bluuebunny/crossref_metadata_2025 huggingface dataset:
Fates of Neurotrophins after Retrograde Axonal Transport: Phosphorylation of p75NTR Is a Sorting Signal for Delayed Degradation
Authors: Butowt Rafal , von Bartheld Christopher S.
Published: August 2009

Neurotrophins can mediate survival or death of neurons. Opposing functions of neurotrophins are based on binding of these ligands to two distinct types of receptors: trk receptors and p75NTR. Previous work showed that target-derived NGF induces cell death, whereas BDNF and NT-3 enhance survival of neurons in the isthmo-optic nucleus of avian embryos. To determine the fate of retrogradely transported neurotrophins and test whether their sorting differs between neurotrophins mediating survival- or death-signaling pathways, we traced receptor-binding, sorting, and degradation kinetics of target-applied radiolabeled neurotrophins that bind in this system to trk receptors (BDNF, NT-3) or only to p75NTR (NGF). At the ultrastructural level, the p75NTR-bound NGF accumulates with a significant delay in multivesicular bodies and organelles of the degradation pathway on arrival in the cell body when compared with trk-bound BDNF or NT-3. This delayed lysosomal accumulation was restricted to target-derived NGF, but was not seen when NGF was supplied to the somain vitro. The kinase inhibitors K252a and Gö6976 alter the kinetics of organelle accumulation: phosphorylation of p75NTR is a sorting signal for delayed sequestering of p75NTR-bound NGF in multivesicular bodies and delayed degradation in lysosomes when compared with trk-bound neurotrophins. Mutagenesis and mass spectrometry studies indicate that p75NTR is phosphorylated by conventional protein kinase C on serine 266. We conclude that, in addition to the known phosphorylation of trks, the phosphorylation of p75NTR can also significantly affect neuronal survivalin vivoby changing the intracellular sorting and degradation kinetics of its ligands and thus signaling duration.
Regionalized Loss of Parvalbumin Interneurons in the Cerebral Cortex of Mice with Deficits in GFRα1 Signaling
Authors: Canty Alison J. , Dietze Jule , Harvey Michael , Enomoto Hideki , Milbrandt Jeffrey , Ibáñez Carlos F.
Published: August 2009

Inhibitory interneurons are crucially important for cerebral cortex function and behavior. The mechanisms controlling inhibitory interneuron diversification and allocation to distinct cortical areas remain poorly understood. GDNF (glial cell line-derived neurotrophic factor) and its receptor GFRα1 have been implicated in the development of GABAergic precursors but, because of the early lethality of null mutants, their roles in postnatal maturation and function of cortical interneurons are unknown. “cis-only” mutant mice lack GFRα1 only in cells that do not express the RET signaling receptor subunit and survive to adulthood. At birth, both null mutants andcis-only mice showed a specific loss of GABAergic interneurons in rostro- and caudolateral cortical regions but not in more medial areas. Unexpectedly, the adult cortex ofcis-only mice displayed a complete loss of parvalbumin (PV)-expressing GABAergic interneurons in discrete regions (PV holes) interspersed among areas of normal PV cell density. PV holes predominantly occurred in the visual and frontal cortices, and their size could be affected by neuronal activity. Consistent with deficits in cortical inhibitory activity, these mice showed enhanced cortical excitability, increased sensitivity to epileptic seizure, and increased social behavior. We propose that GFRα1 signaling guides the development of a subset of PV-expressing GABAergic interneurons populating discrete regions of the cerebral cortex and may thus contribute to the diversification and allocation of specific cortical interneuron subtypes.
17β-Estradiol Regulation of T-Type Calcium Channels in Gonadotropin-Releasing Hormone Neurons
Authors: Zhang Chunguang , Bosch Martha A. , Rick Elizabeth A. , Kelly Martin J. , Rønnekleiv Oline K.
Published: August 2009

T-type calcium channels are responsible for generating low-threshold spikes that facilitate burst firing and neurotransmitter release in neurons. Gonadotropin-releasing hormone (GnRH) neurons exhibit burst firing, but the underlying conductances are not known. Previously, we found that 17β-estradiol (E2) increases T-type channel expression and excitability of hypothalamic arcuate nucleus neurons. Therefore, we used ovariectomized oil- or E2-treated EGFP (enhanced green fluorescent protein)–GnRH mice to explore the expression and E2 regulation of T-type channels in GnRH neurons. Based on single-cell reverse transcriptase-PCR and real-time PCR quantification of the T-type channel α1subunits, we found that all three subunits were expressed in GnRH neurons, with expression levels as follows: Cav3.3 ≥ Cav3.2 > Cav3.1. The mRNA expression of the three subunits was increased with surge-inducing levels of E2 during the morning. During the afternoon, Cav3.3 mRNA expression remained elevated, whereas Cav3.1 and Cav3.2 were decreased. The membrane estrogen receptor agonist STX increased the expression of Cav3.3 but not Cav3.2 in GnRH neurons. Whole-cell patch recordings in GnRH neurons revealed that E2 treatment significantly augmented T-type current density at both time points and increased the rebound excitation during the afternoon. Although E2 regulated the mRNA expression of all three subunits in GnRH neurons, the increased expression combined with the slower inactivation kinetics of the T-type current indicates that Cav3.3 may be the most important for bursting activity associated with the GnRH/LH (luteinizing hormone) surge. The E2-induced increase in mRNA expression, which depends in part on membrane-initiated signaling, leads to increased channel function and neuronal excitability and could be a mechanism by which E2 facilitates burst firing and cyclic GnRH neurosecretion.
A Distinct Representation of Three-Dimensional Shape in Macaque Anterior Intraparietal Area: Fast, Metric, and Coarse
Authors: Srivastava Siddharth , Orban Guy A. , De Mazière Patrick A. , Janssen Peter
Published: August 2009

