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Biomedical subjects

N Wilson

Publications and source records attributed to N Wilson.

At least 37 records · Page 2Linked to original sources
PubMed1995

Delivery of hepatitis B immunisations in a selection of computerised general practices.

AIM: To assess the value of computerised general practices in providing information concerning the delivery of hepatitis B immunisation. METHODS: Hepatitis B immunisation data from August 1990 to June 1991 were collected from 27 general practices participating in a sentinel network. RESULTS: The study identified significant limitations in the use of data from computerised general practices for estimating hepatitis B immunisation coverage. While an accurate coverage figure could not be estimated, the results did suggest that hepatitis B coverage for three doses was at least 59.5% and that its use was very similar to the triple vaccine and measles/MMR for the third dose. Hepatitis B immunisation delivery outside the desirable time periods was common at 44%, suggesting a fairly disrupted immunisation schedule for many children. CONCLUSIONS: The relatively infrequent delivery of hepatitis B vaccine at the same time as other vaccinations may reflect provider concern about administering multiple injections at the same visit. Further improvement in the collection of data by computerised practices is necessary before the full value of this data source can be realised. Improvements in reminder/recall systems would improve the efficiency with which hepatitis B immunisation is delivered.

Child, Preschool↗
PubMed1995

Hearing impairment in older adults: new concepts.

OBJECTIVE: To review present information about the epidemiology, etiologies, pathogenesis, evaluation, and quality of life aspects of hearing loss and to present an approach to rehabilitation for hearing loss in older adults. DESIGN: A survey of recent findings on the problem of hearing loss in older adults, efficacy of intervention with amplification, and new developments in intervention strategies. CONCLUSIONS: The complex nature of hearing problems in older adults involves changes in the auditory periphery as well as in the central mechanisms for processing sound input. These changes affect the social and emotional impact of the hearing disorder. The importance of understanding the many implications of hearing loss on quality of life is emphasized. Both older adults and immediate family members need information and advice about the consequences of age-related hearing loss. The physician has a key role in helping them to overcome negative attitudes toward a hearing handicap. For most older persons, hearing aids alleviate many of the handicaps of hearing impairment. For some older persons who do not benefit adequately from conventional hearing aids, assistive listening devices may be helpful. Many old persons and their relatives are reluctant to confront the reality of hearing handicap and try to hide the fact that they need sound amplification. One important future direction is to foster acceptance of hearing loss and to support the more open use of amplification systems.

Aged↗
PubMed1995

Effect of continuous treatment with topical corticosteroid on episodic viral wheeze in preschool children.

Acute episodic wheeze related to viral infections is a common and distressing condition and treatment remains unsatisfactory. Although some benefit from the continuous use of inhaled steroids has been demonstrated in young wheezy children, their effect primarily on acute episodes has not been considered. In this study the effect of budesonide (400 micrograms/day) was assessed in a four month double blind parallel trial, in 41 children (0.7-6.0 years) with predominantly episodic viral wheeze. Analysis of the last three months showed no difference between budesonide or placebo in mean daily total symptom score (median values 0.6 and 0.63), episode number (mean values 2.6 and 2.4), or score/episode (mean value 30 and 31). Four months of treatment with inhaled budesonide had no effect on acute episodes of wheeze in this group of children.

Acute Disease↗
PubMed1995

Reducing donor exposure in preterm infants requiring multiple blood transfusions.

Preterm infants frequently require multiple blood transfusions. Traditionally, 'fresh' (less than seven days old) blood has been used but this often results in transfusions from multiple donors. To reduce donor exposure the policy for top-up transfusions was changed. A unit of blood under five days old with additional satellite packs was ordered for each infant and used up to its expiry date, allowing up to eight transfusions from a single donation to be given. The mean (SD) number of transfusions per infant in 43 infants transfused according to previous policy and in 29 transfused according to the new policy was similar at 5.6 (4.0) and 5.3 (3.1), respectively. However, donor exposure fell following the change in policy from 4.9 (3.5) to only 2.0 (0.9). Only one infant was exposed to more than three donors compared with 24 infants in the control group. Plasma potassium concentrations were not significantly different following transfusion of blood stored for up to 33 days. This simple change in policy has reduced donor exposure in infants requiring multiple top-up transfusions.

