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Biomedical subjects

J Farmer

Publications and source records attributed to J Farmer.

78 records · Page 5Linked to original sources
PubMedDate not supplied

Pharmacokinetics and pharmacodynamics of enalapril in patients with congestive heart failure and patients with hypertension.

The clinical pharmacokinetics and pharmacodynamics of enalapril and its de-esterified active metabolite, MK 422, were determined in eight patients with congestive cardiomyopathy and five patients with hypertension. After administration of single doses of 2.5, 5, and 10 mg enalapril in the congestive heart failure patients and 20 or 40 mg in the hypertensive patients, serum levels and urine elimination of enalapril and MK 422 were determined. Standing and supine heart rate and blood pressure were measured as was ejection fraction in the congestive heart failure group and renin activity, aldosterone levels, and converting enzyme activity in the hypertensive group. Apparent oral clearance after administration of 5 and 10 mg enalapril was lower in the congestive heart failure patients (0.6 +/- 0.2 and 0.7 +/- 0.4 L/min) than after 20 and 40 mg given to hypertensive patients (2.5 +/- 1.3 and 2.7 +/- 2.7 L/min). The elimination of MK 422 was also slower in the congestive heart failure patients (7.8 +/- 5.0 and 6.8 +/- 2.5 h after 5 and 10 mg enalapril, respectively, vs. 4.6 +/- 2.0 and 5.3 +/- 1.1 h after 20 and 40 mg, respectively, in the hypertension group). The enalapril area under the concentration-time curve increased disproportionately to dose increments in both groups, but was more pronounced in congestive heart failure. Twenty and 40 mg enalapril lowered the blood pressure by 2 h after dosing in the hypertension group, and peak effects were seen 4-5 h after dosing. Peak effects correlated with peak serum MK 422 concentrations but not with enalapril (MK 421) levels. Supine heart rates were unchanged after 20 mg, but increased after 40 mg; standing heart rates were transiently increased after 20 and 40 mg enalapril. Blood pressure was not significantly changed in the congestive heart failure group, and cardiac ejection fraction was unchanged. In the hypertension group, renin stimulation and converting enzyme activity inhibition were seen at 4 h and persisted for at least 24 h after administration of 40 mg enalapril. In summary, the clearance of enalapril and elimination of MK 422 was slower in congestive heart failure patients versus hypertensive patients. Therefore, slower onset and longer duration of drug effect might be anticipated in patients with congestive heart failure versus patients with hypertension during enalapril administration.

Adult↗
PubMedDate not supplied

Effects of hypobaric pressure on the labyrinth. Cochlear aqueduct patent.

Cats with the cochlear aqueduct patent were placed in a pressure chamber and exposed for 10 min to hypobaric pressures of 5.1 and 6.8 kPa relative to atmospheric pressure. The experiments were designed according to a program used for treatment of Meniere's disease. The perilymph, middle ear, cerebrospinal fluid (CSF), venous, arterial and chamber pressures were recorded. The results demonstrated that hypobaric effects on the labyrinth were mediated via pressure changes in the middle ear and not via a systemic vascular or CSF influence. A reduction in chamber pressure induced a relative increase in middle ear pressure. It was the rate of the hypobaric change as well as the patency of the cochlear aqueduct and the Eustachian tube function that determined the magnitude of the initial perilymph peak pressure and the duration of this pressure increase. A rapid versus a slow rate induced an initial perilymph increase of 3.4 and 2.2 kPa, respectively. This relative pressure increase was eliminated within 1 min via the patent aqueduct. Thus, neither did a longstanding perilymph pressure increase occur during the hypobaric exposure, nor did a prolonged significant reduction in perilymph pressure occur after atmospheric pressure was restored.

Animals↗
PubMedDate not supplied

Are employees satisfied? A survey of occupational health services.

With stepped-up efforts to contain costs, there is widespread concern that medical facilities and insurance carriers are not paying enough attention to accident prevention. This recent study of occupational health services reveals that patients supported by private insurance appear to be less than satisfied with the quality of care when they are treated for work-related injuries or illnesses in industrial clinics. However, when a health or safety consultant is on staff, patient attitudes improve markedly. There is clearly an increasing role for health educators in facilitating a better understanding among patients of industrial medical resources.

Accidents, Occupational↗
PubMedDate not supplied

Survey and workshop initiative on community nurses' knowledge of the Internet.

Information technology in the nursing profession has been in existence for years, but only now with the growing presence of the Internet is it viewed as a possible platform to help meet the need for nurses' continuing educational development. For this to happen, it is important to know qualified nurses' experience with the Internet. In the United Kingdom, there is little understanding of whether community nurses have experience in using the Internet and if they do, how they use it. This article reports the findings of a survey questionnaire, taken in 1998, that was designed to target a random sample of 100 community nurses in Aberdeen, Scotland, to gauge awareness and attitudes toward the use of electronic sources of information for continuing education purposes. The response rate for the questionnaire was 83% (n = 83). A series of workshops was also undertaken, exploring the potential of the Internet and its access. A total of 52 people attended the workshops. One of the main aims of the workshops was to demystify the image of the computer, breaking down barriers for those with little or no experience in this field. The major findings of the survey and workshops indicate that although many respondents were interested in the potential benefits of the Internet to access information, there was little use made of and limited access to computer equipment.

Adult↗
PubMedDate not supplied

In vivo inhibition of chicken brain acetylcholinesterase and neurotoxic esterase in relation to the delayed neurotoxicity of leptophos and cyanofenphos.

An equimolal single dose (1 mmole/kg) of leptophos or cyanofenphos was given orally to chickens to assay the clinical and biochemical neurotoxic effects of these two organophosphorus insecticides. Parathion and TOCP at 2 and 1000 mg/kg of chicken body weight were tested in the same manner as negative and positive neurotoxicants, respectively. Three birds of each of five groups tested were sacrificed 1,2,3,7,14,21 and 28 days after treatment and the brains were taken for the biochemical tests. Acetylcholinesterase (AChE) and neurotoxic esterase (NTE) activities were determined in the brain microsomal fractions. In addition, the AChE activity in the brain soluble fractions was measured. Clinical observations indicated that leptophos-, cyanofenphos- and parathion-treated chickens became acutely poisoned but recovered from the typical cholinergic signs in a day or two. However, about 10 to 15 days later leptophos- and cyanofenphos-treated chickens developed the characteristic leg weakness and unrecoverable ataxia seen in birds given TOCP. The biochemical results indicated that cyanofenphos followed by leptophos and parathion produced more in vivo AChE inhibition than that produced by TOCP in both chicken brain soluble and microsomal fractions. Results suggested that there are no correlations between the in vivo effect of TOCP, leptophos and cyanofenphos on AChE and phenyl valerate-total hydrolyzing activities and the ability of these chemicals to produce neuropathy in hens. The results obtained from this study of the in vivo effect of the tested compounds on chicken brain NTE activity present an acceptable correlation between the inhibition of this enzyme and the ability of these chemicals to induce neuropathy. The mechanism and explanation for this correlation are presented. The in vivo effect of the tested compounds on the chicken brain NTE activity was determined using the indirect and a new direct method. The data presented in this report suggested that the new direct technique of assaying NTE activity using 4-nitrophenyl valerate (4-NPV) as substrate, can be useful in the in vivo screening studies of organophosphates for their ability to induce neuropathy in hens.

Acetylcholinesterase↗