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C Serres

Publications and source records attributed to C Serres.

14 recordsLinked to original sources
PubMed1991

Decrease of internal free calcium and human sperm movement.

In order to elucidate the effects of calcium on the movement of human spermatozoa, studies were conducted using motile cells selected by swim-up migration at 37 degrees C in 5% CO2 in air in a synthetic BWW medium containing 1.7 x 10(-3) M CaCl2 or BWW without added calcium (BWW-Ca). Preliminary experiments have confirmed that the addition of EGTA (5 x 10(-3); 10(-2) M) to BWW medium decreased the intracellular calcium concentration ((Ca++)i) of spermatozoa, as measured in cells loaded with a fluorescent Ca++ indicator, Quin-2. Concomitant measurements of (Ca++)i and sperm movement (analysed by videomicrography at 200 f/s at room temperature) were carried out on Quin-2 loaded cells incubated in BWW-Ca medium plus EGTA (10(-5) M; 10(-4) M; 10(-3) M). Under these conditions a decrease in (Ca++)i was observed and associated with a decrease in mean amplitude of lateral head displacement (ALH). Analysis using an automatic analyser (Hamilton Thorn at 37 degrees C) confirmed these results: the percentage of spermatozoa swimming with ALH greater than or equal to 6 microns is decreased when the external free calcium in BWW-Ca is decreased by the addition of 10(-5) M, 10(-4) M, or 10(-3) M EGTA. Flagellar analysis of the sperm population characterized by ALH greater than or equal to 6 microns showed a large proximal curvature of the tail associated with a low propagation wave velocity and a low beat frequency as compared to the spermatozoa with ALH less than 6 microns with similar progressive velocities. These characteristics result in a high flagellar beat efficiency (in terms of head displacement per beat). The disappearance of this pattern of movement when intracellular calcium is lowered indicates that calcium plays a complex role in the relationship between curvature and wave propagation. The ability of spermatozoa to modulate their movement in response to an alteration in the intracellular calcium level confirms the role of calcium in controlling flagellar movement in intact cells.

Aminoquinolines↗
PubMed1991

Comparative kinetics of short and long sperm in sperm dimorphic Drosophila species.

All species of the Drosophila obscura group exhibit within-ejaculate sperm length dimorphism. The present work is a contribution to the understanding of sperm competition through a comparative study of sperm kinetic parameters in four of these species. Videomicrographic observations at 200 frames per second of sperm from males and females, out of the storage organ, prior or after storage were made. Drosophila sperm display both major and minor waves. The former is analysed by measuring coiling diameter (micron) and the latter by recording both beat frequency (s-1) and wave propagation velocity (micron.s-1). Results show that the 'behaviour' of short and long spermatozoa noticeably differ: short sperm kinetics remains unaltered after storage while both major and minor waves of long spermatozoa are markedly modified. Thus, evidence is provided here of a sort of "differential activation" which is assumed to result in different survival abilities of short and long sperm within the storage organ of females.

Animals↗
PubMed1991

Metabolic transformation of intracraneally injected [1-14C]linoleic and [1-14C]alpha-linolenic acids in malnourished developing rats.

The effect of a low protein diet during pregnancy and lactation on the fatty acid composition of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from brains of ten-day-old rats was studied. The results indicated that partial deprivation of protein during early development was associated with an increase in the fatty acids of the n-9 family in PC. The fatty acids of the linoleic acid series decreased in PE but were not modified in PC. These minor changes did not affect the double bond index values either in PC or in PE. The effect of protein depletion on the in vivo metabolic transformation of intracraneally injected [1-14C]linoleic and [1-14C]alpha-linolenic acids was also studied. The percentage distribution of the labeled precursors and their derivatives among PC and PE differed from that of mass distribution. These results indicate that the direct uptake of polyunsaturated fatty acids from the blood and/or the low turnover rate of these acids incorporated into PC and PE might be involved in maintaining the fatty acid pattern of these brain lipids.

Aging↗
PubMed1990

Motion of individual human spermatozoa, both normal and lacking the outer dynein arms, during a continuous temperature rise.

