Biomedical subjects

Joydeep Mukherjee

Publications and source records attributed to Joydeep Mukherjee.

12 recordsLinked to original sources

PubMed2006

Production and purification of a bioactive substance inhibiting multiple drug resistant bacteria and human leukemia cells from a salt-tolerant marine Actinobacterium sp. isolated from the Bay of Bengal.

Four marine actinobacteria tolerant to 200 g NaCl l(-1) were screened for antibacterial activity against eight patient-derived multiple drug resistant (MDR) bacteria. The active compound (MW 300.2, predicted molecular formula C(20)H(28)O(2)) from an actinobacterium, was inhibitory to three Gram-positive and three Gram-negative MDR bacteria, seven non-clinical Gram-positive, four Gram-negative bacteria and five fungi (MIC: 3.5-4.0 microg ml(-1)). Also, 54% of human leukemia (HL-60) cells were killed by the compound at 0.05 microg ml(-1). Bioreactor production demonstrated unusual primary metabolite kinetics. Molecular phylogenetic analysis showed this typical intertidal inhabitant to be a member of the Streptomyces genus and distinct from other salt-tolerant actinobacteria. As no compound was found to match the properties in several electronic databases, our screening strategy should increase the possibility of discovering bioactive molecules from rare actinobacteria.

Actinobacteria↗

PubMed2006

Purification and characterization of an extracellular, uracil specific ribonuclease from a Bizionia species isolated from the marine environment of the Sundarbans.

The first ribonuclease (RNase) from the Cytophaga-Flavobacterium-Bacteroides phylum, dominant in the marine environment, and also from the first Bizionia species isolated from the tropics was purified and characterized. Extracellular RNase production occurred when the culture medium contained 5-7% (w/v) NaCl. The 53.0 kDa enzyme was purified 29 folds with a recovery of 4% and specific activity of 630unit/mg protein. The pH and temperature optima are 6.5 and 35 degrees C, respectively and the enzyme retains more than half of its activity (relative to optimal assay conditions) after 1h pre-incubation separately with 5% (w/v) NaCl or from pH 5.0 to 8.5 or at 50 degrees C. Dithiothreitol and beta-mercaptoethanol do not inhibit whereas human placental RNase inhibitor protein halves the RNase activity. While Mg(2+), Ba(2+) and Ca(2+) enhanced the enzyme activity, Fe(2+), Cu(2+) and Hg(2+) inactivated it. This RNase degrades uracil containing nucleic acids only. Our isolate could be a novel renewable source of deoxyribonuclease (DNase)--free RNase enzyme.

Bacterial Proteins↗

PubMed2006

ENU administration causes genomic instability along with single nucleotide polymorphisms in p53 during gliomagenesis: T11TS administration demonstrated in vivo apoptosis of these genetically altered tumor cells.

Advancement of molecular analysis of neoplastic cells demonstrated that multiple genetic changes are associated with the development of tumors. Cancer cell must exhibit a mutator phenotype, which is likely to be responsible for the genomic instability found in cancer tissues. The mutator phenotype, such as defective mismatch repair, is known to cause microsatellite instability, which is associated with certain cases of sporadic cancer. Previously many studies have been carried out to determine the relationship between microsatellite instability and human brain tumors. However information on genomic instability in the animal model of brain tumor is still very limited. In the present course of investigations we genetically characterized our ENU induced brain tumor animal model by using PCR based randomly amplified polymorphic DNA (RAPD) analysis and restriction fragment length polymorphism (RFLP) with three microsatellite probes. ENU induced tumors demonstrated genetic instability, including some microsatellite instability. As single nucleotide polymorphisms of the tumor suppressor gene p53 were associated with diverse types of human cancer, we examined the p53 gene of the tumor cells isolated from ENU induced brain tumor animal model, by PCR based RFLP method in p53 exon-2, -3 and -4. In these studies we showed that the restriction site of p53 exon-3 and 4 were mutated in ENU induced brain tumor indicating a genetic defect associated with ENU induced tumorigenesis. In the therapeutic part, we confirmed the anti-tumor property of T11TS/S-LFA-3 in the ENU induced genetically altered cells. Histological evidences, cytotoxic study, PI-FACS cell-cycle analysis and TUNEL assay confirmed the apoptotic death of glioma cells by T11TS treatment in which p53 is mutated. From the present study we can conclude that ENU administration causes genomic instability along with mutations in p53 during the process of gliomagenesis. Whereas, T11TS/S-LFA3 demonstrated the potential to induce apoptosis of these tumor cells even when p53 is mutated and thus showed its immense potential to be an anti-neoplastic probe against p53 mutated diverse types of tumors.

