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Biomedical subjects

P Boucher

Publications and source records attributed to P Boucher.

At least 19 recordsLinked to original sources
PubMed1990

Occurrence of 222Rn and progeny in natural gas processing plants in western Canada.

In Western Canada, there are many plants that process natural gas to remove impurities (CO2, H2S, H2O) and recover natural gas liquids (propane, butane, etc.). Trace quantities of 222Rn present in the inlet stream are concentrated in streams rich with propane. Potential hazards to plant operators include direct inhalation of 222Rn and progeny; exposure to gamma radiation from short-lived progeny deposited inside equipment; or inhalation of 210Pb when contaminated equipment is opened for repair. Twenty-four plants operated by seven companies cooperated to assess these potential hazards. The findings indicate a substantial flux of 222Rn and progeny passing through the plants, but little accumulation of radionuclides. In no case was there evidence of significant exposure of plant operators or maintenance personnel to ionizing radiation. Further investigation of pipeline operations, and chemical operations using natural gas liquids as feed stock, is recommended.

Bismuth↗
PubMed1990

Mapping of functional domains within the v-erb A oncogene protein: the remnants of the hormone binding domain play multiple, vital roles in protein action.

The v-erb A oncogene represents a virally-transduced variant of a thyroid hormone receptor. Biochemical characterization of a series of mutant v-erb A proteins demonstrates that nuclear localization and DNA binding are both necessary for v-erb A function in the neoplastic cell and are mediated by multiple, overlapping domains within the v-erb A polypeptide. Domains of the v-erb A protein necessary for sequence-specific and sequence-independent DNA binding are distinguishable from one another, and encompass sequences projecting beyond the zinc-finger motifs themselves. Although unable to bind T3 thyroid hormone, the remnants of the hormone binding domain continue to play unanticipated essential roles in v-erb A protein function.

Cell Nucleus↗
PubMed1989

Myocardial perfusion imaging with a new radiotracer, technetium-99m-hexamibi (methoxy isobutyl isonitrile): comparison with thallium-201 imaging.

Technetium-99m-hexamibi (methoxy isobutyl isonitrile) is a Tc-99m-hexakis analog that can be used as a myocardial perfusion imaging agent. This is a report of an initial study that was performed in four institutions to assess the feasibility of Tc-99m-hexamibi myocardial imaging for the detection of coronary artery disease in patients undergoing treadmill stress test. Thirty-three patients referred for evaluation of chest pain had two exercise stress tests, one with Tl-201 and at least 24 hours after, and a second one with Tc-99m-hexamibi. Myocardial planar imaging started 60 minutes after injection at stress of 10-20 mCi of Tc-99m-hexamibi. Because this agent does not redistribute in myocardium after a stress injection, a second injection of 10-20 mCi of Tc-99m-hexamibi was performed with the patient at rest a few days later. Qualitative assessment of both Tl-201 and Tc-99m-hexamibi myocardial distribution was performed in 297 left ventricle segments (three segments of each of three views). There was a good correlation for the presence of normality, scar, or ischemia with the two radiopharmaceuticals, both on a segment by segment (259/297, or 87.2%) and patient-by-patient basis (29/33, or 87.9%). The number of segments found ischemic with Tl-201 and with Tc-99m-hexamibi were nearly equal, as were the number that were normal with one radiopharmaceutical and ischemic by the other. This initial study demonstrates that it is possible to detect stress-induced abnormalities of myocardial perfusion with Tc-99m-hexamibi similar to Tl-201 imaging.

Adult↗
PubMed1989

[Lepromatous leprosy: clinical and electrophysiological arguments in favor of axonal multi-neuritis].

UNLABELLED: This work was undertaken because there were only few reports on neurological aspects on lepromatous leprosy. We studied 30 patients suffering from lepromatous leprosy who, at their first visit to the Institute had never been treated. The clinical examination included a quantitative evaluation of the neurological status following the method developed by Pearson. Motor and sensory nerve conduction velocities were measured: values of conduction velocity and distal amplitude were analysed and compared to those of a group of 22 healthy subjects. IN CONCLUSION: (a) There is a high frequency of clinical and especially electrophysiological neurological impairment. This impairment can be extremely precocious and may happen shortly after the first cutaneous signs. (b) Nervous impairment is diffuse, bilateral but not homogeneous. These are characteristics of mononeuritis multiplex. Impairement is predominantly sensitive and tactile sensibility is more involved than thermo-algic sensation. (c) The radial superficial nerve is the most frequently involved clinically and electrophysiologically. (d) The electrophysiological results, showing a normal or slightly reduced conduction velocity and a low amplitude of evoked potentiel are in favour of a predominantly axonal damage.

