Identified a morpholinyl-4-piperidinylacetic acid derivative as a potent oral active VLA-4 antagonist

An investigation into the structure-activity relationship of a lead compound, prolyl-5-aminopentanoic acid 4, led to the identification of a novel series of 4-piperidinylacetic acid, 1-piperazinylacetic acid, and 4-aminobenzoic acid derivatives as potent VLA-4 antagonists with low nanomolar IC(50) values. A representative compound morpholinyl-4-piperidinylacetic acid derivative (13d: IC(50)=4.4 nM) showed efficacy in the Ascaris-antigen sensitized murine airway inflammation model by oral administration.     

Radioprotection of lungs by amifostine is associated with reduction in profibrogenic cytokine activity

Radiation-induced pulmonary toxicity causes significant morbidity and mortality in patients irradiated for lung cancer, breast cancer, lymphoma or thymoma. Amifostine is an important drug in the emerging field of cytoprotection. Recent advances in our understanding of the mechanism of radiation-induced injury at the molecular and cellular levels have stimulated interest in the development of effective radioprotective strategies. Accumulation of macrophages with associated production of reactive oxygen species (ROS) and production and activation of cytokines is a key process involved in the pathophysiology of radiation injury in the lung. The purpose of this study was to determine whether the mechanism of radioprotection by amifostine includes reduction in both macrophage activity and the expression and activation of profibrogenic cytokines. Our results demonstrated a reduction in both functional and histological radiation-induced lung injury by amifostine. In addition, this study is the first to demonstrate that amifostine given prior to irradiation reduced both the accumulation of macrophages and the expression/activation of lung tissue Tgfb1 which was followed by the reduction of plasma Tgfb1 levels during the development of radiation-induced lung injury. Future studies are needed to determine whether administration of amifostine both during and after radiotherapy may further increase its radioprotective effect.     

Structural basis for alpha1 versus alpha2 isoform-distinct behavior of the Na,K-ATPase

We showed earlier that the kinetic behavior of the alpha2 isoform of the Na,K-ATPase differs from the ubiquitous alpha1 isoform primarily by a shift in the steady-state E(1)/E(2) equilibrium of alpha2 in favor of E(1) form(s). The aim of the present study was to identify regions of the alpha chain that confer the alpha1/alpha2 distinct behavior using a mutagenesis and chimera approach. Criteria to assess shifts in conformational equilibrium included (i) K(+) sensitivity of Na-ATPase measured at micromolar ATP, under which condition E(2)(K(+)) --> E(1) + K(+) becomes rate-limiting, (ii) changes in K'(ATP) for low affinity ATP binding, (iii) vanadate sensitivity of Na,K-ATPase activity, and (iv) the rate of the partial reaction E(1)P --> E(2)P. We first confirmed that interactions between the cytoplasmic domains of alpha2 that modulate conformational shifts are fundamentally similar to those of alpha1, suggesting that the predilection of alpha2 for E(1) state(s) is due to differences in primary structure of the two isoforms. Kinetic behavior of the alpha1/alpha2 chimeras indicates that the difference in E(1)/E(2) poise of the two isoforms cannot be accounted for by their notably distinct N termini, but rather by the front segment extending from the cytoplasmic N terminus to the C-terminal end of the extracellular loop between transmembranes 3 and 4, with a lesser contribution of the alpha1/alpha2 divergent portion within the M4-M5 loop near the ATP binding domain. In addition, we show that the E(1) shift of alpha2 results primarily from differences in the conformational transition of the dephosphoenzyme, (E(2)(K(+)) --> E(1) + K(+)), rather than phosphoenzyme (E(1)P --> E(2)P).     

Localization of glycogen in the placenta and fetal and maternal livers of cadmium-exposed diabetic pregnant rats

This study was designed to investigate the effects of Cd exposure on the glycogen localization in the placenta and in fetal and maternal livers in streptozotocin (STZ)-induced-diabetic pregnant rats. Ninety-nine virgin female Wistar rats (200–220 g) were mated with 33 males for at least 12 h. From the onset of pregnancy, the rats were divided into four experimental groups (control, Cd treated, STZ treated, and Cd+STZ treated). The Cd-treated group was injected subcutaneously daily with CdCl₂ dissolved in isotonic NaCl, starting at the onset of pregnancy throughout the experiment. Diabetes was induced on d 13 of pregnancy by a single intraperitoneal injection of STZ in the STZ-treated group. In addition to the daily injection of Cd, a single intraperitoneal injection of STZ was also given on d 13 of pregnancy in the Cd+STZ-treated group. The rats received the last injection 24 h before being sacrificed and 10 randomly selected rats in each group were sacrificed on d 15 and d 20 of pregnancy. Blood samples were taken for determination of the serum glucose and insulin levels. Fetal and maternal livers of sacrificed rats in all groups were harvested on d 15 and d 20 of pregnancy, whereas placentas were harvested only on d 20 of pregnancy for histochemical examination. Although both Cd and STZ caused hyperglycemia and decreased insulin secretion, Cd-alone treatment increased the glycogen content only in the placental labyrinth, whereas STZ-alone treatment increased the glycogen content only in the maternal part of the placenta. Increased glycogen localization was observed in both the placental labyrinth and the maternal part of placenta when Cd and STZ were given together. Fetal and meternal livers of control and other treatment groups were not different regarding the glycogen content on d 15 or d 20 of pregnancy. It was concluded that Cd exposure during pregnancy might produce a glycogen localization in the placenta of diabetic rats. However, the function and the mechanisms of increased glycogen contents in the placenta of Cd-exposed pregnant diabetic rats remain unclear and further studies are needed.     

