bluuebunny/crossref_metadata_2025 huggingface dataset:
Requirement ofabdominal-AandAbdominal-Bin the developing genitalia ofDrosophilabreaks the posterior downregulation rule
Authors: Foronda David , Estrada Beatriz , de Navas Luis , Sánchez-Herrero Ernesto
Published: December 2005

The genitalia of Drosophila derive from the genital disc and require the activity of the Abdominal-B (Abd-B) Hox gene. This gene encodes two different proteins, Abd-B M and Abd-B R. We show here that the embryonic genital disc, like the larval genital disc, is formed by cells from the eighth (A8), ninth (A9) and tenth (A10) abdominal segments,which most likely express the Abd-B M, Abd-B R and Caudal products,respectively. Abd-B m is needed for the development of A8 derivatives such as the external and internal female genitalia, the latter also requiring abdominal-A (abd-A), whereas Abd-B r shapes male genitalia (A9 in males). Although Abd-B r represses Abd-B min the embryo, in at least part of the male A9 such regulation does not occur. In the male A9, some Abd-B m–r– or Abd-B r– clones activate Distal-less and transform part of the genitalia into leg or antenna. In the female A8, many Abd-B m–r– mutant clones produce similar effects, and also downregulate or eliminate abdominal-Aexpression. By contrast, although Abd-B m is the main or only Abd-B transcript present in the female A8, Abd-B m– clones induced in this primordium do not alter Distal-less or abd-A expression, and transform the A8 segment into the A4. The relationship between Abd-B and abd-A in the female genital disc is opposite to that of the embryonic epidermis, and contravenes the rule that posteriorly expressed Hox genes downregulate more anterior ones.
The centrosome-nucleus complex and microtubule organization in theDrosophilaoocyte
Authors: Januschke Jens , Gervais Louis , Gillet Laurent , Keryer Guy , Bornens Michel , Guichet Antoine
Published: December 2005

Molecular motors transport the axis-determining mRNAs oskar,bicoid and gurken along microtubules (MTs) in the Drosophila oocyte. However, it remains unclear how the underlying MT network is organized and how this transport takes place. We have identified a centriole-containing centrosome close to the oocyte nucleus. Remarkably, the centrosomal components, γ-tubulin and Drosophilapericentrin-like protein also strongly accumulate at the periphery of this nucleus. MT polymerization after cold-induced disassembly in wild type and in gurken mutants suggests that in the oocyte the centrosome-nucleus complex is an active center of MT polymerization. We further report that the MT network comprises two perpendicular MT subsets that undergo dynamic rearrangements during oogenesis. This MT reorganization parallels the successive steps in localization of gurken and oskar mRNAs. We propose that in addition to a highly polarized microtubule scaffold specified by the cortex oocyte, the repositioning of the nucleus and its tightly associated centrosome could control MT reorganization and, hence,oocyte polarization.
Guidance of trunk neural crest migration requires neuropilin 2/semaphorin 3F signaling
Authors: Gammill Laura S. , Gonzalez Constanza , Gu Chenghua , Bronner-Fraser Marianne
Published: December 2005

In vertebrate embryos, neural crest cells migrate only through the anterior half of each somite while avoiding the posterior half. We demonstrate that neural crest cells express the receptor neuropilin 2 (Npn2), while its repulsive ligand semaphorin 3F (Sema3f) is restricted to the posterior-half somite. In Npn2 and Sema3f mutant mice,neural crest cells lose their segmental migration pattern and instead migrate as a uniform sheet, although somite polarity itself remains unchanged. Furthermore, Npn2 is cell autonomously required for neural crest cells to avoid Sema3f in vitro. These data show that Npn2/Sema3f signaling guides neural crest migration through the somite. Interestingly, neural crest cells still condense into segmentally arranged dorsal root ganglia in Npn2nulls, suggesting that segmental neural crest migration and segmentation of the peripheral nervous system are separable processes.
Comparison of conventional testing to polymerase chain reaction in detection of Trichomonas vaginalis in indigenous women living in remote areas
Authors: Smith K S , Tabrizi S N , Fethers K A , Knox J B , Pearce C , Garland S M
Published: December 2005

There are high rates of Trichomonas vaginalis in remote areas of Central Australia. Conventional tests for T. vaginalis have low sensitivity in this setting. Aims of the study were to estimate the prevalence of T. vaginalis, to assess the presence of clinical signs and symptoms, to compare a T. vaginalis polymerase chain reaction (PCR) test with conventional methods of diagnosis, and to compare the PCR from different samples, including self-collected swabs (SCS). Of 205 women recruited, the prevalence of T. vaginalis was 24%. The prevalence of T. vaginalis was higher in women under 25 years (33%), compared with those who were 25–34 years (26%) and those over 35 years (15%, P < 0.05). The sensitivity of T. vaginalis PCR detection from SCS (94%) was not statistically different from a practitioner-collected HVS (96%), but was superior to urine PCR (74%) and conventional methods. After multivariate analysis, those women with high pH were almost three times more likely to be positive for T. vaginalis (odds ratio = 2.71 with 95% confidence interval 1.06–6.93, P = 0.037). Superior assays such as PCR should be a diagnostic option to adequately screen and treat women with T. vaginalis, in order to reduce complications, including the increased risk of HIV transmission.
Regression of invasive conjunctival squamous carcinoma in an HIV-positive patient on antiretroviral therapy
Authors: Holkar S , Mudhar H S , Jain A , Gupta M , Rogstad K E , Parsons M A , Singh A D , Rennie I G
Published: December 2005

