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Biomedical subjects

J B Howell

Publications and source records attributed to J B Howell.

At least 19 recordsLinked to original sources
PubMed1991

Respiratory symptoms among elderly people in the New Forest area as assessed by postal questionnaire.

This study was carried out to estimate the prevalence of respiratory symptoms among people aged 65 years and older and assess the value of a postal survey in obtaining this information. A questionnaire was sent to 2011 subjects (957 men) drawn by age-stratified random sampling from the age-sex registers of four New Forest group practices (1:3.3 sample). A total of 1803 replied, a 96.2% response after excluding 136 who had died or moved from the area. The accuracy of replies was verified for 355 (20%) randomly selected subjects. Forty per cent had no respiratory symptoms. Exertional breathlessness was common (38%), increasing in prevalence with age but not with smoking history, and was the only symptom reported by 10% of subjects. Only 14.2% were current smokers; more of the subjects aged 85 years and over were lifelong non-smokers. Two hundred and ninety-six (16.4%) had chronic bronchitis, which was more common among smokers; 151 (8.4%) gave a history of asthma, of whom half (76) had active asthma, which was slightly less common among the very elderly subjects. Only 489 (27.1%) of subjects had seen their doctors with chest symptoms during the preceding 2 years.

Age Factors↗
PubMed1989

Cutaneous defects of focal dermal hypoplasia: an ectomesodermal dysplasia syndrome.

The 5 major cutaneous defects of development found in focal dermal hypoplasia, an ectomesodermal dysplasia syndrome, are: aplasia cutis congenita, multiform atrophy-like areas, striate, papillomatous, and lipomatous lesions of skin. Subepidermal lipomatosis, present in some lesions, has been reported to be due to absence of dermis or a striking underdevelopment of connective tissue with replacement by adipose tissue from herniation of subcutaneous fat through multiple areas of hypoplasia. We believe this theory to be a major error in interpretation of the microscopic findings. We have had the unique experience of studying 2 patients periodically for 27-30 years and 2 additional patients for a shorter time. Biopsy specimens were removed at intervals for analysis from the same or similar lesions (43 specimens) from these 4 individuals. Our evidence strongly supports the concept that the cutaneous defects of development involving fat cells represent heterotopic fat i.e. a fat nevus resulting from dysplasia, not hypoplasia followed by herniation of subcutaneous fat.

Adipose Tissue↗
PubMed1989

Prevalence of respiratory symptoms among 7 and 11 year old schoolchildren and association with asthma.

A new self administered questionnaire completed by parents was used to study the prevalences of wheeze, shortness of breath, and cough in 2503 Southampton schoolchildren aged 7 and 11 together with exacerbating factors and background information including treatment and diagnosis. The questionnaire had a response rate of 84% and was found to be highly repeatable with respect to current symptoms. The overall prevalences of wheeze and shortness of breath in the current year (1986) were 12.1% and 8.5% respectively. Social class, home ownership, parental smoking, and presence of a family pet were unrelated to symptom prevalence. According to the parents the overall diagnosis rate for asthma was 9.5%. In common with other studies, however, we found considerable evidence for undertreatment. The symptoms of wheeze and nocturnal and morning breathlessness occurred more commonly in boys, but this sex ratio decreased with increasing age. The prevalences of wheeze and shortness of breath were similar in the two age groups. In contrast, there were only small differences between the sexes with respect to cough whereas, among children without wheeze or shortness of breath, there was a fall in the prevalence of cough from 18.9% at 7 years to 8.7% at 11 years. When controlling for the other respiratory symptoms, wheeze was the only symptom significantly related to parental asthma. The fall in the prevalence of cough between the two age groups is unlikely to be related to changes in asthma prevalence and, when not associated with wheeze, may be an indicator of separate pathology.

Age Factors↗
PubMed1989

Prevalence of atopy and range of bronchial response to methacholine in 7 and 11 year old schoolchildren.

A sample of 397 from 2503 children aged 7 and 11 years, who took part in an earlier questionnaire study of respiratory symptoms in Southampton, was chosen for methacholine bronchial provocation and allergen skin testing. Results were obtained from 330 (84%). A good level of repeatability was achieved for bronchial provocation testing giving a 95% confidence interval equivalent to 1.74 doubling concentrations. The main problem encountered with methacholine was its bitter taste in high concentrations. The proportion of children, in whom the dose of methacholine which produced a fall of 20% in the forced expiratory volume in one second (PD20 methacholine) was less than or equal to 6.4 mumol, fell from 29.1% at 7 years to 16.5% at 11 years. The prevalence of atopy increased from 26% at 7 years to 31.6% at 11 years. A highly significant association was found between bronchial responsiveness to methacholine and atopy, which was independent of symptoms or age group.

