Biomedical subjects

V Sivanandan

Publications and source records attributed to V Sivanandan.

At least 19 recordsLinked to original sources

PubMed1992

Enhancement of antibody response of turkeys to trivalent avian influenza vaccine by positively charged liposomal avridine adjuvant.

Trivalent avian influenza (AIV) antigens (H4N8, H5N2 and H7N3), mixed with positively charged, negatively charged and neutral avridine-containing liposomes, and oil-emulsion were subcutaneously administered to 6-week-old turkeys. Charged liposomal avridine adjuvant, either positive or negative, produced a better antibody response than uncharged liposomal avridine or oil-emulsion adjuvants when used in a trivalent avian influenza vaccine. The antibody response to the different antigens was generally greater to the positively charged adjuvanted vaccine compared with the negatively or neutral charged or oil-emulsion adjuvanted vaccines and these differences were significant (P less than 0.05) with the three antigens. The results suggest that the positively charged liposomal avridine plays a significant role as adjuvant to the AIV antigens.

Adjuvants, Immunologic↗

PubMed1991

A quantitative measurement of the effect of avian influenza virus on the ability of turkeys to eliminate Pasteurella multocida from the respiratory tract.

The effect of avian influenza virus (AIV) infection on the ability of turkeys to eliminate Pasteurella multocida from the respiratory tract was evaluated. Four-week-old turkeys were experimentally infected with an apathogenic AIV subtype (H5N2) by the oculonasal route and subsequently superinfected with P multocida (Urbach strain) by the intranasal route three days after infection with AIV. Quantitative clearance of P multocida from the trachea and lung was determined using a pour plate technique on samples collected at intervals after infection. Samples from turkeys which had been infected with AIV were found to yield more P multocida than those from turkeys which had not been infected with AIV. The numbers of P multocida increased in infected birds to a greater extent than in birds which had not been infected with the virus. The present study suggests that AIV infection may contribute to the increased numbers and a decreased clearance of P multocida in turkeys.

Animals↗

PubMed1991

Identification and characterization of viral polypeptides from type-II avian adenoviruses.

The polypeptides of serologically related viruses of hemorrhagic enteritis (HE) in turkeys, marble spleen disease (MSD) in pheasants, and splenomegaly in chickens (SMC) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analyzed by protein immunoblotting with polyclonal antibodies to HE virus (HEV). The viral polypeptides II, III, IV, V, VI, and VII were detected on SDS-PAGE with the size range from 18 to 97 kDa in HEV. Viral polypeptides II, III, V, VI, and VII were detected in MSD virus and virus of SMC. Protein immunoblotting of viral proteins with anti-HEV serum revealed antigenic differences between the 3 viruses of avian adenovirus type-II examined. The differences were that the polypeptides II, III, IV, V, VI, and VII were identified in HEV and the polypeptides II, V, VI, and VII were identified in MSD virus and virus of SMC. The bands of penton base (polypeptide III) and fiber (polypeptide IV) were seen in HEV only by protein immunoblotting.

Adenoviridae Infections↗

PubMed1991

Decrease in pulmonary artery pressure with slow release nifedipine in Saudi patients with primary pulmonary hypertension.

We studied the acute and short-term hemodynamic effects of vasodilators in three Saudi patients with primary pulmonary hypertension. The study protocol included the measurement of pulmonary artery pressure, resistance and cardiac output at baseline and at 15, 30, 45 and 60 minutes after 10 mg sublingual nifedipine. These hemodynamic studies repeated at 3 and 6 months follow-up. A 24 hour profile of pulmonary artery and aortic pressures were recorded to evaluate the effect of 20 mg of slow release nifedipine, after 25 mg of captopril and 5 mg of sublingual isordil. After nifedipine there was a marked reduction in systolic pulmonary artery pressure from 85 +/- 18 to 55 +/- 8 mmHg and the pulmonary resistance decreased from 1422 +/- 367 to 954 +/- 69 dynes-sec/cm-5. The cardiac output increased from 2.9 +/- 0.2 to 0.2 to 4.0 +/- 0.4 l/min after nifedipine. The patients were discharged on nifedipine 10 mg qid, except for patient #3 who was a non-responder. At follow-up there was a symptomatic improvement and a favourable hemodynamic response was maintained, though patient #2 required a higher dose of nifedipine. The pulmonary artery 24 hour pressure profile revealed that 20 mg slow release adalat reduced pulmonary artery pressure for a 6 hour period. Whereas, regular nifedipine decreased pulmonary artery pressure for a period of less than 90 minutes. There was no favourable hemodynamic response to either captopril 25 mg oral of isordil 5 mg administered sublingually. We conclude that slow release nifedipine decreases the pulmonary artery pressure for longer periods compared to regular nifedipine in patients with primary pulmonary hypertension.

