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Biomedical subjects

L Mishra

Publications and source records attributed to L Mishra.

At least 19 recordsLinked to original sources
PubMed2006

Critical interactions between TGF-beta signaling/ELF, and E-cadherin/beta-catenin mediated tumor suppression.

Inactivation of the transforming growth factor-beta (TGF-beta) pathway occurs often in malignancies of the gastrointestinal (GI) system. However, only a fraction of sporadic GI tumors exhibit inactivating mutations in early stages of cancer formation, suggesting that other mechanisms play a critical role in the inactivation of this pathway. Here, we show a wide range of GI tumors, including those of the stomach, liver and colon in elf+/- and elf+/- / Smad4+/- mutant mice. We found that embryonic liver fodrin (ELF), a beta-Spectrin originally identified in endodermal stem/progenitor cells committed to foregut lineage, possesses potent antioncogenic activity and is frequently inactivated in GI cancers. Specifically, E-cadherin accumulation at cell-cell contacts and E-cadherin-beta-catenin-dependent epithelial cell-cell adhesion is disrupted in elf+/- / Smad4+/- mutant gastric epithelial cells, and could be rescued by ectopic expression of full-length elf, but not Smad3 or Smad4. Subcellular fractionation revealed that E-cadherin is expressed mainly at the cell membrane after TGF-beta stimulation. In contrast, elf+/- / Smad4+/- mutant tissues showed abnormal distribution of E-cadherin that could be rescued by overexpression of ELF but not Smad3 or Smad4. Our results identify a group of common lethal malignancies in which inactivation of TGF-beta signaling, which is essential for tumor suppression, is disrupted by inactivation of the ELF adaptor protein.

Animals↗
PubMed2006

RING finger-dependent ubiquitination by PRAJA is dependent on TGF-beta and potentially defines the functional status of the tumor suppressor ELF.

In gastrointestinal cells, biological signals for transforming growth factor-beta (TGF-beta) are transduced through transmembrane serine/threonine kinase receptors that signal to Smad proteins. Smad4, a tumor suppressor, is often mutated in human gastrointestinal cancers. The mechanism of Smad4 inactivation, however, remains uncertain and could be through E3-mediated ubiquitination of Smad4/adaptor protein complexes. Disruption of ELF (embryonic liver fodrin), a Smad4 adaptor protein, modulates TGF-beta signaling. We have found that PRAJA, a RING-H2 protein, interacts with ELF in a TGF-beta-dependent manner, with a fivefold increase of PRAJA expression and a subsequent decrease in ELF and Smad4 expression, in gastrointestinal cancer cell lines (P < 0.05). Strikingly, PRAJA manifests substantial E3-dependent ubiquitination of ELF and Smad3, but not Smad4. Delta-PRAJA, which has a deleted RING finger domain at the C terminus, abolishes ubiquitination of ELF. A stable cell line that overexpresses PRAJA exhibits low levels of ELF in comparison to a Delta-PRAJA stable cell line, where ELF expression is high compared to normal controls. The alteration of ELF and/or Smad4 expression and/or function in the TGF-beta signaling pathway may be induced by enhancement of ELF degradation, which is mediated by a high-level expression of PRAJA in gastrointestinal cancers. In hepatocytes, half-life (t(1/2)) and rate constant for degradation (k(D)) of ELF is 1.91 h and 21.72 min(-1) when coupled with ectopic expression of PRAJA in cells stimulated by TGF-beta, compared to PRAJA-transfected unstimulated cells (t(1/2) = 4.33 h and k(D) = 9.6 min(-1)). These studies reveal a mechanism for tumorigenesis whereby defects in adaptor proteins for Smads, such as ELF, can undergo degradation by PRAJA, through the ubiquitin-mediated pathway.

Animals↗
PubMed2004

Breast feeding and childhood hematological malignancy.

Breast milk is known to have anti-infective and immunomodulating effects on infants, but its association with childhood cancer has not been well studied. Artificial feeding may affect the immune response in carcinogenesis. In this communication the authors have reviewed different articles describing the association between breast feeding (BF) and subsequent development of childhood hematological malignancy. It appears that BF may have a protective effect on childhood cancer, both the duration of BF as well as the quantity of milk ingested is probably critical to the beneficial immunological effects of BF against childhood cancer if any.

