Central Nervous System Of Dogs Research Articles

A multiplex quantitative real-time polymerase chain reaction panel for detecting neurologic pathogens in dogs with meningoencephalitis.

Meningoencephalitis (ME) is a common inflammatory disorder of the central nervous system in dogs. Clinically, ME has both infectious and non-infectious causes. In the present study, a multiplex quantitative real-time polymerase chain reaction (mqPCR) panel was optimized for the detection of eight canine neurologic pathogens (Blastomyces dermatitidis, Cryptococcus spp., Neospora caninum, Borrelia burgdorferi, Bartonella spp., Toxoplasma gondii, Ehrlichia canis, and canine distemper virus [CDV]). The mqPCR panel was subsequently applied to 53 cerebrospinal fluid (CSF) samples collected from dogs with ME. The analytic sensitivity (i.e., limit of detection, expressed as molecules per 1 µL of recombinant vector) was 3.8 for CDV, 3.7 for Ehrlichia canis, 3.7 for Bartonella spp., 3.8 for Borrelia burgdorferi, 3.7 for Blastomyces dermatitidis, 3.7 for Cryptococcus spp., 38 for Neospora caninum, and 3.7 for Toxoplasma gondii. Among the tested CSF samples, seven (15%) were positive for the following pathogens in decreasing order of frequency: Cryptococcus spp. (3/7), Blastomyces dermatitidis (2/7), and Borrelia burgdorferi (2/7). In summary, use of an mqPCR panel with high analytic sensitivity as an initial screen for infectious agents in dogs with ME could facilitate the selection of early treatment strategies and improve outcomes.

Flavonoids Modulate the Proliferation of Neospora caninum in Glial Cell Primary Cultures

Neospora caninum (Apicomplexa; Sarcocystidae) is a protozoan that causes abortion in cattle, horses, sheep, and dogs as well as neurological and dermatological diseases in dogs. In the central nervous system of dogs infected with N. caninum, cysts were detected that exhibited gliosis and meningitis. Flavonoids are polyphenolic compounds that exhibit antibacterial, antiparasitic, antifungal, and antiviral properties. In this study, we investigated the effects of flavonoids in a well-established in vitro model of N. caninum infection in glial cell cultures. Glial cells were treated individually with 10 different flavonoids, and a subset of cultures was also infected with the NC-1 strain of N. caninum. All of the flavonoids tested induced an increase in the metabolism of glial cells and many of them increased nitrite levels in cultures infected with NC-1 compared to controls and uninfected cultures. Among the flavonoids tested, 3',4'-dihydroxyflavone, 3',4',5,7-tetrahydroxyflavone (luteolin), and 3,3',4',5,6-pentahydroxyflavone (quercetin), also inhibited parasitophorous vacuole formation. Taken together, our findings show that flavonoids modulate glial cell responses, increase NO secretion, and interfere with N. caninum infection and proliferation.

Non-infectious inflammatory diseases of the central nervous system in dogs

Inflammatory diseases of the central nervous system (CNS) present as progressive diseases, often with a collection of neurological deficits reflecting multifocal involvement of the CNS. The most common signalment (middle-aged small-breed dogs, more commonly females) can provide a high index of suspicion, combined with neurological findings, CSF analysis and imaging studies. The prognosis is guarded, and some dogs will deteriorate rapidly despite therapy, while others can live for years with or without medication, which reflects currently our lack of understanding of this group of diseases.

Broadly Reactive Polymerase Chain Reaction for Pathogen Detection in Canine Granulomatous Meningoencephalomyelitis and Necrotizing Meningoencephalitis

