Canine Cerebrospinal Fluid Research Articles

Accuracy of urinary dipstick for glucose and protein determination in canine cerebrospinal fluid.

To evaluate the precision of urinary dipstick (UD) to assess protein and glucose concentrations in canine CSF samples compared to the standard methods. Cerebrospinal fluid protein and glucose were measured in 22 samples from dogs with neurological diseases affecting the CNS using UD and biochemistry (pyrogallol red and glucose oxidase reaction, respectively). Results were converted into scores to allow comparison between methods. The proportion of divergence between methods and its CI were calculated. The sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and accuracy (Ac) of UD were determined for 2 cutoff levels of CSF protein (15 and 30 mg/dL) and glucose (40 and 100 mg/dL). The proportion of divergence between methods was 64% (95% CI, 44% to 84%) for CSF protein (representing 14 of 22 erroneous samples), of which 92.9% (13 of 14) had a UD score lower than biochemistry. For CSF glucose, 73% (16 of 22 erroneous samples; 95% CI, 54% to 91%) had divergence between methods, of which 87.5% (14 of 16) had a UD score higher than biochemistry. Urinary dipstick had better results when the cutoff level was 15 mg/dL for protein (Se, 78.9%; Sp, 66.7%; PPV, 93.7%; NPV, 33.3%; Ac, 77.3%) and 40 mg/dL for glucose (Se, 89.5%; Sp, 33.3%; PPV, 89.5%; NPV, 33.3%; Ac, 81.8%) concentrations. Urinary dipstick was unreliable in estimating canine CSF protein and glucose concentrations. The UD underestimated protein and overestimated glucose levels in the canine CSF, which could have a significant diagnostic impact and should discourage its use as a bedside test.

Canine Cerebrospinal Fluid Analysis Using Two New Automated Techniques: The Sysmex XN-V Body Fluid Mode and an Artificial-Intelligence-Based Algorithm.

Cerebrospinal fluid analysis is an important diagnostic test when assessing a neurological canine patient. For this analysis, the total nucleated cell count and differential cell counts are routinely taken, but both involve time-consuming manual methods. To investigate faster automated methods, in this study, the Sysmex XN-V body fluid mode and the deep-learning-based algorithm generated by the Olympus VS200 slide scanner were compared with the manual methods in 161 canine cerebrospinal fluid samples for the total nucleated cell count and in 65 samples with pleocytosis for the differential counts. Following incorrect gating by the Sysmex body fluid mode, all samples were reanalyzed with manually set gates. The Sysmex body fluid mode then showed a mean bias of 15.19 cells/μL for the total nucleated cell count and mean biases of 4.95% and -4.95% for the two-part differential cell count, while the deep-learning-based algorithm showed mean biases of -7.25%, -0.03% and 7.27% for the lymphocytes, neutrophils and monocytoid cells, respectively. Based on our findings, we propose that the automated Sysmex body fluid mode be used to measure the total nucleated cell count in canine cerebrospinal fluid samples after making adjustments to the predefined settings from the manufacturer. However, the two-part differential count of the Sysmex body fluid mode and the deep-learning-based algorithm require some optimization.

Creatine kinase and its isoenzymes in the serum and cerebrospinal fluid of healthy canines.

Creatine kinase (CK) exists as three isoenzymes (CK-MM, CK-MB, and CK-BB) that are predominantly expressed in specific tissues and can be detected in both the serum and cerebrospinal fluid (CSF). CSF CK has been relatively unstudied in veterinary medicine, although studies in human medicine have demonstrated that changes in total CSF CK activity can indicate neurologic abnormalities. The purpose of this study was to establish reference intervals for CK and its three major isoenzymes in the serum and CSF of clinically healthy dogs. By establishing a definitive reference interval for this enzyme in healthy canines, the diagnostic use and possible significance of CK in clinical disease can be studied. Serum and/or CSF were collected from healthy dogs. Total CK activity was measured spectrophotometrically, and isoenzyme distributions were determined using the QuickGel CK Vis Isoenzyme Kit and a densitometric scanner. Total CK and CK isoenzyme activities were determined within 8 h of collection. The median serum total CK in healthy canines was 159.0 U/L (range: 53.0-539.0 U/L), while the median CSF total CK was 3.7 U/L (range: 2.0-84.0 U/L). CK-BB and CK-MM were approximately equal in the serum, while CK-MM was the predominant isoenzyme in the CSF. Knowledge of the normal distribution and concentration of CK in canine serum and CSF will set the foundation for future studies of canine CK as a potentially clinically useful biomarker.

