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Biomedical subjects

A Walker

Publications and source records attributed to A Walker.

At least 163 records · Page 9Linked to original sources
PubMed1996

Temperature dependence of release of vesicular content in bovine chromaffin cells.

Recent studies suggest that the time course of secretion of the vesicular content in bovine chromaffin cells is much slower than in the peripheral or the central nervous system, but the reasons for this marked difference are not known. In this study we try to assess the importance of factors that may influence the time course of release of the vesicular content of bovine chromaffin cells, namely: (1) diffusion of catecholamines in the extracellular solution, (2) dissociation of catecholamines from the matrix of chromogranin A, and (3) the kinetics of opening and closing of the fusion pore. The temperature dependence of the time course and the amplitude of the spontaneous current spikes were examined using the carbon filament recording technique in amperometric mode. The change in amplitude was not statistically significant, but both the rise and the decay times were shortened (from 29 +/- 12 to 16 +/- 5 ms, and from 87 +/- 26 to 57 +/- 11 ms respectively) as temperature was raised by 20 degrees C [from 15 to 35 degrees C; n = 6; the changes were statistically significant at the level of P = 0.05; their respective temperature coefficients (Q10) were 1.4 and 1.3]. The areas underneath the spontaneous current spikes, however, were not altered significantly. Neither the relationship between the rise and the decay times nor the frequency of occurrence of the spontaneous current spikes changed consistently as the temperature was raised. However, the frequency histograms could, in all cases, be well described by a monoexponential function. It is concluded that the release of catecholamine content from the individual vesicles in bovine chromaffin cells is probably mostly determined by the dissociation of catecholamines from the matrix of chromogranin A.

Adrenal Medulla↗
PubMed1996

Rethinking the western construction of the welfare state.

This article employs case studies of China and Hong Kong to question the western ethnocentric construction of the welfare state that predominates in comparative social policy research. The authors argue that welfare regimes, and particularly the "welfare state," have been constructed as capitalist-democratic projects and that this has the damaging effect of excluding from analyses not only several advanced capitalist societies in the Asian-Pacific area but also the world's most populous country. If welfare state regimes can only coexist with western political democracies, then China and Hong Kong are excluded automatically. A similar result occurs if the traditional social administration approach is adopted whereby a "welfare state" is defined in terms only of direct state provision. The authors argue that such assumptions are untenable if state welfare is to be analyzed as a universal phenomenon. Instead of being trapped within an ethnocentric welfare statism, what social policy requires is a global political economy perspective that facilitates comparisons of the meaning of welfare and the state's role in producing it north, south, east and west.

China↗
PubMed1996

Report on consensus conference on colorectal cancer: Royal College of Surgeons of Edinburgh 1993.

Colorectal cancer is the second commonest cause of death from cancer in Scotland. Recent developments in molecular biology, pre-symptomatic diagnosis, surgery and adjuvant treatment suggest that a substantial reduction in mortality is achievable. Some fear that major changes to the organisation of the NHS could undermine future attempts to coordinate major cancer screening studies or multicentre adjuvant trials. In contrast, others argue that a sharp focus on cost and benefits could encourage the development of clear guidelines based on a consensus of good practice. Thus, the time seems right for a consensus conference and this article summarises the outcome of such a recent conference held in Scotland. A group of 80 surgeons, radiation oncologists and medical oncologists were invited as a representative cross-section of clinicians with an interest in colorectal cancer. Seventy per cent of those attending were surgeons. A series of expert presentations were used to lead discussion in four sessions devoted respectively to epidemiology and screening, influence of surgical factors and outcome, the role of adjuvant therapy and planning for the future. Full discussion from delegates was encouraged and computer-collated, key-pad responses allowed documentation of the opinions of the audience in respect of pre-defined questions. For statistical purposes we have assumed that a consensus had been reached when there was a statistically significant difference (Chi-square) between the observed response from clinicians and the null hypothesis, i.e. a 50/50 split.

Aftercare↗
PubMed1995

Increased incidence of levodopa therapy following metoclopramide use.

