bluuebunny/crossref_metadata_2025 huggingface dataset:
On the number of representations of positive integers by quadratic forms as the basis of the space S4(Γ0(47), 1)
Authors: Tekcan Ahmet , Bızım Osman
Published: March 2004

The number of representations of positive integers by quadratic
forms and
of discriminant −47 are
given. Moreover, a basis for the space S4(Γ0(47), 1)

are constructed, and the formulas for r(n; F4), r(n; G4),
r(n; F3 ⊕ G1), r(n; F2 ⊕ G2), and
r(n; F1 ⊕ G3) are derived.
q‐Riemann zeta function
Authors: Kim Taekyun
Published: March 2004

We consider the modified q‐analogue of Riemann zeta function
which is defined by
, 0 < q < 1, s ∈ ℂ. In this paper, we give q‐Bernoulli numbers
which can be viewed as interpolation of the above q‐analogue of
Riemann zeta function at negative integers in the same way that
Riemann zeta function interpolates Bernoulli numbers at negative
integers. Also, we will treat some identities of q‐Bernoulli
numbers using nonarchimedean q‐integration.
Lower bounds for eigenvalues of the one‐dimensional p‐Laplacian
Authors: Pinasco Juan Pablo
Published: March 2004

We present sharp lower bounds for eigenvalues of the one‐dimensional p‐Laplace operator. The method of proof is rather elementary, based on a suitable generalization of the Lyapunov inequality.
Species survival versus eigenvalues
Authors: de Santana Luiz Antonio Ribeiro , Bozhkov Yuri Dimitrov , Ferreira Wilson Castro
Published: March 2004

Mathematical models describing the behavior of hypothetical species in spatially heterogeneous environments are discussed and analyzed using the fibering method devised and developed by S. I. Pohozaev.
An elliptic problem with critical exponent and positive Hardy potential
Authors: Chen Shaowei , Li Shujie
Published: March 2004

We give the existence result and the vanishing order of the solution in 0 for the following equation: −Δu(x) + (μ/|x|2)u(x) = λu(x) + u2*−1(x), where x ∈ B1, μ > 0, and the potential μ/|x|2 − λ is positive in B1.
Contractive projections in Orlicz sequence spaces
Authors: Randrianantoanina Beata
Published: March 2004

We characterize norm‐one complemented subspaces of Orlicz sequence spaces ℓM equipped with either Luxemburg or Orlicz norm, provided that the Orlicz function M is sufficiently smooth and sufficiently different from the square function. We measure smoothness of M using AC1 and AC2 classes introduced by Maleev and Troyanski in 1991, and the condition for M to be different from a square function is essentially a requirement that the second derivative M″ of M cannot have a finite nonzero limit at zero. This paper treats the real case; the complex case follows from previously known results.
Hyperbolic differential‐operator equations on a whole axis
Authors: Yakubov Yakov
Published: March 2004

We give an abstract interpretation of initial boundary value problems for hyperbolic equations such that a part of initial boundary value conditions contains also a differentiation on the time t of the same order as equations. The case of stable solutions of abstract hyperbolic equations is treated. Then we show applications of obtained abstract results to hyperbolic differential equations which, in particular, may represent the longitudinal displacements of an inhomogeneous rod under the action of forces at the two ends which are proportional to the acceleration.
Effects of Mechanical Forces and Mediators of Hypertrophy on Remodeling of Gap Junctions in the Heart
Authors: Saffitz Jeffrey E. , Kléber André G.
Published: March 2004

This review article focuses on remodeling of gap junctions in response to chemical mediators of ventricular hypertrophy, mechanical forces, and alterations in cell-to-cell adhesion. Signaling mediated by mechanical forces is likely to be involved in the upregulation of cardiac gap junctions during the early phase of cardiac hypertrophy and the subsequent downregulation in cardiac failure. Several signaling pathways involving cAMP, angiotensin II, transforming growth factor-β, vascular endothelial growth factor, and integrin-mediated regulators have been shown to affect expression of gap junction proteins. However, a comprehensive view of regulation of gap junction trafficking, synthesis, and degradation is still lacking. In addition to gap junction regulation by extracellular mechanical forces, there is a close relation between gap junctions and adhesion junctions and their linkage to the cytoskeleton. This can be inferred from experiments on neoformation of cell-to-cell coupling, concomitant upregulation of adherens and gap junctions after mechanical stretch, and human cardiomyopathies caused by genetic defects in cell-cell adhesion junction proteins. The molecular mechanisms responsible for the interaction between mechanical and functional cell-to-cell coupling remain to be elucidated.
Telomeres and Cardiovascular Disease
Authors: Serrano Antonio L. , Andrés Vicente
Published: March 2004