Differences in the horizontal positions of retinal images—binocular disparity—provide important cues for three-dimensional object recognition and manipulation. We investigated the neural coding of three-dimensional shape defined by disparity in anterior intraparietal (AIP) area. Robust selectivity for disparity-defined slanted and curved surfaces was observed in a high proportion of AIP neurons, emerging at relatively short latencies. The large majority of AIP neurons preserved their three-dimensional shape preference over different positions in depth, a hallmark of higher-order disparity selectivity. Yet both stimulus type (concave–convex) and position in depth could be reliably decoded from the AIP responses. The neural coding of three-dimensional shape was based on first-order (slanted surfaces) and second-order (curved surfaces) disparity selectivity. Many AIP neurons tolerated the presence of disparity discontinuities in the stimulus, but the population of AIP neurons provided reliable information on the degree of curvedness of the stimulus. Finally, AIP neurons preserved their three-dimensional shape preference over different positions in the frontoparallel plane. Thus, AIP neurons extract or have access to three-dimensional object information defined by binocular disparity, consistent with previous functional magnetic resonance imaging data. Unlike the known representation of three-dimensional shape in inferior temporal cortex, the neural representation in AIP appears to emphasize object parameters required for the planning of grasping movements.
Indonesia-China Relations: The Politics of Re-engagement
Authors: Sukma Rizal
Published: August 2009

Indonesia's relations with China began to improve in 1998. This paper argues that recent improvements in bilateral relations have been primarily the function of changes in Indonesia's domestic politics and China's policy toward Southeast Asia, which contributed to the creation of an atmosphere of trust and comfort in Jakarta's re-engagement with China.
Strategic Voting in India: Its Extent and Determinants in the 2004 General Election
Authors: Choi Jungug
Published: August 2009

This study explores the issue of "strategic voting" in India by using individual-level, nationwide survey data from the 2004 general election. It finds that Indian voters are more "strategic" than "expressive" if their preferred party is unlikely to win a given parliamentary seat. Furthermore, the variables of being Muslim and education are found not to be statistically significant determinants of strategic voting.
Administrative Reform in East Asia: The Importance of Multiple Principals
Authors: Ehrhardt George
Published: August 2009

This paper looks at how recent Japanese prime ministers have counterintuitively limited political control over the bureaucracy. It uses conflicts at the foreign and defense ministries to illustrate how the presence of multiple principals alters principal-agent theory and its implications for the politician-bureaucrat relationship. This study integrates the Japanese case into comparative scholarship on Taiwan and Korea.
Exploring a 21st-Century Japan-Philippine Security Relationship: Linking Two Spokes Together?
Authors: Cruz De Castro Renato
Published: August 2009

The article examines Tokyo's efforts to link the Philippine and the Japanese security spokes in the face of Beijing's moves to widen the cleavage between both countries' alliances with the U.S. and render them irrelevant. The article concludes that Manila and Tokyo must first reconfigure a defense relationship that is not merely a military aggregation but a political apparatus enabling them to constructively engage an emergent China.
The emotional state of society: History and the timeliness of the problem
Authors: Hunyady György
Published: August 2009

A kiterjedt nemzetközi vizsgálatok, amelyek a társadalmi közérzetet igyekeznek feltárni, kizárólag az egyének szubjektív jólétét tanulmányozzák és mérik. Az előadás azonban abból indul ki, hogy az egyén nemcsak önmagára koncentrálva él meg különböző helyzeteket, hanem mint a társadalom aktív alkotóeleme direkt módon is megtapasztalja és megítéli annak viszonyait, érzelmileg reagál rájuk, és ebben is ki van téve társai meggyőző vagy taszító hatásának. A társadalmi közérzet célzott kutatásának utolsó fázisára 2007–2008 fordulóján került sor, 600 fős rétegzett mintán. A strukturált interjúk 6 témakört érintettek: A) a vizsgálati személyek szubjektív jóllétét, hangulatát, elégedettségét, B) hogyan látják mások érzelmi állapotát, hogyan észlelik a társadalom más tagjainak viszonyulásait, C) a társadalom viszonyaival, intézményeivel szemben magának a kérdezettnek a kinyilvánított személyes attitűdjét, D) a tárgyi jellemzést, amelyet a vizsgálati személyek a társadalmi közállapotokról és intézményekről adtak, E) az emberi értékek és a társadalmi pozíciók látni vélt (disz)harmóniáját, F) összehasonlítást a múlt és jelen, a norma és a valóság között. A kérdezett válaszai és azok összefüggései nemcsak korrelációs és faktoranalízis útján képezték elemzés tárgyát, hanem a vizsgálati személyek csoportosítására is sor került, a nézetek kapcsolódási mintáit kifejező jellegzetes válasznyalábjaik alapján. A klaszteranalízis három népes csoportot különített el, amelyeket toleránsnak, ambivalensnek, illetőleg
hiperkritikus
nak lehet címkézni, és meg lehet határozni helyüket a közállapotok (alapvetően kedvezőtlen) megítélésének kontinuumában. Az empirikus adatok arról tanúskodnak, hogy a társadalom érzésvilágát a történeti léptékű társadalmi átalakulás, a társadalmi mobilitás és különbségek növekedése, valamint a társadalmi egyenlőség és gondoskodás normáinak halványulása és keresése zaklatja fel.
Goals, projects, strivings. I. Theoretical considerations and possibilities of application
Authors: Martos Tamás
Published: August 2009

