Brenda J. Morrison

The effect of cigarette smoke from the mother on bronchial responsiveness and severity of symptoms in children with asthma

The effect of parental smoking was assessed in 94 consecutively observed children, aged 7 to 17 years, who had a history of asthmatic wheezing. The 24 children whose mothers smoked, when they were compared with children whose mothers did not smoke, had 47% more symptoms, a 13% lower mean FEV1 percent, a 23% lower mean FEF25-75%, and fourfold greater responsiveness to aerosolized histamine. A dose response was evident. There was a highly significant correlation between the results of the tests and the number of cigarettes the mother smoked while she was in the house. The differences between the children of smoking and nonsmoking mothers were greater in older than in younger subjects. The smoking habits of the father were not correlated with the severity of the childs asthma.

Airway responsiveness to histamine as a test for overall severity of asthma in children

Seventy-eight children who had a history of asthma were studied while they were symptom-free. There was a highly significant correlation between the dose of aerosolized histamine that produced a decrease in FEV1 of 20% and each of the features in the history that indicated severity of asthma. The correlation was strengthened by the combination of these features into a weighted asthma history score. None of the subjects with mildly increased bronchial reactivity had a history score of severe asthma, and none with markedly increased bronchial reactivity had mild asthma. There was also a highly significant correlation between histamine dose and the results of spirometric tests for airway obstruction. However, the correlation between asthma history score and provocative histamine dose was highly significant even in the 21 subjects who were apparently free of airway obstruction at the time of testing. Furthermore, the correlation between asthma history score and histamine dose was stronger than that between asthma score and any spirometric test, indicating that the histamine test more accurately assessed the overall severity of the asthma. Measurement of bronchial responsiveness to histamine is a useful adjunct to history in determining the severity of asthma in an individual and should be considered as an objective way of grading subjects according to severity of asthma in a clinical study.

The decrease in severity of asthma in children of parents who smoke since the parents have been exposing them to less cigarette smoke

BACKGROUND In 1985 we became aware that the smoking of parents aggravates their childrens asthma. Since then we have advised all referring doctors to urge parents not to expose their asthmatic children to smoke. METHODS We investigated 807 nonsmoking asthmatic children, from 1 through 17 years of age, who were consecutively referred between 1983 and 1990. We compared the children who were seen before July 1986 with those seen after that date. RESULTS Those seen in the later period had intimate exposure to a far smaller number of cigarettes smoked per day, both by mothers (7 vs 3, p = 0.005) and by fathers (5 2, p = 0.001). A concurrent improvement was observed in adjusted measures of asthma severity in their children (asthma score 7.5 vs 6.5, p = 0.047; forced expiratory volume in 1 second as a percent of predicted [FEV1%] 79.2 vs 93.7, p = 0.000; and forced expiratory flow rate during middle half of forced vital capacity [FEF25%-75%] 67.3 vs 82.0, p = 0.009), and for every cigarette less smoked in the room with the child the FEV1 increased by 3%. When parents of those seen in the later period were asked whether they had been told that smoke would aggravate their childs asthma, 80% affirmed that they had. The difference in asthma severity between the two time periods was much less in children of nonsmokers than in children of smokers. CONCLUSION It appears that if parents are aware that smoke will aggravate their childs asthma, the child will be exposed to fewer cigarettes, and the asthma will be less severe.

Definition and Application of a Histopathological Scoring Scheme for an Animal Model of Acute Mycoplasma pneumoniae Pulmonary Infection

