Sanford Markey | National Institutes of Health (original) (raw)

Papers by Sanford Markey

IDO induction can deplete L-tryptophan in target cells, an effect partially responsible for the a... more IDO induction can deplete L-tryptophan in target cells, an effect partially responsible for the antimicrobial activities and antial- logeneic T cell responses of IFN- in human macrophages, dendritic cells, and bone marrow cells. L-Tryptophan depletion and NO production are both known to have an antimicrobial effect in macrophages, and the interaction of these two mechanisms is unclear. In this study

Neuroscience, 1991

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) selectively destroys dopaminergic neurons of ... more 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) selectively destroys dopaminergic neurons of the substantia nigra pars compacta in humans and other primates, producing a parkinsonian condition. MPTP is metabolized to the toxin 1-methyl-4-phenylpyridine (MPP+) which is taken up by dopamine terminals. The subsequent events culminating in cell death in the substantia nigra pars compacta are not understood. To examine these events we first produced a chronic hemiparkinsonian condition in monkeys by administering a toxic dose of MPTP via the right carotid artery. One year later, these monkeys were given a trace dose of [14C]MPTP intravenously and allowed to survive 1, 3, or 10 days. In two acute conditions, monkeys were either given the radiolabeled trace dose intravenously immediately following the toxic intracarotid dose, or were given a single toxic intracarotid radiolabeled dose, and allowed to survive 1, 3, or 10 days. We show by histology and autoradiography that the chronic he...

This study investigated the sources of quinolinic acid, a neurotoxic tryptophan-kynurenine pathwa... more This study investigated the sources of quinolinic acid, a neurotoxic tryptophan-kynurenine pathway metabolite, in the brain and blood of HIV- infected patients and retrovirus-infected macaques. In brain, quinolinic acid concentrations in HIV-infected patients were elevated byú300-fold to concentrations that exceeded cerebrospinal fluid (CSF) by 8.9-fold. There were no significant correlations between ele- vated serum quinolinic acid levels with those in

We have used cultured ventral mesencephalic and cere- bellar granule cells to test the toxicity o... more We have used cultured ventral mesencephalic and cere- bellar granule cells to test the toxicity of extracts of cycad seeds (genus Cycas) and cycad-derived flours traditionally prepared in Guam. There was no significant difference in the toxicity of extracts prepared from the female gameto- phyte tissue of C. circinalis, C, revoluta, and C. media, com- mon wheat flour, and 13

Journal of Chromatography A, 2005

A one- or two-dimensional high performance liquid chromatography system for electrospray ionizati... more A one- or two-dimensional high performance liquid chromatography system for electrospray ionization mass spectrometers has been developed that is optimized for ion exchange and reversed phase separations. A unique and simple valve configuration permits the use of a variety of non-volatile salts; ammonium sulfate was used in an example of strong cation exchange separations. The system was designed and evaluated

Journal of Proteome Research, 2005

An algorithm is introduced to assess spectral quality for peptide CID spectra acquired by a quadr... more An algorithm is introduced to assess spectral quality for peptide CID spectra acquired by a quadrupole ion trap mass spectrometer. The method employs a quadratic discriminant function calibrated with manually classified 'bad' and 'good' quality spectra, producing a single 'spectral quality' score. Many spectra examined that do not have significant matches are assessed to have good spectral quality, indicating that advances in search methods may yield substantial improvements in results.

