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Biomedical subjects

S Sehgal

Publications and source records attributed to S Sehgal.

At least 145 records · Page 8Linked to original sources
PubMed1990

Zoonoses in India.

Intimate and prolong contact between man and animal facilitates the transmission of various communicable diseases between them. These diseases (zoonoses) are more prevalent in developing countries especially in the rural areas. These diseases virtually stunt the economic and social growth also. Lack of authentic data and awareness regarding the occurrence of these diseases and their true impact on public health have acted as major obstacles in instituting adequate and effective control measures. The information available regarding the current status of few important zoonoses in India is being presented in this paper.

Animals↗
PubMed1990

Use of adjuvants in modulating the behaviour of Plasmodium berghei.

Different adjuvants were assessed for their role in conferring protection against the rodent malarial parasite P. berghei and compared with the classical Freund's complete adjuvant (FCA). Pretreatment of mice with trehalose dimycolate (TDM) mixed with antigen (Ag), sulpholipids (SL) mixed with Ag, muramyl dipeptide (MDP) alone, liposomes containing Ag and phosphomannoinositides (PIM) mixed with Ag were ineffective in conferring protection. However, MDP given with squalane (Sq) and Ag, MDP with incomplete Freund's adjuvant (IFA) and Ag, palmitoyl-MDP with Sq and Ag, aluminium hydroxide adsorbed Ag, and FCA with Ag were effective in conferring varying degrees of protection to mice. Complete protection in rats was obtained with MDP mixed with Sq and Ag, and FCA mixed with Ag, and a partial protection with liposomes containing Ag.

Adjuvants, Immunologic↗
PubMed1990

Immunoelectrophoresis of mycobacterial antigens.

Polyvalent antiserum to culture filtrate of H37 Ra M. tuberculosis was raised in rabbits. Monospecific antiserum was raised against M. tuberculosis antigen-5, prepared from the culture filtrates by immunoabsorbent affinity chromatography. On immunoelectrophoresis, antigen-5 demonstrated single precipitin arc against polyvalent and monospecific antisera. The culture filtrate antigen demonstrated multiple precipitin arcs against polyvalent antiserum and single precipitin are against monospecific antiserum. Antigen-5 could be isolated and characterized from the culture filtrate of H37 Ra M. tuberculosis. Immunoelectrophoresis could be one of the method to characterize the mycobacterial antigens prepared in the laboratory.

Animals↗
PubMed1990

IgG antibody to Mycobacterium tuberculosis antigen-5 in cerebrospinal fluid and its diagnostic application in tuberculous meningitis.

IgG antibody to M. tuberculosis antigen-5 was detected by non-competitive ELISA in cerebrospinal fluid specimens (CSF), from 40 patients with clinical diagnosis of tuberculous meningitis and in 42 patients of non-tuberculous neurological diseases. The geometric mean antibody titer in CSF specimen for tuberculous and non-tuberculous groups were 156 and 8 respectively. The antibody titer in CSF specimens showed no correlation to IgG levels, tuberculin reactor status and duration of chemotherapy in patients with tuberculous meningitis. At a dilution end-point 1:40, the assay had a sensitivity of 84% and specificity of 92%. However at dilution end-point 1:80, the specificity of the assay could be increased to 100% but sensitivity of the assay decreased to 75%. IgG antibody detection against M. tuberculosis antigen-5 by non-competitive ELISA, described in this communication has potential application in the laboratory diagnosis of tuberculous meningitis, particularly in developing countries where the incidence and prevalence of tuberculous meningitis is still high. In culture-negative cases of tuberculous meningitis, non-competitive ELISA could be applied as an alternative diagnostic tool.

Antibodies, Bacterial↗
PubMed1990

ELISA of IgG antibody to Mycobacterium tuberculosis antigen-5, PPD in CSF in tuberculous meningitis patients.

IgG antibody to M. tuberculosis antigen-5 and tuberculin purified protein derivative (PPD) was measured by enzyme linked immunosorbent assay (ELISA) in cerebrospinal fluid (CSF) specimens of 55 patients with tuberculous meningitis (TBM) and 55 patients with non-tuberculous neurological diseases (control group). The geometric mean antibody titre in CSF specimens of TBM patients was 82.4 with antigen-5 and 96.5 with PPD. In the control group, the geometric mean antibody titres for these antigens in CSF specimens were 4.6 and 10.8 respectively. The antibody titres did not show any correlation with tuberculin reactor status, duration of chemotherapy and IgG levels in CSF specimens in patients with TBM. At dilution end point 1:80, specificity of the assay was 100 per cent with antigen-5 and sensitivity of the assay was 70.9 per cent. False positivity observed in the control group with PPD antigen could be eliminated in 1:80 dilution in the assay with antigen-5. Antigen-5 is more specific than PPD antigen for the diagnosis of tuberculous meningitis.

Antibodies, Bacterial↗
PubMed1990

Non-organ specific & organ specific antibodies in rheumatoid arthritis.

