Oligodendroglioma with Neuronal Differentiation in Two Boxer Dogs

Two cases of high-grade glioma comprising sheets of oligodendroglial cells multifocally disrupted by regions of remarkable neuronal differentiation are described. These tumours morphologically resemble 'oligodendroglioma with ganglioglioma-like maturation', a rare tumour of man, but appear to be phenotypically more aggressive. Neuronal markers (synaptophysin, neuron-specific enolase and βIII-tubulin) effectively highlight neuronal elements within these tumours and could potentially help to further investigate the prevalence and biological significance of neuronal differentiation in canine oligodendroglioma.

Intracranial-derived atherosclerosis assessment: an in vitro comparison between virtual histology by intravascular ultrasonography, 7T MRI, and histopathologic findings

BACKGROUND AND PURPOSE

Atherosclerotic plaque composition and structure contribute to the risk of plaque rupture and embolization. Virtual histology by intravascular ultrasonography and high-resolution MR imaging are new imaging modalities that have been used to characterize plaque morphology and composition in peripheral arteries.

MATERIALS AND METHODS

The objectives of this study were 1) to determine the correlation between virtual histology-intravascular ultrasonography and histopathologic analysis (reference standard) and 2) to explore the comparative results of 7T MR imaging (versus histopathologic analysis), both to be performed in vitro by use of intracranial arterial segments with atherosclerotic plaques. Thirty sets of postmortem samples of intracranial circulation were prepared for the study. These samples included the middle cerebral artery (n = 20), basilar artery (n = 8), and anterior cerebral artery (n = 2). Virtual histology-intravascular ultrasonography and 7T MR imaging were performed in 34 and 10 points of interest, respectively. The formalin-fixed arteries underwent tissue processing and hematoxylin-eosin staining. The plaques were independently categorized according to revised Stary classification after review of plaque morphology and characteristics obtained from 3 modalities. The proportion of fibrous, fibrofatty, attenuated calcium, and necrotic components in the plaques were determined in histology slides and compared with virtual histology-intravascular ultrasonography and MR imaging.

RESULTS

Of 34 points of interest in the vessels, 32 had atherosclerotic plaques under direct visualization. Plaques were visualized in gray-scale intravascular ultrasonography as increased wall thickness, outer wall irregularity, and protrusion. The positive predictive value of virtual histology-intravascular ultrasonography for identifying fibroatheroma was 80%. Overall, virtual histology-intravascular ultrasonography accurately diagnosed the type of the plaque in 25 of 34 samples, and κ agreement was 0.58 (moderate agreement). The sensitivity and specificity of virtual histology-intravascular ultrasonography readings for fibroatheroma were 78.9% and 73.3%, respectively. The overall sensitivity and specificity for virtual histology-intravascular ultrasonography were 73.5% and 96.6%, respectively. Plaques were identified in 7T MR imaging as increased wall thickness, luminal stenosis, or outer wall protrusion. The positive predictive value of 7T MR imaging for detecting fibrous and attenuated calcium deposits was 88% and 93%, respectively.

CONCLUSIONS

This in vitro study demonstrated that virtual histology-intravascular ultrasonography and high-resolution MR imaging are reliable imaging tools to detect atherosclerotic plaques within the intracranial arterial wall, though both imaging modalities have some limitations in accurate characterization of the plaque components. Further clinical studies are needed to determine the clinical utility of plaque morphology and composition assessment by noninvasive tests.

Massive expansion of SCA2 with autonomic dysfunction, retinitis pigmentosa, and infantile spasms

OBJECTIVE

To provide clinical data on a cohort of 6 patients with massive expansion (>200 CAG repeats) of spinocerebellar ataxia type 2 (SCA2) and investigate possible pathways of pathogenesis using bioinformatics analysis of ATXN2 networks.

METHODS

We present data on 6 patients with massive expansion of SCA2 who presented in infancy with variable combinations of hypotonia, global developmental delay, infantile spasms, and retinitis pigmentosa. ATXN2 is known to interact with a network of synaptic proteins. To investigate pathways of pathogenesis, we performed bioinformatics analysis on ATXN2 combined with known genes associated with infantile spasms, retinitis pigmentosa, and synaptic function.

RESULTS

All patients had a progressive encephalopathy with autonomic dysfunction, 4 had retinitis pigmentosa, and 3 had infantile spasms. The bioinformatics analysis led to several interesting findings. First, an interaction between ATXN2 and SYNJ1 may account for the development of retinitis pigmentosa. Second, dysfunction of postsynaptic vesicle endocytosis may be important in children with this progressive encephalopathy. Infantile spasms may be associated with interactions between ATXN2 and the postsynaptic structural proteins MAGI2 and SPTAN1.

CONCLUSIONS

Severe phenotype in children with massive expansion of SCA2 may be due to a functional deficit in protein networks in the postsynapse, specifically involving vesicle endocytosis.

A parent advice package for family shopping trips: development and evaluation

THIS ARTICLE REPORTS ON THE PRIMARY STEPS IN THE DEVELOPMENT OF PARENT ADVICE FOR POPULAR DISSEMINATION: (a) developing advice for one specific problem situation, family shopping trips; (b) testing the advice program for benefit to children and convenience to adults; and (c) packaging the advice so it can be used successfully by interested parents. Systematic observation of 12 families using the written advice package on shopping trips revealed its effectiveness in reducing child disruptions and increasing positive interactions between parents and children. These findings, along with interview information from families, showed that the package is usable, effective, and popular with both parents and children, and thus is ready for dissemination to a wide audience of parents-a step that in itself should involve research and evaluation.

A classroom program teaching disadvantaged youths to write biographic information

Little attention has been given to how formal classroom instruction can be adapted to teach youths everyday skills such as the correct writing of biographic information frequently requested in transactions like applying for a job or a social security number and cashing a check. In this study, six youths in a special education classroom were taught to complete job application forms with the date, their name, signature, address, telephone number, date of birth, and a reference's name, address, and occupation. Each youth was trained on one item of biographic information at a time, after which he was tested on four application forms, including one on which he had not been trained. The tests show that after an item had been taught, it was correctly used in completing application forms on which the youths had been trained and forms on which they had never been trained. The study demonstrates the feasibility of teaching community-living, vocation-related skills to special-education youths in a classroom setting.