Telomeres—the specialized DNA-protein structures at the ends of eukaryotic chromosomes—are essential for maintaining genome stability and integrity and for extended proliferative life span in both cultured cells and in the whole organism. Telomerase and additional telomere-associated proteins are necessary for preserving telomeric DNA length. Age-dependent telomere shortening in most somatic cells, including vascular endothelial cells, smooth muscle cells, and cardiomyocytes, is thought to impair cellular function and viability of the aged organism. Telomere dysfunction is emerging as an important factor in the pathogenesis of hypertension, atherosclerosis, and heart failure. In this Review, we discuss present studies on telomeres and telomere-associated proteins in cardiovascular pathobiology and their implications for therapeutics.
The prevalence of rectal chlamydial infection amongst men who have sex with men attending the genitourinary medicine clinic in Edinburgh
Authors: Manavi K , McMillan A , Young H
Published: March 2004

Little is known about the prevalence of rectal chlamydial infection amongst men who have sex with men (MSM). Previous studies using culture methods reported this to be between 4-6%. The emergence of nucleic acid amplification tests has significantly increased the sensitivity and specificity for chlamydial detection, making it possible to estimate the prevalence of rectal infection more accurately.

A prospective cross sectional study involving 443 MSM who were screened for sexually transmitted infections (STIs) between May 1999 and January 2002. Rectal swabs for chlamydiae were obtained in addition to specimens for routine STI screening. Rectal chlamydiae were detected by ligase chain reaction (LCR) utilizing the Abbott LCX Amplicor with confirmation by COBASE amplicor for the majority of cases. Those with rectal chlamydial infection were treated with azithromycin. The characteristics of men with rectal chlamydial infection were compared with those who were not infected at this site.

Rectal chlamydia was detected in 32 (7.2%) of 443 patients. Those with rectal chlamydial infection were more likely to have rectal symptoms (12/32) or having a partner with confirmed chlamydial (2/32) or gonococcal (3/32) urethritis than those MSM without rectal chlamydial infection. They were also more likely to have a history of receptive anal sex (25/32) in the previous three months compared to those MSM without rectal chlamydial infection (263/411). The most common symptoms of patients with rectal chlamydial infection were pruritus ani and peri-anal pain. Eight (25%) of those with rectal chlamydial infection were known to be HIV seropositive.

Rectal chlamydial infection is common amongst MSM and is effectively diagnosed by LCR. The test should be included in the routine STI screening offered to MSM.
General practitioners and the National Strategy on Sexual Health and HIV
Authors: Rogstad K E , Henton L
Published: March 2004

To determine general practitioners' knowledge of, and opinions on, the National Strategy for Sexual Health and HIV and whether they intend to provide Level 1 and 2 HIV/STI services, a self-administered questionnaire was sent to one partner from 155 general practices in Sheffield and North Derbyshire in November 2001. Response rate was 57% (88). Forty-eight (55%) GPs aware of strategy but 53 (60%) had no knowledge of what it involved.

LEVEL 1. Sixty-two (71%) felt confident in providing advice on STI prevention and 46 (52%) on HIV. Nine (10%) GPs provide HIV testing and 29 (33%) anticipate doing so but 24 (83%) require staff training and 20 (70%) increased funding. All Level 1 STI services are provided by 60 (68%) practices and 72 (82%) anticipate providing.

LEVEL 2. Thirty-nine (45%) anticipate testing and treating STIs but only nine (10%) will undertake partner notification. Resources required are training, nine (60%) and funding, nine (60%). The main reasons for not offering in the future were too busy 58 (72%) and lack of demand 25 (31%).

Many GPs are unaware of the strategy but most anticipate providing Level 1 STI services. Less than half anticipate offering HIV testing. Although 45% of GPs may provide Level 2 care, it is unlikely to include partner notification. Many GPs are too busy and require extra training and funding. These needs must be addressed if the Strategy is to be implemented.
High resistance to antiretroviral drugs: the Indian experience
Authors: Hira Subhash K , Panchal Kumkum , Parmar Pooja A , Bhatia Vandana P
Published: March 2004

Effective antiretroviral treatment (ART) has significantly reduced the morbidity and mortality among people living with HIV/AIDS. The emergence of drug resistance is the major obstacle to the successful implementation of long-term treatment strategy of HIV disease. Hence, monitoring the resistance to ART is an essential task. The MGM Medical College in Navi Mumbai is the only national facility with the capacity to monitor ART resistance using tissue culture technique. The main objective of the study was to determine the prevalence of primary and secondary resistance between May 1997 and April 2003. Four hundred and sixty viral isolates of 74 individuals were tested for ART resistance using tissue culture-based protocol (McGill University, Canada). These included 287 primary and 173 follow-up viral isolates. Following activation of tissue culture, a panel of 12 antiretroviral drugs in concentrations from 0.038 mg/mL to 0.090 mg/mL was tested. The resistance was determined on the basis of the production of p24 antigen at the end of 72 and 144 hours of incubation. The overall resistance against reverse transcriptase inhibitors (RTIs) was 33.7% and that to protease inhibitors (PIs) was 21.5%. However, prevalence of primary resistance among ART naïve to RTIs was 14/208 (6.7%) of isolates and that to (PIs) was 2/79(2.5%) of isolates. The incidence of resistance to RTI was 22/500 years (4.4/100 years) and that to PIs was 8/253.6 years (3.2/100 years). It is possible that non-B subtypes of HIV-1 that are prevalent in most developing countries are likely to develop resistance rapidly after ART. However, common factors that influence development of resistance such as poor adherence, inadequate 'wild' doses and regimens, and poor monitoring were not validated in the study. Unless active surveillance is instituted, these factors can pose major challenge for the management of people on ART in developing countries.
A 16-year study of HIV seroprevalence and HIV-related diseases in a teaching tertiary care hospital in India
Authors: Arora D R , Gautam Vikas , Sethi Sunil , Arora B
Published: March 2004

