PubMed Health⌕ Search

Biomedical subjects

T J Keefe

Publications and source records attributed to T J Keefe.

At least 55 records · Page 3Linked to original sources
PubMed1985

Two-step estimators of the scale parameter of the Weibull distribution.

An efficient two-step method of estimating the scale parameter of the Weibull distribution is presented and compared to other estimation procedures. The shape parameter is obtained by a procedure other than maximum likelihood and then substituted into the maximum likelihood formula for the scale parameter. Three two-step and four one-step estimators were compared using a Monte Carlo simulation. When the shape parameter is less than one, the two-step estimator using a generalized least-squares estimate of the shape parameter was best in terms of observed relative efficiency. Maximum likelihood was best, but followed closely by the generalized least-squares estimator when the shape parameter is greater than one.

Biometry↗
PubMed1985

Amoxycillin and clavulanic acid combination in the treatment of experimentally induced bacterial cystitis in cats.

Clavulanic acid (CA) competitively inhibits beta-lactamase hydrolysis of penicillins in vitro. Treatment with amoxycillin combined with clavulanic acid (A-CA) was compared with placebo in a blind study in cats with experimental cystitis caused by Escherichia coli demonstrating in vitro resistance to amoxycillin. Bacterial cystitis was induced in 20 cats by bladder infusion of 5 ml of 0.05 per cent alcoholic salicylic acid followed after 24 hours by a brain-heart infusion broth of E coli (10(8) colony forming units ml-1) previously found to be resistant to amoxycillin in vitro (minimum inhibitory concentration over 512 micrograms ml-1). Four days after infection, cats were randomly divided into two groups of 10 and treated with amoxycillin combined with clavulanic acid or placebo for 10 days. When compared to the placebo-treated group, the A-CA treated group showed: reduced quantitative bacterial counts in urine on days 7 (P less than 0.001) and 14 (P less than 0.02); reduced culture positive urine on days 7 (P less than 0.001) and 14 (P less than 0.001); and less severe inflammation on histological examination of the bladder and urethra (P less than 0.01). It was concluded that A-CA was effective in reducing the bacterial count and reducing the histopathological changes in the bladder and urethra in an experimental model of acute bacterial cystitis in cats infected with an E coli demonstrating in vitro resistance to amoxycillin.

Amoxicillin↗
PubMed1984

Development of a mathematical model for predicting concentrations of small asbestos fibers.

The standard method of asbestos sample analysis by phase-contrast microscopy excludes fibers which are below the resolution limits of the light microscope. Electron microscopic studies revealed that fibers in these small size ranges comprise the majority of fibers in asbestos dust. This research was conducted to determine if the development of a mathematical model for predicting concentrations of small fibers (less than 5 microns length) based on phase-contrast concentrations was feasible. The model presented in this paper was evaluated for its practical utility and was determined to be of minimal value; however, it was felt that the development of a reasonably accurate model can be arrived at through continued research.

Asbestos↗
PubMed1983

Ticarcillin administration to the equine: Intrauterine and intramuscular.

Serum levels of ticarcillin disodium, a semi-synthetic penicillin (Beecham Laboratories, Bristol, Tennessee, 37620), were measured at various time intervals up to and including 24 h after intrauterine and intramuscular administration in adult female horses. Three separate studies were conducted in Part I: in the first and second studies, serum levels were measured after intrauterine administration of 1 and 3 g of ticarcillin, respectively, and in the third study, levels were measured after intramuscular administration of 6 g of ticarcillin. In Part II, serum levels of ticarcillin were measured after intramuscular administration of ticarcillin at dosages based on body weight: 10 mg/lb (22 mg/kg) of body weight, 15 mg/lb (33 mg/kg) of body weight and 20 mg/lb (44 mg/kg) of body weight. Results showed little if any absorption of the antibiotics into the systemic circulation after intrauterine administration. All serum levels measured after administration of both intrauterine dosages of 1 and 3 g were less than 4.0 ug/ml. Peak serum concentrations, after intramuscular administration of 6 g of ticarcillin, occurred between 20 and 45 min after administration and averaged 15.97 +/- 5.0 ug/ml. Average peak serum concentrations, after intramuscular administration of 10 mg/lb (22 mg/kg) of body weight, 15 mg/lb (33 mg/kg) of body weight, 15 mg/lb (33 mg/kg) and 20 mg/lb (44 mg/kg) of body weight, were 16.12 ug/ml, 25.75 ug/ml and 50.25 ug/ml, respectively. After intramuscular administration of 6 g of ticaracilin, average serum half-life was determined to be 2.9 h.

