Evaluation of immunologic parameters in canine glioma patients treated with an oncolytic herpes virus

AIM

To molecularly characterize the tumor microenvironment and evaluate immunologic parameters in canine glioma patients before and after treatment with oncolytic human IL-12-expressing herpes simplex virus (M032) and in treatment naïve canine gliomas.

METHODS

We assessed pet dogs with sporadically occurring gliomas enrolled in Stage 1 of a veterinary clinical trial that was designed to establish the safety of intratumoral oncoviral therapy with M032, a genetically modified oncolytic herpes simplex virus. Specimens from dogs in the trial and dogs not enrolled in the trial were evaluated with immunohistochemistry, NanoString, Luminex cytokine profiling, and multi-parameter flow cytometry.

RESULTS

Treatment-naive canine glioma microenvironment had enrichment of Iba1 positive macrophages and minimal numbers of T and B cells, consistent with previous studies identifying these tumors as immunologically "cold". NanoString mRNA profiling revealed enrichment for tumor intrinsic pathways consistent with suppression of tumor-specific immunity and support of tumor progression. Oncolytic viral treatment induced an intratumoral mRNA transcription signature of tumor-specific immune responses in 83% (5/6) of canine glioma patients. Changes included mRNA signatures corresponding with interferon signaling, lymphoid and myeloid cell activation, recruitment, and T and B cell immunity. Multiplexed protein analysis identified a subset of oligodendroglioma subjects with increased concentrations of IL-2, IL-7, IL-6, IL-10, IL-15, TNFα, GM-CSF between 14 and 28 days after treatment, with evidence of CD4⁺ T cell activation and modulation of IL-4 and IFNγ production in CD4⁺ and CD8⁺ T cells isolated from peripheral blood.

CONCLUSION

These findings indicate that M032 modulates the tumor-immune microenvironment in the canine glioma model.

Magnetic resonance imaging features of brain stem abscessation in two cats

Premortem magnetic resonance imaging (MRI) was performed in two cats with brain stem abscessation confirmed post mortem by histology and recovery of multiple bacterial species. The MRI features of the abscesses were distinctive and included a thick and marked enhancement of the abscess capsule and extension of the lesion from a tympanic bulla in one cat. A focal area of increased signal intensity was present on T2-weighted images. A circumscribed area of decreased signal intensity was surrounded by a ring of increased signal intensity on precontrast T1-weighted images. A center of decreased signal intensity with a thick, markedly enhanced abscess capsule was observed on post contrast T1-weighted images. These findings are compared to the current experimental and clinical literature of brain abscess. The underlying pathogenesis of MRI features is reviewed.

Clinical features of trigeminal nerve-sheath tumor in 10 dogs

Nerve-sheath tumor was diagnosed in 10 dogs with clinical signs of unilateral trigeminal nerve dysfunction. Unilateral temporalis and masseter muscle atrophy were present in all cases. An enlarged foramen and distorted rostral petrous temporal bone were seen with computed tomography imaging in one case. Magnetic resonance imaging was used to identify the lesion accurately in seven cases. Surgery was performed for biopsy and lesion removal in three cases. Cases not treated had a progressive course eventually resulting in euthanasia or death. Of the cases treated surgically, one case is alive without disease progression 27 months after surgery. Survival times of the nontreated cases ranged from five to 21 months.

Surgical management of atlantoaxial subluxation in 23 dogs

Twenty-eight surgical procedures were performed in 23 dogs with atlantoaxial subluxation. Dorsal stabilization in seven dogs resulted in two recoveries and five failures of fixation. Ventral decompression and stabilization in 18 dogs resulted in eight recoveries and four failures of fixation. Six dogs died or were euthanatized within 7 days of ventral stabilization. Using either technique, four of seven nonambulatory dogs recovered.

Vertical transmission of Neospora caninum in dogs

Herein we report the development of a canine model to examine transplacental and/or transmammary transmission of Neospora caninum. Six pregnant bitches were experimentally infected with N. caninum on day 21 of gestation. One bitch successfully delivered a litter of 3 live pups. These pups showed slight proprioception deficits, increased muscle tone, and spasticity in both pelvic limbs; however, N. caninum was neither demonstrated by bioassay in cell culture nor seen in histological sections of tissues from these pups. The remaining 5 bitches aborted. Neospora caninum was isolated from tissues of 4 of the experimentally infected bitches and pups from 2 of the miscarried litters. Experimental infections of 2 litters of 5-day-old nursing pups produced variable results. Neospora caninum was isolated from 2 of 2 inoculated pups in 1 litter and 3 of 6 inoculated pups in the second litter.

