Role of Shigella infection in endometriosis: a novel hypothesis.

Endometriosis is the presence of endometrial cells and stroma at ectopic sites outside the uterine cavity. The natural history of endometriosis is uncertain, its etiology unknown, the clinical presentation inconsistent, diagnosis difficult and the treatment poorly standardized. It causes significant morbidity due to pelvic pain and infertility among 15-25% of women during their reproductive age. The benign disease causes peritoneal inflammation, fibrosis, adhesions and ovarian cysts but displays features of malignancy, like neo-vascularization, local invasion and distant metastasis. Mechanical, hormonal, immunological, environmental and genetic factors have been implicated in its etiology but provide inconclusive explanations. Present study was carried out on ectopic and eutopic endometriotic tissue specimens collected during laproscopy/laprotomy from cases of endometriosis. mRNA was isolated from the tissues and converted to cDNA by RT and subsequently subjected to differential display Polymerase Chain Reaction using seven sets of arbitrary primers. A unique band was identified only in the ectopic endometriotic tissue, which was sequenced. BLAST search results revealed sequence homology to shigella bacterial DNA leading us to hypothesize that infection may be playing a role in the etiology of endometriosis. This is the first report implicating the role of bacterial infection in the etiology of endometriosis. Shigella is known to invade the mucosa of the colon through the feco-oral route causing Shigellosis. The pathogenesis of shigellosis involves inflammation, ulceration, haemorrhage, tissue destruction and fibrosis of the colonic mucosa resulting in abdominal pain and diarrhoea/dysentery, this is similar to the pathogenesis of endometriosis which also involves inflammation, haemorrhage, tissue destruction and fibrotic adhesions of the pelvic peritoneum resulting in abdominal pain and infertility. The non-motile shigella bacteria invade the deeper mucosal layers by travelling from cell to cell of colonic epithelium, reaching the lamina propria of the colonic mucosa. We propose that, by the same mechanism, the bacteria travel across the colon wall to reach the outer peritoneal surface of the colon, which is in close proximity to the posterior uterine surface in the Pouch of Douglas, the site which incidentally happens to be the commonest site of early endometriosis. Our hypothesis therefore proposes that shigella or shigella-like organisms may be the trigger for the initiation of immunological changes in the pelvic peritoneum causing endometriosis. Once the endometrial cells are implanted at ectopic sites they are sustained by hormones and angiogenic factors. Hence "Infection hypothesis" provides a novel explanation for the etiopathogenesis of endometriosis.

Association of progesterone receptor gene polymorphism (PROGINS) with endometriosis, uterine fibroids and breast cancer.

Endometriosis, uterine fibroids and breast cancer are female health disorders associated with a great deal of morbidity. Since all these disorders are hormone responsive, our present study has been carried out to identify the association of 306bp Alu insertion polymorphism in intron 7 of progesterone receptor gene (PROGINS). DNA was isolated from the blood samples of 445 Asian Indian women, which included 100 endometriosis, 80 fibroids and 157 cases of breast cancer along with 108 age matched normal healthy women as controls. PROGINS polymorphism was assessed by PCR followed by agarose gel electrophoresis. Results showed that T2 allele frequency is 5%, 10% and 14.6% in endometriosis, uterine fibroids and breast cancer, as compared to 5.5% in controls. This indicates that PROGINS can be considered as a predisposing risk marker for breast cancer but not for endometriosis and uterine fibroids.

Optical spectroscopic and reverse-phase HPLC analyses of Hg(II) binding to phytochelatins.

