bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative aspects and sex differentiation of plasma sulfamethazine elimination and metabolite formation in rats, rabbits, dwarf goats, and cattle
Authors: Witkamp R. F. , Yun H-I. , van't Klooster G. A. E. , van Mosel J. F. , van Mosel M. , Ensink J. M. , Noordhoek J. , van Miert A. S. J. P. A. M.
Published: January 2024

Plasma disposition and urinary recovery of sulfamethazine (smz), its N4-acetylated metabolite (N4AcSMZ), and 2 of its hydroxylated metabolites—5-hydroxysulfamethazine (5OHSMZ) and 6-hydroxymethylsulfamethazine (6CH2OHSMZ)—were determined in either sex of 4 animal species: rats, dwarf goats, rabbits, and cattle. Rats, rabbits, and dwarf goats had significant (P < 0.01) sex difference in smz plasma clearance. Male rats had higher plasma clearance than did female rats, and excreted higher amounts of the hydroxy metabolites and lower amounts of N4AcSMZ. The N4AcSMZ metabolite was predominant in plasma and urine of rabbits. Male rabbits had higher plasma clearance than did female rabbits, but differences in metabolite profile were not apparent. With regard to plasma smz elimination, the situation in goats was opposite to that in rats. Male goats had considerably lower clearance than did female goats. This was associated with a lower hydroxylation rate in males. Plasma half-life of smz in cows was lower than that in bulls, probably because of a smaller distribution volume in cows. Compared with elimination via urine, elimination via milk was negligible in cows. Significant differences in metabolite profiles were not found between bulls and cows. Similar to those in rats and mice, hormone-dependent xenobiotic metabolic pathways may exist in other species. Depending on species and xenobiotic compound residue concentrations of xenobiotics, their metabolites, or both may differ with sex of the animal, or may be altered after treatment with anabolic hormones.
Effect of calf age and Salmonella bacterin type on ability to produce immunoglobulins directed against Salmonella whole cells or lipopolysaccharide
Authors: Roden Lin Da , Smith Bradford P. , Spier Sharon J. , Dilling George W.
Published: January 2024

A commercially available Salmonella bacterin was administered to Holstein calves starting at 1 to 19 weeks of age. Serum samples were obtained before administering bacterin and at 2-week intervals thereafter. An elisa with Salmonella dublin lipopolysaccharide (lps) or S dublin whole cells as antigen, was used to measure specific IgG and IgM responses. Antibody responses to lps were not detected from calves < 12 weeks old inoculated with killed bacterin. Immunoglobulin responses to whole-cell antigen were detected from all age groups of calves inoculated with the same killed Salmonella bacterin. Calves < 11 weeks old are able to produce immunoglobulins to some whole-cell antigens, but are unable to produce anti-lps immunoglobulins when inoculated with killed Salmonella bacterin. This age-related response to killed Salmonella antigens may account, in part, for increased susceptibility to salmonellosis in calves < 12 weeks old. In comparison to the response for killed antigen, 8 calves given modified-live aromatic-dependent S dublin bacterin at 1 to 3 weeks of age had detectable anti-lps immunoglobulins after immunization, although the response was not as rapid and was of a lesser magnitude than that of older calves given killed Salmonella bacterin.
Effects of furosemide and pentoxifylline on blood flow properties in horses
Authors: Gear Raymond J. , Weiss Douglas J. , Burris Steven M. , Smith Clark M.
Published: January 2024

The effects of furosemide and pentoxifylline on blood flow properties in horses were investigated. Hematologic and rheologic changes were examined in 4 horses before and 3 minutes after administration of epinephrine (1 mg, iv). The next day, hemorheologic changes were determined before and 3 hours after administration of furosemide (1 mg/kg of body weight, im), and after administration of epinephrine at the sampling at 3 hours. Hematologic and rheologic changes were evaluated weekly in 3 horses given pentoxifylline (8.5 mg/kg, q 12 h, po) for 28 days. In addition, hemorheologic responses to epinephrine were determined on days 0, 14, and 28 of pentoxifylline treatment. Neutrophil filtration studies were also performed 2 hours after iv administration of pentoxifylline (8.5 mg/kg).

Postepinephrine values for pcv, rbc and wbc counts, and blood viscosity were greater than preepinephrine values. Erythrocyte sedimentation rates decreased after epinephrine, whereas rbc filterability did not change. Treatment with furosemide was associated with increases in mean rbc hemoglobin concentration and blood viscosity. Filterability of rbc did not change. Treatment with pentoxifyllie resulted in an increase in rbc filterability and erythrocyte sedimentation rate and a decrease in pcv; however, mean values for hematocrit and rbc count did not change. Treatment with pentoxifylline did not result in a change in resting blood viscosity, but markedly reduced the postepinephrine increase in blood viscosity. Neither iv nor orally administered pentoxifylline had an effect on neutrophil filtration. It was concluded that pentoxifylline has beneficial effects on rbc filterability and postepinephrine changes in blood viscosity, which may contribute to improvements of microcirculatory blood flow. In addition, furosemide may exacerbate exercise-associated hyperviscosity in horses.
Platelet aggregation in dogs after sedation with acepromazine and atropine and during subsequent general anesthesia and surgery
Authors: Barr Stephen C. , Ludders John W. , Looney Andrea L. , Gleed Robin D. , Erb Hollis N.
Published: January 2024

