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Biomedical subjects

J Piché

Publications and source records attributed to J Piché.

12 recordsLinked to original sources
PubMed2000

Bile Salt Anion Sorption by Polymeric Resins: Comparison of a Functionalized Polyacrylamide Resin with Cholestyramine.

Cholestyramine and a cross-linked polyacrylamide resin with lateral alkyl quaternary ammonium groups (QPDA12) were used to study their ability to bind several bile salt anions (including the cholate, glycocholate, taurocholate, and chenodeoxycholate), individually and competitively, from phosphate buffer solutions at room temperature. The latter resin showed high affinities for all the bile salt anions examined, while cholestyramine exhibited a high affinity only for the more hydrophobic chenodeoxycholate. However, for the binding with cholestyramine, cooperative effects were more pronounced, leading to the enhancement of sorption at higher concentrations. The Langmuir equation and its modified versions were used in the interpretation of both individual and competitive binding of bile salts. The data from competitive binding studies indicated that the presence of the tightly bound chenodeoxycholate did not significantly diminish the ability of QPDA12 resin to bind cholate. However, for cholestyramine, the sorption of chenodeoxycholate increased the relative binding affinity for the more hydrophilic cholate, revealing a novel "cooperative" effect involving different bile salt anions. The latter results suggest that the observed higher affinity of QPDA12 is brought about predominantly through the hydrophobic interactions with the pendant alkyl groups rather than with the resin backbone. Copyright 2000 Academic Press.

Journal Article↗
PubMed1996

Pleomorphic soft tissue myogenic sarcomas of adulthood. A reappraisal in the mid-1990s.

325 diverse sarcomas, 39 rhabdomyosarcomas (RMS), including all histologic variants, and 135 leiomyosarcomas (LMS) were identified. Within these two groups, 18 (46%) of the RMS and 14 (10%) of the LMS represented pleomorphic variants. These neoplasms were studied by morphology (histology and ultrastructure) and by immunohistochemical methods employing antibodies to intermediate filaments (vimentin and desmin) and actin isoforms [alpha-smooth (sm) and alpha-sarcomeric (sr) actins]. Twenty-four pleomorphic malignant fibrous histiocytomas (MFH) and eight pleomorphic liposarcomas (LS) were examined in a similar fashion. By light microscopy, the pleomorphic RMS, LMS, and MFH were indistinguishable, as each was dominated by pleomorphic cells disposed in a haphazard growth pattern; moreover, many featured fascicular, storiform, and sclerotic zones. The distinction between these neoplasms became apparent only following immunohistochemistry and/or ultrastructural study. All pleomorphic RMS disclosed rudimentary sarcomeres and exhibited the following cytoskeletal profile: vimentin (+) (18 of 18), desmin (+) (14 of 18), alpha-sr actin (+) (18 of 18) and alpha-sm actin (+) (five of 18). All the pleomorphic LMS featured smooth-muscle differentiation of variable degrees in the form of cytoplasmic bundles of microfilaments and associated dense bodies; their cytoskeletal profile was vimentin (+) (14 of 14), desmin (+) (seven of 14), alpha-sr actin (+) (none of 14), and alpha-sm actin (+) (eight of 14). The latter was demonstrated in all moderately differentiated, but absent or only focally expressed in poorly differentiated variants. All pleomorphic MFH and LS were devoid of myogenic (skeletal or smooth) ultrastructural features and expressed vimentin solely. This combined morphological and immunohistochemical study illustrates the following: First, these pleomorphic sarcomas are often indistinguishable by histologic growth pattern alone; thus, an accurate diagnosis requires study with all of these techniques. Second, pleomorphic myogenic sarcomas are restricted to adults and are not uncommon neoplasms among pleomorphic sarcomas: RMS (28%), LMS (21%), MFH (38%), and LS (13%). Third, the study defines desmin-negative and alpha-sm actin-positive pleomorphic RMS, and desmin-negative and alpha-sm-actin-negative pleomorphic LMS.

