Anticoagulant effect of Naja naja venom 5'nucleotidase: demonstration through the use of novel specific inhibitor, vanillic acid.

The snake venom proteins affect hemostasis by either advancing/delaying blood coagulation. Apart from proteases and phospholipase A(2)s (PLA(2)s), 5'nucleotidase is known to affect hemostasis by inhibiting platelet aggregation. In this study, the possible involvement of Naja naja venom 5'nucleotidase in mediating anticoagulant affect is evaluated. Vanillic acid selectively and specifically inhibited 5'nucleotidase activity among other enzymes present in N. naja venom. It is a competitive inhibitor as evident of inhibition relieving upon increased substrate concentration. Vanillic acid dose dependently inhibited the anticoagulant effect of N. naja venom up to 40%. This partial involvement of 5'nucleotidase in mediating anticoagulant effect is substantiated by concanavalin-A (Con-A) inhibition studies. Con-A, competitively inhibited in vitro protease and 5'nucleotidase activity up to 100%. However, it did not exhibit inhibitory activity on PLA(2). The complete inhibition of anticoagulant effect by Con-A upon recalcification time suggests the participation of both 5'nucleotidase and protease in mediating anticoagulant effect of N. naja venom. Vanillic acid and Con-A inhibition studies together suggest that probably 5'nucleotidase interacts with one or more factors of intrinsic pathway of blood coagulation to bring about anticoagulant effect. Thus, this study for the first time demonstrates the involvement of 5'nucleotidase in mediating N. naja venom anticoagulant effect.     

Haemodialysis activates phospholipase A2 enzyme

BACKGROUND: Clinical and experimental evidence suggest that haemodialysis(HD) procedure is an inflammatory process. For the productionof proinflammatory lipid mediators in many inflammatory reactions,the release of arachidonic acid by phospholipase A₂ (PLA₂ enzymeis a prerequisite. Therefore, the purpose of the present investigationwas to establish whether the activity of PLA₂ increases duringHD and whether the increase depends on the type of dialyserused. METHODS: We performed dialysis in eight chronic HD patients. Blood samplesentering and leaving the dialyser were obtained before and at15, 60, 120 and 180 min after the dialysis was started, on oneoccasion using a cuprophane and on another occasion a cellulosetriacetate dialyser. PLA₂ activity was assessed in crude plasmaand in plasma extract. RESULTS: PLA₂ activity in plasma extract exhibited similar biochemicalproperties to that of inflammatory human synovial fluid PLA₂enzyme which is of group II PLA₂. PLA₂ activity in crude plasmarepresents a type of PLA₂ other than the synovial type. In HDpatients, baseline PLA₂ activities in crude plasma and plasmaextract were significantly increased when compared to normalsubjects. An increase in PLA₂ activity was observed in crudeplasma with a peak appearing at 15 min when the patients weredialysed with cuprophane and cellulose triacetate membranes.This increase was observed in both arterial and venous bloodsamples and was more pronounced when the patients were dialysedwith cuprophane than with cellulose triacetate membranes. WhenPLA₂ was assessed in plasma extract, the activity increasedonly with cuprophane but not with cellulose triacetate membranes. CONCLUSIONS: PLA₂ activity in plasma is increased in HD patients and increasesduring the dialysis procedure to a greater extent with a lessbiocompatible membrane. Continuous activation of PLA₂ mightbe relevant for long-term deleterious consequences of HD.     

Why pictures look right when viewed from the wrong place

A picture viewed from its center of projection generates the same retinal image as the original scene, so the viewer perceives the scene correctly. When a picture is viewed from other locations, the retinal image specifies a different scene, but we normally do not notice the changes. We investigated the mechanism underlying this perceptual invariance by studying the perceived shapes of pictured objects viewed from various locations. We also manipulated information about the orientation of the picture surface. When binocular information for surface orientation was available, perceived shape was nearly invariant across a wide range of viewing angles. By varying the projection angle and the position of a stimulus in the picture, we found that invariance is achieved through an estimate of local surface orientation, not from geometric information in the picture. We present a model that explains invariance and other phenomena (such as perceived distortions in wide-angle pictures).     

