Neoplasia of the male reproductive tract

Genital neoplasms in the male horse are relatively uncommon. Squamous cell carcinomas and squamous papillomas are the most commonly diagnosed neoplasms of the penis and prepuce. Geldings appear to be overrepresented for these types of neoplasms, and accumulation of smegma may be a contributing factor. Early diagnosis and treatment are essential for salvaging these organs before lesions become excessively large and invasive or are allowed to metastasize. Newer treatment modalities such as 5-fluorouracil appear to be promising alternatives to surgical excision. Although generally considered to be uncommon, testicular tumors may occur more frequently than previously thought and have the potential for devastating effects on stallion fertility. Cryptorchidism appears to play a role in the development of equine testicular tumors, especially teratomas. Seminoma is by far the most common testicular tumor of the mature stallion. Seminomas are rapidly growing tumors with a greater potential to metastasize in the horse than in other domestic species. Leydig cell and Sertoli cell tumors have been reported but are relatively rare in the stallion. Orchiectomy is the standard treatment for most testicular tumors. In certain circumstances, however, such as neoplasia occurring in the only functional testis, local cryotherapy of testicular tumors may prolong the breeding career of an affected stallion.     

Obstruction of the male reproductive tract

Anatomic obstruction of the male reproductive ducts may be congenital, inflammatory or iatrogenic in origin. Two cases of congenital obstruction and 1 case of iatrogenic obstruction are presented. Accurate identification of the etiology and location of the obstruction is necessary for patient counseling and choice of treatment.     

High divergence of reproductive tract proteins and their association with postzygotic reproductive isolation in Drosophila melanogaster and Drosophila virilis group species

The possible association between gonadal protein divergence and postzygotic reproductive isolation was investigated among species of the Drosophila melanogaster and D. virilis groups. Protein divergence was scored by high-resolution two-dimensional electrophoresis (2DE). Close to 500 protein spots from gonadal tissues (testis and ovary) and nongonadal tissues (malpighian tubules and brain) were analyzed and protein divergence was calculated based on presence vs absence. Both testis and ovary proteins showed higher divergence than nongonadal proteins, and also a highly significant positive correlation with postzygotic reproductive isolation but a weaker correlation with postzygotic reproductive isolation. Particularly, a positive and significant correlation was found between proteins expressed in the testis and postzygotic reproductive isolation among closely related species such as the within-phylad species in the D. virilis group. The high levels of male-reproductive-tract protein divergence between species might be associated with F1 hybrid male sterility among closely related species. If so, a lower level of ovary protein divergence should be expected on the basis that F1 female hybrids are fully fertile. However, this is not necessarily true if relatively few genes are responsible for the reproductive isolation observed between closely related species, as recent studies seem to suggest. We suggest that the faster rate of evolution of gonadal proteins in comparison to nongonadal proteins and the association of that rate with postzygotic reproductive isolation may be the result of episodic and/or sexual selection on male and female molecular traits.     

Effects of dimethylpyrazine isomers on reproductive and accessory reproductive organs in male rats

Glycosyl-phosphatidylinositol-specific phospholipase D (GPI-PLD) is an amphiphilic protein which, in serum, is associated with high-density lipoproteins (HDL). It is shown that the major component of the HDL fraction, apolipoprotein A-I (apo A-I), is responsible for this association. In the absence of apo A-I, purified GPI-PLD occurred as virtually inactive aggregates which became disaggregated by apo A-I. The enzyme/apo A-I complex efficiently hydrolyzed the solubilized GPI-anchored substrate, acetylcholinesterase. Triton X-100 was also able to dissociate aggregated GPI-PLD, however, it strongly inhibited enzyme activity at detergent concentrations above the critical micellar concentration.     

Female x male interactions in Drosophila sperm competition

In several organisms, the success of a male's sperm in multiply inseminated females depends on the male's genotype. In Drosophila, the female also plays a role in determining which sperm are successful. Pairwise tests among six isogenic lines of Drosophila melanogaster were performed to determine whether there is a genotype-specific interaction in the success of sperm. The success of a particular male's sperm was found to depend on the genotype of the female with which he mates, providing evidence for an interaction with profound evolutionary consequences.     

Formation of the male pronuclear lamina in Drosophila melanogaster

E. coli homologs of the signal recognition particle (SRP) and its receptor are essential for viability, but their role in protein export is unclear. To elucidate their function, we devised a genome-wide screen to identify genes that encode SRP substrates. Inhibition of the SRP pathway sharply blocked the membrane insertion of several polytopic inner membrane proteins (IMPs) that were predicted to be SRP substrates, but had a smaller effect on the insertion of other IMPs and no significant effect on preprotein translocation. Our results suggest that whereas most E. coli preproteins and some IMPs can utilize SRP-independent targeting pathways effectively, the structural features of a subset of IMPs have required the conservation of an SRP-based targeting machinery.     