A total of 183,912 persons were screened from September 1986 to May 2002 in and around Haryana, out of whom 1178 were reactive (0.64%) for anti-HIV antibodies. The overall incidence of HIV-1 in the seropositive patients was 98.5%, HIV-2 alone was 0.8% and 0.7% had a mixed infection with both HIV-1 and 2. High seropositivity (22.8%) was observed among the relatives of these HIV-positive individuals. The heterosexual route (78%) remained the predominant mode of transmission. Among the jail inmates only one individual out of 1306 (1986 to 1993) was found to be positive. Tuberculosis (46.7%) was the most common opportunistic infection in these seropositive patients. Significant titres of Venereal Disease Research Laboratory tests were observed in 8.8% seropositive patients, 7.9% were positive for hepatitis B surface antigen and only two patients were suffering from chancroid. Forty-six of these HIV-seropositive patients had already died. In order to cope with this epidemic, new models of care and cost-effective preventive measures are needed.
A multi-district audit of the management of syphilis in genitourinary medicine clinics in Yorkshire
Authors: McClean Hugo , Evans Amy ,   on behalf of The Yorkshire Multi-District Genitourinary Medicine Clinical Audit Group
Published: March 2004

An audit against standards and guidelines of a representative sample of syphilis cases managed in genitourinary medicine clinics in Yorkshire was carried out. Satisfactory serological endpoints could be determined for about two-thirds of treated early and less than one-third of treated late syphilis cases. HIV antibody testing was obtained for less than half of all cases. Recently available national guidelines suggest inadequacy of both the dose and duration of treatments with procaine penicillin of asymptomatic late syphilis cases where lumbar puncture was not carried out. The diagnosis and management of syphilis is complex, and this audit demonstrates the importance of the systematic approach developed by genitourinary medicine clinic and laboratory services.
Genitourinary medicine: an opportunity to reduce unwanted pregnancy
Authors: Kingston M A , White C , Carlin E M , Ahmed-Jushuf I H
Published: March 2004

We sought to investigate contraceptive use in women attending a genitourinary medicine (GUM) clinic, and to assess the need for a contraceptive service in this setting. Female attendees at Nottingham GUM clinic were invited to complete an anonymous questionnaire regarding past and present contraceptive use and whether a contraceptive service within GUM would be utilized. Four hundred and eighty-nine questionnaires were analysed. The majority had previously used condoms (89.8%) or the combined oral contraceptive pill (COCP) (74.6%), and 46.6% and 37.4%, respectively were currently using these methods. Contraception was frequently used for the dual aims of avoiding both pregnancy and infection (48.5%). General practitioners (GPs) and family planning clinics were most frequently cited as sources of regular contraceptive advice, 58.1% and 47.2% respectively, and emergency contraception 50.8% and 37.3%, respectively. If a contraceptive service was available within GUM 56.9% of respondents indicated they would use it.
Hepatitis B infection in an HIV-positive man treated with tenofovir: a case of re-infection or reactivation?
Authors: Richardson D , Lamba H
Published: March 2004

We report an HIV-positive man who re-acquires hepatitis B with evidence of serological protection which then resolves while on anti-retrovirals including tenofovir.
Two traditions of interaction research
Authors: Peräkylä Anssi
Published: March 2004

The paper compares Bales' Interaction Process Analysis (IPA) with Sacks' Conversation Analysis (CA), arguing that CA has answered several questions that originally motivated the development of IPA, and while doing so, it has re‐specified the phenomena of interaction research. These two research traditions are in many ways diametrically opposed: the former is quantitative, theory‐oriented and aims at global characterizations of interactional situations, while the latter is qualitative, inductive and aims at characterizing specific layers of organization (such as turn taking or sequence organization) that give structure to interactional situations. Their primary objects of study are different. For the Balesian tradition, it is the functioning and the structure of a small group, whereas in the Sacksian tradition, it is the structures and practices of human social interaction per se. It is argued, however, that CA has radically expanded understanding of the questions IPA was originally developed to address. These questions include allocation of resources, control and solidarity. Bales' research deals with them in terms of the differentiation of participants of a group, whereas CA has re‐specified them as emergent aspects of the very rules and structures that constitute and regulate interaction sequences. The uniqueness of the CA perspective on social interaction is demonstrated by exploring the display of emotion as an interactional phenomenon. It is argued that the display of emotion is intrinsically embedded in the sequential organization of action. Sensitive ‘coding and counting’ approaches can detect emotion displays, but the contribution of CA is to show the specific ways in which they are part of the business of interaction.
Foxes, green fields and Britishness: On the rhetorical construction of place and national identity
Authors: Wallwork Jodi , Dixon John A.
Published: March 2004

