Comparison of pyrimidine 5'nucleotidase activity in erythrocytes of sheep, dogs, cats, horses, calves, and Mongolian gerbils

Pyrimidine 5'nucleotidase (P5N) activities of erythrocytes for Mongolian gerbils, cats, dogs, sheep, horses, and calves were measured, using a radiometric technique with [14C]cytidine monophosphate as the substrate. Erythrocytes of gerbils had the highest activity [1,177.1 +/- 133.6 mU/g of hemoglobin (Hb)]. Feline erythrocytes had 327.4 +/- 204.4 mU/g of Hb. Canine erythrocytes had 148.0 +/- 19.8 mU/g of Hb. Ovine erythrocytes (44.3 +/- 20.9 mU/g of Hb), equine erythrocytes (30.0 +/- 15.9 mU/g of Hb), and bovine erythrocytes (14.1 +/- 6.9) had relatively low P5N activity. The P5N activity was approximately proportional to the reticulocyte percentage of and inversely proportional to the mean erythrocyte life span in these species.

A computer-interfaced photometer and systematic spacing of duplicates to control within-plate enzyme-immunoassay variation

A Multiskan photometer for reading microtiter plate enzyme immunoassays was linked with a time sharing computer to facilitate control of assay variation and analysis of results. The interface that converted photometer output to RS-232-C format required changes to divide the output into segments short enough for input to the computer. To measure within-plate variation and investigate how the method of allocating sample duplicates to plate wells may affect the estimation of sample variance, uniformity tests were conducted with 47 plates. Coefficients of variation (CV) among wells within-plates ranged from 4.6 to 20.7% and in two-thirds of the plates exceeded 10%. Duplicates allocated to adjacent wells (method 1) gave consistently higher CV for sample means than duplicates allocated to opposite plate quadrants (method 2). In general, the CV by method 2 was about 30% smaller than that by method 1. Analysis of variance confirmed the effectiveness of the quadrant pattern of duplicate allocation as a method of controlling variation that arises from well position effects.

Aplastic crisis due to parvovirus infection in pyruvate kinase deficiency

A thirteen-year-old boy with congenital haemolytic anaemia due to pyruvate kinase (PK) deficiency had an aplastic crisis. A serum parvovirus-like virus (SPLV) was demonstrated in the blood by electron microscopy and, subsequently, IgM and IgG antibodies to the prototype SPLV B19 were detected. In an attempt to define the level of erythropoiesis that is involved in parvovirus-induced bone marrow suppression, the levels of circulating early erythroid progenitors (burst forming units erythroid, BFU-E) were monitored during the crisis and recovery period. The virus-containing plasma inhibited the formation of BFU-Es from non-immune subjects and this effect was neutralised by convalescent serum. Colony forming units granulocyte-macrophage (CFU-GM) were also inhibited but this was probably non-specific since neutralisation did not reverse the effect. These experiments, together with the clinical data, suggest a selective effect of SPLV at the stage of erythroid progenitors.

Neutrophil movement in selected canine skin diseases

Neutrophilic movement was studied in dogs with atopy, 3 bacterial pyoderma syndromes, flea allergy dermatitis, and generalized demodicosis. Random neutrophil movement was decreased in generalized demodicosis, and this deficit correlated with the extent of body surface skin lesions. Neutrophilic chemotactic movement was decreased in 2 bacterial pyoderma syndromes: bacterial pyoderma, and staphyloccocal pyoderma. Although serum samples from diseased dogs showed no significant differences in chemoattractive qualities from normal pooled canine serum, control canine neutrophils incubated in demodectic dog serum showed decreased chemotactic responsiveness. It was postulated that demodectic dog serum had an inhibitor or deactivator of neutrophil chemotaxis.

Possible site of zinc control of hepatoma cell division in Wistar rats

The effect of zinc on the growth of a transplantable DAB hepatoma in young male Wistar rats was determined. Both a zinc deficiency (less than 0.5 microgram/g feed) as well as high levels of dietary zinc (500 micrograms/g feed) significantly reduced tumor growth. Both high- and low-zinc diets resulted in reduced activity of the salvage pathway of thymidine synthesis as well as reduced 32PO4 incorporation into DNA and diminished DNA polymerase activity. Blockage of the de novo pathway of DNA synthesis by the folate antagonist methotrexate (MTX) resulted in greatly increased flux through the thymidine salvage pathway and increased DNA polymerase activity but decreased 32PO4 incorporation in the transplantable hepatomas in Wistar rats fed normal zinc diets (50 micrograms/g feed). MTX had the effect of reducing all these activities in the groups fed low- and high-zinc diets. These data suggested a site of action of zinc associated with the salvage pathway of thymidine synthesis.

