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Biomedical subjects

S Redman

Publications and source records attributed to S Redman.

105 records · Page 6Linked to original sources
PubMed1983

The time course of synaptic potentials evoked in cat spinal motoneurones at identified group Ia synapses.

Excitatory post-synaptic potentials (e.p.s.p.s) were evoked in motoneurones by impulses in single group Ia axons. After recording the e.p.s.p., the motoneurone and the group Ia axon were injected with horseradish peroxidase. The morphological details of the connexion formed by each group Ia axon with a motoneurone were subsequently reconstructed. Four Ia axon-motoneurone pairs were obtained. The electrotonic distance from the soma to each synaptic bouton in the connexion was calculated. The electrotonic lengths of those dendrites on which synaptic connexions were found were also calculated. The shape indices of each recorded e.p.s.p. and the standard cable model of the motoneurone were used to calculate the electrotonic distance from the soma to the point on the equivalent dendritic cable at which the e.p.s.p. originated. This distance was compared with the distance obtained from the reconstruction of the synaptic connexion at which the e.p.s.p. was generated. For two of the four connexions, the locations calculated by both methods agreed to within 0.1 lambda. Similar agreement could only be obtained for the other two connexions if synaptic transmission did not occur at some of the boutons in the termination. Evidence that some boutons were not involved in transmission is presented in the following paper (Redman & Walmsley, 1983).

Animals↗
PubMed1983

Amplitude fluctuations in synaptic potentials evoked in cat spinal motoneurones at identified group Ia synapses.

Excitatory post-synaptic potentials (e.p.s.p.s) were evoked in spinal motoneurones (of anaesthetized cats) by impulses in single group Ia axons. The morphological details of the Ia axon-motoneurone connexion involved in generating each e.p.s.p. were subsequently reconstructed, as described by Redman & Walmsley (1983). The fluctuation pattern of the peak amplitude of each e.p.s.p. was determined using a deconvolution method, taking into account the recording noise. Four e.p.s.p.s were analysed. One did not fluctuate in amplitude; the others fluctuated between discrete amplitudes which were separated by quantal increments. The number of increments which must be added to produce the largest peak amplitude of each e.p.s.p. was always less than, or equal to, the number of synaptic boutons in the connexion at which the e.p.s.p. was generated. The results are consistent with the hypothesis that transmission occurs in an all-or-none manner at each synaptic bouton. Different boutons in the termination of a Ia axon with a motoneurone have different probabilities of releasing transmitter, and this probability is sometimes zero at low stimulation rates. The results support the idea that the discrete amplitudes of an evoked e.p.s.p. result from intermittent transmission, in an all-or-none manner, at some or all of the boutons in the termination.

Animals↗
PubMed1980

The recovery of a random variable from a noisy record with application to the study of fluctuations in synaptic potentials.

Analysis of fluctuations in the amplitude of evoked synaptic potentials can be severely handicapped by the presence of spontaneous synaptic potentials and recording noise. A numerical procedure has been described whereby it is possible to remove some of the masking effects of this noise from the underlying distribution of the fluctuating synaptic potentials. it is not necessary to make an initial assumption about the type of distribution which will best describe the fluctuations. To use this technique, it is necessary to measure the histograms which approximate the probability densities of both the noise, and the noisy evoked potential. It is also necessary to assume that the statistical mechanisms generating the noise are independent of those mechanisms which cause the fluctuation in synaptic transmission, and that the noise and the evoked potentials add linearly. The statistical reliability of the technique depends upon the amount of noise present, and the sample size. Problems of resolution which arise from finite sampling and high noise levels are discussed.

Afferent Pathways↗
PubMedDate not supplied

Two sequential randomized trials of community participation to recruit women for mammographic screening.

BACKGROUND: If mammographic screening is to reduce mortality from breast cancer, it is essential that a high proportion of the target population attend for screening. In order to achieve this, effective recruitment strategies are needed. This paper reports two trials of recruitment strategies for mammographic screening involving eight communities in rural New South Wales (NSW), Australia. METHODS: Each trial involved two matched pairs of towns in the Hunter Valley region of NSW. Towns were randomly allocated to intervention, receiving either mass media promotion or community participation in Trial 1 and community participation or family physician involvement in Trial 2. RESULTS: In Trial 1, significantly higher attendance rates were observed in the two towns that received the community participation intervention compared with their matched media promotion towns (63% vs 34%, P < 0.001 and 51% vs 34%, P < 0.01). In Trial 2, a significantly higher attendance rate was observed in one town that received the family physician involvement intervention compared with its matched town which received the community participation intervention (68% vs 51%, P < 0.01). There was no significant difference in attendance in the other pair of towns (68% vs 58%, P = 0.11). CONCLUSIONS: Both community participation and family practitioner involvement are more promising strategies for the promotion of attendance at mammographic screening facilities than media promotion alone.