Hallervorden Spatz Disease

A nine-month-old infant presented with fever and loss of milestones. Examination revealed intermittent rigidity and dystonic movements. Magnetic resonance imaging (MRI) shows decreased signal intensity in globus pallidus and substantia nigra, indicative of iron deposition, suggesting Hallervorden Spatz Disease. The dopamine–neuromelanine system has been postulated to be the possible pathogenesis. Gene mapping has located the defect to be in the coding sequence of a gene called PANK– 2. Prenatal diagnosis is possible. The case is reported because of its rarity and early presentation.     

Modulation of J774.1 macrophage L-arginine metabolism by intracellular Mycobacterium bovis BCG

Using a Mycobacterium bovis BCG mutant (AS1) lacking a Bacillus subtilis L-arginine transporter homolog, we demonstrate here that the interaction between intracellular mycobacteria and the macrophage with respect to L-arginine transport and metabolism is quite complex. Intracellular AS1 stimulates macrophage L-arginine transport and accumulates 2.5-fold more (3)H label derived from L-arginine than does the wild type. These studies suggest that the accumulation of (3)H label reflects the acquisition of metabolites of L-arginine produced by the macrophage.     

Discordant expression of selectin ligands and sialyl Lewis x-related epitopes on murine myeloid cells

Murine leukocytes are thought to express alpha2-3-sialylated and alpha1-3-fucosylated selectin ligands such as sialyl Lewis x (sLe(x)), although monoclonal antibodies (mAbs) to sLe(x) or Le(x) reportedly do not bind to murine leukocytes. We observed that P- and E-selectin bound to pronase-sensitive ligands on murine monocytic WEHI-3 cells and murine neutrophils, indicating that the ligands for both selectins are glycoproteins. CSLEX-1, HECA-452, and other widely used mAbs to sLe(x) and Le(x) did not bind to WEHI-3 cells and bound at very low levels to murine neutrophils. Only the anti-sLe(x) mAbs 2H5 and KM93, which also recognize nonfucosylated glycans, bound to WEHI-3 cells. 2H5 and KM93 bound to pronase-resistant structures, indicating that the mAbs did not identify selectin ligands. Treatment of WEHI-3 cells with glycosidases or chlorate demonstrated that sialic acid modifications, alpha1-3-galactosylation, or sulfation did not mask epitopes for mAbs to sLe(x) or Le(x). Compared to human promyelocytic HL-60 cells, WEHI-3 cells and murine neutrophils expressed low alpha1-3-fucosyltransferase activities. Consistent with very low endogenous fucosylation, forced fucosylation of intact WEHI-3 cells or murine neutrophils by exogenous alpha1-3-fucosyltransferase FTVI and GDP-fucose created many new epitopes for anti-sLe(x) mAbs such as HECA-452 and CSLEX-1. Nevertheless, forced fucosylation of intact cells did not significantly augment their ability to bind to fluid-phase P- or E-selectin or to roll on immobilized P- or E-selectin under flow. These data suggest that murine myeloid leukocytes fucosylate only a few specific glycans, which interact preferentially with P- and E-selectin.     

Posterior reversible encephalopathy syndrome in a patient with hepatitis B induced type 1 membranoproliferative glomerulonephritis

Posterior reversible encephalopathy syndrome (PRES) is a rare complication of nephrotic syndrome and corticosteroid therapy. Here, we discuss an 18 year old man with type 1 membranoproliferative glomerulonephritis (MPGN) secondary to hepatitis B infection who developed posterior leukoencephalopathy while on therapy with lamivudine and prednisone. He developed seizures and vision loss. He also had hypertension, but no sudden elevation was recorded at any time. Magnetic resonance imaging revealed patchy areas of altered signal intensity involving cortical gray and subcortical white matter in the bilateral frontoparietal regions, occipital cortices, temporal cortices and cerebellar hemispheres, and hyperintensity on T2W and FLAIR sequences. Tapering of prednisone and controlling hypertension resulted in clinical improvement within a few days, and in a month MRI was normal. Diagnosing PRES requires a high index of suspicion when treating similarly susceptible patients. PRES as a complication during the treatment of MPGN secondary to hepatitis B has, to our knowledge, never been reported previously in the literature.     

