December 2004: one-year-old girl with aggressive skull tumor

December 2004. Twelve-month old girl presented with recurrent subcutaneous lesion in the left parietal region, one year after excision of a "benign" tumor. An MRI demonstrated left temporo-parietal skull tumor infiltrating the soft tissue, surrounding craniotomy flap, and extending to the brain parenchyma. Biopsy revealed biphasic neoplasm displaying nests of poorly differentiated neuroblastic cells positive for synaptophysin and pigmented cuboidal epithelioid cell positive for keratins, epithelial membrane antigen and MHB-45. In addition, some neoplastic cells were immunoreactive for synaptophysin as well as HMB-45 and epithelial markers, suggestive of their origin from a common progenitor. Interestingly, cell with the neuroblastic immunophenotype displayed 80% nuclear MIB-1 reactivity indicating that the aggressiveness of the neoplasm was confined mostly to this pattern of differentiation. The overall histological features are consistent with a rare malignant variant of a melanotic neuroectodermal tumor of infancy.

Intracerebral rhabdoid and papillary meningioma with leptomeningeal spread and rapid clinical progression

OBJECTIVE AND IMPORTANCE

Rhabdoid meningioma (RM) is a relatively new, Grade III tumor entity according to the latest WHO classification. We report rhabdoid and partly papillary, highly anaplastic, intracerebral meningioma with diffuse leptomeningeal spread and distant SCF metastasis to the cervical cord.

CLINICAL PRESENTATION

This 27-year-old female was admitted to the hospital with radiological findings suggestive of a primary brain tumor or a metastasis. After subtotal resection and during radiotherapy, follow-up MRI revealed recurrence, metastasis to meninges at the high cervical level, and diffuse basal leptomeningeal enhancement indicating infiltrating tumor. She died approximately 3 months after onset of symptoms.

RESULTS

Histological examination revealed rhabdoid and papillary meningioma with high proliferation rate (80% of MIB1-positive cells), necrosis and extensive brain invasion. It was positive for vimentin and S-100 protein, showed focal epithelial membrane antigen expression and accumulation of intermediate filaments on ultrastructural examination. The recurrent tumor diffusely infiltrated leptomeninges and subarachnoid space.

CONCLUSION

This is a rare example of mixed, rhabdoid and papillary variant of meningioma, located entirely within the brain parenchyma and accompanied by a fulminant clinical course. The combination of the histological anaplasia with the highest reported proliferation rate, and loss of the cohesion of neoplastic cells led to diffused infiltration of the leptomeninges and metastasis to the spinal cord.

Inflammatory, hemostatic, and clinical changes in a baboon experimental model for heatstroke

The mortality and neurological morbidity in heatstroke have been attributed to the host's inflammatory and hemostatic responses to heat stress, suggesting that immunomodulation may improve outcome. We postulated that an experimental baboon model of heatstroke will reproduce human responses and clinical outcome to allow testing of new therapeutic strategies. Eight anesthetized juvenile baboons (Papio hamadryas) were subjected to heat stress in an incubator maintained at 44-47 degrees C until rectal temperature attained 42.5 degrees C (moderate heatstroke; n = 4) or systolic arterial pressure fell to <90 mmHg (severe heatstroke; n = 4) and were allowed to recover at room temperature. Four sham-heated animals served as a control group. Rectal temperature at the end of heat stress was 42.5 +/- 0.0 and 43.3 +/- 0.1 degrees C, respectively. All heat-stressed animals had systemic inflammation and activated coagulation, indicated by increased plasma IL-6, prothrombin time, activated partial thromboplastin time, and D-dimer levels, and decreased platelet count. Biochemical markers and/or histology evidenced cellular injury/dysfunction: plasma levels of thrombomodulin, creatinine, creatine kinase, lactic dehydrogenase, and alanine aminotransferase were increased, and varying degrees of tissue damage were present in liver, brain, and gut. No baboon with severe heatstroke survived. Neurological morbidity but no mortality was observed in baboons with moderate heatstroke. Nonsurvivors displayed significantly greater coagulopathy, inflammatory activity, and tissue injury than survivors. Sham-heated animals had an uneventful course. Heat stress elicited distinct patterns of inflammatory and hemostatic responses associated with outcome. The baboon model of heatstroke appears suitable for testing whether immunomodulation of the host's responses can improve outcome.

Mutation of the slow myosin heavy chain rod domain underlies hyaline body myopathy

OBJECTIVE

To identify the gene and specific mutation underlying hyaline body myopathy in the family studied.

METHODS

A microsatellite-based whole genome scan was performed. Linkage analysis assumed autosomal dominant inheritance and equal allele frequencies. A candidate gene approach within the linked interval and direct sequencing were used for mutation detection.

RESULTS

Initial analysis indicated a maximum lod score of 3.01 at D14S1280. High-density mapping surrounding the linked locus was performed. Multipoint analysis showed that the linked region with a maximum lod score of 3.01 extended from D14S742 to D14S608 with a peak non-parametric linkage (NPL) score of 3.75 at D14S608. The myosin heavy chain genes MYH6 and MYH7 map to the region between D14S742 and D14S1280. Sequence analysis of the coding regions of MYH7 revealed an A-->T transversion at nucleotide position 25596 (M57965) resulting in a histidine-to-leucine amino acid change at residue 1904 (H1904L).

CONCLUSION

Pathogenicity of the MYH7 H1904L mutation most likely results from disruption of myosin heavy chain assembly or stability of the sarcomeric protein. The MYH7 tail domain mutation results in an inclusion body myopathy with an apparent absence of hypertrophic cardiomyopathy usually associated with mutations of this gene.

Spontaneous anaplasia in pilocytic astrocytoma of cerebellum

We report a cystic cerebellar astrocytoma with a mural nodule that contained an additional focus of astrocytoma with the histological features of anaplasia, and showed up to 48% of aneuploid and 3% S-phase cells on flow cytometry. This focus was detectable on the enhanced, as well as non-enhanced T1 and T2 images. This appears to be the first case of pilocytic astrocytoma of cerebellum with focal anaplasia detected on histological and radiological studies.

Autosomal dominant hyaline body myopathy: Clinical variability and pathologic findings

OBJECTIVE

To report clinical, morphologic, and immunohistochemical studies on autosomal dominant, clinically nonprogressive, and not previously described progressive forms of hyaline body (HB) myopathy (HBM) in a Saudi Arabian kindred.

RESULTS

Muscle biopsies from four patients showed HB in type 1 fibers; they were positive for ATPase at pH 4.3/4.6 and for heavy chain slow myosin (HCSM); some HB were HCSM negative. HB were nonreactive for alphaB-crystallin, ubiquitin, tropomyosin, actins, desmin, and components of sarcolemma. Ultrastructurally, HB were granular and filamentous or amorphous, often with fragments of sarcomeres, and surrounded by a zone of sarcomeric disorganization. All biopsies showed "myopathic" changes, angulated neurogenic fibers, and fiber type grouping. There was no correlation between HB and course of disease; the progressive cases displayed more severe myopathic features.

CONCLUSIONS

Formation of hyaline bodies in hyaline body myopathy is associated with either myolysis or defective incorporation of heavy chain slow myosin into the cytoskeleton. Hyaline bodies very likely contain additional unidentified proteins. Neurogenic factors are also involved in the hyaline body myopathy pathogenesis.

