Pharmacokinetics of a single intravenous dose of marbofloxacin in adult donkeys

Six donkeys each received 2 mg/kg marbofloxacin as a 10 per cent aqueous solution administered intravenously. Principal pharmacokinetic parameters were determined and two efficacy indices were computed by using pharmacokinetic parameters and selected mic90 values of marbofloxacin against pathogenic equine strains to predict the efficacy of the drug at this dose. The pharmacokinetics of marbofloxacin in donkeys was characterised by a large mean volume of distribution at a steady state (1.15 [0.09] l/kg) and a long mean (sd) elimination half-life of 9.24 (1.96) hours. It was also characterised by a relatively slow total body clearance of 0.10 (0.02) l/kg/hour, slower than in horses. Using mic90 values of marbofloxacin against pathogenic equine strains with a daily dose of 2 mg/kg, appropriate values of efficacy indicators were obtained only for Enterobacteriaceae. Daily intravenous doses of 0.33, 2.62 and 20 mg/kg were calculated for evaluation in clinical trials of infections due to Enterobacteriaceae, Staphylococcus aureus and Streptococci, respectively.

Spatio-Developmental Distribution of the Prion-Like Protein Doppel in Mammalian Testis: A Comparative Analysis Focusing on Its Presence in the Acrosome of Spermatids1

The first prion-like protein doppel, officially designed as prion protein dublet, does not seem to be needed for prion disease progression, whereas its physiological function seems to be related to male fertility. Its expression is primarily detected in the male genital tract, and Prnd-inactivated male mice are sterile. We investigated the location of Doppel in the testis of various species of mammal to determine its physiological function. Doppel is expressed early during ontogenesis, and is found in both germ cells and Sertoli cells in mice, rats, boars, and humans. Doppel is permanently expressed in the Sertoli cells but at different levels according to species. Its expression in testicular germ cells was primarily detected in spermatids, with a transient presence in the acrosome. These data suggest that Doppel may play a physiological role in acrosome biogenesis and may be of use in studies of patients suffering from idiopathic infertility.

Progesterone induces hyperpolarization after a transient depolarization phase in human spermatozoa

Progesterone (P4) induces a membrane depolarization and various ion fluxes (chloride efflux, sodium and calcium influxes), which are required for the human sperm acrosome reaction (AR). By use of the potentiometric fluorescent dye DiSC3(5) and two different technical approaches, the present study aimed to quantify and further analyze P4-induced modifications in membrane potential in capacitated human spermatozoa. Spectrofluorimetric analysis revealed that the mean resting membrane potential of sperm was -58 +/- 2 mV (n = 12). When 10 microM P4 was added, the sperm membrane depolarized by approximately +15 mV, partly driven by a Cl- efflux. It subsequently repolarized to reach a significant lower potential than the initial resting potential in two thirds of the tested samples. The flow cytometry analysis showed a heterogeneous resting membrane potential and revealed that the depolarization-hyperpolarization events concerned only subpopulations, between 3% and 40% of the sperm cells according to the samples (n = 7). We hypothesize that P4 has a beneficial effect on the ability of zona pellucida to promote the AR in a sperm subpopulation by increasing the number of hyperpolarized cells presenting a membrane potential that is compatible with the opening of T-type calcium channels by subsequent zona pellucida-induced depolarization.

The acrosome reaction in human spermatozoa

During gamete interaction, sperm acrosome reaction (AR) induced by oocyte investment is a prerequisite event for the spermatozoa to pass through the zona pellucida (ZP), fuse with and penetrate the oocyte. Progesterone (P4), secreted by cumulus cells, is an important cofactor for the occurrence of this exocytosis event. The AR results from the fusion between outer acrosomal and plasma membranes, leading to inner acrosomal membrane exposure. Binding of agonists, P4 or ZP3 glycoprotein, to plasma membrane sperm receptors activates intraspermatic signals and enzymatic pathways involved in the AR. Among the proteins or glycoproteins described as potential sperm receptors for ZP, Gi/Go protein-coupled and tyrosine kinase receptors have been described. Sperm receptors for P4 are poorly characterized, except a putative GABA(A)-like receptor. ZP- and P4-promoted AR is mediated by an obligatory intracellular calcium increase, appearing first at the acrosome equatorial segment and spreading throughout the head. The plasma membrane channels involved in calcium entry are operated by a plasma membrane depolarization and protein phosphorylations mediated by protein kinase C and tyrosine kinase protein. Part of the calcium increase could also be due to intracellular store release through IP3- and nucleotide (cAMP)-gated channels. Besides adenylate cyclase and phospholipase C activations, intracellular calcium increase also stimulates PLA2 activity and actin depolymerization, leading to membrane fusion. Evaluation of AR by staining or fluorescent probes can be useful to predict fertilization success and to direct the therapeutic strategy in male infertility.

