. It is likely that inhibitory activity will be sustained over at least 6 hours against most potential respiratory pathogens including Haemophilus influenzae, Branhamella catarrhalis, Gram-negative bacilli, Staphylococcus aureus, Legionella pneumophila and Mycoplasma pneumoniae. Streptococcus pneumoniae and Pseudomonas aeruginosa may have minimal inhibitory concentration (MIC) values lower than ofloxacin concentrations achieved in bronchial secretions, although some isolates are less sensitive. Clinical studies should establish the relevance of pharmacokinetic data to respiratory infections caused by organisms of borderline susceptibility.
Cephalosporins in gram-positive infections.
Infections caused by Gram-positive bacteria are an important and common cause of morbidity and mortality. Staphylococci and streptococci are the most frequent infecting organisms in skin and soft tissue infections, pneumonia, bone and joint infections, and endocarditis. Anaerobic Gram-positive bacteria such as Clostridia spp. cause infections that can rapidly produce tissue necrosis and death. The cephalosporins are indicated for the treatment of infections caused by Gram-positive bacteria in certain circumstances. These include selected patients with endocarditis, osteomyelitis, septic arthritis and cellulitis. They are also used as alternatives to the penicillins in penicillin-allergic patients and for 'mixed' infections caused by Gram-positive and Gram-negative organisms. This article discusses the indications for the cephalosporin group of antibiotics in patients suffering from infections caused by Gram-positive bacteria.
Amoxycillin, augmentin and metronidazole in bacterial vaginosis associated with Gardnerella vaginalis.
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The effect of human calcitonin on the cytoplasmic spreading of rat osteoclasts.
We previously found that calcitonin (CT), which inhibits osteoclastic bone resorption, abolished the cytoplasmic motility of isolated osteoclasts. The transition from motility to immotility was accompanied by a characteristic change in cell shape which coincided with the loss of pseudopodial ruffling activity and gradual cytoplasmic retraction. In this report we used computer-assisted morphometry to quantify the reduction in cytoplasmic spreading induced by human CT (hCT). Osteoclasts, isolated from neonatal rat long bones, were allowed to spread on a plastic surface for 120 min. The outlines of six osteoclasts were recorded on a time-lapse video recorder. hCT, other hormones, or plasma samples were then added. The outlines of the same six osteoclasts were recorded after incubation, and the area covered by the cells after incubation was calculated as a percentage of the area covered by the same cells before hormone addition. Osteoclastic spreading was reduced by hCT in a dose-dependent manner and was significantly decreased by concentrations of 2 pg/ml and above. High concentrations of PTH and 1,25-dihydroxyvitamin D3 had no effect on osteoclasts. This technique is a sensitive and quantitative assay of hCT concentration which is unaffected by the presence of other calcium-regulating hormones likely to be present in plasma.
Penetration of ciclacillin into bronchial secretions.
The penetration of ciclacillin into bronchial secretions was investigated in 105 patients undergoing bronchoscopy after a single oral dose of 500 mg ciclacillin. Comparison was made with 26 patients who received 500 mg ampicillin by mouth. Over a 6 to 8 hour period, ciclacillin achieved significantly higher levels in bronchial secretions but no statistically significant difference between serum ampicillin and ciclacillin levels was detected.
Oral or parenteral antibiotic treatment in serious infections.
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Campylobacter enteritis in the community.
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Failure of the hydrogen breath test to detect pulmonary sugar malabsorption.
Five patients with sucrase-isomaltase deficiency, and one patient with primary glucose-galactose malabsorption had no increases in breath hydrogen excretion after oral sucrose or glucose. Anaerobic incubation with sugars of stool suspensions from 5 patients with primary sugar malabsorption produced by trace of hydrogen (17 microliter) in only one, while those from 13 or 14 controls produced a mean hydrogen volume of 640 microliter under similar conditions. Altered bacterial metabolism is a probable explanation. Breath hydrogen excretion did increase appreciably in 2 of these patients after oral lactulose showing that hydrogen excretion may vary according to the substrate. Therefore, observation of breath hydrogen excretion after lactulose is not recommended as a means of predicting false-negative breath tests with other sugars. The hydrogen breath test is not a reliable mean of diagnosing primary sugar malabsorption in children.
Secnidazole--a nitroimidazole with a prolonged serum half-life.
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The effect of talampicillin on faecal flora.
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Sex differences in choice behaviour: the object-person dimension.
When viewing two conflicting stimuli in a stereoscope, males reported seeing objects significantly more often than human figures. The opposite effect was observed in females.