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Biomedical subjects

B J Morrison

Publications and source records attributed to B J Morrison.

At least 37 records · Page 2Linked to original sources
PubMed1990

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.

Adolescent↗
PubMed1990

Using noise exposure histories to quantify duration of vibration exposure in tree fallers.

A study of tree fallers in the British Columbia forest industry was done to determine if noise histories could be used to monitor the daily duration of exposure to hand-arm vibration from chain saws. Field observations and noise dosimetry showed that chain saw noise was distinguishable from other sound sources in fallers' work environments. Using data from noise dosimetry synchronized with observations of fallers' chain saw use, a model of sound pressure levels predictive of chain saw operating mode was developed. Subsequent workday noise histories of 13 fallers showed that the chain saw was off for an average of 331 +/- 27 min, idling for 91 +/- 11 min, and cutting wood for 96 +/- 7 min. This method could be used to collect data to refine dose-response estimates for vibration syndrome or to monitor administrative controls of vibration exposure time.

British Columbia↗
PubMed1989

The percutaneous fate of the rodenticide flocoumafen in the rat: role of non-biliary intestinal excretion.

1. Appreciable penetration of radioacticity occurred through rat skin following percutaneous administration of 14C-flocoumafen. At 7 days after dosing 12% of the administered radioactivity remained at the site of application, while 25% was located in the liver as unchanged flocoumafen. 2. Excretion of flocoumafen metabolites via the urine accounted for 10% dose over the 7 day experiment, this is some 30-fold greater than that seen after a single oral dose. 3. Unchanged flocoumafen comprised the major product detected in faeces. Biliary elimination was a very minor route of excretion and did not account for all of the unmodified flocoumafen present in faeces. 4. Considerable amounts of unchanged flocoumafen found associated with the contents of the large intestine after intraperitoneal administration to rats fitted with biliary fistulae indicates that, in the intact rat, flocoumafen enters the intestine by a non-biliary intestinal excretion mechanism.

4-Hydroxycoumarins↗
PubMed1989

Passive smoking by asthmatics: its greater effect on boys than on girls and on older than on younger children.

In 415 nonsmoking asthmatic children who were seen consecutively, asthma symptoms were more severe if the mother was a smoker than if she was a nonsmoker. This applied to both sexes but was more marked in boys than in girls. There were also other indications that sons were the more severely affected: the forced expiratory volume at 1 second, the forced expiratory flow rate during the middle half of the forced vital capacity, and the provocation concentration of histamine needed to result in a 20% decrease in the forced expiratory volume at 1 second were significantly decreased only in the sons, and lung function test results were significantly less in sons than in daughters of mothers who smoked. When the 415 children were stratified according to age, lung function improved significantly with increasing age in the children of nonsmokers; in children of smokers, by contrast, symptoms and lung function test results became progressively worse. As well, there was a correlation between these indications of asthma severity and the number of years the child had been exposed to the mother's smoke. It appeared that, compared with girls, boys were more sensitive to passive smoking, and that its adverse effect increased with age and with duration of exposure.

Adolescent↗
PubMed1988

Passive smoking and the seasonal difference of severity of asthma in children.

To learn whether asthmatic children are affected by passive smoking, we studied 240 unselected consecutively referred asthmatic subjects, aged 7 to 17 years. To discover whether children of smokers are affected more severely during the cold, wet season, when windows are closed and children are indoors, than during the warm, dry season, when houses are well ventilated and children spend more time outdoors, we compared lung function tests recorded during the two seasons. If seen during the cold, wet season, children of smoking mothers compared with those of nonsmoking mothers had a lower FEV1% (74 vs 86, p = .00), FEF25-75 percent (56 vs 75, p = .00) and PC20 histamine (0.85 vs 1.95, p = .01). There was a highly significant correlation between the number of cigarettes the mother smoked in the house and each of these lung function test results, indicating a dose-response relationship. Those seen during the warm, dry season, by contrast, did not have lower mean spirometric test results if their mothers were smokers than if nonsmokers, and there was no correlation between the number of cigarettes the mother smoked in the house and the result of any lung function test. Our results strongly support the hypothesis that cigarette smoke from the mother aggravates her child's asthma.

Adolescent↗
PubMed1987

Patient compliance with screening for fecal occult blood in family practice.

Thirty-two family physicians in British Columbia collaborated in a study to evaluate their patients' compliance when offered testing for fecal occult blood (FOB) with Hemoccult II as a screening test for asymptomatic colorectal cancer. Of the 5003 eligible patients 71% complied. Thirteen variables were investigated. Compliance was found to be directly related to age in a linear manner (chi-squared value for trend = 180.4, p less than 0.0001), age alone correctly classifying 58.5% of the patients as complying or not complying. The association with other variables was less strong. Restricting the consumption of red meat during the test period had no effect on compliance.

Age Factors↗
PubMed1987

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)

Adult↗
PubMed1987

Mandibular dysfunction in an institutionalized and predominantly elderly population.

Oral health problems were identified among 653 residents of 40 long-term care institutions in Vancouver, using a personal interview and a dental examination. Information on jaw function was analysed as part of this investigation to identify associations between the clinical signs of mandibular dysfunction and the complaints of the subjects, their occlusal instability, and the quality of their dentures. The sample population were predominantly female and over 75 years of age, and 42% had some natural teeth. Complaints of jaw dysfunction, usually sore muscles, were heard from 13% of the 488 subjects interviewed. The examination was performed on all of the subjects and revealed that 43% had unstable occlusal contacts, 37% were using loose or unstable dentures, and 20% had one or more clinical signs of jaw dysfunction. Joint noise was the most frequent sign detected and it was heard in a greater percentage of the women than men, while deviation of the mandible during mouth opening was observed with great frequency in the younger age groups. There was no apparent association found between the clinical signs of jaw dysfunction and the complaints of the subjects or the condition of their teeth or dentures. The study demonstrated that complaints and clinical signs of jaw dysfunction, with the exception of joint noises, were uncommon in this population.

