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Biomedical subjects

D N Taylor

Publications and source records attributed to D N Taylor.

At least 73 records · Page 4Linked to original sources
PubMed1993

Diarrhoeal disease: current concepts and future challenges. Molecular biological approaches to the epidemiology of diarrhoeal diseases in developing countries.

Diarrhoea in developing countries is caused by an increasingly long list of bacterial, viral, and parasitic pathogens with rotavirus, enterotoxigenic Escherichia coli, Campylobacter, Shigella, and Salmonella heading the list. Using methods to detect most of the known enteropathogens, one or more enteropathogen(s) is isolated in two-thirds of diarrhoeal illnesses in the developing world. Many of these enteropathogens are also frequently isolated from children without diarrhoea. An aetiologic agent is more frequently isolated from cases of invasive diarrhoea than from those with secretory diarrhoea. Deoxyribonucleic acid probes have proved very useful in detecting pathogens such as enterotoxigenic (ETEC), enteroinvasive (EIEC), and enteropathogenic E. coli (EPEC), but have not yet proved to be particularly rapid or less expensive. Molecular biology has proved useful in epidemiological studies as a means of strain identification. Plasmids were initially used as convenient markers and proved useful in identifying epidemic strains of bacteria. Other molecular markers, such as ribotyping, are accurate enough to be used as taxonomic tools.

Bacterial Infections↗
PubMed1993

Safety and immunogenicity of the oral, whole cell/recombinant B subunit cholera vaccine in North American volunteers.

A newly formulated, oral, inactivated whole cell plus recombinant B subunit (WC/rBS) cholera vaccine was evaluated in US military personnel. In the first study, 74 subjects were given two doses 14 days apart. In the second study, 186 subjects were randomized into four groups; two groups received vaccine with either full (4 g) or half (2 g) strength bicarbonate buffer, and two groups received either full or half strength buffer without vaccine. Mild gastrointestinal symptoms were associated with full buffer (P = .02) but not with the vaccine. In the first study, 36% of all subjects and 55% with low prevaccination titers (< 1:40) had a > or = 2-fold rise in vibriocidal antibody level; > 80% of subjects developed a 4-fold rise in anti-cholera toxin (CT) titers. Post-vaccination IgA and IgG anti-CT titers were approximately 1.5-fold higher among persons receiving full strength buffer (P = .05). The WC/rBS vaccine is safe and immunogenic in North Americans, although some mild gastrointestinal symptoms occur with the high concentration of buffer necessary to protect the B subunit from gastric acid denaturation. Prior immunity to cholera conferred by parenteral vaccine decreased vibriocidal antibody response.

Administration, Oral↗
PubMed1993

Campylobacter immunity and quantitative excretion rates in Thai children.

Campylobacter species were isolated from 61 (15%) of 416 Thai children < 5 years old with diarrhea. Although the baseline levels of Campylobacter-specific antibody increased with age, 80.3% of Campylobacter-infected children seroconverted compared with 12.9% of 45 Shigella-infected patients used as controls. The response to acute infection was greatest in the 6- to 12-month-old group. Nonseroconverters had higher initial IgG levels than did seroconverters (P = .001). Quantitative cultures showed a range of 1-8 log10 Campylobacter cfu/g of stool (median, 6.0 log10), and the seroconversion rate was highest in those with the highest Campylobacter excretion. Fecal Campylobacter excretion was inversely related to age (chi 2 for trend, P = .03). These studies indicate that endemic Campylobacter exposure frequently induces seroconversion in young children, whether Campylobacter is isolated as a single pathogen or one of multiple pathogens, and that fecal excretion of the organism is inversely related to the age-related immune response to infection.

Acute Disease↗
PubMed1993

Sine-wave auricular TENS produces frequency-dependent hypesthesia in the trigeminal nerve.

OBJECTIVE: To evaluate the effects of different frequencies of auricular (ear-to-ear) sine-wave transcutaneous electrical nerve stimulation (TENS), administered at subliminal intensity, on trigeminal nerve sensitivity. DESIGN: In a double-blind protocol, healthy volunteer subjects were administered one of three different frequencies of active TENS (5, 100, or 2,000 Hz) or placebo TENS (no current was passed) for 30 min. SETTING: Department of Psychology, City University of New York. SUBJECTS: 72 healthy undergraduate volunteers with no preexisting pain problems (16 men and 56 women), from the Department of Psychology, City University of New York. OUTCOME MEASURE: Pretreatment to posttreatment changes were measured in sensation threshold for a 250-Hz electrical stimulus applied transcutaneously to an area 1 cm anterior to the tragus of the ear (mandibular division of the trigeminal nerve). RESULTS: Analysis of variance indicated no group differences in baseline trigeminal sensation threshold, but there were significant group differences in pretreatment to posttreatment changes in sensation threshold (p < 0.001). A postiori analysis showed significant increases in trigeminal sensation threshold after active TENS as compared to placebo TENS (p < 0.05), with 5- and 100-Hz TENS producing significantly greater hypesthesia than 2,000-Hz TENS (p < 0.05). CONCLUSIONS: Sine-wave auricular TENS produces frequency-dependent trigeminal hypesthesia that is not a placebo effect.