Evaluation of a Manual Cytocentrifuge versus the Standard Automated Cytocentrifuge in the Analysis of Canine Cerebrospinal Fluid: A Case Series of 55 Dogs.

Cytospins are important for evaluating fluids with very low cellularity such as cerebrospinal fluid (CSF). The aim of this study was to compare the CSF cytospin preparations obtained from automated and manual cytocentrifugation methods. A prospective case series was performed to analyze canine CSF samples using both centrifugation methods. The cytospins were processed within 30-60 min and prepared simultaneously in a conventional automated cytocentrifuge and in an in-house manual cytocentrifuge, using a fixed volume of CSF fluid. The cellularity, differential cell count and the proportion of cell artifacts (pseudopods and vacuolization) were blindly assessed in the cytospin preparations obtained using the two methods. The agreement and correlation between both methods were analyzed. There were 55 dogs enrolled (48 prospectively and 7 retrospectively) in the study. 38 dogs had normal total nucleated cell counts, while 17 had pleocytosis. Automated and manual cytocentrifugation had similar cell yields, and no significant differences in differential cell counts or the presence of artifacts existed between both methods. In cases with pleocytosis, the cytologic diagnosis obtained using each method was similar. Manual cytocentrifugation of CSF is a reliable and economic method designed for routine clinical practice. Its use reduces the specimen deterioration related to processing and analysis delays when samples are transported to external laboratories for evaluation.

Towards optimised extracellular vesicle proteomics from cerebrospinal fluid

The proteomic profile of extracellular vesicles (EVs) from cerebrospinal fluid (CSF) can reveal novel biomarkers for diseases of the brain. Here, we validate an ultrafiltration combined with size-exclusion chromatography (UF-SEC) method for isolation of EVs from canine CSF and probe the effect of starting volume on the EV proteomics profile. First, we performed a literature review of CSF EV articles to define the current state of art, discovering a need for basic characterisation of CSF EVs. Secondly, we isolated EVs from CSF by UF-SEC and characterised the SEC fractions by protein amount, particle count, transmission electron microscopy, and immunoblotting. Data are presented as mean ± standard deviation. Using proteomics, SEC fractions 3–5 were compared and enrichment of EV markers in fraction 3 was detected, whereas fractions 4–5 contained more apolipoproteins. Lastly, we compared starting volumes of pooled CSF (6 ml, 3 ml, 1 ml, and 0.5 ml) to evaluate the effect on the proteomic profile. Even with a 0.5 ml starting volume, 743 ± 77 or 345 ± 88 proteins were identified depending on whether ‘matches between runs’ was active in MaxQuant. The results confirm that UF-SEC effectively isolates CSF EVs and that EV proteomic analysis can be performed from 0.5 ml of canine CSF.

Determination of the effect of iatrogenic blood contamination on lactate dehydrogenase and creatine kinase activity in canine cerebrospinal fluid.

Lactate dehydrogenase (LDH) and creatine kinase (CK) have differential tissue activity and isoenzyme profiles. LDH and CK exist as 5 and 3 isoenzymes, respectively, in both serum and cerebrospinal fluid (CSF). Studies have demonstrated that measuring LDH, CK, and their isoenzymes in CSF has diagnostic and prognostic values for dogs and people with neurologic disorders. Iatrogenic blood contamination can distort the results of CSF analysis. The purpose of this study was to determine allowable thresholds of blood contamination (RBC/μL) for accurate measurement of LDH, CK, and their isoenzymes in canine CSF. Venous blood and CSF were collected from healthy dogs. Total LDH and CK activity were measured spectrophotometrically. Isoenzyme profiles were determined using gel electrophoresis and densitometric scanning. All samples were analyzed within 6hours of collection. A nonlinear mixed effects regression model was used to estimate the allowable thresholds of blood contamination for accurate measurement of LDH, CK, and their isoenzymes in canine CSF. The threshold of iatrogenic blood contamination for total LDH and total CK in healthy dogs are 6696 RBC/μL (95% CI 3879-11 187) and 5961 RBC/μL (95% CI 2939-12 085), respectively. LDH-1 is the most sensitive isoenzyme to iatrogenic blood contamination, while LDH-4 is the least sensitive. These results are important for the interpretation of LDH, CK, and their isoenzymes in canine CSF. Additionally, our methodology is translatable for determining thresholds of acceptable iatrogenic blood contamination in CSF for other diagnostic and prognostic biomarkers of neurologic disease.

