bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of an attenuated strain of Actinobacillus pleuropneumoniae, serotype 1
Authors: Rosendal S. , MacInnes J. I.
Published: January 2024

Pleuropneumonia is an important disease of swine caused by Actinobacillus pleuropneumoniae. Putative virulence determinants include capsule, lipopolysaccharide, and cytotoxin. We studied the virulence and virulence determinants of 2 strains: CM5 and CM5A of serotype 1. Strain CM5 was isolated from a pig with pleuropneumonia and passaged once in vitro; strain CM5A was a substrain of CM5 passaged 70 times in vitro. Pigs challenge exposed to an aerosol of 1.3 × 107 colony-forming units of CM5/ml died within 30 hours; pigs challenge exposed to an aerosol of 1.6 × 108 colony-forming units of CM5A/ml survived. The average thickness of the capsular layer was 137 nm in strain CM5 and 53 nm in strain CM5A in bacteria treated with homologous antibody and examined by transmission electron microscopy. Similarly, capsular material binding polycationic ferritin was found in colonies of strain CM5, but not in strain CM5A. The ratio of hexosamine to protein in extracted capsule of CM5 was more than twice that of CM5A.

The polyacrylamide gel electrophoretic profile of the lipopolysaccharide, outer membrane proteins, and whole cell proteins did not differ between the 2 strains. Also, the amount of cytotoxin or endotoxin produced by the 2 strains during the logarithmic growth phase was not different. The electrophoretic profile of restriction endonuclease digested dna was similar, with the exception of bands in the 750- and 620-basepair regions. It was concluded that attenuation of strain CM5A during in vitro passage was a result of reduced capsule production and that encapsulation is an important virulence determinant of A pleuwropneumoniae, serotype 1.
Endogenous prostanoids control ion transport across neonatal porcine ileum in vitro
Authors: Argenzio Robert A. , Liacos James A.
Published: January 2024

In contrast to the net absorption of Na and Cl ions observed in vivo, porcine small intestine had a net secretion of these ions in vitro. These discrepancies between in vivo and in vitro results have led to difficulties in interpretation of studies investigating mechanisms of intestinal secretion and diarrhea in this species. To examine the influence of endogenous prostanoids on ion transport in neonatal porcine ileum in vitro, tissues were prepared and studied in indomethacin. Net absorption of Na, reversal of net Cl secretion to net absorption, and decreased short circuit current were observed. Conversely, addition of prostaglandins to indomethacin-treated tissues reversed these effects and reestablished conditions similar to those observed in control tissues. Control tissue was essentially refractory to the effects of exogenous prostaglandins. Results indicate that under in vitro conditions, ion transport in neonatal porcine ileum is tightly regulated by endogenous prostanoids that abolish the neutral NaCl absorptive mechanism and elicit electrogenic Cl secretion. However, concentrations of these prostanoids may have been artificially high as a result of tissue preparation for in vitro study.
Hypermetabolic priming of canine neutrophils by 7-S nerve growth factor
Authors: Gruber Dale F. , O'Halloran Kevin P. , D'Alesandro Michele M. , Farese Ann M.
Published: January 2024

Canine circulating neutrophils, isolated by a blood lysing technique, were incubated with 7-S nerve growth factor (ngf), at final concentrations between 12.5 and 800 ng/ml, for 30 minutes at 37 C. Neutrophil cytosolic H2O2 production, measured by flow cytometry, after 7-S ngf incubation was not significantly different from that produced at 37 C (baseline temperature controls) alone. Phorbol myristate acetate (pma; 100 ng/ml) stimulation of neutrophils produced cytosolic H2O2 concentrations almost 13 times that of baseline temperature control neutrophils. Preincubation of neutrophils with 7-S ngf (100 to 800 ng/ml, 30 minutes, 37 C) and subsequent stimulation by pma resulted in augmented H2O2 production in excess of twice that of neutrophils treated with pma alone, and almost 30 times that of baseline temperature controls.
Fibrin/fibrinogen in lungs and respiratory secretions of horses with chronic pulmonary disease
Authors: Winder N. Christine , Grünig Gabriele , Hermann M. , von Fellenberg R.
Published: January 2024

The concentration of soluble fibrinogen derivatives (sfd) and protease and procoagulant activities were determined in cell-free supernatants of equine respiratory secretions obtained from horses with chronic pulmonary disease. The concentration of neutrophils was estimated from direct smears of the secretions. Lung specimens and smears of the secretions were evaluated for the presence of fibrin or fibrinogen by use of immunohistochemical methods.

Thirty-five of 80 specimens tested contained sfd. Respiratory secretions from horses with moderate or severe chronic pulmonary disease contained sfd more frequently than did secretions from mildly affected horses (P < 0.05). Respiratory secretions with vast numbers of neutrophils had significantly (P < 0.05) higher sfd concentrations than respiratory secretions with fewer neutrophils. Protease and procoagulant activities in respiratory secretion specimens were positively correlated with neutrophil content, clinical diagnosis, and sfd concentration.

Immunohistochemically, macrophages that stained for fibrin or fibrinogen were observed in direct smears of respiratory secretions from horses with moderate and severe chronic small airway disease, but not in smears from mildly affected horses. Fibrin or fibrinogen was detected in a few thickened alveolar septa from 10 horses with moderate or severe chronic small airway disease, but not in lungs from horses with mild or no evidence of chronic small airway disease. Fibrin or fibrinogen was detected in alveolar septa, granulomas, and on alveolar macrophages in lungs of all horses with chronic granulomatous and chronic bronchointerstitial pneumonia.

