Search PubMed⌕ Search

Biomedical subjects

M A Stewart

Publications and source records attributed to M A Stewart.

At least 19 recordsLinked to original sources
PubMed1992

Partial dissociation of subgroup C phenotype and in vivo behaviour in feline leukaemia viruses with chimeric envelope genes.

Feline leukaemia viruses (FeLVs) are classified into subgroups A, B and C by their use of different host cell receptors on feline cells, a phenotype which is determined by the viral envelope. FeLV-A is the ubiquitous, highly infectious form of FeLV, and FeLV-C isolates are rare variants which are invariably isolated along with FeLV-A. The FeLV-C isolates share the capacity to induce acute non-regenerative anaemia and the prototype, FeLV-C/Sarma, has strongly age-restricted infectivity for cats. The FeLV-C/Sarma env sequence is closely related to that of common, weakly pathogenic FeLV-A isolates. We now show by construction of chimeric viruses that the receptor specificity of FeLV-A/Glasgow-1 virus can be converted to that of FeLV-C by exchange of a single env variable domain, Vr1, which differs by a three codon deletion and nine adjacent substitutions. Attempts to dissect this region further by directed mutagenesis resulted in disabled proviruses. Sequence analysis of independent natural FeLV-C isolates showed that they have unique Vr1 sequences which are distinct from the conserved FeLV-A pattern. The chimeric viruses which acquired the host range and subgroup properties of FeLV-C retained certain FeLV-A-like properties in that they were non-cytopathogenic in 3201B feline T cells and readily induced viraemia in weanling animals. They also induced a profound anaemia in neonates which had a more prolonged course than that induced by FeLV-C/Sarma and which was macrocytic rather than non-regenerative in nature. Although receptor specificity and a major determinant of pathogenicity segregate with Vr1, it appears that sequences elsewhere in the genome influence infectivity and pathogenicity independently of the subgroup phenotype.

Amino Acid Sequence↗
PubMed1992

A survey method for investigating ethical decision making in family practice.

BACKGROUND: The tension between respect for patient autonomy versus concern for patient welfare is a challenging ethical issue for physicians. The purpose of this research was to describe a method for analyzing ethical decisions and to report the results of a survey of ethical decision making among family physicians. METHODS: We developed a survey instrument that used simulated case scenarios, each of which posed an ethical dilemma. The ethical problems on the survey included the extent to which diagnostic information should be revealed to patients, the extent to which physicians should become involved in patients' life-style issues, and how to deal with patients' family problems. We mailed the questionnaire to 1,300 US family physicians. RESULTS: Six hundred seventy-four physicians responded. Respondents did not deal with the simulated ethical problems in a uniform manner and often tended to respond more to specific details of a case rather than the overall ethical dilemma posed. Physicians who chose a course of action giving patients more control were motivated by factors that showed respect for patient autonomy. On the other hand, physicians who chose a course of action giving patients less control were not motivated by factors suggesting a concern for patient welfare. CONCLUSIONS: Based on responses to simulated case scenarios, family physicians did not demonstrate a uniform approach but rather a more contextual one. Respect for patient autonomy was linked to family physicians' reported courses of action.

Adult↗
PubMed1991

Ethical decision making by family doctors in Canada, Britain and the United States.

Family doctors in Canada and the U.S. and general practitioners in England and Wales were sent a questionnaire containing six cases that raised moral issues. The doctors were asked to select the most appropriate course of action for each case as well as reasons for that decision. The ethical problems concerned how much information to divulge to patients, how extensively a physician should become involved in the lifestyles of patients, and how to deal with a possible family problem. The respondents selected different courses of action for the cases. More U.S. than Canadian or British physicians chose to divulge information, while more British than Canadian or U.S. physicians chose not to become involved in patients' lifestyles. Physicians who chose to divulge information were likely to be young, male, live in a small community, and have no academic affiliation. Physicians who chose not to become involved in lifestyle issues were likely to be young, church attenders, and in group practice in a small community.

Beneficence↗
PubMed1990

Retinal detachment in penetrating keratoplasty patients.

We reviewed the records of 23 patients who had retinal detachment after penetrating keratoplasty. Seventeen retinas (74%) were reattached successfully. Of the six failures, four patients had hemorrhagic choroidal detachment at the time of keratoplasty. When these complex retinal detachments are subtracted, 17 of 19 patients (89%) had successful retinal reattachments. Of the 17 successes, only seven patients had visual acuity of 20/200 or better. Retinal detachments after penetrating keratoplasty can be repaired with a high rate of success, but visual results remain disappointing.

Cataract Extraction↗
PubMed1989

Patient-centredness in the consultation. 1: A method for measurement.

This paper presents a method for assessing the doctor-patient interaction in terms of its patient-centredness. Patient-centredness was defined in terms of doctor responses which enabled patients to express all of their reasons for coming, including symptoms, thoughts, feelings and expectations. The method was tested and found to be valid (correlations for criterion validity rs = 0.51 and 0.89), reliable (inter-rater correlation rs = 0.91, intra-rater correlation rs = 0.88), and sensitive, in that it was able to detect differences among doctors (P less than 0.001) and among doctor responses to different patient offers (P less than 0.001). The method was also found to be practical in that it was inexpensive and could be used for a variety of purposes such as by tutors to give feedback to their students, by examiners as part of the evaluation of candidates' consultation skills, and by students and clinicians alike, for self-assessment. The finding that the score for the first two minutes of the consultation correlated highly with the score for the entire consultation (rs = 0.806) greatly increases the time effectiveness of the method, suggesting that it would be practical for use on a large scale, including student assessment and future studies of the relationship between patient-centredness and patient outcomes.

Attitude to Health↗
PubMed1989

Subgrouping conduct disorder by psychiatric family history.

