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Biomedical subjects

D Sinha

Publications and source records attributed to D Sinha.

83 records · Page 5Linked to original sources

Investigation on interaction of Achatinin, a 9-O-acetyl sialic acid-binding lectin, with lipopolysaccharide in the innate immunity of Achatina fulica snails.

Achatinin, a 9-O-acetyl sialic acid (9-O-AcSA) binding lectin, has been demonstrated to be synthesized in amoebocytes of Achatina fulica snails. This lectin was affinity-purified from Achatina amoebocytes lysate (AAL); it appeared as a single band on native polyacrylamide gel electrophoresis (PAGE) and showed 16 identical subunits of M.W. 15 kDa on sodium dodecyl sulphate (SDS)-PAGE. It was found to be homologous with an earlier reported lectin, Achatinin-H, derived from hemolymph of A. fulica snails (Sen, G., Mandal, C., 1995. The specificity of the binding site of Achatinin-H, a sialic-acid binding lectin from Achantia fulica. Carbohydr. Res., 268, 115-125). Homology between both lectins was confirmed by their similar electrophoretic mobilities, carbohydrate specificity and cross reactivity on immunodiffusion. Achatinin showed in vitro calcium dependent binding to two 9-O-acetylated sialoglyoconjugates (9-O-AcSG) on lipopolysaccharide (LPS) (Escherichia coli 055: B5) of M.W. 40 kDa and 27.5 kDa, which was abolished following de-O-acetylation. Based on the previously defined narrow sugar specificity of Achatinin towards 9-O-AcSAalpha2-->6GalNAc [Sen, G., Mandal, C., 1995. The specificity of the binding site of Achatinin-H, a sialic-acid binding lectin from Achatina fulica. Carbohydr. Res., 268, 115-125], we conclude that LPS contains this lectinogenic epitope at the terminal sugar moiety. The Achatinin-mediated hemagglutination inhibition of rabbit erythrocytes by LPS further confirmed it. The lectin exhibited bacteriostatic effect on Gram-negative bacteria E. coli, DH5alpha and C600. AAL was earlier reported to undergo coagulation in presence of pg level of LPS (Biswas, C., Mandal, C., 1999. The role of amoebocytes in the endotoxin-mediated coagulation in the innate immunity of Achatina fulica snail, Scand. J. Immunol. 49, 131-138). We now demonstrate that Achatinin participates in LPS-mediated coagulation of AAL as indicated by enhanced release of Achatinin from the LPS stimulated amoebocytes and most importantly, by exhibiting a 77% decline in the coagulation of AAL when depleted of Achatinin. Level of Achatinin sharply declined (17-fold) following injection of LPS (20 microg per snail) to the snails, which was reversible by simultaneous injection of LPS and leupeptin implying the presence of LPS-mediated serine protease activity in Achatinin. This was substantiated when purified Achatinin in vitro showed serine protease activity in the presence of LPS followed by its complete blockage in the presence of leupeptin and phenyl methyl sulphonyl fluoride. Therefore, Achatinin, an abundantly available lectin at multiple sites of A. fulica, by virtue of its interaction with LPS, essentially plays a crucial role in the innate immune protection of A. fulica snails.

Animals↗

Complementary and alternative medicine use in children with attention deficit hyperactivity disorder.

OBJECTIVES: The use of complementary and alternative medicines (CAM) is increasing in the general population. Attention deficit hyperactivity disorder (ADHD) is a chronic condition that has a major impact on children's functioning and has no cure, therefore many families may try CAM at some stage. We aimed to determine (i) the lifetime incidence of CAM use in a clinical sample of children with ADHD; (ii) parents' perceptions of the effectiveness of CAM for ADHD; and (iii) the proportion who informed their paediatrician. METHODS: The sample was drawn from patients aged 5-17 years with ADHD attending Royal Children's Hospital, Melbourne outpatient clinics from May to September 2003. A 20-item survey was posted to consenting families. RESULTS: From 105 surveys, 75 were returned (response rate 71.4%). Mean child age was 11.1 (SD 2.9, range 5.0-16.9) years; 65 (86.7%) were boys. Fifty (67.6%) families reported current or past CAM use. Of the 23 different therapies reported, the most common were modified diet (33 families), vitamins and/or minerals (16), dietary supplements (12), aromatherapy (12) and chiropractics (10). Reported effectiveness was variable. The factors most frequently rated as important in choosing CAM were minimizing symptoms (40 families), adding to the benefit of conventional treatment (30) and avoiding side-effects (29). Thirty-two (64%) of 50 families reported that they informed their paediatrician of their CAM use. CONCLUSION: Complementary and alternative medicines are commonly used in children with ADHD. Paediatricians should inquire about the use of CAM, and use available resources to help guide families in their therapeutic choices.

Adolescent↗

Risk factors and their implication on silent myocardial ischaemia.