Adolescent↗
PubMed1993

Synthesis, characterization, and clinical evaluation of conjugate vaccines composed of the O-specific polysaccharides of Shigella dysenteriae type 1, Shigella flexneri type 2a, and Shigella sonnei (Plesiomonas shigelloides) bound to bacterial toxoids.

The theoretic basis for developing conjugate vaccines, to induce immunoglobulin G (IgG) lipopolysaccharide (LPS) antibodies for the prevention of shigellosis, has been described (J. B. Robbins, C.-Y. Chu, and R. Schneerson, Clin. Infect. Dis. 15:346-361, 1992). The O-specific polysaccharides (O-SPs) of Shigella dysenteriae type 1, S. flexneri type 2a, and S. sonnei were covalently bound to carrier proteins. Alone, the O-SPs were not immunogenic in mice. Conjugates of these O-SPs, injected into young outbred mice subcutaneously as saline solutions containing 2.5 micrograms of saccharide, elicited serum IgG and IgM antibodies with booster responses; adsorption onto alum enhanced their immunogenicity. Injection of 25 micrograms of these conjugates into adult volunteers elicited mild local reactions only. Each conjugate induced a significant rise of the geometric mean serum IgG, IgM, and IgA LPS antibody levels. A second injection 6 weeks later did not elicit booster responses, and adsorption of the conjugates onto alum did not enhance their immunogenicity. Conjugate-induced levels of IgA, but not IgG or IgM, declined to preimmunization levels at day 56. The levels of postimmunization antibodies of the three immunoglobulin classes were similar to or higher than those of recruits in the Israel Defense Force following shigellosis caused by S. flexneri type 2a or S. sonnei. These data provide the basis for evaluating these conjugates to prevent shigellosis.

Adolescent↗
PubMed1993

Characterization of enterotoxigenic Escherichia coli isolated from U.S. troops deployed to the Middle East.

Enterotoxigenic Escherichia coli (ETEC) was a common cause of traveler's diarrhea in U.S. soldiers in the Middle East in 1989 and 1990. To determine which bacterial components would be useful in a vaccine, potential protective antigens (toxin, colonization factor antigen [CFA], and serotype) from 189 ETEC isolates were examined. Nearly half of the isolates expressed both ETEC toxins, 39% had only heat-stable enterotoxin (ST), and 17% had heat-labile enterotoxin (LT). CFA/I was the least common colonization factor antigen (11%), CFA/II was common (34%), as was CFA/IV (31%), and 24% expressed none of these CFAs. Fifty-seven O:H serotypes were found. Serotype O6:H16 was the most common, occurring in 29% of the ETEC isolates, usually with LT-ST and CFA/II. Generally, CFA/II was associated with expression of both toxins, CFA/IV was associated with expression of ST, and none of the CFAs was routinely found with LT. We conclude that ETEC from soldiers in the Middle East expressed a variety of antigens and that an effective vaccine will require multiple protective antigens.

Antigens, Bacterial↗
PubMed1993

Serologic response to Helicobacter pylori among children and teenagers in northern Chile.

The serologic response to Helicobacter pylori was determined in 388 children and teenagers living in Iquique, Chile by using an IgG enzyme-linked immunosorbent assay. Serum antibody levels, as measured by optical density, correlated strongly with age. Increases in the mean antibody level were seen primarily after age five, with rates of seropositivity increasing to > or = 70% among teenagers. The reasons for this age-related pattern of acquisition of infection remain to be determined.

Adolescent↗
PubMed1992

The effect of infrarenal aortic reconstruction on glomerular filtration rate and effective renal plasma flow.