A tanulmány első része bemutatja a célok szerepét a személyiség működésében, valamint áttekinti a célok kutatásának néhány elméleti és gyakorlati vonatkozását. A célok fenomenológiai, funkcionális, személyiség-lélektani és szociálpszichológiai szempontból is jelentősek, segítségükkel írhatók le az emberi működés fontos jellemzői. A célok tanulmányozásához rugalmas és sokoldalú eszközkészlet áll rendelkezésre, melynek elméleti megfontolásai közül a kérdésfeltevés fókuszát, az elméleti keret szükségét, valamint a célrendszer hierarchiájának és a célokhoz kapcsolódó jellemzők kiválasztásának szempontjait elemzem részletesen. Példaként bemutatok három olyan kutatási területet, amelyeken a célok elméletét és módszertanát alkalmazták: 1. az elkerülő és megközelítő tendenciák jelentkezését a célokban, illetve ennek következményeit az egészséges pszichológiai működés szempontjából; 2. az én önmagára vonatkozó céljainak személyiségpszichológiai jelentőségét, valamint 3. a vallásosság és spiritualitás pszichológiájának célalapú megközelítését. A tanulmány első részét a kutatás és gyakorlati alkalmazás további lehetőségeinek tárgyalása zárja.
The concept of Visual Imaginative Synchron and the preliminary results in its operalization
Authors: Varga S. Katalin , Varga Katalin
Published: August 2009

Kutatásunkban az imaginatív tevékenység szinkronizációs folyamatának vizuális modalitását, az interakciós partnerek által átélt Vizuális Imaginatív Szinkront (rövidítve:VIS) vizsgáljuk. A VIS olyan interakciós szinkronjelenség, mely az egymásra hangolódás egy jellegzetes formáját, a képzeleti tevékenység külső megítélő által is azonosítható harmonizációját jelenti. A VIS operacionalizálási folyamata alkalmazható hipnózis és éber szituációkban egyaránt. A Vizuális Imaginatív Szinkron vizsgálatához standardizált eljárás segítségével eltérő dimenziók mentén közepesen szóró verbális motívumokat nyertünk. Az átélt képek közötti esetleges szinkronjelenségek megismeréséhez kialakítottuk a rajz és leírás együttesét alkalmazó VIS tesztet. A standardizált keretek között zajló, egy-másfél órát igénybe vevő éber vizsgálatok során öt vizsgálati motívum kapcsán töltötték ki az interakciós felek a VIS tesztet, illetve a következőket: Képzeleti Tevékenység Kérdőív (VVIQ), Archaikus Bevonódási Skála (ABS), Phenomenology of Consciousness Inventory (PCI), Diádikus Interakciós Harmónia Kérdőív (DIH), Szemekből Olvasás Teszt (SZOT). A diádok (n= 48) VIS tesztjeinek hasonlóság alapján történő megítélésében optimális operacionalizálási eljárásnak a csoportos megítélés bizonyult, ahol minden egyes megítéltetési helyzetről három független megítélő alkotott véleményt, egy helyszínen, egymás választását nem ismerve. A megítélők saját preferenciájuk, személyiségük, beállítódásuk alapján döntöttek. A magas VIS-diád pontszámokat három új független megítélővel retesztben újramértük. A diádok 22,92%-nál találtunk reliábilisan megítélhető szinkront. A validitás vizsgálatok a VIS-nek a PCI Pozitív Érzelmek Alskálájával és a DIH Összhang Alskálájával való összefüggésére utalnak éber interakció esetén. Eredményeink alapján kijelenthetjük, hogy a VIS standardizált éber vizsgálati helyzetben külső megítélők által megbízhatóan azonosítható.
Innovation and group climate: The introduction and validation of the Group Climate Inventory’s Hungarian version
Authors: O. Szabó Orsolya
Published: August 2009

Az innováció napjaink egyik fő fogalmává vált, mint a versenyképesség megőrzésének egyik kulcstényezője. Bár más-más megközelítésből, de az innováció fokozottan foglalkoztatja számos tudományterület elméleti és gyakorlati szakembereit. Tudományterülettől függetlenül állíthatjuk, hogy az innovációval foglalkozó irodalom elsősorban az innovációt elősegítő és serkentő tényezők azonosítására, valamint ezek részletes bemutatására tesz kísérletet. Míg a korai vizsgálatok és elméletek elsősorban a szervezet vagy csoport felépítését és tagjait állították érdeklődésük középpontjába, addig az utóbbi években a hangsúly egyre inkább a szervezeti kultúra és klíma vizsgálatának irányába tolódott. Ezzel párhuzamosan fokozatosan teret nyertek azok a kutatások is, amelyek elemzésük szintjének a munkacsoportot választották a szervezet egésze helyett. Az innovációt elősegítő csoportklíma megragadására West 1990-ben kidolgozta a Négy-faktor elméletet. Az elmélet a következő négy tényezőnek tulajdonít kiemelt szerepet az innovációt elősegítő klíma esetében: vízió, részvételi biztonság, feladatorientáció és az innováció támogatása. A Négy-faktor elmélet alapjainAndersonésWest(1998) később megalkotta a Csoportklíma kérdőívet, amely lehetővé teszi a négy faktor számszerűsítését és mérését. A kérdőív megjelenése óta számos tanulmány foglalkozott annak pszichometriai vizsgálatával, illetve más nyelvekre történő adaptálásával. Jelen tanulmány az elmélet bemutatása után a kérdőív magyar változatát vizsgálja egy harminc munkacsoportból álló mintán. A csoportok mindegyike ugyanahhoz az állami intézményhez tartozik, a mintát a vizsgálatban résztvevő intézmény négy megyei és egy városi intézetének munkatársai alkotják. A teszt megbízhatóságának mérésére Cronbach-alfát számoltunk külön a négy alskálára, illetve a teljes kérdőívre. A magas Cronbach-alfa értékek a kérdőív magyar változatának megbízhatóságára utalnak, azok jóval az elfogadható szint felett vannak. A kérdőív szerkezetének vizsgálatára faktoranalízist végeztünk, melynek eredményei megfelelő szintű illeszkedést mutattak a korábbi, külföldi vizsgálatok jellemzőivel. A kezdeti biztató eredmények alapján a Csoportklíma kérdőív hasznos eszköznek bizonyulhat a magyar elméleti és gyakorlati szakemberek számára is.
The influence of unilateral acceleration on color‐gamut properties of a TFT‐LCD
Authors: Grbec Simon , Diaci Janez
Published: August 2009

