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A Khare

Publications and source records attributed to A Khare.

At least 19 recordsLinked to original sources
PubMed2005

Evaluation of markers of endothelial damage in cases of young myocardial infarction.

The pathogenesis of arterial thrombotic disease involves multiple genetic and environmental factors related to atherosclerosis and thrombosis. The endothelium is a monolayer of polygonal cells that extend continuously over the luminal surface of the entire vasculature. Injury to the endothelium leads to dysfunction. The causes of injury include lipids, immune complexes, microorganisms, smoking, hypertension, aging, diabetes mellitus and trauma. Studies have been done to evaluate the role of different adhesion molecules on the endothelial membrane in the pathogenesis of atherosclerosis. These molecules are intercellular adhesion molecule type-1 (ICAM-1), vascular cell adhesion molecule type-1 (VCAM-1), platelet/endothelial cell adhesion molecule-1 (PECAM-1), soluble P-selectin (sP-selectin) and soluble E-selectin (sE-selectin). One-hundred and twenty patients of myocardial infarction (age below 40 years) were recruited from the out-patients department of Department of Cardiology, KEM Hospital, Mumbai. All the patients were recruited 8-10 weeks after stabilization after MI. We estimated the levels of sP-selectin, sE-selectin, sPECAM-1 and serum homocysteine. Healthy age and sex-matched controls and family controls were also recruited in the present study. The levels of sP-selectin, sE-selectin and sPECAM-1 did not differ significantly in cases as compared to controls (p>0.05). Hyperhomocysteinemia was significantly associated with MI in comparison with controls (p<0.001) with an odds ratio of 6.26 (95% confidence limits 3.11-12.76). Folic acid was able to correct hyperhomocysteinemia in a large majority of the cases. Although the levels of sP-selectin, sE-selectin and sPECAM-1 decreased after folic acid therapy, it was only sE-selectin which was significantly reduced (p<0.05). Thus, folic acid had a dual effect in that it reduced hyperhomocysteinemia and sE-selectin which showed a significant reduction on folate supplementation for 15 days.

Adult↗
PubMed2004

Thrombophilia in coronary artery disease: a double jeopardy.

Thrombophilia can be defined as an increased risk of thrombosis. The central event to the pathogenesis of any thrombotic episode is the perturbation of haemostasis, the cause of which may be genetic or environmental. The clinical manifestations of the chronic development of coronary artery atheroma are angina and acute myocardial infarction. In recent years literature is emerging on the role of different factors of blood coagulation in arterial thrombosis. Different coagulation factors, natural anticoagulants, platelet antigens and other factors such as homocysteine, lipoprotein (a), have been studied as risk factors for coronary artery disease (CAD). The results of many of these studies are contradictory. In India, there is an alarming rise in the number of young patients with myocardial infarction (MI) and an interesting feature is that a large majority of these patients lack the conventional risk factors. There have been scattered studies on the thrombophilia status among Indians. The management of thrombophilia can be done by a regimen of different drugs which has been evaluated in different clinical trials. Since the cost of thrombophilia investigations is quite phenomenal for a developing country like India, the selection of these investigations assumes an utmost importance.

Biomarkers↗
PubMed2003

Platelet function tests using platelet aggregometry: need for repetition of the test for diagnosis of defective platelet function.

Four hundred and ninety seven patients were referred to our center for platelet aggregation studies because of spontaneous mucocutaneous bleeds. All these patients had normal complete blood count, platelet count and peripheral smears except in ten patients of Bernard Soulier Syndrome where platelet count was marginally reduced in the presence of giant platelets. Two hundred and eighty patients were found to have normal platelet aggregation to ADP, collagen, ristocetin and arachidonic acid. Out of the remaining 217 patients, 62 patients were diagnosed to have Glanzmanns thrombasthenia, 10 Bernard Soulier Syndrome, 6 storage pool deficiencies, 7 cyclooxygenase deficiencies and 72 von Willebrand disease. In all the patients with GT and BSS, diagnosis was confirmed with flow cytometry using multiple monoclonal antibodies to GPIIb-IIIa and GPIb-IX. There were sixty patients where initial platelet aggregation studies showed reduced (<30%) aggregation to either ADP, collagen, ristocetin or arachidonic acid in its various combination, however in 12 such patients (20%) the platelet aggregation studies were normal on repetition. All our platelet aggregation studies were done only after assuring that the patient is not taking any medicine for at least 7-10 days which may affect the platelet function tests. The present study shows that single atypically abnormal platelet aggregation studies should always be repeated. Finally in 48/217 patients (22%) some aggregation abnormality to one or more of the agonists persisted, although we could not categorize these patients into any clear-cut platelet disorder. None of these 48 patients platelet associated immunoglobulin was increased by flow cytometry. It is possible that large number of patients from that disorder will finally prove to be some form of platelet secretory defect. In north India similar group of defect in a large number of patients have been reported as isolated PF3 abnormality or thrombasthenic thrombopathy.