Platelet aggregation and adenosine triphosphate (atp) release were measured by use of the impedance method in blood samples obtained from 25 adult female Beagles before and after sedation with acepromazine (0.13 mg/kg of body weight) and atropine (0.05 mg/kg), and during general anesthesia. General anesthesia was induced by iv administration of thiamylal (average dosage, 2.1 mg/kg; range, 1.2 to 4.2 mg/kg) and was maintained with halothane in oxygen. Samples of jugular venous blood were obtained from each dog, using citrate as anticoagulant. Platelet count was done on each sample. Platelet aggregation and atp released from the aggregating platelets were measured within 2.5 hours of sample collection, using a whole-blood aggregometer. Adenosine diphosphate (adp) or collagen was used as aggregating agent. For each aggregating agent, platelet aggregation and atp release were measured over 6 minutes. After sedation with acepromazine and atropine, significant (P < 0.01) reduction was observed in platelet count (from median values of 341,000 cells/μl to 283,000 cells/μl) and in the ability of platelets to aggregate in response to adp (from 14.0 to 7.0 Ω). During the same period, maximal release of atp in response to collagen also was reduced (from 5.56 μmol to 4.57 μmol; P < 0.01); however, this difference ceased to be significant when atp release was normalized for platelet count. During general anesthesia and surgery (200 minutes after sedation), platelet count and aggregation responses to adp and collagen had returned to presedation values. None of the dogs in this study appeared to have hemostasis problems during surgery.

In conclusion, sedation with acepromazine and atropine induces measurable inhibition of adp-induced platelet aggregation that resolves during subsequent general anesthesia and surgery. Transient inhibition of platelet aggregation is not manifested by a change in gross hemostasis during surgery.
Effect of treatment with erythromycin and rifampin during the acute stages of experimentally induced equine ehrlichial colitis in ponies
Authors: Palmer J. E. , Benson C. E.
Published: January 2024

Sixteen healthy ponies were inoculated iv with Ehrlichia risticii-infected P388D1 mouse monocytes. Of the 16 ponies, 15 developed clinical signs of equine ehrlichial colitis. Twenty-four hours after onset of fever (rectal temperature > 38.8 C), 7 ponies were treated with 25 mg of erythromycin stearate/kg of body weight and 10 mg of rifampin/kg, given orally every 12 hours for 5 days. The remaining 8 ill ponies served as nontreated controls. All ponies were observed for progression of clinical signs typical of equine ehrlichial colitis. Within 12 hours of initiation of treatment, 4 of the 7 treated ponies had rectal temperature < 38.4 C and, within 24 hours, 6 of the 7 ponies had rectal temperature < 38.3C. In contrast, all control ponies had rectal temperature > 39.2 C at 24 hours (P < 0.05). Of the 7 treated ponies, 4 no longer had signs of mental depression after the second day of treatment, and only 1 of the 7 ponies had mild signs of depression after the third day of treatment. In contrast, control ponies had high mental depression score during the observation period (P < 0.05). Feed intake improved in ponies of the treatment group, with feed intake of 4 of the 7 ponies returning to normal; the other 3 ponies were only mildly anorectic by the second day of treatment. Control ponies progressively decreased their feed intake during the observation period (P < 0.05). One control pony and 2 treated ponies developed diarrhea before the treatment/observation period began. Only 1 treated pony developed diarrhea after treatment began. Of the 8 control ponies, 7 developed diarrhea. Profound decrease in borborygmal sounds with silent periods lasting longer than 3 minutes was observed in 7 of the 8 control ponies. Only 1 of the 7 treated ponies had such profound decrease in borborygmi (P < 0.05). The decrease in borborygmal sounds progressed in the control ponies during the observation period. None of the treated ponies continued to have decreased borborygmi after treatment day 2 (P < 0.05). Of the 8 control ponies, 2 were euthanatized; all treated ponies survived. In survivors, signs lasted 8 to 17 (mean, 10) days in control ponies but only 1 to 5 (mean, 2.9) days in treated ponies.
Differences in virulence between two noncytopathic bovine viral diarrhea viruses in calves
Authors: Bolin Steven R. , Ridpath Julia F.
Published: January 2024

A noncytopathic bovine viral diarrhea virus (bvdv), bvdv-890, isolated from a yearling heifer that died with extensive internal hemorrhages, was compared for virulence in calves with noncytopathic bvdv-TGAN, isolated from an apparently healthy persistently infected calf. After challenge exposure with bvdv-890, nonimmune calves (n = 7) developed fever > 40 C, diarrhea, leukopenia, lymphopenia, neutropenia, and thrombocytopenia. Most calves (n = 6) died or were euthanatized by 19 days after challenge exposure. Challenge exposure with bvdv-890 did not induce disease in 2 calves that had congenital persistent infection with bvdv or in 3 calves that had neutralizing antibody titer > 4 against bvdv-890. After challenge exposure with bvdv-TGAN, nonimmune calves (n = 7) developed fever > 40 C and, rarely, diarrhea or lymphopenia. All of those calves survived challenge exposure. The average maximal titer of bvdv-890 isolated from serum was 1,000 times that of bvdv-TGAN. In calves infected with bvdv-890, the average maximal percentages of lymphocytes and platelets associated with virus were greater than those found in calves infected with bvdv-TGAN. Additional findings of epidemiologic significance were prolonged shedding of virus and delayed production of viral-neutralizing antibody in 1 calf challenge-exposed with bvdv-890. Also, after production of neutralizing antibody, mutant virus that was refractory to neutralization was isolated from calves challenge-exposed with bvdv-TGAN.
Pharmacokinetics of intravenously and orally administered pyrimethamine in horses
Authors: Clarke Cyril R. , Burrows George E. , MacAllister Charles G. , Spillers Diane K. , Ewing Patty , Lauer Andreas K.
Published: January 2024

