Outcomes of 434 dogs with non-steroidal anti-inflammatory drug toxicosis treated with fluid therapy, lipid emulsion, or therapeutic plasma exchange

BACKGROUND

Traditional management of non-steroidal anti-inflammatory drug (NSAID) intoxication includes gastrointestinal decontamination, intravenous administration of fluids (IVF), and gastroprotection. Intravenous administration of lipid emulsion (ILE) and therapeutic plasma exchange (TPE) are popular novel therapeutic strategies.

HYPOTHESIS

Compare outcomes of dogs treated with IVF, ILE, and TPE for NSAID intoxications and evaluate outcome predictors for drug subgroups.

ANIMALS

Four hundred thirty-four dogs with NSAID intoxications (2015-2020).

METHODS

Multicenter retrospective study of ibuprofen, carprofen, and naproxen intoxication. An ordinal outcome was defined as mild gastrointestinal, moderate kidney, or signs of severe central nervous system disease.

RESULTS

Signs of neurological disease were overrepresented and acute kidney injury underrepresented in the TPE group among dogs exposed to kidney- or CNS-toxic doses (P = .05), though all TPE dogs with signs of neurological disease had evidence of neurotoxicity at presentation. Dogs treated with IVF had a higher maximal creatinine concentration (median, 1.1 mg/dL; range, 0.4-8.44 mg/dL) compared with IVF + ILE (median, 0.9 mg/dL; range, 0.4-6.2 mg/dL; P = .01). Increased maximum time to presentation (P < .001), higher baseline creatinine (P < .001) and PCV (P = .007), and absence of induced emesis (P < .001) were associated with greater clinical severity. Ibuprofen toxicosis was associated with more severe clinical signs compared with carprofen (P = .03). Overall survival rate was 99%.

CONCLUSIONS AND CLINICAL IMPORTANCE

NSAID toxicosis generally carries an excellent prognosis in dogs. Despite similar outcomes of lower incidence of AKI in the TPE group, and slightly lower maximal creatinine concentration in dogs treated with ILE vs IVF alone, ILE and TPE should be considered in the management of severe NSAID toxicosis.

Outcomes of nonsteroidal anti-inflammatory drug toxicosis treated with therapeutic plasma exchange in 62 dogs

BACKGROUND

Therapeutic plasma exchange (TPE) is gaining popularity for the management of nonsteroidal anti-inflammatory drug (NSAID) overdose in dogs.

HYPOTHESIS/OBJECTIVES

Describe a population of dogs treated with TPE for NSAID overdose.

ANIMALS

Sixty-two dogs with NSAID overdose treated with TPE.

METHODS

Multicenter retrospective study of dogs treated with TPE for ibuprofen, carprofen, or naproxen overdose.

RESULTS

The median dose of ibuprofen, carprofen or naproxen ingested was 533 mg/kg (range, 36-4857 mg/kg), 217 mg/kg (range, 88-625 mg/kg) and 138 mg/kg (range, 26-3000 mg/kg), respectively. Based on previously established toxic ranges for each NSAID, 2 (3.2%), 14 (22.6%), and 46 (74.2%) dogs ingested a gastrointestinal, renal, and neurological toxic dose, respectively. The median time between ingestion and presentation was 4 hours (range, 1-20 hours). The median number of plasma volumes processed was 1.6 (range, 0.4-2.2). The median TPE session duration was 2 hours (range, 1-4.5 hours). Circuit clotting developed during 8 (12.9%) sessions. Patient adverse events reported during 21 (33.8%) sessions consisted of urticaria (12.9%), asymptomatic hypocalcemia (9.6%), and hypotension (9.6%). The median duration of hospitalization was 2.25 days (range, 1-11 days). Sixty-one (98.4%) dogs survived to discharge, and none were rehospitalized. Thirty-one (91.1%) of the 34 dogs with at least 1 follow-up visit were not azotemic at the time of reevaluation.

