Diagnosis of disseminated intravascular coagulation in dogs admitted to an intensive care unit.

OBJECTIVE: To describe and evaluate hemostatic function in critically ill dogs with clinical signs of diseases that predispose to disseminated intravascular coagulation (DIC). DESIGN: Prospective case series. ANIMALS: 59 critically ill dogs (affected dogs) with clinical signs of diseases known to predispose to DIC and 52 clinically normal dogs (control dogs). PROCEDURE: Activated partial thromboplastin time (aPTT), prothrombin time (PT), thrombin clotting time (TCT), plasma fibrinogen concentration, serum concentration of fibrin and fibrinogen-related antigens (FRA), and plasma antithrombin III (AT III) activity were determined for all dogs. Results from affected dogs were compared with those of control dogs. In some affected dogs, postmortem tissue specimens were examined for evidence of microvascular thrombosis. A diagnosis of DIC was made by fulfilling at least 3 of the following criteria: 1) abnormal aPTT, PT, or TCT value, 2) low plasma fibrinogen concentration, 3) low plasma AT III activity, 4) high serum FRA concentration, or 5) low platelet count. To evaluate the severity of hemostatic dysfunction, 3 arbitrary categories (mild, moderate, and severe) were proposed. RESULTS: A diagnostic strategy based on moderate hemostatic dysfunction identified DIC in 16 of 59 (27.1%) affected dogs. The AT III activity was < 70% in 15 of 16 dogs with DIC. Microvascular thrombosis was observed in tissue specimens from 7 of 8 affected dogs. Serum FRA and plasma fibrinogen concentrations did not contribute in establishing a diagnosis of DIC. CONCLUSIONS AND CLINICAL RELEVANCE: A diagnosis of DIC can be made when hemostatic dysfunction is moderate in dogs with clinical signs of diseases associated with DIC.     

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 time (TT) were taken at 8 hourly intervals during the treatment period and at all of the Control Period Hours. Mean plasma heparin concentrations increased significantly (P less than 0.01) from 2 h after the first to 32 h after the last (seventh) injection. Mean values corresponding to the desired range of heparin in plasma (0.05 to 0.20 iu/ml) were achieved at 21 h after initiation of heparin treatment and were maintained during the following 81 h. Great individual variations in the sensitivity to heparin among horses, cumulation of heparin in plasma with prolonged administration and a marked circadian periodicity in the disposition of heparin affected actually measured plasma heparin values. A chronodiagram revealed peak values around 1300 h, trough values around 0500 h. The peak-trough difference amounted to about 50 per cent. Increasing plasma heparin concentrations were associated with erratic prolongations of mean APTT and TT values. The AT III curve was not affected significantly.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in the blood coagulation profile after ovariohysterectomy in female dogs

This study investigated changes in the coagulation profile of 10 healthy female dogs subjected to ovariohysterectomy. Blood samples were collected three times--before, directly after and 24 h after surgery. Plasma samples were analyzed to determine thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen content, D-dimer content and antithrombin (AT) III activity. The results revealed post-operative haemostatic system disorders related to prolonged APTT, higher fibrinogen and D-dimer concentrations and lower levels of AT III activity.     

Antithrombin III activity in horses with large colon torsion

A chromogenic peptide substrate assay was used to determine serially plasma antithrombin III (AT III) activity in 4 groups of horses. Group I consisted of healthy, mature horses in which AT III activity was determined twice daily for 7 consecutive days. Groups 2 and 3 contained healthy horses in which AT III activity was monitored for 7 days after controlled, but varying, conditions of general anesthesia and surgery (median celiotomy). Group 4 was made up of patients with a presurgical diagnosis of colonic torsion. In healthy awake horses (group I), there was no difference in AT III values over time. Postoperative AT III activity in the halothane-anesthetized horses (group 2) and in the sham-operated horses (group 3) was not significantly (P = 0.05) different from base-line values at any time. A significant decrease (P = 0.05) in AT III activity was observed on postoperative days 1 through 3 in the group of horses with large colon torsion, but returned to preoperative values by day 4 after surgery in the horses that survived. In those horses that did not survive, AT III activity remained below base-line values for the duration of observation. Seemingly, plasma AT III activity in horses was not significantly affected by halothane anesthesia or surgery. Serial evaluation of AT III activity may be useful for predicting survival in horses with large colon torsion.     

