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Biomedical subjects

D N Taylor

Publications and source records attributed to D N Taylor.

At least 145 records · Page 8Linked to original sources
PubMed1986

Plasmids coding for colonization factor antigens I and II, heat-labile enterotoxin, and heat-stable enterotoxin A2 in Escherichia coli.

Colonization factor antigens I and II (CFA/I and CFA/II) are important in the pathogenesis of diarrhea in humans caused by some enterotoxigenic Escherichia coli (ETEC). Plasmid DNA from 16 CFA/I+ and five CFA/II+ ETEC were examined by Southern blot analysis with enterotoxin gene probes and were compared with plasmid DNA from derivatives of the same ETEC that had lost the ability to produce these colonization factors. Among the 16 CFA/I+ ETEC strains, the loss of CFA/I was accompanied by the loss of a plasmid of between 34 and 68 megadaltons (MDa) coding for heat-stable enterotoxin A2 (ST-A2) in 12 strains, by the loss of a 60-MDa plasmid coding for heat-labile enterotoxin (LT) and ST-A2 in one strain, or by deletions of a segment of DNA encoding for ST-A2 in three strains. Among five CFA/II+ ETEC strains, the loss of CFA/II was associated with the loss of a plasmid of 75 MDa coding for LT and ST-A2 in three strains, with the loss of genes coding for LT and ST-A2 from a 68-MDa plasmid in one strain, or with no discernible loss of a plasmid or DNA sequences coding for enterotoxins in the remaining strain. The loss of CFA/I and CFA/II production was associated with the loss of DNA sequences encoding for ST-A2 in 20 of 21 ETEC examined.

Antigens, Bacterial↗
PubMed1986

Nuclear cardiology: a comparison of equilibrium gated blood pool and gamma camera first-pass measurements for the assessment of left-ventricular regional wall motion.

There are two major problems remaining for the successful assessment of left-ventricular regional wall motion (RWM) using nuclear cardiology. These are as follows. Which technique should be used: first pass or equilibrium? Secondly, which views should be used to give full information about the RWM of the left ventricle? This paper specifically considers each of these questions and concludes that equilibrium blood pool imaging in both the right anterior oblique and left anterior oblique projections is currently the best option.

Heart↗
PubMed1986

Deaths following ingestion of a cardiotoxic plant in Kampuchean children in Thailand.

Twenty-seven Khmer children at a refugee camp in Thailand developed vomiting and diarrhea after ingestion of the seeds of the plant Erythrophleum succirubrum Gagnep. Two children died of cardiac arrest. Ingestion of seed of Erythrophleum species that contain digitalis-like alkaloids causes fatal epidemics of poisoning in children as well as livestock.

Arrhythmias, Cardiac↗
PubMed1985

A non-radioactive DNA probe to identify Shigella and enteroinvasive Escherichia coli in stools of children with diarrhoea.

A non-radioactive biotinylated DNA probe was constructed to detect Shigella and enteroinvasive Escherichia coli (EIEC). Specimens were examined with the biotinylated probe after removing streptavidin-binding glycoproteins with proteinase K. Both biotinylated and radioactive probes detected 125 pg of target-cell DNA after hybridisation for 24 h and exposure to indicator dyes or X-ray film for 4 h. Both probes hybridised with 52 EIEC and none of 16 non-EIEC examined; they also hybridised with stool blots from 11 of 13 children with culture-proven shigellosis or EIEC diarrhoea and were negative with stool blots from 43 children who were culture negative for Shigella and EIEC. Biotinylated DNA probes can be as sensitive as radiolabelled probes, but have the advantage of a longer shelf-life and greater availability.

Biotin↗
PubMed1985

Rapid identification of penicillinase-producing Neisseria gonorrhoeae by detection of beta-lactamase in urethral exudates.

The production of fluorescent end-products with ampicillin as substrate can be used to detect beta-lactamase activity in biological fluids. A fluorescent spot test was evaluated as a rapid method of detecting beta-lactamase in the urethral exudates of men infected with Neisseria gonorrhoeae in Thailand. Among 208 men with culture-proven gonococcal urethritis, the fluorescent spot test was positive in 92 of 101 men from whom penicillinase-producing N gonorrhoeae (PPNG) were isolated and in 4 of 107 men from whom non-PPNG were isolated. The fluorescent spot test is a rapid, inexpensive, and sensitive method to detect PPNG and may be valuable in determining appropriate treatment for patients with gonococcal urethritis.

Exudates and Transudates↗
PubMed1985

Polymicrobial aetiology of travellers' diarrhoea.

