Identification of structural fingerprints for ABCG2 inhibition by using Monte Carlo optimization, Bayesian classification, and structural and physicochemical interpretation (SPCI) analysis.

The human breast cancer resistance protein (BCRP), one of the members of the large ATP binding cassette (ABC) transporter superfamily, is crucial for resistance against chemotherapeutic agents. Currently, it has been emerged as one of the best biological targets for the designing of small molecule drugs capable of eliminating multidrug resistance in breast cancer. In order to gain insights into the relationship between the molecular structure of compounds and the ABCG2 inhibition, a multi-QSAR approach using different methods was performed on a dataset of 294 ABCG2 inhibitors with diverse scaffolds. The best models obtained by different chemometric methods have the following statistical characteristics: Monte Carlo Optimization-based QSAR (sensitivity = 0.905, specificity = 0.6255, accuracy = 0.756, and MCC = 0.545), Bayesian classification model (sensitivity = 0.735, specificity = 0.775, and concordance = 0.757); structural and physicochemical interpretation analysis-random forest method (balance accuracy = 0.750, sensitivity = 0.810, and specificity = 0.700). Additionally, structural fingerprints modulating the ABCG2 inhibitory properties were identified from the best models of each method and also validated with each other. The current modelling study is an attempt to get a deep insight into the different important structural fingerprints modulating ABCG2 inhibition.

Insight into structural features of phenyltetrazole derivatives as ABCG2 inhibitors for the treatment of multidrug resistance in cancer.

ABCG2 is the principal ABC transporter involved in the multidrug resistance of breast cancer. Looking at the current demand in the development of ABCG2 inhibitors for the treatment of multidrug-resistant cancer, we have explored structural requirements of phenyltetrazole derivatives for ABCG2 inhibition by combining classical QSAR, Bayesian classification modelling and molecular docking studies. For classical QSAR, structural descriptors were calculated from the free software tool PaDEL-descriptor. Stepwise multiple linear regression (SMLR) was used for model generation. A statistically significant model was generated and validated with different parameters (For training set: r = 0.825; Q2 = 0.570 and for test set: r = 0.894, r2pred = 0.783). The predicted model was found to satisfy the Golbraikh and Trospha criteria for model acceptability. Bayesian classification modelling was also performed (ROC scores were 0.722 and 0.767 for the training and test sets, respectively). Finally, the binding interactions of phenyltetrazole type inhibitor with the ABCG2 receptor were mapped with the help of molecular docking study. The result of the docking analysis is aligned with the classical QSAR and Bayesian classification studies. The combined modelling study will guide the medicinal chemists to act faster in the drug discovery of ABCG2 inhibitors for the management of resistant breast cancer.

Identification of Chlamydiae and Mycoplasma species in ruminants with ocular infections.

Infectious keratoconjunctivitis (IKC) is a highly contagious ocular inflammatory condition, which is often reported in domestic small and large ruminants. Multiple infectious aetiologies are reported to be involved, but information about the role of certain fastidious bacterial pathogens such as chlamydiae and mycoplasmas is limited in India. Hence, this study was performed to determine the role of these pathogens and their identification by molecular approach. A total of 53 samples from 31 ovine, 14 caprine and eight bovine having clinical symptoms were collected and tested using species-specific PCR tests for chlamydiae and mycoplasmas followed by nucleotide sequence analysis. The results showed 77.41, 14.29 and 25% samples were chlamydiae positive in ovine, caprine and bovine, respectively, whereas 41.93, 14.29 and 37.5% prevalence of mycoplasma infection was detected in ovine, caprine and bovines, respectively. Chlamydophila abortus, Chlamydophila psittaci, Mycoplasma arginini and Mycoplasma hyorhinis were detected from tested samples. To the best of our knowledge, this is the first time these species are identified in IKC cases from India. Coinfection of both chlamydial and mycoplasmal species was detected in eight IKC cases of ovine which suggest synergistic roles played by both chlamydiae and mycoplasma in IKC samples.

Seroprevalence studies on animal chlamydiosis amongst ruminants in five states of India.