Case history of an African woman presenting with advanced HIV and a painful conjunctival lesion is presented. A conjunctival biopsy revealed invasive squamous cell carcinoma, with orbital invasion on computed tomography scan. She was commenced on antiretroviral therapy. She refused surgery to remove the eye and orbital contents (exenteration), and was referred to palliative care. Gradually, her immune status and ocular symptoms improved. At ophthalmic review, the tumour had apparently completely regressed. This unprecedented phenomenon may be due to antiretroviral therapy. Discussion covers conjunctival carcinoma and behaviour of HIV-related tumours with antiretroviral therapy. Antiretroviral drugs may offer a better alternative to disfiguring surgery in the future.
Cervical dyskaryosis among women with and without HIV: prevalence and risk factors
Authors: Mbizvo E M , Msuya S E , Stray-Pedersen B , Chirenje M Z , Hussain A
Published: December 2005

Women in developing countries often present for medical care with advanced cervical cancer, although this condition is preventable through regular screening and early treatment. This study sought to identify the prevalence and risk factors for cervical dyskaryosis among women in Zimbabwe with and without HIV.

In a cross-sectional study, 200 consenting women were screened for cervical dyskaryosis and sexually transmitted infections (STI). The relationship between various risk factors for cervical dyskaryosis was examined. The overall prevalence of cervical dyskaryosis was high (19%), and significantly higher among HIV-infected women at 30% compared with 13% among seronegative women, with a peak at a younger age among seropositive women. Use of intravaginal herbs, practising intravaginal cleansing, being single, a history of three or more lifetime sexual partners and a history of previous STI were associated with cervical dysplasia.

The high frequency of cervical abnormality lends weight to the demand for implementation of regular screening programmes and health education.
Is triage an appropriate way of dealing with walk-in patients attending genitourinary medicine clinics?
Authors: Griffiths V , Ahmed-Jushuf I H
Published: December 2005

Genitourinary medicine services have come under severe workload pressure to deal with unprecedented demand over the past five years. Waiting times for patients wishing to access the service have increased significantly. In order to maintain open access for those who require acute attention, many services have introduced triage systems for patients who attend without appointments (walk-ins). We have evaluated a policy of triage for such patients, and the incidence of sentinel sexually transmitted infections (STIs) (gonorrhoea and chlamydia) was determined in those who failed to meet the criteria. Our study has shown a low incidence of STI (1.7%) in those who failed to meet the triage criteria, thus validating the policy.
Comprehensive clinical care on-site in men-only saunas: confidential STI/HIV screening outreach clinic
Authors: Lister Nichole A , Smith Anthony , Tabrizi Sepehr N , Garland Suzanne , Hayes Peter , Fairley Christopher K
Published: December 2005

During 2001 and 2002 an anonymous outreach-screening programme in Melbourne, Australia, offered testing for gonorrhoea and chlamydia on-site at men-only saunas. Modifications were made to this screening programme to offer a comprehensive testing clinic for sexually transmissible infections (STIs), including HIV. The comprehensive clinic was evaluated after one year of operation, and comparisons were made with the earlier anonymous screening programme. The comprehensive outreach clinic made contact with fewer men ( n = 557), however, men tested had a higher prevalence of gonorrhoea and chlamydia (17%), and all men tested positive for STIs/HIV were followed up. The findings and comparisons outlined in this paper may be used for different communities to decide what screening programme model best suits their individual situation: anonymous programme with fewer tests offered, confidential and comprehensive STI/HIV testing programme, or both. On the basis of our evaluation, we have opted to continue the comprehensive STI/HIV testing programme in local men-only saunas.
Audit on routine HIV testing in patients attending genitourinary medicine clinics
Authors: Lee V , Tobin J M
Published: December 2005

The Sexual Health Strategy was published in 2001. One of the recommendations was that all patients attending genitourinary (GU) medicine clinics for a sexual health screen should be offered an HIV test. This audit was undertaken in the GU medicine clinic at Portsmouth, offering a routine HIV antibody test to patients attending the clinic. This audit shows that patients will accept HIV testing when offered, during a routine GU medicine clinic visit. This initiative is important especially in areas with high HIV prevalence to identify undiagnosed HIV infections. Early diagnosis and intervention are important to reduce the morbidity and mortality of HIV infection.
Neurosyphilis in a young adult: very early tertiary syphilis?
Authors: Sabbatani Sergio , Manfredi Roberto , Chiodo Francesco
Published: December 2005

A rare episode of early neurosyphilis occurred in a 34-year-old, otherwise healthy, woman. Based on an isolated positive Borrelia burgdorferi serology (later interpreted as a cross-reaction), early ceftriaxone was initiated, in the suspect of Lyme borreliosis. Even after the diagnosis was corrected into that of a neurosyphilis, ceftriaxone administration was continued, until it achieved complete clinical and microbiological success after 24 days of treatment in a day-hospital setting, and three-weekly penicillin administrations. When considering the differential diagnosis, a luetic aetiology should not be underestimated when facing young patients with signs-symptoms of a meningoencephalitis. Our case report was characterized by an extremely low patient's age, compared with the occurrence of tertiary neurosyphilis, more than three years after the last sexual contacts. The diagnosis was confirmed by highly positive treponemal and non-treponemal serum and cerebrospinal fluid serology, and several suggestive clinical manifestations: seizures, altered mentation, cognitive impairment, lip drop, and anisochoria. These concomitant findings, together with a neuroradiological report indicating a diffuse meningoencephalitis, allowed us to confirm the diagnosis of neurosyphilis, together with a demonstrated cross-reaction of B. burgdorferi serology. Although ceftriaxone benefits from its once-daily administration (and can be easily delivered on outpatient basis), it is not the firstline treatment of neurosyphilis. However, our experience demonstrated a favourable and rapid response to ceftriaxone, in the absence of toxicity and disease sequelae.
The Phosphine Depression in Flame Atomic Spectrometry
Authors: Long Gary L. , Newman William J. , Klunder Greg L. , Mahaney Jim
Published: December 2005