Adult↗
PubMedDate not supplied

Disordered eating and unhealthy weight reduction practices among adolescent females.

BACKGROUND: Dissatisfaction with body weight and the use of unhealthy weight reduction practices have been reported among adolescent females. There is a need for methodologically rigorous studies using large representative samples of adolescent females to accurately assess the prevalence of these behaviors and attitudes. METHODS: Eight hundred sixty-nine Australian school girls ages 14-16 years were administered a self-report questionnaire to determine the prevalence of disordered eating behaviors, unhealthy dieting practices, and distorted body image. Anthropometric (height and weight) data were collected on each of these adolescent females. RESULTS: The prevalences of disordered eating, unhealthy dieting, and distorted body image were 33, 57, and 12%, respectively. Over one-third (36%) of the total sample had used at least one "extreme" dieting method in the past month, i.e., "crash" dieting, fasting, slimming tablets, diuretics, laxatives, and/or cigarettes to lose weight. Of the total sample, 77% wanted to lose weight and 51% had tried to lose weight in the past month. Motivating factors for disordered eating and unhealthy dieting behaviors were peer pressure, media pressure, and the perception that extreme dieting strategies were harmless. CONCLUSION: The prevalence of disordered eating and dieting behaviors among adolescent females shown by this study suggests the need for preventive programs encouraging appropriate eating and dieting behaviors.

Adolescent↗
PubMedDate not supplied

The accuracy of self-report of smoking status in pregnant women.

Little is known about the accuracy of usual-care providers' detection of pregnant smokers. This study explored the proportion of pregnant women misclassified as nonsmokers by midwives in a public antenatal clinic. A sample of 204 women whom midwives classified as nonsmokers were asked to complete a self-administered questionnaire and to provide a urine specimen for cotinine analysis. Results indicate that midwives failed to detect a significant proportion of smokers. The conservative estimate of the proportion of midwife-identified nonsmokers who could be reclassified as smokers on the basis of the questionnaire and urinalysis procedures was 7.4% (95% CI 3.8-10.9%), the medium estimate was 8.8% (95% CI 4.9-12.7%) and the worst-case estimate was 15.2% (95% CI 10.3-20.1%). To increase the coverage achieved by smoking-cessation programs, antenatal clinics should consider incorporating biochemical measurements into routine screening procedures. Future studies examining smoking status in pregnancy should detail the methods used to classify subjects and document response rates in relation to each self-report and biochemical measurement.

Confidence Intervals↗
PubMedDate not supplied

The hippocampus, long-term potentiation and memory.

1. The induction of long-term potentiation (LTP) at excitatory synapses on CA1 pyramidal neurons occurs partly through an increase in the quantal AMPA current. It is also accompanied by an increase in the number of active sites. Any presynaptic modification, requiring the presence of a retrograde messenger, remains uncertain. 2. There are no definitive data that establish a causal link between LTP and the formation of memories. Pharmacological blockage of NMDA and mGLU receptors and genetic mutants with proteins deleted that are thought to be involved in LTP induction or maintenance or in the formation of memories have all linked deficits in LTP with impairments to behavioural learning, but these links are not necessarily causal. The development of tissue- and time-specific lesion of gene expression for multiple gene products may overcome the present limitations of gene deletion experiments and provide more revealing insights into the relationship between LTP and memory.

Animals↗
PubMedDate not supplied

Patient-provider interactions and patient outcomes.

Research shows that a number of provider interactional skills are empirically related to patient adherence, making interaction skills a necessary and important part of clinical competence. These skills fall into three broad categories: techniques to elicit and modify patients' health and treatment beliefs, to aid recall of information, and to aid adherence. Specific skills in each category are discussed. Research further shows that health care providers can be taught effective communication skills, and that one of the most effective teaching techniques is audio or video feedback in which the provider's interaction with a patient is judged by tutor and peers using explicit, empirically based criteria.

Attitude to Health↗
PubMedDate not supplied

The relative effectiveness of educational and behavioral instruction programs for patients with NIDDM: a randomized trial.

