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Biomedical subjects

W P Green

Publications and source records attributed to W P Green.

15 recordsLinked to original sources
PubMed1992

Effects of diet on plasma concentrations of oral anthelmintics for cattle and sheep.

Groups of parasite-free lambs and calves which were either housed and fed hay and concentrates or were grazing on pasture were dosed separately with the oral anthelmintics fenbendazole and ivermectin (lambs only). The plasma concentrations of the drugs and their major metabolites were monitored during the period of their metabolism and excretion. The peak plasma concentrations and the availability of the drugs, as estimated by the areas under the plasma concentration-time curves, were significantly less in the grazing animals. When similar groups of lambs were dosed orally with the inert marker chromium EDTA, which has a particle size similar to the anthelmintics, it was observed that a higher percentage of chromium was excreted by the grazing lambs during the first 40 hours after dosing, suggesting that the extent of absorption in the grazing animals was less than in the housed animals.

Administration, Oral↗
PubMed1990

Comparison of the efficacy of dermal formulations of ivermectin and levamisole for the treatment and prevention of Dictyocaulus viviparus infection in cattle.

Four groups of six parasite-naive calves were infected at seven day intervals with three doses of infective larvae of Dictyocaulus viviparus. Twenty-one days after the first dose three of the groups were treated either with an injectable formulation of ivermectin at a dose rate of 200 micrograms/kg bodyweight, or with pour-on preparations of levamisole at 10 mg/kg or ivermectin at 500 micrograms/kg. On day 28 two calves from each group were slaughtered and their burdens of lungworms counted. On day 35 the remaining calves were reinfected with D viviparus infective larvae at a rate of 80 L3/kg. The levamisole preparation was 94.6 per cent effective and both ivermectin preparations were 100 per cent effective against the initial infections. The ivermectin-treated calves were protected from the reinfection which subsequently became patent in the levamisole-treated and control calves.

Administration, Topical↗
PubMed1990

A comparison of interactions between vaccination against Dictyocaulus viviparus and anthelmintic suppression in immunised and unimmunised yearling cattle.

Twenty parasite-naive calves aged approximately four months were divided randomly into four groups of five. Two groups were treated with oral lungworm vaccine. One immunised group plus another non-immunised group were put out to graze on May 1 on a pasture known to be contaminated with Dictyocaulus viviparus infective larvae during the previous autumn. All the calves both indoor and outdoor were treated with ivermectin at three, eight and 13 weeks after the first groups started to graze and again at housing at the end of September. After the winter housing period on April 27 of the following year all the calves were given an artificial challenge of D viviparus infective larvae at the rate of 15 larvae per kg bodyweight, and the clinical and parasitological reactions monitored. All the calves which had been vaccinated or exposed to field infection during year 1 reacted strongly in ELISAs using antigen prepared from fourth stage D viviparus larvae but much less strongly in similar tests using adult derived antigen. Clinically those calves exposed to previous field infections were less severely affected than the housed calves, although parasitologically all three groups with prior exposure to D viviparus appeared to have a similar functional level of immunity to the challenge infection in comparison to the unexposed calves of the same age.

Animals↗
PubMed1989

Efficacy of a homoeopathic prophylaxis against experimental infection of calves by the bovine lungworm Dictyocaulus viviparus.

Two groups of parasite-free calves, one of which had been treated with four doses of a homoeopathic oral vaccine for parasitic bronchitis due to Dictyocaulus viviparus and the other with a placebo, were infected at the rate of 25 infective larvae/kg bodyweight 18 days after the final dose. Both groups became severely affected by parasitic bronchitis, with clinical signs starting 13 days after infection. There were no discernible differences between the treated and control groups in their manifestations of resistance to D viviparus or their clinical responses to the disease produced.

Animals↗
PubMed1988

Immunity to parasitic bronchitis of yearling cattle treated with ivermectin during their first grazing season.

A group of 12 winter-born calves was divided into two groups of six. During the following summer one group grazed on pasture infected with Dictyocaulus viviparus, and was treated with ivermectin injections at three, eight and 13 weeks after turn out. The other group remained housed. Both groups were housed during the winter and then together with a group of younger calves were challenged with a trickle infection of D viviparus larvae at the rate of 25 third stage larvae/kg bodyweight for one month and then slaughtered. The group which had been exposed to previous infection was least affected by parasitic bronchitis and on the basis of serological titres and worm burdens had developed resistance to the challenge infection. The other older group was also more resistant than the younger calves.

