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Biomedical subjects

D N Taylor

Publications and source records attributed to D N Taylor.

At least 91 records · Page 5Linked to original sources
PubMed1991

Isolation of group 2 aerotolerant Campylobacter species from Thai children with diarrhea.

Campylobacter species were isolated from 93 (15%) of 631 Thai children with diarrhea using the membrane filter technique on nonselective blood agar incubated at 37 degrees C. Campylobacter jejuni was isolated from 62 (10%), Campylobacter coli from 14 (2%), and atypical campylobacters from 17 (3%). The 17 atypical strains were first characterized biochemically and by dot blot DNA hybridization. Catalase-negative strains also were characterized by DNA hybridization and ribotype pattern. One strain was a catalase-negative "Campylobacter upsaliensis" and another was a nitrate-negative Campylobacter jejuni doylei. Fifteen isolates were aerotolerant strains most closely resembling Campylobacter cryaerophila or "C. upsaliensis" by dot hybridization. These aerotolerant strains, designated group 2 ("Campylobacter butzleri"), had ribotypes distinct from C. cryaerophila and have previously been shown to be related by DNA hybridization at the species level to the group 2 aerotolerant Campylobacter type strain (D2686). Group 2 aerotolerant Campylobacter were the atypical Campylobacter species most frequently isolated from Thai children with diarrhea.

Campylobacter↗
PubMed1991

The epidemiology of Helicobacter pylori infection.

The evidence that H. pylori causes gastritis in humans comes from both primary and secondary observations. The most important primary observations are the human volunteer studies, the animal models, and the treatment studies with antimicrobial agents. Supporting information comes from studies showing the specific association of H. pylori infection with type B gastritis and with gastric (but not intestinal) epithelial cells; the specific ultrastructural lesions, including adherence pedestals; the ubiquity and stability of the immune response; the response to bismuth treatment; and the association with epidemic gastritis and hypochlorhydria. It is important to note that all of Koch's postulates have been fulfilled, and despite nearly universal initial skepticism, no evidence exists against the hypothesis that H. pylori plays an etiologic role in type B gastritis. Therefore, it is reasonable to conclude that H. pylori is a pathogen in humans. The known features of H. pylori infection are listed in. Infection is chronic and common throughout the world, with a higher prevalence in developing countries than in developed countries. The prevalence of H. pylori infection increases with age in parallel with that of gastritis. Acquisition of H. pylori infection does not appear to have any seasonality, and infection is equally common among men and women. Without a significant animal or environmental reservoir for human strains of H. pylori, person-to-person contact appears to be the most likely mode of transmission. Exactly how the organism is transmitted from the stomach of one person to that of another remains unclear. Also unknown are the factors which determine who becomes ill after infection; why one person has gastritis alone while another person develops a duodenal ulcer; and how the traditional risk factors for ulcer disease, such as smoking, aspirin, and alcohol, interact with H. pylori infection. Finally, the long term neoplastic consequences of infection must be understood. Further elucidation of the natural history of H. pylori and the consequences of H. pylori infection is the most important goal for future study.

Achlorhydria↗
PubMed1991

Lack of correlation between frontalis electromyography and self-ratings of either frontalis tension or state anxiety.

Since training in deep muscular relaxation is common to most behavioral treatments for anxiety and tension-related disorders, muscle tension measures, such as electromyography (EMG), would provide valuable information as to the efficacy of these treatments. In the past, however, the majority of clinical reports on behavioral treatments employing muscular relaxation have based results primarily on self-rated outcome measures, despite evidence in the literature of a lack of correspondence between self-ratings and physiological measures of muscle tension. An experiment was performed on 20 normal subjects comparing self-ratings of anxiety and frontalis muscle tension with frontalis EMG before and after a 15-min. relaxation period accompanied by frontalis EMG biofeedback. Analysis showed that the self-ratings of anxiety and frontalis tension correlated significantly both before and after the relaxation period. However, no correlation was observed between self-rated anxiety or frontalis tension and frontalis EMG either before or after the relaxation period. The relaxation period had no significant effect on the dependent measures. It is suggested that, if people are unable to report accurately on their somatic states, then physiological outcome measures, such as EMG, would be preferable to self-rated measures in assessments of relaxation training procedures.

Adult↗
PubMed1991

Effects of cranial transcutaneous electrical nerve stimulation in normal subjects at rest and during psychological stress.

