Serum vitamin D metabolite and acute-phase protein concentrations are frequently abnormal in a cohort of hospitalized dogs and cats

OBJECTIVE

To determine whether serum 25-hydroxyvitamin D (25[OH]D) and 1,25-dihydroxyvitamin D (1,25[OH]2D) concentrations are associated with survival and negatively correlate with acute-phase protein (APP) concentrations in ill dogs and cats admitted to nursing care units.

ANIMALS

Client-owned dogs (n = 79) and cats (16) admitted to 2 academic veterinary hospital nursing care units.

METHODS

A prospective cohort study was conducted between August 12, 2019, and October 26, 2021. A diagnostic laboratory measured 25(OH)D, 1,25(OH)2D, and haptoglobin (HPT) in dogs and cats; C-reactive protein (CRP) in dogs; and serum amyloid A (SAA) in cats. Serum was collected within 12 hours of admission. Illness severity (acute patient physiologic and laboratory evaluation [APPLEfast]) scores and survival data were recorded.

RESULTS

Serum 25(OH)D concentrations were in the deficient range for 22 of 79 dogs and 2 of 16 cats. There were no associations between serum analyte concentrations (25[OH]D, 1,25[OH]2D, and APP) or APPLEfast score and survival in dogs or cats. In dogs, HPT was negatively correlated with 25(OH)D (P = .002; r = -0.34) and 1,25(OH)2D (P = .012; r = -0.28), while CRP was positively correlated with HPT (P = .001; r = 0.32) and APPLEfast score (P = .014; r = 0.16). In cats, 1,25(OH)2D was negatively correlated with APPLEfast scores (P = .055; r = -0.49) and SAA was positively correlated with HPT (P = .002; r = 0.73).

CLINICAL RELEVANCE

Serum 25(OH)D or 1,25(OH)2D was not associated with survival in our hospitalized patient population. Relationships between APP and serum vitamin D metabolites with APPLEfast scores in cats warrant further investigation as illness severity biomarkers.

A prospective cohort study to identify clinical diagnostic and prognostic markers of primary immune thrombocytopenia in dogs

BACKGROUND

Primary immune thrombocytopenia (pITP) in dogs presents a diagnostic challenge, and clinical markers of severity are lacking.

OBJECTIVES

Identify clinicopathologic features that differentiate pITP from secondary ITP (sITP) and markers related to bleeding severity, transfusion, and survival of dogs with pITP.

ANIMALS

Ninety-eight thrombocytopenic dogs (58 pITP and 40 sITP).

METHODS

Client-owned dogs with platelet counts <50 000/μL were enrolled in a prospective, multi-institution cohort study. History and treatment information, through a maximum of 7 days, was recorded on standard data forms. Bleeding severity was scored daily using a bleeding assessment tool (DOGiBAT). At-admission blood samples were collected for CBC, biochemistry, C-reactive protein concentration, and coagulation panels, and to measure platelet surface-associated immunoglobulin G (PSAIg) and expression of platelet membrane proteins and phospholipids. Dogs with evidence of coincident disease were classified as sITP.

RESULTS

No definitive pITP diagnostic test was found. However, pITP cases were characterized by lower platelet counts, D dimer concentrations, and platelet membrane protein expression than sITP cases. Differentiation between pITP and sITP was further enhanced using logistic regression modeling combining patient sex, coagulation profile, platelet count, D dimer, and PSAIg. A second model of pITP severity indicated that low hematocrit and high BUN concentration were associated with non-survival. Low hematocrit at admission, but not platelet count or DOGiBAT score, was associated with transfusion.

CONCLUSIONS AND CLINICAL IMPORTANCE

Pending validation studies, models constructed from at-admission clinicopathologic findings may improve differentiation of pITP from sITP and identify the most severe pITP cases at the time of presentation.

Short-term parenteral infusions with high-osmolality amino acid solutions can be safely administered through peripheral catheters in dogs treated for hypoaminoacidmia-related conditions

OBJECTIVE

To compare complications between central and peripheral administration of high-osmolarity (approx 700 to 1,000 mOsm/L) amino acid (± lipid) infusions.

ANIMALS

18 client-owned dogs diagnosed with aminoaciduric canine hypoaminoacidemic hepatopathy syndrome or superficial necrolytic dermatitis receiving parenteral amino acid ± lipid infusions.

METHODS

In this retrospective case series, medical records were reviewed for administration route (central vs peripheral), catheter details and infusion characteristics (product osmolarity, concurrent lipid administration, infusion volume, duration, and rate), and complications for each infusion.

RESULTS

18 dogs received 277 infusions (median, 8.5; range, 1 to 84). Effective infusion osmolarities were 683 mOsm/L in 22% of infusions, 791 mOsm/L in 8%, 802 mOsm/L in 2%, 837 mOsm/L in 45%, and 998 mOsm/L in 23% (65% peripheral, 35% central). Most (n = 230 [83%]) infusions were given peripherally. The osmolarities of solutions administered by each route (P = .53), the infusion rate indexed to body weight (P = .17), or the lipid infusion rates indexed to body weight (P = .89) did not differ. One dog suffered 2 complications in 63 infusions-1 mild, 1 severe-both occurring with peripheral infusions. Thus, the overall complication rate was 2 of 277 (0.9%) infusions.

CLINICAL RELEVANCE

Short-term peripherally administered amino acid ± lipid infusions < 1,000 mOsm/L confer little risk compared to centrally administered infusions. Additional studies are needed to determine the safety of infusions with longer durations. Due to the relative ease of peripheral catheterization, clinicians should consider this route for medically managing aminoaciduric canine hypoaminoacidemic hepatopathy syndrome and superficial necrolytic dermatitis in dogs.

Untargeted metabolomic profiles reveal widespread metabolic perturbations and identify candidate biomarkers in aminoaciduric canine hypoaminoacidemic hepatopathy syndrome

OBJECTIVE

To identify metabolites and metabolic pathways affected in dogs with aminoaciduric canine hypoaminoacidemic hepatopathy syndrome (ACHES) compared to healthy control (CON) dogs of similar ages and breeds. To improve our understanding of ACHES pathophysiology and identify novel candidate biomarkers associated with ACHES.

ANIMALS

A prospective case-control study. Privately owned dogs with ACHES (n = 19) and healthy (CON) dogs (n = 9) were recruited between February 18, 2015, and April 18, 2018.

METHODS

A prospective case-control study. Plasma and urine were collected from ACHES and CON dogs. The Cornell University Proteomics and Metabolomics Core Facility conducted an untargeted metabolomic analysis.

RESULTS

After controlling for age, sex, and weight, 111 plasma and 207 urine metabolites significantly differed between ACHES and CON dogs. Data reduction and cluster analysis revealed robust segregation between ACHES and CON dogs. Enrichment analysis of significant compounds in plasma or urine identified altered metabolic pathways, including those related to AA metabolism, cellular energetics, and lipid metabolism. Biomarker analysis identified metabolites that best-distinguished ACHES from CON dogs, including pyruvic acid isomer and glycerol-3-phosphate in the plasma and an alanine isomer and choline in the urine.

CLINICAL RELEVANCE

Our findings provide an in-depth analysis of metabolic perturbations associated with ACHES. Several affected metabolic pathways (eg, lipid metabolism) offer a new understanding of ACHES pathophysiology. Novel candidate biomarkers warrant further evaluation to determine their potential to aid in ACHES diagnosis, prognosis, and treatment monitoring.

