Om P. Srivastava

Combined glycomimetic and multivalent strategies for the design of potent selectin antagonists

Abstract Stepwise large scale synthesis of 3′-sulfo-Lewis x -Glc mimetic of the lead anti-inflammatory agent sialyl Lewis x in a form suitable for copolymerization with acrylamide has been achieved. The resulting watersoluble copolyacrylamide showed inhibition of binding of both L-and E-selectins in the μMolar range.

Effect of Sulfo Lewis C on smoke inhalation injury in an ovine model

OBJECTIVEnTo evaluate the effect of Sulfo Lewis C (SO3-3âGal1-3GlcNAc-O(CH2)8-COOMe), a putative ligand of selectins, on smoke inhalation injury.nnnDESIGNnProspective animal study with concurrent controls.nnnSETTINGnAn animal laboratory.nnnSUBJECTSnTwelve 1-yr-old female sheep, weighing 24 to 33 kg.nnnINTERVENTIONSnTwelve sheep received nine exposure units of smoke generated by thermolysis of pine woodchips (80 g). Group 1 (n = 6) was untreated. Group 2 (n = 6) was treated with an intravenous infusion of Sulfo Lewis C after smoke exposure. Animals were killed 48 hrs after injury.nnnMEASUREMENTS AND MAIN RESULTSnCardiopulmonary variables and blood gases were measured serially. Granulocyte free-radical production was measured before smoke exposure and at 4 and 48 hrs after injury. Ventilation/perfusion distribution (VA/Q) was analyzed using the multiple inert gas elimination technique. Granulocyte free-radical production was increased after smoke exposure in both groups. Oxygenation was significantly improved by the administration of Sulfo Lewis C. VA/Q analysis demonstrated significantly less blood flow to low VA/Q lung segments in treated animals.nnnCONCLUSIONSnSelectin blockade attenuated lung injury after smoke exposure. These data support the hypothesis that neutrophils play a pivotal role in smoke inhalation injury.

Synthesis of α-d-Glcp-(1 → 2)-α-d-Glcp-(1 → 3)-α-d-Glcp-O-(CH2)8COOCH3 for use in the assay of α-glucosidase I activity

The chemical synthesis of alpha-D-Glcp-(1-->2)-alpha-D-Glcp p-(1-->3) -alpha-D-Glcp-O-(CH2)8 COOCH3 (9), a substrate specific for alpha-glucosidase I, is reported. This enzyme removes the terminal alpha-D-Glcp unit to produce alpha-D-Glcp-(1-->3)-alpha-D-Glcp-O-(CH2)8 COOCH3 (10). This is the first synthetic substrate described for glucosidase I that allows kinetic evaluation of substrates and inhibitors of this enzyme. Tetramethylrhodamine was coupled to 9 through an ethylenediamine linker to produce a brilliant red derivative. Addition of this fluorescent dye did not affect enzyme binding to the substrate, as determined by a comparison of the Km value (1.3 mM). The fluorescent label allows visual detection of 2-3 pmol of product by TLC.

Selectin blockade worsened lipopolysaccharide-induced lung injury in a swine model.

BACKGROUNDnPolymorphonuclear leukocytes have been reported to play an important role in various acute lung injuries. Neutrophil recruitment into tissues is a multistep process involving sequential engagement of adhesion molecules. The objective of this study was to determine the effect of selectin inactivation with Sulfo Lewis C (SO3-3betaGal1-3betaGlcNAc-O(CH2)8-COOMe) on the pulmonary response to lipopolysaccharide (LPS) infusion.nnnMETHODSnAll animals (n = 11) were pretreated with an intramuscular injection of a priming dose of Escherichia coli LPS (10 microg/kg). Eighteen hours later, animals received an intravenous infusion of LPS (20 microg/kg) over 20 minutes. All animals were resuscitated with a lactated Ringers solution. Group I (G1; n = 5) received no additional treatment. Group II (G2; n = 6) received a bolus injection of Sulfo Lewis C (10 mg/kg) 10 minutes before LPS insult followed by a continuous infusion (1 mg/kg per hour) for the rest of the study. Animals were observed for 5 hours from initiation of the LPS infusion and killed. Cardiopulmonary variables and blood gases were measured serially. The multiple inert gas elimination technique (MIGET) was used to evaluate the matching of air flow and blood flow in the lung 5 hours after LPS infusion. Histologic evaluation of the parenchymal injury was performed by using light microscopy. The number of polymorphonuclear leukocytes and red blood cells in the alveolar spaces per field at 400x magnification were counted in 10 randomly selected fields.nnnRESULTSnHypoxemia, indexed as Pao2/FIO2, was exacerbated by the administration of Sulfo Lewis C (G1:437+/-33 vs. G2: 241+/-63 mm Hg at 5 hours, p<0.03). This finding is supported by the multiple inert gas elimination technique analysis, which demonstrated significantly greater blood flow to true shunt in G2 (G1:4.42+/-1.75 vs. G2:23.2+/-5.69, p<0.02). There was no difference between the two groups in red blood cell counts in the alveolar spaces. However, polymorphonuclear leukocyte counts were significantly greater in G2 (G1:1.8+/-0.58 vs. G2:9.9+/-2.34, p<0.01).nnnCONCLUSIONnSelectin blockade significantly worsened lung injury induced by LPS infusion, and greater numbers of neutrophils were observed in alveolar spaces in the group treated with Sulfo Lewis C. These findings are supported by the multiple inert gas elimination technique analysis, which demonstrated significantly greater blood flow to the true shunt compartment in treated animals. Further studies are required to determine the role of selectins in sepsis-induced lung injury.