Topic:Heparin
Heparin is an anticoagulant medication used in horses to prevent and treat blood clot formation. It functions by activating antithrombin III, which inhibits thrombin and factor Xa, key components in the blood coagulation cascade. Heparin is commonly administered in equine medicine to manage conditions such as thrombophlebitis, laminitis, and disseminated intravascular coagulation. The dosage and administration of heparin must be carefully monitored to avoid complications such as hemorrhage. This page compiles peer-reviewed research studies and scholarly articles that explore the pharmacokinetics, therapeutic applications, and potential side effects of heparin in equine practice.
[Experiences with long-term intravenous therapy using teflon catheters in 80 horses]. In a retrospective study the tolerance to Teflon coated catheters in long-term intravenous medication was evaluated in 80 horses. Catheters were inserted into the jugular vein and remained there for 3 to 30 days (average 8.6 days). Catheters were flushed using an heparinized solution after each medication administration. The site of catheter placement was evaluated daily for swelling, pain and venous distensibility respectively. Swelling at the site of insertion was noted in 10 horses, a small subcutaneous abscess formation was identified in one horse. Fourteen sonographic evaluations were per...
Capacitation-like membrane changes and prolonged viability in vitro of equine spermatozoa cultured with uterine tube epithelial cells. Reliable capacitation of equine spermatozoa has been a major obstacle in the development of equine in vitro fertilization. Experiments were done to compare in vitro capacitation of equine spermatozoa by use of heparin/caffeine, calcium ionophore, uterine tube epithelial cell (UTEC)-conditioned medium, and direct culturing of spermatozoa with UTEC (coculturing). Capacitation-like changes, as determined by chlortetracycline membrane staining patterns, developed with UTEC-conditioned medium and coculturing, equivalent to that with calcium ionophore. Both of these treatments induced more (P < 0.05...
Hepatic lobe torsion as a cause of colic in a horse. A 14-year-old Arabian gelding was examined for colic. An exploratory celiotomy was subsequently performed and the left lobe of the liver was found to be twisted. The lobe was resected using a TA-90 surgical stapling instrument. Histologic examination of the resected liver indicated portal vein and sinusoid dilation and congestion with blood. There were focal areas of necrosis and bacterial cocci and rods throughout the section. The histologic findings were consistent with hepatic lobe torsion. After surgery, the horse was treated with broad spectrum antibiotics, anti-inflammatory drugs, hepari...
Effect of temperature, duration of storage and sampling procedure on ammonia concentration in equine blood plasma. The effect of storage duration at different storage temperatures on the plasma ammonia concentration of equine EDTA whole blood, EDTA plasma and heparin plasma samples was investigated. Further, the effect of jugular vein compression before and during blood sampling on the plasma ammonia values was evaluated. In EDTA whole blood kept at 4 degrees C there was no significant increase of ammonia content after 6 hours of storage, whereas the increase was already significant 3 hours after collection if the EDTA whole blood was kept at 20-22 degrees C. EDTA plasma samples stored at 20-22 degrees C, ...
Assay for endogenous heparin in plasma of livestock using a synthetic chromogenic substrate. The levels of endogenous heparin in the plasmas of horses, cows, sheep and pigs were determined with the use of synthetic chromogenic substrate benzoyl-isoleucyl-glutamyl-glycyl-arginyl-p-nitroanilide (S-2222). The lowest heparin concentrations were stated in cattle plasma, the highest ones in the plasma of pigs.
Microvascular circulation of the descending colon in horses. The microvascular circulation of the descending colon was studied in 5 adult horses, using microangiography and light microscopy combined with gross studies and scanning electron microscopy of vascular replicas. After heparinization, horses were euthanatized, and 3 segments of the descending colon and its mesentery containing 1 vascular arcade were removed from each horse. The fecal balls were gently massaged from the lumen, and the blood was flushed free of the circulation with isotonic NaCl. In 5 segments, the vascular system was injected with a modified radiopaque medium and evaluated radio...
Microvascular circulation of the small intestine in horses. The microvascular anatomic features of the small intestine was described by correlating results of microangiography, light microscopy, gross studies, and scanning electron microscopy of vascular replicas in 14 horses. After heparinization, the horses were euthanatized, a length of jejunum was transected, and blood was flushed free of the circulation, using isotonic NaCl solution. In six horses, the circulatory system was perfused with a modified radiopaque medium and evaluated radiographically. These sections were then evaluated by standard histologic methods. Sections from 8 horses were perfu...
