bluuebunny/crossref_metadata_2025 huggingface dataset:
17β-Estradiol downregulates interferon regulatory factor-1 in murine splenocytes
Authors: Lengi Andrea J , Phillips Rebecca A , Karpuzoglu Ebru , Ahmed Sattar Ansar
Published: December 2006

Interferon regulatory factor-1 (IRF-1) is an important transcription factor that mediates interferon-γ (IFN-γ)-induced cell-signaling events. In this study, we examined whether 17β-estradiol alters IRF-1 in splenic lymphocytes, in view of the immunomodulatory effects of this natural female sex hormone including its ability to alter IFN-γ levels. We find that IRF-1 expression is markedly downregulated in splenocytes or purified T-cells from estrogen-treated mice at all time points studied when compared with their placebo counterparts. This decrease in IRF-1 in splenocytes from estrogen-treated mice is neither due to upregulation of IRF-1-interfering proteins (nucleophosmin or signal transducer and activator of transcription (STAT)-5) nor due to alternatively spliced IRF-1 mRNA. Given that IFN-γ is a potent inducer of IRF-1, direct addition of recombinant IFN-γ to splenocytes from either wild-type or IFN-γ-knockout mice, or the addition of recombinant IFN-γ to purified T-cells, was expected to stimulate IRF-1 expression. However, robust expression of IRF-1 in cells from estrogen-treated mice was not seen, unlike what was observed in cells from placebo-treated mice. Diminished IFN-γ induction of IRF-1 in cells from estrogen-treated mice was noticed despite comparable phosphorylated STAT-1 activation. These studies are the first to show that estrogen regulates IFN-γ-inducible IRF-1 in lymphoid cells, a finding that may have implications to IFN-γ-regulated immune and vascular diseases.
DNA-remethylation around a STAT5-binding enhancer in the αS1-casein promoter is associated with abrupt shutdown of αS1-casein synthesis during acute mastitis
Authors: Vanselow Jens , Yang Wei , Herrmann Jens , Zerbe Holm , Schuberth Hans-Joachim , Petzl Wolfram , Tomek Wolfgang , Seyfert Hans-Martin
Published: December 2006

Prolactin stimulates the expression of milk genes during lactation through the activation of STAT5 transcription factors, which subsequently bind to their cognate target sequence on the promoters. Demethylation of 5methylCpG dinucleotides permits the tissue-specific accessibility of transcription factor-binding sites during development, but remethylation has not been shown to contribute to acute suppression of gene expression. We characterize functionally a novel STAT5-binding lactational enhancer in the far upstream promoter (~−10 kbp) of the bovine αS1-casein-encoding gene. This promoter area is hypo-methylated in the lactating udder only. Remethylation of this area accompanies an experimentally elicited acute shutdown of casein synthesis in fully lactating cows, whose udder quarters have experimentally been infected with a pathogenic E. coli strain. Within 24 h after infection, the relevant promoter area was remethylated from 10% of the DNA molecules in the uninfected control quarters to ~50% in the infected quarters, the typical values for fully lactating and not lactating udders respectively. Increased methylation resulted in tighter chromatin packing. Concomitantly, the αS1-casein mRNA concentration dropped to ~50% while the protein synthesis was shut down to ~2.5% in the infected quarters, alone. The methylation status of the promoter from a not lactationally regulated gene was unaltered, and the distal αS1-casein promoter was not remethylated in udder quarters with subclinical Staphylococcus aureus infections featuring sustained casein synthesis. Hence, infection-related remethylation of the αS1-casein promoter and chromatin remodelling serves as an acute, spatially restricted regulatory mechanism, which might insulate the promoter against the systemically unchanged high levels of circulating prolactin. This provides a rare example for an acute regulatory significance of CpG methylation.
Characterization of a new duplicate δ-opioid receptor from zebrafish
Authors: Pinal-Seoane Noelia , Martin Ivan Rodríguez , Gonzalez-Nuñez Veronica , de Velasco Ezequiel Marron Fernandez , Alvarez Francisco Alvar , Sarmiento Rogelio Gonzalez , Rodriguez Raquel E
Published: December 2006

A new full-length cDNA (ZFOR4) that encodes an opioid receptor has been isolated from the teleost zebrafish. The encoded polypeptide is 375 amino acids long and shows high sequence similarity to other δ-opioid receptors, including ZFOR1, the other δ-opioid receptor from zebrafish previously characterized by us. In situ hybridization studies have revealed that ZFOR4 mRNA is highly expressed in particular brain areas that coincide with the expression of the δ-opioid receptor in other species. Pharmacological analysis of ZFOR4 shows specific and saturable binding with [3H] diprenorphine, displaying one binding site with KD = 3.42 ± 0.38 nM and a receptor density of 6231 ± 335 fmol/mg protein. Competition-binding experiments were performed using [3H]diprenorphine and several unlabelled ligands (peptidic and non-peptidic). The order of affinity obtained is Met-enkephalin>Naloxone>Leu-enkephalin>Dynorphin A≫BW373U86>Morphine≫≫ [D-Pen2,D-Pen5]-Enkephalin, U69,593. [35S]GTPγS stimulation studies show that the endogenous ligands Met- and Leu-enkephalin and the non-peptidic δ agonist BW373U86 were able to fully activate ZFOR4. Our results prove the existence of two functional duplicate genes of the δ-opioid receptor in the teleost zebrafish.
Calnexin regulated gonadotropin-releasing hormone receptor plasma membrane expression
Authors: Brothers Shaun P , Janovick Jo Ann , Conn P Michael
Published: December 2006

