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Biomedical subjects

R A Wilson

Publications and source records attributed to R A Wilson.

318 records · Page 18Linked to original sources
PubMedDate not supplied

Lack of progressive "restrictive" physiology after heart transplantation despite intervening episodes of allograft rejection: comparison of serial rest and exercise hemodynamics one and two years after transplantation.

It has been suggested that the cardiac allograft becomes less compliant either because of repeated episodes of rejection, chronic hypertension, or as a direct consequence of immunosuppression. A corollary to this hypothesis is that this reduction in compliance should be a progressive, rather than a static, change. To test this hypothesis, rest and exercise filling pressures, cardiac outputs, and radionuclide ventriculographic systolic and diastolic indices were measured in 20 patients at 1 and 2 years after heart transplant by means of identical protocols at both study times. Between studies 10 of 20 patients had no rejection, five of 20 had one rejection episode, and five of 20 had more than one rejection episode. There were no significant differences in resting or exercise heart rates, pulmonary wedge pressures, cardiac outputs, left or right ventricular ejection fractions, left ventricular peak filling rates, or time to peak filling between the studies at 1 and 2 years. Only resting right atrial pressure increased between year 1 and year 2 (6 +/- 2 mm Hg vs 8 +/- 4 mm Hg, p = 0.035). These data demonstrate that cardiac allograft function is unchanged between 1 and 2 years after transplantation, despite episodes of intervening rejection and continued immunosuppression. The data further suggest that the previously reported decrease in cardiac allograft compliance does not appear to be caused by a progressive intrinsic abnormality in the allograft, and that other mechanisms for "restrictive" allograft physiology should be sought.

Adolescent↗
PubMedDate not supplied

An unusual second primary tumor. Report of a case of atypical carcinoid of the lung.

This case report presents a rare occurrence of two primary tumors in the same patient: a transitional cell carcinoma of the bladder and an atypical carcinoid of the lung. The time interval between a linear density and tumor growth to 3 cm, determined by chest radiographs, was 9 months. The rapidly growing pulmonary nodule was suspected to be a metastasis from the primary transitional cell carcinoma. Fine-needle aspiration revealed malignant cells. Lobectomy and light and electron microscopy revealed an atypical carcinoid. The definition of "atypical" requires revision to indicate this tumor's true potential.

Carcinoid Tumor↗
PubMedDate not supplied

A standardized enzyme-linked immunosorbent assay for infectious bronchitis virus: comparison with hemagglutination-inhibition and virus-neutralization assays for measuring protective antibody levels in chickens.

An enzyme-linked immunosorbent assay (ELISA) was developed to measure antibodies to infectious bronchitis virus (IBV) in chickens. The results are reported in IBV standard ELISA values calculated by comparing antibody levels in test sera with antibody levels in a series of standard reference sera. The IBV standard ELISA values were good indicators of responses to vaccination and the immune status of experimentally challenged birds. Although the assay was not serotype-specific, the sensitivity makes it ideally suited for determining the immune status of poultry flocks. The assay results compared favorably with other laboratory results, including virus-neutralization titers, hemagglutination-inhibition levels in sera, virus isolation from vaccinated/challenged birds, and the tracheal ring test results.

Animals↗
PubMedDate not supplied

Experimentally induced necrotic enteritis in chickens.

A 1.3 to 10% incidence of necrotic enteritis was experimentally produced in broiler-type chickens in three of five trials. The incidence range observed was considerably narrower and lower than the 5.6-37.3% range reported in the literature. Clostridium perfringens was inconsistently isolated from the liver and intestine of dosed chickens.

Animals↗
PubMedDate not supplied

In vitro and in vivo characterization of avian Escherichia coli. I. Serotypes, metabolic activity, and antibiotic sensitivity.