Induction of a sodium ion influx by progesterone in human spermatozoa

In human spermatozoa, progesterone (P(4)) induces a depolarization of the plasma membrane, a rapid calcium (Ca(2+)) influx, and a chloride efflux. The sodium ion (Na(+)) was partly responsible for the P(4)-induced depolarizing effect but was not required for calcium influx. We used fluorescent probes for spectrofluorometry to investigate whether P(4) induced a Na(+) influx and whether voltage-operated channels were involved in Na(+) and/or Ca(2+) entries. We found that 10 microM P(4) significantly increased intracellular Na(+) concentration from 17.8 +/- 2.0 mM to 27.2 +/- 1. 6 mM (P < 0.001). Prior incubation of spermatozoa with 10 microM flunarizine, a Na(+) and Ca(2+) voltage-dependent channel blocker, inhibited the sodium influx induced by 10 microM P(4) by 84.6 +/- 15.4%. The Ca(2+) influx induced by 10 microM P(4) was also significantly inhibited in a Na(+)-containing medium by 10 microM flunarizine or 10 microM pimozide (P < 0.01). In contrast, flunarizine had no inhibitory effect on the Ca(2+) influx induced by 10 microM P(4) in spermatozoa incubated in Na(+)-depleted medium. The P(4)-promoted acrosome reaction (AR) was significantly higher when spermatozoa were incubated in Na(+)-containing medium as compared to Na(+)-depleted medium. These data demonstrate that P(4) stimulates a Na(+) influx that could be involved in the AR completion. They also suggest that voltage-dependent Na(+) and Ca(2+) channels are implicated in P(4)-mediated signaling pathway in human spermatozoa.

[The movement of the human spermatozoon]

The human sperm flagellum is composed by an axoneme made up of peripheral doublets of longitudinal microtubules on which are fixed dynein arms and radial spokes. A mechanochemical cycle of attachment-detachment of dynein arms on the adjacent microtubules results in a sliding/bending or microtubules. This process repeated along the flagellum, induces the propagation of a wave. The progressive movement of ejaculated spermatozoa is modified during their transport through the feminal genital tract under the influence of microenvironmental factors. The microfibrillar structure of cervical mucus constraints the flagellar wave amplitude whereas the tubal or follicular secretions induce an hyperactivation of the movement characterized by a loss of progression and a high degree of flagellar curvature. Sperm movement modifications are depending on external regulatory factors among which some could be secreted by the oocyte or by the perioocyte layers to create a sperm chemotaxis which would optimize the gametic interaction. The external factors modulate sperm movement through their interaction with membrane "receptors" and intracellular messengers such as cyclic AMP, ATP, Calcium, pH. These latter control dynein-microtubules interaction through a phosphorylation-dephosphorylation process of axonemal proteins.

Use of the single-cell gel electrophoresis assay for the immunofluorescent detection of specific DNA damage

The single-cell gel electrophoresis assay or comet assay is now a widely used method to assess the level of DNA damage in irradiated or chemically modified cells. We propose an adaptation of the currently applied protocol, aimed at singling out a defined modified base, using an immunodetection approach. After the electrophoresis step, the DNA tail moment was measured using ethidium bromide. Simultaneously, cyclobutane pyrimidine dimers (CPDs), the targeted lesions, were revealed by an indirect immunofluorescence detection using a specific monoclonal antibody. The assay was validated on human fibroblasts exposed to UVB light. The dose-response curves were established, showing a linear increase of the antibody response with the dose between 1000 and 10,000 J/m2. The detection limit of the method was 500 J/m2. Digestion of the CPDs, induced at 3000 J/m2, with T4 endonuclease V led to a marked decrease of the antibody response, confirming the specificity of the assay. A preliminary repair experiment is reported in which the tail moment of the comets together with the antibody response are measured, showing the disappearance of 80% of the antibody fixation sites within 48 h.

