Y chromosome deletions in azoospermic and severely oligozoospermic men undergoing intracytoplasmic sperm injection after testicular sperm extraction

Y chromosome deletions encompassing the AZFc region have been reported in 13% of azoospermic men and 7% of severely oligozoospermic men. We examined the impact of these Y deletions on the severity of testicular defects in 51 azoospermic men undergoing intracytoplasmic sperm injection (ICSI) after testicular sperm extraction (TESE) and 30 men with severe oligozoospermia undergoing ICSI after ejaculation of spermatozoa. In addition, five azoospermic patients shown previously to have Y chromosome deletions underwent histological evaluation of their previously obtained testis biopsy specimens. A further 27 azoospermic men underwent TESE-ICSI, but not Y chromosome DNA testing. Ten of 51 azoospermic men (20%) who underwent TESE-ICSI and Y-DNA testing were found to be deleted for portions of the Y chromosome AZFc region. Of these 10, five had spermatozoa retrievable from the testis, and in two cases the wives became pregnant. Of the 41 azoospermic men with no Y chromosome deletion, 22 (54%) had spermatozoa retrievable from the testis, and in 12 cases (29%) the wives became pregnant. Four of 30 (13%) severely oligozoospermic patients were found to be deleted for AZFc and in three (75%) of these pregnancy was achieved. The other 26 severely oligozoospermic couples who had no AZFc deletions underwent ICSI, and 12 (46%) have an ongoing or delivered pregnancy. The embryo implantation rate was not significantly different for azoospermic (22%), oligozoospermic (16%), Y-deleted (14%) or Y-intact (18%) men. Of the total of 19 infertile men who had Y chromosome deletions, 14 had deletions within Y chromosome intervals 6D-6F, in the AZFc region. Twelve of those 14 had some spermatozoa (however few in number) in the ejaculate or testis. Five of the Y-deleted men had deletions that extended more proximally on the Y chromosome, and in none of these could any spermatozoa be observed in either ejaculate or testis. These results support the concept that, in azoospermic or oligozoospermic men with Y chromosome deletions limited to intervals 6D-6F (AZFc), there are generally very small numbers of testicular or ejaculated spermatozoa. Larger Y deletions, including and extending beyond the AZFc region and encompassing more Y genes, tend to be associated with a total absence of testicular spermatozoa. In those cases where spermatozoa were retrieved, the presence of Y deletions had no obvious impact on fertilization or pregnancy rate.     

Comparison of the expression of interferon gamma, IL2, IL4, and lymphotoxin mRNA in experimental autoimmune uveoretinitis

The aim of this study was to investigate the T lymphocyte subsets involved in experimental autoimmune uveoretinitis (EAU) by quantifying the numbers of cells expressing mRNA for each of the lymphokines interferon gamma, interleukin 2, interleukin 4, and lymphotoxin throughout the disease process. Lewis rats were immunised with retinal S-antigen to provide a model of inflammatory eye disease. In situ hybridisation using cDNA probes specific for interferon gamma, IL2, IL4, and lymphotoxin mRNA were utilised to localise lymphokine mRNA expression by infiltrating cells and the numbers of positive cells counted. Localisation of mRNA for all four probes was found on increasing cell numbers as the disease process progressed. Similar numbers of cells expressed mRNA for each lymphokine, generally a small percentage of the T lymphocyte total. Activated cells within the eye express mRNA for interferon gamma, IL2, IL4, and lymphotoxin in EAU suggesting a mixed population of T lymphocyte subsets.     

Magnetic resonance imaging of the pelvic floor in the postpartum patient

Magnetic resonance imaging (MRI) was used to assess anatomical changes in the pelvic floor after childbirth. Six women underwent serial MRI examination within 30 hours and at 1 week, 2 weeks, 6 weeks and 6 months after delivery; 8 additional women were studied only within 30 hours of delivery. T-1 and T-2-weighted images of the pelvis in the transverse and sagittal planes with a 1.5-T MR imager were obtained. In the sagittal section we assessed the urethrovesical angle, urethral length, distance from the symphysis to the proximal and distal vagina, vaginal length, width and length of the sphincters, and the presence of sphincter defects. Axial sections were assessed for sphincter defects for the distance between the symphysis and midurethra, vagina and rectum. Only one parameter (distance between symphysis and distal vagina) changed significantly over time, without a clear trend in direction. Interobserver variation was reasonable (<15%) except for anal canal length, urethral length and distance between symphysis and anus. There were no significant correlations between birthweight and MRI parameters. There was a non-significant association (P = 0.09) between the sole combined sphincter defect and rectal injury, but not with episiotomy or parity. We concluded that it is feasible to determine multiple measurements on MR images to evaluate structures of the pelvic floor.     