OBJECTIVE: To determine whether there is an increase in use of antiparkinsonian therapy in older persons taking metoclopramide hydrochloride. DESIGN: Case-control study. SETTING: New jersey Medicaid program. PATIENTS: Medicaid enrollees aged 65 years and older. Cases were patients newly prescribed a levodopa-containing medication (n = 1253); a secondary case group were patients newly prescribed an anticholinergic antiparkinsonian drug (n = 2377). The control group consisted of 16435 Medicaid enrollees older than 65 years who were not users of any antiparkinsonian therapy. MAIN OUTCOME MEASURES: We used logistic regression to determine the odds ratio (OR) for the initiation of antiparkinsonian therapy in patients using metoclopramide relative to nonusers, after adjusting for age, sex, race, nursing home residence, exposure to antipsychotic medication, and days hospitalized. RESULTS: Metoclopramide users were three times more likely to begin use of a levodopa-containing medication compared with nonusers (OR = 3.09; 95% confidence interval [Cl], 2.25 to 4.26). Risk increased with increasing daily metoclopramide dose: the OR was 1.19 (95% Cl, 0.50 to 2.81) for more than 0 to 10 mg per day, 3.33 (95% Cl, 1.98 to 5.58) for more than 10 to 20 mg per day, and 5.25 (95% Cl, 1.16 to 8.50) for more than 20mg per day. The effect persisted after adjustment for demographic, health service utilization, and medication use variables. The OR for initiation of anticholinergic antiparkinsonian drugs was also elevated in metoclopramide users. CONCLUSION: Metoclopramide use confers an increased risk for the initiation of treatment generally reserved for the management of idiopathic Parkinson's disease in patients with drug-induced parkinsonian symptoms, which should be ruled out before starting dopaminergic therapy for this condition.

Aged↗
PubMed1995

New four-million-year-old hominid species from Kanapoi and Allia Bay, Kenya.

Nine hominid dental, cranial and postcranial specimens from Kanapoi, Kenya, and 12 specimens from Allia Bay, Kenya, are described here as a new species of Australopithecus dating from between about 3.9 million and 4.2 million years ago. The mosaic of primitive and derived features shows this species to be a possible ancestor to Australopithecus afarensis and suggests that Ardipithecus ramidus is a sister species to this and all later hominids. A tibia establishes that hominids were bipedal at least half a million years before the previous earliest evidence showed.

Animals↗
PubMed1995

The role of the carboxy terminus of v-Rel in transformation and activation of endogenous gene expression.

Proteins within the Rel/NF-kappa B transcription factor family can be divided into two functional domains, a homologous amino terminal region, the Rel Homology Domain, and a divergent carboxy terminal domain. The amino terminal sequences specify DNA binding, nuclear localization, and interaction with the I kappa B family of inhibitory proteins. The carboxy terminus of each protein functions as a transcriptional activation domain, however, precise definition of sequence requirements has been difficult. To further define these sequences, small 100 bp deletions were constructed throughout the carboxy terminus of v-Rel. Each resulting mutant was assayed for DNA binding, localization, protein complex formation, activation of endogenous gene expression and ability to transform bone marrow cells and fibroblasts. Surprisingly, deletion within the carboxy terminus had marginal effects on transforming potential. However, three separate regions were required for full activation of gene expression. Taken together, these results suggest that the carboxy terminus of v-Rel contains multiple sequences that participate in the activation of gene expression.

Animals↗
PubMed1995

Postcranial estimates of body weight in Proconsul, with a note on a distal tibia of P. major from Napak, Uganda.

A distal tibia of Proconsul major from Napak, Uganda, is described. It is morphologically similar to other Proconsul tibiae, only much larger in size. This specimen and others are used to estimate the body weight of P. major from postcrania for the first time. Body weight is predicted from articular and diaphyseal dimensions using regression equations derived from a modern comparative sample of catarrhine primates. The estimated body weight of P. major based on the Napak tibia is 86.7 kg, whereas two other P. major specimens are smaller, giving a total range of 63.4-86.7 kg and an average of 75.1 kg. The regression equations are also used to predict the body weight of specimens from Rusinga/Mfangano belonging to P. nyanzae and P. heseloni. As the body weight estimates generated here are consistent with previous postcranial-based estimates for Proconsul species, the two sets of estimates are pooled to give means of 10.9 kg for P. heseloni (n = 6) and 35.6 kg for P. nyanzae (n = 12). These findings support the traditional assignment of two species at Rusinga/Mfangano. The postcranial body weight estimates for the three species of Proconsul are compared to body weights estimated from M1 area in order to investigate possible differences in scaling between the teeth and limbs in these species. Despite being based on a smaller sample size, the postcranial estimates clearly differentiate the three taxa, whereas the dental estimates form a more continuous distribution. Molar area overestimates body weight in P. heseloni, indicating that it is megadont compared to a large sample of modern anthropoid primates. In contrast, molar area underestimates body weight in P. Nyanzae and especially P. major, suggesting relative microdonty in these taxa.

Animals↗
PubMed1995

Managing the medical workforce: time for improvements?