A role for oestrogens in the male reproductive system

Oestrogen is considered to be the 'female' hormone, whereas testosterone is considered the 'male' hormone. However, both hormones are present in both sexes. Thus sexual distinctions are not qualitative differences, but rather result from quantitative divergence in hormone concentrations and differential expressions of steroid hormone receptors. In males, oestrogen is present in low concentrations in blood, but can be extraordinarily high in semen, and as high as 250 pg ml(-1) in rete testis fluids, which is higher than serum oestradiol in the female. It is well known that male reproductive tissues express oestrogen receptors, but the role of oestrogen in male reproduction has remained unclear. Here we provide evidence of a physiological role for oestrogen in male reproductive organs. We show that oestrogen regulates the reabsorption of luminal fluid in the head of the epididymis. Disruption of this essential function causes sperm to enter the epididymis diluted, rather than concentrated, resulting in infertility. This finding raises further concern over the potential direct effects of environmental oestrogens on male reproduction and reported declines in human sperm counts.     

Genistein exerts estrogen-like effects in male mouse reproductive tract

The 'retention analysis method', which is based on size-exclusion chromatography (SEC) in conjunction with an arsenic-specific detector (graphite furnace atomic absorption spectrometer, GFAAS), was used to study the effect of pH (range 2.0-10.0), temperature (4, 25 and 37 degrees C), and the concentration of glutathione in the mobile phase (0.5-7.5 mM) on the formation of arsenic-glutathione species after injection of sodium arsenite using phosphate-buffered saline solutions as mobile phases. The formation of arsenic-GSH species was facilitated by low temperatures (4 degrees C), pH 6.0-8.0 and high concentrations of glutathione (7.5 mM) in the mobile phase. Simulating the physicochemical parameters found inside human red blood cells (approximately 3.0 mM glutathione, 37 degrees C, pH 7.4) and hepatocytes (approximately 7.5 mM glutathione, 37 degrees C, pH 7.4), SEC-GFAAS provided evidence for the formation of arsenic-glutathione species under these conditions. In addition, the 'chelating agent', sodium DL-2,3-dimercapto- -propanesulfonate (1.0 and 2.0 mM) was demonstrated to bind arsenous acid stronger in the presence of glutathione (7.5 mM) under these conditions (PBS buffer, pH 7.4, 37 degrees C).     

Causes of reproductive age mortality in low socioeconomic settlements of Karachi

The Maternal and Infant Mortality Survey (MIMS) was conducted in eight squatter settlements of Karachi. The female mortality rate was 151.0 per 100,000 women aged 10-49 years and the maternal mortality ratio was 281 per 100,000 livebirths. The leading causes of deaths among women were complications of pregnancy (28.1%), infectious diseases (24.8%), cardiovascular diseases (20.7%), neoplasia (10.7%) and trauma (10.7%). Hemorrhage (47.1% of all maternal deaths), tuberculosis (40.0% of all infectious disease deaths), oropharyngeal cancer (23.1% of all neoplastic deaths), and burns (61.5% of all trauma deaths) were among the major causes identified. Maternal deaths were associated with young age and nulliparity (p-value < 0.01), and a higher proportion occurred in the hospital or on the way to the hospital as compared to non-maternal deaths.     

Paternal care enhances male reproductive success in pine engraver beetles

His117 of the D2 protein of photosystem II (PS II) is a conserved residue in the second transmembrane region of the protein and has been suggested to bind chlorophyll. Nine site-directed mutations were introduced at residue 117, using both photosystem I (PS I)-containing and PS I-less background strains of the cyanobacterium Synechocystis sp. PCC 6803. Of these nine, four (H117C, H117M, H117N, and H117T) were photoautotrophic in the PS I-containing background. The other mutants (H117F, H117L, H117P, H117R, and H117Y) did not accumulate appreciable amounts of PS II in their thylakoids. The type of residues that can functionally replace His117 support the notion of His117 serving as a chlorophyll ligand. The properties of the H117N and H117T mutants were characterized in more detail. Whereas the properties of the H117N mutant were close to those of wild type, in the H117T mutant the 77-K fluorescence emission spectrum shows a much smaller amplitude at 695 nm than expected on the basis of the amount of PS II that is present. Moreover, in H117T, the amount of light needed to half-saturate O2-evolution rates was twofold higher than in the control strain, and the variable fluorescence yield was quenched. However, O2 evolution rates at saturating light intensity and electron-transport kinetics were normal in the mutant. Also, the radical accessory chlorophyll (Chlz+) formed by donation of an electron to the PS-II reaction center could be generated normally by illumination at low temperature in the H117T mutant. We conclude that the chlorophyll associated with residue 117 of the D2 protein is important for efficient excitation transfer between the proximal antenna and the PS II reaction center. A possible mechanism involving a chlorophyll cation to explain the quenching in the H117T mutant is discussed.     

