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C Gagnon

Publications and source records attributed to C Gagnon.

At least 55 records · Page 3Linked to original sources
PubMed1997

Characterization of prostate-specific antigen proteolytic activity on its major physiological substrate, the sperm motility inhibitor precursor/semenogelin I.

The protease prostate-specific antigen (PSA) is a marker widely used clinically for monitoring prostatic malignancies. Under normal conditions, this enzyme is mainly involved in the post ejaculation degradation of the major human seminal protein, the seminal plasma motility inhibitor precursor/semenogelin I (SPMIP/SgI), which is the predominant protein component of human semen coagulum. PSA primary structure and activity on synthetic substrates predict a chymotrypsin-like activity whose specificity remains to be established. The present study was aimed at characterizing the proteolytic processing of the SPMIP/SgI by PSA. Purified SPMIP/SgI was incubated with PSA in the presence or absence of protease inhibitors. General serine protease inhibitors, heavy metal cations (Zn2+ and Hg2+), and the heavy metal chelator 1,10-phenanthroline partially or totally inhibited the proteolytic activity of PSA toward SPMIP/SgI. Under identical conditions, other proteins, such as bovine serum albumin, ovalbumin, and casein, were very poor substrates for PSA. Hydrolysis products were separated by reverse-phase high-performance liquid chromatography, assayed for sperm motility inhibitory activity, and analyzed by immunoblotting and mass spectrometry. The region responsible for the sperm motility inhibitory activity and containing an SPMI antiserum epitope was localized to the N-terminal portion of the molecule between residues 85 and 136. On the other hand, a monoclonal antibody against a seminal vesicle-specific antigen (MHS-5) recognized fragments derived from the central part of the SPMIP/SgI (residues 198-223). PSA hydrolysis occurred almost exclusively at either leucine or tyrosine residues, demonstrating directly for the first time a restricted chymotrypsin-like activity on a physiological substrate. The results suggest that PSA is the main enzyme responsible for the processing of SPMIP/SgI in human semen and that this protease manifests unusual specificity with respect to hydrolyzable substrates and sites of hydrolysis.

Amino Acid Sequence↗
PubMed1997

Regulation of protein-tyrosine phosphorylation and human sperm capacitation by reactive oxygen derivatives.

Spermatozoa undergoing capacitation, a necessary prerequisite event to successful fertilization that can be induced in vitro by reactive oxygen species (ROS), generate superoxide anion (O2.-). Because, in neutrophils, the generation of O2.- is associated with tyrosine phosphorylation of several proteins, the aim of the present study was to investigate the association between protein-tyrosine phosphorylation and ROS-induced human sperm capacitation. Human spermatozoa express two major phosphotyrosine-containing proteins of 105 and 81 kDa, the phosphotyrosine content of which is increased when spermatozoa are incubated under capacitating conditions. Superoxide dismutase and catalase abolish both sperm capacitation and tyrosine phosphorylation of p105 and p81, suggesting the involvement of O2.- and hydrogen peroxide in these two processes. Inhibitors of NADPH oxidase, the enzyme responsible for the neutrophil's respiratory burst, decrease both p105 and p81 tyrosine phosphorylation and sperm capacitation while hydrogen peroxide stimulates these two processes. Tyrosine phosphorylation of p105 and p81 occurs through a herbimycin A-sensitive tyrosine kinase, and sperm incubation with phosphotyrosine-protein phosphatase inhibitors results in an increase in phosphotyrosine content of these two proteins. Indirect immunocytochemical studies reveal phosphotyrosine-containing proteins mostly in the principal piece of the flagellum, in agreement with the localization of p105 and p81 in the human sperm fibrous sheath. Although tyrosine phosphorylation of p105 and p81 and sperm capacitation are related in a time-dependent fashion, some discrepancies are observed in the regulation of these two processes according to the redox status of the spermatozoa.

Enzyme Inhibitors↗
PubMed1997

Capacitation as a regulatory event that primes spermatozoa for the acrosome reaction and fertilization.

