Neonatal neutropenia in an Arabian foal.
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Biomedical subjects
Publications and source records attributed to E G Davis.
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This paper describes a method for simultaneously measuring phagocytosis and oxidative burst activity in equine peripheral blood leukocytes by flow cytometry. Opsonized propidium iodide-labelled Staphylococcus aureus (PI-Sa) was used to measure the uptake of bacteria by equine phacocytes and the oxidative burst activity by oxidation of dihydrorhodamine 123. The requirements to achieve optimal activity of phagocytosis and oxidative burst are described. The advantage of the simultaneous technique is that it provides both independent and comparative values for phagocytosis and the oxidative burst, for the detection of impaired mechanisms of microbial destruction. Furthermore, the technique allows evaluation of opsonization activity in this context.
OBJECTIVE: To evaluate clinical response, pulmonary function, and adrenal gland response to incremental doses of beclomethasone dipropionate in horses with recurrent airway obstruction. DESIGN: Crossover trial. ANIMALS: 8 horses with recurrent airway obstruction. PROCEDURE: Horses randomly assigned to 4 groups were treated twice daily via aerosol administration of placebo or 500, 1,000, or 1,500 micrograms of beclomethasone dipropionate in a crossover design with a 10-day minimum washout period. Subjective assessment of airway obstruction, serum cortisol concentration, and maximum change in pleural pressure during tidal breathing (delta Pplmax) were determined daily prior to morning drug administration, and delta Pplmax was reevaluated 15 minutes after morning drug administration. Pulmonary resistance and dynamic compliance were determined at baseline and approximately 12 hours after the final treatment. RESULTS: An immediate treatment effect was not identified. Within 24 hours, delta Pplmax and airway obstruction were lower in horses receiving beclomethasone. Onset and magnitude of response was similar among the 3 beclomethasone dose regimens. Pulmonary resistance was improved only after administration of all 3 doses of beclomethasone, whereas dynamic compliance was improved after administration of 1,000 micrograms and 1,500 micrograms of beclomethasone. Reduction in serum cortisol concentration occurred with all 3 beclomethasone dose regimens; however, the magnitude of adrenal gland suppression was greater in horses receiving 1,000 or 1,500 micrograms of beclomethasone. CONCLUSIONS AND CLINICAL RELEVANCE: Low-dose (500 micrograms) beclomethasone administration caused similar, improvement in pulmonary function, compared with high-dose beclomethasone (1,000 and 1,500 micrograms), with the exception of dynamic compliance, and caused less suppression of endogenous cortisol production.
Studies in infants and foals indicate an age-dependent maturation of peripheral lymphocyte subsets. The age-dependent relationship for maturation of cellular immune responses, such as phagocytosis and lymphocyte responses of the peripheral and pulmonary-derived leukocytes, has not been characterized in foals. Lymphocyte subpopulations, mitogen stimulation response of lymphocytes, lymphokine-activated killing cell activity, phagocytosis and oxidative burst activity, and serum immunoglobulin (Ig) classes G and M concentrations were determined in developing foals. This study illustrates age-dependent changes in immunoglobulin class concentrations, lymphocyte subsets, and EqMHC Class II expression in cells of the peripheral blood and lungs of developing neonatal-to-weanling foals. The increase in peripheral blood and BAL B-lymphocytes and serum immunoglobulins in developing foals suggests expansion of immune cell populations during a time in which environmental pathogen exposure is great. General immune function, mitogenic responses, LAK cell activity, opsonized phagocytosis, and oxidative burst activity of newborns was similar to the adult horse. Total immune-cell numbers, rather than function, seemed to be the limiting factor in the development of the equine neonatal immune system. There was an age-related percent increase in the appearance of pulmonary lymphocytes, but a percent decrease in macrophages. Although development of the respiratory immune system follows changes in the peripheral blood, cellular expansion, activation, and migration may occur at a slower pace, making the respiratory environment susceptible to pathogens prior to optimal immune system maturity.
