A modified method of hepaticocholedochojejunal anastomosis

"Declive" latero-terminal and latero-lateral hepaticocholedocho-jejunoanastomosis with a loop of the small intestine isolated by the Roux method was carried out in 6 patients (5 females and 1 male) according to absolute indications. In this type of anastomosis, the longitudinal incision in the hepaticocholedochus is made not on the midline but latero-dorsally on its right supraduodenal circumference. The anastomosis is formed by means of a modified suture or a suture commonly used for bilio-digestive anastomoses; the needle is inserted through the wall of the bile duct 2-2.5 mm from the border of its opening and the sutures are placed at a similar distance from one another, the seromusculo-submucous sutures are applied 6-7 mm from the edge of the opening and at a distance of 3-3.5 mm from one another. Comparison with patients in whom heapticocholedochojejunoanastomosis was established by the routine method showed the results to be better in the modified method.     

Studies on the plasma cholesterol and triacylglycerols in chronic methemoglobinemia in rats.

Plasma cholesterol and triacylglycerols were measured in rats with modelled chronic two-stage (mild and moderate) intermittent nitrite methemoglobinemia for 15 and 30 days. It was found that at the moment of methemoglobinemic peak (60 +/- 10 min) the experimental animals had mixed (hemtoxic, anemic and hypoxic) hypoxemia. The every day "pulse" decrease of the total oxygen concentration during the 30-day methemoglobinemia was accompanied with a significant rise (p < 0.05) of cholesterol concentrations in the high-density lipoproteins and the total cholesterol, as well as a decrease in the amount of triacylglycerols. These changes are considered to represent the side effects of adaptation for whose elucidation further research is needed.     

Dissecting human cytomegalovirus gene function and capsid maturation by ribozyme targeting and electron cryomicroscopy

Human CMV (HCMV) is the leading viral cause of birth defects and causes one of the most common opportunistic infections among transplant recipients and AIDS patients. Cleavage of internal scaffolding proteins by the viral protease (Pr) occurs during HCMV capsid assembly. To gain insight into the mechanism of HCMV capsid maturation and the roles of the Pr in viral replication, an RNase P ribozyme was engineered to target the Pr mRNA and down-regulate its expression by >99%, generating premature Pr-minus capsids. Furthermore, scaffolding protein processing and DNA encapsidation were inhibited by 99%, and viral growth was reduced by 10,000-fold. 3D structural comparison of the Pr-minus and wild-type B capsids by electron cryomicroscopy, at an unprecedented 12.5-angstroms resolution, unexpectedly revealed that the structures are identical in their overall shape and organization. However, the Pr-minus capsid contains tenuous connections between the scaffold and the capsid shell, whereas the wild-type B capsid has extra densities in its core that may represent the viral Pr. Our findings indicate that cleavage of the scaffolding protein is not associated with the morphological changes that occur during capsid maturation. Instead, the protease appears to be required for DNA encapsidation and the subsequent maturation steps leading to infectious progeny. These results therefore provide key insights into an essential step of HCMV infection using an RNase P ribozyme-based inhibition strategy.     

Protonation of the beta-lactam nitrogen is the trigger event in the catalytic action of class A beta-lactamases

The pH dependence of the pK(a) values of all ionizable groups and of the electrostatic potential at grid points corresponding to catalytically important atoms in the active site of TEM-1 beta-lactamase has been calculated by a mean-field approach for reaction intermediates modeled on the basis of energy minimized x-ray crystallographic coordinates. By estimating electrostatic contributions to the free energy changes accompanying the conversion of the free enzyme into the acylenzyme reaction intermediate, we found that acid-catalyzed protonation of the beta-lactam nitrogen is energetically favored as the initiating event, followed by base-catalyzed nucleophilic attack on the carbonyl carbon of the beta-lactam group. N-protonation is catalyzed through a hydrogen-bonded cluster involving the 2-carboxylate group of the substrate, the side chains of S130 and K234, and a solvent molecule. Nucleophilic attack on the carbonyl carbon is carried out by the side chain of S70 with proton abstraction catalyzed by a water molecule hydrogen-bonded to the side chain of E166. Stabilization of ion pairs in the active site through interactions with distant clusters of charged residues in the enzyme was concluded to be an important driving force of the catalytic mechanism.     

Effect of the water extract of Galega officinalis L. on human platelet aggregation in vitro

Galega officinalis L. is a traditional medicinal plant from Bulgaria. It was found that the aqueous extract of Herba Galegae suppressed platelet aggregation in vitro induced by adenosine diphosphate, epinephrine, thrombin and collagen. The compounds with antiaggregating action have not as yet been isolated from Galega officinalis.     

Anti-platelet fraction from Galega officinalis L. inhibits platelet aggregation

A fraction from crude extract of Galega officinalis L. was purified by gel filtration on Sephadex G-25, Sepharose 4B, and ion-exchange chromatography on diethylaminoethyl (DEAE)-cellulose. The fraction with molecular weight 100-140 kDa appears to have a polysaccharide nature, including protein. The fraction inhibits platelet aggregation initiated by 25 microM adenosine 5'-diphosphate (ADP), 100 microg/ml collagen, and 0.8 U/ml thrombin with the 50% inhibiting concentration (IC(50)) being 11.2 microg/ml for ADP, and the IC(100) being 15.1 microg/ml for collagen and IC(100) 19.6 microg/ml for thrombin.