The family history of psychiatric disorders, and clinical and demographic characteristics of boys with pervasive aggressive conduct disorder (PACD) were compared to those of boys with situational aggressive conduct disorder and controls. Boys with PACD came from lower socioeconomic backgrounds, had an earlier age of onset, and higher rates of hyperactivity and inattention than boys in the other two groups. Their mothers abused drugs more often than those of boys in the other two groups, while their fathers had more frequent antisocial behavior. Alcohol abuse was more prevalent among fathers of both conduct disorder groups, compared to the fathers of controls.

Aggression↗
PubMed1989

Ethical decision making by British general practitioners.

General practitioners in England and Wales were sent a questionnaire asking how they would handle the ethical problems posed by six case vignettes and their reasons for their decisions. The ethical problems included: how much information to divulge to patients, how extensively a physician should become involved in the lifestyles of patients and how to deal with a possible family problem. The varying patterns of response to the six cases suggested that ethical issues are resolved in a case-by-case, not a theoretical, basis.

Beneficence↗
PubMed1988

The effect of psychosocial factors on lung cancer mortality at one year.

In this study newly diagnosed male and female lung cancer patients admitted to two Ontario Cancer Foundation treatment clinics were interviewed. Information was obtained on demographic variables, presence of other chronic illness and the following psychosocial attributes: locus of control, social support and personality traits. From the clinic charts, information on stage of disease and pathological diagnosis was obtained. After controlling for the effects of stage and pathological diagnosis, the following psychological variables were found to increase the odds of death from lung cancer among males and females combined at one year after diagnosis: a high need for one aspect of social support, a reserved personality and the extremes of the personality trait soberness vs enthusiasm.

Female↗
PubMed1987

Ethical decision making by Canadian family physicians.

Canadian family physicians were sent questionnaires that asked how they would handle the ethical problems posed by six sample cases and what reasons were relevant to their decisions. The ethical problems concerned how much information to divulge to patients, how extensively a physician should become involved in the lifestyles of patients and how to deal with a possible family problem. The study identified characteristics of family physicians that affect their ethical decision making and tested a theoretical model that regards ethical problems as conflicts between respecting patient autonomy and promoting patient welfare. The varied responses suggested that ethical issues are resolved on a case-by-case, rather than a theoretical, basis. Certification in family medicine was the only characteristic associated with a consistent pattern of responses; certificants were more likely than other physicians to involve patients in decisions.

Canada↗
PubMed1987

The effect of socioeconomic factors on the early prognosis of cancer.

Previous studies have suggested that cancer patients of low socioeconomic status (SES) have poorer short and long-term survival than cancer patients of higher SES. In this study male and female patients between the ages of 25 and 70, admitted to two Ontario Cancer Treatment and Research Foundation Clinics with newly diagnosed cancers of a number of common sites, were interviewed to obtain information on education and occupation, and chronic illnesses other than cancer. Information on stage of disease at diagnosis, exact pathologic diagnosis, date of diagnosis, and treatment before and after admission to the clinic was obtained from clinic charts. Using multiple logistic regression analysis to control for the effect of stage and other variables, there was no convincing evidence that cancer patients of low SES measured by either education or occupation had a less favourable outcome at one year after diagnosis from cancers of all sites combined or lung cancer specifically. The data suggested that any single measure of SES affects males and females differently.

Adult↗
PubMed1986

Conservation of the c-myc coding sequence in transduced feline v-myc genes.

We have cloned the normal feline c-myc locus and determined the nucleotide sequence of all three exons. The feline c-myc gene shows close homology to other mammalian c-myc genes, particularly human c-myc. The feline and human sequences are colinear within the open reading frame for the putative c-myc product but show insertions and deletions relative to each other outside this domain. We have also analyzed a cloned FeLV provirus, CT4, which contains the host-derived myc gene. In this provirus the v-myc sequences are located at the 3' end of the pol gene, replacing pol and env sequences. Nucleotide sequence analysis of CT4 shows an open reading frame for a v-myc gene product which may be expressed without fusion to any viral protein sequences. This contrasts with another FeLV v-myc (LC), in which myc and gag sequences were found to be fused. Unlike previously identified avian v-myc genes, the feline v-myc genes contain exon 1-derived sequences, but these have been truncated or internally deleted. The FeLV CT4 v-myc sequence shows very few coding changes relative to c-myc and the FeLV LC v-myc coding sequence is unchanged relative to c-myc apart from fusion to gag. These results are discussed in relation to the mechanism of transduction and activation of myc by FeLV.

Amino Acid Sequence↗
PubMed1986

The patient-centred clinical method. 1. A model for the doctor-patient interaction in family medicine.

This article describes a patient-centred clinical method appropriate for family medicine. The method is designed to attain an understanding of the patient as well as his disease. This two-fold task is described in terms of two agendas: the physician's and the patient's. The key to an understanding of the patient's agenda is the physician's receptivity to cues offered by the patient, and behaviour which encourages him to express his expectations, feelings and fears. The physician's agenda is the explanation of the patient's illness in terms of a taxonomy of disease. In the patient-centred clinical method, both agendas are addressed by the physician and any conflict between them dealt with by negotiation. This is contrasted with the disease-centred method in which only the doctor's agenda is addressed. Further articles will describe the patient-centred method in operational terms.

Aged↗
PubMed1986

Factors which predict the persistence of aggressive conduct disorder.

Fifty-three boys with aggressive conduct disorder were followed up 2 years after their original examination. Twenty-four (45%) no longer had the disorder and were classified as improved. A discriminant function analysis identified characteristics of the boys and their families which accurately predicted the outcome for 85% of the boys. Among the predictors of persisting conduct disorder were a variety of antisocial or aggressive symptoms, firesetting, early age of onset and family deviance.

Accident Proneness↗