In this randomized trial patients with non-insulin-dependent diabetes were allocated to one of four programs: a minimal instruction program (n = 59), and education program of individual visits (n = 57), an education program incorporating a group education course (n = 66), and a behavioral program (n = 59). Individual and group education programs had higher attrition rates than the behavioral and minimal programs. The four programs, which involved different amounts of patient contact time, delivery format, and instructional strategies, all produced reductions in HbA1 and BMI, with no significant differences between the programs. There were no differences between groups over three time periods in total cholesterol, HDL cholesterol, systolic blood pressure, or proportion of patients consulting an ophthalmologist. The behavioral program produced a greater reduction in diastolic blood pressure over 12 months than the education programs and a greater reduction in the cholesterol risk ratio over 3 months than the other programs. The behavioral program patients were more likely to have visited a podiatrist after 6 months and reported higher satisfaction.

Adolescent↗
PubMedDate not supplied

Increasing women's compliance with opportunistic cervical cancer screening: a randomized trial.

Our objective was to evaluate the efficacy and acceptability of two interventions designed to increase opportunistic cervical cancer screening. We designed a randomized trial of two interventions additional to usual care. We recruited 17 male general practitioners selected at random from the inner metropolitan region of Sydney, Australia. The patients were 202 women, between 20 and 65 years of age, eligible for a Pap smear. We allocated minimal and maximal interactional interventions to obtain consent for a Pap smear. Our main outcome measure was women's having a Pap smear during the consultation or within one month. We also measured acceptability of interventions to practitioners and women. These were our results: minimal: 55% of women had a Pap smear; maximal: 67% of women had a Pap smear; total when both approaches are combined: 61%. We conclude that brief advice is as effective as maximal persuasion in increasing women's compliance with opportunistic screening in routine consultations. Both interventions were acceptable to women. Practitioners preferred the minimal intervention. We demonstrate opportunistic screening is an effective and acceptable way to encourage women at risk to have a Pap smear.

Adult↗
PubMedDate not supplied

Self-reported cognitive change during pregnancy.

Two groups of women were studied to elicit their perceptions of cognitive changes during pregnancy. In the first phase of the study, 236 primiparous women were surveyed using a structured questionnaire three to five days after delivering their baby. Sixty-four percent of women reported changes in cognition during pregnancy. More changes were reported by the women who were older, better educated, married or living as married, had private health insurance and had attended an obstetrician during pregnancy. Phase 2 was designed to survey and assess the content (type, range and salience) of the cognitive changes. Forty-eight multigravid and primigravid women and two postpartum women were surveyed using a semi-structured questionnaire; 82% reported experiencing cognitive changes during pregnancy and postpartum, including difficulty in concentration, absentmindedness and short-term memory loss. It is argued that while prior research has associated altered mental functioning during pregnancy with psychiatric disturbance, this is not a necessary relationship. Education about cognitive changes during pregnancy may assist women to understand a common experience and to develop effective coping strategies.

Adaptation, Psychological↗
PubMedDate not supplied

Community action for health promotion: a review of methods and outcomes 1990-1995.

OBJECTIVE: Our objective was to explore the effectiveness of community action as a strategy for health promotion, through a critical review of five years of community action evaluation literature. METHODS: Community action was defined as a health promotion, program that involved the community in implementation and control of the process of the program. Criteria for scientific evaluation of programs were proposed for sampling and control procedures, reliability and validity of instruments, analysis techniques, and specification of details of the intervention. A critical review of the literature, located by an on-line and related reference search, was undertaken for community action aimed at reducing cancer and cardiovascular disease, between January 1990 and May 1995. RESULTS: None of seven community action studies (17 articles) that examined cancer risk factors fulfilled all the criteria for rigorous scientific evaluation. The most methodologically adequate cancer study, the COMMIT intervention, had only a moderate degree of success in reducing community smoking rates. Similarly, none of the six studies (25 articles) on cardiovascular disease fulfilled all the criteria. The results for the most methodologically adequate study, the Minnesota Heart Health Program, were disappointing, with strong secular trends preventing adequate assessment of the intervention effect. CONCLUSIONS: The finding that none of the reviewed studies met all evaluation criteria was due to several factors, including political considerations, feasibility, and the continued evolution of the science of evaluation in health promotion. Some important questions are posed for researchers by the failure of methodologically superior projects, such as COMMIT, to show major gains in reducing health risk behaviors.

Cardiovascular Diseases↗