A significant proportion of human gonadotropin-releasing hormone receptors (GnRHRs) are normally retained in the endoplasmic reticulum (ER); however, nearly all rat GnRHRs are routed to the plasma membrane. When mutations are introduced into either receptor, considerably more of the proteins are recognized by the quality control system (QCS) as misfolded and retained compared with wild-type (WT) receptor, resulting in decreased signaling in the presence of agonist. Calnexin, a component of the QCS, decreased plasma membrane expression of the GnRHRs, an effect that was mediated by a physical interaction between the receptor and the calnexin. Only the human receptor showed reduced signaling because it had fewer spare receptors compared with the rat GnRHR, allowing calnexin to affect signaling. Calnexin did not affect receptor signaling when K191 was deleted from the human WT GnRHR. Removal of this amino acid decreases receptor misfolding and increases plasma membrane expression. K191 is not present in the rat WT GnRHR. A pharmacological chaperone that corrects GnRHR misfolding, increased expression of the human WT GnRHR in the presence of calnexin. Calnexin apparently retains misfolded GnRHRs but routes correctly folded receptors to the plasma membrane. Mutation of a calnexin protein kinase C consensus phosphorylation site promoted increased retention of the human GnRHR, suggesting that calnexin phosphorylation controls the retention mechanism. We conclude that a proportion of the human and the rat WT GnRHR appears to be retained in the ER by calnexin, an effect that decreases GnRHR signaling capacity.
Expression and localization of the progesterone receptor in mouse and human reproductive organs
Authors: Teilmann Stefan Cuoni , Clement Christian Alexandro , Thorup Jørgen , Byskov Anne Grete , Christensen Søren Tvorup
Published: December 2006

The effects of gonadotropins on progesterone receptor (PR) expression and localization in the mouse oviduct, uterus, and ovary was examined. In the oviduct ciliated epithelial cells of adult mice and human revealed a unique PR localization to the lower half of the motile cilia whereas the nuclei were unstained or faintly stained. Pubertal female mice were further studied by confocal laser scanning microscopy and western blotting before and after injection with FSH and LH followed by human chorionic gonadotropin (hCG) injection after a 48-h period. PR immunolocalization to the oviduct cilia was greatly increased in pubertal mice upon hCG stimulation. In neighboring goblet cells, the PR staining was confined to the nuclei. Nuclear PR localization was evident in epithelial cells of the uterus as well as in a fraction of stromal and muscle cells. Staining intensity and number of stained cells was not affected by hormone stimulation. In the ovary, weak PR immunolocalization was observed in unprimed animals but increased significantly after hCG stimulation. In granulosa cells of preovulatory follicles PR was exclusively observed in mural cells, whereas cumulus cells remained negative. At all stages examined, primary granulosa cell cilia lacked PR staining. SDS-PAGE and western blotting analysis of tissues from oviduct, uterus, and ovary confirmed antibody specificity, and identified two bands corresponding to the PR isoforms PR-A and PR-B. Upon hCG stimulation, a new band cross-reacting with anti-PR emerged above the PR-A form in oviduct fractions, suggesting LH-induced phosphorylation of PR-A. We suggest that ciliary PR in the oviduct plays a role in progesterone signaling after ovulation, possibly via non-genomic events. These novel findings warrant further studies of oviduct and postovulatory signaling events and suggest a sensory role for oviduct cilia in the process of oocyte transport/fertilization.
Photoperiodic regulation of cellular retinoic acid-binding protein 1, GPR50 and nestin in tanycytes of the third ventricle ependymal layer of the Siberian hamster
Authors: Barrett Perry , Ivanova Elena , Graham E Scott , Ross Alexander W , Wilson Dana , Plé Helene , Mercer Julian G , Ebling Francis J , Schuhler Sandrine , Dupré Sandrine M , Loudon Andrew , Morgan Peter J
Published: December 2006

Tanycytes in the ependymal layer of the third ventricle act both as a barrier and a communication gateway between the cerebrospinal fluid, brain and portal blood supply to the pituitary gland. However, the range, importance and mechanisms involved in the function of tanycytes remain to be explored. In this study, we have utilized a photoperiodic animal to examine the expression of three unrelated gene sequences in relation to photoperiod-induced changes in seasonal physiology and behaviour. We demonstrate that cellular retinoic acid-binding protein 1 (CRBP1), a retinoic acid transport protein, GPR50, an orphan G-protein-coupled receptor and nestin, an intermediate filament protein, are down-regulated in short-day photoperiods. The distribution of the three sequences is very similar, with expression located in cells with tanycyte morphology in the region of the ependymal layer where tanycytes are located. Furthermore, CRBP1 expression in the ependymal layer is shown to be independent of a circadian clock and altered testosterone levels associated with testicular regression in short photo-period. Pinealectomy of Siberian hamsters demonstrates CRBP1 expression is likely to be dependent on melatonin output from the pineal gland. This provides evidence that tanycytes are seasonally responsive cells and are likely to be an important part of the mechanism to facilitate seasonal physiology and behaviour in the Siberian hamster.
Molecular cloning and characterization of the human WISP-2/CCN5 gene promoter reveal its upregulation by oestrogens
Authors: Fritah Asmaà , Redeuilh Gérard , Sabbah Michèle
Published: December 2006