Single-dose pharmacokinetic variables of pyrimethamine were studied in horses. Pyrimethamine (1 mg/kg of body weight) was administered iv and orally to 6 adult horses, and plasma samples were obtained at frequent intervals thereafter. Plasma pyrimethamine concentration was assayed by gas chromatography, and concentration-time data were analyzed, using a pharmacokinetic computer program. The iv and oral administration data were best described by 3-compartment and 1-compartment models, respectively. The median volume of distribution at steady state after iv administration was 1,521 ml/kg and the median elimination half-time was 12.06 hours. Mean plasma concentration after oral administration fluctuated between a maximal concentration of 0.18 µg/ml and 0.09 µg/ml (24 hours after dosing). Bioavailability after oral administration was 56%.
Pharmacokinetics, penetration into cerebrospinal fluid, and hematologic effects after multiple oral administrations of pyrimethamine to horses
Authors: Clarke Cyril R. , MacAllister Charles G. , Burrows George E. , Ewing Patty , Spillers Diane K. , Burrows S. Leon
Published: January 2024

Pharmacokinetics, csf penetration, and hematologic effects of oral administration of pyrimethamine were studied after multiple dosing. Pyrimethamine (1 mg/kg of body weight) was administered orally once a day for 10 days to 5 adult horses, and blood samples were collected frequently after the first, fifth, and tenth doses. The csf samples were obtained by cisternal puncture 4 to 6 hours after administration of the first, third, seventh, and tenth doses. Pyrimethamine concentration in plasma and csf was quantified by gas chromatography, and plasma concentration-time data were analyzed, using a pharmacokinetic computer program. Repeated daily dosing resulted in accumulation of pyrimethamine in plasma, with steady state being achieved within 5 days, when the mean peak plasma concentration was more than twice that measured after the first dose. Pyrimethamine concentration in csf was 25 to 50% of corresponding plasma concentration and did not appear to accumulate with successive administration of doses. Blood samples collected during and after the dosing regimen were submitted for hematologic analysis; neutrophil numbers decreased slightly, but remained within normal range for adult horses.
Clinical efficacy of tirilazad mesylate for treatment of endotoxemia in neonatal calves
Authors: Rose Marcy L. , Semrad Susan D.
Published: January 2024

The clinical efficacy of the lazaroid, tirilazad mesylate, a new therapeutic agent for prophylaxis and treatment of endotoxemia, was evaluated in 24 neonatal Holstein calves. Endotoxemia was induced by iv infusion of commercial Escherichia coli lipopolysaccharide (3.25 µg/kg of body weight) over 3 hours. Group-1 calves were given endotoxin alone; group-2 calves were given an infusion of 0.9% sterile saline solution, then were treated with tirilazad mesylate (1.5 mg/kg) 1 hour after the infusion was started. Group-3 calves were treated with tirilazad mesylate 1 hour after the start of the endotoxin infusion, and group-4 calves were given tirilazad mesylate 1 hour before the start of the endotoxin infusion.

Clinical signs of endotoxemia were mitigated by tirilazad mesylate. In addition, tirilazad mesylate protected calves from endotoxin-induced hyperglycemia; treatment after endotoxin infusion decreased the severity of hypoglycemia and prevented lactic acidosis. Treatment with tirilazad mesylate after initiation of endotoxin infusion was as protective as was pretreatment.
Effects of endotoxin-induced mastitis on the pharmacokinetic properties of aditoprim in dairy cows
Authors: Lohuis J. A. C. M. , Sutter H.-M. , Graser T. , Ludwig B. , van Miert A. S. J. P. A. M. , Rehm W. F. , Rohde E. , Schneider B. , Wanner M. , van Werven T.
Published: January 2024

Plasma disposition of aditoprim, a new dihydrofolate reductase inhibitor, was studied in healthy cows and cows with endotoxin-induced mastitis. A single dose of 5 mg of aditoprim/kg of body weight was administered iv to 5 healthy cows and to the same cows 3 weeks later at 2 hours after intramammary infusion of 0.1 mg of endotoxin into the rear quarters.

Mastitis developed in all endotoxin-infused quarters and cows had systemic signs of disease (fever, tachycardia, depression) from 2 to 10 hours after infusion of endotoxin.

Pharmacokinetic characteristics of aditoprim in healthy cows were a large volume of distribution (6.28 L/kg), a systemic clearance of 0.82 L/h/kg, and an elimination halflife of 7.26 hours. In cows with mastitis, plasma concentrations of aditoprim were lower between 5 and 26 hours after injection. The systemic clearance (1.00 L/h/kg) and the volume of distribution (12.25 L/kg) were significantly higher in cows with mastitis, but elimination half-life was not significantly different.

The lower plasma concentrations of aditoprim between 5 and 26 hours after injection in cows with mastitis are explained by fluid compartment shifts and/or blood flow changes induced by mastitis, although increased elimination of aditoprim in cows with mastitis cannot completely be ruled out.