Psychiatry Research, 1979

Proceedings of the National Academy of Sciences, 2008

Molecular & Cellular Proteomics, 2007

Postsynaptic density protein 95 (PSD-95), a specialized scaffold protein with multiple protein in... more Postsynaptic density protein 95 (PSD-95), a specialized scaffold protein with multiple protein interaction domains, forms the backbone of an extensive postsynaptic protein complex that organizes receptors and signal transduction molecules at the synaptic contact zone. Large, detergent-insoluble PSD-95-based postsynaptic complexes can be affinity-purified from conventional PSD fractions using magnetic beads coated with a PSD-95 antibody. In the present study purified PSD-95 complexes were analyzed by LC/MS/MS. A semiquantitative measure of the relative abundances of proteins in the purified PSD-95 complexes and the parent PSD fraction was estimated based on the cumulative ion current intensities of corresponding peptides. The affinity-purified preparation was largely depleted of presynaptic proteins, spectrin, intermediate filaments, and other contaminants prominent in the parent PSD fraction. We identified 525 of the proteins previously reported in parent PSD fractions, but only 288 of these were detected after affinity purification. We discuss 26 proteins that are major components in the PSD-95 complex based upon abundance ranking and affinity co-purification with PSD-95. This subset represents a minimal list of constituent proteins of the PSD-95 complex and includes, in addition to the specialized scaffolds and N-methyl-d-aspartate (NMDA) receptors, an abundance of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, small G-protein regulators, cell adhesion molecules, and hypothetical proteins. The identification of two Arf regulators, BRAG1 and BRAG2b, as co-purifying components of the complex implies pivotal functions in spine plasticity such as the reorganization of the actin cytoskeleton and insertion and retrieval of proteins to and from the plasma membrane. Another co-purifying protein (Q8BZM2) with two sterile alpha motif domains may represent a novel structural core element of the PSD.

Life Sciences, 1986

MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) produces an irreversible parkinsonism in prim... more MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) produces an irreversible parkinsonism in primates. Recent evidence suggests metabolism of MPTP to 1-methyl-4-phenylpyridine (MPP+) is required for toxicity. We have proposed that MPP+ may play a central role in the toxicity of MPTP, but direct assessment of the effects of MPP+ in brain is difficult. Therefore, we have sought to define the mechanism of peripheral MPP+ toxicity in the rat and mouse. Systemically administered MPP+ produced its major pathology in the lung and was typified by perivascular edema. An increase in plasma glutathione disulfide concentrations also resulted, suggesting that MPP+ in analogy to paraquat produces oxidative stress. In addition, the lethality of MPP+ in the mouse was increased by dietary selenium deficiency. These results define in both pathological and chemical terms the potent systemic toxicity of MPP+ and suggest that MPP+, because of its high concentration in primate brain, has the potential to play an important role in the CNS toxicity of MPTP.

Journal of Proteome Research, 2004

Journal of Proteome Research, 2004

Journal of Pharmaceutical Sciences, 1986

Journal of Pharmaceutical Sciences, 1986

Journal of Neuroscience Research, 2005

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI MS) can detec... more Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI MS) can detect substantial changes in expression of proteins in tissues, such as cancer cells. A more challenging problem is detecting the smaller changes expected in normal development or complex diseases. Here we address methodological issues regarding the acquisition and analysis of MALDI MS data from tissue sections, in a study of mouse cerebellum at different stages of development. Sections of the cerebellar cortex were analyzed at the peak of granule neuron production [postnatal day (P) 7], during synapse formation (P14), and in adults. Data were acquired (Voyager-DEtrade mark STR Biospectrometry Workstation; seven acquisitions of 50 shots per section, 3.5-50 kDa), preprocessed (Data Explorer 4.3), and averaged. Among 846 peaks detected, in at least 50% of at least one group, 122 showed significant group differences (Kruskal-Wallis ANOVA) after Bonferroni correction. Factor analyses revealed two age-related factors, possibly reflecting gradients of expression during development. Predictive analysis of microarrays generated a model from half of the sample that correctly predicted developmental groups for the second half. Intraclass correlation coefficients, measuring within-mouse consistency of peak heights from three tissue sections, were acceptable at lower m/z and for larger peaks at higher m/z. Low mass was the best predictor of significant group differences. The analysis demonstrates that MALDI MS of normal tissue sections at different ages can detect consistent, significant group differences. Further work is needed to increase the sensitivity of the methods and to apply them reliably to brain regions and to subproteomes with relevance to diverse brain functions and diseases.