The presence of PH3 in C2H2 can cause serious depressions of analyte atomic signals in air/C2H2 and N2O/C2H2 flames. In elements other than those in group 1a and 1b, a refractory metal-phosphorus-oxygen compound is formed during analyte desolvation and appears to slow the vaporization process. Data is presented describing the magnitude of the PH3 depression for elements routinely determined in these flames. The effects of the PH3 depression for these elements are compared to H3PO4 depressions, and the success of using chelating agents (EDTA) to reduce the depression is explored. Deviations from mathematical models describing the PH3 effect are discussed, and the possibility of incomplete PH, combustion occurring in the flames is explored.
A Study of the Amide III Band by FT-IR Spectrometry of the Secondary Structure of Albumin, Myoglobin, and γ-Globulin
Authors: Kaiden Koichi , Matsui Tomoko , Tanaka Shigeyuki
Published: December 2005

FT-IR spectrometry was applied to the identification of the secondary structure species of a living protein. The spectra of native myoglobin and albumin were obtained with methods using either KBr pellet or film formed on a KBr window from an aqueous solution. Pellet preparation of myoglobin and albumin caused the structure to change from α-helix to β-structure. The conformational changes that arise from heat denaturation of myoglobin, albumin, and γ-globulin were observed by the changes in the amide I, II, and III bands. The bands of the 1300, 1260, and 1235 cm−1 regions were respectively assigned to α-helix, disordered, and β-sheet structures. These band positions were substantiated by the spectra of β-lactoglobulin and α-casein. α-Helix structure probably changes to β-structure in the presence of alkali halide, and changes to disordered structure with heat denaturation in phosphate buffer solution. The secondary structure of a protein is further identified by use of the information obtained from the amide I, II, and III bands; the amide III band is especially important. Furthermore, it may be possible to characterize the species of secondary structures of proteins adsorbed on material surfaces.
The Steady-State and Decay Characteristics of Primary Fluorescence from Live Bacteria
Authors: Dalterio R. A. , Nelson W. H. , Brut D. , Sperry J. F. , Tanguay J. F. , Suib S. L.
Published: December 2005

The intrinsic steady-state fluorescence and fluorescence decay of Staphylococcus epidermidis, Pseudomonas fluorescens, Enterobacter cloacae, Escherichia coli, and Bacillus subtilis have been observed. Excitation spectra were obtained while emission at 430, 455, 487 and 514 nm was being monitored. Emission spectra were obtained with the use of excitation wavelengths of 340, 365, 405, 430 and 460 nm. Fluorescence lifetimes were measured at 430, 487, and 514 nm while selective excitation was caused at 340, 405, and 430 nm. The complex nature of the excitation and emission spectra reflects the presence of a number of different fluorophores. Attempts have been made to describe portions of the bacterial fluorescence in terms of the measured fluorescence properties including lifetimes of molecular components known for their widespread occurrence in bacteria and their relatively high quantum yields. Candidate fluorophores which have been considered include the pteridines, the structurally related flavins, and the pyridine coenzymes. The observation that characteristic sets of lifetimes have been obtained for each organism suggests that measurements of fluorescence lifetimes may be helpful in the rapid characterization of bacteria. Results are especially definitive in cases such as Pseudomonas fluorescens, where one marker fluorophore, a pteridine, is produced in large amounts.
Some Practical Aspects of FT-IR/PBDS. Part II: Sample Handling Procedures
Authors: Low M. J. D. , Morterra C.
Published: December 2005

FT-IR photothermal beam deflection spectroscopy (PBDS) is truly nondestructive in that none of the sample preparation methods needed for the IR examination of solids are mandated. Such nondestructive examination is, however, inefficient—in that long scanning times are frequently needed—and is not really required with many samples. If it is permissible to subject the sample to a simple hand grinding, efficiency can be greatly improved. Sample preparation and handling are discussed, and the peculiarities of certain samples are described. Particular emphasis is placed on the necessity of proper sample handling for surface studies, data of the vacuum pyrolysis of polyvinyledene being used as example.
Infrared Library Search on Principal-Component-Analyzed Fourier-Transformed Absorption Spectra
Authors: Wang Ching Po , Isenhour Thomas L.
Published: December 2005

Fourier-transformed infrared absorption spectra are compressed by principal-component analysis. Searches using the compressed data demonstrate the success of the compression. A search technique utilizing principal components in a prefilter selection produces the most efficient infrared library search method.
Spectra Structure Correlations for Phosphorous Trihalides, Thiophosphoryl Halides, and Phosphoryl Halides
Authors: Nyquist Richard A.
Published: December 2005

Spectra structure correlations are developed for phosphorous trihalides, thiophosphoryl halides, and phosphoryl halides that aid in the spectra-structure identification of organophosphorous compounds.
Frequency Interpolation of Discrete, Apodized, Magnitude Lineshapes
Authors: Serreqi Alessio , Comisarow Melvin B.
Published: December 2005