Some effects of sub-threshold sine-wave transcutaneous electrical nerve stimulation (TENS), passed between earlobe electrodes at a constant alternating current (AC) frequency of 100 Hertz (Hz), were investigated in 90 normal subjects after 30 minutes of treatment, and after 3 minutes of standardized mental stress (mental arithmetic) which immediately followed the 30 minute treatment. In a double-blind protocol, five groups received 1) active TENS during treatment and active TENS during stress; 2) active TENS during treatment and placebo TENS during stress; 3) placebo TENS during treatment and placebo TENS during stress; 4) placebo TENS during treatment and active TENS during stress; and 5) no treatment during both treatment and stress. Results showed significant reductions in systolic blood pressure, pulse rate and anxiety, but not in diastolic blood pressure or peripheral vascular tension, after 30 minutes of active TENS as compared to no treatment. No placebo TENS effect was observed. No significant differences were observed between active TENS; placebo TENS and no treatment in physiological or psychological response to the stress procedure. Results are discussed in terms of the applicability of this technique to the management of stress.

Adolescent↗
PubMed1990

Technical and operative factors in infrarenal aortic reconstruction and their effect on the glomerular filtration rate in the immediate postoperative period and 6 months later.

Renal failure is an important cause of postoperative morbidity and mortality in infrarenal aortic reconstruction. Several mechanisms for this postoperative renal dysfunction have been suggested. However, biochemical testing of renal function is insensitive since it shows only gross renal changes. This study examined prospectively the effects of the technical and operative factors on renal function using radionuclide tests. The authors measured the total Glomerular Filtration Rate (GFR) using 51Cr-EDTA clearance in 59 patients undergoing elective infrarenal aortic reconstruction. We also examined the individual kidneys using 99mTc-DTPA renography and 99mTc-DMSA renal scanning. Renal scanning gives the percentage of function of each kidney, while renography gives a graphic assessment of individual renal perfusion and clearance. All tests were carried out preoperatively, 2 weeks postoperatively and 6 months later. Twelve technical factors including aortic cross clamping time, type of aortic anastomosis, forced diuresis, division of left renal vein and various others were recorded to study their effect on the GFR and the individual kidney function. The effect on renal function of these operative factors has not previously been described. GFR showed no change in the immediate postoperative period. Six months later GFR decreased, the mean decrease was 9 ml/min. (P = 0.007 Wilcoxon rank). Some of our patients showed an increased GFR, a phenomenon that was recognised recently. None of the factors studied, except division of the left renal vein, had any effect on the changes in the GFR in the immediate postoperative period or 6 months later.

Acute Kidney Injury↗
PubMed1990

Trimethoprim resistance gene in Shigella dysenteriae 1 isolates obtained from widely scattered locations of Asia.

Trimethoprim-resistance genes of Shigella dysenteriae 1 strains, isolated from a different location of six different countries of Asia over a 5-year period were characterized by using three different dihydrofolate reductase (DHFR) gene probes. The trimethoprim-resistant (TMPR) strains hybridized only with the type I DHFR gene probe by colony hybridization. None of the strains hybridized with types II and III DHFR gene probes. Southern blot experiments using plasmid DNA extracted from these resistant strains indicated that the type I DHFR genes were either on a 20 MDa plasmid or might be located on the chromosome. None of the other plasmids present in S. dysenteriae 1 strains hybridized with the probe. This indicates that the TMP resistance in these S. dysenteriae 1 strains are mediated by type I DHFR enzyme, and there may be transposition of this type I DHFR gene occurs between the 20 MDa plasmid and the chromosome in this serotype of shigella.

Asia↗
PubMed1990

Seroprevalence of Helicobacter pylori infections in Thailand.

Serologic studies in developed countries indicate that Helicobacter (formerly Campylobacter) pylori infection is uncommon until the third decade of life and achieves a peak prevalence of 50% in the seventh decade. In developing countries the epidemiology of H. pylori has not well been described. A sensitive and specific serologic assay for H. pylori infection was validated in Thai patients also studied by culture and histologic examination of biopsy specimens. The prevalence of H. pylori antibodies in persons from a rural Thai community began early (17.5% of children 5-9 years old), increased to 55% during the third decade of life, and peaked (75%) in the 30- to 49-year age group. At a Bangkok orphanage where enteric infections are hyperendemic, 74% of children 1-4 years old were seropositive. This study shows that the prevalence of H. pylori infection in Thailand is higher than in industrialized countries. The high infection rate at the orphanage suggests that person-to-person transmission of H. pylori may be occurring.

Antibodies, Bacterial↗
PubMed1990

Serotyping of human group A rotavirus with oligonucleotide probes.