The antibacterial activity of aditoprim is nearly the same as that of trimethoprim. The longer elimination half-life time of aditoprim, however, indicates that it may have a practical pharmacotherapeutic advantage over trimethoprim.
Pharmacokinetic evaluation of enrofloxacin administered orally to healthy dogs
Authors: Walker Robert D. , Stein Gary E. , Hauptman Joseph G. , MacDonald Kathleen H.
Published: January 2024

Enrofloxacin was administered orally to 6 healthy dogs at dosages of approximately 2.75, 5.5, and 11 mg/kg of body weight, every 12 hours for 4 days, with a 4-week interval between dosage regimens. Serum and tissue cage fluid (tcf) concentrations of enrofloxacin were measured after the first and seventh treatments. The mean peak serum concentration occurred between 1 and 2.5 hours after dosing. Peak serum concentrations increased with increases in dosage. For each dosage regimen, there was an accumulation of enrofloxacin between the first and seventh treatment, as demonstrated by a significant (P = 0.001) increase in peak serum concentrations. The serum elimination half-life increased from 3.39 hours for the 2.75 mg/kg dosage to 4.94 hours for the 11 mg/kg dosage. Enrofloxacin accumulated slowly into tcf, with peak concentrations being approximately 58% of those of serum. The time of peak tcf concentrations occurred between 3.8 hours and 5.9 hours after drug administration, depending on the dosage and whether it was after single or multiple administrations. Compared with serum concentrations (area under the curvetcf/area under the curveserum), the percentage of enrofloxacin penetration into tcf was 85% at a dosage of 2.75 mg/kg, 83% at a dosage of 5.5 mg/kg, and 88% at a dosage of 11 mg/kg. All 3 dosage regimens of enrofloxacin induced continuous serum and tcf concentrations greater than the minimal concentration required to inhibit 90% (mic90) of the aerobic and facultative anaerobic clinical isolates tested, except Pseudomonas aeruginosa. Only the 11 mg/kg dosage regimen provided continuous serum and tcf concentrations that exceeded the mic90 for P aeruginosa isolates; whereas none of the dosages induced serum or tcf concentrations greater than the mic90 of the obligate anaerobic bacteria tested.
Quantitative analysis of computer-averaged electromyographic profiles of intrinsic limb muscles in ponies at the walk
Authors: Jansen Margot O. , van Raaij J. A. G. M. , van den Bogert A. J. , Schamhardt H. C. , Hartman W.
Published: January 2024

The function of several intrinsic muscles of the fore- and hind limbs of 5 ponies walking normally was evaluated via surface electromyography. Electromyographic signals were band-pass filtered, rectified, linear enveloped, and standardized to the stride duration. Mean data from the muscles of the left and right limbs that were obtained from at least 30 strides in 2 recording sessions were recorded as electromyographic signals-time curves. The timing of muscle activity was determined from these graphs. On the basis of the major peaks in the electromyographic signal, muscle functions were identified.

In the forelimb, the extensor carpi radialis muscle was involved in extension of the carpus at the end of the swing phase of the stride, and it provided support to flexion of the cubital joint at the beginning of the swing phase. The common digital extensor muscle extended the distal joints of the forelimb at the end of the swing phase. The ulnaris lateralis muscle provided support to extension of the cubital joint at the beginning of the stance phase, and the flexor carpi radialis muscle flexed the carpus at the beginning of the swing phase. The flexor carpi ulnaris muscle extended the cubital joint at the end of the swing phase.

In the hind limb, the long digital extensor muscle flexed the tarsus at the beginning of the swing phase and extended the digital joints preceding the stance phase. The deep digital flexor muscle prevented overextension of the distal interphalangeal joint during the stance phase and flexion of the digital joints during the swing phase. The gastrocnemius muscle prevented flexion of the tarsus on impact and supported flexion of the femorotibial joint at the beginning of the swing phase.
Cohort study of natural transmission and two methods for control of caprine arthritis-encephalitis virus infection in goats on a California dairy
Authors: Rowe J. D. , East N. E. , Thurmond M. C. , Franti C. E. , Pedersen N. C.
Published: January 2024

A prospective observational cohort study of 361 dairy goat kids was conducted to compare 2 methods of controlling caprine arthritis-encephalitis virus infection under commercial dairy conditions. To compare effectiveness of feeding kids pasteurized milk vs serologic testing and segregation in addition to pasteurized milk feeding, goats were monitored up to the age of 30 months by use of monthly agar gel immunodiffusion testing. Survival analysis methods were used to determine whether age at seroconversion differed between the 2 groups. Significantly lower rates of seroconversion were observed in the segregated group (P < 0,001), compared with the nonsegregated group. Of 193 goats in the pasteurized milk-only group, 146 (75.6%) seroconverted within the 30-month study period, whereas infection was detected in 39 (23.2%) of 168 goats in the test/segregated group. Nonsegregated goats were 3.37 times more likely to seroconvert by 24 months of age, and 70.3% of seroconversions by 24 months of age could be attributed to nonsegregation. For age-specific intervals beyond 180 days of age, 70 to 100% of seroconversions could be attributed to lack of segregation. Cohort life tables for age at seroconversion were reported for each group. Type of colostrum fed, sex, and weaning group (season) were not significantly associated with age at seroconversion. Saanen goats had lower age-specific risk of seroconversion in the nonsegregated group alone and overall. Non-Saanen goats were 1,5 times more likely to seroconvert than were Saanen goats, when adjusted for a possible confounding effect of weaning group. Results indicate that pasteurized milk feeding and routine test and segregation would be a substantially more effective means of control of the disease in dairy goat herds than would pasteurized milk feeding alone.
Patterns of expression of feline cytokeratins in healthy epithelia and mammary carcinoma cells
Authors: Ivanyi D. , Minke J. M. H. M. , Hageman PhF. C. , Groeneveld E. , van Doornewaard G.
Published: January 2024

Expression of keratins (cytokeratins, ck) in healthy feline epithelia and 2 established feline mammary carcinoma cell lines was examined immunohistochemically and by use of immunoblotting analysis. A panel of specific anti-CK monoclonal antibodies (MAb) identifying epitopes unique to individual keratins or shared by 2 (or 3) ck polypeptides was used. Besides already available antihuman ck MAb, this panel of MAb consisted of 9 newly generated anti-human ck MAb and 1 newly generated anti-feline ck MAb.

