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Biomedical subjects

S Mukerjee

Publications and source records attributed to S Mukerjee.

At least 19 recordsLinked to original sources
PubMed2000

Identification of the immunoreactive peptide sequence for AgSK1, an adenocarcinoma-restricted antigen.

SK1, a human immunoglobulin M (IgM) monoclonal antibody was derived from regional nodal lymphocytes of a Dukes B colon carcinoma patient. The antigen recognized by the human monoclonal antibody (HuMab) SK1, termed AgSK1, was shown to be a two-chain glycoprotein with an apparent molecular weight range of 42-46 kDa and preferentially expressed by human adenocarcinomas, particularly human gastrointestinal malignancies. To identify the gene encoding the AgSK1 antigenic epitope, a cDNA expression library constructed in lambda gt22A using mRNA from the colon carcinoma cell line HT29 was screened and one of the isolated clones encoding a 1.5-kb cDNA, which showed strong immunoreactivity with HuMab SK1, was selected for further analysis. This clone consisted of an amino terminal open reading frame of 54 amino acids and the carboxyl terminal 20 amino acids of this protein coding region contained the antigenic epitope recognized by HuMab SK1.

Adenocarcinoma↗
PubMed1999

Co-expression of tumor antigens and their modulation by pleiotrophic modifiers enhance targeting of human monoclonal antibodies to pancreatic carcinoma.

Cocktails of human monoclonal antibodies (HuMAbs) have been used to increase the likelihood of identifying heterogeneous cancer cells. We utilized 3 HuMAbs termed SK-1, GM4, and GMA1, which recognized a 42-46 kDa two chain structure, a 57 kDa antigen, and the ganglioside GD3, respectively. An estimated two dozen cell lines were tested for the coexpression of these antigens and this was found to be present only on pancreatic carcinoma cell line, PANC-1; A 24 hr treatment of PANC-1 cells with interferon gamma (IFN gamma; 100 units), interferon beta (IFN beta; 1000 units), as well as interferon alpha (IFN alpha; 1000 units) resulted in roughly a four fold increase in the co-expression of the 42-46 kDa/GD3 antigens as well as the 42-46 kDa/57 kDa antigens. After a 4 day incubation the co-expression of these antigens progressed and IFN alpha treatment had the most pronounced effect, which was 8 fold higher than background for the 42-46 kDa/57 kDa antigens, whereas IFN beta resulted in a five fold antigen upregulation. The pronounced effect of vinblastine on the co-expression of the 42-46 kDa/GD3 antigens (4 fold on day 1 and, 10 fold on day 4) and 42-46 kDa/57 kDa antigens on PANC-1 (5 fold on day 1 and 7 fold over background on day 4) cells can be seen at concentrations as low as 10(-7)M. Colchicine and vincristine dramatically enhanced co-expression of these tumor antigens on day 4 but not on day 1 PANC-1 cells. The expression of these antigens was also found to be cell cycle dependent.

Antibodies, Monoclonal↗
PubMed1998

Characterization of human IgG1 monoclonal antibody against gangliosides expressed on tumor cells.

A human IgG1.k monoclonal antibody (MAb) designated GMA1 was developed by fusing pooled lymph node lymphocytes from cancer patients with the human lymphoblastoid cell line, SHFP-1. The GMA1 MAb reacted with several melanoma and neuroblastoma cell lines. Normal tissue derived from human brain and tumor-cell lines derived from colon, ovary, and breast were not reactive. FACS analysis performed using live cells demonstrated that the antibody recognizes a cell-surface antigen. Enzyme immunoassay (EIA) and thin layer chromatography (TLC) immunostaining with purified gangliosides indicated that the antibody has specificity for the major tumor associated gangliosides GD3, GM3, and GD2. GMA1 heavy and light chain genes were isolated by RT-PCR and a recombinant derivative of this human antibody was expressed in Chinese hamster ovary (CHO) cells. High-level antibody synthesis and secretion was achieved using a vector designed to maximize expression. FACS analysis and TLC immunostaining indicated recombinant GMA1 reacted with human tumor cell lines and gangliosides GD3, GM3, GD2 in a manner similar to the antibody produced by the hybridoma cell line, demonstrating that the specificity of the antibody was not altered during molecular cloning.

