Human Y chromosome azoospermia factors (AZF) mapped to different subregions in Yq11

In a large collaborative screening project, 370 men with idiopathic azoospermia or severe oligozoospermia were analysed for deletions of 76 DNA loci in Yq11. In 12 individuals, we observed de novo microdeletions involving several DNA loci, while an additional patient had an inherited deletion. They were mapped to three different subregions in Yq11. One subregion coincides to the AZF region defined recently in distal Yq11. The second and third subregion were mapped proximal to it, in proximal and middle Yq11, respectively. The different deletions observed were not overlapping but the extension of the deleted Y DNA in each subregion was similar in each patient analysed. In testis tissue sections, disruption of spermatogenesis was shown to be at the same phase when the microdeletion occurred in the same Yq11 subregion but at a different phase when the microdeletion occurred in a different Yq11 subregion. Therefore, we propose the presence of not one but three spermatogenesis loci in Yq11 and that each locus is active during a different phase of male germ cell development. As the most severe phenotype after deletion of each locus is azoospermia, we designated them as: AZFa, AZFb and AZFc. Their probable phase of function in human spermatogenesis and candidate genes involved will be discussed.      

Thiol chemistry in peroxidase catalysis and redox signaling

The oxidation chemistry of thiols and disulfides of biologic relevance is described. The review focuses on the interaction and kinetics of hydrogen peroxide with low-molecular-weight thiols and protein thiols and, in particular, on sulfenic acid groups, which are recognized as key intermediates in several thiol oxidation processes. In particular, sulfenic and selenenic acids are formed during the catalytic cycle of peroxiredoxins and glutathione peroxidases, respectively. In turn, these enzymes are in close redox communication with the thioredoxin and glutathione systems, which are the major controllers of the thiol redox state. Oxidants formed in the cell originate from several different sources, but the major producers are NADPH oxidases and mitochondria. However, a different role of the oxygen species produced by these sources is apparent as oxidants derived from NADPH oxidase are involved mainly in signaling processes, whereas those produced by mitochondria induce cell death in pathways including also the thioredoxin system, presently considered an important target for cancer chemotherapy.     

Derivation of neural stem cells from mesenchymal stemcells: evidence for a bipotential stem cell population

Neural stem cell (NSC) transplantation has been proposed as a future therapy for neurodegenerative disorders. However, NSC transplantation will be hampered by the limited number of brain donors and the toxicity of immunosuppressive regimens that might be needed with allogeneic transplantation. These limitations may be avoided if NSCs can be generated from clinically accessible sources, such as bone marrow (BM) and peripheral blood samples, that are suitable for autologous transplantation. We report here that NSCs can be generated from human BM-derived mesenchymal stem cells (MSCs). When cultured in NSC culture conditions, 8% of MSCs were able to generate neurospheres. These MSC-derived neurospheres expressed characteristic NSC antigens, such as nestin and musashi-1, and were capable of self-renewal and multilineage differentiation into neurons, astrocytes, and oligodendrocytes. Furthermore, when these MSC-derived neurospheres were cocultured with primary astrocytes, they differentiate into neurons that possess both dendritic and axonal processes, form synapses, and are able to fire tetrodotoxin-sensitive action potentials. When these MSC-derived NSCs were switched back to MSC culture conditions, a small fraction of NSCs (averaging 4-5%) adhered to the culture flasks, proliferated, and displayed the morphology of MSCs. Those adherent cells expressed the characteristic MSC antigens and regained the ability to differentiate into multiple mesodermal lineages. Data presented in this study suggest that MSCs contain a small fraction (averaging 4-5%) of a bipotential stem cell population that is able to generate either MSCs or NSCs depending on the culture conditions.     

Polar body based aneuploidy screening is poorly predictive of embryo ploidy and reproductive potential

Purpose

Polar body (polar body) biopsy represents one possible solution to performing comprehensive chromosome screening (CCS). This study adds to what is known about the predictive value of polar body based testing for the genetic status of the resulting embryo, but more importantly, provides the first evaluation of the predictive value for actual clinical outcomes after embryo transfer.

Methods

SNP array was performed on first polar body, second polar body, and either a blastomere or trophectoderm biopsy, or the entire arrested embryo. Concordance of the polar body-based prediction with the observed diagnoses in the embryos was assessed. In addition, the predictive value of the polar body -based diagnosis for the specific clinical outcome of transferred embryos was evaluated through the use of DNA fingerprinting to track individual embryos.

Results

There were 459 embryos analyzed from 96 patients with a mean maternal age of 35.3. The polar body-based predictive value for the embryo based diagnosis was 70.3 %. The blastocyst implantation predictive value of a euploid trophectoderm was higher than from euploid polar bodies (51 % versus 40 %). The cleavage stage embryo implantation predictive value of a euploid blastomere was also higher than from euploid polar bodies (31 % versus 22 %).

Conclusion

Polar body based aneuploidy screening results were less predictive of actual clinical outcomes than direct embryo assessment and may not be adequate to improve sustained implantation rates. In nearly one-third of cases the polar body based analysis failed to predict the ploidy of the embryo. This imprecision may hinder efforts for polar body based CCS to improve IVF clinical outcomes.     

The impact of the Calman-Hine report on the processes and outcomes of care for Yorkshire's breast cancer patients.

