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R Hauser

Publications and source records attributed to R Hauser.

At least 19 recordsLinked to original sources
PubMed2006

DNA damage in human sperm is related to urinary levels of phthalate monoester and oxidative metabolites.

BACKGROUND: The ubiquitous use of phthalate esters in plastics, personal care products and food packaging materials results in widespread general population exposure. In this report, we extend our preliminary study on the relationship between urinary concentrations of phthalate metabolites and sperm DNA damage among a larger sample of men and include measurements of mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), two oxidative metabolites of di-(2-ethylhexyl) phthalate (DEHP). METHODS: Among 379 men from an infertility clinic, urinary concentrations of phthalate metabolites were measured using isotope-dilution high-performance liquid chromatography-tandem mass spectrometry. Sperm DNA damage measurements, assessed with the neutral comet assay, included comet extent (CE), percentage of DNA in tail (Tail%) and tail distributed moment (TDM). RESULTS: Monoethyl phthalate (MEP), a metabolite of diethyl phthalate, was associated with increased DNA damage, confirming our previous findings. Mono-(2-ethylhexyl) phthalate (MEHP), a metabolite of DEHP, was associated with DNA damage after adjustment for the oxidative DEHP metabolites. After adjustment for MEHHP, for an interquartile range increase in urinary MEHP, CE increased 17.3% [95% confidence interval (CI) = 8.7-25.7%], TDM increased 14.3% (95% CI = 6.8-21.7%) and Tail% increased 17.5% (95% CI = 3.5-31.5%). CONCLUSIONS: Sperm DNA damage was associated with MEP and with MEHP after adjusting for DEHP oxidative metabolites, which may serve as phenotypic markers of DEHP metabolism to 'less toxic' metabolites. The urinary levels of phthalate metabolites among these men were similar to those reported for the US general population, suggesting that exposure to some phthalates may affect the population distribution of sperm DNA damage.

Adult↗
PubMed2006

Maternal exposure to second-hand tobacco smoke and pregnancy outcome among couples undergoing assisted reproduction.

BACKGROUND: Exposure to second-hand tobacco smoke is preventable, yet common. This study assessed relationships between maternal exposure to second-hand tobacco smoke and adverse pregnancy outcomes. METHODS: We measured cotinine (a biomarker of tobacco smoke) in urine from 921 women undergoing assisted reproductive technologies (ARTs) between 1994 and 1998. We also collected information on self-reported exposure to second-hand smoke at home or at work, in addition to parental smoking during the women's childhood. RESULTS: In crude analysis, creatinine-adjusted cotinine levels were associated with a slight decrease in implantation rate among non-smoking women (11.1% in the lowest cotinine quintile versus 8.2% in the highest cotinine quintile; P=0.13). However, in multivariate logistic regression, cotinine levels above the median were not associated with failed fertilization, failed implantation or spontaneous abortion, nor was there evidence of a dose-response relationship among cotinine quintiles. After excluding women in couples diagnosed with male factor infertility, there were increased odds of having a spontaneous abortion among non-smoking women who reported that both parents smoked while they were children growing up compared with women reporting that neither parent smoked [adjusted odds ratio (OR) = 4.35; 95% confidence interval (CI) = 1.04-18.1]. CONCLUSIONS: Female exposure to second-hand smoke as a child or in utero may be associated with an increased risk of spontaneous abortion in adulthood. However, this may be a chance finding due to multiple comparisons. Similar associations should be explored in additional studies with more refined estimates of childhood and in utero exposure to tobacco smoke.

Abortion, Spontaneous↗
PubMed2006

Expression profile of AZF genes in testicular biopsies of azoospermic men.

