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Biomedical subjects

A Williams

Publications and source records attributed to A Williams.

At least 397 records · Page 22Linked to original sources
PubMed1993

Inhibition of nitric oxide synthesis attenuates pressure-induced natriuretic responses in anesthetized dogs.

Inhibition of nitric oxide (NO) synthesis by intrarenal administration of nitro-L-arginine (NLA) leads to decreases in urinary sodium excretion (UNaV) in association with the increases in renal vascular resistance (RVR). In the present study, we examined the ability of the kidney to alter its sodium excretion in response to acute changes in renal arterial pressure (RAP) in anesthetized dogs before and during intrarenal infusion of NLA (50 micrograms.kg-1.min-1). NO synthesis inhibition in 11 dogs increased RVR by 32 +/- 4% and decreased renal blood flow (RBF) by 25 +/- 3%, outer cortical blood flow by 25 +/- 6%, urine flow by 37 +/- 14%, UNaV by 71 +/- 5%, and fractional excretion of sodium (FENa) by 71 +/- 4%. Glomerular filtration rate was not significantly changed during NLA infusion. As previously reported, there was suppression of the RBF autoregulation plateau during NO synthesis inhibition. In addition, there was a marked attenuation of urine flow and UNaV responses to reductions in RAP (150 to 75 mmHg), with significant reductions in the slopes of the relationships between RAP vs. UNaV and RAP vs. FENa during NLA infusion. Similar responses were observed in nine other dogs treated with the angiotensin receptor antagonist losartan, indicating that an augmented activity of the renin-angiotensin system is not responsible for attenuation of the slope of the pressure-natriuresis relationship during NLA infusion. These data suggest that NO may participate in the mediation of the pressure-natriuresis response.

Animals↗
PubMed1993

Renal responses to intra-arterial administration of nitric oxide donor in dogs.

Inhibition of nitric oxide synthesis by intra-arterial administration of nitro-L-arginine (NLA) leads to attenuation of the slope of the relation between renal arterial pressure (RAP) and sodium excretion without an alteration in renal autoregulatory efficiency. In the present study, we examined whether only the presence of nitric oxide or, alternatively, changes in nitric oxide production during changes in RAP are required for pressure natriuresis to occur. Anesthetized sodium-replete dogs (n = 8) were treated with NLA (50 micrograms.kg-1 x min-1) to inhibit endogenous nitric oxide formation, and S-nitroso-n-acetylpenicillamine (SNAP) was infused intra-arterially at a constant rate (2 micrograms.kg-1 x min-1) to replenish intrarenal nitric oxide levels. Renal responses to reductions in RAP within the autoregulatory range were assessed before and during NLA infusion followed by SNAP+NLA infusion. As reported previously, NLA infusion alone increased renal vascular resistance and decreased renal blood flow, urine flow, sodium excretion, and fractional excretion of sodium, with no change in glomerular filtration rate. Autoregulatory efficiency remained intact, whereas the pressure-induced natriuretic responses were attenuated. During SNAP+NLA infusion, renal blood flow increased from 2.8 +/- 0.3 to 3.5 +/- 0.3 mL.min-1 x g-1 (P < .001), without significant changes in glomerular filtration rate (0.75 +/- 0.07 to 0.81 +/- 0.05 mL.min-1 x g-1); the autoregulatory efficiency of renal blood flow and glomerular filtration rate remained intact. SNAP increased urine flow (4.8 +/- 1.8 to 10.0 +/- 2.5 microL.min-1 x g-1), sodium excretion (0.63 +/- 0.26 to 1.70 +/- 0.37 mumol.min-1 x g-1), and fractional excretion of sodium (0.55 +/- 0.20% to 1.38 +/- 0.27%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

A randomised trial of cyclophosphamide with and without low dose alpha-interferon in the treatment of newly diagnosed myeloma.