Compromised patients with aortic disease are vulnerable to various complications from aortic reconstruction. These complications are related to changes in systemic haemodynamics during aortic cross-clamping, which leads to cardiac stress and alteration in regional blood flow to different organs. One of the most important postoperative complications is renal failure which is associated with a high mortality rate. Circulatory alterations within the kidney must play a role in the pathogenesis of renal dysfunction that may follow infrarenal aortic cross-clamping and reconstruction. To study the effects of abdominal aortic reconstruction on renal function and perfusion, we measured prospectively the glomerular filtration rate (GFR, n = 59), effective renal plasma flow (ERPF, n = 38) and left ventricular ejection fraction (LVEF, n = 38) in patients undergoing elective infrarenal aortic reconstruction. Radionuclide techniques were used. The three parameters were measured at three time points: preoperatively, postoperatively and 6 months after surgery. The LVEF was measured in order to reflect the patient's cardiac status and pre-renal perfusion. We also measured the three parameters in two control groups of patients: a group of patients undergoing major colonic surgery and a group of patients with arterial disease under conservative management. Six months after surgery the GFR had decreased in 67% of aortic reconstruction patients. Overall GFR in the aortic reconstruction group decreased by a mean of 9 ml min-1 (p = 0.007). This was associated with a decrease in the ERPF in 48.5% of patients. The mean decrease in ERPF in the aortic reconstruction group was 74 ml min-1 (p = 0.05). The LVEF was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Treatment of traveler's diarrhea with ciprofloxacin and loperamide.

To determine the efficacy of loperamide given with long- and short-course quinolone therapy for treating traveler's diarrhea, 142 US military personnel were randomized to receive a single 750-mg dose of ciprofloxacin with placebo, 750 mg of ciprofloxacin with loperamide, or a 3-day course of 500 mg of ciprofloxacin twice daily with loperamide. Culture of pretreatment stool specimens revealed campylobacters (41%), salmonellae (18%), enterotoxigenic Escherichia coli (ETEC, 6%), and shigellae (4%). Of the participants, 87% completely recovered within 72 h of entry. Total duration of illness did not differ significantly among the three treatment groups, but patients in the 3-day ciprofloxacin plus loperamide group reported a lower cumulative number of liquid bowel movements at 48 and 72 h after enrollment compared with patients in the single-dose ciprofloxacin plus placebo group (1.8 vs. 3.6, P = .01; 2.0 vs. 3.9, P = .01). While not delivering a remarkable therapeutic advantage, loperamide appears to be safe for treatment of non-ETEC causes of traveler's diarrhea. Two of 54 patients with Campylobacter enteritis had a clinical relapse after treatment that was associated with development of ciprofloxacin resistance.

Campylobacter Infections↗
PubMed1992

Safety and immunogenicity of different immunization regimens of CVD 103-HgR live oral cholera vaccine in soldiers and civilians in Thailand.

Attenuated Vibrio cholerae oral vaccine CVD 103-HgR was well tolerated by 324 Thai soldiers and civilians. Most received a single 5 x 10(8) cfu dose, while 40 each received one or two 5 x 10(9) cfu doses. Vibriocidal antibody (the best correlate of immunity) seroconversion was lower in soldiers than civilians (P less than .001). Increasing the vaccine dose to 5 x 10(9) cfu raised the geometric mean titer (P less than .001). A second 5 x 10(9) cfu dose one week later did not notably increase seroconversions. Likelihood of seroconversion was inversely correlated with baseline vibriocidal titer (P less than .001). CVD 103-HgR caused seroconversion in most subjects with baseline titers less than or equal to 1:40, including 100% of civilians after one 5 x 10(8) cfu dose, 79% of soldiers after one 5 x 10(9) cfu dose, and 45% of soldiers after one 5 x 10(8) cfu dose. In persons with elevated baseline titers, vibriocidal antibody seroconversion is not a sensitive measure of whether vaccine has boosted intestinal immunity; for such subjects, other measurements must be used. Study regimens in endemic areas should use a single 5 x 10(9) cfu dose.

Administration, Oral↗
PubMed1992

Antibodies to shiga holotoxin and to two synthetic peptides of the B subunit in sera of patients with Shigella dysenteriae 1 dysentery.