A histopathological scoring system was developed to assess the pathology of acute Mycoplasma pneumoniae pulmonary infection in a hamster model. A final score per animal (ranging 0–26) is obtained by averaging scores from each lung which have been accumulated by the addition of subscores from the assessments of quantity and quality of peribronchiolar and peribronchial infiltrates, luminal exudates, perivascular infiltrates, and parenchymal pneumonia. The scoring scheme was then applied to test the ability of a heat‐killed inoculum to induce pulmonary pathology and to the trial of a 43 kDa protein‐associated antigen as a vaccine immunogen. A heat‐killed inoculum delivered by both intratracheal and intranasal routes did not induce pulmonary pathology compared to a live inoculum (respective mean scores 0.1, 6.7; P<0.01). Animals prevaccinated with the 43 kDa antigen developed an accentuated pathological response after live challenge compared to those unvaccinated (respective mean scores 16.8, 5.8; P=0.00007). Hypersensitization to growth medium components may, however, have contributed to the accentuated disease since the lungs of vaccinated animals challenged with culture‐negative media also were affected (mean score 5.4). Reproducibility of the scoring system was measured by duplicate reading of histology slides which were randomized to the observer upon the second reading (r=0.93; P=0.000009). The scoring system has the ability to differentiate disease severity in small groups of animals.

The frequency and severity of cat allergy vs. dog allergy in atopic children

Questions were put to parents accompanying 1238 children, 1 to 17 yr old, who had symptoms of respiratory tract allergy. Skin prick tests were then performed. Symptoms after exposure to cats and positive skin test results from cat hair extract were significantly more frequent than symptoms after exposure to dogs or reactions to dog hair extract. The prevalence of symptoms and positive skin test reactions to cat allergens increased with age, significantly more so than the reaction or symptoms after exposure to dog allergens. The greater frequency of sensitivity to cats was not caused by exposure to cats in more homes, since dogs significantly outnumbered cats as the household pet in both atopic and nonatopic families. However, greater intimacy of exposure to cats when they were present may have been a factor because cats, significantly more often than dogs, were inside the house and in the childs bedroom. Two subgroups were examined to determine whether those with cat sensitivity who owned cats had more severe symptoms than those with dog sensitivity who owned dogs. Numbers were small and differences not statistically significant, but those in the cat subgroup more frequently had persistent allergic nasal symptoms and abnormally low spirometric measurements than did those in the dog subgroup. Our findings indicate that children are more often allergic to cats than to dogs and suggest that the greater frequency of sensitization to cats may be due to increased intimacy of exposure to cats.

It is children with atopic dermatitis who develop asthma more frequently if the mother smokes

We elicited symptoms of atopic dermatitis (AD) and of asthma from 620 children who were themselves nonsmokers, were aged 1 to 17 years, and had been consecutively referred to an allergy clinic. A histamine bronchial-challenge test revealed bronchial hyperresponsiveness in 95% of the children who had a history of wheezing or asthma and who could perform the test reliably, indicating that most of them did indeed have asthma. Children with a history of AD were much more likely to have asthma if the mother was a smoker than if she was a nonsmoker (79% versus 52%; p = 0.001). Similarly, if AD was found on examination, the percentages with asthma were 74% and 44%, respectively. By contrast, the children with no history of AD had asthma as frequently if the mother was a nonsmoker (42%) as when she was a smoker (40%). In children with AD, the prevalence of asthma was greater in both boys and girls when the mother was a smoker, but only in boys when the father was a smoker. Multiple logistic regression confirmed that the risk of asthma was greatly increased when the child had both AD and a mother who smoked.

Diagnosis of house dust mite allergy in asthmatic children: what constitutes a positive history?

Standardized questions were put to the parents of 530 children, referred consecutively for evaluation of asthma, to determine which features in the history were associated with house-dust mite allergy. Bronchial challenge tests performed on 19 of the children confirmed that there is a highly significant association between a positive skin prick test and a positive bronchial challenge test to Dermatophagoides farinae mite antigen. One hundred and eighteen (23%) of the children had positive prick tests to the mite. There is a highly significant association between a positive prick test to mite and a history that the subjects respiratory symptoms become worse when there is exposure to domestic activity that stirs up house dust (vacuuming, dusting, sweeping, making the bed, or shaking out blankets) or that the symptoms improve when out of doors. Seasonal variation and other features in the history are of little value in distinguishing mite-sensitive from mite-insensitive asthmatics. Although the 4% whose only positive prick test reaction was to mite had significant worsening of asthma during the colder months compared with the remainder, most mite-positive subjects had multiple allergies and had no characteristic seasonal pattern. The presence of a positive prick test to mite was not associated with aggravation of asthma either at night in bed or in the morning on awakening. A history similar to that of mite-sensitive subjects was elicited in those with a positive prick test to house dust. A positive history of house dust or house-dust mite allergy in asthmatics is one in which respiratory symptoms become worse during domestic activity that stirs up house dust or improve when outdoors.

