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Biomedical subjects

H R Anderson

Publications and source records attributed to H R Anderson.

At least 127 records · Page 7Linked to original sources

An introduction to the practice, prevalence and chemical toxicology of volatile substance abuse.

1. Volatile substance abuse is largely a teenage practice; it is estimated that in the UK 3.5-10% of young people have at least experimented and that 0.5-1% are current users. 2. The products abused are many and varied but only about 20 chemical compounds, notably toluene, chlorinated solvents such as 1,1,1-trichloroethane, fuel gases such as butane and aerosol propellants, are commonly encountered. 3. The acute hazard varies with the compound, product and mode of abuse. Mortality in the UK is now about 100 per year, from all social classes, 90% of whom are male. 4. Chronic toxicity is difficult to assess, partly because of the diversity of products abused. However it is clear that some long-term abusers suffer permanent damage to the central nervous system, heart, liver and kidney. 5. Toxicological analysis may be relied upon for confirmation of diagnosis, providing attention is paid to the kinetics of excretion and stability in the sample. 6. Responses include codes of practice for the sale of products and educational strategies; legislation has also been enacted. There is little evidence that any of these measures have made a significant impact on the problem.

Adhesives↗

Neuropsychological consequences of volatile substance abuse: a review.

1. The evidence from studies of the neuropsychological consequences of chronic volatile substance abuse is reviewed. 2. Studies of occupational exposure to solvent vapour are of limited relevance when considering the effects of volatile substance abuse because occupational exposure is normally to small quantities of many different compounds over prolonged periods of time. 3. Many studies of chronic volatile substance abusers suffer from serious shortcomings such as the use of small sample sizes, inadequate controls, failure to exclude the possibility of acute toxic effects and a disregard of other factors which could account for the findings. 4. There is reasonably good evidence that neuropsychological impairment is often present amongst volatile substance abusers with definite neurological abnormalities. 5. Although most studies have found that volatile substance abusers without reported neurological abnormalities obtain lower psychometric test scores than non-abusers, it remains uncertain whether these deficits are best explained in terms of a causal effect of volatile substance abuse, rather than a reflection of other factors associated with volatile substance abuse, such as background, social disadvantages or history of delinquency.

Environmental Exposure↗

Randomized controlled trial of small group education on the outcome of chronic asthma in general practice.

The effectiveness of small group education of general practitioners in the management of asthma was evaluated by randomized controlled trial. The outcome measure was the asthma morbidity of the general practitioners' own patients. Following random selection from the list of one family practitioner committee in suburban London, the 27 participating general practitioners were allocated randomly to one of two educational groups or to a control group. The educational intervention comprised eight meetings at which the management of chronic asthma was discussed and attempts made to devise agreed strategies for care. The two educational groups devised different strategies. Asthma morbidity was assessed by postal questionnaires to patients before the intervention and on five further occasions at six-monthly intervals over two and a half years. Of 454 patients who entered the study 338 completed the sixth and final assessment. The degree of morbidity experienced by the patients and their reported use of asthma specific drugs was considerable and was notably constant over the period of study. There was no difference in morbidity between the three groups at the outset and no effect of the intervention could be demonstrated. In this educational intervention the participating general practitioners were not informed about the morbidity and drug use reported by their patients. This information may be crucial if small groups are to be used to design and implement effective strategies for care. It would appear that small group education of general practitioners in the form reported here is not effective in reducing morbidity from chronic asthma.

Adolescent↗

Asthma as a link between chest illness in childhood and chronic cough and phlegm in young adults.

The link between chest illnesses in childhood to age 7 and the prevalence of cough and phlegm in the winter reported at age 23 was investigated in a cohort of 10,557 British children born in one week in 1958 (national child development study). Both pneumonia and asthma or wheezy bronchitis to age 7 were associated with a significant excess in the prevalence of chronic cough and phlegm at age 23 after controlling for current smoking. This excess was largely attributable to the association of cough and phlegm at age 23 with a history of asthma or wheezy bronchitis from age 16. When adjustment was made for recent wheezing, current cigarette consumption, previous smoking habit, and passive exposure to smoke the relative odds of cough or phlegm, or both, in subjects with a history of childhood chest illness was 1.11 (95% confidence interval 0.97 to 1.27). When analysed separately asthma, wheezy bronchitis, and pneumonia up to age 7 did not significantly increase the prevalence of either cough or phlegm. The explanation for the observed continuity between chest illness in childhood and respiratory symptoms in later life may lie more in the time course of functional disturbances related to asthma than in the persistence of structural lung damage.

Asthma↗

Relationship between psychosocial factors and asthma morbidity.

A general practice study was designed to describe certain psychosocial attributes of asthma patients and to relate these to reported asthma morbidity in the previous two years. A postal questionnaire on their respiratory morbidity was completed in September 1983 and again in September 1985 by 207 asthma patients. They then completed a postal questionnaire concerning their attitudes to asthma and level of family support. The findings revealed a marked degree of psychosocial morbidity among patients. Family support showed no significant associations with past or current levels of morbidity, or with changes in morbidity over the previous two years. In contrast, negative attitudes to asthma were correlated with significantly higher levels of morbidity, the strongest associations being found between patients' present attitudes and their most recent level of morbidity. These findings in conjunction with work carried out elsewhere suggest that high levels of asthma morbidity bring about a negative attitude to the condition which in turn contributes towards continuing morbidity.

Adolescent↗

Prospective study of mortality associated with chronic lung disease and smoking in Papua New Guinea.