Selective vulnerability of the lumbosacral spinal cord after cardiac arrest and hypotension

BACKGROUND AND PURPOSE

It is generally accepted that the gray matter in the watershed area of the midthoracic level of the spinal cord is the ischemic watershed zone of the spinal cord. We performed a retrospective study to reevaluate the frequency and distribution of spinal cord injury after a global ischemic event.

METHODS

Clinical files and neuropathology specimens of all adult patients with either a well-documented cardiac arrest or a severe hypotensive episode, as well as pathologically confirmed ischemic encephalopathy and/or myelopathy, were reviewed by an independent reviewer.

RESULTS

Among 145 cases satisfying selection criteria, ischemic myelopathy was found in 46% of patients dying after either a cardiac arrest or a severe hypotensive episode. Among the patients with myelopathy, predominant involvement of the lumbosacral level with relative sparing of thoracic levels was observed in >95% of cardiac arrest and hypotensive patients. None of the examined patients developed neuronal necrosis limited to the thoracic level only.

CONCLUSIONS

Our findings indicate a greater vulnerability of neurons in the lumbar or lumbosacral spinal cord to ischemia than other levels of the spinal cord.

Metastatic calcification of the cardiac conduction system with heart block: an under-reported entity in chronic renal failure patients

Systemic metastatic calcification is a common complication of chronic renal failure. Cardiac involvement is particularly ominous, especially when the cardiac conduction system is affected. Conduction defects, arrhythmias, and sudden death have all been reported with conduction system calcification; however, these are relatively under-reported or unrecognized causes of cardiac morbidity and mortality. We describe a 40-year-old man with Von Hippel-Lindau disease who had been maintained on hemodialysis for two years following bilateral nephrectomies for renal cell carcinoma. The patient presented with symptomatic complete heart block that had progressed from Mobitz type I atrioventricular block. Two months later, while being internally paced, the patient died unexpectedly after a complicated hospital admission. Postmortem revealed extensive vascular, myocardial, and conduction system calcification. Conduction system calcification may cause sudden death in chronic renal failure patients during hospital admission, or unexpectedly while the patient is in the community. Knowledge of this condition is necessary to detect it, as the conduction system is not routinely examined. A routine abbreviated conduction system examination is warranted for patients with systemic metastatic calcification, especially if they have sudden death or a known history of heart block.

Microglia cells are the driving force in fibrillar plaque formation, whereas astrocytes are a leading factor in plague degradation

Ultrastructural three-dimensional reconstruction of human classical plaques in different stages of development shows that microglial cells are the major factor driving plaque formation by fibrillar amyloid-beta (Abeta) deposition. The amount of fibrillar Abeta released by microglial cells and the area of direct contact between amyloid and neuron determine the extent of dystrophic changes in neuronal processes and synapses. The volume of hypertrophic astrocytic processes separating fibrillar amyloid from neuron is a measure of the protective activation of astrocytes. On the bases of the volume of amyloid star, microglial cells, dystrophic neurites, and hypertrophic astrocytic processes, and spatial relationships between plaque components, three stages in classical plaque development have been distinguished: early, mature, and late. In early plaque, the leading pathology is fibrillar Abeta deposition by microglial cells with amyloid star formation. The mature plaque is characterized by a balance between amyloid production, neuronal dystrophy, and astrocyte hypertrophy. In late classical plaque, microglial cells retract and expose neuropil on direct contact with amyloid star, enhancing both dystrophic changes in neurons and hypertrophic changes in astrocytes. In late plaques, activation of astrocytes predominates. They degrade amyloid star and peripheral amyloid wisps. The effect of these changes is classical plaque degradation to fibrillar primitive and finally to nonfibrillar, diffuse-like plaques.

Primary composite angiogenic leiomyosarcoma-epithelioid angiosarcoma of the brain

The authors describe a primary sarcoma of the brain with immunohistochemical and ultrastructural features of leiomyosarcoma as well as epithelioid hemangiosarcoma. The leiomyosarcomatous component consisted of spindle cells with well-developed external lamina, subsarcolemmal densities composed of microfilaments, pinocytic vesicles, and abundant intermediate filaments, and showed immunohistochemical reactions for smooth muscle actin. The epithelioid part of the tumor contained scattered cells reactive for alkaline phosphatase as well as CD31 and factor VIII. Many epithelioid cells were lipidized and remarkably similar to "stromal cells" of a hemangioblastoma. Occasional Weibel-Palade bodies, indicating endothelial differentiation, were present in scattered neoplastic cells. There were also cells with features intermediate between endothelium, pericytes and smooth muscle cells, and undifferentiated mesenchymal cells. The brain at the periphery of sarcoma showed conglomerates of well-differentiated capillaries, telangiectasias and small dysplastic arteries, features that raise the possibility of origin of this tumor from a preexisting vascular developmental abnormality.

Lumbar radiculopathy secondary to gouty tophi in the filum terminale in a patient without systemic gout: case report

OBJECTIVE AND IMPORTANCE

Gouty arthritis and gouty tophi of the spine are very rare. We present a patient with the clinical manifestations of an intradural tumor and histologically proven gouty deposits in the filum terminale.

CLINICAL PRESENTATION

The patient presented with typical symptoms of lumbar radiculopathy and neurogenic claudication. There was no evidence of peripheral gout.

INTERVENTION

Imaging studies, including computed tomography and magnetic resonance imaging, demonstrated a 1-cm, round, intradural, calcified lesion at the L3 vertebral level, causing moderate spinal stenosis. The patient underwent a two-level laminectomy and removal of the mass. A pathological examination of the specimen revealed gouty deposits in the region of the filum terminale.

CONCLUSION

Spinal involvement in gout is very rare, and intradural gouty deposits have not been previously described. Intradural gout should be considered in the differential diagnosis of intradural masses.

Inflammatory aetiology of primary oesophageal achalasia: an immunohistochemical and ultrastructural study of Auerbach's plexus

AIM

Achalasia is a disease of the oesophagus characterized by increased lower oesophageal sphincter (LOS) tone, absence of LOS relaxation with swallowing and aperistalsis of the body of the oesophagus. The aetiology and pathogenesis of idiopathic achalasia is still controversial.

METHODS AND RESULTS

We examined 16 oesophageal biopsies and one low oesophagectomy specimen from patients with achalasia. The control group was composed of five autopsy cases with no history of oesophageal disorders, three cases of diffuse oesophageal spasm, one of gastro-oesophageal reflux disease and one patient with oesophageal carcinoma. Sections were immunostained for neurofilaments NF70 and NF200, S100 protein and neurone-specific enolase. Biopsies with inflammatory infiltrates, were in addition immunostained with antibodies against leucocyte common antigen as well as for CD20, CD43, CD68 and CD45RO. All biopsies were examined after plastic embedding, and electron microscopy (EM) was performed on samples containing autonomic plexus. An inflammatory infiltrate of varying intensity was present along the nerve fascicles and around ganglion cells in 90% of the cases of achalasia. T-lymphocytes predominated in all these cases. The autonomic nerves showed loss of fibres and degenerative changes which were discernible only by EM. Although there was no convincing neuronal loss or signs of active neuronal degeneration in biopsied cases, the oesophagectomy specimen revealed total absence of neurones and significant loss of nerve fibres. The control group showed normal plexuses and no inflammation.