Optical spectroscopy and reverse-phase HPLC were used to investigate the binding of Hg(II) to plant metal-binding peptides (phytochelatins) with the structure (gammaGlu-Cys)2Gly, (gammaGlu-Cys)3Gly and (gammaGlu-Cys)4Gly. Glutathione-mediated transfer of Hg(II) into phytochelatins and the transfer of the metal ion from one phytochelatin to another was also studied using reverse-phase HPLC. The saturation of Hg(II)-induced bands in the UV/visible and CD spectra of (gammaGlu-Cys)2Gly suggested the formation of a single Hg(II)-binding species of this peptide with a stoichiometry of one metal ion per peptide molecule. The separation of apo-(gammaGlu-Cys)2Gly from its Hg(II) derivative on a C18 reverse-phase column also indicated the same metal-binding stoichiometry. The UV/visible spectra of both (gammaGlu-Cys)3Gly and (gammaGlu-Cys)4Gly at pH 7.4 showed distinct shoulders in the ligand-to-metal charge-transfer region at 280-290 mm. Two distinct Hg(II)-binding species, occurring at metal-binding stoichiometries of around 1.25 and 2.0 Hg(II) ions per peptide molecule, were observed for (gammaGlu-Cys)3Gly. These species exhibited specific spectral features in the charge-transfer region and were separable by HPLC. Similarly, two main Hg(II)-binding species of (gammaGlu-Cys)4Gly were observed by UV/visible and CD spectroscopy at metal-binding stoichiometries of around 1.25 and 2.5 respectively. Only a single peak of Hg(II)-(gammaGlu-Cys)4Gly complexes was resolved under the conditions used for HPLC. The overall Hg(II)-binding stoichiometries of phytochelatins were similar at pH 2.0 and at pH 7.4, indicating that pH did not influence the final Hg(II)-binding capacity of these peptides. The reverse-phase HPLC assays indicated a rapid transfer of Hg(II) from glutathione to phytochelatins. These assays also demonstrated a facile transfer of the metal ion from shorter- to longer-chain phytochelatins. The strength of Hg(II) binding to glutathione and phytochelatins followed the order: gammaGlu-Cys-Gly<(gammaGlu-Cys)2Gly<(gammaGlu-Cy s)3Gly<(gamma Glu-Cys)4Gly.

Chain length-dependent Pb(II)-coordination in phytochelatins.

UV/visible and circular dichroism (CD) spectroscopy have been used to study the binding of Pb(II) to plant metal-sequestering peptides, phytochelatins (PCs), with the structure (gamma Glu-Cys)2Gly, (gamma Glu-Cys)3Gly and (gamma Glu-Cys)4Gly. Saturation of the Pb(II)-induced charge-transfer bands indicated that both (gamma Glu-Cys)2Gly and (gamma Glu-Cys)3Gly bound one metal ion per peptide molecule. However, (gamma Glu-Cys)4Gly formed two distinct species with stoichiometries of one and two Pb(II) ions per peptide molecule, respectively. The optical spectra of Pb(II)1-(gamma Glu-Cys)4Gly were similar to those of Pb(II)1-(gamma Glu-Cys)3Gly, whereas the spectra of Pb(II)2-(gamma Glu-Cys)4Gly were similar to those of Pb(II)1-(gamma Glu-Cys)2Gly. Since cysteinyl thiolates are the likely ligands for Pb(II) in PCs, Pb(II) appears to form two-, three- and four-coordinate complexes with PCs depending on their chain length. Furthermore, Pb(II) may exhibit multiple coordination in longer chain PCs as indicated by the formation of two Pb(II)-binding species of (gamma Glu-Cys)4Gly. The transfer of Pb(II) from glutathione to PCs and from shorter chain to longer chain PCs is also demonstrated.

Comparison between orientational and conformational orders in fluid lipid bilayers.

The orientational order as determined by 2H NMR and the infrared frequencies of the C--H stretching modes of the methylene groups have been measured for several systems (POPC, POPC/cholesterol and POPE), all in the fluid phase, and then were compared; this work reveals an unexpected linear correlation between them. This experimental result shows that both measurements are essentially sensitive to a common motion, most likely trans/gauche isomerisation. This new correlation with those already found in the literature suggest that several measurements related to the hydrophobic core of the fluid bilayer describe different aspects of a universal behavior. The correlation presented here does not extend to the lipid in gel phase where slower motions affect the NMR lineshape.