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Biomedical subjects

R Baggio

Publications and source records attributed to R Baggio.

10 recordsLinked to original sources
PubMed2001

catena-Poly[[diaqua(1,10-phenanthrolone-N,N')manganese(II)]-mu-(thiosulfato-O:S] and bis(2,2'-bi-pyridyl-N,N')(tetrathionato-O,O')-manganese(II).

The structures of [Mn(S2O3)2(C12H8N2)(H2O(2)] and [Mn(S4O6)(C10H8N2)(2)] are presented. The former consists of pairs of polymeric chains formed by manganese polyhedra bridged by bidentate thiosulfate anions, which are in turn related to each other by a pseudo-twofold screw axis. The latter has crystallographic twofold symmetry and consists of monomers in which manganese displays its typical octahedral coordination provided by the bidentate bites of two bipyridine bases and a tetrathionate anion, which is, to our knowledge, the first chelating tetrathionate to be reported in the literature.

Journal Article↗
PubMed2000

Bis(1,10-phenanthroline-N,N')(thiosulfato-O, S)nickel(II)-water-methanol (1/0.92/1.4) and bis(2,2'-bipyridyl-N, N')(thiosulfato-O,S)nickel(II)-water-methanol (1/2/0.55)

The title compounds, [Ni(S(2)O(3))(C(12)H(8)N(2))(2)].0.92H(2)O.1. 4CH(4)O and [Ni(S(2)O(3))(C(10)H(8)N(2))(2)].2H(2)O.0.55CH(4)O, are monomeric, containing nickel(II) in a distorted octahedral coordination environment provided by the four N atoms of two bidentate bipy or phen groups and one S and one O atom from a chelating thiosulfate anion. The crystals are highly unstable outside their mother liquors and are stabilized in solution by a not fully determined number of water and methanol solvate molecules. The phenanthroline structure includes two independent moieties related by a non-crystallographic inversion center. The thiosulfate anions display the usual S-O lengthening found when the anion acts in a bidentate mode.

Journal Article↗
PubMed2000

Bis

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Journal Article↗
PubMed1999

Safety and efficacy of high-purity concentrates in haemophiliac patients undergoing surgery by continuous infusion.

In this study we explore the feasibility of high-purity double-inactivated concentrates by continuous infusion for the treatment of haemophiliacs in a group of patients undergoing different surgical procedures. The patients were enrolled in the study on the basis of their transfusion history, which was well known due to their long-term follow up at our Haemophilia Center. We did not perform a pre-operative pharmacokinetic study because one of the aims of this study was to demonstrate that continuous infusion can become a first choice standard treatment in patients with haemophilia. Fourteen haemophilia A and one haemophilia B patients who needed at least 5 days of replacement therapy were monitored for haemostatic efficacy, post-operative factor VIII and factor IX levels and evaluated for safety and flexibility of the products. The infusion rate of 3 IU kg-1 h-1 was demonstrated to be sufficient to ensure haemostasis and patients did not need additional bolus infusion during the post-operative period. Our study demonstrates the safety and feasibility of high-purity concentrates in patients undergoing surgery by continuous infusion, also in the absence of a previous pharmacokinetic study.

Adult↗
PubMed1999

Biochemical and functional profile of a newly developed potent and isozyme-selective arginase inhibitor.

An increase in arginase activity has been associated with the pathophysiology of a number of conditions, including an impairment in nonadrenergic and noncholinergic (NANC) nerve-mediated relaxation of the gastrointestinal smooth muscle. An arginase inhibitor may rectify this condition. We compared the effects of a newly designed arginase inhibitor, 2(S)-amino-6-boronohexanoic acid (ABH), with the currently available N(omega)-hydroxy-L-arginine (L-HO-Arg), on the NANC nerve-mediated internal anal sphincter (IAS) smooth-muscle relaxation and the arginase activity in the IAS and other tissues. Arginase caused an attenuation of the IAS smooth-muscle relaxations by NANC nerve stimulation that was restored by the arginase inhibitors. L-HO-Arg but not ABH caused dose-dependent and complete reversal of N(omega)-nitro-L-arginine-suppressed IAS relaxation that was similar to that seen with L-arginine. Both ABH and L-HO-Arg caused an augmentation of NANC nerve-mediated relaxation of the IAS. In the IAS, ABH was found to be approximately 250 times more potent than L-HO-Arg in inhibiting the arginase activity. L-HO-Arg was found to be 10 to 18 times more potent in inhibiting the arginase activity in the liver than in nonhepatic tissues. We conclude that arginase plays a significant role in the regulation of nitric oxide synthase-mediated NANC relaxation in the IAS. The advent of new and selective arginase inhibitors may play a significant role in the discrimination of arginase isozymes and have important pathophysiological and therapeutic implications in gastrointestinal motility disorders.

Amino Acids↗
PubMed1996

From good substrates to good inhibitors: design of inhibitors for serine and thiol proteases.

Serine and thiol proteases react with peptide substrates to form an acyl-enzyme. We have synthesized inhibitors which are pseudo-substrates and react with the proteases to generate acyl-enzymes which hydrolize slowly. This is achieved by incorporating an electron-donating group near the carbonyl group of inhibitors I [Ac-Phe--C(O)NH--NH--C(O)X] and II [benzyl-O-C(O)-psiAla-Leu-ArgOMe]. The acyl-enzymes derived from the reaction of I with papain and II with chymotrypsin hydrolyze with t1/2 of 12 and 1 h, respectively. The increased electron density on the carbonyl group of the inhibitor also reduces the rate of acyl-enzyme formation. Components were incorporated into the inhibitor which interact with the leaving group binding site (S' subsite) and which accelerate the rate of reaction of inhibitor with enzyme. For inhibitor I, X = NH(CH3), k(on) < 0.13 M(-1) s(-1) for the reaction papain, but if X = psiLeu(CH3)2,k(on) =10(5) M(-1) s(-1). Similar results were obtained with II and chymotrypsin. Concomitant with acyl-enzyme formation, X is released and a slowly hydrolyzing acyl-enzyme remains.

Cysteine Proteinase Inhibitors↗