bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resistance to gentamicin and amikacin of gram-negative organisms isolated from horses
Authors: Orsini James A. , Benson Charles E. , Spencer Pamela A. , Van Miller E. 
Published: February 2025

SUMMARY
Resistance of gram-negative bacteria to gentamicin has become an increasingly common problem among clinical isolates from human beings. Susceptibility of isolates from horses to gentamicin and amikacin was evaluated for the period from July, 1983 to June, 1985. All isolates of Escherichia coli, and species of Enterobacter, Klebsiella, Proteus, and Pseudomonas examined were susceptible to amikacin, except 2 of the 46 Pseudomonas isolates. In contrast, 13 to 50% of isolates were resistant to gentamicin. Escherichia coli, and Klebsiella, Proteus, and Enterobacter species isolates were highly significantly more susceptible to amikacin (P < 0.01) than to gentamicin. Pseudomonas spp (P = 0.13) were not significantly different in susceptibility to the 2 drugs. There was significant variation among genera in their susceptibility to gentamicin (P = 0.002), primarily because of the frequency of resistance in isolates of Klebsiella spp and Proteus spp, compared with the other 3 organisms (E coli, Enterobacter spp, and Pseudomonas spp). There was no significant difference of susceptibility to amikacin among the genera studied (P = 0.06).
Critical and controlled tests of activity of a macrocyclic lactone (compound F28249-α) against natural infections of internal parasites of equids
Authors: Lyons E. T. , Drudge J. H. , Tolliver S. C. 
Published: February 2025

SUMMARY
Thirteen critical tests (n = 11 horses and 2 ponies) and 4 controlled tests (n = 4 donkeys and 6 horses) were performed to evaluate the activity of the experimental macrocyclic lactone compound F28249-α against internal parasites of equids. In the critical tests, activity was determined mainly against the large parasites, but 1 critical test also included benzimidazole-resistant small strongyles. In the controlled tests, evaluation of drug activity included large parasites and stomach worms in all 4 tests, and lungworms in 2 tests. The period between treatment and euthanasia was 6 to 9 days for the critical tests and 14, 17, or 52 days for the controlled tests. The compound was administered by stomach tube at dose rates of 1, 2, 3, 3.5, or 4 mg/kg of body weight.
In the critical tests, removal at all 5 dose rates was 100% for Gasterophilus nasalis (2nd and 3rd instars), Parascaris equorum (mature), Strongylus vulgaris, and Strongulus edentatus from the gastrointestinal tract. For Gasterophilus intestinalis in the stomach, mean removals of 2nd instars were 88% at the rate of 2 mg/kg and 93% to 100% at rates ≥ 3 mg/kg. For 3rd instars, mean removals were 7% at 1 mg/kg, 77% at 2 mg/kg, 90% at 3 mg/kg, and 98% at 3.5 mg/kg. Discharge of G intestinalis in feces was typically a slow, prolonged process and probably higher removal values, especially at lower dose rates, would have attended a longer interval after treatment before necropsy examination. There was 100% removal of population B, benzimidazole-resistant small strongyles in the single critical test.
Controlled tests at the 4 dose rates between 2 and 4 mg/kg resulted in variable activity against G intestinalis and Oxyuris equi, but efficacious removals were recorded for S vulgaris, S edentatus, Draschia megastoma, Habro-nema muscae, Trichostrongylus axei, and Dictyocaulus arnfieldi.
In critical and controlled tests, there was some indication of drug activity against parenteral stages of S edentatus and S vulgaris; activity was best in the control test equids euthanatized 52 days after treatment. There did not appear to be drug activity on eyeworms (Thelazia lacrymalis) or tapeworms (Anoplocephala spp).
Toxicosis of transient nature was observed in 1 horsei treated at 4 mg/kg.
DNA polymorphism analysis of hereditary multiple exostoses in horses
Authors: Li Joseph K. K. , Moloney Brian K. , Shupe James L. , Gardner Eldon J. , Leone Nicole C. , Elsner Yoko 
Published: February 2025

SUMMARY
Genomic dna polymorphisms obtained by restriction fragment-length polymorphism from healthy horses and horses with hereditary multiple exostoses were analyzed. These dna were digested by 12 restriction enzymes and were hybridized against 6 isotopically labeled oncogene probes. Hybridization was not detected with the viral oncogene, v-ras, which indicated this oncogene was absent in the equine genome. Oncogenes (c-raf-1, c-fes, c-myb, c-myc, and c-sis) were present and had similar hybridization patterns and signal intensities in dna from healthy horses and horses with hereditary multiple exostoses. Unique and distinct restriction fragment-length polymorphisms were detected with the c-raf-1 probe only in BamHI- and PstI-digested equine dna.
Trypsin treatment of bovine ova after in vitro exposure to vesicular stomatitis virus
Authors: Stringfellow D. A. , Lauerman L. H. , Thomson M. S. 
Published: February 2025