Peer tutoring among elementary students: educational benefits to the tutor

To determine whether tutoring might be academically beneficial to the tutor, this study investigated the acquisition of spelling words by three elementary students in a peer tutoring program. The experimental design allowed a simultaneous comparison of each child's gain in performance on comparable word lists on which the child tutored another child, was tutored by another child, or neither gave nor received tutoring. The children's spelling improved nearly an equivalent amount on those words on which they tutored another child as on the words on which they were tutored; no such change was noted on the words on which they neither gave nor received tutoring. These findings, that peer tutoring is profitable for the tutor as well as the tutee, provide a basis for recommending peer tutoring as one method of individualizing education.

Timeout as a punishing stimulus in continuous and intermittent schedules

The effectiveness of a brief period of isolation (timeout) in the control of disruptive behavior emitted by a retarded child in a preschool classroom setting was examined. Timeout was shown to be an effective punishing stimulus, and its control of the child's disruptive behavior was investigated under four schedules of intermittent timeout. The results suggest that as a larger percentage of responses were punished, a greater decrease in the frequency of that response occurred. This inverse relationship between the percentage of responses punished and the frequency of the response did not appear to be linear, but rather a non-linear function. This function suggests that some schedules of intermittent punishment may be as effective as continuous punishment, at least in the case of the continued suppression of a response that has already been reduced to a low frequency.

Effects of a conditioned reinforcer upon accuracy of match-to-sample behavior in pigeons

Three pigeons were trained to perform a two-key sequential match-to-sample task. During baseline conditions, food reinforcement was contingent upon the first match response to occur following 8-min periods, and orange illumination of both keys preceded the delivery of food by 0.5 sec. The baseline schedule of food reinforcement was in effect throughout the study. In some conditions, a 0.5-sec flash of orange keylight alone was presented contingent upon mismatch responses that followed variable time periods averaging 1 min. Rate of mismatch responses increased and accuracy of matching performances decreased as compared with baseline conditions. The ability of the 0.5-sec orange flash to reinforce mismatch responses was markedly reduced when it no longer immediately preceded the delivery of food.

Mouse models of human CAG repeat disorders

Expansions of CAG trinucleotide repeats encoding glutamine have been found to be the causative mutations of seven human neurodegenerative diseases. Similarities in the clinical, genetic, and molecular features of these disorders suggest they share a common mechanism of pathogenesis. Recent progress in the generation and characterization of transgenic mice expressing the genes containing expanded repeats associated with spinal and bulbar muscular atrophy (SBMA), spinocerebellar ataxia type 1 (SCA1), Machado-Joseph disease (MJD/SCA3), and Huntington's disease (HD) is beginning to provide insight into the underlying mechanisms of these neurodegenerative disorders.

A pediatric case of low-grade lymphomatoid granulomatosis presenting with a cerebellar mass

Lymphomatoid granulomatosis (LA) is a rare angiocentric lymphoreticular proliferative disease that primarily involves the lungs but may also involve extrapulmonary sites including the central nervous system, skin, and kidneys. It is rare for this condition to affect children, and presentation as a cerebellar mass is unusual. In this report, we describe a 10-year-old girl with biopsy-proved cerebellar LA.

Ganciclovir-resistant cytomegalovirus encephalitis in a bone marrow transplant recipient

A 20-year-old patient, who received a bone marrow transplant in order to treat metachromatic leukodystrophy (MLD), succumbed to cytomegalovirus (CMV) encephalitis. After CMV viremia developed, the patient received ganciclovir, but he was switched to foscarnet when ganciclovir resistance was suspected. Foscarnet was discontinued because of concern about its potential central nervous system toxicity. Autopsy samples of brain and cerebrospinal fluid contained CMV DNA with a UL97 mutation (M460V) known to confer ganciclovir resistance. No foscarnet resistance mutations were found.

Does the extent of surgery have an impact on the survival of patients who receive postoperative radiation therapy for supratentorial low-grade gliomas?

We evaluate the impact of extent of surgery (EOS) on survival of patients with supratentorial nonpilocytic low-grade gliomas (LGG) treated with postoperative radiation therapy (PORT). Sixty-five patients with pathologically confirmed supratentorial nonpilocytic LGG (36 astrocytomas and 29 oligodendrogliomas) were treated with PORT after different extents of surgery: 12 gross total resections (GTR), 27 minimal or subtotal resections (MR/SR), and 26 biopsies (B). EOS was confirmed with postoperative imaging. The median radiation dose delivered was 5,940 cGy (range, 4,950-6,620 cGy). One of 12 patients (8%) in the GTR group and 12 of 53 patients (23%) in the less than GTR group demonstrated contrast enhancement. The median follow-up was 61 months (range 5-194 month). The 10-year overall survival (OS) was 82.5% and 32% for the GTR and the less than GTR groups, respectively (P = 0.0008). The corresponding 10-year disease-specific survival (DSS) was 90% and 41.4%%, respectively (P = 0.001). Multivariate analysis showed that only contrast enhancement and EOS were predictors for OS and DSS. Our data suggest that EOS correlates with OS and DSS in patients who have PORT. GTR should be the goal if technically achievable without causing significant morbidity, and its combination with PORT is compatible with long-term survival.