Male/female mentoring: turning potential risks into rewards

A mentor guides a protege in the direction which will best assist the protege in learning his or her job. When men and women act as mentors and proteges, they take several risks to achieve the rewards that come from mentoring. The author describes the rewards and focuses on the risks of such mentoring, which include the potential for sexual tension and involvement, misunderstandings stemming from different communication and management styles, coworkers' misperceptions of the mentoring relationship, resulting in negative office gossip, and the potential for sexual harassment. The author concludes by summarizing steps organizations can take to encourage beneficial mentoring between men and women     

Power rail logic: a low power logic style for digital GaAs circuits

This paper describes a new logic style called Power Rail Logic (PRL), which is compatible with direct-coupled FET logic (DCFL) circuits. Multiplexors, latches, flip-flops, and exclusive-OR gates can be built using this logic style. Compared to DCFL, PRL uses fewer transistors, has larger noise margins, and up to 40% lower power-delay products. A test chip containing 32-b barrel shifters designed in DCFL and in PRL was successfully fabricated and tested. Test results are given for both circuits     

Protein kinase A stimulates binding of multiple proteins to a U-rich domain in the 3'-untranslated region of lactate dehydrogenase A mRNA that is required for the regulation of mRNA stability

We have explored the molecular basis of the cAMP-induced stabilization of lactate dehydrogenase A (LDH-A) mRNA and identified four cytoplasmic proteins of 96, 67, 52, and 50 kDa that specifically bind to a 30-nucleotide uridine-rich sequence in the LDH 3'-untranslated region with a predicted stem-loop structure. Mutational analysis revealed that specific protein binding is dependent upon an intact primary nucleotide sequence in the loop as well as integrity of the adjoining double-stranded stem structure, thus indicating a high degree of primary and secondary structure specificity. The critical stem-loop region is located between nucleotides 1473 and 1502 relative to the mRNA cap site and contains a previously identified cAMP-stabilizing region (CSR) required for LDH-A mRNA stability regulation by the protein kinase A pathway. The 3'-untranslated region binding activity of the proteins is up-regulated after protein kinase A activation, whereas protein dephosphorylation is associated with a loss of binding activity. These results imply a cause and effect relationship between LDH-A mRNA stabilization and CSR-phosphoprotein binding activity. We propose that the U-rich CSR is a recognition signal for CSR-binding proteins and for an mRNA processing pathway that specifically stabilizes LDH mRNA in response to activation of the protein kinase A signal transduction pathway.     

Antegrade colonic enemas

Thirteen children aged 6-14 (mean 8) years in whom an antegrade colonic enema procedure was performed were reviewed retrospectively. All presented with refractory constipation or faecal soiling over a 3-year period. Nine of the children had previously undergone pull-through procedures for Hirschsprung's disease or high anorectal malformations. Two were suffering from spina bifida and two from idiopathic functional constipation. The operation was performed through a right iliac fossa incision. A catheterizable conduit was created. The appendix was brought out to the wound edge and made continent by intussuscepting the appendix base into the caecum. When the appendix was absent or unusable, a caecal tube was formed. Five patients suffered minor morbidity, six required a further operative procedure and two eventually required a sigmoid colostomy. However, the eventual outcome of a continent stoma was attained in 11 of the 13 children, all of whom would have been considered for sigmoid colostomy before introduction of the antegrade colonic enema procedure.     

New frequency-dependent edge mode current density approximationsfor TM scattering from a conducting strip grating

Two new frequency-dependent strip-grating current densities are derived for TM mode incidence on a conducting strip grating. The current densities are assumed to be the product of a spatial function and a frequency function. One spatial function is the traditional frequency-independent edge mode current density. The other is found by the use of conformal mapping. The frequency function is derived by use of the radiation integral and the periodic Green's function. The new resultant current densities are both exact for small strip widths. The conformally mapped solution is also valid for wide strips and is exact in the limit as the strip width equals the grating period. Although the solutions are not as accurate as the moment method at all frequencies, they produce computationally faster solutions and offer further insight into strip-grating behavior