Over a 2 1/2-year period (January 1981 to June 1983), 177 Escherichia coli isolates were obtained from 145 field-reared broiler flocks in the Delmarva peninsula, and 20 were obtained from clinically normal day-old hatchery chickens representing an additional 17 flocks in Delmarva. Ninety-one isolates obtained from the field-reared birds between 2 and 8 weeks of age were associated with complicated air-sac disease. Serotyping efforts demonstrated a predominance of O2, O35, and O78 serogroups and a large number of untypable isolates. More than 50% of the isolates in each of the three dominant serogroups were collected from broilers with colibacillosis, but they were never detected in the yolk-sac samples of clinically normal day-old hatchery chickens. In vitro biochemical characterization of the E. coli isolates revealed variable rates of carbohydrate fermentation and amino acid decarboxylation. No common characteristics appeared to be shared by the predominant serogroups isolated from clinically affected birds, although several serogroup-specific reactions were noted. The majority of the isolates were sensitive to chloramphenicol, gentamicin, nalidixic acid, ormethoprim-sulfadimethoxine, spectinomycin, neomycin, and ampicillin. About half of the isolates were sensitive to nitrofurantoin and the sulfa compounds. Less than 25% of the isolates were sensitive to streptomycin, erythromycin, tetracyclines, novobiocin, penicillin, bacitracin, and lincomycin.

Animals↗
PubMedDate not supplied

In vitro and in vivo characterization of avian Escherichia coli. II. Factors associated with pathogenicity.

The pathogenicity of 197 Escherichia coli isolates obtained from clinically affected commercially grown broiler chickens and normal hatchery chicks was assessed by inoculating day-old broilers intratracheally. The degree of pathogenicity (high, intermediate, low) was judged according to mortality and lesions occurring within 7 days following inoculation. Serotype, metabolic activity, motility, and in vitro antibiotic sensitivity of each isolate were evaluated and related to pathogenicity. Seventy-five of the isolates of high to intermediate pathogenicity belonged to serogroup O2, O78, or O35. In addition, 51 pathogenic E. coli isolates could not be serotyped, and several had multiple serotypes. Most isolates had similar metabolic activity, as determined by amino acid decarboxylation and carbohydrate fermentation, regardless of pathogenicity. An exception was the fermentation of adonitol, which occurred more frequently with the highly pathogenic strains. Motility and in vitro antibiotic sensitivity were not related to pathogenicity. An age-associated resistance to intratracheal E. coli administration occurred by 15 days of age in uncompromised birds. Relative susceptibility of birds older than 2 weeks to intratracheal and/or intravenous E. coli inoculation could be increased by prior exposure to pathogenic reovirus 1733, adenovirus 3167, or infectious bursal disease virus (IBDV). Birds infected with IBDV at 3 weeks failed to clear apathogenic and pathogenic E. coli from circulating blood.

Aging↗
PubMedDate not supplied

An enzyme-linked immunosorbent assay that measures protective antibody levels to Newcastle disease virus in chickens.

An enzyme-linked immunosorbent assay (ELISA) was developed to measure antibodies to Newcastle disease virus (NDV) in chickens. Chickens 6 to 33 weeks old, with a variety of vaccination histories, were bled before challenge with a velogenic strain of NDV. Fourteen days post-challenge, 63 of the 73 challenged birds had survived. ELISA results of pre-challenge sera corresponded directly with survival rates of birds challenged with NDV.

Animals↗
PubMedDate not supplied

Characteristics of Escherichia coli isolates from avian cellulitis.

The purpose of this study was to characterize Escherichia coli isolates from avian cellulitis, particularly with respect to the occurrence of potential virulence factors. At slaughter, five broilers with lesions of cellulitis were selected from each of 20 farms from among the broilers processed. One hundred E. coli isolates from the lesions were characterized with respect to serotype; biotype; drug susceptibility; plasmid profile; ability to produce aerobactin, colicin, colicin V, and hemolysin; and cytotoxicity for Vero cells and chicken fibroblasts. The same properties were determined from a collection of 25 E. coli from the feces of chickens. Serotyping showed that, among the cellulitis isolates, 23 belonged to O group 78, 14 belonged to O2, eight belonged to O115, and seven belonged to O(21.83); 25 were untypable. Isolates from a single farm typically belonged to three to five O groups. More than half of the fecal isolates were untypable, and the rest were distributed among seven O groups. Biotype, drug-resistance pattern, and plasmid profile could not be used as markers of avian cellulitis E. coli. No plasmid was detected in 12% of cellulitis isolates and 48% of fecal isolates. No isolate was hemolytic or showed cytotoxic effects. Aerobactin was produced by 90% of cellulitis isolates, and colicin was produced by 85% of these isolates; the corresponding percentages for the fecal isolates were 16% and 40%. Production of colicin V was detected in 21% of cellulitis isolates and 24% of fecal isolates.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