Marek's disease virus-induced transient paralysis: a comparison of lesions in susceptible and resistant lines of chickens

A study was conducted to determine the causative lesion of Marek's disease virus-induced transient paralysis. Brain histologic lesions were quantitated and compared in genetically resistant and susceptible inbred chickens. Comparisons were made 11 days post inoculation (PI) of virus when clinical signs were evident in susceptible birds and on day 17 PI when these signs had remitted. Clinically-affected birds from the susceptible line on day 11 PI had consistent evidence of neuropil vacuolation compatible with brain edema; two of these birds also had vasculitis. These lesions were absent in both clinically-recovered birds from this line evaluated on day 17 PI and genetically resistant birds studied on day 11 PI. Our findings suggest that the causative lesion of transient paralysis is vasogenic brain edema.

Demonstration that nonspecific bovine Brucella abortus agglutinin is EDTA-labile and not calcium-dependent

The binding site of B. abortus involved in nonspecific or false-positive agglutination by bovine serum was shown to be Ca++-independent in that binding of Ca++ by the chelating reagent DP2TA did not decrease titers. The reduction in agglutination by EDTA, EGTA, and DPTA was thought to be related to a common structural characteristic of these chelating reagents not exhibited by EDDA and DP2TA or to a lesser extent by DTPA. Removal of antigenic entities from the cell by the chelator was excluded as the cause of agglutination inhibition because agglutination by nonspecific IgM was not influenced by repeated washing of B. abortus by EDTA. The action of the chelators on the cell-agglutinin interaction was hypothesized to be a result of their competition with a receptor site on the cell for binding of the nonspecific or biochemically altered bovine IgM.

Demonstration that nonspecific bovine Brucella abortus agglutinin is EDTA-labile and not calcium-dependent

The binding site of B. abortus involved in nonspecific or false-positive agglutination by bovine serum was shown to be Ca++-independent in that binding of Ca++ by the chelating reagent DP2TA did not decrease titers. The reduction in agglutination by EDTA, EGTA, and DPTA was thought to be related to a common structural characteristic of these chelating reagents not exhibited by EDDA and DP2TA or to a lesser extent by DTPA. Removal of antigenic entities from the cell by the chelator was excluded as the cause of agglutination inhibition because agglutination by nonspecific IgM was not influenced by repeated washing of B. abortus by EDTA. The action of the chelators on the cell-agglutinin interaction was hypothesized to be a result of their competition with a receptor site on the cell for binding of the nonspecific or biochemically altered bovine IgM.

Pyrimidine-specific 5' nucleotidase activity in bovine erythrocytes: effect of phlebotomy and lead poisoning

Erythrocyte pyrimidine-specific 5' nucleotidase (PY5'N) (E.C. 3.1.3.5) was measured in healthy, anemic, and lead-poisoned calves to determine whether low activity of PY5'N is associated with the propensity of cattle to develop basophilic stippling of erythrocytes. Low activity of PY5'N has been associated with basophilic stippling of erythrocytes in persons with inherited hemolytic anemia and with lead poisoning. A radiometric technique, using [14C]cytidine monophosphate as the substrate, was used to measured PY5'N activity. The erythrocytes from 4 healthy calves had much lower activity (mean of 7.1 +/- 1.6 nmols of [14C]cytidine monophosphate hydrolyzed/min/g of hemoglobin) than has been reported for human erythrocytes. The pH response curve of bovine PY5'N was similar to that of the human enzyme, with maximal activity around pH 7. Experimental hemorrhagic anemia in these calves increased PY5'N activity 6-to 7-fold, with peak activity occurring concomitantly with maximum reticulocytosis. Two of the calves were then given lead per os, and the PY5'N activity decreased within 24 hours to base-line values. In the 2 other calves not given lead, the PY5'N activity declined slowly, but did not reach base-line values after 14 days.

Erythrocyte protoporphyrin in experimental chronic lead poisoning in calves

Erythrocyte protoporphyrin was measured in calves by the free erythrocyte porphyrin (FEP) test. The FEP of 15 healthy calves was 142.8 +/- 32.4 micrograms/dl (mean +/- SD) of packed erythrocytes or 45.6 +/- 10.3 micrograms/dl of whole blood. Biweekly oral lead administration to 3 calves produced a continuous increase of FEP to between 2,800 and 6,033 micrograms/dl of packed erythrocytes after 20 weeks. Fluorescence scans of diluted blood were used to demonstrate that erythrocyte protoporphyrin from lead-poisoned calves was present as an approximately 2:1 mixture of zinc protoporphyrin and free protoporphyrin. Blood lead concentration increased in calves after lead was given (orally), but had greater weekly fluctuations than FEP. Mild anemia developed in 2 of 3 animals late in the experiment. Basophilic stippling of erythrocytes occurred in 1 calf.

