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Biomedical subjects

P Savage

Publications and source records attributed to P Savage.

13 recordsLinked to original sources
PubMed1992

Dual effects of endothelin-1 on neurite outgrowth induced by 12-O-tetradecanoylphorbol-13-acetate.

The vasoactive peptide endothelin-1 (ET-1) was found to bind to a single class of binding sites in chick embryonic sensory ganglia with a Kd of 67 +/- 5 pM. Treatment of ganglia explants with 100 pM ET-1 did not affect neuronal development, but when added together with 12-O-tetradecanoylphorbol-13-acetate (TPA) a synergistic stimulation of neurite outgrowth was observed. In contrast, 10 nM ET-1 inhibited TPA-induced neurite outgrowth. Both the stimulatory and inhibitory effects were not blocked by nifedipine, a Ca2+ channel blocker. These results suggest that ET-1 can modulate the process of neurite outgrowth and its effects are not dependent on voltage-gated Ca2+ channels.

Animals↗
PubMed1992

Identification and partial purification of a thiol endothelin-converting enzyme from porcine aortic endothelial cells.

Endothelin is a potent peptide vasoconstrictor. The final step in the processing of endothelin has been postulated to be the cleavage of the Trp21-Val22 peptide bond in proendothelin by a putative endothelin-converting enzyme. A soluble extract of primary porcine aortic endothelial cells was found to contain an enzyme activity that converted proendothelin-1 (proET-1) to an endothelin-1 (ET-1)-like peptide as determined by the rabbit aortic ring contraction assay. This enzyme was partially purified by DE52 ion-exchange chromatography. Incubation of proET-1 with the partially purified enzyme generated a product which had a retention time on HPLC identical to that of authentic ET-1. Further analysis of the product showed that it caused contraction of rabbit aortic rings, had a molecular weight identical to ET-1 as measured by fast atom bombardment mass spectrometry, and competed for [125I]ET-1 binding in an RIA using specific antibodies which recognize the carboxy terminal tryptophan of ET-1. The enzyme activity could be inhibited by thiol protease inhibitors such as Z-phe-pheCHN2 and p-hydroxymercuribenzoate, but not by serine- or metalloprotease inhibitors. The optimal pH for the enzymatic activity was between 7.0 and 7.5, and no activity was detected at pH 4.0. These results demonstrate that this thiol protease is a potential endothelin-converting enzyme.

Animals↗
PubMed1992

Decrease in immunoreactivity and vasoactivity of endothelin-1 after exposure to oxygen.

Endothelin-1 (ET-1) caused a dose-dependent contraction of porcine coronary arterial rings. Preincubation of ET-1 in oxygenated Krebs solution at 37 degrees C resulted in a progressive loss of the contractile activity and immunoreactivity of ET-1. The half-life of ET-1 contractile activity in oxygenated and non-oxygenated buffer was 16.1 and 86.6 min., respectively. The molecular weight of ET-1 exposed to oxygen was identical to that of ET-1. These results indicate that during the contraction of smooth muscle preparations the levels of ET-1 in the tissue bath are steadily decreasing due to exposure to high pO2 levels.

Animals↗
PubMed1992

Toxicity and pharmacokinetics of intravitreally injected ciprofloxacin in rabbit eyes.

To assess the toxicity of intraocular injection of ciprofloxacin, 22 New Zealand white rabbits received midvitreal injections of 100, 200, 400, 800 or 3200 micrograms of ciprofloxacin in 0.1 mL of distilled water (39 eyes) or 0.1 mL of distilled water only (5 eyes). The ocular pharmacokinetics of intravitreally injected ciprofloxacin was determined by aqueous humour and vitreous sampling 1, 2, 4, 8, 12, 18 or 24 hours after midvitreal injection of 100 micrograms of the drug in one eye each of 25 New Zealand white rabbits. The samples were analysed by means of a disc diffusion bioassay. No ocular damage was noted on ophthalmoscopy at any of the concentrations tested. Histologic study showed mild, transient vacuolation of the nerve-fibre layer in all eyes, including the control eyes, 2 hours after injection; at 24 hours no vacuolation was evident except at concentrations of 800 and 3200 micrograms, at which plexiform layer damage was evident. Peak aqueous and vitreous levels of ciprofloxacin were obtained at 1 hour (0.59 and 27.26 micrograms/mL respectively); the vitreous level fell to below 1.0 micrograms/mL 12 hours after injection. We conclude that intravitreally injected ciprofloxacin may be a safe and useful antibiotic in the treatment of aminoglycoside-resistant bacterial endophthalmitis.

