Angiographic evaluation of the rat carotid balloon injury model.

RATIONALE: The rat carotid balloon-injury (BI) model is a widely used model of intimal hyperplasia (IH) and vascular remodeling. A variable degree of IH after BI has been previously reported, and we have encountered technical challenges and suboptimal results with the original method. OBJECTIVE: To evaluate the original rat carotid artery BI method with the use of micro-angiography. We tested the hypothesis that in order to obtain an optimal arterial response, BI should be limited to the common carotid artery with preservation of blood flow. METHODS AND RESULTS: The left common carotid artery (CCA) was injured by one of three different methods. Carotid angiograms and pathology were examined 14 days after BI. A 2F Fogarty balloon catheter inflated to 2 atm inside the aortic arch would not slide back into the common carotid artery until deflation to 0.5 to 0.7 atm. Four out of five (80%) vessels injured with this method developed excessive inflammation without discernible IH. Six out of nine (66%) arteries that underwent BI limited to the CCA at 2 atm developed the largest angiographic stenosis (p=0.003) and IH (0.20±0.03 mm(2), p=0.028). Ten out of eleven (91%) arteries injured with a variable pressure of 1.5 to 2.2 atm, based on the operator's feedback, developed considerable IH (0.12±0.02 mm(2)). All injured carotid arteries with preserved blood flow on angiography developed IH with intact histological boundaries. CONCLUSIONS: Optimal IH with preservation of histological boundaries is achieved by graded BI limited to the CCA that preserves carotid blood flow.

Compound heterozygous mutation with a novel splice donor region DNA sequence variant in the succinate dehydrogenase subunit B gene in malignant paraganglioma.

Pheochromocytoma and paraganglioma (PGL) are rare neuroendocrine tumors in children. Apparently sporadic cases of PGL may harbor germline mutations in the succinate dehydrogenase (SDHx) gene. SDHB mutations are associated with malignant disease. We report a 13-year-old African American boy with diffusely metastatic PGL and compound heterozygous mutation leading to a novel splice donor region DNA sequence variant in the SDHB gene. Family history was positive for non-classical congenital adrenal hyperplasia and pituitary adenoma. After surgical resection of the primary PGL and chemotherapy, he was treated with metaiodobenzy lguanidine (MIBG) combined with arsenic trioxide. At 3-year follow-up, he had stable disease.

Age-related differences in rabbits during experimental Staphylococcus aureus keratitis.

PURPOSE: To analyze age-related changes in susceptibility to experimental Staphylococcus aureus keratitis and purified alpha-toxin in rabbits. METHODS: Intrastromal injection of S. aureus (100 colony-forming units [CFUs]) induced keratitis in young (6-8 weeks) and aged (approximately 30 months) New Zealand White rabbits. Bacteria and polymorphonuclear leukocytes (PMNs) per cornea were quantified. Purified alpha-toxin at 1, 10, 25, or 50 hemolytic units (HU) or heat-inactivated alpha-toxin was intrastromally injected into corneas, and pathologic changes were determined by slit lamp examination (SLE) and histopathologic analysis. alpha-Toxin hemolysis assays were performed using erythrocytes from young and aged rabbits. RESULTS: S. aureus keratitis produced significantly higher SLE scores in young rabbits than in aged rabbits at 15, 20, and 25 hours postinfection (PI; P < or = 0.001); aged rabbits essentially recovered from S. aureus keratitis by 7 days PI. At 25 hours PI, numbers of CFUs and PMNs in corneas of young and aged rabbits were equivalent (P > or = 0.6); the bacterial burden in aged rabbits declined by 5 logs per cornea from day 1 to day 7 PI. Intrastromal injection of > or =10 HU alpha-toxin also produced significantly more disease in young than in aged rabbit corneas (P < or = 0.05), whereas 1 HU or heat-inactivated toxin yielded negligible pathologic changes in either group. Hemolysis assays of erythrocytes from young rabbits demonstrated greater susceptibility to alpha-toxin compared with those from aged rabbits. CONCLUSIONS: Corneas and erythrocytes of young rabbits, relative to aged rabbits, are significantly more susceptible to S. aureus keratitis and to alpha-toxin.

Neuropathologic lesions and CSF morphine concentrations during chronic continuous intraspinal morphine infusion. A clinical and post-mortem study.