CONCLUSION

Degeneration and significant loss of nerve fibres associated with predominant T-cell lymphocytic inflammatory infiltrate around the myenteric plexus support the concept for the inflammatory, probably autoimmune, aetiology of autonomic nervous system injury in primary achalasia.

Exercise intolerance due to mutations in the cytochrome b gene of mitochondrial DNA

BACKGROUND

The mitochondrial myopathies typically affect many organ systems and are associated with mutations in mitochondrial DNA (mtDNA) that are maternally inherited. However, there is also a sporadic form of mitochondrial myopathy in which exercise intolerance is the predominant symptom. We studied the biochemical and molecular characteristics of this sporadic myopathy.

METHODS

We sequenced the mtDNA cytochrome b gene in blood and muscle specimens from five patients with severe exercise intolerance, lactic acidosis in the resting state (in four patients), and biochemical evidence of complex III deficiency. We compared the clinical and molecular features of these patients with those previously described in four other patients with mutations in the cytochrome b gene.

RESULTS

We found a total of three different nonsense mutations (G15084A, G15168A, and G15723A), one missense mutation (G14846A), and a 24-bp deletion (from nucleotide 15498 to 15521) in the cytochrome b gene in the five patients. Each of these mutations impairs the enzymatic function of the cytochrome b protein. In these patients and those previously described, the clinical manifestations included progressive exercise intolerance, proximal limb weakness, and in some cases, attacks of myoglobinuria. There was no maternal inheritance and there were no mutations in tissues other than muscle. The absence of these findings suggests that the disorder is due to somatic mutations in myogenic stem cells after germ-layer differentiation. All the point mutations involved the substitution of adenine for guanine, but all were in different locations.

CONCLUSIONS

The sporadic form of mitochondrial myopathy is associated with somatic mutations in the cytochrome b gene of mtDNA. This myopathy is one cause of the common and often elusive syndrome of exercise intolerance.

Predicting the probability of meningioma recurrence based on the quantity of peritumoral brain edema on computerized tomography scanning

OBJECT

The goal of this study was to determine whether the quantity of peritumoral brain edema displayed on computerized tomography (CT) scanning could be correlated with brain invasion and subsequent recurrence of meningiomas.

METHODS

One hundred thirty-five patients who underwent resection of intracranial meningiomas at the Ottawa Civic Hospital were followed during the period 1980 to 1998. A complete resection was defined as one in which tumor, invaded bone, and involved dura were removed. Tumors were examined microscopically for evidence of brain invasion. The mean follow-up period was 9 +/- 4 years (standard deviation [SD]) and the mean time to recurrence was 5 +/- 4 years (SD). The authors used a simple grading system based on the average thickness (in centimeters) of edema seen on an axial CT slice showing the most tumor. Edema grade was linearly related to edema volume determined by digitizing the scans (r = 0.96; 29 cases). The chance of brain invasion increased by 20% for each centimeter of edema (r(s) = 1, p < 0.0001; 124 cases). The presence of brain invasion was predictive of recurrence after complete resection with an accuracy of 83%, a sensitivity of 89%, and a specificity of 82%. The chance of recurrence within 10 years after complete resection was given by the equation: percentage chance of recurrence = (centimeter of edema)3 x 0.7, which can be used to predict the chance of recurrence based on findings on CT scans (r(s) = 1, p < 0.0001; 86 patients). Statistical significance was confirmed using Kaplan-Meier and univariate and multivariate analyses. Completeness of resection was the most powerful predictor of recurrence (p < 0.00001, r = 0.6), followed by edema grade and brain invasion (both p = 0.02, r = 0.1). Patient age and gender and tumor location, size, and histological subtype were nonsignificant factors.

CONCLUSIONS

Brain invasion causes peritumoral edema. Invaded brain tissue is also the source of residual cells in cases of tumor recurrence after gross-total resection.

Angiogenic histogenesis of stromal cells in hemangioblastoma: ultrastructural and immunohistochemical study

Controversy regarding the origin of characteristic stromal cells (SC) is responsible for the placement of hemangioblastoma as a single entity in the category of "tumors of uncertain histogenesis" in the current WHO classification of brain tumors. This subclassification of hemangioblastoma is, to a large extent, a consequence of a remarkable antigenic heterogeneity of SC demonstrated in many, often contradictory immunohistochemical studies. In contrast, most of the electron microscopic studies demonstrated a number of features indicating angiogenic nature of SC and, therefore, hemangioblastoma. This study reevaluated the histogenesis of SC, applying immunohistochemistry as well as electron microscopy and immunoelectron microscopy. Immunohistochemical studies confirmed most of the previous results indicating a very frequent expression of vimentin, S-100 protein, neuron-specific enolase, and cytokeratins. SC were less commonly immunoreactive for desmin, factor XIIIa, and Ricinus communis lectin receptors, and only occasionally for factor VIII and Ulex europeus lectin. They were negative for other markers of endothelial, neuronal, glial, neuroendocrine, and smooth muscle differentiation. Approximately 1% of SC showed Ki67 immunoreactivity, indicating their slight proliferative activity, consistent with the benign nature of the tumor. In contrast to the inconclusive results of the immunohistochemistry, electron microscopy demonstrated a clear relationship of SC to endothelial cells, smooth muscle cells, and pericytes. Occasional SC were found within the vascular lumina. SC often showed intracellular caveolae consistent with the formation of early capillary lumina. Moreover, occasional SC contained small Weibel-Palade bodies positive for factor VIII in immunoelectron microscopy. SC represent a heterogeneous population of abnormally differentiating mesenchymal cells of angiogenic lineage, with some morphological features of endothelium, pericytes, and smooth muscle cells. Occurrence of SC in hemangioblastoma could be related to a limited ability of angioformative stromal cells to develop an architecture of capillary lumina integrated with the vascular network of the tumor. Hemangioblastoma should be reclassified and included together with other vascular tumors of the central nervous system.

Pleomorphic xanthoastrocytoma: what do we really know about it?

BACKGROUND

Pleomorphic xanthoastrocytomas (PXA) may recur and demonstrate aggressive clinical behavior with a mortality rate between 15% and 20%. To the authors' knowledge, no histopathologic features currently are known to reliably predict recurrence or tumor progression.

METHODS

The study was based on 71 cases with available information regarding clinical and therapeutic data and follow-up. Diagnostic features included cellular pleomorphism, giant and/or xanthic cells, eosinophilic granular bodies, desmoplasia, and leptomeningeal involvement. The mitotic index (MI), the presence of necrosis, and endothelial proliferation were recorded in all primary resection specimens.

RESULTS

The study included 35 females and 36 males, age 26+/-16 years (mean +/- standard deviation). Approximately 98% of tumors were supratentorial, with 49% in the temporal lobe. Seizures were the presenting symptoms in 71% of patients. Extent of tumor removal was macroscopic total resection in 68% of cases and subtotal resection (STR) in 32% of cases. Postoperative radiotherapy, alone or with chemotherapy, was administered in 29% and 12.5% of cases, respectively. The recurrence free survival rates (RFS) were 72% at 5 years and 61% at 10 years, whereas overall survivals rates (OS) were 81% at 5 years and 70% at 10 years. In univariate analysis, the extent of resection was the single factor associated most strongly with RFS (P=0.003), followed by MI (P=0.007) and atypical mitoses (P=0.04). Necrosis was not found to be significant. The extent of resection and MI were confirmed as independent predictors of RFS by multivariate analysis. MI (P=0.001), atypical mitoses (P=0.02), and necrosis (P=0.04) were associated with OS by univariate analysis. In multivariate analysis, only MI was an independent predictor of survival. Information regarding MIB-1 labeling index and the use of adjuvant therapy was too limited to explore their prognostic significance confidently.