Randomized controlled trial of hydrolyzed fish diets in dogs with chronic enteropathy

BACKGROUND

The role of diet in the pathogenesis and treatment of chronic enteropathies (CE) in dogs is unresolved.

OBJECTIVES

To compare the ability of diets composed of hydrolyzed fish, rice starch, and fish oil without (HF) or with prebiotics, turmeric, and high cobalamin (HF+) against a limited ingredient diet containing mixed nonhydrolyzed antigens and oils (control) to resolve clinical signs and maintain serum cobalamin and folate concentrations in dogs with nonprotein losing CE (non-PLE). To determine the ability of hydrolyzed fish diets to support recovery and remission in dogs with PLE.

ANIMALS

Thirty-one client-owned dogs with CE: 23 non-PLE, 8 PLE.

METHODS

Randomized, blinded, controlled trial. Diets were fed for 2 weeks; responders continued for 12 weeks. Nonresponders were crossed over to another diet for 12 weeks. Response was determined by standardized clinical evaluation with long-term follow-up at 26 weeks. Concurrent medications were allowed in PLE.

RESULTS

Nineteen of 23 (83%; 95% confidence interval [CI], 60%-94%) non-PLE CE responded clinically to their initial diet, with no difference between diets (P > .05). Four nonresponders responded to another diet, with sustained remission of 18/18 (100%; 95%CI, 78%-100%) at 26 weeks. Serum cobalamin concentration was increased (P < .05) and maintained by diet. Serum folate concentration decreased posttreatment (P < .05) but was restored by dietary supplementation. Hydrolyzed fish diets supported weight gain, serum albumin concentration, and recovery (P < .05) in dogs with PLE.

CONCLUSIONS AND CLINICAL IMPORTANCE

Changing diet, independent of antigen restriction or supplemental ingredients, induced long-term remission in dogs with non-PLE CE. Serum cobalamin and folate concentrations were maintained by diet. Hydrolyzed fish diets supported clinical recovery and remission in PLE.

Low alanine aminotransferase activity gene variant in a Siberian Husky with copper-associated hepatopathy

BACKGROUND

Alanine aminotransferase (ALT) is commonly used as a marker of hepatocellular injury. Increased serum ALT activity due to hepatocyte injury occurs in copper-associated hepatopathy (CuCH) and other necroinflammatory liver conditions. Blood ALT concentrations are frequently used to monitor therapy in cases of CuCH. Low serum ALT activities have been associated with an allele at a CFA13 locus.

CASE PRESENTATION

A 9-year-old female spayed Siberian Husky was diagnosed with CuCH (hepatic copper dry weight 2680 µg/g [normal, 120-400 µg/g; toxic, > 1500 µg/g]) and a normal ALT (78 U/L; reference range, 10-125 U/L). Mild hepatocellular necrosis was evident histologically. Genetic testing (Embark) revealed that the dog was heterozygous for the low ALT activity gene allele.

CONCLUSIONS

This case report illustrates the clinical implications for diagnosing and managing necroinflammatory liver disease such as CuCH in dogs with a low ALT activity genotype.

Laparoscopic twist technique has the best overall artifact profile when comparing three laparoscopic hepatic cup biopsy techniques for dogs

OBJECTIVE

To determine the difference in histologic artifacts and morphologic diagnosis among 3 laparoscopic cup biopsy forceps techniques and wedge hepatic samples.

ANIMALS

Cadavers of 20 client-owned dogs following euthanasia for unrelated reasons between January 3 and July 29, 2021.

PROCEDURES

Four biopsy techniques were performed from the margin of 3 liver lobes/dog. Laparoscopic techniques used 5-mm cup biopsy forceps to obtain biopsy samples by pulling the forceps forcefully caudally to free a sample (the PULL technique), rotating the forceps 360° in 1 direction until freed (the TWST technique), or pulling the forceps through a 5-mm cannula to remove the sample (the CAN technique); wedge biopsy samples served as the control (CON). Data collected included sample weight, histologic features, diagnosis, and artifact characterization. Gwet AC1 or intraclass correlation coefficients (ICCs) were calculated to detect agreement among techniques.

RESULTS

Sample weights for CON and TWST were significantly larger (P < .001 and P = .035, respectively) than for PULL and CAN. There was excellent agreement among all techniques for most diagnostic features (Gwet AC1, 0.93 to 1). The TWST technique resulted in the best overall artifact profile for laparoscopic techniques, with 90% of samples (54/60) having crisp edges and 65% of samples (39/60) having no or mild tearing. The agreement was moderate to good (ICC, 0.73 for edges and 0.76 for tearing) among all cup biopsy forceps techniques.

CLINICAL RELEVANCE

The TWST technique resulted in the largest sample and had the fewest artifacts, supporting its continued use during laparoscopic procedures.

Complex Feline Disease Mapping Using a Dense Genotyping Array

The current feline genotyping array of 63 k single nucleotide polymorphisms has proven its utility for mapping within breeds, and its use has led to the identification of variants associated with Mendelian traits in purebred cats. However, compared to single gene disorders, association studies of complex diseases, especially with the inclusion of random bred cats with relatively low linkage disequilibrium, require a denser genotyping array and an increased sample size to provide statistically significant associations. Here, we undertook a multi-breed study of 1,122 cats, most of which were admitted and phenotyped for nine common complex feline diseases at the Cornell University Hospital for Animals. Using a proprietary 340 k single nucleotide polymorphism mapping array, we identified significant genome-wide associations with hyperthyroidism, diabetes mellitus, and eosinophilic keratoconjunctivitis. These results provide genomic locations for variant discovery and candidate gene screening for these important complex feline diseases, which are relevant not only to feline health, but also to the development of disease models for comparative studies.

Assessment of Sex, Age, and Metabolism Relationships to Serum Thyroid Concentrations in Retired Alaskan Husky Sled Dogs

Sled dogs are purpose-bred dogs selected for endurance work. Prior studies in racing dogs showed that serum thyroid parameters (total T4, free T4, and T3) are lower than the reference range in approximately 25% of dogs. Whether this is related to training, breeding, or body condition remains unclear. We hypothesized that retired sled dogs of normal body condition (9–13 years old) would have predominantly normal serum thyroid parameters and that serum thyroid status would be correlated to energy consumption based on metabolic body weight. Eighty-six sled dogs who were deemed healthy on physical exam, not on confounding medications, and without a prior diagnosis of hypothyroidism were included. All dogs' mean body condition scores were 5.1 ± 0.4 and body weight 24.5 ± 4.2 kg at fasting blood collection with stable dietary intake for 3 months before sampling. The total T4, free T4, and T3 serum concentrations were 23.4 ± 9.1 nmol/L, 9.53 ± 4.3 pmol/L, and 0.93 ± 0.39 nmol/L, respectively, with 38% lower than the reference range for total T4, 45% for free T4, and 37% for T3. All dogs were negative for thyroglobulin antibody, and TSH results were within normal ranges. Pearson's correlates based on kilocalories consumed on a metabolic body weight basis for total T4 (R = 0.14), free T4 (R = 0.01) and T3 (R = 0.23) showed poor correlation. No differences were observed between thyroid hormones and age, breed, or sex. Inactive, retired sled dogs can be misdiagnosed with hypothyroidism; therefore, our data suggests that misdiagnosis of hypothyroidism can occur and that the racing Alaskan sled dog has a unique reference range that should be considered when assessing serum thyroid status.

