Dual oxidase-2 has an intrinsic Ca2+-dependent H2O2-generating activity

Duox2 (and probably Duox1) is a glycoflavoprotein involved in thyroid hormone biosynthesis, as the thyroid H2O2 generator functionally associated with Tpo (thyroperoxidase). So far, because of the impairment of maturation and of the targeting process, transfecting DUOX into nonthyroid cell lines has not led to the expression of a functional H2O2-generating system at the plasma membrane. For the first time, we investigated the H2O2-generating activity in the particulate fractions from DUOX2- and DUOX1-transfected HEK293 and Chinese hamster ovary cells. The particulate fractions of these cells stably or transiently transfected with human or porcine DUOX cDNA demonstrate a functional NADPH/Ca2+-dependent H2O2-generating activity. The immature Duox proteins had less activity than pig thyrocyte particulate fractions, and their activity depended on their primary structures. Human Duox2 seemed to be more active than human Duox1 but only half as active as its porcine counterpart. TPO co-transfection produced a slight increase in the enzymatic activity, whereas p22(phox), the 22-kDa subunit of the leukocyte NADPH oxidase, had no effect. In previous studies on the mechanism of H2O2 formation, it was shown that mature thyroid NADPH oxidase does not release O2*- but H2O2. Using a spin-trapping technique combined with electron paramagnetic resonance spectroscopy, we confirmed this result but also demonstrated that the partially glycosylated form of Duox2, located in the endoplasmic reticulum, generates superoxide in a calcium-dependent manner. These results suggest that post-translational modifications during the maturation process of Duox2 could be implicated in the mechanism of H2O2 formation by favoring intramolecular superoxide dismutation.

Antigenicity and immunogenicity of the C-terminal peptide of human thyroglobulin

Thyroglobulin (Tg) is cleaved into several peptides during thyroid hormone synthesis, an oxidative process. P40, an iodinated C-terminal peptide from human Tg, has a molecular weight of about 40 kDa and contains two hormonogenic sites. P40 is the smallest peptide that is still recognized by monoclonal antibodies from mice immunized with human Tg directed against its immunodominant region. Since P40 also contains several T-cell epitopes, it is a good candidate for studying the primary events involved in the process of hormone synthesis leading to thyroid autoimmunity. The present results show that P40 is recognized by Tg antibodies from patients with thyroid disorders and induces Tg antibodies in CBA mice. P40 may therefore be involved in the autoimmune process, thus providing a useful tool for diagnostic and therapeutic purposes.

Troubles sexuels chez 78 hémodialysés chroniques marocains de sexe masculin : étude clinique et endocrinienne

PURPOSE

To investigate the correlation between biochemical and endocrine variables with sexual disorders in 78 male patients on chronic hemodialysis at the Ibn Rochd University Hospital (Casablanca-Morocco).

METHODS

Seventy-eight male hemodialysis patients with chronic renal failure were evaluated with regard to their sexual function. All patients answered a personal questionnaire on their sexual activity. Hormone (FSH, LH, prolactin, testosterone, and parathyroid hormone) and zinc and ferritin assays were also performed.

RESULTS

The men reported erection (44.9%), libido (44.9%), ejaculation (26.8%), and orgasm (21.8%) disorders. Gynecomastia was observed in 17.9% of the patients. There was no correlation with weight nor the nature of the causal nephropathy nor with duration of dialysis. Levels of gonadotropins (FSH, LH), prolactin, and parathyroid hormone were elevated. Testosterone levels were low. Ferritinemia was elevated but there was no significant variation in zincemia. There was a negative curvilinear relationship between serum testosterone and sexual disorders, and between gynecomastia and ferritinemia. LH and prolactin levels were positively correlated with gynecomastia.

CONCLUSION

Abnormal hormonal and iron overload could be important factors involved in the complex pathogenesis of sexual dysfunction in chronic renal failure patients undergoning hemodialysis.