CONCLUSIONS AND CLINICAL IMPORTANCE

This population of dogs managed with TPE had excellent outcomes, even in cases of high NSAID dose ingestion. When TPE is available and the time frame is appropriate, this extracorporeal modality should be considered for the management of NSAID overdose.

Use of therapeutic plasma exchange to treat nonsteroidal anti-inflammatory drug overdose in dogs

Background

Therapeutic plasma exchange (TPE) may be an effective technique for treatment of accidental nonsteroidal anti‐inflammatory drug (NSAID) overdose, but information regarding the use of this technique in veterinary medicine is currently limited.

Objectives

To evaluate the overall outcome for dogs with NSAID overdose treated with TPE and to determine if any presenting factors can predict or influence overall outcome. Secondary objectives included investigating TPE complications as well as the utility of other adjunctive treatments.

Animals

Eleven client‐owned dogs presented for NSAID overdose that received TPE. All patients also received additional supportive treatment including IV lipid infusion.

Methods

Retrospective review of medical records.

Results

Eleven cases were included in the study. Of these, the NSAID ingested was ibuprofen in 6 (54.5%), naproxen in 4 (36.4%), and deracoxib in 1 (9.1%). All dogs survived to discharge with 3 (27.3%) developing acute kidney injury during hospitalization. A larger initial dose of NSAID ingested was associated with a higher maximum serum creatinine concentration during hospitalization (P = .04) and larger change in serum creatinine concentration from baseline (P = .02). Six dogs (54.5%) developed complications associated with TPE. The use of other treatments did not affect the overall outcome.

Conclusions and Clinical Importance

We identified TPE as an effective treatment for NSAID overdose with good outcomes despite high doses of NSAID ingestion in dogs treated with a single TPE treatment. Complications were common but did not affect the final outcome. Therapeutic plasma exchange should be considered in patients presenting for high‐dose NSAID ingestion.

Prevalence of Anaplasma phagocytophilum infection in feral cats in Massachusetts

Objectives

The primary objective of this study was to determine the prevalence of Anaplasma phagocytophilum infection and exposure in adult feral cats in Massachusetts, an endemic area for A phagocytophilum and its tick vector Ixodes scapularis. The secondary objective was to determine if there were correlations between A phagocytophilum infection and the presence of anemia and thrombocytopenia.

Methods

Blood samples were collected between June and December 2015 from 175 apparently healthy adult feral cats that were presented to trap and release spay/neuter centers in Massachusetts. Complete blood count, blood smear evaluation, SNAP 4Dx Plus test (IDEXX) and A phagocytophilum PCR were performed on all samples to document acute infection (PCR-positive and/or inclusions observed on blood smear) and exposure to A phagocytophilum (SNAP 4Dx Plus-positive for A phagocytophilum antibodies).

Results

The prevalence of exposure to A phagocytophilum in feral cats in Massachusetts was 9.7%, whereas the prevalence of acute infection was 6.9%. All blood smears were negative for Anaplasma species inclusions; therefore, acute infection was defined as testing positive on PCR analysis. No statistically significant correlations were identified for cats that were positive for A phagocytophilum on PCR analysis or SNAP 4Dx Plus test and the presence of anemia or thrombocytopenia.

Conclusions and relevance

The prevalence of A phagocytophilum exposure in feral cats approaches 10% and is higher than the previously reported national average prevalence of 4.3% in the USA. A phagocytophilum infection may be an emerging infectious disease in cats. Further research is needed to determine the prevalence of clinical illness associated with A phagocytophilum infection in cats living in endemic areas.

Global cerebral ischemia with subsequent respiratory arrest in a cat after repeated use of a spring-loaded mouth gag

Case summary

A 10-year-old neutered male domestic shorthair cat was evaluated because of signs of stertorous breathing and reverse sneezing of 8 months' duration. A CT scan performed 1 week before evaluation indicated nasopharyngeal stenosis or collapse. Increased respiratory effort, stertorous breathing, coughing, reverse sneezing, bilateral black ocular discharge and mucoid left nasal discharge were noted. Rhinoscopy suggested possible nasopharyngeal stenosis. Balloon dilation was attempted but unsuccessful. Ventral rhinotomy was performed the following day using a spring-loaded mouth gag to access the surgical site. After rhinotomy, the patient had neurologic signs attributed to global cerebral ischemia that progressed to respiratory arrest, subsequently resulting in euthanasia.