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 significantly abnormal: decreased antithrombin III (AT III) values, increased level of fibrin degradation products (FDP), thrombocytopenia, prolonged activated partial thromboplastin time, and prolonged prothrombin time. The most consistent hemostatic abnormalities were decreased AT III activity, increased FDP titers, and thrombocytopenia. Clotting times were more variable and did not always correlate with the presence of excessive hemorrhage. Excessive hemorrhage was present during surgery in seven horses and occurred within 1 to 12 hours after surgery in nine other horses. In addition to treatment of the primary disease, 19 horses received treatment for DIC consisting of heparin and/or plasma or fresh whole blood transfusions. Heparin alone was used in 12 horses. Heparin, in addition to fresh whole blood transfusions or fresh plasma, was administered to four horses. Three horses were treated with plasma alone. Four other horses were not treated specifically for the DIC. Eight horses (34%) survived the acute coagulopathy. Although a greater proportion of the surviving horses received heparin therapy (87.5%; 7/8) than did those that died (60%; 9/15), the difference was not statistically significant (P = 0.345).(ABSTRACT TRUNCATED AT 250 WORDS)     

Early phase components of the kallikrein kinin system in hemorrhagic ascitic fluid and plasma in the rat with induced acute pancreatitis

Acute hemorrhagic pancreatitis (AHP) was induced in 43 anesthetized rats by retrograde injection of sodium taurodeoxycholic acid into the common pancreatic biliary duct. At postinjection hours 1, 3, 6, 12, and 18, samples of plasma and hemorrhagic ascitic fluid (HAF) were obtained from rats in which AHP was induced and from rats that were sham operated. Early phase components of the kallikrein kinin system, including kallikrein-like (KK) activity and prekallikrein (PKK) and kallikrein inhibitor (KKI) concentrations, were measured in plasma and HAF samples. In the rats with induced AHP, PKK concentrations were decreased significantly in 18-hour plasma samples (P less than 0.05) and in all HAF samples (P less than 0.001) from 1 to 18 hours after induction of AHP. The KK activity was significantly increased (P less than 0.001) in the 6- and 12-hour plasma samples. In the 1-hour HAF samples, KK activity was increased greater than 10 times over that in the plasma pool of rats and remained increased for 18 hours. The KKI concentrations were markedly decreased in all HAF samples. In the sham-operated group, no significant change was observed. Histopathologic changes included edema, extensive hemorrhage, focal necrosis of many acinar cells around the head of the pancreas, slight inflammatory cell infiltration, vascular thrombosis, and partial lysis of pancreatic ducts. The extent of the changes of PKK, KK, and KKI values in HAF was greater than the extent of those in plasma. Increasing KK activity in plasma and HAF is indicative of bradykinin generation and the participation of this system in local and systemic pathologic change.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of the antibacterial activity of honey from different provenance against bacteria usually isolated from skin wounds

The antibacterial activity of honey samples provided by apiarists and honey packers was tested against microorganisms usually isolated from skin wounds. The antibacterial activity was tested using the well-agar diffusion assay. The honey samples were tested without dilution, and at 75, 50, 30, and 10% (w/v) dilution. Most of the undiluted honey samples inhibited the growth of Staphylococcus aureus and Staphylococcus epidermidis. Some honey samples provided by apiarists also inhibited the growth of S. aureus even at 50% dilution. Undiluted honey samples also inhibited the growth of Staphylococcus uberis, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae, although to a lesser extent. No inhibition of Micrococcus luteus and Enterococcus faecalis growth was detected. The diameters of the inhibition zones generated by honey samples provided by apiarists were larger than those generated by honey samples provided by honey packers. This observation may be explained by considering the provenance of the honey samples.     