Abstract— This letter describes experiments in which a TFT‐LCD was exposed to unilateral acceleration amplitudes of different temporal profiles and durations. The results show that the color gamut is extended by increasing the load amplitude. Following the loading, the color gamut recedes and gradually approaches the reference range.
A dual‐cell‐gap transflective liquid‐crystal display with identical response time in transmissive and reflective regions
Authors: Zhang Jian‐De , Wang Qiong‐Hua , Li Da‐Hai , Yan Jin‐Ren
Published: August 2009

Abstract— A dual‐cell‐gap transflective liquid‐crystal display (TR‐LCD) with identical response time in both the transmissive and reflective regions is demonstrated. In the transmissive region, strong anchoring energy is used to decrease the response time, while in the reflective region, weak anchoring energy is used to increase the response time. And overdrive voltage technology is adopted to make the response time identical in both the transmissive and reflective regions. The device structure and operating principle of the TR‐LCD was analyzed, the anchoring energy in the transmissive and reflective regions was designed, and the response time and electro‐optic characteristics of the TR‐LCD was calculated. The simulated dual‐cell‐gap TR‐LCD demonstrated good performances.
Thin‐film barriers using transparent conducting oxides for organic light‐emitting diodes
Authors: Lee Ho Nyeon , Kim Hyung Jung , Yoon Young Min
Published: August 2009

Abstract— This study covers thin‐film barriers using inorganic barriers of transparent conducting oxides (TCOs) such as zinc oxide (ZnO) and indium tin oxide (ITO). The TCOs were fabricated using a sputtering method with a process gas of pure argon at room temperature. ITO showed better properties as a barrier than the ZnO and exhibited the electronic performance necessary to perform additional functions. The ITO has superior barrier performance because it has a lower crack density due to its partial amorphous phase. For organic/inorganic multilayer barriers, the organic underlayer decreased the water‐vapor transmission rate (WVTR) more than the organic upper layer, indicating that the planarization effect was important in reducing the WVTRs. The results of this organic/ITO multilayer barrier study are expected to be useful in finding a practical solution to OLED encapsulation.
Fabrication of IZO transparent conducting thin films by the use of magnetron sputtering equipped with ion‐beam system
Authors: Jung Jae‐Hye , Lee Se‐Jong , Hwang Hyeon Seok , Baik Hong Koo , Cho Nam‐Ihn
Published: August 2009

Abstract— Indium zinc oxide (IZO) thin films have been prepared on glass, polycarbonate (PC), and polyethylene terephthalate (PET) substrates by using a radio‐frequency (RF) magnetron sputtering system equipped with an ion gun, and a simple OLED device was made by using IZO film. The influence of the RF power, the Ar gas volume, and the substrate temperature during the deposition process on the roughness and the electrical and optical properties of the films have been investigated. In addition, End‐Hall ion‐beam treatment of the substrates is applied before the sputtering deposition process. The sheet resistance of the IZO films is 25 Ω/□ for the glass, 21 Ω/□ for the PC, and 20 Ω/□ for the PET substrate with a thickness of 150 nm, and the lowest root‐mean‐square (rms) roughness of these IZO films were measured to be 0.58, 0.35, and 0.32 nm for glass, PC, and PET substrate, respectively. The decrease in the sheet resistance of the IZO films becomes evident after the ion‐beam treatment and makes the surface of the thin film more hydrophilic. Relative to non‐treated IZO film, the ion‐beam‐treated IZO anode in the OLED device seems to inject holes into the emitting layer to enhance the current density.
Zinc oxide by ALD for thin‐film‐transistor application
Authors: Choi Woon‐Seop
Published: August 2009

Abstract— High‐quality ZnO thin films for transparent thin‐film transistors (TFTs) were successfully prepared by using an injection‐type source delivery system for atomic layer deposition (ALD). By using this delivery system, the source delivery pulse time was dramatically reduced to 0.002 sec to minimize processing time. The growth of ZnO thin film at a relatively low temperature of 150°C shows good characteristics. The process factors on the reactants for film growth were characterized. The bottom‐contact bottom‐gate ZnO TFT shows good electrical properties with solid saturation.
Occupational Exposures Obtained by Questionnaire in Clinical Practice and Their Association With Semen Quality
Authors: de Fleurian Gwendoline , Perrin Jeanne , Ecochard René , Dantony Emmanuelle , Lanteaume André , Achard Vincent , Grillo Jean‐Marie , Guichaoua Marie‐Roberte , Botta Alain , Sari‐Minodier Iréne
Published: August 2009

