Andrew Wyrobek | Lawrence Berkeley National Laboratory (original) (raw)
Papers by Andrew Wyrobek
PubMed, Mar 1, 1997
We investigated the relationship between psychological stress and sperm concentration, motility, ... more We investigated the relationship between psychological stress and sperm concentration, motility, and morphometry in a prospective study of 157 volunteers who were enrolled in a prepaid health plan. We measured psychological job stress and life-event stress by telephone interview. Sperm-kinematic and nuclear-morphometric variables were measured using computer-assisted image analyses. Sperm concentration, percent motility, and semen volume were determined by objective visual methods. We performed multiple linear regression for each semen variable to examine its relationship to stress, controlling for potential confounders. Stress at work and total number of life events were not related to differences in semen quality. However, the recent death of a close family member was associated with a reduction in straight-line velocity (P = 0.002) and percent of progressively motile sperm (P = 0.02); it was also marginally associated with an increase in the fraction of sperm with larger and more tapered nuclei. These findings suggest that the fecundity of men experiencing the stress of a family member's death might be temporarily diminished.
Anesthesiology, Sep 1, 1982
Environmental Health Perspectives, Feb 1, 1983
Reproductive Toxicology, 1993
Laboratory investigation; a journal of technical methods and pathology, 2018
A variety of laboratory methods are available for the detection of deletions of tumor suppressor ... more A variety of laboratory methods are available for the detection of deletions of tumor suppressor genes and losses of their proteins. The clinical utility of fluorescence in situ hybridization (FISH) for the identification of deletions of tumor suppressor genes has previously been limited by difficulties in the interpretation of FISH signal patterns. The first deletion FISH assays using formalin-fixed paraffin-embedded tissue sections had to deal with a significant background level of signal losses affecting nuclei that are truncated by the cutting process of slide preparation. Recently, more efficient probe designs, incorporating probes adjacent to the tumor suppressor gene of interest, have increased the accuracy of FISH deletion assays so that true chromosomal deletions can be readily distinguished from the false signal losses caused by sectioning artifacts. This mini-review discusses the importance of recurrent tumor suppressor gene deletions in human cancer and reviews the commo...
Environmental and Molecular Mutagenesis, 1998
A multicolor fluorescence in situ hybridization (FISH) method was developed to detect aneuploidy ... more A multicolor fluorescence in situ hybridization (FISH) method was developed to detect aneuploidy and diploidy in epididymal sperm of rats using DNA probes specific for chromosomes 4 and Y. Fourteen healthy young-adult rats from three strains were evaluated: inbred Fisher 344/N/ehs, outbred Sprague-Dawley, and outbred WU Wistar/CPB. The hybridization efficiency of the FISH procedure was > 99.9%, the sex-ratio in sperm was approximately 1 as expected, and there was no significant variation among two independent scorers. No significant variations were detected within or among strains in the frequencies of sperm disomy for chromosome 4 (1-6.5 per 10,000 cell per animal) or the Y chromosome (0-2.5 per 10,000 cells per animal). There was a trend toward increased variation among Wistar rats. The frequencies of sperm-carrying hyper- and hypohaploidy for chromosome 4 were similar, suggesting a symmetrical mechanism of chromosome gain and loss during meiosis. The frequencies of Y-Y-4-4 sperm, which represent genomic meiosis II errors, did not differ significantly across strains (0.1-0.7 per 10,000 cells per strain). This FISH method for detecting aneuploidy in rat epididymal sperm provides a promising interspecies biomarker of male germ cell aneuploidy and introduces the rat as an animal model for investigating the heritable risk to offspring associated with paternal genotype, physiology, and exposure to environmental mutagens. There appear to be no significant differences among young healthy rats, mice, and men in the baseline frequencies of sperm with Y chromosomal disomy, the only chromosome for which data currently exists for all three species.
Environmental and Molecular Mutagenesis, 1996
A 2 1/2-day workshop on germ cell aneuploidy was convened September 11-13, 1995 at the National I... more A 2 1/2-day workshop on germ cell aneuploidy was convened September 11-13, 1995 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina to discuss current understandings of the etiology and origin of human aneuploidy, especially in regard to potential environmental causes, and to identify gaps in our research knowledge. The workshop was designed to facilitate interactions among research experts conducting studies on the fundamental biology of chromosomal movement and segregation, on aneuploidy as a human clinical problem, and on toxicological aspects of aneuploidy induction. Overview presentations provided perspectives on aneuploidy as a human clinical problem, the genetics of aneuploidy, and the issues of concern in toxicological testing and regulatory risk assessment. The four chairs introduced the topics for each of their workgroups, setting the stage for subsequent, in-depth discussions on (1) chromosome mover components, (2) altered recombination, (3) parental age effects, and (4) differential chromosome susceptibility. From these discussions, gaps in our research knowledge related to the role of the environment in the etiology of aneuploidy and associated molecular, cellular, and genetic processes involved were identified, and will be used to establish a research agenda for filling those gaps.