The role of alpha-interferon (IFN) in initial treatment of multiple myeloma is controversial. We have conducted a trial of cyclophosphamide with and without low dose IFN in newly diagnosed myeloma. Thirty four patients, mean age 63 were all given cyclophosphamide 600mg/m2 IV every 21 days while 17 were randomised to also receive IFN at a dose equivalent to 6mU per week. In the IFN group 8/15 assessable patients (53%) had a greater than 50% reduction in paraprotein compared with 4/16 (25%) of controls (p < 0.05). However the median duration of response was the same in the two groups (IFN 8 months, controls 8.5 months). After a median follow up of 28 months there is no significant difference in survival. Toxicity including myelosuppression was commoner in the IFN group. These findings suggest that the addition of IFN to cyclophosphamide is not likely to offer major benefits in treating myeloma.

Adult↗
PubMed1993

Community health learning experiences and political activism: a model for baccalaureate curriculum revolution content.

Nursing education is involved in a curriculum revolution that decries behaviorist theory. One model for the new educational approaches is political activism that involves faculty and students in experiences of caring client advocacy. Content, theory, and experiences in community-health nursing integrate community activism and sociopolitical concepts. Sample approaches that blend curriculum revolution and political activism concepts are included. Such approaches can easily be used as part of the lived experience of community-health nursing education.

Community Health Nursing↗
PubMed1993

Indirect discrimination and breast screening.

Uptake of screening services in inner-city communities has been low, particularly in older age groups, lower social classes, and ethnic minorities. In Leicester City, where up to 25% of the population belong to ethnic minorities, this may have important implications for breast screening. We randomly sampled 701 inner-city women aged 45 to 64 years, stratified by neighborhood and by women's "likely home language." Trained interviewers succeeded in interviewing 79% of those eligible, and we report here a preliminary analysis of 413 respondents. Knowledge of breast cancer and screening varied markedly and significantly by actual language: 60.4% of English-speaking and 12.5% of non-English-speaking women correctly answered 10 or more questions (of 14) about breast cancer and screening (chi 2(1) = 89.884; P = .000). Despite that, 80% or more women stated their intention to attend for screening and assessment if necessary, irrespective of neighborhood, language, age, or social class. We suggest that the difference in knowledge between language groups arose from indirect discrimination in the way in which health-related information is disseminated in British society. However, after providing appropriate screening information, we report similarly high intended acceptance rates in the two language groups.

Asia↗
PubMed1993

Effects of neck position on intracranial pressure.

OBJECTIVE: To investigate the effects of four nonneutral neck positions on intracranial pressure. DESIGN: An alternating treatment design was used to investigate the effect on intracranial pressure of rotation of the head to the left and right, neck flexion and neck extension. Each experimental position was separated by a neutral recovery period. SETTING: Neurological intensive care units in two tertiary care centers in the southwestern United States. SUBJECTS: Ten patients whose intracranial pressure was being therapeutically monitored but who were not experiencing prolonged periods of elevated intracranial pressure. PROCEDURE: Each neck position was maintained manually by the research staff for 5 minutes. Intracranial pressure was recorded at 1-minute intervals throughout the 45-minute data collection period. RESULTS: Rotating the head to the right and left and placing the neck in flexion resulted in significantly higher intracranial pressure readings than the baseline neutral neck position or positioning the neck in extension. The highest individual intracranial pressures always occurred with the head and neck rotated or in flexion. CONCLUSIONS: These data support previous studies that indicated that a patient at risk for pathological increase in intracranial pressure should not be positioned with the neck in flexion or the head turned to either side.

Adult↗
PubMed1993

A case for emotional support and human contact. Management of cardiogenic shock.

1. Cardiogenic shock is a state of acute circulatory failure precipitated by extensive left ventricular damage. 2. Nursing care of patients with cardiogenic shock must treat the 'whole person', and incorporate such elements as maintaining a safe environment; effective communication; nutrition and mobility. 3. Cardiogenic shock has a high mortality rate and is, therefore, very distressing for patients. Nursing care must ensure all patients are treated with respect and dignity.

Anxiety↗
PubMed1992

Studies on maternal transmission of scrapie in sheep by embryo transfer.

The technique of embryo transfer was used to investigate the maternal transmission of scrapie in sheep. Embryo donor ewes were experimentally infected with scrapie (all eventually developing the disease) and artificially inseminated six months later with semen from an uninfected scrapie-susceptible ram. Embryos were harvested five and six days after insemination and transferred by laparoscopy, unwashed, into recipient ewes which had been genetically selected for very low susceptibility to scrapie. Six of the 26 lambs born to these recipients developed scrapie.