Plasma concentrations of glucagon and glucagon-like peptide-1 are reduced in dogs with aminoaciduric canine hypoaminoacidemic hepatopathy syndrome versus healthy dogs: a preliminary study

OBJECTIVE

To compare plasma concentrations of glucagon and glucagon-like peptide-1 (GLP-1) between healthy dogs and dogs with aminoaciduric canine hypoaminoacidemic hepatopathy syndrome (ACHES) dogs.

ANIMALS

Privately owned healthy (n = 5) control (CON) and ACHES (8; including 3 with diabetes mellitus) dogs enrolled between October 2, 2019, and March 4, 2020.

PROCEDURES

This was a prospective case-control study. Fasting and 15-minute postprandial plasma glucagon total GLP-1 concentrations were measured with commercial immunoassays.

RESULTS

Dogs with ACHES had lower fasting (median, 0.5; mean difference, 3.8; 95% CI, 0.52 to 7.0 pmol/L; P = .021) and postprandial (median, 0.35; mean difference, 5.0; 95% CI, 1.8 to 8.3 pmol/L; P = .002) plasma glucagon concentrations than CON (fasting and postprandial medians, 3.5 and 4.6 pmol/L, respectively). ACHES dogs had significantly (median, 4.15; mean difference, 12.65; 95% CI, 2.0 to 16.3 pg/ml; P = .011) lower postprandial plasma GLP-1 concentrations than CON (median, 16.8 pg/ml). There was no significant difference between fasting GLP-1 levels between the 2 groups.

CLINICAL RELEVANCE

Lower postprandial plasma GLP-1 concentrations may contribute to the propensity of diabetes mellitus in ACHES. Lower glucagon concentrations may reflect an appropriate physiologic response to hypoaminoacidemia.

Treatment and outcomes of dogs with hepatocutaneous syndrome or hepatocutaneous-associated hepatopathy

BACKGROUND

Superficial necrolytic dermatitis (SND) in dogs is a rare disorder most commonly associated with hepatocutaneous syndrome. Although often reported as fatal, sporadically reported long-term remissions might be more common than previously believed and linked to treatment regimens.

HYPOTHESIS/OBJECTIVES

Evaluate treatments and associated outcomes in dogs with hepatocutaneous-associated hepatopathy (HCH) with or without SND, designated collectively aminoaciduric canine hypoaminoacidemic hepatopathy syndrome (ACHES).

ANIMALS

Forty-one dogs of various breeds and ages diagnosed with ACHES.

METHODS

Retrospective study. Electronic surveys, medical records (2014-2019), and communication with veterinarians provided data. Three treatment categories were each dichotomized: IV amino acid (IV-AA) infusions (≥2 vs <2), supplements including S-adenosylmethionine (SAMe), arginine with ornithine, glutathione, lysine, proline, omega-3 fatty acids, or zinc (≥3 vs <3), and diet type (home-cooked vs commercial). Optimal treatment was defined as receiving ≥2 IV-AA treatments, ≥3 nutritional supplements, and a home-cooked diet.

RESULTS

Most dogs (29/41, 71%) received IV-AA infusions (23/29, ≥2 infusions). Twenty-one dogs (51%) were fed commercial diets; 17/41 (41%) were fed home-cooked diets. Most dogs received SAMe (32/41, 78%) and a median of 3 supplements. In 4 dogs, HCH remission occurred. Overall all-cause median survival time (MST) was 359 days, and disease-specific MST was 557 days (range, 1-1783 days). Optimally treated dogs (n = 9) lived significantly longer (MST, >1783 days, P = .02) than variably treated dogs (MST, 214 days).

CONCLUSIONS AND CLINICAL IMPORTANCE

Optimized ACHES management can resolve SND and HCH and confer long-term survival.

Clinical features and amino acid profiles of dogs with hepatocutaneous syndrome or hepatocutaneous-associated hepatopathy

BACKGROUND

Superficial necrolytic dermatitis (SND), hepatocutaneous-associated hepatopathy (HCH), aminoaciduria, and hypoaminoacidemia define hepatocutaneous syndrome (HCS) in dogs. Dogs without SND but that possess all other syndrome components are not well described.

HYPOTHESIS/OBJECTIVES

To define an inclusive syndrome, aminoaciduric canine hypoaminoacidemic hepatopathy syndrome (ACHES) for dogs with HCH or HCS. Compare clinical features, salient clinicopathologic variables, and plasma and urine amino acid (AA) profiles among ACHES cases by skin lesion status.

ANIMALS

Dogs of various breeds and ages diagnosed with ACHES (n = 41). A control (CON) cohort (n = 12) provided AA profile data.

METHODS

Retrospective case series. Available medical records of previously identified cases were reviewed for salient clinical features and clinical pathology data. Plasma and urine AA profiles were performed. Cutaneous lesion status was classified as none, mild, or fulminant.

RESULTS

Thirty cases (73%) developed SND at some time. Dogs with fulminant skin lesions at diagnosis (n = 22/41, 54%) had significantly lower hematocrit (P = .05) and mean corpuscular volume (P = .01) than dogs without SND. Principal component analysis of plasma AA profiles identified distinct clustering of CON from ACHES dogs, but not by skin lesion status. Plasma 1-methylhistidine (<7 nmol/mL) and cystathionine (<7.5 nmol/mL) were robust ACHES biomarkers. Urine lysine (>344 nmol/mg creatinine) and methionine (>68 nmol/mg creatinine) also were useful ACHES biomarkers.

CONCLUSIONS AND CLINICAL IMPORTANCE

Specific AA biomarkers provide additional diagnostic utility in ACHES. Data suggests that HCH is an early stage, and SND a later stage manifestation of ACHES.

Development of infrastructure for a systemic multidisciplinary approach to study aging in retired sled dogs

Canines represent a valuable model for mammalian aging studies as large animals with short lifespans, allowing longitudinal analyses within a reasonable time frame. Moreover, they develop a spectrum of aging-related diseases resembling that of humans, are exposed to similar environments, and have been reasonably well studied in terms of physiology and genetics. To overcome substantial variables that complicate studies of privately-owned household dogs, we have focused on a more uniform population composed of retired Alaskan sled dogs that shared similar lifestyles, including exposure to natural stresses, and are less prone to breed-specific biases than a pure breed population. To reduce variability even further, we have collected a population of 103 retired (8-11 years-old) sled dogs from multiple North American kennels in a specialized research facility named Vaika. Vaika dogs are maintained under standardized conditions with professional veterinary care and participate in a multidisciplinary program to assess the longitudinal dynamics of aging. The established Vaika infrastructure enables periodic gathering of quantitative data reflecting physical, physiological, immunological, neurological, and cognitive decline, as well as monitoring of aging-associated genetic and epigenetic alterations occurring in somatic cells. In addition, we assess the development of age-related diseases such as arthritis and cancer. In-depth data analysis, including artificial intelligence-based approaches, will build a comprehensive, integrated model of canine aging and potentially identify aging biomarkers that will allow use of this model for future testing of antiaging therapies.