Hemostatic Disorders in Feline Immunodeficiency Virus-Seropositive Cats

The hemostatic function of 40 feline immunodeficiency virus (FlV) seropositive and 8 FIV and feline leukemia virus (FeLV) seropositive cats was evaluated and compared with reference values from 30 clinically healthy cats. The FIVpositive cats were divided into 3 groups: group I included asymptomatic carriers; group II comprised sick FIV-infected cats with illnesses not likely to influence the hemostatic system; and group III included FIV-positive cats with diseases potentially associated with coagulopathies. Platelet counts in FIV/FeLV-infected cats were significantly lower than in healthy cats (P < .003), whereas the differences in the 3 groups of FIV-positive cats were variable (group I, P= .009; II, P= .05; III, P= .09). Thrombocytopenia (< 145,000 platelets/μL) was present in 4 FIV-positive and 3 FIV/FeLV-positive cats. Platelet aggregation induced by collagen (0.5 and 0.25 μg/mL), adenosine diphosphate (ADP) (1 and 0.6 μmol/L), and thrombin (0.4 and 0.25 IU/mL) was not significantly different from that of healthy cats. The plasma coagulation system was evaluated by measuring one-stage prothrombin time (OSPT), activated partial thromboplastin time (APTT), thrombin time, fibrinogen concentration, coagulation factor assays, fibrinogen and fibrin degradation products (FDP), and plasma exchange test. The OSPT was similar in FlV-seropositive cats and in the healthy control group. Cats with FIV infection, however, had markedly shorter clotting times than healthy cats when using a modified test system (P < .05). In all groups of FIV-infected cats and in those with FIV/FeLV infection, APTT measured with 2 different commercially available tests, and a modified plasma assay was markedly prolonged compared with healthy cats (APTT1 and 2:3 modification: P < .01; APTT2: P < .05 except group III). In 22 of 40 cats with FIV and in 5 of 8 cats with FIV/FeLV infection, plasma samples were beyond the reference range. The thrombin time was also significantly prolonged in cats with FIV and FIV/FeLV infection (P < .01); values in 17 of 40 FIV-positive cats were above reference range. The mean fibrinogen concentration of cats with FIV and FIV/FeLV infection was higher than in the healthy control group (P < .001). Factor VIII activity of 4 cats with FIV infection was 1.5 times higher than that of healthy cats. Factor XII activity of 3 cats from a group of 20 cats with prolonged APTT was between 20% and 35%. Factor IX and XI activities ranged between 70% and 120%. The markedly prolonged APTT in 2 FIV-positive cats could be shortened considerably in a plasma exchange test using 20% feline pooled plasma. The alterations in the coagulogram of FIV-seropositive cats were not related to a clinical stage or concurrent diseases. A definite explanation of the distinct disorder within the intrinsic plasma coagulation system in FIV-infected cats was not found.     

Sensitivity of commercial prothrombin time reagents to detect coagulation factor deficiencies in equine plasma

The sensitivity of commercial prothrombin time (PT) tests was assessed based on a dilution series of equine pooled plasma (EPP) (experiment 1) and on 40 equine plasma samples with reduced activity of coagulation factors II, V, VII and X (experiment 2). Two different PT reagents (reagent 1, human placental thromboplastin; reagent 2, recombinant human tissue factor) were used according to the manufacturers' instructions (standard test, PT([ST])) and compared to a modified test procedure (modified test, PT([MT])) using sample dilution and fibrinogen addition. In all samples, sensitivity was lower (P<0.01) when using PT([ST]) with reagent 2 (0.20) than when using either PT([ST]) with reagent 1 (0.65) or PT([MT]) with both reagents (reagent 1, 0.60-0.75, reagent 2, 0.58-0.70, depending on sample dilution). The highest sensitivity was found for PT([MT]) when using a 1:20 sample dilution. In those samples in which at least one coagulation factor activity was decreased (by 20%; n=18), the sensitivity of PT([ST]) with reagent 2 (0.33) was found to be inadequate, in contrast to all other test procedures (0.83-0.94). This low sensitivity corresponded to shorter time intervals between different coagulation activity levels prepared by EPP dilution. The results indicate that adequate sensitivity of PT measurements in equine plasma can be achieved using a standard test procedure as long as a suitable reagent is used.     

Alteration of haemostatic parameters in uncomplicated canine babesiosis

Babesiosis is a tick-borne zoonotic disease caused by haemoprotozoan parasites. The aim of this study were to assess markers of coagulation pathways in 25 dogs with naturally occurring babesiosis caused by B. canis, compared to 10 healthy controls. Protein C (PC) and antithrombin III (AT III) activity were assessed using a chromogenic substrate test, while levels of thrombin-antithrombin (TAT) complexes, activated protein C (APC) and endothelial protein C receptor were assessed using canine-specific ELISA. AT III activity was decreased as a result of a negative acute phase response, degradation by elastase, reduced availability of glycosaminoglycans, and, most importantly, consumption as a consequence of thrombin formation. Procoagulant state and haemostatic shift towards thrombin formation are also demonstrated by elevated TAT levels. Regarding PC pathway only significant difference was found for APC. Taken together, haemostatic alterations in uncomplicated babesiosis represent a procoagulant state that is mostly reversed during treatment.     