BACKGROUND: This study hypothesizes that predicted polymorphism of the interferon-gamma receptor 1 gene may play an important role in infection after trauma as supported by microsatellite analysis. METHODS: DNA was extracted from the peripheral leukocytes of 38 trauma patients with Injury Severity Scores greater than 16. D6S471, a microsatellite marker on chromosome 6 near interferon-gamma receptor 1, was amplified with polymerase chain reaction, and genotypes were determined. RESULTS: The mean Injury Severity Score was 32, and 63% of patients (24 of 38) developed major infection. Three alleles and 5 genotypes were identified for D6S471. Twenty-six percent of patients (10 of 38) had genotype AA, all of whom developed major infection (P =.004). Genotype BB accounted for 57% of the uninfected population (8 of 14) but only 21% of the infected group (P =.028). Allele A had a frequency of 33%, of which 22 alleles (88%) were found in infected patients (P =.001). In addition, allele B accounted for 61% of the uninfected group (17 of 28) but only 23% (11 of 48) of the infected group (P =.001). Allele C demonstrated no correlation. CONCLUSIONS: Microsatellite polymorphism correlates strongly with infection. These findings portend polymorphism in the receptor itself and thereby represent a genetic basis for the development of infection. We suggest this identifies a high-risk group who could benefit from more specific therapy that may have the potential to overcome this receptor insufficiency.
A 5-y-old Paint horse gelding was evaluated for acute laminitis after exposure to black walnut shavings. The gelding's feet were previously soaked in an ice bath continuously for approximately 24 h. Treatment consisted of anti-inflammatory and vasodilator therapy. Serial radiographs revealed progressive palmar deviation of the third phalanx and subsolar abscesses in both forefeet. The gelding developed purulent discharge from the right coronary band and the hoof wall detached circumfrentially. Euthanasia was elected after 54 days. Continual exposure of the gelding's feet to ice water temperatures may have caused decreased perfusion and increased edema formation in the laminae resulting in decreased blood flow and exacerbating the existing ischemic necrosis.
BACKGROUND: There is mounting confusion as to which anatomic scoring systems can be used to adequately control for trauma case mix when predicting patient survival. METHODS: Several Abbreviated Injury Scale (AIS) and International Classification of Disease Clinical (ICD-9CM)-based methods of scoring severity were compared by using data from the Pennsylvania Trauma Outcome Study. By using a design dataset, the probability of survival was modeled as a function of each score or profile. Resulting coefficients were used to derive expected probabilities in a test dataset; expected and observed probabilities were then compared by using standard measures of discrimination and calibration. RESULTS: The modified Anatomic Profile, Anatomic Profile, and New Injury Severity Score outperformed the International Classification of Disease-based Injury Severity Score. This finding remains true when AIS values are obtained by means of a conversion from International Classification of Disease to AIS. CONCLUSION: Results support the integrity of the AIS and argue for its continued use in research and evaluation. The modified Anatomic Profile, Anatomic Profile, and New Injury Severity Score, however, should be used in preference to the Injury Severity Score as an overall measure of severity.
OBJECTIVE: To determine whether pulmonary distribution of aerosolized technetium Tc 99m pentetate is improved after inhalation of a single dose of albuterol sulfate in horses susceptible to recurrent airway obstruction (heaves). ANIMALS: 6 horses with heaves and 4 horses with normal respiratory tract function. PROCEDURE: Images were obtained during ventilation of horses at baseline (maximal change in pleural pressure during tidal breathing [deltaPpImax] >15 cm H2O) and after aerosolized albuterol sulfate (360 microg) administration, with a 24-hour washout period between experiments. The deltaPpImax was determined prior to the baseline scan, prior to albuterol sulfate administration, and 5 minutes after albuterol sulfate administration. Images were assessed by visual inspection (semi-quantitative scoring system) and histogram analysis. RESULTS: Images obtained from horses with heaves had nonuniform pulmonary distribution of radionuclide characterized by poor penetration in peripheral lung fields and excess deposition in large airways. Histogram analysis of images of the caudal portions of the lungs revealed nonuniform radionuclide deposition in horses with heaves and uniform radionuclide deposition in control horses. CONCLUSION: Administration of a single dose of aerosolized albuterol sulfate improved pulmonary distribution of aerosolized radiolabeled pentetate suspension in horses with heaves but did not alter pulmonary distribution in clinically normal horses. CLINICAL RELEVANCE: Precedent bronchodilator administration may improve pulmonary distribution of aerosolized, surface-active anti-inflammatory preparations.