Animals↗
PubMed1988

Efficacy of a levamisole bolus in field infections of bovine nematodes.

Forty four parasite free calves were divided into eight groups, four of six and four of five calves. Two of the groups of six were given a bolus containing 22 g of levamisole in a formulation designed to release the anthelmintic for ninety days. One group of treated calves was put out to graze at the beginning of May with one of the untreated larger groups on a field contaminated with O ostertagi and C oncophora, and the other treated group grazed with controls on a field known to have the same species plus D viviparus. On mid August these resident calves were removed, slaughtered and worm counts estimated. At the same time, the other groups of untreated calves were put onto the same fields to act as tracers of the level of infection. After grazing for one month they were housed, slaughtered and worm counts carried out. The faecal egg counts of treated calves were much less than those of the controls until the end of July. Control calves on the paddock infected with lungworm were severely affected by parasitic bronchitis whereas treated calves although infected did not display clinical symptoms. In the resident calves, O ostertagi burdens were reduced by 65 and 67% and C oncophora by 97% compared to untreated controls. In the tracer calves, there was no difference in burdens of O ostertagi and D viviparus but large differences in the number of C oncophora established.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1986

Comparison of vaccination and ivermectin treatment in the prevention of bovine lungworm.

Three groups of calves were put out to graze on separate paddocks within a field known to be infected with Dictyocaulus viviparus and were also given a small initial trickle infection of the parasite. The first group were untreated controls, the second were immunised with live irradiated lungworm vaccine and the third were injected three times with ivermectin; the injections taking place after they had grazed for three, eight and 13 weeks. The subsequent infections of D viviparus were estimated by grazing a series of parasite-free tracer calves in the paddocks used by each group. The first group of such calves grazed from July 17 until August 7, the second from August 22 to September 29. During the first half of the grazing season all the untreated and three of the six immunised calves were observed to excrete D viviparus larvae, in contrast to none of the ivermectin-treated group. As a result all the tracer calves on the areas occupied by the untreated and immunised calves became infected with the parasite whereas only one worm was found in one of the 10 tracer calves grazing the area occupied by the ivermectin-treated calves.

Animals↗
PubMed1986

Values and CPR decisions: a comparison of physicians and administrators in training.

A report of a study to analyze the effect of sociocultural patient characteristics (age, terminal diseases, drug abuse, alcoholism, mental retardation, dementia, suicide attempts, institutionalization, noncompliance with medical regimens, violent crimes, lack of support system, or relationship to a staff physician) on decisions to initiate or withhold cardiopulmonary resuscitation in an emergency situation. Pairs of vignettes were presented to residents in internal medicine and graduate students in an MBA program for comparisons of physicians' decisions with administrators' decisions. On some patient characteristics there were significant differences between the two groups. For most factors (drug abuse, multiple suicide attempts, age, violent crime, lack of known support systems, and relationship to staff), doctors are more likely to initiate CPR than are business students representing health care administrators. In chronic, long-term situations (carcinoma or heart disease, dementia, mental retardation, and institutionalization), the doctors are less likely to initiate CPR than the business students. If objectivity is a goal in deciding whether or not to initiate CPR, physicians should be aware of differences between their opinions and others'.

Decision Making↗
PubMed1985

Cardiopulmonary resuscitation. Values and decisions--a comparison of health care professionals.

The authors studied the effect of various patient factors (biomedical, mental status, and psychosocial) on the decision to perform cardiopulmonary resuscitation by internal medicine house staff and registered nurses. Clinical vignettes were utilized to assess the likelihood of initiation of cardiopulmonary resuscitation (CPR) by the respondents. In most cases, these factors had similar significant effects on decisions to initiate CPR by both physicians and nurses. However, some differences in the likelihood of performing CPR were found between the physician and nurse populations, particularly in the areas of mental status and institutionalization. Dementia, mental retardation, and nursing home status all caused residents to be significantly less likely to initiate CPR than nurses (P less than 0.001). This study demonstrates that biomedical, mental status, and psychosocial patient factors have a significant impact on the decision to initiate CPR by both internal medicine residents and nurses. These decisions apparently are rooted in similar criteria, although the basis for the differences between the two groups warrants further study.

Adult↗