BackgroundGranulomatous meningoencephalomyelitis (GME) and necrotizing meningoencephalitis (NME) are common inflammatory conditions of the central nervous system of dogs. Infectious pathogens, particularly viruses, are suspected to contribute to the etiopathogenesis of GME and NME.HypothesisBroadly reactive PCR might aid in the identification of infectious agents in GME and NME.AnimalsSixty‐eight client‐owned dogs evaluated by necropsy at 1 university referral hospital.MethodsA mixed prospective/retrospective case‐control study was performed. Brain tissue prospectively collected at necropsy from GME, NME, and control cases was evaluated by broadly reactive polymerase chain reaction (PCR) for adenoviruses, bunyaviruses, coronaviruses, enteroviruses, flaviviruses, herpesviruses, paramyxoviruses, and parechoviruses. In addition, these tissues were retrospectively evaluated for the presence of mycoplasmas by PCR, culture, and immunohistochemistry (IHC).ResultsBrain tissue was collected from 11 GME and 27 NME cases and 30 controls. Viral nucleic acids were not identified in the 6 GME cases, 25 NME cases, and 2 controls evaluated by viral PCR. Mycoplasma canis was identified by Mycoplasma genus PCR in 1/5 GME and 4/25 NME cases and subsequently was cultured from 4/5 GME and 4/8 NME cases as well as 2/9 controls. The IHC did not detect M. canis in any of the 11 GME and 27 NME cases or 14 controls evaluated with strain PG14 polyclonal antiserum.Conclusions and Clinical ImportanceThe negative results suggest that viral pathogens are not common in the brain tissue of dogs with GME and NME. Further investigation is warranted to determine the importance of M. canis in cases of GME and NME.

Circulating insulin stimulates fatty acid retention in white adipose tissue via KATP channel activation in the central nervous system only in insulin-sensitive mice

Insulin signaling in the central nervous system (CNS) is required for the inhibitory effect of insulin on glucose production. Our aim was to determine whether the CNS is also involved in the stimulatory effect of circulating insulin on the tissue-specific retention of fatty acid (FA) from plasma. In wild-type mice, hyperinsulinemic-euglycemic clamp conditions stimulated the retention of both plasma triglyceride-derived FA and plasma albumin-bound FA in the various white adipose tissues (WAT) but not in other tissues, including brown adipose tissue (BAT). Intracerebroventricular (ICV) administration of insulin induced a similar pattern of tissue-specific FA partitioning. This effect of ICV insulin administration was not associated with activation of the insulin signaling pathway in adipose tissue. ICV administration of tolbutamide, a K(ATP) channel blocker, considerably reduced (during hyperinsulinemic-euglycemic clamp conditions) and even completely blocked (during ICV administration of insulin) WAT-specific retention of FA from plasma. This central effect of insulin was absent in CD36-deficient mice, indicating that CD36 is the predominant FA transporter in insulin-stimulated FA retention by WAT. In diet-induced insulin-resistant mice, these stimulating effects of insulin (circulating or ICV administered) on FA retention in WAT were lost. In conclusion, in insulin-sensitive mice, circulating insulin stimulates tissue-specific partitioning of plasma-derived FA in WAT in part through activation of K(ATP) channels in the CNS. Apparently, circulating insulin stimulates fatty acid uptake in WAT but not in BAT, directly and indirectly through the CNS.

Levels of matrix metalloproteinase-2 and metalloproteinase-9 in the cerebrospinal fluid of dogs with visceral leishmaniasis

Inflammation causes increases in the level of matrix metalloproteinases (MMPs), which, in central nervous system (CNS), are associated with neuroinflammation and disruption of blood-brain barrier. Analysis of cerebrospinal fluid (CSF) is pivotal for detecting diseases in CNS and, although a specific diagnosis may not be achieved, this analysis is helpful to confirm the diagnosis or to rule out relevant differential diagnoses. This study examined the levels of MMP-2 and MMP-9 in the CSF of dogs using gelatin zymography to verify possible alterations in these enzymes during natural systemic infection with Leishmania chagasi. Latent and active forms of MMP-2 were detected in some dogs of both groups, with high levels in the control group. In contrast, latent and active forms of MMP-9 were detected only in some animals with leishmaniasis. These results clearly demonstrate that MMP-9 is elevated in CSF of dogs with visceral leishmaniasis (VL). Although these results are preliminary, they suggest that MMP-9 might play a role in disruption of blood-brain barrier and/or blood-CSF barrier. While the presence of MMPs in CSF is not a condition exclusive to VL, their presence and persistence in CSF supports the hypothesis of an inflammatory state within CNS of dogs with VL.