Performance of the Sysmex XN‐V body fluid module for canine cerebrospinal fluid cell count

Microscopic cell counts and nucleated cell identification are the "gold standard" for cerebrospinal fluid (CSF) assessments and are labor intensive and subject to operator variability. The use of automated methods could be an alternative to the current manual technique. We aimed to assess the utility of the Sysmex XN-V body fluid (BF) module analyzer to count and differentiate nucleated cells in canine CSF and evaluate the accuracy and correlation between this and the manual method. We prospectively analyzed 150 CSF samples from dogs using the Sysmex XN-V BF module and compared the results with those obtained using the manual counting method. We also evaluated the linearity, detection limits, and imprecision of the Sysmex XN-V BF module. The Sysmex XN-V BF module analyzer performance had a sensitivity of 92.59% and specificity of 94.30%. The lower limit of quantification for the total nucleated cell count (TNCC) was 0cells/μL. A Pearson´s correlation coefficient of 0.945 was found between both methods for TNCC, with 0.997 and 0.940 for samples with TNCC >10cells/μL and TNCC >5cells/μL, respectively. The correlation coefficient for the mononuclear and polymorphonuclear differential cell count was -0.031 and -0.019, respectively, and it was 0.576 for the RBC count. The Sysmex XN-V BF module provides reliable TNCCs for canine CSF, even for samples with low cell numbers, but manual cytologic evaluation is still needed for differential cell counts.

Diagnostic utility of canine cerebrospinal fluid preserved by 10% buffered formalin.

To examine the diagnostic utility of canine cerebrospinal fluid samples collected into tubes containing ethylenediaminetetraacetic acid (EDTA) with and without the addition of 10% buffered formalin analysed within 6 to 20 hours. Inclusion criteria were dogs presenting to a referral hospital with neurological signs and having cerebrospinal fluid analysis performed. Samples were submitted to an external laboratory in tubes containing ethylenediaminetetraacetic acid as paired-samples; one with the addition of one drop of 10% buffered formalin and the other without formalin. Cytology report, total nucleated cell counts, and protein concentration were reviewed. Three different categories of cell preservation were defined: diagnostic, non-diagnostic and unclassified. Each sample was included in one of these categories depending on cytological features, and the diagnostic quality between samples was compared. Samples were further divided in two groups depending on protein concentration using 50 mg/dL as cut-off value and the diagnostic quality between samples was compared. 254 samples from 127 dogs were included. 47% of samples without formalin were non-diagnostic, 46% diagnostic and 6% unclassified. In the formalin group, 2% samples were non-diagnostic, 92% diagnostic and 6% unclassified. Samples with formalin preservation were statistically more likely to be diagnostic than samples without formalin preservation. In both protein groups (≥50 and <50 mg/dL) formalin samples were statistically more likely to be diagnostic as well. The addition of one drop of 10% formalin is a simple, widely available method which can help to improve the accuracy of cytological assessment in canine cerebrospinal fluid by preserving cellular morphology when analysis is performed within 6 to 20 hours.

Stability of canine and feline cerebrospinal fluid samples regarding total cell count and cell populations stored in \u201cTransFix\xae/EDTA CSF sample storage tubes\u201d

BackgroundBecause of fast leucocyte degeneration in cerebrospinal fluid (CSF) laboratory examinations of CSF samples should be performed approximately within 30 min after withdrawal. This study examines the storage of canine and feline CSF samples in “TransFix®/EDTA CSF Sample Storage Tubes” (Cytomark, Buckingham, UK) for preventing leucocytes from degeneration, so that routine and flow cytometry examinations are feasible up to 3 days after sampling.ResultsAfter storage in TransFix® tubes, leukocytes could not be adequately stained with Türk’s solution and differentiating between erythrocytes and leukocytes was cumbersome. In addition, the cell morphology could not be sufficiently assessed on cytospin preparations because of shrunken leukocytes and indistinct cell nuclei. In contrast, by flow cytometry, a significantly higher cell count was measured over the entire study period in the samples stored in TransFix® tubes compared to the untreated samples. The antibodies (AB) against CD3, CD4 and CD21, against CD11b and against CD45 showed a good binding strength and thus enabled a good differentiation of cell populations. However, after storage in the TransFix® tubes, monocytes were no longer detectable using an AB against CD14.ConclusionBased on these results, “TransFix®/EDTA CSF Sample Storage Tubes” can be used for extended storage prior to flow cytometric analysis of lymphocytes and granulocytes in CSF samples but not for detecting monocytes. However, standard examinations, such as microscopic cell counting and morphological cell assessment should be performed on fresh CSF samples.