Animals↗
PubMed1991

Patient assessment in psychiatric nursing.

This paper examines the literature on patient assessment in nursing, with particular reference to assessment in psychiatric nursing. It finds that most nursing assessment is concerned with gathering physiological information about patients while effectively ignoring psychosocial indices. This phenomenon, it is argued, is due to historical factors in the socialization of nurses, the particular version of nursing process imported into the UK, and an oversimplification of the concept of 'need' which has encouraged nurses to focus on patient disabilities but has ignored their capabilities. It is proposed that nursing assessment should be a relatively lengthy process, increasing in specificity, involving gathering and analysing information from a holistic perspective about individuals'/families' health concerns. Then, by applying concepts from appropriate conceptual models, a nursing diagnosis to those health concerns is proposed. This proposal is supported by a discussion of the process, functions and methods of nursing assessment. Finally, while recognizing the importance of social causation theories in psychiatric care, it is argued that community health assessments are beyond the scope of individual nurses.

Holistic Health↗
PubMed1990

The utility of indirect measures of obesity in racial comparisons of blood pressure. CARDIA Study Group.

The associations between estimates of obesity derived from anthropometric measurements (body mass index, the sum of three skin folds, and the computed percent body fat) and blood pressures were examined by multiple regression analysis in 4508 young black and white adults. The three estimates of obesity yielded similar results in regression analyses. The strength of associations between these three estimates of obesity and systolic and diastolic blood pressures did not differ in black and white subjects of either sex. All three estimates lead to the same interpretation of the relationship between obesity and systolic or diastolic blood pressure. Estimated percent body fat offered no advantage over the other indices in this context.

Adult↗
PubMed1990

Different affinities and selectivities of endothelin-1 and endothelin-3 binding to various rat tissues.

Inhibition of [125I]endothelin-1 ([125I]ET-1) binding to membrane fractions from various rat tissues by ET-1 and endothelin-3 (ET-3) was investigated. Brain tissue demonstrated a 37-fold higher affinity for ET-1 compared to lung, while a greater than 1000-fold difference in affinity for ET-3 was observed in these two tissues. Furthermore, the ratio of the IC50 value of ET-3 to that of ET-1 in each tissue varied from approximately 2 in brain, kidney and liver to greater than 100 in heart and spleen. These experiments show that the tissues examined have different affinities as well as different selectivities for ET-1 and ET-3.

Animals↗
PubMed1988

Chickenpox pneumonia: experience with antiviral treatment.

Of 13 patients with chickenpox pneumonia (12 of them adults) treated during 1979-87, 10 received antiviral drugs--nine acyclovir and one vidarabine. Three died despite intensive treatment. Serious secondary infections occurred in six cases. There were no clear indications that antiviral treatment altered the natural history of the condition. Acyclovir may at present be used too late in the course of chickenpox pneumonia to alter its outcome.

Acyclovir↗
PubMed1985

Long-term high fibre, low fat diet in gestational diabetes.

A 30-year-old Caucasian who developed gestational diabetes in her first pregnancy requiring 58 U insulin daily and who subsequently adopted a high fibre, low fat diet and who was able to maintain normal glucose tolerance throughout a second pregnancy is reported.

Adult↗
PubMedDate not supplied

Developing clinical decision-making skills in staff nurses; an educational program.

Clinical decision-making (CDM) is central to professional nursing practice. Use of this process enhances the nurse's ability to assess patients, to identify problems, and to plan individualized care. The Nursing Department at the Toronto General Hospital recognized that in order for nurses to effectively plan individualized care for their patients, they first needed help to develop their CDM skills. In response, a hospital-wide educational program was designed and implemented. This article describes the program and highlights the factors found to be crucial to its success. General recommendations are outlined for those who wish to design similar CDM skill-developing programs.

Clinical Competence↗