Adenosine Diphosphate↗
PubMed2002

Spectrum of inherited bleeding disorders from Western India.

OBJECTIVE: The study was undertaken to assess the magnitude and diversity of different bleeding disorders in Western India. MATERIALS AND METHODS: 768 cases referred to our Institute for evaluation of an underlying bleeding diathesis were investigated appropriately to detect the cause of the abnormal hemostatic function. RESULTS: 630 patients were diagnosed to have hereditary bleeding diathesis. Amongst these, 598 patients had a coagulation disorder while only 32 patients had a platelet function abnormality. Amongst the coagulation disorders, hemophilia A (70.5%) was the most common disorder followed by hemophilia B (14%) and VWD (10.8%). Glanzman's thrombasthenia (84.3%) was the most common platelet function disorder followed by Bernard-Soulier syndrome (12.5%). Some rare disorders have also been diagnosed. CONCLUSION: In spite of their apparent rarity, India has a substantial number of cases of inherited bleeding disorders. A large number of these patients is referred to many tertiary care institutions. It is therefore desirable that district hospitals must develop their laboratories to detect most of these disorders so that the patients need not travel long distances to get an appropriate diagnosis and proper management. All 1st degree female relatives of severe and moderate hemophilia must get factor assays done because some of them may be vulnerable to post-procedural or post-traumatic bleeding.

Blood Coagulation Disorders, Inherited↗
PubMed2001

Compacton solutions in a class of generalized fifth-order Korteweg-de Vries equations.

Solitons play a fundamental role in the evolution of general initial data for quasilinear dispersive partial differential equations, such as the Korteweg-de Vries (KdV), nonlinear Schrödinger, and the Kadomtsev-Petviashvili equations. These integrable equations have linear dispersion and the solitons have infinite support. We have derived and investigate a new KdV-like Hamiltonian partial differential equation from a four-parameter Lagrangian where the nonlinear dispersion gives rise to solitons with compact support (compactons). The new equation does not seem to be integrable and only mass, momentum, and energy seem to be conserved; yet, the solitons display almost the same modal decompositions and structural stability observed in integrable partial differential equations. The compactons formed from arbitrary initial data, are nonlinearly self-stabilizing, and maintain their coherence after multiple collisions. The robustness of these compactons and the inapplicability of the inverse scattering tools, that worked so well for the KdV equation, make it clear that there is a fundamental mechanism underlying the processes beyond integrability. We have found explicit formulas for multiple classes of compact traveling wave solutions. When there are more than one compacton solution for a particular set of parameters, the wider compacton is the minimum of a reduced Hamiltonian and is the only one that is stable.

Journal Article↗
PubMed2001

Monoclonal anti-acid-labile subunit oligopeptide antibodies and their use in a two-site immunoassay for ALS measurement in humans.

