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Biomedical subjects

B J Morrison

Publications and source records attributed to B J Morrison.

At least 19 recordsLinked to original sources
PubMed1997

A reason why measures to avoid mite-induced asthma are more effective in children than in adults.

Mite-sensitive asthmatics seem to respond more markedly to a reduction in mite allergen in the bedding if they are children than if they are adults. In order to investigate this difference, 882 children who attended our allergy clinic were studied. The accompanying parents were asked standardized questions, and skin prick tests to Dermatophagoides pteronyssinus and D. farinae were performed on the children. The number of hours that the children spent in bed lessened progressively with increasing age, from a mean of 13.6 hrs. for 1 year olds to 9.5 hrs for 17 yr olds: the mean for the total population was 12.0 hrs. This was significantly longer than the mean for the parents, 8.4 hrs (p=.000). It is likely that a longer period of exposure to mite allergen in bed is an important reason why children respond more markedly to avoidance measures in the bedroom than adults do.

Adolescent↗
PubMed1996

Mycoplasma pneumoniae reinfection and vaccination: protective oral vaccination and harmful immunoreactivity after re-infection and parenteral immunization.

Animal model studies of Mycoplasma pneumoniae infection after live respiratory challenge were conducted to investigate the issues of challenge-rechallenge associated accentuated pathology, postparenteral vaccination associated accentuated pathology, and oral vaccination. Live M. pneumoniae inocula were grown in hamster serum-based medium in order to reduce the potential for the serum growth component to participate in the hyperaccentuated histopathological response as seen with challenge-rechallenge experiments which have used horse serum-based growth media. Despite the use of homologous animal serum, an early hyperaccentuated response occurred (day 3 score 13.3 vs day 10 score 7.7; P = 0.02) which included perivascular infiltrates, and histopathological scores for early (day 3) and late (day 10) disease were similar (P > 0.10) between experiments of challenge-rechallenge when either homologous or heterologous sera were used in inoculum growth media. Parenteral vaccination with heat-killed bacteria also led to an early hyperaccentuated histopathological response after live respiratory challenge (scores on day 3: vaccinated 18.3, unvaccinated 6.2; P < 0.01) and this response was not significantly diminished when inocula were cleaned of growth medium components. An early accentuated response did not follow oral vaccination with heat-killed bacteria (score on day 3: vaccinated 5.7) and the late reaction was significantly less after challenge (scores on day 10: vaccinated 10.3, unvaccinated 14.6; P = 0.011). Studies of parenteral vaccination should include analyses for early disease after live challenge. Oral vaccination offers a promising route for stimulating protective immunity while minimizing undesirable recall immune events.

Administration, Oral↗
PubMed1996

Forty years of repeated screening: the significance of carcinoma in situ.

Two cohorts of women born in 1914-18 and 1929-33 who participated in a cervical screening programme have been followed for over 40 years. Age-specific incidence rates of squamous carcinoma of the cervix by rank of smear and length of interval between smears are reported. The younger cohort, who had undergone more frequent screening, had lower rates of invasive disease. From these incidence rates, estimates of false-negative rates and regression rates for carcinoma in situ have been made. The false-negative rate was estimated to be about 15%. Regression seemed more frequent in younger than in older women. For the younger cohort it was estimated to be 72% and in the older 47%. A comparison of the rates of in situ carcinoma with those of invasive disease suggests that the screening of the younger cohort reduced the rate of invasive disease to at least one-half or one-third of what it would have been if screening had commenced later. Rates of disease appear less dependent on age than previously thought and are consistent with causation by an infective agent.

Adult↗
PubMed1995

Orthodeoxia-platypnea due to intracardiac shunting--relief with transcatheter double umbrella closure.

The safety and efficacy of transcatheter clamshell occlusion of patent foramen ovale for relief of severe arterial desaturation and dyspnea in the upright position due to intracardiac shunting were examined in eight patients with excessive risk of surgical patent foramen ovale closure. All patients had successful reduction of intracardiac shunting with an immediate rise in oxygen saturation > or = 95% by implantation of a clamshell device on the atrial septum. Despite two early incidents of device embolization, retrieval and immediate re-implantation, and one patient with nonsustained atrial and ventricular arrhythmias, there were no adverse clinical sequelae. In follow-up evaluation transcatheter clamshell closure of patent foramen ovale has provided persistent relief from shunt-related arterial desaturation and symptomatology in all living patients.

Adult↗
PubMed1995

Bases for the early immune response after rechallenge or component vaccination in an animal model of acute Mycoplasma pneumoniae pneumonitis.