Blood Donors↗
PubMed1995

Closure of Blalock-Taussig shunts using a new detachable coil device.

Two children underwent interventional closure of a modified Blalock-Taussig shunt using a new detachable coil system (Duct-Occlud). This procedure has advantages over currently available materials to occlude these and other communications between the systemic and pulmonary circulations.

Arteriovenous Shunt, Surgical↗
PubMed1994

Comparison of interferon-gamma and interleukin-4 production by peripheral blood mononuclear cells and isolated T cells after activation with polyclonal T cell activators.

Controversial data have been reported regarding the ability of peripheral blood T cells to secrete interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) from atopic patients as compared to nonatopic healthy controls. In most of these studies, T cells in peripheral blood mononuclear cell preparations (PBMC) were stimulated with polyclonal T cell activators. Some of these activators are able to activate cells other than T cells in the PBMC preparations which may influence the lymphokine levels in supernatants of PBMC. To evaluate this, we compared the IFN-gamma and IL-4 levels in PBMC and isolated T cell preparations after activation with phytohemagglutinin (PHA), Concanavalin A (ConA), anti-CD3 plus phorbol myristate acetate (PMA), or ionomycin plus PMA. The IFN-gamma and IL-4 levels in the supernatants were calculated based on the percent T cells in the preparations. Whereas all activators induced significant IFN-gamma secretion, only ionomycin plus PMA stimulation induced large IL-4 secretion. In virtually all cases, the IFN-gamma levels calculated on a per T cell basis differed for PBMC versus isolated T cells. Whereas in some donors the IFN-gamma levels were higher in PBMC preparations than in T cells, in others it was the opposite. Similarly, in about one half of both normal and atopic donors tested, the IL-4 levels of activated PBMC were 2- to 7-fold lower than levels in isolated T cells. The data suggest that non-T cells have a significant effect on the IFN-gamma and IL-4 levels in supernatants of polyclonally activated PBMC.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1994

Transesophageal echocardiography in children with cardiac assist.

Transesophageal echocardiography (TEE) is an easy, relatively non-invasive method for evaluation of cardiac function and abnormalities during cardiac assist. We used 19 TEE in 9 children (age: 10 days-4 years, weight: 2.7-12 kg) with mechanically assisted circulation for postcardiotomy cardiogenic shock. TEE provided valuable information: (1) dislocation of the cannula causing hemodynamic instability could be easily diagnosed and corrected; (2) Doppler evaluation of valvular function revealed severe malfunction in two patients; (3) intracardiac thrombus could be clearly detected in two children with seriously impaired hemodynamics. These findings were followed by therapeutic interventions; (4) left-ventricular function before attempted weaning from cardiac assist was moderately reduced or normal in the survivors, but poor in the nonsurvivors. We conclude that TEE is a valuable contribution to improved patient management during cardiac assist.

Child, Preschool↗
PubMed1994

The Audiant Bone Conductor: update of patient results in North America.

The Xomed Audiant Bone Conductor is an implantable hearing device for conductive hearing impairments not adequately relieved by surgical methods or hearing aid amplification. It has now been used long enough for analysis of its present position in our management armamentarium. Data obtained from respondents from the United States and Canada are presented and indicate that this device, properly prescribed and used, almost eliminates the conductive elements of the hearing impairment. During the early years of its use, the device was frequently implanted in patients outside the manufacturer's guidelines for use. Some of the reasons for this discrepancy, as well as evidence that this misapplication is lessening, are presented. When proper guidelines were used, however, the results presented here indicate that socially adequate hearing can be restored to patients with conductive loss by the Audiant. Complications have been few and appear to be diminishing. The results indicate that this device has, in its present state of development, a narrow and restrictive application, but a well-defined and efficient role to play in the management of conductive hearing impairment.

