Sonography in male infertility: a useful yet underutilized diagnostic tool.

PURPOSE: To assess the utility of comprehensive sonographic examination including scrotal sonography, Testicular Doppler and Transrectal Ultrasound (TRUS) to evaluate the male reproductive system and differentiate between obstructive (OG) and non-obstructive (NOG) causes of azoospermia. METHODS: 30 infertile men with azoospermia and 30 control subjects with normospermia underwent sonographic evaluation. FNAC/biopsy findings were used for assigning a final diagnosis of obstructive or non-obstructive azoospermia. Qualitative and quantitative imaging parameters were retrospectively compared between the groups using Chi-square/Fisher's exact test and unpaired t-test, respectively. P < 0.05 was considered significant. RESULTS: Ectasia of rete testis/epididymal tubules, altered epididymal echogenicity, dilated terminal vas deferens were significantly more common in OG while inhomogeneous testicular echo-texture and reduced testicular vascularity were more common in NOG (P < 0.05). Testicular volume and epididymal head size were significantly higher in OG than in NOG and controls (18.2 ml/10 mm Vs 8.2 ml/7.2 mm and 13.4 ml/8.8 mm respectively; P < 0.05); while Resistive Index (RI) of intra-testicular vessels was higher in NOG as compared to OG and controls (0.65 vs 0.54 and 0.52 respectively; P < 0.05). On ROC curve analysis, cut-off values of testicular volume (AUC: 0.939; P < 0.001), epididymal head size (AUC: 0.772; P = 0.001) and testicular RI (AUC: 0.761; P = 0.001) to differentiate between the groups were 12.1 ml (sensitivity-94.4%; specificity-83.3%), 9 mm (sensitivity-66.7%; specificity-71%) and 0.62 (sensitivity-62%; specificity-100%) respectively. CONCLUSION: Comprehensive sonographic evaluation can be used to differentiate obstructive from non-obstructive infertility and should be routinely incorporated in the diagnostic workup of infertile men with azoospermia.

MDM2 interacts with NME2 (non-metastatic cells 2, protein) and suppresses the ability of NME2 to negatively regulate cell motility.

MDM2 expression, combined with increased p53 expression, is associated with reduced survival in several cancers, but is particularly of interest in renal cell carcinoma (RCC) where evidence suggests the presence of tissue-specific p53/MDM2 pathway defects. We set out to identify MDM2-interacting proteins in renal cells that could act as mediators/targets of MDM2 oncogenic effects in renal cancers. We identified the non-metastatic cells 2, protein; NME2 (NDPK-B, NM23-B/-H2), a nucleoside diphosphate kinase, as an MDM2-interacting protein using both a proteomic-based strategy [affinity chromatography and tandem mass spectrometry [MS/MS] from HEK293 cells] and a yeast two-hybrid screen of a renal carcinoma cell-derived complementary DNA library. The MDM2-NME2 interaction is highly specific, as NME1 (87.5% amino acid identity) does not interact with MDM2 in yeast. Specific NME proteins display well-documented cell motility and metastasis-suppressing activity. We show that NME2 contributes to motility suppression under conditions where MDM2 is expressed at normal physiological/low levels. However, up-regulation of MDM2 in RCC cells abolishes the ability of NME2 to suppress motility. Significantly, when MDM2 expression is down-regulated in these cells using small interfering RNA, the motility-suppressing activity of NME2 is rescued, confirming that MDM2 expression causes the loss of NME2 cell motility regulatory function. Thus MDM2 up-regulation in renal cancer cells can act in a dominant manner to abrogate the function of a potent suppressor of motility and metastasis. Our studies identify a novel protein-protein interaction between MDM2 and NME2, which suggests a mechanism that could explain the link between MDM2 expression and poor patient survival in RCC.

Loss of MTBP expression is associated with reduced survival in a biomarker-defined subset of patients with squamous cell carcinoma of the head and neck.

BACKGROUND: Recent genetic studies have implicated p53 mutation as a significant risk factor for therapeutic failure in squamous cell carcinoma of the head and neck (SCCHN). However, in a recent meta-analysis in the literature of p53 from major anatomical subsites (larynx, oral cavity, oropharynx/hypopharynx), associations between patient survival and p53 status were ambiguous. METHODS: The authors examined a cohort of SCCHNs using a previously developed biomarker combination that likely predicts p53 status based on p53/MDM2 expression levels determined by immunohistochemistry (IHC). In addition, the authors generated and validated an antibody to MTBP (an MDM2 binding protein that alters p53/MDM2 homeostasis and may contribute to metastatic suppression) and have incorporated data for MTBP expression into the current analyses. RESULTS: Analysis of expression data for p53 and MDM2 in 198 SCCHN patient samples revealed that the biomarker combination p53 + ve/MDM2-low (likely indicative of p53 mutation) was significantly associated with reduced overall survival (log-rank P = .035) and was an independent prognostic factor (P = .013; HR, 1.705; 95% CI, 1.12-2.60); thus, these data were compatible with earlier genetic analyses. By using IHC for p53 and MDM2 to dichotomize patients, the authors found that loss of MTBP expression was significantly associated with reduced survival (log-rank P = .004) and was an independent prognostic factor (P = .004; HR, 2.78; 95% CI, 1.39-5.54) in p53 + ve/MDM2-low patients. CONCLUSIONS: These results represent the first examination of MTBP expression in human tissues and provide evidence for a p53 status-dependent role for MTBP in suppressing disease progression in SCCHN patients as well as confirming a role for p53 pathway function in delaying disease progression.

