Analysis of some herbal plants from India used in the control of diabetes mellitus by NAA and AAS techniques

Elemental analysis of some herbal plants used in the control of diabetes has been done by the techniques of Neutron Activation Analysis (NAA) and Atomic Absorption Spectroscopy (AAS). The elements Mn, Na, K, Cl, Al, Cu, Co, Pb, Ni, Cr, Cd, Fe, Ca, Zn and Hg are found to be present in different plants in various proportions.     

Study of the beta -delayed neutron decay of 18N

The shortage of suitable liver donors for children has motivated the use of ABO-incompatible (ABO-I) grafts for transplantation in urgent situations. However, survival after ABO-I liver grafts has been reported at about 30% as compared with 80% in cases of ABO-identical or -compatible liver grafts. This difference has been attributed to antibody-mediated, hyperacute or chronic liver rejection, due to preformed ABO antibodies (alloantibodies). In this study, we report our results with ABO-I livers in children without alloantibodies at the time of transplantation. From January 1988 to June 1993, 143 OLT were performed in 122 children. Eight children received 8 ABO-I liver grafts. Of these, 7 patients were included in the study. All 7 were alloantibody free before OLT. Five children were spontaneously alloantibody free, while in 2 children, the plasma alloantibodies were eliminated before and after transplantation using intravenous infusion of specific blood group antigens of the donor blood group (soluble antigens). Immunosuppression consisted of a triple-drug treatment combining CsA, AZA, and steroids. The follow-up period was between 10 and 48 months. One child died from a surgical complication. Six children survived, but 1 died 10 months later from intestinal obstruction. There were no graft losses and no episodes of hyperacute or chronic rejection. The graft and patient survival rate was 71%. There was a 28% incidence of rejection, but all were mild (requiring steroid boluses only). Our results suggest that the absence of ABO alloantibodies at the time of and after transplantation can protect ABO-I liver grafts against antibody-mediated rejection, whether hyperacute or chronic, and that soluble antigens are effective in eliminating alloantibodies in children.     

Working memory and work with memory: visual-spatial and further components of processing

Empirical and theoretical evidence for the concept of working memory is considered. We argue that the major weakness of this concept is its loose connection with the knowledge about background perceptive and cognitive processes. Results of two relevant experiments are provided. The first study demonstrated the classical chunking effect in a speeded visual search and comparison task, the proper domain of a large-capacity very short term sensory store. Our second study was a kind of extended levels-of-processing experiment. We attempted to manipulate visual, phonological, and (different) executive components of long-term memory in the hope of finding some systematic relationships between these forms of processing. Indeed, the results demonstrated a high degree of systematicity without any apparent need for a concept such as working memory for the explanation. Accordingly, the place for working memory is at all the interfaces where our metacognitive strategies interfere with mostly domain-specific cognitive mechanisms. Working memory is simply our work with memory.     

Plateletapheresis with a next generation blood cell separator

Baeyer-Villiger monooxygenases (BVMOs) are enzymes able to perform highly regio-plus steroselective nucleophilic and electrophilic biooxygenations on various substrates. The resultant chiral products (lactones and sulfoxides) can be valuable for the chemoenzymatic synthesis of a wide range of useful compounds. Recent studies have provided a number of alternative active-site models that attempt to explain the exquisite and unusual selectivity of BVMOs. This article reviews some of the established applications, and considers the merits of the various predictive models.     

The neurotoxicity of sulfur-containing amino acids in energy-deprived rat hippocampal slices

The rat hippocampal slice preparation and its electrophysiology were used to assess the toxicity of two sulfur-containing amino acids, L-cysteate (CA) and L-cysteine (CYS). Both compounds were innocuous under normal conditions but became toxic in energy-deprived (lack of oxygen or glucose) slices. CA and CYS toxicity was apparent as both reduced the number of slices that normally recover their neuronal function (evoked CA1 population spike) after a standardized period of hypoxia or glucose deprivation (GD). The competitive N-methyl-D-aspartate (NMDA) antagonist DL-2-amino-5-phosphonovalerate blocked the toxicity of both CA and CYS in hypoxic slices, but it was effective only against CYS toxicity in glucose-deprived slices. The glycine antagonist 7-chlorokynurenate blocked CA and CYS toxicity in hypoxic slices but was unable to block their toxicity in glucose-deprived tissue. Perfusing slices with medium containing a high magnesium concentration blocked the toxicity of CA in both hypoxic and glucose-deprived slices, a treatment that was ineffective against CYS toxicity under either condition. Calcium depletion from the perfusion medium completely blocked the damaging effect of both amino acids in hypoxic slices, but it only partially blocked the toxicity of CA and did not block that of CYS in glucose-deprived slices. These results suggest that CA and CYS activate different NMDA receptor subsets and other glutamate receptor subtypes. Moreover, the results indicate a possible difference between the mechanism that lead to hypoxic neuronal damage and the one that lead to hypoglycemic neuronal damage.     

Epitope specificity of CD44 for monoclonal antibody-dependent facilitation of marrow engraftment in a canine model

Primary graft rejection after marrow transplantation occurs more frequently in patients receiving HLA-haploidentical compared with HLA-identical sibling transplants. Both human and experimental animal data suggest that the cells responsible for this phenomenon are either host natural killer (NK) cells, T cells, or both. To investigate the mechanisms of graft rejection, we have developed a canine model of marrow transplantation, which uses DLA-nonidentical unrelated donors in the absence of postgrafting immunosuppression. In this model most animals rejected their marrow grafts after a preparative regimen of 9.2 Gy total body irradiation (TBI). However, engraftment of DLA-nonidentical marrow can be facilitated when the recipients are pretreated with monoclonal antibody (MoAb) S5, which recognizes CD44. In this report, we extended these observations by first cloning the canine CD44 and, next, mapping the epitope recognized by S5, which was located in a region conserved among human and canine CD44 and was distinct from the hyaluronan binding domain. However, in vitro binding of S5 caused a conformational change in CD44, which allowed increased hyaluronan binding. Then, we reexamined the in vivo model of marrow transplantation and compared results with MoAb S5 to those with two other anti-CD44 MoAbs, IM7 and S3. Only MoAb S5 significantly increased the engraftment rate of DLA-nonidentical unrelated marrow, whereas the two other anti-CD44 MoAbs were ineffective. The enhanced in vivo effect was not related to differences in the MoAbs' avidities, since both S5 and IM7 had equivalent binding to CD44, but most likely related to the specific epitope that S5 recognizes. Thus, this study shows that the effect of the anti-CD44 MoAb S5 in facilitating engraftment is epitope specific and if one is to use an anti-CD44 to facilitate engraftment of marrow in humans, one cannot assume that any anti-CD44 would work.