BACKGROUND: The Y-chromosome AZF regions include genes whose functions and specific roles in spermatogenesis have not been fully clarified. This study investigated the expression of several AZF (USP9Y, DDX3Y/DDX3Yt1, EIF1AY and PRY) and USP9X transcripts in testicular biopsies of 89 azoospermic men who had been classified by histology and cytology assessments. METHODS: Expression was analysed by RT-PCR, and some biopsies were evaluated by multiplex RT-PCR. Quantitative PCR was performed in some biopsies to determine the ratio of the testis-specific transcript DDX3Yt1 to the total DDX3Y transcription. RESULTS: The expression of USP9Y, USP9X and DDX3Y was found in all the specimens tested, whereas DDX3Yt1 expression was diminished or undetectable in several biopsies with impaired spermatogenesis. EIF1AY was detected in all except two of the specimens. Noteworthy, PRY expression was detected mainly in biopsies with germ cells, and this association was significant (P < 0.001). An identical expression profile was obtained by either single or multiplex RT-PCR. CONCLUSIONS: These findings suggest that PRY is usually expressed in germ cells, whereas the other transcripts are also expressed in testicular somatic cells. The absence of EIF1AY expression might sporadically contribute to azoospermia. The decreased ratio of DDX3Yt1/DDX3Y transcript in impaired spermatogenesis suggests that the DDX3Yt1 transcript is under-expressed in impaired spermatogenesis. The findings contribute to the search and selection of the most valuable gene markers potentially useful as additional tools for predicting complete spermatogenesis by multiplex expression analysis.

Azoospermia↗
PubMed2006

Development of a Patient Questionnaire to facilitate recognition of motor and non-motor wearing-off in Parkinson's disease.

We previously reported that the use of a specifically designed Wearing-Off Questionnaire (WOQ) identified symptoms of wearing-off more frequently than standard assessments conducted by movement disorder specialists during a routine office visit. In the previous study we used a WOQ of 32 symptoms; however this tool was not designed for daily use. In this paper we describe the retrospective development of a simpler, 19-symptom WOQ more suitable for routine clinical use.

Aged↗
PubMed2006

Milk cortisol concentration in automatic milking systems compared with auto-tandem milking parlors.

Milk cortisol concentration was determined under routine management conditions on 4 farms with an auto-tandem milking parlor and 8 farms with 1 of 2 automatic milking systems (AMS). One of the AMS was a partially forced (AMSp) system, and the other was a free cow traffic (AMSf) system. Milk samples were collected for all the cows on a given farm (20 to 54 cows) for at least 1 d. Behavioral observations were made during the milking process for a subset of 16 to 20 cows per farm. Milk cortisol concentration was evaluated by milking system, time of day, behavior during milking, daily milk yield, and somatic cell count using linear mixed-effects models. Milk cortisol did not differ between systems (AMSp: 1.15 +/- 0.07; AMSf: 1.02 +/- 0.12; auto-tandem parlor: 1.01 +/- 0.16 nmol/L). Cortisol concentrations were lower in evening than in morning milkings (1.01 +/- 0.12 vs. 1.24 +/- 0.13 nmol/L). The daily periodicity of cortisol concentration was characterized by an early morning peak and a late afternoon elevation in AMSp. A bimodal pattern was not evident in AMSf. Finally, milk cortisol decreased by a factor of 0.915 in milking parlors, by 0.998 in AMSp, and increased by a factor of 1.161 in AMSf for each unit of ln(somatic cell count/1,000). We conclude that milking cows in milking parlors or AMS does not result in relevant stress differences as measured by milk cortisol concentrations. The biological relevance of the difference regarding the daily periodicity of milk cortisol concentrations observed between the AMSp and AMSf needs further investigation.

Animals↗
PubMed2004

Seasonal variations in pre- and post-thaw donor sperm quality.

BACKGROUND: The present study was conducted to evaluate seasonal variability in the quality of pre- and post-thaw semen parameters among sperm bank donors. METHODS: The first two consecutive ejaculates during the months March (spring, 92 males), June (summer, 97 males), September (autumn, 81 males) and December (winter, 97 males) were analysed. A comparison was made between sperm parameters from the same sperm donor at different seasons. Only males who donated semen samples during at least two seasons were enrolled in the study group (n = 103). Sperm specimens were cryopreserved in aliquots with fixed range of 8-12 x 10(6)/ml of progressive motile sperm concentration after thawing. RESULTS: Differences between months were found in sperm concentration (P = 0.030) and normal morphology (P = 0.038); highest values were found in March and December, and the lowest in September. Mean specimen volume and percent of motile sperm cells did not vary throughout the seasons. The freezability of the donors' sperm dropped dramatically from March to September, as determined by the number of straws (fixed aliquots of 0.5 ml) and total thawed progressive motile sperm that were cryopreserved for each male (P = 0.017 and P = 0.002, respectively). CONCLUSIONS: Cryopreservation of donor sperm is more effective during winter and spring than during the rest of the year.

