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L J Zaneveld

Publications and source records attributed to L J Zaneveld.

At least 73 records · Page 4Linked to original sources
PubMed1986

Comparative activation studies with extracted and purified human proacrosin.

Proacrosin was purified from acid extracts of human spermatozoa by concanavalin A precipitation and Bio-Gel P-100 chromatography. Two molecular weight forms of proacrosin were obtained, a major one with a Mr of 70,000-71,000 and a minor one with a Mr of 47,000-53,000. In contrast to sperm extracts, the purified forms of proacrosin were free of acrosin inhibitor(s) and nonzymogen acrosin. By modulating pH, ionic strength and temperature, the activation of proacrosin in sperm extracts was compared to only the major form of purified proacrosin, since it seemed to be the source of the lower molecular weight form of proacrosin. In both preparations, proacrosin activation occurred maximally over a broad pH range (7.6-8.8 for purified proacrosin and 7.6-9.6 for extract). Additionally, an ionic strength of 0.1 and above caused a decrease in proacrosin activation in both preparations. Similarly, proacrosin was sensitive to short incubation periods at 45 degrees C and above which caused a decrease in the amount of proacrosin found in both preparations.

Acrosin↗
PubMed1986

Synthesis and inhibition of human acrosin and trypsin and acute toxicity of aryl 4-guanidinobenzoates.

The aryl 4-guanidinobenzoate, 4'-nitrophenyl 4-guanidinobenzoate (NPGB), is a potent inhibitor of sperm acrosin, an enzyme with an essential function in the fertilization process. NPGB prevents fertilization in a number of animal species and is a good lead compound for the development of contraceptive agents. In order to assess the efficacy of other aryl 4-guanidinobenzoates as acrosin inhibitors, 24 of these compounds were synthesized. Their inhibitory activity toward human acrosin was determined and compared with their activity toward human pancreatic trypsin in order to assess whether inhibitor sensitivity differed between these similar enzymes. Nine of the inhibitors were synthesized from phenols approved by the FDA for therapeutic use. The acute toxicity of these inhibitors in mice was determined and compared to that of nonoxynol-9, the most commonly used active ingredient in today's vaginal contraceptive preparations. All of the compounds proved to be potent inhibitors of human acrosin although 3 orders of magnitude difference were observed between the most and least effective inhibitors. Little specificity was present in regard to their inhibition of acrosin and trypsin. All the aryl 4-guanidinobenzoates synthesized from FDA-approved phenols were less toxic than nonoxynol-9, and it is concluded that these 4-guanidinobenzoates are of interest for further development and testing as nonhormonal contraceptive agents.

Acrosin↗
PubMed1986

Association of the in-vitro fertilizing capacity of human spermatozoa with sperm morphology as assessed by three classification systems.

Stained sperm morphology slides from an in-vitro fertilization programme were evaluated by the modified Williams system, the World Health Organization (WHO) system and morphometric size measurements (image analysis) to determine which system(s) were better predictors of fertility. Amorphous sperm head shape was the best predictor of fertility in both the modified Williams system and the WHO system, predicting the proper fertility status in 65% of the cases. Using only normal sperm in the statistical model, normal sperm became a correct predictor in 66% of the cases in the modified Williams system. Morphometric measurements were not useful in predicting the fertility status of these samples. These studies indicate that morphology can not be used as a sole predictor of fertilizing capacity of human spermatozoa.

Fertility↗
PubMed1986

Effect of hyaluronidase, beta-glucuronidase and beta-N-acetylglucosaminidase inhibitors on sperm penetration of the mouse oocyte.