Quantification of the acid-labile subunit (ALS) has to date been restricted to immunoassays utilizing polyclonal antibodies. By immunization with N-terminal and C-terminal specific ALS oligopeptides, we generated monoclonal antibodies (mAbs) that target ALS-specific sequences outside the nonspecific leucine-rich repeats in the ALS molecule. For mAb selection, a special screening method was developed. Monoclonal antibody 5C9, which targets the N-terminus of ALS, is immobilized and the anti-ALS mAb 7H3, directed against the C-terminus, is biotinylated and used as tracer Ab. Due to the extreme pH-lability of ALS, changes in immunorecognition of ALS were investigated after acidification for protein unfolding in different pH ranges and in a time-dependent manner. It was determined that acidification of the serum samples to pH 2.7 for 30 min, followed by neutralization and dilution to 1:100 was the optimal acid-neutralization method. For standardization purposes, a serum pool derived from healthy volunteers was assigned the value 1 U/ml ALS. The sandwich assay has a working range with a linear dose-response curve in a log/log system between 0.005 and 10 U/ml. ALS levels in seven acromegalic patients ranged from 2.0 to 4.2 U/ml, and in 12 untreated growth hormone deficient patients from 0.036 to 0.986 U/ml (mean=0.45 U/ml). After 12 months of growth hormone therapy, ALS levels increased significantly to 1.18+/-0.45 U/ml (mean+/-SD; p<0.0006). The increase ranged from 0.48 to 1.4 U/ml. The change in ALS with growth hormone (GH) therapy correlated closer with the change in IGF-I (r=0.798, p=0.0057; Spearman rank correlation) than with the change in insulin-like growth factor binding protein (IGFBP3; r=0.549, p=0.057). This specific sandwich assay for the measurement of ALS provides a potentially valuable indicator of growth hormone secretory status. With this mAb-based immunofluorometric assay, the nonspecific detection of other proteins containing leucine-rich repeat sequences can be excluded.

Acromegaly↗
PubMed2001

Development of inhibitors in patients with haemophilia from India.

Four hundred and seven patients (352 haemophilia A and 55 haemophilia B) were investigated for the presence of factor VIII and IX inhibitors. Twenty-four out of 292 severe and two out of 36 moderate haemophilia A patients showed the presence of inhibitors. The mean age at development of inhibitors was 17.7 years (range 6-52 years). In 12 patients the inhibitors were detected due to suboptimal response to factor replacement therapy (symptomatic) and in the remaining 14 patients the inhibitors were detected during the routine screening of the patients' samples for inhibitors. They had, however, responded well to the usual doses of factor concentrates and there was no suspicion in these patients that they had developed an inhibitor (asymptomatic). There were two families in which the inhibitors were detected in more than one family member. The level of inhibitors in symptomatic patients ranged from 2.2 Bethesda units (BU) mL(-1) to 460.6 BU mL(-1), and in asymptomatic patients it ranged from 0.8 BU mL(-1) to 3.2 BU mL(-1). The inhibitors persisted in all patients except one, who developed an inhibitor postoperatively for a brief period of 3 months. All these patients were followed up from first factor exposure and were tested for inhibitors at least twice a year. The mean number of exposure days before they developed inhibitors was 47.5 exposure days (range 17-98 exposure days). No inhibitors appeared after more than 100 exposure days in any of the patients. When 50 consecutive patients were investigated for intron 22 inversions of the factor VIII gene, 17 patients were found to be positive for inversions (10 proximal inversion; seven distal inversion) out of whom four patients developed inhibitors, three patients belonging to the same family. Out of 35 haemophilia B patients, only one patient developed an inhibitor. The overall prevalence of inhibitors was thus 8.2%, which is similar to the reports from western countries, prior to the introduction of highly purified factor concentrate therapy.

Adolescent↗
PubMed2001

Venous thromboembolism in young patients from western India: a study.

