bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the microcirculation of the equine jejunum and ascending colon after ischemia and reperfusion
Authors: Dabareiner Robin M. , Snyder Jack R. , Sullins Kenneth E. , White Nathaniel A. , Gardner Ian A. 
Published: January 2024

Summary
Intramural vascular patterns of the jejunum and colon were evaluated during ischemic strangulation obstruction (iso, 70 minutes) and subsequent reperfusion (60 minutes) in 7 adult anesthetized horses. Microvasculature of experimental and control segments was described by comparison of results from microangiography, light microscopy, and scanning electron microscopy of vascular replicas. Experimental and control segments with isolated vascular arcades were removed either immediately after the experimental period or after 60 minutes of reperfusion. Blood was flushed from the vascular system by use of isotonic NaCl, and the segments were divided. Half of each segment was perfused with a modified radiopaque medium for microangiographic evaluation, and half was perfused with dilute methylmethacrylate to create a vascular replica to be studied by scanning electron microscopy. Microangiographic section also were evaluated for histologic changes.
Microvasculature of jejunal control segments and all colon segments was similar to described normal microvasculature of the equine jejunum and ascending colon. In jejunal iso segments, intramural perfusion was redistributed away from the mucosa. In the villi, the central arteriole was short and convoluted and the subepithelial capillaries were not filled. The submucosal vessels and crypt capillaries were congested, compared with those of controls, and the serosal vessels were not filled in the ischemic segments. Histologic grade II-III mucosal lesion was seen in jejunal iso segments. Reperfused jejunal segments had a transmural hyperemic response, and previously unfilled capillaries were observed in all intestinal layers. After reperfusion, the mucosal lesion progressed to grade III-IV and a cellular infiltrate and edema formation were observed in the serosa.
The intramural vasculature of the ischemic and reperfused colon remain unchanged. Minimal histologic damage was observed in the colon after 70 minutes of iso or after 60 minutes of reperfusion.
Cardiorespiratory effects of intravenous bolus administration and infusion of ketamine-midazolam in dogs
Authors: Jacobson John D. , Hartsfield Sandee M. 
Published: January 2024

Summary
Twelve healthy dogs were used to determine the cardiorespiratory effects of iv administered ketamine (10 mg/kg of body weight) and midazolam (0.5 mg/kg). Half the dogs received a ketamine-midazolam combination (k-m) as a bolus over 30 seconds and the other half received the k-m as an infusion over 15 minutes. Induction of anesthesia by use of k-m was good in all dogs. Ketamine-midazolam combination as a bolus or infusion induced minimal cardiorespiratory effects, except for significant (P < 0.05) increases in mean heart rate and rate-pressure product. The increase in heart rate was greater in dogs of the infusion group. Mild and transient respiratory depression was observed in dogs of both groups immediately after administration of k-m, but was greater in dogs of the bolus group than in dogs of the infusion group. Duration of action of k-m for chemical restraint was short. Salivation and defecation were observed in a few dogs. Extreme muscular tone developed in 1 dog after k-m bolus administration.
Technique for prolonged, minimally invasive monitoring of intragastric pH in ponies
Authors: Baker Simon J. , Gerring E. Lawrence 
Published: January 2024

Summary
Intragastric pH monitoring was investigated in ponies. In cadaver stomachs, close contact with the mucosa led to high pH readings if nonweighted electrodes were used. However, pH recorded by weighted electrodes was markedly less affected by mucosal contact (P < 0.001). The latter were used for subsequent trials. In vivo, high correlations were found between pH recorded by weighted electrodes with or without a wire guard to prevent mucosal contact (correlation, r = 0.866; P < 0.001). Readings from each correlated well with those from simultaneous gastric aspirates (r = 0.774 and r = 0.807, respectively; P < 0.001 for both correlations). Plain electrodes recorded more highly variable (temporally heterogeneous) pH than did guarded electrodes. In vitro, trials using equine gastric fluid indicated that this resulted from greater responsiveness of the plain electrode. In vivo, episodes of nearly neutral pH were a common feature, and high pH correlated with intensely yellow-green, neutral fluid in the stomach (rank correlation, ρ = 0.626; P < 0.01). Concentration of bile acids did not correlate with pH or color score (ρ = −0.158 and ρ = 0.076, respectively). Causes of the episodes could include salivary influx, duodenogastric reflux, and variable gastric acid secretion. Pentagastrin infusion (0.6 μg/kg of body weight/h) reduced intragastric pH (P = 0.018), but episodes of neutrality still occurred. Experiments in fed ponies indicated possible existence of a stable pH gradient, from neutral dorsally to heterogeneous and more acidic ventrally. Care was required in the rational choice of summary variables for expression of monitored pH data. Of the frequency distributions of 3 summary variables assessed in this study (mean, median, and percentage of data > pH 4), only that of the mean approached normality. Thus, use of the mean may allow analysis by parametric statistical methods.
Intragastric pH monitoring was found to be a useful technique. Episodes of increased pH were often identified. These may represent episodic duodenogastric reflux.
Pulsatile secretion of luteinizing hormone and progesterone in mares during the estrous cycle and early pregnancy
Authors: Perkins Nigel Ross , Threlfall Walter Ronald , Ottobre Joseph Steven 
Published: January 2024