Diffusion tensor-based analysis of white matter in the healthy aging canine brain

White matter dysfunction and degeneration have been a topic of great interest in healthy and pathological aging. While ex vivo studies have investigated age-related changes in canines, little in vivo canine aging research exists. Quantitative diffusion MRI such as diffusion tensor imaging (DTI) has demonstrated aging and neurodegenerative white matter changes in humans. However, this method has not been applied and adapted in vivo to canine populations. This study aimed to test the hypothesis that white matter diffusion changes frequently reported in human aging are also found in aged canines. The study used Tract Based Spatial Statistics (TBSS) and a region of interest (ROI) approach to investigate age related changes in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AxD) and radial diffusivity (RD). The results show that, compared to younger animals, aged canines have significant decreases in FA in parietal and temporal regions as well as the corpus callosum and fornix. Additionally, AxD decreases were observed in parietal, frontal, and midbrain regions. Similarly, an age- related increase in RD was observed in the right parietal lobe while MD decreases were found in the midbrain. These findings suggest that canine samples show commonalities with human brain aging as both exhibit similar white matter diffusion tensor changes with increasing age.

In vivo detection of microstructural spinal cord lesions in dogs with degenerative myelopathy using diffusion tensor imaging

Background

Degenerative myelopathy (DM) in dogs is a progressive neurodegenerative condition that causes white matter spinal cord lesions. These lesions are undetectable on standard magnetic resonance imaging (MRI), limiting diagnosis and monitoring of the disease. Spinal cord lesions cause disruption to the structural integrity of the axons causing water diffusion to become more random and less anisotropic. These changes are detectable by the technique of diffusion tensor imaging (DTI) which is highly sensitive to diffusion alterations secondary to white matter lesion development.

Objective

Perform spinal DTI on cohorts of dogs with and without DM to identify if lesions caused by DM will cause a detectable alteration in spinal cord diffusivity that correlates with neurological status.

Animals

Thirteen dogs with DM and 13 aged‐matched controls.

Methods

All animals underwent MRI with DTI of the entire spine. Diffusivity parameters fractional anisotropy (FA) and mean diffusivity (MD) were measured at each vertebral level and statistically compared between groups.

Results

Dogs with DM had significant decreases in FA within the regions of the spinal cord that had high expected lesion load. Decreases in FA were most significant in dogs with severe forms of the disease and correlated with neurological grade.

Conclusions and Clinical Importance

Findings suggest that FA has the potential to be a biomarker for spinal cord lesion development in DM and could play an important role in improving diagnosis and monitoring of this condition.

Stereotactic Cortical Atlas of the Domestic Canine Brain

The domestic canine (canis familiaris) is a growing novel model for human neuroscientific research. Unlike rodents and primates, they demonstrate unique convergent sociocognitive skills with humans, are highly trainable and able to undergo non-invasive experimental procedures without restraint, including fMRI. In addition, the gyrencephalic structure of the canine brain is more similar to that of human than rodent models. The increasing use of dogs for non-invasive neuroscience studies has generating a need for a standard canine cortical atlas that provides common spatial referencing and cortical segmentation for advanced neuroimaging data processing and analysis. In this manuscript we create and make available a detailed MRI-based cortical atlas for the canine brain. This atlas includes a population template generated from 30 neurologically and clinically normal non-brachycephalic dogs, tissue segmentation maps and a cortical atlas generated from Jerzy Kreiner's myeloarchitectonic-based histology atlas. The provided cortical parcellation includes 234 priors from frontal, sensorimotor, parietal, temporal, occipital, cingular and subcortical regions. The atlas was validated using an additional canine cohort with variable cranial conformations. This comprehensive cortical atlas provides a reference standard for canine brain research and will improve and standardize processing and data analysis and interpretation in functional and structural MRI research.

Common bile duct obstruction palliated with common bile duct re-implantation (choledochoduodenostomy) in a cat

A cat was presented with complete biliary obstruction at the level of the distal common bile duct (CBD), with loss of normal architecture. The area was excised and submitted for histopathology. Concurrent cholecystitis and gall bladder necrosis necessitated cholecystectomy. The proximal CBD was preserved and re-implanted adjacent to the original duodenal papilla. The cat recovered and remained asymptomatic for 6 months. At clinical relapse a carcinoma of suspected biliary origin was confirmed, and the cat was euthanized. In situations in which the CBD lumen cannot be re-established, the pathology is limited to the distal CBD, and the gall bladder is not available for cholecystoenterostomy, CBD re-implantation may be an option to salvage and retain a functional biliary tree.

Serum Vitamin D Metabolites and CXCL10 Concentrations Associate With Survival in Dogs With Immune Mediated Disease

Background: Low vitamin D increases the risk of immune-mediated disease (IMD) in human beings and rodent models. Vitamin D metabolites, particularly 1,25(OH)2D3, modulate gene expression of immune cells and may attenuate immune pathways that drive IMD.

Hypothesis/objectives: Our primary hypothesis was that serum 25(OH)D3 and 1,25(OH)2D3, are reduced in patients with IMD and associate with poorer outcomes. We secondarily hypothesized serum 24,25(OH)2D3 would not be associated with disease or outcome. We also measured serum CXCL10 concentrations to determine if an increase occurs in dogs with IMD and in association with poorer survival.

Animals: We enrolled dogs diagnosed with IMD (n = 29) and healthy control dogs (n = 9) in the study with informed client consent.

Methods: Serum was collected and stored at −80°C until analyses. Serum vitamin D metabolites were measured by LC-MS/MS by an accredited laboratory. A commercially available canine-specific ELISA kit measured serum CXCL10.

Results: Serum 25(OH)D3 and 1,25(OH)2D3 were significantly reduced in dogs (n = 25) with IMD. Serum CXCL10 concentrations undetectable in all controls, and were 30 times higher overall in IMD dogs (n = 25; P = 0.004). CXL10 was, however, undetectable in 40% of dogs with IMD. Of the 60% of IMD dogs with increased CXCL10 concentrations, 5/25 had concentrations at the upper limit of quantification. The survival of those five dogs was significantly (P = 0.049) shorter (72 days) than all other dogs with IMD with measured CXCL10 concentrations. The median survival time (MST) for dogs with 25(OH)D3 concentrations ≤ the median was 106 days, while dogs with concentrations of 25(OH)D3 > the median did not achieve an MST.

Conclusions and clinical importance: Serum 25(OH)D3 and 1,25(OH)2D3, but not 24,25(OH)2D3 levels are reduced dogs with IMD. Vitamin D metabolites and CXCL10 may be useful prognostic markers and may be targets for adjunct therapy in canine IMD. These data support the future investigation of vitamin D analogs in the treatment of canine IMD.

One-year study evaluating efficacy of an iodine-restricted diet for the treatment of moderate-to-severe hyperthyroidism in cats

PURPOSE

This study sought to determine the efficacy of a therapeutic iodine-restricted diet during a 12 -month interval in cats with moderately to severely increased total thyroxine (TT4) concentrations.

PATIENTS AND METHODS

Eight hyperthyroid cats with serum creatinine <2.0 mg/dL and TT4 >6.0 µg/dL (reference interval 1.5-4.0 µg/dL) were enrolled. Each cat underwent an initial physical examination, complete blood count, serum chemistry panel, thyroid profile, thyroid scintigraphy, and echocardiogram. Physical examination and all blood samplings were repeated at 1, 2, 3, 6, and 12 months after enrollment. Clients were instructed to feed only the therapeutic iodine-restricted diet throughout the entire study.