This paper explores an accepted but under researched feature of national categories: their complex relationship with social constructions of place. We argue that social psychological work on national identification and mobilization would benefit from closer attention to this relationship. In order to develop this argument, we analyse a series of newspaper accounts published on behalf of the Countryside Alliance, a coalition formed to preserve rural ‘ways of life’ in the UK and, more specifically, to defend extant practices of hunting. Applying a discourse analytic method, we show how the Alliance has exploited the rhetoric of place in order to portray the preservation of hunting as an issue of national significance. By associating British identity with the‘rural idyll’ of the English countryside, the organization has appealed to a place construction in which hunting and its associated activities become cast as essential expressions of the national character. Building on relevant work in geography and discursive psychology, we trace some wider implications of this process for social psychological research on category construction, reification and collective mobilization.
Political identity and the Third Way: Some social‐psychological implications of the current anti‐ideological turn
Authors: Weltman David
Published: March 2004

This paper considers recent large‐scale changes in British politics from the standpoint of a detailed examination of the practical dilemmas, concerning political identity, faced by local politicians in their talk about politics. It seeks to examine the social‐psychological significance of a shift which has meant that politics, while continuing to be characterized by formal division, has begun to extensively reflect the influence of an ideology of anti‐ideology.
Combining individuality and relatedness: Representations of the person among the Anglican clergy
Authors: Vignoles Vivian L. , Chryssochoou Xenia , Breakwell Glynis M.
Published: March 2004

Representations of the person and their significance for identity and action were studied in an interpretative phenomenological analysis of interviews with 42 Anglican clergymen and clergywomen. Participants portrayed the person as having an individual relationship with God and being essentially both unique and related to others; the latter themes supported the coexistence among these participants of both individualistic and relational values, which might be portrayed as either opposing or complementary. The analysis supported theorizing concepts of the person as socially constructed themata with broad implications for identity, values and action, but did not reflect common assumptions in cross‐cultural psychology: cultural orientations vary within as well as between nations, and individualism and collectivism are not necessarily opposites. We argue for a more finely grained approach to the study of culture and personhood.
The psychological conditions of meaningfulness, safety and availability and the engagement of the human spirit at work
Authors: May Douglas R. , Gilson Richard L. , Harter Lynn M.
Published: March 2004

Building on Kahn's (1990) ethnographic work, a field study in a U.S. Midwestern insurance company explored the determinants and mediating effects of three psychological conditions — meaningfulness, safety and availability — on employees' engagement in their work. Results from the revised theoretical framework revealed that all three psychological conditions exhibited significant positive relations with engagement. Meaningfulness displayed the strongest relation. Job enrichment and work role fit were positively linked to psychological meaningfulness. Rewarding co‐worker and supportive supervisor relations were positively associated with psychological safety, whereas adherence to co‐worker norms and self‐consciousness were negatively associated. Psychological availability was positively related to resources available and negatively related to participation in outside activities. Finally, the relations of job enrichment and work role fit with engagement were both fully mediated by the psychological condition of meaningfulness. The association between adherence to co‐worker norms and engagement was partially mediated by psychological safety. Theoretical and practical implications related to psychological engagement at work are discussed.
Organizational citizenship behaviours in relation to job status, job insecurity, organizational commitment and identification, job satisfaction and work values
Authors: Feather N. T. , Rauter Katrin A.
Published: March 2004

This study investigated organizational citizenship behaviours (OCBs) in a sample of 154 school teachers from Victoria, Australia, of whom 101 were in permanent employment and 53 on fixed‐term contracts. Participants completed measures of OCBs, job insecurity, organizational commitment, organizational identification, job satisfaction and work values relating to influence, variety and skill utilization. Results showed that the contract teachers reported more job insecurity and more OCBs compared to the permanent teachers. OCBs were positively related to perceived job insecurity and negatively related to opportunities to satisfy influence and skillutilization work values for the contract teachers, and positively related to organizational commitment, organizational identification and to opportunities to satisfy variety and skill‐utilization work values for the permanent teachers. Results were discussed in relation to the different functions that OCBs were assumed to serve for both groups of teachers and the possibility of conceptualizing OCBs using a motivational analysis that takes account of expectations and goal structures.
A single‐item graphic scale for the measurement of organizational identification
Authors: Shamir Boas , Kark Ronit
Published: March 2004

We offer a single‐item graphic scale for the measurement of identification with organizations and organizational units. The scale is based on conceiving of identification in terms of distance or overlap between entities in a cognitive space. We present results from five samples regarding the reliability and validity of the scale.
Cytokine control in human endometrium
Authors: Kelly RW , King AE , Critchley HO
Published: March 2004