BACKGROUND AND AIM: Animal chlamydiosis, caused by different chlamydial species, is characterized by clinical or subclinical disease manifestations in cattle, buffalo, ovine, caprine and wild animal species. Animal chlamydiosis often remains underdiagnosed or undiagnosed, and its status in many parts of India is still unknown. Hence, the present study was conducted to determine the seroprevalence of animal chlamydiosis amongst ruminant livestock species of five states of India. MATERIALS AND METHODS: Totally, 2127 randomly selected serum samples collected from ruminant livestock species viz. cattle (n=430), buffaloes (n=429), sheep (906) and goats (n=362), were tested by agar gel precipitation test for chlamydiosis between 2002 and 2011. Precipitating antigen was prepared from locally isolated strain of Chlamydia psittaci after treatment with sodium deoxycholate. RESULTS: The chlamydial seroprevalence detected amongst ruminants in five states of India was: Himachal Pradesh: Cattle-10.90%, sheep-10.60% and goats- 22.46%; Punjab: Cattle-1.45%; Andhra Pradesh: Cattle-2.80%, buffaloes-0.93%, sheep-8.90% and goats-9.46%; Maharashtra: goats-8.33%; Jammu and Kashmir: sheep-12.50%. The mean seroprevalence values of each animal species are: Cattle-4.65%, buffaloes-0.93%, sheep-9.82% and goats-19.33%. CONCLUSION: The results indicate the endemic nature of animal chlamydiosis across five states in India. Hence, it requires further extensive studies in other parts of India also using chlamydial species-specific diagnostics to ascertain overall countrywide prevalence of the disease. The zoonotic nature of the chlamydiae of ruminant origin further adds significance to such prevalence studies.

Recurrent pneumomediastinum in a patient with rheumatoid arthritis.

Spontaneous pneumomediastinum (SPM); also known as mediastinal emphysema, is a rare and usually benign self-resolving appearance of extraluminal air in the mediastinum without any underlying trigger. This is an uncommon disorder mostly seen in the young males and classic clinical presentation is with chest pain, dyspnea, cough and appearance of subcutaneous emphysema. Although several connective tissue disorders have been reported in association with SPM, it is a rare occurrence in rheumatoid arthritis (RA) with only small number of cases reported in literature. We report a 69 years old male with RA who developed recurrent asymptomatic episodes of SPM detected over a period of one year. The recurrent but benign episodes of SPM in this patient reestablish the usual uncomplicated course of this unusual clinical entity even in the rare recurrent cases.

Abducens nerve palsy in a patient with scrub typhus: a case report.

Abducens nerve palsy is a known but rare complication of a few bacterial and viral infections like Mycoplasma pneumonia, cytomegalovirus, Epstein-Barr virus, Hanta virus, herpes zoster, and measles. Abducens nerve palsy due to scrub typhus is extremely rare and so far only one case has been reported in the literature. Scrub typhus is a febrile illness caused by rickettsia, Orientia tsutsugamushi, a gram negative intracellular obligate parasite which is endemic in Asia. This disease can present with wide range of clinical manifestations with involvement of any organ system, alone or in combination. Central nervous system involvement is very common and includes meningism, altered sensorium to focal neurological deficits. We present a rare manifestation of Scrub typhus in the form of sixth cranial nerve involvement which responded to the treatment with doxycycline.

Level of certain micro and macro minerals in blood of cattle from fluoride polluted localities of Udaipur, India.

Analysis of soil, fodder and water samples collected from some localities of Udaipur district, Rajasthan, India revealed high fluoride concentrations indicating the areas endemic for fluoride pollution. Concentration of micro and macro minerals was estimated in blood samples collected from cattle reared in these localities, and with clinical lesions suggestive of chronic fluoride toxicity. In comparison to healthy controls, zinc, copper and manganese levels were significantly (p < 0.05) lower, while cobalt and magnesium concentrations were significantly (p < 0.05) higher in fluoride-intoxicated cattle. Results of the present study suggested that interaction of fluoride with other minerals possibly played a role in pathogenesis of chronic fluoride intoxication.

Expression of estrogen receptor (ER) subtypes and ERbeta isoforms in colon cancer.