Relevance and novel information

While ischemic brain injury has been associated with the use of a spring-loaded mouth gag in cats, to our knowledge this is the first reported instance where use resulted in respiratory arrest culminating in euthanasia.

The Use of Darbepoetin to Stimulate Erythropoiesis in the Treatment of Anemia of Chronic Kidney Disease in Dogs

Background

Darbepoetin alfa (darbepoetin) is an erythropoiesis‐stimulating agent used for the treatment of anemia secondary to chronic kidney disease (CKD) in dogs, but reports describing response are lacking.

Hypothesis/Objectives

To evaluate the effectiveness of darbepoetin in dogs with anemia secondary to CKD, dosing protocols, and adverse events.

Animals

Thirty‐three client‐owned dogs with naturally occurring CKD, including 26 with comorbidities.

Methods

Multi‐institutional retrospective study.

Results

The median starting dosage and highest dosage of darbepoetin administered were 0.5 and 0.8 μg/kg SC once weekly, respectively. Response to treatment was defined as achieving a packed cell volume (PCV) ≥30% or an increase in PCV ≥10%. Twenty‐eight of 33 dogs (85%) achieved a PCV ≥30% and 22 of 33 (67%) dogs achieved an increase in PCV ≥10%. Median time to achieve a PCV ≥30% was 29 days. A higher starting dosage was associated with achieving an increase in PCV ≥10% (P = .01). No dog sustained a response at a dosing interval >q21d. Potential adverse events included increased blood pressure requiring treatment (n = 12), seizures (n = 5), vomiting (n = 3), diarrhea (n = 3), and possible pure red cell aplasia (PRCA) (n = 2).

Conclusions and Clinical Importance

Darbepoetin, when combined with treatment of comorbidities, is an effective treatment for anemia secondary to CKD in dogs. A dosing interval >q21d was ineffective at maintaining a response to treatment. PRCA was a possible adverse event in 2 of 33 dogs (6%).

The pharmacokinetics of intravenous fenoldopam in healthy, awake cats

Fenoldopam is a selective dopamine-1 receptor agonist that improves diuresis by increasing renal blood flow and perfusion and causing peripheral vasodilation. Fenoldopam has been shown to induce diuresis and be well-tolerated in healthy cats. It is used clinically in cats with oliguric kidney injury at doses extrapolated from human medicine and canine studies. The pharmacokinetics in healthy beagle dogs has been reported; however, pharmacokinetic data in cats are lacking. The goal of this study was to determine pharmacokinetic data for healthy, awake cats receiving an infusion of fenoldopam. Six healthy, awake, client-owned cats aged 2-6 years old received a 120-min constant rate infusion of fenoldopam at 0.8 μg/kg/min followed by a 20-min washout period. Ascorbate stabilized plasma samples were collected during and after the infusion for the measurement of fenoldopam concentration by HPLC with mass spectrometry detection. This study showed that the geometric mean of the volume of distribution, clearance, and half-life (198 mL/kg, 46 mL/kg/min, and 3.0 mins) is similar to pharmacokinetic parameters for humans. No adverse events were noted. Fenoldopam at a constant rate infusion of 0.8 μg/kg per min was well tolerated in healthy cats. Based on the results, further evaluation of fenoldopam in cats with kidney disease is recommended.

