567 research outputs found
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
Predicting live birth, preterm and low birth weight infant after in-vitro fertilisation: a prospective study of 144018 treatment cycles
Background
The extent to which baseline couple characteristics affect the probability of live birth and adverse perinatal outcomes after assisted conception is unknown.
Methods and Findings
We utilised the Human Fertilisation and Embryology Authority database to examine the predictors of live birth in all in vitro fertilisation (IVF) cycles undertaken in the UK between 2003 and 2007 (n = 144,018). We examined the potential clinical utility of a validated model that pre-dated the introduction of intracytoplasmic sperm injection (ICSI) as compared to a novel model. For those treatment cycles that resulted in a live singleton birth (n = 24,226), we determined the associates of potential risk factors with preterm birth, low birth weight, and macrosomia. The overall rate of at least one live birth was 23.4 per 100 cycles (95% confidence interval [CI] 23.2–23.7). In multivariable models the odds of at least one live birth decreased with increasing maternal age, increasing duration of infertility, a greater number of previously unsuccessful IVF treatments, use of own oocytes, necessity for a second or third treatment cycle, or if it was not unexplained infertility. The association of own versus donor oocyte with reduced odds of live birth strengthened with increasing age of the mother. A previous IVF live birth increased the odds of future success (OR 1.58, 95% CI 1.46–1.71) more than that of a previous spontaneous live birth (OR 1.19, 95% CI 0.99–1.24); p-value for difference in estimate <0.001. Use of ICSI increased the odds of live birth, and male causes of infertility were associated with reduced odds of live birth only in couples who had not received ICSI. Prediction of live birth was feasible with moderate discrimination and excellent calibration; calibration was markedly improved in the novel compared to the established model. Preterm birth and low birth weight were increased if oocyte donation was required and ICSI was not used. Risk of macrosomia increased with advancing maternal age and a history of previous live births. Infertility due to cervical problems was associated with increased odds of all three outcomes—preterm birth, low birth weight, and macrosomia.
Conclusions
Pending external validation, our results show that couple- and treatment-specific factors can be used to provide infertile couples with an accurate assessment of whether they have low or high risk of a successful outcome following IVF
Mammalian adaptation of influenza A(H7N9) virus is limited by a narrow genetic bottleneck
Human infection with avian influenza A(H7N9) virus is associated mainly with the exposure to infected poultry. The factors that allow interspecies transmission but limit human-to-human transmission are unknown. Here we show that A/Anhui/1/2013(H7N9) influenza virus infection of chickens (natural hosts) is asymptomatic and that it generates a high genetic diversity. In contrast, diversity is tightly restricted in infected ferrets, limiting further adaptation to a fully transmissible form. Airborne transmission in ferrets is accompanied by the mutations in PB1, NP and NA genes that reduce viral polymerase and neuraminidase activity. Therefore, while A(H7N9) virus can infect mammals, further adaptation appears to incur a fitness cost. Our results reveal that a tight genetic bottleneck during avian-to-mammalian transmission is a limiting factor in A(H7N9) influenza virus adaptation to mammals. This previously unrecognized biological mechanism limiting species jumps provides a measure of adaptive potential and may serve as a risk assessment tool for pandemic preparedness.published_or_final_versio
Serum estradiol/progesterone ratio on day of embryo transfer may predict reproductive outcome following controlled ovarian hyperstimulation and in vitro fertilization
BACKGROUND: To determine whether estradiol-to-progesterone (E(2)/P) ratios at the time of embryo transfer (ET) have an effect on implantation and pregnancy in IVF cycles. METHODS: 239 women consecutively treated by IVF or ICSI were retrospectively analyzed and early luteal serum E(2 )and P were measured on the day of ET. Transfer occurred after a variable in vitro culture period ranging from 4–7 days after ovulation induction (OI). Following ET, serum E(2)/P ratios were calculated for clinical pregnancies, preclinical abortions and non-coneption cycles. RESULTS: Receiver-operator curve analysis demonstrated that the E(2)/P ratio could differentiate between clinical pregnancies and non-pregnant cycles (area under the curve on OI +4 days = 0.70; 95% CI = 0.60–0.80; p = 0.003, on OI +5 days = 0.76; 95% CI = 0.64–0.88; p = 0.001, OI +7 days = 0.85; 95% CI = 0.75–0.96; p < 0.0001). CONCLUSION: These retrospective data may hold prognostic value regarding endometrial receptivity as reflected by E(2)/P measurements and may help improve IVF treatment outcome. Further prospective studies should be undertaken to confirm these obersveration
Passive movement therapy in patients with moderate to severe paratonia; study protocol of a randomised clinical trial (ISRCTN43069940)
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Fluphenazine-induced acute and tardive dyskinesias in monkeys