Colon cancer incidence and mortality rates are lower in females compared with males, and numerous epidemiological studies suggest that estrogen replacement therapy (ERT) reduces cancer risk in postmenopausal women. Two estrogen receptor (ER) subtypes, ERalpha and ERbeta, mediate genomic effects in target cells. The aim of this study was to determine the relative mRNA expression levels for ER subtypes and ERbeta isoforms in colon tumors, normal colonic mucosa, and colon cancer cell lines. ERalpha and ERbeta isoform mRNA levels were investigated in paired samples of colon tumors and normal mucosa from 26 patients using comparative reverse transcription-PCR and then Southern analyses. Constitutive steroid hormone receptor mRNA levels were determined for five colon adenocarcinoma cell lines using reverse transcription-PCR, and ERbeta levels were further studied in Caco-2 cells using Northern and Western analyses. ERbeta mRNA steady-state levels (relative to glyceraldehyde-3-phosphate dehydrogenase mRNA) were significantly decreased in colon tumors compared with normal mucosa in female patients. ERbeta1 and ERbeta2 isoform mRNA levels were significantly decreased in tumors from female patients, and ERbeta1 mRNA levels were also significantly lower in tumors from female patients compared with tumors from males. ERalpha mRNA levels were much lower than ERbeta levels and were similar between normal mucosa and tumor samples in both genders. ERbeta mRNA was detected in Caco-2, T84, and SW1116 cell lines and all lines were essentially negative for ERalpha mRNA. Caco-2 cells coexpressed ERbeta1, ERbeta2, and ERbeta5 mRNA, though a single protein transcript was observed. ERbeta protein was detected in normal colonic superficial epithelium, vascular smooth muscle and endothelium, and enteric neurons by immunohistochemistry. These data show that ERbeta is the predominant ER subtype in the human colon and that decreased levels of ERbeta1 and ERbeta2 mRNA are associated with colonic tumorigenesis in females. This information suggests that activation of ERbeta-mediated processes in the superficial colonic epithelium may have a role in the preventive effects observed for female gender and ERT usage.

Industrial fluorosis in cattle and buffalo around Udaipur, India.

Signs of dental discolouration, difficulty in mastication, bony lesions, lameness, debility and mortality in domesticated animals, reared around superphosphate fertiliser plants located approximately 15 km north of Udaipur, Rajasthan prompted us to investigate for the occurrence of fluorosis. Out of 166 animals clinically examined, the prevalence rate was 17.4% (4/23) in calves below 1 year of age, 37.2% (16/43) in cattle between 1 and 3 years, 61.3% (46/75) in cattle above 3 years and 72% (18/25) in buffalo above 1 year. Dental fluorosis was common in buffalo compared to cattle of all the age groups. Fluoride levels in fodder and water, consumed by the animals were much higher than the recommended permissible limit. Mean fluoride concentrations in serum and urine were 1.53 +/- 1.27 and 26.4 +/- 6.17 mg l(-1) in calves below 1 year of age, 0.56 +/- 0.17 and 26.2 +/- 3.86 mg l(-1) in cattle of 1-3 years, 0.49 +/- 1.13 and 27.5 +/- 4.63 mg l(-1) in cattle above 3 years and 0.60 +/- 0.07 and 28.6 +/- 4.73 mg l(-1) in buffalo over 1 year, respectively. The values were significantly (P < 0.01) higher than those of control animals kept over a 15-km distance from the factories. Fluoride concentrations in the environmental sample collected from the affected locality were 534.4 +/- 74.9 mg kg(-1) in fodder, 1.19 +/- 0.29 mg l(-1) in pond water and 0.479 +/- 0.351 mg l(-1) in tube well water. It was concluded that the consumption of fodder and water contaminated by the fumes and dusts emitting from superphosphate fertiliser plants resulted in the development of chronic fluorotic lesions in cattle and buffalo.

Hepatitis G virus infection in renal transplant recipients.

To determine the prevalence and clinical significance of hepatitis G virus (HGV)/GB virus C (GBV-C) infection in renal transplant recipients, prospectively collected serum samples from a cohort of cadaveric renal transplant patients were studied for the presence of HGV RNA using a sensitive reverse transcription 'nested'-polymerase chain reaction (RT-PCR) based on primers derived from the 5' untranslated region. All positive PCR amplicons were sequenced bidirectionally and aligned. The nucleotide substitution rate was estimated by the 6-parameter method, and a phylogenetic tree was constructed using the Neighbour-joining method. HGV RNA was detected in 11/93 (12%) patients pretransplant and in 15/90 (17%) patients 1-4 years post-transplant. All PCR amplicons were confirmed to be specific for HGV by sequencing. Phylogenetic tree construction revealed that 17 PCR amplicons had sequences related to HGV and one had a sequence related to GBV-C. Two HGV RNA-positive patients pretransplant became HGV RNA negative post-transplant, and seven HGV RNA-negative patients pretransplant became HGV RNA positive post-transplant. There was no relationship between hepatitis C virus (HCV) and HGV infection. There were also no differences in age, gender distribution, ethnic origin, the total number of blood units transfused and either graft or patient survival between patients who were positive or negative for HGV RNA. We conclude that HGV infection is common among renal transplant candidates and recipients. Most of the isolates had sequences related to the HGV prototype. HGV infection does not appear to adversely affect clinical outcome in renal transplant recipients during early follow-up.