RESULTS

Median TT4 was 8.4 (range 6.2-24.0) µg/dL at study onset. Thyroid scintigraphy was abnormal in all cats, confirming hyperthyroidism. Six out of eight cats had normal serum TT4 after 4 weeks of feeding the therapeutic diet. The two cats that did not achieve normalization of TT4 at 4 weeks had the highest initial TT4 concentrations. Three cats were withdrawn from the study due to emergence of chronic kidney disease.

CONCLUSION

An iodine-restricted diet was able to control moderate-to-severe hyperthyroidism in most (six out of eight) of the cats by 4 weeks. Cats with highest baseline TT4 took substantially longer before TT4 concentrations normalized, if at all.

Evaluation of Arsenic, Cadmium, Lead and Mercury Contamination in Over-the-Counter Available Dry Dog Foods With Different Animal Ingredients (Red Meat, Poultry, and Fish)

Objectives: To examine the relative levels of heavy metals and arsenic content in commercial dog foods (arsenic, cadmium, lead and mercury) of 51 over-the-counter maintenance or all-life-stage dry dog foods. All products were chosen and segregated based on meat sources (fish, poultry, red-meat—17 products from each category) as animal protein sources being the primary contaminated ingredient due to bioaccumulation.

Methods: Inductively coupled plasma mass spectrometry (ICP-MS) was performed on products that were classified as fish, red meat (beef, pork, venison, bison) or poultry (chicken, turkey, duck) based. A non-Gaussian data distribution for each heavy metal within category distribution led to non-parametric statistical testing and median (range) descriptive statistics. Comparison to average human consumption based on mg/megacalorie (Mcal)was also examined.

Results: Based on caloric consumption, total arsenic and heavy metal consumption is higher in dogs than in humans; however chronic toxic exposure levels are highly unlikely. Fish-based diets had significantly higher arsenic, cadmium and mercury content than the poultry or red meat-based diets (p < 0.01). Red meat-based diets (beef, venison and bison) had higher lead concentrations than poultry and fish-based diets (p < 0.03).

Clinical Significance: Based on the findings, commercial dog foods appear to be safe for chronic consumption and concentrations of the heavy metals were dependent on primary protein sources. Overall, poultry-based diets had relatively lower heavy metal and arsenic content than red meat and fish-based diets. Despite the safety of most pet foods occasional outliers for lead render some concern for chronic exposure based on other species toxicity data and a lack of data in dogs.

Evaluation of selected ultra-trace minerals in commercially available dry dog foods

PURPOSE

To evaluate the concentrations of chromium, nickel, molybdenum, silica, and aluminum in several commercially available dry dog foods and compare these with current World Health Organization's (WHO) mean human daily dietary intake. Conversion of dietary intake per megacalorie (Mcal) for both dog foods and human average intake was performed based on the National Research Council recommendation of a 2,900 kcal diet for comparative purposes to average intake and potential toxic exposure.

MATERIALS AND METHODS

Forty-nine over-the-counter dry foods formulated for maintenance of healthy dogs yet listed as all life stage foods were analyzed. Concentrations of the ultra-trace minerals were measured via inductively coupled plasma atomic emission and represented per Mcal for comparative purposes as it relates to common intake in dogs in comparison with humans.

RESULTS

Chromium, molybdenum, and aluminum concentrations in all of the dog foods were at levels that would be considered above average human daily consumption on a caloric basis. Nickel and silica calculated intakes per Mcal were comparable with human intake patterns, while both trace minerals displayed outliers exceeding at least twofold of the upper range of human daily intake.

CONCLUSION

Overall, ultra-trace minerals found in dog foods were above the expected average daily intake for humans on a caloric basis. There was no evidence of potential chronic toxic exposure based on presumptive intake extrapolated from WHO published toxic intake concentrations for humans or domestic animals. The large range of silica intake from various foods (2.96-83.67 mg/1,000 kcal) may have health implications in dogs prone to silica urolithiasis. Further studies investigating the bioavailability of these ultra-trace minerals and establishing dietary ultra-trace mineral allowance would be ideal; however, based on these findings, consumption of these ultra-trace minerals in over-the-counter dry dog foods appears safe.

Characterization of aminoaciduria and hypoaminoacidemia in dogs with hepatocutaneous syndrome

OBJECTIVE To characterize aminoaciduria and plasma amino acid concentrations in dogs with hepatocutaneous syndrome (HCS). ANIMALS 20 client-owned dogs of various breeds and ages. PROCEDURES HCS was definitively diagnosed on the basis of liver biopsy specimens (n = 12), gross and histologic appearance of skin lesions (4), and examination of skin and liver biopsy specimens (2) and presumptively diagnosed on the basis of cutaneous lesions with compatible clinicopathologic and hepatic ultrasonographic (honeycomb or Swiss cheese pattern) findings (2). Amino acid concentrations in heparinized plasma and urine (samples obtained within 8 hours of each other) were measured by use of ion exchange chromatography. Urine creatinine concentration was used to normalize urine amino acid concentrations. Plasma amino acid values were compared relative to mean reference values; urine-corrected amino acid values were compared relative to maximal reference values. RESULTS All dogs had generalized hypoaminoacidemia, with numerous amino acid concentrations < 50% of mean reference values. The most consistent and severe abnormalities involved glutamine, proline, cysteine, and hydroxyproline, and all dogs had marked lysinuria. Urine amino acids exceeding maximum reference values (value > 1.0) included lysine, 1-methylhistidine, and proline. CONCLUSIONS AND CLINICAL RELEVANCE Hypoaminoacidemia in dogs with HCS prominently involved amino acids associated with the urea cycle and synthesis of glutathione and collagen. Marked lysinuria and prolinuria implicated dysfunction of specific amino acid transporters and wasting of amino acids essential for collagen synthesis. These findings may provide a means for tailoring nutritional support and for facilitating HCS diagnosis.

Evaluation of plasma inflammatory cytokine concentrations in racing sled dogs

In human athletes significant changes in cytokine concentrations secondary to exercise have been observed. This prospective study evaluated the effect of a multi-day stage sled dog race on plasma concentrations of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8), and interleukin-10 (IL-10). Samples from 20 dogs were harvested prior to and on days 2 and 8 of an 8-day race. Exercise resulted in significantly decreased TNF-α and IL-8 as well as increases of MCP-1, IL-6, and IL-10 concentrations (P-value between 0.01 and < 0.0001 for all parameters). The proportion of values for IL-2 that were below the detection limit increased from 40% on day 0 to 75% on day 2 and decreased on day 8 to 40% (P = 0.04). Racing sled dogs show cytokine-concentration changes that are different from those in humans.

Canine and feline obesity: a review of pathophysiology, epidemiology, and clinical management

Canine and feline obesity rates have reached pandemic proportions and are similar to those in humans, with approximately 30%-40% of dogs and cats being overweight to obese. Obesity has been associated with other health problems, including osteoarthritis, renal disease, skin disease, insulin resistance, and neoplasia in dogs, while in cats obesity is associated with dermatological issues, diabetes mellitus, neoplasia, and urolithiasis. The health issues appear to be slightly different across the two species, which may be due to some inherent differences in the hormonal milieu involved in obesity that differs between the dog and the cat. In this review, we discuss the complicated nature of the pathogenesis of obesity, the hormonal stimulus for orexigenic and anorexigenic behavior, adipose tissue as an endocrine organ, and most importantly, clinical management of the number one disease in canine and feline medicine.