Amino Acid Sequence↗
PubMed1997

Surgery in India.

Surgical practice in India is mostly managed by the central and state governments and is totally government financed, offering free medical aid. However, with the economic growth and affluence of the middle-class population in urban areas, more and more hospitals, nursing homes, and clinics managed by the private sector are arising in cities and towns. Privately owned hospitals are built and managed by large industrial houses and trusts. It is essential, according to government directives, for these hospitals to have certain numbers of general beds that will provide for the economically weaker sections of the population. Medical insurance is popular amongst the urban population; in addition to well-established insurance companies, many new medical service reimbursement organizations are forming. Surgical care standards are uniformly high in the larger teaching institutions and hospitals run by the private sector in major cities in India, in which superspecialty surgical care that meets worldwide standards is available in addition to general surgical care. These hospitals are manned by surgeons holding master's degrees in general surgery, superspecialties, and subspecialties. In the hospitals and dispensaries in rural areas, only basic surgical facilities are available; for major surgical procedures, the patients are referred to the closest urban hospitals. Therefore, the government of India is placing more and more emphasis on building hospitals that offer better surgical facilities away from the cities and towns. A diploma course in surgery is run by the National Board of Surgery, and these diplomates are encouraged to practice more in rural areas and small hospitals. Economic constraints and the population explosion are the biggest hurdles to progress in surgical care, teaching, and research activities. With the advancement in education and growth of the economy, more and more multinationals are walking into the field of medical care, which is proving to be a great boon and providing a rapid increase in the health care expansion in this country. The World Health Organization and the World Bank are providing considerable aid for disease prevention, health care provision, and research activities.

Education, Medical↗
PubMed1997

Cloning and expression of the human tumor-specific antibody GM4.

The human monoclonal antibody GM4 was generated by fusing pooled lymphocytes from cancer patients with the lymphoblastoid cell line SHFP-1. Immunohistochemical staining of tumor and normal tissue indicated that this human IgG4 antibody preferentially reacted with melanomas and neuroblastomas. In this study, we demonstrate that GM4 recognizes a "vimentin-like" peptide sequence that we have termed AgGM4. To generate a recombinant derivative of this human antibody, we isolated and expressed the complete heavy and light chain genes. The entire coding sequence for both the heavy and light chains was isolated by RT-PCR using a set of degenerate 5' signal sequence specific primers and a 3' constant region primer. High level antibody synthesis and secretion was achieved in Chinese hamster ovary (CHO) cells using a vector designed to maximize expression. Western blot and FACS analysis indicated recombinant GM4 reacted with human tumor cell lines and AgGM4 in a manner similar to the antibody produced by the hybridoma cell line, demonstrating that the specificity of the antibody was not altered during molecular cloning.

Amino Acid Sequence↗
PubMed1997

Polypeptide levels increase during acute onset of hepatic porphyrias.