SUMMARY
Preimplantation bovine ova were exposed in vitro to vesicular stomatitis virus, Indiana serotype, to document adherence of the virus to the zona pellucida. To determine the efficacy of this treatment, some of the ova were treated with trypsin after exposure to the virus. Vesicular stomatitis virus was isolated from 5 of 10 groups of zona pellucida-intact ova after 12 sequential washes without trypsin treatment. Vesicular stomatitis virus was also isolated from 4 of 11 groups of zona pellucida-intact ova after trypsin treatment.
Distribution of persistent Salmonella typhimurium infection in internal organs of swine
Authors: Wood Richard L. , Pospischil Andreas , Rose Rebecca 
Published: February 2025

SUMMARY
Experiments were conducted to establish a persistent Salmonella typhimurium infection in convalescent swine, and to determine rate of shedding and distribution of the organism in internal organs. Naturally farrowed Salmonella-free pigs (n = 37) were orally exposed to S typhimurium when 7 to 8 weeks old. Fecal samples, tonsillar scrapings, and rectal swab specimens were examined bacteriologically for S typhimurium at weekly intervals after exposure until necropsy (maximum of 28 weeks after exposure). Necropsies of 1 to 4 randomly selected pigs were conducted at 2, 4, and 7 days and at 2, 4, 6, 8, 12, 16, 20, 24, and 28 weeks after exposure. The following internal organs were examined bacteriologically for S typhimurium: liver, spleen, kidney, gallbladder, heart, lung, and stomach; segments of the intestinal tract with corresponding lymph nodes; lymph nodes from lymphocenters of the head and neck, thoracic and abdominal cavities, pelvic wall, and thoracic and pelvic limbs. Fecal samples were 83 to 100% culture-positive up to postexposure (pe) week 22, then varied from 14 to 67% positive until pe week 28. At least 60% of tonsillar swab specimens and 50% of rectal swab specimens were culture-positive up to pe week 20, after which they varied from 0 to 70% positive until pe week 28. At necropsy, S typhimurium was recovered most frequently from tonsils (93.5% positive), followed by segments of the intestinal tract from caudal portion of jejunum to rectum (71% recovery from cecum), and mandibular (54.8%) and ileocolic (45.2%) lymph nodes. The organism generally did not persist beyond pe week 2 in other lymph nodes of the head and neck, lymph nodes of the abdominal wall, thoracic cavity, or limbs, or in heart, liver, or spleen. The gallbladder, kidney, and lungs of all pigs were culture-negative.
Differences in virulence between two strains of Streptococcus suis type II after experimentally induced infection of newborn germ-free pigs
Authors: Vecht U. , Arends J. P. , van der Molen E. J. , van Leengoed L. A. M. G. 
Published: February 2025

SUMMARY
Fifteen newborn germ-free pigs were inoculated with 2 strains, D-282 and T-15, of Streptococcus suis type II. Some pigs also were preinoculated with Bordetella bronchiseptica, which successfully predisposed them to S suis infection. The 2 streptococcal strains were differentiated by muramidase treatment, which released certain high molecular-weight proteins, termed muramidase-released proteins (mrp), from the cell wall of strain D-282, but not from the cell wall of strain T-15. Only strain D-282 (mrp-positive) induced clinical signs of disease and markedly increased neutrophil numbers in pigs. Streptococci were more frequently isolated from fecal swab specimens obtained from pigs inoculated with strain D-282 (mrp-positive) than from specimens obtained from pigs inoculated with strain T-15 (mrp-negative). Both strains were isolated from nasal swab specimens obtained from all infected pigs. Postmortem examination revealed fibrinopurulent meningitis, polyserositis, and polyarthritis in pigs inoculated with strain D-282; this strain was isolated from the cns, serosae, visceral organs, heart, and joints. Whereas strains D-282 caused several pathologic changes, strain T-15, isolated from the lungs, caused only pneumonia. Both strains were isolated from the tonsils of all pigs. Virulence differed distinctly between the mrp-positive and the mrp-negative strains.
Effect of prostaglandin F2α on adrenal-produced steroid hormones in cows
Authors: Watson Elaine D. , Hinrichs K. 
Published: February 2025