Imaging diagnosis--meningoencephalitis secondary to suppurative rhinitis and meningoencephalocele infection in a dog

Nasal encephaloceles (meningoceles or meningoencephaloceles) are rare and not reported to be infected or coupled with a facial deformity in dogs. This report describes an older dog with acute worsening of seizures due to suppurative meningoencephalitis with coexisting suppurative rhinitis and infection of a meningoencephalocele. Additionally, the dog had a facial deformity for at least 5 years. The results of necropsy, computed tomography, and postmortem magnetic resonance imaging are compared. The development of nasal encephaloceles is discussed, including the potential role of early trauma, and whether separation of neural ectoderm from the surface ectoderm is part of the pathogenesis.

The effects of baicalein on canine osteosarcoma cell proliferation and death

Flavonoids are a group of modified triphenolic compounds from plants with medicinal properties. Baicalein, a specific flavone primarily isolated from plant roots (Scutellaria baicalensis), is commonly used in Eastern medicine for its anti-inflammatory and antineoplastic properties. Previous research shows greater efficacy for baicalein than most flavonoids; however, there has been little work examining their effects on sarcoma cells, let alone canine cells. Three canine osteosarcoma cell lines (HMPOS, D17 and OS 2.4) were treated with baicalein to examine cell viability, cell cycle kinetics, anchorage-independent growth and apoptosis. Results showed that osteosarcoma cells were sensitive to baicalein at concentrations from approximately 1 to 25 μM. Modest cell cycle changes were observed in one cell line. Baicalein was effective in inducing apoptosis and did not prevent doxorubicin cell proliferation inhibition in all the cell lines. The mechanism for induction of apoptosis has not been fully elucidated; however, changes in mitochondrial permeability supersede the apoptotic response.

5-lipoxygenase expression and tepoxalin-induced cell death in squamous cell carcinomas in cats

OBJECTIVE

To assess expression pattern and subcellular compartmentalization of 5-lipoxygenase in cutaneous, UV radiation-induced, and oral squamous cell carcinomas (SCCs) in cats and determine the effects of cyclooxygenase or 5-lipoxygenase inhibition on proliferation or apoptosis in a feline oral squamous cell carcinoma (SCCF1) cell line.

SAMPLE

60 archived paraffin-embedded samples of SCCs from 60 cats and SCCF1 cells.

PROCEDURES

Retrospective immunohistochemical analysis of the archived samples of SCCs (20 cutaneous, 20 UV radiation-induced, and 20 oral tumors) was performed. Cell culture proliferation assays involving SCCF1 cells were performed, and tepoxalin-induced apoptosis and signaling were examined via western blotting and annexin V staining.

RESULTS

Immunohistochemically, staining for 5-lipoxygenase was most frequently of greatest intensity in oral SCCs, whereas staining of cutaneous and UV radiation-induced lesions had less consistent 5-lipoxygenase expression. Exposure of SCCF1 cells to the 5-lipoxygenase inhibitor tepoxalin resulted in apoptosis; the effect appeared to be mediated via alteration of cell signaling rather than via suppression of lipid mediators that are typically produced as a result of 5-lipoxygenase activity.

CONCLUSIONS AND CLINICAL RELEVANCE

In cats, expression of 5-lipoxygenase in SCCs appeared to differ depending on tumor location. The influence of tepoxalin-induced 5-lipoxygenase inhibition on a 5-lipoxygenase-expressing cell line coupled with the notable expression of 5-lipoxygenase in oral SCCs suggested that 5-lipoxygenase inhibition may have therapeutic benefits in affected cats. Although the safety of tepoxalin in cats has yet to be investigated, 5-lipoxygenase inhibitors should be evaluated for use as a potential treatment for SCCs in that species.

Cloning and antibody recognition analysis of the canine 5-lipoxygenase gene

5-Lipoxygenase cDNA was prepared from canine white blood cells revealing the full-length message using an oligonucleotide capping method. The sequenced 5-Lipoxygenase open reading frame revealed a 2031 base pair message encoding a 676 amino acid protein. The amino acid sequence showed mild variation with the presumed canine sequence, as well as differences in important residues of known phosphorylation observed in other species. The sequence had between 86 and 92% homology with other species, revealing a highly conserved sequence. Confirmation of gene product identity was achieved through transient transfection of the gene in a V5-Histidine tagged pcDNA 3.1 vector into a known canine cell line. Both V5 antibody and 5-lipoxygenase antibody confirmed the gene product using Western blotting and immunoflourescence.

Combinatorial effects of interleukin 10 and interleukin 4 determine the progression of hepatic inflammation following murine enteric parasitic infection

Mice lacking the immunoregulatory cytokine interleukin 10 (IL-10) develop necrotizing hepatitis after infection with Trichinella spiralis, and inflammation is dependent on the migration of intestinally activated CD4(+) T cells into the liver. Hepatic production of IL-4 is elevated in these mice, and we hypothesized that it plays a role in the development of hepatic pathology. Wild-type (WT), IL-10 knockout (KO), IL-4 KO, and IL-10/IL-4 KO mice were orally infected, and disease progression was followed by histological examination, alanine aminotransferase assays, and flow cytometric analysis of hepatocellular content. Both IL-10 KO and IL-10/IL-4 KO mice experienced hepatocellular injury, but only IL-10 KO mice advanced to a necrotic phase. Hepatic CD4(+) T cells were the major source of IL-4, and IL-10 regulated the number of intestinally-derived CD4(+)IL-4(+) cells. Sequestration of activated neutrophils in the liver required IL-4, and neutrophil depletion prevented progression to overt necrosis. Adoptive transfer of intestinal WT CD4(+) T cells inhibited neutrophil accumulation and inflammation, but their regulatory effects did not require IL-10 signaling.

CONCLUSION

The absence of IL-10 led to hepatocyte injury during infection, but IL-4 was necessary for the development of neutrophil-dependent necrosis. These studies provide new insight into the combinatorial role of these cytokines and their targets in the generation and progression of hepatic inflammation.

Laminar xanthine oxidase, superoxide dismutase and catalase activities in the prodromal stage of black-walnut induced equine laminitis

REASONS FOR STUDY: Xanthine oxidase (XO)-dependent production of superoxide anion and hydrogen peroxide, a characteristic of ischaemia-reperfusion injury, may contribute to the development of equine laminitis.

OBJECTIVE

To determine the levels of XO and antioxidant enzymes (catalase, superoxide dismutase [SOD]) in the digital laminae of normal horses (CON) and horses in the developmental stage of laminitis using the black walnut extract (BWE) model.

METHODS

Healthy horses (n = 12) were administered BWE (BWE group, n = 6), or water (CON group, n = 6) through a nasogastric tube. At the onset of leucopenia in the BWE-treated animals, all horses were anaesthetised, digital laminae and other samples collected rapidly and flash frozen, and the animals subjected to euthanasia. Extracts of the frozen tissues were assayed for the 2 conformational forms of xanthine: oxygen oxidoreductase (XOR), namely, xanthine dehydrogenase (XDH) and xanthine oxidase (XO), as well as the antioxidant enzymes, SOD and catalase.

