Daniel Boismenu - Academia.edu (original) (raw)

Papers by Daniel Boismenu

International journal of pharmaceutical compounding

The purpose of this study was to determine the room temperature stability over a period of severa... more The purpose of this study was to determine the room temperature stability over a period of several months of commercially available intravenous succinylcholine dichloride (Quelicin, 20 mg/mL) in vials. A previously validated electro-spray tandem mass spectrometry method developed for the determination of succinylcholine dichloride in plasma was used. This method was based upon a stable isotope dilution assay using hexadeuterosuccinylcholine diiodide as the internal standard and was shown to be specific, sensitive, and reproducible. Calibration curves were plots of the ratios of intensities of the major product ions in the collision-induced dissociation spectrum for known concentration ratios of succinylcholine dichloride and hexadeuterosuccinylcholine diiodide in solutions. The concentration of succinylcholine dichloride was shown to decline linearly. After 1, 3, and 6 months at room temperature, the vial contents retained approximately 98%, 95%, and 90% of their inital concentratio...

PROTEOMICS - CLINICAL APPLICATIONS, 2009

To date the cellular and molecular mechanisms by which liver pathological calcifications occur an... more To date the cellular and molecular mechanisms by which liver pathological calcifications occur and are regulated are poorly investigated. To study the mechanisms linked to their appearance, we performed a proteomics analysis of calcified liver samples. To this end, human liver biopsies collected in noncalcified (N), precalcified (P), and calcified (C) areas of the liver were subjected to weak ion exchange chromatography, SDS-PAGE, and LC-ESI MS/MS analyses. As we previously demonstrated that alpha-smooth muscle actin (α-SMA) expressing myofibroblasts were involved in liver pathological calcification, we performed a targeted analysis of actin cytoskeleton remodeling-related proteins. This revealed dramatic changes in protein expression patterns in the periphery of the calcified areas. More particularly, we found that IQGAP1 and IQGAP2 proteins were subjected to major expression changes. We show that IQGAP1 expression within P and C areas of the liver correlates with the high abundance of myofibroblasts and that IQGAP1 is specifically expressed in these cells. In addition, we find that IQGAP1 is part of a protein complex including β-catenin and Rac1 mainly in P and C regions of the liver. These results suggest that IQGAP1 may play a critical role in the regulation of cytoskeleton remodeling in liver myofibroblasts in response to liver injury and consequently impact on their function.

Special publication, Mar 26, 2007

Molecular & Cellular Proteomics, 2003

Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439), 2003

Abstract Summary form only given. Proteomics, focuses on the identification, localization, and fu... more Abstract Summary form only given. Proteomics, focuses on the identification, localization, and functional analysis of the protein make up of the cell. It evolved from genomics, where the focus is on the information of one target molecule DNA. Genomics involves the high ...

The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

Current peak detections algorithms for processing mass spectrometry (MS) spectra generally rely o... more Current peak detections algorithms for processing mass spectrometry (MS) spectra generally rely on two dimensional techniques for identifying the location and intensity of peaks from a single spectrum. However, when high performance liquid chromatography (HPLC) is coupled with mass spectrometry, a third dimension, retention time, is introduced. The ensemble of MS spectra may then be regarded as a 3D surface where spectral intensity is a function of m/z (mass-to-charge) and time. This suggests that peak localization can be improved by incorporating the time domain data and average data across both dimensions. This work describes a surface intensity analysis algorithm and the results of its use.

Enthoprotin: a novel clathrin-associated protein identified through subcellular proteomics Sylwia... more Enthoprotin: a novel clathrin-associated protein identified through subcellular proteomics Sylwia Wasiak,

Human cells contain more than 60 Ras-like, Rab GTPases that are localized to the surfaces of dist... more Human cells contain more than 60 Ras-like, Rab GTPases that are localized to the surfaces of distinct membrane-bound compartments. Rabs are master regulators of membrane traffic events: they can catalyze the formation of membrane microdomains, the collection of cargo into transport vesicles, the motility of vesicles along cytoskeletal tracks, the docking of vesicles with their targets, and the subsequent membrane fusion process. Rab protein function has broad implication for our understanding of human disease. For example, mutations in Rab27 lead to Griscelli syndrome due to defects in melanosome transport in melanocytes and loss of cytotoxic killing activity in T cells. Other genetic diseases are caused by loss of function of multiple Rab proteins due to mutations in common Rab regulators. My laboratory studies the Rab9 GTPase that is essential for transport of mannose 6-phosphate receptors between late endosomes and the Golgi complex. Rab9 forms a distinct domain in late endosome ...

Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439), 2003

'Montreal Proteomics Network, Montreal, QC, Canada, 'Department of Biomedical Engineeri... more 'Montreal Proteomics Network, Montreal, QC, Canada, 'Department of Biomedical Engineering, McGill University, Montreal, QC, Canada, 'Dept. of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada ... Abstract-Information systems supporting the protein ...

The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

In high-throughput proteomics, a promising approach presently being explored is the use of liquid... more In high-throughput proteomics, a promising approach presently being explored is the use of liquid chromatography coupled to Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR-MS) to provide measurements of the masses of tryptic peptides in complex mixtures, which can then be used to identify the proteins which gave rise to those peptides. In order to apply this method, it is necessary to account for any systematic measurement error, and it is useful to have an estimate of the random error in measured masses. In this investigation, a complex mixture of peptides derived from a partially characterized sample was analyzed by LC-FTICR-MS. Through the application of a Bayesian probability model of the data, partial knowledge of the composition of the sample is sufficient both to determine any systematic error and to estimate the random error in measured masses.

Journal of Food Science, 1991

ABSTRACTSpoilage bacteria of cod fillets were desorbed off the fillet surface by ultrasonication.... more ABSTRACTSpoilage bacteria of cod fillets were desorbed off the fillet surface by ultrasonication. Catalase activity of these bacteria was determined using the disc flotation method after selective heat inactivation of the endogenous cod catalase and then correlated with the colony forming units. The method was applied to cod fillets from ten retail sources with satisfactory results.

Journal of Food Science, 1990

ABSTRACTCatalase from Pseudomonas sp. and Micrococcus sp. bacteria is inactivated at 93°C and 73°... more ABSTRACTCatalase from Pseudomonas sp. and Micrococcus sp. bacteria is inactivated at 93°C and 73°C, respectively, while cod muscle catalase is inactivated at 41°C. This implies that a suitable thermal treatment of a mixture of cod muscle and bacterial catalases will destroy only the cod catalase and leave the bacterial catalase unaltered. The activity of the remaining bacterial catalase is then measured using the disc flotation method.

Molecular and cellular biology, 2008

When endoplasmic reticulum (ER) homeostasis is perturbed, an adaptive mechanism is triggered and ... more When endoplasmic reticulum (ER) homeostasis is perturbed, an adaptive mechanism is triggered and named the unfolded protein response (UPR). Thus far, three known UPR signaling branches (IRE-1, PERK, and ATF-6) mediate the reestablishment of ER functions but can also lead to apoptosis if ER stress is not alleviated. However, the understanding of the molecular mechanisms integrating the UPR to other ER functions, such as membrane traffic or endomembrane signaling, remains incomplete. We consequently sought to identify new regulators of UPR-dependent transcriptional mechanisms and focused on a family of proteins known to mediate, among other, ER-related functions: the small GTP-binding proteins of the RAS superfamily. To this end, we used transgenic UPR reporter Caenorhabditis elegans strains as a model to specifically silence small-GTPase expression. We show that the Rho subfamily member CRP-1 is an essential component of UPR-induced transcriptional events through its physical and gen...

Journal of Membrane Biology, 2000

Porin of Haemophilus influenzae type b (341 amino acids; M r 37782) determines the permeability o... more Porin of Haemophilus influenzae type b (341 amino acids; M r 37782) determines the permeability of the outer membrane to low molecular mass compounds. Purified Hib porin was subjected to chemical modification of lysine residues by succinic anhydride. Electrospray ionization mass spectrometry identified up to 12 modifications per porin molecule. Tryptic digestion of modified Hib porin followed by reverse phase chromatography and matrix assisted laser desorption ionization time-of-flight mass spectrometry mapped the succinylation sites. Most modified lysines are positioned in surface-located loops, numbers 1 and 4 to 7. Succinylated porin was reconstituted into planar lipid bilayers, and biophysical properties were analyzed and compared to Hib porin: there was an increased average single channel conductance compared to Hib porin (1.24+/−0.41 vs. 0.85+/−0.40 nanosiemens). The voltage-gating activity of succinylated porin differed considerably from that of Hib porin. The threshold voltage for gating was decreased from 75 to 40 mV. At 80 mV, steady-state conductance for succinylated porin was 50-55% of the instantaneous conductance. Hib porin at 80 mV showed a decrease to 89-91% of the instantaneous current levels. We propose that surface-located lysine residues are determinants of voltage gating for porin of Haemophilus influenzae type b.