Biology of Reproduction, Oct 1, 1999
Protein isoforms produced by alternative splicing (AS) of many genes have been implicated in seve... more Protein isoforms produced by alternative splicing (AS) of many genes have been implicated in several aspects of cancer genesis and progression. These observations motivated a genome-wide assessment of AS in breast cancer. We accomplished this by measuring exon level expression in 31 breast cancer and nonmalignant immortalized cell lines representing luminal, basal, and claudin-low breast cancer subtypes using Affymetrix Human Junction Arrays. We analyzed these data using a computational pipeline specifically designed to detect AS with a low false-positive rate. This identified 181 splice events representing 156 genes as candidates for AS. Reverse transcription-PCR validation of a subset of predicted AS events confirmed 90%. Approximately half of the AS events were associated with basal, luminal, or claudin-low breast cancer subtypes. Exons involved in claudin-low subtype–specific AS were significantly associated with the presence of evolutionarily conserved binding motifs for the tissue-specific Fox2 splicing factor. Small interfering RNA knockdown of Fox2 confirmed the involvement of this splicing factor in subtype-specific AS. The subtype-specific AS detected in this study likely reflects the splicing pattern in the breast cancer progenitor cells in which the tumor arose and suggests the utility of assays for Fox-mediated AS in cancer subtype definition and early detection. These data also suggest the possibility of reducing the toxicity of protein-targeted breast cancer treatments by targeting protein isoforms that are not present in limiting normal tissues. Mol Cancer Res; 8(7); 961–74. ©2010 AACR.
Proceedings of the National Academy of Sciences of the United States of America, Oct 23, 2002
Lawrence Berkeley National Laboratory, Jul 27, 2009
Humana Press eBooks, 2008
Neurotoxicology, Mar 1, 2009
Fertility and Sterility, Jul 1, 1988
A quantitative, semi-automated method for classifying human sperm based on objective measurements... more A quantitative, semi-automated method for classifying human sperm based on objective measurements of head shapes and sizes has been developed. Air-dried smears of semen from eight healthy men were stained with the Feulgen reaction and 283 sperm were selected as prototypic examples of the 10 morphology classes used in our classification system. Sperm heads were imaged through a microscope (NA = 1.3), sampled at 0.125-micron intervals, and measured on an image analysis system. Measurements included stain content, length, width, perimeter, area, and arithmetically derived combinations. Additionally, each sperm image was optically sectioned at right angles to its major axis to give a measure of lengthwise heterogeneity of shape. Linear stepwise discriminant analysis was used to identify the more powerful parameters and to create a model employing eight parameters. The jackknifed classification procedure distinguished normal from abnormal sperm with 95% accuracy and correctly assigned 86% of the sperm to one of 10 shape classes. Most of the misclassification errors occurred among closely related classes. The results demonstrate the ability of automated image analysis to classify individual sperm into clinically familiar shape categories.
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Aug 31, 2021
Environmental and Molecular Mutagenesis, Dec 31, 1994
Three-chromosome fluorescence in situ hybridization (FISH) was applied to sperm of men with Hodgk... more Three-chromosome fluorescence in situ hybridization (FISH) was applied to sperm of men with Hodgkin`s disease to measure the persistence of chromosomally abnormal sperm within the time interval of 3 to 33 months after the end of treatment. NOVP chemotherapy includes the agents novantrone, oncovin, vinblastine, and prednisone, two of which are spindle poisons expected to induce aneuploidy. Semen samples were evaluated for the frequencies of fluorescence phenotypes representing hyperhaploidy, hypohaploidy, and genomic duplications using DNA probes specific for repetitive sequences on chromosomes X,Y, and 8. Using this procedure, NOVP was previously shown to induce chromosomally abnormal sperm in treated patients. In a longitudinal assessment of 11 semen samples from 2 men, frequencies of abnormal sperm appeared to return to pre-treatment levels at {approximately}6 months after the end of treatment and remained at these levels up to 33 months after the end of treatment. However, pre-treatment frequencies of chromosomally abnormal cells in Hodgkin`s patients were elevated above those found in normal healthy men. Additional patients are being evaluated to determine how long after therapy Hodgkin`s disease patients remain at increased risk for producing chromosomally abnormal sperm.