Of 35 US Peace Corps volunteers in Thailand, 20 (57%) had a total of 30 episodes of diarrhoea during their first 6 weeks in the country. Enteric pathogens were associated with 90% of the episodes. A single pathogen was identified in 17 (57%) episodes, 2-4 pathogens were identified in 10 (33%) episodes, and there were 15 symptomless infections. Enterotoxigenic Escherichia coli (ETEC) was identified in 37% of these episodes, and various salmonella serotypes were isolated in 33%. Infections with 9 other enteric pathogens were also identified: Campylobacter jejuni (17%), Plesiomonas shigelloides (13%), Aeromonas hydrophila (10%), Blastocystis hominis (7%), Norwalk virus (7%), Vibrio parahaemolyticus (3%), non-O1 Vibrio cholerae (3%), Vibrio fluvialis (3%), and rotavirus (3%). In total, 56 enteric infections were documented in 35 volunteers.

Adult↗
PubMed1985

Identification by DNA hybridization of enterotoxigenic Escherichia coli in a longitudinal study of villages in Thailand.

Radioactively labeled enterotoxin genes were used to study the epidemiology of enterotoxigenic Escherichia coli infections in two Thai villages. When E. coli that were isolated from 674 specimens were fixed on nitrocellulose paper and examined for hybridization with E. coli enterotoxin gene probes in Bangkok, the technique had a sensitivity of 94% (31 of 33) and a specificity of 100% (641 of 641), when compared with tests of E. coli for enterotoxin production in the Y-1-adrenal cell and suckling-mouse assays. However, when the same specimens were fixed directly onto nitrocellulose paper at a field laboratory and transported to the reference laboratory for assay with the gene probes, 27 specimens that contained enterotoxigenic E. coli did not hybridize with the E. coli gene probes. Enterotoxigenic E. coli that hybridized with the LT, ST-H, and ST-P probes were identified in 10% (17 of 177) of villagers with diarrhea, 7% (8 of 108) of contacts of individuals with diarrhea caused by enterotoxigenic E. coli, and 3% (32 of 1,199) of persons not associated with cases of diarrhea caused by enterotoxigenic E. coli. Enterotoxigenic E. coli that hybridized with the ST-II probe was not a cause of diarrhea. Alternative methods of retaining DNA on filters under field conditions are needed before this technique can be used for direct examination of specimens with enterotoxin gene probes.

Adolescent↗
PubMed1985

Comparative study of ceftriaxone and trimethoprim-sulfamethoxazole for the treatment of chancroid in Thailand.

A single dose of ceftriaxone (250 mg) administered intramuscularly was compared with trimethoprim-sulfamethoxazole (TMP-SMZ; 160/800 mg) administered orally twice daily for seven days or with a single dose of TMP-SMZ (640/3,200 mg) administered orally for the treatment of chancroid in men in Thailand. Haemophilus ducreyi was isolated from 79 (48%) of 164 men with a clinical diagnosis of chancroid. For men with ulcers that were culture positive for H. ducreyi, rates of cure were 100% in 25 men treated with ceftriaxone, 87% in 23 men given TMP-SMZ for seven days, and 55% in 31 men given TMP-SMZ in a single dose. For men with ulcers that were culture negative for H. ducreyi, rates of cure were 100% in 29 men treated with ceftriaxone, 66% in 32 men given TMP-SMZ for seven days, and 63% in 24 men given TMP-SMZ in a single dose. The MIC50 of the three antibiotics for 94 isolates of H. ducreyi were as follows: 0.004 micrograms/ml for ceftriaxone, 16 micrograms/ml for trimethoprim, and greater than 512 micrograms/ml for sulfamethoxazole. Our study indicates that ceftriaxone in a single dose of 250 mg is effective, but that TMP-SMZ, even when given in a standard seven-day regimen, is not effective treatment for chancroid in Thailand.

Administration, Oral↗
PubMed1985

Escherichia coli contains plasmids coding for heat-stable b, other enterotoxins, and antibiotic resistance.

Plasmid DNAs obtained from 18 Escherichia coli isolates that hybridized with the heat-stable b (ST-b) enterotoxin gene probe were examined by Southern blot analysis for genes coding for heat-labile, ST-a, and ST-b enterotoxins with specific radiolabeled DNA probes. Four E. coli isolates contained plasmids coding for both heat-labile and ST-b enterotoxins, and one isolate contained a plasmid coding for ST-a and ST-b. Five of 11 isolates of antibiotic-resistant enterotoxigenic E. coli isolates containing ST-b-coding DNA transferred a plasmid coding for both antibiotic resistance and ST-b to E. coli K-12, suggesting that the widespread use of antibiotics could increase the distribution of genes coding for ST-b.

Anti-Bacterial Agents↗
PubMed1985

Antimicrobial susceptibility and characterization of outer membrane proteins of Haemophilus ducreyi isolated in Thailand.