Altered trafficking of membrane proteins in purkinje cells of SCA1 transgenic mice

Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disease caused by the expression of mutant ataxin-1 that contains an expanded polyglutamine tract. Overexpression of mutant ataxin-1 in Purkinje cells of transgenic mice results in a progressive ataxia and Purkinje cell pathology that are very similar to those seen in SCA1 patients. Two prominent aspects of pathology in the SCA1 mice are the presence of cytoplasmic vacuoles and dendritic atrophy. We found that the vacuoles in Purkinje cells seem to originate as large invaginations of the outer cell membrane. The cytoplasmic vacuoles contained proteins from the somatodendritic membrane, including mGluR1, GluRDelta1/Delta2, GluR2/3, and protein kinase C (PKC) gamma. Further examination of PKCgamma revealed that its sequestration into cytoplasmic vacuoles was accompanied by concurrent loss of PKCgamma localization at the Purkinje cell dendritic membrane and decreased detection of PKCgamma by Western blot analysis. In addition, the vacuoles were immunoreactive for components of the ubiquitin/proteasome degradative pathway. These findings present a link between vacuole formation and loss of dendrites in Purkinje cells of SCA1 mice and indicate that altered somatodendritic membrane trafficking and loss of proteins including PKCgamma, are a part of the neuronal dysfunction in SCA1 transgenic mice.

Reversal of increased intracranial pressure with removal of a torcular epidermoid: case report

OBJECTIVE AND IMPORTANCE

Venous obstruction has been postulated as a cause of increased intracranial pressure, but it has been documented rarely. We present a case of obstruction of the torcula by a slow-growing epidermoid. The tumor caused increased intracranial pressure, which was relieved when it was excised. In addition, the torcular epidermoid is associated with a bifid straight sinus.

CLINICAL PRESENTATION

A 35-year-old man presented with a headache and a lump on the back of the head. Physical examination revealed a firm, bony lesion approximately 4 x 4 cm in size. Lumbar puncture demonstrated an intraspinal pressure of 39 cm H2O. Neuroradiological studies revealed an epidermoid that compressed and almost completely occluded the torcula.

INTERVENTION

After the tumor was resected, the intraspinal pressure decreased to 19 cm H2O and remained stable 6 months later.

CONCLUSION

Pure venous obstruction causes increased intracranial pressure. Removal of the obstruction relieves the intracranial hypertension. In addition, computed tomographic venography is a safe and easy method of documenting torcular anatomy, and it was useful in the follow-up of this patient. Computed tomographic venography can demonstrate a double straight sinus, which is a congenital variant that may be associated with the epidermoid.

Spinocerebellar ataxia type 1--modeling the pathogenesis of a polyglutamine neurodegenerative disorder in transgenic mice

Spinocerebellar ataxia type 1 (SCA1) is one of a group of dominantly inherited neurodegenerative diseases caused by a mutant expansion of a polyglutamine-repeated sequence within the affected gene. One of the major cell types affected by the gene (ataxin-1) mutation in SCA1 is the cerebellar Purkinje cell. Targeted expression of mutant ataxin-1 in Purkinje cells of transgenic mice produces an ataxic phenotype with pathological similarities to the human disease. Other transgenic experiments using altered forms of mutant ataxin-1 have shown that nuclear localization of the mutant protein is necessary for pathogenesis and that nuclear aggregates of ubiquitinated mutant protein, while a feature of SCA1 and other polyglutamine diseases, are not a requirement for pathogenesis in transgenic models of SCA1. Present and future generations of transgenic mouse models of SCA1 will be valuable tools to further address mechanisms of pathogenesis in polyglutamine-related disorders.

Single dose versus fractionated stereotactic radiotherapy for recurrent high-grade gliomas

PURPOSE

To evaluate the efficacy of stereotactic radiotherapy (SRT) in patients with recurrent high-grade gliomas by comparing two different treatment regimens, single dose or fractionated radiotherapy.

METHODS AND MATERIALS

Between April 1991 and January 1998, 71 patients with recurrent high-grade gliomas were treated with SRT. Forty-six patients (65%) were treated with single dose radiosurgery (SRS) and 25 patients (35 %) with fractionated stereotactic radiotherapy (FSRT). For the SRS group, the median radiosurgical dose of 17 Gy was delivered to the median of 50% isodose surface (IDS) encompassing the target. For the FSRT group, the median dose of 37.5 Gy in 15 fractions was delivered to the median of 85% IDS.

RESULTS

Actuarial median survival time was 11 months for the SRS group and 12 months for the FSRT group (p = 0.3, log-rank test). Variables predicting longer survival were younger age (p = 0.006), lower grade (p = 0.0006), higher Karnofsky Performance Scale (KPS) (p = 0.0005), and smaller tumor volume (p = 0.02). Patients in the SRS group had more favorable prognostic factors, with median age of 48 years, KPS of 70, and tumor volume of 10 ml versus median age of 53 years, KPS of 60, and tumor volume of 25 ml in the FSRT group. Late complications developed in 14 patients in the SRS group and 2 patients in the FSRT group (p<0.05).

CONCLUSION

Given that FSRT patients had comparable survival to SRS patients, despite having poorer pretreatment prognostic factors and a lower risk of late complications, FSRT may be a better option for patients with larger tumors or tumors in eloquent structures. Since this is a nonrandomized study, further investigation is needed to confirm this and to determine an optimal dose/fractionation scheme.

Cyclooxygenase-2 immunoreactivity in the human brain following cerebral ischemia

The prostaglandin synthesizing enzyme cyclooxygenase-2 (COX-2) is up-regulated in the brain of rodents during cerebral ischemia and contributes to ischemic brain injury. This study sought to determine whether COX-2 is also up-regulated in the human brain in the acute stages of cerebral ischemic infarction. Paraffin-embedded sections from patients who died 1-2 days following infarction in the middle cerebral artery territory were processed for COX-2 immunohistochemistry. COX-2 immunoreactivity was observed in infiltrating neutrophils, in vascular cells and in neurons located at the border of the infarct. The data suggest that COX-2 up-regulation is also relevant to cerebral ischemia in humans and raise the possibility that COX-2 reaction products participate in the mechanisms of ischemic injury also in the human brain.