Alkylating Agents↗

PubMed2005

T11TS/S-LFA3 induces apoptosis of the brain tumor cells: a new approach to characterise the apoptosis associated genetic changes by arbitrarily primed-PCR.

Genetic alterations in ethyl nitrosourea (ENU) induced brain tumor model were analysed by simple PCR based technique with arbitrary primers. T11TS/SLFA3 was established previously as a potent immune stimulator with antineoplastic property in experimental glioma model. The goal of this study was to reveal whether T11TS induces apoptosis of the neural neoplastic cell and to decipher the DNA polymorphism level of the cells undergoing apoptosis. The results clearly establish the apoptogenic role of T11TS/S-LFA3 and along with the detection of cancer associated genomic instability, AP-PCR analysis is useful for the detection of DNA level fragmentation, a unique feature of apoptosis.

Animals↗

PubMed2005

Sheep erythrocyte demonstrated better effect than IL-2 and IFN-gamma as biological response modifier against glioma in experimental model.

The significant insights into the immunobiology of central nervous system (CNS) and brain tumor have opened up the feasibility of applying 'Immunotherapy' as an alternative to the poor prognosis of malignant brain tumor with conventional therapeutic approaches. Though cytokines like IL-2 and IFN-gamma used against glioma showed some favorable results by eliciting Th1 type immune response, a proper immunotherapeutic agent is still to be searched for. Sheep erythrocyte (SRBC), a corpuscular antigen showed a better therapeutic efficacy in terms of enhanced survival and augmentation of cell mediated immunity (CMI) in a glioma model developed by chemical carcinogen ethyl nitrosourea. Histological findings revealed most efficient glioma rejection in SRBC and combination biological response modifier (BRM) treated groups. Simultaneously E-rosetting, cytotoxicity of lymphocytes, phagocytosis and antigen presenting capacity of myeloid cells established the better therapeutic efficacy of SRBC alone than other BRMs viz. IL-2 and IFN-gamma. Even the effect of combination therapy of different BRMs showed marginal differences in facilitating glioma reduction than the single use of SRBC. These findings emphasized the application of SRBC as an exogenous BRM having the potential as a rational therapeutic adjunct against glioma.

Animals↗

PubMed2004

CD2-SLFA3/T11TS interaction facilitates immune activation and glioma regression by apoptosis.

OBJECTIVE: Exogenous application of T11TS/SLFA3 in glioma model had shown the regression of tumor load through immunopotentiation. The mechanistic module of this interaction on immunological synapse formation and resulting effect in glioma regression is searched for delineating immunotherapeutic efficacy of T11TS. METHODS: After purification of T11TS/SLFA3 from sheep erythrocytes the glycoprotein was characterized by SDS-PAGE analysis and glycoprotein staining. The modulatory effect of T11TS application on glioma animals were studied by CD2 and MHC class II expression on peripheral lymphocytes, PMN, macrophages and intracranial microglia by flowcytometric analysis. Finally apoptotic killing of brain cells were studied through annevin-V expression and measuring fragmented cytoplasmic DNA by ELISA. RESULTS: Compared to healthy normal counter-parts the CD2 receptor downregulation by ENU treatment in lymphocytes and PMN were upregulated with three consecutive doses of T11TS. Splenic antigen presenting macrophages and intracranial mocroglia had shown CD2 and MHC class II modulation simultaneously in their different subtypes. These receptor studies revealed significant boosting of the immune competent cells most effectively in second dose of T11TS whereas the third dose had some regulatory effect. Sharp increase of apoptosis in brain cells was found by phosphatidylserine externalization and presence of fragmented DNA in cytoplasm with application of T11TS in consecutive doses as a result of immune potentiation. CONCLUSION: Receptor studies revealed modulation of CD2 and MHC class II, two important constituents of immunological synapse successfully help to form the TCR-p-MHC complex and provide required co-stimulation for activation. Potentiated immune effector machinery was then directed to abrogate glioma by apoptosis signifying T11TS as an immunotherapeutic probe.