All Fourier spectrometers have a residual error in frequency measurement arising from the discrete nature of the experimental Fourier spectrum. This residual error is a systematic error which has a maximum value of half the channel spacing in the discrete spectrum. This systematic error can be reduced by interpolation of values on the discrete lineshape. The residual error remaining after interpolation has not yet been determined for apodized Fourier spectra. In this work, a systematic study of frequency interpolation of discrete, apodized, magnitude-mode lineshapes is reported. Absolute maximum frequency errors as a percentage of the discrete channel spacing are reported in graphical and tabular form as a function of the type of apodization window, the type of function used for three-point frequency interpolation, the number of zero-fillings, and ( T/ r), the ratio of the acquisition time to the relaxation time of the time domain signal. The results allow independent choice of the window function most appropriate for the dynamic range of the spectrum and the interpolating function/zero-filling level which optimizes the accuracy of frequency measurement. General observations are (1) that the interpolation error is reduced by an order of magnitude for each additional level of zero-filling and (2) that the interpolation error is essentially independent of T/r. For the Hanning window, the Hamming window, the three-term Blackman-Harris window, and the Kaiser-Bessel window, the parabola is the interpolating function of choice.
Are amniotic fluid C-reactive protein and glucose levels, and white blood cell counts at the time of genetic amniocentesis related with preterm delivery?
Authors: Tarım Ebru , Bağış Tayfun , Kılıçdağ Esra Bulgan , Sezgin Nurzen , Yanık Filiz
Published: December 2005

Objective: To compare women with spontaneous preterm delivery before 37 weeks and women who delivered at term with respect to amniotic fluid C-reactive protein (CRP), glucose levels, and white blood cell counts at the time of genetic amniocentesis.

Study design: The study was conducted on 216 pregnant women who underwent genetic amniocentesis between the 15th and 18th weeks of gestation at Baskent University Obstetrics and Gynecology Department. All patients were followed until delivery for the occurrence of pregnancy complication. Indications for amniocentesis included abnormal triple test results showing increased risk for Down's syndrome, advanced maternal age and sonographic findings indicative for chromosomal abnormalities. The samples were carried immediately to the laboratory for cytogenetic and biochemical examination. Women with spontaneous preterm delivery before 37 weeks (n=20) and those who delivered at term (n=196) were compared with respect to some maternal and infant characteristics, amniotic fluid C-reactive protein, glucose levels, and amniotic fluid white blood cell counts.

Results: During the study period 244 patients underwent amniocentesis. A chromosomal abnormality was present in 11 patients. 1 patient had a spontaneous pregnancy loss within 3 weeks after the procedure and 16 patients were delivered for fetal or maternal indications (preeclampsia, fetal growth restriction, placenta previa). The remaining 216 women were included in the study and investigated for the risk of preterm delivery. The prevalence of spontaneous preterm delivery before 37 weeks was 9.3% (20/216). There were no significant differences between the preterm delivery and the term delivery groups with respect to C-reactive protein levels and white blood cell counts. Mean amniotic glucose levels were significantly lower in the preterm delivery group (P<0.05). Amniotic fluid glucose levels of ≤46 mg/dL had a sensitivity of 100% and NPV of 100%.

Conclusion: Amniotic fluid glucose levels at the time of genetic amniocentesis are lower in women with spontaneous preterm delivery before 37 weeks compared to those who delivered at term. Amniotic fluid glucose levels of ≤46 mg/dL at the time of genetic amniocentesis may be more sensitive, cheaper and have higher negative predictive value than C-reactive protein levels and white blood cell counts for the prediction of patients in spontaneous preterm labor. The greatest benefit of amniotic fluid glucose testing might be when the physician judges the patient to be at low risk for preterm delivery.
Acromegaly in a multiple endocrine neoplasia type 1 (MEN1) family with low penetrance of the disease
Authors: Dreijerink Koen M A , van Beek André P , Lentjes Eef G W M , Post Jan G , van der Luijt Rob B , Dijk Marijke R Canninga-van , Lips Cornelis J M
Published: December 2005

Multiple endocrine neoplasia type 1 (MEN1) is an inherited syndrome that is characterised by the occurrence of tumours in the parathyroid glands, the endocrine pancreas, the pituitary gland and the adrenal glands and by neuroendocrine carcinoid tumours, often at a young age. The penetrance of MEN1 among gene carriers is reported to be high; 82–99% at age 50. We present a patient with a history of parathyroid adenomas also showing signs of acromegaly. He turned out to be a carrier of a MEN1 germ-line mutation in intron 3 (IVS3-6C > G). This germ-line mutation was also found in nine of his family members. However, none of these relatives have developed any MEN1-related lesion yet, although several are older than 60 years. To our knowledge, a MEN1 family with as few clinical features as this family has not been reported to date. Because MEN1 patients have an increased risk of developing acromegaly, insulin-like growth factor (IGF-I) levels are monitored periodically. We investigated whether IGF-I levels might serve as a presymptomatic marker for acromegaly; 9% (3/33) of MEN1 patients showed temporary IGF-I elevations. One patient (1/3) later developed clinical signs of acromegaly. Possibly, acromegaly in MEN1 is preceded by a transient preacromegalic state.
Characterization of the humoral immune response to glutamic acid decarboxylase in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) and/or type 1 diabetes
Authors: Ronkainen Matti S , Härkönen Taina , Perheentupa Jaakko , Knip Mikael
Published: December 2005

Objective: A humoral autoimmune response to glutamic acid decarboxylase (GAD65) is common both in patients with type 1 diabetes and in those with the autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome, while overt type 1 diabetes is relatively rarely diagnosed in APECED patients. The aim of this study was to assess whether this difference in the incidence of type 1 diabetes is associated with variability in the humoral immune response to GAD65, one of the major autoantigens in type 1 diabetes.

Methods: Epitope- and isotype-specific GAD65 autoantibodies were analysed in 20 patients with APECED and 20 patients with newly diagnosed type 1 diabetes alone by radiobinding assays.