Summary
Existence of ultradian variation in serum progesterone concentration and the relation between progesterone and luteinizing hormone (lh) secretory patterns were investigated in nonpregnant and pregnant mares. Blood samples were taken every 15 minutes for a 24-hour period on day 8 of the estrous cycle and day 18 of pregnancy, respectively. Progesterone and lh concentrations were determined by radioimmunoassay. Progesterone was secreted in pulsatile manner in nonpregnant and pregnant mares. Luteinizing hormone also was secreted in a pulsatile manner in both groups of mares. There was little temporal relation between lh and progesterone pulses in either pregnant or nonpregnant mares.
Pharmacokinetics of and serum thromboxane suppression by flunixin meglumine in healthy foals during the first month of life
Authors: Semrad Susan Diane , Sams Richard Alvin , Ashcraft Susan Marie 
Published: January 2024

Summary
Age and species reportedly affect the pharmacokinetic variables of nonsteroidal anti-inflammatory drugs. We determined the effect of age on flunixin pharmacokinetic variables in foals during the first month of life. We also estimated the physiologic activity of the drug in neonatal foals by determining the effect of flunixin on thromboxane production during clotting of blood taken from the foals. Flunixin disposition and clearance were determined after iv administration of 1.1 mg of drug/kg of body weight to 5 healthy foals when they were 24 to 28 hours, 10 to 11 days, and 27 to 28 days old. The area under the curve (2,471 μg·min/ml), mean residence time (477 minutes), and zero-time intercept of the elimination phase (4,853 ng/ml) were significantly (P = 0.05) greater, the elimination half-life (339 minutes) and slope of the elimination phase (0.002 L/min) were significantly (P = 0.05) longer, and total body clearance (0.482 ml/min/kg) and zero-time intercept for the distribution phase (2,092 ng/ml) were significantly (P = 0.05) lower at 24 to 28 hours. At each age, a biexponential equation was best fitted to the plasma flunixin concentration from each foal. Thromboxane B2 production during clotting of blood was significantly (P = 0.05) suppressed for 12 hours after flunixin meglumine administration at all ages. Therefore, it appears that although age does alter the disposition and elimination of flunixin in neonatal foals, this effect may be of little consequence because the drug's physiologic activity in foals appears similar to that in mature horses.
Duration of QT interval in clinically normal dogs
Authors: Oguchi Yoko , Hamlin Robert L. 
Published: January 2024

Summary
The QT interval is the period from onset of the QRS complex to the end of the T wave. The QT interval is useful for monitoring drug (eg, quinidine) and electrolyte (eg, calcium) effects on the heart. It depends principally on heart rate (hr), and the relationship between QT interval and hr has been expressed for human beings and for dogs. The purpose of the study reported here was to quantify that relationship for dogs and to assess whether body weight also influenced QT interval. The ecg was recorded from 17 dogs, ranging in weight between 7 and 25 kg. Dogs were anesthetized with fentanyl/droperidol/ketamine, and hr was accelerated by administration of graded doses of atropine. A significant relationship was not found between QT interval and body weight. Despite changes in hr during sinus arrhythmia, a significant relationship was not found between QT and RR intervals. The QT interval vs hr accelerated by atropine was analyzed for all dogs and for small (7 to 10 kg, n = 5), medium (10 to 20 kg, n = 7), and large dogs (20 to 25 kg, n = 5). Equations relating QT interval to mean hr were calculated for each group. Our data may serve as a baseline with which to compare QT intervals from dogs with heart disease and/or electrolyte imbalance.
Comparison of two ultralente insulin preparations with protamine zinc insulin in clinically normal cats
Authors: Broussard John D. , Peterson Mark E. 
Published: January 2024