Animals↗

PubMed2004

Immunotherapeutic effects of T11TS/S-LFA3 against nitrosocompound mediated neural genotoxicity.

Nitrosocompounds formed by the interaction of nitrites and secondary amines are neurotoxic in human and different rodent species. Human exposure of nitrosocompounds are widespread affected by different modes like nitrite/nitrate preserved foods, beverages like beer, formed in the stomach following uptake of the precursors nitrates, nitrites and secondary amines. The productions of alkylating metabolites during the breakdown of nitrosocompounds are the causative agents for the neurotoxic changes of the neural cells. An attempt has been made in our lab to study the effect of nitrosocompound mediated toxicity and the gradual toxic effects of these neurotoxic agents to transform the normal glial cells to a neoplastic one. The present study indicated that a transmembrane glycopeptide of sheep red blood cell (SRBC), known as S-LFA3 or T11 target structure (T11TS) applied to nitrosocompound induced animals manifesting a full grown intracranial malignancy can revert back tumor-bearing condition to the normal physiological state. Young Druckray rat of both sexes aging 3-5 days were injected with N'-N'-ethyl nitrosourea (ENU) intraperitoneally (i.p.) at a single dose of 80 mg/kg body weight to simulate nitrosocompound mediated neurotoxicity. 2-,4-, 6-, 8-, and 10-month-old neonatal ENU induced animals were sacrificed for growth kinetics, functional immunological parameters and receptor studies to hint at the changes during tumor development. In order to determine the immunomodulatory role of T11TS, 7-month-old ENU induced animals were injected with T11TS at a dose of 0.41 mg/kg body weight, in three consecutive doses at an interval of 6 days maintaining normal control as untreated control and ENU induced animals of age-matched rats as tumor-bearing control. All the immunological parameters, growth kinetic study, receptor-based study by FACS directly established the immunomodulatory, anti-toxic and anti-tumor property of T11TS/S-LFA3. Finally, formation of DNA ladder along with the FACS-based apoptosis study clearly indicated that T11TS is a potent apoptotic inducer in neoplastic neural cells.

Adjuvants, Immunologic↗

PubMed2004

Advances in the biology of astrocytomas.

PURPOSE OF REVIEW: Conventional surgery, radio- and chemotherapy have failed to significantly improve the prognosis of patients with malignant astrocytomas--hence the need for understanding their molecular biology. Harvesting this understanding to yield novel biological targeted therapies has approached the clinical doorstep. Therapeutic efficacy will likely require combinatorial therapy involving biologicals and conventional therapies, with small incremental efficacy in selected sub-groups. This review highlights some of the findings over the past year (June 2003-2004) that have contributed to this slow but essential journey towards our understanding of the biology of astrocytomas. RECENT FINDINGS: The accumulation of loss and/or gain of function molecular alterations underlying astrocytoma formation, progression and key growth parameters including proliferation, angiogenesis, apoptosis, invasion and resistance are emerging. These alterations involve those regulating the growth factor/receptor and downstream signaling networks, cell cycle, immune modulators and other key biological processes. The advances are facilitated by interactions amongst clinician and basic scientists, in both academia and industry. They have incorporated high-throughput bioinformatics analysis of genomic and expression array data, the emerging field of proteomics and development of various genetically engineered models of astrocytomas. SUMMARY: Astrocytomas, like other cancers, are a result of several molecular alterations, some of which strongly correlate to their pathological grade. However, molecular heterogeneity exists between astrocytomas of similar grades and likely between varying micro-environmental regions of a single tumor. Characterization of the molecular signature of an astrocytoma and linking with the appropriate 'tailored' therapie(s) is the hope of the future.

