Biomedical subjects

Zuying Chen

Publications and source records attributed to Zuying Chen.

8 recordsLinked to original sources

PubMed2005

Does the potential for selection bias in semen quality studies depend on study design? Experience from a study conducted within an infertility clinic.

BACKGROUND: The low participation rates in human semen quality studies raises concern for the potential of differential participation based on semen quality (or a surrogate). To explore the potential for differential participation, we compared semen analysis results from study subjects with those of non-study subjects. METHODS: We obtained semen analysis results from 235 study subjects and retrospectively obtained results from a subset of 235 infertility clinic patients that were not study subjects but met the same eligibility criteria. The study was conducted at the Massachusetts General Hospital Infertility Clinic. All semen samples (study subjects and non-study subjects) were analysed for sperm concentration and motility by computer-aided semen analysis (CASA), and morphology was assessed using strict criteria. Semen analysis parameters for the non-study subjects were compared with the semen analysis results from study subjects. RESULTS: For all semen characteristics (sperm concentration, total sperm count, sperm motility and morphology), there were only marginal (non-significant) differences between study subjects and non-study subjects. CONCLUSIONS: Among men from an infertility clinic, we found no strong evidence of differential participation based on semen quality. This is reassuring since the potential for selection bias is of concern in semen quality studies. However, the potential for selection bias in other study designs remains unclear.

Ambulatory Care Facilities↗

PubMed2004

Impact of seasonal variation, age and smoking status on human semen parameters: The Massachusetts General Hospital experience.

BACKGROUND: To investigate the relationship of human semen parameters with season, age and smoking status. METHODS: The present study used data from subjects recruited into an ongoing cross-sectional study on the relationship between environmental agents and semen characteristics. Our population consisted of 306 patients who presented to the Vincent Memorial Andrology Laboratory of Massachusetts General Hospital for semen evaluation. Sperm concentration and motility were measured with computer aided sperm analysis (CASA). Sperm morphology was scored using Tygerberg Kruger strict criteria. Regression analyses were used to investigate the relationships between semen parameters and season, age and smoking status, adjusting for abstinence interval. RESULTS: Sperm concentration in the spring was significantly higher than in winter, fall and summer (p < 0.05). There was suggestive evidence of higher sperm motility and percent of sperm with normal morphology in the spring than in the other seasons. There were no statistically significant relationships between semen parameters and smoking status, though current smokers tended to have lower sperm concentration. We also did not find a statistically significant relationship between age and semen parameters. CONCLUSIONS: We found seasonal variations in sperm concentration and suggestive evidence of seasonal variation in sperm motility and percent sperm with normal morphology. Although smoking status was not a significant predictor of semen parameters, this may have been due to the small number of current smokers in the study.

Journal Article↗

PubMed2003

The relationship between human semen parameters and environmental exposure to polychlorinated biphenyls and p,p'-DDE.

Scientific and public concern exists about potential reproductive health effects of persistent chlorinated organic chemicals, such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), and dichlorodiphenyldichloroethylene (DDE, the most stable daughter compound of DDT). To explore the hypothesis that environmental exposures to PCBs and DDE are associated with altered semen parameters, we conducted a cross-sectional study of 212 male partners of subfertile couples who presented to the Massachusetts General Hospital Andrology Laboratory. Semen parameters were analyzed as both a continuous measure and dichotomized based on World Health Organization reference values for sperm concentration (< 20 million/mL), motility (< 50% motile), and Kruger strict criteria for morphology (< 4% normal). The comparison group for the dichotomized analysis was men with all three semen parameters above the reference values. In serum, 57 PCB congeners and p,p -DDE were measured by congener-specific analysis using gas chromatography with electron capture detection. There were dose-response relationships among PCB-138 and sperm motility (odds ratio per tertile, adjusted for age, abstinence, and smoking, and p-value for trend were, respectively, 1.00, 1.68, 2.35, and p-value = 0.03) and morphology (1.00, 1.36, 2.53, p-value = 0.04). There was limited evidence of an inverse relationship between sum of PCBs, as well as those PCBs classified as cytochrome P450 enzyme inducers, with sperm motility and sperm morphology, as well as limited evidence of an inverse association between p,p -DDE and sperm motility. The lack of a consistent relationship among semen parameters and other individual PCB congeners and groupings of congeners may indicate a difference in spermatotoxicity between congeners.