The role of hyaluronidase, beta-glucuronidase and beta-N-acetylglucosaminidase in the penetration by mouse spermatozoa through the layers surrounding the oocyte was investigated by in vitro techniques. Myocrisin, fenoprofen, phosphorulated hesperidin and PS53 (a hydroquinone-sulfonic acid-formaldehyde polymer) inhibited fertilization when incubated with capacitated spermatozoa before the treated spermatozoa were mixed with intact oocytes but not when the inhibitor-treated, capacitated spermatozoa were added to oocytes free of follicle cells. The antifertility activity did not appear to be due to an effect on sperm motility or on the oocytes. These 4 compounds are known hyaluronidase inhibitors and, of the acrosomal enzymes tested, only share inhibition of hyaluronidase. Kinetic studies indicated that myocrisin is a reversible inhibitor of mouse sperm hyaluronidase whereas the other three are irreversible inhibitors. Adding saccharolactone, a beta-glucuronidase inhibitor, or N-acetylglucosaminolactone and N-acetylgalactosaminolactone, beta-N-acetylglucosaminidase inhibitors, to capacitated spermatozoa under the same conditions as the hyaluronidase inhibitors did not decrease fertilization. This was the case even though the beta-glucuronidase or beta-N-acetylglucosaminidase activities of the spermatozoa were completely inhibited, at least at the time that the inhibitor-treated, capacitated spermatozoa were mixed with the oocytes. The hyaluronidase activity of mouse spermatozoa remained unaltered during the incubation period required for capacitation; however, prolonged incubation caused a significant decrease in hyaluronidase. Untreated mouse spermatozoa caused hydrolysis of hyaluronic acid more effectively than did sperm extracts obtained by detergent extraction. These results are consistent with the theory of an essential role of hyaluronidase in mouse fertilization. At least in this species, the enzyme appears to be specifically involved in sperm penetration through the follicle cell layer. The data do not support an essential role for beta-glucuronidase and beta-N-acetylglucosaminidase in the penetration by mouse spermatozoa through the oocyte's investments. In contrast to some other species, sperm capacitation in mice does not result in a loss of hyaluronidase although part of the enzyme activity is lost on prolonged incubation. Mouse spermatozoa appear to be able to digest substrate (hyaluronic acid) even though hyaluronidase is not released.

Acetylglucosaminidase↗
PubMed1985

Diffusable proteins of the mucosa of the human cervix, uterus, and fallopian tubes: distribution and variations during the menstrual cycle.

The secretory proteins of the mucosa of the cervix, uterus, and fallopian tubes were investigated by measuring the proteins that were released by isolated mucosal areas. Initial screening disclosed that the immunoglobulins IgG and IgA were released in measurable quantities, but that IgM and the secretory (T) piece of IgA were either absent or present only in trace amounts. Relatively low levels of diffusable total complement activity and the C3 component of complement were present, whereas the C1q, C1r, and C4 components were either absent or present only in trace quantities. No neutral proteinase activity was present, but lysozyme, plasminogen activator, alpha 1-antitrypsin, and alpha 1x-antichymotrypsin could be found in reasonable amounts. The site of secretion, concentration, and cyclic variation of the proteins that diffused from the mucosal sites in measurable quantities were studied. The types and amounts of protein secreted by a particular site in the cervix, uterus, or fallopian tube varied from those of protein from other sites, even within the same organ. During the menstrual cycle, variations occurred in the amount of protein secreted by each mucosal site. However, whether an increase or a decrease in the release of a particular protein took place varied with each protein, even at the same site. The mucosal sites also differed from each other in their response to the phase of the menstrual cycle, that is, whether more or less protein was released, even sites within the same organ. The conclusion is that each organ and even different sites within an organ can respond independently from each other to changes in hormone levels, producing different types and amounts of secretory proteins. The amount of diffusable protein produced by an individual site during the menstrual cycle depends on the type of protein as well as the mucosal site.

Adult↗
PubMed1985

Demonstration of a functional blood-testis barrier to acetaldehyde. Evidence for lack of acetaldehyde effect on ethanol-induced depression of testosterone in vivo.

In vitro studies have shown that acetaldehyde is a more potent inhibitor of testicular steroidogenesis than ethanol. The present study examined the in vivo role of acetaldehyde in ethanol-induced reduction of testosterone by (1) determining the levels of acetaldehyde to which the testes were exposed subsequent to acute ethanol administration to mice; and (2) examining the effect of ethanol on testosterone in animals subsequent to drug pretreatment which decreased or increased ethanol-derived acetaldehyde. Ethanol-induced (3 g/kg) depression of testosterone was dependent upon gonadotropin stimulation. The increase in hCG-induced testosterone was suppressed (P less than 0.01) in ethanol- as compared to saline-treated animals [39.8 +/- 2.6 (S.E.M.) vs 28.1 +/- 2.3 ng/ml]. Pargyline (100 mg/kg) or cyanamide (8.4 mg/kg) increased (P less than 0.05) plasma and testicular acetaldehyde, while having no effect on the testosterone response to ethanol. Similarly, 4-methylpyrazole (25 mg/kg) reduced blood and testicular acetaldehyde to nondetectable levels, while having no effect on testosterone. Testicular acetaldehyde was lower (P less than 0.001) than plasma levels (14 +/- 2 vs 2.0 +/- 0.2 microM). This functional blood-testis barrier to acetaldehyde could be explained by testicular aldehyde dehydrogenases in the mitochondria (Km for acetaldehyde = 1.5 microM) and in the cytosol (Km = 123 microM) whose maximal activities totaled to more than 25-fold greater than that of testicular alcohol dehydrogenase (ADH). ADH was concentrated in the Leydig cells, while aldehyde dehydrogenase was evenly distributed in the testis. Ethanol prevented further hCG-induced rises in testosterone rather than inhibiting testosterone production to below pre-ethanol values. The above data argue against a significant role of acetaldehyde in the in vivo response of testosterone to ethanol. Ethanol appears to impair gonadotropin-testicular receptor interaction in vivo.