Adolescent↗
PubMed2004

Anti-HIV and cytotoxic ruthenium(II) complexes containing flavones: biochemical evaluation in mice.

Ru(II) polypyridyl complexes containing 3-hydroxyflavone derivatives as coligands were screened for anti-HIV and cytotoxic activities against eleven tumor cell lines. In order to check the effect of flavones containing Ru(II) complexes in vivo on a mammal, a representative complex Ru(L)2(DMSO)2 x 5H2O (LH-3-Hdroxy-4'-benzyloxyflavone; M5) was orally administered to adult male mice. Its effects on protein content and LDH were studied in different tissues of the animal. The compound got absorbed and retained in the blood between 1-3 hr after feeding. As compared to the normal and DMSO control sets, tissue specific significant reversible changes in the protein content as well as in LDH activity were observed between 1-4 hr of treatment. However, on polyacrylamide gel electrophoresis, except some tissue specific transitory alterations, expression patterns of five LDH isozymes were unchanged after feeding the compound. The present results suggested that in addition to its potent cytotoxic and anti-HIV effects on cell lines in vitro, M5 inhibited LDH activity, but reversibly with a little effect on biosynthetic status of the enzyme in mice.

Animals↗
PubMed2002

Itih-4, a serine protease inhibitor regulated in interleukin-6-dependent liver formation: role in liver development and regeneration.

Inter-alpha-trypsin inhibitor-4 (Itih-4) is a liver-restricted member of the serine protease inhibitor family with diverse functions as an anti-apoptotic and matrix stabilizing molecule that are important throughout development. We investigate the functional role of Itih-4 in liver formation, regeneration (LR) and examine its role in calcium and hyaluronic acid binding. Itih-4 expression is prominent in early liver development at E9 and later at E16, being restricted to hepatoblasts, immature hepatocytes, and differentiated hepatocytes. We note a marked and differential increase in Itih-4 labeling in proliferating hepatocytes, compared with bile duct cells in liver explant cultures treated with interleukin-6 (IL-6). After partial hepatectomy, maximal Itih-4 expression occurs in a bimodal manner at 30 min and at 12 hr, with a predominant centrizonal distribution. There is no detectable binding of glutathione transferase-fusion Itih-4 protein to calcium and hyaluronic acid, indicating a possible requirement for posttranslational modifications for these functions. These results suggest that in LR, Itih-4 expression corresponds to that of immediate early genes and may contribute to the entry of normally quiescent hepatocytes into the early stages of the cell cycle. The markedly high expression of Itih-4 in early liver development and in explants treated with IL-6 suggests a prominent role for Itih-4 at key points in liver formation.

Animals↗
PubMed2001

Nitrate/nitrite reductase activity of sulfido/selenido bridged dinuclear ruthenium(III) complexes.

Series of dinuclear species [Ru(2)(L)(2)(LH)(2)-mu-S(2)Cl(2)], [Ru(2)(L)(2)(LH)(4)-mu-Se(2)Cl(2)] (L=L(1)H and L(3)H) and [Ru(2)(L(2))(2)(L(2)H)-mu-Se(2)Cl(2)].2H(2)O, where L(1)H, L(2)H and L(3)H represent for 2-mercapto-5-phenyl-1,3,4-oxadiazole, 2-mercapto-benzimidazole and 2-mercapto-benzothiazole, respectively, have been prepared and characterized by their elemental analyses and spectral (IR, UV-visible, 1H NMR and FAB mass) data. The diamagnetism of these complexes are indicative of an exchange coupled dinuclear ruthenium(III) species containing S(2)(2-) and Se(2)(2-) bridges. The complexes along with free heterocycles (L(1)H-L(3)H) as well as RuCl(3) x 3H(2)0 were tested for their nitrate and nitrite reductase activities. The electrochemical behaviour of the complexes showed irreversible oxidation peaks at +(1.04-1.40) V quite comparable to those reported for sulphido bridged complexes.

Electrochemistry↗
PubMed2001

Anti-HIV and cytotoxic activities of Ru(II)/Ru(III) polypyridyl complexes containing 2,6-(2'-benzimidazolyl)-pyridine/chalcone as co-ligand.

