Scrotal heat stress induces altered sperm chromatin structure associated with a decrease in protamine disulfide bonding in the stallion.
(1/477)
A variety of testicular insults can induce changes in the structure of spermatozoal chromatin, resulting in spermatozoal DNA that is more susceptible to acid-induced denaturation. The degree of change in the DNA can be measured using the sperm chromatin structure assay (SCSA). The SCSA measures the relative amounts of single- and double-stranded DNA after staining with the metachromatic dye, acridine orange. Here we used a stallion model (n = 4) to study the effects of scrotal heat stress on spermatozoal DNA. This model was created by insulating stallion testes for 48 h and collecting sperm daily thereafter for 60 days. Changes in the SCSA were then correlated with protamine disulfide content and protamine types and levels. Results of the SCSA indicated that the susceptibility of spermatozoal DNA to denaturation was dependent on the spermatogenic cell stage that the ejaculated sperm was in at the time of the heat stress. Spermatozoa with altered DNA had a decrease in the extent of disulfide bonding that was associated with an increase in the susceptibility of DNA to denaturation. However, there were no detectable changes in either the protamine type or level. Thus, in this model, decreased disulfide bonding is associated with an increased susceptibility of spermatozoal DNA to denaturation in the absence of protamine changes. (+info)
Reproductive performance of bulls divergently selected on the basis of blood serum insulin-like growth factor I concentration.
(2/477)
The objectives of this study were to examine differences in scrotal circumference, sperm motility, and percentage of normal sperm cells between two lines of Angus beef cattle divergently selected for blood serum IGF-I concentration. Data were obtained from an ongoing experiment involving 100 spring-calving (50 high and 50 low line) and 100 fall-calving (50 high and 50 low line) purebred Angus cows. Scrotal circumference, percentage of motile sperm cells, and percentage of normal sperm cells did not differ between high and low IGF-I line yearling bulls (P = .79, .50, and .56, respectively). The IGF-I concentrations measured at d 28, 42, and 56 of the postweaning test are abbreviated as IGF28, IGF42, and IGF56, respectively. Coefficients for the quadratic regression of scrotal circumference on IGF28 and IGF42 tended to be negative (P = .07 and .08, respectively), as did the coefficient for the quadratic regression of the percentage of motile sperm cells on IGF42 (P = .08). The coefficient for the linear regression of percentage of normal sperm cells on IGF28 was positive (P = .02). The coefficient for the quadratic regression of percentage of normal sperm cells on IGF56 was negative (P = .04). Coefficients for the quadratic regression of scrotal circumference and percentage of normal sperm cells on mean IGF-I concentrations were negative and important (P = .04 and .08, respectively). Thus, scrotal circumference and percentage of normal sperm cells are related to blood serum IGF-I concentration in yearling Angus bulls. (+info)
Effect of long-term immunization against inhibin on sperm output in bulls.
(3/477)
To determine the effect of neutralization of inhibin on sperm output, 12 Holstein bulls were paired by birth date and weight on Day 1 of age. Each bull was actively immunized against bovine inhibin alpha1-26 gly-tyr (bINH) conjugated to human alpha globulin (HAG, n = 6 bulls) or HAG alone (controls, n = 6) at 60 days of age; booster immunizations were administered at 90, 104, 124, 270, and 395 days of age. Body weights and scrotal circumferences were measured at the time of primary immunization and at 10 days after each booster. In addition, jugular blood was obtained at 60, 70, 100, 114, 134, 280, and 405 days of age, during the 3-wk sperm collection period, and during a 6-h blood-sampling period after sperm collection to determine bINH antibody titer and concentrations of FSH, LH, testosterone, and estradiol. Beginning at 405 days of age, sperm output was measured 3 days/wk for 3 wk with two successive ejaculates collected each day for a total of 18 ejaculates per bull. During Days 60-405 of age, the increase in titer of bINH antibodies, scrotal circumference, and serum concentration of FSH was greater (p < 0.01) for the bINH-immunized compared with control bulls. There were significant (p < 0.01) pair x treatment interactions for sperm output and serum FSH and LH concentrations. Specifically, bINH-immunized bulls for four of the six pairs had nearly 50% greater serum FSH concentrations and sperm output. For the remaining two pairs, sperm output was lower and FSH was either lower or only marginally higher in the bINH-immunized bulls compared with controls. Also, the control bulls for the two remaining pairs produced more sperm than all but one bINH-immunized bull, and had markedly higher serum LH concentrations than all other bulls. To summarize, enhancement of sperm output after immunization against inhibin depends on the subsequent increment in FSH concentrations. We conclude that inhibin suppresses spermatogenesis. Thus, methods to immunoneutralize inhibin may have merit as a therapeutic route to enhance sperm production in reproductively maturing bulls. (+info)
Migration of the abdominal catheter of a ventriculoperitoneal shunt into the scrotum--case report.