SUMMARY
Ovariectomized, nonlactating cows were treated with im injections of either physiologic saline solution or prostaglandin f2α. Plasma concentrations of cortisol increased significantly by 30 to 60 minutes after injection of prostaglandin f2α, but there were no significant increases in plasma concentrations of estradiol, progesterone, or testosterone. After saline solution treatment, there were no increases in any of the hormones measured.
Application of a Hall-effect transducer for measurement of tendon strains in horses
Authors: Stephens Paul R. , Nunamaker David M. , Butterweck Diane M. 
Published: February 2025

SUMMARY
Custom-designed Hall-effect strain sensors (hes) were implanted surgically onto the superficial digital flexor tendons of the forelimbs of 4 adult Thoroughbreds. Strains were recorded at various gaits, using a portable amplifer and fm cassette recorder. Strain calculations used the original length (l) as the hes position with the forelimb in the relaxed neutral position during anesthesia. A characteristic deflection in the strain cycle recording was confirmed to correspond to initial hoof contact with the ground (heel strike) by simultaneous recording of weight bearing via a footswitch. Heel strike was used as the reference point to determine the magnitude of strain change during weight bearing and nonweight bearing under various conditions. The weight-bearing strains (heel strike to maximal strain) recorded in 2 horses (with a rider) were 3.1% and 7.6% at the walk, 6.5% and 10.1% at the trot, and 11.5% and 16.6% at the gallop. Strain rate during tendon loading at the gallop was approximately 200%/s. The magnitude of strain change during nonweight bearing (minimal strain to heel strike) was smaller than during weight bearing, but also increased with faster gaits. In 3 horses led at the walk and trot, modest increases in hoof angle (baseline, 52°) resulted in small increases in the magnitude of strain change during weight bearing at the trot, but the magnitude of strain change at the walk was not affected. Results of the study indicated that the hes can be successfully adapted to provide continuous strain measurement without subjective signs of discomfort or lameness in horses during or after instrumentation.
Effects of xylazine and/or butorphanol or neostigmine on myoelectric activity of the cecum and right ventral colon in female ponies
Authors: Rutkowski Judith A. , Ross Michael W. , Cullen Kenneth 
Published: February 2025

SUMMARY
Effects of xylazine HCl (0.5 mg/kg of body weight, iv) and/or butorphanol tartrate (0.04 mg/kg, iv) or neostigmine methylsulfate (0.022 mg/kg, iv) on myoelectric activity of the cecum and right ventral colon were studied in 4 conscious female ponies. Eight bipolar Ag/AgCl electrodes were sequentially placed on the seromuscular layer of the cecum (6 electrodes) and right ventral colon (2 electrodes). Recordings began 30 minutes before and continued for 90 minutes after drug administration. Each drug or drug combination was studied on 2 occasions in each pony. Two major patterns of coordinated spike bursts were identified. A series of coordinated spike bursts began at the cecal base and was conducted to the cecal apex (pattern I). A series of coordinated spike bursts began at the cecal apex, traversed the cecum, cecocolic orifice, and right ventral colon and was termed a progressive pattern (pattern II).
Xylazine administration caused a significant decrease in patterns I and II for 20 minutes (P < 0.05). Butorphanol tartrate administration caused a significant decrease in the progressive pattern for 10 minutes (P < 0.05) without affecting the orally directed pattern. Administration of the combination of xylazine/butorphanol significantly decreased the frequency of pattern I for 40 minutes (P < 0.05) and pattern II for 30 minutes (P < 0.05). Neostigmine administration caused a significant increase in the frequency of pattern II for 30 minutes (P < 0.05) without affecting pattern I (P > 0.05). Changes in conduction velocity of pattern I or II or the duration of spiking activity were not significantly different because of any treatment.
Serum chemical profile of feeder pigs, as influenced by market stress and feeding regimen
Authors: Clemens E. T. , Schultz B. D. , Brumm M. C. , Jesse G. W. , Mayes H. F. 
Published: February 2025