The presence of sfd in equine respiratory secretions may be an indicator of pulmonary inflammation.
Comparative blood characteristics of ranched and free-ranging American bison (Bison bison)
Authors: Sikarskie James G. , Schillhorn van Veen Tjaart W. , van Selm Gijsbertus , Kock Michael D.
Published: January 2024

Blood samples were obtained from 20 bison (Bison bison) from a ranch in northern lower Michigan, as well as from 20 free-ranging bison of the same sex and similar age from the Badlands National Park in South Dakota. Hematologic and serum biochemical values were determined. The values were comparable in both groups, except for those for bun, aspartate transaminase, and phosphorus, which were significantly (P < 0.001) higher in the ranched bison than in the free-ranging bison. These differences were attributed to nutritional effects. Impact of age on blood characteristics was assessed in the ranched bison only by comparing values from calves weighing less than 185 kg with those from bison weighing more than 185 kg. Calves had significantly (P < 0.001) higher values for phosphorus and rbc counts and lower total protein values than adults. Adult bison had higher eosinophil and neutrophil counts with lower numbers of lymphocytes, suggestive of a stress leukogram, whereas calves had the typical bovine neutrophil:lymphocyte ratio.
Chromogenic assay for equine plasminogen
Authors: Welles Elizabeth G. , Prasse Keith W. , Duncan Alexander
Published: January 2024

A functional assay for equine plasminogen was established, using urokinase as the activator, a synthetic chromogenic substrate, a computer-assisted centrifugal analyzer, and acidified/neutralized plasma. One documented effect of plasma acidification appears to be inactivation of alpha-2-antiplasmin. Intra- and interassay precision testing yielded coefficients of variation of 4.1% (n = 10) and 5.6% (n = 26), respectively. Plasminogen was stable in equine plasma stored up to 1 week at 4 C and up to 5 months at − 70 C. Plasminogen in nonacidified equine plasma was not activated by urokinase, streptokinase, tissue plasminogen activator, or tissue plasminogen activator plus soluble fibrin. Streptokinase also failed to activate plasminogen in acidified/neutralized equine plasma.
Experimentally induced Staphylococcus aureus mastitis in selenium-deficient and selenium-supplemented dairy cows
Authors: Erskine Ronald J. , Eberhart Robert J. , Scholz Richard W.
Published: January 2024

Ten Holstein cows were fed a selenium-deficient (SeD) diet containing 0.04 mg of Se/kg of dry matter for 3 months before and throughout their first lactation. A selenium-supplemented (SeS) group of 10 cows was fed an additional 2 mg of Se/head/d to increase dietary Se concentration of the dry matter to approximately 0.14 mg/kg of body weight. An intracisternal challenge exposure of 40 to 60 colony-forming units (cfu) of Staphylococcus aureus was administered into 1 or 2 quarters of the udder of each trial cow at about the twenty-second week of lactation. Blood Se concentration (μg/ml±sem) at the time of challenge exposure was 0.035±0.002 in SeD and 0.139±0.006 in SeS cows. Infections were established in 14/16 of the challenge-exposed quarters in SeD and 16/19 of the challenge-exposed quarters in SeS cows. The infection in 1 quarter of each Se group cleared without treatment by the end of the 8-week trial period.

Log10 peak bacterial concentrations in milk from infected SeD quarters (5.04±0.25 cfu/ml) were higher (P < 0.05) than those of infected SeS quarters (4.40±0.12 cfu/ml). Log10 peak somatic cell count (scc) in milk from infected SeD quarters (7.18±0.08 cells/ml) did not differ from that of SeS quarters (7.17±0.05 cells/ml). Peak bacterial concentrations were attained sooner (P < 0.05) in SeD quarters (9.5±4.0 days) than in SeS quarters (20.7±3.1 days). Similarly, peak scc were reached earlier (P < 0.05) in SeD (4.3±1.1 days) than in SeS quarters (13.3±3.8 days). The Se groups did not differ significantly with respect to peak milk concentrations of bovine serum albumin or IgGl. Throughout the 8-week trial, the Se groups did not differ significantly in milk bacterial concentration, scc, bovine serum albumin, or IgGl. Selenium status did not affect the percentage of challenge exposures resulting in infection, duration, or severity of experimentally induced S aureus mastitis.
Comparison of bile porphyrin concentrations in cattle and human beings with protoporphyria
Authors: Bloomer Joseph R. , Straka James G. , Hill Hazel , Weimer Mary K. , Ruth George R.
Published: January 2024

Blood and bile porphyrin concentrations were measured in cattle with protoporphyria and compared with those in human beings with the disease. Whereas the mean rbc porphyrin concentration in cattle was 18-fold greater than in human beings, the mean bile porphyrin concentration was only 78% greater. Sequential measurements over a 30-hour period in 1 animal with a bile fistula indicated that the ratio of total porphyrin to total bile acid in bile varied minimally. When the animal was given an iv infusion of taurocholate, the biliary excretion rate of porphyrin increased in parallel with that of bile acid, because of enhancement of bile flow.