ISOLADOS DE Cryptococcus neoformans, C. gattii e C. laurentii PRODUTORES DE PROTEASE E FOSFOLIPASE

Cryptococcosis is an opportunistic systemic mycosis, which may affect humans and various animal species, especially in cases of immunosuppression. The infection may be acquired through inhalation and by hematogenous route; the yeast has the ability to reach and colonize the central nervous system. The aim of this survey was the isolation of the Cryptococcus neoformans yeast from central nervous system of dogs in Rio de Janeiro city. Periodic collections were made from brain samples at the Rabies Diagnosis Laboratory in Instituto Municipal de Medicina Veterinaria Jorge Vaitsman in Mangueira, Rio de Janeiro. The isolation, the identification of this yeast and the evaluation of protease and phospholipase production were performed at the Laboratory of Environmental and Pathogenic Yeasts of the Universidade Federal Rural do Rio de Janeiro. A medium containing bovine serum albumin was used to evaluate protease production and to evaluate the production of phospholipase. The medium used consisted of egg yolk and CaCl2. According to the results obtained of the 166 clinical samples from dogs, we found four positive samples; one of these was positive for Cryptococcus laurentii, two were positive for Cryptococcus neoformans; and one for Cryptococcus gattii; all of them produced protease and phospholipase.

Distribution of the Inflammatory Lesions in the Central Nervous System of Dogs Affected with Disseminated and Ocular Form of Granulomatous Meningoencephalomyelitis

An aged Maltese dog (dog 1) showed gait ataxia for a month and suddenly died after convulsion. An aged Toy Poodle dog (dog 2) showed sudden blindness with unresponsive pupillary light reflexes and sudden death due to acute cardiac failure. Histological examination of the two dogs demonstrated severe granulomatous perivascular inflammation in the white matter throughout the central nervous system (CNS) including the brain and spinal cord. Based on the clinical and pathological findings, these dogs were diagnosed as granulomatous meningoencephalomyelitis (GME). In dog 2, the inflammatory changes predominated in the visual system such as the optic nerve, optic tract and optic radiation in the cerebrum (ocular form). Distribution pattern of the inflammatory lesions in the CNS was compared between the two dogs.

Non-suppurative Meningoencephalitis of Unknown Origin in Cats and Dogs: an Immunohistochemical Study

SummaryNon-suppurative meningoencephalitis of unknown cause is a frequent finding in dogs and cats. Fifty-three dogs and 33 cats with non-suppurative meningoencephalitis of unknown aetiology were examined immunohistochemically for 18 different infectious agents, including viruses, bacteria and prion proteinSc. In 14 (26%) of the dogs and 13 (39%) of the cats a causative agent was identified in the central nervous system (CNS), two dogs and one cat giving positive results for two infectious agents simultaneously. The study revealed infections with known causative agents (porcine herpes virus 1, feline infectious peritonitis virus, Escherichia coli) and a new disease pattern of parvovirus infection in the CNS of dogs and cats. Infection of the CNS with feline leukaemia virus was found in a cat. Five dogs and four cats gave positive results for West Nile virus (WNV) antigen. In one dog, canine parainfluenza virus antigen was detected in the brain. Four dogs and four cats gave positive results for encephalomyocarditis virus (EMCV). The significance of the detection of WNV and EMCV antigen requires further study. The aetiology remained undetermined in 39 dogs (74%) and 20 cats (61%). Although it is possible that non-infectious causes play a more important role than previously thought, infections with hitherto unrecognized agents cannot be ruled out.

Fungal Infections of the Central Nervous System in the Dog and Cat

Fungal infections of the central nervous system (CNS) in dogs and cats are uncommon. The purpose of this paper is to review the clinical signs, diagnostic tests, and therapeutic options of fungal infections of the CNS in the dog and cat. Clinical signs are dependent on lesion location and are often multifocal. Extraneural involvement is common. Antemortem diagnosis can be difficult and is definitively made via cytology, biopsy, or culture of an affected organ or cerebrospinal fluid (CSF). Magnetic resonance imaging can support a diagnosis and may assist in therapeutic decisions. Fungal serology can support a diagnosis when direct visualization of the organism is not possible. Long-term azole maintenance therapy is suggested to enhance survival and prevent relapse. Serial cerebrospinal fluid evaluation and magnetic resonance imaging may identify early relapse.

Granulomatous meningoencephalomyelitis in dogs: A review.

Granulomatous meningoencephalomyelitis (GME) is an inflammatory disease of the central nervous system in dogs that is characterised by focal or disseminated granulomatous lesions within the brain and/or spinal cord, non-suppurative meningitis and perivascular mononuclear cuffing. The aetiology of the disease remains unknown, although an immune-mediated cause is suspected. This article reviewed the typical history, clinical signs and pathology of the condition along with current opinions on pathogenesis. The potential differential diagnoses for the disease were discussed along with current treatment options.