Hepatic porphyrias are characterized by neurological symptoms manifested by abdominal pain, neuropathies and mental aberrations. Porphyrins are ubiquitous and essential biochemical constituents of living beings acting as mediators of oxidation reaction in the metabolism of the steroid, drugs, environmental chemicals or as a mean of exchanging gases, such as oxygen and carbon dioxide between the environment and the tissue of the body using endogenous polypeptide properties. The different porphyrins arising from the arrangement of normal heme synthesis are characterized by an accumulation and excretion of specific intermediate porphyrins and/or of precursors exerting toxic effect, initiating cascades of generations of polypeptides, neurotransmitters and gut-brain axis peptide responsible for the symptoms of clinical status. We studied polypeptide levels in 27 patients (19 females, 8 males) presenting acute attack of hepatic porphyria: 2 with ALA dehydratase-deficient porphyria; 9 with acute intermittent porphyria; 12 with porphyria cutanea tarda and 4 with variegate porphyria. During acute attacks of porphyria, polypeptides were found to be constantly increased: vasoactive intestinal polypeptide (VIP); neurotensin (NT); substance P; pancreatic polypeptide; gastrin-releasing peptide; gastrin and motilin. Administration of the somatostatin (antagonizing polypeptide), which was undetectable or low before treatment, apparently alleviated the acute symptomatology. Elevated levels of polypeptides, at least partly, contribute to appearance of acute symptoms in porphyria patients.

Acute Disease↗
PubMed1996

Impaired antioxidant defense at the onset of psychosis.

Previous studies found peripheral activities of antioxidant enzymes to be abnormal in schizophrenic patients. It is not understood whether this is integral to the disease process or a result of long-term treatment with neuroleptics. Red blood cell activities of three antioxidant enzymes--superoxide dismutase, glutathione peroxidase, and catalase--were therefore examined in 14 drug-naive, first episode patients with a diagnosis of schizophrenia or schizophreniform disorder and 10 normal subjects. The patients had an average duration of psychosis of 4.46 days (SD 2.5). Superoxide dismutase activity was significantly lower in patients than in normal controls, with no difference between the groups in activities of the other two enzymes. Lower superoxide dismutase activity was associated with deterioration of school functioning from childhood to early adolescence and a history of poorer school functioning during early adolescence. These findings indicate a compromised antioxidant defense at the onset of psychosis, and suggest that oxidative injury might contribute to adverse developmental events in the pathogenic cascade of schizophrenia.

Adult↗
PubMed1996

Isotype-directed enrichment of B cells by magnetic beads in the generation of immunoreactive human monoclonal antibodies.

Pooled lymphocytes collected from cancer patients were mixed with a biotinylated murine MAb specific to human IgG4. To this were added streptavidin-conjugated magnetic beads. After magnetically separating the bead-lymphocyte complex, the B cells were washed and fused with the WIL-2 derived human fusion partner, SHFP-1. Subsequently derived human-human hybridomas were screened for IgG4 immunoreactivity to target tumor cell lines. Several hybridomas reacted with a variety of malignant cell types, including melanoma, neuroblastoma, and pancreatic tumor cells. One hybridoma in particular, designated SC-GM4, recognized an antigen by Western blot with an apparent molecular weight of 57 kDa. This facile approach of magnetically separating selected populations of lymphocytes should be relatively simple to apply to other antigens and antibodies to preselect the type, class, and properties of the desired MAb.

Antibodies, Monoclonal↗
PubMed1995

Induction of human breast cancer-specific antibody responses in cynomolgus monkeys by a murine monoclonal anti-idiotype antibody.

We have generated and characterized a murine monoclonal anti-idiotype (Id) antibody, designated 11D10, which biologically and antigenically mimics a distinct and specific epitope of the high molecular weight human milk fat globule primarily expressed by human breast and some other tumor cells at high density. This epitope is identified by mAb BrE1, which was used as the immunizing antibody or Ab1 to generate the anti-Id (Ab2) 11D10. 11D10 induced antitumor immune responses across species barriers, i.e., in mice and rabbits. In preclinical studies, cynomolgus monkeys were immunized with 2 mg of either 11D10 or the isotype- and allotype-matched control Ab2 3H1 after precipitation with aluminum hydroxide. All monkeys developed high titers of antibodies against the immunizing mouse immunoglobulin. Immunization with 11D10 induced anti-anti-idiotype antibodies (Ab3) which reacted with breast cancer cell lines but not with control T-cell and melanoma cell lines. The Ab3 shared idiotypes with BrE1 (Ab1), as demonstrated by their ability to inhibit 11D10 binding to BrE1. The Ab3 obtained with 11D10 bound specifically to human milk fat globule antigen and competed with BrE1 for binding to breast cancer cell lines, suggesting that Ab1 and Ab3 may bind to the same epitope. In addition, Id-specific cellular immune responses were demonstrated in monkeys immunized with 11D10 by T-cell proliferation assays. These results indicate that aluminum hydroxide-precipitated anti-Id 11D10 can induce breast cancer-specific antibodies in nonhuman primates and can serve as a potential network antigen for breast cancer patients.