Thus, in cattle with protoporphyria, the concentration of porphyrin in bile is low compared with that of porphyrin in rbc, in contrast with findings in human beings, and adequate amounts of bile acids are secreted to maintain efficient protoporphyrin excretion. This explains, in part, why hepatobiliary disease has not been observed in cattle with protoporphyria, but has been seen in human beings with the disease.
In vitro migration responses of neutrophils from cows and calves
Authors: Olson D. P.
Published: January 2024

The directional (chemotactic) and random migration activities of neutrophils from cows and newborn and 2-week-old calves were determined by use of the chemotaxis-under-agarose assay. Blood samples were stored for 2, 24, or 48 hours and at 4 or 25 C before testing. During the assay, cells were incubated at 17, 27, or 37 C.

The assay was found suitable for testing the directional and random migration activities of neutrophils from cattle. Directional migration of neutrophils was diminished (P ≤ 0.05) when cells were incubated at 17 or 27 C, compared with data from incubation at 37 C. Random migration of neutrophils was unaffected by test incubation temperature. Significant (P ≤ 0.05) differences were found between cows and calves regarding the percentage number and viability and the directional and random migration activities of neutrophils. Neutrophils from cows were adversely affected to a greater extent by prolonged sample storage times or low storage temperature than were neutrophils from calves. Results indicate that a sample storage time of up to 24 hours, a sample storage temperature of 25 C, and a test incubation temperature of 37 C provided optimal conditions for testing the migratory activities of neutrophils from cattle.
Induction of neutralizing antibodies against bovine leukosis virus in rabbits by vaccination with recombinant vaccinia virus expressing bovine leukosis virus envelope glycoprotein
Authors: Ohishi Kazue , Suzuki Hidemi , Maruyama Tadashi , Yamamoto Toshiko , Funahashi Shin-ichi , Miki Keizaburo , Ikawa Yoji , Sugimoto Masanobu
Published: January 2024

Three kinds of recombinant vaccinia virus (rvv)—mO-ha/ati, LO1-ha/ati and mO-ha/7.5kD—expressing bovine leukosis virus (blv) envelope glycoprotein (gp60) were constructed. The blv envelope gene of rvv mO-ha/ati and LO1-ha/ati or of rvv mO-ha/7.5kD was expressed under control of the promoter of A-type inclusion body (ati) protein gene of cow-pox virus or vaccinia virus 7.5-kD protein gene, respectively. The vaccinia virus strain, LC16mO, was used as vector for rvv mO-ha/ati and mO-ha/7.5kD, and strain LO-1 was used for rvv LO1-ha/ati. Strains LC16mO and LO-1 are attenuated vaccine virus strains originating from the Lister original vaccinia virus.

All 3 kinds of constructed rvv expressed gp60 in cultured rabbit kidney cells after infection; mO-ha/ati expressed more antigen than did mO-ha/7.5kD. Rabbits vaccinated with rvv produced considerable antibody capable of inihibiting syncytium formation, as well as antibody with virion-binding ability. The rvv that used ati promoter induced higher antibody titer than did the rvv that used 7.5-kD promoter. Results indicate that blv gp60 is responsible for induction of neutralizing antibodies that suppress in vitro formation of syncytia among blv-infected cells.

Applicability of rvv, especially those using ati promoter, was evaluated in a vaccine against bovine leukosis.
Temporal appearance of structural and nonstructural bluetongue viral proteins in infected cells, as determined by immunofluorescence staining and flow cytometry
Authors: Whetter L. E. , Gebhard D. H. , MacLachlan N. J.
Published: January 2024

The temporal appearance of 4 viral proteins was detected in bluetongue virus (btv)-infected Vero cells by indirect immunofluorescence staining with monoclonal antibodies (MAb) to btv structural proteins VP2 and VP7 and nonstructural proteins NS1 and NS2. Bluetongue viral proteins were detected at distinct intervals after inoculation of Vero cells; VP7 was first detected 3 hours after inoculation, NS1 and NS2 at 5 hours after inoculation, whereas VP2 was not detected until 8 hours after inoculation. Patterns of fluorescence varied with the fixative used, but each MAb induced a distinct pattern of fluorescence in infected cells.

Flow cytometry, which was used with each of the 4 MAb, proved to be an accurate and sensitive method of detecting btv-infected P3 mouse myeloma cells. The temporal appearance of each viral protein in btv-infected P3 cells was similar to that detected in btv-infected Vero cells. Advantages of flow cytometry over conventional immunofluorescence staining to detect btv-infected cells included: (1) enumeration of the proportion of infected cells in a population; (2) further characterization of infected cells, including estimates of their viability; and (3) computer-assisted storage and analysis of data obtained.
Cardiovascular and respiratory effects of inspired oxygen fraction in halothane-anesthetized horses
Authors: Cuvelliez Sophie G. , Eicker Steven W. , McLauchlan Charlene , Brunson David B.
Published: January 2024

Anesthesia of equids is associated with pulmonary dysfunction. Cardiovascular and respiratory effects of inhalation anesthetic agents and duration of anesthesia have been studied, using oxygen as the carrier gas. To our knowledge, the effects of inspired oxygen have not been determined. We studied the cardiovascular and respiratory effects of 2 inspired oxygen fractions (0.30 and > 0.85) in 5 laterally recumbent, halothane-anesthetized horses. Mean systemic arterial blood pressure, cardiac output, central venous pressure, pulmonary arterial pressure, arterial pH, and arterial base excess were similar in horses of the 2 groups during 4 hours of anesthesia at constant end-tidal halothane concentration. End-tidal partial pressure of CO2, arterial partial pressure of CO2 and O2, and alveolar-to-arterial O2 tension difference were greater in horses exposed to the higher oxygen concentration. On the basis of the data obtained, we suggest that greater hypoventilation and ventilation/perfusion mismatch occur when horses are breathing high-oxygen fraction. Arterial partial pressure of O2 was not different between the 2 groups of horses after they were disconnected from the anesthesia circuit and allowed to breathe room air. Horses recovered from anesthesia without complications.
Electromyographic evaluation of the external urethral sphincter during cystometry in male cats
Authors: Sackman Jill E. , Sims Michael H.
Published: January 2024