There has been a regular cycle of Government committees in Britain that have forecast 'shortages' and 'surpluses' in medical manpower. It is remarkable how little change there has been in the methods used in these forecasts despite criticism of their methods and the move towards competitive markets in the delivery of health care. The practice of medical manpower planning was criticised in the 1960s because of the failure to explore the implications of alternative skill mixes and incentives. Whilst these criticisms were ignored, the forecasters now pay more regard to budget constraints and produce more regular estimates. The 1992 forecast could be improved by sensitivity analysis (e.g. for GP/population ratios). However, unless the issue of scope (forecasting for all health care staff, not just for doctors alone) and the implications of skill mix and incentives identified in the 1960s are addressed effectively, the current recommendations may produce doctor 'surpluses' in the early twenty-first century. The Government's analysis should be challenged at the level of principle and practice, and this implies that the research activity proposed in the 1960s is carried out in the 1990s to facilitate efficiency in the twenty-first century. Furthermore, the issue of policy priorities and their ranking needs to be spelt out explicitly: does the Government want a competitive NHS internal market, and if it does, what is the role of central manpower planning? One implication of current policy choice and the maintenance of manpower planning is that cost containment is of more importance to policy makers than the internal market.

Forecasting↗
PubMed1995

Programme budgeting and marginal analysis: application within programmes to assist purchasing in Greater Glasgow Health Board.

Recent NHS policy statements advocate the use of 'knowledge-based' purchasing. This paper describes an attempt to use an economic method to inform the purchasing process. The approach of programme budgeting and marginal analysis (PBMA) offers information on current service provision and provides a framework in which changes in a service can be evaluated and agreed within the context of a fixed budget. This has been applied to gynaecology services in Greater Glasgow Health Board and, following positive reaction to the results of this exercise, is now being extended into other areas. The process of carrying out the exercise is described. Additionally, limitations of the approach and the advantages of using PBMA in achieving knowledge-based purchasing are discussed.

Budgets↗
PubMed1995

Theory and methodology in premenstrual syndrome research.

Premenstrual Syndrome (PMS) is a controversial and ill-defined phenomenon, the aetiology of which remains an enigma, despite considerable research effort. In this paper, four meta-theoretical approaches to PMS are described and evaluated. Approaches to PMS can be criticised on three inter-related grounds. They have failed to describe women's experiences in detail before explaining them; they have not placed experience within its socio-cultural context; and they have assumed a linear relationship between biology or culture and behaviour. Future research can address these issues in two ways. Biopsychosocial models of PMS may integrate a variety of approaches and improve our understanding of individual experiences but are unlikely to offer new insights into the phenomenon of PMS. These are more likely to emerge from anthropological and sociological studies which question the cultural and individual meaning of PMS.

Arousal↗
PubMed1995

Neuroleptic drug exposure and treatment of parkinsonism in the elderly: a case-control study.

PURPOSE: Despite the widespread use of neuroleptic medications for the elderly, little is known about the frequency of treatment for drug-induced parkinsonian syndromes in this age group, particularly with L-dopa-type drugs, which are more appropriate for the treatment of true idiopathic Parkinson's disease. PATIENTS AND METHODS: We identified 3,512 patients aged 65 to 99 enrolled in a large state Medicaid program who were newly prescribed a drug to treat parkinsonian symptoms. Controls were comparable program enrollees of similar age who had not been prescribed an antiparkinsonian drug. In a case-control study, we evaluated the use of neuroleptic drugs in the 90 days before initiation of antiparkinsonian therapy. RESULTS: Patients taking neuroleptics were 5.4 times more likely to begin antiparkinsonian medication than were nonusers (95% confidence interval [CI] 4.8 to 6.1). They also had a greater than two-fold increase in risk of beginning therapy with a dopaminergic drug specific for idiopathic Parkinson's disease, not generally indicated for treatment of drug-induced parkinsonism (adjusted odds ratio 2.2, 95% CI 1.9 to 2.7). Clear dose-response relationships were demonstrated, as were differences among neuroleptics. Among all patients started on dopaminergic drugs in this population, 37% of such therapy was attributable to prior neuroleptic use. Continuation of the neuroleptic persisted in 71% of patients so treated. CONCLUSION: Neuroleptic use is a common cause of extrapyramidal dysfunction in the elderly, and the side effect is frequently treated by adding an anticholinergic or dopaminergic drug to the regimen. The use of anticholinergic drugs presents risks of additional drug side effects; the use of dopaminergic drugs, generally not appropriate for drug-induced parkinsonian syndrome, suggests that extrapyramidal neuroleptic side effects may often be mistaken for idiopathic Parkinson's disease in older patients.