Disseminated intravascular coagulation associated with colic in 23 horses (1984-1989). Disseminated intravascular coagulation (DIC) secondary to colic was diagnosed in 23 horses. Each horse was categorized retrospectively as to the cause of the colic based on surgical and/or necropsy findings: group 1 consisted of 14 horses with compromised intestine that required resection and anastomosis; group 2 consisted of 3 horses with nonstrangulating intestinal displacement and/or impactions; and group 3 consisted of 6 horses with colic associated with enteritis and/or colitis. Horses were considered to be affected with DIC if at least three of five hemostatic parameters were significant...
Effects of heparin treatment on colonic torsion-associated hemodynamic and plasma eicosanoid changes in anesthetized ponies. Large colon torsion frequently is a fatal condition in horses. The purpose of the study reported here was to determine systemic arterial pressure, plasma eicosanoid concentrations, colonic blood flow, vascular resistance, tissue pH, and morphologic features associated with large colon torsion and detorsion, and to evaluate the effects of sodium heparin (80 IU/kg of body weight, IV) treatment on these values. Values were determined in 20 anesthetized ponies that were randomly assigned into 4 equal groups: control; control/heparin; torsion; torsion/heparin. Torsions were created by a 720 degrees...
Low dose calcium heparin in horses: plasma heparin concentrations, effects on red blood cell mass and on coagulation variables. Low dose calcium heparin was administered subcutaneously at 12 hourly intervals to six healthy horses at an initial dose of 150 iu of heparin/kg bodyweight (bwt) and at a maintenance dose of 120 iu/kg bwt. All injections were given at 0900 and 2100 h. Blood samples for monitoring plasma heparin concentrations were obtained prior to, at 2 hourly intervals for 84 h (treatment period), and at Hours 24, 32, 48 and 96 of the control period. Blood samples for monitoring red blood cell (RBC) mass, plasma antithrombin III activity (AT III), activated partial thromboplastin time (APTT), and thrombin ti...
In vitro fertilization of horse follicular oocytes matured in vitro. In vitro fertilizing ability of stallion spermatozoa was assessed using horse follicular oocytes matured in vitro. After collection, stallion spermatozoa were either: 1) washed and incubated in TALP medium with 3 mg/ml bovine serum albumin (BSA) and 10 micrograms/ml heparin for 4h, 2) washed and incubated in TALP with 3 mg/ml BSA for 3 h and cultured for a further 1 h with 1 mM caffeine and 5 mM dbcAMP, 3) washed and incubated in TALP medium with 3 mg/ml BSA at pH 7.9-8.2 for 2-4 h, or 4) diluted and incubated in TALP medium with 10 mg/ml BSA and 7.14 microM calcium ionophore A 23187 for 5-10 ...
Evaluation of heparin for prophylaxis of equine laminitis: 71 cases (1980-1986). The records of 71 horses with small intestinal disorders requiring surgical correction were disorders requiring surgical correction were reviewed to compare the prevalence of laminitis in those horses treated prophylactically with heparin and the prevalence of horses not treated with heparin. The prevalence of laminitis was 13% (9/71), and there was no significant difference (P less than 0.05) in the prevalence of laminitis between the 2 groups. The lack of significant benefit after treatment with heparin indicates that further work needs to be done on the equine coagulation system before hepa...
The effect of low dose heparin therapy on complication and survival rates in horses following exploratory celiotomy. A randomised, blind prospective study was performed to evaluate effects of low dose heparin therapy on complication and survival rates in 33 horses following exploratory celiotomy. Four horses had non-strangulating lesions and seven had strangulating lesions of the small intestine, 19 had non-strangulating lesions of the large intestine, and three had duodenitis-proximal jejunitis. Eighteen required an enterotomy or intestinal resection and anastomosis. Sixteen received heparin subcutaneously (66 iu/kg every 12 h) post operatively and 17 received a saline placebo for a mean of 3.7 days. There ...
Antithrombin III activity (residual thrombin activity) in plasma from non-medicated or heparinized horses. Two synthetic substrate assays (fluorometric and chromogenic) were used to measure antithrombin-III (AT-III) activity (residual thrombin activity) in non-medicated and heparin (sodium) treated horses. In 18 non-medicated horses the fluorometric substrate assay (FSA) values were similar to previous reports but they reflected inconsistent trends and larger deviations in the heparin-treated groups (Group 2: 40 and 100 U/kg IV, n = 6; Group 3: 240 U/kg IV, n = 5; Group 4: 80 U/kg IV followed by 160 U/kg SC, n = 8) when compared to the chromogenic substrate assay (CSA) values. The CSA values for th...
