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4. Differences in the quality of semen in outdoor workers during summer and winter

Author

Levine, Richard J., Mathew, Ravi M., Chenault, C. Brandon, Brown, Michelle H., Hurtt, Mark E., Bentley, Karin S., Mohr, Kathleen L., and Working, Peter K.

Subjects
Semen -- Measurement, Spermatogenesis -- Environmental aspects, Man, Spermatogenesis -- Physiological aspects
Abstract

In nonequatorial areas of the globe with warm climates, fewer babies are born in the spring. This could result from lower sperm quality nine months earlier, possibly as a result of exposure of the scrotum (the sac holding the testicles) to greater summer heat. To evaluate sperm quality, researchers collected sperm from 131 outdoor workers (average age, 32) during the summer (August) and winter (February), to allow comparison of sperm characteristics for the same men sampled at two different times. The study was performed in San Antonio, Texas, where the average summer temperature is 35.9 degrees Centigrade (96.6 degrees Fahrenheit), and the average winter temperature, 17.7 degrees (63.9 degrees F.). Data regarding the men's drug use, health, type of work performed, marital history, and related factors were obtained. Videotape recordings of semen specimens were analyzed to determine the percentage of motile (moving) sperm, sperm velocity, the number of beats per unit time of the flagella (tails of the sperm), and other characteristics related to sperm quality. Results showed that this group of men were more likely than the average American male to smoke and to consume two or more alcoholic drinks per day. About one third of the men performed construction work, 17 percent did landscaping, and eight percent drove a motor vehicle. In summer, sperm concentration, sperm count per ejaculate, and the concentration of motile sperm were lower than in winter (by 29, 23, and 26 percent, respectively). Other characteristics, such as volume of seminal fluid, percentage of motile sperm, characteristics of sperm movement, and length of sexual abstinence, did not differ between seasons. No correlation was observed between the number of hours a man worked outside, and seasonal differences in sperm characteristics. The results parallel those of other studies, which are discussed. Several factors, including the lower summer sperm counts among men in cooler climates, and the peak in birth rates in the spring in Europe (in spite of decreased sperm counts in the summer), imply that heat is not a complete explanation for birth rate effects. (Consumer Summary produced by Reliance Medical Information, Inc.)

Published
1990

37. Methods for assessing sperm motility, morphology, and counts in the rat, rabbit, and dog: A consensus report

Author

Seed, Jennifer, primary, Chapin, Robert E., additional, Clegg, Eric D., additional, Dostal, Lori A., additional, Foote, Robert H., additional, Hurtt, Mark E., additional, Klinefelter, Gary R., additional, Makris, Susan L., additional, Perreault, Sally D., additional, Schrader, Steve, additional, Seyler, David, additional, Sprando, Robert, additional, Treinen, Kimberley A., additional, Veeramachaneni, D.N.Rao, additional, and Wise, L.David, additional

Published
1996
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46. Object Discrimination Reversal As a Method to Assess Cognitive Impairment in Nonhuman Primate Enhanced Pre- and Postnatal Developmental (e PPND) Studies: Statistical Power Analysis.

Author

Cappon, Gregg D., Bowman, Christopher J., Hurtt, Mark E., and Grantham, Lonnie E.

Abstract

An important aspect of the enhanced pre- and postnatal developmental (e PPND) toxicity study in nonhuman primates ( NHP) is that it combines in utero and postnatal assessments in a single study. However, it is unclear if NHP e PPND studies are suitable to perform all of the evaluations incorporated into rodent PPND studies. To understand the value of including cognitive assessment in a NHP e PPND toxicity study, we performed a power analysis of object discrimination reversal task data using a modified Wisconsin General Testing Apparatus ( ODR- WGTA) from two NHP e PPND studies. ODR- WGTA endpoints evaluated were days to learning and to first reversal, and number of reversals. With α = 0.05 and a one-sided t-test, a sample of seven provided 80% power to predict a 100% increase in all three of the ODR- WGTA endpoints; a sample of 25 provided 80% power to predict a 50% increase. Similar power analyses were performed with data from the Cincinnati Water Maze ( CWM) and passive avoidance tests from three rat PPND toxicity studies. Groups of 5 and 15 in the CWM and passive avoidance test, respectively, provided 80% power to detect a 100% change. While the power of the CWM is not far superior to the NHP ODR- WGTA, a clear advantage is the routine use of larger sample size, with a group of 20 rats the CWM provides ∼90% power to detect a 50% change. Due to the limitations on the number of animals, the ODR- WGTA may not be suitable for assessing cognitive impairment in NHP e PPND studies. [ABSTRACT FROM AUTHOR]

Published
2012
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47. Toxicity study in juvenile rats with the α4β2 nicotinic acetylcholine receptor partial agonist CP-601,927.

Author

Campion, Sarah N., Hurtt, Mark E., Chatman, Linda A., and Cappon, Gregg D.

Abstract

BACKGROUND: CP-601927 is a selective α4β2 nicotinic acetylcholine receptor (nAChR) partial agonist. The objective of this study was to assess the potential effects persisting into adulthood when CP-601,927 was administered to neonatal/juvenile rats. Since the juvenile toxicity study was being performed early in the development program and this study would represent the longest dosing period yet evaluated, the study design incorporated standard endpoints typically evaluated in a general toxicity screening study. METHODS: CP-601,927 was administered to Sprague-Dawley rats from postnatal day (PND) 7-70 by oral gavage at doses of 0.3, 1, or 3 mg/kg. During treatment animals were evaluated for growth, development, and sexual maturation. At the end of the treatment period general toxicity screening endpoints were collected (e.g., organ weights, histology, clinical chemistry). Following a 2-week latency period, animals were evaluated for CNS function in a comprehensive behavioral training battery consisting of a functional observational battery, motor activity, acoustic startle response, and learning and memory evaluations. Reproductive competency was evaluated by mating treated rats and allowing pregnant dams to deliver and rear their litters until PND 10. RESULTS AND CONCLUSIONS: Treatment-related findings included the death of 2 males receiving 3 mg/kg CP-601,927, and transient reductions in body weight for both males and females during the third week of dosing which quickly recovered to control levels. The only treatment-related alteration in behavior was decreased motor activity, which occurred only in females at the highest dose tested. CP-601,927 had no effect on acoustic startle response, learning and memory, sexual maturation, reproductive capacity, or general toxicity endpoints. Birth Defects Res (Part B) 92:323-332, 2011. © 2011 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Published
2011
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