Acute- and convalescent-phase sera from 18 Thai patients and convalescent-phase sera from two Israeli patients and one Bangladeshi patient with Shigella dysenteriae 1 (Shiga) dysentery were tested by enzyme-linked immunosorbent assay to detect antibodies that bind S. dysenteriae lipopolysaccharide (LPS), Shiga holotoxin, or two synthetic peptides representing epitopes from the B subunit of Shiga toxin. Paired sera from 24 Maryland adults with Shigella flexneri 2a or Shigella sonnei diarrhea served as negative controls. Of the 16 paired Thai serum samples tested for immunoglobulin G LPS antibody, 10 had greater than or equal to 4-fold rises (the two subjects with the highest convalescent-phase titers exhibited toxin-neutralizing activity); acute-phase specimens from four of the remaining six individuals already had elevated Shiga LPS titers in their acute specimens ranging from 1:800 to 1:12,800. Similarly, convalescent-phase sera from the two Israeli patients and the Bangladeshi patient revealed LPS titers of 1:800 to 1:3,200. In contrast, none of the Maryland volunteers with S. flexneri or S. sonnei diarrhea manifested rises in Shiga anti-LPS (P less than 0.00001 versus 10 of 16 Thai patients). Only 4 of the 18 Thai patients had significant rise in antibody to purified Shiga toxin, while one of the two Israeli patients and the one Bangladeshi patient had elevated convalescent-phase titers. None of the sera that reacted with Shiga holotoxin had antibody that bound to the peptides. This report, which describes a search for serum antibodies that bind Shiga toxin in patients with Shiga dysentery, demonstrates such antibodies in only a minority of patients with bacteriologically confirmed disease. During Shiga dysentery, Shiga toxin may be elaborated in such small quantities in vivo that it fails to elicit an immune response in most patients even though it may exert biological effects. In this behavior Shiga toxin resembles tetanus toxin, another potent exotoxin that fails to elicit antitoxic responses in people who recover from clinical tetanus.

Adolescent↗
PubMed1992

Self-esteem, anxiety, and drug use.

This pilot study evaluated the relationship between self-esteem, anxiety, and drug use in a nonclinical sample of 30 men, ages 16 to 43 years, who completed and returned inventories on self-esteem, trait anxiety, and drug use which they had received by mail. Analysis showed a significant negative correlation between self-esteem and drug use and a significant positive correlation between trait anxiety and drug use. Also, a significant negative correlation was found between self-esteem and trait anxiety. Implications are discussed.

Adaptation, Psychological↗
PubMed1992

Perception of different frequencies of cranial transcutaneous electrical nerve stimulation in normal and HIV-positive individuals.

Sine-wave transcutaneous electrical nerve stimulation (TENS) of varying frequencies applied across the cranium (ear to ear) has been demonstrated to evoke three different noncutaneous sensations in three discrete, nonoverlapping frequency bands in normal, healthy subjects. This report describes two studies which evaluate perception of these cranial TENS-evoked, frequency-dependent sensations in normal and HIV-positive individuals. In Exp. I, all of 50 normal, healthy subjects reported perceiving the same three noncutaneous sensations in the same three nonoverlapping frequency bands as long as stimulated and over repeated trials. In Exp. II, 34 HIV-positive individuals (14 asymptomatic, 9 ARC, 11 AIDS) who were free of neurological symptoms differed significantly from 10 normal, healthy controls, and from the norms observed in Exp. I, on perception of the three different TENS-evoked sensations. Also, inability to maintain perception of the stimulus over repeated trials, observed only in the HIV-positive individuals, increased significantly with severity of HIV infection.

AIDS Dementia Complex↗
PubMed1992

Radioimmunoscintigraphy of metastatic breast carcinoma.

Seventeen patients with breast cancer underwent preoperative radioimmunoscintigraphy (RIS). Planar and tomographic imaging techniques (single photon emission computerised tomography--SPECT) were studied using Indium-111-labelled anti-epithelial membrane antigen (EMA) antibodies for tumour localisation. Overall imaging sensitivities were reasonable with correct identification of around 90% of primary lesions and 50% of secondary lesions. Planar imaging was more sensitive than SPECT for identification of superficial lesions such as the primary lesions (88% vs 56%) and axillary metastases (59% vs 53%). SPECT was necessary, however, for detection of deeper lesions such as internal mammary chain metastases and often served as an adjunct rather than an alternative to planar imaging. RIS, therefore, may contribute to more accurate staging of breast cancer, although further technical advances in RIS would enhance this contribution.

Adult↗
PubMed1991

Astroviruses as a cause of gastroenteritis in children.