Results: GAD65 autoantibodies targeted the middle and carboxy-terminal regions of GAD65 and occasionally the amino-terminal region in the APECED patients and comprised mainly the IgG1 subclass and less frequently the IgG2 and IgG4 subclasses. The profile of epitope- and isotype-specific GAD65 autoantibodies was similar in type 1 diabetes and APECED, except that IgG2 subclass antibodies were observed more often and at higher levels in the patients with type 1 diabetes alone (P < 0.05). None of the measured parameters separated APECED patients with type 1 diabetes from those without type 1 diabetes.

Conclusion: APECED-associated humoral autoimmunity to GAD65 does not differ markedly from that observed in type 1 diabetes; only IgG2-GAD65 antibodies may be more closely associated with the latter entity.
Functional analysis of the I.3, I.6, pII and I.4 promoters of CYP19 (aromatase) gene in human osteoblasts and their role in vitamin D and dexamethasone stimulation
Authors: Enjuanes Anna , Garcia-Giralt Natalia , Supervía August , Nogués Xavier , Ruiz-Gaspà Silvia , Bustamante Mariona , Mellibovsky Leonardo , Grinberg Daniel , Balcells Susana , Díez-Pérez Adolfo
Published: December 2005

Objective: Current evidence suggests that extragonadal estrogens play an important role in bone metabolism. Estrogen biosynthesis is catalyzed by P450aromatase, encoded by the CYP19 gene. The aims of this paper were to study CYP19 gene expression in human osteoblasts under several hormone and cytokine treatments and to define promoter regions involved in this regulation.

Methods: CYP19 transcript levels were measured from primary human osteoblasts and MG-63 cells by real-time PCR in basal conditions, and in response to seven different hormones and cytokines. Four promoters of CYP19 gene were cloned upstream of the luciferase gene and transfected into MG-63 cells. The effect of vitamin D and dexamethasone in these promoter activities was evaluated.

Results: Vitamin D and dexamethasone were potent stimulators of CYP19 transcription, while testosterone and 17β-estradiol stimulated moderately. Promoter pII proved the most potent in driving transient luciferase expression. Promoter I.4 displayed moderate activity, while promoters I.3 and I.6 were weak. A region upstream of exon I.3, including exon I.6, was identified as containing repressor elements of promoter pII. Promoter I.3 activity was modulated by repressors located within exon I.3, while an enhancer of promoter I.4 was detected within exon I.4. In the absence of fetal calf serum, dexamethasone stimulation was observed on promoters I.3 and I.4, while vitamin D stimulation acted only on promoter I.3.

Conclusions: Four regulatory regions of promoters pII, I.3 and I.4 are relevant to CYP19 expression in human osteoblasts. Vitamin D and dexamethasone modulate transcription through these regions.
Sex-specific association of PTPN22 1858T with type 1 diabetes but not with Hashimoto’s thyroiditis or Addison’s disease in the German population
Authors: Kahles Heinrich , Ramos-Lopez Elizabeth , Lange Britta , Zwermann Oliver , Reincke Martin , Badenhoop Klaus
Published: December 2005

Background: Endocrine autoimmune disorders share genetic susceptibility loci, causing a disordered T-cell activation and homeostasis (HLA class II genes, CTLA-4). Recent studies showed a genetic variation within the PTPN22 gene to be an additional risk factor.

Materials and Methods: Patients with type 1 diabetes (n = 220), Hashimoto’s thyroiditis (n = 94), Addison’s disease (n = 121) and healthy controls (n = 239) were genotyped for the gene polymorphism PTPN22 1858 C/T.

Results: Our study confirms a significant association between allelic variation of the PTPN22 1858 C/T polymorphism and type 1 diabetes mellitus (T1D). 1858T was observed more frequently in T1D patients (19.3% vs 11.3%, P = 0.0009; odds ratio for allele T = 1.88, 95% confidence interval [1.3–2.7]). Furthermore, we found a strong association in female patients with T1D (P = 0.0003), whereas there was no significant difference between male patients with type 1 diabetes and male controls. No significant difference was observed between the distribution of PTPN22 C/T in patients with Hashimoto’s thyroiditis or Addison’s disease and healthy controls.

Conclusion: The PTPN22 polymorphism 1858 C/T may be involved in the pathogenesis of type 1 diabetes mellitus by a sex-specific mechanism that contributes to susceptibility in females.
GH responsiveness varies during the menstrual cycle
Authors: Gleeson Helena K , Shalet Stephen M
Published: December 2005

Objective: The GH–IGF-1 axis is affected by oestrogen. Both endogenous and exogenous oestrogen facilitates the central drive of pulsatile GH secretion. However, the effect on IGF-1 levels is more subtle, and a reduction in GH sensitivity has been proposed. The IGF generation test has confirmed reduced GH sensitivity with high doses of exogenous oestrogen. It is not known, however, whether fluctuant levels of endogenous oestrogen modify GH sensitivity. To investigate this further, women were challenged with the IGF-1 generation test at different stages of the menstrual cycle.

Methods: Nine women (age 38(6) years (mean (s.d.)) with regular menstrual cycles were recruited. An IGF-1 generation test, s.c. injection of 7 mg GH, was performed in the early-follicular (EF), periovulatory (PO) and midluteal (ML) phases. IGF-1, insulin-like growth factor binding protein (IGFBP)-3 and acid-labile subunit (ALS) levels were measured at baseline and 24 h after GH administration.