Cytokines within endometrium participate in both menstruation and implantation but also contribute to the defence mechanisms of the mucosal epithelium. Endometrium is under the control of steroid hormones, particularly progesterone and, thus, control of cytokines by this steroid is important. Although appreciable numbers of progesterone receptors are not found in endometrial leucocytes, progesterone can modulate cytokines by acting on uterine cells expressing the receptor. The NFkappaB pathway is important in the control of cytokine synthesis and can modulate production of chemokines, matrix metalloproteinases and the inducible prostaglandin synthesis enzyme COX-2. NFkappaB activity can be inhibited by progesterone by either stimulating synthesis of IkappaB, the molecule that restrains NFkappaB in the cytosol, or after binding to the nuclear receptor, competing with NFkappaB for recognition sites on the relevant gene. In this way, progesterone can limit pro-inflammatory pathways. The major palliatives for endometrial dysfunctions such as menorrhagia and dysmenorrhoea have been the non-steroidal anti-inflammatory drugs that inhibit prostaglandin synthesis. Prostaglandins have major effects on cytokine production but the direct action of prostaglandin E on leucocytes is not a pro-inflammatory response but is to stimulate interleukin 10 and inhibit interleukin 12 synthesis. The likely effect of the non-steroidal anti-inflammatory drugs is on the cells surrounding the small blood vessels, where a synergistic action between prostaglandin and chemokine will induce leucocyte entry and activation leading to lysis of connective tissue and menstruation. At the time of implantation, tight control of cytokine synthesis is required. Although leukaemia inhibitory factor is essential to implantation, the mouse knockout models show that the prostaglandin system is also essential but that there are mutually supportive pathways that compensate for the knockout of many cytokines.
Trophoblast interferon and pregnancy
Authors: Demmers KJ , Derecka K , Flint A
Published: March 2004

The maternal recognition of pregnancy in ruminants requires the production of interferons by the preimplantation blastocyst. These proteins, the trophoblast interferons (IFN-tau), are the products of a number of similar genes, the expression of which is controlled by characteristic promoter regions. They are expressed for a short period in high concentrations, and have antiluteolytic, antiviral, antiproliferative and immunomodulatory effects, through receptors on the endometrial epithelium. The antiluteolytic effects of IFN-tau result from inhibition of endometrial expression of the oxytocin receptor, through which circulating oxytocin stimulates episodic prostaglandin F2a production. Some of the properties of IFN-tau differ from those of other type I interferons, and they may have novel therapeutic effects. Because of their central role in early gestation, these proteins have excited the interest of reproductive physiologists. However, their other properties, and the fact that their expression is controlled so precisely, have made them of interest to a wide range of biologists.
Maturation of human oocytes in vitro and their developmental competence
Authors: Trounson A , Anderiesz C , Jones G
Published: March 2004

Complete maturation of oocytes is essential for the developmental competence of embryos. Any interventions in the growth phase of the oocyte and the follicle in the ovary will affect oocyte maturation, fertilization and subsequent embryo development. Oocyte size is associated with maturation and embryo development in most species examined and this may indicate that a certain size is necessary to initiate the molecular cascade of normal nuclear and cytoplasmic maturation. The minimum size of follicle required for developmental competence in humans is 5-7 mm in diameter. Maturation in vitro can be accomplished in humans, but is associated with a loss of developmental competence unless the oocyte is near completion of its preovulatory growth phase. This loss of developmental competence is associated with the absence of specific proteins in oocytes cultured to metaphase II in vitro. The composition of culture medium used successfully for maturation of human oocytes is surprisingly similar to that originally developed for maturation of oocytes in follicle culture in vitro. The presence of follicle support cells in culture is necessary for the gonadotrophin-mediated response required to mature oocytes in vitro. Gonadotrophin concentration and the sequence of FSH and FSH-LH exposure may be important for human oocytes, particularly those not exposed to the gonadotrophin surge in vivo. More research is needed to describe the molecular and cellular events, the presence of checkpoints and the role of gene expression, translation and protein uptake on completing oocyte maturation in vitro and in vivo. In the meantime, there are very clear applications for maturing oocytes in human reproductive medicine and the success rates achieved in some of these special applications are clinically valuable.
Stage-specific and differential expression of gap junctions in the mouse ovary: connexin-specific roles in follicular regulation
Authors: Wright CS , Becker DL , Lin JS , Warner AE , Hardy K
Published: March 2004

Gap junction communication plays an essential role in follicle growth. Immunocytochemistry and confocal microscopy were used to examine the expression of gap junction connexins of the alpha and beta subfamilies in follicles from primordial to preovulatory stages in the ovaries of prepubertal and adult mice. Connexin-specific antibodies detected alpha(1), alpha(4), alpha(6), beta(1), beta(2) and beta(4) connexins within follicles. In adult ovaries connexin immunolabelling was stronger in larger (more mature) follicles than it was in smaller follicles, with comparatively reduced labelling detected in prepubertal ovaries. In healthy follicles, labelling for alpha subfamily connexins was detected between granulosa cells, whereas labelling for beta subfamily connexins was found in the theca. Labelling for beta subfamily connexins and alpha(4) connexin (preantral stage) was detected on the oocyte surface membrane. In atretic follicles, labelling for beta(4) connexin appeared between the granulosa cells. These results demonstrate that alpha and beta connexin subfamilies are segregated to separate cellular compartments in the mouse follicle. The results are discussed in the light of possible roles for differential gap junctional communication in the regulation of folliculogenesis, oocyte maturation and atresia.
Role of ascorbic acid in promoting follicle integrity and survival in intact mouse ovarian follicles in vitro
Authors: Murray AA , Molinek MD , Baker SJ , Kojima FN , Smith MF , Hillier SG , Spears N
Published: March 2004