Capacitation is defined as the series of transformations that spermatozoa normally undergo during their migration through the female genital tract, in order to reach and bind to the zona pellucida, undergo the acrosome reaction, and fertilize the egg. During this process, extensive changes occur in all sperm compartments (head and flagellum; membrane, cytosol, cytoskeleton), factors originating from epididymal fluid and seminal plasma are lost or redistributed and membrane lipids and proteins are reorganized; ion fluxes induce biochemical modifications and controlled amounts of reactive oxygen species are generated; spermatozoa develop hyperactivated motility; and complex signal transduction mechanisms are initiated. The main purpose of capacitation is to ensure that spermatozoa reach the eggs at the appropriate time and in the appropriate state to fertilize these eggs, by finely-controlling the rate of the changes necessary to prime spermatozoa and by activating all the mechanisms needed for the subsequent acrosome reaction. The reversibility of some of the mechanisms leading to sperm capacitation may therefore be a very important aspect of the fine regulation and perfect timing of this process.

Acrosome↗
PubMed1997

Association of -158 (C-->T) (XmnI) DNA polymorphism in G gamma-globin promoter with delayed switchover from fetal to adult hemoglobin synthesis.

In this study, the effect of -158 (C-->T) (XmnI) polymorphism on the synthesis of fetal Hb and its G gamma component during the switchover from fetal to adult Hb was examined using cord blood samples from normal Caucasian term infants. The presence of -158(C-->T) mutation was determined by amplification of G gamma and A gamma-globin gene promoter fragments from the DNA isolated from cord blood samples, followed by XmnI restriction enzyme digestion. The syntheses of fetal and adult Hb in cord blood were measured by [3H]leucine incorporation in globin synthesis, separation of the globin polypeptides by HPLC, and scintillation counting of the fractions. The presence of -158(C-->T) substitution in the G gamma-globin promoter region was positively correlated with elevated synthesis of fetal Hb and its G gamma-globin component in term newborn infants and is associated with delayed switchover from fetal to adult Hb. In addition analysis of cord blood samples from 100 normal Caucasian French Canadian term infants revealed that the frequency of -158(C-->T) substitution in G gamma-promoter was 0.32.

Adult↗
PubMed1997

Motility of spermatozoa in hydrosalpingeal and follicular fluid of pigs.

Hydrosalpinges were created to collect adequate volumes of fluid during pre-, peri- and postovulatory intervals from the ampulla, ampullary-isthmic junction and the isthmic-utero-tubal junction of the oviducts from Large White gilts that had exhibited at least two natural oestrous cycles. The accumulated fluids, follicular fluid and Butschwiler's medium were compared for their effects on various parameters of boar sperm motility using the CellSoft, computer-assisted, digital image analysis system. Sperm velocity (micron s-1 +/- SEM) was significantly higher (P < 0.05) in follicular fluid (84 +/- 3; n = 5) than in fluids from the ampulla during peri- and early postovulatory intervals, and from the isthmic-utero-tubal junction during pre- and early postovulatory intervals. It was also higher (P < 0.05) than in the fluid from the ampullary-isthmic junction during pre- and early postovulatory intervals; however, sperm velocity in follicular fluid was not significantly different from that in the periovulatory fluid from the ampullary-isthmic junction. The mean lateral head displacement (ALHmean) of spermatozoa was significantly greater in follicular fluid (3.9 +/- 0.3 microns; n = 5) than in fluid from the ampulla during peri- and early postovulatory intervals and from the isthmic-utero-tubal junction during pre- and early postovulatory intervals, and was also higher (P < 0.05) than in fluid from the ampullary-isthmic junction during the preovulatory period, but was not different from the peri- and postovulatory ampullary-isthmic junction fluids. The proportion of spermatozoa exhibiting circular motion was significantly higher (P < 0.05) in the periovulatory fluid from the ampullary-isthmic junction (24 +/- 3%) compared with fluids obtained during preovulatory and early postovulatory periods. Follicular fluid had no effect on the proportion of spermatozoa exhibiting circular motion. The average radius of sperm movement in circular trajectories was higher in follicular fluid than in the periovulatory fluids from the ampulla and ampullary-isthmic junction (P < 0.05). In hydrosalpingeal fluids collected 2-5 days after ovulation, the average radius of movement was greater in the ampulla fluid and ampullary-isthmic junction fluid than in fluid from the isthmic-utero-tubal junction (P < 0.05). These results demonstrate that follicular fluid and oviductal fluids have considerable influences on boar sperm motility. Furthermore, the immediate effect of periovulatory ampullary-isthmic junction fluid in increasing the percentage of spermatozoa swimming in circles (hyperactivated) is relevant, since it is at this time and within this region that fertilization occurs.

Animals↗
PubMed1997

Reactive oxygen species and sperm physiology.