Proceedings of the National Academy of Sciences, 2004

Tandem MS has identified 209 proteins of clathrin-coated vesicles (CCVs) isolated from rat brain.... more Tandem MS has identified 209 proteins of clathrin-coated vesicles (CCVs) isolated from rat brain. An overwhelming abundance of peptides were assigned to the clathrin coat with a 1:1 stoichiometry observed for clathrin heavy and light chains and a 2:1 stoichiometry of clathrin heavy chain with clathrin adaptor protein heterotetramers. Thirty-two proteins representing many of the known components of synaptic vesicles (SVs) were identified, supporting that a main function for brain CCVs is to recapture SVs after exocytosis. A ratio of vesicle- N -ethylmaleimide-sensitive factor attachment protein receptors to target- N -ethylmaleimide-sensitive factor attachment protein receptors, similar to that previously detected on SVs, supports a single-step model for SV sorting during CCV-mediated recycling of SVs. The uncovering of eight previously undescribed proteins, four of which have to date been linked to clathrin-mediated trafficking, further attests to the value of the current organelle-...

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 1999

Liquid chromatography/mass spectrometry using electrospray ionisation was used to analyse rhamnol... more Liquid chromatography/mass spectrometry using electrospray ionisation was used to analyse rhamnolipids produced by a Pseudomonas aeruginosa strain with mannitol or naphthalene as carbon source. Identification and quantification of 28 different rhamnolipid congeners was accomplished using a reverse-phase C18 column and a 30 min chromatographic run. Isomeric rhamnolipids that were not chromatographically resolved could be identified by interpretation of their mass

Molecular & Cellular Proteomics, 2006

Immunogenetics, 2002

The B6 dom1 minor histocompatibility antigen (MiHA) is a model antigen, since it is both the epit... more The B6 dom1 minor histocompatibility antigen (MiHA) is a model antigen, since it is both the epitome of an immunodominant epitope and an ideal target for adoptive cancer immunotherapy. Based on DNA sequencing and MS/MS analyses, we report that B6 dom1 corresponds to amino acids 770-778 (KAPDNRETL) of a protein we propose to call SIMP (source of immunodominant MHC-associated peptides) that is encoded by a mouse homolog of the yeast STT3 gene. STT3, a member of the oligosaccharyltransferase complex, is essential for cell proliferation. Phenotypic and genotypic analyses among eight strains of mice revealed a precise correlation between susceptibility or resistance to B6 dom1-specific cytotoxic T lymphocytes (CTLs) and the presence of a Glu vs Asp amino acid at position 776 of the SIMP protein, respectively. Strikingly, while the difference in the amino acid sequence 770-778 encoded by the two SIMP alleles represents a very conservative substitution, these allelic peptides were not crossreactive at the CTL level, and both peptides were immunodominant when presented to mice homozygous for the opposite allele. In addition, we have cloned a human ortholog of SIMP whose predicted protein shares 97% amino acid identity with mouse SIMP. These results strengthen the concept that MHC class-I-associated MiHAs originate as a consequence of rare polymorphisms among highly conserved genes. Furthermore, the notion that a peptide differing from a self analog by a single methylene group can be immunodominant has implications regarding our understanding of the mechanisms of immunodominance.

International Journal of Pharmaceutical Compounding

The purpose of this study was to determine the room temperature stability over a period of severa... more The purpose of this study was to determine the room temperature stability over a period of several months of commercially available intravenous succinylcholine dichloride (Quelicin, 20 mg/mL) in vials. A previously validated electro-spray tandem mass spectrometry method developed for the determination of succinylcholine dichloride in plasma was used. This method was based upon a stable isotope dilution assay using hexadeuterosuccinylcholine diiodide as the internal standard and was shown to be specific, sensitive, and reproducible. Calibration curves were plots of the ratios of intensities of the major product ions in the collision-induced dissociation spectrum for known concentration ratios of succinylcholine dichloride and hexadeuterosuccinylcholine diiodide in solutions. The concentration of succinylcholine dichloride was shown to decline linearly. After 1, 3, and 6 months at room temperature, the vial contents retained approximately 98%, 95%, and 90% of their inital concentration, respectively. We suggest, therefore, that succinylcholine dichloride can be stored safely at room temperature under normal daylight for 6 months.