Seven patients with chronic intractable pain due to cancer were given chronic intraspinal narcotic administration (CINA) and subsequently underwent post-mortem examination. All deaths were unrelated to CINA. Two of these patients were found to have clinically unsuspected posterior column degeneration. Both patients had had epidural catheters placed, and one had received prior radiotherapy to ports which included parts of the spinal cord. In retrospect, it is impossible to ascertain whether the degeneration occurred before or after infusion of morphine began. Review of the potential causes for posterior column degeneration suggests that neuropathy associated with malignant disease is more likely the cause of the degeneration rather than intraspinal infusion of morphine. However, continued vigilance at autopsy is recommended. In addition, utilizing a new method for measuring cerebrospinal fluid (CSF) concentrations of morphine via high-pressure liquid chromatography, CSF morphine levels at steady state were measured in 5 patients. These levels were much lower than peak levels previously reported following bolus intraspinal administration. The ability of these measurements to contribute to knowledge of efficacy, toxicity, lumbar-cisternal concentration gradients, and differentiation of tolerance from drug delivery problems is discussed.

Inhibiting caspase-8 after injury reduces hypoxic-ischemic brain injury in the newborn rat.

A broad spectrum caspase inhibitor reduces brain injury. Will a caspase-8 inhibitor provide protection? Seven-day-old rat pups had the right carotid artery ligated, then were subjected to 2.5 h of 8% oxygen. Caspase-8 activity in the right cortex was measured enzymatically. Caspase-8 activity was increased at 12 and 24 h after injury and IETD-CHO, (Ac-Ala-Ala-Val-Ala-Leu-Leu-Pro-Ala-Val-Leu-Leu-Ala-Pro-Ile-Glu-Thr-Asp-CHO, CHO is aldehyde) a cell permeable caspase-8 inhibitor, given by i.c.v. injection after the hypoxic period eliminated this increase with significant effect at 15 and 50 microg/pup (1.7 micromol/kg). Thirty pups were randomly assigned to receive 50 microg/pup of IETD-CHO or vehicle i.c.v. immediately after the hypoxic period. The loss of brain weight in the right hemisphere 22 days after injury was 29+/-5% in the vehicle-treated animals and 12+/-5% in the IETD-CHO-treated animals (P<0.05). Inhibiting caspase-8 activity after hypoxic-ischemic brain injury reduces brain injury.

Inhibiting caspase-9 after injury reduces hypoxic ischemic neuronal injury in the cortex in the newborn rat.

A broad spectrum caspase inhibitor reduces hypoxic ischemic brain injury. We hypothesized that a specific caspase-9 inhibitor would provide similar protection. Seven-day-old rat pups had the right carotid artery ligated, then were subjected to 2.5 h of 8% oxygen. Caspase-9 activity in the right cortex was measured enzymatically. Caspase-9 activity was increased at 6, 12, and 24 h after injury. LEHD-CHO is a specific cell permeable caspase-9 inhibitor. LEHD-CHO given intracerebroventricularly (i.c.v.) into the brain after the hypoxic period eliminated the increase in caspase-9 activity. The greatest effect was at a dose of 50 microg/pup (1.6 micromol/kg). Fifty-two pups were randomly assigned to receive 50 microg/pup of i.c.v. LEHD-CHO or vehicle immediately after the hypoxic period. The loss of cortical neurons in the right hemisphere 22 days after injury was 52.0+/-8% in the vehicle treated animals, and 25+/-9% in the LEHD-CHO treated animals (P<0.05). Inhibiting caspase-9 activity reduces loss of neurons after brain injury.

Aortic response to balloon injury in obese Zucker rats.

The small diameter of the carotid artery is not compatible with the evaluation of clinically available endovascular devices in the carotid balloon-injury (BI) model. We developed an endovascular BI model in the rat descending aorta, whose size is compatible with available endovascular instruments. We also tested the hypothesis that neointima formation is enhanced in the aorta of obese Zucker rats (OZR) compared with lean Zucker rats (LZR). Left external carotid arteriotomies and BI of the thoracic and abdominal aorta were performed by using a balloon catheter. Aortograms and aortic pathology were examined at 2, 4, and 10 wk after BI. At 10 wk after BI, the abdominal aorta in OZR had narrowed 8.3% ± 1.1% relative to baseline compared with an expansion of 2.4% ± 2.2% in LZR. Simultaneously, the thoracic aorta had expanded 9.5% ± 4.3% in LZR compared with stenosis of 2.8% ± 1.6% in OZR. Calculation of the intimal:medial thickness ratio revealed significantly increased neointimal formation in the OZR descending aorta compared with that in LNR. In conclusion, this minimally invasive BI model involving the rat descending aorta is compatible with available endovascular instruments. The descending aorta of OZR demonstrates enhanced neointimal formation and constrictive vascular remodeling after BI.