Electromyographic (emg) evaluation of the external urethral sphincter (eus) was conducted during cystometry in 11 adult male cats sedated with xylazine and ketamine. A percutaneously placed antepubic catheter was used for bladder infusion and recording intravesicular pressures during cystometrography (cmg). A fine-wire electrode was placed percutaneously into or near the eus for recording emg during cmg. The bladder was infused with sterile 0.9% NaCl solution at a rate of 2 to 3 ml/min until a detrusor reflex was initiated. Intravesicular pressures at the onset of infusion, immediately prior to micturition, at the onset of urine flow, and at the maximal voiding pressure were recorded. The time from infusion to micturition, from opening pressure to return to baseline, and from the beginning to the end of the cmg were also recorded. The total volume of 0.9% NaCl solution infused and the residual bladder volume after micturition were also measured. Recordings were replicated once during each trial in all cats, and trials were replicated once approximately 1 week later in 4 cats.

Micturition patterns were characterized by slight to moderate eus emg activity during vesicular filling, with reduction in activity during emptying. Maximal emg activity was recorded at the completion of the reflex and was associated with pulsatile expulsion of small amounts of urine. The simultaneous recording of cmg and eus emg with fine-wire electrodes was simple and reliable for assessing the neuromuscular integrity and synchrony of detrusor and eus muscles. There were no significant differences in variables between recordings within trial 1, but there were differences (P ≤ 0.05) between trials for pressure at the onset of urine flow and maximal voiding pressure.
Pharmacokinetics and metabolic inertness of doxycycline in young pigs
Authors: Riond Jean-Luc , Riviere J. Edmond
Published: January 2024

The disposition of doxycycline hyclate after iv administration of 20 mg/kg of body weight was studied in 6 pigs. Median elimination half-life, estimated in 4 pigs, was 3.92 hours. Mean (± sem) total body clearance was 1.67 ± 0.18 ml/min/kg, and mean apparent volume of distribution at steady state was 0.53 ± 0.04 L/kg. In 2 pigs, secondary peaks in the logarithmic serum concentration-time profile suggested discontinuous enterohepatic cycling, and precluded using these pigs in the pharmacokinetic analysis. The extent of doxycycline binding to serum protein was 93.1 ± 0.2%. Serum or urine from 3 of the pigs was analyzed by use of photodiode array detection and mass spectrometry of a high-performance liquid chromatographic column effluent. These procedures documented lack of doxycycline biotransformation in pigs. It is concluded that, despite an elimination half-life shorter than that reported in other species, doxycycline may be a valuable antimicrobial drug for use in swine practice, pending the development of appropriate formulations.
Development and infectivity of Anaplasma marginale in Dermacentor andersoni nymphs
Authors: Kocan Katherine M. , Yellin Theodora N. , Claypool P. L. , Barron Selwyn J. , Ewing S. A. , Hair Jakie A.
Published: January 2024

The development of Anaplasma marginale was studied in Dermacentor andersoni nymphs after they had fed on a calf with ascending Anaplasma infection. Gut tissues were collected on day 4 of tick feeding, from newly replete (fed) nymphs and on postfeeding days (pfd) 5, 10, 15, 20, and were processed for light and electron microscopy to determine density of A marginale colonies. Homogenates of gut tissues were prepared from nymphs collected on the same days and inoculated into susceptible, splenectomized calves to test for infectivity. Anaplasma colonies were detected in gut cells on pfd 5, 10, 15, and 20. Although colony density appeared to be higher on pfd 10 and 15, differences were not significant. Nymphal type-1 colonies were detected in highest numbers on pfd 5 and 10, transitional colonies were seen in highest numbers at pfd 10 and 15, and nymphal type-2 colonies were observed only on pfd 20. Gut homogenates that were collected from ticks at 4 days of feeding, when newly replete, and on pfd 20 caused anaplasmosis when injected into susceptible calves, but homogenates made from ticks collected on pfd 5, 10, and 15 were not infective. The data indicate that of the colony types of A marginale that develop in replete nymphs, nymphal type-1 and transitional colonies may contain organisms that are not infective for cattle.
Amplitude and latency characteristics of spinal cord motor-evoked potentials in dogs
Authors: Cook J. R. , Konrad P. E. , Tacker W. A.
Published: January 2024

The motor-evoked potential can be reliably recorded in anesthetized dogs by use of percutaneous placement of active recording electrodes near the dorsal lamina of the vertebral column. Two types of responses were observed in this study; short (< 5.5 ms at T9-10)- and long (> 5.8 ms at T9-10)-latency waves. Short-latency waves are larger in amplitude and appear with higher stimulus intensities than do long-latency waves. Short-latency waves are conducted at > 80 m/s and may not reflect pyramidal tract activation. The safety of using higher intensity stimuli to generate short-latency waves has not been determined.
Plasma, tissue, and urine carnitine concentrations in healthy adult cats and kittens
Authors: Jacobs Gilbert , Keene Bruce , Cornelius Larry M. , Rakich Pauline , Shug Austin
Published: January 2024