Journal Article↗
PubMed1982

Distribution of Ehrlichia canis among military working dogs in the world and selected civilian dogs in the United States.

Antibodies to Ehrlichia canis were detected by indirect immunofluorescence in sera from 233 of 2,077 (11%) military working dogs in various locations throughout the world and from 535 of 938 (57%) civilian dogs in the United States during a 1-year period of study. Overall, E canis infection rates ranged from 13% in the tropical and temperate zones below 45 degrees N to 8% in the cold zone north of 45 degrees N latitude. The highest antibody prevalence rate (24%) was found among a select population of dogs stationed between 40 degrees and 45 degrees north latitude (Japan and Okinawa). The seropositive military dogs did not have clinical signs of ehrlichiosis, thus indicating that the predominant form of infection was subclinical. On the other hand, 216 (23%) of the seropositive civilian dogs had various signs of the disease. The difference was attributed to the fact that the sera from civilian dogs were submitted by practitioners who suspected the disease.

Animals↗
PubMed1981

National study of chlorinated hydrocarbon insecticide residues in human milk, USA. I. Geographic distribution of dieldrin, heptachlor, heptachlor epoxide, chlordane, oxychlordane, and mirex.

Human milk samples obtained from 1436 women residing in the United States were analyzed by gas-liquid chromatography for the chlorinated hydrocarbon insecticides--dieldrin, chlordane, heptachlor, heptachlor epoxide, oxychlordane and Mirex. Dieldrin was found above the detection limit (1.0 ppb) in over 80% of all the samples collected. Chlordane was not found in any of the 1436 milk samples but its metabolite, oxychlordane, was found above the detection limit in 74% of the samples. Although heptachlor was recovered in less than 2% of the samples, its metabolite, heptachlor epoxide, was found above the detection limit in 63% of the samples. It was of considerable interest that Mirex was not positively identified in any of the samples. The proportion of samples with values above the detection limit for dieldrin, heptachlor epoxide and oxychlordane varied significantly among the five geographic regions with the southeastern United States having the highest mean residue level for each of these three contaminants. For the United States the mean fat adjusted residue levels of those samples above the detection limit were 164.2 ppb for dieldrin, 91.4 ppb for heptachlor epoxide, and 95.8 ppb for oxychlordane.

Adult↗
PubMed1980

Enzyme-linked immunosorbent assay for evaluation of antibody to canine distemper virus.

An enzyme-linked immunosorbent assay (ELISA) for canine immunoglobulin (Ig) G antibodies to canine distemper virus (CDV) was developed and its test results were compared with those of the serum-neutralization (SN) test. The sera of 273 random-source adult dogs were examined. The two tests had a high degree of correlation. Very few discrepancies occurred and most of these were at the lower limits of each test. When the sera were tested at 1:100 dilution, there was a 98% agreement between the ELISA and SN test. Titrated SN and IgG ELISA tests also were performed on sera from 77 dogs whose lifetime medical histories were known. The results showed excellent agreement between the tests. Only five of the 77 sera showed any discrepancies and these were at detection-threshold levels. To follow antibody development in two dogs experimentally infected with CDV, it was necessary to use an ELISA which detected both canine IgM and IgG. The ELISA detected CDV-specific IgM a week before the SN test results became positive. The IgM titers rose for 3 weeks and descended to lower levels about the 4th and the 5th weeks. The SN titers closely followed the IgM titers. The ELISA detected IgG antibody about the 5th and the 6th weeks of infection. Results of both the SN test and the IgG ELISA remained elevated through the 70th day of testing.

Animals↗
PubMed1979

Studies of respiratory disease in random-source laboratory dogs: viral infections in unconditioned dogs.