International journal of pharmaceutical compounding

The purpose of this study was to determine the room temperature stability over a period of severa... more The purpose of this study was to determine the room temperature stability over a period of several months of commercially available intravenous succinylcholine dichloride (Quelicin, 20 mg/mL) in vials. A previously validated electro-spray tandem mass spectrometry method developed for the determination of succinylcholine dichloride in plasma was used. This method was based upon a stable isotope dilution assay using hexadeuterosuccinylcholine diiodide as the internal standard and was shown to be specific, sensitive, and reproducible. Calibration curves were plots of the ratios of intensities of the major product ions in the collision-induced dissociation spectrum for known concentration ratios of succinylcholine dichloride and hexadeuterosuccinylcholine diiodide in solutions. The concentration of succinylcholine dichloride was shown to decline linearly. After 1, 3, and 6 months at room temperature, the vial contents retained approximately 98%, 95%, and 90% of their inital concentratio...

PROTEOMICS - CLINICAL APPLICATIONS, 2009

To date the cellular and molecular mechanisms by which liver pathological calcifications occur an... more To date the cellular and molecular mechanisms by which liver pathological calcifications occur and are regulated are poorly investigated. To study the mechanisms linked to their appearance, we performed a proteomics analysis of calcified liver samples. To this end, human liver biopsies collected in noncalcified (N), precalcified (P), and calcified (C) areas of the liver were subjected to weak ion exchange chromatography, SDS-PAGE, and LC-ESI MS/MS analyses. As we previously demonstrated that alpha-smooth muscle actin (α-SMA) expressing myofibroblasts were involved in liver pathological calcification, we performed a targeted analysis of actin cytoskeleton remodeling-related proteins. This revealed dramatic changes in protein expression patterns in the periphery of the calcified areas. More particularly, we found that IQGAP1 and IQGAP2 proteins were subjected to major expression changes. We show that IQGAP1 expression within P and C areas of the liver correlates with the high abundance of myofibroblasts and that IQGAP1 is specifically expressed in these cells. In addition, we find that IQGAP1 is part of a protein complex including β-catenin and Rac1 mainly in P and C regions of the liver. These results suggest that IQGAP1 may play a critical role in the regulation of cytoskeleton remodeling in liver myofibroblasts in response to liver injury and consequently impact on their function.

Special publication, Mar 26, 2007

Molecular & Cellular Proteomics, 2003

Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439), 2003

Abstract Summary form only given. Proteomics, focuses on the identification, localization, and fu... more Abstract Summary form only given. Proteomics, focuses on the identification, localization, and functional analysis of the protein make up of the cell. It evolved from genomics, where the focus is on the information of one target molecule DNA. Genomics involves the high ...

The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

Current peak detections algorithms for processing mass spectrometry (MS) spectra generally rely o... more Current peak detections algorithms for processing mass spectrometry (MS) spectra generally rely on two dimensional techniques for identifying the location and intensity of peaks from a single spectrum. However, when high performance liquid chromatography (HPLC) is coupled with mass spectrometry, a third dimension, retention time, is introduced. The ensemble of MS spectra may then be regarded as a 3D surface where spectral intensity is a function of m/z (mass-to-charge) and time. This suggests that peak localization can be improved by incorporating the time domain data and average data across both dimensions. This work describes a surface intensity analysis algorithm and the results of its use.

Enthoprotin: a novel clathrin-associated protein identified through subcellular proteomics Sylwia... more Enthoprotin: a novel clathrin-associated protein identified through subcellular proteomics Sylwia Wasiak,

Human cells contain more than 60 Ras-like, Rab GTPases that are localized to the surfaces of dist... more Human cells contain more than 60 Ras-like, Rab GTPases that are localized to the surfaces of distinct membrane-bound compartments. Rabs are master regulators of membrane traffic events: they can catalyze the formation of membrane microdomains, the collection of cargo into transport vesicles, the motility of vesicles along cytoskeletal tracks, the docking of vesicles with their targets, and the subsequent membrane fusion process. Rab protein function has broad implication for our understanding of human disease. For example, mutations in Rab27 lead to Griscelli syndrome due to defects in melanosome transport in melanocytes and loss of cytotoxic killing activity in T cells. Other genetic diseases are caused by loss of function of multiple Rab proteins due to mutations in common Rab regulators. My laboratory studies the Rab9 GTPase that is essential for transport of mannose 6-phosphate receptors between late endosomes and the Golgi complex. Rab9 forms a distinct domain in late endosome ...

Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439), 2003

'Montreal Proteomics Network, Montreal, QC, Canada, 'Department of Biomedical Engineeri... more 'Montreal Proteomics Network, Montreal, QC, Canada, 'Department of Biomedical Engineering, McGill University, Montreal, QC, Canada, 'Dept. of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada ... Abstract-Information systems supporting the protein ...

The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

In high-throughput proteomics, a promising approach presently being explored is the use of liquid... more In high-throughput proteomics, a promising approach presently being explored is the use of liquid chromatography coupled to Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR-MS) to provide measurements of the masses of tryptic peptides in complex mixtures, which can then be used to identify the proteins which gave rise to those peptides. In order to apply this method, it is necessary to account for any systematic measurement error, and it is useful to have an estimate of the random error in measured masses. In this investigation, a complex mixture of peptides derived from a partially characterized sample was analyzed by LC-FTICR-MS. Through the application of a Bayesian probability model of the data, partial knowledge of the composition of the sample is sufficient both to determine any systematic error and to estimate the random error in measured masses.

Journal of Food Science, 1991

ABSTRACTSpoilage bacteria of cod fillets were desorbed off the fillet surface by ultrasonication.... more ABSTRACTSpoilage bacteria of cod fillets were desorbed off the fillet surface by ultrasonication. Catalase activity of these bacteria was determined using the disc flotation method after selective heat inactivation of the endogenous cod catalase and then correlated with the colony forming units. The method was applied to cod fillets from ten retail sources with satisfactory results.

Journal of Food Science, 1990

ABSTRACTCatalase from Pseudomonas sp. and Micrococcus sp. bacteria is inactivated at 93°C and 73°... more ABSTRACTCatalase from Pseudomonas sp. and Micrococcus sp. bacteria is inactivated at 93°C and 73°C, respectively, while cod muscle catalase is inactivated at 41°C. This implies that a suitable thermal treatment of a mixture of cod muscle and bacterial catalases will destroy only the cod catalase and leave the bacterial catalase unaltered. The activity of the remaining bacterial catalase is then measured using the disc flotation method.

Molecular and cellular biology, 2008

When endoplasmic reticulum (ER) homeostasis is perturbed, an adaptive mechanism is triggered and ... more When endoplasmic reticulum (ER) homeostasis is perturbed, an adaptive mechanism is triggered and named the unfolded protein response (UPR). Thus far, three known UPR signaling branches (IRE-1, PERK, and ATF-6) mediate the reestablishment of ER functions but can also lead to apoptosis if ER stress is not alleviated. However, the understanding of the molecular mechanisms integrating the UPR to other ER functions, such as membrane traffic or endomembrane signaling, remains incomplete. We consequently sought to identify new regulators of UPR-dependent transcriptional mechanisms and focused on a family of proteins known to mediate, among other, ER-related functions: the small GTP-binding proteins of the RAS superfamily. To this end, we used transgenic UPR reporter Caenorhabditis elegans strains as a model to specifically silence small-GTPase expression. We show that the Rho subfamily member CRP-1 is an essential component of UPR-induced transcriptional events through its physical and gen...

Journal of Membrane Biology, 2000

Porin of Haemophilus influenzae type b (341 amino acids; M r 37782) determines the permeability o... more Porin of Haemophilus influenzae type b (341 amino acids; M r 37782) determines the permeability of the outer membrane to low molecular mass compounds. Purified Hib porin was subjected to chemical modification of lysine residues by succinic anhydride. Electrospray ionization mass spectrometry identified up to 12 modifications per porin molecule. Tryptic digestion of modified Hib porin followed by reverse phase chromatography and matrix assisted laser desorption ionization time-of-flight mass spectrometry mapped the succinylation sites. Most modified lysines are positioned in surface-located loops, numbers 1 and 4 to 7. Succinylated porin was reconstituted into planar lipid bilayers, and biophysical properties were analyzed and compared to Hib porin: there was an increased average single channel conductance compared to Hib porin (1.24+/−0.41 vs. 0.85+/−0.40 nanosiemens). The voltage-gating activity of succinylated porin differed considerably from that of Hib porin. The threshold voltage for gating was decreased from 75 to 40 mV. At 80 mV, steady-state conductance for succinylated porin was 50-55% of the instantaneous conductance. Hib porin at 80 mV showed a decrease to 89-91% of the instantaneous current levels. We propose that surface-located lysine residues are determinants of voltage gating for porin of Haemophilus influenzae type b.

