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Abstract

Objective—To describe the effects of lithium carbonate on thrombopoiesis in clinically normal dogs and in dogs treated with carboplatin.

Animals—18 young adult sexually intact female Beagles.

Procedures—Dogs were assigned to each of 3 treatment groups (6 dogs/group). Group 1 received 150 mg of lithium carbonate (14 to 16 mg/kg), PO, every 12 hours on days 1 through 21. Group 2 received carboplatin (300 mg/m2, IV) on day 0 and cephalexin (30 mg/kg, PO, q 12 h) on days 14 through 21. Group 3 received lithium, carboplatin, and cephalexin at the aforementioned doses and schedules. Plasma lithium and blood platelet concentrations were measured on days 0, 2, 4, 7, 9, 11, 14, 16, 18, and 21. Number of megakaryocytes in bone marrow specimens and the percentage of large unstained cells and CD34+ mononuclear cells in bone marrow aspirates were determined on days 0, 7, 14, and 21 by manual enumeration, automated hematologic analysis, and flow cytometric immunophenotyping, respectively.

Results—Plasma lithium concentrations ranged from 0.12 to 2.41 mmol/L. All dogs given lithium achieved a concentration within the target interval of 0.5 to 1.5 mmol/L by days 4 to 7. Thrombopoiesis was increased in dogs receiving lithium alone. All dogs given carboplatin developed mild thrombocytopenia. There were no differences between group 2 and group 3 throughout the study.

Conclusions and Clinical Relevance—Lithium stimulated thrombopoiesis in clinically normal dogs. Lithium administration at the doses and schedules used, with concurrent administration of cephalexin, did not prevent thrombocytopenia induced by carboplatin.

Full access
in American Journal of Veterinary Research

SUMMARY

Objective

To determine whether in vitro viability and function, and microbiological sterility, of canine platelet concentrates (PC) could be retained during storage at 20 to 24 C (room temperature [RT]) for up to 7 days and cryopreservation for 6 months.

Animals

14 mature dogs.

Procedure

PC prepared by centrifugation of fresh blood were stored for 7 days at RT with continuous agitation. An aliquot of each was cryopreserved with 6% dimethyl sulfoxide at −74 C for 6 months. Fresh PC (day 0) were tested by microbial culture and measurement of platelet count, mean platelet volume, pH, glucose and lactate concentrations, lactate dehydrogenase activity, response to hypotonic stress, and aggregation. Tests were also performed on PC stored at RT on days 3, 5, and 7, and on the cryopreserved aliquots after thawing.

Results

After 7 days at RT, microbial growth was not evident, and decrease in platelet number was not significant. On the basis of pH and glucose and lactate concentrations, metabolic activity was maintained throughout RT storage. On the basis of mean platelet volume and lactate dehydrogenase activity, platelet swelling and membrane damage had occurred. Aggregatory responses decreased during RT storage, and platelets recovered poorly from hypotonic stress. After cryopreservation for 6 months, microbial growth was not evident, but platelet numbers were significantly decreased. Mean platelet volume and lactate dehydrogenase activity were significantly greater, compared with values for day-0 PC. Crypreserved platelets aggregated poorly and did not respond to hypotonic stress.

Conclusions

Platelet viability and microbiological sterility are retained in canine PC stored for 7 days at RT, but platelet function progressively decreases and day-7 platelets are substantially damaged. Crypreservation of PC results in considerable damage, compared with that of PC stored at RT.

Clinical Relevance

Similar to human PC, canine PC stored at RT for up to 5 days can be recommended for treatment. (Am J Vet Res 1997;58:1338–1347)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effects of enteral administration of doxycycline, amoxicillin, cephalexin, and enrofloxacin at therapeutic dosages for a typical duration on hemostatic variables in healthy dogs.

Animals—14 Beagles.

Procedure—Doxycycline (10 mg/kg, PO, q 12 h), amoxicillin (30 mg/kg, PO, q 12 h), cephalexin (30 mg/kg, PO, q 12 h), and enrofloxacin (20 mg/kg, PO, q 24 h) were administered in random order to 10 healthy dogs at standard therapeutic dosages for 7 days, with a 7-day washout period between subsequent antimicrobials. In addition, 4 Beagles served as control dogs. Variables were evaluated before and after antimicrobial administration; they included platelet count, Hct, 1-stage prothrombin time (PT), activated partial thromboplastin time (PTT), fibrinogen concentration, and platelet function. Platelet function was assessed via buccal mucosal bleeding time, aggregation, and a platelet-function analyzer.

Results—Administration of all antimicrobials caused a slight prolongation of 1-stage PT and activated PTT and slight decrease in fibrinogen concentration. Cephalexin caused a significant increase in 1-stage PT and activated PTT, amoxicillin caused a significant increase in activated PTT, and enrofloxacin caused a significant decrease in fibrinogen concentration. Platelet count or function did not differ significantly after administration of any antimicrobial.