Although high concentrations of reactive oxygen species (ROS) cause sperm pathology (ATP depletion leading to insufficient axonemal phosphorylation, lipid peroxidation and loss of motility and viability), recent evidence demonstrates that low and controlled concentrations of these ROS play an important role in sperm physiology. Reactive oxygen species, such as the superoxide anion, hydrogen peroxide and nitric oxide, induce sperm hyperactivation, capacitation or the acrosome reaction in vitro. The ROS involved in these processes may vary depending on experimental conditions, but all the evidence converges to describe these events as 'oxidative' or 'redox regulated'. Human sperm capacitation and acrosome reaction are associated with extracellular production of a superoxide anion that is thought to originate from a membrane 'oxidase'. The enzymes responsible for tyrosine phosphorylation-dephosphorylation of sperm proteins are possible targets for ROS since mild oxidative conditions cause increases in protein tyrosine phosphorylation and acrosome reaction. The lipid peroxidation resulting from low concentrations of ROS promotes binding to the zona pellucida and may trigger the release of unesterified fatty acids from the sperm plasma membrane. The fine balance between ROS production and scavenging, as well as the right timing and site for ROS production are of paramount importance for acquisition of fertilizing ability.

Animals↗
PubMed1997

Morphological and biochemical changes following acute unilateral testicular torsion in prepubertal rats.

PURPOSE: The role played by reactive oxygen species in the effects of testicular torsion and torsion/detorsion on ipsilateral and contralateral testis was investigated. MATERIALS AND METHODS: Prepubertal rats were submitted to unilateral testicular torsion alone or followed by detorsion for up to 1 week. Morphology and biochemical parameters (thiobarbituric reactive substances, superoxide dismutase-like and catalase-like activities) were evaluated. RESULTS: Torsion (1 or 2 h) alone induced time-dependent morphological damages that worsened progressively after detorsion in ipsilateral testis but had no effect on contralateral testis. The levels of antioxidants against the superoxide anion and hydrogen peroxide decreased in ipsilateral but not in contralateral testis. However, the level of thiobarbituric reactive substances (an indicator of lipid perioxidation) decreased after testicular torsion or torsion/detorsion in both testes. CONCLUSION: These data emphasize that oxidative stress may play a role in testicular damage caused by torsion/detorsion and that biochemical indicators of oxidative stress are more sensitive than histological techniques in detecting modifications in the contralateral testis.

Aging↗
PubMed1996

Purification, cloning, and sequence analysis of a Mr = 30,000 protein from sea urchin axonemes that is important for sperm motility. Relationship of the protein to a dynein light chain.

We have generated a series of monoclonal antibodies against axonemal proteins from sea urchin spermatozoa in order to identify novel proteins involved in the regulation of flagellar motility. The monoclonal antibody D405-14 inhibited the motility of demembranated-reactivated sperm models at low concentrations and recognized a single polypeptide of 33 kDa (p33) on immunoblots of sea urchin axonemal proteins. Fractionation of the axonemes with high salt solutions, heat, and detergent resulted in the selective extraction of p33 into a 0.6 M NaCl-soluble and a 0.5% sodium lauryl sarcosinate (Sarkosyl)-soluble form. Both forms of p33 were purified to apparent homogeneity by immunoaffinity chromatography on monoclonal antibody D405-14-Sepharose. We have also isolated and sequenced a full-length cDNA clone encoding the 33-kDa protein. The sequence predicts a polypeptide of 260 amino acids having a mass of 29,730 Da and an isoelectric point of 9.3. Sequence comparison indicates that p33 is 66% identical (74% similar) to the p28 light chain of axonemal inner dynein arm of Chlamydomonas reinhardtii. Taken together, these results suggest that we have identified a p28 light chain homolog in sea urchin sperm axoneme and that this protein may play a dynamic role in flagellar motility.

Amino Acid Sequence↗
PubMed1996

Inhibition of flagellar beat frequency by a new anti-beta-tubulin antibody.