Adult↗
PubMed2004

A case-crossover study of transient risk factors for occupational acute hand injury.

BACKGROUND: Workers with acute hand injuries account for over 1 000 000 emergency department visits annually in the United States. AIMS: To determine potential transient risk factors for occupational acute hand injury. METHODS: Subjects were recruited from 23 occupational health clinics in five northeastern states in the USA. In a telephone interview, subjects were asked to report the occurrence of seven potential risk factors within a 90-minute time period before an acute hand injury. Each case also provided control information on exposures during the month before the injury. The self-matched feature of the study design controlled for stable between-person confounders. RESULTS: A total of 1166 subjects were interviewed (891 men, 275 women), with a mean age (SD) of 37.2 years (11.4). The median time interval between injury and interview was 1.3 days. Sixty three per cent of subjects had a laceration. The relative risk of a hand injury was increased when working with equipment, tools, or work pieces not performing as expected (11.0, 95% CI 9.4 to 12.8), or when using a different work method to do a task (10.5, 95% CI 8.7 to 12.7). Other transient factors in decreasing order of relative risk were doing an unusual task, being distracted, and being rushed. Wearing gloves reduced the relative risk by 60% (0.4, 95% CI 0.3 to 0.5). Occupational category, job experience, and safety training were found to alter several of these effects. CONCLUSION: The results suggest the importance of these transient, potentially modifiable factors in the aetiology of acute hand injury at work. Attempts to modify these exposures by various strategies may reduce the incidence of acute hand injury at work.

Accidents, Occupational↗
PubMed2003

Lack of an association between environmental exposure to polychlorinated biphenyls and p,p'-DDE and DNA damage in human sperm measured using the neutral comet assay.

BACKGROUND: Chlorinated organic chemicals, such as polychlorinated biphenyls (PCB), hexachlorobenzene (HCB), dichlorodiphenyl trichloroethane (DDT), and dichlorodiphenyl dichloroethene (DDE, the most stable daughter compound of DDT) are persistent lipophilic compounds found in a large portion of the general population. To explore the hypothesis that environmental exposure to these compounds is associated with altered DNA integrity in human sperm, a study of 212 male partners of a sub-fertile couple who presented to the Massachusetts General Hospital Andrology Laboratory was conducted. METHODS: The neutral single cell microgel electrophoresis assay (comet assay) was used to assess DNA integrity in sperm. VisComet image analysis software was used to measure total comet length, the proportion of DNA present in the comet tail, and tail distributed moment, an integrated measure of length and intensity. RESULTS: In the regression analyses, there were no statistically significant consistent associations between the comet assay parameters and any of the individual PCB congeners, sum of PCB, or p,p'-DDE. CONCLUSION: These results suggest that there are not strong relationships between adult levels of these chlorinated organic compounds and sperm DNA damage as measured by the comet assay.

Adult↗
PubMed2002

[Epidemiological basis and results of the National Survey 2001 conducted in the Swiss pig population].

Free trade with animals and animal products requires transparency concerning health information of animal populations. On the basis of the bilateral agreement with the European Union (EU), Switzerland is obliged to document freedom from Aujeszky's disease (AD) in its pig population by conducting surveys on a regular basis. Such a survey was planned for the first time for the year 2001. In this context, it was evaluated whether additional pig diseases should be included in the survey. This article describes the evaluation procedure for the selection of pig diseases integrated in the survey 2001. Additionally, it reports and interprets the results of this survey. All of the 2537 farms and 41,719 blood samples were tested negative. Therefore, it could be documented with a confidence of 99.98% that the AD-prevalence in Switzerland is below 1%.

Animals↗
PubMed2002

Reliability of the comet assay in cryopreserved human sperm.