Animals↗

PubMed2002

Preclinical Changes in Immunoreactivity and Cellular Architecture during the Progressive Development of Intracranial Neoplasms and an Immunotherapeutic Schedule with a Novel Biological Response Modifier, the T11TS / S-LFA3.

Among neoplasms, brain tumors are particularly " difficult to treat" because of the partial immune privileged status of the brain and the presence of the blood brain barrier (Selmaj, 1996). Many details of progressive development of brain tumors remain unexplored and elucidation of consequent changes of the immune system with correlated cellular architecture and cell kinetics were the major objectives of the present course of investigations. Our studies have indicated that the primary resistance by the immune system to a growing tumor declines after a certain point, resulting in an immune suppressed state in a tumor bearing individual. The poor prognosis of malignant brain tumors with classical treatments like surgery, radiotherapy and chemotherapy has led to interest in immunotherapeutic protocols. In the present study, an attempt was made to determine the immunomodulatory and antitumor properties of a transmembrane glycopeptide of sheep red blood cells (SRBCs), known as S-LFA3 or T11TS. Young Druckray rat of both sexes aged 3-5 days were injected with N'-N'-ethyl nitrosourea (ENU) (i.p) to induce brain tumors and at 2,4,6,8 and 10 months of age were sacrificed for study of survival, tumor growth kinetics and immunological parameters like lymphocyte rosette formation, denoting CD2 - CD58 interactions and phagocytosis by peripheral macrophages and PMN hint at the changes during tumore development. In order to determine the immunomodulatory role of T11TS, 7 month old ENU induced animals and controls were injected with the compound (1 ml., i.p). The data obtained indicate that administration of T11TS results in increased survival of rats along with a decrease in growth kinetics of tumor cells to the normal level when compared to ENU induced animals of the same age. Pointers to mechanisms involving immunological investigations at the cellular level in these animals indicated improved lymphocyte function in terms of E-rosetting, augmented cytotoxicity and enhanced PMN and macrophage function in terms of phagocytosis. Finally histological examination showed complete reversal from the hyperplastic state to normal cellular homeostasis, indicating antitumor efficacy of T11TS, correlating very well with the data from survival and cell kinetic studies.

Journal Article↗

PubMedDate not supplied

Evaluation of anti-tumor property of specific and non-specific BRMs in experimental gioma by assessing the microglial cell functional and phenotypic modulations.

BACKGROUND: Microglial cells are considered to be the chief immunomodulatory cells of the brain. These cells play a crucial role against various neurodegenerative diseases. When modulated microglia have been shown to exert a potential anti-tumor immune response against brain neoplasms. Although several specific BRMs like IL-2, IFNgamma have been shown to modulate the microglia to get an effective anti-tumor immune response, associated toxicities and detrimental side effects have posed severe limitation in there use particularly for therapeutic purposes. OBJECTIVES: In the present study, attempts have been made to elicit the modulations of microglia cell function and phenotypic expression following specific (IL-2, IFNgamma and a novel nonspecific BRM (corpuscular antigen) in order to determine their anti-tumor property in experimental glioma model. MATERIALS AND METHODS: Brain was experimentally induced in young Druckray rats of both sexes with N-N-ethyl nitroso urea (ENU). These ENU treated animals were administered with both specific and nonspecific BRMs like IL-2, IFNgamma and SRBC either singly or in combination 5 months after ENU administration and after ascertaining its degree of malignancy. RESULTS: Microglial cells separated from different experimental groups were found to be positive for CD11b, MHC II, CD4 and negative for GFAP.FACS analysis demonstrated that different subtypes of microglial cell populations (CD25+, MHC II+ and CD25+MHC II+) in the brain tissue based on phenotypic expression, which were downregulated in tumor bearing animals, and subsequently restored with increased expression, particularly with SRBC administration. The Scanning Electron Microscopic (SEM) study also depicted modulation of cellular morphology of microglial cell predominantly with SRBC administration. Studies conducted ton evaluate immunological functions at the cellular level showed increased antigen presenting caopacity of microglial cell with SRBC administration, which was significantly greater then IL-2, IFNgamma and combined doses (E2_S). However phagocytic functions of microglial cells were found not to be significantly modulated with BRM treatment. CONCLUSION: The results suggest that the nonspecific BRM SRBC can exert greater modulatory effect on microglila cell function and phenotypic expression than the other BRMs used, and in doing so culminate in a potent anti tumor immune response in experimental glioma with compatible tolerance profile.