CONCLUSIONS

The study confirms that PXA is an astrocytic tumor with a relatively favorable prognosis. MI and extent of resection appear to be the main predictors of RFS and OS. Given the slow growth of the tumor, more studied cases and longer periods of follow-up will be essential to confirm our findings regarding prognostic factors affecting this unusual tumor.

Neuronal loss and beta-amyloid removal in the amygdala of people with Down syndrome

The decrease in the number of neurons free of neurofibrillary changes, neurons with neurofibrillary degeneration, and the total volume of beta-amyloid (A beta) deposits in the amygdala of people with Down syndrome and in late stages of Alzheimer disease were estimated by using morphometry and regression analysis. This model predicts that the duration of neurofibrillary changes from the pretangle stage to ghost tangles is approximately 4.7 years. The correlation between the decrease in the number of neurons and the decrease in the amount of A beta indicates that amyloid deposition is associated with neurons and that loss of neurons causes decrease in A beta deposition. The presence of neurons only with neurofibrillary tangles, and the absence of the amyloid deposits predicted by regression analysis suggest that neurons with tangles are not engaged in amyloid deposition. The disappearance of amyloid by approximately 2.2 years after loss of neurons free of neurofibrillary changes indicates that A beta deposits are degradable and removable and that even in severely atrophic amygdala, there are mechanisms of amyloid resolution. This study shows that in normal aging in the amygdala, extracellular A beta appears later than neurofibrillary changes.

Myopathy with hexagonally cross-linked tubular arrays: a new autosomal dominant or sporadic congenital myopathy

We describe a slowly progressive myopathy with unique crystalloid inclusions in type 2 muscle fibers in a father and his son, as well as one more unrelated individual. The inclusions were strongly eosinophilic and purple by the Gomori method. They were composed of vesicular profiles, approximately 20 nm in cross-diameter, connected by radially arranged double spokes arising at 60 degrees angles. The inclusions were not related to any normal cellular organelle. Extensive immunohistochemical studies failed to reveal their chemical nature. It is suggested that this is a new congenital myopathy with characteristic intracytoplasmic inclusions, occurring sporadically or with an autosomal dominant pattern of inheritance.

Entorhinal cortex of aged subjects with Down's syndrome shows severe neuronal loss caused by neurofibrillary pathology

In Alzheimer's disease (AD), neurofibrillary degeneration of neurons starts in the transentorhinal cortex and spreads in a time-dependent manner to the entorhinal cortex, which provides a major input to the hippocampus--a key structure of the memory system. People with Down's syndrome (DS) develop neurofibrillary changes more than 30 years earlier than those with sporadic AD. To characterize AD-related pathology in the entorhinal cortex in DS, we examined seven subjects with DS of 60-74 years of age who died in the end stage of AD, and four age-matched control subjects. The volume of the entorhinal cortex in brains of subjects with DS was 42% less than that in control cases; however, the total number of neurons free of neurofibrillary changes was reduced in DS by 90%: from 9,619,000 +/- 914,000 (mean +/- standard deviation) to 932,000 +/- 504,000. The presence of 2,488,000 +/- 544,000 neurofibrillary tangles in the entorhinal cortex of people with DS, the prevalence of end-stage tangles, and the significant negative correlation between the total number of intact neurons and the percentage of neurons with neurofibrillary changes indicate that neurofibrillary degeneration is a major cause of neuronal loss in the entorhinal cortex of people with DS. The relatively low amyloid load (7 +/- 1%) and lack of correlation between the amyloid load and the volumetric or neuronal loss suggest that the contribution of beta-amyloid to neuronal loss in the entorhinal cortex is unsubstantial.

Vasculitic basilar artery thrombosis in chronic Candida albicans meningitis

BACKGROUND

Cerebrovascular complications of meningitis have been most extensively documented in the setting of acute bacterial or chronic tuberculous meningitis. Involvement of major cerebral vessels is rare and basilar artery thrombosis has not been reported in fungal meningitis secondary to candida infection.

METHODS

We describe the clinical course and neuropathological findings in a woman with chronic meningitis due to Candida albicans.

RESULTS

The diagnosis remained elusive antemortem despite analysis of 7 large volume CSF samples and examination of a meningeal and cortical biopsy. Death followed extensive brainstem and temporo-occipital infarction secondary to basilar artery thrombosis. The basilar artery occlusion was secondary to an intense, granulomatous and necrotizing basal meningitis focally extending to the media and intima.

CONCLUSIONS

This paroxysmal and devastating complication of untreated chronic candida meningitis reinforces that a trial of empirical therapy with both antituberculous and antifungal agents should be considered in most cases of chronic culture-negative lymphocytic meningitis.

Polymyositis in a patient with thymoma and T cell lymphocytosis

A patient presenting with agranulocytosis and lymphocytosis (4600/mm3) was found subsequently to have polymyositis (PM) and a thymoma. Immunophenotyping of the circulating lymphocytes revealed mature T cells (CD3, CD5, CD7 positive) with normal proportions of both CD4 (55%) and CD8 (38%) positive cells. PM was confirmed by electromyogram and muscle biopsy. Fewer than a dozen cases of thymoma and T cell lymphocytosis have been reported and ours is the first in which autoimmune manifestations have been noted. The presence of lymphocytosis in a patient with PM should prompt the search for a thymoma.

Immunohistochemical analysis of Bcl-2, Bcl-X, Mcl-1, and Bax in tumors of central and peripheral nervous system origin

The expression of Bcl-2, Bcl-X, Mcl-1, and Bax was examined by immunohistochemical methods in 93 tumors of nervous system origin, including 49 gliomas (30 astrocytomas and 19 glioblastoma multiforme (GMs)), 16 medulloblastomas (MBs), 19 neuroblastomas (NBs; 9 undifferentiated and 10 differentiated), and 9 miscellaneous neuroectodermal neoplasms. Among the 49 gliomas, immunopositivity (defined as > or = 10%) was observed for Bcl-2 in 45 (92%), Bcl-X in 48 (98%), Mcl-1 in 49 (100%), and Bax in 48 (98%) of 49 specimens. In 11 (37%) of 30 astrocytomas (WHO grades I to III), the tumor specimens were composed predominantly of malignant cells with strong-intensity Bcl-2 immunostaining, whereas none of the 19 GMs (WHO grade IV) exhibited strong-intensity Bcl-2 immunoreactivity (P = 0.001). Similarly, Mcl-1 immunointensity was strong in 15 (50%) of 30 astrocytomas, compared with only 2 (11%) of 19 GMs (P = 0.005). The percentage of Mcl-1-immunopositive tumor cells was also higher in astrocytomas than GMs (P < 0.002). Thus, contrary to a priori expectations, the expression of the anti-apoptotic proteins Bcl-2 and Mcl-1 was significantly higher in astrocytomas than in GMs. Of the 16 MBs, immunopositivity was found for Bcl-2 in 4 (25%), Bcl-X in 9 (56%), Mcl-1 in 8 (50%), and Bax in 16 (100%) of the cases. The intensity of immunostaining was strong for Bcl-2 in only 1 (6%) specimen, for Bcl-X in 3 (19%), and for Mcl-1 in 2 (12.5%), in contrast to Bax immunostaining, which was strong in 12 (75%) tumors. Significantly higher percentages of Bax-immunopositive tumor cells were also found in MBs, compared with Bcl-2, Bcl-X, and Mcl-1 (P < 0.0001). All 19 NBs were immunopositive for Bcl-2, Bcl-X, Mcl-1, and Bax. Higher percentages of Bcl-X- and Mcl-1-immunopositive tumor cells were observed in well differentiated tumors (P = 0.04 and 0.004, respectively). The intensity of Mcl-1 immunostaining was also generally higher in differentiated than undifferentiated NBs (strong immunointensity in 7 of 10 versus 0 of 9; P = 0.002). Conversely, strong-intensity Bax immunostaining was associated with undifferentiated histology (5 of 9 (56%) versus 1 of 10 (10%); P = 0.03). Taken together, these findings begin to delineate trends in the regulation of the relative levels of the Bcl-2 family proteins, Bcl-2, Bcl-X, Mcl-1, and Bax in gliomas, MBs, NBs, and some of their histological subtypes. The suggestion that expression of some of these Bcl-2 family genes may be differentially regulated in association with tumor progression and differentiation provides insights into the diverse biology and clinical behavior of these tumors of nervous system origin.