Acetaldehyde↗
PubMed1985

Orally administered ketoconazole rapidly appears in seminal plasma and suppresses sperm motility.

Ketoconazole has been shown to exert spermatostatic effects in vitro on ejaculated dog, monkey, and human spermatozoa. Oral administration of the compound to adult male beagle dogs (50-246 mg/kg) or rhesus monkeys (85-100 mg/kg) was associated with a decline in motility of sperm in ejaculates obtained after dosing. In dogs the decline in sperm motility was correlated with the presence of ketoconazole in the seminal plasma, although the measured concentrations of ketoconazole were no more than one tenth that needed for in vitro activity. The serum levels of testosterone in the dogs receiving oral ketoconazole were profoundly suppressed but the extreme rapidity of onset of the ex vivo effect on sperm motility, which was noted within 4 hours of dosing, makes it unlikely that testosterone withdrawal plays more than a minor role in the spermatostasis. The results in animals invite further pursuit of this novel, rapid onset, reversible, single dose use of spermatostatic agents for their potential as male contraceptives.

Administration, Oral↗
PubMed1985

Evidence for multiple catalytic sites of human acrosin from kinetic evaluation of fructose-induced acrosin inhibition.

Acrosin (acrosomal proteinase; EC 3.4.21.10) is a sperm-specific serine proteinase implicated in sperm penetration of the mammalian oocyte. Previously, we had shown that human acrosin, unlike human trypsin (EC 3.4.21.4), was inhibited by beta-D-fructose and related carbohydrates. The present study was undertaken to more fully elucidate the mechanism of action of fructose as an acrosin inhibitor, and to further differentiate the kinetic properties of acrosin from those of trypsin. Fructose produced a complex pattern of inhibition. At relatively low concentrations (10-60 mM), fructose acted as a competitive inhibitor with an apparent inhibition constant of 13 mM. In contrast, at high concentrations (80-320 mM), fructose behaved as a noncompetitive inhibitor, with an apparent inhibition constant of 205 mM. A Hill plot of enzyme activity as a function of fructose concentration suggested only a single binding site for fructose (slope = -0.90). The pattern of inhibition is not consistent with an enzyme containing only a single catalytic site, based either upon steady-state or rapid equilibrium assumptions; however, good agreement between observed and simulated data were obtained based upon the assumption of two catalytic sites with equal or similar binding and catalytic constants. The data suggested that fructose interacts with a single binding site (Ki = 8 mM) which alters both catalytic sites to produce an enzyme species having a higher apparent Michaelis constant and lower kcat as compared to the uninhibited enzyme. Fructose had no effect upon the rate of acrosin inactivation by either diisopropylfluorophosphate or tosyl-lysine-chloromethylketone, suggesting that neither substrate binding nor acylation were altered by this agent. The above data indicate substantial differences between the catalytic properties of human acrosin and those of trypsin.

Acrosin↗
PubMed1985

Vaginal contraceptive activity of aryl 4-guanidinobenzoates (acrosin inhibitors) in rabbits.

Nine aryl 4-guanidinobenzoates were synthesized as inhibitors of the sperm enzyme acrosin. These esters were prepared from 4-guanidinobenzoic acid and a number of phenols which had been approved by the FDA for clinical use. The vaginal contraceptive activity of the inhibitors was evaluated in the rabbit at nonspermicidal concentrations (0.1 mg/ml). All the inhibitors except the 2'-carboxamidophenyl and the 2'-isopropyl-5'-methylphenyl 4-guanidinobenzoates caused significant reductions in fertilization compared to the controls. Several of the aryl 4-guanidinobenzoates appeared to be particularly effective. Nonoxynol-9, under the same conditions but at 10- and 100-fold higher concentrations, also showed an antifertility effect. However, even at these increased dose levels, the contraceptive efficacy of nonoxynol-9 was no higher than that of most of the inhibitors and was less consistent than that of the most active aryl 4-guanidinobenzoates. The relatively high in vivo antifertility activity exhibited by several of the aryl 4-guanidinobenzoates encourages their further evaluation as vaginal contraceptive agents.

Acrosin↗
PubMed1985

Nonbeneficial effects of glycerol on the oocyte penetrating capacity of cryopreserved and incubated human spermatozoa.