Survey of dietary and medication practices of owners of cats with chronic kidney disease

The objective of this study was to describe the dietary and medication patterns of cats with chronic kidney disease (CKD). In this prospective, cross-sectional descriptive study, owners of cats with CKD were asked to complete a web-based survey. The study was advertised on CKD-, pet-, veterinary- and breed-associated websites and list serves. Owners of 1089 cats with CKD participated in the study. The mean reported age of the cats with CKD was 13.7 ± 4.2 years. Forty percent (430/1089) of cats had concurrent diseases, with hyperthyroidism, heart disease and inflammatory bowel disease being the most common. Veterinarian recommendation was the most common reason reported (684/1032; 66%) for diet selection, and 51% (556/1089) of owners fed a veterinary therapeutic diet formulated for kidney disease as some component of the diet. Many owners (466/1079; 43%) reported that their cats had an abnormal appetite; of these owners, 52% responded that their cats had a poor appetite or required coaxing to eat 5–7 days per week. Forty-seven percent and 51% of cats were receiving subcutaneous fluids and oral medications, respectively; however, most cats (811/1036; 78%) were not receiving phosphorus-binding medications. Fifty-six percent and 38% of cats received commercial cat treats and dietary supplements, respectively. Anorexia or hyporexia is a common problem in cats with CKD and may lead to cats being fed suboptimal diets for their disease. This information may be useful for treating or designing nutritional studies for cats with CKD.

Preliminary pharmacokinetics and cardiovascular effects of fenoldopam continuous rate infusion in six healthy dogs

Fenoldopam is a selective dopamine-1 receptor agonist that causes peripheral arterial vasodilation, increased renal blood flow, and diuresis. Enthusiasm exists for the use of fenoldopam in nonpolyuric kidney injury in dogs, although pharmacokinetic data are lacking. The purpose of this study was to collect basic pharmacokinetic and hemodynamic effect data for fenoldopam when administered to healthy awake dogs. Six healthy, awake beagles were given a 180-min fenoldopam constant rate infusion at 0.8 μg/kg per minute followed by a 120-min washout period. Citrated blood was collected during and after infusion for the measurement of plasma fenoldopam concentration by HPLC with mass spectrometry. Heart rate and indirect systolic blood pressure were concurrently measured. Mean ± SD, steady-state plasma fenoldopam concentrations of 20 ± 17 ng/mL were achieved within 10 min of starting the infusion. Area under the plasma concentration-time curve was 3678 ± 3030 ng/mL · min, and plasma clearance was 66 ± 43 mL/min per kg. Elimination was rapidly achieved in all dogs. Heart rate and systolic blood pressure were unaffected by the fenoldopam infusion. Based on the results of this study, further evaluation of the effects of fenoldopam in dogs at differing doses and in dogs with clinical conditions such as acute nonpolyuric kidney injury is warranted.

Peritoneal dialysis in cats with acute kidney injury: 22 cases (2001-2006)

BACKGROUND

Peritoneal dialysis (PD) has been described for use in animals with acute kidney injury refractory to fluid therapy. However, no study has examined the use of PD in a large group of cats.

HYPOTHESIS

PD is an important adjunctive therapy to treat acute kidney injury in cats.

ANIMALS

The medical records of 22 cats with acute kidney injury that had received PD were examined. Animals were excluded if acute uremia was a result of postrenal causes such as uroabdomen or urethral obstruction.

METHODS

Medical records were reviewed for the following: indication for PD, outcome, number of cycles performed, survival time, and predialysis and postdialysis results for blood urea nitrogen (BUN), creatinine, potassium, chloride, sodium, phosphorus, total protein, and albumin concentrations, and urine output.

RESULTS

Indications for PD include acute-on-chronic kidney injury, acute kidney injury caused by toxins, bilateral ureteroliths, bilateral ureteral ligation as a complication of ovariohysterectomy, and unknown causes. The median survival time for all cats on PD was 4 days, although the median survival time for the cats that were discharged was 774 days. The most common complications were dialysate retention and sequestration of dialysate SC. There was a significant (P < .05) decrease between predialysis and postdialysis results for BUN, creatinine, potassium, phosphorus, total protein, and albumin concentrations. There was a significant (P < .05) difference in survival times between sexes.

CONCLUSIONS AND CLINICAL IMPORTANCE

PD is an effective option for treatment of cats with acute kidney injury refractory to fluid therapy.