One hundred strains of Haemophilus ducreyi isolated in Thailand from patients with chancroid were tested by the agar dilution method against 10 antimicrobial agents and typed by outer membrane protein pattern by using sodium dodecyl sulfate gel electrophoresis. All strains produced beta-lactamase and were resistant to tetracycline, kanamycin, and sulfonamides. Most had a decreased susceptibility to trimethoprim (MIC for 50% of the strains [MIC50], 0.5 micrograms/ml) and chloramphenicol (MIC50, 8 micrograms/ml). Strains were susceptible to ciprofloxacin (MIC90, 0.001 micrograms/ml), ceftriaxone (MIC50, 0.0015 micrograms/ml), erythromycin (MIC50, 0.015 micrograms/ml), rosoxacin (MIC50, 0.03 micrograms/ml), and spectinomycin (MIC50, 8 micrograms/ml). The degree of antimicrobial resistance found in Thailand is higher than that reported for H. ducreyi isolated in other regions. Five different outer membrane protein patterns were found by analyzing proteins in the range of 29 to 61 kilodaltons, but 98% of the Thai strains fell into three patterns which did not differ greatly. Outer membrane protein patterns of Thai strains were also seen in strains from other geographic areas. A new outer membrane protein type was found among nine strains isolated in Singapore.

Bacterial Outer Membrane Proteins↗
PubMed1985

Thallium-201 scintigraphy for ischaemic heart disease and infarct detection: comparison of rotating slant-hole tomography and planar imaging.

A trial was undertaken to compare the diagnostic capabilities of rotating slant-hole tomography and raw scintigraphic planar images for the assessment of ischaemic heart disease and for infarct detection. Twenty patients with coronary artery disease established by arteriography and 29 patients who had suffered acute myocardial infarction as established by ECG and enzyme criteria were imaged, along with ten normal volunteers. Overall sensitivity and specificity figures, as well as Receiver Operating Characteristics (ROC) curves, were obtained. For infarct detection there was a sensitivity of 93% for tomography and 96% for planar imaging while the specificity was 80% for tomography and 95% for planar imaging. This loss of sensitivity and specificity was also apparent in the ROC curves and showed that there was no advantage from the use of rotating slant-hole tomography. For ischaemic heart disease the sensitivities for tomography and planar imaging were 83% and 91% respectively, while the specificities were 83% and 90% respectively. The ROC analysis again showed this reduction in the diagnostic capability of the test. It was concluded that rotating slant-hole tomography was no advantage in the assessment of ischaemic heart disease. Inter-and intra-observer variability was good with consistent responses in more than 90% of cases. No significant improvement was demonstrated in the poor ability of thallium scanning to specify the diseased vessels, and the phenomenon of false defects in the rotating slant-hole tomographic scans of some normal subjects was shown to affect the response of observers significantly.

Aged↗
PubMed1985

A comparative study of enterotoxigenic Escherichia coli, Shigella, Aeromonas, and Vibrio as etiologies of diarrhea in northeastern Thailand.

The incidence of enterotoxigenic Escherichia coli (ETEC), Shigella, Aeromonas, and Vibrio was determined in patients with diarrhea seen at a hospital in northeastern Thailand, and compared with the incidence of these bacteria in household contacts and their neighbors. ETEC was identified in 17%, Shigella in 9%, Aeromonas in 9%, V. parahaemolyticus in 5%, and non-01 V. cholerae in 2% of 299 patients with diarrhea. These five species of bacteria were isolated more often from patients with diarrhea than persons without diarrhea (P less than 0.001). ETEC was found more often in household contacts (22/141) and neighbors (18/147) of index cases than in persons living in homes not associated with ETEC infections (32/1,318; P less than 0.001). While Shigella was isolated less often in family contacts (3/76) and neighbors (4/93) of patients with shigellosis, this enteric pathogen was also isolated more often from contacts than persons not associated with Shigella infection (13/1,437; P less than 0.001). Both Aeromonas and non-01 V. cholerae can also be enteric pathogens; further efforts should be made to define the enteropathogenicity of these bacteria.

Adolescent↗
PubMed1985

DNA hybridization in the diagnosis of bacterial diarrhea.

DNA hybridization with either cloned genes for enteropathogenic determinants or DNA segments that are species-specific is a valuable tool to identify certain bacterial enteric pathogens. Thus far, only E. coli and V. cholerae enterotoxin gene probes have been used to identify ETEC and V. cholerae in clinical specimens. DNA probes developed for Salmonella, Shigella, Campylobacter, and enteroinvasive and enteropathogenic E. coli need to be evaluated with clinical specimens. The major contribution of this system so far has been to examine large numbers of specimens in epidemiologic studies. Once nonradioactive DNA probes are developed, this system will have potential application in clinical laboratories and in research laboratories in the developing world where diarrheal disease causes its greatest impact.

Bacterial Infections↗