Wnt-1-induced signalling pathway protein-2 (WISP-2)/connective tissue growth factor/cysteine-rich 61/nephroblastoma overexpressed (CCN)5 is a member of the CCN family of growth factors and was identified as an oestrogen- inducible gene in the MCF-7 cell line. However, the role of WISP-2/CCN5 in breast carcinogenesis remains unclear. In this study, we examined the mechanism by which oestrogens regulate the expression of human (h) Wnt-1 induced signalling pathway protein (WISP-2)/CCN5. Real-time RT-PCR showed that hWISP-2/CCN5 mRNA transcripts level is upregulated by oestrogens in the oestrogen receptor-positive human breast cancer cell lines MCF-7, T47D and ZR-75.1. Cloning of a 1.9 kb fragment of the hWISP-2/CCN5 5′-flanking sequence and subsequent analysis of potential transcription factor-binding sites identified a functional oestrogen response element site located between − 581 and − 569 upstream from the oestrogen-induced transcription start site. Transient transfections of MCF-7 cells with the cloned fragment showed that oestradiol caused an increase in reporter gene activity, which was inhibited by anti-oestrogens ICI 182 780 and 4-hydroxyta-moxifen. Chromatin immunoprecipitation analysis revealed an oestradiol-dependent recruitment of the oestrogen receptor α to the oestrogen- responsive region of the hWISP-2/CCN5 gene promoter. We also showed that endogenous CREB-binding protein (CBP) and p21WAF1/CIP1 are recruited to the chromosomal hWISP-2/CCN5 promoter in MCF-7 cells in an oestrogen-dependent manner, suggesting that CBP and p21WAF1/CIP1 participate in the oestrogen receptor α-mediated transcriptional control of the hWISP-2/CCN5 gene.
Estrogen receptor regulates insulin-like growth factor-I receptor gene expression in breast tumor cells: involvement of transcription factor Sp1
Authors: Maor Sharon , Mayer Doris , Yarden Ronit I , Lee Adrian V , Sarfstein Rive , Werner Haim , Papa Moshe Z
Published: December 2006

The insulin-like growth factors, IGF-I and IGF-II are a familyof mitogenic polypeptides with important roles in growth and differentiation. The biological actions of the IGFs are mediated by the IGF-I receptor (IGF-IR), a cell-surface tyrosine kinase, whose activation by serum IGF-I seems to be a key step in breast cancer initiation. Evidence accumulated indicates that estrogens stimulate the expression and activity of IGF axis components. The aim of our study was to examine the transcriptional mechanisms involved in regulation of IGF-IR gene expression by the estrogen receptor (ER). For this purpose, transient transfections using an IGF-IR promoter-luciferase reporter plasmid were performed in breast cancer-c derived ER-positive MCF-7 cells and isogenic ER-negative C4 cells. To examine the potential involvement of zinc-finger nuclear proteins in the transactivating effect of estrogens, chromatin immunoprecipitation (ChIP) experiments were performed using an Sp1 antibody, along with the Sp1-family-binding inhibitor Mithramycin A. The results obtained indicate that basal IGF-IR promoter activity was 5.8-fold higher in MCF-7 than in C4 cells. Estradiol treatment significantly activated the IGF-IR promoter in MCF-7, but not in C4 cells. Furthermore, the estrogen responsive region in the IGF-IR promoter was mapped to a GC-rich sequence located between nucleotides −40 and −188 in the 5′ flanking region. ChIP experiments revealed that at least part of the estrogen effect on IGF-IR expression was mediated through activation of the Sp1 transcription factor. In summary, our studies demonstrate that IGF-IR gene transcription in breast cancer cells is controlled by interactions between ERα and Sp1. Dysregulated expression of the IGF-IR gene may have pathologic consequences with relevance in breast cancer etiology.
Aromatase activity of human mesenchymal stem cells is stimulated by early differentiation, vitamin D and leptin
Authors: Pino Ana María , Rodríguez Juan Manuel , Ríos Susana , Astudillo Pablo , Leiva Laura , Seitz Germán , Fernández Mireya , Rodríguez J Pablo
Published: December 2006

Human mesenchymal stem cells (hMSCs) are multipotent cells present in bone marrow, which differentiate into osteoblasts and adipocytes, among other lineages. Oestrogens play a critical role in bone metabolism; its action may affect the adipocyte to osteoblast ratio in the bone marrow. In hMSCs, oestrogens are synthesized from C19 steroids by the enzyme aromatase cytochrome P450. In this study, we assessed whether aromatase enzymatic activity varied through early osteogenic (OS) and adipogenic (AD) differentiation. Also, we studied the effect of leptin and 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) on aromatase cell activity. Finally, we analysed whether conditions that modify oestrogen generation by cells affected hMSCs differentiation. For these purposes, hMSCs derived from post-menopausal women (65–86 years old) were cultured under basal, OS or AD conditions, in the presence or the absence of leptin and 1,25(OH)2D3. Aromatase activity was measured by the tritiated water release assay and by direct measurement of steroids synthesized from 3H-labelled androstenedione or testosterone. Our results showed that different OS and AD patterns of aromatase activity developed during the first period of differentiation (up to 7 days). A massive and sharp surge of aromatase activity at 24 h characterized early OS differentiation, while increased but constant aromatase activity was increased through adipogenesis. Both leptin and vitamin D increased aromatase activity during osteogenesis, but not during adipogenesis; finally, we showed that favourable aromatase substrates concentration restrained MSCs adipogenesis but improved osteogenesis. Thus, it could be inferred that a high and early increase of local oestrogen concentration in hMSCs affects their commitment either restraining AD or facilitating OS differentiation, or both.
Progesterone initiates Wnt-β-catenin signaling but estradiol is required for nuclear activation and synchronous proliferation of rat uterine stromal cells
Authors: Rider Virginia , Isuzugawa Kazuto , Twarog Meryl , Jones Stacy , Cameron Brent , Imakawa Kazuhiko , Fang Jianwen
Published: December 2006