In Papua New Guinea a 15-year mortality follow-up was carried out among 2026 highlanders and 1734 coastal dwellers on whom data on respiratory symptoms and signs, and lung function had been obtained by prevalence surveys in 1970/71. Survival status was established in 99%, of whom 9.8% had died, the rate being higher in the highland (12.2%) than in the coastal population (7.0%). All abnormalities indicative of chronic lung disease were associated with increased mortality though this was statistically significant only for chronic shortness of breath (SMR 195) and wheezing (SMR 183) in coastal females. In those aged 25 years or more there was a strong association between reduced lung function (FEV1, FVC, FEV1/FVC%) and mortality, after controlling for age and height. The associations observed were as strong as those reported from prospective studies in developed countries. The most striking difference was that in Papua New Guinea mortality showed no association whatever with tobacco smoking; this may be because the traditional type of tobacco and method of smoking it resembles pipe/cigar smoking in developed countries.

Adolescent↗

The interaction between the deacetylated (amine) metabolite of diamphenethide (DAMD) and cytochemically demonstrable Na+/K+-ATPase activity in the tegument of Fasciola hepatica.

The relative effects on tegumental Na+/K+-ATPase activity in Fasciola hepatica of the deacetylated (amine) metabolite of diamphenethide (DAMD) (10 micrograms/ml, 18 h) and the Na+/K+-ATPase inhibitor ouabain (0.1 mM, 0.5 h) have been assessed cytochemically. In the normal tegument, Na+/K+-ATPase activity is particularly concentrated along the invaginations of the apical plasma membrane and the infoldings of the basal plasma membrane. Ouabain pretreatment significantly reduces the overall level of Na+/K+-ATPase activity, but does not induce swelling of the basal infolds. In contrast, DAMD does not significantly reduce either the level or distribution of Na+/K+-ATPase activity, but does cause a pronounced swelling of the basal infolds. The results are discussed in relation to the postulated action of diamphenethide as an inhibitor of Na+/K+-ATPase activity.

Acetanilides↗

Fasciola hepatica: tegumental surface alterations following treatment in vitro with the deacetylated (amine) metabolite of diamphenethide.

The effect of the deacetylated (amine) metabolite of diamphenethide (10 micrograms/ml) on the tegumental surface of Fasciola hepatica over a 24 h period in vitro has been determined by scanning electron microscopy. Blebbing begins around the oral sucker after 3 h and then passes backwards along the body, reaching the ventral sucker and midbody by 6 h, and finally the posterior end of the body (by 12 h). Initially, the blebs are small, the tegument surrounding the spines is swollen and the tegument generally has a smooth, swollen appearance. This submerges the spines below the body surface. At higher magnification the surface is seen to bear microvillous-like projections in addition to the blebs and surface pitting is deeper than normal. Later on, the blebs increase in size and burst, causing lesions and loss of spines. Lesions begin to appear on the oral cone and ventral sucker after 6 h, in the midbody by 12 h and on the dorsal surface of the posterior region after 24 h. By this time the damage is extensive: around the oral and ventral suckers, and over large areas of the oral cone and midbody region the tegument has been stripped off to expose the basal lamina beneath. The dorsal surface of the fluke is consistently more severely affected than the ventral surface.

Acetanilides↗

Ethnic variation in respiratory morbidity and lung function in childhood.

In a population of 5689 primary schoolchildren there were few important differences between children of European (n = 5287), African (n = 198), and Indian origin (n = 204) in the prevalence of a history of past respiratory illnesses or current respiratory symptoms. The reported 12 month period prevalence of the symptom "ever wheezy" was 15%, 18%, and 17% respectively in the three ethnic groups (differences not significant). In a subsample of 973 European, 47 African, and 40 Indian children forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were significantly lower by 12% and 13% in Africans and by 8% and 9% in Indians than in Europeans after adjustment to the group mean height of 128 cm. No significant ethnic variation was found for forced mid expiratory flow, FEV1/FVC, or mean transit time. Since the lung function studies were performed on a sample from a large population with little variation in respiratory morbidity, the differences are likely to reflect human biological differences. Separate prediction equations need to be developed for the different ethnic groups in childhood.

Adolescent↗

Risk factors for asthma up to 16 years of age. Evidence from a national cohort study.

From a national cohort of 8,806 children examined at ages seven, 11 and 16 years (National Child Development Study), data on asthma or wheezing illness (AW) were analyzed to describe its natural history in childhood and its risk factors. Factors found to predict the subsequent onset of asthma included male sex of child, mother's age at the child's birth, pneumonia, whooping cough, tonsillectomy/adenoidectomy, allergic rhinitis, eczema and periodic abdominal pain/vomiting attacks. A wide range of perinatal factors, including feeding practices, and social and family factors were shown to have no effect on natural history.

Adolescent↗

Controlled evaluation of the effects of patient education on asthma morbidity in general practice.

Two different patient education programmes for asthma in general practice were evaluated in a controlled trial. Knowledge, self management, and morbidity due to asthma were assessed in 339 patients by means of a questionnaire. One group then received a maximum education programme, a second group received a limited education programme, and a third acted as a control group. 274 patients were reassessed after one 1 year. In both the intervention groups, understanding of asthma was greater after the trial. Only in the maximum intervention group was a significant improvement in knowledge of asthma shown. Neither group showed any change in self-management ability or asthma morbidity that differed significantly from changes in the control group. These simple informational education programmes were ineffective when applied to a general practice population. Further studies of factors affecting attitudes, beliefs, and actions are needed to improve the advice and support given to asthma patients.

Activities of Daily Living↗