Evaluation of antibovine IgG subclass specific antisera from guinea pigs and goats

A technique for producing specific antibovine IgG2 antibodies is described. The method relies on the abrogation of the class-specific antibody response of guinea pigs to bovine IgG1 by intravenous injection of goat serum immediately before immunisation in the foot pads with bovine IgG2 in adjuvant. Of the 10 resulting antisera, six were judged monospecific for IgG2 by immunoelectrophoresis but, of these, two antisera gave a very faint line in gel diffusion using IgG1 as the antigen. Radial immunodiffusion studies indicated that the strength of the antisera, using IgG2 as the antigen, was similar to antisera of guinea pigs not injected with goat serum before absorption with bovine IgG1. For guinea pigs injected with goat serum, using bovine IgG1 as an immunogen did not result in the production of subclass specific antisera, rather, the specificities were similar to those of animals not receiving goat serum. This data is compared to absorption studies of goat antibovine IgG1 and IgG2 antisera. The relationships of goat and bovine IgG subclasses are discussed.

Bovine paratuberculosis III. An evaluation of a whole blood lymphocyte transformation test

A whole blood lymphocyte transformation test was used to examine cattle with varying degrees of infection with Mycobacterium paratuberculosis. Minimally infected animals characteristically responded to johnin purified protein derivative in the lymphocyte transformation test but did not routinely react on serological and/or skin testing. Heavily infected animals showed considerable variation in their lymphocyte transformation responses to antigen and some of them were consistently unresponsive. Antigen induced lymphocyte transformation reactions were recorded in 7.6 to 41.5% of uninfected animals whose infection status was determined by bacteriology and/or histopathology. The number of positive reactions recorded in uninfected animals depended on the population, the larger percentage being found in a herd with a proven history of paratuberculosis. The potential of lymphocyte transformation as a diagnostic test for bovine paratuberculosis is discussed.

Two equine true hermaphrodites with 64,XX/64,XY and 63,XO/64,XY chimerism

The karyotypes of a Welsh pony and a Standardbred were 64,XX/64,XY and 63,XO/64,XY respectively. Both intersexes were true hermaphrodites with bilateral ovotestes. Neither intersex showed stallion-like behaviour. Each one had an underdeveloped penis, bilateral seminal vesicles and uterine tissue. It would appear that the chimerism in these equine intersexes resulted from double fertilization or fusion of blastocysts. Mosaicism in the Standardbred is a possibility, resulting from loss of a Y chromosome by anaphase lag in an early embryonic XY cell.

Effect of Sample Preparation on Basophilic Stippling in Bovine Blood Smears

The effect of sample preparation on the amount of basophilic stippling of erythrocytes (BSE) was studied using blood from a calf with chronic experimental lead poisoning. The combination of EDTA anticoagulation and rapid drying of the blood smear resulted in the most BSE. Alcohol prefixation reduced BSE. Wright-Leishman stain was better than Wright stain in demonstrating BSE.

Bovine paratuberculosis II. A comparison of fecal culture and the antibody response

Fecal culture for Mycobacterium paratuberculosis and a complement fixing serological test using a carbohydrate antigen were compared for diagnostic efficiency in cattle naturally infected with M. paratuberculosis. Serological reactivity was associated with the persistent fecal shedding of large numbers of bacteria and in the absence of false positives in the population studied, was considered an efficient method for the identification of this segment of infected cattle. Minimally infected cattle, which inconsistently shed small numbers of bacteria, were generally serologically negative. One persistent fecal shedder demonstrated a fluctuating serological response to the carbohydrate antigen following abortion. The advantages and disadvantages of this serological diagnostic procedure in relationship to fecal culture are discussed.

Bovine paratuberculosis I. A herd study using complement fixation and intradermal tests

A dairy herd (102 cattle) which had been enrolled under a paratuberculosis control program for two years utilizing a complement fixation test (carbohydrate antigen) and intradermal skin test (johnin PPD) was subjected to two further herd tests and followed to slaughter to determine infection status by culture and histology. Mycobacterium paratuberculosis infection was demonstrated in 37 of the animals of which only five were considered reactors on the basis of the last two herd tests applied. Cultural and histopathological evaluation indicated the testing procedures had eliminated heavily infected animals. The limitations of these testing procedures under free stall housing conditions are discussed.

Cytology of canine cutaneous round cell tumors. Mast cell tumor, histiocytoma, lymphosarcoma and transmissible venereal tumor

Sixty-four canine cutaneous round cell tumors were divided into 25 mast cell tumors, 15 histiocytomas, nine cutaneous lymphosarcomas and 15 transmissible venereal tumors. The final diagnosis was made from cytologic, clinical and histologic findings. Cytologic features were significantly distinctive in mast cell tumor, transmissible venereal tumor, and most cases of histiocytoma and lymphosarcoma to allow a diagnostic opinion. This opinion was supported by subsequent histologic examination. In some instances cytology was considered essential in rendering a diagnostic opinion even though histology was available.