Detection of GB virus-C/hepatitis G virus RNA in serum by reverse transcription polymerase chain reaction.

Three PCR methods based on the GB virus-C/hepatitis G virus (GBV-C/HGV) 5'UTR and NS3 genomic region were used for the detection of GBV-C/HGV RNA in serum of 62 patients with chronic hepatitis C virus (HCV) infection. Ten of 62 (16%) patients were found to have GBV-C/HGV RNA, which was confirmed by sequence analysis of the 5'UTR PCR amplicon. All methods appear to be specific, but methods based on the 5'UTR appear to be more sensitive.

Localization of platelet-derived growth factor beta receptor expression in the periepithelial stroma of human breast carcinoma.

Platelet-derived growth factor (PDGF) BB is secreted by most human breast carcinoma cells; however, only recently have PDGF beta receptors been demonstrated in malignant breast tissue. In the present study, the tissue localization of PDGF beta receptor expression was studied in human breast carcinoma and nonmalignant breast tissues stained using both immunofluorescence and immunoperoxidase techniques. We examined a total of 29 cases of breast carcinomas, which showed both in situ and invasive components. PDGF beta receptor staining was localized in the periepithelial stroma and was particularly intense in regions immediately adjacent to carcinoma in situ components in all tumors examined. A diffuse low level of PDGF beta receptor staining was seen throughout the stroma of eight nonmalignant breast tissues as well as of nonmalignant regions of tumor tissues. Image analysis was used to assess the coincidence of staining of PDGF beta receptor with epithelial or stromal cells in 13 of the 29 tumor tissues studied. Less than 5% of malignant ductal epithelium or myoepithelium showed PDGF beta receptor staining. Analysis with stromal cell type-specific markers indicated significant localization of PDGF beta receptor primarily within alpha smooth muscle actin-staining cells (32%) and vascular endothelial cells (41%) in the periepithelial stroma. PDGF beta receptor positivity was strongly associated with periepithelial stromal cells adjacent to the basement membrane surrounding regions of carcinoma in situ but was less intense in regions of invasive carcinoma where basement membrane was degraded. The absence of PDGF beta receptors on carcinoma cells and their presence in the surrounding stroma suggest a paracrine stimulation of adjacent stromal tissue by malignant epithelial cells in human breast tumors.

Fibronectin fibrils and growth factors stimulate anchorage-independent growth of a murine mammary carcinoma.

Stromal cells are important regulators of mammary carcinoma growth and metastasis. We have previously shown that a 3T3-L1 adipocyte cell line secretes hepatocyte growth factor (HGF), which stimulates proliferation of a murine mammary carcinoma (SP1) in monolayer cultures (DNA Cell Biol. 13, 1189-1897, 1994). We now examine the role of growth factors and the extracellular matrix protein fibronectin in stimulation of anchorage-independent growth of SP1 cells. Purified transforming growth factor-beta (TGF-beta) stimulated significant colony growth in soft agar cultures, whereas HGF had a lesser effect. Analysis by confocal microscopy revealed that carcinoma cell colonies contained extracellular microfibrils composed of fibronectin. Partial depletion of fibronectin from 7% FBS/agar cultures reduced the number of colonies; colony growth could be recovered by adding back exogenous fibronectin. Addition of the 70-kDa N-terminal fragment of fibronectin, which inhibits fibronectin fibril formation, reduced growth of SP1 cell colonies, but an 85-kDa fragment containing the cell binding domain did not inhibit colony growth. These findings indicate that deposition of extracellular fibronectin fibrils is necessary, but not sufficient, for anchorage-independent growth of SP1 mammary carcinoma cells; growth factors are also required. SP1 cells had less fibronectin mRNA and secreted less fibronectin protein under anchorage-independent conditions than under anchorage-dependent conditions, as determined by Northern blotting and immunoprecipitation analysis. Thus, both growth factors (HGF and TGF-beta) and fibronectin may be important regulators of paracrine stimulation by stromal cells of anchorage-independent growth of mammary carcinoma cells.