ABSTRACT: In industrial countries, evidence suggests that semen quality has been steadily decreasing over the past 5 decades. We employed a short questionnaire to examine the association between self‐reported physical or chemical occupational exposures and semen quality. The study included 402 men consulting for couple infertility (314 with oligospermia, asthenospermia, or teratospermia and 88 with normal semen; World Health Organization criteria). Exposure effects on global sperm quality and total sperm count, sperm motility, and sperm morphology were investigated. We found significant associations between semen impairment and occupational risk factors such as exposure to heavy metals (adjusted odds ratio [OR] = 5.4; 95% confidence interval [CI], 1.6–18.1), solvents (OR = 2.5; 95% CI, 1.4–4.4), fumes (OR = 1.9; 95% CI, 1.1–3.4), and polycyclic aromatic hydrocarbons (OR = 1.9; 95% CI, 1.1–3.5). Exposure to pesticides or cement was nearly significant (OR = 3.6; 95% CI, 0.8–15.8, and OR = 2.5; 95% CI, 0.95–6.5, respectively). Physical risk factors were associated with some sperm anomalies, such as mechanical vibrations with oligospermia and teratospermia as well as excess heat and extended sitting periods with impaired motility. Exposure to ionizing radiation and electromagnetic fields was not associated with semen impairment; these results, however, may be skewed, because very few subjects reported such exposure. Despite the small dataset, self‐reported exposures were correlated with semen impairment. This approach may be recommended in routine clinical practice to seek relationships between occupational exposures to reprotoxic agents and impaired semen parameters. This knowledge would allow preventive measures in the workplace to be established and could be complemented by the use of biomarkers to better characterize exposure to chemical substances and their spermiotoxic effects.
The Use of Immunofluorescence in Microdissection Testicular Sperm Extraction
Authors: Greenhalgh Jason R. , Griffith Thomas S. , Wald Moshe
Published: August 2009

ABSTRACT: Microdissection testicular sperm extraction (TESE) has been used in the treatment of male infertility in cases of nonobstructive azoospermia (NOA). In some NOA cases, there is significant difficulty identifying sperm within the testes, and we propose that an immunofluorescence technique may assist in locating sperm foci for use in in vitro fertilization and intracytoplasmic sperm injection. The purpose of this study was to evaluate the feasibility of this novel technique. Thirteen fertile and 8 sterile mice were anesthetized, and a lower abdominal incision was performed to deliver the testes. Then a small incision was made into the tunica albuginea near the vascular pedicle to expose the seminiferous tubules. A microinjector fitted with a micropipette was used to inject fluorescein isothiocyanate—conjugated mouse anti‐human acrosomal IgM antibody (HS‐14) into adjacent injection sites along the exposed seminiferous tubules. Following antibody injection, the testes were examined under a Bio‐Rad Multiphoton microscope to locate sperm through visualization of fluorescence. Sperm were identified in 22 of 26 testes from fertile mice either by morphologic appearance or by their motility, which was obvious under direct visualization. There was strong binding of the antibody to both the sperm head and tail. In contrast, no sperm were visualized in the sterile mice group. Use of an immunofluorescence technique during microdissection TESE for detection of sperm is a novel and feasible concept. Further studies of this technique are planned.
Hormonal Regulation of Total Antioxidant Capacity in Seminal Plasma
Authors: Mancini Antonio , Festa Roberto , Silvestrini Andrea , Nicolotti Nicola , Di Donna Vincenzo , la Torre Giuseppe , Pontecorvi Alfredo , Meucci Elisabetta
Published: August 2009

ABSTRACT: Infertility is associated with oxidative stress, normally counterbalanced by different antioxidant systems. In order to explore the hormonal control of seminal plasma total antioxidant capacity (TAC) we evaluated TAC and hormone patterns in a group of unselected infertile patients and control subjects. One hundred and ten infertile patients (divided into 3 groups: inflammation, varicocele, and other etiologies) and 31 fertile men were examined, evaluating blood serum gonadotropins, testosterone, estradiol, free tri‐iodothyronine, free tetraiodothyronine (FT4), thyrotropin, prolactin (PRL), seminal parameters, and TAC. TAC was measured using the H2O2‐metmyoglobin system, which generates the spectroscopically detectable radical cation of the chromogenous compound 2,2I‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonate). The “lag time” of its appearance is proportional to the antioxidant activity. Lag phase was significantly higher in varicocele vs controls, whereas it was lower in patients with inflammation vs varicocele or other kinds of infertility. The correlation analysis between hormones and seminal parameters showed an inverse correlation between PRL and sperm motility, and a direct correlation of TAC with PRL and FT4, but not with gonadotropins or gonadal steroids. Our data suggest that systemic hormones may play a role in regulating seminal antioxidant capacity. This is interesting also because some hormones, such as thyroid and pituitary hormones, are not usually tested in the first‐level evaluation of male patients with fertility problems.
Body Fat Content and Testosterone Pharmacokinetics Determine Gonadotropin Suppression After Intramuscular Injections of Testosterone Preparations in Normal Men
Authors: Kornmann Britta , Nieschlag Eberhard , Zitzmann Michael , Gromoll Jörg , Simoni Manuela , vo Eckardstein Sigrid
Published: August 2009

ABSTRACT: Interindividual differences in gonadotropin suppression achieved by short‐ and long‐acting intramuscular testosterone (T) preparations were studied to detect factors hindering complete suppression of gonadotropins as the prerequisites for effective male contraception. Forty healthy men received a single injection of T propionate; 4 weeks later they received 2 injections of 1000 mg of T undecanoate (TU) given 6 weeks apart. Following TU, declines of luteinizing hormone (LH) and follicle‐stimulating hormone (FSH) levels were consistent in 17.5% and almost absent in 25% of men. Men showing the most rapid and consistent declines in LH and FSH levels received a slightly higher dose per body weight of TU (13.1 ± 0.6 vs 11.3 ± 0.6 mg/kg; P = NS) and reached higher maximal concentrations of total T (40 ± 4.8 vs 18.4 ± 2.4 nmol/L; P < .001) and free T as well as estradiol. Men with high fat mass (mean ± SEM, 10.3 ± 1.5 vs 23.2 ± 6.4 kg) had a delayed increase in T levels and an impaired relative decline in LH (12 ± 2% vs 53 ± 10%) and FSH (17 ± 6%. vs 70 ± 25%) levels within the first 2 weeks after the first TU injection. We conclude that overweight reduces the chance of rapid and profound gonadotropin suppression during treatment with TU. Body weight needs to be considered to avoid failure of hormonal male contraception.
High Cholesterol Content and Decreased Membrane Fluidity in Human Spermatozoa Are Associated With Protein Tyrosine Phosphorylation and Functional Deficiencies
Authors: Buffone Mariano G. , Verstraeten Sandra V. , Calamera Juan C. , Doncel Gustavo F.
Published: August 2009