BACKGROUND: The 1995 Calman-Hine plan outlined radical reform of the UK's cancer services with the aim of improving outcomes and reducing inequalities in National Health Service cancer care. Its main recommendation was to concentrate care into the hands of site-specialist multidisciplinary teams. This study aimed to determine whether these teams improved processes and outcomes of care for breast cancer patients. PATIENTS AND METHODS: All patients diagnosed and treated with breast cancer in the Yorkshire region of the UK from 1995 to 2000 were identified within the Northern and Yorkshire Cancer Registry and Information Service database. Changes in the use of breast-conserving surgery, adjuvant radiotherapy following breast-conserving surgery and 5-year survival were assessed among these patients in relation to their managing breast cancer team's degree of adherence to the manual of cancer service standards (which outlines the specification of the 'ideal' breast cancer team) and the extent of site specialisation of each team's surgeons. RESULTS: Variation was observed in the extent to which the breast cancer teams in Yorkshire had conformed to the Calman-Hine recommendations. Increases in adherence to the recommendations in the manual of cancer service standards were associated with a reduction in the use of breast-conserving surgery [odds ratio (OR) = 0.83, 95% confidence interval (CI) = 0.70-0.98, P < 0.01]. Increases in both surgical specialisation (OR = 1.23, 95% CI = 1.00-1.55, P = 0.06) and adherence to the manual of cancer service standards (OR = 1.22, 95% CI = 0.97-1.52, P = 0.05) were associated with the increased use of radiotherapy following breast-conserving surgery. There was a trend towards improved 5-year survival (hazard ratio = 0.93, 95% CI = 0.86-1.01, P = 0.10) in relation to increasing surgical site specialisation. All these effects were present after adjustment for the casemix factors of age, stage of disease, socio-economic background and year of diagnosis. CONCLUSIONS: The extent of implementation of the Calman-Hine report has been variable and, on the basis of limited clinical and organisational information available, its recommendations appear to be associated with improvements in processes and outcomes of care for breast cancer patients.     

An obstetric analysis of fifty consecutive pregnancies after transfer of cryopreserved human embryos

This report describes the obstetric outcome in 50 pregnancies resulting from the transfer of human embryos that had been cryopreserved for up to 2 years. The duration of cryopreservation did not influence the pregnancy rate after thawed embryo transfer. Thirty-one babies have been born from 28 pregnancies and a further seven pregnancies are currently in the second and third trimesters. Twenty-eight percent of the pregnancies failed to progress beyond the first trimester. One pregnancy was terminated at 22 weeks' gestation because of severe fetal malformation. Important antenatal events included premature uterine activity in six patients although only one patient with a singleton pregnancy ultimately was delivered prematurely. Retroplacental hemorrhage occurred in four patients but was of clinical consequence in only one. There was a high incidence of breech presentation at term in singleton pregnancies (12%). The cesarean section rate in this series was 21%. An international registry of cryopreserved pregnancies would facilitate data collection in this relatively new clinical field.     

Effects of isradipine, a new calcium antagonist, on postpartum uterine activity

The effects of a new calcium antagonist, isradipine (PN 200-110) on postpartum uterine activity and the maternal cardiovascular system were investigated. Uterine activity was recorded by a microtip transducer catheter inserted transcervically within 45 min of normal vaginal delivery. 0.5 mg of isradipine was given as a bolus injection during 5 min to 7 women with spontaneous uterine activity and 1 mg was given during a 15-min period to another 8 women with oxytocin-stimulated uterine activity. Matched controls with similar pre-injection activity (+/- 5%) but not given the drug were selected for comparison. The effects of the drug in 3 women (given 1 mg of isradipine) were compared with those in matched controls and in women given 0.25 mg of terbutalin i.v. as a bolus injection. Isradipine had a marked inhibitory effect on both spontaneous and oxytocin-stimulated uterine activity. The inhibitory effect of 1 mg of isradipine seemed comparable to that of 0.25 mg of terbutalin. The inhibition occurred within 1-2 min after the injection and was sustained throughout the study period (2 h). A transient reduction of the systolic (mean maximum decrease 10-15%) and diastolic blood pressure (mean maximum decrease 15-20%) was seen, particularly during the injection period. Hypotension (systolic blood pressure less than 80 mmHg) was not recorded. A moderate increase in pulse rate (mean maximum increase 22-27%) was seen in all cases. The results show that isradipine given as a bolus injection can inhibit early postpartum uterine activity, with minimal side effects.     

High pregnancy rate after early human embryo freezing

Human embryos produced by in vitro fertilization (IVF) were frozen with 1,2-propanediol as a cryoprotectant. Embryo survival after thawing was related to the presence of a nucleus in frozen cells and decreased with the increasing number of cells in the frozen embryo. None of five embryos frozen 3 or 4 days after IVF survived when thawed. Of 48 early embryos (35 patients) frozen 1 or 2 days after IVF, 42 (87.5%) were transferred in 32 patients. Ten pregnancies were initiated after frozen embryo transfer (ET). If we exclude the three infertile patients who had sexual intercourse in the fertile period, the pregnancy rate for each patient who had 1- or 2-day frozen embryo(s) was 22% (7 of 32). One of the pregnancies was obtained after ET of a 1-cell pronucleated frozen and thawed embryo. The rate of ongoing pregnancies after triple fresh ET was 23%. In patients having four embryos obtained in a single IVF cycle, the expected overall liveborn rate in an IVF-ET program including embryo cryopreservation could theoretically equal that of natural human fertility.