The effect of cryopreservation on human spermatozoa in the presence or absence of glycerol was assessed by using sperm motility, functional integrity of sperm membrane, and denuded hamster oocyte penetration tests. Glycerol treated cryopreserved spermatozoa yielded a significantly higher (P less than 0.01) percentage of motile sperm and percentage of sperm with functionally intact membrane immediately after thawing than the spermatozoa not treated with glycerol but cryopreserved. However, no significant difference was observed between these cryopreserved spermatozoa (either treated or untreated with glycerol) on the percentage of motile sperm and the rate of oocyte penetration when the sperm were washed and incubated for 2 hr in a medium containing no glycerol. Thus, it appears glycerol may not be beneficial, since cryopreservation of spermatozoa either treated or untreated with glycerol essentially yields similar oocyte-penetrating capacity of sperm.

Female↗
PubMed1985

Inhibition of human sperm penetration into zona-free hamster oocytes by proteinase inhibitors.

The potential role of serine proteinase in the penetration of human spermatozoa into denuded (zona-free) hamster oocytes was investigated. Aryl 4-guanidinobenzoates (10(-4) to 10(-6) M) and 4-aminobenzamidines (10(-3) and 10(-4) M) decreased oocyte penetration when present throughout the assay system. More detailed studies with 8-quinolyl 4-guanidinobenzoate showed that this inhibitor also caused a large decrease in the penetration rate even when only present during the preincubation period of the spermatozoa to induce capacitation. Much smaller decreases were observed when this inhibitor was only present during sperm/egg incubation. By contrast, 4-aminobenzamidine caused a large decrease in the penetration rate when present during sperm/egg incubation but a much smaller one when present during the sperm's preincubation period. The primary action of the inhibitors was not due to a visible effect on sperm motility or forward progression, or to an effect on the oocyte, although treatment of oocytes with inhibitor caused a small decrease in penetration. Inhibition of sperm binding to the oolemma occurred also at times, but this was not directly correlated to the decrease in oocyte penetration. The results are consistent with the fact that a serine proteinase, presumably acrosin, is important for the capacitation, acrosome reaction, and/or oocyte penetration of human spermatozoa. The synthesized aryl 4-guanidinobenzoates are of interest as contraceptive agents because they possess phenols approved by the Food and Drug Administration (United States) for human use and should be relatively nontoxic.

Animals↗
PubMed1985

Treatment of cervical mucus with lectins: effect on sperm migration.

Treatment of midcycle human cervical mucus with the lectins Ulex europaeus agglutinin I (UE), wheat germ agglutinin (WGA), and peanut agglutinin (PA) did not alter the ability of spermatozoa to enter and migrate through the mucus. These lectins form glycoconjugates by binding to L-fucose (UE), N-acetylglucosamine and sialic acid (WGA), and D-galactose and D-galactose-(1-3)-D-N-acetylgalactosamine (PA), sugars that are present in the carbohydrate side chains of the mucus glycoproteins (mucins). Ricinus communis, with high affinity for D-galactose and N-acetylgalactosamine, did cause a significant decrease in sperm migration but only within the mucus (not at the sperm-mucus interface); this may have been because of an effect on sperm motility. These sugars are thought to be important for the secondary structure of the glycoproteins and for the cross linking between the mucins that produce the rheologic properties of cervical mucus. However, it appears that interference with the sugars by lectin binding does not significantly alter the ability of spermatozoa to migrate through cervical mucus.

Acetylglucosamine↗
PubMed1985

Vaginal contraceptive activity of hyaluronidase and cyclooxygenase (prostaglandin synthetase) inhibitors in the rabbit.

Seven inhibitors of the sperm enzyme hyaluronidase were tested at nonspermicidal concentrations for their vaginal contraceptive activity in rabbits. Five of these compounds are marketed antiinflammatory agents and the other two were synthesized. Most of the agents showed contraceptive activity. Of the antiinflammatory agents, phenylbutazone and oxyphenbutazone were particularly potent. Besides being hyaluronidase inhibitors, these compounds are also cyclooxygenase (prostaglandin synthetase) inhibitors; based on other in vitro data, their primary effect on spermatozoa is probably by the inhibition of that enzyme.

Animals↗
PubMed1985

Partial reversal of ethanol-induced male reproductive pathology following abstinence.