Summary
The absorption kinetics and glycemic effects of 3 long-acting insulin preparations (protamine zinc beefpork insulin, ultralente beef-pork insulin, and ultralente human insulin) were evaluated in 9 healthy, adult, domestic shorthair cats (6 males, 3 females). A triple crossover study was performed, in which the serial serum concentrations of insulin and glucose were determined over a 24-hour period after SC administration of the 3 insulin preparations (dosage, 1.0 U/kg of body weight) at 3-week intervals. A control study was also performed in 4 of the cats by serially collecting samples for insulin and glucose determinations after administration of insulin diluent. After administration of protamine zinc insulin (pzi), mean (± sem) serum insulin concentration increased significantly (P < 0.05) above baseline, reached a peak value (484 ± 287 pmol/L) at 1 hour, and remained significantly (P < 0.05) higher than baseline at 24 hours. After administration of ultralente human insulin, the serum insulin curve was similar to that obtained after pzi administration, but mean serum insulin concentration took longer to peak (538 ± 177 pmol/L at 4 hours). After administration of ultralente beef-pork insulin, mean peak serum insulin concentration was lower (220 ± 54 pmol/L, not statistically significant) than that obtained after administration of pzi and ultralente human insulins; it then decreased to values statistically indistinguishable from baseline by 16 hours. The area under the serum insulin concentration curve for pzi (5,063 ±681 pmol • h/L) and ultralente human insulin (4,138 ± 439 pmol • h/L) was significantly (P < 0.05) larger than that for ultralente beef-pork insulin (2,378 ± 561 pmol • h/L). Serum glucose concentration decreased after administration of all 3 insulins, but the decrease was not different from that observed after diluent (control) administration. Results of this study indicate that differences may exist between absorption of pzi, ultralente human, and ultralente beef-pork insulins. Of the 2 ultralente insulin preparations, human insulin appears better absorbed than beef-pork insulin, but these findings need to be confirmed in cats with naturally acquired diabetes mellitus.
Modulation of Fc receptors for IgG on bovine polymorphonuclear neutrophils by interferon-γ through de novo RNA transcription and protein synthesis
Authors: Worku Mulumebet , Paape Max J. , Marquardt Warren W. 
Published: January 2024

Summary
Polymorphonuclear neutrophils (pmn) from 4 cows were preincubated (30 minutes, 37 C) in either actinomycin D (100 μg/ml) or puromycin (10 μg/ ml), inhibitors of mRNA transcription and protein translation, or in medium 199. The pmn were incubated for a further 4.5 hours in medium containing 100 U of recombinant bovine interferon-γ (rbolfn-γ). The pmn were then incubated with bovine IgG1, IgG2, IgM, or aggregated IgG (algG; 4 C, 12 hours) for flow cytometric analysis, using fluoresceinated is-otype-specific antibody. The percentage of pmn binding the ligand and the logarithmic mean fluorescent channel (lmfc), an indicator of the amount of receptor (R) expression, were recorded. Competitive inhibition of ligand binding was measured by incubating pmn with fluoresceinated IgG2 in the presence or absence of 100-fold excess of IgG1, IgG2, and aIgG. Activation with rboIfn-γ induced a 4.5-fold increase in binding of IgG1 and a fivefold increase in lmfc for IgG2. These increases were inhibited by actinomycin D and puromycin. Percentage of pmn binding aIgG decreased after activation by rboIfn-γ. Interferon-γ treatment did not affect binding or lmfc of IgM. However, binding of IgM was reduced by treatment with actinomycin D. Binding of fluoresceinated IgG2 was inhibited by unlabeled IgG1, IgG2, and aIgG. Results indicate that bovine pmn Fc receptors (FcR) for IgG1 and IgG2 were rboIfn-γ inducible, that induction required de novo transcription and translation, that a heterogeneous population of FcR exist on bovine pmn, and that IgG1 and IgG2 share a common FcR. Further, bovine pmn are capable of gene activation and are responsive to changes in their environment, thus being amenable to modulation for effective pathogen destruction.
Safety, efficacy, and effects on copper metabolism of intrareticularly placed selenium boluses in beef heifer calves
Authors: Maas John , Peauroi John R. , Weber Dale W. , Adams Frank W. 
Published: January 2024