BACKGROUND: Infection with astroviruses has been associated with gastroenteritis in children, and serologic surveys indicate that this infection may be frequent. The importance of astroviruses as agents of gastroenteritis has not been shown in a controlled study, however. METHODS: We used monoclonal antibody-based enzyme immunoassays to detect astroviruses, enteric adenoviruses, and rotaviruses in stool samples obtained from age-matched children with and children without gastroenteritis. The samples were obtained in two studies, three years apart, among patients attending an outpatient clinic in Bangkok, Thailand. RESULTS: In the first study, astroviruses were detected in 8.6 percent (96 of 1111) of the children with gastroenteritis and in 2.0 percent (19 of 947) of the children without gastroenteritis. In the second study the rates were 8.6 percent (50 of 580) and 2.1 percent (11 of 512), respectively. For both studies combined, enteric adenoviruses were detected in 2.6 percent of those with gastroenteritis and in 0.5 percent of the controls, whereas rotaviruses were detected in 19 percent of those with gastroenteritis and in 1.0 percent of the controls. The clinical findings associated with astrovirus infection were similar to those associated with rotavirus infection, except for a trend toward greater dehydration in the children infected with rotaviruses. CONCLUSIONS: These two controlled studies involving a total of 3150 Thai children provide evidence that astroviruses are a common cause of viral gastroenteritis. Astroviruses were found in association with gastroenteritis more frequently than were enteric adenoviruses, and with nearly half the frequency of rotaviruses.

Adenoviruses, Human↗
PubMed1991

Treatment of travelers' diarrhea: ciprofloxacin plus loperamide compared with ciprofloxacin alone. A placebo-controlled, randomized trial.

OBJECTIVE: To compare the safety and efficacy of loperamide used in combination with ciprofloxacin or ciprofloxacin alone for the treatment of travelers' diarrhea. DESIGN: Double-blind, placebo-controlled, randomized clinical trial. SETTING: United States Army hospital in Egypt. PARTICIPANTS: United States military personnel with travelers' diarrhea (n = 104) during a military exercise in November 1989. Persons who were noncompliant, had bloody diarrhea, or had received antidiarrheal medications before entry into the study were excluded. INTERVENTIONS: All participants with travelers' diarrhea were treated with ciprofloxacin, 500 mg twice daily for 3 days. Fifty of these patients were randomly assigned to receive loperamide, a 4-mg first dose and 2 mg for every loose stool (as much as 16 mg/d), and 54 were randomly assigned to receive placebo. MEASUREMENTS: Enterotoxigenic Escherichia coli was isolated from 57% of patients; Shigella and Salmonella, seen in 4% and 2% of patients, respectively, were not common. MAIN RESULTS: After 24 hours, the symptoms of 82% of patients in the ciprofloxacin and loperamide group compared with 67% in the ciprofloxacin and placebo group had improved or fully recovered (odds ratio, 2.3; 95% CI, 0.8 to 6.3; P = 0.08). After 48 hours, the symptoms of 90% of both groups had improved or fully recovered. The mean number of stools for those receiving loperamide was not much lower than those who did not receive loperamide after 24 hours (1.9 +/- 0.2 [SE] compared with 2.6 +/- 0.2) or 48 hours (3.1 +/- 0.3 compared with 4.0 +/- 0.3) of treatment (P = 0.19). CONCLUSIONS: In a region where enterotoxigenic E. coli was the predominant cause of travelers' diarrhea, loperamide combined with ciprofloxacin was not better than treatment with ciprofloxacin alone. Loperamide appeared to have some benefit in the first 24 hours of treatment in patients infected with enterotoxigenic E. coli. Both regimens were safe.

Ciprofloxacin↗
PubMed1991

Lack of immune response to the Vi component of a Vi-positive variant of the Salmonella typhi live oral vaccine strain Ty21a in human studies.

New typhoid vaccines have been sought to replace the reactogenic parenteral whole cell vaccines. Both Ty21a, a live oral attenuated Vi-negative Salmonella typhi vaccine strain, and parenteral Vi polysaccharide vaccine are safe and efficacious in field trials. To achieve potentially greater protective efficacy, a derivative of Ty21a that expresses Vi polysaccharide was prepared and its safety and immunogenicity assessed in 27 adult volunteers. The volunteers received either one dose of 5 x 10(5), 5 x 10(7), or 5 x 10(9) cfu or three doses of 5 x 10(9) cfu of lyophilized vaccine and were observed for adverse effects on a research isolation ward. The vaccine was well tolerated; however, at the highest dose, 13% of volunteers had mild diarrhea. Serial blood cultures were negative for the vaccine strain. Vaccine was shed in the stool of most volunteers at the higher doses for 1-4 days. No serum antibodies to Vi, circulating cells secreting antibody to Vi, or jejunal fluid antibodies to Vi were detected in any volunteer.

Adult↗