Adolescent↗
PubMed1993

Ultrasound detection of fetal structural abnormalities in Auckland 1988-9.

AIMS: To conduct an audit of ultrasound screening for fetal abnormalities in central Auckland 1988-89. METHOD: All babies born at National Women's Hospital in the time period were examined and fetal abnormalities coded on to a computer database. All terminations of pregnancy for fetal abnormality in the area were similarly audited. RESULTS: There were 12,909 births. 218 babies had a congenital abnormality of whom 88% were scanned antenatally. 48% of abnormalities were detected (27% before 24 weeks). In fetuses that were scanned the detection rate was 52% (44% before 24 weeks). The range of detection of specific abnormalities included neural tube defects 95% and congenital heart defects 16%. CONCLUSIONS: 1. Major abnormalities of the central nervous system, renal tract and abdominal wall have a high detection rate. 2. Cardiovascular, facial and gastrointestinal abnormalities are either not detectable or difficult to detect. 3. Detection rates could be improved by routine scanning, better ultrasound equipment and training, and by the introduction of maternal biochemical screening tests. 4. The detection rate is similar to other overseas surveys.

Abortion, Therapeutic↗
PubMed1993

Obesity and body fat distribution in New Zealanders: a pattern of coronary heart disease risk.

AIMS: To describe the prevalence of obesity and the body fat distribution of New Zealanders. To discuss this in the context of the coronary heart disease risk. METHODS: Body weight and height, body mass index (BMI), waist:hip ratio (WHR) and six skinfold measurements were determined for 3204 randomly selected New Zealanders who responded to an invitation to a health check (response rate 56%). RESULTS: In the study sample BMI generally increased with age. Fifty five percent of men and 38 per cent of women aged 18-64 had a BMI exceeding 25, and of these 13 per cent and 10 per cent were obese (BMI > 30). WHR was greater in men than in women of all ages, and a third of the men and a quarter of the women had values exceeding 0.9 and 0.8 respectively. Central skinfold measurements (subscapular, suprailiac and abdominal) were lowest in young men, but rose markedly with age and were similar to women above age 35. Limb skinfolds were lower in men. CONCLUSIONS: This survey indicates that a large percentage of New Zealanders are overweight or obese and their excess body fat tends to be centrally distributed, especially in men. Obesity is thus a significant health problem in New Zealand.

Adipose Tissue↗
PubMed1993

Effect of foot compression on the velocity and volume of blood flow in the deep veins.

The A-V Impulse System reduces the incidence of deep vein thrombosis by pneumatically compressing the venae comitantes of the lateral plantar artery, causing an increase in the velocity of blood in the proximal axial veins. Using a duplex scanner the effects of altering the pressure, pulse duration and frequency of foot compression on the velocity and volume of blood flow in the superficial femoral and popliteal veins were quantified. In 20 legs, foot compression of 50, 125 and 200 mmHg significantly increased the maximum venous blood flow by 9.0, 13.4 and 15.1 ml/s respectively (P < 0.001). Conversely, reducing the frequency of compression from 6 to 3 cycles per min significantly increased the rise in peak flow from 10.1 to 14.8 ml/s (P < 0.001). Changing the duration of compression from 1 to 3 s had no significant effect on peak flow. Increased blood flow is best achieved with high-pressure low-frequency foot compression. Increasing the duration of compression beyond 1 s has no effect on augmentation of flow in the deep veins.

Adult↗
PubMed1993

Prolonged isoproterenol treatment alters immunoregulatory cell traffic and function in the rat.