The effect of hemolysis on plasma antithrombin activity as determined by a chromogenic method

BACKGROUND: The concentration of free hemoglobin (Hgb) in plasma can markedly affect the outcome of laboratory tests by interfering with the spectrophotometric absorbance of biochemical tests read at wavelengths within the absorbance range of Hgb (400-440 nm). Little is known about the effects of hemoglobinemia on antithrombin (AT) activity in human plasma samples, and we are unaware of data for canine plasma samples. OBJECTIVES: The objective of this study was to determine the degree of interference by Hgb on plasma AT activity and to determine if the interference is proportional to the concentration of plasma Hgb. METHODS: Two pools of test plasma, designated AT100 and AT70, were prepared. Hemolysate was prepared by washing and freeze-thawing packed red cells in a small volume of saline, followed by collection of the filtrate. Solutions of decreasing Hgb concentration were prepared and added to the test plasma pools to create a series of samples with final calculated and measured Hgb concentrations of 0, 0.5, 1.5, 2.5, 3.5, 4.5, and 5.5 g/L. AT activity, expressed as a percentage of normal human plasma, was determined using a functional chromogenic assay. RESULTS: Increasing concentrations of Hgb resulted in a linear decrease in AT activity. Using linear regression analysis on the 70% and 100% plasma pools, the slopes for samples containing <1.5 g Hgb/L were not significantly different from zero. Slopes for samples containing Hgb concentrations >or=1.5 g/L were significantly (P > .0001) different from zero for both plasma pools, indicating interference with the assay. CONCLUSIONS: The results of this study suggest it may be possible, using a conversion equation, to accurately determine AT activity in hemolyzed samples, facilitating evaluation of coagulation status in patients with intravascular hemolysis.     

Changes in coagulation and markers of fibrinolysis in horses undergoing colic surgery

Activation of coagulation can be frequently found in horses with colic. However, it has also been demonstrated as a sequela of surgical trauma alone in humans. The purpose of the present study was to determine changes in coagulation and fibrinolysis in horses that underwent colic surgery and to evaluate whether these changes were secondary to the colic or the surgery and wound healing. Thirty horses that underwent colic surgery with uncomplicated recovery were included. Ten horses with a Forssell's procedure served as control group with a standardized surgical trauma. Besides daily physical examinations during the observation period of 10 days, activated partial thromboplastin time (aPTT), prothrombin time and thrombin time as well as fibrin monomer (FM), D-Dimer (DD) and antithrombin (AT) III were determined. Compared with the control group the aPTT was the only standard coagulation test that was significantly prolonged before and after the event of colic surgery. After surgery, hyperfibrinogenaemia occurred in all groups. In colic groups FM and DD concentrations were within reference range at admission,and were significantly greater than in control horses after surgery. AT III activity decreased after colic surgery, but did not change in the control group. It was concluded that an activated coagulation state after colic surgery has to be expected, resulting not only from the colic disease, but also from the event of surgery.     

Clinical relevance of monocyte procoagulant activity in horses with colic

Endotoxin-activated monocytes express a thromboplastin-like procoagulant activity on the cell surface that may serve as a focal point for formation of microvascular thrombi. Because coagulopathy is a common sequela to endotoxemia in the equine species, we investigated the ability of monocytes, isolated from horses with colic, to express procoagulant activity. On the day of admission, and on the third and fifth day of hospitalization, monocytes were isolated from 30 adult horses with colic. A coagulation profile, including prothrombin time, activated partial thromboplastin time, thrombin time, and plasma fibrinogen and serum fibrin degradation products concentrations, was determined at each sample collection. The concentration of endotoxin in the plasma was quantitated at the time of admission. Ten clinically normal adult horses served as controls. The procoagulant activity of monocytes isolated from horses with colic was significantly (P less than 0.05) greater than that of the monocytes isolated from clinically normal horses. On the first and third day of hospitalization, the mean prothrombin time was significantly (P less than 0.05) longer in horses with colic, compared with clinically normal horses, and was the most common abnormality in the coagulation profile on the day of admission (25/30; 83%). Mean fibrin degradation products concentration was significantly (P less than 0.05) greater in horses with colic on the day of admission and was the second most common abnormality in the coagulation profile on day 1 (23/30; 77%). In horses with colic, the mean prothrombin and activated partial thromboplastin times were significantly (P less than 0.05) longer in horses that did not survive, compared with horses that survived.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of a chromogenic assay to measure the factor Xa inhibitory activity of unfractionated heparin in canine plasma