Inducible nitric oxide synthase expression in human cerebral infarcts

The inducible or "immunological" isoform of nitric oxide synthase (iNOS) is induced in many cell types by inflammatory stimuli and synthesizes toxic amounts of NO. In rodent models of focal cerebral ischemia, iNOS is expressed in neutrophils invading the injured brain and in local blood vessels. Studies with iNOS inhibitors and iNOS null mice indicate that NO produced by iNOS contributes to ischemic brain injury. In the present study, we sought to determine whether iNOS is also expressed in the human brain after ischemic stroke. Studies were conducted using immunohistochemistry on autopsy brains with neuropathological evidence of acute cerebral infarction. iNOS immunoreactivity was observed in neutrophils infiltrating the ischemic brain and in blood vessels within the ischemic territory. iNOS-positive cells also were immunoreactive for nitrotyrosine, reflecting protein nitration by NO-derived peroxynitrite and nitrites. iNOS or nitrotyrosine immunoreactivity was not detected outside the region of the infarct. These observations provide evidence that iNOS is expressed in the human brain after ischemic infarction and support the hypothesis that iNOS inhibitors may be useful in the treatment of ischemic stroke in humans.

Ataxin-1 nuclear localization and aggregation: role in polyglutamine-induced disease in SCA1 transgenic mice

Transgenic mice carrying the spinocerebellar ataxia type 1 (SCA1) gene, a polyglutamine neurodegenerative disorder, develop ataxia with ataxin-1 localized to aggregates within cerebellar Purkinje cells nuclei. To examine the importance of nuclear localization and aggregation in pathogenesis, mice expressing ataxin-1[82] with a mutated NLS were established. These mice did not develop disease, demonstrating that nuclear localization is critical for pathogenesis. In a second series of transgenic mice, ataxin-1[77] containing a deletion within the self-association region was expressed within Purkinje cells nuclei. These mice developed ataxia and Purkinje cell pathology similar to the original SCA1 mice. However, no evidence of nuclear ataxin-1 aggregates was found. Thus, although nuclear localization of ataxin-1 is necessary, nuclear aggregation of ataxin-1 is not required to initiate pathogenesis in transgenic mice.

Patient selection criteria for the treatment of brain metastases with stereotactic radiosurgery

In this study we evaluate prognostic factors that predict local-regional control and survival following stereotactic radiosurgery (SRS) in patients with brain metastasis and establish guidelines for patient selection. Our evaluation is based on 73 patients with brain metastasis treated with SRS at the University of Minnesota between March 1991 and November 1995. The ability of stereotactic radiosurgery to improve local control in patients with brain metastases is confirmed in our study in which only 6 of 62 patients failed locally after SRS, with an actuarial local progression-free survival of 80% at 2 years. Variables that predicted worse prognosis were larger tumor size (p = 0.05) for local progression-free survival and multiplicity of metastasis (p = 0.03) and infratentorial location of metastases (p = 0.006) for regional progression-free survival. Absence of extracranial disease, KPS > or = 70, and single intracranial metastasis were significant predictors of longer survival. Patients who fulfill all three criteria will survive longer after SRS (MS = 17.7 months) and will most likely benefit from the increase local control in the brain achieved by SRS. Survival in patients who do not meet any of these criteria is very poor (MS = 1.5 months), and these patients are less likely to benefit from this treatment. Careful selection of patients for SRS is warranted.

The transcription factor E2F-1 in SV40 T antigen-induced cerebellar Purkinje cell degeneration

Transgenic targeting of SV40 large T antigen (Tag) expression to murine cerebellar Purkinje cells induces these normally postmitotic neurons to undergo DNA synthesis and apoptosis. It has been proposed that these effects of Tag are due to the binding of Tag to pRb, which leads to the release and activation of the transcription factor E2F. Here it is reported that E2F and CDC2, the protein product of a gene regulated by E2F, were detectable in the Purkinje cell nuclei of Tag expressing transgenic animals. To directly test whether E2F-1 is part of the mechanism of Tag-induced Purkinje cell degeneration, transgenic mice that overexpress E2F-1 specifically in cerebellar Purkinje cells were generated. Although E2F-1 itself did not affect Purkinje cells, it did accelerate Tag-induced ataxia and Purkinje cell loss, suggesting that E2F-1 can contribute to the mechanism of Tag-induced Purkinje cell degeneration.

Cerebellar vascular and synaptic responses in normal mice and in transgenics with Purkinje cell dysfunction

We used transgenic mice with Purkinje cell dysfunction (PO3 line) to study the role of these neurons in the increase in cerebellar blood flow (BFcrb) produced by stimulation of the cerebellar parallel fibers (PF). Mice (age 8-10 wk) were anesthetized (halothane) and artificially ventilated. Arterial pressure and end-tidal CO2 were monitored continuously. Arterial blood gases were measured. The PF were stimulated electrically (100 microA, 30 Hz; 40 s), and the increases in BFcrb were monitored by a laser-Doppler flow probe. First, we characterized the increases in BFcrb and the field potentials produced by PF stimulation in normal mice. PF stimulation evoked the typical field potentials and increased BFcrb by 60 +/- 4% (100 microA, 30 Hz; n = 10). The increases in BFcrb were attenuated by the broad-spectrum glutamate receptor antagonist kynurenate (-84 +/- 3%; P < 0.05 analysis of variance; n = 5), by the DL-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)quinoxaline (-62 +/- 6%; P < 0.05; n = 5), and by the nitric oxide synthase inhibitor N omega-nitro-L-arginine (-46 +/- 7%; P < 0.05; n = 5). In PO3 transgenic mice, the increases in BFcrb produced by PF stimulation were reduced (P < 0.001) at every stimulus intensity and frequency tested (residual increase at 100 microA, 30 Hz: 19 +/- 2%; n = 6). The field potentials evoked by PF stimulation also were abnormal in that they lacked the late negative wave (n = 6), a finding consistent with lack of depolarization of Purkinje cells. The residual flow response in the transgenics was abolished by N omega-nitro-L-arginine (n = 5; P > 0.05). Ultrastructural studies showed that the density of PF-Purkinje cell synapses is reduced in PO3 mice, whereas the morphology of molecular layer interneurons (stellate cells) is normal. The findings suggest that Purkinje cells are responsible for a sizable component of the flow response whereas molecular layer interneurons mediate the remainder of the response. The study provides evidence that mouse mutants with spontaneous or genetically engineered cerebellar abnormalities could be useful to study the cellular and molecular correlates of functional hyperemia in the central nervous system.