Mean carnitine concentrations ([carnitine]) were higher (P < 0.05) in adult cats than in kittens for skeletal muscle (total and free carnitine), myocardium (free carnitine), and urine (total and free carnitine). The free/total carnitine ratio was lower (P < 0.05) in kittens than in adults for liver, myocardium, and urine. Carnitine concentrations were similar between genders in kittens, but in adult cats, [carnitine] in plasma (total, free, and esterified carnitine) and liver (total and free carnitine) were higher (P < 0.05) in female than in male cats. Total and free plasma [carnitine] were correlated to total and free liver [carnitine], respectively. Skeletal muscle [carnitine] was not correlated to plasma [carnitine]. Correlations in [carnitine] between plasma and myocardium, kidney, or urine were inconsistent.
Fetal membranes and ancillary structures of llamas (Lama glama)
Authors: Fowler Murray E. , Olander Harvey J.
Published: January 2024

The placenta of llamas is epitheliochorial, with patchy areas of dense folded papillation serving as the placentome. The amnion of the full-term placenta is closely adhered to either the allantois or the chorion and remains with these structures at the time of parturition.

Llamas and alpacas, like dromedaries, have an extra fetal membrane that is derived from the epidermis of the fetus. In association with the watery amniotic fluid of llamas, the epidermal membrane is slippery, facilitating delivery of the fetus.
Use of inflammatory cell activities in bovine milk to diagnose mastitis
Authors: Lilius Esa-Matti , Pesonen Ullamari
Published: January 2024

The activity of leukocytes, determined by chemiluminescence (cl) emission, was compared with the somatic cell count (scc) in 4,883 quarter-milk samples from 132 dairy cows. The presence of bacteria was determined by bacteriologic culture of samples in which scc and cl were high. Chemiluminescence was measured with an automated illuminometer system at 37 C after separating the leukocytes from milk by allowing them to adhere to cotton-wool swabs. Chemiluminescence emission was induced by opsonized zymosan and enhanced by luminol. After luminol and zymosan were added to the measuring vials containing the swabs, cl emission increased rapidly, reaching its maximum usually at about 15 minutes of reaction time, and decreasing slowly thereafter. In general, good correlation was found between cl and scc (r = 0.876; P ≤ 0.001; n = 4,883). Even milk samples with low scc gave reliably measurable cl signals. Minor pathogens in the milk caused about a sevenfold increase in both scc and cl, whereas major pathogens caused 14- and 25-fold increases in scc and cl, respectively. The diagnostic situation that requires both sensitivity and specificity to be at least 90% was attained only by the cl assay for major pathogens. These results suggest that the measurement of milk leukocyte activity by cl assay applies well to the diagnosis of mastitis, and has the potential to become a large-scale laboratory test, as well as a simple cowside test.
Comparison of two antigens for use in an enzyme-linked immunosorbent assay to detect African swine fever antibody
Authors: Pastor M. J. , Arias M. , Escribano J. M.
Published: January 2024

Two African swine fever virus (asfv) antigens were tested for use in an elisa to detect antibody to asfv. Antigens used were the cytoplasmic soluble fraction (cs-p) of infected cells grown in the presence of porcine serum and the semipurified viral structural protein VP73 (svp73). Both antigens were tested by elisa against 72 sera obtained during several asf field episodes and from asfv- inapparent carriers. Of the 72 sera, only 2.8% had positive results by elisa against cs-p antigen; 60% of positive-reacting sera (to both antigens) had higher elisa values when the cs-p antigen was used. Samples (with positive results) that reacted only to cs-p antigen had results confirmed by immunoblot analysis. Such sera reacted against asfv-infection proteins IP25, IP25.5, and IP30, but not against IP73.

In time-course experiments to detect appearance of asfv-antibodies in infected miniature pigs, antibodies were detected by immunoblot analysis on postinoculation day (pid) 8. At that time, only the polypeptides IP25, IP25.5, IP30, and IP31 were recognized; IP73 and IP12 were first detected 3 and 4 days later, respectively. In the same experiments, asfv antibodies were detected by elisa, using cs-p or svp73 antigens, on pid 7 and 9, respectively. These results could explain the percentage of sera not having positive results by elisa using svp73 antigen, if the sera were obtained from asfv-infected pigs during the first days of infection before induction of antibody response against the IP73 protein. This feature makes the use of cs-p antigen advantageous in early serologic detection of asfv-infected pigs.
Lack of formyl-methionyl-leucyl-phenylalanine receptors on porcine neutrophils
Authors: El-Awar Faisal Y. , Ochs Duane L. , Pyle Robert H. , Misra Hara P.
Published: January 2024

The response of blood neutrophils to the chemotactic peptide formyl-methyl-leucyl-phenylalanine varies among species. Our results indicate that this peptide does not activate the respiratory burst of porcine neutrophils. Specifically, concentrations ≤ 10-6M did not cause production of either superoxide or hydrogen peroxide. Studies designed to delineate the biochemical deficit responsible for these results indicated that these cells do not express specific chemotactic peptide receptors on the external surface of the plasma membrane. Although these data do not rule out the possibility that internal stores of chemotactic peptide receptor exist, attempts to induce expression of the receptor by priming the cells with either lipopolysaccharide or calcium ionophore were unsuccessful.
Correlation of sensory electroneurographic recordings and myelinated fiber diameters of the superficial peroneal nerve of dogs
Authors: Niederhauser Urs B. , Holliday Terrell A. , Hyde Dallas M. , McQuarrie Allan D. R. , Fisher Linda D.
Published: January 2024

The compound nerve action potential (cnap) of the superficial peroneal nerve of dogs was investigated to determine: (1) the influence of the stimulation technique on the configuration of the cnap, with particular attention to late components; (2) the fiber diameter (fd) distribution; and (3) the relationship between fd distribution and cnap configuration, by reconstruction of cnap made on the basis of fd distributions.