Ehrlichia canis infection in the cerebrospinal fluid of a dog characterized by morulae within monocytes and neutrophils

An 8-year-old neutered female English Pointer was referred to a veterinary referral center (southwest of England) with a 4-5-month history of fecal incontinence and no evidence of urinary incontinence. Blood and free-catch urine samples were collected and sent to an off-site laboratory. Further investigations were postponed until laboratory results were available. Blood results showed a mild leukopenia, mild nonregenerative anemia, moderate to marked thrombocytopenia, and a mild increase in ALT and ALP activities. The primary veterinarian and client did not proceed with any further investigations for thrombocytopenia. Three weeks after the initial presentation, there was considerable clinical deterioration and progression of neurologic signs. Thoracic radiographs and an abdominal ultrasonographic examination were unremarkable. Magnetic resonance imaging (MRI) of the brain and spinal cord revealed an intramedullary lesion at the level of the C7 vertebra, a cystic lesion in the forebrain, and a bilateral lesion in the thalamus. A lumbar cerebrospinal fluid (CSF) was collected. CSF analysis showed a robustly increased protein concentration and marked pleocytosis. The cytologic evaluation revealed a mixed cellular population. Occasional neutrophils and monocytoid cells showed purple spherical intracellular inclusions, resembling Ehrlichia morulae. An aliquot of CSF was used off-label with a dot ELISA test, which showed a strong positive result for antibodies against Ehrlichia canis/Ehrlichia ewingii. PCR identified these morulae to be E canis. To best of the authors' knowledge, this is the first case of ehrlichial infection in canine CSF where Ehrlichia sub-species morulae present within neutrophils were confirmed to be Ehrlichia canis using PCR.

Evaluation of the hydroxyethyl starch stabilizing agent, Vetstarch, in the preservation of canine cerebrospinal fluid samples

A challenge of cerebrospinal fluid (CSF) analysis is the time-dependent degradation of nucleated cells, impeding accurate interpretation. CSF additives have been used to delay cell degradation; however, stabilizing agents, including serum, can alter microprotein levels. This study aimed to determine if the hydroxyethyl starch, Vetstarch, is effective at preserving nucleated cell morphology in CSF compared with the saline diluent or serum without altering microprotein levels. CSF samples were collected from 26 dogs. Samples were divided into four aliquots. One aliquot was analyzed immediately (control). The remaining three aliquots were mixed with either saline, fetal calf serum, or Vetstarch before storage at 4°C. Nucleated cell differentials, protein concentrations, and cell morphology scores were analyzed 48hours later. A cell morphology score of 1 indicated no cellular degeneration; a score of 4 indicated severe degeneration. Samples stored in serum, saline, and Vetstarch exhibited poorer mean (±SD) morphology scores (2.4±0.7, 2.6±0.8, and 2.7±0.9, respectively) compared with controls (1.9±0.4). Samples stored in saline and Vetstarch demonstrated higher percentages of unrecognizable cells, with a median of 28 (range 0-100) and 27 (0-100), respectively; samples stored in serum had a median of 14 (range 0-67) unrecognizable. Microprotein levels of samples stored in Vetstarch were dependent on the method of protein analysis. Serum significantly increased microprotein levels. Vetstarch does not reduce time-dependent cellular degeneration compared with the saline diluent or serum and is, therefore, not recommended as a stabilizing agent for canine cerebrospinal fluid.

Proper fraction of inspired oxygen for reduction of oxygen-induced canine cerebrospinal fluid hyperintensity on fluid attenuation inversion recovery sequence using low-field magnetic resonance imaging.