The goal of this article is to study the association of known markers of thrombophilia with venous thrombosis in young patients (< 45 years) from the Western part of India. A prospective study of 432 patients (252 males and 180 females, age 1-45 years) was conducted between 1994 and 2000 (6 years). The diagnosis was confirmed in all the patients by ultrasound with Doppler or by a computed tomograph (CT) scan of the brain with or without contrast depending on the case. Detailed clinical examination, and family history was taken to establish recurrent thrombosis and familial occurrence of thrombosis. The markers studied were protein C, protein S, antithrombin (AT) III, factor V Leiden mutation, prothrombin gene G20210A polymorphism, and the thermolabile MTHFR variant C677T polymorphism, using appropriate techniques. Lupus inhibitor was tested in the first 72 patients using Dilute Russel Viper Venom Time (DRVVT) test, and anticardiolipin antibodies were tested by enzyme-linked immunosorbent assay. Protein C, protein S, and AT III deficiency was detected in 9.5%, 6.5%, and 2.6%, respectively, among the patients. Anticardiolipin antibody was present in 9.9% of the patients, whereas lupus anticoagulant was present in 8.3% of patients; factor V Leiden mutation was detected in 3% of patients; thermolabile variant of MTHFR C677T polymorphism was present in 14.9% of patients with 1.2% homozygotes. Prothrombin G20210A polymorphism was not detected in any sample in this population. One hundred and four patients of 432 (24.9%) had recurrent attacks of thrombosis without any proximate precipitating cause, whereas 7.5 % of the patients had another close member of the family with a history of deep venous thrombosis. Eighty-six members from 28 families (out of 32 families giving family history of thrombosis) were investigated and found to have protein C and protein S deficiency in seven each; factor V Leiden was present in 6, and MTHFR C677T polymorphism was present in 5 cases. Hence, 25 of 86 members (28%) from the family of patients with familial history deep venous thrombosis had positive markers for thrombophilia. Thus, we could show that in young patients presenting with thrombosis, at least 34% of them had a demonstrable cause for thrombophilia. Prothrombin gene polymorphism G20210A seems to be nonexistent in our population and AT III deficiency also appears to be low compared to other markers of thrombophilia. There is a high prevalence of variant MTHFR C677T in our series, but the incidence of MTHFR C677T in our general population is also high. Hence, the significance of this finding in our cases of deep venous thrombosis remains to be seen, but we did not see any homozygotes when we tested 70 randomly selected asymptomatic persons, whereas in the present series, 1.8% of the patients had homozygosity for the MTHFR C677T polymorphism.

Adolescent↗
PubMed2001

Transferrin is an insulin-like growth factor-binding protein-3 binding protein.

Insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) possesses both growth-inhibitory and -potentiating effects on cells that are independent of IGF action and are mediated through specific IGFBP-3 binding proteins/receptors located at the cell membrane, cytosol, or nuclear compartments and in the extracellular matrix. We have here characterized transferrin (Tf) as one of these IGFBP-3 binding proteins. Human serum was fractionated over an IGFBP-3 affinity column, and a 70-kDa protein was eluted, sequenced, and identified (through database searching and Western immunoblot) as human Tf. Tf bound IGFBP-3 but had negligible affinity to the other five IGFBPs, and iron-saturated holo-Tf bound IGFBP-3 more avidly than unsaturated Tf. Biosensor interaction analysis confirmed that this interaction is specific and sensitive, with a high association rate similar to IGF-I, and suggested that binding occurs in the vicinity of the IGFBP-3 nuclear localization site. As an independent confirmation of this interaction, using a yeast two-hybrid system, we cloned Tf from a human liver complementary DNA library as an IGFBP-3 protein partner. Tf treatment blocked IGFBP-3-induced cell proliferation in bladder smooth muscle cells, and IGFBP-3-induced apoptosis in prostate cancer cells. In summary, we have employed a combination of techniques to demonstrate that Tf specifically binds IGFBP-3, and we showed that this interaction has important physiological effects on cellular events.

Adult↗
PubMed2000

C21 steroidal glycosides from Hemidesmus indicus.

Two novel pregnane glycosides, denicunine (1) and heminine (4), have been isolated from the dried stem of Hemidesmus indicus R.Br. (family: Asclepiadaceae). Chemical transformations and spectroscopic evidence viz: 1H and 13C NMR spectroscopy and FABMS are consistent with the structures calogenin 3-O-3-O-methyl-beta-D-fucopyranosyl-(1-->4)-O-beta-D-oleandropyranosi de and calogenin 3-O-beta-D-cymaropyranosyl-(1-->4)-O-beta-D-digitoxopyranoside+ ++, respectively.

Glycosides↗
PubMed1999

A novel pentasaccharide from immunostimulant oligosaccharide fraction of buffalo milk.

