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Biomedical subjects

D Montagnon

Publications and source records attributed to D Montagnon.

At least 19 recordsLinked to original sources
PubMed1996

First isolation of tandemly repeated DNA sequences in New World vultures and phylogenetic implications.

A highly repeated DNA sequence composed of closely related subunits that ranged from 171 to 176 base pairs has been cloned and characterized in the king vulture (Sarcoramphus papa). Related sequences were also isolated in the black vulture (Coragyps atratus). This new family of avian repetitive DNA elements is here termed the "HaeIII family." Genomic DNAs from a number of avian species were probed with one of the king vulture restriction fragments. In the cathartids, the hybridization patterns showed no individual or sexual variations. A strong HaeIII ladder was present in the two aforementioned species as well as in the Andean condor (Vultur gryphus), but in the black vulture the bands of the ladder alternated in intensity. Weaker hybridization signals were obtained in two ciconids, the jabiru stork (Jabiru mycteria) and the white stork (Ciconia ciconia). The HaeIII repeat was not detected in accipitrid birds of prey, a Polyborinae falconid, pelecanids, and psittacids.

Animals↗
PubMed1993

Comparison of highly repeated DNA sequences in some Lemuridae and taxonomic implications.

Highly repeated DNA sequences of Eulemur fulvus mayottensis, E. coronatus, Lemur catta, and Hapalemur griseus griseus have been identified and compared. Sequence analysis of highly repeated DNA fragments isolated from L. catta and Hapalemur showed a high percentage of similarity (nearly 95%), as did fragments isolated from the two very close Eulemur species, whereas comparison of the DNA fragments isolated from the two Eulemur species and the L. catta/Hapalemur group showed a very low percentage (approximately 40%) of identity, as might be expected for distant species. These results confirm our previous data, obtained by Southern blot hybridization techniques on the same species, and strongly support the existence of a common trunk between L. catta and Hapalemur, but different from the leading to the Eulemur species.

Animals↗
PubMed1993

Confirmation of the taxonomic position of Callimico goeldi (Primates, Platyrrhini) on the basis of its highly repeated DNA patterns.

The systematic position of Callimico goeldi has been analyzed by comparison of its highly repeated DNA fragments with those of three species of Callithricidae and two species of Cebidae. Our data, in agreement with those obtained by other authors by means of cytogenetic and molecular biology techniques, are in favour of the classification of C. goeldi in the family Callithricidae.

Animals↗
PubMed1992

[Electrophoretic study of the protein composition of human seminal vesicle secretion].

The SDS-PAGE and two-dimensional reductived electrophoretic study of the liquid aspirated from human seminal vesicles showed that this medium contains high molecular weight proteins (greater than 150 kDa). In addition to these high molecular weight proteins, native seminal vesicle secretion is characterised by the presence of a large 47.4 kDa protein band corresponding to seminogelin, described by Lilja. The high molecular weight proteins actually correspond to associations of three types of protein subunits with molecular weights of 75-76, 63-64 and 47-48 kDa, which represent the structural elements of the coagulum; one of these subunits consists of seminogelin. Seminal vesicle secretion contains very little or no proteolytic enzymes, so that its protein composition remains stable even after incubation for 24 hours.

Body Fluids↗
PubMed1990

Secretory proteins of human seminal vesicles and their relationship to lipids and sugars.

Proteins secreted by human seminal vesicles are strongly positively charged. Cellulose acetate electrophoresis show how the presence of two protein bands of vesicular origin (N3 and N4). When studied on SDS-PAGE there are three main bands of molecular weight 67, 45 and 40 kDa, respectively. These proteins may be separated by a chromatographic process using gel filtration on Sephadex G 25 M and ion exchange chromatography on CM and SP Sephadex C 50. Fructose, secreted by seminal vesicles, is excreted with specific proteins and these complexes take part to coagulum formation. During liquefaction glucose appears progressively and fructose is released from complexes with proteins. Interconversion processes that transform fructose into glucose, originate from prostatic secretion. In man, the liquefaction process seems to be not due to proteolysis, but by the way of other mechanisms that transform vesicular proteins of very high molecular weight into sub-units with lower molecular weights in the first minutes after ejaculation. In species other than man, i.e. lemurian, fructose takes part in the coagulation process with other components (albumin, ions, -SH groups). Cholesterol appears to be in relation with proteins which have high molecular weights. Half of phospholipid content of seminal plasma is probably free. Incubation of seminal plasma with spermatozoa show that these cells use triglycerides for their metabolism. The ratio between cholesterol and phospholipids is an important marker for the capacitation-decapacitation process.