Ascorbic acid has three known functions: it is necessary for collagen synthesis, promotes steroidogenesis and acts as an antioxidant. Within the ovary, most studies have concentrated on the role of ascorbic acid in luteal formation and regression and little is known about the function of this vitamin in follicular growth and development. Follicular growth and development were investigated in this study using an individual follicle culture system that allows the growth of follicles from the late preantral stage to Graafian morphology. Follicles were isolated from prepubertal mice and cultured for 6 days. Control media contained serum and human recombinant FSH. Further groups of follicles were cultured in the same media but with the addition of ascorbic acid at concentrations of either 28 or 280 micromol l(-1). Addition of ascorbic acid at the higher concentration significantly increased the percentage of follicles that maintained basement membrane integrity throughout culture (P < 0.001). Ascorbic acid had no effect on the growth of the follicles or on oestradiol production. Metalloproteinase 2 activity tended to increase at the higher concentration of ascorbic acid and there was a significant concomitant increase in the activity of tissue inhibitor of metalloproteinase 1 (P < 0.01). Follicles cultured without the addition of serum but with FSH and selenium in the culture media underwent apoptosis. Addition of ascorbic acid to follicles cultured under serum-free conditions significantly reduced apoptosis (P < 0.05). From these data it is concluded that ascorbic acid is necessary for remodelling the basement membrane during follicular growth and that the ability of follicles to uptake ascorbic acid confers an advantage in terms of granulosa cell survival.
Ovarian autoimmunity in relation to egg production in laying hens
Authors: Barua A , Yoshimura Y
Published: March 2004

The aim of this study was to determine whether anti-ovarian autoantibodies appear in the circulation of laying hens and whether the concentrations of these antibodies change with respect to ageing and egg laying rate. Autoantibodies to ovarian tissues in the circulation of aged (aged approximately 670 days) White Leghorn hens with low (< 50%) and high (> 90%) egg laying rates were examined by ELISA and western blotting. Young laying hens (aged 185 days) with > 95% egg production were used as controls. The results of the ELISA indicated that IgG, which bound to the ovary and small white follicles, was present in the circulation of old laying hens. More hens that laid few eggs had circulatory autoantibodies to the ovary and small white follicles, as determined by the cut-off value in ELISA (mean absorbance + 2 SD of young laying hens), than did hens that laid greater numbers of eggs, and the concentration of IgG was significantly higher in the hens that laid few eggs. In contrast, when the muscle proteins were used as antigens there were no significant differences in the absorbance values among low and high laying frequency old hens or young hens. Western blotting revealed many bands of immunoprecipitates formed by ovarian antigens and antibodies in the serum of old hens, indicating the presence of many binding sites for circulatory IgG in ovarian tissues. These results indicate that antibodies to ovarian tissues appear in the circulation of laying hens during ageing, and that the concentration of these autoantibodies is related inversely to the rate of egg laying by hens.
Inhibition of human and ovine acrosomal enzymes by tannic acid in vitro
Authors: Taitzoglou IA , Tsantarliotou M , Zervos I , Kouretas D , Kokolis NA
Published: March 2004

The effect of tannic acid, a common flavonoid, on the acrosin and plasminogen activator activity and plasmin activity of human and ram spermatozoa was evaluated. Acrosin and plasminogen activator activity were determined by spectrophotometry using the chromogenic substrates N-alpha-benzoyl-DL-arginine para-nitroanilide-HCl (BAPNA) and H-D-valyl-L-leucyl-L-lysine-p-nitroanilide-2HCl (S-2251), respectively. In extracts from both human and ovine acrosomes, the activities of acrosin and plasminogen activators were susceptible to tannic acid inhibition. The inhibitory effect of tannic acid was observed at concentrations > 50 micromol l(-1) in a dose-dependent manner. In additional experiments, low concentrations of tannic acid significantly inhibited tissue-type plasminogen activator, urokinase-type plasminogen activator and plasmin activity in a concentration-dependent manner over the range 0.25-200 micromol l(-1). Tannic acid reduced the motility of ram spermatozoa at a concentration of 1000 micromol l(-1) after 2 and 3 h co-incubation with spermatozoa. The motility of human spermatozoa remained unchanged over the range 0.1-1000 micromol tannic acid l(-1) during 3 h co-incubation. These results indicate that tannic acid inhibited the activity of both acrosin and plasminogen activator and indicates a possible mechanism by which flavonoids exert their antifertility effects.
Ultrasound and endocrine evaluation of the ovarian cycle and early pregnancy in the Sumatran rhinoceros, Dicerorhinus sumatrensis
Authors: Roth TL , O'Brien JK , McRae MA , Bellem AC , Romo SJ , Kroll JL , Brown JL
Published: March 2004