Progesterone pretreatment of ovariectomized rat uteri increases the number of synchronously proliferating stromal cells in response to estradiol 17-β. To identify the signals involved in stimulating synchronous proliferation, sexually mature ovariectomized rats were injected with progesterone (2 mg) for 3 consecutive days. Estradiol 17-β (0.2 μg) was administered to initiate cell cycle entry. Uterine samples were removed at various times after hormone administration and changes in wingless (Wnt) pathway effectors and gene targets were identified by microarray. Progesterone pretreatment decreased glycogen synthase kinase-3β (GSK-3β) and increased expression of T-cell factor/lymphoid enhancer factor (TCF/LEF). GSK-3β protein decreased markedly in the uterine stroma of progesterone-pretreated uteri with the concomitant appearance of β-catenin in these stromal cells. Translocation of β-catenin from the cytosol to the nuclei in progesterone-pretreated stromal cells was stimulated in response to estradiol. β-Catenin binding to TCF/LEF increased (P<0.05) in progesterone-pretreated uteri in response to estradiol. Progesterone stimulated the expression of the Wnt target gene urokinase plasminogen activator receptor (uPA-R) in the periluminal uterine stromal cells. The expression of uPA-R increased in progesterone-pretreated stromal cells in response to estradiol administration. Together, the results indicate that progesterone initiates Wnt signaling in the uterine stroma by down-regulating GSK-3β. However, nuclear translocation of β-catenin and sufficient complex formation with TCF/LEF to activate stromal cell cycle entry requires estradiol. Stimulation of a uterine stromal cell line to proliferate and differentiate resulted in β-catenin accumulation, suggesting that endocrine-dependent Wnt signaling controls proliferation and differentiation (decidualization).
Amelioration of diet-induced diabetes mellitus by removal of visceral fat
Authors: Pitombo Cid , Araújo Eliana P , De Souza Cláudio T , Pareja José C , Geloneze Bruno , Velloso Lício A
Published: December 2006

The effect of visceral fat removal upon glucose homeostasis, insulin signal transduction, and serum adipokine levels in an animal model of diet-induced obesity and diabetes mellitus (DIO) was evaluated. Swiss mice were initially divided into two groups fed with regular rodent chow or with chow containing 24 g% saturated fat (DIO). DIO mice became obese and overtly diabetic after 8 weeks. DIO mice were then divided into three groups: control, sham, and visceral (epididymal and perinephric) fat removal. All groups were submitted to evaluation of basal glucose and insulin levels and i.p. insulin tolerance test. Insulin signal transduction in muscle was evaluated by immunoprecipitation and immunoblot, and serum adipokine levels were determined by ELISA. DIO mice became diabetic (228 versus 115 mg/dl), hyperinulinemic (7.59 versus 3.15 ng/ml) and insulin resistant (Kitt 2.88 versus 4.97%/min) as compared with control. Visceral fat removal partially reverted all parameters (147 mg/dl glucose; 3.82 ng/ml insulin; and 4.20%/min Kitt). In addition, visceral fat removal completely reversed the impairment of insulin signal transduction through insulin receptor, insulin receptor substrate (IRS)-1, IRS-2 and Akt in muscle. Finally, serum levels of the pro-inflammatory cytokines tumour necrosis factor-α, interleukin (IL)-1β and IL-6 were significantly increased, while adiponectin levels were significantly reduced in DIO mice. After visceral fat removal the levels of adipokines returned to near control levels. The present study shows that removal of visceral fat improves insulin signal transduction and glucose homeostasis in an animal model of diet-induced obesity and diabetes mellitus and these metabolic and molecular outcomes are accompanied by the restoration of adipokine levels.
Increased Aneuploidy Rate in Sperm With Fragmented DNA as Determined by the Sperm Chromatin Dispersion (SCD) Test and FISH Analysis
Authors: Muriel Lourdes , Goyanes Vicente , Segrelles Enrique , Gosálvez Jaime , Alvarez Juan G. , Fernández José Luis
Published: December 2006

ABSTRACT:Previous studies suggest that sperm DNA fragmentation may be associated with aneuploidy. However, currently available tests have not made it possible to simultaneously perform DNA fragmentation and chromosomal analyses on the same sperm cell. The recently introduced sperm chromatin dispersion (SCD) test allows users to determine this relationship. Semen samples from 16 males, including 4 fertile donors, 7 normozoospermic, 3 teratozoospermic, 1 asthenozoospermic, and 1 oligoasthenoteratozoospermic, were processed for DNA fragmentation analysis by the SCD test using the Halosperm kit. Three‐color fluorescence in situ hybridization (FISH) was performed on SCD‐processed slides to determine aneuploidy for chromosomes X, Y, and 18. Spermatozoa with DNA fragmentation showed a 4.4 ± 1.9‐fold increase in diploidy rate and a 5.9 ± 3.5‐fold increase in disomy rate compared to spermatozoa without DNA fragmentation. The overall aneuploidy rate was 4.6 ± 2.0‐fold higher in sperm with fragmented DNA (Wilcoxon rank test:P< .001 in the 3 comparisons). A higher frequency of DNA fragmentation was found in sperm cells containing sex chromosome aneuploidies originated in both first and second meiotic divisions. The observed increase in aneuploidy rate in sperm with fragmented DNA may suggest that the occurrence of aneuploidy during sperm maturation may lead to sperm DNA fragmentation as part of a genomic screening mechanism developed to genetically inactivate sperm with a defective genomic makeup.
Calcium‐Modulated Rod Outer Segment Membrane Guanylate Cyclase Type 1 Transduction Machinery in the Testes
Authors: Jankowska Anna , Burczynska Beata , Duda Teresa , Warchol Jerzy B. , Sharma Rameshwar K.
Published: December 2006