Fifty patients of rheumatoid arthritis clinically diagnosed (by ARA criteria) were studied for both non-organ specific [rheumatoid factor (RF), anti-nuclear antibodies (ANA), extractable nuclear antibody (ENA), granulocyte specific anti-nuclear antibody (GS-ANA), anti-smooth muscle antibody (SMA) and anti-mitochondrial antibody (AMA)] and organ specific, [anti-adrenal (AAA), anti-islet cell (ICA), antithyroid antibody (ATA) and anti-parietal cell (PCA)] auto antibodies. RF was positive in 80 per cent of patients. ANA was positive in 44 per cent of patients, ENA in 62 per cent, SMA in 20 per cent, AMA in 18 per cent and GS-ANA in 68 per cent. Of the organ specific antibodies, PCA was demonstrable in 28 per cent of the patients and none of the other antibodies were present. Circumstantial evidence indicates that ANA and GS-ANA are not synonymous but independent, cross-reacting entities and the presence of both increase the sensitivity (94%) of diagnosis of RA.

Adolescent↗
PubMed1990

Cholera outbreak in Delhi--1988.

Delhi experienced an outbreak of cholera during July-August 1988 which affected residents from all walks of life. A total of 1824 laboratory confirmed cholera cases were detected in two months period at I.D. Hospital, Delhi alone. The number of cholera cases in July-August 1988 was 5-10 times that of the same period during the previous years in the Capital. The outbreak was caused by Vibrio cholerae Ogawa biotype ElTor. Majority of the laboratory confirmed cases (about 74 per cent) were seen in children under the age of 15 years. Though the cases were spread all over Delhi, almost three-fourths of total cases were reported from two specific zones (Shahdara and Civil Lines). Most of the isolates were sensitive to all antibiotics tested. The proportion of isolates resistant to furazolidone during this outbreak was substantially higher than in previous years suggesting that the outbreak may have been caused by the introduction of a new strain rather than proliferation of endemic strain. The salient features of the outbreak are discussed.

Adolescent↗
PubMed1990

Antigenic analysis of Cysticercus cellulosae by crossed immunoelectrophoresis & its role in immune diagnosis of neurocysticercosis.

The antigenic composition of Cysticercus cellulosae cysts excised from infected pig and autopsied human brain was analysed by crossed immunoelectrophoresis with an intermediate gel technique using rabbit hyperimmune serum. Normal pork muscle and human brain antigen were used to differentiate parasite derived components from that of host. Attempts were made to look for the rich source of parasitic immunodominant antigens by analysing preparations of different parts of cyst namely scolex and fluid using rabbit hyperimmune serum. Twenty three antigenic components were identified in sonicate extract of porcine cyst, of which 15 were parasite derived. On comparison with antigens of whole cyst sonicate, scolex showed 10, cyst fluid 9 and human cyst sonicate 11 parasite derived antigens. Serum and cerebrospinal fluid (CSF) of neurocysticercotic patients reacted with 12 parasite derived antigens of porcine cyst sonicate (PCS) in a heterogenous manner. It was also noticed that human cyst sonicate (HCS) lacked 4 of the parasite derived antigens present in the PCS.

Animals↗
PubMed1990

Sero-epidemiology of subacute sclerosing panencephalitis in Delhi.

Between 1986 and early 1989, 47 patients of subacute sclerosing panencephalitis (SSPE) were referred to the National Institute of Communicable Diseases, Delhi from different hospitals of Delhi. They were 40 (87%) males and 7 (13%) females. The age at onset of illness ranged from 4 to 18 yr. Thirty (63.9%) patients gave history of measles attack in the first two years of life. All but one patient gave a past history of measles attack. Only one patient gave history of measles immunization. The titres of haemagglutination inhibiting antibodies to measles virus in serum in SSPE patients ranged from 1:8 to 1:2048 and in CSF from 1:4 to 1:256, while in control group, it ranged from 1:2 to 1:128 in serum and nil to 1:2 in CSF. The geometric means of haemagglutination inhibiting antibodies in serum and CSF of SSPE patients were 10 and 15 times higher than in the control group.

Adolescent↗
PubMed1990

Auto-antibody profile in systemic lupus erythematosus.

Thirty cases of systemic lupus erythematosus (SLE) were selected on the basis of revised ARA criteria (American Rheumatology Association) and their sera examined for the presence of various auto-antibodies. The male to female ratio was 1:5 and joint manifestations were the commonest mode of presentation. The frequency of various manifestations was found to differ between the two sexes. Renal lesions were observed in 9 (nine) cases. ANF was detected in 28 of the 30 cases and the diffuse pattern was the commonest (11 cases) (37.7%). Six cases had very high titres (a titre of more than 1:1280) of antinuclear factor. Antibodies to DNA were detected in 9 cases (30%). These patients tended to have more severe disease, with high titres of ANF and low complement levels. Presence of antibodies to DNA, however, could not be correlated with the severity of renal lesions. Anti Sm antibody was found in 8 cases (26.7%), anti nRNP antibody in 19 cases (63.3%) and antihistone antibodies in 22 cases (73.3%). Patients harbouring any of these three antibodies tended to have a milder clinical disease.