The cnap were evoked in 9 dogs under halothane anesthesia by 2 stimulation methods: percutaneous needle electrode stimulation and direct stimulation of the exposed superficial peroneal nerve. Recordings were made with percutaneous needle electrodes. Full nerve cross sections of 7 superficial peroneal nerves were prepared for fd morphometric analysis. Reconstruction of cnap were made on the basis of the fd distributions.

Late components of the cnap could be evoked with either stimulation method, but only with a stimulus intensity of 3 to 5 times maximal for the main (early) component of the cnap. The fd histograms of 7 analyzed nerves had bimodal distribution. In 5 nerves, peaks were at 4.2 to 4.5 μm and 9.0 to 10.0 μm, with 60% of the fibers in the small-diameter group. In 2 nerves with lower maximal conduction velocities, peaks were shifted toward smaller values.

The cnap reconstructions made by use of fd data closely resembled actual recordings when a fifth-order polynomial function was applied to the relationship between nerve conduction velocity and fd. Reconstructions made by use of 1 or 2 linear functions did not accurately resemble actual recordings.

The results indicate clinical sensory electroneurographic recordings can provide accurate information regarding both large- and small-diameter fibers, if adequate stimulus intensities are used. To understand the recorded potential more completely, further studies are needed to determine the effects of volume conduction on configuration of the cnap. It should then be possible to estimate fd distributions even more accurately by analyzing cnap of normal nerves, or of diseased nerves in which the normal relation between fd and conduction velocity is preserved.
Immune response to pulmonary injection of Pasteurella haemolytica-impregnated agar beads followed by transthoracic challenge exposure in goats
Authors: Purdy Charles W. , Straus David C. , Livingston Charles W. , Foster Gene S.
Published: January 2024

A method of inducing Pasteurella haemolytica serotype 1 (Ph1) lung infection in goats, using low numbers of bacteria and without impairing host immunity, was developed. Two trials were conducted. Results of trial 1, using 10 principals (Ph1 agar beads) and 6 controls (agar beads alone), indicated that Ph1 organisms imbedded in agar beads could survive host lung defenses for 32 days. Results of trial 2 indicated that lung immunity in the inoculated goats (principals) was high and they were more protected than controls against a transthoracic challenge of Ph1 (1.18 × 107 colony-forming units) injected into a lung of each goat on posttreatment day 35. When comparing challenge-exposed principals with controls, the controls developed rectal temperatures above normal for a longer time, duration of anorexia was longer, and signs of depression were seen. The controls developed large areas of consolidated lung tissue, more Ph1 isolates were recovered from nasal turbinates and lung tissue, and higher Ph1 concentrations were found in the lungs. The serum Ph1 indirect hemagglutination antibody titers in the principals of both trials increased, compared with titers in controls. Principal goats in ferial 2 had higher Ph1 indirect hemagglutination antibody titers after injection of Phi-impregnated agar beads and less severe lung lesions after challenge exposure than did controls. The small pneumonic consolidated lesions in the principals, compared with extensive lesions in controls after Ph1 challenge exposure, indicated a high degree of immunity after exposure to Ph1 organisms imbedded in agar beads.
Comparative pathogenicity of selected bovine viral diarrhea virus isolates in gnotobiotic lambs
Authors: Jewett C. J. , Kelling C. L. , Frey M. L. , Doster A. R.
Published: January 2024

The infectivity and pathogenicity of selected bovine viral diarrhea virus (bvdv) isolates were determined in gnotobiotic, colostrum-deprived neonatal lambs. Five-day-old cesarean-derived gnotobiotic lambs were exposed to 1 of 10 bvdv. isolates via aerosol suspension. These isolates were from tissues or secretions of calves or lambs affected with respiratory tract disease, weak neonatal calves, aborted bovine fetuses, or reference Singer or Draper bvdv. The pathogenicity of each isolate, relative to the others, was evaluated in lambs by measurement of the neutralizing antibody response, virus isolation from nasal secretions or tissues, and postmortem lesions. The bvdv isolates varied in their infectivity and pathogenicity. Singer, the cytopathic reference strain, was the most lymphotrophic isolate and stimulated the greatest neutralizing antibody response. Encephalitis was the most consistent lesion observed and was used as the final determinant of relative pathogenicity of the viruses. The most neuropathogenic isolates were the 2 viruses originating from lambs affected with respiratory tract disease, the 2 weak neonatal calf isolates, and 1 isolate from an aborted bovine fetus. The least pathogenic isolates were the 2 reference isolates, Draper and Singer; the 2 mucosal disease isolates; and 1 isolate originating from an aborted bovine fetus.
Congenital malformations in sheep resulting from in utero inoculation of Cache Valley virus
Authors: Chung S. I. , Livingston C. W. , Edwards J. F. , Gauer B. B. , Collisson E. W.
Published: January 2024

