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J Ward

Publications and source records attributed to J Ward.

At least 253 records · Page 14Linked to original sources
PubMed1991

Prevention of invasive Haemophilus influenzae type b disease: lessons from vaccine efficacy trials.

To assess vaccines, multiple laboratory investigations and immunogenicity studies are conducted but the ultimate tests of the effectiveness of a vaccine are field trials that evaluate disease prevention. Immunogenicity studies are often used as a surrogate for protection, but it is often difficult to determine precisely the level of antibody needed for protection and it is not always clear what immunologic factors most determine protection. However, efficacy trials are difficult to conduct well and there are only a limited number of ways to perform such studies. Nonetheless, the results of efficacy studies are essential for the appropriate selection of the best Hib vaccines and to establish recommendations for optimal use. The first Hib vaccine, the PRP (polyribosylribitol phosphate) polysaccharide vaccine, was shown by several efficacy studies to have no protective efficacy in young infants, and to have only limited, if any, efficacy in older children. The first Hib polysaccharide conjugate vaccine, PRP-D, is more immunogenic and provides better protection than PRP in older children (greater than 18 months of age), but it has limitations in both immunogenicity and protective efficacy when given to children younger than 6 months of age. Newer, more promising, Hib conjugate vaccines are now available, and include HbOC, PRP-OMP, and PRP-T vaccines. Each is currently being evaluated in field trials to evaluate protective efficacy and the methods and results of these trials will be reviewed. The control of invasive Hib disease worldwide will depend upon the appropriate application of knowledge derived from these field trials.

Bacterial Vaccines↗
PubMed1991

The reliability and validity of a scale to measure HIV risk-taking behaviour among intravenous drug users.

The initiation and maintenance of substantial behaviour change is required to reduce the spread of HIV infection among the intravenous drug-using population. In order to ascertain the efficacy of interventions aimed at reducing HIV-related risk-taking behaviour among this population, valid and reliable (yet preferably short) instruments for measuring such behaviour are required. The HIV risk-taking behaviour scale (HRBS) is a brief 11-item interviewer-administered scale which examines the behaviour of intravenous drug users in relation to both injecting and sexual behaviour. This paper describes the construction of the scale, in addition to data evaluating its reliability and validity. Initial analyses indicate that the scale has satisfactory psychometric properties.

Adolescent↗
PubMed1991

Estimating drug consumption in opioid users: reliability and validity of a 'recent use' episodes method.

The efficient and accurate measurement of recent drug use is an essential component of treatment and research among opioid users. Urinalysis results alone will not give sufficient information to either the clinician or researcher, due to limitations in detection and an inability to distinguish extent of use. The present paper describes a 'recent use episodes method', adapted from the measurement of alcohol consumption, for obtaining self-reported drug use in eleven different drug categories. Reliability and validity data indicate that the method provides a quick means by which accurate information may be obtained on the overall recent drug use of opioid users.

Adult↗
PubMed1991

A scale for estimating the health status of opioid users.

The health status of injecting drug users has both clinical and research relevance. In order to evaluate the impact of treatments for opiate dependence on drug users' health status we need valid and reliable instruments which are short and easily administered by non-medical personnel. This paper describes the construction of a brief interviewer administered scale for assessing the current health status of injecting drug users. Data evaluating its reliability and validity are presented which indicate that the scale has excellent psychometric properties.

Adolescent↗
PubMed1991

Measurement of breathlessness during exercise in asthmatics. Predictor variables, reliability, and responsiveness.

The purpose of this study was to determine the predictor variables for breathlessness and to investigate the criteria of reliability and responsiveness for measuring breathlessness during progressive, incremental exercise on the cycle ergometer. We studied a heterogeneous group of patients with stable asthma (mean +/- SEM age, 46 +/- 4 yr) for four visits at weekly intervals. Predictor variables were determined at the first visit. Nine independent physiologic variables were obtained at each minute during exercise; the Borg rating of breathlessness (range 0 to 10) was used as the dependent variable. The regression model relating the physiologic parameters to the Borg rating of breathlessness was highly significant (model F = 43.4; p = 0.0001). Backward elimination selected the strongest predictors of the Borg rating: peak inspiratory flow (VI); tidal volume (VT)/FVC; frequency of respiration (f); and peak inspiratory mouth pressures (Pm). These four variables explained 63% of the variance in the rating of dyspnea. Each of the four variables exhibited a linear relationship with the Borg rating. Test-retest reliability was assessed by comparing results at the first and second visits. Individual slopes (except for VT/FVC) and intercepts for the four predictor variables versus Borg ratings were highly reliable. The slope for work intensity (watts) and Borg ratings, but not the intercept, was highly reliable. Responsiveness was evaluated by randomly administering inhaled methacholine or inhaled metaproterenol, alternately, at the third and fourth visits to induce acute changes in lung function before exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Cytodifferentiation of mouse mammary epithelial cells cultured on a reconstituted basement membrane reveals striking similarities to development in vivo.