ABSTRACT: The importance of the second messengers, Ca2+ and cyclic GMP, for the process of fertilization is well established; the mechanisms for their intracellular regulations in the testes are, however, poorly understood. This study documents the biochemical, molecular, and functional identity of a Ca2+‐modulated membrane guanylate cyclase transduction machinery in bovine testes. The machinery is both inhibited and stimulated by free Ca2+ levels. The Ca2+‐sensor component of the inhibitory mode of the machinery is GCAP1 (guanylate cyclase activating protein type 1) and for the stimulatory mode is S100B. The transduction component is a Ca2+‐driven rod outer segment membrane guanylate cyclase type 1, ROS‐GC1. The cyclase is predominantly expressed in spermatogenic cells. GCAP1 expression is restricted to a small population of spermatogonia, whereas S100B is present in the majority of spermatocytes and spermatids. The expression of GCAP1 and S100B in spermatocytes and spermatids is mutually exclusive.
Correlation Between Semen Parameters and the Hamster Egg Penetration Test (HEPT) Among Fertile and Subfertile Men in Singapore
Authors: Ho Lee Mee , Lim Alvin Soon Tiong , Lim Tse Hui , Hum Siew Chen , Yu Su Ling , Kruger Theunis Frans
Published: December 2006

ABSTRACT: The objective of this retrospective study was to distinguish between fertile and subfertile men based on their semen parameters and hamster egg penetration test (HEPT) outcome. This study involved 110 subfertile men recruited from an infertility clinic and 48 fertile men attending an antenatal clinic in Singapore. The men were required to donate a semen specimen for semen analysis and HEPT assay. The results indicated that the subfertile group had significantly lower normal sperm morphology according to the Tygerberg strict criteria, and lower progressive motility (P < .05). Semen volume, density, HEPT decondensation rate, and sperm penetration index were not significantly different between the 2 groups. Receiver operating characteristic curve analysis indicated that sperm morphology had the highest predictive power of 65.7% with a threshold value of 7%, and progressive motility had a predictive power of 61.8% with a threshold value of 50%. Using the tenth percentile of the fertile population as the cutoff, lower adjusted thresholds of 3% for sperm morphology and 28% for progressive motility were obtained, giving higher positive predictive values of 81.8% and 84.4%, respectively. This study shows that these new cutoff values can be used to screen the general population to identify subfertile men. In contrast, the HEPT proved to be an insensitive and unreliable assay in identifying subfertile males. To our knowledge the comparison of HEPT and semen parameters between subfertile and fertile men has not been previously reported in an Asian population.
Effect of Posture and Clothing on Scrotal Temperature in Fertile Men
Authors: Mieusset Roger , Bengoudifa Bourras , Bujan Louis
Published: December 2006

ABSTRACT: Investigation of the effects of body position and clothing on the temperature of the scrotum has given discordant results. The aim of the present study was to evaluate these effects in 13 fertile male volunteers in successive positions each held for 15 minutes, either Supine, Standing, Seated with legs apart, and Seated with legs crossed (n = 8) or Standing, Seated with legs crossed, and Standing (n = 5), at first naked and then clothed. The Standing naked position was that in which scrotal temperature reached the lowest point. Clothing increased the scrotal temperature compared with the naked state, whatever the position. The Seated with legs crossed position had specific characteristics: in the naked state, it was thermogenic and increased scrotal temperature as much as clothing in the Supine or Standing positions; in the clothed state, the increase in temperature was less than expected, which could indicate that local mechanisms are involved. Moreover, the Seated with legs crossed position had a persisting effect on scrotal temperature in the next position. These results have both pathophysiological and epidemiological implications.
Long‐Term Results of Autologous Venous Grafts for Penile Morphological Reconstruction
Authors: Hsu Geng‐Long , Chen Heng‐Shuen , Hsieh Cheng‐Hsing , Chen Robert M. , Wen Hsien‐Sheng , Liu Li‐Jen , Chua Ceferino
Published: December 2006

ABSTRACT: In order to evaluate the long‐term results of autologous venous grafts, we present an overview of patients who underwent a procedure utilizing a venous patch from the deep dorsal vein with or without combination of the cavernosal vein in treating penile deformity. From March 1995 to March 2005, a total of 85 consecutive patients with Peyronie disease or congenital penile deviation underwent venous grafting. Tunical corporotomy was covered using transplanted venous wall sutured microscopically to collagen bundles of the inner circular and outer longitudinal layer of the tunica albuginea. The vein was sutured with the serosal side outward, after it had been detubularized, properly constructed, and spliced together. In this cohort, 48 patients with Peyronie disease and 37 with congenital penile deviation were respectively categorized as belonging to the Peyronie and congenital groups. All patients were evaluated preoperatively and postoperatively with the International Index of Erectile Function (IIEF‐5) scoring, angle measurement of erectile penis, satisfaction with the penile shape, and a cavernosogram which was further available for 15 patients. Histological confirmation in 5 cases was followed up for up to 10 years. The mean angle improvement was 44.8 ± 3.6° for the Peyronie group and 37.6 ± 3.8° for the congenital group. A satisfactory penile shape was achieved in 77 (90.6%) patients, although 8 men (9.4%) complained of mild deviation of the penis (<15°). Erectile function was good in 81 patients, although 6 of them had to use oral sildenafil/tadalafil postoperatively. Overall, they had a mean preoperative IIEF‐5 score of 19.7 ± 2.8, which increased to a mean postoperative score of 21.6 ± 2.2. The cavernosograms consistently disclosed a good penile shape. The histological confirmation showed that the donor vein retained its histological character despite the fact that perfect coalescence and lining up with the tunica albuginea were noted. The autologous vein appears to be an acceptable graft material, and the transplanted vein may have a modeling action rather than a scaffolding role in venous patch surgery on the penile tunica albuginea. Careful microsurgical manipulation is required to achieve a satisfactory, sustainable outcome.
Cryptorchidism and Semen Quality: A TEM and Molecular Study
Authors: Moretti Elena , Di Cairano Giovanni , Capitani Serena , Scapigliati Giacomo , Baccetti Baccio , Collodel Giulia
Published: December 2006