Potential exposure of cooks to airborne mutagens and carcinogens

Recent case-control and proportionate mortality studies in Canada, the United States, Britain, and Denmark have shown that cooks and other food-service workers may have elevated risks of cancers of the nasopharynx, buccal cavity, esophagus, lung, and bladder. The purpose of this pilot study was to determine if there might be airborne products of cooking which may be risk factors for these cancers in cooks. Eight air samples were taken in four restaurants and subsequently analyzed for mutagenicity using the Ames assay, and for carcinogens using gas chromatography/mass spectrometry. All four samples taken in the restaurant cooking areas were mutagenic to TA98 without metabolic activation, and two were mutagenic to TA100 also without metabolic activation. Of the four dining area samples, one was mutagenic to TA100 and one to TA98, both without metabolic activation. Compounds tentatively identified by mass spectrometry did not include known carcinogens. The ventilation systems in all four restaurants allow the exposure of cooks to both the air from dining room smoking areas and the volatile products of cooking.

Level and Distribution of Employee Exposures to Total and Respirable Wood Dust in Two Canadian Sawmills

Personal respirable (N = 230) and total (N = 237) dust measurements were made in two coastal British Columbia sawmills using a sampling strategy that randomly selected workers from all jobs in the mills over two seasons. Information about job title, department, season, weather conditions, location of the job relative to wood-cutting machines, and control measures also was collected at the time of sampling. Only 16 respirable wood dust samples were above the detection limit of 0.08 mg/m3; all 16 had levels < or = 0.20 mg/m3. Total wood dust concentrations were also low (36% less than the detection limit), with a mean of 0.51 mg/m3, and ranging from < 0.08 to 52 mg/m3. Measurements of exposure taken close to chippers, planers, and multiple saws had the highest total wood dust levels. Sawmill department and booth enclosures also were associated with wood dust concentrations, while local exhaust ventilation and weather conditions were not. Wood dust levels in this study were generally lower than in other studies of this industry, but most sawmill investigations report mean wood dust concentrations lower than those measured in the furniture and cabinetmaking industries, where concerns about wood dust exposures initially were raised.

The effect of triphasic and biphasic oral contraceptive preparations on HDL-cholesterol and LDL-cholesterol in young women

Lipid changes were measured during two consecutive studies on efficacy, side effects, and metabolic changes of oral contraceptive (OC) preparations. The mean lipid values of women on OCs at the start of the two studies were compared to those of women who had not taken OCs for at least 3 months. It was found that LDL-cholesterol (LDL-C) mean values of the women on OCs were higher than the mean values of women who had not taken OCs for at least 3 months. In study #1, women received the OC preparation Triphasil. In study #2, women were randomised to one of 3 OC preparations (Triphasil, Ortho 777 or Ortho 10/11). HDL-cholesterol (HDL-C) and LDL-C were measured over time at six months and at 12 months after receiving the study medications. The results show that HDL-C increased in women on Ortho 777 and 10/11 and decreased in women on Triphasil at six months, and these changes were not found at 12 months. The results showed change over time for the LDL-C mean values, in that women not on OCs at the start of the studies had increased LDL-C mean values, and women on OCs at the start of the studies had decreased LDL-C mean values. Further the LDL-C mean values in women not on OCs at the start of the studies who received Triphasil (containing the gonane progestin dl-norgestrel) increased over time, whereas the combined mean values of those who received Ortho 777 and Ortho 10/11 (containing the estrane progestin norethindrone) did not increase over time.(ABSTRACT TRUNCATED AT 250 WORDS)