Lesões histológicas no sistema nervoso central de cães com encefalite e diagnóstico molecular da infecção pelo vírus da cinomose canina

Dez amostras de urina de cães que apresentavam sinais clínicos sistêmicos e neurológicos indicativos da infecção pelo vírus da cinomose canina (CDV) foram analisadas pela técnica da reação em cadeia pela polimerase precedida de transcrição reversa (RT-PCR) para a detecção do RNA do CDV. O exame histopatológico foi realizado em fragmentos de cérebro, cerebelo e bexiga. Como controle negativo foram colhidos fragmentos de órgãos e urina de quatro cães sem sinais clínicos de doença infecciosa e que morreram por outras causas. Todos os cães (9/10) positivos em RT-PCR apresentaram alterações histológicas no cérebro e cerebelo, características de encefalite aguda (5/9) ou crônica (4/9) compatíveis com as causadas pelo CDV. Um dos cães com alterações clínicas neurológicas semelhantes às observadas em cinomose foi negativo na RT-PCR e apresentou alterações histopatológicas inespecíficas. Nas amostras de bexiga não foram observadas lesões histológicas. Todas as amostras biológicas provenientes dos cães-controle foram negativas na RT-PCR (urina) e não apresentaram alterações histológicas (fragmentos de órgãos). O trabalho evidenciou a especificidade da RT-PCR no diagnóstico precoce e ante mortem na infecção pelo CDV.

Inflammatory diseases of the central nervous system in dogs

Inflammatory diseases of the central nervous system (CNS) are important causes of seizures in dogs. Specific diseases include canine distemper, rabies, cryptococcosis, coccidioidomycosis, toxoplasmosis, neosporosis, Rocky Mountain spotted fever, ehrlichiosis, granulomatous meningoencephalomyelitis, and pug dog encephalitis. Inflammatory disorders should be considered when a dog with seizures has persistent neurological deficits, suffers an onset of seizures at less than 1 or greater than 5 years of age, or exhibits signs of systemic illness. A thorough history, examination, and analysis of cerebrospinal fluid are important in the diagnosis of inflammatory diseases. However, even with extensive diagnostic testing, a specific etiology is identified in less than two thirds of dogs with inflammatory diseases of the CNS.

Clinical and electroencephalographic findings of inflammatory and infectious diseases of the central nervous system in dogs: a retrospective study.

In the present study medical records of 97 dogs with inflammatory/infectious diseases of the central nervous system (CNS), including 26 dogs with a history of seizures, were retrospectively examined. The aims of the study were to analyse the incidence rate of seizures, to search for criteria to recognize specific inflammatory diseases and to determine how far electroencephalography may be useful in the early confirmation of encephalitis and encephalitis-associated seizures. The incidence rate of seizures in this dog population was 26.8%, and dogs with protozoal encephalitis had the highest rate. Signalment, history, extraneural and neurological signs including localization contributed only a little to a specific diagnosis. Surprisingly focal clinical signs were observed in two-thirds of the dogs. Either focal or multifocal clinical signs were related mainly to the forebrain in dogs with a history of seizures and to the brainstem in dogs without seizures. Cerebrospinal fluid (CSF) analyses were useful to separate encephalitis from other CNS diseases and to distinguish certain conditions from others in approximately half the cases. Electroencephalography (EEG) revealed two distinct patterns in 25 examined dogs with histopathologically confirmed disease entities, which were characterized by high voltage, slow activity (HVSA) with superimposed low voltage, fast activity (LVFA). These changes were consistent and no significant differences (P > 0.05) between dogs with and without seizures, nor between different disease entities, were noted. However, all the dogs with seizures had in addition a uniform paroxysmal EEG activity with a high voltage (mean = 106.3 microV), fast activity (mean = 8.5 Hz) pattern. Moreover in several dogs from the present study this pattern had a focal distribution despite the fact that clinically seizures appear generalized. Therefore it was concluded that EEG may be a very helpful diagnostic tool to confirm an early diagnosis of encephalitis and to separate potential seizure cases from those without seizures.

Up-regulation of major histocompatibility complex class II antigen expression in the central nervous system of dogs with spontaneous canine distemper virus encephalitis.