(4/477)
A 3-day-old male neonate presented with migration of the ventriculoperitoneal (VP) shunt tip through the patent processus vaginalis resulting in scrotal hydrocele. The association of myelomeningocele with hydrocephalus may have been a predisposing factor in this rare complication. Development of scrotal swelling or hydrocele in a child with VP shunt should be recognized as a possible shunt complication. (+info)
Effects of ambient temperature and scrotal fleece cover on scrotal and testicular temperatures in rams.
(5/477)
The objective was to determine scrotal and testicular temperatures in rams and how they are affected by ambient temperature (10 degrees C vs 25 degrees C) and scrotal fleece (densely fleeced vs shaved). Scrotal surface temperatures (SST) of the caudal aspect of the shaved hemi-scrotum at 10 degrees C vs 25 degrees C were (mean, degrees C) 28.9 and 30.5 (P < 0.03), 28.2 and 29.6 (P < 0.04), and 26.1 and 27.6 (P < 0.06) at the top, middle and bottom of the testis, respectively. Scrotal subcutaneous temperatures (SQT) on the fleeced vs shaved side were 33.5 and 32.0 (P < 0.02), 32.2 and 31.1 (P < 0.06), and 31.7 and 30.8 (P < 0.09) at the top, middle, and bottom at 10 degrees C; they were 33.9 and 32.1 (P < 0.02), 33.1 and 31.9 (P < 0.05), and 32.5 and 32.0 (P < 0.15) at 25 degrees C. Intratesticular temperatures (ITT; measured only at 25 degrees C) on the fleeced vs shaved side were 35.3 and 35.0 (P < 0.5), 35.5 and 35.2 (P < 0.4), and 35.4 and 35.0 (P < 0.3) at the top, middle, and bottom. Temperature gradients (difference from top to bottom) were greatest for SST (2.8 degrees C), moderate for SQT (1.8 to 0.1 degrees C), and not significant for ITT (-0.1 and 0.1 degrees C). The SST was approximately 1.5 degrees C warmer at all 3 locations at 25 degrees C vs 10 degrees C. Increased ambient temperature affected SQT more at the bottom than at the top. Conversely, the difference in SQT between the fleeced and shaved sides was greatest at the top. The difference in ITT (0.3 degrees C warmer on the fleeced vs the shaved side at all locations) was not significant. Therefore, the magnitude of temperature increase associated with ambient temperature or scrotal fleece was affected by both depth and vertical location. (+info)
Reproductive and endocrine function in rams exposed to the organochlorine pesticides lindane and pentachlorophenol from conception.