Journal of Neuroimmunology, 1992

Journal of Neurochemistry, 1989

IDO induction can deplete L-tryptophan in target cells, an effect partially responsible for the a... more IDO induction can deplete L-tryptophan in target cells, an effect partially responsible for the antimicrobial activities and antial- logeneic T cell responses of IFN- in human macrophages, dendritic cells, and bone marrow cells. L-Tryptophan depletion and NO production are both known to have an antimicrobial effect in macrophages, and the interaction of these two mechanisms is unclear. In this study

Neuroscience, 1991

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) selectively destroys dopaminergic neurons of ... more 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) selectively destroys dopaminergic neurons of the substantia nigra pars compacta in humans and other primates, producing a parkinsonian condition. MPTP is metabolized to the toxin 1-methyl-4-phenylpyridine (MPP+) which is taken up by dopamine terminals. The subsequent events culminating in cell death in the substantia nigra pars compacta are not understood. To examine these events we first produced a chronic hemiparkinsonian condition in monkeys by administering a toxic dose of MPTP via the right carotid artery. One year later, these monkeys were given a trace dose of [14C]MPTP intravenously and allowed to survive 1, 3, or 10 days. In two acute conditions, monkeys were either given the radiolabeled trace dose intravenously immediately following the toxic intracarotid dose, or were given a single toxic intracarotid radiolabeled dose, and allowed to survive 1, 3, or 10 days. We show by histology and autoradiography that the chronic he...

This study investigated the sources of quinolinic acid, a neurotoxic tryptophan-kynurenine pathwa... more This study investigated the sources of quinolinic acid, a neurotoxic tryptophan-kynurenine pathway metabolite, in the brain and blood of HIV- infected patients and retrovirus-infected macaques. In brain, quinolinic acid concentrations in HIV-infected patients were elevated byú300-fold to concentrations that exceeded cerebrospinal fluid (CSF) by 8.9-fold. There were no significant correlations between ele- vated serum quinolinic acid levels with those in

We have used cultured ventral mesencephalic and cere- bellar granule cells to test the toxicity o... more We have used cultured ventral mesencephalic and cere- bellar granule cells to test the toxicity of extracts of cycad seeds (genus Cycas) and cycad-derived flours traditionally prepared in Guam. There was no significant difference in the toxicity of extracts prepared from the female gameto- phyte tissue of C. circinalis, C, revoluta, and C. media, com- mon wheat flour, and 13

Journal of Chromatography A, 2005

A one- or two-dimensional high performance liquid chromatography system for electrospray ionizati... more A one- or two-dimensional high performance liquid chromatography system for electrospray ionization mass spectrometers has been developed that is optimized for ion exchange and reversed phase separations. A unique and simple valve configuration permits the use of a variety of non-volatile salts; ammonium sulfate was used in an example of strong cation exchange separations. The system was designed and evaluated

Journal of Proteome Research, 2005

An algorithm is introduced to assess spectral quality for peptide CID spectra acquired by a quadr... more An algorithm is introduced to assess spectral quality for peptide CID spectra acquired by a quadrupole ion trap mass spectrometer. The method employs a quadratic discriminant function calibrated with manually classified 'bad' and 'good' quality spectra, producing a single 'spectral quality' score. Many spectra examined that do not have significant matches are assessed to have good spectral quality, indicating that advances in search methods may yield substantial improvements in results.