Comparison of the lipoprotein pattern of the horse, the pony and the lactating and non-lactating cow obtained by a combination of an ultracentrifugation and a precipitation technique. 1. The serum lipoprotein pattern was studied in four horses, four ponies and in three high producing lactating and three non-lactating cows. The lipoprotein pattern was estimated with a combination of the preparative ultracentrifugation and the heparin-manganese precipitation technique. 2. The lipid composition of the lipoproteins of horse, pony, lactating cow and non-lactating cow was determined. 3. In all three species more than 50% of serum total lipids was found in the HDL fraction. 4. The mean chylomicron fraction in horse and pony was 3.1%. In the cow it varied from 1.5 to 2.5%. 5. Betwe...
[Pathogenesis and drug therapy of acute laminitis in horses: a literature review]. Impairment of the microcirculation in the distal part of the foot is an important factor in the aetiology of equine laminitis. To prevent the development of chronic laminitis and the resulting complications, two new therapeutical principles were tested in the treatment of acute laminitis. Thrombosis which frequently occurs in the corium of the foot, could be controlled by administration of anticoagulants such as heparin. Alpha-receptor blocking agents such as phenoxybenzamine were used, to improve the peripheral blood flow. The use of these drugs and that of anti-inflammatory agents during the...
Dose-dependent plasma elimination of subcutaneously administered calcium heparin in horses. Pharmacokinetic parameters for subcutaneous low dose heparin in horses have been determined. Four groups of five and one group of eleven mature, healthy horses of various breeds were given single subcutaneous injections of 60, 80, 100, 125, and 150 units of calcium heparin/kg of body weight (U/kg) in the pectoral region. Jugular blood samples were collected prior to, and at hourly intervals for 12 h after injection. Heparin plasma concentrations were measured using a commercially available amidolytic assay. Peak concentrations 4 h after administration were 0.021 +/- 0.016 (mean +/- SD) units o...
Heparan sulfate proteoglycan from human and equine glomeruli and tubules. 1. Proteoglycans were isolated from human and equine glomeruli or tubules by guanidine extraction and anion exchange chromatography. 2. These proteoglycan preparations contained about equal amounts of heparan sulfate and chondroitin sulfates. 3. During the preparation of glomerular or tubular basement membranes the main part of proteoglycans (greater than 50%) was extracted in the salt extract. Chondroitin sulfate proteoglycan was mainly found in the water and salt extracts of glomeruli and tubules, heparan sulfate proteoglycan in the deoxycholate extracts and the basement membranes. 4. The gl...
Plasma heparin values and hemostasis in equids after subcutaneous administration of low-dose calcium heparin. Different doses of heparin were given to equids SC to establish 0.05 to 0.20 U of heparin/ml of plasma. Plasma heparin values and antithrombin III activities were assayed, using chromogenic substrate methods. Activated partial thromboplastin and thrombin times were determined, using conventional coagulation assays. Tests were run every hour (or every 2 hours for antithrombin III) for 12 hours from 5 groups of 5 equids each after single injection of 40, 60, 80, 100, or 125 U of calcium heparin/kg of body weight and from 11 equids after injection of 150 U of calcium heparin/kg. The smaller dose ...
Prevention of intraabdominal adhesions in ponies by low-dose heparin therapy. An ischemic bowel model was used to stimulate adhesion formation in eight ponies. Heparin (40 USP u/kg) or saline was administered intravenously at surgery and was continued subcutaneously every 12 hours for 48 hours to evaluate the efficacy of heparin in preventing intraabdominal adhesions. Ponies were euthanatized after 6 weeks, and postmortem examinations were performed. A statistically significant difference was found between the heparin-treated and the control groups. Adhesions developed in three of four control ponies, and adhesions did not develop in three of four heparin-treated ponies...
Heparin-induced agglutination of erythrocytes in horses. Heparin was administered subcutaneously 2 times a day for 4 days to 5 horses. An additional group of 5 horses was used as time-matched controls. Significant decreases in PCV, erythrocyte count, and hemoglobin concentration were observed during heparin therapy. The mean corpuscular volume (MCV) of the heparin-treated horses increased to a peak value of 66.1 fl on the last day of treatment. Erythrocyte creatine concentration and glucose 6-phosphate dehydrogenase activity increased moderately during the treatment. These data indicated that the rapid, profound increase in MCV during heparin therap...
Erythrocyte agglutination associated with heparin treatment in three horses. In vitro erythrocyte agglutination developed in 3 hospitalized horses receiving heparin treatment. The agglutination caused artifactual decreases in erythrocyte counts and increases in mean corpuscular volume (MCV) values. Treatment of cell suspensions with trypsin eliminated the agglutination and the changes in erythrocyte count and MCV. Similar abnormalities in erythrocyte counts and MCV have been reported in healthy horses treated with heparin and have been cited as evidence of hemolysis and regenerative anemia.