Conclusions and Clinical Relevance—Oral administration of commonly used antimicrobials in healthy dogs resulted in minor secondary hemostatic abnormalities, with no change in platelet count or function. Although these changes were clinically irrelevant in healthy dogs, additional studies of the effects of antimicrobial administration on hemostasis in animals with underlying disease processes are warranted.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To describe the effects of prednisone and acetylsalicylic acid (ASA) on results of thromboelastography in healthy dogs.

Animals—16 male mixed-breed dogs.

Procedures—Dogs were randomly assigned to 3 treatment groups (4 dogs/group) that received prednisone (median dose, 2.07 mg/kg), ASA (median dose, 0.51 mg/kg), or both drugs, PO, every 24 hours from days 0 through 6. Another group received no treatment (control dogs; n = 4). Thromboelastography variables (reaction time, clotting time, α-angle, maximum amplitude [MA], global clot strength, coagulation index, and percentage of clot lysis at 60 minutes [CL60]) were evaluated in blood samples collected (prior to drug administration in treated dogs) on days 0 (baseline), 2, 4, and 6.

Results—Administration of ASA alone did not alter TEG variables. For treatment effect, mean global clot strength was increased in the prednisone and drug combination groups, compared with values for control dogs; MA was also increased in the prednisone and drug combination groups, compared with that of controls. For treatment-by-time effect, median CL60 was increased in the prednisone group on day 6, compared with baseline value in the same dogs and with median CL60 of the control group on day 6. Median CL60 was also increased in the drug combination group on day 6, compared with the baseline value and with that of the control group on day 6.

Conclusions and Clinical Relevance—Prednisone administered at approximately 2 mg/kg/d, PO, for 7 days with or without concurrently administered ASA increased clot strength and decreased clot lysis in healthy dogs.

Full access
in American Journal of Veterinary Research

Summary

A protocol was developed for preparation of platelet concentrates (pc) to support thrombocytopenic dogs. Four clinically normal dogs with platelet counts that ranged from 200 to 330 × 109 platelets/L were used as donors. One unit (450 ml) of blood was collected by venipuncture into a double blood bag. Whole blood (wb) was centrifuged for 4 minutes at 1,000 × g (braking time = 2 minutes, 30 seconds) to prepare platelet-rich plasma (prp). The prp was expressed into the satellite bag and was centrifuged for 10 minutes at 2,000 × g (braking time = 2 minutes, 36 seconds). The platelet-poor plasma was expressed, leaving 40 to 70 ml of plasma and the pelleted platelets in the satellite bag. The resulting pc was left undisturbed for 60 minutes to promote disaggregation, and the platelets were then resuspended by gentle manual agitation.

Forty-eight pc were prepared. Mean (± sd) platelet yield from wb to prp was 78 (±13)% (range, 35 to 97%); yield from prp to pc was 94 (± 6)% (range, 75 to 100%); and overall yield (pc from wb) was 74(± 13)% (range, 36 to 91%). Mean pc platelet count was 8.0 (± 3.0) × 1010 platelets/pc (range, 2.3 to 13.4 × 1010 platelets/pc). The wbc content was 0.1 to 2.3 × 109 platelets/pc, representing 3 to 74% of wbc in the wb. Hematocrit was 0.1 to 26.2%. Results of bacterial and fungal culturing were negative.

The pc were irradiated (18 Gy) and transfused to 5 cross-matched dogs undergoing bone marrow transplantation that developed profound thrombocytopenia of up to 8 weeks’ duration. Transfusions were given over 5 to 15 minutes, using a latex-free transfusion set. Platelet count in recipients was monitored to confirm reduction in the degree of thrombocytopenia. Mean actual 24-hour post-pc transfusion platelet count was significantly (P < 0.0001) higher than mean expected 24-hour platelet count without pc transfusion. Recipients were closely observed for hemorrhage, which did not occur. Prevalence of transfusion reactions was 17%; signs were fever (5/46), urticaria (1/46), vomiting (1/46), and anaphylaxis (1/46).

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To compare bronchoalveolar lavage (BAL) accomplished by use of a bronchoscopic (B-BAL) and a nonbronchoscopic (NB-BAL) technique in healthy cats.

ANIMALS 12 healthy cats.

PROCEDURES Two BALs were performed in a randomized order 2 weeks apart in each cat. Cats were anesthetized, and a 2.9-mm fiberoptic bronchoscope (B-BAL) or 8F red rubber catheter (NB-BAL) was wedged in a bronchus. Two 5-mL aliquots of saline (0.9% NaCl) solution were infused into the left and right caudal lung fields and aspirated manually with a 20-mL syringe. Proportion of BAL fluid (BALF) retrieved, depth of wedging, and anesthetic complications were recorded. Total nucleated cell count, differential cell count, and semiquantitative scores of cytologic slide quality were determined for all BALF samples. Results were compared with ANOVAs and Wilcoxon signed rank tests.

