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Biomedical subjects

A Manson

Publications and source records attributed to A Manson.

11 recordsLinked to original sources
PubMed1998

Correlation between varying levels of PMP22 expression and the degree of demyelination and reduction in nerve conduction velocity in transgenic mice.

Charcot-Marie-Tooth disease type 1A is most commonly caused by a duplication of a 1.5 Mb region of chromosome 17 which includes the peripheral myelin protein 22 gene (PMP22). Over-expression of this gene leads to a hypomyelinating/demyelinating neuropathy and to severely reduced nerve conduction velocity. Previous mouse and rat models have had relatively high levels of expression of the mouse or human PMP22 gene leading to severe demyelination. Here we describe five lines of transgenic mice carrying increasing copies of the human PMP22 gene (one to seven) and expressing increasing levels of the transgene. From histological and electrophysiological observations there appears to be a threshold below which expression of PMP22 has virtually no effect; below a ratio of human/mouse mRNA expression of approximately 0.8, little effect is observed. Between a ratio of 0.8 and 1.5, histological and nerve conduction velocity abnormalities are observed, but there are no behavioural signs of neuropathy. An expression ratio >1.5 leads to a severe neuropathy. A second observation concerns the histology of the different lines; the level of expression does not affect the type of demyelination, but influences the severity of involvement.

Animals↗
PubMed1996

Construction of a mouse model of Charcot-Marie-Tooth disease type 1A by pronuclear injection of human YAC DNA.

Construction of animal models of human inherited diseases is particularly important for testing gene therapy approaches. Towards this end, we constructed a mouse model for Charcot-Marie-Tooth disease type 1A by pronuclear injection of a YAC containing the human PMP22 gene. In one transgenic line, the YAC DNA is integrated in about eight copies and the PMP22 gene is strongly expressed to give a peripheral neuropathy closely resembling the human pathology. The disorder is dominant, causes progressive weakness of the hind legs, and there is severe demyelination in the peripheral nervous system including the presence of onion bulb formations. This approach will be valuable for pathologies produced by over-expression of a gene including trisomy and amplification in cancer. Such models will be particularly useful for testing gene therapy approaches if the transgene is human.

Animals↗
PubMed1991

Malnutrition in elderly ambulatory medical patients.

Elderly ambulatory persons may be especially susceptible to malnutrition, particularly those who are poor and socially isolated or have comorbid chronic medical diseases. We found that 98 of 2,986 persons aged 60 years or older attending a hospital-based medical practice between 1979 and 1989 weighed less than 45.4 kg (100 lbs). All but 1 of these subjects met criteria for malnutrition as judged against age-specific norms for weight. Thus the prevalence of malnutrition in this sample was 3.25% (95% CI 2.61, 3.89%). Interviews and physical examinations of a subsample (n = 16) revealed that all 16 subjects either met anthropometric-based criteria for malnutrition or were being treated for malnutrition. Of the 98 subjects who weighed less than 45.4 kg, 62 (63.3%; 95% CI 53.8, 72.8%) had comorbid conditions that could have contributed to malnutrition. Physicians did not record a diagnosis of malnutrition or weight loss in 47.9% of subjects (95% CI 38.0, 57.8%) and did not prescribe a nutrition supplement for 76.5% of subjects (95% CI 68.1, 84.9%). Subjects treated with nutrition supplement were more likely to have cancer. These findings suggest that malnutrition, both with and without concomitant major comorbid disease, is relatively frequent among elderly ambulatory patients and that a specific nutritional diagnosis is not made in many cases. We suggest that weight under 45.4 kg in an elderly person is a useful criterion for identifying elderly patients at nutritional risk.

Aged↗
PubMed1988

Language concordance as a determinant of patient compliance and emergency room use in patients with asthma.

To test the hypothesis that the ability of physicians to speak the same language as asthmatic patients promotes patient compliance and the use of scheduled office appointments in preference to emergency services, the charts of 96 Spanish-speaking patients with asthma were reviewed. Of these patients, 65 were cared for by seven Spanish-speaking bilingual physicians and 31 were cared for by 23 non-Spanish speaking physicians. Compared with patients with language concordant physicians, patients with language discordant physicians were only slightly more likely to omit medication, to miss office appointments, and to make at least one emergency room visit. Subgroup analysis showed that, with extended follow-up, patients cared for by a language discordant physician were more likely to omit medication (rate ratio: 3.24; p = 0.08), more likely to miss office appointments (rate ratio: 3.06; P = 0.01), and were slightly more likely to make an emergency room visit (rate ratio: 2.07; P = 0.12) than patients with language concordant physicians. Cox regression analyses taking account of differences in follow-up time, age, gender, pay-status, and severity of disease confirmed these findings. These data suggest that patient compliance and more cost-effective use of ambulatory care services may be associated with the ability of physicians to speak the same language as their patients.

Adult↗