The reactivation of demembranated human spermatozoa lacking outer dynein arms is independent of pH

The effect of pH, Mg-ATP, and free calcium on activity of the inner dynein arm was investigated using demembranated human spermatozoa lacking the outer dynein arms (LODA). The results were compared with those obtained for demembranated-reactivated normal spermatozoa to evaluate the functional properties of the inner and outer dynein arms in axonemal motility. The reactivation of Triton X-100-demembranated LODA spermatozoa was analysed at various pHs and concentrations of Mg-ATP and calcium using video recordings. The percentage of reactivated LODA spermatozoa as a function of Mg-ATP concentration was not dependent on pH, whereas reactivation of normal human spermatozoa is pH dependent. This suggests that there may be a pH-dependent regulatory mechanism associated with the outer dynein arms. A delay in the principal bend propagation of normal and LODA reactivated cells was found at pH 7.1. This disappeared at pH 7.8 in normal but not in LODA populations. This suggests a role for outer dynein arms in the initiation of the propagation of flagellar bends at alkaline pH. The level of LODA and normal sperm reactivation both depended on the calcium concentration in the medium. At lower free calcium concentrations, the reactivation level and beat frequency of reactivated cells were higher. Our results suggest a functional difference between outer and inner dynein arms of human spermatozoa based on a differential pH sensitivity. Moreover, calcium seems to exert its regulatory action elsewhere than on the outer dynein arms.

RU486 inhibits penetration of human spermatozoa into zona-free hamster oocytes

Previous studies have shown that RU486 decreases the concentration of intracellular calcium ([Ca2+]i) in human spermatozoa in vitro and partially antagonizes the effect of progesterone on calcium influx and sperm acrosome reaction. The present study has examined the effect of RU486 on the penetration of human spermatozoa into zona-free hamster oocytes. RU486 (10 microM) decreased significantly the rate of penetration of zona-free hamster oocytes by human spermatozoa, and nearly abolished penetration when present in the medium at concentrations of 50 and 100 microM. RU486 must be present in the medium to exert its inhibitory effect. At the same concentration (10 microM) as RU486, progesterone was unable to reverse the inhibitory effect of RU486 on the penetration rate of human spermatozoa.

Protein-energy malnutrition during gestation and lactation in rats affects growth rate, brain development and essential fatty acid metabolism

The influence of feeding a low protein diet to rat dams during gestation and lactation on lipid metabolism in pups was studied. Wistar rats were fed 5, 10, 15 and 25% dietary protein during gestation and lactation. Pup growth was monitored until weaning, and brain weight, protein concentration, proteolipid concentration and total lipid phosphorus concentration of brain were analyzed. The levels of fatty acids in dam milk as well as in pup liver phospholipids and brain prosphatidylcholine and phosphatidylethanolamine were determined. The progressive deprivation of maternal dietary protein produced a reduction in the total saturated fatty acid concentration of dam milk and an increment in the concentration of nonmetabolized linoleic acid. Pup body and brain weights as well as proteolipid, protein and total lipid phosphorus concentrations in brain were reduced in proportion to the degree of dietary protein deficiency. The products:precursor ratio of (n-6) fatty acids in liver phospholipids revealed an impairment in the elongation-desaturation pathway due to maternal protein deficiency. Both (n-6) and (n-3) polyunsaturated fatty acids within brain phosphatidylethanolamine were decreased by reduced maternal dietary protein intake, whereas only the linoleic acid-derived products were similarly affected in the corresponding phosphatidylcholine fraction. These results demonstrate the widespread and profound deleterious effects of low protein levels of maternal diet on the growth rate, brain development and fatty acid metabolism in rat pups.

