bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of the somatostatin analogue octreotide on gastric fluid pH in ponies
Authors: Sojka J. E. , Weiss J. S. , Samuels M. L. , You Guey-Mei 
Published: January 2024

SUMMARY
The effect of the somatostatin analogue, octreotide, on gastric fluid pH was investigated in 4 ponies. Gastric fluid pH was determined after sc administration of octreotide or physiologic saline solution (control). A baseline sample of fluid was obtained, the agent was given, and 8 additional samples were collected hourly. Administration of octreotide at all dosages tested (0.1, 0.5, 1.0, and 5.0 μg/kg of body weight) increased gastric pH to > 5.0. Baseline values were consistently < 2.7. Administration of octreotide at these same dosages induced gastric pH values > 4.0 for 2.4 ± 1.2, 4.8 ± 0.8, 5.7 ± 1.3, and 5.4 ± 2.6 (mean ± sd) continuous hours, respectively. Treatment at all dosages increased the pH of gastric fluid, compared with control values. The duration of the increase in pH was significantly (P < 0.05) different than that of the control treatment, even for the lowest dosage, 0.1 μg/kg.
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

SUMMARY
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

SUMMARY
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

Summary
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

Summary
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

Summary
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

Summary
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

Summary
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

Summary
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

Summary
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

Summary
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

Summary
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

Summary
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.