Adult↗
PubMed1987

Factors influencing oral health in long term care facilities.

In a stratified random sample of 41 long term care (LTC) facilities in Vancouver, 653 residents were chosen to investigate oral health needs and demands for treatment. All of the 603 dentists in the same area were questioned to assess their interest in attending the residents of the institutions. The information from each source was reviewed to identify factors influencing the oral health services to this predominantly elderly and medically compromised population. The majority (60%) of the residents were edentulous and they made infrequent demands on dentists. Two-thirds of those interviewed said that there was nothing wrong with their mouths, but most of those who were aware of a problem wanted it treated, preferably within the institution. They complained about loose or uncomfortable dentures most frequently, and many were dissatisfied with previous dental treatment. The oral mucosal lesions seen on examination were usually symptomless and associated with poor hygiene, while structurally defective dentures and deep carious lesions were not uncommon. The responding 334 dentists indicated that they enjoyed treating elderly patients, 19% had attended an LTC facility, usually to provide an emergency service, and 37% were willing to provide this service if asked. Interest, however, in the service was curtailed by pressures from private practice, concerns about inadequate training and the small demand and poor conditions in the facilities. Although the demand for treatment was not extensive from the residents, they did have problems that were not receiving care.

Aged↗
PubMed1986

Vaginal colonization with Escherichia coli in healthy women. Determination of relative risks by quantitative culture and multivariate statistical analysis.

The rate of vaginal colonization with Escherichia coli in 495 healthy women was 12% in a prospective study with use of selective media and semiquantitative culture techniques. Computer-assisted multivariate analysis revealed that vaginal E. coli was significantly associated with the menstrual phase of the cycle, prior use of antibiotics, use of diaphragm or cervical cap for contraception, history of previous urinary tract infection, and coisolation of Staphylococcus aureus that was positive for the toxic shock syndrome toxin-1 (p less than 0.05, multiple stepwise logistic regression analysis). No significant association was observed with tampon use or brand, other contraceptive methods, sexual activity, genital symptoms, recent vaginal infection, or other personal habits. Quantitative cultures obtained sequentially throughout the menstrual cycle in 12 unselected women confirmed higher E. coli counts in menstrual or midcycle samples compared to paired premenstrual specimens (p less than 0.05, Wilcoxon paired rank sign test). These data emphasize the hormonal and other host determinants in vaginal colonization by E. coli and may explain the high rate of vaginal E. coli (64%), in addition to toxicogenic S. aureus, in acute toxic shock syndrome and the higher incidence of urinary tract infection in women with diaphragm or cervical cap for contraception compared to other contraceptive methods.

Adult↗
PubMed1986

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 child's asthma.

Adolescent↗
PubMed1985

Sensitization to house dust mites in different climatic areas.

With the use of local meteorologic data, the mean monthly indoor relative humidity (RH) was calculated for the area of residence of each of 774 children with respiratory symptoms who were referred to our allergy clinic. Seven hundred fourteen children lived in areas in which the mean indoor RH was 50% or more for 4 or more mo per year ("humid" areas), and 60 children lived where this RH was present for no more than 2 mo per year ("dry" areas). Of those children from the "humid" areas, the skin prick test was positive to Dermatophagoides farinae in 31% and D. pteronyssinus in 40%, whereas in those children from "dry" areas, tests were positive in 3% and 2%, respectively, (p less than 0.001). There was also a marked difference in the degree of sensitivity. In those children with a positive RAST (more than 12% of binding relative to allergen-specific pooled reference sera), the mean level of binding was 51% +/- 3.5% for D. farinae and 62% +/- 4.4% for D. pteronyssinus in children from "humid" areas but never exceeded 14% for either species in those children from "dry" areas (p less than 0.001). Sensitivity to D. farinae and D. pteronyssinus is frequent in "humid" areas and seldom, if it is ever, occurs in areas that are "dry," either as a result of a semiarid climate or a prolonged heating season. These findings have implications for the etiologic diagnosis and specific treatment of atopic patients living in different climatic regions.

Child↗
PubMed1985

The metabolism of n-butyl glycidyl ether in the rat and rabbit.

[1-14C]Butyl glycidyl ether administered orally to male rats and rabbits (20 mg/kg) is rapidly absorbed and metabolized. Most of the administered compound, 87% (rat) and 78% (rabbit), is eliminated in the 0-24 urine. Major metabolites in the rat include 3-butoxy-2-hydroxypropionic acid (9%), 3-butoxy-2-acetylaminopropionic acid (23%) and butoxyacetic acid (10%). 3-Butoxy-2-hydroxypropionic acid (35%) and butoxyacetic acid (5%) are also major metabolites in the rabbit. Biotransformations of the glycidyl ether and their likely biochemical mechanisms are discussed.

Animals↗
PubMed1984

2,4-Difluoroaniline and 4-fluoroaniline exposure: monitoring by methaemoglobin and urine analyses.

Two possible methods for monitoring exposure to 2,4-difluoroaniline and 4-fluoroaniline have been investigated: measurement of methaemoglobin content in blood and measurement of urinary metabolites. Experiments using rats dosed by the oral route as a model system show that measurement of methaemoglobin content provides a very rapid and simple monitoring method, but is not very sensitive. Measurement of the ortho-hydroxy metabolites of the two compounds, as their benzoxazole derivatives, provides a much more sensitive, but complicated technique. Details of both methods are presented.

Aniline Compounds↗