ACVIM small animal consensus statement on Lyme disease in dogs: diagnosis, treatment, and prevention

The purpose of this report is to offer a consensus opinion of ACVIM diplomates on the diagnosis, treatment, and prevention of Borrelia burgdorferi infections in dogs (canine Lyme disease). Clinical syndromes known to commonly be associated with canine Lyme disease include polyarthritis and glomerulopathy. Serological test results can be used to document exposure to B. burgdorferi but not prove illness. Although serum enzyme-linked immunosorbent assay/indirect fluorescent antibody assay titers can stay positive for months to years after treatment, quantitative C6 peptide antibody paired tests need more study. Serological screening of healthy dogs is controversial because it can lead to overdiagnosis or overtreatment of normal dogs, most of which never develop Lyme disease. However, serological screening can provide seroprevalence and sentinel data and stimulate owner education about tick infections and control. Although it is unknown whether treatment of seropositive healthy dogs is beneficial, the consensus is that seropositive dogs should be evaluated for proteinuria and other coinfections and tick control prescribed. Tick control can include a product that repels or protects against tick attachment, thereby helping to prevent transmission of coinfections as well as Borrelia spp. Seropositive dogs with clinical abnormalities thought to arise from Lyme disease generally are treated with doxycycline (10 mg/kg q24h for 1 month). Proteinuric dogs might need longer treatment as well as medications and diets for protein-losing nephropathy. The ACVIM diplomates believe the use of Lyme vaccines still is controversial and most do not administer them. It is the consensus opinion that additional research is needed to study predictors of illness, "Lyme nephropathy," and coinfections in Lyme endemic areas.

Retrospective evaluation of partial parenteral nutrition in dogs and cats

The purpose of this retrospective study was to evaluate the use of partial parenteral nutrition (PPN) in dogs and cats. The medical records of all dogs and cats receiving PPN between 1994 and 1999 were reviewed to determine signalment, reasons for use of PPN, duration of PPN administration, duration of hospitalization, complications, and mortality. Complications were classified as metabolic, mechanical, or septic. One hundred twenty-seven animals (80 dogs and 47 cats) were included in the study, accounting for 443 patient days of PPN. The most common underlying diseases were pancreatitis (n = 41), gastrointestinal disease (n = 33), and hepatic disease (n = 23). Median time of hospitalization before initiation of PPN was 2.8 days (range, 0.2-10.7 days). Median duration of PPN administration was 3.0 days (range, 0.3-8.8 days). Median duration of hospitalization was 7 days (range, 2-20 days). In the 127 animals receiving PPN, 72 complications occurred. These included metabolic (n = 43), mechanical (n = 25), and septic (n = 4) complications. The most common metabolic complication was hyperglycemia (n = 19), followed by lipemia (n = 17) and hyperbilirubinemia (n = 6). Most complications were mild and did not require discontinuation of PPN. Ninety-three (73.2%) of the 127 patients were discharged. All 4 animals with septic complications were discharged from the hospital. The presence, type, and number of complications did not impact the duration of hospitalization or outcome. However, animals that received supplemental enteral nutrition survived more often than those receiving PPN exclusively. Although PPN seems to be a relatively safe method of providing nutritional support, future studies are warranted to determine its efficacy.

Strategies for management of acute renal failure

Acute renal failure (ARF) is often defined as the sudden inability of the kidneys to regulate water and solute balance. ARF may be more broadly defined as rapid deterioration of renal function resulting in the accumulation of nitrogenous wastes such as urea and creatinine. Clinically, oliguria is defined as urine flow of less than 2 mL/kg/h and anuria has no measurable urine production. In animals, the most common cause of ARF is nephrotoxicity; ischemia ranks second, with interstitial and glomerular diseases following.