SUMMARY
Two hundred eighty-eight crossbred feeder pigs were used in 2 trials to determine the effects of feed and/or water deprivation at an auction market, and the effects of restricting the intake of the receiving diet on their serum chemical profile. The study also was designed to assess the value of the serum chemical profile as a diagnostic data base for stress disorders in feeder pigs. Performance data indicated that feeder pigs provided water only at the auction facilities lost significantly more weight than did those provided feed and water. Feeder pigs deprived of both feed and water were not significantly different in body weight from either group. Several serum chemical values (creatinine, triglycerides, cholesterol, blood urea nitrogen, and lactate dehydrogenase) were significantly influenced by feed deprivation, but not by feed and water deprivation. However, only the serum creatinine values were significantly different after the 24-hour posttransport period. There were no significant differences in pig weight or serum chemical values 84 days after pigs had arrived at the finishing unit. The serum chemical profile, widely used in human medicine, appears not to provide a reliable marker for identification of short-term nutritional deprivation, nor for transport stress in feeder pigs.
Spectrophotometric method for differentiation of cardiac and hepatic lactate dehydrogenase activities in dogs
Authors: Aguilera-Tejero E. , Mayer-Valor R. , Gómez-Cárdenas G. 
Published: February 2025

SUMMARY
To differentiate the origin of high total lactate dehydrogenase (ld) activity in canine sera, a spectrophotometric method based on the preferential inhibition of cardiac ld isoenzymes by pyruvate was performed.
Comparison with the electrophoretic separation of ld isoenzyme activities and determination of the hydroxybutyrate dehydrogenase-to-ld ratio indicated that the method proposed gave a better discrimination between cardiac and hepatic ld activities than did the other tests.
Light and electron microscopy of keratinization in the laminar epidermis of the equine hoof with reference to laminitis
Authors: Budras K.-D. , Hullinger R. L. , Sack W. O. 
Published: February 2025

SUMMARY
The laminar epidermis (epidermis parietis) of hooves from 14 clinically normal horses, 6 months to 15 years old, was examined by light and electron microscopy and immunofluorescence to measure the contributions of this region to the formation of the hoof wall. By their progressive keratinization to form primary epidermal laminae, the secondary epidermal laminae ultimately contributed about 20% of the thickness of the hoof wall (as revealed in the white line [zona alba]). The keratinized, primary epidermal laminae were developed to a height of 4 mm during their proximodistal course, much of this obscured because of their basal portion being embedded in the cap horn epidermis. From evaluation of structural changes accompanying keratinogenesis in the cell and determination of the contribution of the laminar epidermis to the formation of laminar horn, cap horn, connecting horn, terminal horn, and the white line, we concluded that the sterile bed concept of a nongerminative role for the secondary epidermal laminae is no longer tenable.
Release of immunoreactive arachidonate metabolites by equine endometrium in vitro
Authors: Watson Elaine D. 
Published: February 2025

SUMMARY
The ability of equine endometrium to release prostaglandin (pg) f, pge2, and leukotriene (lt) b4 was studied in vitro, using endometrial tissue from diestrous mares. Because of the high cross-reactivity of the pgf antiserum with pgf1α and with pgf2α, results were quoted as total immunoreactive pgf. Significant concentrations of these arachidonate metabolites were released into tissue culture medium between 1 and 24 hours of incubation. Significantly higher concentrations of pgf, but not of pge2 or ltb4, were released from endometria of mares with chronic endometritis than from genitally normal mares. Prostaglandin F was released only in low concentrations from the endometrium of a mare with pyometra, but concentrations of pge2 and ltb4 were similar to those of genitally normal mares.
Evaluation of normal triiodothyronine and tetraiodothyronine concentrations in llamas (Lama glama)
Authors: Smith Bradford B. , Pearson Erwin G. , Leon Juan 
Published: February 2025