RU486 and calcium fluxes in human spermatozoa

RU486 decreases the intracellular free calcium concentration in human spermatozoa incubated in capacitation medium. We investigated the calcium fluxes that this progesterone antagonist acts on. We found that 10(-5) M RU486 slowed down the basal calcium influx while progesterone accelerated it. Moreover, in the same way as RU486 inhibits the calcium increase promoted by progesterone, it inhibited the calcium influx stimulated by 10(-6) M thapsigargin, an endoplasmic reticulum Ca(2+)-ATPase inhibitor. So we speculated that RU486 does not necessarily compete for the same binding sites as progesterone to exert its inhibitory action. In the absence of extracellular calcium, pretreatment by 10(-5) M RU486 decreased the peak of [Ca2+]i released by 5 microM ionomycin. This indicates that RU486 could also act at the membrane level of some intracellular organelles of calcium storage.

[Sperm motility and fertilization]

Sperm motility is a key function in the process of fertilization. Significant gaps in the knowledge of the mechanisms of control and modulation of sperm motility still remain. It is well known that the percentage of motile sperm is correlated with fertility in vivo but the recent development of assisted reproductive technologies and the extensive use of objective methods to assess sperm movement in vitro indicate that the quality of sperm movement is important too for fertilization. However, the exact pattern of motility characteristics to fulfill fertilization in vitro and in vivo are not clearly established essentially because of the lack of multiparametric and controlled studies in vitro and prospective studies in vivo. There is also presently no evidence for an improvement of fertility when using different pharmacological approaches to increase sperm motility in vitro. Therefore, further efforts are required to improve our basic knowledge of the relations between sperm motility and fertility with the aim to adapt and apply it to the problem of male infertility.

Progesterone and RU486: opposing effects on human sperm

Progesterone induced a rapid influx of calcium in capacitated human sperm, followed by a long-lasting, dose-dependent increase of intracellular free calcium. Thereafter, progesterone increased the fraction of hyperactivated sperm and the acrosome reaction. On the contrary, the progesterone antagonist RU486 (mifepristone) induced an immediate and transient, dose-dependent decrease of intracellular free calcium and a drop in the values of sperm movement parameters related to hyperactivation. Moreover, RU486 counteracted the effects of progesterone on calcium influx, lateral sperm head displacement, and the acrosome reaction. Therefore, RU486 effects were opposite to those of progesterone. The nature of the membrane receptor(s) involved is unknown. Several steroids bearing 11 beta-phenyl substitutions, with different pharmacological profiles, were also investigated. It was concluded that the steroid structure and chemical groups added to the 11 beta-phenyl influence effects on calcium influx.

[A new entity of sperm pathology: peri-axonemal flagellar dyskinesia]

The study of 17 infertile men has led to define a new entity of sperm pathology as part of the more general field of flagellar dyskinesias. Sperm parameters of the studied patients and a control series have been first estimated by routine analysis (concentration, motility, morphology). To precise their characteristics, kinetic and ultrastructural investigations, as the zona-free hamster oocyte penetration test, have been performed. Sperm parameters of the studied cases, as revealed by routine analysis, were close to the control group. However, a major kinetic anomaly was found which was characterized by an important decrease of the amplitude of lateral head displacement (1.6 microns vs 5.3 microns, p < 0.001), although the progressive velocity was only slightly impaired (20.3 microns vs 24.9 microns, p < 0.05). Electron microscopy revealed anomalies limited to the peri-axonemal structures such as the outer dense fibers and the fibrous sheath. Rates of sperm-oocyte attachment were normal but rates of oocyte penetration were low (27.7% of decondensed sperm heads vs 85.6%, p < 0.001). Attempts to assisted fertilization with the studied patients (51 cycles of insemination, 8 cycles of in vitro fertilization) were unsuccessful. All these data suggest that the infertility can be attributed to the movement disturbances which should impair sperm propulsion throughout the cervical mucus and the zona pellucida.

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.

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.

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.

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.

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.

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.

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.