Adolescent↗

PubMed1988

Efficacy of infectious bronchitis virus vaccines against heterologous challenge.

Twenty-four-week-old white Leghorn layers were inoculated subcutaneously with a killed Newcastle disease-infectious bronchitis (Massachusetts type) virus (MIBV) vaccine. Twenty-eight weeks after vaccination, the birds were challenged intraocularly with the Arkansas strain of infectious bronchitis virus (AIBV) to determine the effects of heterologous virus exposure on egg production, egg quality and serum antibody response of the birds. The challenged hens laid significantly (P less than 0.005) fewer eggs than the unchallenged layers. Eggs laid by the unchallenged groups weighed significantly more (P less than 0.005) than those laid by the challenged groups. Further, the internal quality (Haugh units) and shell quality of eggs laid by the AIBV-challenged hens was significantly (P less than 0.005) inferior to those from the unchallenged hens. In addition, the AIBV-challenged hens laid more soft-shell, misshapen and small eggs than the unchallenged hens. The Arkansas serum haemagglutination inhibition (AIBV-HI) titres of AIBV challenged birds increased up to four weeks after challenge. The corresponding MIBV haemagglutination-inhibition (MIBV-HI) titres decreased during the same period. The study indicates that killed MIBV vaccine offered no protection to birds exposed to heterologous AIBV.

Animals↗

PubMed1986

Siderophore production by Pasteurella multocida.

Pasteurella multocida grown under conditions of iron deprivation secreted into the culture medium a growth-enhancing factor which functioned as a siderophore. The siderophore was found to be neither a phenolate nor a hydroxamate by chemical tests and bioassays and was given the trivial name multocidin. Multocidin was partially purified and found to be a highly polar, nonaromatic, and dialyzable compound. This is the first report demonstrating the production of a siderophore by P. multocida.

Culture Media↗

PubMed1986

Standardization of enzyme-linked immunosorbent assay for avian influenza virus antibodies in turkeys.

The signal-to-noise ratio was useful in determining the optimal dilution of rabbit anti-turkey conjugate. Optimum dilution for rabbit anti-turkey conjugate to be used in the enzyme-linked immunosorbent assay (ELISA) was 1:1,000. The avian influenza virus antigen concentration was 128 hemagglutinating units (0.3 microgram of protein) per well, as determined by checkerboard titration. Bovine serum albumin fraction V increased nonspecific binding of conjugate and was not used to coat the plates in subsequent tests. Using ELISA, nonspecific binding to avian influenza virus-coated plates were not found with antibodies to Newcastle disease virus, infectious bursal disease, Salmonella, or Escherichia coli. Chromogens o-phenenediamine, and 2,2'-azino-di-(3-ethyl-benz-thiazoline sulfonic acid) were almost equal in sensitivity for detecting released oxygen from the H2O2. The substrate plate was more sensitive than was the polystyrene plate. Dual wavelength was reliable in reading ELISA results.

Animals↗

PubMed1985

Field trials to test the efficacy of polyvalent Marek's disease vaccines in layer and broiler breeder chickens.