Results: Oestradiol levels were lower in the EF than PO or ML phases (32.6(7.8) vs 69.6(16.2) vs 66.6(23.6) pg/ml respectively (repeated measures ANOVA, P < 0.001)). Baseline IGF-1 was lower, but increment IGF-1 (peak minus baseline) was higher in the EF than PO or ML phases (baseline: 291.8(56.6) vs 335.0(55.2) vs 346.6(78.2) ng/ml (P = 0.008); increment IGF-1: 234.6(59.2) vs 194.7(37.8) vs 185.2(37.3) ng/ml (P = 0.008)).

Conclusions: Increased endogenous oestrogen levels are associated with only a modestly elevated baseline IGF-1 from midcycle onward despite a previously reported twofold increase in GH secretion. In parallel with this apparent GH insensitivity, increased endogenous oestrogen levels are associated with reduction in GH sensitivity evidenced by reduction in increment IGF-1. This may have clinical implications for women with isolated GH deficiency with regular menstrual cycles on a fixed dose of GH. This possibility requires further study.
Lithium stimulates proliferation in cultured thyrocytes by activating Wnt/β-catenin signalling
Authors: Rao A S , Kremenevskaja N , Resch J , Brabant G
Published: December 2005

Background: Lithium, clinically used in the treatment of bipolar disorders, is well known to induce thyroid growth. However, the mechanism involved is only incompletely characterized. Although it is conventionally believed that thyroid proliferation depends on the thyroid-stimulating hormone (TSH)/cAMP/cAMP response element binding protein (CREB) pathway, recent data indicate that Wnt/β-catenin signalling may be of critical importance. In other cell types lithium activates canonical Wnt signalling by GSK-3β inhibition, which in turn stabilizes cytosolic free β-catenin. Here we investigated the potential modulation of Wnt/β-catenin signalling under lithium treatment in primary and neoplastic human thyrocytes.

Methods: Primary (S18) and neoplastic (NPA, FTC133) thyrocytes treated with and without LiCl were analysed using Western blotting, immunoprecipitation, reporter-gene assay, MTT proliferation assay and transfection studies.

Results: LiCl dose-dependently inhibited GSK-3β, stabilized free β-catenin and inhibited β-catenin degradation. Furthermore, LiCl altered the assembly of adherens junction by upregulating the E-cad-herin repressor, Snail, and downregulated E-cadherin expression. At a dose of 5 mM, LiCl significantly increased the proliferative potency of thyrocytes, which appeared to be mediated by β-catenin, since nuclear β-catenin stimulated T-cell factor/lymphoid enhancer factor (TCF/LEF)-mediated transcription and upregulated downstream targets like cyclin D1. To characterize the specificity of Wnt/β-catenin-driven thyrocyte proliferation, we transfected primary thyrocytes and FTC133 cells with dominant negative TCF4 to block Wnt-dependent pathways or with dominant negative CREB to inhibit the TSH/cAMP cascade. In cells transfected with dominant negative CREB lithium-stimulated proliferation was unchanged whereas blocking Wnt/β-catenin by dominant negative TCF4 reduced proliferation by approx. 50%.

Conclusion: Our data indicate that Wnt/β-catenin signalling is of major importance in the control of lithium-dependent thyrocyte proliferation.
Analysis of the interaction between human steroid 21-hydroxylase and various monoclonal antibodies using comparative structural modelling
Authors: Miguel Ricardo Núñez , Chen Shu , Nikfarjam Laleh , Kominami Shiro , Carpenter Byron , Dal Pra Chiara , Betterle Corrado , Zanchetta Renato , Nakamatsu Takashi , Powell Michael , Hewer Rachel , Blundell Tom L , Smith Bernard Rees , Furmaniak Jadwiga
Published: December 2005

Objective: To study the interaction between human steroid 21-hydroxylase (21-OH) and monoclonal antibodies (MAbs) to 21-OH directed to 3 different epitopes recognised by 21-OH autoantibodies characteristic of autoimmune Addison’s disease.

Design: Build comparative structural models of 21-OH, 21-OH MAbs and complexes of 21-OH–21-OH MAbs and study the effects of 21-OH MAbs on 21-OH enzyme activity. Then, analyse the relationship between sites important for binding of 21-OH MAbs and 21-OH autoantibodies and sites important for 21-OH enzyme activity.

Methods: Variable (V) regions of 21-OH MAbs (M21-OH1, M21-OH3, M21-OH5) were sequenced and models of the MAbs built using structures of antibodies in the database as templates. A comparative model of 21-OH was built using the crystal structure of rabbit cytochrome p450 2c5/3LVdH as template. 21-OH enzyme activity was measured in terms of conversion of [3H]progesterone to deoxycorticosterone and the effect of purified MAb IgGs on 21-OH enzyme activity was assessed.

Results: M21-OH1, M21-OH3 and control MAb had no effect on 21-OH enzyme activity with 88.8% ± 24% (n = 6), 86.7% ± 7.6% (n = 6) and 86.5% ± 10.6% (n = 6) of activity remaining in the presence of the respective IgGs. This was consistent with the epitopes for M21-OH1 and M21-OH3 being located distant from 21-OH enzyme active sites in our 21-OH model. The epitope for M21-OH5 which inhibited 21-OH enzyme activity (48.5 ± 8.3% activity remaining; P < 0.001 compared with control MAb IgG) was found close to the redox protein binding site in our 21-OH model.