ABSTRACT: Poor‐quality sperm show reduced capacity to undergo capacitation‐induced protein tyrosine phosphorylation and hyperactivation. Given that these deficiencies can be overcome by membrane‐permeant stimulators of the cAMP‐dependent kinase system, we hypothesize that the main defect underlying these deficiencies resides on the sperm plasma membrane. Spermatozoa from semen samples obtained from 15 consenting healthy donors were separated in 2 subpopulations, L45 (first interface) and L90 (pellet), using a 45:65:90 ISolate gradient centrifugation method. These sperm fractions were studied before and after a 6‐hour capacitating incubation for sperm motion parameters (computer‐assisted analysis), including hyperactivation, protein tyrosine phosphorylation (immunofluorescence), membrane fluidity (Laurdan fluorescence), and sterol and phospholipid content (high‐performance thin‐layer chromatography). In summary, data indicate that L45 (poor‐motility) spermatozoa present an excess of cholesterol and desmosterol, which impairs the normal increase in membrane fluidity during capacitation and its consequent activation of protein tyrosine phosphorylation and hypermotility. Therefore, a defect in membrane composition and dynamics is underlying human sperm biochemical and functional deficiencies related to inadequate capacitation.
Estrogen Sulfotransferase Is Highly Expressed Along the Bovine Epididymis and Is Secreted Into the Intraluminal Environment
Authors: Frenette Gilles , Leclerc Pierre , D'amours Olivier , Sullivan Robert
Published: August 2009

ABSTRACT: Estrogen is found in high concentrations in the excurrent duct, where it regulates the expression of genes involved in water reabsorption. Estrogen sulfotransferase (EST) is a cytosolic enzyme that catalyzes specific sulfonation with a high affinity for estrogens. Because sulfated estrogens do not bind to estrogen receptors, they are considered to be hormonally inactive. EST may thus determine where along the male tract estrogenic environment predominates. Sulfotransferase activity increases along the epididymis and may also play a role in sperm physiology during the epididymal transit. Using a bovine model, we investigated the distribution of EST along the excurrent duct and the possibility that sterols associated with spermatozoa can be substrates of this enzyme. Reverse transcription polymerase chain reactions showed that mRNA encoding EST was expressed in the testis and all along the epididymis. A highly specific antiserum was raised against the bovine recombinant EST and used in Western blots and immunohistologic studies. Western blots of tissue homogenates showed that EST was localized all along the excurrent duct with a higher signal in the caput and corpus epididymidis. EST was detectable in the intraluminal compartment only in the caput epididymidis, where it was associated with epididymosomes and spermatozoa. EST was undetectable in different fractions of fluids collected in the cauda segment. In immunohistologic studies, EST was restricted to the acrosomal region of the caput, but not the cauda epididymal spermatozoa, and detectable in the cytoplasm of the epithelium bordering the lumen all along the epididymis as well as in the rete testis and vas efferens. This enzyme was also associated with the nucleus in the caput and corpus as well as with the apical membrane of the corpus epididymal epithelium. When recombinant EST was incubated in vitro in the presence of caput and cauda spermatozoa, it was able to add sulfate to sperm membrane cholesterol. Our study shows that EST is present in both the intracellular and intraluminal compartments of the epididymis, suggesting that this enzyme plays different roles along the excurrent duct.
Characterization of Erectile Function in Monocrotaline‐Treated Pulmonary Hypertensive Rats
Authors: Gur Serap , Kadowitz Philip J. , Thammasitboon Supat , Lasky Joseph A. , Hellstrom Wayne J. G.
Published: August 2009

ABSTRACT: The aim of this study was to evaluate erectile function in monocrotaline (MCT)–treated rats with pulmonary hypertension (PH). Forty rats were divided into control (n = 20) and MCT‐treated (n = 20) groups. Rats were treated with MCT (60 mg/kg subcutaneously) for 3 weeks to induce PH. Mean pulmonary arterial pressure (mPAP), medial hypertrophy index (percentage of wall thickness of pulmonary artery), and right ventricular hypertrophy (ratio of right ventricle [RV] to left ventricle + septum weight) were evaluated. In vivo erectile responses were assessed by measurement of intracavernosal pressure (ICP)/mean arterial pressure and total ICP (area under the curve). In vitro organ bath studies with corpus cavernosum smooth muscle strips were performed under both normoxic (95% O2/5% CO2) and hypoxic (by changing gas mixture to 95% N2/5% CO2) conditions. Erectile tissue was processed for immunohistochemistry. The MCT‐treated group was associated with an increase in mPAP, medial hypertrophy index, and RV hypertrophy. MCT‐induced PH rats had significantly reduced erectile responses compared with controls. Nitrergic, endothelium‐dependent relaxations, as well as α‐adrenergic contractile responses were significantly reduced in the corpus cavernosum of MCT rats. The functional responses during prolonged periods of hypoxia were similar to those observed in MCT‐treated tissues. PH rats showed enhanced inducible nitric oxide synthase (NOS) protein localization, but endothelial NOS and neuronal NOS were unchanged. These results suggest changes in cavernosal physiology are caused by MCT acting on the penile tissues and the systemic vasculature.
Selenium Supplementation Does Not Affect Testicular Selenium Status or Semen Quality in North American Men
Authors: Hawkes Wayne Chris , Alkan Zeynep , Wong Kenneth
Published: August 2009