Ganciclovir induces reproductive hazards in male rats after short-term exposure

1. The effect of short-term treatment of ganciclovir on male reproduction in adult rats was studied. The animals were treated subcutaneously with either a single dose of 60 mg/kg daily for 5 days (Gan5day) or with 100 mg/kg administered three times at 4 h-intervals (Gan1day). The effects were investigated every 2 weeks up to 8 weeks, followed by investigations 16 and 24 weeks after treatment to detect the potential of recovery. 2. Time to mating was significantly increased in Gan1day group. The pregnancy index and outcome were only decreased 8 weeks (Gan5day and Gan1day) or 16 weeks (Gan1day) after treatment. 3. The lowest values of sperm variables studied were registered 8 weeks after treatment: The number of spermatid was reduced up to 4% (Gan5day) or 2% (Gan1day) of control; the sperm number was 5% and 8% of control in Gan5day and Gan1day, respectively. Over 80% of sperm were abnormal in Gan5day group, and only few normal sperm was detected in Gan1day group. 4. Morphological investigation of testes revealed a clearcut time-dependency effect. Four weeks after treatment distinct alterations were located exclusively in the peripheral part of the tubuli which included fat inclusions, cell and pyknotic nuclear debris and swellings of Sertoli cells. The effect was reversible 24 weeks after treatment. 5. Ganciclovir induces testicular damage and affects sperm variables after short-term exposure. The intensity and degree of the hazards varied in between the time of investigation after treatment.     

How accurate is male recall of reproductive information?

The purpose of this study was to determine how well men recall reproductive information. By using a questionnaire, the authors surveyed men who had undergone orchiopexy for undescended testes and a group of matched control men, all of whom had had surgery at the Children's Hospital of Pittsburgh in Pittsburgh, Pennsylvania (n = 77), and their spouses. Subjects were a random subset of a larger (n = 1,212) male fertility study, which has been ongoing since 1992. In 1994, the spouses of men who participated in the study completed a short telephone survey that contained questions previously asked of their partners. Pearson correlations and kappa statistics were calculated to evaluate the accuracy of male recall of reproductive information. For the continuous measures, such as time to conception and frequency of intercourse, the correlations were high to moderate (r = 0.84 (p < 0.001) and r = 0.45 (p < 0.001), respectively). Agreement between the men and their spouses on the majority of bivariate (yes/no) questions, such as those concerning the use of birth control, as measured by the kappa statistic, was moderate to very good (K ranged from 0.14 to 0.69). Statistics were similar for formerly cryptorchid and control men. Male participants' responses to questions about their reproductive histories were accurate as compared with the responses given by their spouses. In this sample from a large cohort study, men appeared to recall reproductive information with acceptable accuracy.     

Control of reproductive behavior by sex steroids in male quail.

Conducted 2 experiments on the ability of different sex steroids to stimulate crowing, strutting, and copulation. Exp I with 32 male Japanese quail was designed to maximize crowing. Intact untreated males and castrated males treated with 2 dosages of testosterone propionate (TP), with 2 dosages of dihydrotestosterone propionate (DHTP), or with oil were tested. The DHTP-treated males crowed extensively; TP-treated males crowed, but to a lesser extent than DHTP-treated males. In Exp II (30 Ss), which was designed to maximize strutting and copulation, males with photically regressed testes were treated with DHTP, DHTP?+?estradiol benzoate (EB), or EB alone and were tested with female partners. The DHTP-treated males did not copulate, but 2 birds strutted. The EB-treated males copulated but did not strut. Males receiving DHTP?+?EB strutted and copulated. These results suggest that (a) copulation in quail may involve conversion of testosterone to estrogen by the brain; (b) crowing and strutting may involve conversion of testosterone to dihydrotestosterone by the brain; and (c) in quail, the different components of male reproductive behavior show divergent patterns of hormone responsiveness, and thus the neural tissues underlying these behaviors have different molecular requirements for activation by steroids. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New genes for male accessory gland proteins in Drosophila melanogaster