Antibodies, Antinuclear↗
PubMed1989

Enhancement of the antigen-binding capacity of incomplete IgG antibodies to Brucella melitensis through Fc region interactions with staphylococcal protein A.

Incomplete IgG anti-Brucella antibodies in human sera were detected using both a conventional ELISA and a modified method. In the ELISA procedure serum IgG was allowed to bind solid-phase B. melitensis antigen and, after washing, biotinylated staphylococcal protein A (BioSPA) was used as an Fc-specific tracer followed by streptavidin-HRP conjugate. In the modified method, serum IgG was co-incubated with a defined quantity of BioSPA in the presence of solid-phase antigen. BioSPA bound Fc regions of serum IgG irrespective of antigen specificity whilst antibodies which were specific for Brucella bound the solid-phase antigen through their Fab regions and were detected subsequently by streptavidin-HRP. IgG anti-Brucella antibodies were detectable with a 5-25-fold increase in sensitivity when they were thus 'activated' in situ with BioSPA. In contrast with the IgG antibodies of untreated human sera, BioSPA-activated IgG showed strong antigen binding capacity and resisted the dissociation effect of the chaotropic agent, guanidine hydrochloride. In similar experiments, BioSPA did not enhance the affinity of IgG anti-Salmonella antibodies of human sera towards S. typhi antigen. The activating effect of BioSPA on the incomplete IgG anti-Brucella antibodies from patients with brucellosis possibly involves a re-orientation of Fab sites.

Antibodies, Bacterial↗
PubMed1989

Necessity of adjuvants for inducing effective antibody response to zona pellucida antigens.

Rhesus monkeys evoked a vigorous antibody response to a single heteroimmunization dose of zona pellucida antigens, when these were administered along with complete Freund's adjuvant. The antisera recognized all the three major porcine zona glycoprotein families and the animals were rendered amenorrheic after such immunization. Monkeys immunized with zona without adjuvant, however, failed to show any anti-zona antibody response and had normal menstrual cycles. Zona pellucida glycoproteins are thus not effective immunogens unless administered along with a powerful adjuvant.

Adjuvants, Immunologic↗
PubMed1989

Receptor-mediated drug delivery to macrophages in chemotherapy of leishmaniasis.

Methotrexate coupled to maleylated bovine serum albumin was taken up efficiently through the "scavenger" receptors present on macrophages and led to selective killing of intracellular Leishmania mexicana amazonensis amastigotes in cultured hamster peritoneal macrophages. The drug conjugate was nearly 100 times as effective as free methotrexate in eliminating the intracellular parasites. Furthermore, in a model of experimental cutaneous leishmaniasis in hamsters, the drug conjugate brought about more than 90% reduction in the size of footpad lesions within 11 days. In contrast, the free drug at a similar concentration did not significantly affect lesion size. These studies demonstrate the potential of receptor-mediated drug delivery in the therapy of macrophage-associated diseases.

Albumins↗
PubMed1989

Identification of major antigens of Leishmania donovani using kala azar sera.

The study was conducted with the prime objective of isolating an antigen from the crude preparation of whole promastigotes (Leishmania donovani) with a view to future exploitation in serodiagnosis and production of monoclonal antibodies. Soluble antigen, prepared from promastigotes isolated from actively growing cultures, was fractionated by gel filtration chromatography over a column of Sephadex G200. Three peaks of proteins could be recovered. The antigenic reactivity of different fractions was checked against sera of kala azar patients by immunoelectrophoresis (IEP), rocket immunoelectrophoresis (RIEP) and enzyme-linked immunosorbent assay (ELISA). The first peak was found to be highly reactive in comparison with other peaks. SDS-PAGE and western blot analysis of this antigen revealed a major antigen of promastigotes in the vicinity of 65 to 66 kDa, while a weakly reactive triplet could also be detected in the low molecular weight region.

Animals↗
PubMed1989

Long-term effects of immunization with porcine zona pellucida on rabbit ovaries.

Groups of rabbits were immunized with 4 doses of porcine zona pellucida antigen along with different adjuvants. The presence of antibody after immunization was checked periodically using different assay systems. The impact of immunization on ovaries was evaluated at different time intervals up to 2 years. Results of the study showed generation of high titre antibodies which could be detected until the end of the period of observation. The antibodies specifically bound to zona pellucida in situ were demonstrated by immunoperoxidase staining, and in vitro by inhibition of enzymatic digestion of zonae. Histologically, antibodies had numerous pathological effects on ovaries including thinning of the cortex, aberrant cell clusters, stromal cell hyperplasia, perifollicular fibrosis, irregular zona formation and arrest of follicle development. These changes could be correlated with the length of exposure to antibodies. It is concluded that heat-solubilized porcine zona (HSPZ) protein is a very strong immunogen and causes infertility by arresting the maturation of developing follicles. There is a need to identify the sperm receptor so that immunization could selectively impair sperm-egg interaction.

Animals↗