Summary
Intrareticularly placed sustained-release selenium boluses were administered to 1 group of selenium-deficient heifer calves (n = 16), and a second group (n = 16) was left as nontreated controls. Age range for all calves was 83 to 156 days. These boluses release 3 mg of selenium each day, as sodium selenite. Measurements of blood selenium concentration, plasma copper concentration, hepatic copper concentration, and body weight were made over a 188-day study. The treated group of calves had significantly higher mean blood selenium concentration at posttreatment days 68 (P < 0.0001), 112 (P < 0.0001), and 188 (P < 0.005) than did the control group. Mean blood selenium concentration in the treated calves was > 0.10 μg/ml for 188 days. These boluses were observed to be clinically safe; signs of selenium toxicosis were not detected and untoward effects were not seen in the selenium-treated calves. There were no differences between control and treatment groups with respect to mean hepatic copper concentration or mean plasma copper concentration. There were no observed differences between the control and treatment groups with respect to weight gain during the study.
Concentration and molecular weight distribution of hyaluronate in synovial fluid from clinically normal horses and horses with diseased joints
Authors: Tulamo Riitta-Mari , Heiskanen Tiina , Salonen Matti 
Published: January 2024

Summary
High molecular weight (mw) hyaluronate (ha) is an integral part of synovial fluid (sf), regulating many Important physiologic and pathophysiologic mechanisms. Many of its effects depend on, or are reflected in. the concentration and mw of ha. High-performance liquid chromatography was used to assess simultaneously the concentration and mw of ha in sf obtained from horses with various arthritides: acute traumatic arthritis; chronic traumatic arthritis, including degenerative joint disease (djd); and infectious arthritis. The size-exclusion column was calibrated, using appropriate ha concentration and mw standards, before the high-performance liquid chromatographic assays of the sf samples.
Calibration of the column disclosed that the maximal limit for mw estimation of ha was around 3 million. In control joints, mw of ha ranged from 2 to 3 × 106 (mean 2.5 × 106) and did not differ significantly from mw of ha in sf from horses with acute or chronic traumatic arthritis (mean 2 × 106; range 1.5 to 3 × 106). Interestingly, a small amount of ha of moderately high mw (approx 1 to 1.5 × 106) was detected in chromatograms of sf from infected joints. This degree of polymerization of sf ha was significantly (P < 0.01) lower, compared with that for control joints.
There was no difference in mean (± sd) concentration of ha between control joints and joints with acute or chronic traumatic arthritis (0.33 ± 0.12 g/L vs 0.18 ± 0.03 g/L. or 0.23 ± 0.12 g/L.), indicating that sf ha concentration probably should not be used as a diagnostic marker for the condition. However, the sf ha concentration was significantly (P < 0.01) lower in joints with infectious arthritis (0.07 ± 0.03 g/L) and in the joints with radiographic evidence of djd (0.12 ± 0.01 g/L), compared with control joints.
Effect of ergovaline, lolinc, and dopamine antagonists on rat pituitary cell prolactin release in vitro
Authors: Strickland James R. , Cross Dee L. , Birrenkott Glenn P. , Grimes Larry W. 
Published: January 2024