ABSTRACT: Cryptorchidism is a pathological condition defined as the failure of the testis to descend into the scrotum, the location of the cryptorchid testis can be in the inguinal canal or in the prescrotal and abdominal area, sometimes resulting in atrophic seminiferous tubules. The aim of this study was to analyze semen quality of men who underwent orchidopexy for unilateral or bilateral cryptorchidism during childhood. Semen quality was investigated by light microscopy to evaluate sperm concentration and motility. Sperm morphology was performed by transmission electron microscope (TEM), and the data were mathematically elaborated. The presence of Y microdeletions was investigated by polymerase chain reaction. The effect of cryptorchidism on meiosis was explored by fluorescence in situ hybridization (FISH). The incidence of azoospermia was higher in the group with bilateral compared with unilateral cryptorchidism, and semen parameters were better in the unilateral group. Sperm pathologies detected by TEM indicated a severe deterioration of sperm quality in both groups. Necrosis and apoptosis appeared to be the most frequent pathologies, and their values reached statistical significance compared with those from fertile controls. The presence of chromosome Y microdeletions in patients with cryptorchidism and severe spermatogenetic defects is controversial. No microdeletions were found in this study. FISH values indicated that the mean percentage of gonosome disomies and diploidies were generally out of normal range, indicating a severe disturbance of meiotic segregation. The effects induced by cryptorchidism resolved in childhood seem to include a spermatogenetic impairment, leading to recommendation of detailed ultrastructural and chromosomal sperm analyses before undertaking assisted reproductive techniques.
Pesticides and Polychlorinated Biphenyls as Potential Risk Factors for Erectile Dysfunction
Authors: Polsky Jane Y. , Aronson Kristan J. , Heaton Jeremy P. W. , Adams Michael A.
Published: December 2006

ABSTRACT: While it is biologically plausible that environmental chemicals such as pesticides and polychlorinated biphenyls (PCBs) with suspected hormone disrupting properties may have an impact on risk of erectile dysfunction (ED), few epidemiologic studies have assessed this potential association. In a clinic‐based case‐control study in Kingston, Ontario, consenting subjects completed a questionnaire and donated 15 mL of blood for analysis of organochlorines and lipids by gas chromatography. Exposures were compared for 101 cases with ED and 234 comparable control subjects. For most PCB congeners and organochlorine pesticides, geometric mean levels are similar for cases and controls. Multivariate logistic regression results do not show an increased or decreased risk of ED associated with levels of most detectable environmental substances after adjustment for age, total lipids, and confounders. Levels of 2 of the ubiquitous chlorinated pesticides, oxychlordane and trans‐nonachlor, which are highly correlated, appear to associate with a reduced risk of ED, but the role of chance cannot be ruled out. To our knowledge, this study is the first to investigate the possible relationship between plasma levels of organochlorines and ED risk, and results do not provide evidence of an association.
Functional Characterization of Male Germ Cell‐Specific CREM Isoforms
Authors: Jaspers Saskia , Gellersen Birgit , Kempf Rita , Samalecos Annemarie , Bergmann Martin , Steger Klaus
Published: December 2006

ABSTRACT: Due to alternative promoter usage, splicing, and translational initiation, expression of the cAMP‐responsive element modulator (CREM) gene results in the production of functionally different CREM proteins with either activating or repressing potential on target gene expression. Recently, we demonstrated 2 novel isoforms (CREM‐θ2‐F‐G‐H‐Ib and CREM‐θ2‐G‐H‐Ib) in various germ cell types during normal and impaired human spermatogenesis. In contrast to known isoforms, these exhibit a transactivation domain but lack a kinase‐inducible domain (KID) domain resulting in a disruption of the open reading frame. In the present study, we functionally analyzed these isoforms. Investigation of both in vitro and in vivo expressed proteins from human testis RNA suggests that a novel upstream open reading frame in exon θ2 is translated from isoform CREM‐θ2‐F‐G‐H‐Ib, giving rise to a full‐length protein. Furthermore, in both isoforms, usage of downstream adeninethymine‐guanines (ATGs) for translation initiation could be observed. Sequence‐specific DNA binding of CREM isoforms was confirmed by electrophoretic mobility shift assays. Luciferase reporter gene assays in cells transfected with novel CREM cDNAs demonstrated that protein kinase A dependent stimulation was inhibited by coexpression of CREM‐θ2‐F‐G‐H‐Ib but not of CREM‐θ2‐G‐H‐Ib.
Synthesis and selective antitubercular and antimicrobial inhibitory activity of 1-acetyl-3,5-diphenyl-4,5-dihydro-(1h)-pyrazole derivatives
Authors: Chovatia P.T. , Akabari J.D. , Kachhadia P.K. , Zalavadia P.D. , Joshi H.S.
Published: December 2006