(6/477)
There is controversy over the potential endocrine modulating influence of pesticides, particularly during sensitive phases of development. In this study, ram lambs were exposed to lindane and pentachlorophenol from conception to necropsy at 28 weeks of age. The rams (and their mothers) were given untreated feed (n = 7) or feed treated with 1 mg kg-1 body weight per day of lindane (n = 12) or pentachlorophenol (n = 5). Semen was collected from 19 weeks onwards and reproductive behaviour was tested at 26 weeks. Serum was collected every 2 weeks and at 27 weeks every 15 min for 6 h during both day and night, and for 1 h before and 5 h after stimulation with GnRH, adrenocorticotrophic hormone and thyroid-stimulating hormone. The pesticides did not affect body weight and ejaculate characteristics, or cause overt toxicity. In pentachlorophenol-treated rams, scrotal circumference was increased. However, seminiferous tubule atrophy was more severe and epididymal sperm density was reduced in comparison with untreated rams at necropsy (P < 0.05). Thyroxine concentrations were lower in pentachlorophenol-treated rams than in untreated rams (P < 0.05). However, after thyroid-stimulating hormone treatment, the thyroxine response was unaltered. Reproductive behaviour was reduced in lindane-treated rams compared with control rams (P < 0.05). Serum LH and oestradiol concentrations during reproductive development, LH pulse frequency at 27 weeks and testosterone secretion after GnRH treatment were lower in lindane-treated rams than in untreated rams (P < 0.05). In summary, the effects of pentachlorophenol on the testis may be linked to a decrease in thyroxine concentrations, and reduced reproductive behaviour in lindane-treated rams may be related to decreased LH, oestradiol and testosterone concentrations. (+info)
Proposed panel of diagnostic criteria, including the use of ultrasound, to refine the concept of 'endemic normals' in lymphatic filariasis.
(7/477)
Although living adult Wuchereria bancrofti worms can be detected by ultrasound examination of the scrotal area in approximately 80% of men infected with this filarial parasite, the location of the adult worms in the remaining 20% remains unclear. To determine this, 32 individuals who had W. bancrofti microfilaraemia but no adult worms detectable on ultrasound were treated with diethylcarbarmazine (DEC), either with a single 6 mg/kg dose (n = 13) or with a 12-day course of 6 mg/kg per day (n = 19). They were then monitored with serial physical and ultrasound examinations. Thirteen (41%) subjects developed small, single scrotal nodules 12 h to 7 days after treatment; this rate was unaffected by the dose of DEC. No nodules were detected outside the scrotal area. All 5 men with lymphangiectasia suspected on ultrasound before treatment developed scrotal nodules, compared to 8 (29.6%) of 27 men without ultrasonographic evidence (P = 0.006). Thus, using both ultrasound and 'provocative' treatment with DEC, adult W. bancrofti can be detected in the scrotal area of an estimated 88% of infected men. Because no single diagnostic test for W. bancrofti infection is completely sensitive, a panel of tests, including ultrasound, is proposed to identify with greater accuracy 'endemic normals' for immunological and epidemiological studies. (+info)
Additive genetic relationships between heifer pregnancy and scrotal circumference in Hereford cattle.
(8/477)
The objective of this study was to determine an appropriate method for using yearling scrotal circumference observations and heifer pregnancy observations to produce EPD for heifer pregnancy. We determined the additive genetic effects of and relationship between scrotal circumference and heifer pregnancy for a herd of Hereford cattle in Solano, New Mexico. The binary trait of heifer pregnancy was defined as the probability of a heifer conceiving and remaining pregnant to 120 d, given that she was exposed at breeding. Estimates of heritability for heifer pregnancy and scrotal circumference were .138+/-.08 and .714+/-.132, respectively. Estimates of fixed effects for age of dam and age were significant for heifer pregnancy and bull scrotal circumference. The estimate of the additive genetic correlation between yearling heifer pregnancy and yearling bull scrotal circumference was .002+/-.45. Additional analyses included models with additive genetic groups for scrotal circumference EPD for heifer pregnancy or heifer pregnancy EPD for scrotal circumference to account for a potential nonlinear relationship between scrotal circumference and heifer pregnancy. Results support the development of a heifer pregnancy EPD because of a higher estimated heritability than previously reported. The development of a heifer pregnancy EPD would be an additional method for improving genetic merit for heifer fertility. (+info)