RESULTS

Extracts of liver, lungs and skin, but not digital laminae, from either CON or BWE-treated horses had endogenous SOD, whereas all had endogenous XO and catalase. The levels of XDH, XO and catalase were similar in extracts of laminae from CON and BWE-treated horses as was the ratio of XDH to XO in extracts.

CONCLUSIONS AND POTENTIAL RELEVANCE

The absence of increased XO activity suggest against the involvement of this reactive oxygen intermediate-generating system in the development of laminar pathology in BWE-treated horses. Conversely, the absence of SOD from extracts of equine digital laminae, but not other tissues, suggests that the equine digital laminae are highly susceptible to damage by superoxide anion, produced, for example, by emigrant inflammatory leucocytes.

Cloning and expression of ADAM-related metalloproteases in equine laminitis

Equine laminitis is a debilitating disease affecting the digital laminae that suspend the distal phalanx within the hoof. While the clinical progression of the disease has been well documented, the molecular events associated with its pathogenesis remain largely unknown. Using real time quantitative PCR (RT-qPCR), we have investigated the expression of genes coding for proteins containing a Disintegrin and Metalloprotease domain (ADAM), as well as genes encoding the natural inhibitors of these enzymes (tissue inhibitor of metalloprotease; TIMP) in horses with naturally-acquired (acute, chronic and aggravated chronic clinical cases) or experimentally-induced (black walnut extract (BWE) and starch gruel models) laminitis. Changes in expression of these enzymes and regulators may underlie the pathologic remodeling of lamellar tissue in laminitis. Genes encoding ADAMs involved in inflammation (ADAM-10 and ADAM-17), as well as those implicated in arthritis (ADAMTS-1, ADAMTS-4 and ADAMTS-5) were cloned, and the sequences used to generate specific oligonucleotide primers for the RT-qPCR experiments. Our results show that genes encoding ADAM-10 and ADAM-17 were not induced in most laminitic animals, whereas ADAMTS-4 gene expression was strongly upregulated in nearly all horses with experimentally-induced and naturally-acquired laminitis. The expression of matrix metalloproteases (MMP)-9 and ADAMTS-5 was also increased in many of the laminitic horses. In addition, TIMP-2 gene expression was decreased in most laminitic horses, whereas expression of genes encoding other TIMPs, namely TIMP-1 and TIMP-3, was randomly increased or decreased in the various models. We conclude that increased expression of lamellar ADAMTS-4 is a common feature of laminitis consistent with a central role of the gene product in the pathophysiology of the disease.

Tissue concentrations of 4-HNE in the black walnut extract model of laminitis: indication of oxidant stress in affected laminae

In the septic horse prone to laminitis, a similar activation of the innate immune system appears to occur as reported in the septic human prone to organ failure. Because oxidant injury plays a central role in organ failure occurring due to an overzealous innate immune response in human sepsis, this study was performed to determine whether there was evidence of oxidant stress in the laminar tissue in the early stages of laminitis. 4-Hydroxy-2-nonenal (4-HNE), a lipid aldehyde that forms due to lipid peroxidation occurring during episodes of oxidant stress, readily forms adducts with cellular proteins; these adducts can be assessed as a marker of oxidant stress in the form of lipid peroxidation. In this study, a slot blot technique was used to assess 4-HNE adduct concentrations in the laminae, lung, liver, and intestinal tract in the black walnut extract (BWE) model of laminitis. Significant increases in laminar 4-HNE adduct concentrations were identified at two early stages in the BWE model, in the absence of such changes in the other tissues. These data indicate that oxidant stress may play an important role in the laminar failure in laminitis, and further support the concept that a poor antioxidant response in the laminae relative to other equine tissues may be responsible for failure of the laminae in the septic horse. In contrast, tissues such as the lung and liver that undergo oxidant injury in human sepsis appear to be relatively protected in horses.

Leukocyte-derived and endogenous matrix metalloproteinases in the lamellae of horses with naturally acquired and experimentally induced laminitis

RATIONALE

Inflammation and dysregulation of endogenous matrix metalloproteinase (MMP) production are implicated in the development of equine laminitis. In this study, we examine quantitative relationships among levels of leukocyte-derived proMMP-9 and MMP-9, lamellar proMMP-2 and MMP-2, and expression of proMMP-2 processing enzymes, MT1-MMP/PACE4, as steps towards determining whether inflammation and dysregulation of endogenous MMP production are independent or co-dependent processes.

ANIMALS

Archived samples of lamellae from horses with naturally acquired laminitis (n = 12), and from horses administered a pro-laminitic gastric bolus of starch gruel were used, the latter horses falling into two groups: (i) responders (CHO-R, n = 7), which developed Obel grade 3-lameness and (ii) non-responders (CHO-NR, n = 4), which did not become lame.

METHODS

Lamellar tissue extracts were analyzed by gelatin zymography to determine gelatinase content and by a myeloperoxidase ELISA to quantify relative monocyte/neutrophil content in the tissue. Real-time PCR was employed to measure gene expression of MT1-MMP and PACE4.

RESULTS AND CONCLUSIONS

Extracts of lamellae from control horses, CHO-NR and horses with chronic (non-aggravated) laminitis had similarly low levels of pro and processed MMP-9 and MMP-2. In contrast, proMMP-9 was significantly elevated in extracts of lamellae from CHO-R and horses with naturally acquired acute and aggravated chronic laminitis. Lamellar MMP-2 was also increased significantly in the CHO-R and aggravated chronic laminitis groups, although not in the horses with naturally acquired acute laminitis. Concentrations of proMMP-9 correlated directly with myeloperoxidase content in lamellar extracts, suggesting production/induction by inflammatory leukocytes. In contrast, concentrations of proMMP-2 and MMP-2 were unrelated to concentrations of myeloperoxidase or proMMP-9 suggesting that leukocyte infiltration and dysregulation of endogenous MMP-2 are independent processes most likely with distinct inducers. Neither MT1-MMP nor PACE4 gene expression was elevated relative to controls in any group; this is discussed with respect to proMMP-2 processing in disease. In addition, variability in relative concentrations of lamellar MMPs observed among horses with Obel grade 3-lameness is discussed in the context of laminitis risk assessment and disease outcome.

Matrix metalloproteinase-9 in laminae of black walnut extract treated horses correlates with neutrophil abundance

We sought to determine whether a correlation exists between neutrophil infiltration and tissue matrix metalloproteinase-9 (MMP-9) content in digital laminae collected during the prodromal and acute phases of laminitis in horses treated with an aqueous black walnut heartwood extract (BWE). Hoof laminar tissue was obtained at the onset of leukopenia and at the onset of clinical signs of lameness from BWE-treated horses and at equivalent times from control horses. Thin sections of laminae were screened for neutrophils by immunohistochemistry with an anti-CD13 monoclonal antibody and extracts of the same tissues were screened for SDS-renaturable and native MMP-9 activities by denaturing and non-denaturing gelatin zymography. Samples were also screened for MMP-2 and MMP-9 gene expression by RT-qPCR. Control laminae were devoid of both MMP-9 and neutrophils, whereas neutrophils and SDS-renaturable MMP-9 activity were detected in laminae from BWE-treated horses and were strongly correlated at the acute stage of the disease at which time laminar MMP-9 gene expression was significantly (15-fold) elevated. In contrast, BWE-treatment did not significantly elevate MMP-2 gene or protein expression in the laminae. Interestingly, MMP-9 that was present in extracts of laminae from BWE-treated horses at both the prodromal and acute stages of the disease was mainly in the zymogen form, suggesting that the accumulation of the MMP did not contribute to pathology during these stages. However, elevated presence of the MMP-9 zymogen in the tissue would predispose it to catastrophic damage should conditions arise that cleave the regulatory propeptide domain.