Bovine fetal inoculations with calf rotavirus

The serological and histopathological responses of bovine fetuses to in utero inoculation with virulent and attenuated strains of the calf rotavirus (reovirus-like agent of neonatal calf diarrhea) are described. Thirteen bovine fetuses, 63 to 190 days of gestation, were inoculated in utero with attenuated (three fetuses) or field strain virus (nine fetuses) or both (one fetus).Serum-neutralizing antibody titers ranging from 1:16 to > 1:256 were detected in six of eight fetuses tested, demonstrating the ability of the bovine fetus to respond immunologically to this agent. The youngest fetus in the series was inoculated at 63 days of gestation and developed a titer of 128 in 64 days. This represents the earliest stage of gestation at which a bovine fetus has been inoculated with a bovine virus and found to produce antibody to it. Serum neutralizing titers in six of the eight dams tested increased significantly following the inoculations of their fetuses in utero. Histological changes associated with viral replication and antigenic stimulation of the lymphoreticular system were observed. Pneumonic lesions consisting of both local and diffuse lymphoreticular proliferation were present in five of the nine fetuses that were alive at slaughter. Gliosis and perivascular cuffing were noted in the brains of two of these fetuses and meningitis was seen in one. No evidence of teratogenic change was found.

Serological response of the bovine fetus to bovine viral diarrhea virus

Susceptible pregnant heifers were inoculated with bovine viral diarrhea virus at 150 days of gestation and earlier. Fetuses were surgically collected at selected times after inoculation. Serum immunoglobulins were quantitated, and the presence of specific antibodies was determined. In fetuses from heifers inoculated at 150 days, immunoglobulin M (IgM) appeared approximately 2 weeks after inoculation and was followed in 7 days by IgG1. Later IgG2 was detected in the sera of three fetuses. Serum-neutralizing and complement-fixing antibodies were first detected in a fetus taken at 206 days of gestation. Fetuses taken at later times also had specific serum antibodies. Possible explanations for the appearance of serum immunoglobulin substantially before specific bovine viral diarrhea antibodies include the viral alteration of host tissues rendering them antigenic viral activation of polyclonal B cells, and viral modulation of virus-specific lymphocytes causing specific interference with the appearance of antiviral antibodies. In one of the fetuses having IgG2, the serum also contained IgA. Placental leakage of material immunoglobulins was thought to be responsible for the presence of IgA and IgG2 in this fetus. Small quantities of IgM were found in the serum of two fetuses taken from heifers inoculated between 65 and 95 days of gestation, but specific antibodies were found in none.

The Hematology of Lead Poisoning in Man and Animals

The hematologic abnormalities are used to aid in diagnosis and understanding of the pathophysiologic mechanisms of lead poisoning. Erythrocyte shape abnormalities, basophilic stippling, porphyrin abnormalities and normoblastosis have been associated with lead ingestion in many species. This paper reviews literature on these aspects of hematology of lead poisoning in both man and domestic animals.

Determination of the Concentration of Protein in Cerebrospinal Fluid With A New Dye-Binding Method

The protein concentration of cerebrospinal fluid (CSF) was measured on 50 samples with a new dye-binding method using Coomassie Brilliant Blue G-250 (CBB). The results of this method correlated well (r = 0.99) with those of the trichloroacetic acid-Ponceau S method (TCA-PS). Since the CBC method involves only one step, it is recommended as a simple method of determining protein concentration in CSF.

Intestinal absorption of zinc: a role for a zinc-binding ligand in milk

This study examined the proposal that a low molecular weight, zinc-binding ligand (ZBL) in certain milks is important for zinc absorption in the neonatal period. Ten-day-old rats, in which intestinal ZBL is absent, fed (by stomach intubation) 65Zn-labeled ZBL from rat milk, absorbed significantly more 65Zn than those fed free 65ZnCl2 or bovine milk fractions. ZBL from human milk appeared to have an intermediate effect, possibly due to species specificity. 65Zn was found in the ZBL fraction in intestinal mucosa of 10-day-old rats fed rat or human milk fractions, but not in those fed bovine milk or free 65ZnCl2. In contrast, in 18-day-old rats, which have an endogenous intestinal ZBL, there were no differences in zinc absorption, and any of the labeled milk fractions or free 65Zn caused localization of 65Zn in the ZBL fraction of intestinal mucosa. These results support the hypothesis that the intestinal ZBL plays a role in zinc absorption and that in the neonatal period before its development the milk ZBL is valuable for this function. This mechanism may be important in normal human infants as well as in acrodermatitis enteropathica patients.