To date, no longitudinal studies have been carried out to determine the recovery of ethanol-related reproductive failure subsequent to moderate periods of abstinence. An animal model (C57B1 mouse) was utilized to examine the effectiveness of abstinence for reversal of ethanol-induced reproductive failure. After treatment with either a 5% (v/v) ethanol diet (10 weeks) or a 6% (v/v) ethanol diet (5 weeks), ethanol-treated animals and their pair-fed controls were electroejaculated and hemicastrated (right testis and accessory organs); their reproductive tracts and epididymal spermatozoa were examined. Ingestion of the 5% and 6% ethanol diets resulted in significantly (P less than 0.05) decreased weights of testes (24% and 28%, respectively) and seminal vesicles/prostate (20%, 6% diet only), increased frequencies of germ cell desquamation (480% and 400%), inactive seminiferous tubules (186% and 567%), sperm dysmorphology (31% and 119%) and inhibition of in vitro fertilization of mouse oocytes by epididymal spermatozoa (26% and 62%), as compared to their respective pair-fed control values. Also observed were significant decreases in epididymal sperm content (72%, 6% diet only), total motile spermatozoa (85%, 6% diet only) and seminal vesicles epithelial cell height (13% and 29%). No abnormal semen parameters were observed after treatment with the 5% ethanol diet; however, in animals treated with the 6% diet, significant decreases were noted in coagulum weight (50%), sperm count (85%) and acid phosphatase content (53%). Improvement in all parameters was observed in the contralateral half of the reproductive tract subsequent to 10 weeks abstinence. Only germ cell desquamation remained significantly elevated (100% as compared to control) in animals that ingested the 5% diet. In contrast, significant abnormalities persisting 10 weeks after treatment with the 6% ethanol diet included increased germ cell desquamation (200%), inactive seminiferous tubules (157%) and sperm dysmorphology (39%) and decreased forward progression (17%) of epididymal sperm, as compared to values. These findings are discussed in relation to the influence of alcohol consumption on male reproductive function in man.

Animals↗
PubMed1984

Lack of tubal occlusion by intrauterine quinacrine and tetracycline in the primate.

The effects of slow- and fast-releasing quinacrine pellets and tetracycline tablets on the genital tracts of 20 cynomolgus monkeys was evaluated. After surgical implantation of the pellets, the primates were observed for three months. No signs of toxic effects to the drugs were observed during the three-month period and on autopsy. Histopathological evaluation of the fallopian tubes, cervix, ovaries and uterus (except the endometrium) indicated they were all within normal limits. In no case were the uterotubal junctions obstructed. Endometrial changes were more frequent for quinacrine-treated monkeys. The results of the study point to the need for additional research regarding the optimal dose and duration of quinacrine administration.

Animals↗
PubMed1984

Comparison of human acrosin, a trypsin-like sperm proteinase, with human pancreatic trypsin: temperature stability and effect of cations.

Temperature and ion sensitivity of human acrosin (EC 3.4.21.10) was compared to that of human trypsin. With the exception of zinc, no ion tested had significant effects on either enzyme. Zinc behaved as a noncompetitive inhibitor of both enzymes, with inhibition constants of 1.8 and 1.7 mM for acrosin and trypsin respectively. Trypsin was inhibited by the chelators EDTA and EGTA, a specific effect reversed by either calcium or magnesium. EDTA inhibited acrosin in a nonspecific manner, while EGTA was without effect. Unlike acrosin from the other species, human acrosin was unaffected by calcium or the polyamines, spermine and spermidine. Acrosin was sensitive to inhibition by preincubation temperatures above 5 degrees C; trypsin, however, was stable to preincubation temperatures up to 60 degrees C. Hydrolysis of N-alpha-benzoyl-L-arginine ethyl ester was more efficiently catalyzed by trypsin (6800 cal/mol) than by acrosin (9511 cal/mol).

Acrosin↗
PubMed1984

Evaluation of the in vivo efficacy of a new vaginal contraceptive agent in stumptailed macaques.

The effect of precoital vaginal placement of three spermicidal formulations on postcoitally recovered vaginal and cervical spermatozoa was compared. Periovulatory stumptailed macaque monkeys were administered intravaginally 1 ml of Ramses Contraceptive Vaginal Jelly (C. Schmid Products Company, Little Fall, NJ), or a pluronic gel formulation containing 0, 0.1, or 1.0% of a new spermicidal compound, RS-37367. All spermicide-containing formulations reduced the motility of both vaginal and cervical sperm, compared with the gel containing no spermicide. The 1.0% RS-37367 formulation was particularly effective. No motile spermatozoa were recovered from either location, and only 0.5% of the numbers of cervical spermatozoa recovered in control animals were recoverable from this treatment group (P less than 0.0003). The formulation containing 0.1% RS-37367 appeared to be bioequivalent to the Ramses formulation containing 5% nonoxynol-9. These in vivo results support previous in vitro comparisons in which RS-37367 was estimated to be 50 times as potent a spermatostatic agent as nonoxynol-9.

Animals↗