Adult↗

PubMed2003

Phthalate exposure and human semen parameters.

BACKGROUND: There is scientific and public concern about commonly used chemicals, including phthalates, that are associated with reproductive toxicity in laboratory animals and are hormonally active. People are exposed to phthalates through diet, consumer products and medical devices. The present study explored whether environmental levels of phthalates are associated with altered semen quality in humans. METHODS: We recruited 168 men who were part of subfertile couples and who presented to the Massachusetts General Hospital andrology laboratory for semen analysis between January 2000 and April 2001. Semen parameters were dichotomized based on 1999 World Health Organization reference values for sperm concentration (< 20 million/ml) and motility (< 50% motile), as well as Tygerberg Strict criteria for morphology (< 4% normal). The comparison group was men for whom these semen parameters were all above the reference values. In urine, eight phthalate metabolites were measured with high-performance liquid chromatography and tandem mass spectrometry. Specific gravity-adjusted phthalate metabolite levels were categorized into tertiles. RESULTS: There was a dose-response relation between tertiles of mono-butyl phthalate and sperm motility (odds ratio per tertile = 1.0, 1.8, 3.0; P-value for trend = 0.02) and sperm concentration (1.0, 1.4, 3.3; P-value for trend = 0.07). In addition, there was a dose-response relation between tertiles of mono-benzyl phthalate and sperm concentration (1.0, 1.4, 5.5; P-value for trend = 0.02). CONCLUSIONS: There were dose-response relations for monobutyl phthalate and monobenzyl phthalate with one or more semen parameters, and suggestive evidence for monomethyl phthalate with sperm morphology. The lack of a relation for other phthalates may indicate a difference in spermatotoxicity among phthalates.

Adult↗

PubMed2002

Environmental organochlorines and semen quality: results of a pilot study.

There have been numerous studies that suggest that sperm concentrations (sperm counts) are declining in men. However, other studies suggest that sperm counts are not declining or may be increasing in some areas. Although there is disagreement on whether there is a downward temporal trend in sperm counts, the studies provide evidence that sperm counts vary by geographic location. It has been hypothesized that the geographic variation in sperm concentrations may be due to environmental exposures, lifestyle factors, or some unknown causes. To determine whether contemporary ambient levels of polychlorinated biphenyls (PCBs) and p,p-DDE are associated with altered semen quantity and quality, we selected a study population without specific exposure to PCBs or p,p-DDE. The present study presents the results from a pilot study on the relationship between serum PCBs and p,p-DDE and semen quality in 29 subjects recruited from the Massachusetts General Hospital Andrology Laboratory. Of the 29 subjects, 3 had sperm concentrations < 20 million/mL, 7 had < 50% motile sperm, 9 had < 4% normal morphology, and 6 were below normal in more than one semen parameter. The 18 subjects with normal spermatozoa concentration, motility, and morphology were used as comparison subjects. The mean (SE) concentration of the sum of PCBs and p,p-DDE was 242 ng/g lipids (34.0) and 354 ng/g lipids (120), respectively, for men with below normal motility as compared to 202 ng/g lipids (16.6) and 240 ng/g lipids (31.1), respectively, for the comparison subjects. The data showed general trends that were suggestive of an association between PCBs and p,p-DDE and abnormal motility, as well as with sperm concentration and morphology. A full-scale study is currently in progress.

Adult↗

PubMedDate not supplied

Seasonal variation and age-related changes in human semen parameters.