Zinc complexes of benzothiazole-derived Schiff bases with antibacterial activity

Reaction of 2-acetamidobenzaldehyde with 2-amino-, 2-amino-4-methyl-, 2-amino-4-methoxy-, 2-amino-4-chloro-, 2-amino-6-nitro- and 2-amino-6-methylsufonylbenzothiazole afforded a series of Schiff bases. These compounds have been used for complexation reactions to obtain Zn(II) chelates having the same metal ion but different anions of the type [Zn(L)2]Xn [L = Schiff base derivative, X = SO4, NO3, C2O4 and CH3CO2 and n = 1 or 2] These complexes (Table I) have been characterized by physical, spectral, and analytical data. The Schiff bases act tridentately and their metal complexes were proposed to possess an octahedral geometry. To evaluate the antibacterial role of the anion, these compounds have been screened for antibacterial properties against pathogenic strains such as Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa.     

SPINK1 is a susceptibility gene for fibrocalculous pancreatic diabetes in subjects from the Indian subcontinent

Fibrocalculous pancreatic diabetes (FCPD) is a secondary cause of diabetes due to chronic pancreatitis. Since the N34S variant of the SPINK1 trypsin inhibitor gene has been found to partially account for genetic susceptibility to chronic pancreatitis, we used a family-based and case-control approach in two separate ethnic groups from the Indian subcontinent, to determine whether N34S was associated with susceptibility to FCPD. Clear excess transmission of SPINK1 N34S to the probands with FCPD in 69 Bangladeshi families was observed (P<.0001; 20 transmissions and 2 nontransmissions). In the total study group (Bangladeshi and southern Indian) the N34S variant was present in 33% of 180 subjects with FCPD, 4.4% of 861 nondiabetic subjects (odds ratio 10.8; P<.0001 compared with FCPD), 3.7% of 219 subjects with type 2 diabetes, and 10.6% of 354 subjects with early-onset diabetes (aged <30 years) (P=.02 compared with the ethnically matched control group). These results suggest that the N34S variant of SPINK1 is a susceptibility gene for FCPD in the Indian subcontinent, although, by itself, it is not sufficient to cause disease.     

Regulation of capacitative and non-capacitative Ca2+ entry in A7r5 vascular smooth muscle cells

A capacitative Ca2+ entry (CCE) pathway, activated by depletion of intracellular Ca2+ stores, is thought to mediate much of the Ca2+ entry evoked by receptors that stimulate phospholipase C (PLC). However, in A7r5 vascular smooth muscle cells, vasopressin, which stimulates PLC, empties intracellular Ca2+ stores but simultaneously inhibits their ability to activate CCE. The diacylglycerol produced with the IP3 that empties the stores is metabolized to arachidonic and this leads to activation of nitric oxide (NO) synthase, production of NO and cyclic GMP, and consequent activation of protein kinase G. The latter inhibits CCE. In parallel, NO directly activates a non-capacitative Ca2+ entry (NCCE) pathway, which is entirely responsible for the Ca2+ entry that occurs in the presence of vasopressin. This reciprocal regulation of two Ca2+ entry pathways ensures that there is sequential activation of first NCCE in the presence of vasopressin, and then a transient activation of CCE when vasopressin is removed. We suggest that the two routes for Ca2+ entry may selectively direct Ca2+ to processes that mediate activation and then recovery of the cell.     

Antibacterial and antifugal mono- and di-substituted symmetrical and unsymmetrical triazine-derived Schiff-bases and their transition metal complexes

A new series of antibacterial and antifungal triazine-derived mono- and di-substituted (symmetrical and unsymmetrical) Schiff-bases and their cobalt(II), copper(II), nickel(II) and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments and IR and electronic spectral measurements. IR spectra indicated the ligands to act as tridentate towards divalent metal ions via a trazine-N, the azomethine-N and, indole-NH and deprotonated-O of salicylaldehyde. The magnetic moments and electronic spectral data suggest octahedral geometry for the Co(II), Ni(II) and Zn(II)complexes and square-pyramid for Cu(II) complexes. NMR spectral data of the ligands and their diamagnetic zinc(II) complexes well-define their proposed structures/geometries. Elemental analyses data of the ligands and metal complexes agree with their proposed structures/geometries. The synthesized ligands, along with their metal complexes were screened for their antibacterial activity against Escherichia coli, Bacillus subtillis, Shigella flexneri, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata. The results of these studies show the metal complexes to be more antibacterial/ antifungal against two or more species as compared to the uncomplexed Schiff-base ligands.