Association of pleomorphic xanthoastrocytoma with cortical dysplasia and neuronal tumors. A report of three cases

BACKGROUND

Several recent publications indicate that pleomorphic xanthoastrocytoma (PXA) may occasionally express ganglionic cell differentiation, linking this type of tumor to other benign, mixed glioneuronal neoplasms. Furthermore, ganglionic tumors and less frequently some benign glial tumors in the central nervous system, could be associated with a variety of mild developmental abnormalities of the cerebral cortex that are classified under the broad term cortical dysplasia. The association of cortical dysplasia with PXA and a neuronal pattern of differentiation has not been reported previously.

METHODS

The authors present clinical, radiologic, immunohistochemical, and ultrastructural findings in three patients with cortical dysplasia. The cortical dysplasia was continuous with PXA, displaying an additional component of neuronal cell differentiation.

RESULTS

The ages of the patients were 23, 47, and 52 years. Resection of the tumors was predated by temporal lobe seizures by 6 years in 1 patient and by more than 30 years in the others. In all 3 cases, radiologic studies conducted 3-6 years before surgery showed either no abnormality or lesions that were initially nonprogressing.

CONCLUSIONS

The longstanding clinical history of seizures and the existence of radiologically documented dormant lesions several years before tumor removal both suggest that PXA in these patients very likely developed in benign hamartomatous cortical lesions or in preexisting cortical dysplasia. The authors' findings, along with the consistent occurrence of PXA in the gray matter in the majority of the reported cases, indicate that these tumors may originate either from a subclass of astrocytes histogenetically and topographically associated with neurons or from multipotential neuroectodermal precursor cells common to neurons and astrocytes.

Adenovirus-mediated gene transfer of the tumor suppressor, p53, induces apoptosis in postmitotic neurons

Programmed cell death is an ongoing process in both the developing and the mature nervous system. The tumor suppressor gene, p53, can induce apoptosis in a number of different cell types. Recently, the enhanced expression of p53 has been observed during acute neurological disease. To determine whether p53 overexpression could influence neuronal survival, we used a recombinant adenovirus vector carrying wild type p53 to transduce postmitotic neurons. A control consisting of the same adenovirus vector background but carrying the lacZ reporter expression cassette was used to establish working parameters for the effective genetic manipulation of sympathetic neurons. We have found that recombinant adenovirus can be used at titers sufficiently high (10 to 50 multiplicity of infection) to transduce the majority of the neuronal population without perturbing survival, electrophysiological function, or cytoarchitecture. Moreover, we demonstrate that overexpression of wild type p53 is sufficient to induce programmed cell death in neurons. The observation that p53 is capable of inducing apoptosis in postmitotic neurons has major implications for the mechanisms of cell death in the traumatized mature nervous system.

Differentiating neuroblastoma of pituitary gland: neuroblastic transformation of epithelial adenoma cells. Case report

The authors report the case of a 40-year-old woman with a 12-year history of irregular menses, amenorrhea, infertility, galactorrhea, a slightly elevated prolactin level, and a slowly growing pituitary adenoma. She developed recent onset of visual symptoms, prompting craniotomy for removal of an intrasellar tumor. Following surgery, her vision and prolactin levels returned to normal. Light microscopic and immunohistochemical examination of the tumor revealed it to be a neuroblastoma, which was immunohistochemically positive for synaptophysin, S-100 protein, and oxytocin. The neoplasm contained prolactin-positive neuroblastic and pituitary epithelial cells. No other pituitary hormones were found. Electron microscopy demonstrated two cell types: one with frequent neuritic processes containing neurosecretory granules and showing synaptic specialization, and another one compatible with epithelial adenohypophyseal cells. A few cells had ultrastructural features that were transitional between neuronal cells and granulated epithelial cells. Agranular folliculostellate cells were also identified. Immunoelectron microscopy demonstrated prolactin granules in the cytoplasm of the epithelial cells, in a few transitional cells, and in scattered neuritic processes. Ultrastructural and immunohistochemical features of the tumor suggested a transformation of pituitary epithelium to neuroblastic cells. Hyperprolactinemia and associated clinical symptoms may in part be attributed to selective prolactin secretion by neoplastic cells that were differentiating into adenomatous pituitary cells and, to a lesser extent, to cells differentiating into a neuroblastic line. Compression of pituitary stalk might also have been a contributory factor to the increased prolactin levels. Moreover, the oxytocin produced by the neuroblastic cells was considered an additional stimulus for prolactin secretion by neoplastic cells or by the normal pituitary.

Degradation of nuclear matrix and DNA cleavage in apoptotic thymocytes

In dexamethasone-treated thymocyte cultures an increase in nuclear proteolytic activity paralleled chromatin fragmentation and the appearance of small apoptotic cells. The elevation of nuclear proteolytic activity was accompanied by site-specific degradation of nuclear mitotic apparatus protein and lamin B, two essential components of the nuclear matrix. Nuclear mitotic apparatus protein phosphorylation and cleavage into 200 and 48 kDa fragments occurred within 30 minutes of dexamethasone treatment. Cleavage of lamin B, which generated a fragment of 46 kDa consistent with the central rod domain of the protein, was also detected after 30 minutes of exposure to the steroid hormone. The level of lamin B phosphorylation did not change as a result of the dexamethasone treatment and the lamina did not solubilize until the later stages of apoptosis. Initial DNA breaks, detected by the terminal transferase-mediated dUTP-biotin nick end labeling assay, occurred throughout the nuclei and solubilization of lamina was not required for this process to commence. The data presented in this paper support a model of apoptotic nuclear destruction brought about by the site-specific proteolysis of key structural proteins. Both the nuclear mitotic apparatus protein and lamin B were specifically targeted by protease(s) at early stages of the cell death pathway, which possibly initiate the cascade of degradative events in apoptosis.

