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. After blocking, membranes were incubated with ET-A or ET-B antisera (dilution, 1:500) for 1 hour at 25°C. Membranes were then washed with TBSS containing 0.1% Tween and incubated with donkey anti-sheep IgG−horseradish peroxidase conjugate. m After

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in American Journal of Veterinary Research

Abstract

Objective

To determine whether Mycobacterium paratuberculosis could survive in colostrum after pasteurization. Additionally, this study investigated the effect pasteurization had on IgG concentration in colostrum.

Animals

Colostrum samples were collected from cattle (beef and dairy) owned by the state of Ohio.

Procedure

Colostrum was divided into aliquots and inoculated with variable concentrations of M paratuberculosis (ATCC No. 19698: 104, 103, and 102 colony-forming units/ml). Half the samples at each concentration were subjected to pasteurization temperatures (63 C) for 30 minutes and the remainder were kept at approximately 20 to 23 C. All samples were incubated (Herrold's egg yolk medium with and without mycobactin J) and observed for growth during the next 16 weeks. Additionally, the IgG concentration of colostrum was determined by radioimmunoassay before and after pasteurization. Samples that coagulated at pasteurization temperatures were mechanically resuspended before measurement of IgG concentration.

Results

Growth of M paratuberculosis was retarded but not eliminated by pasteurization. Growth was observed in all unpasteurized samples incubated on Herrold's egg yolk medium with mycobactin J but in only 2 of 18 pasteurized samples similarly cultured. Growth from pasteurized samples appeared 5 to 9 weeks after growth was observed from nonpasteurized samples.

Mean colostral IgG concentration was 44.4 g/L in nonpasteurized samples and 37.2 g/L in pasteurized sample, a decrease of 12.3%. High-quality colostrum (> 48 g of IgG/L) had a significantly greater loss of IgG concentration than did colostrum of lesser quality (P = 0.002).

Conclusions

Pasteurization lessened, but did not eliminate, growth of M paratuberculosis from experimentally inoculated colostrum samples. Pasteurization resulted in a significant decrease in colostral IgG concentration but not to an unmanageable level that would preclude the colostrum's use for passive transfer of immunity.

Clinical Relevance

Colostrum is macrophage rich and may serve as a source of M paratuberculosis infection to calves. Pasteurization of colostrum may lessen the risk of infection, but will not totally eliminate M paratuberculosis. (Am J Vet Res 1996;57:1580–1585)

Free access
in American Journal of Veterinary Research

Objective

To determine effects of blood contamination on western blot (WB) analysis of CSF samples for detection of anti-Sarcocystis neurona antibodies, and on CSF albumin and IgG concentrations, albumin quotient (AQ), and IgG index in horses.

Design

Prospective in vitro study.

Samples

Blood with various degrees of immunoreactivity against S neurona was collected from 12 healthy horses. Cerebrospinal fluid without immunoreactivity against S neurona was harvested from 4 recently euthanatized horses.

Procedure

Blood was serially diluted with pooled nonimmunoreactive CSF so that final dilutions corresponded to 10-3 to 100 μl of blood/ml CSF, and WB analysis was performed on contaminated CSF samples. Number of RBC, albumin and IgG concentrations, AQ, and IgG index were also determined.

Results

Antibodies against S neurona were detected in CSF contaminated with 10-3 μl of strongly immunoreactive blood/ml. In CSF samples contaminated with 10 μl of blood/ml, AQ remained within reference range. Volume of blood required to increase IgG index varied among blood samples and was primarily influenced by serum IgG concentrations. Number of RBC in contaminated samples was correlated with volume of blood added, but not with degree of immunoreactivity detected in contaminated CSF samples.

Conclusions and Clinical Relevance

During collection of CSF from horses, contamination with blood may introduce serum antibodies against S neurona at concentrations sufficient for detection by WB analysis, thus yielding false-positive results. When blood is moderately or strongly immunoreactive, the amount of contaminating albumin may be small enough as to not increase AQ above reference range. In these cases, AQ and IgG index should be interpreted with caution. (J Am Vet Med Assoc 1999;215:67—71)

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in Journal of the American Veterinary Medical Association

Objective

To determine the relationship between serum ɣ-glutamyltransferase (GGT) activity and serum IgG concentration in neonatal crias.

Design

Prospective observational study.

Animals

21 llama and 4 alpaca crias from 0 to 5 days old.

Procedure

Serum GGT activity was measured, using a commercially available kit. Serum IgG concentration was determined by use of radial immunodiffusion. With a serum IgG concentration of 1,000 mg/dl (considered adequate passive transfer), specificity and sensitivity of serum GGT activity in the detection of failure of passive transfer were determined. Regression models were developed to determine the relationship between serum GGT activity and serum IgG concentration.

Results

Sensitivity ranged from 0.56 to 0.89, and specificity ranged from 0.88 to 0.31, depending on the value of serum GGT activity chosen as a threshold. Proportion of crias correctly classified ranged from 0.76 to 0.52. Regression models failed to demonstrate a significant relationship between serum GGT activity and serum IgG concentration.