In the present study we provide evidence that the cytodifferentiation of primary mouse mammary epithelial cells within the alveolar-like structures formed after culture on a reconstituted basement membrane resembles development in vivo during late pregnancy and early lactation. During the first two days in culture on a basement membrane gel in the presence of lactogenic hormones, epithelial cells isolated from mid-pregnant mice are disorganized and central lumina are largely absent. Levels of mRNA for the milk proteins, beta-casein and transferrin, are dramatically reduced. By the second or third day in culture, cytoplasmic polarization becomes evident and prominent apical junctional complexes are formed. Synthesis of both mRNA and milk protein is reinitiated at this time. By day 4, well-defined lumina appear, and abundant synthesis and secretion of casein and lipid is observed. A striking feature of this differentiation in culture is the specific localization of milk protein gene expression (beta-casein mRNA) to luminal epithelial cells in the alveolar-like structures. At the ultrastructural level, increased milk protein synthesis and secretion are paralleled by a fourfold increase in rough ER that resembles the dramatic increase in the ER observed in vivo following parturition. One indication of tissue-specific differentiation observed in later cultures (days 4-11) is the synthesis and secretion of abundant casein micelles. A second characteristic of lactating mammary epithelial cells in vivo that has not previously been observed in culture is the secretion of milk fat globules. Taken together, these observations indicate that mammary epithelial cells plated onto a reconstituted basement membrane differentiate to the lactating phenotype in culture.

Animals↗
PubMed1991

Cancer prevention: what's worth doing in general practice?

Primary prevention aims to circumvent the onset of malignant change. Secondary prevention aims to detect early cancer or lesions with high malignant potential before extensive local growth or metastatic spread compromises the effectiveness of treatment. This article should help general practitioners appraise the value of cancer prevention measures and plan an effective approach to cancer prevention in clinical practice.

Family Practice↗
PubMed1991

Locomotor-respiratory coupling develops in novice female rowers with training.

The purpose of this study was to investigate the hypothesis that locomotor-respiratory coupling (LRC), or entrainment of breathing, develops in the sport of rowing as a result of training. We prospectively evaluated exercise responses over an 8 month training session (October to May) in 12 female subjects who were members of the Dartmouth College novice rowing team. Progressive, incremental exercise testing was performed on the variable-resistance rowing ergometer (Concept II, Morrisville, VT). To relate the pattern of breathing to the mechanics of rowing, the catch and finish of each rowing stroke during the last 30 s of each minute of exercise were marked on the strip chart paper that recorded inspiratory flow measured by using a heated pneumotachograph. Age was 18 +/- 1 yr (mean +/- SE); weight was 67.5 +/- 2.1 kg. Peak oxygen consumption (VO2) increased by 10% from October (40.8 +/- 0.6 ml.kg.min-1) to May (P less than 0.001). Chi-square goodness-of-fit analysis was used to assess whether the proportion of inspirations occurring in each of four quadrants of circle plots representing repetitive rowing strokes exercise intensities of 100 watts (W) and peak VO2 were random or corresponded to a regular pattern of breathing. Although 5 of 12 subjects demonstrated LRC at exercise of 100 W in October, there was no significant change at this submaximal intensity over the training season. Only 2 of 12 subjects showed LRC at peak exercise in October, but there was a significant increase (P = 0.003) in the number of subjects who entrained breathing in Jan (10/12) and May (8/12).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Type I lissencephaly syndrome. Clinical, neuroradiologic and electrographic analysis].

A case with lissencephaly (agyria) syndrome is described. This brain development defect must be included in the differential diagnosis of all infants with delayed motor development and congenital malformations and convulsions, especially of the infantile spasms kind. It is important to consider chromosomal studies in each of them and to offer genetic counseling to the parents.

Cerebral Cortex↗
PubMed1991

Infantile myofibromatosis of the temporal bone: a case report.

We present the first case of solitary temporal bone infantile myofibromatosis. This benign entity clinically and radiologically resembles a malignant process. Diagnosis is established with biopsy and electron microscopy studies. Local resection is the recommended treatment.