Equine endothelial cells in vitro. Certain in vitro culture conditions were determined for equine endothelial cells obtained from the aorta and pulmonary arteries. Cells were enzymatically isolated from the vessel lumen, using clostridial collagenase (2.5 mg/ml of Hanks's balanced salt solution) incubated at 37 C for 30 minutes. Cells were cultured in alpha minimum essential medium supplemented with plasma-derived and nonplasma-derived bovine fetal sera, endothelial cell-growth supplement, heparin, and antibiotics. Smooth muscle cell growth was not inhibited with nonplasma-derived animal sera, plasma-derived equine serum, or he...
Enhanced biliary bilirubin excretion after heparin-induced erythrocyte mass depletion. The effect of large-dose heparin therapy on erythrocyte mass depletion in ponies was investigated to determine whether stimulation of reticuloendothelial cell activity and catabolic function would be evidenced by enhanced catabolism of heme to bilirubin. Ponies with chronic external biliary fistula were used to examine biliary excretion of bilirubin both before and after heparin loading (107 U/kg, IV, plus 320 U/kg, subcutaneously) and at maintenance dosages of 320 U/kg given (subcutaneously) at 12 and 24 hours after initial loading with heparin. Results indicated that by 48 hours after ponies...
Production and biological properties of M-protein of Streptococcus equi. The production of M-protein antigen of Streptococcus equi was studied during in vitro growth in equine blood and in various media. Of 11 S equi strains studied, seven which had initially possessed 0.04 mg or less M-protein per 10 mg of streptococcal cell extract showed an increase in M-protein content after successive culture in heparinised horse blood. Maximum proliferation occurred in Todd-Hewitt (TH) medium with added 0.2 per cent w/v glucose when compared with TH medium alone or TH medium with 2 per cent w/v sucrose, starch, neopeptone or normal horse serum. The M-protein of these strains ...
Heparin anticoagulant therapy in equine colic. In horses with large bowel disease, those with circulating endotoxins but no evidence of altered hemostasis had a good prognosis for survival. Those with circulating endotoxins and evidence of altered hemostasis (fibrin degradation products) had a poor prognosis. Portal vein infusion of endotoxins over 24 hours caused hoof discomfort, evidenced by shifting of weight and standing with all 4 feet together, and a decreased hoof temperature. Clinical signs appeared within 30 minutes of initiation of infusion and subsided within 4 hours despite continued infusion. Long-term heparin therapy results ...
Reduction of the red blood cell mass of horses: toxic effect of heparin anticoagulant therapy. This study was designed to test the efficacy of heparin anticoagulant therapy in the horse and its effect on the formed elements of blood. Nine clinically normal, nontraumatized adult horses were subjected to 4 different heparin maintenance regimens (dosages of 320, 240, 160, and 40 U/kg of body weight). Porcine intestinal mucosa heparin (20,000 U/ml) was injected subcutaneously every 12 hours for 96 hours (total 9 times). A loading dose of one-third the maintenance dose was given IV just before the first heparin injection. Three control horses were given an equivalent volume of 0.9% saline so...
The concept of osmolality: its use in the evaluation of “dehydration” in the horse. Osmolality is an indication of the osmotic pressure of plasma and depends on the amount of solute and solvent (water) present. The mean (+sd) plasma osmolality of 100 clinically normal animals was 282 (+6) mOsm/kg using lithium heparin as anticoagulant. The equation, osmolality=1.86 (sodium + potassium) +glucose +blood urea nitrogen + 9, was found to predict only crudely plasma osmolality. The plasma sodium: osmolality ratio was 0.49. Water and electrolyte disorders are classified into 3 types based on the measurement of electrolytes and osmolality: (1) Hypertonic dehydration (true dehydration...
Changes in plasma progesterone levels during storage of heparinized whole blood from cow, horse, dog and pig. Progesterone concentrations in heparinized plasma harvested immediately after blood collection were compared with levels obtained after storage of the corresponding whole blood for 2 h, 4 h, 6 h, 1 day, 2 days and 5 days at room temperature and in a refrigerator. The blood was taken during the luteal phase from 4 dogs, 4 horses, 4 pigs and 8 cows. For 4 cows the storage time was extended to 9 and 20 days. No significant effect of whole blood storage time on plasma progesterone concentrations could be shown for dogs or pigs. For the horse a slight but significant decrease was demonstrated when ...