Ru(II)/Ru(III) polypyridyl complexes containing 2,6-(2'-benzimidazolyl)-pyridine or chalcone as co-ligands were synthesized and characterized previously (Mishra, L.; Sinha, R. Indian J. Chem., Sec. A 2001, in press. Mishra, L.; Sinha, R. Indian J. Chem., Sec. A, 39A, 2000, 1131). Their interaction with aqueous buffered calf thymus DNA was measured. (Novakova, O.; Kasparkova, J.; Vrana, O.; van Vliet, P. M., Reedijk, J.; Brabec, V., Biochem. 34, 1995, 12369 and these results prompted additional screening for anti-HIV (human immunodeficiency virus) activity against DNA replication in H9 lymphocytes and cytotoxic activity against eight tumor cell lines. The most active compounds were 17 in the former assay (EC(50) < 0.1 microg/mL and TI > 23.1) and 3, 8, 10, and 14 in the latter assay, especially selectively against the 1A9 ovarian cancer cell line (IC(50) = 4.1, 3.8, 3.6, and 2.5 microg/mL, respectively).

Anti-HIV Agents↗
PubMed2001

Smad proteins and hepatocyte growth factor control parallel regulatory pathways that converge on beta1-integrin to promote normal liver development.

Smads serve as intracellular mediators of transforming growth factor beta (TGF-beta) signaling. After phosphorylation by activated type I TGF-beta receptors, Smad proteins translocate to the nucleus, where they serve as transcription factors and increase or decrease expression of TGF-beta target genes. Mice lacking one copy each of Smad2 and Smad3 suffered midgestation lethality due to liver hypoplasia and anemia, suggesting essential dosage requirements of TGF-beta signal components. This is likely due to abnormal adhesive properties of the mutant hepatocytes, which may result from a decrease in the level of the beta1-integrin and abnormal processing and localization of E-cadherin. Culture of mutant livers in vitro revealed the existence of a parallel developmental pathway mediated by hepatocyte growth factor (HGF), which could rescue the mutant phenotype independent of Smad activation. These pathways merge at the beta1-integrin, the level of which was increased by HGF in the cultured mutant livers. HGF treatment reversed the defects in cell proliferation and hepatic architecture in the Smad2(+/-); Smad3(+/-) livers.

Active Transport, Cell Nucleus↗
PubMed2001

Ayurveda: a historical perspective and principles of the traditional healthcare system in India.

Ayurveda, the science of life, is a comprehensive medical system that has been the traditional system of healthcare in India for more than 5000 years. This medical system was well established around 2500 to 600 BC, when it evolved into 2 schools: the School of Physicians and the School of Surgeons, similar to allopathy. Charak Samhita, Susrut Samhita, and Ashtang Hridaya Samhita are the Senior Triad texts, and Madhav Nidan Samhita, Sarangdhar Samhita, and Bhavprakash Samhita are the Junior Triad texts. Around 600 BC. Ayurveda was branched into internal medicine; pediatrics; psychiatry; surgery; eye, ear, nose, and throat; toxicology; geriatrics; and eugenics/aphrodisiacs. The body is composed of 3 body doshas, 3 mental doshas, 7 dhatus, and malas. The harmony among the body doshas of vata (nervous system), pitta (enzymes), and kapha (mucus) and the gunas, or mental doshas (which are human attributes: satogun [godly], rajas [kingly], and tamas [evil]), constitutes health, and their disharmony constitutes disease. The management of illness requires balancing the doshas back into a harmonious state through lifestyle interventions, spiritual nurturing, and treatment with herbo-mineral formulas based on one's mental and bodily constitution.

History, Ancient↗
PubMed2001

Healthcare and disease management in Ayurveda.