The mechanisms by which the sympathetic nervous system modulates functional parameters of the immune system have not been fully defined. In vivo, acute and chronic beta 2-adrenergic stimulation have been shown to have dramatic but opposing effects on circulating lymphocyte number and subset distribution in humans. In vitro studies have suggested impairment of numerous lymphocyte effector functions in the presence of catecholamines. To better define the effects of short and long term beta-adrenergic stimulation on lymphocyte migration patterns between circulating and splenic pools, as well as function, we infused rats with either low or high doses of isoproterenol over various time intervals. Specifically, we determined the number and subset composition of peripheral blood and splenic lymphocytes in addition to assessing responsivity to the T cell mitogen concanavalin A and antibody production. As a measure of in vivo lymphocyte proliferation, we also monitored the effect of these infusions on the number of peripheral blood lymphocytes and splenocytes and the splenic weight. Isoproterenol led to dose-dependent, short-lived decrements in mitogen-induced lymphocyte proliferation with concomitant decreases in circulating and splenic lymphocyte number in a subset-specific manner. Analysis of the distribution of circulating and splenic subtypes with isoproterenol treatment suggests definite but limited influences on beta-adrenergic stimulation on immunoregulatory cell traffic. We conclude that beta-adrenergic stimulation in the rat model leads to a dose-dependent, transient effect on lymphocyte proliferation and migration patterns. The relative lack of functional beta-receptors on rat lymphocytes and the propensity for early sustained receptor desensitization on exposure to agonist may account for qualitative differences seen between rats and humans.

Animals↗
PubMed1993

Relationship of the antihypertensive effect of vasopressin withdrawal to sodium excretion in the Doca-salt hypertensive rat.

Arterial pressure, sodium excretion, urine output, and plasma atrial natriuretic peptide (ANP) concentrations were measured before, during, and after a 3-h i.v. infusion of arginine-vasopressin (vasopressin; 20 ng/kg/min) in conscious Doca-salt hypertensive rats. Arterial pressure was 166 +/- 8 mm Hg before the infusion of vasopressin; in comparison, pressure was only 130 +/- 4 mm Hg 5 h after stopping the infusion. The fall in pressure after withdrawal of an equipressor dose of phenylephrine in hypertensive animals was much less. In sham normotensive rats, pressure did not fall below control levels after stopping either the vasopressin or phenylephrine infusion. Sodium excretion rates were higher during infusions of vasopressin than during phenylephrine infusions. However, the elevations observed during vasopressin were similar in the hypertensive (25.3 +/- 4.9 mumol/kg/min) and normotensive (22.9 +/- 2.7 mumol/kg/min) groups. Urinary output increased to a greater extent in the hypertensive rats during the infusions of both vasopressin and phenylephrine, but the increases were similar for the 2 pressor agents. Plasma levels of ANP were elevated during the infusions of vasopressin in the normotensive rats, but not in hypertensive rats. The results indicate that the fall in pressure associated with cessation of a pressor dose of vasopressin appears specific to the hypertensive state, and relatively specific to vasopressin. This withdrawal-induced antihypertensive phenomenon (WAP) does not appear to be due solely to the preceding natriuresis and diuresis during the infusion of vasopressin. However, because the hypertensive animal may be more sensitive to a given degree of sodium loss, the possibility that the natriuresis could play a contributing or permissive role cannot be excluded.

Animals↗
PubMed1993

Exemplar.

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Dyspnea↗
PubMed1993

[Transcatheter obliteration of patent ductus arteriosus in young adults with the Rashkind occluder].

Fourteen young adult patients between 14 and 29 years of age underwent 15 procedures of transcatheter occlusion of patent ductus arteriosus. In all patients but one, the attempt to implant the device was successful (92%). In one patient the ductus was judged to be too large for occlusion and the patient was sent for surgery. In no patient did the device embolize. A total of 6/13 (46%) patients was discharged home with no residual shunt. Follow-up data (between 3 and 18 months) are available in 10/13 patients. To date, 9/13 (70%) had total occlusion of their duct, in one patient after reocclusion.

Adolescent↗