BACKGROUND: Unfractionated heparin (UFH) has a complex pharmacologic profile that necessitates patient monitoring to prevent inadequate anticoagulation or overdosage and hemorrhage. Factor Xa inhibitory assays (to measure anti-Xa activity) are used to adjust UFH dosage and define safe and effective regimens for specific thrombotic disorders in humans. OBJECTIVE: In this study, the accuracy, linearity, and clinical utility of a chromogenic assay were assessed for monitoring UFH anti-Xa activity in canine plasma samples. METHODS: A commercial assay (Rotachrom Heparin, Diagnostica Stago, Parsippany, NJ, USA) was used to measure anti-Xa activity in canine plasma samples spiked with different concentrations of UFH. Background absorbance and assay linearity were compared for canine and human plasmas. Percentage recovery of UFH anti-Xa activity and intra- and interassay imprecisions were investigated by multiple measurements of canine plasma to which known amounts of UFH were added. The spiked plasma samples also were used to determine the heparin sensitivity of an activated partial thromboplastin time (aPTT) test. RESULTS: Canine plasma samples were assayed at a higher dilution than were human plasma samples (3:8 versus 4:8) to eliminate higher background anti-Xa activity in canine plasma. Using this modification, the recovery of anti-Xa activity in canine plasma was linear (R2 > .9) at concentrations of 0 - 0.75 U/mL UFH. Intra- and interassay imprecisions for plasma samples containing 0.5 U/mL UFH were <10%, whereas samples containing 0.25 U/mL UFH had imprecisions of 13% and 24%, respectively. The anti-Xa activity range of 0.5 - 0.75 U/mL caused prolongation of aPTTs to 1.5 - 2.5 times the assay mean. CONCLUSION: Plasma anti-Xa activity of dogs treated with UFH can be accurately monitored using this commercially available chromogenic assay.     

One-stage prothrombin time, activated partial thromboplastin time, thrombin time, fibrin degradation product concentration, and antithrombin activity in healthy adult alpacas

Background: Alpacas are increasingly presented to veterinarians for evaluation and care. Reports of alpaca reference intervals for one‐stage prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), concentration of fibrin degradation products (FDP), and antithrombin (AT) activities are scarce or nonexistent. Objective: The aim of this study was to determine values for blood coagulation times (PT, aPTT, and TT), FDP concentrations, and AT activities in healthy adult alpacas. Methods: Of blood samples collected from 35 clinically healthy adult alpacas via jugular venipuncture and placed into sodium citrate and FDP tubes, 29 samples were assayable for coagulation testing. PT, aPTT, and TT were determined by physical (mechanical) clot detection; AT activity was determined using a thrombin‐specific chromogenic substrate end‐point assay; and FDP concentrations were determined by the slide agglutination method. Results: Median values and ranges (minimum–maximum) were determined for PT (8.7 seconds, 6.6–11.2 seconds), aPTT (17.3 seconds, 11.9–22.5 seconds), TT (10.2 seconds, 5.4–16.0 seconds), and AT activity (123.3%, 104.8–144.2%). The mean concentration of FDP was <8 μg/mL. Conclusion: These values for coagulation times, FDP concentration, and AT activity will provide a useful starting point in the diagnostic evaluation of ill adult alpacas.     