Five Cebus apella monkeys were treated with biweekly injections of fluphenazine enanthate (0.1–3.2 mg/kg IM). Three of these completed 1 full year of treatment, one injured its leg after 6 months of treatment and was killed, and another died of unknown causes after 9 months of treatment. All monkeys displayed abnormal movements corresponding to the early appearing extrapyramidal symptoms of neuroleptic-treated patients. These consisted initially of slowing or absence of volitional movement, trembling of the hands, trembling of the entire body, and general drowsy behavior. As treatment progessed, a variety of abnormal postures and movements appeared after each injection that were not exacerbated by drug withdrawal and, as tested at the end of the year, could be abolished or prevented with benztropine mesylate (0.2–0.5 mg/kg IM). The three monkeys that completed 1 year of treatment with fluphenazine were then withdrawn from the drug. After withdrawal, all three developed movements similar in appearance to those of patients with tardive dyskinesia (TD). Reinstitution of fluphenazine treatment, as tested in one monkey, abolished all movements resembling TD.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46432/1/213_2004_Article_BF00555204.pd
Hormone replacement therapy and risk of epithelial ovarian cancer
It has been suggested that oestrogen replacement therapy is associated with risk of epithelial ovarian cancer of the endometrioid type. Using data from an Australian population-based case–control study, the relation between unopposed oestrogen replacement therapy and epithelial ovarian cancer, both overall and according to histological type, was examined. A total of 793 eligible incident cases of epithelial ovarian cancer diagnosed from 1990 to 1993 among women living in Queensland, New South Wales and Victoria were identified. These were compared with 855 eligible female controls selected at random from the electoral roll, stratified by age and geographic region. Trained interviewers administered standard questionnaires to obtain detailed reproductive and contraceptive histories, as well as details about hormone replacement therapy and pelvic operations. No clear associations were observed between use of hormone replacement therapy overall and risk of ovarian cancer. Unopposed oestrogen replacement therapy was, however, associated with a significant increase in risk of endometrioid or clear cell epithelial ovarian tumours (odds ratio (OR) 2.56; 95% confidence interval (CI) 1.32–4.94). In addition, the risk associated with oestrogen replacement therapy was much larger in women with an intact genital tract (OR 3.00; 95% Cl 1.54–5.85) than in those with a history of either hysterectomy or tubal ligation. Post-menopausal oestrogen replacement therapy may, therefore, be a risk factor associated with endometrioid and clear cell tumours in particular. Additionally, the risk may be increased predominantly in women with an intact genital tract. These associations could reflect a possible role of endometriosis in the development of endometrioid or clear cell ovarian tumours. © 1999 Cancer Research Campaig
Glycans as receptors for influenza pathogenesis
Influenza A viruses, members of the Orthomyxoviridae family, are responsible for annual seasonal influenza epidemics and occasional global pandemics. The binding of viral coat glycoprotein hemagglutinin (HA) to sialylated glycan receptors on host epithelial cells is the critical initial step in the infection and transmission of these viruses. Scientists believe that a switch in the binding specificity of HA from Neu5Acα2-3Gal linked (α2-3) to Neu5Acα2-6Gal linked (α2-6) glycans is essential for the crossover of the viruses from avian to human hosts. However, studies have shown that the classification of glycan binding preference of HA based on sialic acid linkage alone is insufficient to establish a correlation between receptor specificity of HA and the efficient transmission of influenza A viruses. A recent study reported extensive diversity in the structure and composition of α2-6 glycans (which goes beyond the sialic acid linkage) in human upper respiratory epithelia and identified different glycan structural topologies. Biochemical examination of the multivalent HA binding to these diverse sialylated glycan structures also demonstrated that high affinity binding of HA to α2-6 glycans with a characteristic umbrella-like structural topology is critical for efficient human adaptation and human-human transmission of influenza A viruses. This review summarizes studies which suggest a new paradigm for understanding the role of the structure of sialylated glycan receptors in influenza virus pathogenesis.National Institute of General Medical Sciences (U.S.) (Glue Grant U54 GM62116)National Institutes of Health (U.S.) (Grant GM57073)Singapore-MIT Alliance for Research and Technolog
Rapid and Highly Informative Diagnostic Assay for H5N1 Influenza Viruses
A highly discriminative and information-rich diagnostic assay for H5N1 avian influenza would meet immediate patient care needs and provide valuable information for public health interventions, e.g., tracking of new and more dangerous variants by geographic area as well as avian-to-human or human-to-human transmission. In the present study, we have designed a rapid assay based on multilocus nucleic acid sequencing that focuses on the biologically significant regions of the H5N1 hemagglutinin gene. This allows the prediction of viral strain, clade, receptor binding properties, low- or high-pathogenicity cleavage site and glycosylation status. H5 HA genes were selected from nine known high-pathogenicity avian influenza subtype H5N1 viruses, based on their diversity in biologically significant regions of hemagglutinin and/or their ability to cause infection in humans. We devised a consensus pre-programmed pyrosequencing strategy, which may be used as a faster, more accurate alternative to de novo sequencing. The available data suggest that the assay described here is a reliable, rapid, information-rich and cost-effective approach for definitive diagnosis of H5N1 avian influenza. Knowledge of the predicted functional sequences of the HA will enhance H5N1 avian influenza surveillance efforts
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