Animals↗
PubMed1992

A scoring system for lung function tests in infants.

Measurements of thoracic gas volume (TGV), airway resistance (Raw), and airway conductance (Gaw) were calculated in a group of 42 normal infants using a whole-body plethysmograph. Maximum expiratory flow at functional residual capacity was measured in a separate group of 108 normal infants. Using data obtained from these infants the following regression equations were calculated: Gaw (L.s-1.cmH2O) = -0.0475 + 0.00164 x length (cm) square root of TGV (mL1/2) = -3.22 + 0.263 x length (cm) VmaxFRC (mL.s-1) = -173 + 5.2 x length (cm). The standard errors of prediction are a measure of the scatter of individual results from the normal population about the true regression line. They were used to define limits of the normal ranges for these tests of lung function, and to develop a scoring system. This approach is preferable to expressing results as percent predicted, which gives no indication of how likely a measurement is to be within normal limits.

Age Factors↗
PubMed1992

Ultrastructural features of spongiform encephalopathy transmitted to mice from three species of bovidae.

The ultrastructural neuropathology of mice experimentally inoculated with brain tissue of nyala (Tragelaphus angasi; subfamily Bovinae), or kudu (Tragelaphus strepsiceros; subfamily Bovinae) affected with spongiform encephalopathy was compared with that of mice inoculated with brain tissue from cows (Bos taurus; subfamily Bovinae) with bovine spongiform encephalopathy (BSE). As fresh brain tissue was not available for nyala or kudu, formalin-fixed tissues were used for transmission from these species. The effect of formalin fixation was compared with that of fresh brain in mice inoculated with fixed and unfixed brain tissue from cows with BSE. The nature and distribution of the pathological changes were similar irrespective of the source of inoculum or whether the inoculum was from fresh or previously fixed tissue. Vacuolation caused by loss of organelles and swelling was present in dendrites and axon terminals. Vacuoles were also seen as double-membrane-bound and single-membrane-bound structures within myelinated fibres, axon terminals and dendrites. Vacuoles are considered to have more than one morphogenesis but the structure of vacuoles in this study was nevertheless similar to previous descriptions of spongiform change in naturally occurring and experimental scrapie, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome and kuru. Other features of the ultrastructural pathology of the transmissible spongiform encephalopathies including dystrophic neurites and scrapie-associated particles or tubulovesicular bodies were also found in this study. Neuronal autophagy was a conspicuous finding. It is suggested that excess prion protein (PrP) accumulation, or accumulation of the scrapie-associated protease-resistant isoform of PrP, may lead to localised sequestration and phagocytosis of neuronal cytoplasm and ultimately to neuronal loss.

Animals↗
PubMed1992

Transposon mutagenesis in Legionella pneumophila. II.--Mutants exhibiting impaired intracellular growth within cultured macrophages and reduced virulence in vivo.

Transposon Tn5 mutants of L. pneumophila were isolated and screened for loss of virulence-associated characteristics. Three mutants were found with normal ability to produce putative pathogenicity determinants and to be endocytosed by guinea pig alveolar macrophages in vitro but with a greatly reduced ability to multiply within them. These mutants showed considerable loss of virulence in an authentic animal model of the pneumonia.

Animals↗
PubMed1992

Student mental health needs: survey results and implications for service.

In preparation for planning counseling and mental health services at Columbia University, the authors conducted a mental health needs assessment survey that sampled representative numbers of students. Respondents were most concerned about academic and school-related issues, followed by concerns in the area of love relationships. Multiple regression analysis revealed certain subgroups that were more likely to have these concerns and certain health and mental health problems that were significantly associated with these concerns. The study identified serious psychological problems, including suicidal/homicidal thoughts and sexual abuse, and surveyed respondents' treatment preferences. Finally, the authors discuss how the study findings contributed to sharpening and expanding focus on different aspects of program development in the collaboration between mental health and health education.

Adult↗