Cells differentiating into neuroectoderm undergo apoptosis in the absence of functional retinoblastoma family proteins

The retinoblastoma (RB) protein is present at low levels in early mouse embryos and in pluripotent P19 embryonal carcinoma cells; however, the levels of RB rise dramatically in neuroectoderm formed both in embryos and in differentiating cultures of P19 cells. To investigate the effect of inactivating RB and related proteins p107 and p130, we transfected P19 cells with genes encoding mutated versions of the adenovirus E1A protein that bind RB and related proteins. When these E1A-expressing P19 cells were induced to differentiate into neuroectoderm, there was a striking rise in the expression of c-fos and extensive cell death. The ultrastructural and biochemical characteristics of the dying cells were indicative of apoptosis. The dying cells were those committed to the neural lineages because neurons and astrocytes were lost from differentiating cultures. Cell death was dependent on the ability of the E1A protein to bind RB and related proteins. Our results suggest that proteins of the RB family are essential for the development of the neural lineages and that the absence of functional RB activity triggers apoptosis of differentiating neuroectodermal cells.

Primary intracranial pleomorphic angioleiomyoma--a new morphologic variant. An immunohistochemical and electron microscopic study

BACKGROUND

Angioleiomyomas usually are benign subcutaneous neoplasms that occur most often in extremities of middle-aged individuals. Very few cases have been described in other locations; none along the neuroaxis. An intracranial example of angioleiomyoma displaying unusual morphologic features not seen in the typical peripheral variants of this tumor is described.

METHODS

The tumor was studied with conventional histology, immunohistochemistry with morphometric calculation of proliferation index, immunoelectron microscopy, and DNA flow cytometry.

RESULTS

The tumor was composed of large epithelioid and pleomorphic cells filled with intermediate filaments positive for desmin and vimentin. Scattered cells also expressed myosin and muscle-specific actin. Smooth muscle cell differentiation was confirmed by ultrastructural demonstration of subplasmalemmal dense bodies, attachment plaques, and discontinuous basal lamina. The proliferation index with proliferating cell nuclear antigen (PCNA) monoclonal antibody was 75.78%, whereas it was only 4.22% with Ki67 monoclonal antibodies adopted to paraffin material (MIB-1).

CONCLUSION

The tumor represents a unique morphologic variant of a pleomorphic angioleiomyoma. Cellular pleomorphism and a strong reaction for PCNA in numerous cells suggested that the lesion was malignant. However, the absence of mitotic figures, a small number of Ki-67-positive cells, a diploic DNA pattern, and a low proliferation index in flow cytometry all supported the concept that this neoplasm represented an unusual histologic variant of benign angiogenic leiomyoma. Encapsulation and demarcation of the surgical specimen and the survival of the patient for more than 4 years without recurrence after resection support this interpretation.

Endonuclease activities associated with high molecular weight and internucleosomal DNA fragmentation in apoptosis

We have used pulsed-field gel electrophoresis and electron microscopy to correlate stages of DNA fragmentation with alterations of nuclear structure during apoptosis. DNA fragmentation occurs in two stages. The first is initiated by a previously undescribed endonucleolytic activity that cleaves DNA into 50- to 300-kb fragments. Electron microscopy showed that this degree of cleavage was sufficient to cause the chromatin to undergo condensation. The second stage of fragmentation is catalyzed by the previously described calcium-magnesium endonuclease. The enzyme activity responsible for the initial fragmentation of DNA was found to be distinct from that causing subsequent internucleosomal DNA cleavage based upon its cation requirements, independence of proteolysis and lack of inhibition by zinc. Both activities were found to preexist in nuclei from thymocytes, liver, HL60, and IL2-dependent CTLL cells. Thus, in apoptosis DNA degradation involves two distinct endonucleolytic activities, with only the first activity being essential for cell death.

Intracranial suprasellar angiolipoma: ultrastructural and immunohistochemical features

The authors present ultrastructural and immunohistochemical characteristics of an intracranial suprasellar tumor displaying features of cavernous angioma with islets of adipose tissue. Electron microscopy revealed thin-walled vessels separated by a loose collagenous stroma containing nests of mature adipocytes as well as fibroblasts, myofibroblasts, mast cells, and a few macrophages. Intracytoplasmic lipid droplets were also identified in scattered pericytes and smooth muscle cells of vascular walls and in the transitional cells resembling smooth muscle cells and adipocytes. Many adipose tissue cells were positive for S-100 protein with polyclonal antibodies. Other lipidized tumor cells were immunoreactive for some or all of the following: smooth muscle-specific actin, factor XIIIa, vimentin, and, occasionally, for desmin. Ultrastructure and immunohistochemistry indicate that in addition to typical adipocytes, lipidized cells of another nature contribute to the characteristic appearance of the adipose tissue component of angiolipoma.

Two-stage cell shrinkage and the OER for radiation-induced apoptosis of rat thymocytes

Suspensions of rat thymocytes were given 0.09-100 Gy using 60Co gamma-rays. The radiation-induced changes in the thymocytes were examined from minutes to hours post-irradiation using electron microscopy, agarose gel electrophoresis, staining and Coulter Counter sizing. Sizing by Coulter Counter showed, for the first time, that thymocytes which undergo apoptosis shrink in two distinct stages, first by a sudden decrease from an original volume of 99 microns 3 to a volume of 76 microns 3, followed by a gradual decrease to 57 microns 3 over the space of a few hours. The oxygen enhancement ratio for apoptosis was measured to be about 3.5, similar to the value for reproductive death for many mammalian cells.

Role of proteolysis in apoptosis: involvement of serine proteases in internucleosomal DNA fragmentation in immature thymocytes

Three chemically distinct serine, but not cysteine, protease inhibitors (phenylmethylsulphonyl fluoride, N-tosyl-L-phenylalanylchloromethyl ketone and 3,4-dichloroisocoumarin) prevented, in a dose-dependent manner, the characteristic apoptotic internucleosomal DNA cleavage (DNA ladder) typically observed in thymocytes in response to dexamethasone and teniposide VM-26. This effect was not the result of a direct inhibition of the Ca2+,Mg(2+)-dependent endonuclease, since oligonucleosomal DNA cleavage occurred in the presence of these inhibitors in isolated nuclei. The proteolytic step occurred at a very early stage of apoptosis, and preincubation of thymocytes with the inhibitors before dexamethasone or teniposide VM-26 were added irreversibly suppressed ladder formation. This implied that the cellular effector(s) of these compounds preexisted and were not resynthesized in response to the inducers of apoptosis. Serine protease inhibitors also suppressed apoptotic cell shrinkage and complete nuclear collapse, suggesting that these morphological changes were directly related to internucleosomal fragmentation of DNA. However, the serine protease inhibitors did not prevent high molecular weight DNA cleavage (> 50 kilobases) that preceded the ladder formation and thymocytes still died by apoptosis. This supported the view that internucleosomal DNA cleavage, considered to be the biochemical marker of apoptosis, might in fact be a late and dispensable step and that the newly described high molecular weight DNA cleavage might be a better indicator of apoptosis.