The effect of increasing temperature from 22-25 degrees C to 37 degrees C on various motion characteristics of individual normal human spermatozoa and spermatozoa lacking the outer dynein arms (LODA) was studied by using a new automatic microscopic tracking method. It was found that: 1) The curvilinear velocity (Vc, measured between 1-3 sec) of both normal and LODA spermatozoa, fluctuated more or less intensely between spermatozoa; this fluctuation was not thermodependent. 2) The average Vc in the two groups of spermatozoa increased with the rise in temperature at a similar rate (1 micron/sec/degrees C), but LODA spermatozoa had an initial Vc lower than that of normal spermatozoa (12.5 +/- 5.3 microns/sec and 34.2 +/- 8.2 microns/sec, respectively). 3) The profile of the Vc increase associated with the temperature rise was different for the two groups of spermatozoa: for LODA spermatozoa it was linear between 25-37 degrees C, whereas for normal spermatozoa a plateau was reached at about 31 degrees C. 4) Various patterns of trajectory were found for both normal and LODA spermatozoa; these patterns were unrelated to temperature. However, LODA spermatozoa had more linear trajectories than normal spermatozoa. 5) Plots derived from reaction rate theory showed that the activation enthalpy, delta H was a function of the increase of Vc for both normal and LODA spermatozoa, but that delta H was higher for LODA spermatozoa.

Adenosine Triphosphatases↗
PubMed1990

A new automated method of image analysis: comparison of ciliary and flagellar beats.

A new automated method of image analysis of sperm flagellar (human) and cilia (Dunaliella) bends is developed. This method permits an automatic determination of the line characterizing the flagellum. Two dynamic parameters are measured: the wave propagation velocity and the wave curvature radius. The data reveal similar patterns in the propagation of the principal and reverse waves between flagelated and ciliated cells. Conversely, differences are seen in principal wave curvature due perhaps to the presence of periaxonemal structures in the flagellum, absent in cilium. The identical patterns of reverse wave curvaturei in both systems may be linked to axonemal limitations.

Cilia↗
PubMed1988

Influence of image sampling frequency on the perceived movement characteristics of progressively motile human spermatozoa.

Tracks of 30 progressively motile washed human spermatozoa were plotted manually from 200-Hz frame rate video recordings. Tracks at 100, 66.7, 50, 40, 33.3, 25, 20, 10, and 5 Hz were then constructed using every 2nd, 3rd, 4th, 5th, 6th, 8th, 10th, 20th, or 40th point. The 200-Hz tracks were analyzed by traditional manual methods, and all ten sets of tracks analyzed using a computer-assisted method ("Videomot," developed originally to analyze 30-Hz tracks) to eliminate observer bias. Progression velocity (VSL) remained constant under all analysis conditions. Average path velocity (VAP) also remained essentially constant, although Videomot was less reliable at high frame rates due to problems in determining the average path. Curvilinear velocity (VCL) was very frame rate dependent (the 25-Hz mean value was only 56.5% of that at 200 Hz), and Videomot was more accurate than manual analysis at 200 Hz. Values of the amplitude of lateral head displacement (ALH) were acceptable at most frame rates. At less than 66.7 Hz the inclusion of spurious curvilinear track deviations caused lower mean ALH values, and at 5 Hz ALH could not be measured since the track was essentially the average path. Beat/cross frequency (BCF) was also frame rate dependent; at high rates there was the same problem as with ALH measurements, while at less than or equal to 25 Hz the maximum BCF was restricted by the frame rate. We conclude that human sperm movement characteristics can be measured at frame rates ca. 30 Hz but only if the constraints affecting VCL and BCF values are understood and accepted. Finally, less than 10 Hz can only give values for VSL and, perhaps, VAP.

Humans↗
PubMed1986

Abnormal distribution of the periaxonemal structures in a human sperm flagellar dyskinesia.