A panel of monoclonal antibodies (mAbs) has been generated against sea urchin sperm axonemes and selected for their ability to inhibit the motility of sea urchin sperm models. The mAb C9 recognized a 50 kDa protein on blots of sea urchin sperm axonemes. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that C9 recognized isoforms of beta-tubulin. Low concentrations of C9 (0.1-1.0 microgram/ml) blocked the motility of sea urchin sperm models by decreasing the sliding velocity and frequency of flagellar beating to less than 1 Hz and by modifying the shear angle along the axoneme, especially the distal end. Other antitubulin antibodies had little effect on motility at concentrations 100-fold higher than those effective for C9. The effects on motility were not restricted to flagella of sea urchin spermatozoa. Flagellar beating of the dinoflagellate Oxyrrhis marina was completely blocked by C9 in a manner reminiscent of that of sea urchin sperm flagella. The mAb also inhibited the motility of human spermatozoa and Chlamydomonas reinhardtii. Immunofluorescence techniques revealed that C9 stains the whole axoneme of sea urchin spermatozoa and O. marina flagella together with the cortical network of O. marina cell body. C9 is the first antitubulin antibody reported to interfere with flagellar beat frequency. The observation that this antibody arrests the motility of flagella from sea urchin sperm along with that of dinoflagellate, algae, and human sperm flagella suggests that the epitope recognized by C9 is conserved over a long period of evolution and plays an important role in sperm motility.

Animals↗
PubMed1996

Phosphorylation of Triton X-100 soluble and insoluble protein substrates in a demembranated/reactivated human sperm model.

Sperm motility is a process which involves a cascade of events mediated by cAMP and Ca2+, cAMP in the initiation of flagellar movement, and Ca2+ in the regulation of beat asymmetry, and it has been suggested that these two messengers act through phosphorylation/ dephosphorylation of axonemal proteins. Only a few studies on human sperm protein phosphorylation have been reported and no relation of this process with motility or other function has been established. In the present study, phosphorylation of human sperm proteins was performed using detergent-demembranated spermatozoa, in which motility is reactivated by the addition of ATP. This system allows direct accessibility of intracellular kinases to [32P] gamma ATP and allows some relation between protein phosphorylation and flagellar movements. After electrophoresis and autoradiography, numerous phosphoproteins were detected. Phosphorylation of 2 proteins (36 and 51 kDa) was stimulated by cAMP in a concentration-dependent manner, and this increase was prevented by inhibitors of cAMP-dependent protein kinase. In order to characterize phosphoproteins originating from the cytoskeleton or axoneme, detergent extracted spermatozoa were also subjected to phosphorylation. Three major phosphorylated proteins (14.8, 15.3, and 16.2 kDa) were detected, the first two expressing cAMP-dependency according to their cAMP concentration-dependent increase in phosphorylation and the reversal of this effect by inhibitors of cAMP-dependent protein kinase. Proteins phosphorylation during the reactivation of demembranated spermatozoa previously immobilized H2O2, xanthine + xanthine oxidase-generated reactive oxygen species, or the oxidative phosphorylation uncoupler rotenone, revealed increases in cAMP-independent phosphorylation of proteins of 16.2, 46, and 93 kDa. These results documenting human sperm phosphoproteins form a base for further studies on the role of protein phosphorylation in sperm functions.

Cyclic AMP-Dependent Protein Kinases↗
PubMed1996

Effect of catalase and thioredoxin addition to sperm incubation medium before in vitro fertilization on sperm capacity to support embryo development.

OBJECTIVE: To determine whether addition of catalase and thioredoxin to sperm incubation medium before IVF improves sperm potential to support embryo development. DESIGN: CD-1 mouse spermatozoa were preincubated without or with catalase or thioredoxin for 1 hour before IVF, and sperm motility parameters, fertilization rate, and embryo development were determined. SETTING: A conventional laboratory setting. INTERVENTION(S): Mice were superovulated with pregnant mare serum gonadotropin and hCG. Eggs in cumulus oophorus were collected and used for fertilization with epididymal spermatozoa. MAIN OUTCOME MEASURE(S): Sperm motility parameters, fertilization rate, and embryo development. RESULT(S): Sperm motility parameters and fertilization rates were not affected by catalase treatment. However, the rates of blastocyst and hatching blastocyst formation when catalase-treated (16 micrograms/mL) spermatozoa were used were significantly higher than those observed with nontreated spermatozoa (44% versus 24%, 31% versus 2%, respectively). Addition of thioredoxin to preincubation media did not affect the percentage of motility and the fertilization rate but increased the rate of blastocyst formation to an extent similar to that triggered by catalase (2.7- and 3.3-fold, respectively). CONCLUSION(S): These results suggest that H2O2 produced in sperm suspensions before IVF reduces their potential to promote embryo development, that these toxic effects of H2O2 are latent, appearing mainly 3 to 5 days after IVF, and that catalase and thioredoxin are efficient agents to protect sperm potential to support embryo development.

Animals↗
PubMed1996

Cyclic adenosine 3',5'monophosphate-dependent regulation of protein tyrosine phosphorylation in relation to human sperm capacitation and motility.