The pathology of Mycoplasma pneumoniae pulmonary infection for a hamster model was examined after whole bacterium rechallenge or component vaccination. Animals which, after an initial infection, were rechallenged with either live or heat-killed M. pneumoniae inocula developed severe early recall lesions in the first 3 days. In contrast, animals infected once develop maximum histopathology at approximately 10-14 days. A severe perivascular inflammatory cellular infiltrate developed in the rechallenged groups, and pulmonary pathology could also be elicited by rechallenge with bacterial growth medium components. Component vaccination with protein P1 did not reduce disease in comparison to once-infected controls, and vaccination promoted an early immune recall response as well. We conclude that an early immune response needs to be sought in all future experiments of challenge/rechallenge or vaccination. Vaccine studies will require an understanding of both protective and harmful immunogens.

Acute Disease↗
PubMed1994

Left atrial myxoma presenting as acute respiratory failure.

We report the unusual case of a young man with acute respiratory failure caused by a left atrial myxoma. The patient's rapid clinical deterioration and severe hypoxemia suggested the acute respiratory distress syndrome; however, unexpected physical examination findings and a markedly elevated pulmonary capillary wedge pressure implied cardiac abnormality. The use of echocardiography as a bedside tool allowed correct, rapid diagnosis.

Acute Disease↗
PubMed1994

A continuing assessment of risk factors for the development of Escherichia coli O157:H7-associated hemolytic uremic syndrome.

Univariate and multivariate analyses were applied to determine risk factors for the progression of Escherichia coli O157:H7 enteritis to hemolytic uremic syndrome (HUS). Both clinical and laboratory variables were assessed for 118 pediatric patients (28 HUS; 90 enteritis only). Verotoxins 1 and 2 were produced by 89% of E. coli strains whereas verotoxin 2 only was produced by 11%. Although a greater frequency of strains producing verotoxin 2 only occurred in HUS isolates (p = 0.11), toxin phenotype was not significantly associated with risk after multivariate analyses. HUS patients with or without neurological manifestations had similar frequencies of the two toxin phenotypes among their isolates. Significant associations for young age (RR = 0.984; 95% CI = 0.971-0.998) and prolonged use of antidiarrheal agents (RR = 44.11; 95% CI = 8.48-229.4) with HUS were apparent. A lesser chance of progression was observed for patients whose strains possessed a 4 kb plasmid (RR = 0.27; 95% CI = 0.08-0.94). Our results are consistent with the hypothesis that progression to HUS is dependent upon both bacterial virulence factors and the clinical characteristics of the individual patient.

Bacterial Toxins↗
PubMed1993

Rethinking work with "multicultural populations".

This article examines the importance of ethnic and cultural factors in mental health and mental illness, through consideration of race and culture in the diagnosis and treatment of mental illness, by examining patterns of service utilization by multicultural populations, and by advocating for policies which support multicultural initiatives in public mental health.

Cross-Cultural Comparison↗
PubMed1993

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 children's 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 child's 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 child's asthma, the child will be exposed to fewer cigarettes, and the asthma will be less severe.

Adolescent↗
PubMed1993

The influence of social, economic, and professional considerations on services offered by dentists to long-term care residents.

Many studies have focused on the disabilities and behavior of the elderly population in an attempt to explain the frequent reports of poor oral health among residents of long-term care (LTC) facilities, but little attention has been given to the experiences and opinions of dentists relating to the problem. This study was conducted to discover how dentists feel about older patients and about working in LTC facilities. A response to a questionnaire was obtained from 334 (55%) of the 603 dentists in Vancouver who treated adults. The responses were subjected to bivariate and multivariate analyses. Three models were constructed from factors that might interest a dentist in attending a patient in a facility; the factors in each model were ranked in order of importance. Interest was associated significantly with lack of concern for time lost in practice, with training in managing medically compromised patients, and with a positive attitude toward elderly patients. Dentists with fewer years in practice were attracted by the economic potential of the service, while the older and busier dentists were less involved because of the disruption to their practice and leisure. Dentists who made home visits also were more likely to be interested. The model based on professional considerations was superior to either the social or economic model in explaining an interest in the service.

Adult↗
PubMed1993

Ophthalmic artery flow velocity in glaucomatous and normal subjects.

The velocity of blood flow in the ophthalmic artery was measured with a transcranial Doppler ultrasound (2 MHz). Sixty patients with chronic open angle glaucoma (COAG), 42 patients with normal tension glaucoma (NTG), and 35 normals were studied. Peak flow velocity (peak), mean-enveloped velocity (mean) and diastolic velocity were compared in the three groups. The COAG patients and the NTG patients showed a significant reduction of all three Doppler flow velocities compared with the normals (COAG vs normal, p = 0.013, 0.019, and 0.009; NTG vs normal, p = < 0.001, < 0.001, and < 0.001 for peak, mean and diastolic flow velocity respectively). The NTG patients also had a significant slower mean flow velocity than the COAG patients (p = 0.016), but not for peak and diastolic flow velocities (p = 0.060 and 0.052 respectively). Based on ophthalmic flow velocity values, many NTG patients and a few COAG patients had slower flow velocities than the normals. The significance of these haemodynamic differences is not yet known.