Conclusions: A comparative model of 21-OH has been produced. Analysis of experimental data in the context of the model suggests that M21-OH5 inhibits 21-OH enzyme activity through interference with redox protein binding.
Plasma calcitonin gene-related peptide is increased prior to obesity, and sensory nerve desensitization by capsaicin improves oral glucose tolerance in obese Zucker rats
Authors: Gram Dorte X , Hansen Anker J , Wilken Michael , Elm Torben , Svendsen Ove , Carr Richard D , Ahrén Bo , Brand Christian L
Published: December 2005

Objective: It has earlier been demonstrated that capsaicin-induced desensitization improves insulin sensitivity in normal rats. However, whether increased capsaicin-sensitive nerve activity precedes the onset of insulin resistance in diet-induced obesity – and therefore might be involved in the pathophysiology – is not known. Further, it is of relevance to investigate whether capsaicin desensitization improves glycaemic control even in obese individuals and we therefore chose the obese Zucker rats to test this.

Design and methods: Plasma levels of calcitonin gene-related peptide (CGRP; a marker of sensory nerve activity) was assessed in 8-week-old Zucker rats. To investigate whether capsaicin desensitization (100 mg/kg at 9 weeks of age) would also ameliorate glycaemia in this non-diabetic model, we assessed oral glucose tolerance at 7 weeks after capsaicin.

Results: It was found that plasma CGRP levels were elevated in obese Zucker rats prior to the onset of obesity (16.1±3.4 pmol/l in pre-obese Zucker rats vs 6.9±1.1 pmol/l in lean littermates; P = 0.015) despite similar body weights. Furthermore, capsaicin desensitization reduced both fasting blood glucose (4.3±0.2 mmol/l vs 5.1±0.2 mmol/l in controls; P = 0.050) as well as the mean blood glucose level during an oral glucose tolerance test (OGTT) (6.8±0.3 mmol/l vs 8.6±0.5 mmol/l in control obese rats; P = 0.024) whereas the plasma insulin levels during the OGTT were unchanged. However this did not lead to an improvement in insulin resistance or to a reduction of tissue triglyceride accumulation in muscle or liver.

Conclusion: We concluded that capsaicin-induced sensory nerve desensitization improves glucose tolerance in Zucker rats. Since, in this study, plasma CGRP levels, a marker of sensory nerve activity, were increased in the pre-obese rats, our data support the hypothesis that increased activity of sensory nerves precedes the development of obesity and insulin resistance in Zucker rats.
Could cortisol explain the association between birth weight and cardiovascular disease in later life? A meta-analysis
Authors: van Montfoort N , Finken M J J , le Cessie S , Dekker F W , Wit J M
Published: December 2005

Objective: Studies about the association between birth weight and circulating cortisol level have been published from 1998 onwards. However, their findings were inconsistent. To quantitatively assess the overall association between birth weight and circulating cortisol level, we aimed to perform a meta-analysis of the published literature.

Methods: A literature search was conducted in PubMed, and selected papers were systematically reviewed. A pooled regression coefficient was calculated for the entire group as well as for males and females separately.

Results: Data from 11 study populations were pooled (n = 2301). These populations differed with respect to geographical area, age, sex distribution, inclusion criteria and gestational age. We found a statistically significant inverse association between birth weight and circulating cortisol level: a 1 kg lower birth weight was associated with a 25.3 nmol/l (95% confidence interval (CI): 5.9–44.8) higher cortisol level. Separate results were reported for males and females in six study populations. The association in males was 20.6 nmol/l per kg (95% CI: 4.2–37.0) and in females it was 30.9 nmol/l per kg (95% CI: 7.4–54.4).

Conclusion: Differences between study populations hampered the comparability of the included studies. Although the majority of studies were underpowered, by using a meta-analytic approach we found an inverse association between birth weight and circulating cortisol level. Thus, our findings suggest that there is some evidence for a possible role of the hypothalamus–pituitary–adrenal axis in the epidemiological association between birth weight and cardiovascular disease. However, the strength of the overall association between birth weight and circulating cortisol level was weak.
Cytoskeleton and cell cycle control during meiotic maturation of the mouse oocyte: integrating time and space
Authors: Brunet Stephane , Maro Bernard
Published: December 2005

During meiotic maturation of mammalian oocytes, two successive divisions occur without an intermediate phase of DNA replication, so that haploid gametes are produced. Moreover, these two divisions are asymmetric, to ensure that most of the maternal stores are retained within the oocyte. This leads to the formation of daughter cells with different sizes: the large oocyte and the small polar bodies. All these events are dependent upon the dynamic changes in the organization of the oocyte cytoskeleton (microtubules and microfilaments) and are highly regulated in time and space. We review here the current knowledge of the interplay between the cytoskeleton and the cell cycle machinery in mouse oocytes, with an emphasis on the two major activities that control meiotic maturation in vertebrates, MPF (Maturation promoting factor) and CSF (Cytostatic factor).
Expression of Polycomb-group genes in human ovarian follicles, oocytes and preimplantation embryos
Authors: Hinkins M , Huntriss J , Miller D , Picton H M
Published: December 2005