Because the disharmony of mental doshas (satogun, rajogun, and tamogun) and body doshas (vata, pitta, and kapha) are the major cause of illness, the goal of illness management in Ayurveda is to bring back harmony among the doshas. The management includes clinical examination, diagnosis, and dietary and lifestyle interventions and treatment. The clinical examination consists of Astha Sthana Pariksha (8-point diagnosis: pulse-diagnosis, urine, stool, tongue, voice and body sound, eye, skin, and total body appearance examinations) and examination of the digestive system and the patient's physical strength. The treatment consists of cleansing (Panchkarma), palliation (improve digestion, remove toxic waste, fasting, observe thirst, exercise, sunbathing, and meditation), mental nurturing, and spiritual healing depending on the disturbed doshas and the patient's constitution. The preferred use of bhasms and herbal formulas over the respective metallic salts or the single herbs is discussed. This review suggests a great potential for integration of Ayurvedic therapies into the healthcare system in the United States.

Delivery of Health Care, Integrated↗
PubMed2000

Intratumoral therapy of cisplatin/epinephrine injectable gel for palliation in patients with obstructive esophageal cancer.

Obstructing esophageal cancer produces severe dysphagia with ensuing death within 90 days. Palliation is possible with modalities like stent placement, laser, and photodynamic therapy. However, these treatments have a high rate of complications, and the overall mortality is not altered. A new alternative treatment evaluated in this study is endoscopic intratumoral injection with cisplatin/epinephrine (CDDP/epi) gel. CDDP/epi gel injections were administered weekly for 3 to 8 weeks in nine patients, median age, 72 years; mean tumor volume (+/-SEM), 41.44 (+/-22.4) cm3. Eight patients had stage IV, and one had stage III esophageal carcinoma. The mean dysphagia score (+/-SEM) was 3.5 (+/-0.17). All patients were followed up until death. Dysphagia resolved in eight patients with reduction in mean dysphagia score (+/-SEM) from 3.5 (+/-0.17) to 0.75 (+/-0.28; p = 0.005). Tumor volume was reduced by 75% in one patient and by 50% in two patients. The median survival was 4 months. The longest follow-up has been 15 months (458 days). In this pilot study, intratumoral injection of CDDP/epi gel restored swallowing in eight of nine patients and was an effective and safe outpatient treatment in patients with obstructive esophageal cancer.

Adenocarcinoma↗
PubMed1999

Elf3 encodes a novel 200-kD beta-spectrin: role in liver development.

beta-spectrins are crucial for the maintenance of cell shape, the establishment of cell polarity, and the formation of distinct membrane domains. Our strategy for identifying genes important for hepatocyte polarity has been to utilize subtractive hybridization of early embryonic mouse cDNA liver libraries. As a result, we have cloned three isoforms of a novel beta-spectrin elf (embryonic liver beta-fodrin), and here we report the analysis of elf3, the longest isoform (8172 nt). ELF3 comprises 2154 residues with an overall similarity of 89.0% and 95.3% to mouse beta-spectrin (betaSpIIsigma1) at the nucleotide and amino acid level, respectively. ELF3 is characterized by an actin-binding domain, a long repeat domain, and a short regulatory domain remarkable for the absence of a PH domain. Linkage analysis reveals that elf3 maps to mouse chromosome 11 between D11Bir6 and D11Xrf477, a different chromosomal locus from that of the other four spectrin genes. Northern blot analysis utilizing an elf3 3'-UTR probe demonstrates an abundant 9.0-kb transcript in brain, liver, and heart tissues. Western blot with a polyclonal antibody against ELF identifies a 200 kD protein in mouse liver, brain, kidney, and heart tissues. Immunohistochemical studies demonstrate ELF labeling of the basolateral or sinusoidal membranes surface as well as a granular cytoplasmic pattern in hepatocytes. Antisense studies utilizing cultured liver explants show a vital role of elf3 in hepatocyte differentiation and intrahepatic bile duct formation. The differential expression, tissue localization, and functional studies demonstrate the importance of elf3 in modulating interactions between various components of the cytoskeleton proteins controlling liver and bile duct development.

Amino Acid Sequence↗
PubMed1999

Genomic structure, chromosomal mapping, and muscle-specific expression of a PH domain-associated intronless gene, cded/lior.