Asymptomatic aneurysm of the cavernous and supraclinoid internal carotid artery in a patient with Balamuthia mandrillaris encephalitis.

This is the first report to our knowledge of the successful treatment of an asymptomatic mycotic aneurysm associated with Balamuthia mandrillaris encephalitis. A 27-year-old male with end-stage renal disease presented with generalized seizures following renal transplantation. MRI demonstrated multiple brain masses and an aneurysm of the cavernous and supraclinoid carotid artery. Autopsy of the donor's brain revealed Balamuthia encephalitis. The patient was placed on an anti-amebic regimen, his condition improved, and 126 days after the kidney transplant, MRI brain showed resolution of the aneurysm and improvement of the enhancing lesions. Balamuthia mandrillaris has been shown to cause a granulomatous encephalitis, with prominent vasculitis. This is the first report to demonstrate the risk of aneurysm formation associated with this infection. Prolonged anti-amebic treatment resulted in resolution of the aneurysm without clinical evidence of subarachnoid hemorrhage.

Intraosseous meningioma of the sphenoid bone.

A 50-year-old female presented to the Neurosurgery clinic with dimness of vision and proptosis of her right eye. Maxillofacial CT showed a hyperostotic mass involving the right sphenoid ridge, anterior clinoid process, orbital roof, and lateral wall with mass effect on the intraorbital contents and lateral wall of the sphenoid sinus. MRI of the brain and orbit showed a heterogeneous enhancement of underlying dura and right orbital apex extending into the cavernous sinus. The patient underwent a staged resection in which pathological analysis showed an intraosseous meningioma. When a hyperostotic mass of the skull is encountered, meningioma should be considered in the differential diagnosis. Although primary intraosseous meningiomas are rare benign tumors, they can be associated with morbidity secondary to mass effect.

Properties of PASP: a Pseudomonas protease capable of mediating corneal erosions.

PURPOSE: To analyze PASP in terms of its gene distribution and expression, its corneal pathologic effects, its enzymatic properties, and the protectiveness of the immune response to this protease. METHODS: Twenty-five strains of P. aeruginosa were analyzed for the PASP gene and secreted protein by PCR and Western blot analysis, respectively. Active recombinant (r)PASP (10 microg/20 microL) or heat-inactivated rPASP was intrastromally injected into rabbit corneas. Pathologic changes were monitored by slit lamp examination (SLE) and histopathology. Purified rPASP was assayed for cleavage of collagens and susceptibility to TLCK. Rabbit antibody to rPASP was produced and tested for enzyme inactivation, and actively immunized rabbits were challenged by intrastromal injection of active rPASP (5 microg). RESULTS: All 25 strains of P. aeruginosa analyzed were positive for the PASP gene and protein. SLE scores of eyes injected with active rPASP were significantly higher than control eyes at all postinjection times (PI; P or= 10,000) was produced, but this antibody did not protect against active rPASP challenge. CONCLUSIONS: PASP is a commonly produced Pseudomonas protease that can cleave collagens and cause corneal erosions.

Neuroprotective effects of sodium orthovanadate after hypoxic-ischemic brain injury in neonatal rats.

Sodium orthovanadate (SOV), a competitive inhibitor of protein tyrosine phosphatases, is neuroprotective in adult animals following an ischemic event. The present study evaluated whether SOV might be protective in a rat pup hypoxic-ischemic (HI) model. Seven-day-old rat pups had the right carotid artery permanently ligated followed by 140 min of hypoxia (8% oxygen). SOV 1.15, 2.3, 4.6, 9.2 or 18.4 mg/kg and vehicle were administered by i.p. injection at 5 min after reoxygenation. Brain damage was evaluated by weight loss of the right hemisphere at 22 days after hypoxia and by gross and microscopic morphology. SOV lowered blood glucose at doses of 1.15, 2.3 and 4.6 mg/kg and induced toxic effects at 9.2mg/kg. The doses of 2.3 and 4.6 mg/kg of SOV significantly reduced brain weight loss (p<0.05), but treatment with 1.15 or 9.2mg/kg did not. SOV 4.6 mg/kg also improved the histopathologic score and diminished the HI induced reduction of Akt and ERK-1/2 phosphorylation in the cortex (p<0.05) and increased the density of BrdU-positive cells in the subventricular zone (p<0.01). In conclusion, SOV has neuroprotective effects in the neonatal rat HI model partially mediated by activating Akt and ERK-1/2 pathways.