Oxygen-induced cerebrospinal fluid (CSF) hyperintensity artifact is inevitable in fluid attenuation inversion recovery (FLAIR) magnetic resonance (MR) images of anesthetized animals. This experimental study aimed to confirm the occurrence of this artifact on low-field magnetic resonance imaging (MRI), and to determine the fraction of inspired oxygen (FiO2) that is safe and does not induce this artifact in canine brain MRI. Six healthy dogs underwent brain FLAIR MR scans under general anesthesia with 21%, 30%, 50%, 70%, and 100% FiO2. The signal intensity (SI) ratio was calculated as the SI of CSF spaces divided by that of normalizing regions. The SI ratios of 21% FiO2 images were significantly different from those of 100% FiO2 images, indicating the presence of artifacts on 100% FiO2 images. The SI ratios of 30% FiO2 images were not significantly different from those of 21% FiO2 images for any of CSF spaces. However, they were significantly different from those of 100% FiO2 images in the cerebral sulci, third ventricle, interpeduncular cistern, mesencephalic aqueduct, and subarachnoid space at the level of the first cervical vertebra (P<0.05). All dogs had normal partial pressure of arterial oxygen (PaO2) during inhalation of 30% FiO2, while two dogs had low PaO2 during inhalation of 21% FiO2. Our findings support the hypothesis that high FiO2 induces CSF hyperintensity artifact on low-field FLAIR MR images in dogs. FiO2 of 30% is appropriate for obtaining brain FLAIR MR images with fewer artifacts in dogs.

Evaluation of the Idexx ProCyte Dx® for analysis of canine cerebrospinal fluid.

To assess the utility of the Idexx ProCyte Dx® haematology analyser for assessing total nucleated cell count and differential cell counts in canine cerebrospinal fluid. Seventy-three client-owned dogs undergoing investigations for pyrexia and/or neurological signs were prospectively included. Cerebrospinal fluid samples were assessed using an Idexx ProCyte Dx® analyser and the results were compared to those obtained with the external laboratory reference standard. The Idexx ProCyte Dx® performed with good sensitivity (92.6%) and moderate specificity (67.4%) for total nucleated cell count when compared to the reference standard. Qualitative assessment of the Idexx ProCyte Dx® scatter plots, and quantitative assessment of differential cell counts where available, appeared to correlate well with the external laboratory manual differential cell counts, with a good-to-high agreement in 25 of 26 samples (96.2%). The Idexx ProCyte Dx® analyser performed well in determining the total nucleated cell count and differential cell counts in canine cerebrospinal fluid when compared to a reference standard of external laboratory analysis, except for cell counts higher than ~1000/μL. As the Idexx ProCyte Dx® currently only provides a cell count in 10 cells/μL increments, software modification may improve agreement between the two methods. As in human medicine, automated methods may prove useful in the future for cerebrospinal fluid analysis in addition to manual assessment, particularly in an emergency setting.

MicroRNA expression in the cerebrospinal fluid of dogs with and without cervical spondylomyelopathy.

BackgroundOsseous‐associated cervical spondylomyelopathy (OA‐CSM) is a common condition of the cervical vertebral column that affects giant dog breeds. MicroRNAs (miRNAs) are small RNAs that regulate gene expression, and recent data suggest that circulating miRNAs present in biological fluids may serve as potential biomarkers for disease. The miRNA profiles of cerebrospinal fluid (CSF) from healthy dogs and dogs clinically affected by OA‐CSM have not been described.ObjectiveTo characterize the expression levels of miRNAs present in the CSF of normal Great Danes and identify differentially expressed miRNAs in the CSF of Great Danes clinically affected with OA‐CSM.AnimalsClient‐owned dogs: 12 control, 12 OA‐CSM affected.MethodsCerebrospinal fluid samples were collected prospectively. MicroRNA expression was evaluated using the NanoString nCounter platform and quantitative real‐time PCR.ResultsWe identified 8 miRNAs with significant differential expression. MiR‐299‐5p and miR‐765 had increased expression levels in the CSF of OA‐CSM‐affected dogs, whereas miR‐494, miR‐612, miR‐302‐d, miR‐4531, miR‐4455, and miR‐6721‐5p had decreased expression levels in OA‐CSM affected dogs compared to clinically normal dogs. Quantitative real‐time PCR was performed to validate the expression levels of 2 miRNAs (miR‐494 and miR‐612), and we found a 1.5‐fold increase in miR‐494 expression and a 1.2‐fold decrease in miR‐612 in the CSF of the OA‐CSM affected group (P = .41 and .89, respectively).Conclusions and Clinical ImportanceData generated from our study represent an initial characterization of the miRNA profile of normal canine CSF and suggest that a distinct CSF miRNA expression profile is associated with OA‐CSM.