BACKGROUND: Although the comet assay has potential value for measuring DNA damage in large epidemiological human sperm studies, it is impractical to perform the assay daily on fresh semen samples. Therefore, before its use in epidemiological studies, the reliability of the comet assay in measuring DNA damage in cryopreserved sperm should be compared with that in fresh human sperm. METHODS: Semen samples from 16 men were cryopreserved in liquid nitrogen (LN) using four methods: flash freezing with and without cryopreservative, and programmable freezing with and without cryopreservative. Neutral microgel electrophoresis was performed and comets were stained with YOYO-1. Comet length was measured using an eyepiece micrometer at x400 magnification. RESULTS: The highest correlation was between comet assay results obtained from fresh human semen compared with semen flash frozen without cryopreservative (R = 0.88). However, the method of cryopreservation, as compared with other sources of variability, accounted for only 6% of the variability. Inter-individual variability accounted for 20%, and individual sperm-to-sperm variability within an ejaculate accounted for 65%. CONCLUSIONS: Flash-freezing in LN without cryopreservative most closely reproduced the results obtained using fresh human semen samples, and thereby represents the most appropriate cryopreservation method for human semen in epidemiological studies utilizing the neutral comet assay.

Adult↗
PubMed2002

Regional distribution of glutamate in the central nervous system of rat terminated by carbon dioxide euthanasia.

Carbon dioxide euthanasia is an established method for the termination of small laboratory animals. It has also been employed by the authors in neurobiological research on the post-mortem glutamate concentration in the structures of rat brains. The following investigations were aimed at optimizing the termination procedure based on the CO2 saturation rate of the inhaled air. Two rates of CO2 flow were applied, and the higher one significantly augmented the glutamate level in the hippocampus and cerebellum. The relationship between this finding and signs of central fear reaction is discussed. The authors conclude that lower rather than higher CO2 flow in euthanasia procedures is gentler and is therefore preferable for use with laboratory animals.

Animals↗
PubMed2001

Haemorrhages in head tissues during the asphyxiation process.

Two rates of carbon dioxide flow into the termination chamber were applied for the euthanasia of rats. The classical phases of asphyxia were observed in both groups of animals although their course was prolonged in rats exposed to the lower gas flow. The haemorrhages were assessed histologically in the following structures: the pericranium, compact bone and diploë of the skull, sagittal suture, nape muscle and its attachment, and the dura. The haemorrhages appeared regularly in the sagittal suture in all cases from both experimental groups. The possible significance of this phenomenon for the forensic practice was pointed out.

Animals↗
PubMed2001

The post-mortem concentration of glutamate in the structures of rat brain as an exponent of short aversive sensory stimulation preceding death.

The problem of post-mortem assessment of short central fear reaction preceding death has been obscure till now. The preliminary results obtained by authors have encouraged them to further research on this topic. Time of aversive sensory stimulation in the presented study was considerably decreased in comparison to the preliminary investigations. The concentration of glutamate was assayed in the selected structures of limbic system and in the cerebellum. The rats were subjected to different simultaneous modalities of sensory stimulation. The involvement of the hippocampi and the cerebellum was revealed as measured by glutamate concentration increase in the whole structures homogenates. The dominant role of mechanical stimulus has been suggested based on the measured increase of glutamate concentration in the whole cerebellum homogenate. By using the presented experimental paradigm a possible application of the biochemical assessment of human brain tissue might be developed in the future for implementing in the field of forensic pathology. The biochemical evaluation of "frozen frames" of neurotransmission can possibly help reconstruct the events which had happened just before sudden and violent death.

Acoustic Stimulation↗
PubMed2001

Differential ability of transition metals to induce pulmonary inflammation.