The involvement of cAMP in the process of sperm capacitation has been the subject of several studies. In addition, the importance of protein-tyrosine phosphorylation in this process has been investigated, although only a few studies have been reported in the human. Since agents regulating the intracellular concentrations of cAMP affect sperm capacitation rates, the role of cAMP on the expression of phosphotyrosine-containing proteins was investigated during human sperm capacitation. Fetal cord serum ultrafiltrate, a known capacitation inducer in human spermatozoa, caused an increase in the phosphotyrosine content of 105- and 81-kDa proteins (p105 and p81), the two major phosphotyrosine-containing proteins of human spermatozoa. Similar effects were observed when spermatozoa were incubated with phosphodiesterase inhibitors or cell-permeant cAMP analogs, suggesting that cAMP is involved in these two processes. Forskolin, an adenylyl cyclase activator, also caused an increase in both sperm capacitation rates and tyrosine phosphorylation of p105 and p81, while 12-O-tetradecanoyl phorbol 13-acetate stimulated both capacitation and tyrosine phosphorylation of p105 and p81 only when spermatozoa were incubated in the presence of bicarbonate, in agreement with its reported effects on cAMP production and hamster sperm capacitation. The inhibition of these phenomena by cAMP-dependent protein kinase inhibitors, and the stimulation by protein phosphatase inhibitors, suggest that Ser/Thr protein phosphorylation plays an important role in the regulation of both sperm capacitation and protein-tyrosine phosphorylation pathways. However, observations that both calyculin A and okadaic acid stimulated sperm capacitation, whereas only calyculin A increased p105 and p81 phosphotyrosine content and sperm velocity, suggest that protein phosphatase PP1 is involved in the two latter phenomena while PP2A mediates sperm capacitation. These results suggest that divergent pathways might regulate tyrosine phosphorylation of p105 and p81 and sperm capacitation after cAMP-dependent phosphorylation of an intermediate protein.

Adenylyl Cyclases↗
PubMed1996

Purification and characterization of the active precursor of a human sperm motility inhibitor secreted by the seminal vesicles: identity with semenogelin.

Human seminal plasma contains a sperm motility inhibitor that originates from seminal vesicles as a precursor form. This precursor is degraded into smaller peptides by prostatic proteases shortly after ejaculation. The seminal plasma sperm motility inhibitor (SPMI) precursor was purified by a combination of cation-exchange chromatography on S-Sepharose followed by C4 reverse-phase high-performance liquid chromatography directly from seminal vesicle fluid or washed seminal coagulum. The purification procedure yielded a protein of apparent homogeneity, with a molecular mass of 52 kDa by SDS-PAGE. It migrated as a 105-kDa protein by molecular sieving under denaturing conditions. The purified SPMI precursor was digested by the prostatic protease prostate-specific antigen (PSA), causing a 76 +/- 4% drop in biological activity and transformation into low molecular mass SPMI polypeptides (5-20 kDa) similar to those observed in liquefied semen. The N-terminal amino acid sequences of three degradation peptides were obtained by Edman degradation and found to correspond to residues 45-50, 85-90, and 137-143 of semenogelin, a protein characterized as the major structural component of semen coagulum. The amino acid composition of SPMI precursor was found to be almost identical to that of semenogelin. Moreover, the mass of the precursor was estimated at 49,620 daltons by electrospray-ionization mass spectrometry, a value in close agreement with the expected mass of semenogelin according to its cDNA sequence. The SPMI precursor was found to inhibit sperm motility in a dose-dependent manner, with complete immobilization at 500 U/ml of SPMI. The motility of completely immobilized spermatozoa was partially recovered after washing of the cells. The results suggest that SPMI precursor is the major component of the seminal vesicle secretions and seminal coagulum. It can be degraded by PSA in a manner reminiscent of its processing in whole semen. Taken together these results indicate that the SPMI precursor is semenogelin and that intact semenogelin can immobilize spermatozoa.

Amino Acid Sequence↗
PubMed1996

The polyglutamylated lateral chain of alpha-tubulin plays a key role in flagellar motility.