Glial S100B Positive Vacuoles In Purkinje Cells: Earliest Morphological Abnormality In SCA1 Transgenic Mice.

Spinocerebellar ataxia-1 (SCA1) is caused by the expansion of a polyglutamine repeat within the disease protein, ataxin-1. The overexpression of mutant ataxin-1 in SCA1 transgenic mice results in the formation of cytoplasmic vacuoles in Purkinje neurons (PKN) of the cerebellum. PKN are closely associated with neighboring Bergmann glia. To elucidate the role of Bergmann glia in SCA1 pathogenesis, cerebellar tissue from 7 days to 6 wks old SCA1 transgenic and wildtype mice were used. We observed that Bergmann glial S100B protein is localized to the cytoplasmic vacuoles in SCA1 PKN. These S100B positive cytoplasmic vacuoles began appearing much before the onset of behavioral abnormalities, and were negative for other glial and PKN marker proteins. Electron micrographs revealed that vacuoles have a double membrane. In the vacuoles, S100B colocalized with receptors of advanced glycation end-products (RAGE), and S100B co-immunoprecipated with cerebellar RAGE. In SCA1 PKN cultures, exogenous S100B protein interacted with the PKN membranes and was internalized. These data suggest that glial S100B though extrinsic to PKN is sequestered into cytoplasmic vacuoles in SCA1 mice at early postnatal ages. Further, S100B may be binding to RAGE on Purkinje cell membranes before these membranes are internalized.

Adult onset leukodystrophy with neuroaxonal spheroids and pigmented glia: report of a family, historical perspective, and review of the literature.

We present a two-generation family consisting of a father and two daughters, who had an adult-onset leukodystrophy characterized by widespread destruction of cerebral white matter with neuroaxonal spheroids. The mode of inheritance appears to be autosomal dominant. All three patients presented with a variety of motor and cognitive symptoms, including frontal lobe signs, 4-7 years before death. Each followed a chronic course until death at ages 39, 46, and 51. At autopsy, the white matter loss was widespread but most prominent in the cerebrum with descending corticospinal tract degeneration and relative sparing of subcortical U-fibers. Pigmented glial cells were present, most of which appear to be macrophages, but inconstantly Prussian blue-positive. This disease is consistent with published reports of hereditary diffuse leukoencephalopathy with spheroids (HDLS). However, a review of the literature and a personal review of the neuropathology of the original case of the pigmentary type of orthochromatic leukodystrophy (POLD) reveal overlapping clinical and neuropathologic features between these two previously distinct entities, suggesting a common pathogenetic and perhaps etiological relationship between the two.

Spinal cord neuropathology in human West Nile virus infection.

CONTEXT: During the 1999 New York City West Nile virus (WNV) outbreak, 4 patients with profound muscle weakness, attributed to Guillain-Barré syndrome, were autopsied. These cases were the first deaths caused by WNV, a flavivirus, to be reported in the United States. The patients' brains had signs of mild viral encephalitis; spinal cords were not examined. During the 2002 national epidemic, several patients in Mississippi had acute flaccid paralysis. Electrophysiologic studies localized the lesions to the anterior horn cells in the spinal gray matter. Four of 193 infected patients in Mississippi died and were autopsied. All 4 experienced muscular weakness and respiratory failure that required intubation. Postmortem examinations focused on the spinal cord. OBJECTIVE: To emphasize apparent tropism of WNV for the ventral gray matter of the spinal cord. DESIGN: Cerebral hemispheres, basal ganglia, diencephalon, brainstem, cerebellum, and spinal cord sections were stained with hematoxylin-eosin and incubated with antibodies to T cells, B cells, and macrophages/microglial cells. RESULTS: We identified neuronophagia, neuronal disappearance, perivascular chronic inflammation, and microglial proliferation in the ventral horns of the spinal cord, especially in the cervical and lumbar segments. Loss of ganglionic neurons, nodules of Nageotte, and perivascular lymphocyte aggregates were found in dorsal root and sympathetic ganglia. Severity of cellular reaction was proportional to the interval length between patient presentation and death. CONCLUSION: West Nile virus caused poliomyelitis. Injury to spinal and sympathetic ganglia mirrored the damage to the spinal gray matter. The disappearance of sympathetic neurons could lead to the autonomic instability observed in some WNV patients, including labile vital signs, hypotension, and potentially lethal cardiac arrhythmias.