Immunohistochemical analysis on normal epithelia revealed that most of the anti-human ck MAb and the antifeline ck MAb reacted with both feline and human epithelia, with a comparable tissue distribution pattern. However, slight differences in ck tissue distribution pattern between human beings and cats were detected by one MAb. Immunoblotting analysis revealed that all antihuman ck MAb that were immunohistochemically reactive with feline tissues detected analogous ck in cats, indicating the presence of a number of common epitopes on human and feline ck.

Two continuous cell lines derived from 2 distinct feline mammary adenocarcinomas, K248C and K266, were analyzed with respect to their ck phenotype. Although no difference in ck expression between the 2 cell lines was detected in vitro, a difference in ck phenotype was detected on subcutaneous transplantation of the 2 cell lines into nude mice. Although the K248C-induced adenocarcinomas maintained the same ck phenotype as observed in vitro, the ck pattern of the K266 heterotransplants, growing as adenosquamous carcinomas, changed with squamous differentiation.

Our findings confirm the high degree of homology between mammalian ck, and on the basis of those findings, we suggest that ck proteins provide a set of markers valuable for the characterization of normal and neoplastic feline tissues and for studies of squamous metaplasia.
Comparison of two catheter withdrawal speeds during simultaneous urethral pressure profilometry in anesthetized bitches
Authors: Gregory Susan P. , Holt Peter E. , Parkinson Timothy J.
Published: January 2024

Maximal urethral closure pressure, functional profile length, and number of respiratory peaks on the resting urethral pressure profile, expressed as a percentage of those occurring on the bladder pressure recording, were compared at catheter withdrawal speeds of 1 and 3 mm/s in 30 anesthetized bitches.

Significant (P < 0.001) differences were found in maximal urethral closure pressure and percentage of transmission of respiratory peaks between the 2 speeds. Significant difference was not detected in functional profile length.
Interaction of bovine chorioallantoic membrane explants with three strains of Brucella abortus
Authors: Samartino Luis E. , Enright Frederick M.
Published: January 2024

Chorioallantoic membrane (cam) explants were used to determine the in vitro growth and cytotoxic potential of 3 strains of Brucella abortus. Bovine cam explants were inoculated with 2 × 107 colony-forming units of the pathogenic strain 2308, attenuated strain 19, or the rough strain RB51 of B abortus. After inoculation, the explants were harvested and examined at 2 or 4 hours, 12 or 14 hours, and 24 or 26 hours of incubation. Bacterial growth associated with each explant was determined by counting colony-forming units. The degree of cellular damage in each explant associated either with bacterial growth or bacterial toxins was evaluated by morphometric analysis after trypan blue staining.

Significant differences were not detected in the numbers of bacteria of any strain of B abortus in the cam explants at comparable time intervals. The rate of growth of the bacteria in cam explants was higher between 2 and 12 hours after inoculation than between 12 and 24 hours after inoculation. Cytotoxic effects associated with strain 2308 were significantly (P < 0.05) greater than that caused by other strains. Cytotoxic effects associated with strain 19 and rough strain RB51 were similar, and both were significantly (P < 0.05) greater than the phosphate buffer solution control. Chorioallantoic membrane explants inoculated with a filtrate of heat-killed strain 2308 induced minimal cellular damage, compared with that caused by the viable bacteria. These results indicated that the number of B abortus in trophoblasts was independent of the degree of cellular damage.
Taurine depletion and cardiovascular disease in adult cats fed a potassium-depleted acidified diet
Authors: Dow Steven W. , Fettman Martin J. , Smith Katharine R. , Ching Shelly V. , Hamar Dwayne W. , Rogers Quinton R.
Published: January 2024

Although low plasma taurine concentrations have been associated with congestive cardiomyopathy in cats, the cause of taurine depletion in cats consuming adequate quantities of taurine is unknown. Taurine depletion and cardiovascular disease (cardiomyopathy and thromboembolism) developed unexpectedly in 3 of 6 healthy adult cats during a potassium-depletion study. Plasma taurine concentration decreased significantly (P < 0.05) and rapidly over an 8-week period (from 98 to 36 nmol/ml) in 6 cats that consumed a potassium-deficient diet (0.20% potassium, dry matter basis) that was acidified with 0.8% ammonium chloride, despite containing dietary taurine concentrations (0.12% dry matter basis) in excess of amounts currently recommended. Taurine concentrations were significantly lower in cats fed the acidified diet than in 6 cats fed a potassium-deficient diet that was not acidified (36 nmol/ml vs 75 nmol/ml) after 8 weeks. In addition, plasma taurine concentrations did not decrease over a 6-month period in 8 cats that were fed a potassium-replete diet with acidifier. Plasma taurine concentrations were lowest in 3 cats that died of cardiovascular disease in the group receiving potassium-deficient, acidified diets. These data indicated an association between taurine and potassium balance in cats and suggested that development of taurine depletion and cardiovascular disease may be linked to concurrent potassium depletion.
Effects of analog filtering on brain stem auditory-evoked potentials in dogs
Authors: Kawasaki Yasuaki , Inada Shichiro
Published: January 2024

Effects of analog filter frequency on brain stem auditory-evoked potentials (baep) were investigated in 7 nonsedated dogs. The baep were recorded successively at various low-pass (lp) and high-pass (hp) filter frequency settings. The analog filters had a rolloff of 6 dB/octave.