Adult↗
PubMed1992

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 less than 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.

Acute Disease↗
PubMed1992

Opinions of dentists on the treatment of elderly patients in long-term care facilities.

The high prevalence of disorders in the mouths of elderly residents in long-term care (LTC) facilities suggests that the dental services available to the residents are inadequate. A questionnaire was sent to most of the dentists practicing in Vancouver (British Columbia) to solicit their opinions on treating older patients in LTC facilities, and a response was obtained from 334 (55%). It indicated that 19 percent of the respondents had treated old people within this context, although few of them felt they had been educated adequately for the service. Many reasons were offered to explain the small participation. Most respondents had never been asked to attend a facility. Many felt that it interfered with their practice and leisure, and they were concerned about the limited options available for treatment. Dentists who had attended facilities were motivated by a sense of professional or public responsibility, but they were uneasy about the limited options and about the inadequate space and equipment available. In general, the dentists were not interested in attending an institutionalized geriatric population, and they felt ill-prepared for the service.

Adult↗
PubMed1992

Effect of passive smoking on asthmatic children who have and who have not had atopic dermatitis.

We studied 240 children with asthma who were themselves nonsmokers and had been referred consecutively to our clinic. They were aged 6 to 17 years. The severity of asthma was assessed by symptom score, by spirometry, and, in those who could perform the test reliably, by histamine bronchial challenge test. Those who reported having had a chronic or chronically relapsing itchy rash in characteristic locations were recorded as having had atopic dermatitis. Multiple analysis of variance revealed that children whose mothers smoked had significantly more severe asthma (p less than 0.001) but that atopic dermatitis had no apparent effect on the severity of asthma, either in its main effect (p = 0.71) or in its interaction with maternal smoking (p = 0.66). Although our previous study indicates that smoking mothers' children are more likely to develop asthma if they have had atopic dermatitis than if they have not, the severity of asthma does not appear to be associated with a history of atopic dermatitis. In smoking mothers' children the asthma was just as severe in those who had not had atopic dermatitis as in those who had.

Adolescent↗
PubMed1992

Risk factors for the central nervous system manifestations of gastroenteritis-associated hemolytic-uremic syndrome.

Hemolytic-uremic syndrome is usually a consequence of enteric verotoxigenic Escherichia coli infection, and a prevailing hypothesis contends that systemically absorbed verotoxins are responsible for the multiple organ involvement. In an attempt to determine whether the central nervous system (CNS) manifestations could occur owing to factors that reflect a toxin insult, the authors studied the association of clinical and laboratory variables with the development of neurological disease. Ninety-one patients with hemolytic-uremic syndrome from 1982 through 1990 were included. Twenty-seven (18 female, 9 male) had a CNS disorder; 17 of these had seizures and there were two deaths. Multivariate analyses led to the following observations: female gender (odds ratio [OR] 8.50; 95% confidence interval [CI] 2.08 to 50.0), prolonged use of an antimotility pharmacological agent (OR 8.50; 95% CI 1.69 to 42.81), and an increased hemoglobin level (OR 1.11; 95% CI 1.05 to 1.17) were associated with an increased risk for developing a neurological manifestation. Prior administration of a blood product was associated with a decreased risk (OR 0.12; 95% CI 0.02 to 0.52). The findings suggest that other mechanisms for CNS disease may exist in addition to direct toxin insult.

Adolescent↗
PubMed1991

Beta-haemolytic non-group A streptococci and pharyngitis: a case-control study.

A case-control study was conducted to examine the association of beta-haemolytic non-group A streptococci and pharyngitis in a paediatric population (n = 502). No association could be found between disease and traditional Lancefield groups B, C, F, or G. When the analysis included the clustering of genetically related subgroups from different Lancefield groups, an association was evident for moderate and heavy quantitations of beta-haemolytic "large colony" group C and G streptococci (Streptococcus equisimilis and human biotypes of large colony group G streptococci) (p = 0.021). This study further defines a subset of the beta-haemolytic non-group A streptococci that merit recognition by both the laboratory and physician.

Case-Control Studies↗
PubMed1990

Health belief and compliance with screening for fecal occult blood.

Additional data regarding compliance with screening for occult bowel neoplasm using hemoccult II is reported in this paper. The effects of 'health beliefs' and 'barriers to compliance' among a subset of 256 compliers and 166 noncompliers drawn from the population of 5003 patients previously screened were analyzed. Health belief variables as predictors of compliance were found to be age related. Being 'too busy' was frequently given as the reason for noncompliance in all age groups. The percentage of patients correctly classifies as to compliance was appreciably higher than in the earlier study which considered demographic data and the effect of diet restriction. These findings carry implications extending into clinical practice.

Age Factors↗