Hemostatic alterations in pigs fed sublethal doses of Sarcocystis miescheriana

Effects of non-lethal Sarcocystis miescheriana infections on the blood coagulation system were investigated. Nine pigs were inoculated orally with 2 X 10(5) sporocysts (Group A) and nine pigs (Group B) served as non-infected controls. Blood samples were taken from the vena jugularis externa every 2 or 3 days until 19 days post-infection (dpi). The following parameters were investigated: partial thromboplastin time (PTT), prothrombin time (PT), thrombin time (TT), thrombin coagulase time (TCT), fibrinogen (FIB), factor (F) VIII, F XI, F XII, antithrombin III (AT III), alpha 2 macroglobulin (alpha 2 MG), alpha 2 antiplasmin (alpha 2 AP), pre-kallikrein (PK), and the number of circulating thrombocytes. All infected pigs suffered from acute sarcocystiosis between 12 and 19 dpi. Clinical illness was most severe from 14 to 17 dpi. At this time, PTT and FIB increased, and TT and TCT decreased slightly. The activities of the clotting factors increased at 17 and 19 dpi. However, only F VIII activity was significantly higher in the infected pigs than in the controls at 17 and 19 dpi. PK was significantly lower in the infected pigs at 12, 14, and 17 dpi. Thrombocyte counts were reduced with the onset of the acute phase of illness and some pigs had marked thrombocytopenia. These results indicate low-grade disseminated intravascular coagulation (DIC) in the course of mild S. miescheriana infections in pigs.     

Stability of canine factor VIII: coagulant activity in vitro.

A pilot study was undertaken to assess the stability of canine factor VIII:coagulant (FVIII:C) activity over three days, under various storage conditions (plasma at 4, 20 and 37 degrees C, whole blood at 4 and 20 degrees C). Blood collected from normal and hemophiliac dogs was used. Both plasma and whole blood samples appeared to be stable for up to 48 h at 4 and 20 degrees C. A subsequent study evaluated FVIII:C stability at 4 and 20 degrees C when stored as whole blood only. Samples were tested at 0, 24 and 48 h after collection. At 4 degree C there was a significant decline at 24 h (p less than 0.05), from 110% to 97% (mean values). Although the mean value was further decreased at 48 h (89%) this was not significant (p greater than 0.05). No significant change in FVIII:C activity was observed in whole blood stored at 20 degrees C for 24 or 48 h (110% and 107% respectively). These results suggest that canine whole blood samples collected into sodium citrate stored at 20 degrees C are adequate for routine FVIII:C assay for up to 48 h after collection.     

Serologic prevalence of toxoplasmosis in cattle, sheep, goats, pigs, bison, and elk in Montana

Serum samples from 2,539 cattle, 649 sheep, 123 goats, 413 pigs, 93 bison, and 56 elk from Montana were examined for antibody to Toxoplasma gondii in the Sabin-Feldman dye test or the modified agglutination test (MAT). Cattle, bison, and elk serum samples were treated with 0.2 M-mercaptoethanol before examination in MAT. In the dye test, 13.2% of sheep, 5.0% of pigs, and 22.7% of goats had antibody at a dilution of greater than or equal to 1:16. In the MAT, 3.2% of cattle, 3.1% of bison, and none of the elk were positive at a dilution of greater than or equal to 1:128.     

Evaluation of a rapid method of determination of plasma fibrinogen in swine.

An evaluation was made of a rapid semiautomated method for determining fibrinogen level in swine plasma. This method, referred to as thrombin time method or fibrometer method, is based on the principle that when thrombin is added to suitably diluted plasma, the time of clotting is linearly related to the fibrinogen concentration. The linear regression model for the standard curve prepared using swine plasma had an r value of 0.998. A comparison between the fibrometer and the Grannis methods done on 189 swine plasma samples showed good correlation between these two mehtods (r value 0.847). It was concluded that although the fibrometer method may not be as precise as the Grannis method, it would still be acceptable for clinical use in swine.     

Evaluation of the effect of storage at -70 degrees C for six months on hemostatic function testing in dogs.

Freezing is a routine method of storage for plasma that is to be used in evaluating certain aspects of hemostatic function in many species. The purpose of this study was to evaluate the effect of storage at -70 degrees C for 6 mo on canine plasma samples. On fresh and frozen plasma from 12 clinically healthy dogs, prothrombin time, activated partial thromboplastin time, thrombin clotting time, fibrinogen determination, antithrombin III activity, fragment D and E assay, and protamine sulfate test were performed. Clinical agreement analysis was utilized to determine the effect of such storage on all assays. Individual differences detected between fresh and frozen samples were all within 2 standard deviations of the mean difference. With the exception of the activated partial thromboplastin time, storing canine plasma at -70 degrees C for 6 mo has no significant effect on hemostatic function, as assessed by these tests.