![Research paper thumbnail of Human semen assays for workplace monitoring. [Monitoring of hazardous materials by determining effects on semen of personnel]](https://attachments.academia-assets.com/107044893/thumbnails/1.jpg)
](OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Nov 7, 1978
PubMed, Mar 1, 1997
We investigated the relationship between psychological stress and sperm concentration, motility, ... more We investigated the relationship between psychological stress and sperm concentration, motility, and morphometry in a prospective study of 157 volunteers who were enrolled in a prepaid health plan. We measured psychological job stress and life-event stress by telephone interview. Sperm-kinematic and nuclear-morphometric variables were measured using computer-assisted image analyses. Sperm concentration, percent motility, and semen volume were determined by objective visual methods. We performed multiple linear regression for each semen variable to examine its relationship to stress, controlling for potential confounders. Stress at work and total number of life events were not related to differences in semen quality. However, the recent death of a close family member was associated with a reduction in straight-line velocity (P = 0.002) and percent of progressively motile sperm (P = 0.02); it was also marginally associated with an increase in the fraction of sperm with larger and more tapered nuclei. These findings suggest that the fecundity of men experiencing the stress of a family member's death might be temporarily diminished.
Anesthesiology, Sep 1, 1982
Environmental Health Perspectives, Feb 1, 1983
Reproductive Toxicology, 1993
Laboratory investigation; a journal of technical methods and pathology, 2018
A variety of laboratory methods are available for the detection of deletions of tumor suppressor ... more A variety of laboratory methods are available for the detection of deletions of tumor suppressor genes and losses of their proteins. The clinical utility of fluorescence in situ hybridization (FISH) for the identification of deletions of tumor suppressor genes has previously been limited by difficulties in the interpretation of FISH signal patterns. The first deletion FISH assays using formalin-fixed paraffin-embedded tissue sections had to deal with a significant background level of signal losses affecting nuclei that are truncated by the cutting process of slide preparation. Recently, more efficient probe designs, incorporating probes adjacent to the tumor suppressor gene of interest, have increased the accuracy of FISH deletion assays so that true chromosomal deletions can be readily distinguished from the false signal losses caused by sectioning artifacts. This mini-review discusses the importance of recurrent tumor suppressor gene deletions in human cancer and reviews the commo...
Environmental and Molecular Mutagenesis, 1998
A multicolor fluorescence in situ hybridization (FISH) method was developed to detect aneuploidy ... more A multicolor fluorescence in situ hybridization (FISH) method was developed to detect aneuploidy and diploidy in epididymal sperm of rats using DNA probes specific for chromosomes 4 and Y. Fourteen healthy young-adult rats from three strains were evaluated: inbred Fisher 344/N/ehs, outbred Sprague-Dawley, and outbred WU Wistar/CPB. The hybridization efficiency of the FISH procedure was > 99.9%, the sex-ratio in sperm was approximately 1 as expected, and there was no significant variation among two independent scorers. No significant variations were detected within or among strains in the frequencies of sperm disomy for chromosome 4 (1-6.5 per 10,000 cell per animal) or the Y chromosome (0-2.5 per 10,000 cells per animal). There was a trend toward increased variation among Wistar rats. The frequencies of sperm-carrying hyper- and hypohaploidy for chromosome 4 were similar, suggesting a symmetrical mechanism of chromosome gain and loss during meiosis. The frequencies of Y-Y-4-4 sperm, which represent genomic meiosis II errors, did not differ significantly across strains (0.1-0.7 per 10,000 cells per strain). This FISH method for detecting aneuploidy in rat epididymal sperm provides a promising interspecies biomarker of male germ cell aneuploidy and introduces the rat as an animal model for investigating the heritable risk to offspring associated with paternal genotype, physiology, and exposure to environmental mutagens. There appear to be no significant differences among young healthy rats, mice, and men in the baseline frequencies of sperm with Y chromosomal disomy, the only chromosome for which data currently exists for all three species.
Environmental and Molecular Mutagenesis, 1996
A 2 1/2-day workshop on germ cell aneuploidy was convened September 11-13, 1995 at the National I... more A 2 1/2-day workshop on germ cell aneuploidy was convened September 11-13, 1995 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina to discuss current understandings of the etiology and origin of human aneuploidy, especially in regard to potential environmental causes, and to identify gaps in our research knowledge. The workshop was designed to facilitate interactions among research experts conducting studies on the fundamental biology of chromosomal movement and segregation, on aneuploidy as a human clinical problem, and on toxicological aspects of aneuploidy induction. Overview presentations provided perspectives on aneuploidy as a human clinical problem, the genetics of aneuploidy, and the issues of concern in toxicological testing and regulatory risk assessment. The four chairs introduced the topics for each of their workgroups, setting the stage for subsequent, in-depth discussions on (1) chromosome mover components, (2) altered recombination, (3) parental age effects, and (4) differential chromosome susceptibility. From these discussions, gaps in our research knowledge related to the role of the environment in the etiology of aneuploidy and associated molecular, cellular, and genetic processes involved were identified, and will be used to establish a research agenda for filling those gaps.
