Samar Kundu - Academia.edu (original) (raw)
Papers by Samar Kundu
METHODS FOR DETECTING ORGANISMS AND ENZYMATIC REACTIONS USING RAMAN SPECTROSCOPY techniques to id... more METHODS FOR DETECTING ORGANISMS AND ENZYMATIC REACTIONS USING RAMAN SPECTROSCOPY techniques to identify and quantify biological organisms and components with higher sensitivity and specificity than prior art techniques.
Annals of the New York Academy of Sciences, 1984
Blood, 1979
Many antibodies that cause paroxysmal cold hemoglobinuria (Donath-Landstelner antibodies) appear ... more Many antibodies that cause paroxysmal cold hemoglobinuria (Donath-Landstelner antibodies) appear to be directed against the blood group P antigen. We recently Identified this antigen as the glycosphingolipld globoside GaINAc(fl, 1-'3)Gal(a, 1-'4)Gal(fl, 1-'4)Glc-Cer, and we examined the reaction of four Donath-Landsteiner antibodies with anti-P specificity, and an anti-P acId autoagglutinin, with globoside and Forssman glycolipids. Forssman glycolipid, GaINAc(a, 1-3) GaINAc(fl, 1-'3)Gal(a, 1-'4)Gal(fi, 1-'4)GIc-Cer, contains the globoside structure plus an additional terminal nonreducing cr-GaINAc residue. All five antibodies were Inhibited effectively by globoside. Two of the Donath-Landstelner antibodies were InhIbited much more effectively by globoside than Forssman glycolipid, and the other two antibodies were inhibited more effectively by Forssman glycolipid. The two glycolipids were approximately equally effective in Inhibiting the acid anti-P agglutinln. We suggest that the populations of antibodies that react with both glycolipids are directed against an aspect of the globoside structure that is accessible in the Forssman compound, whereas the antibodies that react best with globoside are probably directed against the terminal fi-GaINAc residue of this glycolipid. Some human "anti-P" antibodies are probably elicited by immunization against Forssman antigens that are widespread In animal tissues and in microorganisms.
Immunology, 1997
Immunological responses, especially cytokines, play important roles in determining the persistenc... more Immunological responses, especially cytokines, play important roles in determining the persistence of infectious agents in chronic diseases. Thl responses enhance cellular immunity to control infection whereas Th2 immune responses down-regulate these effector immune responses. It has been suggested that the Thl to Th2 switch is involved in human immunodeficiency virus (HIV) disease progression. We studied the regulatory role of interleukin-4 (IL-4; Th2 response) on interferon-y (IFN-y; Thl response) in HIV infection and its role in the generation of HIV-specific cytotoxic T lymphocytes (CTL) in an in vitro system. Forty HIV-infected, asymptomatic individuals and 20 HIV-seronegative individuals were included in this study. Peripheral blood mononuclear cells were stimulated with phytohaemagglutinin and tetanus toxoid in the presence or absence of IL-4 to determine the effect of IL-4 on IFN-y production and HIV-Env-specific CTL activity. IL-4 showed a dual effect on IFN-y production in HIV patients. IL-4 down-regulated IFN-y production in HIV-seronegative individuals and in 55% of HIV patients whereas it stimulated IFN-y production in 45% of HIV patients. IL-4 increased HIV-Env-specific CTL activity in five of seven patients of the latter group. IL-4 has multiple biological activities, e.g. IL-4 inhibits IFNy production as well as stimulates CTL generation which in turn produces IFN-y. Understanding the biological significance of these interactions is of importance for immunotherapeutic approaches against HIV infection.
The Journal of Physical Chemistry, 1973
ABSTRACT
Proceedings of the National Academy of Sciences, 1976
Analytical Biochemistry, 1996
Coomassie brilliant blue R-250 (CBB) is a popular and widely used dye for detection of proteins b... more Coomassie brilliant blue R-250 (CBB) is a popular and widely used dye for detection of proteins by gel electrophoresis. However, commercially available CBBs are complex mixtures of numerous chromogenic compounds that vary from lot to lot, thereby giving an undesirable level of variation in reproducibility, precision, and specificity in staining gels. We have developed a silica gel column chromatographic method for purification of commercial CBBs in high yield and have standardized each lot to perform equivalently in staining proteins as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and quantitative scanning densitometry. This is a major improvement in protein purity determinations by quantitative scanning densitometry. A thinlayer chromatographic method for quality control testing of the purified CBB lots was also developed. Plasma desorption mass spectrometry was used to identify components of silica gel column fractions. Scanning densitometry was the technology used to establish performance equivalency between different CBB preparations. The less polar chromogenic compounds are nonblue and/or fluorescent in color, contain mono- or unsulfonated structures, and lack significant protein binding capacity. The more polar chromogenic compounds are green and blue-green in color, contain tri- and tetrasulfonated moieties, compared to the disulfonated structure of CBB, and bind to protein at least 40 times more effectively than pure CBB. The concentrations of these highly polar chromogens differ from lot to lot and act as "inhibitors" in protein staining, thereby causing variability in protein staining.
Journal of Lipid Research
Australian Journal of Chemistry
The Journal of Physical Chemistry, 1973
ABSTRACT
J Org Chem, 1969
or (3s)ja-androstane-3-spiro-2'-oxiran Acknowledgment We are indebted to the editors and publishe... more or (3s)ja-androstane-3-spiro-2'-oxiran Acknowledgment We are indebted to the editors and publishers (Elsevier Publishing Company) of BiochiFicu et Biophysicu Acta for permission to reproduce photographically the chemical structures that appeared in their publication of these tentative rules.