Spinocerebellar ataxia type 6: gaze-evoked and vertical nystagmus, Purkinje cell degeneration, and variable age of onset

Spinocerebellar ataxia type 6 (SCA6) was recently identified as a form of autosomal dominant cerebellar ataxia associated with small expansions of the trinucleotide repeat (CAG)n in the gene CACNL1A4 on chromosome 19p13, which encodes the alpha1 subunit of a P/Q-type voltage-gated calcium channel. We describe clinical, genetic, neuroimaging, neuropathological, and quantitative oculomotor studies in four kindreds with SCA6. We found strong genetic linkage of the disease to the CACNL1A4 locus and strong association with the expanded (CAG)n alleles in two large ataxia kindreds. The expanded alleles were all of a single size (repeat number) within the two large kindreds, numbering 22 and 23 repeat units. It is noteworthy that the age of onset of ataxia ranged from 24 to 63 years among all affected individuals, despite the uniform repeat number. Radiographically and pathologically, there was selective atrophy of the cerebellum and extensive loss of Purkinje cells in the cerebellar cortex. In addition, clinical and quantitative measurement of extraocular movements demonstrated a characteristic pattern of ocular motor and vestibular abnormalities, including horizontal and vertical nystagmus and an abnormal vestibulo-ocular reflex. These studies identify a distinct phenotype associated with this newly recognized form of dominant SCA.

Purkinje cell expression of a mutant allele of SCA1 in transgenic mice leads to disparate effects on motor behaviors, followed by a progressive cerebellar dysfunction and histological alterations

Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurological disorder caused by the expansion of a CAG repeat encoding a polyglutamine tract. Work presented here describes the behavioral and neuropathological course seen in mutant SCA1 transgenic mice. Behavioral tests indicate that at 5 weeks of age mutant mice have an impaired performance on the rotating rod in the absence of deficits in balance and coordination. In contrast, these mutant SCA1 mice have an increased initial exploratory behavior. Thus, expression of the mutant SCA1 allele within cerebellar Purkinje cells has divergent effects on the motor behavior of juvenile animals: a compromise of rotating rod performance and a simultaneous enhancement of initial exploratory activity. With age, these animals develop incoordination with concomitant progressive Purkinje neuron dendritic and somatic atrophy but relatively little cell loss. Therefore, the eventual development of ataxia caused by the expression of a mutant SCA1 allele is not the result of cell death per se, but the result of cellular dysfunction and morphological alterations that occur before neuronal demise.

Gerstmann-Sträussler-Scheinker disease with the PRNP P102L mutation and valine at codon 129

The most common mutation causing Gerstmann-Sträussler-Scheinker (GSS) disease is P102L in the prion protein. Previously, this mutation has only been found in coupling with methionine at residue 129. We describe a patient with GSS disease in whom the P102L mutation is in coupling with valine at residue 129. The clinical presentation in P102L-V129 differs greatly from that seen in P102-M129 patients.

Susceptibility to cell death induced by mutant SV40 T-antigen correlates with Purkinje neuron functional development

Purkinje cells are uniquely susceptible to a number of physical, chemical, and genetic insults both during development and in the mature state. We have previously shown that when the postmitotic state of murine Purkinje cells is altered by inactivation of the retinoblastoma tumor susceptibility protein (pRb), immature as well as mature Purkinje cells undergo apoptosis. DNA synthesis and neuronal loss are induced in postmitotic Purkinje cells dependent upon the pRb-binding portion of SV40 large T antigen (T-ag). In the present study, Purkinje cell targeting of a mutant T-ag, PVU, which does not bind pRb, reveals disparate cerebellar phenotypes dependent upon temporal differences in transgene expression. Strong embryonic and postnatal transgene expression in three lines alters Purkinje cell development and function during the second postnatal week, causing ataxia without Purkinje cell loss. In contrast, two other transgenic lines reveal that PVU T-ag expression following normal Purkinje cell maturation causes rapid Purkinje cell degeneration. The second and third postnatal weeks of cerebellar development, which include the major period of synaptogenesis, appear to be the defining stage for the two PVU-induced phenotypes. These data indicate that Purkinje cell death susceptibility varies with developmental stage.

Inducible nitric oxide synthase gene expression in vascular cells after transient focal cerebral ischemia

BACKGROUND AND PURPOSE

We investigated whether inducible nitric oxide synthase (iNOS) is expressed after transient cerebral ischemia and, if so, we sought to define the temporal profile and cellular localization of the expression and the role of iNOS in the mechanism of ischemic brain injury.

METHODS

The middle cerebral artery in rats was occluded for 2 hours by an intraluminal filament. The occurrence of transient ischemia and reperfusion was confirmed by laser-Doppler flowmetry (n = 5). iNOS message in the ischemic neocortex was determined by reverse-transcription polymerase chain reaction. iNOS enzymatic activity was assessed by citrulline assay. The cellular localization of iNOS expression was determined by immunohistochemistry.

RESULTS

iNOS mRNA was maximally expressed in postischemic brain at 12 hours and was not present at 4 days (n = 3 per time point). iNOS mRNA was not observed in the contralateral cerebral cortex. iNOS enzymatic activity developed in the postischemic brain between 12 and 24 hours (P < .05) and subsided at 4 days (n = 4 to 8 per time point). iNOS immunoreactivity in the ischemic region was restricted to the wall of capillaries and of larger blood vessels at 12 to 24 hours. In regions of early necrosis, inflammatory cells were iNOS positive. Treatment with the iNOS inhibitor aminoguanidine (n = 5; 100 mg/kg IP, BID for 4 days), starting 6 hours after ischemia, reduced infarct size in neocortex by 36 +/- 7% in comparison with vehicle-treated controls (n = 5) (P < .05).

CONCLUSIONS

Transient focal ischemia leads to iNOS expression in postischemic brain. However, the spatial and temporal patterns of expression differ from those occurring in permanent ischemia: iNOS is induced earlier and predominantly in vascular cells rather than in neutrophils. Thus, the temporal profile and localization of postischemic iNOS expression depend on the nature of the ischemic insult. The finding that aminoguanidine reduces infarct size adds further support to the hypothesis that postischemic iNOS expression contributes to ischemic brain damage.