Clinicopathologic effects of a 21-aminosteroid compound (U74389G) and high-dose methylprednisolone on spinal cord function after simulated spinal cord trauma

A model simulating acute-compressive spinal cord trauma at the second lumbar spinal cord segment (100 g, 300 seconds) was used to evaluate the efficacy of a vehicle control, methylprednisolone sodium succinate (MPSS), and a 21-aminosteroid compound (U74389G). Dogs were allocated into one of five treatment groups (A to E) using ultrasonographic determination of spinal cord diameters to ensure even distribution of spinal cord diameters among the treatment groups. Initial dosages of the vehicle control (A), methylprednisolone (30 mg/kg of body weight) (B), or U74389G (30 mg/kg, 3 mg/kg, or 10 mg/kg of body weight) (C, D, or E, respectively) were administered intravenously 30 minutes after trauma. Dosages were reduced by one-half for 2 and 6 hour treatments. Then every 4 hours for 42 hours, dosages were reduced one-third and one-sixth from the original dose of methylprednisolone and U74389G, respectively. Neurological examinations were performed daily for 21 days. Histopathological examination of the traumatized spinal cord showed malacic and degenerative lesions. Although significant differences in some portions of the neurological and histopathologic examinations were observed, clinical efficacy for MPSS and U74389G could not be established in this model.

Composition of cerebrospinal fluid in healthy adult llamas

Cerebrospinal fluid and serum were obtained from 17 adult, healthy llamas (9 males, 1 castrated male, and 7 females). Osmolality; activities of lactate dehydrogenase and creatine kinase; and concentrations of glucose, sodium, chloride, potassium, total protein, and albumin were determined in serum and CSF. Total and differential cell counts were determined in CSF, and electrophoresis of CSF proteins was performed. Total nucleated cell count was low, 0 to 3/microliters, which is lower than that reported for other domestic species and is similar to values in healthy people. Differential leukocyte percentages were disparate depending on the degree of blood contamination. Blood contamination influenced the percentage of neutrophils and eosinophils in CSF. Samples with few erythrocytes had differential leukocyte distribution similar to that of other species: mostly lymphocytes, fewer monocytoid cells, and scant neutrophils. Older llamas had a few eosinophils in the CSF. Total protein, albumin, and gamma-globulin concentrations in llamas were similar to values in cattle and were higher than values in most domestic species. Glucose concentration in CSF was approximately 40% of the value in serum (nonruminant animals and peoply typically have CSF glucose concentration that is approximately 60 to 80% of the serum glucose concentration). Sodium and Cl concentrations in CSF were higher than those in serum, whereas K concentration was lower in CSF, compared with serum. Activities of creatine kinase and lactate dehydrogenase in CSF were markedly lower than those in serum, and the ranges of values in this group of healthy llamas were narrow.

Ultrasound-guided brain biopsy in dogs

Ultrasound-guided brain biopsy of the cingulate gyrus and the head of the caudate nucleus was performed in clinically normal dogs. Dogs survived the surgery, and neurologic deficits were not detected in the 14-day postoperative period. Magnetic resonance imaging detected changes in the brain associated with biopsy in 9 dogs (90%) immediately after surgery and in 6 dogs (60%) 14 days after surgery. Fourteen days after surgery, sonography of the brain, performed through the skin overlying the burr hole, detected changes associated with biopsy in 9 dogs (90%). Histopathologic changes evident in the brain 14 days after surgery consisted of focal malacia and hemorrhage with associated subacute encephalomeningitis. Postmortem examination indicated that the biopsy specimen was accurately obtained from the desired site in 9 dogs (90%). Tissue specimens suitable for histologic examination were obtained from 10 dogs (100%). Accuracy and low morbidity of ultrasound-guided biopsy indicate that this may be a useful technique for diagnosis of focal brain disease in dogs.

Cerebrospinal fluid composition of cattle with endotoxin-induced mastitis treated with isotonic (0.9%) or hypertonic (7.5%) sodium chloride

This study examined the safety of intravenous hypertonic saline in cattle with experimental gram-negative endotoxemia. Cerebrospinal fluid (CSF) composition was examined in five control cows and eight treated cows 24 hours after the intramammary infusion of 1 mg of endotoxin. Four of the endotoxin challenged cows were treated intravenously with isotonic (0.9%) sodium chloride and four cows were treated intravenously with hypertonic (7.5%) sodium chloride. Decreased CSF osmolality, and sodium and alpha globulin concentrations and increased CSF concentrations of beta globulin were observed in both endotoxin-challenged saline-treated groups. No CSF compositional differences were observed between endotoxin-challenged cows receiving isotonic or hypertonic saline. Although no cytologic or biochemical evidence of salt poisoning was observed in cows receiving hypertonic saline, significant changes were observed in the CSF composition of both endotoxin-infused saline-treated groups.