Decrease of LP filter frequency from 30 kHz to 100 Hz caused prolongation of the peak latency and reduction of the peak-to-peak (from a positive peak to the following trough) and absolute (from a positive peak to the baseline) amplitudes for all peaks, except the peak latency for P5 and the absolute amplitude for P4. Changes in these variables were statistically significant (P < 0.05) at different cutoff frequencies specific for the individual peaks. The interpeak latency between P1 and P4, and P4/P1 peak-to-peak amplitude ratio were not changed significantly. At the lowest (lp filter frequency of 100 Hz, positive peaks (fast waves) seemed to be superimposed on a slow positive wave (slow wave). In contrast, increase of hp filter frequency from 0.53 to 160 Hz did not result in significant changes for any peaks, except for reduction in the absolute amplitude of P4. The various effects of lp filter frequency and negligible effects of hp filter frequency on individual peaks may be attributable to their frequency composition and/or elimination of the slow wave at higher hp filter frequency settings.

On the basis of our results, lp filter setting of 3 kHz and HP filter setting of ≤ 53 Hz are recommended for recording of baep in dogs. These settings sufficiently attenuate unwanted high-frequency artifacts, are adequate for recording of fast and slow waves, and have only slight effects on configurations, peak latencies, and amplitudes.
Humoral immune response to feline immunodeficiency virus in cats with experimentally induced and naturally acquired infections
Authors: Egberink H. F. , Keldermans C. E. J. M. , Koolen M. J. M. , Horzinek M. C.
Published: January 2024

Sera from cats with naturally acquired and experimentally induced feline immunodeficiency virus (fiv) infections were tested by immunoblot analysis, radioimmunoprecipitation assay (ripa), and a complex trapping/ blocking elisa. In sequentially obtained samples from experimentally inoculated cats, antibodies against the envelope protein gp120 and the core protein pl5 were the first to appear, as indicated by results of ripa, using lysates of fiv-infected lymphocytes. Antibodies could be detected as early as 2 weeks after infection, followed by a response against p24, p43, and p50. By immunoblot analysis, p24 and p15 were the first proteins detectable between postinoculation weeks 3 and 5; an anti-envelope response was never found by use of this assay, but was found by ripa. Using the latter test, most sera of naturally infected cats were found to recognize the major core protein p24 in addition to 1 or more minor core proteins. All 40 sera tested precipitated the envelope protein; 3 reacted exclusively with it. A complex trapping/blocking elisa was developed to quantitate the anti-p24 response. Sera from healthy Fiv-infected cats were shown to have higher anti-p24 titer than did those from diseased cats.
Effects of equine infectious anemia virus on hematopoietic progenitors in vitro
Authors: Swardson Christine J. , Kociba Gary J. , Perryman Lance E.
Published: January 2024

Direct effects of equine infectious anemia virus (eiav) on hematopoiesis in vitro were studied. Bone marrow mononuclear cells from clinically normal horses were incubated with 100 TCID50 of ELAV/107 cells. These cells were cultured to assay for colonies derived from erythroid pro-genitors, granulocyte/monocyte progenitors, and fibroblastic progenitors. The eiav had a selective suppressive effect on the erythroid progenitors. Colony-forming units-erythroid were suppressed to 80% of that for medium controls (P = 0.011). Burst-forming units-erythroid were suppressed to 70% of that for medium controls (P = 0.003). Significant effect was not apparent on colony-forming units-granulocyte/macrophage or on colony-forming units-fibroblastic.
Serum γ-glutamyltransferase activity and protein concentration at birth and after suckling in calves with adequate and inadequate passive transfer of immunoglobulin G
Authors: Perino L. J. , Sutherland R. L. , Woollen N. E.
Published: January 2024

In an effort to characterize the activity of serum γ-glutamyltransferase (ggt) in newborn calves before and after suckling and to explore the usefulness of serum ggt as an indicator of failure of passive transfer in calves, blood samples were collected from the first calves of 48 cows at the time of birth and at 1 day of age. Serum was harvested, and concentrations of IgG and protein and activity of ggt were determined. Morbidity and mortality events were monitored from birth to weaning. Calves suckling colostrum had 10 and 1.3 times greater serum concentrations of IgG and protein, respectively, and a 26 times greater serum activity of ggt, compared with concentrations at birth. Increases in ggt activity and protein concentration were correlated to increases in IgG concentration. Calves classified as having failure of passive transfer (< 800 mg of IgG/dl) had a 9.5 times greater risk of becoming sick prior to weaning, compared with calves determined to have partial failure of passive transfer and clinically normal calves (P= 0.0004). The sensitivity and specificity of a cutoff value of 200 IU of ggt/L of serum for diagnosing failure of passive transfer were 80 and 97%, respectively. The sensitivity and specificity of a cutoff value of 4.2 g of protein/dl of serum for diagnosing failure of passive transfer were 80 and 100%, respectively. The Kappa values for diagnosis of failure of passive transfer, using serum concentrations of IgG vs activity of ggt, IgG vs protein, and ggt vs protein, were 0.72, 0.86, and 0.79, respectively. The value of using ggt activities for diagnosis of hepatic lesions is limited during at least the first week of life in calves that consume adequate amounts of colostrum. The most cost-effective and rapid indicator of passive immune status in this study was determination of serum total protein. Serum activity of ggt also gave reliable indications of passive immune status. Procedures used to determine these values were less expensive and gave results sooner than single radial immunodiffusion for IgG.
Comparison of stressed simultaneous urethral pressure profiles between anesthetized continent and incontinent bitches with urethral sphincter mechanism incompetence
Authors: Gregory Susan P. , Holt Peter E.
Published: January 2024

The popular urodynamic technique of stressed urethral pressure profilometry used for investigation of genuine stress incontinence in women was adapted and applied to bitches. The aim was to assess the suitability and reproducibility of the technique in the canine species, and to determine whether differences seen in continent and incontinent women were found in bitches.