Although semen quality has been discussed extensively with regard to age and season in the andrology literature, the results vary and firm conclusions are still outstanding. To investigate seasonal and age-related variations in human semen parameters, we analyzed data that were collected from an andrology clinic population. We performed a retrospective review of 551 semen analysis records collected from 1989 to 2000 from the Vincent Memorial Andrology Laboratory at Massachusetts General Hospital. Semen volume, sperm concentration, total sperm count, motility, total motile sperm, and morphology significantly decreased as age increased. In addition, as age increased, the percentage of sperm with tail defects increased. Sperm concentration was significantly higher in winter (mean 157.9 million/mL) than in fall (mean 119.1 million/mL) (P <.05). The mean percentage of sperm with normal morphology was significantly higher in winter (9.2%) than in summer and spring (7.0% and 7.5%, respectively; P <.05). The mean percentage of sperm with head defects was significantly higher in fall and summer (74.0% and 72.3%, respectively) than in winter (68.6%; P <.05). Seasonal variations were found in sperm concentration and morphology, with higher sperm concentrations in winter than in fall, and a greater percentage of sperm with normal morphology in winter than in spring and summer. Sperm concentration was lowest in the fall, whereas the percentage of sperm with normal morphology was lowest in summer. Semen volume, sperm concentration, total sperm count, motility, total motile sperm, and morphology decreased as age increased.

Adult↗

PubMedDate not supplied

The relationship between environmental exposure to phthalates and computer-aided sperm analysis motion parameters.

The general population is exposed to phthalates through consumer products, diet, and medical devices. The present study explored whether phthalates, reproductive toxins in laboratory animals, were associated with altered sperm movement characteristics in men. Two-hundred twenty subjects provided a semen sample for computer-aided sperm analysis (CASA) and a urine sample for measurement of phthalate monoesters, monoethyl (MEP), monobenzyl (MBzP), mono-n-butyl (MBP), mono-2-ethylhexyl (MEHP), and monomethyl (MMP). Three CASA parameters, straight-line velocity (VSL), curvilinear velocity (VCL), and linearity (LIN), were used as measures of sperm progression, sperm vigor, and swimming pattern, respectively. There were suggestive dose-response relationships (shown as the predicted change in mean sperm motion parameter for the second and third tertiles compared with the first tertile; P value for trend) for MBzP with VSL (-2.36 microm/s, -2.81 microm/s; P =.09) and VCL (-1.67 microm/s, -2.45 microm/s; P =.4). There were suggestive negative associations between MBP and VSL (-3.07 microm/s, -2.87 microm/s; P =.08) and VCL (-3.25 microm/s, -3.46 microm/s; P =.2), and between MEHP with VSL (-1.09 microm/s, -2.73 microm/s; P =.1) and VCL (-0.29 microm/s, -2.93 microm/s; P =.3). In contrast to the other phthalates, MEP was positively associated with VSL and VCL but negatively associated with LIN. No consistent relationship was found for MMP and any sperm motion parameter. Although we did not find statistically significant associations, trends between CASA parameters, sperm velocity, and forward progression, and increased urinary levels of MBP, MBzP, and MEHP warrant further follow-up.

Adult↗

PubMedDate not supplied

The relationship between human semen characteristics and sperm apoptosis: a pilot study.

This work was undertaken to explore the association between human semen characteristics and apoptosis in ejaculated sperm. We collected semen samples from 23 consecutive male patients who presented to the Andrology Laboratory at Massachusetts General Hospital (MGH) for routine semen analysis. Sperm concentration and motility were measured using computer-assisted sperm analysis. Morphology was assessed using Tygerberg strict criteria. The DNA diffusion assay was used to assess the percentage of apoptosis in ejaculated sperm. In this assay, cells were mixed with agarose and placed into a microgel on a microscopic slide. The cells were stained with YOYO-1 dye, and apoptotic cells were viewed under a fluorescent microscope. Among 23 men, the mean (SD) sperm concentration, percent motility, percent progressive motility, and normal morphology were 125.5 (92.3) million/mL, 45.6% (22.2), 28.4% (15.2), and 8.0 (4.6), respectively. The mean (SD) percent of apoptosis in ejaculated sperm was 8.3% (6.2) with a range from 1.1% to 20.1%. There were inverse associations between percent apoptosis and sperm motility (P = .0025), progressive motility (P = .0051), and morphology with a normal or good pattern of fertilization by Kruger strict criteria (P = .0045), and a positive relationship between percent apoptosis and sperm tail defects (P = .0053). In ejaculated semen, the percent sperm apoptosis was associated with several measures of semen quality.

Adult↗