Animals↗

PubMedDate not supplied

The first cross sectional survey on intracranial malignancy in Kolkata, India: reflection of the state of the art in southern West Bengal.

Recent increase in the occurrence of intracranial malignancies and poor performance of therapeutic measures have established the disease as an important concern of medical sciences. The lack of information about the disease pattern throughout India creates problems for maintaining community health for prevention. The present study on the hospital population of Kolkata was conducted to determine the incidence pattern of the disease in the population of southern West Bengal, focusing on distribution with age, sex, occupation and religion in different districts of the region, and characterizing diagnostic and therapeutic measures. Among a total of 39,509 cancer patients from 21 health centers of Kolkata, 2.4% had brain cancers and among these more than 60% are gliomas. A cross-sectional study for a period of 3 years reported the occurrence of 15 types of intracranial malignancy, which demonstrated astrocytomas (36.8%), glioblastoma multiforme (GBM) (7.9%) and meningiomas (11.6%) to be predominant. Brain tumors occur more frequently in males with few exceptions and the incidence was found to be highest among the 40-49 year old group (20.2%). No specific trend for religion and occupation was apparent. However, the district wise distribution showed maximum incidences among industrial areas, namely, Kolkata (33.1%), North 24-Parganas (18.2%), Howrah (9.3%) and Hoogly (7.6%). Diagnosis of the disease was by CT scan, MRI and histological identification (pre and post operative). Therapeutic procedures rely mainly on surgery and radiotherapy, whereas chemotherapy was used as an adjuvant for about 10% of the cases. Evaluation of the scenario regarding intracranial malignancy in this region was a long awaited requirement which should ultimately serve an important function in pointing to risk zones within the population and allow better control measures to be introduced for the disease.

Adolescent↗

PubMedDate not supplied

Immunotherapy with T11TS / S-LFA-3 specifically induces apoptosis of brain tumor cells by augmenting intracranial immune status.

BACKGROUND: Immunopotentiating agents are the best options in cancer therapeutics because they can specifically destroy tumor cells via immunocytes, which are mostly apoptotic in nature. Previously, immunotherapy with T11TS / SLFA-3 in a ethyl-nitrosourea (ENU)-induced animal model (Druckrey rats) of neural neoplasm showed a significant tumor mass destruction by augmenting the cellular immune status. MATERIALS AND METHODS: The modulations of the peripheral as well as neural immune systems after T11TS administration were monitored by assessing the CD4+ and CD8+ lymphocytes, along with the cytotoxic activity of splenic and brain infiltrating lymphocytes (BIL). The rate of apoptosis of the tumor cells, microglial cells (Mg) and BIL were measured by flow cytometry-based propidium iodide analysis and TUNEL assay. RESULTS: Cell cycle phase distribution analysis by propidium iodide -FACS and TUNEL assay revealed that T11TS administration gradually increased the number of apoptotic brain tumor cells and, at the same time, decreased the number of dividing cells. Up-regulation of the CD4+ and CD8+ lymphocytes were observed after T11TS administration in ENU - induced immunosuppressed animals. A gradual increment of cytotoxicity of splenic and BIL was also demonstrated after successive administration of T11TS. CONCLUSION: These data strongly support the specific apoptosis-inducing role of T11TS in experimental brain tumor cells. Apoptosis of BIL and Mg, that occurred to a much lower level, can be explained in terms of changes in the neural immune system before and after T11TS application.

Animals↗