Ultrasonography of the normal feline pancreas and associated anatomic landmarks: a prospective study of 20 cats

The sonographic appearance of the feline pancreas and associated anatomic landmarks including the pancreatic duct, duodenum, duodenal papilla, portal vein, and gastric lymph node were evaluated in 20 healthy, awake cats. The pancreas appeared nearly isoechoic to surrounding mesenteric tissues, isoechoic to slightly hyperechoic to adjacent liver lobes, and hypoechoic to the spleen. The mean thickness measurements for the right pancreatic lobe, body, and left pancreatic lobe were 4.5 mm (range 2.8-5.9), 6.6 mm (range 4.7-9.5), and 5.4 mm (range 3.4-9.0), respectively. The pancreatic duct was consistently visualized in the left pancreatic lobe and had a mean thickness of 0.8 mm (range 0.5-1.3). It could be differentiated from the pancreatic vessel, by its central location, and the duct's lack of Doppler flow signal. The duodenum was used as a landmark to identify the right lobe of the pancreas. The mean duodenal wall thickness measurement was 2.8 mm (range 2.1-3.8) in sagittal section, and 3.0 mm (range 2.2-4.4) in transverse section. The duodenal papilla was identified in 4 of 20 cats. It ranged in size from 2.9 to 5.5 mm in width, and had a maximum height of 4.0 mm in transverse section. The portal vein was used as a consistent anatomic landmark for identification of the left lobe and body of the pancreas. The mean diameter of the portal vein at the level where the pancreatic body joins the left pancreatic lobe was 4.3 mm (range 2.7-5.9) when viewed in sagittal section, and 4.5 mm (range 3.6-6.1) in transverse section. The gastric lymph node was identified cranial and ventromedial to the pyloroduodenal angle in 6 of 20 cats. It had an asymmetrical shape with a larger caudal pole in five of the six cats. The largest dimensions of the gastric lymph node were 10 mm in length, and 6 mm in width for the larger caudal pole, and 5.1 mm in width for the smaller cranial pole.

Peritoneal dialysis in emergency and critical care medicine

Peritoneal dialysis is a technique that has been used to treat acute renal failure in humans since 1923. Peritoneal dialysis is used in people to manage acute and chronic renal failure, as well as to remove dialyzable toxins (ethylene glycol, barbiturates, and ethanol), reduce severe metabolic disturbances, and for the treatment of peritonitis, pancreatitis, uroabdomen, hypothermia, and fluid overload. In veterinary medicine, acute renal failure is the prevailing indication for dialysis. This report will discuss the pathophysiology of peritoneal dialysis, indications, and contraindications. Catheter selection and placement will be reviewed. Types of dialysate solution will be discussed and the protocol established for instituting peritoneal dialysis. The report will conclude with a discussion of potential complications and methods to minimize them.

Familial glomerulonephropathy in a litter of beagles

Membranoproliferative glomerulonephropathy was diagnosed in 5 of 7 adult Beagles from the same litter. Dogs were raised in more than 1 area of the United States. One died without evidence of renal disease when it was 3 years old. At 8 years of age, 2 dogs developed signs of uremia, including polyuria, polydipsia, and infrequent episodes of anorexia and vomiting. Serum biochemical variables and urine specific gravity values were consistent with renal azotemia. Both dogs had proteinuria. Although healthy, 3 of the 4 remaining Beagles had proteinuria. Of these 3, only 1 was azotemic. Membranoproliferative glomerulonephritis was diagnosed on the basis of results of histologic examination of renal biopsy specimens from 4 of the dogs. Electron microscopy performed on 3 of the renal biopsy specimens revealed identical lesions, consisting of an extremely thickened glomerular basement membrane with multilaminar splitting. Immunoglobulin or amyloid deposits were not detected. On the basis of similar clinicopathologic abnormalities, common genetic background, and identical histopathologic and electron microscopic findings, familial renal disease was diagnosed. Additional studies involving other related Beagles are needed to identify the hereditary nature of membranoproliferative glomerulonephropathy in Beagles.