Column-switching liquid chromatographic determination of ML-1035 sulphoxide and its sulphone and sulphide metabolites in rat urine.

A fully automated column-switching LC assay has been developed for the simultaneous determination of a gastroprokinetic agent, ML-1035 sulphoxide, and its sulphone and sulphide metabolites in rat urine. ML-1035 Sulphoxide is a metoclopramide analogue. The method involved direct injection of a diluted urine sample into a CN extraction column for sample clean-up. Polar urine components, including proteins, were flushed to waste. The retained compounds were then eluted onto a C8 analytical column for further separation and analysis by fluorescence detection. After the subsequent washing and re-equilibration with a sequence of three solvent mixtures, the extraction column was ready for the next injection. The recovery of the compounds from the extraction column was 85-90%. The limit of quantitation for all compounds of interest was 25 ng ml-1 or lower, using a 100 microliters specimen of urine. Good inter-day precision (2.1-10.0%), accuracy (0.3-18.0%), and linearity were obtained for all compounds over a range of 25-1000 ng ml-1. The applicability of the LC method was validated with urine samples from rats that had received ML-1035 sulphoxide.     

Intraoperative Inguinal Measurements to Estimate a Single Optimal Mesh Size for Lichtenstein Inguinal Hernioplasty: an Observational Study

In inguinal hernia surgery, use of optimal mesh size during Lichtenstein hernioplasty technique is essential in preventing recurrence. This study was an attempt to determine a single optimal mesh size which can be adapted in vast majority of cases based on intraoperative inguinal measurements. This observational study was done for 1 year in the Department of Surgery, KLES Dr. Prabhakar Kore Hospital and Medical Research Centre, Belagavi, India. A total of 60 patients aged above 18 years who were scheduled for elective inguinal hernioplasty using the Lichtenstein technique for direct or indirect inguinal hernia were subjected to intraoperative measurements. All the patients were male with mean age of 52.75 ± 15.39 years. Mean body mass index (BMI) was 24.51 ± 3.10 kg/m². With regard to hernia characteristics, most of the patients had right-sided hernia (61.7%), indirect (51.67%), and incomplete hernia (81.67%). The mean width of mesh required was 6.65 ± 0.24 cm and mean length was 13.75 ± 0.25 cm. The mesh size was comparable with respect to demographic characteristics, anthropometry, BMI, and type and extent of hernia (p > 0.050) but age and length of mesh size varied significantly in patients with direct and indirect type of hernia (p < 0.050). The present study made an attempt to determine a single optimal mesh size in cases who underwent inguinal hernia repair based on the principles of Lichtenstein hernioplasty, which being 6.7 cm × 13.8 cm. Another significant finding was varying in mesh length size between direct and indirect hernias.     

Hepato-pulmonary amebiasis: a case report

Infections with Entamoeba histolytica are seen worldwide and are more prevalent in the tropics. About 90% of infections are asymptomatic, and the remaining 10% produce a spectrum of clinical syndromes, ranging from dysentery to abscesses of the liver or other organs. Extra-intestinal infection by E. histolytica most often involves liver. Pleuro-pulmonary involvement, seen as the second most common extra-intestinal pattern of infection, is frequently associated with amebic liver abscess. Pulmonary amebiasis occurs in about 2-3% of patients with invasive amebiasis. We report herein the case of a 45-year-old male presenting with hepato-pulmonary amebiasis. The diagnosis was established from direct examination of sputum, in which trophozoites of E. histolytica were detected, and by serology. Following treatment with metronidazole and chloroquine, the clinical evolution improved significantly. On regular follow-up visits, the patient was asymptomatic. This case report reiterates the need for collaboration between clinicians and microbiologists for timely diagnosis of such infections.