Somatic mosaicism in the central nervous system in spinocerebellar ataxia type 1 and Machado-Joseph disease

Spinocerebellar ataxia type 1 and Machado-Joseph disease are two autosomal dominant cerebellar ataxias caused by expansions of unstable CAG repeats in the coding region of the causative genes. The selectivity of cell death and the resulting characteristic neuropathological features in each of these diseases are not explained by the gene expression patterns. Since the repeat size correlates with age at onset and severity of these diseases, somatic mosaicism, the result of mitotic instability of the CAG repeat, could be the basis for specificity of neurodegeneration; brain structures with larger expanded repeats would be more severely affected. To study the association between neuropathological changes and somatic mosaicism of the CAG repeat size in the central nervous system of patients with these two ataxias, we determined the size of the (CAG)n expansion in 20 different regions of the brain, brainstem, cerebellum, and spinal cord from 3 patients with spinocerebellar ataxia type 1 and 3 with Machado-Joseph disease; these regions were selected for their differential neuropathological involvement in the two disorders. We observed a considerable homogeneity of repeat size ranges in all but 1 of the 20 regions examined: The cerebellar cortex showed slightly smaller (CAG)n tracts in all specimens from both groups of patients. Our results suggest that the pattern of repeat size mosaicism, similar in spinocerebellar ataxia type 1 and Machado-Joseph disease, reflects the developmental pathways and cell composition of different central nervous system regions and is not the cause of selective cell death in these disorders.

Heat shock proteins and experimental autoimmune encephalomyelitis (EAE): I. Immunization with a peptide of the myelin protein 2',3' cyclic nucleotide 3' phosphodiesterase that is cross-reactive with a heat shock protein alters the course of EAE

We describe sequence similarity and immunologic cross-reactivity between a peptide of the mycobacterial hsp, HSP65, and the myelin protein 2',3' cyclic nucleotide 3' phosphodiesterase (CNP). We demonstrate that immunization with the homologous cross-reactive CNP peptide (hsp-CNP peptide) has significant biological consequences. Rats immunized with hsp-CNP peptide in either complete Freund's adjuvant (CFA) or incomplete Freund's adjuvant (IFA) produce large amounts of peptide-specific antibody. Isotypes of antibodies in animals immunized with peptide in CFA are IgG1 and IgG2a. Isotypes of antibodies in rats immunized with peptide in IFA are predominantly IgG1, with low titers of IgG2a. T cell proliferative responses to HSP65 are present in rats immunized with peptide in CFA. T cell responses to HSP65 initially are absent in rats immunized with peptide in IFA but develop over time. T cell proliferative responses to hsp-CNP peptide were not detected. None of the groups of rats developed clinical or histologic evidence of experimental autoimmune encephalomyelitis (EAE). To induce EAE, rats preimmunized with hsp-CNP peptide were challenged with guinea pig spinal cord (GPSC) emulsified in CFA. Rats preimmunized with peptide in CFA developed severe EAE. Rats preimmunized with hsp-CNP peptide in IFA were protected from EAE, with both a lower incidence and severity of disease. Injecting the murine monoclonal antibody recognizing the shared HSP65 and CNP epitope did not protect against EAE. Our data suggest that a Th2 pattern of immune response to a CNP peptide that itself is non-encephalitogenic protects against EAE. Immune responses to either hsp or myelin proteins cross-reactive with hsp may play an important role in the development of EAE.

A beta-associated cerebral angiopathy and senile plaques with neurofibrillary tangles and cerebral hemorrhage in an aged wolverine (Gulo gulo)

In this study of an aged wolverine (Gulo gulo), we document neuropathologic lesions (cerebral amyloid angiopathy (CAA), neuritic plaques (NPs), neurofibrillary tangles (NFTs), and granulovacuolar degeneration strikingly similar to those present in aging and Alzheimer's disease (AD), with the additional finding of concurrent cerebral hemorrhage. A beta immunoreactive cerebral amyloid angiopathy and senile plaques (neuritic and diffuse) were present throughout the cerebral cortex and hippocampus. Ubiquitin immunoreactivity was noted in peripheral portions of some of the plaques. Argyrophilic intracellular neurofibrillary tangles containing abnormally phosphorylated (Ser 202) tau protein were present within cortical and hippocampal neurons. The wolverine should be added to the list of nonhuman species (dogs, nonhuman primates, polar bears) with amyloid deposits similar to those in aged humans and in humans with AD. The aged wolverine appears to be distinct from other nonhuman species in possessing plaques and NFTs, as well as other histologic cerebral lesions frequently associated with AD.

The impact of intensive case-managed intervention on substance-using pregnant and postpartum women

This study examines the impact of the Women's Intervention Services and Education (WISE) Project in serving substance-using pregnant and postpartum women through an array of case-managed services and supports. A descriptive analysis of multiple outcome indicators was performed on 152 women who had a minimum 6 months of exposure to WISE services at the time of the analysis. The variables used in the analysis to assess client and program outcomes included substance use, employment, arrests, incarceration, birthweight, and social support. This group of women showed statistically significant improvements across each of these multiple outcome indicators from pre-WISE to WISE discharge. Although the findings of this study are not conclusive because no control group was employed, the results are encouraging and supportive of a growing body of literature that suggests that pregnant and postpartum polydrug-using women can be responsive to case-managed, intensive intervention, with aftercare support.

Middle cerebral artery dissection: a clinicopathologic study

We present a case report of a 17-year-old young man who developed fatal dissection of the middle cerebral artery after what appeared to be trivial trauma. The dissection was not evident on cerebral arteriogram but was identified at autopsy. Arterial dissection should be considered in the differential diagnosis of supraclinoid occlusion of the internal carotid artery seen by cerebral angiography.