Actins↗
PubMed1996

Snoring, apnea, and nasal resistance.

OBJECTIVE: To understand the impact of the nose in relation to snoring, to increased and decreased nasal resistance and sleep, to nasal anatomy and physiology in snorers and apneic patients, and to nocturnal episodes of respiratory obstruction in relation to nasal obstruction. DESIGN: A select group of patients, in whom nasal reconstruction and uvulopalatopharyngoplasty (UPPP) were combined, were studied. A review of the literature is included. METHODS: A questionnaire was given to all patients. MAIN OUTCOME MEASURES: Patients' snoring improvement was evaluated postoperatively. RESULTS: Overall, 174 of the 180 patients (97%) believed their snoring to be improved postoperatively after combined nasal reconstruction and UPPP were done. CONCLUSION: A review of the literature, a review of snorers' pathophysiology, and the results of this study show that nasal surgery and UPPP combined are effective in improving snoring.

Airway Resistance↗
PubMed1989

[Snoring: physiopathology, surgical treatment and a modified uvulo-palato-pharyngoplasty].

Sleep apnea, now recognized as a specific clinicopathological entity, had received little attention until late 1960 when described by Gastaud. Since that time, following the works of Ikematsu, Guillemineault and Fujita, there has been rapid extension in the knowledge and understanding of sleep problems and associated surgery. Snoring, whether part of the sleep apnea syndrome or alone, may be explained with the help of an aerodynamic model comparing the pharynx to a Starling resistance. The factors nasal obstruction, abnormal mass in the upper respiratory airways and transmural resistance are discussed in the light of this model. To modify some of the above factors, surgical techniques have been described. We feel these conventional techniques do not take into account the normal healing process of inverted double C scars. We have modified the classic technique by sectioning the palatopharyngeus muscle and used Z-plasty to close the surgical defect. This is followed by a limited resection of the soft palate. As a consequence, the soft palate is being brought forward in the healing process and the oropharynx AP diameter is enlarged. This minimal type of resection of the soft palate precludes complications of velopharyngeal incompetency or relative pharyngeal stenosis. We have studied 200 snorers and operated on 90 of them, 25 according to the standard technique and 65 with the modified technique. The modified technique, while limiting the amount of palate to be removed and also the morbidity, is easy to standardize and offers as good results with fewer risks.

Adult↗
PubMed1987

Health problems of data entry clerks and related job stressors.

A study was made of health problems reported by data entry clerks working in two large data pools within the Québec Public Service Administration. In order to collect the data, 350 clerks answered a questionnaire, representing a return rate of 92%. The results indicate that, in comparison with women in other occupations, the data entry clerks have a high rate of occurrence of psychiatric symptoms (measured by the Ilfeld index) as well as a high degree of use of over-the-counter and prescription drugs. In addition, these two problems are more prevalent in full-time clerks than in part-time clerks. The psychiatric symptoms appear related to the combined influence of two main factors: work overload and the monotony of work specialization. A third factor, the quality of the relationships among workers in the pool, also seemed to affect the regular full-time clerks.

Adult↗
PubMed1985

[The organization of work and the mental health of nurses aides.].

The aim of this article is to focus on the problems encountered by auxiliaries collecting data within the frame work of a certain organization of work. A questionnaire was distributed to two big groups in the public sector. It was answered by three hundred and fifty auxiliaries with a 92% rate of response. In comparison with other jobs occupied by women, these auxiliaries present a much higher incidence of depressive or anxious symptoms and of drug abuse. The recourse to a regressive model helps to explain the results by the combined effect of two factors amongst others: first, by a strong pressure to perform and then by the monotony of piecework. It is possible that the alienation symbol of the last two decades is not the worker at the assembly line but, with the preponderance of computerised office, is now the woman reducing to the collection of date.

English Abstract↗