Carbohydrates↗
PubMed1986

[Peroperative spinal cord ultrasonography in neurosurgery].

Intraoperative spinal sonography is a new method of investigation. We are reporting 14 observations. The results of these explorations permit to describe the normal spinal sonography and a spinal ultrasonic semeiology. We underline the advantage of this technic in the neurospinal surgery particularly to locate the tumors and to facilitate the removal.

Adolescent↗
PubMed1986

[Peroperative spinal cord echography].

Real time intraoperative ultrasonography is used since 1982 in spinal surgery. It gives numerous information, so that the neurosurgeon may adapt his technique to the obtained views. The authors describe this technique and give their experience based on 25 preliminary cases and on the literature. The normal echoanatomy of the spinal cord and the spinal canal is described as well as the echostructure of the different components observed in all cases. They give afterwards the different aspects of intramedullary tumours, extramedullary lesions (intra or extradurally), spinal traumas and syringomyelia.

Humans↗
PubMed1985

Soluble seminal fluid proteins from various animal species.

When soluble seminal proteins from different animal species are studied by cellulose acetate electrophoresis, important differences can be observed. These differences may be related to the type of coitus and the storage and migration of spermatozoa in the female genital tract. Seminal fluid can play a role in spermatozoal maturation by affecting the distribution of the surface charge of spermatozoal membranes.

Albumins↗
PubMed1984

Effects of prostatic secretion on reduced sugars in human seminal plasma.

Glucose and fructose levels were determined enzymatically in liquefied human seminal plasma (whole or collected in three fractions) and in preparations obtained by DEAE ion-exchange chromatography on whole seminal plasma. When these secretions or DEAE-extracted preparations were overloaded with fructose, the level of glucose increased. This increase is greater in fraction I of split ejaculates than in fractions II and III, and is greater in solutions containing elements of prostatic secretion obtained chromatographically than in whole seminal plasma. Using increasing quantities of fructose in the overloading test, glucose levels reached a maximum, suggesting that the process of conversion of fructose into glucose appears to be related to an enzymatic process. Other experiments suggest that the sperm-free fraction I of split ejaculates and compounds obtained from seminal plasma by ion-exchange chromatography contain enzymes of prostatic origin that are involved in the conversion of fructose to glucose.

Carbohydrate Metabolism↗
PubMed1983

[Relation between spermatozoids and reducing sugars (glucose and fructose) in human seminal fluid].

The prostatic fraction of seminal plasma contains components that are involved in the process of transforming fructose into glucose. If a positive correlation can be found between the slope of the decrease of fructose (estimated to be between 30 minutes and 5 hours) and the sperm count, with at the same time the maintenance of a relatively constant glucose level, then we have been able to demonstrate that glucose is more efficient than fructose to keep spermatozoa mobile. The enzyme process involved in transforming fructose into glucose may thus act to maintain definite glyspermia with a maximum value of 1.8 g/l. Aspermia in some circumstances then can be related to the absence or poor function of the transformation process and thus with the absence or decrease in prostatic secretion.

Fructose↗
PubMed1981

Pathological seminal plasma proteins by cellulose acetate electrophoresis.

Pathological seminal liquids were studied by using cellulose acetate electrophoresis as well as biochemical doses of proteins, acid phosphatases, reducing sugars, and zinc. It was also possible to show the frequent total absences of vesicular secretion, less frequent than prostatic secretion and less than the two at the same time. It was also shown that reductions were more frequent in prostatic secretion than in vesicular secretion. This method may also be a valuable assistance in the diagnosis of certain urogenital infections. The dissociation between prostatic secretions of acid phosphatases and zinc may lead to the diagnosis of the infection in the posterior or lateral lobes of the prostate.

Acid Phosphatase↗