Serologic evidence indicated that an episode of congenital abnormalities in sheep was caused by Cache Valley virus (cvv), a bunyavirus indigenous to the United States. To determine the teratogenic potential of cvv in sheep, fetuses were infected in utero between 27 and 54 days of gestation with an isolate (CK-102) obtained in 1987 from a sentinel sheep in San Angelo, Texas. The dams of these fetuses were euthanatized between 28 and 75 days after inoculation, and the fetuses were examined for malformations. Twenty-eight of 34 fetuses had congenital abnormalities, including arthrogryposis, hydranencephaly, mummification, reabsorption, and oligohydroamnion. Virus was isolated from the allantoic fluid of 11 of 17 fetuses euthanatized at less than 70 days of gestation. The virus-positive fetuses, which were all negative for cvv-neutralizing antibody, had lesions ranging from none to severe arthrogryposis and hydranencephaly. Virus was not recovered from the allantoic fluid of fetuses after 76 days’ gestation when cvv-specific antibody could be detected in 5 of 8 fetuses examined. The 2 fetuses infected on days 50 and 54 of gestation appeared normal and 1 had antibody to cvv.
Horseradish peroxidase study of the location of extrinsic efferent and afferent neurons innervating the colon of dogs
Authors: Hudson L. C.
Published: January 2024

The abdominal portion of the colon of 13 clinically normal dogs was divided into 5 regions (ascending, transverse, left colic flexure, proximal descending, and distal descending), and each region was injected with 30 mg of horseradish peroxidase (hrp). The injected colonic region, brain stem, L7-Cd1 portion of the spinal cord, sympathetic trunk ganglia, celiacomesenteric ganglia, caudal mesenteric ganglion, pelvic plexi, distal vagal (nodose) ganglia, and Ll-Cdl spinal ganglia were obtained at postinjection hour 48, sectioned, and processed by use of the tetramethylbenzidine method. The entire length of the colon was found to be under extrinsic influence of the parasympathetic nucleus of cranial nerve X (px), with the largest average number of labeled cells resulting from injection of the ascending colon. It was also indicated that the entire colon is under extrinsic influence of the sacral portion of the spinal cord because the pelvic ganglia (second-order neurons) of the pelvic plexi contained labeled cells for all colonic regions. The largest average number of labeled cells in pelvic ganglia was seen after injection of the distal portion of the descending colon. Only after injection of the distal portion of the descending colon were labeled cells found in the S1-S3 portion of the spinal cord. Labeled cells in the px, spinal cord, and pelvic ganglia were found bilaterally. Although the entire abdominal portion of the colon appears to be influenced by cranial and sacral parasympathetic preganglionic (via pelvic ganglia) neurons, the relative importance of the 2 areas seems to be reversed between the ascending colon and distal portion of the descending colon. Sympathetic postganglionic innervation was located in the celiacomesenteric ganglion, caudal mesenteric ganglion, and, inconsistently, in sympathetic trunk ganglia. Sensory innervation for all colonic regions was found bilaterally in the distal vagal ganglia, and in 2 groups of spinal ganglia—a cranial group of LI to L5 and a caudal group of S1 to Cd1 ganglia.

It has been reported in the literature that the left colic flexure is subject to colonic perforation in dogs with spinal cord disease treated with corticosteroid administration, but a direct, anatomic reason for this site of susceptibility was not found during this study. It is possible that the left colonic flexure represents the most proximal portion of colon detrimentally affected by loss of sacral influence, because the relative importance of vagal and sacral parasympathetic innervation appears to shift along the length of the colon.
Use of laser Doppler flowmetry to determine blood flow in and viability of island axial pattern skin flaps in rabbits
Authors: Lanthier T. , Miller C. , McDonell W. N. , Yager J. A. , Roth J. H.
Published: January 2024

Perfusion and viability of island axial pattern skin flaps were tested in 37 healthy New Zealand white rabbits, using laser Doppler monitoring of blood flow in the capillary loops and the subpapillary plexus of the dermis. Skin flaps, selected on the basis of the caudal superficial epigastric vein and artery, were lifted and replaced in their original locus after selective occlusion of their vascular pedicles. Subjects were allotted into groups: control group (n = 10); arterial occlusion (n = 7); venous occlusion (n = 10); and arterial and venous occlusion (n = 10). The rabbits were monitored from 48 hours before surgery until euthanasia 48 to 72 hours after replacement of the flap. Flap viability was assessed on a clinical basis, using a comparative scoring method based on a numeric scale. The degree of necrosis in histologic sections was evaluated, using a scoring system. Laser Doppler measurements were obtained on 3 consecutive days before surgery, to establish the normal basal blood flow in the skin. Post-surgical measurements were obtained at 2-hour intervals for the first 8 hours and at 24, 48, and 72 hours after surgery. Measurements of basal blood flow varied significantly (P < 0.05) from site to site on the surface of individual flaps and over time. When laser Doppler flowmetric (ldf) measurements from 6 sites on a flap were used as a measure of laser Doppler flow for the total flap, there was no significant difference between contralateral flap areas outlined on the abdomen of the rabbits. Temporal variations over 3 days for each rabbit or among rabbits were not significant.