Rotaviruses (RV) in stools of children with diarrhea in Thailand were serotyped by monoclonal enzyme immunoassay (MEIA), and RNA extracted from these specimens were tested for hybridization with oligonucleotides constructed from the nucleotide sequences of VP7 of human serotypes 1, 2, 3, and 4. Of 178 specimens that contained RV as identified with a monoclonal antibody to group A RV, 84% (149/178) hybridized with serotype-specific oligonucleotides, and 42% (74/178) were serotyped by MEIA (P less than .001). Of the 74 specimens that were serotyped by MEIA, 92% (35/38) of type 1, 97% (34/35) of type 2, and the one type 4 RV hybridized with the HuG1Ac, HuG2Ac, and HuG4Ac oligonucleotides, respectively. RV strains identified in children in Thailand in 1987 and 1988 to which a serotype could be assigned by either method were either type 1, type 2, or, less often, type 4. Testing RV for hybridization with oligonucleotides for genes encoding VP7 is an alternate method of determining RV serotypes.

Antibodies, Monoclonal↗
PubMed1990

Endemic Cryptosporidium and Giardia lamblia infections in a Thai orphanage.

We conducted a point prevalence survey for enteric protozoa in 205 institutionalized orphans 1-61 months of age in Bangkok, Thailand. Cryptosporidium was identified in 17 children (8%), Giardia lamblia in 42 (20%), and 3 children (1%) had both parasites. At the time of diagnosis, diarrheal symptoms were present in a minority of subjects: 36% of children with Cryptosporidium alone, 10% with G. lamblia alone, and in 20% of those with neither parasite. Although chronic nutritional status (height/age) was similar in all groups, acute nutritional status (weight/height) was lower only in children with Cryptosporidium (Z score = -1.39 +/- 0.13) compared with children with G. lamblia (mean Z score +/- SEM = -0.56 +/- 0.26) or neither parasite (Z score = -0.78 +/- 0.13; P = 0.05). Detectable levels of Cryptosporidium-specific IgG antibodies by ELISA were identified in 15 of 16 Thai children with Cryptosporidium and in 17 of 19 Thai children without Cryptosporidium (mean OD +/- SEM = 1.27 +/- 0.18 vs. 1.06 +/- 0.13, respectively), but in only 1 of 18 sera from toddlers in day-care centers in Denver, CO (OD = 0.128 +/- 0.03). Although neither infection with Cryptosporidium nor G. lamblia was consistently associated with acute diarrheal symptoms, Cryptosporidium was more often associated with depressed acute nutritional status than G. lamblia. The high prevalence of specific antibodies to Cryptosporidium in Thai orphans suggests an association between high rates of exposure with asymptomatic excretion of the parasites.

Animals↗
PubMed1990

Serum antibodies to Giardia lamblia by age in populations in Colorado and Thailand.

We measured levels of antibodies to Giardia lamblia by age in serum specimens from persons in Denver, Colorado, and Soongnern, Thailand. Serum levels of immunoglobulin (Ig) G, IgM, and IgA G lamblia-specific antibodies measured by enzyme-linked immunosorbent assay increased substantially during childhood in both geographic areas, although children in Soongnern showed significantly higher mean levels of each antibody class (P less than .05). After adolescence, levels of G lamblia-specific IgM fell steadily with age in both populations. In contrast, specific IgA levels remained elevated throughout life among the Thai but decreased to low levels among adults in Denver. Similarly, rates of carriage of G lamblia were high among children aged 1 to 4 years in Denver and Soongnern (14.3% versus 26.5%, respectively) but were much lower among adults in Denver (0% versus 14%; P less than .01). These data suggest that levels of G lamblia-specific IgM may reflect exposure to the parasite early in life in both areas. Levels of parasite-specific IgA may reflect recurrent exposure to G lamblia in Soongnern, where G lamblia is endemic, but less frequent exposure to the parasite in Denver, where exposure is often episodic.

Adolescent↗
PubMed1989

Pulmonary artery versus left ventricular venting: a radioisotope study of left ventricular function.