The spermatozoa from four infertile patients showing a flagellar dyskinesia due to abnormal flagellar wave development have been studied by light and transmission electron microscopy (TEM) for flagellar morphology. No axonemal anomalies were found but modification of the periaxonemal structures was observed. The results of a stereological analysis revealed abnormal extension of the individual dense fibres along the axoneme in the four cases as compared with a control group. The order of termination of those structures was therefore altered. However, the overall fibre extension was the same in both groups (ie, 60% of the principal piece). The number and the location of the longitudinal columns were also modified, the predominant anomaly being the presence of a single column. The possible influence of those structural anomalies on the pattern of sperm movement is discussed. Our observations seem to agree with a previous hypothesis of the literature, that the dense fibres might play a role in flagellar flexibility. More particularly, we suggest that the abnormal extension of dense fibres No. 2, 3, and 4 and the symmetric distribution of the dense fibres on both sides of the plane of beating may alter the flagellar curvature amplitude and the cell rotation frequency.

Actin Cytoskeleton↗
PubMed1986

Sperm factors related to failure of human in-vitro fertilization.

Two groups of men were retrospectively selected according to their observed success in in-vitro fertilization. Seminal and post-migration sperm samples from a low fertilization rate group (less than or equal to 33% cleaved embryos) have been compared to results obtained from a high fertilization rate group (greater than or equal to 66%). It was found that a low mean value of the amplitude of lateral sperm head displacement and an increased percentage of abnormal acrosomes were related to in-vitro fertilization failure. None of the individual sperm factors studied was found to determine in-vitro fertilization success with certainty; only when they were considered in combination was it possible to predict the likelihood of successful in-vitro fertilization of human oocytes.

Acrosome↗
PubMed1985

Aberrant distribution of the peri-axonemal structures in the human spermatozoon: possible role of the axoneme in the spatial organization of the flagellar components.

A quantitative ultrastructural study combined with stereology was performed on semen samples from four men selected for apparently isolated anomalies of the peri-axonemal structures. Comparison of the results with those of a control group revealed a decrease: in the mean length of the principal piece; in the mean length of the 9 dense fibres and in the difference in length between the 9 dense fibres, all the fibres being approximately as long as the medium length fibres of the normal spermatozoon. In addition, longitudinal columns were single and/or in abnormal position. However, the extent of the dense fibres (along 60% of the principal piece) and their proportion within the flagellum (35.1% of the principal piece per fibre on average) were normal. Analysis of the results suggests that: A-tubules of the axonemal doublets are involved in the spatial arrangement of the peri-axonemal structures; axonemal microtubule-associated proteins (MAPs) may be responsible for this structural function; and three different types of longitudinal doublet differentiations may exist along the flagellar axoneme.

Humans↗
PubMed1975

Mechanism of action of progesterone on amphibian oocytes. A possible biological role for progesterone metabolism.

The ability of various steroids to induce maturation of Pleurodeles waltlii oocytes after incubation has been studied. Progesterone is metabolized during the course of maturation. All metabolites isolated are less efficient than progesterone for inducing germinal vesicle breakdown. Progesterone binding to the 'melanosome' fraction has been studied (KD = 4.5 X 10(-8) M at 4 degrees C). 20BETA-Hydroxy-pregn-4-en-3-one, the main progesterone metabolite isolated from the oocyte, also binds to the melanosome fraction, but with a lower affinity (KD = 1.6 X 10(-7) M at 4 degrees C). At high concentration 20beta-hydroxy-pregn-4-en-3-one induces maturation, but at low concentration it is a competitive inhibitor of progesterone. Progesterone metabolism in Pleurodeles oocytes can be interpreted as an inactivation process, and also as a mechanism for inhibitime progesterone action.

Animals↗
PubMedDate not supplied

Light scattering determination of various characteristic paramenters of spermatozoa motility in a serie of human sperm.

In this paper are presented the results obtained by the light scattering method of systematic study of different parameters characterizing spermatozoa motility in a series of human sperms, one hour and five hours after ejaculation. These results are relative to the concentration of spermatozoa, the percentage and the number of motile spermatozoa, the characteristic velocity and the velocity distributions. All these parameters are discussed one by one, the advantages (objectivity, small quantity of not diluted sperm, short time needed for measurements) and the limits of the light scattering method being pointed out. A comparison is made with results obtained by conventional methods. The fineness of this study shows that this method can be used with success in fundamental research as well as in a routine functional sperm study, allowing an objective and precise analysis of motility in a given population as a complex factor.

Cell Count↗