The ldf measurements detected acute vascular occlusion when compared with the controls, and were able to differentiate between control and arterial occlusion groups, control and venous occlusion groups, control and arterial and venous occlusion groups, arterial and venous occlusion groups, venous and arterial and venous occlusion groups (P < 0.05), but not between arterial and arterial and venous occlusion groups. Evaluation of ldf values at 4 hours proved to be a better predictor than clinical assessment at 4 or 8 hours in evaluating skin flap viability.
Preliminary investigation of alterations in blood viscosity, cellular composition, and electrophoresis plasma protein fraction profile after competitive racing activity in Thoroughbred horses
Authors: Coyne C. P. , Carlson Gary P. , Spensley Michael S. , Smith Joseph
Published: January 2024

In this preliminary investigation, various hematologic variables potentially influential in determining the degree of blood viscosity were evaluated in 10 Thoroughbred horses subjected to competitive acute running exercise. Following completion of sprints over a distance of 1.25 miles, mean percent (± sd) increases in pcv (38.3 ± 12.9%), rbc (47.8 ± 15.3%), and rouleaux index (232.7 ± 176.8%) were recognized. Simultaneous increases in total plasma protein (28.3 ± 5.31%), serum albumin (26.7 ± 6.80%), α1-globulin (60.0 ± 49.0%), α2-globulin (25.5 ± 27.9%), β1-globulin (46.7 ± 21.1%), (32-globulin (35.0 ± 50.6%), γ1- and 2-globulins (38.7 ± 29.6%), and plasma fibrinogen (12.5 ± 10.4%) concentrations increased simultaneously. Horses also had consistent decreases in albumin:globulin ratio (- 10.0 ± 7.43%). Alterations in these hematologic values after acute running exercise in Thoroughbred horses accompanied increases in serum (69.3 ± 39.7%), plasma (39.7 ± 11.9%), and blood (134.7 ± 55.3%) viscosity.
Antimicrobial resistance in streptococcal species isolated from bovine mammary glands
Authors: Brown M. B. , Scasserra A. E.
Published: January 2024

Streptococcal species isolated from dairy cows with clinical mastitis were obtained from mastitis research workers in Florida, Louisiana, New York, Vermont, Washington, and West Virginia. Seventy-one streptococcal isolates were tested, including 39 strains of Streptococcus agalactiae, 21 strains of S dysgalactiae, and 11 strains of S uberis. The minimal inhibitory concentration of erythromycin, lincomycin, oxytetracycline, penicillin, spectinomycin, streptomycin, and tetracycline was determined for each isolate. Differences were not detected among strains with respect to geographic origin. None of the strains was resistant to penicillin. Lincomycin was the next most effective antimicrobial, with only 2 resistant strains of each streptococcal species. There were no differences among the streptococcal species with respect to resistance to either penicillin or lincomycin. Streptococcus uberis was more likely to be resistant to erythromycin than were S agalactiae and S dysgalactiae (P < 0.02). Streptococcus agalactiae and S uberis had similar distributions for resistance to oxytetracycline, tetracycline, spectinomycin, and streptomycin. Strains of S dysgalactiae were more likely to have intermediate resistance to oxytetracycline and streptomycin than were strains of S agalactiae and S uberis, which were highly resistant to oxytetracycline and streptomycin (P < 0.001). Differences were not detected among the streptococcal species with respect to resistance to spectinomycin. Resistance to multiple antimicrobials was observed in all streptococcal species tested. Although S dysgalactiae appeared to have a greater percentage of strains (73%) that were resistant to multiple antimicrobials than did S agalactiae (31%) or S uberis (45%), differences were not statistically significant.
Effect of diet on struvite activity product in feline urine
Authors: Buffington C. A. , Rogers Q. R. , Morris J. G.
Published: January 2024

Groups of male specific-pathogen-free cats were fed a basal, purified diet (A), with or without 0.45% added magnesium (MgCl2, diet B; MgO, diet C) or 1 of 2 commercial diets (D, E). Urine samples collected for 48 hours after 2 weeks of feeding were analyzed for calcium, magnesium, sodium, potassium, ammonium, sulfate, phosphate, oxalate, and citrate content. Concentrations were used to calculate the negative logarithm of the struvite activity product (pSAP), using a microcomputer-based program for calculation of supersaturation of the urine with crystal solutes. The pSAP value for all samples also was hand calculated by use of an equation.

Consumption of diet B caused a significant (P < 0.05) increase in urine calcium concentration. Total urine phosphate concentration was lower in urine from cats fed diets A, B, or C than in urine from cats fed diets D or E. For the various diets, urine PO4-3 was: 5.3 μM for diet A; 6.3 μM for diet C; 0.9 μM for diet E; 36 nM for diet D, and 0.5 nM for diet B. Consumption of diets B and C caused significant increases in urine magnesium concentration (53.1 nM and 49.1 mM, respectively). Ammonium ion concentration was highest in urine from cats fed diets B and D, 116.2 mM and 100.3 mM, respectively. When the pSAP, hand-calculated assuming ionic strength u = 0.2, was regressed on that calculated by use of the microcomputer program, the coefficient of determination was 0.96 (P ≤ 0.01).
In vitro characteristics of normal and dystrophic skeletal muscle from dogs
Authors: Valentine Beth A. , Chandler Suzanne K. , Cummings John F. , Cooper Barry J.
Published: January 2024

Expiants were prepared from skeletal muscle tissue from 5 nondystrophic pups and from 5 pups with X-linked muscular dystrophy; pups were 2 to 17 weeks old. A serial reexplant method resulted in optimal cell density with minimal fibroblast growth. Cultures were examined daily by use of phase-contrast microscopy; differentiated (post-fusion) cultures were examined by electron microscopy. Moderate nuclear pleomorphism and cell clustering were observed in cultures of normal and dystrophic muscle cells. Cultures were maintained to 27 days after plating. Minimal myofilament synthesis was observed in multinucleate cells from nondystrophic and dystrophic pups, but spontaneous contraction of myotubes was not observed during this period. Differences in growth, fusion, or differentiation of myogenic cells into multinucleate cells and myotubes were not found between dystrophic and normal muscle.