A comparison of the effects of lamotrigine on neuroma-induced action potential firing and normal behaviour in rat: implications for establishing a pre-clinical 'therapeutic index'

The effects of lamotrigine on rat neuroma and behavioural paradigms were evaluated to determine a pre-clinical therapeutic index. Lamotrigine blocked neuroma-induced burst pattern firing at a free plasma concentration of 13.7+/-1.7 microM (n=5). Oral dosing of lamotrigine (50-200 mg/kg) had no significant effects on behaviour but measurements of plasma concentrations of free drug showed non-linear oral absorption and lower than predicted drug levels (5-27 microM). Given intravenously (10-100 mg/kg), lamotrigine did affect behaviour at a free plasma concentration of 42.0 microM (n=2). By comparing free plasma concentrations, a therapeutic index of 3 was calculated, which is lower than published data based on comparing oral doses. We propose that a therapeutic index should only be derived with reference to plasma drug concentrations to prevent non-linear or incomplete drug absorption from confounding accurate estimation.

Carotid endarterectomy: a comparison of regional versus general anesthesia in 500 operations

The outcomes of 489 patients undergoing 500 carotid endarterectomies were reviewed to compare results from using general anesthesia with those from using regional (cervical block) anesthesia. From September 1982 to May 1998, 228 procedures (221 patients) were performed under general anesthesia and 272 procedures (268 patients) were performed under local anesthesia. A detailed comparison of the two groups revealed close similarity in age, sex, presenting symptoms, and associated risk factors. Overall, perioperative mortality was 0.8%. In comparison to regional anesthesia, the general anesthesia group had greater overall morbidity (23.3 vs. 13. 6%, p < 0.008) and more frequent use of postoperative vasoactive drugs to control blood pressure (40.4 vs. 26.1%, p < 0.001). Furthermore, anesthesia time, operative time, and frequency of shunt use were significantly greater in the general anesthesia group (p < 0.03).

Trends in morbidity and mortality of hepatic resection for malignancy. A matched comparative analysis

OBJECTIVE

The authors define more clearly the trends in morbidity and mortality after hepatic resection for malignant disease in matched patient groups during two discrete time periods.

SUMMARY BACKGROUND DATA

Recent reports have shown improvement in operative morbidity and mortality associated with hepatic resection; however, results often included resections for benign disease and trauma. Furthermore, specific factors contributing to the improvement in operative risks between the last two decades have not been defined.

METHODS

A retrospective matched comparative analysis was conducted of patients with primary and metastatic hepatic malignancy resected with curative intent between two periods (1976 to 1980 and 1986 to 1990). Eighty-one patients met our inclusion criteria in the early period; this group was matched with 81 patients from the latter period by the following four parameters: age, gender, type of malignant disease, and extent of resection. Records of these two patient groups were abstracted for clinical presentation, co-morbid factors, operative techniques, and perioperative morbidity and mortality.

RESULTS

The authors found a significant decrease in operative morbidity, median perioperative transfusion, and length of hospital stay in the latter period (1986 to 1990). The incidence of postoperative subphrenic abscess and intra-abdominal hemorrhage was significantly lower during this period. Operative mortality rate was similar for both periods, 4.9% and 1.2%, respectively (p > 0.05).

CONCLUSION

Hepatic resection for malignant disease currently can be performed with a low morbidity and mortality in the hands of trained and experienced hepatic surgeons; operative risks of hepatic resection should not deter its application in the treatment of primary and metastatic malignant disease of the liver.

Sinistral portal hypertension. Splenectomy or expectant management

Splenectomy has been considered the treatment of choice for patients with bleeding from sinistral portal hypertension (SPH) and varices, but is controversial for asymptomatic patients. To further define the role of splenectomy for SPH, the authors compared the clinical presentations and outcomes of 25 patients treated with splenectomy with those of 12 observed patients. Clinical features were similar except for transfusions administered (60% vs. 25%, p < 0.05), hemoglobin (9.8 +/- 2.2 g/dL vs. 12.5 +/- 2.1 g/dL, p < 0.05), and history of prior bleeding episodes (56% vs. 8%, p < 0.05), splenectomy versus no splenectomy, respectively. At 3 years, neither survival (78% vs. 64%, p = 1.0) nor new or recurrent bleeding (16% vs. 24%, p = 0.2) differed, splenectomy versus no splenectomy, respectively. The authors conclude that in the absence of prior bleeding episodes, anemia, or severe hemorrhage, observation of patients with SPH is justified.

Atrial natriuretic factor inhibits hypertonic saline-mediated decreases in renal hemodynamics

The present study in the anesthetized dogs was designed to test the hypothesis that atrial natriuretic factor (ANF) attenuates whole kidney tubuloglomerular feedback (TGF) mediated decreases in renal blood flow (RBF) and glomerular filtration rate (GFR) produced by hypertonic saline (HS). Secondly, as adenosine (AD) has been implicated as a metabolic mediator of TGF, we also hypothesized that ANF would antagonize the renal actions of AD. To test this hypothesis, RBF and GFR were assessed in response to hypertonic saline (HS, 16%, i.r.) or adenosine (AD, 0.1 mumol/min, i.r.) in the presence and absence of exogenous ANF (100 ng/kg/min, i.r.). ANF attenuated HS-mediated reductions in GFR (HS, -39.6 +/- 9.8 ml/min vs. HS + ANF, -14.3 +/- 4.5 ml/min, P less than 0.05) and in RBF (HS, -143 +/- 35 ml/min vs. HS + ANF, -5 +/- 22 ml/min, P less than 0.05). GFR was reduced by AD (-9.2 +/- 3.0 ml/min, P less than 0.05), but maintained by AD + ANF (-0.4 +/- 2.0 ml/min, NS). A transient adenosine-mediated vasoconstriction was attenuated by ANF (AD, -54.5 +/- 3.6 ml/min vs. AD + ANF, -3.7 +/- 3.1 ml/min, P less than 0.005). We conclude that ANF at pharmacologic concentrations attenuates at the whole kidney level hypertonic saline and adenosine-mediated reductions in RBF and GFR.

Space: exploration-exploitation and the role of man

The early years of space activity have emphasized a crew role similar to that of the test pilot or the crew of a high performance aircraft; even the Apollo lunar exploration missions were dominated by the task of getting to and from the moon. Skylab was a prototype space station and began to indicate the range of other functional roles man will play in space. The operation of the Space Shuttle has the elements of the operation of any other high performance flight vehicle during launch and landing; but in its on-orbit operations, it is often a surrogate space station, developing techniques and demonstrating the role of a future space station in various functions. In future space systems, the role of the crew will encompass all of the activities pursued in research laboratories, manufacturing facilities, maintenance shops, and construction sites. The challenge will be to design the tasks and the tools so that the full benefit of the opportunities offered by performing these functions in space can be attained.