Summary
Cultured rat pituitary cells were studied to: determine the effects of ergovaline and loline on in vitro prolactin release; delineate the agonistic activity of these alkaloids at the D2 dopamine receptor, using 2 selective D2 dopamine receptor antagonists; and compare the efficacy of 2 dopamine receptor antagonists in reversing effects of the treatments on in vitro prolactin secretion. Ergovaline reduced in vitro prolactin release by at least 40% (P < 0.05) at concentrations of 10−4, 10−6, and 10−8M However, loline reduced (P < 0.05) prolactin release only at the highest concentration, 10−4 M. Two standard dopamine agonists, dopamine and α-ergocryptine, were used to verify that the inhibitory control mechanisms of in vitro prolactin release were intact. Both compounds reduced prolactin release by at least 40% for concentrations of 10−4, 10−6, or 10−8M. Selective D2 dopamine receptor antagonists (10−6M), domperidone and sulpiride, reversed (P < 0.05) the effect of loline on in vitro prolactin release. However, only domperidone (10−6M) was able to reverse (P < 0.05) the effect of ergovaline and only at the lowest ergovaline concentration (10−8M). Domperidone was more effective (P < 0.05) in reversing the prolactinsuppressing effect of α-ergocryptine than was sulpiride. The dose-response curve for domperidone (cubic fit, P < 0.0001) indicated a threshold concentration (10−7M) for reversal of a-ergocryptine's (10−8M) effect on prolactin release. However, at similar concentration of sulpiride (quadratic fit, P < 0.007), a threshold level was not obtained. These data indicate that ergovaline and loline may act as D2 dopamine receptor agonists. Additionally, domperidone seems to be a more potent drug for reversal of the alkaloids’ hypoprolactinemic effect in vitro than does sulpiride.
Isolation and partial polypeptide characterization of bovine neutrophil plasma membranes
Authors: Salgar Shashikumar K. , Paape Max J. , Alston-Mills Brenda 
Published: January 2024

Summary
The neutrophil plasma membrane has a major role in migration, phagocytosis, and destruction of microorganisms. Neutrophils isolated from blood and mammary secretions were homogenized, and the plasma membrane fraction was isolated on discontinuous sucrose gradient (20, 32, and 50%). Purity of plasma membrane preparation was determined by use of marker enzyme analysis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) of the membrane proteins was performed under reducing conditions for polypeptide characterization. The membrane proteins were also labeled with 125I externally, using 1,3,4,6-tetrachloro-3α-6α-diphenylgly-couril, and proteins were separated by sds-page and autoradiographed.
Compared with whole cell homogenate, the plasma membrane fraction obtained at the 20/32% interface was enriched for the marker enzymes, 5′-nucleotidase (16-fold), alkaline phosphatase (5.5-fold), and total phosphatase (26-fold). The membrane fraction had minimal specific activity for β-glucuronidase (0.4-fold), compared with whole cell homogenate. Plasma membrane protein yield was about 500 μg/ 109 bovine blood neutrophils. The sds-page of plasma membrane proteins revealed 25 protein bands, of which 13 were major bands. There were 3 distinct bands (18, 36, and 65 kd) in the plasma membrane-enriched fraction (20/32 interface) that were not seen in other fractions (30/50% and pellet). Further, 125I-labeling identified 5 distinct protein bands (205, 140, 65, 35, and 30 kd). Blood and mammary neutrophils had similar polypeptide patterns, except that 36- and 65-kd bands were more prominent for blood neutrophils than for mammary neutrophils.
Hemorheologic alterations induced by incremental treadmill exercise in Thoroughbreds
Authors: Geor Raymond J. , Weiss Douglas J. , Smith Clark M. 
Published: January 2024

Summary
Hemorheologic alterations induced by incremental treadmill exercise were examined in 5 Thoroughbreds. Blood viscosity; pcv; rbc filterability, density gradient profile, and shape; serum and rbc electrolyte concentrations; and plasma total solids and lactate concentrations were measured before exercise, at treadmill speeds of 9 and 13 m/s, and 10 minutes after exercise. Exercise was associated with significant (P < 0.05) increases in pcv, blood viscosity, and plasma total solids concentration. After adjustment of pcv to 40% by adding or removing each horse's own plasma, blood viscosity remained significantly greater in the sample obtained at 13 m/s, compared with that in samples taken at rest. Filterability of rbc was significantly decreased at 13 m/s, compared with values from other sampling times. During exercise, a significantly greater proportion of the rbc were less dense and were found in the upper layers of the rbc density gradient profile, compared with resting values. This change was associated with a significant increase in rbc mean cell volume. Rapid increases in serum sodium and potassium concentrations during exercise were accompanied by significant increases in rbc potassium and chloride concentrations. This study revealed a consistent pattern of hemorheologic alterations associated with exercise in Thoroughbreds, suggesting that multiple hemorheologic tests are needed to adequately define these complex alterations during exercise in horses.