Animals↗
PubMed1995

Analysis of the sequences of human beta-1,4-galactosyltransferase cDNA clones.

UDP-galactose:beta-1,4 N-acetyl glucosamine galactosyltransferase (4 beta GT) is a promising tumor marker for ovarian cancer. To study the role of 4 beta GT in malignant transformation at the molecular level human 4 beta GT cDNA and genomic clones were isolated and analyzed. For the isolation of 4 beta GT cDNA and genomic clones, a human fetal liver cDNA library in lambda gt11 and a human genomic library in EMBL-3B vectors respectively were screened using a 4 beta GT cDNA insert as the probe. Complete sequence of the cDNA clones were determined by subcloning in plasmid vectors, and compared with the published sequence of human liver 4 beta GT. Presence of various 4 beta GT exons in the genomic clones were determined by Southern blot analysis using specific oligodeoxynucleotide probes. Among the 5 cDNA clones isolated, 2 clones GTN 6 and GTN 17 were sibling clones and had a nucleotide sequence identical to the published 4 beta GT cDNA sequence, except at the 3'-end, where these clones had 7 unique nucleotide sequences. One cDNA clone, GTN2 also had a nucleotide sequence identical to that of 4 beta GT, except for 3 G residues at the 5'-end. One cDNA clone, GTN 1, had a unique sequence at the 5'-end comprising of 74 nucleotides. Another clone, GTN 20, was unrelated to 4 beta GT. Analysis of genomic clones showed that 4 beta GT exons 3, 4, 5 and 6 were present in a 14 kb genomic clone, EMGT-4. Exon 1 was present in a separate 16 kb clone, EMGT-6.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1994

Interferon inhibitor factor predicting success of plasmapheresis in patients with multiple sclerosis.

Interferons (IFN) are biological molecules with antiviral, antiproliferative, and immunomodulatory actions. Plasmapheresis (PP) combined with IFN therapy in 24 multiple sclerosis (MS) patients was associated with a rapid increase in detectable IFN levels. We describe the presence of a detectable factor in the serum of MS patients which decreases the efficacy of IFN therapy in these patients. We call this factor "interferon inhibitor factor" (IIF). Standard IFN assay indicates inhibition of WISH cell protection by IFN owing to the presence of IIF in patient's serum. Similar results were also obtained with human fibroblast and human leukocyte IFNs. The best results were obtained with an IFN mixture; results with 1:20 diluted patient's sera showed elevation of 120% greater than 1:10 dilution. With 1:40 dilution, an elevation of 1,041% was noticed. The IIF from patient sera collected during PP was purified and characterized. Native gel electrophoresis of IIF indicates a single protein band; further analysis on SDS gels indicates two bands at the 200 and 21-kD range. ELISA failed to reveal the presence of any anti-IFN antibodies. This study demonstrates the presence of IIF in MS patients' sera which are removed from the circulation by PP. Removal of IIF from circulation was associated with increased IFN levels and clinical improvement as measured by Kurtzke's disability status scale (KDSS).

Adult↗
PubMed1994

Plasmapheresis combined with interferon: an effective therapy for multiple sclerosis.