Endoplasmic reticulum-associated degradation of a degron-containing polytopic membrane protein.

The presence of two basic amino acids strategically located within a single spanning transmembrane region has previously been shown to act as a signal for the endoplasmic reticulum associated degradation (ERAD) of several polypeptides. In contrast, the functionality of this degron motif within the context of a polytopic membrane protein has not been established. Using opsin as a model system, we have investigated the consequences of inserting the degron motif in the first of its seven transmembrane (TM) spans. Whilst these basic residue reduce the binding of the targeting factor, signal recognition particle, to the first TM span, this has no effect on membrane integration in vitro or in vivo. This most likely reflects the presence of multiple TM spans that can act as targeting signals within in the nascent opsin chain. We find that the degron motif leads to the efficient retention of mutant opsin chains at the endoplasmic reticulum. The mutant opsin polypeptides are degraded via a proteasomal pathway that involves the actions of the E3 ubiquitin ligase HRD1. In contrast, wild-type opsin remains stable for a prolonged period even when artificially accumulated at the endoplasmic reticulum. We conclude that a single dibasic degron motif is sufficient to initiate both the ER retention and subsequent degradation of ospin via an ERAD pathway.

Mathematical models of the simplest fuzzy PI/PD controllers with skewed input and output fuzzy sets.

This paper unveils mathematical models for fuzzy PI/PD controllers which employ two skewed fuzzy sets for each of the two-input variables and three skewed fuzzy sets for the output variable. The basic constituents of these models are Gamma-type and L-type membership functions for each input, trapezoidal/triangular membership functions for output, intersection/algebraic product triangular norm, maximum/drastic sum triangular conorm, Mamdani minimum/Larsen product/drastic product inference method, and center of sums defuzzification method. The existing simplest fuzzy PI/PD controller structures derived via symmetrical fuzzy sets become special cases of the mathematical models revealed in this paper. Finally, a numerical example along with its simulation results are included to demonstrate the effectiveness of the simplest fuzzy PI controllers.

Sonography in male infertility: a look beyond the obvious.

Infertility affects 15-20% of the reproductive age range population; the male factor accounts for up to 40-60% of these. With female factor infertility catching most of the limelight in research, diagnosis and treatment, the other half of the problem has not been duly addressed. Imaging has an important role to play in the evaluation of male infertility, especially to identify correctible (obstructive) causes. We review the scrotal, trans-rectal sonographic and Doppler findings in infertile men to aid in the accurate diagnosis and proper management of such patients.

GSK-3 inhibitors induce chromosome instability.

BACKGROUND: Several mechanisms operate during mitosis to ensure accurate chromosome segregation. However, during tumour evolution these mechanisms go awry resulting in chromosome instability. While several lines of evidence suggest that mutations in adenomatous polyposis coli (APC) may promote chromosome instability, at least in colon cancer, the underlying mechanisms remain unclear. Here, we turn our attention to GSK-3 - a protein kinase, which in concert with APC, targets beta-catenin for proteolysis - and ask whether GSK-3 is required for accurate chromosome segregation. RESULTS: To probe the role of GSK-3 in mitosis, we inhibited GSK-3 kinase activity in cells using a panel of small molecule inhibitors, including SB-415286, AR-A014418, 1-Azakenpaullone and CHIR99021. Analysis of synchronised HeLa cells shows that GSK-3 inhibitors do not prevent G1/S progression or cell division. They do, however, significantly delay mitotic exit, largely because inhibitor-treated cells have difficulty aligning all their chromosomes. Although bipolar spindles form and the majority of chromosomes biorient, one or more chromosomes often remain mono-oriented near the spindle poles. Despite a prolonged mitotic delay, anaphase frequently initiates without the last chromosome aligning, resulting in chromosome non-disjunction. To rule out the possibility of "off-target" effects, we also used RNA interference to selectively repress GSK-3beta. Cells deficient for GSK-3beta exhibit a similar chromosome alignment defect, with chromosomes clustered near the spindle poles. GSK-3beta repression also results in cells accumulating micronuclei, a hallmark of chromosome missegregation. CONCLUSION: Thus, not only do our observations indicate a role for GSK-3 in accurate chromosome segregation, but they also raise the possibility that, if used as therapeutic agents, GSK-3 inhibitors may induce unwanted side effects by inducing chromosome instability.

MDM2 promotes cell motility and invasiveness through a RING-finger independent mechanism.

Recent studies connect MDM2 with increased cell motility, invasion and/or metastasis proposing an MDM2-mediated ubiquitylation-dependent mechanism. Interestingly, in renal cell carcinoma (RCC) p53/MDM2 co-expression is associated with reduced survival which is independently linked with metastasis. We therefore investigated whether expression of p53 and/or MDM2 promotes aggressive cell phenotypes. Our data demonstrate that MDM2 promotes increased motility and invasiveness in RCC cells (N.B. similar results are obtained in non-RCC cells). This study shows for the first time both that endogenous MDM2 significantly contributes to cell motility and that this does not depend upon the MDM2 RING-finger, i.e. is independent of ubiquitylation (and NEDDylation). Our data suggest that protein-protein interactions provide a likely mechanistic basis for MDM2-promoted motility which may constitute future therapeutic targets.