Composition and analysis of cerebrospinal fluid in clinically normal adult cattle

Cerebrospinal fluid and serum were obtained from 16 clinically normal adult cows (11 dairy, 5 beef). Sodium, potassium, magnesium, total protein, and albumin concentrations, osmolality, and lactate dehydrogenase and creatine kinase activities, were quantified in CSF and serum. Total and differential cell counting, protein electrophoresis, and IgG quantification were performed on CSF. Statistical analyses of these variables, including mean, SEM, range, and 95% confidence intervals, were performed. Effects of blood contamination were evaluated, and were found to be negligible for all measured constituents. Correction factors for CSF creatine kinase and lactate dehydrogenase activities accounting for cellular contamination were developed. Total nucleated cell count was similar to counts in CSF of other species, but higher than values in healthy people. Differential leukocyte count in CSF was similar to that reported in CSF of other domestic animals: mostly lymphocytes, fewer monocytoid cells, and scant neutrophils. Cerebrospinal fluid protein concentration was higher than concentration reported for dogs, goats, and people, but was similar to values reported for horses. Beef cows had higher CSF total protein concentration than did dairy cows; also, beef cows had higher CSF gamma-globulin concentration. The concentration of sodium in CSF was slightly higher than the value in serum, and potassium concentration was lower than the value in serum. In contrast to studies of human beings, CSF osmolality was generally less than serum osmolality in the cows studied. Reference values for CSF electrolyte concentrations and osmolality are useful for diagnosis of salt poisoning and for assessment of the effects of fluid therapy. Magnesium concentration was lower in CSF, compared with serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Myelitis and meningitis

Animals with meningomyelitis have clinical neurologic signs that typically range from paraspinal discomfort to tetraplegia; however, most affected animals also show evidence of multifocal CNS involvement with brain stem and cerebral cortical structures being affected most commonly. The cause, duration, and host response to the disease process will determine the clinical signs in individual animals. Confirmation of a specific causative agent is difficult, but CSF analysis and immunotesting of serum and CSF yield the most rewarding diagnostic results. Successful treatment is based on formulation of an appropriate and aggressive therapeutic regimen. In some diseases, no effective treatment is available, and some animals may develop permanent neurologic disabilities.

Hip dysplasia with bilateral ischiatic nerve entrapment in a dog

Dysfunction of both ischiatic nerves was detected in a 5-year-old spayed Labrador Retriever with radiographic evidence of severe bilateral hip dysplasia. Marked hyperflexion of the hip and stifle was evident when the dog walked. Results of electromyography confirmed the ischiatic nerve involvement. At staged operations, both ischiatic nerves were found to be compressed between the sacrotuberous ligament and proliferative tissue around the hip. One year after surgery, electromyographic and physical findings were essentially normal.

Electrophoretic determination of albumin and gamma globulin concentrations in the cerebrospinal fluid of dogs with encephalomyelitis attributable to canine distemper virus infection: 13 cases (1980-1987)

Thirteen dogs with encephalomyelitis attributable to canine distemper virus infection were classified into 3 groups on the basis of histopathologic evidence of virus-induced lesions in CNS tissue. Analysis of data indicated a similarity within groups when arranged by age, clinical neurologic signs, and alterations in the CSF electrophoretic protein values. Comparison with results in dogs with experimentally induced canine distemper encephalomyelitis suggested that when grouped by age, CSF electrophoretic values are helpful in predicting the CNS histopathologic changes in dogs with naturally acquired canine distemper encephalomyelitis.

Neurologic and otologic disorders of geriatric patients

The geriatric animal is at increased risk to develop a variety of neurologic conditions. The diagnosis of these conditions can be a challenge to veterinary practitioners. Many of these conditions have a breed predilection and specific neurologic findings that can greatly aid in obtaining a diagnosis. Others demand many in-depth tests that require extra care in their selection and performance. Obtaining the correct diagnosis is rewarding in those cases where therapy can be beneficial. However, as in most chronic conditions, the correct diagnosis results in a prognosis that is often poor at best and frustrating to both the owner and veterinarian.

Myeloencephalopathy with eosinophilic refractile bodies (Rosenthal fibers) in a Scottish terrier

Myeloencephalopathy with diffuse Rosenthal fiber formation (Alexander's disease) was detected in a 9-month-old Scottish Terrier with progressive tetraparesis. Additional abnormalities included an electroencephalogram characteristic of an encephalopathy and a narrowed intervertebral disk space at C2-3. The diagnosis of Alexander's disease is uncommon in human and veterinary medicine. Results from this case and previous reports suggest that this disease in the dog may have a congenital or genetic basis.