ABSTRACT: Selenium (Se) is essential for sperm function and male fertility, but high Se intake has been associated with impaired semen quality. We reported previously a decrease in sperm motility in men fed high‐Se foods, but we could not rule out the influence of other environmental and dietary factors. We now report on a randomized, controlled study on the potential adverse effects of Se supplementation on semen quality in 42 free‐living men administered Se (300 μg/d) as high‐Se yeast for 48 weeks. Semen analysis was performed 4 times before treatment began, then twice each week during treatment at 6, 12, 24, 36, and 48 weeks, and then after treatment at 72 and 96 weeks. Blood samples were collected 3 times before treatment and at each subsequent visit. Se concentration increased 61% in blood plasma and 49% in seminal plasma. However, Se supplementation had no effect on sperm Se, serum androgen concentrations, or sperm count, motility, progressive velocity, or morphology. We observed progressive decreases in serum luteinizing hormone, semen volume, and sperm Se in both the high‐Se and placebo groups. Moreover, sperm straight‐line velocity and percent normal morphology increased in Se‐treated and placebo‐treated participants. The lack of an increase in sperm Se suggests that testicular Se stores were unaffected, even though the participants' dietary Se intake was tripled and their total body Se approximately doubled by supplementation. These results are consistent with animal studies showing the Se status of testes to be unresponsive to dietary Se intake.
The Dark Side of Testosterone Deficiency: III. Cardiovascular Disease
Authors: Traish Abdulmaged M. , Saad Farid , Feeley Robert J. , Guay Andre
Published: August 2009

ABSTRACT:A considerable body of evidence exists suggesting that androgen deficiency contributes to the onset, progression, or both of cardiovascular disease (CVD). The aim of this review is to evaluate the relationships between testosterone (T) deficiency and risk factors of CVD and to discuss the implications of androgen deficiency in men with cardiovascular risk factors. The relationship between androgen deficiency and endothelial function, lipid profiles, inflammatory responses, altered vascular smooth muscle reactivity, and hypertension are discussed with regard to CVD. A comprehensive literature search was carried out with the use of Pub Med from 1980 through 2009, and relevant articles pertinent to androgen deficiency and vascular disease were evaluated and discussed. Low T, whether attributed to hypogonadism or androgen deprivation therapy, in men with prostate carcinoma, produces adverse effects on cardiovascular health. Androgen deficiency is associated with increased levels of total cholesterol, low‐density lipoprotein, increased production of proinflammatory factors, and increased thickness of the arterial wall and contributes to endothelial dysfunction. Testosterone supplementation restores arterial vasoreactivity; reduces proinflammatory cytokines, total cholesterol, and triglyceride levels; and improves endothelial function but also might reduce high‐density lipoprotein levels. Testosterone is an anabolic hormone with a wide range of beneficial effects on men's health. The therapeutic role of T in men's health, however, remains a hotly debated issue for a number of reasons, including the purported risk of prostate cancer. In view of the emerging evidence suggesting that androgen deficiency is a risk factor for CVD, androgen replacement therapy could potentially reduce CVD risk in hypogonadal men. It should be emphasized, however, that androgen replacement therapy should be done with very thorough and careful monitoring for prostate diseases.
Cellular and Regional Distributions of Ubiquitin‐Proteasome and Endocytotic Pathway Components in the Epithelium of Rat Efferent Ductules and Initial Segment of the Epididymis
Authors: Oliveira Cleida A. , Victor‐Costa Anna Bolivar , Hess Rex A.
Published: August 2009

ABSTRACT:Efferent ductules of the male reproductive tract contain high concentrations of estrogen receptors (ER), which are essential for the regulation of fluid reabsorption and maintenance of normal epithelial morphology. Treatments with the antiestrogen ICI 182,780 and 17β‐estradiol cause a reduction in ERα expression; however, the mechanisms governing the down‐regulation are undetermined. In other tissues, the ubiquitin‐proteasome pathway appears to have a dominant role in regulating ERα turnover, although in the efferent ductules, an abundance of epithelial lysosomes could also participate in protein turnover. To study this activity, the expressions of proteasome, ubiquitin, and markers for the endocytotic apparatus (early endosome antigen‐1 [EEA1], clusterin, and cathepsin D) were examined in rat efferent ductules and initial segment of epididymis. Distinct cellular, subcellular, and regional distributions of these proteins were observed in the epithelial cells. A gradient of proteasome, ubiquitin, EEA1, and clusterin staining was seen in the efferent ducts, which decreased 30%–41% from the proximal zone to the terminal common duct. Antiestrogen treatment resulted in significant decreases in proteasome, EEA1, and clusterin in the efferent ducts. Localization of ubiquitin‐proteasome and endocytotic pathway components suggests that differential regulation is required for protein degradation and turnover in efferent ductules and head of the epididymis.
Normal Responses to Restraint Stress in Mice Lacking the Gene for Neuronal Nitric Oxide Synthase
Authors: Weissman Ben A. , Sottas Chantal M. , Holmes Michael , Zhou Ping , Iadecola Costantino , Hardy Dianne O. , Ge Ren‐Shan , Hardy Matthew P.
Published: August 2009