SCA1 transgenic mice: a model for neurodegeneration caused by an expanded CAG trinucleotide repeat

Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant inherited disorder characterized by degeneration of cerebellar Purkinje cells, spinocerebellar tracts, and selective brainstem neurons owing to the expansion of an unstable CAG trinucleotide repeat. To gain insight into the pathogenesis of the SCA1 mutation and the intergenerational stability of trinucleotide repeats in mice, we have generated transgenic mice expressing the human SCA1 gene with either a normal or an expanded CAG tract. Both transgenes were stable in parent to offspring transmissions. While all six transgenic lines expressing the unexpanded human SCA1 allele had normal Purkinje cells, transgenic animals from five of six lines with the expanded SCA1 allele developed ataxia and Purkinje cell degeneration. These data indicate that expanded CAG repeats expressed in Purkinje cells are sufficient to produce degeneration and ataxia and demonstrate that a mouse model can be established for neurodegeneration caused by CAG repeat expansions.

Multifocal enhancing magnetic resonance imaging lesions following cranial irradiation

Radiation necrosis is a delayed complication of cranial irradiation, typically presenting as a single intracerebral mass that is radiographically indistinguishable from recurrent tumor. We describe 6 patients with a distinct radiographic syndrome of multifocal enhancing lesions on magnetic resonance images, and their variable clinical courses: some fluctuating, some spontaneously resolving, and some demonstrating fulminant progression to frank necrosis.

Stereotactic radiosurgery for recurrent malignant gliomas

PURPOSE

To evaluate the role of stereotactic radiosurgery in the management of recurrent malignant gliomas.

PATIENTS AND METHODS

We treated 35 patients with large (median treatment volume, 28 cm3) recurrent tumors that had failed to respond to conventional treatment. Twenty-six patients (74%) had glioblastomas multiforme (GBM) and nine (26%) had anaplastic astrocytomas (AA).

RESULTS

The mean time from diagnosis to radiosurgery was 10 months (range, 1 to 36), from radiosurgery to death, 8.0 months (range, 1 to 23). Twenty-one GBM (81%) and six AA (67%) patients have died. The actuarial survival time for all patients was 21 months from diagnosis and 8 months from radiosurgery. Twenty-two of 26 patients (85%) died of local or marginal failure, three (12%) of noncontiguous failure, and one (4%) of CSF dissemination. Age (P = .0405) was associated with improved survival on multivariate analysis, and age (P = .0110) and Karnofsky performance status (KPS) (P = .0285) on univariate analysis. Histology, treatment volume, and treatment dose were not significant variables by univariate analysis. Seven patients required surgical resection for increasing mass effect a mean of 4.0 months after radiosurgery, for an actuarial reoperation rate of 31%. Surgery did not significantly influence survival. At surgery, four patients had recurrent tumor, two had radiation necrosis, and one had both tumor and necrosis. The actuarial necrosis rate was 14% and the pathologic findings could have been predicted by the integrated logistic formula for developing symptomatic brain injury.

CONCLUSION

Stereotactic radiosurgery appears to prolong survival for recurrent malignant gliomas and has a lower reoperative rate for symptomatic necrosis than does brachytherapy. Patterns of failure are similar for both of these techniques.

In vivo viability of postmitotic Purkinje neurons requires pRb family member function

The product of the retinoblastoma susceptibility gene, pRb, is known to be an important regulator of cell division. Disrupted central nervous system development in RB null mice suggests a critical function for pRb in the proliferative arrest and initiation of terminal differentiation of certain neurons. Previously, we have shown that SV40 T-ag expression targeted to Purkinje neurons in transgenic mice causes cell-specific death. Here we describe that T-ag expression induces DNA synthesis and results in DNA fragmentation in Purkinje neurons. Characterization of transgenic mouse lines expressing mutant T-ags demonstrate that the pRb binding domain of T-ag is required for induction of Purkinje cell loss. These findings indicate that a pRb function is required well beyond the completion of Purkinje neuron differentiation and provide a link between cell cycle regulation and neurodegeneration in vivo.

Sneddon's syndrome with granulomatous leptomeningeal infiltration

BACKGROUND

There is limited neuropathologic information available from cases of Sneddon's syndrome in which strokes are associated with livedo reticularis. Pathogenesis of the syndrome is controversial, although current opinion favors a coagulopathy, often with antiphospholipid antibodies. We describe a case lacking antiphospholipid antibodies but having a granulomatous infiltration of the leptomeninges.

CASE DESCRIPTION

The patient presented at age 29 with stroke, livedo reticularis, essential hypertension, and Raynaud's phenomenon. Assessment uncovered no underlying disease, including absent antiphospholipid antibodies. A leptomeningeal biopsy showed granulomatous infiltration.

CONCLUSIONS

The findings suggest that an inflammatory process plays a role in at least some cases of Sneddon's syndrome.

Sacrococcygeal chordoma metastatic to the brain with review of the literature

A 29-year-old man presented with headache, confusion, word-finding difficulty, and a visual field deficit 16 months after complete removal of a sacrococcygeal chordoma. Magnetic resonance imaging of the head demonstrated two discrete enhancing left occipital lesions with associated cerebral edema. Both masses were surgically excised and their histological appearance was consistent with chordoma. Chordoma from the sacral region is known to metastasize to the lungs and the vertebral bodies but has rarely been shown to spread to the brain. Dissemination to the brain in this case may be related to the extent of the metastatic pulmonary disease and the anaplastic appearance of the primary tumor.

Case management of pregnant and parenting female crack and polydrug abusers

The increasing use of crack-cocaine among addicted women and subsequent births of polydrug-exposed infants prompted the State of Florida to undertake initiatives to seek solutions to these problems. This study, focused on one of these initiatives, explored the relationship between service components of a comprehensive treatment program and substance-free time among 120 African American and Caucasian crack-cocaine addicted women. Findings from a multiple regression analysis indicated that aftercare management (p < .0001), vocational services (p < .02), and residential treatment (p < .03) were statistically significant services associated with substance-free time. Although these findings are not conclusive, they are supportive of a growing body of literature that suggests that crack-using and polydrug-using women can be responsive to treatment when it is tailored to their individual needs and includes long-term community support.