Management of the uncomplicated canine diabetic

Managing the uncomplicated canine diabetic may still be a challenging endeavor. Client education is the most important treatment to provide. The client must understand the technique of drug handling and administration, the importance of diet in treating the animal, how to handle an emergency situation, and, most importantly, the disease itself. The clinician must realize that although "tight" glycemic control is the optimal goal; the reality is often a compromise of mild hyperglycemia with resolution of clinical signs. When regulation cannot be maintained it is necessary to investigate the causes of insulin resistance.

Use of synthetic prostaglandin E1 (misoprostol) for prevention of aspirin-induced gastroduodenal ulceration in arthritic dogs

A randomized, double-blind, controlled study was performed with 18 arthritic dogs administered aspirin (25 mg/kg of body weight, PO, q 8 h) and excipient (control group) or aspirin and misoprostol (100 micrograms, PO, q 8 h). Dogs in the misoprostol (n = 10) and control (n = 8) groups were primarily compared by use of sequential gastroduodenoscopy, changes in PCV, and prevalence of clinical signs of gastrointestinal disturbance over a 14-day treatment period. The misoprostol/aspirin-treated group had significantly (P < 0.05) less gastroduodenal hemorrhage and ulceration and a significantly (P < 0.05) lower prevalence of vomiting than did the control group.

Plasma disappearance of creatinine as a renal function test in the dog

The serum concentration of creatinine at 120 minutes (SC120) after intravenous injection of 88 mg kg-1 of creatinine, the plasma half-life (t1/2) and the plasma clearance of creatinine (PCC) were evaluated as renal function tests in 30 healthy adult dogs and six adult dogs with known or suspected renal disease. The mean SC120 in the normal dog was 0.31 +/- 0.08 mmol litre-1 and in the clinical cases 0.71 +/- 0.19 mmol litre-1. The correlation coefficients between SC120 and renal creatinine clearance (RCC) for the normal dogs and the clinical cases were -0.76 and -0.69, respectively. At 120 minutes after injection, 95 per cent of normal dogs would be predicted to have a serum creatinine concentration below 0.46 mmol litre-1. The mean plasma t1/2 of creatinine for the normal dogs was 107.7 +/- 17.96 minutes, while the clinical cases had a wide range of values (148.8 to 620.1 minutes). Plasma t1/2 of creatinine was correlated with RCC for both the normal dogs and the clinical cases (r = -0.55, r = -0.91, respectively). The mean PCC for the normal dogs was 7.42 +/- 2.22 ml min-1 kg-1 (range 4.95 to 13.28 ml min-1 kg-1). There was a good correlation between RCC and PCC (r = 0.7). The PCC for the clinical cases ranged from 0.76 to 3.37 ml min-1 kg-1. The correlation between RCC and PCC was significant (r = 0.91). Thus SC120, t1/2 and PCC may be useful methods of assessing renal function in dogs with renal impairment insufficient to cause azotaemia.

Ketoconazole therapy in a dog with systemic cryptococcosis

A 2-year-old dog had bilateral chorioretinitis and a cough. Systemic cryptococcosis was diagnosed by evaluating a trans-tracheal aspirate and a cryptococcal latex-particle agglutination antigen titer. Clinical remission was achieved with ketoconazole administration, an imidazole antifungal agent. Serial antigen titers were used to monitor treatment, which was continued for 12 months. Ketoconazole therapy was well tolerated by the dog.

Cytochemical localization of hydrogen peroxide generating sites in the rat thyroid gland

Sites of H2O2 generation in lightly prefixed, intact thyroid follicles were studied by two cytochemical reactions: peroxidase-dependent DAB oxidation and cerium precipitation. In both cases reaction product accumulated on the apical surface of the follicle cell at the membrane-colloid interface. The former reaction was inhibited by the peroxidase inhibitor, aminotriazole; both reactions were blocked by the presence of catalase. NADH in the medium slightly increased the amount of cerium precipitation. The ferricyanide technique for oxidoreductase activity was also applied; reaction product again was associated with the apical surface. These results strongly imply that the follicle cells have a NADH oxidizing system generating H2O2 at the apical plasma membrane.