Resting and stressed simultaneous urethral pressure profiles were obtained for 25 continent and 25 incontinent bitches, the latter diagnosed as having urethral sphincter mechanism incompetence. The stressed urethral pressure profiles were produced by ballottement of the abdomen during catheter withdrawal. The degree of stress induced was consistent and had got short-term reproducibility.

Highly significant (P < 0.001) differences in the percentage of negative spikes extending below the resting intravesical pressure were found between continent and incontinent bitches. Significant differences were not observed in the pressure transmission profiles between continent and incontinent bitches; both groups had a gradual decrease in pressure transmission from the bladder neck to the external urethral orifice.

The distance from the start of the urethral pressure profile to the first negative peak (attributable to respiration or ballottement) on the subtracted profile was compared with the radiographic distance that the bladder neck was positioned with respect to the cranial pubic brim, taking body weight and continence status into account. Body weight and continence status did not have significant effect on the relation in either instance. The distance between the start of the urethral pressure profile and the first negative peak induced by respiration was significantly (P < 0.05) related to the bladder neck position with respect to the cranial pubic brim, although it accounted for little of the total variance. Relation between the same variables during stressed urethral pressure profilometry, induced by abdominal ballottement, was not significant.
Recognition of triiodothyronine-containing epitopes in canine thyreoglobulin by circulating thyroglobulin autoantibodies
Authors: Gaschen F. , Thompson J. , Beale K. , Keisling K.
Published: January 2024

Serum triiodothyronine autoantibody (T3 AA), triiodothyronine (T3), and thyroxine (T4) concentrations were determined in 45 canine sera containing substantial amounts of thyroglobulin autoantibodies (Tg AA); sera also were assayed to investigate the ability of free T3 to inhibit Tg AA binding to canine Tg, Serum T3 AA concentrations defined 2 groups of sera; 28 sera had low T3 AA concentration (≤ 20 ng/ ml) and 17 sera had high T3 aa concentration (≥ 250 ng/ml).

Direct linear correlation between T3 AA concentration and apparent serum T3 concentration was observed (r = 0.75). Serum with low T3 AA concentration had apparent T3 concentration that was significantly (P < 0.01) lower than that in serum with high T3 AA concentration. Mean serum T4 concentration was not significantly different between serum with low or high T3 AA concentration. Mean Tg AA activity was significantly (P < 0.05) lower in serum with low T3 AA concentration than in serum with high T3 AA concentration. Addition of free T3 to serum significantly (P < 0.05) decreased detectable activity of Tg AA in both groups of sera. However, significant difference in magnitude of the reduction was not observed between sera with low or high T3 AA concentration.

Results indicate that a fraction of Tg AA recognizes T3-containing epitopes in Tg. Increased prevalence of T3 AA for serum with high Tg AA activity indicates that T3 AA may be another valid indicator of lymphocytic thyroiditis. These antibodies may be generated against the hormonogenic epitopes of Tg.
Effect of topically applied demecarium bromide and echothiophate iodide on intraocular pressure and pupil size in Beagles with normotensive eyes and Beagles with inherited glaucoma
Authors: Gum Glenwood G. , Gelatt Kirk N. , Gelatt Justina K. , Jones Robin
Published: January 2024

Topically applied demecarium bromide (0.125 and 0.25%) and echothiophate iodide (0.125 and 0.25%) solutions were evaluated in Beagles with nor-motensive eyes and Beagles with inherited glaucoma. In single-dose studies, the effects of intraocular pressure (IOP) and pupil size (PS) were measured in eyes before drug treatment and in drug- and nondrug-treated eyes. Both concentrations of the 2 drugs induced long-term miosis and decrease in IOP in nor-motensive eyes of Beagles and of eyes of Beagles with inherited glaucoma. Demecarium bromide (0.125 and 0.5%) decreased IOP for 49 and 55 hours, respectively. Echothiophate iodide (0.125 and 0.5%) reduced IOP for 25 and 53 hours, respectively. The miosis associated with both concentrations of the 2 drugs generally paralleled the decreases in IOP.
Reduction of isoflurane anesthetic requirement by medetomidine and its restoration by atipamezole in dogs
Authors: Ewing Karin Kuersten , Mohammed Hussni O. , Scarlett Janet M. , Short Charles E.
Published: January 2024

The isoflurane-sparing effect of the α2-adrenergic agonist medetomidine (30 μg/kg of body weight, IV) was tested in 7 dogs, using a blinded, randomized-block study design. The baseline minimal alveolar concentration (mac) of isoflurane was 1.18 vol% (95% confidence interval [097,1.39])- Medetomidine significantly (P < 0.003) reduced isoflurane mac by 47.2%. Atipamezolc (0.3 mg/kg, iv), an α2-adrenergic antagonist, completely reversed the effect of mcdetomidine on isoflurane mac. Atipamezole alone did not significantly alter isoflurane mac.

After medetomidine administration, marked bradycardia developed in all dogs and persisted for more than 2 hours Mean arterial blood pressure increased acutely, but later decreased, and hypotension persisted for more than 2 hours. Atipamezole reversed the bradycardic and hypotensive effects of medetomidine.