Peer support group for adolescents with chronic illness

This study assessed the effects of a monthly peer support group for adolescents with cancer and other hematological diseases. These adolescents shared activities and experiences with nondisabled high school students. At the group's conclusion, the adolescents reported that the group helped them cope with their illness and improved the quality of their daily lives. Nondisabled students reported that the group favorably affected their attitudes about, and intended behavior toward, peers with chronic illnesses. These results suggest that such groups can provide important benefits for individuals with chronic illnesses as well as for their nondisabled peers.

Disrupted cerebellar cortical development and progressive degeneration of Purkinje cells in SV40 T antigen transgenic mice

SV40 T antigen (Tag) expression directed to cerebellar Purkinje cells resulted in the generation of three transgenic mouse lines that displayed ataxia, a neurological phenotype characteristic of cerebellar dysfunction. Onset of symptoms and cerebellar pathology, characterized by specific Purkinje cell degeneration, appeared to be directly dependent upon transgene copy number. The SV5 line (containing > 30 transgene copies), exhibited embryonic transgene expression that caused selective death of immature Purkinje cells and a subsequent block in cerebellar development and ataxia at 2 weeks. The developmental effect of the disruption of Purkinje cells in SV5 mice suggests that a normal complement of these cells is required for early development of the cerebellar cortex, especially granule cell proliferation and migration from external to internal layers. Transgene expression in a second line, SV4 (10 copies), was detectable during the second postnatal week. Death of mature Purkinje cells in the SV4 line resulted in onset of ataxia at 9 weeks. Ataxia in a third line, SV6 (2 copies), was detected after 15 weeks. The distinct cerebellar phenotypes of the SV4-6 lines correlate with specific Tag-induced Purkinje cell ablation as opposed to tumorigenesis.

Metastatic carcinoid tumor to the orbit and brain

Carcinoid tumors constitute an uncommon source of metastatic lesions to the brain. We report the case of a 63-year-old man who initially sought treatment for proptosis 15 years before coming to our attention with a metastatic intracerebral left parietal carcinoid. The pathological features of the exenterated orbital mass were interpreted as undifferentiated carcinoma, and a lesion of the left lower lobe of the lung that had been removed 6 years earlier had been reported as metastatic malignant melanoma. The long duration between the initial diagnosis and the onset of neurological symptoms brought into question the original diagnosis, which, in retrospect, was most consistent with metastatic carcinoid. Staining for cytokeratin, neuron-specific enolase, and synaptophysin in the absence of staining for S-100 and HMB-45 supported the revised pathological diagnosis. Metastatic intracerebral carcinoid from an unrecognized bronchogenic source is a rare event, particularly after an orbital metastasis, but should be suspected when the clinical course is inconsistent with the more common causes of metastatic disease.

Olfactory bulb lesions in Alzheimer's disease

The olfactory bulb (OB), with its comparatively simple and well-delineated connectivity, presents an interesting system for examining cell-specific pathology in neurologic degenerative disorders such as Alzheimer's disease (AD). We have found that in AD the large, efferently projecting neurons (mitral cells) of the OB degenerate, typically without classical Alzheimer neurofibrillary changes. In some cases, with less severe neocortical pathology, the terminal arborizations of olfactory nerve appear hyperplastic and are associated with focal accumulations of A-4 (beta-amyloid) immunoreactivity that are not detectable by standard amyloid stains. These abnormalities may represent a pathologic manifestation of normally occurring plasticity in the olfactory system.

Preventing relapse in obesity through posttreatment maintenance systems: comparing the relative efficacy of two levels of therapist support

The present study compared the relative effectiveness of a therapist-supported maintenance condition with a minimal contact maintenance condition in preventing relapse following an obesity treatment program. Thirty-two subjects who completed an initial 12-week cognitive/behavioral plus aerobic exercise treatment program were matched on absolute weight loss and randomly assigned to one of two maintenance conditions. Subjects were assessed at pretreatment, posttreatment, and 3, 6, and 12 months following posttreatment using measures of weight, blood pressure, and depression. Three- and six-month follow-up results indicated that subjects who participated in the therapist-supported maintenance group continued to lose weight and/or maintained therapy-induced weight loss to a greater degree than control subjects. At the 12-month follow-up assessment therapist-supported subjects maintained therapy-induced weight loss better than the control subjects. These findings suggest that maintenance programs which provide continued contact emphasizing relapse prevention training may be an important adjunct in the maintenance of therapy-induced weight loss.

Nerve growth factor receptor in neural lobe of rat pituitary gland: immunohistochemical localization, biochemical characterization and regulation

Nerve growth factor-receptor immunoreactivity was detected in the neural lobe of the pituitary gland in developing and adult rats of both sexes. The presence of nerve growth factor receptor in the neural lobe was further verified by a quantitative 125I-nerve growth factor/crosslink/immunoprecipitation assay and subsequent visualization by SDS-PAGE autoradiography. Nerve growth factor-receptor immunoreactivity was detected in the neural lobe of postnatal 5-day-old rats, had increased by 2 months and was much higher in 1-year-old rats. In 2-month-old rats, no immunoreactivity was observed in anterior or intermediate lobes. Pituitary stalk transection in young adult rats greatly increased the expression of nerve growth factor-receptor immunoreactivity in the neural lobe, although the staining pattern remained the same. This increase began 3 days after surgery, and reached peak levels at approximately 15 days. Other physiological or non-physiological changes did not alter the nerve growth factor-receptor immunoreactivity in the neural lobe; these changes included dehydration, pregnancy and lactation, castration of male rats, bilateral superior cervical ganglionectomy and intraventricular injection of colchicine. Intravenously injected 125I-nerve growth factor was specifically accumulated in both normal and denervated neural lobe. Nerve growth factor-receptor immunohistochemical electron microscopy showed that the receptor-positive cells are fusiform and found both inside and outside the basal lamina that delimits the neural lobe parenchyma. Based upon the anatomical localization, morphology and response to axotomy, we identify, at least the perivascular component, as microglia. These data suggest a role for nerve growth factor and/or nerve growth factor receptor in microglial function.