To investigate whether a specific isotype of tubulin is involved in flagellar motility, we have developed and screened a panel of monoclonal antibodies (mAb) generated against sea urchin sperm axonemal proteins. Antibodies were selected for their ability to block the motility of permeabilized sperm models. The antitubulin mAb B3 completely inhibited, at low concentrations, the flagellar motility of permeabilized sperm models from four sea urchin species. On immunoblots, B3 recognized predominantly alpha-tubulin in sea urchin sperm axonemes and equally well brain alpha- and beta-tubulins. Subtilisin cleavage of tubulin removed the B3 epitope, indicating that it was restricted to the last 13 amino acid residues of the C-terminal domain of alpha-tubulin. In enzyme-linked immunosorbant assays, B3 reacted with glutamylated alpha-tubulin peptides from sea urchin or mouse brain but did not bind to the unmodified corresponding peptide, indicating that it recognized polyglutamylated motifs in the C-terminal domain of alpha-tubulin. On the other hand, other tubulin antibodies directed against various epitopes of the C-terminal domain, with the exception of the antipolyglutamylated mAb GT335, had no effect on motility while having binding properties similar to that of B3. B3 and GT335 acted by decreasing the beating amplitude without affecting the flagellar beat frequency. B3 and GT335 were also capable of inhibiting the motility of flagella of Oxyrrhis marina, a 400,000,000 year old species of dinoflagellate, and those of human sperm models. Localization of the antigens recognized by B3 and GT335 by immunofluorescence techniques revealed their presence along the whole axoneme of sea urchin spermatozoa and flagella of O. marina, except for the distal tip and the cortical microtubule network of the dinoflagellate. Taken together, the data reported here indicate that the polyglutamylated lateral chain of alpha-tubulin plays a dynamic role in a dynein-based motility process.

Amino Acid Sequence↗
PubMed1995

Analysis of T cell receptor beta chain expression by isoelectric focusing following gene amplification and in vitro translation.

We describe a new approach to analysis of T cell receptor diversity based on isoelectric focusing of in vitro translation products of amplified V region genes. The method is illustrated by analysis of V beta 2 profiles in peripheral blood lymphocytes from normal donors. The primers used for V beta 2 analysis spanned the V-(D-)J junction and included the segment from amino acid residue position 53 in the variable region to residue 132 of the constant region. The isoelectric focusing patterns display approximately 13-14 bands of varying intensity. Differences in expression of V beta 2-derived peptides were detected in comparisons of the isoelectric focusing profiles from different individuals, suggesting that the method may be useful for detecting genetically determined, immune response related or disease associated differences in Tcr V region expression. The major isoelectric focusing bands have been interpreted as representing groups of V beta 2 sequences sharing J beta region and NDN region charge similarity. Quantitative differences were detected in V beta 2 profiles of CD4 and CD8 T cell subpopulations indicating there may be selection for different charge characteristics in NDNJ sequences in the two T cell subsets. The method provides a new dimension for the detection of perturbations in the T cell repertoire.

Base Sequence↗
PubMed1995

Cloning of boar SPMI gene which is expressed specifically in seminal vesicle and codes for a sperm motility inhibitor protein.

Boar semen contains a seminal plasma motility inhibitor (SPMI) that blocks the motility of demembranated-reactivated spermatozoa as well as of intact spermatozoa. In this paper, we describe the primary structure of SPMI, the coding of boar SPMI cDNA gene and its expression in various porcine tissues. Nucleotide sequence analysis of the 645-bp SPMI cDNA predicts a coded polypeptide of 137 amino acid residues which includes a 21-residue signal peptide and a 116-residue secreted protein. The amino acid sequence of SPMI was found to be highly homologous to AQN-3, a member of spermadhesin family proteins of boar that bind to spermatozoa. Expression of the boar SPMI gene detected by Northern blot analysis revealed that its expression is very abundant in seminal vesicles and specific to this tissue.

Amino Acid Sequence↗
PubMed1995

Kindergarten predictors of boys' stable behavior problems at the end of elementary school.

This study predicted stable social maladjustments of ages 10, 11, and 12 from teacher behavioral ratings in kindergarten and a measure of family demographics. Kindergarten teachers rated 1,034 boys on hyperactivity, aggression, inattention, anxiety-withdrawal, and prosocial behavior. Sociodemographic information was collected from the parents. At ages 10, 11, and 12, teacher, parent, peer, and self-report behavior ratings were collected on 743 boys. School achievement was documented from school records. Boys whose average scores on each of the five behavioral ratings across ages 10, 11, and 12 were above the 90th percentile according to at least two informants were defined as having stable behavioral problems. From teacher ratings collected in kindergarten and family demographics, logistic regression analyses predicted stable social maladjustment. For each negative outcome there was a unique set of predictors. The results are discussed with reference to the early identification of children who are at risk.

Achievement↗