Antiestrogens: mechanisms and actions in target cells.

Antiestrogens, acting via the estrogen receptor (ER) evoke conformational changes in the ER and inhibit the effects of estrogens as well as exerting anti-growth factor activities. Although the binding of estrogens and antiestrogens is mutually competitive, studies with ER mutants indicate that some of the contact sites of estrogens and antiestrogens are likely different. Some mutations in the hormone-binding domain of the ER and deletions of C-terminal regions result in ligand discrimination mutants, i.e. receptors that are differentially altered in their ability to bind and/or mediate the actions of estrogens vs antiestrogens. Studies in a variety of cell lines and with different promoters indicate marked cell context- and promoter-dependence in the actions of antiestrogens and variant ERs. In several cell systems, estrogens and protein kinase activators such as cAMP synergize to enhance the transcriptional activity of the ER in a promoter-specific manner. In addition, cAMP changes the agonist/antagonist balance of tamoxifen-like antiestrogens, increasing their agonistic activity and reducing their efficacy in reversing estrogen actions. Estrogens, and antiestrogens to a lesser extent, as well as protein kinase activators and growth factors increase phosphorylation of the ER and/or proteins involved in the ER-specific response pathway. These changes in phosphorylation alter the biological effectiveness of the ER. Multiple interactions among different cellular signal transduction systems are involved in the regulation of cell proliferation and gene expression by estrogens and antiestrogens.

Hormone binding and transcription activation by estrogen receptors: analyses using mammalian and yeast systems.

We have used affinity labeling, site-directed mutagenesis and regional chemical mutagenesis in order to determine regions of the human estrogen receptor (ER) important in hormone binding, ligand discrimination between estrogens and antiestrogens, and transcriptional activation. Affinity labeling studies with the antiestrogen, tamoxifen aziridine and the estrogen, ketononestrol aziridine have identified cysteine 530 in the ER hormone binding domain as the primary site of labeling. In the absence of a cysteine at 530 (i.e. C530 mutant), C381 becomes the site of estrogen-compatible tamoxifen aziridine labeling. Hence these two residues, although far apart in the primary linear sequence of the ER protein, must be close in the three-dimensional structure of the protein, in the ER ligand binding pocket, so that the ligand can reach either site. Site-directed mutagenesis of selected residues in the ER and region-specific chemical mutagenesis of the ER hormone binding domain with initial phenotypic screening in yeast have enabled the identification of a region near C530 important in discrimination between estrogens and antiestrogens and of other residues important in hormone-dependent transcriptional activation. Some ER mutants with alterations in the carboxy-terminal portion of the hormone binding domain are transcriptionally inactive yet bind hormone and also function as potent dominant negative ERs, suppressing the activity of wild-type ER at low concentrations. These studies reveal a separation of the hormone binding and transcription activation functions of the ER. They are also beginning to provide a more detailed picture of the ER hormone binding domain and amino acids important in ligand binding and discrimination between different categories of agonist and antagonist ligands. Such information will be important in the design of maximally effective antiestrogens. In addition, since there is now substantial evidence for a mixture of wild-type and variant ERs in breast cancers, our studies should provide insight about the bioactivities of these variant receptors and their roles in modulating the activity of wild type ER, and should lead to a better understanding of the possible role of variant receptors in altered response or resistance to antiestrogen and endocrine therapy in breast cancer. In addition, some dominant negative receptors may prove useful in examining ER mechanisms of action and in suppressing the estrogen-dependent growth of breast cancer cells.

Electrocardiographic diagnosis of left ventricular hypertrophy in the presence of left bundle branch block: an echocardiographic correlation.

Surface electrocardiographic findings of 10 cases of left bundle branch block with echocardiographically determined left ventricular hypertrophy were compared with another 10 cases of left bundle branch block without left ventricular hypertrophy. Horizontal plane QRS- and T-wave angle > or = 150 degrees was highly sensitive (70%) and specific (90%) in diagnosing left ventricular hypertrophy in the presence of left bundle branch block. This diagnosis criterion was better than any other conventional criterion described before.