RESULTS Proportion of retrieved BALF and depth of wedging were significantly greater for B-BAL than NB-BAL. Differential cell counts and cytologic slide quality did not differ significantly between techniques. Complications included transient hemoglobin desaturation (24/24 [100%] BALs) and prolonged anesthetic recovery time (4/24 [17%] BALs). Anesthetic recovery scores did not differ significantly between techniques.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that NB-BAL was noninferior to B-BAL with regard to ease of performance, anesthetic variables, and cytologic slide quality for cats without clinical respiratory tract disease.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare the diagnostic quality of bronchoalveolar lavage (BAL) fluid acquired from healthy dogs by manual aspiration via polyethylene tubing (MAPT) and via suction pump aspiration (SPA) with a suction trap connection.

Animals—12 healthy adult Beagles.

Procedures—BAL was performed with bronchoscopic guidance in anesthetized dogs. The MAPT was performed with a 35-mL syringe attached to polyethylene tubing wedged in a bronchus via the bronchoscope's biopsy channel. The SPA was performed with 5 kPa of negative pressure applied to the bronchoscope's suction valve via a suction trap. The MAPT and SPA techniques were performed in randomized order on opposite caudal lung lobes of each dog. Two 1 mL/kg lavages were performed per site. Samples of BAL fluid were analyzed on the basis of a semiquantitative quality scale, percentage of retrieved fluid, and total nucleated and differential cell counts. Results were compared with Wilcoxon signed rank tests.

Results—Percentage of BAL fluid retrieved (median difference, 16.2%), surfactant score (median difference, 1), and neutrophil count (median difference, 74 cells/μL) were significantly higher for SPA than for MAPT. A higher BAL fluid epithelial cell score was obtained via MAPT, compared with that for samples obtained via SPA (median difference, 1).

Conclusions and Clinical Relevance—Results indicated that in healthy dogs, SPA provided a higher percentage of BAL fluid retrieval than did MAPT. The SPA technique may improve the rate of diagnostic success for BAL in dogs, compared with that for MAPT. Further evaluation of these aspiration techniques in dogs with respiratory tract disease is required.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare bronchoalveolar lavage (BAL) fluid obtained by manual aspiration (MA) with a handheld syringe with that obtained by suction pump aspiration (SPA) in healthy dogs.

Animals—13 adult Beagles.

Procedures—Each dog was anesthetized and bronchoscopic BAL was performed. The MA technique was accomplished with a 35-mL syringe attached to the bronchoscope biopsy channel. The SPA technique was achieved with negative pressure (5 kPa) applied to the bronchoscope suction valve with a disposable suction trap. Both aspiration techniques were performed in each dog in randomized order on opposite caudal lung lobes. Two 1 mL/kg aliquots of warm saline (0.9% NaCl) solution were infused per site. For each BAL fluid sample, the percentage of retrieved fluid was calculated, the total nucleated cell count (TNCC) and differential cell count were determined, and semiquantitative assessment of slide quality was performed. Comparisons were made between MA and SPA techniques for each outcome.

Results—1 dog was removed from the study because of illness. The mean percentage of fluid retrieved (mean difference, 23%) and median TNCC (median distribution of differences, 100 cells/μL) for samples obtained by SPA were significantly greater than those for samples obtained by MA.

Conclusions and Clinical Relevance—In healthy dogs, BAL by SPA resulted in a significantly higher percentage of fluid retrieval and samples with a higher TNCC than did MA. Further evaluation of aspiration techniques in dogs with respiratory tract disease is required to assess whether SPA improves the diagnostic yield of BAL samples.

Full access
in American Journal of Veterinary Research

Abstract

Case Description—A 1.5-year-old spayed female domestic shorthair cat was admitted for hind limb locomotor difficulties and signs of pain along the lumbar portion of the vertebral column. At the time of referral, the cat was paraparetic with deficits in the spinal reflexes of the hind limbs. Neuroanatomic localization was at the L6-S2 spinal cord segments, corresponding approximately to the region of the L4-L6 vertebral bodies.

Clinical Findings—Radiography revealed a mixed osteolytic-proliferative lesion within the body of L5 involving the cranial end plate, as well as punctate radiolucencies in the distal portion of the femur. Magnetic resonance imaging revealed an intramedullary spinal cord lesion along with extensive meningeal and nerve root lesions in the area of the L4-L6 vertebral bodies. Cytologic analysis of a bone marrow aspirate from the right trochanteric fossa revealed a substantial plasma cell infiltrate. Analysis of CSF revealed a high protein concentration and morphologically abnormal plasma cells. Urine, but not serum, protein electrophoresis revealed a sharp γ-globulin peak consistent with a monoclonal band of Bence-Jones proteins. The diagnosis was multiple myeloma.

Treatment and Outcome—The cat was treated with melphalan and prednisolone. A rapid clinical response was reported, and by week 3 after diagnosis, the cat's locomotion and behavior had normalized. However, by month 4, multifocal neurologic deficits were evident. The cat was euthanized at 9 months because of tetraparesis and substantial weight loss.

Clinical Relevance—To our knowledge, this is the first report of myeloma in a cat that had electrophoretically detectable light chain proteinuria but lacked a detectable serum monoclonal gammopathy.

Full access
in Journal of the American Veterinary Medical Association

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 concena 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. (J Am Vet Med Assoc 1999;215:798–804).

Free access
in Journal of the American Veterinary Medical Association