Measurement of Neutrophil Gelatinase-Associated Lipocalin Concentration in Canine Cerebrospinal Fluid and Serum and Its Involvement in Neuroinflammation.

Neutrophil gelatinase-associated Lipocalin (NGAL) is a glycoprotein involved in inflammation acting as an acute phase protein and chemokine as well as a regulator of iron homeostasis. NGAL has been shown to be upregulated in experimental autoimmune encephalomyelitis (EAE) in mice. Increased NGAL concentration in cerebrospinal fluid (CSF) and expression in central nervous system (CNS) has been described in human neuroinflammatory disease such as multiple sclerosis and neuropsychiatric lupus as well as in bacterial meningitis. We aimed to investigate involvement of NGAL in spontaneous canine neuroinflammation as a potential large animal model for immune- mediated neurological disorders. A commercially available Enzyme-linked Immunosorbent Assay (ELISA) for detection of canine NGAL was validated for use in canine CSF. Concentration in CSF and serum of canine patients suffering from steroid- responsive meningitis- arteriitis (SRMA), Meningoencephalitis of unknown origin (MUO), different non- inflammatory CNS disease and control dogs were compared. Relationship between NGAL concentration in CSF and serum and inflammatory parameters in CSF and blood (IgA concentration, total nucleated cell count (TNCC), protein content) as well as association with erythrocytes in CSF, duration of illness, plasma creatinine and urinary leucocytes were evaluated. In dogs with SRMA and MUO, CSF concentration of NGAL was significantly higher than in dogs with idiopathic epilepsy, compressive myelopathy, intracranial neoplasia and SRMA in remission (p < 0.0001). Patients with acute SRMA had significantly higher levels of NGAL in CSF than neurologically normal controls (p < 0.0001). Serum NGAL concentrations were significantly higher in dogs with SRMA than in patients with myelopathy and intracranial neoplasia (p < 0.0001). NGAL levels in CSF were strongly positively associated with IgA concentration (rSpear= 0.60116, p < 0.0001), TNCC (rSpear= 0.65746, p < 0.0001) and protein content (rSpear= 0.73353, p < 0.0001) in CSF. It can be measured in CSF of healthy and diseased dogs. Higher concentrations in canine patients with SRMA as well as positive association with TNCC in CSF suggest an involvement in pro-inflammatory pathways and chemotaxis in SRMA. High serum levels of NGAL in serum of SRMA patients in different stages of disease might reflect the systemic character of the disease.

Detection of Intraspinal Spirocerca lupi in Canine Cerebrospinal Fluid by Polymerase Chain Reaction

Aberrant migration of Spirocerca lupi into the spinal cord is an important cause of severe progressive neurological dysfunction in dogs. Although early diagnosis is essential to prevent deterioration, ante-mortem diagnosis of this condition remains challenging. The aim of this study was to evaluate the detection of the 18S ribosomal DNA (rDNA) S. lupi gene in the cerebrospinal fluid (CSF) of presumptively-affected dogs using polymerase chain reaction (PCR). Dogs with a non-compressive spinal cord lesion, pleocytosis with presence of eosinophils in the CSF and a characteristic clinical presentation were included. CSF samples from eight dogs were available for the study, of which seven were definitively diagnosed with intraspinal spirocercosis by PCR of either the CSF samples (6/7) or tissue samples obtained at necropsy examination (3/7), or both (2/7). Of these seven positive cases, only one dog had a negative CSF PCR, indicating a sensitivity of 86% for detecting nematode DNA in the CSF of infected dogs using this PCR protocol. The nematode DNA sequences obtained from the CSF of six dogs and the spinal cord tissue of three dogs were 98-100% identical to the publicly available sequences of S. lupi, confirming the diagnosis. These findings indicate that PCR targeting the 18S rDNA of S. lupi in CSF is useful for the ante-mortem diagnosis of canine intraspinal spirocercosis.