Longitudinal ultrasound and endocrine evaluations were conducted in two adult female Sumatran rhinoceroses (Dicerorhinus sumatrensis) over a period of 12-22 months to learn more about their reproductive physiology. Rectal ultrasonography was conducted to monitor ovarian activity. Blood samples were collected and analysed for progesterone and LH, and faecal samples were analysed for progestin metabolites. One female showed cyclic ovarian activity during the study period, whereas the other female showed no evidence of ovarian activity. The cyclic Sumatran rhinoceros appeared to be an induced ovulator, the first of its kind reported within the Perrisodactyla. Ultrasound examinations of the ovaries revealed the formation of anovulatory haemorrhagic follicles when the animal was not mated. These follicles appeared to undergo varied degrees of luteinization that resulted in irregular faecal progestin profiles. When allowed to mate, the female showed a 21 day reproductive cycle that was reflected in both faecal progestin and serum progesterone profiles. The concentration of serum LH was baseline before mating, increased approximately 30-fold within 1-2 h of intromission and returned to baseline within 22 h. Ovulation occurred within 46 h of copulation. The female conceived three times during the study. Pregnancy was detected using ultrasonography 14-16 days after mating, and the concentration of both serum progesterone and faecal progestins remained high. Early embryogenesis appeared to be similar to that in horses. However, each pregnancy terminated unexpectedly within the first 3 months of gestation. This study demonstrates the important role that basic research and reproductive technology can play in developing a natural breeding programme for an endangered animal in captivity.
Anatomical and histological changes in the oviducts of Japanese quail, Coturnix japonica, after embryonic exposure to ethynyloestradiol
Authors: Berg C , Holm L , Brandt I , Brunstrom B
Published: March 2004

Oestrogen is needed for normal oviductal development in female birds, but excessive early exposure to oestrogen can cause oviductal abnormalities and impair egg-laying ability. In this study, the anatomical and histological effects of in ovo exposure to the synthetic oestrogen ethynyloestradiol on the oviducts of immature and adult female Japanese quail, Coturnix japonica, were investigated. A series of abnormalities was observed after injection of ethynyloestradiol (2 or 20 ng g(-1) egg) into the yolk on day 3 of incubation. Ethynyloestradiol induced precocious differentiation of the luminal epithelium and tubular glands in immature chicks. Right-side oviduct retention occurred at all the ages studied, whereas certain other effects were not evident until sexual maturity. The left oviduct was reduced in size and tubular gland density in the uterus (shell gland) was reduced in sexually mature birds that had been treated with ethynyloestradiol. The utero-vaginal junction was longer than in control birds and had a higher tubular gland density. The epithelial cells in the magnum were taller in birds treated with ethynyloestradiol. Embryonic exposure to the environmental contaminant ethynyloestradiol may cause persisting structural malformations in oviducts of quails, which can impair fertility. As oviductal malformations are indicative of embryonic exposure to exogenous oestrogen, they are potentially useful as biomarkers of xenooestrogen exposure in wild bird populations.
Short-term storage of cane toad (Bufo marinus) gametes
Authors: Browne RK , Clulow J , Mahony M
Published: March 2004

The responses of cane toad (Bufo marinus) gametes, used as a model for the development of assisted reproduction techniques for rare and endangered amphibians, to short-term storage at temperatures > 0 degrees C were studied. Whole excised testes were stored at 0 degrees or 4 degrees C for 15 days, and sperm motility was measured at excision and after storage for 2, 5, 7, 10, 12 and 15 days. Spermatozoa showed > 50% motility for 7 days at 0 degrees C and for 5 days at 4 degrees C. At 15 days, only spermatozoa stored at 0 degrees C still showed some motility (3%). Sperm suspensions were prepared at 5 day intervals over 30 days in simplified amphibian ringer (SAR) at dilutions of 1:1, 1:5 and 1:10 (w/v) testes:SAR. Aliquots from each dilution were stored at 0 degrees C in Eppendorf tubes opened at 5 day intervals of storage (aerated) or kept sealed (unaerated) (treatments: aerated or unaerated; 5, 10, 15, 20, 25 and 30 days storage). After 30 days, sperm motility and fertilizing capacity were determined. The optimal protocol for sperm storage up to 10 days, as assessed by the retention of fertilizing capacity, was as a 1:5 testis:SAR (w/v) suspension, whereas the longest absolute retention of both motility and fertilizing capacity was observed in concentrated (1:1 dilution), anaerobic suspensions (up to 25-30 days). Oviductal oocytes placed in SAR at 5, 10, 15, 20 and 25 degrees C immediately after ovulation lost viability when cooled rapidly to 5 degrees C and stored for 2 h. However, oocytes retained viability for up to 8 h at the optimum storage temperature of 15 degrees C. Thus, it is concluded that during short-term storage spermatozoa retain viability for longer than oocytes, and that spermatozoa in suspensions retain viability for longer than spermatozoa stored in situ in excised testes.
Relationship between maternal endocrine environment, early embryo development and inhibition of the luteolytic mechanism in cows
Authors: Mann GE , Lamming GE
Published: March 2004