As a follow-up to earlier trials to evaluate the efficacy of polyvalent Marek's disease (MD) vaccines in broilers, four trials were conducted with layer or broiler breeder flocks. Chickens caccinated with trivalent (Md11/75C plus SB-1 plus HVT) and bivalent (SB-1 plus HVT) vaccines were compared with those vaccinated with turkey herpesvirus (HVT) alone. Data from three of the four trials indicated polyvalent vaccines were more efficacious than HVT. However, critical interpretations were confounded by low MD lesion frequencies, unequal exposure in different houses on a farm, and difficulty in the differential diagnosis of mortality due to neoplasms. The data confirmed our earlier observation that trivalent and bivalent vaccines were equally effective. Broiler progeny of breeders vaccinated or contact-infected with Serotype 2 MD virus were well protected by either bivalent or HVT vaccines against challenge with very virulent MD virus strains in the laboratory. A high incidence of lymphoid leukosis was observed in two trials and may have been due to post-hatch exposure to an unidentified environmental source of avian leukosis virus.

Animals↗

PubMed1978

Immunocompetent cells of the turkey: age and organ distribution patterns of T and B lymphoid cells.

The percentage of lymphoid cells from the bursa of Fabricius, thymus, spleen, peripheral blood, and cecal tonsils reactin with chicken antisera to turkey bursa and thymus were evaluated, using 1-day-old to 5-week-old turkeys. For this, rabbit anti-chicken globulin fluorescein isothiocyanate conjugate was used. The percentage of lymphoid cells showing immunoglobulin surface determinants from these organs also was examined, using a direct immunofluorescence test with a rabbit anti-turkey globulin fluorescein isothiocyanate conjugate. This study suggests that the bursa-specific antigen and immunoglobulin surface determinants could be used as markers for bursa-derived cells in the turkey. It also was found that thymus-specific antigen could be used as a marker for thymus-derived cells.

Age Factors↗

PubMed1976

Immunocompetent cells of the turkey: antigenic surface determinants of turkey lymphoid cells.

The serologic properties of chicken antiserums to turkey bursa and thymus were assayed by the cytotoxicity tests and indirect immunofluorescence. The following antigenic surface determinants were detected, using proper absorptions on thymic and bursal lymphoic cells: (a) common lymphocyte antigens present on both kinds of cells, (b) thymus-specific antigens, (c) bursa-specific antigens, and (d) immunoglobulin surface determinants in bursa cells, as revealed by direct immunofluorescence.

Animals↗

PubMedDate not supplied

Influenza in commercial broiler breeders.

Influenza was detected in a flock of broiler breeders during routine serological monitoring. Although there were no clinical signs, egg production may have been affected in hens on one story of a two-story breeder house. Intensive measures were taken to avoid transmission to other farms. Two months after the flock was found to be serologically positive, sentinel hens were placed in the flock, and they became serologically positive 1 month later. In spite of this evidence for virus being present in the flock, no detectable transmission to any other farm occurred.

Animals↗

PubMedDate not supplied

Serological response in broiler chicks to different commercial Newcastle disease and infectious bronchitis vaccines.

Broiler chicks were administered vaccines against Newcastle disease and infectious bronchitis (both Arkansas and Massachusetts strains) at 2 weeks of age as either primary or secondary vaccinations. The vaccine was administered as a spray at 2 weeks of age to chicks that had received Newcastle disease vaccine alone, bronchitis vaccine alone, both vaccines in combination, or no vaccine at day 1 in the hatchery. The Newcastle disease hemagglutination-inhibition response was significantly lower in chicks receiving Newcastle disease vaccine as a secondary vaccine at 2 weeks than in those receiving the vaccine as a primary vaccination at that age. In contrast, the bronchitis hemagglutination-inhibition response was significantly higher in chicks receiving bronchitis vaccine as a secondary vaccination at 2 weeks than in those receiving the vaccine as a primary vaccination at that age.

Administration, Inhalation↗

PubMedDate not supplied

Endotoxin lipopolysaccharide from Escherichia coli and its effects on the phagocytic function of systemic and pulmonary macrophages in turkeys.

The effect of Escherichia coli lipopolysaccharide (LPS) on the competence of pulmonary macrophages and phagocytic cells from the systemic circulation of turkeys was examined using luminol-enhanced zymosan-stimulated chemiluminescence. The results showed a rapid and accelerated oxidative burst in both systemic and pulmonary macrophages in LPS-treated turkeys that was significantly greater than in untreated controls. However, this increased oxidative metabolism induced by LPS was not associated with enhanced intracellular bacterial killing by pulmonary macrophages. Turkeys treated with LPS showed a highly significant decrease in pulmonary bactericidal activity against Staphylococcus aureus challenge, indicating a defect in pulmonary macrophage function induced by LPS.