Age Distribution↗
PubMed1995

Cigarette smoking and free radical activity in young adults with insulin-dependent diabetes.

Cigarette smoke is potentially capable of generating a high free radical load in the body and many patients with diabetes are smokers. This study was designed to investigate the relationship between long-term smoking and free radical activity in young adult insulin-dependent diabetic patients with no evidence of macrovascular disease. Eight-five patients (48 male) aged 17-40 years were studied. Mean duration of diabetes was 10.5 years (0.08-33) and 39 were cigarette smokers. All had normal serum creatinine levels. The free radical markers measured were: thiobarbituric acid reactive substances, glutathione peroxidase, and superoxide dismutase. No significant differences in thiobarbituric acid reactive substances, glutathione peroxidase, or superoxide dismutase, were found between the diabetic smokers and non-smokers. Also no difference was found comparing the diabetic patients with 40 non-diabetic control subjects (20 smokers). Persistent albuminuria was present in 16 patients (10 microalbuminuria) and free radical marker concentrations in these subjects were similar to the normoalbuminuric patients. This data suggests that any increase in free radical activity due to cigarette smoke is adequately scavenged in young adults with diabetes who are free of significant macrovascular disease.

Adolescent↗
PubMed1995

Determinants of fetal haemoglobin in newborn infants.

Percentage fetal haemoglobins (% HbF) were measured in 7081 newborns at the University Hospital, Nottingham, between 1990 and 1992 to assess the effects of a range of factors, and to determine if there was an association between % HbF at birth and risk of SIDS (sudden infant death syndrome). Data from the obstetric clinical records were analysed by multiple linear regression to establish the major determinants of % HbF. New findings were the identification of maternal smoking, twin pregnancy, ethnic origin, and season of birth as significant determinants. Alcohol use, drug and vitamin intake, and duration of labour were not found to be important. The previously reported correlations between % HbF and sex, gestational age, and birthweight were confirmed, and the relative effects quantified. Overall, the major determinants of an increase in % HbF in neonates are similar to the known antenatal risk factors for sudden infant death syndrome (SIDS).

Birth Weight↗
PubMed1995

A critique of 'at risk' pressure sore assessment tools.

This paper critiques pressure sore risk assessment tools. No attempt is made to describe individual tools in detail as this literature is available elsewhere. The economic case for risk assessment is presented along with the criteria for an effective risk assessment instrument. Reliability and validity studies are reviewed in relation to three risk assessment tools: Norton, Waterlow and Braden. Finally a number of issues related to threshold scores, research design and the need to view pressure sores as a clinical problem rather than a nursing problem are discussed.

Humans↗
PubMed1995

Communication standards: impact on nursing practice.

1. BACKGROUND INFORMATION. In order to meet the demands of processing large amounts of data, hospitals must look to innovative methods of information handling. One new method currently in use is the computerized patient record (CPR) (Dick & Steen, 1991). To successfully implement the CPR, many factors must be considered, including: (a) the fact that the database is dependent upon several different departments and resources for information; (b) the information needs of each department differs, making selection of a single information system that encompasses all users' needs difficult; and (c) operating systems may be incompatible, hampering the process of networking and exchanging, processing, and retrieving data in an integrated manner. Yet the integration of systems is central to the successful development of the CPR. 2. PURPOSE. Establishment of communication standards for health care promotes the effective integration of patient information across various computer systems (McDonald, 1990). To achieve this level of automation, standard organizations must unite in the development and implementation of communication standards for health care. This poster will explore: (a) data on communication standards; (b) the process of reaching standards; (c) established communication standards; and (d) the impact of communication standards on nursing practice. In addition, we will present a model for an integrated patient focused system of the future. Today, communication standards continue to evolve in health care. Many professional organizations share the goal of developing communication standards between clinical systems (McDonald, 1990). Standards to be explored in this poster include: the American Society for Testing and Materials (ASTM), the Medical Data Interchange Standard (MEDIX), the Medical Information Bus (MIB), and Health Level (HL7). Evolving standards will define protocols and procedures for the effective exchange of easy integration of information systems. Once standards are established for health care, society will benefit from the ability to: (a) compare health care costs; (b) measure the effectiveness of treatment; and (c) provide clinicians with comprehensive patient information (Rishel, 1992). 3. IMPLICATIONS. There is very little in existing literature and research studies on the impact of communication standards on nursing practice. Nurse researchers willing to assume the challenge of conducting studies on the impact of communication standards on nursing practice will forge new territory. Implications for nursing from the development of communication standards include: (a) increased productivity, (b) definition of a clinical data set, (c) improved quality patient care, and (d) easier system implementations.

Humans↗