OBJECTIVE: To estimate sensitivity and accuracy of subjective evaluation of mild lameness in horses during treadmill locomotion and to correlate subjective evaluation with kinematic analysis. ANIMALS: 19 lame and 5 clinically normal horses. PROCEDURE: Lameness was evaluated by subjective score and kinematic analysis before and after palmar digital nerve block (PDNB). Evaluations were made by 6 clinicians and 7 interns or residents. Within- and between-observer agreement analyses (kappa values) were calculated and compared, using a Student's t-test. Pearson's product-moment correlation coefficients were calculated between clinician's change in score and the change in kinematic variables after PDNB. RESULTS: Within-observer agreement was within the range expected for conditions of moderate diagnostic difficulty. Within-observer agreement was higher for clinicians than for interns or residents. Between-observer agreement was acceptable for scores within 1 value of each other. Between-observer agreement of change in lameness score after PDNB was poor. When kinematic variables were ranked with each clinician's subjective change in score, only 2 were among the top 3 for the majority of clinicians. Asymmetry of vertical head movement between contralateral forelimb stance phases and the point of maximum hoof height during swing decreased as lameness subjectively improved. CONCLUSION: Mild lameness may be difficult to evaluate during treadmill locomotion. Although clinicians were more repeatable in their subjective evaluation of lameness than interns or residents, they were not more reliable at detecting the true state of lameness. CLINICAL RELEVANCE: Lack of agreement between clinician scoring of mild lameness emphasizes the need to use more objective measures for quantifying lameness.
Disseminated geotrichosis was diagnosed at necropsy of 2 unrelated dogs from the same household. Clinical signs of disease included fever, coughing, anorexia, listlessness, polydipsia, and dyspnea. The duration of clinical illness was less than 2 weeks. Pathologic findings in both dogs were similar and consisted of pyogranulomatous pneumonia, hepatitis, and nephritis. Geotrichum candidum was identified by fluorescent antibody technique.
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A gas chromatographic procedure was developed to measure SO2 in the presence of water vapour up to saturation level in the headspace atmospheres of packaged food. A Teflon column packed with Chromosorb 108 was used to separate CO2, SO2, and H2O in that order, then SO2 was determined using an electrolytic conductivity detector operated in a non-catalytic mode. A permeation-tube apparatus, producing SO2 and modified to permit humidification of the effluent stream, was used to calibrate the instrument, and a heated syringe technique was devised which overcame problems of sampling low levels of SO2 in the presence of water vapour. In food headspaces the method was used to determine SO2 at the ng ml-1 level with relative deviations of less than 5%.
Venous blood T cell phenotypes were analysed with monoclonal antibodies after 11 allogeneic and 17 autologous bone marrow transplants. In seven cases studied in the early regenerative period, cells with a thymocyte phenotype were present in the blood. In the large majority of patients treated with both allografts and autografts there was an imbalance of phenotypic 'helper' and 'suppressor' T cell subsets with initially a relative and later an absolute increase of 'suppressor' T cells. This imbalance was still present at over 250 d in eight out nine cases. Suppressor T cells bearing HLA-Dr antigens were abundant in one case of fatal GVHD but not in another, and were also increased following two autografts. It is concluded that T cell phenotyping is not of diagnostic value in sick patients following bone marrow transplantation when graft-versus-host disease is suspected.
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Organophosphorus compounds have been shown to exhibit toxic behavior as insecticides, pesticides, and mammalicides. Soman and 21 related compounds were studied for possible structure-activity relationships. Computer-aided methods were used to generate a linear expression relating the activity (ln [1/LD50], rabbit I.V.) of the compounds to three structure-based descriptors (R = 0.96). Principal components regression and jackknife analysis were performed to assess the stability of the model.