The new compounds 1-aryl-3-{1-phenyl-3-[p (methylthio)phenyl]pyrazol-4-yl}-2-propen-1-ones 2a?l were prepared by the condensation of 1-phenyl-3-[p (methylthio)phenyl]-4-formylpyrazole 1 with different aryl ketones. Compounds 2a?l in reaction with hydrazine hydrate yielded 3-aryl-5-{1-phenyl-3-[p-(methylthio)phenyl]pyrazol-4 yl}-4,5-dihydro-(1H)-pyrazoles 3a?l and in the presence of hydrazine hydrate in glacial acetic acid gave 1-acetyl-3-aryl 5-{1-phenyl-3-[p-(methylthio)phenyl]pyrazol-4-yl}-4,5 dihydro-(1H)-pyrazoles 4a?l. These compounds were tested in vitro for their antitubercular and antimicrobial activities. The in vitro antimycobacterial activity of the newly synthesized compounds was investigated against Mycobacterium tuberculosis H37RV (ATCC 27294) in BACTEC 12B medium using the ALAMAR radiometric system. The antimicrobial in vitro activity was tested against Bacillus coccous, Bacillus subtilis Escherichia coli, Proteus vulgaris and antifungal activity against Aspergillus niger. The structures of the synthesized compounds were assigned on the basis of elemental analysis IR, 1H NMR and mass spectral data.
Kinetics of aniline polymerization initiated with iron(III) chloride
Authors: Nestorovic Gordana , Jeremic Katarina , Jovanovic Slobodan
Published: December 2006

The reaction kinetics of the chemical polymerization of aniline in aqueous acid solutions with FeCl3 as the oxidant (initiator) was investigated at 25?C. The polymerization was performed in a special reactor which enabled the initial concentration of oxidant to be kept constant during the polymerization reaction. The order of the reaction of ANI polymerization with respect to FeCl3 was calculated as n=0.18. The rate constant k of the polymerization reaction was found to be 9.1x10-5(mol dm-3)-1,18 s-1. The theoretical yield of the reaction was calculated using the Faraday law and the experimentally determined quantity of electricity exchanged during the polymerization reaction. There was a discrepancy between the experimentally and theoretically determined yield, indicating that the oxidant was being consumed in some side reactions, which is an accordance with the fact that the order of the reaction of ANI polymerization with respect to FeCl3 is a non-integer number.
Control of Metabolism and Growth Through Insulin-Like Peptides inDrosophila
Authors: Géminard Charles , Arquier Nathalie , Layalle Sophie , Bourouis Marc , Slaidina Maija , Delanoue Renald , Bjordal Marianne , Ohanna Mickael , Ma May , Colombani Julien , Léopold Pierre
Published: December 2006

Insulin signaling is a conserved feature in all metazoans. It evolved with the appearance of multicellularity, allowing primordial metazoans to respond to a greater diversity of environmental signals. The insulin signaling pathway is highly conserved in insects and particularly in Drosophila, where it has been extensively studied in recent years and shown to control metabolism, growth, reproduction, and longevity. Because misregulation of the insulin/IGF pathway in humans plays a role in many medical disorders, such as diabetes and various types of cancer, unraveling the regulation of insulin/IGF signaling using the power of a genetically tractable organism like Drosophila may contribute to the amelioration of these major human pathologies.
Glucokinase Regulatory Network in Pancreatic β-Cells and Liver
Authors: Baltrusch Simone , Tiedge Markus
Published: December 2006

The low-affinity glucose-phosphorylating enzyme glucokinase (GK) is the flux-limiting glucose sensor in liver and β-cells of the pancreas. Furthermore, GK is also expressed in various neuroendocrine cell types. This review describes the complex network of GK regulation, which shows fundamental differences in liver and pancreatic β-cells. Tissue-specific GK promoters determine a higher gene expression level and glucose phosphorylation capacity in liver than in pancreatic β-cells. The second hallmark of tissue-specific GK regulation is based on posttranslational mechanisms in which the high-affinity regulatory protein in the liver undergoes glucose- and fructose-dependent shuttling between cytoplasm and nucleus. In β-cells, GK resides outside the nucleus but has been reported to interact with insulin secretory granules. The unbound diffusible GK fraction likely determines the glucose sensor activity of insulin-producing cells. The bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2) has been identified as an activating binding partner of β-cell GK, increasing the Vmax value of the enzyme, while the S0.5 value for glucose remains unchanged. This effect is likely due to stabilization of a catalytically active enzyme conformation. The identification of chemical activators of GK paved the way to determining its crystal structure, revealing a catalytically less active super open conformation and a catalytically active closed conformation with a normal affinity for glucose. The glucose sensor function of GK in liver and β-cells results from the synergy of its regulatory properties with its transcriptionally and posttranslationally controlled levels. These factors have to be taken into account in designing pharmacotherapy for type 2 diabetes.
Pancreatic and Extrapancreatic Effects of Gastric Inhibitory Polypeptide
Authors: Yamada Yuichiro , Miyawaki Kazumasa , Tsukiyama Katsushi , Harada Norio , Yamada Chizumi , Seino Yutaka
Published: December 2006

The hormonal factor(s) implicated as transmitters of signals from the gut to pancreatic β-cells is referred to as incretin, and gastric inhibitory polypeptide (GIP) is identified as one of the incretins. GIP is a gastrointestinal peptide hormone of 42 amino acids that is released from duodenal endocrine K-cells after absorption of glucose or fat and exerts its effects by binding to its specific receptor, the GIP receptor. By generating and characterizing mice with a targeted mutation of the GIP receptor gene, we have shown that GIP has not only an insulinotropic role, but also physiological roles on fat accumulation into adipose tissues and calcium accumulation into bone. We here propose a new acronym, GIP, for gut-derived nutrient-intake polypeptide.
Impact of Gastric Bypass Surgery on Gut Hormones and Glucose Homeostasis in Type 2 Diabetes
Authors: Näslund Erik , Kral John G.
Published: December 2006