Major histocompatibility complex class II (MHC II) and canine distemper virus (CDV) antigen expression were compared by immunohistochemistry in the cerebellar white matter of ten dogs with naturally occurring canine distemper encephalitis. In addition, infiltrating mononuclear cells were characterized by employing poly- and monoclonal antibodies directed against human CD3, canine MHC II, CD5, B cell antigen and CDV-specific nucleoprotein. Positive antigen-antibody reaction was visualized by the avidin-biotin-peroxidase complex method on frozen sections. Histologically, neuropathological changes were categorized into acute, subacute, and chronic. In control brains, MHC II expression was weak and predominantly detected on resident microglia of the white matter and on endothelial, perivascular and intravascular cells. In CDV antigen-positive brains, MHC II was mainly found on microglia and to a lesser extent on endothelial, meningeal, choroid plexus epithelial, ependymal and intravascular cells. In addition, virtually all of the perivascular cells expressed MHC II antigen. CDV antigen was demonstrated most frequently in astrocytes. Of the perivascular lymphocytes, the majority were CD3-positive cells, followed by B cells. Only a small proportion of perivascular cells expressed the CD5 antigen. In addition, B cells and CD3 and CD5 antigen-positive cells were found occasionally in subacute and frequently in chronic demyelinating plaques. In acute encephalitis, CDV antigen exhibited a multifocal or diffuse distribution, and MHC II was moderately up-regulated throughout the white matter and accentuated in CDV antigen-positive plaques. In subacute encephalitis, moderate multifocal CDV antigen and moderate to strong diffuse MHC II-specific staining, especially prominent in CDV antigen-positive lesions, were observed. In chronic encephalitis, CDV antigen expression was restricted to single astrocytes at the edge of the lesions or was absent, while MHC II expression, especially prominent on microglia, was strongly up-regulated throughout the white matter, most pronounced in demyelinated plaques. In summary, in acute and subacute lesions without perivascular cuffs, MHC II expression correlated with the presence of CDV antigen. In contrast, in chronic lesions, MHC II expression on microglial cells was the most prominent despite a few CDV antigen-positive astrocytes, indicating that nonviral antigens may play an important role as triggering molecules for the process of demyelination.

Determination of Amphotericin B in cerebrospinal fluid by solid-phase extraction and liquid chromatography

A highly sensitive and reproducible liquid chromatography (LC) method for the determination of Amphotericin B in cerebrospinal fluid has been developed and validated. This LC-based method involves using nystatin as an internal standard and solid-phase extraction for sample preparation, followed by reversed-phase separation monitored by absorbance at 410 nm. The method has a limit of quantification of less than 1 ng ml −1 and excellent precision and accuracy, with both percentage relative standard deviation and percentage relative error less than 10%. The established linearity range was 1–10 ng ml −1 ( r 2 > 0.99). The extraction recovery of Amphotericin B from the cerebrospinal fluid is higher than 90% over the entire linear range. The method has been successfully employed for studying the penetration of Amphotericin B into the central nervous system in dogs and human.

Diagnosis of inflammatory and infectious diseases of the central nervous system in dogs: a retrospective study.

The medical records of 220 dogs with inflammatory/infectious diseases of the central nervous system (CNS) were retrospectively examined. The aims of the study were to determine if clinical and clinicopathologic data (not including biopsy or necropsy examination) could distinguish inflammatory CNS diseases from diseases of other types, and to search for criteria allowing differentiation of specific inflammatory diseases. The signalment, historical findings, extraneural and neurological signs, and the lesion site contributed marginally to a specific diagnosis. Multifocal signs were only noticed in one third of the dogs with inflammatory/infectious diseases. Particular neurological abnormalities were more frequent in certain diseases than in others (eg, myoclonus was frequent in dogs with distemper, but it was also found in those with other meningoencephalomyelitides). Hematologic findings contributed to the diagnosis in certain conditions (eg, canine distemper encephalitis, protozoal encephalomyelitis, steroid-responsive meningitis-arteritis). Cerebrospinal fluid examinations, including immunoglobulin G index and cytology were useful to separate meningoencephalomyelitides from the other CNS diseases and to distinguish certain conditions from others. In most cases a specific diagnosis depended on a combination of clinical signs and ancillary diagnostic aids. Still, a specific diagnosis remained very difficult, if not impossible, in at least one third of the dogs.