The rationale for the use of interferon (IFN) in the treatment of multiple sclerosis (MS) is based on its recognized antiviral and immunomodulating actions. The pathogenesis of MS is believed to be due to an immunologic response in a genetically predisposed individual, localized within the central nervous system white matter, and triggered by exposure to an environmental agent such as a virus. Based on our personal experience we find that the efficacy of IFN therapy is hampered in MS patients by the presence of an interferon inhibitor factor (IIF) in the patients' sera which we have isolated and characterized. When plasmapheresis (PP) was done on 24 MS patients with intermittent 3-day administration of IFN-alpha and human leukocyte IFN, marked increase of IFN in 18 patients and modest increase in three patients correlated with clinical improvement. Three clinical nonresponders showed no increase in IFN levels following therapy. The ability to remove IIF and lymphokine inhibitor factor (LIF) by PP may explain the successful treatment of our patients. We describe the evaluation of helper T cells, suppressor T cells, HLADR antigen, natural killer cells, and monocyte/macrophage cell populations by flow cytometry before and after PP. A significant increase in these immune-competent cells correlated with marked improvement in Kurtzke disability status scale in 13 patients, while eight stabilized. Patients showing progression of the disease either showed decrease or no change in these parameters after therapy. Encouraging results from this pilot study suggest that PP combined with immunomodulatory regimens of IFN may be an effective therapy for MS.

Adult↗
PubMed1992

Plasma cholinesterase isozymes and REM latency in schizophrenia.

The relation between electroencephalographic sleep parameters and plasma cholinesterase isozymes was examined in a group of 19 unmedicated schizophrenic patients. Rapid eye movement (REM) latency was found to be significantly inversely correlated with isozyme 3 (mainly acetylcholinesterase). The results are discussed in relation to cholinergic involvement in the regulation of REM sleep and in the pathophysiology of schizophrenia.

Adult↗
PubMed1992

Biochemical analysis of jejunal brush border membrane of golden hamster: pathogenic modulations due to ancylostomiasis.

The common hookworm (Ancylostoma ceylanicum) infection of humans was studied in golden hamsters model system. Significant biochemical modulations were observed in hamster jejunal brush border membrane (BBM), the primary site of infection. Analysis of BBM at the peak of infection (3-weeks) revealed a marked decrease in the activities of sucrase, lactase and maltase, while activities of alkaline phosphatase, (Ca2+ + Mg2+)-ATPase and gamma-glutamyl transpeptidase were increased. Kinetic studies conducted with maltase, a superficially localised enzyme of jejunal BBM, revealed loss of enzyme active site during the infection. Among other constituents, the levels of cholesterol and triglycerides were significantly decreased with slight increase in phospholipid content in the infected animals. The hookworm infection also caused a decline in total hexose content indicating an altered membrane glycocalyx. Conversely, there was significant enhancement of hydroxyproline and sialic acid contents. SDS-PAGE analysis showed an enhancement in both low and high molecular weight proteins in jejunal BBM preparations of the infected group. Gel electrophoresis of glycoproteins further revealed the appearance of two additional peaks in the low molecular weight region and concomitant disappearance of a peak in the high molecular weight region. These results strongly support the view that the hookworm infection causes severe damage not to the site of attachment alone but also to the entire cell lining of the jejunum and therefore could influence overall digestion and absorption.

Ancylostomiasis↗
PubMed1990

Murine monoclonal anti-idiotype antibody as a potential network antigen for human carcinoembryonic antigen.