The aim of our study was to isolate novel gene(s) involved in cell differentiation and embryonic liver development. Mouse cded/lior was identified from subtraction hybridization of embryonic liver cDNA libraries as well as an adult mouse liver genomic DNA library. The full open reading frame of cded/lior encodes a 131-amino acid protein with 71.88% overall similarity to the PH domain of rat PLC-gamma1. A gapped search with the C-terminal region of CDED/LIOR revealed a 36-41% similarity to several proteins related to signal transduction and cell replication, such as ORC1 and KSR. Northern blot analysis of adult mouse tissues shows a strong 2.6-kb transcript restricted to heart and skeletal muscle. RT-PCR utilizing cded/lior-specific primers demonstrates cded/lior mRNAs in heart, brain, and liver tissue throughout mid-embryonic mouse gestation. cded/lior maps to the distal end of mouse Chromosome (Chr) 2. Analysis of the genomic structure for cded/lior demonstrated a single exon gene that is not an alternatively spliced isoform of PLC-gamma1. Analysis of the cded/lior promoter region revealed a high GC-content, high ratio of CpG/GpC, multiple GC-boxes, the lack of a TATA box, CTF/NFI element, and two MyoD-MCK binding sites. These characteristics are also found in several genes important in the regulation of cell growth or DNA synthesis, such as transforming growth factor-beta1, c-Ha-ras, nerve growth factor, epidermal growth factor receptor, and DNA polymerase beta. These results suggest that cded/lior is a mesoderm/muscle-specific transcript that may be involved in the mesodermal inductive and regulatory interactions required for liver formation and embryonic development.

Amino Acid Sequence↗
PubMed1998

Identification of mouse itih-4 encoding a glycoprotein with two EF-hand motifs from early embryonic liver.

An essential feature of cell differentiation is the specificity of signal transduction events from extracellular cues, which are considered to be conferred by scaffold, anchoring and adaptor proteins. Our aim was to identify important scaffolding proteins required for liver development. Utilizing subtraction hybridization of embryonic liver cDNA libraries, here we report the full length cDNA sequence for mouse itih-4 (Inter-alpha-trypsin inhibitor H4). Itih-4 encodes a 942 amino acid protein containing two EF-hand (helix-loop-helix) motifs with an unique short loop, with a potential calcium-binding function. Itih-4 is expressed as a strong 3.1-kb transcript in liver, to a lesser extent in lung and heart tissue. RT-PCR demonstrates itih-4 mRNAs abundantly in liver, less in heart and brain, during mid-embryonic gestation. These results suggest that itih-4 is a potential regulator for extracellular matrix proteins and plays a role during early embryonic liver development.

Amino Acid Sequence↗
PubMed1998

Role of insulin-like growth factor-I (IGF-I) receptor, IGF-I, and IGF binding protein-2 in human colorectal cancers.

The identification of novel autocrine/paracrine signaling pathways and possible markers represents an important component in the understanding of tumor growth control. In this study, we assessed the potential role of insulin-like growth factor-I (IGF-I), the IGF-I receptor (IGF-IR) and IGF binding protein-2 (IGFBP-2) in human colorectal cancer. Initial studies demonstrating increased IGF-I binding and IGF-IR density in human colon cancer tissue revealed that a component of iodinated (3-[125-I]iodotyrosyl) IGF-I (125I-ICGF-I) binding was not attributable to IGF-IR. Binding studies and Western blot analysis suggested that this second component of 125I-IGF-I binding could be due to IGFBP-2. Further analysis by a specific solution hybridization/RNase protection assay for IGF-IR mRNA levels, IGFBP-2 mRNA levels and in situ hybridization for IGFBP-2 localization, was carried out in nine patients with colon cancer. IGF-IR mRNA levels by RNAse protection assays were unchanged, whereas IGFBP-2 mRNA levels were increased 4-8-fold in patients with colon cancer compared to controls. Three patients with Dukes stage C disease had the highest levels of IGFBP-2 mRNA. In situ hybridization studies localized IGFBP-2 mRNA to malignant cells and not to the surrounding stromal cells, suggesting an autocrine role for IGFBP-2. The discrepancy between increased IGF-I binding, IGF-IR density, IGFBP-2 mRNA and the minimal modulation of the IGF-IR mRNA implies post-transcriptional regulation of IGF-IRs. Our results suggest that IGFBP-2 may be implicated in colon cancer metastases and prognosis. Its usefulness as a potential tumor marker should be further investigated.

Autoradiography↗