Saturable transport of insulin from plasma into the central nervous system of dogs in vivo. A mechanism for regulated insulin delivery to the brain.

By acting in the central nervous system, circulating insulin may regulate food intake and body weight. We have previously shown that the kinetics of insulin uptake from plasma into cerebrospinal fluid (CSF) can best be explained by passage through an intermediate compartment. To determine if transport kinetics into this compartment were consistent with an insulin receptor-mediated transport process, we subjected overnight fasted, anesthetized dogs to euglycemic intravenous insulin infusions for 90 min over a wide range of plasma insulin levels (69-5,064 microU/ml) (n = 10). Plasma and CSF samples were collected over 8 h for determination of immunoreactive insulin levels, and the kinetics of insulin uptake from plasma into CSF were analyzed using a compartmental model with three components (plasma-->intermediate compartment-->CSF). By sampling frequently during rapid changes of plasma and CSF insulin levels, we were able to precisely estimate three parameters (average standard deviation 14%) characterizing the uptake of insulin from plasma, through the intermediate compartment and into CSF (k1k2); insulin entry into CSF and insulin clearance from the intermediate compartment (k2 + k3); and insulin clearance from CSF (k4). At physiologic plasma insulin levels (80 +/- 7.4 microU/ml), k1k2 was determined to be 10.7 x 10(-6) +/- 1.3 x 10(-6) min-2. With increasing plasma levels, however, k1k2 decreased progressively, being reduced sevenfold at supraphysiologic levels (5,064 microU/ml). The apparent KM of this saturation curve was 742 microU/ml (approximately 5 nM). In contrast, the rate constants for insulin removal from the intermediate compartment and from CSF did not vary with plasma insulin (k2 + k3 = 0.011 +/- 0.0019 min-1 and k4 = 0.046 +/- 0.021 min-1). We conclude that delivery of plasma insulin into the central nervous system is saturable, and is likely facilitated by an insulin-receptor mediated transport process.

An immunohistochemical and ultrastructural study on age-related astrocytic gliosis in the central nervous system of dogs.

The pattern of astrocytic gliosis (AG) was examined in 2-month-old to 18-year-old dogs using glial fibrillary acidic protein (GFAP) immunohistochemistry and electron microscopy. Coronal sections from various levels of the central nervous system (CNS) were stained with hematoxylin & eosin, Luxol Fast Blue, Nissl, and Bodian in addition to GFAP. A consistent pattern of age-related AG was observed in the dogs. The white matter, cortico-medullary junction, and subcortical nuclei in the cerebrum, central nuclei in the cerebellum, various nuclei in the brain stem, and grey matter of the spinal cord showed even and intense GFAP staining. AG was also prominent in the cerebral and cerebellar cortices and thalamus. Moderate AG was observed in the hippocampus and white matter of the cerebellum and spinal cord. Electron microscopy demonstrated increased number of profiles of degenerative neural components in the vicinity of hypertrophic astrocytes in the cerebral cortex of the aged dogs. Moderate to severe AG was consistently shown in the CNS of the aged dogs. In contrast, young normal dogs showed minimum amounts of GFAP-positive astrocytes in the CNS. These findings suggest that the observed AG in the CNS of the dogs is a morphological expression of aging.

Lectin Histochemical Evalution of Neuronal Glycosaminoglycan Content Following Bone Marrow Transplantation in Dogs with MPS I

The storage of glycosaminoglycans (GAGs) within cells of the central nervous system of dogs with mucopolysaccharidosis I (MPS I) was studied. Lectins that detect these stored GAGs were applied to formalin fixed tissues from 5 MPS I-affected dogs, 2 of which were previously treated by littermate bone marrow transplantation (BMT), and from 2 unaffected littermate controls.In all transplant recipients there was reduced reactivity of the central nervous system (CNS) neurons with soybean agglutinin and horse gram agglutinin indicating that BMT results in reduced levels of those GAGs stored excessively in MPS I. Wheat germ agglutinin was found to react less strongly with cells from treated or untreated dogs despite its predicted binding to sugars in GAGs that are known to accumulate in MPS I. These findings, coupled with previously reported total brain GAG content, show that neuronal storage of GAG is reduced following BMT in canine MPS I. (The J Histotechnol 14:183, 1991)