Nasal PCR assay for the detection of Mycobacterium leprae pra gene to study subclinical infection in a community.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae. Identification of Mycobacterium leprae is difficult in part due to the inability of the leprosy bacillus to grow in vitro. A number of diagnostic methods for leprosy diagnosis have been proposed. Both serological tests and molecular probes have shown certain potential for detection and identification of Mycobacterium leprae in patients. In this study, we have investigated whether Mycobacterium leprae DNA from the nasal secretion of healthy household contacts and the non contacts could be detected through PCR amplification as a method to study the sub clinical infection in a community. A total of 200 samples, 100 each from contacts and non contacts representing all age groups and sex were included in this study. The M. leprae specific primer (proline-rich region) of pra gene was selected and PCR was performed using extracted DNA from the sample. A total of 13 samples were found to be positive for nasal PCR for pra gene among the male and female contacts out of which 7% were males and 6% were females. Even though several diagnostic tools are available to detect the cases of leprosy, they lack the specificity and sensitivity. PCR technology has demonstrated the improved diagnostic accuracy for epidemiological studies and requires minimal time. Although nasal PCR studies have been reported from many countries it is not usually recommended due to the high percentage of negative results in the contact.

Biphasic dose-dependent effect of lithium chloride on survival of human hormone-dependent breast cancer cells (MCF-7).

Lithium, the first element of Group I in the periodic system, is used to treat bipolar psychiatric disorders. Lithium chloride (LiCl) is a selective inhibitor of glycogen synthase kinase-3ß (GSK-3ß), a serine/threonine kinase that regulates many cellular processes, in addition to its role in the regulation of glycogen synthase. GSK-3ß is emerged as a promising drug target for various neurological diseases, type-2 diabetes, cancer, and inflammation. Several works have demonstrated that lithium can either inhibit or stimulate growth of normal and cancer cells. Hence, the present study is focused to analyze the underlying mechanisms that dictate the biphasic oncogenic properties of LiCl. In the current study, we have investigated the dose-dependent effects of LiCl on human breast cancer cells (MCF-7) by assessing the consequences on cytotoxicity and protein expressions of signaling molecules crucial for the maintenance of cell survival. The results showed breast cancer cells respond in a diverse manner to LiCl, i.e., at lower concentrations (1, 5, and 10 mM), LiCl induces cell survival by inhibiting apoptosis through regulation of GSK-3ß, caspase-2, Bax, and cleaved caspase-7 and by activating anti-apoptotic proteins (Akt, ß-catenin, Bcl-2, and cyclin D1). In contrast, at high concentrations (50 and 100 mM), it induces apoptosis by reversing these effects. Moreover, LiCl also alters the sodium and potassium levels thereby altering the membrane potential of MCF-7 cells. Thus it is inferred that LiCl exerts a dose-dependent biphasic effect on breast cancer cells (MCF-7) by altering the apoptotic/anti-apoptotic balance.

In vitro mechanisms involved in the regulation of cell survival by lithium chloride and IGF-1 in human hormone-dependent breast cancer cells (MCF-7).

Lithium, the lightest of all solid elements, has been used for the treatment of bipolar disorder since 1970s and prescribed to millions of women worldwide. Lithium chloride (LiCl) has been considered to be a potent inhibitor of glycogen synthase kinase-3ß (GSK-3ß), a serine/threonine kinase that is involved in the control of cell proliferation, differentiation, and apoptosis. In addition, GSK-3ß has been found to be inhibited endogenously by insulin-like growth factor-1 (IGF-1), a potent mitogen that plays an important role in the survival, growth, and differentiation of normal and neoplastic cells. Although both IGF-1 and LiCl have the ability to inhibit GSK-3ß, the specific signaling difference that mediates the survival of breast cancer cells was not clear. Therefore, in the present study, MCF-7 cells (human breast cancer cells) were treated with or without IGF-1 or LiCl in the presence or absence of LY294002 or PD98059 (pharmacological inhibitors) for 24h. As the expression of signaling proteins is crucial in the maintenance of cell survival and apoptosis, we analyzed the cells using immunoblotting procedure. In summary, our results have shown that LiCl and IGF-1 mediates cell survival by inhibiting GSK-3ß but differ in their mechanisms. IGF-1 involves PI3K/Akt or MAPK pathways whereas LiCl is completely independent of these pathways. IGF-1 upregulates anti-apoptotic proteins whereas LiCl downregulates apoptotic proteins in order to maintain cell survival.