In this study, the relationship between maternal hormone environment and early embryo development in mature non-lactating Holstein-Friesian cows was investigated. Animals were inseminated at either 72 or 96 h after prostaglandin injection (n = 23) or were left as uninseminated controls (n = 10). Plasma samples were collected once a day from the first day of insemination (day 1) until day 16, when the cows underwent an oxytocin challenge, and were then slaughtered and their reproductive tracts removed. The tracts were flushed to collect embryos and the flushes were measured for interferon tau (IFN-tau) activity. Inseminated cows without an embryo on day 16 (n = 5) underwent both delayed ovulation (indicated by delayed decrease in oestradiol concentrations) and a delayed increase in progesterone concentrations after ovulation compared with cows with an embryo on day 16 (n = 15). Within the group of cows with an embryo, those with poorly developed embryos producing undetectable concentrations of IFN-tau (n = 7) had similar oestradiol profiles but underwent a delayed progesterone increase after ovulation compared with cows with well developed embryos producing measurable quantities of IFN-tau (n = 8). In the cows with an embryo, the plasma concentration of 13,14-dihydro-15-keto PGF2a, the principal metabolite of PGF2a, after injection of oxytocin was lower than that of control cows and cows without an embryo. However, when the cows with an embryo were compared on the basis of production of embryonic IFN-tau, the PGF2a response to oxytocin was attenuated completely in cows that had measurable IFN-tau activity, whereas a response of similar magnitude to that in control cows and cows without an embryo was observed in those with undetectable IFN-tau activities. In conclusion, the successful maternal recognition of pregnancy in cows depends on the presence of a sufficiently well developed embryo producing sufficient quantities of IFN-tau, which is, in turn, dependent on an appropriate pattern of maternal progesterone secretion.
Human endometrial angiogenesis
Authors: Gargett CE , Rogers PA
Published: March 2004

Angiogenesis is the development of new microvessels from existing vessels, a process that involves microvascular endothelial cells. Physiological angiogenesis rarely occurs in adults except in the ovary and endometrium during the reproductive life of females. Angiogenesis occurs by sprouting and non-sprouting mechanisms. Since endothelial sprouts are not observed in human endometrium, we hypothesized that non-sprouting mechanisms such as intussusception and elongation are involved in endometrial angiogenesis. The demand for angiogenesis differs spatially and temporally in the endometrium: angiogenesis occurs in the basalis layer during menstruation and in the functionalis and subepithelial capillary plexus during the proliferative and early secretory stages. Most studies have failed to demonstrate a link between expression of endometrial angiogenic factors and new vessel growth. However, we demonstrated recently a strong relationship between vascular endothelial growth factor (VEGF) immunolocalized in in-travascular neutrophils and endothelial cell proliferation in each of the subepithelial capillary plexus, functionalis and basalis regions of the human endometrium. Our data also indicate that focal neutrophil VEGF has a role in the development of the subepithelial capillary plexus and functionalis microvessels during the proliferative phase of the menstrual cycle. We propose that neutrophils are an intravascular source of VEGF for vessels that undergo angiogenesis by intussusception and elongation.
Role of androgens and fibroblast growth factors in prostatic development
Authors: Thomson AA
Published: March 2004

This review focuses on the role of androgens and fibroblast growth factors (FGFs) in regulating the growth and development of the prostate. It is known that androgens and mesenchymal-epithelial interactions are required for the formation and growth of the prostate, but little is known of the molecular mediators regulating prostatic organogenesis. Paracrine signalling from the mesenchyme to the epithelium is a key element of prostatic development and the action of androgens in mesenchymal cells is essential for prostatic development. This finding has led to the hypothesis that androgens regulate the expression of paracrine-acting growth factors. Although several families of growth factors play a role in regulating prostatic growth, the FGF family contains members that have been studied most comprehensively in regard to prostatic growth and branching morphogenesis. The role of FGFs in prostatic development is described in detail, since two members of the FGF family function as mesenchymal paracrine-acting factors in the prostate. It has been shown that FGF7 and FGF10 play important roles during prostatic development yet they do not appear to be regulated directly by androgens. Current models propose that growth factor expression (including FGF7 and 10) is regulated directly by androgens. However, it is possible that androgen regulation is indirect and a model outlining indirect androgen regulation of growth factors is proposed.
Potential roles of decidual prolactin in early pregnancy
Authors: Jabbour HN , Critchley HO
Published: March 2004

Successful establishment of pregnancy is dependent on uterine receptivity at the time of trophoblast invasion and implantation. The endometrium undergoes morphological and functional differentiation during the mid- to late secretory phase of the menstrual cycle in preparation for such an event. These changes are orchestrated by ovarian steroid hormones. However, local autocrine-paracrine signalling at the deciduo-placental interface is crucial for successful establishment of pregnancy. One key cytokine that may regulate many functions in implantation is prolactin. Prolactin is secreted by the decidualized endometrium at the time of predicted conception and, in the event of pregnancy, local expression and secretion of prolactin persists until term. Prolactin mediates its effect on target cells through interaction with single-pass transmembrane receptors. Localization of the sites of expression of the prolactin receptor indicates that the cytokine may regulate an array of functions in the pregnant uterus that are crucial in im-plantation and early pregnancy.