Variable distribution of mutant mitochondrial DNAs (tRNA(Leu[3243])) in tissues of symptomatic relatives with MELAS: the role of mitotic segregation

We studied multiple different postmortem tissue samples from a woman and two of her daughters with the MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) tRNA(Leu(UUR)) mutation at nucleotide 3243 in mitochondrial DNA (mtDNA). All tissues examined were heteroplasmic for the mutation. The mean proportion of mutant mtDNAs in the mother's tissues (0.30 +/- 0.10) was significantly lower than that of each of her daughters' (0.76 +/- 0.11, p < 0.03, and 0.72 +/- 0.13, p < 0.001); there was no difference in the fraction of mutant mtDNAs between the daughters (p < 0.71). This difference in the mean proportion of mtDNA mutants between family members correlates with their clinical profiles; the mother had the latest onset of disease and lived longest, while the two daughters had a strikingly similar clinical course. In individual patients, the mean proportion of mutant mtDNAs was not different in tissues deriving from ectodermal, mesodermal, and endodermal germ layers. Variance in the mutant:wild-type mtDNA ratio was normally distributed about the mean, both when all tissues were considered together and when different regions of the CNS were considered separately. Thus, the proportion of mtDNAs carrying the tRNA(Leu(3243)) mutation was not uniform in members of this pedigree and did not undergo rapid mitotic segregation along germ-layer divisions. These findings are consistent with the hypothesis that the overall proportion of mtDNAs carrying this mutation is primarily determined by segregation during oogenesis or early embryologic development and that random replicative (mitotic) segregation, subsequent to the establishment of primary germ layers, is responsible for the variation between tissues.

Immunoelectron microscopic localization of monoclonal IgM antibodies in gammopathy associated with peripheral demyelinative neuropathy

A sural nerve biopsy from a patient with benign monoclonal IgM kappa gammopathy and sensory-motor demyelinative neuropathy, revealed marked loss of myelinated fibers and focal axonal degeneration as well as widespread demyelination and remyelination with onion-skin formation. Almost all myelinated fibers displayed characteristic widening of the myelin lamellae as well as excessive thickness and/or exuberant outfoldings of myelin, reminiscent of that seen in tomaculous neuropathy. Many endoneurial capillaries were lined by fenestrated endothelium, indicating breakdown of a normal blood-nerve barrier. The endoneurium contained large amounts of extracellular proteinaceous material. Immunofluorescence and immunoelectron microscopy performed on the nerve of the patient, demonstrated selective deposition of IgM kappa gammaglobulin, exclusively in the areas of splittings of the myelin lamellae. Schwann cells contained cytoplasmic myelin debris labelled with IgM kappa only. In the indirect immunofluorescence and immunoelectron microscopy, serum of the patient reacted with the whole thickness of compact peripheral myelin of a normal human nerve. There was no immunoreactivity with the central myelin, Schwannoma cells, glial cells, axons or neurons. Demonstration of the selective presence of monoclonal IgM in widened lamellae of myelinated fibers, as well as bound to the internalized myelin debris in Schwann cells and macrophages, indicates a pathogenetic role of monoclonal paraprotein in myelin injury. Demyelination is promoted by development of endothelial fenestrations in the endoneurial capillaries and breakdown of the blood-nerve barrier.

Colloid cyst of the third ventricle. A comparative immunohistochemical study of neuraxis cysts and choroid plexus epithelium

In an effort to shed light upon the nature of the colloid cyst, the immunohistochemical properties of 21 examples of this lesion were compared with those of other neuraxial cysts and choroid plexus epithelium. The neuraxial cysts included the following: eight Rathke's cleft cysts, 25 pituitaries containing follicular cysts of the pars intermedia, and four enterogenous cysts. Fifteen examples of normal choroid plexus and 12 choroid plexus papillomas were studied as well. These lesions were examined for localization of the following antigens: cytokeratins, epithelial membrane antigen, secretory component, carcinoembryonic antigen, prealbumin, vimentin, glial fibrillary acidic protein (GFAP), S-100 protein, neuron-specific enolase, 68-kD neurofilament protein, chromogranin, serotonin, and lysozyme, and with Leu-7 monoclonal antibodies. Five colloid cysts were immunostained with monoclonal antibodies that were specific for Clara-cell antigens and surfactant, respectively. Sugar moieties were localized using Ulex europaeus I, and Ricinus communis agglutinin I lectins. All Rathke's cleft cysts and follicular cysts of the pars intermedia as well as three selected colloid cysts were examined for pituitary hormones. The epithelial cells of colloid and enterogenous cysts, as well as those lining follicular and Rathke's cleft cyst, showed uniformly strong reactivity for cytokeratins, epithelial membrane antigen, secretory component, and vimentin, and bound Ulex europaeus lectin. Occasional cells in colloid cysts were positive for Clara cell-specific antigens. Reaction for carcinoembryonic antigen was present on the apical surface of scattered cells of colloid, follicular, and Rathke's cleft cysts. Many cells of follicles in the pars intermedia as well as individual cells of five Rathke's cleft cysts were also immunoreactive for chromogranin, S-100 protein, GFAP, and pituitary hormones. Colloid and enterogenous cysts were negative for prealbumin, S-100 protein, GFAP, and neuron-specific enolase; in all but a few instances, they failed to bind Ricinus communis agglutinin. In contrast, normal choroid plexus and choroid plexus papillomas were positive for prealbumin, S-100 protein, neuron-specific enolase, cytokeratin, vimentin, and Ricinus communis agglutinin receptors; they lacked Ulex europaeus lectin, 56/66-kD cytokeratins, and epithelial membrane antigen. Unlike normal choroid plexus, choroid plexus papillomas were often GFAP-positive. All tissues studied were nonreactive for lysosome, serotonin, and neurofilament, and with Leu-7 antibodies. This study indicates that the immunophenotype of epithelium lining colloid cysts is similar to that of other cysts showing endodermal or ectodermal differentiation and to respiratory tract mucosa. Epithelium of colloid cysts is immunohistochemically different from that of normal or neoplastic choroid plexus. These findings indicate an endodermal rather than neuroepithelial nature for colloid cysts.

Retinoic acid- and staurosporine-induced bidirectional differentiation of human neuroblastoma cell lines

The differentiation pattern of two related human neuroblastoma cell lines, SK-N-SHF and SK-N-SHN, induced by retinoic acid and staurosporine was studied. Immunohistochemical and electron microscopic examination of the cells indicated that the SHF variant could undergo differentiation along a melanocytic route when treated with retinoic acid and to neuronal cells when treated with retionic acid and staurosporine together. Treatment of SHN cells with either or both these agents caused neuronal differentiation. The melanocytic pathway was characterized in part by the flattening of the cells, the appearance of melanocytic antigens and various forms of melanosomes, an increase in tyrosinase activity, and the absence of neuronal marker proteins. The neuronal route was typified by the development of long neuritic processes containing microtubules and numerous neurosecretory granules as well as by immunohistochemical reactions for neural cell adhesion molecule, synaptophysin, and neurofilament proteins. The significance of these results is discussed in terms of the differentiation responses of neuroblastoma cells to chemical agents as well as some of the factors involved in the regulation of phenotype expressions of these cells.

Suprasellar xanthomatous Rathke's cleft cyst

A case of a symptomatic suprasellar Rathke's cleft cyst in a 35-year-old woman is presented. The cyst wall and contents showed large collections of xanthomatous cells. With the exception of a few pituitary hormone-positive cells, immunohistochemical and ultrastructural features of the lining epithelium in this case of Rathke's cleft cyst were indistinguishable from colloid cysts of the third ventricle with similar secondary changes.

