PubMed Health⌕ Search

Biomedical subjects

B Marchand

Publications and source records attributed to B Marchand.

At least 19 recordsLinked to original sources
PubMed1992

Reinvestigation of the ultrastructure of spermiogenesis and the spermatozoon of Hymenolepis nana (Cestoda, Cyclophyllidea), parasite of the small intestine of Rattus rattus.

Spermiogenesis in Hymenolepsis nana begins with the formation of a differentiation zone. This is limited at the front by arched membranes, is surrounded by cortical microtubules associated with 12 crested-like bodies, and contains a single centriole made up of doublets. The distal centriole gives rise to a flagellum that grows at the same pace as the cortical microtubules. Migration of the nucleus takes place after the formation of the flagellum. It is followed by the separation of the old spermatid from the residual cytoplasm. The mature H. nana spermatozoon is filiform and lacks mitochondria. The axoneme, of the 9 + "1" pattern of the Platyhelminthes, does not reach the extremities of the spermatozoon. The nucleus is electron dense and is in close contact with the axoneme around which it coils in a spiral making an angle of 10 degrees to 15 degrees with the spermatozoon axis. The cortical microtubules follow a 10 degrees to 15 degrees helicoidal path along almost their whole length, except at their posterior extremity, where they are parallel to the spermatozoon axis. H. nana is distinguished by the early development of 12 crested-like bodies of different lengths and by the existence of a single centriole in the differentiation zone. Such a high number of crested-like bodies had never previously been reported in a cestode.

Animals↗
PubMed1992

Synthesis and ACE inhibitory activity of the stereoisomers of perindopril (S 9490) and perindoprilate (S 9780).

Perindopril, a powerful ACE inhibitor contains 5 chiral carbons, thus there is the possibility of 2(5) = 32 stereoisomers for the general structure 1. These 32 stereoisomers were synthesized by cross-coupling the 8 stereoisomers of perhydroindole 2-carboxylic acid benzylester with the 4 stereoisomers of 2-(1-carbethoxybutylamino) propionic acid 4, then hydrogenating the resulting benzylesters. Each stereoisomer of perindopril furnished by saponification the corresponding diacid stereoisomer 2 of perindoprilate which is the active form of perindopril. For each of the 32 stereoisomers 2 the in vitro ACE inhibitory potency (IC50) was determined. Four of them, including perindoprilate, had activities in the nanomolar range, and four more were ca. 10 x less active. The four acid esters 1 corresponding respectively to the four most active diacids 2 in vitro were studied (1 mg/kg via the oral route) for their in vivo activity in dogs. It could be concluded that p.o. absorption of the active acid esters 1 and their activation to the active diacid 2 depended only on the chiralities of the two ring junction carbons of the perhydroindole ring.

Administration, Oral↗
PubMed1992

Comparative ultrastructural study of the cuticle of larvae and adults of Centrorhynchus milvus Ward, 1956 (Acanthocephala, Centrorhynchidae).

The cuticle of Centrorhynchus milvus acanthella and cystacanth larvae, obtained from the terrestrial crustacean Porcellionides pruinosus, is roughly 0.2 micron thick. The cuticle of juveniles encysted in toads, paratenic hosts, measures up to 0.5 micron whereas that of adults may exceed 2 microns in thickness. In all cases it is perforated by numerous pores that communicate with the hypoderm. During larval development, the numerous endocytotic vacuoles observed in acanthella 3, 4, and 5 and cystacanths became elongated canals in juveniles and adults. There is no significant ultrastructural modification in the cuticle. In the larvae, on the other hand, there was progressive thickening of the cyst wall.

Acanthocephala↗
PubMed1991

Evidence for nucleating microtubules in microtubular associations and for an opening polarity under colchicine action.

Bundles of microtubular structures appear in the cytoplasm of germinal cells of the African frog Dicroglossus occipitalis. They are made of several associated microtubules. Every bundle contains one normal singlet and numerous arch-shaped microtubular structures growing in all directions from the singlet wall. The walls of these microtubules are shown to contain 10 to 13 protofilaments. Attempts made with colchicine point out their susceptibility to this antimitotic drug. The formation and opening of these microtubular structures give evidence of complex organization.

Animals↗
PubMed1991

Demonstration of the orientation of the Cestodes spermatozoon illustrated by the ultrastructural study of spermiogenesis and the spermatozoon of a Cyclophyllidea: Thysaniezia ovilla, Rivolta, 1874.

Spermiogenesis in Thysaniezia ovilla begins with the appearance of a differentiation zone equipped with peripheral microtubules, surrounded by arched membranes and containing two parallel centrioles surrounded by electron dense granular material. One of the centrioles aborts, the other gives rise to a flagellum which quickly grows in the cytoplasmic extension in which the nucleus migrates and protein granules form. During the nuclear migration crested-like bodies appear among the peripheral microtubules in the differentiation zone. The Th. ovilla spermatozoon is filiform. One of its extremities, which we show to be anterior, exhibits two helicoidal crested-like bodies, surrounded by electron dense material resembling an acrosome. Cortical microtubules run along almost the whole length of the spermatozoon. The cytoplasm has no mitochondria and contains protein granules. The axoneme is of the 9 + '1' pattern. It stops before reaching the posterior extremity of the gamete. The nucleus is wrapped round the axoneme, in the middle region of the spermatozoon. It generally stops before reaching the posterior extremity of the flagellum. This study has enabled us to describe precisely the orientation of the spermatozoon of cestodes in general.