Radionuclide measurements of ejection fraction were used to assess immediate and late postoperative ventricular function after the use of either a pulmonary artery vent (group A) or a left ventricular vent (group B) in 20 patients undergoing aortic valve replacement for pure aortic stenosis. Ten patients were included in each group and anesthetic techniques, patient management, and septal temperatures were similar in all cases. No significant difference was found between the preoperative and immediate or 6-week postoperative ejection fractions, either taken overall or between the two groups (p greater than 0.05; Student's t test). No correlation was found between cross-clamp time, bypass time, or the occurrence of ventricular fibrillation and the immediate postoperative ejection fraction (p greater than 0.05; Student's t test). There was no significant difference in the incidence of ventricular fibrillation after each type of vent had been used (chi 1(0) = 3.32; p greater than 0.05). We did not demonstrate any abnormalities in regional wall motion associated with apical insertion of a left ventricular vent, and conclude that pulmonary artery and left ventricular vents are equally satisfactory in terms of postoperative ventricular performance.

Adult↗
PubMed1989

Case-control study of endemic diarrheal disease in Thai children.

In a year-long, case-control study of endemic diarrheal disease among 1230 Thai children less than five years of age, rotavirus was detected in 20%, Campylobacter in 13%, Shigella in 13%, Salmonella in 12%, and enterotoxigenic Escherichia coli (ETEC) in 9%. The differences in detection of enteric pathogens between patients and controls was significant for rotavirus (P less than .001), Shigella (P less than .001), ETEC that produced heat-labile and heat-stable toxins (LT and ST; P = .005), and ST only (P less than .001). C. jejuni was most significantly associated with diarrhea in children less than 12 months [corrected] old (P = .037) and Salmonella in children less than three months of age (P = .003). Enteropathogenic E. coli (EPEC) that adhered in a localized pattern to HeLa cells was isolated from 7% of patients and 3% of controls less than six months of age. Only 50% of these E. coli strains were of EPEC serotypes. Enteroinvasive E. coli was isolated from 7% of patients more than two years of age, and new serotypes were identified.

Age Factors↗
PubMed1989

Group C rotavirus infections in patients with diarrhea in Thailand, Nepal, and England.

Atypical rotavirus obtained from fecal specimens of six patients with diarrhea from Thailand, Nepal, and England were characterized by using polyacrylamide gel electrophoresis and immune electron microscopy. The electropherotypes were characteristic of the porcine reference group C rotavirus strain but demonstrated considerable strain-to-strain variation. Human convalescent group C sera had a high titer (1:320) when tested against the human isolates and a low titer (1:40) when tested against a porcine reference strain (Cowden). When porcine antiserum (Cowden) was tested against the human isolates, the titers ranged from 1:40 to 1:320, indicating significant antigenic diversity between strains. Group C rotavirus appears to have a worldwide distribution as an agent associated with diarrhea in children and adults.

Adult↗
PubMed1989

Diagnosis of coronary artery disease using thallium imaging: tomographic versus planar imaging.

Coronary artery disease was evaluated with tomographic and planar thallium imaging in 31 subjects who had undergone coronary angiography for assessment of chest pain syndrome. Coronary arteriography revealed significant coronary artery disease in 17; and 14 had normal coronary arteries. The sensitivity and specificity for planar imaging was 71% and 79%, and that for tomography, 94% and 79% respectively. The sensitivity and specificity figures for individual coronary artery lesion detection for planar imaging were 87/83 for LAD, 33/100 for LCX and 50/86 for RCA respectively, and for tomography the figures were 87/87 for LAD, 33/95 for LCX and 90/76 for RCA respectively. The use of coronary arteriography as a gold standard was considered by assessing its interobserver variability, which was 16%. The interobserver variability for thallium imaging was 8% and 3% respectively for tomographic and planar acquisitions.

Adult↗
PubMed1989

A simple method of identifying loosening or infection of hip prostheses in nuclear medicine.

Joint replacement is now established as a reliable orthopaedic procedure for the relief of many painful degenerative conditions of the hip. When successful it enhances hip movement and relieves pain with a concomitant improvement in function and well being for the patient. When unsuccessful the persistence of pain usually signifies loosening or infection. Loosening may result from mechanical failure or infection. Accurate distinction between septic and aseptic loosening is important for planning and executing surgical intervention. The experience of the Department of Nuclear Medicine in Coventry assessing pathology in painful hip prostheses was retrospectively reviewed in 47 patients. These patients were imaged from 1985 to 1987 and all had good clinical follow-up enabling the diagnosis of loosening, infection or normal to be made with confidence. All patients had three phase bone imaging and some had additional gallium imaging. The images were reviewed with particular emphasis on the pattern of uptake in the late bone image and congruence of abnormal uptake in the early bone image and gallium image. It is concluded that for the majority of patients simple three phase bone imaging will provide the required diagnostic information.

Aged↗