The accessory gland of male insects produces components of the seminal fluid that alter the behavior, physiology and life span of the mated female, and contribute to her efficient storage and utilization of sperm. As a step towards understanding how this occurs, we have isolated genes encoding 12 previously unreported accessory gland-specific mRNAs from the fruit fly Drosophila melanogaster. We report here the restriction maps of the new genes, the chromosome positions--which are all autosomal--of the 11 non-repetitive genes, their expression patterns, and the sequences of the accessory gland proteins (Acps) encoded by nine of the genes. Eight of the proteins predicted from these sequences begin with putative secretion signals. Following their signal sequences, three of the predicted molecules are peptides and the other five are larger polypeptides with characteristics of cleavable prohormones. The ninth molecule, which has an N-terminal hydrophobic region but no consensus signal peptide cleavage site, is predicted to be a 716 amino acid glycoprotein. Of the nine proteins, two have intriguing similarities to sequences in protein databases. Acp76A is a 388 amino acid pro-protein which contains a signature sequence for the serpin class of protease inhibitors. The 115 amino acid Acp62F has a 28 amino acid region of high sequence similarity to a neurotoxin of the Brazilian armed spider Phoneutria nigriventer. Models are discussed in which Acp76A plays a role in the observed regulation of Acp proteolysis and/or in the coagulation of seminal fluid to form a mating plug, and in which Acp62F contributes to the reported toxicity of Drosophila seminal fluid.     

The accumulation of P-element-induced recombinants in the germline of male Drosophila melanogaster

P-element-induced recombination in Drosophila melanogaster occurs premeiotically. Recombinants are therefore expected to accumulate in the stem cells of the germline of P-element-carrying males. We show that both the recombination frequency and the incidence of "clustering" increase with the age of males carrying various P-element derivatives. The combination of end-deleted elements can lead to average recombination frequencies >50% with individual instances of 100% recombination. These elements also lowered the fertility of the carriers. We investigated these features by constructing an analytical and a computer simulation model of the course of events in the germline, incorporating the recently proposed hybrid element insertion (HEI) model of P-element activity. The model is able to predict extreme recombination levels, segregation ratio biases and lowered fertility through cell death in a single analysis.     

Electrophysiological and ultrasonic correlates of reproductive behavior in the male rat.

Monitored the ultrasonic vocalizations of 13 male Long-Evans rats and determined the correlation of these vocalizations with electrophysiological activity measured by chronically implanted hippocampal and cortical electrodes during mating with a female rat. Hippocampal theta rhythms were significantly correlated with high activity, mounting, intromissions, and preejaculatory excitatory behavior and were also significantly associated with 50-kHz short ultrasonic vocalizations. Postmount or postintromission behaviors (grooming, exploration) were closely correlated with an absence of ultrasonic vocalizations and the onset of irregular low-amplitude hippocampal EEG recordings. Long 22-kHz vocalizations occurred during the postejaculatory refractory period. Shorter 22-kHz vocalizations occurred during mating and were associated with unsuccessful intromissions or mounting attempts. Postejaculatory long 22-kHz vocalizations were significantly associated with irregular high-amplitude hippocampal EEG tracings, while preejaculatory short 22-kHz vocalizations were also accompanied by sleeplike irregular high-amplitude hippocampal EEG tracings with cortical spindling. Findings suggest that ultrasonic vocalizations are indicators of the sexual arousal of mating rats. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Melatonin, immunity and cost of reproductive state in male European starlings

The effects of reproductive condition and exogenous melatonin on immune function were investigated in castrated European starlings, Sturnus vulgaris. Photorefractory and photostimulated starlings exposed to long days were implanted with melatonin or with blank capsules. Photostimulated starlings with blank capsules exhibited reduced splenocyte proliferation in response to the T-cell mitogen, concanavalin A, compared with the other long-day birds. Exogenous melatonin prevented the suppression of immune function by photostimulation. Photorefractory starlings, with or without melatonin implants, exhibited enhanced immune function compared with photostimulated starlings implanted with blanks. This enhancement was not mediated by endogenous melatonin, but appeared to be related to changes in reproductive state. In addition to the traditional costs of reproduction in birds (e.g. raising of young), there may be a cost of the reproductive state of starlings (i.e. whether they are photorefractory or photostimulated). These data are, we believe, the first to indicate a direct effect of reproductive state on immune function that is independent of both photoperiod (i.e., changes in the duration of melatonin secretion) and gonadal steroids.     

Delayed male maturity is a cost of producing large sperm in Drosophila

Among fruit-fly species of the genus Drosophila there is remarkable variation in sperm length, with some species producing gigantic sperm (e.g., > 10 times total male body length). These flies are also unusual in that males of some species exhibit a prolonged adult nonreproductive phase. We document sperm length, body size, and sex-specific ages of reproductive maturity for 42 species of Drosophila and, after controlling for phylogeny, test hypotheses to explain the variation in rates of sexual maturation. Results suggest that delayed male maturity is a cost of producing long sperm. A possible physiological mechanism to explain the observed relationship is discussed.