Sixty-five cases were evaluated for silent myocardial ischaemia (SMI) by computerised treadmill test (TMT) and ambulatory electrocardiographic monitoring (AEM). There were 59 males and 6 females. The cases were divided into GP-I-stable angina (35 cases) GP-II-stable angina after myocardial infarction (15 cases) and GP-III-asymptomatic (15 cases). Age in each group ranged from 36 years to 62 years (GP-I), 40 years to 68 years (GP-II) and 36 years to 48 years (GP-III). Conventional risk factors viz. hypertension, diabetes mellitus, hyperlipidemia, smoking and family history were assessed with a view to see their implication on SMI. 43 patients (62.2%) were found to have SMI including mixed episodes. Out of these 43, TMT was positive in 29 patients (67.4%), AEM was positive in 41 patients (95.3%) and both TMT and AEM were positive in 27 patients (62.7%). Correlative analysis between risk factors and SMI revealed that higher number of was associated with not only more positive TMT and AEM test along with increased episodes of SMI but also increased degree of ST-T depression. It was also found that AEM is more sensitive than TMT (80% Vs 48%) for diagnosing SMI (SED = 9.03%), though specificity of the tests is same (93.3%).

Adult↗

Pacing in children and adolescents.

Sixty patients aged 5-16 years underwent implantation of permanent pacemaker and were followed up for 3-11 years. All these patients presented with syncope or symptomatic bradyarrhythmias; two also had congestive cardiac failure in addition, which was ameliorated by pacemaker implantation. A majority of the patients (48) had congenital complete heart block. 8 patients presented with sick sinus syndrome; 4 patients presented with post operative chronic complete heart block. Transvenous endocardial electrode was used in 54 cases and epicardial pacing was done in 6 cases. A majority (55) of the patients received VVI pacemakers; AV sequential pacemakers were implanted in 5 cases. On follow up, the children returned to normal activity and their psychological well being was striking. Reoperation had to be done in 35 cases, a majority being due to over stretching of electrodes (15) and battery exhaustion (12). Two patients died, one due to bacterial endocarditis and the other succumbed to sudden death during vigorous physical activity. Major problems of pacing in children are that veins are often too thin and delicate for electrode insertion, and of the child's growth that stretches the lead system. The problems of pulse generator size and longevity have been partly overcome by introduction of newer models that are small and programmable.

Adolescent↗

O-acetyl sialic acid binding lectin as a probe for detection of subtle change on cell surface induced during acute lymphoblastic leukemia (ALL) and its clinical application.

A novel probe, a 9-O-acetylated sialic acid binding lectin, namely achatininH (ATNH) has been used for the detection of changes on the cell surface during acute lymphoblastic leukemia (ALL). ATNH does not agglutinate normal human erythrocytes, however it is capable of agglutinating erythrocytes and peripheral blood mononuclear cells (PBMC) of patients suffering from ALL. The differential expression of a key receptor, 9-O-acetylated sialo glyco conjugate (9-O-AcSG), on PBMC was observed using a simple lymphoproliferative assay (LA). The extent of expression of 9-O-AcSG was used as an index to distinguish ALL patients of different clinical stages and assess the probability of relapse. The amount of ATNH needed for maximum stimulation served as a tool to indirectly measure the extent of expression of 9-O-AcSG on PBMC surface. The acetylated sialo glycoconjugate was expressed at a very high concentration during acute phase of the disease. Subsequently it decreased during treatment persisted during maintenance therapy and reappeared with relapse. PBMC of normal human donors required 80 times more ATNH in comparison to the untreated acute phase ALL patients. No cross reactivity was found in non Hodgkin's lymphoma, chronic myelogenous leukemia and thalassaemia patients.

Agglutination Tests↗

Hepatitis B virus transmission in an elementary school setting.

CONTEXT: The risk of transmission of hepatitis B virus (HBV) in day care centers and schools is low. OBJECTIVE: To investigate the source of HBV transmission for an elementary school teacher with acute hepatitis B. DESIGN: Serologic survey for HBV infection among elementary school students, school staff, and household members of an HBV-infected teacher and student. SETTING: General community and elementary school. PATIENTS: Elementary school students and staff members and household members of an HBV-infected teacher. MAIN OUTCOME MEASURES: Elementary school students, school staff, and household members of an HBV-infected teacher were tested for markers of HBV infection. Samples positive for hepatitis B surface antigen (HBsAg) were tested for HBsAg subtype using monoclonal antibodies and examined for HBV DNA homology by polymerase chain reaction techniques. RESULTS: An HBV-infected student and the teacher were found to have the same HBV subtype (ayw1-2) and to have identical HBV DNA sequences. The teacher reported none of the usual risk factors for acquiring HBV infection, and none of her family members had been infected prior to her illness. The specific means of HBV transmission from student to teacher was not identified. Of 108 total children in the same grade as the HBV-infected student, 102 (94%) were tested for serologic markers of HBV infection, and none was positive. CONCLUSIONS: This investigation documented transmission from an HBV-infected student to a teacher in an elementary school setting without a reported overt percutaneous or permucosal exposure to blood or infectious body fluids. Transmission of HBV to other students or staff members in the school was not observed.

Acute Disease↗