Proceedings of the National Academy of Sciences, 2004

Tandem MS has identified 209 proteins of clathrin-coated vesicles (CCVs) isolated from rat brain.... more Tandem MS has identified 209 proteins of clathrin-coated vesicles (CCVs) isolated from rat brain. An overwhelming abundance of peptides were assigned to the clathrin coat with a 1:1 stoichiometry observed for clathrin heavy and light chains and a 2:1 stoichiometry of clathrin heavy chain with clathrin adaptor protein heterotetramers. Thirty-two proteins representing many of the known components of synaptic vesicles (SVs) were identified, supporting that a main function for brain CCVs is to recapture SVs after exocytosis. A ratio of vesicle- N -ethylmaleimide-sensitive factor attachment protein receptors to target- N -ethylmaleimide-sensitive factor attachment protein receptors, similar to that previously detected on SVs, supports a single-step model for SV sorting during CCV-mediated recycling of SVs. The uncovering of eight previously undescribed proteins, four of which have to date been linked to clathrin-mediated trafficking, further attests to the value of the current organelle-...

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 1999

Liquid chromatography/mass spectrometry using electrospray ionisation was used to analyse rhamnol... more Liquid chromatography/mass spectrometry using electrospray ionisation was used to analyse rhamnolipids produced by a Pseudomonas aeruginosa strain with mannitol or naphthalene as carbon source. Identification and quantification of 28 different rhamnolipid congeners was accomplished using a reverse-phase C18 column and a 30 min chromatographic run. Isomeric rhamnolipids that were not chromatographically resolved could be identified by interpretation of their mass

Molecular & Cellular Proteomics, 2006

Immunogenetics, 2002

The B6 dom1 minor histocompatibility antigen (MiHA) is a model antigen, since it is both the epit... more The B6 dom1 minor histocompatibility antigen (MiHA) is a model antigen, since it is both the epitome of an immunodominant epitope and an ideal target for adoptive cancer immunotherapy. Based on DNA sequencing and MS/MS analyses, we report that B6 dom1 corresponds to amino acids 770-778 (KAPDNRETL) of a protein we propose to call SIMP (source of immunodominant MHC-associated peptides) that is encoded by a mouse homolog of the yeast STT3 gene. STT3, a member of the oligosaccharyltransferase complex, is essential for cell proliferation. Phenotypic and genotypic analyses among eight strains of mice revealed a precise correlation between susceptibility or resistance to B6 dom1-specific cytotoxic T lymphocytes (CTLs) and the presence of a Glu vs Asp amino acid at position 776 of the SIMP protein, respectively. Strikingly, while the difference in the amino acid sequence 770-778 encoded by the two SIMP alleles represents a very conservative substitution, these allelic peptides were not crossreactive at the CTL level, and both peptides were immunodominant when presented to mice homozygous for the opposite allele. In addition, we have cloned a human ortholog of SIMP whose predicted protein shares 97% amino acid identity with mouse SIMP. These results strengthen the concept that MHC class-I-associated MiHAs originate as a consequence of rare polymorphisms among highly conserved genes. Furthermore, the notion that a peptide differing from a self analog by a single methylene group can be immunodominant has implications regarding our understanding of the mechanisms of immunodominance.

International Journal of Pharmaceutical Compounding

The purpose of this study was to determine the room temperature stability over a period of severa... more The purpose of this study was to determine the room temperature stability over a period of several months of commercially available intravenous succinylcholine dichloride (Quelicin, 20 mg/mL) in vials. A previously validated electro-spray tandem mass spectrometry method developed for the determination of succinylcholine dichloride in plasma was used. This method was based upon a stable isotope dilution assay using hexadeuterosuccinylcholine diiodide as the internal standard and was shown to be specific, sensitive, and reproducible. Calibration curves were plots of the ratios of intensities of the major product ions in the collision-induced dissociation spectrum for known concentration ratios of succinylcholine dichloride and hexadeuterosuccinylcholine diiodide in solutions. The concentration of succinylcholine dichloride was shown to decline linearly. After 1, 3, and 6 months at room temperature, the vial contents retained approximately 98%, 95%, and 90% of their inital concentration, respectively. We suggest, therefore, that succinylcholine dichloride can be stored safely at room temperature under normal daylight for 6 months.