Sliding spermatozoa: a dyskinesia responsible for human infertility?

Microcinematographic analysis at 50 frames/second of motile spermatozoa from four sterile men, which were permanently unable to penetrate the cervical mucus or migrate through it was performed at ambient temperature. In all cases, we found the same abnormal pattern of movement, characterized by a very small amplitude of the periodic lateral displacement of the head and abnormal displacement of the wave along the flagellum. The results assessed the importance of normal sperm flagellar dynamics for fertility.

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.

Ultrastructural morphometry of the human sperm flagellum with a stereological analysis of the lengths of the dense fibres

The dimensions of the various regions of the flagellum and the length of each of the dense fibres has been determined by transmission electron microscopy of a large number of spermatozoa from ten men. The overall mean length of the flagellum was 60.5 micron, and its diameter diminished from 0.88 micron in the midpiece to 0.17 micron at the terminal filament. The midpiece and terminal filament as measured in longitudinal sections had variable lengths among spermatozoa (3.4 +/- 0.5 (S.D.) micron and 3.1 +/- 1.0 micron respectively). Stereological analysis was used to estimate the length of the principal piece (53 micron) and the dense fibres. These latter fibres were of unequal length and extended along 60% of the length of the principal piece. They fell into 3 groups with respect to their lengths: (i) fibres 3 and 8 were short (6 micron); (ii) fibres 4, 2 and 7 were of medium length (17, 18 and 21 micron respectively); and (iii) the longest fibres were 5, 6, 9 (31, 32 and 31 micron respectively) and fibre 1 which was a little longer (35 micron). Although there was variation in the length of the various fibres among spermatozoa, the order of their termination was relatively constant. The relationship between these quantitative data regarding the structural characteristics of the dense fibres and the shape of the flagellar wave is discussed.

Motility induction in hamster spermatozoa from caput epididymidis: effects of forward motility protein (FMP) and calmodulin inhibitor

The motility characteristics and the behaviour of caput spermatozoa were investigated. After dilution in B2 medium the majority of spermatozoa presented head-to-head agglutination and a twisted flagellum. Only a small population of these spermatozoa developed an anarchic motility pattern. The addition of crude bovine epididymal fluid forward motility protein (FMP) to the incubation medium suppressed flagellar angulation and agglutination. The addition of FMP to caffeine-activated spermatozoa induced a slow-swimming progressive movement in about 10% of the spermatozoa. In order to establish an hypothetical role of FMP in the regulation of calcium transport a calmodulin inhibitor, fluphenazin, was tested. When added to caffeine-activated spermatozoa at a rate of 10(-5) M, it induced about 15% of progressive spermatozoa with flagellar angulations. The trajectories of these spermatozoa were similar to those observed in samples of spermatozoa from the cauda epididymidis. It is concluded that during epididymal maturation a calcium-dependent mechanism might be involved in the transformation of an irregular movement into a progressive movement.

Effect of cross-fostering rats at birth on the normal supply of essential fatty acids during protein deficiency

The effect of protein deficiency on the activity of delta 6 desaturase in the mother during lactation was determined in the liver microsomal fraction and the fatty acid composition of milk lipids from the analyzed stomach contents. The activity of delta 6 desaturase was profoundly affected by protein deprivation during pregnancy and only reached the values of controls at about 10 days after parturition. This fact did not affect the fatty acid pattern of milk lipids and no significant differences in the contents of arachidonic acid were detected between the two groups. Nevertheless, protein deficiency apparently affected milk production. The effects of protein deprivation on the supply of polyenoic acids of cross-fostering rats at birth from protein-deficient to protein-sufficient diets and vice versa, and rats maintained during pregnancy and lactation on a low protein or control diet were examined. The fatty acid pattern of liver phospholipids of the four groups under study was determined and used as a biochemical parameter for evaluating polyenoic acid status. Protein deficiency markedly affected the fatty acid pattern of liver phospholipids. A significant decrease of both arachidonic and docosahexaenoic acids was observed. This fatty acid pattern was reversed when protein-deficient animals were placed on the control diet at birth. On the other hand, the fatty acid composition of controls was negatively affected by cross-fostering to a deficient diet. The findings from the present experiment provide evidence that the negative effect of protein malnutrition appears to be promoted at least in part, by the effect of protein depletion on the supply of polyenoic acids for normal development and metabolic adaptations.