Bronchi↗
PubMed1989

Associations between respiratory symptoms, bronchial response to methacholine, and atopy in two age groups of schoolchildren.

Data on respiratory symptoms were obtained on 2503 schoolchildren aged 7 and 11 in Southampton by means of a self administered parental questionnaire. Children were classified into seven symptom groups from which 330 were tested for bronchial responsiveness to less than or equal to 6.4 mumol methacholine and skin tested for the presence of atopy. The symptoms of wheeze, cough, and shortness of breath were all significantly associated both with each other and bronchial responsiveness to methacholine but only wheeze was associated with atopy. The association of wheeze with both bronchial responsiveness to methacholine and atopy remained highly significant when controlling for the symptoms of cough and shortness of breath. Neither cough nor shortness of breath, however, were significantly related to bronchial responsiveness to methacholine when controlling for the symptom of wheeze. This study therefore calls into question the epidemiological relevance of these two symptoms as diagnostic features of asthma, particularly in the absence of wheeze, although they may be useful indicators of morbidity. Wheeze was not related to bronchial responsiveness to methacholine in the absence of atopy or to atopy in the absence of bronchial responsiveness to methacholine but was strongly related to the combination of the two phenomena. The presence of these three characteristics could therefore indicate a discrete disease entity. The decrease in the prevalence of cough between 7 and 11 years appeared to be mirrored by a similar decrease in the prevalence of wheeze when the symptom was not associated with the combination of bronchial responsiveness to methacholine and atopy. On the basis of these findings and those of others we suggest that the latter group may represent children with a separate disease entity(ies) or with residual symptoms secondary to acute viral or other infections of the lower respiratory tract.

Asthma↗
PubMed1979

The effect of increased ventilation on resistive load discrimination.

The ability of normal subjects to detect the addition of external resistive loads was determined both at rest and when ventilation was increased to more than 30 L/min by CO2 administration or exercise. Tidal volume, flow, and mouth and transpulmonary pressures were recorded during resistive load discrimination using standard psychophysical techniques. The mean resistance detection threshold was 0.40 +/- 0.06 cm H2O/L/s at rest, 0.36 cm H2O/L/s during administration of CO2, and 0.44 cm H2O/L/s with exercise. The Weber fraction was 0.28 +/- 0.04 at rest, 0.29 +/- 0.08 with CO2, and 0.34 +/- 0.04 with exercise. The lack of change in the ability to detect resistive loads when ventilation was increased was surprising because changes in both pressure and flow were tripled. The findings were supportive of the hypothesis that resistance or something like it is perceived, rather than change in flow or pressure.

Adult↗
PubMed1978

Reticular pigmented anomaly of the flexures.

Reticular pigmented anomaly of the flexures (Dowling-Degos' anomaly) is a rare, benign, new genodermatosis that has recently evolved from independent observations and studies by several dermatologists. Because of its favorable prognosis, differentiation of this benign disorder from acanthosis nigricans, a cutaneous marker of possible or existing internal malignant disease, is highly important. Careful clinical appraisal of the eruption in correlation with the characteristic microscopic features makes the diagnosis simple and straightforward.

Humans↗
PubMed1976

Assessment of responsiveness to carbon dioxide in patients with chronic airways obstruction by rate of isometric inspiratory pressure development.

1. Responsiveness to CO2 was measured in forty patients with chronic airways obstruction in terms of ventilation and rate of isometric inspiratory pressure change [(dP/dt)max]. 2. The ventilatory response was below the normal range in eighteen out of twenty-two patients with normal arterial CO2 tensions and in all of eighteen patients with CO2 retention. 2. The (dP/dt)max. response was distributed throughout the normal range in all but one of the patients with normal arterial CO2 tension. In all the patients with CO2 retention the (dP/dt)max. response was either at or below the lower limit of the normal range. 4. Although the ventilatory responses correlated significantly with FEV1 there was no such correlation for the (dP/dt)max. responses. 5. The (dP/dt)max. response showed a significant negative correlation with Pa,CO2. 6. It is believed that the (dP/dt)max. response to CO2 can be used to assess central CO2 responsiveness in subjects with airways obstruction independently of mechanical factors limiting their ventilation.

Aged↗