Carcinomas of the gastrointestinal tract are not curable by standard therapies. Thus, new therapeutic approaches for this disease are needed. This study proposes the use of anti-Id mAb as Ag substitutes to induce anti-tumor immunity in gastrointestinal cancer patients. Recently, we have generated and characterized one monoclonal anti-Id antibody, designated 3H1 (Ab2), which mimics biologically and antigenically a distinct and specific epitope of the 180,000 m.w. carcinoembryonic antigen (CEA) primarily expressed in high density by human pancreatic and colonic tumor cells. This epitope is unique to CEA and not present on other CEA-related lower m.w. members of the Ag family also found on normal tissues. The antigenic determinant as defined by the mAb 8019 (Ab1) against which the Ab2, 3H1 was raised, is absent on normal adult tissues by immunoperoxidase staining and haematopoietic cells including granulocytes by flow cytometry analysis. Anti-Id (Ab2) 3H1 induced CEA-specific antibodies in mice and rabbits. The immune sera from both mice and rabbits competed with Ab1 for binding to the colon carcinoma cell line LS174T and inhibited the binding of radioiodinated Ab1 to Ab2. This indicates that anti-anti-Id (Ab3) in mice and rabbits share idiotopes with Ab1 (8019). Furthermore, monoclonal Ab3 that bind to CEA have been generated from mice immunized with 3H1. The Ab3 (both polyclonal as well as monoclonal) immunoprecipitated the same 180,000 m.w. CEA as Ab1 (8019) by Western blotting analysis and showed almost identical immuno-staining patterns as Ab1 on colonic adenocarcinoma tissue sections from several patients. Collectively these data suggest that Ab2 3H1 could potentially be used clinically as a network Ag for immunotherapy of patients with CEA positive tumors.

Adenocarcinoma↗
PubMed1990

Hepatic microsomal cytochrome P450 system during experimental hookworm infection.

Experimental infection of golden hamsters with the hookworm, Ancylostoma ceylanicum, caused a profound decline in the hepatic microsomal cytochrome P450 content. Concomitant decrease was also noticed in aminopyrine N-demethylase and benzo[a]pyrene hydroxylase activities. However, aniline hydroxylase activity was only marginally elevated during the infection. Microsomal markers, viz., cytochrome b5, NADH-cytochrome-c reductase, and glucose-6-phosphatase, were not significantly altered. Hepatic tissue exhibited an accumulation of lipids, especially phospholipids, triglycerides, and cholesterol, resulting in fatty necrosis around the central vein region. Isolated hepatic microsomes showed a decrease in phosphatidylcholine content. Impairment in hepatic mixed function oxidase (MFO) activities was further confirmed by prolongation in hexobarbital sleeping time and zoxazolamine-induced paralysis. The hepatic MFO system of A. ceylanicum-infected hamsters responded qualitatively and quantitatively in a manner similar to that of control hamsters, upon stimulation with selective chemical inducers like phenobarbitone and 3-methylcholanthrene. Kinetic and in vitro substrate binding studies revealed that for aminopyrine the substrate affinity and the maximum enzyme activity (Vmax) were decreased, while for aniline the binding affinity was decreased and the binding capacity was enhanced. Results indicate specific/selective impairment of the hepatic microsomal cytochrome P450 system during hookworm infection and may have many practical implications in toxicology and pharmacology.

Ancylostomiasis↗
PubMed1990

Molecular basis of hyperlipidemia in golden hamsters during experimental infection with Ancylostoma ceylanicum (Nematoda:Strongylidae).

An infection of golden hamsters with Ancylostoma ceylanicum, a hookworm parasite, induced profound hyperlipidemia, particularly hypertriglyceridemia, and the effect was directly related to the degree of infection. A significant increase was also noticed in serum cholesterol and phospholipid levels. The appearance of lipoprotein-X, an abnormal low density lipoprotein, was detected in the serum of hookworm-infected animals. The hyperlipidemia was further characterized by an increase in very low density lipoproteins (VLDL) and low density lipoproteins (LDL) with a concomitant decline in high density lipoproteins (HDL). Decreased lipolytic activities, especially triglyceride lipase, in hepatic tissue and induction of lipolytic activities in intestine and adipose tissues indicated mobilization of fats from adipose and jejunum with a defective removal of triglyceride-rich lipoproteins in hepatic tissues. Accumulation of lipids in liver and depletion in adipose tissue supported these results. The derangement may have a significant effect on host parasite interaction and is an important pathophysiological feature occurring during experimental ancylostomiasis.

Ancylostomiasis↗