A prospective study was conducted to identify the viruses causing respiratory diseases in unconditioned, random-source dogs. During the quarantine period, respiratory disease occurred in 86 of 167 (52%) dogs, and 34 (21%) died. Most affected dogs had a distemper-like illness which required extensive and prolonged care. Histopathologic studies confirmed the diagnosis of canine distemper in 10 of 12 (83%) fatal infections examined. Sixty-seven of 91 (74%) dogs which arrived without canine distemper antibody became ill, and 30 (32%) died. In contrast, only 16 of 67 (24%) dogs with canine distemper antibody had respiratory disease, and only 3 (4%) died. Parainfluenza SV5 and canine adenovirus--type II were recovered from 27 of 54 and 22 of 54 sick dogs, respectively. Canine herpesviruses, canine coronaviruses, and canine parvoviruses were less frequently isolated. Increased antibody titers to SV5 were found consistently, and rises in titer to the other viruses were demonstrated. Many of the sick dogs were infected with two or more viruses. Although several viral agents were detected during these epizootics, prevention of canine distemper appeared to be the key to controlling severe, prolonged, and often fatal respiratory disease.

Adenoviridae↗
PubMed1979

An enzyme-linked immunosorbent assay for the detection of canine antibodies to canine adenoviruses.

An enzyme-linked immunosorbent assay was used to detect canine immunoglobulin G antibodies specific for infectious canine hepatitis virus and the serologically related canine adenovirus Type 2. The sequential development of homologous and heterologous antibodies was measured by the enzyme-linked immunosorbent assay and serum neutralization tests in two groups of dogs which were experimentally infected with either infectious canine hepatitis virus or canine adenovirus Type 2. Both tests were comparable in their abilities to detect the development of homologous and heterologous antibodies. Homologous antibodies were detected earlier and to a higher titer in both tests. There was a 98% agreement between the serum neutralization test and the enzyme-linked immunosorbent assay when sera from 224 random-source dogs were examined for infectious canine hepatitis virus antibodies. The enzyme-linked immunosorbent assay was found to be a highly efficient and rapid test to determine the immune status of dogs to infectious canine hepatitis virus and canine adenovirus Type 2.

Adenoviridae↗
PubMed1977

Detection and definition of canine intestinal carbohydrases, using a standardized method.

Intestinal mucosa and pancreas from purebred Beagle dogs were assayed for carbohydrase activity, using several methods of tissue treatment. The enzymes found and studied were alpha-amylase, sucrase, lactase, amyloglucosidase, cellobiase, maltase, and isomaltase. Experiments using polyacrylamide gel columns and heat inactivation showed the presence of an isozyme of maltase which degrades isomaltose. This activity had not been previously demonstrated in dogs. An optimal standard procedure is presented for the preparation and assay of canine digestive enzymes. A statistical analysis of variance of the results showed that the variance was primarily associated with differences among dogs and not by variance within the procedure. When the different extraction procedures were used, results indicated that the level of enzymes detected differed with the method of treatment.

Amylases↗
PubMed1975

Ecology of California encephalitis viruses on the Del Mar Va Peninsula. I. Virus isolations from mosquitoes.

The ecology of California encephalitis viruses was studied on the Del Mar Va Peninsula. Adult mosquitoes were collected weekly from May to October of 1971 and monthly from May to October of 1972, using CDC miniature light traps with Dry Ice. Floodwater mosquitoes were assayed for virus in suckling mice or cell cultures. In 1971 over 77,000 mosquitoes were processed, resulting in 33 virus isolations. In 1972, over 106,000 were processed and 63 virus strains were recovered. Of the 1971 strains, all but one were recovered from Aedes atlanticus mosquitoes, and of the 1972 strains all but two were recovered from A. atlanticus. All A. atlanticus strains were neutralized by Keystone virus mouse hyperimmune ascitic fluid (MHAF). All other strains were recovered from A. canadensis mosquitoes. The single 1971 strain, and one strain from 1972, were neutralized by Jamestown Canyon MHAF. The remaining strain was neutralized by Keystone MHAF. The rate of virus recovery from A. atlanticus remained approximately the same, both between years and during each year studied, even during periods when large numbers of adults were emerging, suggesting that these mosquitoes had emerged infected.

Animals↗