Animals↗
PubMed1990

Interspecies comparison of the metabolic pathways of perindopril, a new angiotensin-converting enzyme (ACE) inhibitor.

1. The metabolism of perindopril (non-thiol angiotensin-converting enzyme inhibitor) was studied in rat, dog and monkey after single oral and i.v. administration of 14C-perindopril, and in man after a single oral dose. 2. Six biotransformation products of perindopril from urine, faecal and plasma samples (bile only for rats) were identified. 3. The main route of biotransformation in all species is the hydrolysis of the carboxylic ethyl ester side-chain, with the formation of perindoprilate, the active metabolite. 4. A minor route of biotransformation led to the acyl glucuronides of perindopril and perindoprilate. 5. Internal dehydration of perindopril and perindoprilate into cyclic lactam structures occurs. This route of metabolism is of minor importance except in humans.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1988

Analysis of almitrine and its metabolites in plasma using on-line fast atom bombardment liquid chromatography/mass spectrometry.

To validate a recently developed liquid chromatography/ultraviolet (LC/UV) method in a pharmacokinetic study of Vectarion (almitrine) where the unchanged drug, its five metabolites and an internal standard are analysed, on-line fast atom bombardment liquid chromatography/mass spectrometry (FAB LC/MS) with a moving belt interface has been used. Since the liquid chromatographic conditions required the use of perchloric acid FAB was chosen as ionization mode for the involatile perchlorates formed in the liquid chromatographic process. The use of FAB LC/MS allows the detection of the protonated molecular ions of all the components in the mixture. Furthermore, all the compounds show an intense peak at m/z 203, presenting a liquid chromatographic profile which is very similar to the profile obtained with UV detection.

Almitrine↗
PubMed1988

Assessment of global function: The Reintegration to Normal Living Index.

This paper reports the development of an instrument, the Reintegration to Normal Living (RNL) Index, to assess global function status. Information to determine the components of the index was systematically collected through interviews with professionals, patients, and their significant others, promoting content validity. Psychometric properties of the index were assessed using three samples of patients with varied diagnoses from several settings. The index demonstrates high internal consistency and adequate interrater reliability (patient and significant other). It is responsive to changes in the clinical status of patients, particularly when the subscales of Daily Living and Perceptions of Self are considered. In terms of criterion validity, the index is somewhat related to work status and disease status. It also demonstrates construct validity, both convergent and discriminant, when assessed against a quality of life index and an index of psychologic well-being. The RNL index appears to assess global function and measures both the patient's perceptions of their own capabilities and objective indicators of physical, social, and psychologic performance.

Activities of Daily Living↗
PubMed1985

Rapid enzyme immunoassay for quantification of C-reactive protein (CRP).

A simple, rapid enzyme immunoassay (EMIT CRP assay) for C-reactive protein (CRP) was assessed using human acute phase sera and purified human CRP. The calibration curve was established from 10 micrograms/mL to 150 micrograms/mL. The precision evaluations of the assay, carried out under optimal conditions of the test, (CRP levels: 20-100 micrograms/mL) showed coefficients of variation less than 7%, both for within-run and day-to-day precision. The limit of sensitivity was 10 micrograms/mL. The coefficients of correlation with radial immunodiffusion and immunonephelometry were respectively 0.988 and 0.956. The dilution assay showed a linear response. No significant changes in the CRP level were observed after sample storage either at 4 degrees C or -20 degrees C for 3 to 10 days, or after removing lipoproteins from sera. The EMIT CRP assay is characterized by its short assay time, its excellent precision, and its sensitivity is sufficient to detect an ongoing inflammatory process.

C-Reactive Protein↗
PubMed1980

[Rhodamine B: a tracer of follicular keratinization (author's transl)].

The mixture at equal volumes of a 0.1 p. 100 solution of rhodamine B in distilled water and of a 0.25 p. 100 solution of toluidine blue in Walpole's pH 4.4 buffer dyes each pilar sheath differently. At the level of the medulla, the granules fix rhodamine B, so do the cortical cells at the level of the keratogenic zone. Once they are keratinized, however, cortical cells remain colorless. Concerning the cells of the inner root sheath, on the other hand, their trichohyaline granules are dyed by rhodamine B, whereas the keratinized cells turn dark blue under the effect of toluidine blue. The trichilemmal keratin both of the isthmus of the anagen hair and of the follicular sac becomes light red. This technique, which can be easily applied to the trichogram, allows us to identify more or less mature pilar anlages in in adnexal tumors, to differentiate keratinizing cysts and to trace various pathological keratins. Thanks to a chemical study, it was shown that the mixture rhodamine B-toluidine blue is only a mechanical mixture which works through its acide-bases properties.

Basal Cell Carcinoma↗