Biology of Reproduction, Oct 1, 1999
Protein isoforms produced by alternative splicing (AS) of many genes have been implicated in seve... more Protein isoforms produced by alternative splicing (AS) of many genes have been implicated in several aspects of cancer genesis and progression. These observations motivated a genome-wide assessment of AS in breast cancer. We accomplished this by measuring exon level expression in 31 breast cancer and nonmalignant immortalized cell lines representing luminal, basal, and claudin-low breast cancer subtypes using Affymetrix Human Junction Arrays. We analyzed these data using a computational pipeline specifically designed to detect AS with a low false-positive rate. This identified 181 splice events representing 156 genes as candidates for AS. Reverse transcription-PCR validation of a subset of predicted AS events confirmed 90%. Approximately half of the AS events were associated with basal, luminal, or claudin-low breast cancer subtypes. Exons involved in claudin-low subtype–specific AS were significantly associated with the presence of evolutionarily conserved binding motifs for the tissue-specific Fox2 splicing factor. Small interfering RNA knockdown of Fox2 confirmed the involvement of this splicing factor in subtype-specific AS. The subtype-specific AS detected in this study likely reflects the splicing pattern in the breast cancer progenitor cells in which the tumor arose and suggests the utility of assays for Fox-mediated AS in cancer subtype definition and early detection. These data also suggest the possibility of reducing the toxicity of protein-targeted breast cancer treatments by targeting protein isoforms that are not present in limiting normal tissues. Mol Cancer Res; 8(7); 961–74. ©2010 AACR.
Proceedings of the National Academy of Sciences of the United States of America, Oct 23, 2002
Lawrence Berkeley National Laboratory, Jul 27, 2009
Humana Press eBooks, 2008
Neurotoxicology, Mar 1, 2009
Fertility and Sterility, Jul 1, 1988
A quantitative, semi-automated method for classifying human sperm based on objective measurements... more A quantitative, semi-automated method for classifying human sperm based on objective measurements of head shapes and sizes has been developed. Air-dried smears of semen from eight healthy men were stained with the Feulgen reaction and 283 sperm were selected as prototypic examples of the 10 morphology classes used in our classification system. Sperm heads were imaged through a microscope (NA = 1.3), sampled at 0.125-micron intervals, and measured on an image analysis system. Measurements included stain content, length, width, perimeter, area, and arithmetically derived combinations. Additionally, each sperm image was optically sectioned at right angles to its major axis to give a measure of lengthwise heterogeneity of shape. Linear stepwise discriminant analysis was used to identify the more powerful parameters and to create a model employing eight parameters. The jackknifed classification procedure distinguished normal from abnormal sperm with 95% accuracy and correctly assigned 86% of the sperm to one of 10 shape classes. Most of the misclassification errors occurred among closely related classes. The results demonstrate the ability of automated image analysis to classify individual sperm into clinically familiar shape categories.
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Aug 31, 2021
Environmental and Molecular Mutagenesis, Dec 31, 1994
Three-chromosome fluorescence in situ hybridization (FISH) was applied to sperm of men with Hodgk... more Three-chromosome fluorescence in situ hybridization (FISH) was applied to sperm of men with Hodgkin`s disease to measure the persistence of chromosomally abnormal sperm within the time interval of 3 to 33 months after the end of treatment. NOVP chemotherapy includes the agents novantrone, oncovin, vinblastine, and prednisone, two of which are spindle poisons expected to induce aneuploidy. Semen samples were evaluated for the frequencies of fluorescence phenotypes representing hyperhaploidy, hypohaploidy, and genomic duplications using DNA probes specific for repetitive sequences on chromosomes X,Y, and 8. Using this procedure, NOVP was previously shown to induce chromosomally abnormal sperm in treated patients. In a longitudinal assessment of 11 semen samples from 2 men, frequencies of abnormal sperm appeared to return to pre-treatment levels at {approximately}6 months after the end of treatment and remained at these levels up to 33 months after the end of treatment. However, pre-treatment frequencies of chromosomally abnormal cells in Hodgkin`s patients were elevated above those found in normal healthy men. Additional patients are being evaluated to determine how long after therapy Hodgkin`s disease patients remain at increased risk for producing chromosomally abnormal sperm.
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Nov 7, 1978