Fibroma↗
PubMed1991

Neuropsychological functioning in human immunodeficiency virus type 1 seropositive children infected through neonatal blood transfusion.

The neuropsychological development of 15 human immunodeficiency virus type 1 (HIV-1) seropositive children infected through neonatal blood transfusion was compared with that of a control group of 33 HIV-1 seronegative children who had also received blood transfusions as neonates. Human immunodeficiency virus type 1 infection was identified on the basis of a callback blood testing. Two thirds of the HIV-1-infected children were asymptomatic at time of enrollment in the study of development. The children were administered two psychological batteries approximately 8 months apart. The results indicated that the two serostatus groups did not differ in overall intelligence, even as long as 8 years after HIV-1 infection. Significant group differences, though slight, were found on school achievement and on tasks that require motor speed, visual scanning, and cognitive flexibility. Continued longitudinal study of this cohort will be important in characterizing the evolution of neuropsychological deficits.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Turning audit around.

Explore the source record for details and available documents.

Administrative Personnel↗
PubMed1990

Limited efficacy of a Haemophilus influenzae type b conjugate vaccine in Alaska Native infants. The Alaska H. influenzae Vaccine Study Group.

BACKGROUND: The prevention of invasive Haemophilus influenzae type b disease requires a vaccine that is effective when administered during the first six months of life. The infants of Alaska Natives are at particularly high risk of invasive H. influenzae type b disease. METHODS: To evaluate the protective efficacy of a H. influenzae type b polysaccharide-diphtheria toxoid conjugate vaccine (polyribosylribitol phosphate-diphtheria toxoid [PRP-D]), we enrolled 2102 Alaska Native infants in a randomized, double-blind, placebo-controlled trial in which either the vaccine or a saline placebo was administered at approximately two, four, and six months of age. RESULTS: After 3969 subject-years of follow-up and 32 episodes of H. influenzae type b disease, the overall incidence of invasive disease was not reduced significantly in the vaccinated subjects (6.0 cases per 1000 patient-years), as compared with the placebo controls (9.6) or with other Alaska Native infants (6.0). After one, two, or three doses there was no significant protective efficacy with the vaccine; after three doses the efficacy was only 35 percent (95 percent confidence interval, -57 to 73). The lack of efficacy was not related to the age at onset of disease, age at immunization, type of disease, degree of Alaska Native heritage, time after immunization, or year of the study. Levels of H. influenzae type b anticapsular antibody in recipients of the vaccine became significantly higher than levels in those who received placebo only after the second and third doses. Even after the third dose, only 48 percent of the vaccinated infants had antibody levels of more than 0.1 microgram per milliliter (geometric mean titer, 0.18). Antibody responses did not vary with the level of maternally acquired antibody, degree of Alaska Native ancestry, or age at time of the first or second immunizations, but they increased with increasing age at time of the third dose (P less than 0.001). CONCLUSIONS: We found no evidence that the PRP-D vaccine provides significant protection, at least for Alaska Native infants, against invasive diseases caused by H. influenzae type b. The ineffectiveness of the vaccine paralleled its limited immunogenicity.

Age Factors↗
PubMed1990

Interpractice visits by general practitioners: implications of a pilot project for quality assurance in general practice.

This article describes a pilot study involving 25 general practitioners who agreed to undertake interpractice visits. Decisions regarding the nature, length and documentation of the interpractice visit were made by consensus during a 5-h workshop. Participants met again as a group after the visits were completed and discussed the acceptability of the visits and their potential to improve standards of care. Reactions included a high level of enthusiasm to develop further the rigour of these visits.

Australia↗
PubMed1990

In vivo measurement of brain water by MRI.

A new method for determining brain tissue water using MRI, developed in the laboratory, has been tested and applied to the clinical setting. To evaluate the accuracy of the technique, samples of human brain tissue were harvested from patients scheduled to undergo surgical removal of tumour and in whom biopsies were required for clinical management. MR determined values from imaging water maps compared favourably with gravimetric measures of samples. From these data, we conclude that accurate non-invasive measures of brain oedema in man are now possible.

Biopsy↗
PubMed1990

Epididymal metastasis from prostatic adenocarcinoma mimicking adenomatoid tumor.

A case of epididymal metastasis from prostatic carcinoma is presented. The initial histologic findings were suggestive of adenomatoid tumor, but a diagnosis of metastatic adenocarcinoma of prostatic origin has been established by prostatic acid phosphatase and prostate-specific antigen immunoperoxidase staining.

Acid Phosphatase↗