Psychiatry Research, 1979

Proceedings of the National Academy of Sciences, 2008

Molecular & Cellular Proteomics, 2007

Postsynaptic density protein 95 (PSD-95), a specialized scaffold protein with multiple protein in... more Postsynaptic density protein 95 (PSD-95), a specialized scaffold protein with multiple protein interaction domains, forms the backbone of an extensive postsynaptic protein complex that organizes receptors and signal transduction molecules at the synaptic contact zone. Large, detergent-insoluble PSD-95-based postsynaptic complexes can be affinity-purified from conventional PSD fractions using magnetic beads coated with a PSD-95 antibody. In the present study purified PSD-95 complexes were analyzed by LC/MS/MS. A semiquantitative measure of the relative abundances of proteins in the purified PSD-95 complexes and the parent PSD fraction was estimated based on the cumulative ion current intensities of corresponding peptides. The affinity-purified preparation was largely depleted of presynaptic proteins, spectrin, intermediate filaments, and other contaminants prominent in the parent PSD fraction. We identified 525 of the proteins previously reported in parent PSD fractions, but only 288 of these were detected after affinity purification. We discuss 26 proteins that are major components in the PSD-95 complex based upon abundance ranking and affinity co-purification with PSD-95. This subset represents a minimal list of constituent proteins of the PSD-95 complex and includes, in addition to the specialized scaffolds and N-methyl-d-aspartate (NMDA) receptors, an abundance of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, small G-protein regulators, cell adhesion molecules, and hypothetical proteins. The identification of two Arf regulators, BRAG1 and BRAG2b, as co-purifying components of the complex implies pivotal functions in spine plasticity such as the reorganization of the actin cytoskeleton and insertion and retrieval of proteins to and from the plasma membrane. Another co-purifying protein (Q8BZM2) with two sterile alpha motif domains may represent a novel structural core element of the PSD.

Life Sciences, 1986

MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) produces an irreversible parkinsonism in prim... more MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) produces an irreversible parkinsonism in primates. Recent evidence suggests metabolism of MPTP to 1-methyl-4-phenylpyridine (MPP+) is required for toxicity. We have proposed that MPP+ may play a central role in the toxicity of MPTP, but direct assessment of the effects of MPP+ in brain is difficult. Therefore, we have sought to define the mechanism of peripheral MPP+ toxicity in the rat and mouse. Systemically administered MPP+ produced its major pathology in the lung and was typified by perivascular edema. An increase in plasma glutathione disulfide concentrations also resulted, suggesting that MPP+ in analogy to paraquat produces oxidative stress. In addition, the lethality of MPP+ in the mouse was increased by dietary selenium deficiency. These results define in both pathological and chemical terms the potent systemic toxicity of MPP+ and suggest that MPP+, because of its high concentration in primate brain, has the potential to play an important role in the CNS toxicity of MPTP.

Journal of Proteome Research, 2004

Journal of Proteome Research, 2004

Journal of Pharmaceutical Sciences, 1986

Journal of Pharmaceutical Sciences, 1986

Journal of Neuroscience Research, 2005

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI MS) can detec... more Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI MS) can detect substantial changes in expression of proteins in tissues, such as cancer cells. A more challenging problem is detecting the smaller changes expected in normal development or complex diseases. Here we address methodological issues regarding the acquisition and analysis of MALDI MS data from tissue sections, in a study of mouse cerebellum at different stages of development. Sections of the cerebellar cortex were analyzed at the peak of granule neuron production [postnatal day (P) 7], during synapse formation (P14), and in adults. Data were acquired (Voyager-DEtrade mark STR Biospectrometry Workstation; seven acquisitions of 50 shots per section, 3.5-50 kDa), preprocessed (Data Explorer 4.3), and averaged. Among 846 peaks detected, in at least 50% of at least one group, 122 showed significant group differences (Kruskal-Wallis ANOVA) after Bonferroni correction. Factor analyses revealed two age-related factors, possibly reflecting gradients of expression during development. Predictive analysis of microarrays generated a model from half of the sample that correctly predicted developmental groups for the second half. Intraclass correlation coefficients, measuring within-mouse consistency of peak heights from three tissue sections, were acceptable at lower m/z and for larger peaks at higher m/z. Low mass was the best predictor of significant group differences. The analysis demonstrates that MALDI MS of normal tissue sections at different ages can detect consistent, significant group differences. Further work is needed to increase the sensitivity of the methods and to apply them reliably to brain regions and to subproteomes with relevance to diverse brain functions and diseases.

Journal of Neuroimmunology, 1992

Journal of Neurochemistry, 1989