SUMMARY
Basal serum triiodothyronine (T3) and tetraiodothyronine (T4) concentrations have not been established for the llama (Lama glama). In addition, changes in T3 and T4 concentrations in response to thyroid-stimulating hormone (tsh) administration have not been determined, making clinical evaluation of problems referable to thyroid dysfunction difficult. In study 1, basal T3 and T4 concentrations were determined in serum samples collected 132 clinically healthy llamas. The llamas were allotted to 3 groups: mature intact or neutered males (group I, n = 25), nonpregnant sexually mature females (group II, n = 21), and pregnant females (group III, n = 86). A mean concentration and a 95% confidence interval were computed for each group. An analysis of variance (anova) indicated that a single confidence interval range (0.45 to 4.18, mean = 1.37 ng T3/ml) adequately defined the normal T3 concentrations for all groups. An anova indicated that the T4 concentrations for the female populations (groups II and III) could be combined with a normal confidence interval range of 39 to 204 ng/ml (mean = 88 ng/ml), whereas a separate range (70 to 220 ng/ml, mean = 124 ng/ml) was determined for the male population. An anova indicated that a single confidence interval range (0.0066 to 0.0321, mean = 0.0146) adequately defined the normal T3/T4 ratio for all groups.
In study 2, T3 and T4 concentrations were evaluated in 10 healthy llamas immediately preceding and at 2, 4, 6, 8, and 24 hours after the iv administration of 3 IU of tsh/ 44 kg of body weight. The T3 and T4 concentrations were significantly higher by 2 hours after tsh administration of both groups. Peak T3 and T4 concentrations were observed at 4 and 8 hours, respectively, after tsh administration. When normalized with respect to serum T3 concentrations in samples collected immediately prior to tsh administration, the maximal increase in predicted T3 concentration was 4.06-fold (80% confidence interval range = 2.99- to 5.50-fold) at 4 hours after tsh administration. The maximal increase in predicted normalized T4 concentration was 2.32-fold (80% confidence interval range = 1.76- to 3.05-fold) at 8 hours after tsh administration. The tsh-stimulated increases in T3 and T4 concentrations st 4 hours were clearly distinguishable from values in samples obtained before tsh administration.
Effect of zearalenone on early pregnancy in guinea pigs
Authors: Long Gerald G. , Diekman Mark A. 
Published: February 2025

SUMMARY
Female guinea pigs were tested to determine whether they could serve as a model of zearalenone (zen) toxicosis during early pregnancy, as observed in domestic swine. Only 1 of 4 female guinea pigs that were given 21 mg of zen/kg of body weight orally during the first 8 days after mating was pregnant when examined 22 days after mating. Guinea pigs that were given 7 or 14 mg of zen/kg had normal fetal development. Serum concentrations of progesterone were < 12 ng/ml in all guinea pigs 8 and 15 days after mating. Serum concentrations of progesterone were > 100 ng/ml in pregnant guinea pigs on day 22, but remained < 12 ng/ml in nonpregnant guinea pigs.
Three of 5 guinea pigs treated with 20 mg of zen/kg and only 1 of 4 guinea pigs given 30 mg of zen/kg on days 1 to 3 after mating were pregnant 22 days after mating. Female guinea pigs treated with 20 or 30 mg of zen/kg on days 4 to 5 or 6 to 8 after mating and female guinea pigs treated with 60 or 90 mg of zen/kg on days 4 and 5 after mating had normal pregnancies. Serum concentrations of progesterone were < 10 ng/ml in all guinea pigs on day 15 and remained low on day 22 only in nonpregnant guinea pigs.
Pregnancy in domestic swine is disrupted by zen treatment on days 7 to 10 after mating, when embryos are migrating within the uterus, analagous to days 4 to 5 after mating in guinea pigs. Guinea pigs responded to the estrogenic effects of zen on early pregnancy in a manner similar to that seen in other rodents and dissimilar to that demonstrated by swine. Hence, despite its prolonged estrous cycle in comparison with other rodents, the guinea pig does not serve as a model for zen toxicosis in swine.
Relationship of plasma gastrin immunoreactivity and gastroesophageal sphincter pressure in clinically normal dogs and in dogs with previous gastric dilatation-volvulus
Authors: Hall Jean A. , Twedt David C. , Curtis Charles R. 
Published: February 2025

SUMMARY
Fasting and postprandial gastroesophageal sphincter pressure (gesp) and plasma gastrin immunoreactivity were measured in 6 dogs from 9 through 60 months after treatment for and recovery from gastric dilatation-volvulus (gdv). The gesp was not significantly increased in these dogs, compared with that in clinically normal dogs in either the fasting or postprandial state. Corresponding plasma gastrin immunoreactivity was not significantly increased in dogs of the gdv-recovered group, compared with that in clinically normal dogs (fasting or postprandial). An exaggerated increase in gesp in response to food-induced gastrin release was not observed in dogs of the gdv-recovered group.
Exogenously administered pentagastrin (3-μg/kg bolus, iv) increased fasting gesp in clinically normal dogs over a 4-minute test period (P = 0.01). Gastric distention in response to oral administration of isosmolar saline solution (500 ml) did not significantly increase gesp or plasma gastrin immunoreactivity in clinically normal dogs. In anesthetized clinically normal dogs, gastric distention in response to use of balloons filled to exert intragastric pressure of 30 mm of Hg also did not cause significant increase in plasma gastrin immunoreactivity. Increased gesp, secondary to hypergastrinemia or gastric distention, is an unlikely cause of eructation failure in dogs with gdv.