Results of this study indicate that medetomidine mav be useful in clinical cases in which isoflurane mac-reduction is desirable and that atipamezole might be used to reverse desirable and undesirable effects of medetomidine during isoflurane anesthesia.
Detection of Akabane viral antigen and immunoglobulin-containing cells in ovine fetuses by use of immunoperoxidase staining
Authors: Narita Minoru , Kawashima Kenji
Published: January 2024

Akabane virus (akv) strain OBE-1 was inoculated IV into 17 pregnant sheep. Ten fetuses infected at 29 to 45 days of gestation and examined 29 to 30 days later had AKV antigen in the following groups of cells: neuroglial cells in the brain and spinal cord, ganglion cells in the cranial and abdominal ganglia, layer of ganglion cells in the retina, ganglion cells (Auerbach's plexus) in small intestine, hepatocytes, cells in the arterial wall of mesenteric membrane, and trophoblast cells in the placenta. Prior to detection of circulating virus-neutralizing antibody, immunoglobulin-containing cells were found initially at 59 days of gestation in the peripheral portion of white pulp tissue in the spleen. After that, numbers of immunoglobulin-containing cells gradually increased. These results indicated that akv may have strong affinity for neuronal and ganglional cells in infected fetuses and immunoglobulin-containing cells might be considered the earliest immunologic response to AKV replication in the fetus.
Ultrasonographic observations of the flexor tendons and ligaments of the metacarpal region of horses
Authors: Nicoll R. G. , Wood A. K. W. , Martin I. C. A.
Published: January 2024

Observations were made in dorsal and sagittal planes of the ultrasonographic mean gray scale of the flexor tendons and ligaments of the metacarpal regions of 5 Thoroughbred geldings, during weight bearing and nonweight bearing. In images made when the horses were nonweight bearing, the mean gray scale of the superficial and deep digital flexor tendons and accessory ligament was significantly reduced, but that of the interosseous medius muscle (suspensory ligament) was not. When relaxed, collagen fiber bundles in the tendons and ligaments acted as diffuse, rather than specular, reflectors of ultrasonic waves leading to localized regions of hypoechogenicity and a consequent reduction in mean gray scale. The suspensory ligament, however, remained under tension during nonweight bearing and so mean gray scale was not reduced. Analyses of the ultrasonographic mean gray scale have the potential to provide quantitative data relating to the changes in echogenicity that develop in injured equine tendons and ligaments.
Isolation and characterization of encephalitic bovine herpesvirus type 1 isolates from cattle in North America
Authors: d’Offay Jean M. , Mock Richard E. , Fulton Robert W.
Published: January 2024

Nine cns bovine herpesvirus type 1 (bhv-1) isolates, recovered from bovine brain samples submitted to the Texas Veterinary Medical Diagnostic Laboratories from 1974-1989, were compared by analyzing their dna restriction endonuclease (re) fragment migration pattern. Seven had pattern similar to that of the respiratory bhv-1 Cooper strain. The remaining 2 isolates, however, had variant patterns, similar to that of each other, but completely different from patterns for the other 7. The re patterns of these 2 variants were similar to published re patterns for 2 encephalitic or neuropathogenic bhv-1 strains — the Australian N-569 strain and the Argentine A-663 strain. One of the Texas encephalitic variants (No. 30326) was isolated from the cns of a calf that died during an epizootic of encephalitis in 1974. The other, designated TX-89, was isolated in 1989 from the cns of a 7-month-old feedlot steer with acute fatal encephalitis. Microscopic lesions of encephalitis with neuronal degeneration and intranuclear inclusions were observed for 3 of the 9 isolates, the 2 variant isolates (No. 30326 and TX-89), and a respiratory isolate. The remaining 6 cns isolates, all respiratory subtypes, were recovered from cattle that did not have clinical cns disease or gross or microscopic cns lesions; in 5 of these cattle, virus was recovered from at least 1 other organ (lungs) besides the cns. We conclude that the cns of calves can be naturally infected with 2 distinct bhv-1 subtypes, the respiratory and the encephalitic, and that the encephalitic subtype (subtype 3 or bhv-1.3) has been present in Texas cattle since at least 1974.
Direct isolation and identification of recombinant pseudorabies virus strains from tissues of experimentally co-infected swine
Authors: Dangler Charles A. , Henderson Louise M. , Bowman Larissa A. , Deaver Robin E.
Published: January 2024

Tissue homogenates were obtained from swine co-infected with 2 vaccine strains of pseudorabies virus (prv). Viral isolates derived by serial plaque purification directly from tissue homogenates, without an intervening step of isolation and amplification on cell cultures, were characterized as recombinant and parental prv genotypes on the basis of thymidine kinase and glycoprotein X gene combinations. Use of limiting dilutions and recovery of virus isolates as individual plaques minimized the likelihood of in vitro recombination serving as a confounding source of recombinant prv. The thymidine kinase and glycoprotein X gene sequences were classified as wild-type or deleted, using a battery of polymerase chain reaction assays. Results substantiate the observation that prv vaccine strains can form genetic recombinants in vivo after experimentally induced co-infection.
Pharmacokinetics of cefotaxime in neonatal pony foals
Authors: Gardner Sarah Y. , Sweeney Raymond W. , Divers Thomas J.
Published: January 2024

Serum concentrations of cefotaxime and desacetylcefotaxime were measured in 1-week-old pony foals after iv administration of a single dose of cefotaxime.

The cefotaxime disposition data conformed to a two-compartment model with elimination half-life of 0.60 hour. The combined cefotaxime and desacetylcefotaxime data was best described by a four-compartment model. The apparent half-life describing the disappearance of desacetylcefotaxime was 1.69 hours.

Dosage of 40 mg/kg of body weight given iv every 4 to 6 hours for neonatal foals with gram-negative septicemia and every 2 hours for foals with meningitis is recommended for further study.