Immunostimulating activity of the hot water-soluble polysaccharide extracts of Anacyclus pyrethrum, Alpinia galanga and Citrullus colocynthis

Hot water polysaccharide extracts of Anacyclus pyrethrum (L.) Link. (family Compositae) Citrullus colocynthis (L.) Schrad. (family Cucurbitaceae) and Alpinia galanga (L.) Willd. (family Zingiberaceae) were tested for their immunostimulating activity in mice. The fractions from Anacyclus pyrethrum and Alpinia galanga showed a marked stimulating effect on the reticulo-endothelial system (RES) and increased the number of peritoneal exudate cells (PEC), and spleen cells of mice. In this case, the optimum doses were 50 and 25 mg/kg for the two fractions, respectively. On the other hand, the polysaccharide extracts of both Anacyclus pyrethrum and Alpinia galanga markedly enhanced the proliferation of the murine spleen cells in vitro using two tests (in vitro and in vivo effect). The results of the in vivo effect at a doses of 50 and 25 mg/kg, showed a stimulation index better than obtained with the in vitro effect at 50 and 25 microg/ml for Anacyclus pyrethrum and Alpinia galanga, respectively. While the extract of Citrullus colocynthis showed much weaker and variable immunostimulating activity.

Molecular detection of human papillomavirus in 594 uterine cervix samples from Moroccan women (147 biopsies and 447 swabs)

Uterine cervix cancer is the second most frequent female cancer after breast cancer in Morocco and represents a public health problem. Cervical cancer is highly linked to human papillomavirus (HPV) especially types 16 and 18 which are the highly oncogenic genotypes. To identify the contribution of HPV testing in the prevention of cervical cancer in Morocco, 147 biopsies collected at the Institut National d'Oncologie and 447 swabs from pathology laboratories and gynaecologist offices in Rabat were HPV analysed. HPV testing were made without any presumption of the histopathological diagnosis. A total of 147 paraffin-embedded biopsies and 447 exfoliated cervical samples were included. Based on histopathology results of the 147 biopsies, most cervical lesions were invasive carcinomas and non specific inflammations (NSI). With the molecular assay, HPV was detected in 91/147 (62%) patients. The high risk types 16 and 18 were found in 45% of the cases (41/91) and HPV 18 in 19% of the cases (17/91). Double infection with HPV 16 and 18 was found in 3 cases. Among the 447 swabs tested, 28 were HPV positives. Cytology results showed that 46% were inflammations (13/28). Among them, 10 patients had a NSI and only 3 patients had a cytology diagnosis of HPV infection. Based on these data, HPV testing should be associated to cervical cytology screening according to two algorithms established in function of the age of the patient and viral natural history. Combination of cytology and HPV testing allow identification of patient with high risk for development of high grade cervical lesions and improve cervical cancer prevention.

Human papillomavirus DNA in cervical lesions from Morocco and its implications for cancer control

To determine the types of human papillomaviruses (HPV) in northern Morocco, information which is needed for the design and use of HPV vaccines, we have analysed 129 cervical biopsies from this region. In our study, 91 cases were HPV positive, 45 cases had HPV-16 DNA, and 20 cases had HPV-18 DNA. This distribution of virus type was similar in inflammatory cervical lesions and in invasive cervical carcinomas. In conclusion, the HPV type distribution in Morocco is similar to that in other African Mediterranean countries, where the proportion of HPV-18 cases is significantly higher than in Europe. Determination of virus-type distribution is essential for vaccination programs.

Evaluation in the baboon model of (99m)Tc-biguanide as a tracer for renal imaging

Studies in various animal species have recently shown that (99m)Tc-BIG has practical and dosimetric benefits for renal imaging that could probably make it a good alternative to (99m)Tc-2, 3-dimercaptosuccinic acid ((99m)Tc-DMSA). In this study, using the baboon experimental model, the biodistribution of (99m)Tc-BIG and (99m)Tc-DMSA are compared. It is demonstrated that early good contrast imaging and more favourable dosimetry is possible with (99m)Tc-BIG compared to (99m)Tc-DMSA, confirming the quoted previous findings with small animals. Time-activity curves for kidneys and other organs support these findings, and MIRDOSE software provided the dosimetry.