ABSTRACT: The hormonal changes associated with immobilization stress (IMO) include a swift increase in corticosterone (CORT) concentration and a decrease in circulating testosterone (T) levels. There is evidence that the production of the short‐lived neuromodulator nitric oxide (NO) is increased during stress in various tissues, including the brain. NO also suppresses the biosynthesis of T. Both the inducible and the neuronal isoforms of NO synthase (iNOS and nNOS, respectively) have been implicated in this suppression, but the evidence has not been conclusive. We used adult wild‐type (WT) and nNOS knockout male mice (nNOS−/−) to assess the respective roles of CORT and nNOS‐derived NO in stress mediated inhibition of T production. Animals were assigned to either basal control or 3‐hour IMO groups. No difference in basal plasma and testicular T levels were observed between WT and nNOS–/–, although testicular weights of mutant mice were slightly lower compared to WT animals. The plasma contents of luteinizing hormone (LH) and CORT in unstressed mice of both genotypes were similar. Exposure to 3 hours of IMO increased plasma CORT and decreased T concentrations in mice of both genotypes. However, comparable levels of plasma LH and testicular nitrite and nitrate (NOx), NO stable metabolites, were detected in control and stressed WT and nNOS–/– mice. Adrenal concentrations of NOx declined after IMO, but the reduction was not statistically significant. These findings implicate CORT rather than NO generated by nNOS in the rapid stress‐induced suppression of circulating T.
Independent Spatial and Temporal Functions of Human Sperm Centrosomes After Dispermic Microinjection Into Bovine Oocytes
Authors: Terada Yukihiro , Hasegawa Hisataka , Ugajin Tomohisa , Nabeshima Hiroshi , Suzuki Kichiya , Yaegashi Nobuo , Okamura Kunihiro
Published: August 2009

ABSTRACT: During mammalian fertilization, a centrosome is introduced by the sperm during the first cell cycle to organize a radial array of microtubules known as the sperm aster. In nature, multiple human sperm centrosomes may exist in the same egg cytoplasm during polyspermy. However, critical information concerning individual sperm centrosomal function with regards to the latter case remains unknown. We subsequently examined the sperm aster formation after injection of multiple human sperm into a bovine egg. When 2 fertile human sperm were simultaneously microinjected into different regions of the same bovine egg cytoplasm, no difference in sperm aster formation rate was observed compared to cases in which a single sperm was injected. Two human sperm were also microinjected into bovine eggs 30‐, 60‐ and 120‐minute intervals apart from one another, and no difference in sperm aster formation rates were observed. Among eggs in which 1 sperm aster was organized, there was no observable bias towards the first or second injected sperm. These findings indicated that when multiple human sperm are present in a single egg cytoplasm, each centrosome can function independently from the other. This fact suggests the possibility of transplanting a normal sperm centrosome into an egg with a sperm known to have centrosomal dysfunction.
The Dynamics of Collective Reputation
Authors: Levin Jonathan
Published: August 2009

I present a stochastic version of Tirole's (1996) collective reputation model. In equilibrium, group behavior is persistent due to complementarity between the current incentives of group members and the group's reputation, which depends on its history. A group can maintain a strong reputation even as conditions become unfavorable, but an improvement in the environment may not help a group with a poor reputation. I also connect the model to the theory of statistical discrimination and show that the same mechanism can explain why discrimination might persist over time.
Competition Law as Development Policy: Evidence from Poland
Authors: Rajabiun Reza
Published: August 2009

The relationship between the design of competition laws and economic outcomes remains the subject of considerable controversy in both law and economics. Recent cross-national studies suggest that effective legal constraints against anticompetitive practices can enhance prospects for economic development by increasing the number of market participants and the quality of broader political and economic institutions. This paper explores the linkages between regulatory constraints against anticompetitive practices and the efficiency of market mechanisms by focusing on the experience in Poland between the collapse of central planning and regulatory harmonization pursuant to European Union accession. The analysis suggests that per se prohibitions and a narrow bureaucratic mandate provided relatively credible and predictable constraints against anticompetitive agreements and practices during the formative days of the market system in Poland. The evidence has implications for other jurisdictions that instead implement the rule-of-reason approach to the design of competition law during the 1980s and 1990s.
Discrimination of GalNAc (4S/6S) sulfation sites in chondroitin sulfate disaccharides by chip-based nanoelectrospray multistage mass spectrometry
Authors: Flangea Corina , Serb Alina , Schiopu Catalin , Tudor Sorin , Sisu Eugen , Seidler Daniela , Zamfir Alina
Published: August 2009

Sulfation pattern within chondroitin sulfate (CS) glycosaminoglycan (GAG) chains is an important post-translational modification that regulates their interaction with proteins. In this context, development of highly efficient and reproducible analytical methods for the investigation of CS sulfation patterns is of high necessity. In this study we report a novel method for straightforward determination of N-acetylgalactosamine (GalNAc) sulfation sites in chondroitin sulfate disaccharides. Our protocol involves combining fully automated chip-based nanoelectrospray (nanoESI) for analyte infusion and ionization in negative ion mode with multistage (MSn) collision-induced dissociation (CID) high capacity ion trap (HCT) mass spectrometry for generation of sequence ions diagnostic for identification of sulfate ester group position within GalNAc residues. The feasibility of this approach is here demonstrated on chondroitin 6-O-sulfate and chondroitin 4-O-sulfate disaccharides. Fragmentation patterns obtained by MS2 and MS3 sequencing stages provided first mass spectrometric data from which sulfation site(s) within GalNAc monosaccharide ring could be unequivocally deciphered. Hence, the method allowed discriminating 4S/6S sulfation sites solely on the basis of MS and multistage MS evidence.
Conservation of wetlands in Nepal: potential and constraints
Authors: Editor The
Published: August 2009

doi: 10.3126/banko.v19i3.2204Banko Janakari, Special Issue February 2009, 1-3