Transition metals are components of airborne particles and have been implicated in adverse health effects. The relative inflammatory potential of these metals is usually inferred from separate studies that focus on only one or a few individual metals. Comparisons of relative potency among several metals from these separate studies can be difficult. In one comprehensive study, we measured the pulmonary effects of equimolar doses of six metals in soluble form. Our purpose was to compare inflammatory potential and pulmonary toxicity among individual transition metals. Rats received saline, 0.1 or 1.0 micromol/kg of vanadium, nickel, iron(II), copper, manganese, or zinc as sulfates. Bronchoalveolar lavage (BAL) was performed at 0, 4, 16, or 48 h postinstillation. All treatments except V showed increased lactate dehydrogenase activity in BAL fluid; Cu- and Ni-exposed animals had the highest levels. Protein levels in BAL fluid were more than five times higher in Cu-exposed animals compared to other metal treatments at 16 and 48 h. At the 0.1 micromol/kg dose, only Cu induced significant neutrophilia at 16 and 48 h. For the 1.0 micromol/kg dose, all metals tested induced significant neutrophilia, with mean neutrophil numbers for Cu and Mn significantly higher compared to the other metals. At 48 h, neutrophil numbers were still elevated in all metal exposures. Only Mn caused substantial eosinophilia. At the 1.0 micromol/kg dose, only Cu induced macrophage inflammatory protein-2 (MIP-2) mRNA at 4 h. By 48 h, induction of MIP-2 mRNA was observed for all metal exposures except Cu, which subsequently returned to baseline levels. On an equimolar basis, Cu was the most proinflammatory metal, followed by Mn and Ni, while V, Fe(II), and Zn induced similar levels of inflammation. Overall, there were many similarities in the pulmonary responses of the metals we tested. However, we also observed divergent, metal-specific responses. These differential responses suggest that metals induce pulmonary inflammation by differing pathways or combinations of signals.

Actins↗
PubMed2001

Association of heart rate variability with occupational and environmental exposure to particulate air pollution.

BACKGROUND: Airborne particulate matter has been linked to excess morbidity and mortality. Recent attention has focused on the effects of particulate exposure on cardiac autonomic control. Inhaled particulates may affect the autonomic nervous system either directly, by eliciting a sympathetic stress response, or indirectly, through inflammatory cytokines produced in the lungs and released into the circulation. METHODS AND RESULTS: This longitudinal study examined the association of particulates </=2.5 microm in diameter (PM(2.5)) with heart rate variability (HRV) in an occupational cohort (N=40). Continuous monitoring of exposure and HR was performed during and away from work. PM(2.5) levels were higher than ambient levels typically reported in Boston, 0.167+/-3.205 mg/m(3) (geometric mean+/-geometric SD). We found a 2.66% decrease (95% CI, -3.75% to -1.58%) in the 5-minute SD of normal RR intervals (SDNN) for every 1 mg/m(3) increase in the 4-hour moving PM(2.5) average and a 1.02% increase (95% CI, 0.59% to 1.46%) in HR after adjusting for potential confounding factors. The decrease in SDNN became larger as the averaging interval increased. CONCLUSIONS: Workers experienced altered cardiac autonomic control after exposure to occupational and environmental PM(2.5). There appears to be either a long-acting (several hours) and a short-acting (several minutes) component to the mechanism of action that may be related to the production of cytokines and the sympathetic stress response, respectively, or a cumulative effect that begins shortly after exposure begins. The clinical significance of these effects in a healthy working population is unclear.

Adult↗
PubMed2001

Stochastic modelling as a tool for planning animal-health surveys and interpreting screening-test results.

Traditionally, the planning of surveys (in particular, sample-size calculations) has relied on assumptions including the assumption of perfect screening tests. This paper presents a novel approach that can be used for planning animal-health surveys and interpreting screening-test results in the context of these surveys. A stochastic simulation model developed to assess the properties of herd-level sampling schemes and surveys has been adapted for large surveys aimed at substantiating freedom from infection at a national or regional level. We use a Bayesian approach to derive the post-survey probability of freedom from infection from the pre-survey probability of freedom and the likelihood ratio that is associated with screening-test results. We applied the model to two consecutive surveys conducted in 1998 and 1999 in Switzerland to substantiate freedom from infectious bovine rhinotracheitis (IBR) in the cattle population of about 56000 herds (median herd size of 15 cattle > 2 yr of age in 1999). In 1998, serum samples were taken from five cattle > 2 yr in 4672 herds, and in 1999 from all cattle > 2 yr old in 648 herds; samples were analysed by ELISA. The survey of 1999 provided less evidence than that of 1998 to support a status of freedom from infection; also, the characteristics of both herd-level sampling schemes were similar. We argue that the rationale for survey planning depends on the pre-survey probability of freedom from infection (i.e. our level of confidence that the infection does not occur in the targeted animal population). In consequence, surveys should be tailored to individual populations in the respective countries or regions. The model has been developed in an Excel spreadsheet to allow flexibility of use, and adaptation to many other animal-health issues.

Animals↗