Animals↗

PubMedDate not supplied

Isolation of H13N2 influenza A virus from turkeys and surface water.

This is the first report of the isolation of H13N2 avian influenza virus (AIV) subtype from domestic turkeys. This subtype was also isolated from nearby surface water. The observation of large numbers of gulls in close association with turkeys on range before the virus isolations suggests that this virus subtype was transmitted from gulls to range turkeys. Turkey flocks infected by this virus subtype did not show any clinical signs of the disease, although seroconversion did occur. The H13N2 isolates were found to be non-pathogenic in chickens.

Animals↗

PubMedDate not supplied

A broad-spectrum avian influenza subtype antigen for indirect enzyme-linked immunosorbent assay.

A broad-spectrum viral antigen for the detection of avian-influenza-virus-specific antibodies, using the indirect enzyme-linked immunosorbent assay (ELISA), was identified. Purified and disrupted antigens were used, which helped to increase the sensitivity of the assay. All of the antigens tested were able to detect antibodies to homologous and heterologous viruses to varying degrees. The H9N2 antigen was the best single antigen to use in the ELISA to screen for avian influenza virus antibodies. It detected antibodies against six viruses as early as day 4 postinfection.

Animals↗

PubMedDate not supplied

Effects of avian infectious bronchitis virus (Arkansas strain) on vaccinated laying chickens.

Twenty-four-week-old white leghorn layers were inoculated subcutaneously with a killed Newcastle-infectious bronchitis (Massachusetts type) virus (MIBV) vaccine. The birds were challenged 194 days later intraocularly with Arkansas strain of infectious bronchitis virus (AIBV). The challenged hens laid significantly (P less than 0.005) fewer eggs than the unchallenged layers, and the eggs laid by the challenged groups weighed significantly less (P less than 0.001) than those laid by the unchallenged groups. Further, the internal quality (Haugh units) and shell quality of eggs laid by the challenged hens were significantly (P less than 0.005) inferior to the quality of eggs from unchallenged hens, and the challenged hens laid more soft-shelled, misshapen, and small-sized eggs than the unchallenged hens. The Arkansas serum hemagglutination-inhibition (AIBV-HI) titers of challenged birds increased continuously through 29 days post-challenge. The MIBV hemagglutination-inhibition (MIBV-HI) titers of killed-MIBV-vaccinated birds decreased during the same period. The study indicates that killed MIBV vaccine offered no protection to birds exposed to AIBV. The same vaccine was quite effective against a homologous (MIBV) virus challenge.

Animals↗

PubMedDate not supplied

A dot-immunobinding assay for infectious bronchitis virus.

Common Whatman filter paper grade 1 and nitrocellulose membrane were compared for their sensitivity in a dot-immunobinding assay for detection of serum antibody titers to Arkansas avian infectious bronchitis virus (AIBV). For a blue to purple color detection, serum antibodies were bound to AIBV antigen adsorbed on the filter-paper discs or nitrocellulose membrane. Rabbit anti-chicken IgG horseradish-peroxidase (HRP) conjugate and hydrogen peroxide with 4-chloro-1-naphthol (HRP-color development reagent) were applied. The study indicates that very small amounts of antigen/antisera are needed for the dot-immunobinding assay. The test is sensitive, economical, and easy to run and can be completed within 6-8 hours.

Animals↗

PubMedDate not supplied

Effects of infectious bronchitis virus (Arkansas strain) on laying chickens.

Seventy-seven-week-old white leghorn layers were inoculated intraocularly with the Arkansas strain of infectious bronchitis virus (AIBV) to study the effects of the virus on egg production and on antibody response of the birds. Infected hens laid fewer eggs than the controls, and those eggs weighed less than eggs laid by controls. Further, the shell quality and internal quality of eggs laid by infected birds were inferior. The serum hemagglutination-inhibition (HI) titers of infected birds increased continuously through 4 weeks postinfection; serum HI titers of the controls were negligible.

Animals↗