Clinical Implications

Passive transfer status in crias cannot be accurately predicted on the basis of serum GGT activity. (J Am Vet Med Assoc 1997;211:1165–1166)

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in Journal of the American Veterinary Medical Association

Summary

Serologic evidence of infection by Toxoplasma gondii, feline leukemia virus, feline coronaviruses, or feline immunodeficiency virus (fiv) is commonly found in cats with uveitis. Serum samples from 124 cats with uveitis were assayed by use of elisa for the detection of T gondii-specific immunoglobulin M (IgM), IgG, and circulating antigens (Ag), as well as an elisa for feline leukemia virus Ag, an elisa for antibodies to fiv, and an indirect fluorescent antibody assay for antibodies to feline coronaviruses. Serologic evidence of infection by 1 or more of the infectious agents was detected in 83.1% of the samples. Serologic evidence of T gondii infection, defined as the detection of T gondii-specific IgM, IgG, or Ag in serum, was found in 74.2% of the samples. The seroprevalence of T gondii infection was significantly greater in cats with uveitis than in healthy cats from a similar geographic area. Serum samples from cats with serologic evidence of both T gondii and fiv infections were more likely to contain T gondii-specific IgM without IgG than samples from cats with serologic evidence of T gondii infection alone. Cats with serologic evidence of fiv and T gondii coinfection had a higher T gondii-specific IgM titer geometric mean and a lower T gondii-specific IgG titer geometric mean than did cats with serologic evidence of T gondii infection alone. Serologic evaluation for T gondii infection should include assays that detect IgM, IgG, and Ag, particularly in cats coinfected with fiv.

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in Journal of the American Veterinary Medical Association

Summary

Paired csf and serum samples were obtained from 109 rhesus macaques aged 1 to 18 years. The csf and serum IgG and albumin concentrations were determined, using radial immunodiffusion; csf total protein and glucose were determined, using colorimetric methods; and Na, K, and Cl concentrations were determined, using ion-specific electrodes. The csf protein values were lower than those reported for non-human primates, and this finding was confirmed by results of agar gel electrophoresis. Animal age and sex had no significant effects on csf composition, but serum IgG concentration increased with age. Concentrations of total protein, albumin, and IgG were greater, and concentrations of glucose and potassium were lower in csf obtained from the lumbar rather than the cisternal site. Composition of csf was not significantly altered by contamination with blood at values up to 10,000 RBC/μl. The csf albumin quotient, IgG quotient, and IgG index were determined and differed markedly from values reported for human beings, indicating that the properties and specificity of the blood-brain barrier may be species-specific.

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in American Journal of Veterinary Research

features including skin ulcers and/or intestinal granulomas in the infected species, positive ELISA serologic reactivity detecting high anti– P insidiosum IgG titers, the presence of 2 to 3 identity bands on an immunodiffusion assay, and positive results

Full access
in Journal of the American Veterinary Medical Association

Summary

Six foals were deprived of colostrum for the first 36 hours after birth and, instead, received reconstituted powdered milk. Five control foals suckled their dams naturally. Blood samples were obtained from all the foals after birth and at approximately weekly intervals until at least 5.5 months of age. Sera were analyzed for hemolytic complement activity, complement component C3, and correlating IgG concentration. Hemolytic complement (P = 0.0145) and C3 (P = 0.0002) values were significantly higher in colostrum-deprived foals (cdf) than in naturally nursed foals at 2 to 5 days of age. In addition, significantly (P = 0.0149) higher IgG concentration was found in cdf than in naturally nursed foals between 3 and 5.5 months of age. It was concluded that the observed high complement activity in cdf within 2 to 5 days of age may provide an alternative in immune defense for IgG-deprived foals after failure of colostral transfer.

Free access
in American Journal of Veterinary Research

Summary

Immunoelectrophoresis and single radial immunodiffusion were used to identify and measure tear immunoglobulin concentrations in 50 healthy dogs. Immunoglobulin A and IgG were detected in all samples analyzed, whereas IgM was not detected in any sample. Mean IgA concentration was 25.28 ± 1.9 mg/dl, adult dogs (> 18 months) having significantly higher mean value. The IgA concentration related to age had significant (P < 0.006) positive correlation; mean IgG concentration was 23.10 ± 1.72 mg/dl. Linear correlation analysis revealed significant (P < 0.0007) correlation coefficient between tear total protein and IgA concentrations. The IgA and IgG concentrations also were significantly (P < 0.0001) correlated when expressed as milligrams per 100 mg of protein. Relation with sex was not established for either immunoglobulin.

Free access
in American Journal of Veterinary Research

SUMMARY

Immunoturbidimetric determination of serum IgG concentration in foals was compared with the reference methods of single radial immunodiffusion and serum protein electrophoresis. High positive correlations were discovered when the technique was compared with either of these reference methods. The zinc sulfate turbidity test for serum IgG estimation was also evaluated. Although a positive correlation was discovered when the latter method was compared with reference methods, it was not as strong as the correlation between reference methods and the immunoturbidimetric method.

The immunoturbidimetric method used in this study is specific and precise for equine serum IgG determination. It is rapid and, thus, is advantageous when timely evaluation of critically ill foals is necessary. The technique should be adaptable to various spectrophotometers and microcomputers for widespread application in veterinary medicine.

Free access
in American Journal of Veterinary Research