METHODS FOR DETECTING ORGANISMS AND ENZYMATIC REACTIONS USING RAMAN SPECTROSCOPY techniques to id... more METHODS FOR DETECTING ORGANISMS AND ENZYMATIC REACTIONS USING RAMAN SPECTROSCOPY techniques to identify and quantify biological organisms and components with higher sensitivity and specificity than prior art techniques.
Annals of the New York Academy of Sciences, 1984
Blood, 1979
Many antibodies that cause paroxysmal cold hemoglobinuria (Donath-Landstelner antibodies) appear ... more Many antibodies that cause paroxysmal cold hemoglobinuria (Donath-Landstelner antibodies) appear to be directed against the blood group P antigen. We recently Identified this antigen as the glycosphingolipld globoside GaINAc(fl, 1-'3)Gal(a, 1-'4)Gal(fl, 1-'4)Glc-Cer, and we examined the reaction of four Donath-Landsteiner antibodies with anti-P specificity, and an anti-P acId autoagglutinin, with globoside and Forssman glycolipids. Forssman glycolipid, GaINAc(a, 1-3) GaINAc(fl, 1-'3)Gal(a, 1-'4)Gal(fi, 1-'4)GIc-Cer, contains the globoside structure plus an additional terminal nonreducing cr-GaINAc residue. All five antibodies were Inhibited effectively by globoside. Two of the Donath-Landstelner antibodies were InhIbited much more effectively by globoside than Forssman glycolipid, and the other two antibodies were inhibited more effectively by Forssman glycolipid. The two glycolipids were approximately equally effective in Inhibiting the acid anti-P agglutinln. We suggest that the populations of antibodies that react with both glycolipids are directed against an aspect of the globoside structure that is accessible in the Forssman compound, whereas the antibodies that react best with globoside are probably directed against the terminal fi-GaINAc residue of this glycolipid. Some human "anti-P" antibodies are probably elicited by immunization against Forssman antigens that are widespread In animal tissues and in microorganisms.
Immunology, 1997
Immunological responses, especially cytokines, play important roles in determining the persistenc... more Immunological responses, especially cytokines, play important roles in determining the persistence of infectious agents in chronic diseases. Thl responses enhance cellular immunity to control infection whereas Th2 immune responses down-regulate these effector immune responses. It has been suggested that the Thl to Th2 switch is involved in human immunodeficiency virus (HIV) disease progression. We studied the regulatory role of interleukin-4 (IL-4; Th2 response) on interferon-y (IFN-y; Thl response) in HIV infection and its role in the generation of HIV-specific cytotoxic T lymphocytes (CTL) in an in vitro system. Forty HIV-infected, asymptomatic individuals and 20 HIV-seronegative individuals were included in this study. Peripheral blood mononuclear cells were stimulated with phytohaemagglutinin and tetanus toxoid in the presence or absence of IL-4 to determine the effect of IL-4 on IFN-y production and HIV-Env-specific CTL activity. IL-4 showed a dual effect on IFN-y production in HIV patients. IL-4 down-regulated IFN-y production in HIV-seronegative individuals and in 55% of HIV patients whereas it stimulated IFN-y production in 45% of HIV patients. IL-4 increased HIV-Env-specific CTL activity in five of seven patients of the latter group. IL-4 has multiple biological activities, e.g. IL-4 inhibits IFNy production as well as stimulates CTL generation which in turn produces IFN-y. Understanding the biological significance of these interactions is of importance for immunotherapeutic approaches against HIV infection.
The Journal of Physical Chemistry, 1973
ABSTRACT
Proceedings of the National Academy of Sciences, 1976
Analytical Biochemistry, 1996
Coomassie brilliant blue R-250 (CBB) is a popular and widely used dye for detection of proteins b... more Coomassie brilliant blue R-250 (CBB) is a popular and widely used dye for detection of proteins by gel electrophoresis. However, commercially available CBBs are complex mixtures of numerous chromogenic compounds that vary from lot to lot, thereby giving an undesirable level of variation in reproducibility, precision, and specificity in staining gels. We have developed a silica gel column chromatographic method for purification of commercial CBBs in high yield and have standardized each lot to perform equivalently in staining proteins as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and quantitative scanning densitometry. This is a major improvement in protein purity determinations by quantitative scanning densitometry. A thinlayer chromatographic method for quality control testing of the purified CBB lots was also developed. Plasma desorption mass spectrometry was used to identify components of silica gel column fractions. Scanning densitometry was the technology used to establish performance equivalency between different CBB preparations. The less polar chromogenic compounds are nonblue and/or fluorescent in color, contain mono- or unsulfonated structures, and lack significant protein binding capacity. The more polar chromogenic compounds are green and blue-green in color, contain tri- and tetrasulfonated moieties, compared to the disulfonated structure of CBB, and bind to protein at least 40 times more effectively than pure CBB. The concentrations of these highly polar chromogens differ from lot to lot and act as "inhibitors" in protein staining, thereby causing variability in protein staining.
Journal of Lipid Research
Australian Journal of Chemistry
The Journal of Physical Chemistry, 1973
ABSTRACT
J Org Chem, 1969
or (3s)ja-androstane-3-spiro-2'-oxiran Acknowledgment We are indebted to the editors and publishe... more or (3s)ja-androstane-3-spiro-2'-oxiran Acknowledgment We are indebted to the editors and publishers (Elsevier Publishing Company) of BiochiFicu et Biophysicu Acta for permission to reproduce photographically the chemical structures that appeared in their publication of these tentative rules.