Motility of human sperm without outer dynein arms

Motility of human sperm lacking outer dynein arms has been studied before and after selection of the motile fraction of spermatozoa by migration in a saline solution. The flagellar wave forms appeared normal in both the seminal plasma and saline but the rate of forward progression, the head velocity and the beat frequency were approximately half of those observed with normal sperm. However the spermatozoa were capable of moving forward and of migrating out of the seminal plasma.

Microcinematographic analysis of the motility of human spermatozoa incubated with caffeine

The effects of incubation with caffeine at final concentration of 0.5 and 5.0 mM for 30 min at ambient temperature were examined in three normal semen samples and three from asthenozoospermic men. A 50 frames/s microcinematographic analysis of the sperm motility was performed and two characteristic parameters of the trajectories, the progression velocity (Vp) and the amplitude of lateral head displacement (Ah), were measured. At the lower concentration (0.5 mM) no significant effects on the overall mean values (i.e. for all spermatozoa analyzed over the 6 samples) of Vp Ah were found. However, at 5.0 mM a significant reduction in the overall mean Vp was noted. The individual responses were variable between the 6 samples, but only in two of the asthenozoospermic samples and one normal ejaculate were the slow-swimming (less than 20 micrometer/s) spermatozoa accelerated by caffeine treatment. In other samples a reduction in the velocity of faster-swimming spermatozoa was observed. It would seem preferable to reserve caffeine treatment only for severe cases of asthenozoospermia where the distribution of sperm velocities of skewed towards low values.

The effects of centrifugation, various synthetic media and temperature on the motility and vitality of human spermatozoa

The influence of various technical procedures and diluent media upon human spermatozoa has been tested in vitro. The percentage and velocity of motile spermatozoa were measured objectively using laser Doppler velocimetry. Vitality was determined by fluorescent staining. Centrifugation of semen (diluted 1 : 1 with Tyrode) at forces of 500, 800, 1 800 and 2 500 X g resulted in almost complete sedimentation of the spermatozoa. After resuspension in Tyrode's, spermatozoal motility was not changed significantly. The percentages of motile spermatozoa (measured at 37 degrees C) in Tyrode's and B2 medium remained the same as those in seminal plasma throughout an 8-hr period of incubation at 20 degrees C, while those in Locke's and phosphate-buffered saline (PBS) were significantly lower. The instantaneous modal velocities (Vc) of spermatozoa (also measured at 37 degrees C) in Locks's, Tyrode's and B2 were all significantly increased as compared to those observed in seminal plasma during incubation at 20 degrees C; spermatozoa in PBS showed a significantly reduced velocity compared to seminal plasma, but the difference was not significant. However, the rates of decline of the percentage of motile spermatozoa and of their velocities were indistinguishable in all four synthetic media and in the seminal plasma. No significant change in vitality was observed in any medium during the 8-hr incubation period at 20 degrees C. When spermatozoa were incubated at 37 degrees C, rapid declines in both percentage motile and in velocity were observed with incubation periods lasting more than 4-h. Subjecting the spermatozoa to a temperature of 4 degrees C for 1-h did not significantly change either of the motility parameters (measured at 37 degrees C), although prolonged exposure to 4 degrees C did greatly reduce their motility and velocity percentages. The decline in vitality was slow and uniform during incubation at either 4, 20 or 37 degrees C over periods of up to 10-hr, the best survival apparently being obtained at 20 degrees C and the worst at 4 degrees C, although there were no significant temperature differences at any time.

[Motility of human spermatozoa (author's transl)]

Microcinematography has permitted the analysis of human sperm motility and the definition of various parameters which can be used to characterize such movements. The locomotor apparatus of the sperm flagellum consists of an axoneme to which has been added the dense fibers and the fibrous sheath. A dysfunction of flagellar locomotion may be caused by mutations resulting in various structural defects of which the most common affect the dynein arms.