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Biomedical subjects

H David

Publications and source records attributed to H David.

259 records · Page 15Linked to original sources
PubMedDate not supplied

Importance of experience for older home care workers in facing up to the constraints of work.

Home care workers (HCWs) are at risk from injury. A case study was undertaken in a local community health center in order (1) to identify the constraints that introduce risk into the work of HCWs, and (2) to study the strategies they apply, depending on their age, to reduce the effects of those constraints. Observation and semistructured interviews were the main sources of data. Analysis shows that HCWs aged 45 or over sometimes adopt different postures from those used by their younger colleagues. During physical care, the HCWs also carry out screening and social support tasks that are not recognized in the organization of their work. Older workers develop strategies that help them save time, refine their screening and support methods, protect themselves against accidents, and react properly in emergencies or dangerous situations. Because the changes that can be made in patients' homes are limited, the expertise of experienced HCWs is essential. The organization of work must maintain a certain flexibility to allow the workers to use their strategies.

Accidents↗
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[Mycobacterium fortuitum infection after total hip prosthesis. A report of 3 cases (author's transl)].

The authors have observed three instances of sepsis due to Mycobacterium fortuitum complicating total hip replacement for osteoarthritis. The case histories are fully described. The requirements are given for recognition of the organism which grows on special culture media and which may be mistaken for Mycobacterium tuberculosis. This feature explains why, in some cases, the organism may not be discovered. Antibiotics were ineffective but the general condition of the patient was not greatly affected.

Aged↗
PubMedDate not supplied

[Taxonomic value of mycobacterial fatty acids: proposal for a method of analysis].

A simple and quantitative method for the alkaline hydrolysis of fatty acid derivatives occurring in the lipids of mycobacteria is described. After methylation, the lipidic mixtures were chromatographed on a thin layer of silicagel. The contents in mycolates and secondary alcohols allowed the distinction of 9 groups among the 27 species studied. Such an analysis is generally insufficient to identify a species, but its discriminating power differs from that of other commonly-used methods. Complementary tests chosen according to each particular situation are necessary, including vapour phase chromatography applied to the same lipidic mixture as that used for thin-layer chromatography. Coupling of the two chromatographic methods would allow the recognition of 22 groups among the 27 species of mycobacteria studied.

Chromatography, Gas↗
PubMedDate not supplied

[Lipidic constituents of "Mycobacterium leprae" isolated from experimentally infected armadillo (author's transl)].

Mycobacterium leprae (obtained from experimentally infected armadillo) was submitted to saponification. The liposoluble part was methylated and fractionated by chromatographic methods. Each fraction was studied by gas-liquid chromatography. Cholesterol (from the infected host) and the main fatty acids were identified. Mycolic acids were isolated, and their structures determined, using mass spectrometry. These structures are useful to make a comparison of M. leprae with some other mycobacteria. Some of these comparisons are discussed here. The absence-or, at least, the very low level-of tuberculostearate suggests comparative studies of M. leprae and M. gordonae.

Animals↗
PubMedDate not supplied

The pulmonary valve. Is it mechanically suitable for use as an aortic valve replacement?

Pulmonary autografts have shown a low incidence of early failure and late structural deterioration when placed in the aortic position yet the potential value of the pulmonary valve as a replacement device has not been widely considered. Since the mechanical suitability of pulmonary valves for the high stress aortic position is unclear, we set out to define and compare the tensile mechanical properties of these two valves. We removed all 72 cusps from 12 fresh porcine aortic and pulmonary valves. Eighteen cusps from each of the two groups were fixed flat in 0.25% glutaraldehyde for greater than 24 hr. Circumferential or radial strips were cut from each cusp creating eight test groups, each with nine specimens. Stress-strain curves for each specimen were obtained using an Instron tensile testing machine. Stress-strain curves were obtained at 2, 10, 50, and 200 mm/min strain rates, each specimen was then strained to fracture. We found pulmonary leaflets were thinner than aortic leaflets (0.49 mm versus 0.67 mm) and glutaraldehyde fixation did not affect this relationship. The elastic moduli were comparable within the fresh and glutaraldehyde fixed treatment groups and within the circumferential and radial strip groups. Radial strips were more extensible than circumferential strips. Tissue viscous properties were similar and glutaraldehyde fixation produced minimal changes in stress relaxation rates. Tissue fracture tests emphasized tissue anisotropy with the failure point depending upon strip orientation. Glutaraldehyde had no effect on fracture stress but strain at fracture doubled due to increased collagen fiber crimping during fixation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