The effects of iatrogenic blood contamination on total nucleated cell counts and protein concentrations in canine cerebrospinal fluid

Cerebrospinal fluid (CSF) might be altered by iatrogenic blood contamination, precluding accurate diagnostic interpretation. Available formulas to correct for iatrogenic blood contamination are likely unreliable. Study objectives were to determine the effects of blood contamination on total nucleated cell counts (NCCs) and protein concentrations in canine CSF. Two methods were followed to evaluate the effect of blood contamination on total NCC and protein concentrations in CSF. First, records from the Colorado State University Veterinary Teaching Hospital were retrospectively searched for dogs where CSF analysis was performed. Total NCCs, RBC counts, protein concentrations, and cytologic interpretations were recorded. Second, CSF from 4 canine patients and 3 research hounds was prospectively analyzed before and after known dilutions of whole blood were added. Of the 787 clinical samples analyzed, 108 samples had a cytologic diagnosis of blood contamination. RBC counts for all clinical samples ranged from 0 to 210,000 cells/μL. No correlation between total NCCs or protein concentrations with RBC counts were found when all samples were evaluated. Total NCCs and RBCs were weakly correlated in samples with a cytologic diagnosis of blood contamination and when ≥500 RBC/μL was present. When serial dilutions of whole blood were added to normal CSF, no significant changes were observed in the total NCCsof uncontaminated aliquots and contaminated aliquots containing up to 8480 RBC/μL. Erythrocyte counts in blood-contaminated canine CSF poorly correlate with total NCCs and protein concentrations. Using formulas to correct total NCCs and protein concentrations for the number of RBCs in CSF is inappropriate.

Reference intervals for the activity of lactate dehydrogenase and its isoenzymes in the serum and cerebrospinal fluid of healthy canines

Lactate dehydrogenase (LD) exists as 5 isoenzymes (LD-1 through LD-5) that are expressed throughout the body and can be detected in both serum and cerebrospinal fluid (CSF). LD and its isoenzymes have been relatively unstudied in veterinary medicine, although studies in human medicine have demonstrated that changes in total LD activity and atypical isoenzyme patterns can indicate disease processes, including neurologic abnormalities. The purpose of this study was to establish RIs for LD and its isoenzymes in the serum and CSF of clinically healthy dogs. By establishing a definitive RI for this enzyme in healthy canines, further study of the clinical and diagnostic usefulness of LD can be undertaken. Serum and atlantoaxial CSF were collected from clinically healthy dogs. Total LD activity was measured spectrophotometrically immediately after collection. Isoenzyme distributions were also determined within 8hours of collection using the QuickGel LD Isoenzyme technique and a densitometric scanner. The median serum total LD in healthy canines was 69.0 U/L (n=41; range: 21.0-217.0U/L), while the median CSF total LD was 10.0 U/L (n=40; range: 6.0-19.3U/L). LD-5 is the predominant isoenzyme in canine serum (n=40), contributing over half of the total enzyme activity. Conversely, in canine CSF (n=42), LD-1 is the predominant isoenzyme, followed by LD-2 and LD-3. Knowledge of the distribution and concentration of LD in the serum and CSF of healthy dogs will set the foundation for future studies of canine LD as a potentially clinically useful biomarker.

Development of an electrochemiluminescent assay to measure LAMP2 in canine cerebrospinal fluid samples

Development of an electrochemiluminescent assay to measure LAMP2 in canine cerebrospinal fluid samples

Evaluation of the effect of oral omeprazole on canine cerebrospinal fluid production: A pilot study

Administration of omeprazole by ventriculo-cisternal perfusion or intravenously has been shown to decrease cerebrospinal fluid (CSF) production in dogs and rabbits. Oral omeprazole has consequently been recommended to reduce CSF production in dogs with conditions in which clinical signs may be attributable to an accumulation of CSF in the central nervous system (e.g. hydrocephalus, syringomyelia). The albumin quotient (QAlb), the ratio between CSF and serum albumin concentration, has been proposed as a reliable means to evaluate CSF production; decreasing CSF production should cause an increase in QAlb.The aims of this study were to assess the effect of oral administration of omeprazole on QAlb in dogs and to compare two methods to assess CSF albumin concentration. Fifteen healthy Beagle dogs received omeprazole (1.2 mg/kg/day) orally for 14 days; CSF and blood were obtained before and after treatment. CSF albumin concentrations were evaluated by nephelometry and high-resolution protein electrophoresis. Regardless of the method used for measuring albumin, QAlb did not change significantly following oral omeprazole administration, suggesting that CSF production in healthy dogs may not be affected by chronic oral therapy with omeprazole.