Axons↗
PubMed1988

The avian erythroblastosis virus erbA oncogene encodes a DNA-binding protein exhibiting distinct nuclear and cytoplasmic subcellular localizations.

The protein product of the v-erbA oncogene of avian erythroblastosis virus was analyzed by use of site-specific antisera. The v-erbA protein was found to exist in distinct nuclear and cytoplasmic forms. Both nuclear and cytoplasmic species of the v-erbA protein were capable of binding to DNA, a property predicted based on the structural relatedness the v-erbA polypeptide shares with the thyroid and steroid hormone receptors. A mutation within the v-erbA coding region which inhibited DNA binding and nuclear localization also inhibited the ability of the v-erbA protein to potentiate erythroid transformation, consistent with a model of the v-erbA protein as a transcriptional regulator.

Alpharetrovirus↗
PubMed1988

Genetic dissection of functional domains within the avian erythroblastosis virus v-erbA oncogene.

The avian erythroblastosis virus v-erbA locus potentiates the oncogenic transformation of erythroid and fibroblast cells and is derived from a host cell gene encoding a thyroid hormone receptor. We report here the use of site-directed mutagenesis to identify and characterize functional domains within the v-erbA protein. Genetic lesions introduced into a putative hinge region or at the extreme C-terminus of the v-erbA coding domain had no significant effect on the biological activity of this polypeptide. In contrast, mutations introduced within the cysteine-lysine-arginine-rich center of the v-erbA coding region, a DNA-binding domain in the thyroid and steroid hormone receptors, abolished or severely compromised the ability of the viral protein to function. Our results suggest that the mechanism of action of the v-erbA protein in establishing the neoplastic phenotype is closely related to its ability to interact with DNA, presumably thereby altering expression of host target genes by either mimicking or interfering with the action of the normal c-erbA gene product.

Alpharetrovirus↗
PubMed1987

[Remote results of the surgical decompression of the posterior tibial nerve in the neuropathies of Hansen's disease].

Results are reported of surgery to the posterior tibial nerve affected by leprosy in 50 patients. A total of 90 neurolyses were performed using a similar technique. Study of the effect of surgery on the course of plantar sensitivity showed that 3 groups of nerves can be distinguished. Nerves in group 1 (21 totally paralyzed nerves) responded poorly to surgery (38% useful results) while on the contrary nerves in group 3 (non-paralyzed nerves) represented the ideal indication, surgery being truly prophylactic. In group 2 nerves a useful result was obtained in 82%. Indications for use of this surgical procedure are discussed, and more particularly the parameters affecting the quality of the results: severity of lesion, immunologic type of disease.

Adolescent↗
PubMedDate not supplied

[Multi-drug therapy trials for leprosy in Senegal: first observations relative to liver tolerance of multibacillary patients. Therapeutic consequences].

The authors have studied tolerance of multibacillary patients to 4 MDT regimens. These 4 regimens consist of: One supervised part in which RMP-ETH combination in once-monthly administered; furthermore, in 2 of these regimens, is included one "starter phase" with daily doses of that combination for 2 months. One self-administered part during which CLO is associated either to DDS for new cases, or to ETH for relapses. Clinical Supervision: Out to 310 multibacillary patients, 7 cases of hepatitis with or without icterus, but no death due to the treatment. Interruptions of MDT have been temporary and have been observed in 0.9 to 5.6% of the patients according to the therapeutic regimen. Checking SGOT: The SGOT were abnormally high in 16.3% of the patients before treatment. These pre-existing liver damages do not favour the appearance of intolerance disorders. During MDT, abnormal increases in SGOT are observed in 27% of the patients but there is no exact correlation between the absorbed doses of ETH and the frequency in SGOT increases. The clinical or biological evidence of liver damages occur rather early (1st, 2nd month) in regimens with "starter phase", and later (4th-8th month) in those without "starter phase". But introduction of "Starter phase" does not increase the global frequency of such intolerance accidents. ETH combined with RMP, must be used under steady clinical and biological supervision. Recalling the results of a previous survey, the authors consider that a long duration of MDT is not necessary. For the multibacillary leprosy treatment, they propose a diphasic regimen, more easily applicable in the field than the WHO protocols. In this diphasic regimen, the only part which must be supervised is the initial "starter phase" of 2 month. It consists of daily administration of 3 antibacillary drug among which RMP and ETH. The second phase is a relay treatment using 2 drugs, CLO combined with DDS or ETH, self-administered until smear negativity.

Adolescent↗