Gastric bypass surgery (GBP) for obesity, by constructing an isolated ∼30-ml proximal gastric pouch connected to a 75-cm limb of proximal jejunum, bypassing >90% of the stomach, the pylorus, and the duodenum, cures type 2 diabetes in >80% of cases. We review alterations in gastrointestinal peptide release after GBP that affect glucose disposal. We focus on ghrelin and the incretins glucose-dependent insulinotropic polypeptide, glucagon-like peptide 1, and peptide YY as the most likely candidates for increasing insulin sensitivity after these operations, even before substantial weight loss has occurred. Although we have limited our review to only four gastrointestinal peptides, others may be involved, as are adipocyte-derived molecules such as leptin and adiponectin, and substrate receptor interactions in target tissues including the brain.
Neuropeptides and the Regulation of Islet Function
Authors: Ahrén Bo , Wierup Nils , Sundler Frank
Published: December 2006

The pancreatic islets are richly innervated by autonomic nerves. The islet parasympathetic nerves emanate from intrapancreatic ganglia, which are controlled by preganglionic vagal nerves. The islet sympathetic nerves are postganglionic with the nerve cell bodies located in ganglia outside the pancreas. The sensory nerves originate from dorsal root ganglia near the spinal cord. Inside the islets, nerve terminals run close to the endocrine cells. In addition to the classic neurotransmitters acetylcholine and norepinephrine, several neuropeptides exist in the islet nerve terminals. These neuropeptides are vasoactive intestinal polypeptide, pituitary adenylate cyclase–activating polypeptide, gastrin-releasing polypeptide, and cocaine- and amphetamine-regulated transcript in parasympathetic nerves; neuropeptide Y and galanin in the sympathetic nerves; and calcitonin gene–related polypeptide in sensory nerves. Activation of the parasympathetic nerves and administration of their neurotransmitters stimulate insulin and glucagon secretion, whereas activation of the sympathetic nerves and administration of their neurotransmitters inhibit insulin but stimulate glucagon secretion. The autonomic nerves contribute to the cephalic phase of insulin secretion, to glucagon secretion during hypoglycemia, to pancreatic polypeptide secretion, and to the inhibition of insulin secretion, which is seen during stress. In rodent models of diabetes, the number of islet autonomic nerves is upregulated. This review focuses on neural regulation of islet function, with emphasis on the neuropeptides.
The Brain-Gut-Islet Connection
Authors: Woods Stephen C. , Benoit Stephen C. , Clegg Deborah J.
Published: December 2006

Peptide signals from the pancreatic islets and the gastrointestinal tract influence the regulation of energy homeostasis by the brain, and the brain in turn influences the secretions of both the islets and the gut. This article focuses on how insulin interacts with the brain to influence food intake, blood glucose, and cognitive behavior. Insulin is secreted in response to changes of ambient glucose, and the levels achieved are directly proportional to body adiposity. Hence, insulin, like leptin, is an adiposity signal. An increased insulin signal in the mediobasal hypothalamus indicates that ample or excess energy is available in the body and elicits responses that limit food intake and reduce hepatic glucose secretion. Increased insulin (and leptin as well) locally within the brain complements other signals that indicate a surfeit of energy in the body, including satiety signals generated by the gut during meals, glucose, and some fatty acids. There is compelling evidence that overlapping intracellular signaling pathways within the mediobasal hypothalamus mediate the overall catabolic response to these diverse metabolic signals. Insulin receptors are also densely expressed in the hippocampus, and insulin acts there to facilitate learning and memory. The function of insulin receptors in other brain areas is poorly understood. Obesity and/or the consumption of diets high in fat render the brain as well as the body insulin resistant. In the hypothalamus, this is manifest as a reduced ability of insulin to reduce food intake and body weight, and in the hippocampus, it is manifest as a reduced ability of insulin to improve learning and/or memory.
Central Regulation of Energy Homeostasis
Authors: Porte Daniel
Published: December 2006

Insulin has two important functions that relate to overall metabolic homeostasis. The phylogenetically oldest is the maintenance of sufficient energy stores to allow for development, growth, and reproduction. The newer is as a feedback regulator of plasma glucose. The key role of the central nervous system in both functions is reviewed from a personal perspective, and the development of the concept that both body weight (adiposity) and plasma glucose are critically regulated by the same hormone is described. The recent suggestion that diabetes and obesity are linked by their common reliance on this central nervous system insulin signaling system is reviewed. Recent efforts to understand the hypothalamic mechanisms involved are described, and the common use of insulin receptor substrate 2 and the phosphatidylinositol 3-kinase signaling mechanism is emphasized. Potential consequences of defects in the secretion of insulin or the action of insulin in the central nervous system are given, and linkage between obesity and diabetes is illustrated with a potential clinical representative.
Mechanisms of pathogenesis in Chagas disease
Authors: Kierszenbaum Felipe
Published: December 2006

Chagas disease, caused by the obligate unicellular parasite Trypanosoma cruzi, presents itself in a diverse collection of clinical manifestations, ranging from severe, fatal heart and digestive tract pathologies to unapparent or minor alterations that do not compromise survival. Over the years, a number of mechanisms have been proposed to explain the pathogenesis of chagasic tissue lesions, all of which have faced some criticism or been received with skepticism. This article excludes the autoimmunity hypothesis for Chagas disease because it has been extensively reviewed elsewhere, and summarizes the various alternative hypotheses that have been advanced over the years. For each of these hypotheses, an outline of its main tenets and key findings that support them is presented. This is followed by the results and comments that have challenged them and the caveats that stand on their way to wider acceptance. It is hoped that this writing will draw attention to our shortcomings in understanding the pathogenesis of Chagas disease, which, unfortunately, continues to figure among the most serious health problems of the American continent.