Total protein, albumin quota, and electrophoretic patterns in cerebrospinal fluid of dogs with central nervous system disorders

Cerebrospinal fluid was analyzed for total protein, albumin quota, and electrophoretic patterns of albumin and alpha-, beta-, and gamma-globulins in 10 healthy dogs and 35 dogs with CNS disorders. Values obtained in healthy dogs were used to establish control data. Samples also were collected from dogs with neurologic diseases that were classified according to clinical and pathologic diagnosis as inflammation, neoplasm, and spinal cord compression. The albumin quota and total CSF albumin values were used as indicators of blood-brain barrier disturbance. Four patterns were observed on agarose electrophoresis that included intrathecal immunoglobulin production, intrathecal immunoglobulin production combined with blood-brain barrier disturbance, blood-brain barrier disturbance, and unaltered CSF. These patterns correlated with the observed clinical and pathologic conditions. Seemingly, agarose electrophoresis of CSF is a simple and reliable technique that aids in the diagnosis of CNS disorders of dogs.

Myeloencephalopathy resembling Alexander's disease in a Scottish terrier dog

Diffuse degenerative myeloencephalopathy resembling Alexander's disease in a tetraparetic 9-month-old Scottish terrier dog is described. There were widespread deposits of Rosenthal fibers throughout brain and spinal cord in subpial, subependymal, perivascular and white matter regions. A diffuse proliferation of pleomorphic astrocytes in the white matter and subependymal areas was also seen. Demyelination was not a salient feature of the disease.

Effects of dexamethasone and surgical hypotension on hepatic morphologic features and enzymes of dogs

Effects of corticosteroids and surgical stress on hepatic morphologic features and enzymes were studied in 18 mature dogs of mixed breeding: group 1, control (n = 3); group 2, dexamethasone (n = 5); group 3, dexamethasone and surgery (n = 5); and group 4, surgery (n = 5). Dexamethasone (2.2 mg/kg of body weight twice a day subcutaneously) was administered for 8 days in groups 2 and 3 dogs. All dogs were anesthetized with thiopental for 10 minutes on days 0, 2, and 4. On day 2, dogs in groups 3 and 4 were intubated and maintained on methoxyflurane and oxygen, and a liver biopsy, hemilaminectomy (T13-L1), and 15 minutes of hypotension (75/45 mm of Hg) induced by methoxyflurane were done. Serum alkaline phosphatase (ALP) activity, ALP isoenzymes, and alanine aminotransferase (ALT) activity were determined on days 0, 2, 3, 5, and 8. All dogs were euthanatized and necropsied on day 8. Serum hepatic enzyme activity and hepatic morphologic characteristics were normal for group 1 control dogs. The mean ALP and ALT were significantly (P less than 0.05) increased in dogs in groups 2, 3, and 4. In group 2, the mean ALP (days 5 to 8) and ALT (day 8) were significantly (P less than 0.05) increased. In group 3, the mean ALP and ALT activities were significantly increased on days 2 to 8. In group 4, the mean ALP was significantly increased on days 2 to 8 and the mean ALT was significantly increased on days 3 and 5. All other values were normal. A single isoenzyme band (Rf = 0.399 +/- 0.023, mean +/- SD) was identified in all dogs. Hepatic morphologic changes attributed to dexamethasone were mild-to-moderate vacuolation in a diffuse distribution on day 2 (group 3) and aggregates of moderate-to-severe vacuolation in mainly a periportal distribution on day 8 (groups 2 and 3).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of dexamethasone and surgical hypotension on the stomach of dogs: clinical, endoscopic, and pathologic evaluations

Effects of dexamethasone and surgical hypotension on the gastric mucosa of 15 dogs was evaluated by clinical, endoscopic, and pathologic studies. Dexamethasone produced acute reddening of the gastric mucosa with frank hemorrhage, digested blood, and possible gastric erosions, whereas dogs treated by surgical hypotension did not have marked changes in the gastric mucosa. Gastrointestinal disease observed in dogs with spontaneous spinal cord injury that were given dexamethasone and decompressive spinal surgery was not produced. The role of corticosteroids and surgical hypotension in the pathogenesis of gastric lesions and the potential for spinal cord injury to produce gastrointestinal disease is discussed.

Idiopathic facial paralysis in the dog

Facial nerve paralysis of acute onset is reported in seven mature dogs, five of which were cocker spaniels. The clinical signs were characterised by ear drooping, lip commissural paralysis, sialosis, and collection of food on the paralysed side of the mouth. All dogs showed absent menace responses and trigeminofacial/acousticofacial reflexes. Horner's syndrome was not present in any dog. In four dogs, bilateral facial paralysis developed. The facial paralysis was unrelated to otitis media. Electrodiagnostic studies revealed denervation potentials and absent evoked muscle potentials. Facial nerve biopsies from two cases showed nerve fibre degeneration and apparent loss of larger diameter myelinated fibres. The condition has been termed idiopathic facial paralysis since the aetiopathogenesis is presently unknown.