A processed oligosaccharide mixture of buffalo milk induced significant stimulation of antibody, delayed-type hypersensitivity response to sheep red blood cells in BALB/c mice. This also stimulated non-specific immune response of the animals measured in terms of macrophage migration index. A novel pentasaccharide has been isolated from the oligosaccharide containing fraction having immunostimulant activity of buffalo milk. This compound was isolated by a combination of gel filtration chromatography, silica gel column chromatography of derivatised oligosaccharides while the homogeneity was confirmed by high performance liquid chromatography. The results of structural analyses, i.e. proton nuclear magnetic resonance, fast atom bombardment mass spectrometry, chemical transformations and degradations are consistent with the following structure: GlcNAcbeta(1-->3)Galbeta(1-->4)GlcNAcbeta(1-->3)Gal beta(1-->4)Glc

Adjuvants, Immunologic↗
PubMed1999

Two oligosaccharides from Marsdenia roylei.

Phytochemical analysis of dried twigs of Marsdenia roylei (family Asclepiadaceae) has resulted in the isolation of a trisaccharide, maryal, and a diglycoside, rolinose. Their structures were determined as O-beta-D-oleandropyranosyl-(1-->4)-O-beta-D-digitoxopyranosyl++ +-(1-->4)-D- cymaral and ethyl O-beta-D-oleandropyranosyl-(1-->4)-O-3-O-methyl-6-deoxy-beta-D- allopyranoside, respectively, by chemical degradation and spectroscopic methods.

Carbohydrate Conformation↗
PubMed1999

Trisaccharides from Marsdenia roylei.

The structures of two novel trisaccharides viz. royleose and deniose isolated from Marsdenia roylei were elucidated with the help of modern physico-chemical techniques and chemical transformations. They were defined as O-beta-D-oleandropyranosyl-(1-->4)-O-beta- D-cymaropyranosyl-(1-->4)-beta-D-oleandropyranose and O-beta-D-oleandropyranosyl-(1-->4)-O-beta-D-digitoxopyranosyl++ +-(1-->4)- beta-D-oleandropyranose respectively. This is the first report on the isolation of trisaccharides of rare deoxy sugars in free state from nature.

Acetylation↗
PubMed1999

Insulin-like growth factor-binding protein-3 is partially responsible for high-serum-induced apoptosis in PC-3 prostate cancer cells.

Cells are known to undergo apoptosis when cultured in high serum concentrations. However, the serum factors responsible for this induction of apoptosis have not been identified. The IGF-binding protein-3 (IGFBP-3), a negative growth regulator, is found at concentrations of 5 microgram/ml in serum. We have recently demonstrated that IGFBP-3 induces apoptosis in PC-3 cells, a prostate cancer cell line, at a concentration of 500 ng/ml. In this communication, we demonstrate the role of IGFBP-3 as one of the apoptosis-inducing agents in high serum concentrations. Treatment of PC-3 cells with increasing concentrations (40% to 90%) of intact human serum (HS) resulted in a dose-dependent decrease in cell growth. Valinomycin, an ionophore, was used as a positive control to measure the induction of apoptosis by serum treatment in PC-3 cells. Treatment with 90% serum showed significant suppression of growth (P<0.001) compared with the effect of 10% serum. Treatment with increasing concentrations of HS (40% to 90%) resulted in a dose-dependent increase in apoptosis. Treatment with 90% HS showed a 10-fold increase in apoptotic index compared with cells treated with 10% HS. Treatment of PC-3 cells with IGFs and IGFBP-3-depleted 90% human sera (depleted serum=DS) demonstrated significantly lower levels of apoptosis (50% reduction in the effect of 90% HS) suggesting a role of IGFBP-3 in inducing apoptosis in high serum concentration. Furthermore, treatment with DS supplemented with recombinant IGFBP-3 (500 ng/ml) brought the apoptotic index down close to the level of apoptosis induced by 90% intact serum treatment (P<0.001). However, DS supplemented with physiological concentrations of IGFs (500 ng/ml) showed only partial recovery of cell survival demonstrated by 90% DS. This data indicates that IGFBP-3 is one of the factors in serum that is responsible for high-serum-induced apoptosis.

Apoptosis↗