Mammalian oocytes possess unique properties with respect to their ability to regulate and reprogram chromatin structure and epigenetic information. Proteins containing the conserved chromodomain motif that is common to thePolycomb-group(Pc-G) proteins and the heterochromatin-associated protein HP1, play essential roles in these processes and more specifically, in X-chromosome inactivation in female zygotes and extra-embryonic tissues and in the regulation of genomic imprinting. To characterize the potential role of these proteins in the regulation of epigenetic events during early human development, we utilized a degenerate PCR priming assay to assess the expression of mRNAs of chromodomain proteins in cDNA samples derived from the human female germline and preimplantation embryos. Expression of mRNAs of HP1 genes was observed in ovarian follicles, (HP1HSα,HP1HSβ,HP1HSγ), mature oocytes (HP1HSα,HP1HSβ), cleavage stage preimplantation embryos (HP1HSα,HP1HSβ,HP1HSγ) and blastocysts (HP1HSα,HP1HSγ). Transcripts for threePc-Ggenes, which are essential for early mammalian development (Yin Yang 1(YY1),Enhancer of Zeste-2(EZH2) andEmbryonic Ectoderm Development(EED)) and that are essential for the regulation of X-inactivation and certain imprinted genes (EED) were revealed by gene-specific-PCR expression analysis of human ovarian follicles, oocytes and preimplantation embryos.YY1 andEZH2transcripts were additionally detected in metaphase II oocytes.
Carnitine/organic cation transporter OCTN2-mediated transport of carnitine in primary-cultured epididymal epithelial cells
Authors: Kobayashi Daisuke , Irokawa Masanori , Maeda Tomoji , Tsuji Akira , Tamai Ikumi
Published: December 2005

Carnitine is essential for the acquisition of motility and maturation of spermatozoa in the epididymis, and is accumulated in epididymal fluid. In this study, carnitine transport into primary-cultured rat epididymal epithelial cells was characterized to clarify the nature of the transporter molecules involved. Uptake of carnitine by primary-cultured epididymal epithelial cells was time, Na+and concentration dependent. Kinetic analysis of carnitine uptake by the cells revealed the involvement of high- and low-affinity transport systems withKm values of 21 μM and 2.2 mM respectively. The uptake of carnitine by the cells was significantly reduced by inhibitors of carnitine/organic cation transporter (OCTN2), such as carnitine analogues and cationic compounds. In RT-PCR analysis, OCTN2 expression was detected. These results demonstrated that the high-affinity carnitine transporter OCTN2, which is localized at the basolateral membrane of epididymal epithelial cells, mediates carnitine supply into those cells from the systemic circulation as the first step of permeation from blood to spermatozoa.
Stops and starts in mammalian oocytes: recent advances in understanding the regulation of meiotic arrest and oocyte maturation
Authors: Mehlmann Lisa M
Published: December 2005

Mammalian oocytes grow and undergo meiosis within ovarian follicles. Oocytes are arrested at the first meiotic prophase, held in meiotic arrest by the surrounding follicle cells until a surge of LH from the pituitary stimulates the immature oocyte to resume meiosis. Meiotic arrest depends on a high level of cAMP within the oocyte. This cAMP is generated by the oocyte, through the stimulation of the GsG-protein by the G-protein-coupled receptor, GPR3. Stimulation of meiotic maturation by LH occurs via its action on the surrounding somatic cells rather than on the oocyte itself. LH induces the expression of epidermal growth factor-like proteins in the mural granulosa cells that act on the cumulus cells to trigger oocyte maturation. The signaling pathway between the cumulus cells and the oocyte, however, remains unknown. This review focuses on recent studies highlighting the importance of the oocyte in producing cAMP to maintain arrest, and discusses possible targets at the level of the oocyte on which LH could act to stimulate meiotic resumption.
Mad2 is required for inhibiting securin and cyclin B degradation following spindle depolymerisation in meiosis I mouse oocytes
Authors: Homer Hayden A , McDougall Alex , Levasseur Mark , Murdoch Alison P , Herbert Mary
Published: December 2005

Mad2 is a pivotal component of the spindle assembly checkpoint (SAC) which inhibits anaphase promoting complex/cyclo-some (APC/C) activity by sequestering Cdc20 thereby regulating the destruction of securin and cyclin B. During mitosis, spindle depolymerisation induces a robust Mad2-dependent arrest due to inhibition of securin and cyclin B destruction. In contrast to mitosis, the molecular details underpinning the meiosis I arrest experienced by mouse oocytes exposed to spindle depolymerisation remain incompletely characterised. Notably, the role of Mad2 and the fate of the anaphase-marker, securin, are unexplored. As shown previously, we find that spindle depolymerisation by nocodazole inhibits first polar body extrusion (PBE) and stabilises cyclin B and cyclin-dependent kinase 1 activity in mouse oocytes. Here we show that stabilisation of cyclin B in nocodazole can be sustained for several hours and is associated with stabilisation of securin. These effects are SAC-mediated as, in oocytes depleted of the majority of Mad2 by morpholino antisense, securin and cyclin B are destabilised and 15% of oocytes undergo PBE. This reflects premature APC/C activation as a mutant form of cyclin B lacking its APC/C degradation signal is stable in Mad2-depleted oocytes. Moreover, homologues do not disjoin during the prolonged meiosis I arrest (> 18 h) induced by nocodaozole indicating that a non-cleavage mechanism is insufficient on its own for resolution of arm cohesion in mammalian oocytes. In conclusion, when all kinetochores lack attachment and tension, mouse oocytes mount a robust Mad2-dependent meiosis I arrest which inhibits the destruction of securin and cyclin B.
Keeping sister chromatids together: cohesins in meiosis
Authors: Revenkova E , Jessberger R
Published: December 2005

Meiosis poses unique challenges to chromosome dynamics. Before entry into meiosis, each chromosome is duplicated and gives rise to two sister chromatids linked to each other by cohesion. Production of haploid gametes requires segregation of homologous chromosomes in the first meiotic division and of sister chromatids in the second. To ensure precise distribution of chromosomes to the daughter cells, sister chromatid cohesion (SCC) has to be dissolved in two steps. Maintenance and regulation of SCC is performed by the cohesin protein complex. This short review will primarily focus on the core cohesin proteins before venturing into adjacent territories with an emphasis on interacting proteins and complexes. It will also concentrate on mammalian meiosis and only occasionally discuss cohesion in other organisms.