Ultrastructural studies of the cells forming amyloid in the cortical vessel wall in Alzheimer's disease

Ultrastructural studies of serial sections of the vessels with amyloid deposits in the brain cortex of patients with Alzheimer's disease showed that cells in the position of pericytes--perivascular cells--and perivascular microglial cells are producers of amyloid fibrils in the vascular wall. Three types of changes from normal are distinguishable in the vessel wall: (1) semicircular or circular thickening of vascular wall containing a large amount of amorphous material and various number of amyloid fibrils, (2) tuberous amyloid deposits containing both amorphous material and amyloid fibrils, some of the fibrils being arranged in strata and others arranged radially, and (3) amyloid star composed of a predominantly radial arrangement of bundles of amyloid fibrils and a less prominent amorphous component. A mixture of amorphous material and amyloid fibrils is present in cell membrane invaginations of perivascular cells, and occasionally perivascular microglial cells. Bundles of amyloid fibrils are found in altered cisternae of the endoplasmic reticulum and in the channels confluent with the infoldings of the plasma membrane of perivascular microglial cells. The amyloid deposition in the wall of the vessel causes degeneration of endothelial cells and the reduction of, and in some vessels obliteration of, the vessel lumen. In areas affected by amyloid angiopathy, extensive degeneration both of the neuropil and of neurons was observed. These changes were accompanied by astrogliosis. This study demonstrates similarities in amyloid formation in amyloid angiopathy and in beta-amyloid plaques in the neuropil and suggests that cells of the mononuclear phagocyte system of the brain (perivascular cells and perivascular microglia) are engaged in amyloid fibril formation.

Colloid cyst of the third ventricle: a comparative ultrastructural study of neuraxis cysts and choroid plexus epithelium

Thirteen colloid cysts (CC), four Rathke cleft cysts (RCC), three follicular cysts of normal pituitary gland (FCP), four enterogenous cysts (EC), three normal choroid plexi (CP), three choroid plexus papillomas (CPP), and several samples of normal bronchial mucosa and ependyma were studied by electron microscopy. The ultrastructure of most of the CC was indistinguishable from that of RCC, FCP, EC, and normal bronchial mucosa in demonstrating nonciliated and ciliated epithelial cells, goblet cells, basal cells, and intermediate forms, some showing evidence of early squamous differentiation. Two CC displayed mostly squamous differentiation, and one contained basally situated cells resembling myoepithelial cells. Although the RCC and FCP displayed features similar to those of CC, they also contained cells with electron-dense granules indicating pituitary hormone production and scattered cells showing oncocytic change. EC were lined by either squamous cells or mucin-producing columnar cells. Every CC, RCC, FCP, and EC contained cells covered by glycocalyx. In contrast to aforementioned lesions, ependymal lining, CP, and CPP were composed of a single cell type, one with numerous villi, few cilia, and no signs of keratinization, mucin production, or glycocalyx coating. It is concluded that the ultrastructural properties of CC are the same as those of cysts of endodermal or ectodermal origin and of respiratory mucosa. No ultrastructural similarities were observed between CC and normal or neoplastic neuroepithelium. These ultrastructural findings support the concept of an enterogenous origin of colloid cysts and highlight their similarity to RCC.

Melanotic cerebral ganglioglioma: evidence for melanogenesis in neoplastic astrocytes

A composite melanotic glial-ganglionic tumor was resected from a 17-year-old girl who presented with a 5-year history of epilepsy. Grossly, the tumor was partly cystic, partly solid, located superficially in the temporal lobe. Histologically, its glial component was composed of spindle and pleomorphic cells, including tumor giant cells, which were associated with Rosenthal fibers, eosinophilic granular bodies and marked desmoplasia. The cells had immunohistochemical and ultrastructural features of astrocytes, and some were invested by incomplete basal lamina. Thus, the tumor had many features in common with pleomorphic xanthoastrocytoma. However, its most striking feature was the presence of melanin pigment in numerous neoplastic cells. Immunoelectron microscopy revealed glial fibrillary acidic protein-positive intermediate filaments in tumor cells bearing melanosomes and premelanosome, proving their astrocytic nature. This case demonstrates, for the first time, melanosomal melanogenesis in human cells with astrocytic phenotype, and provides additional evidence for the ability of central neuroepithelial cell derivatives to produce melanin.

Caudate nucleus pathology in Parkinson's disease: ultrastructural and biochemical findings in biopsy material

Ultrastructural and biochemical properties of caudate nucleus (CN) biopsies in two patients with advanced Parkinson's disease (PD) were compared with three CN specimens removed during surgery for intracranial tumors. An additional two specimens from neurologically intact patients (59 and 86 years old) were removed during autopsy (performed 3 and 4 h post mortem, respectively) for electron microscopic studies. Dopamine levels in PD were reduced to less than 15% of control values. Both PD patients showed frequent dystrophic neurites and transsynaptic degeneration of neurons and neuritic processes. These changes were not found in CN from the four control individuals. Only a few dystrophic neurites were noticed in one 67-year-old control patient. The development of neuroaxonal dystrophy in CN is consistent with a dying-back process, probably accompanying abnormalities of axonal transport in PD. Transsynaptic degeneration of neurons in CN very likely represents a morphological marker of disease severity. The occurrence of this change may account for the poor clinical response of patients with advanced PD to intracerebral implantation of dopaminergic tissues.

Immunoelectron microscopy of Rosenthal fibers

Seventeen intracerebral gliomas containing Rosenthal fibers (RF) were studied by an immunoperoxidase method for localization of ubiquitin (UB), glial fibrillary acidic protein (GFAP), desmin and vimentin (VIM). The majority of RF showed an immunohistochemically negative core surrounded by a ring of overlapping reactions for UB, GFAP and VIM. Many RF were entirely negative for UB and intermediate filaments (IF). Immunoelectron microscopic localization of UB and GFAP was performed on seven selected tumors. UB was found in all RF and on IF in the proximity of RF. GFAP reaction was localized on astrocytic IF, including those trapped within RF, and within the granular component of some RF. In contrast to the light microscopic studies, neither GFAP- nor UB-negative RF were found on immunoelectron microscopy. VIM reaction on IF and a few RF was demonstrated in one tumor processed at low temperature into Lowicryl; it was much weaker than that for GFAP. Many cells with RF contained lysosome-like inclusions with material displaying electron density similar to adjacent RF; few of these inclusions were reactive for UB. It is concluded that RF formation is associated with ubiquitination of astrocytic IF. GFAP- and VIM-immunoreactive IF and products of their disintegration contribute to RF material. It is also suggested that the lysosomal system of astrocytes partially degrades RF.

Peripheral nerve and vasculature involvement in myophosphorylase deficiency (McArdle's disease)

A 60 year old white male presented with atypical chest pain and exercise-induced myalgia. Physical examination revealed slight proximal limb muscle weakness and wasting. Serum creatine phosphokinase levels were persistently elevated and electromyography showed changes consistent with a mild myopathy. Light microscopic and ultrastructural study revealed excess free glycogen within skeletal muscle, and histochemical staining showed absence of myophosphorylase activity. Biochemical quantitation confirmed the diagnosis of McArdle's disease by demonstrating absent phosphorylase activity in skeletal muscle with increased glycogen. In addition, increased amounts of free and membrane-bound glycogen were found within axons, Schwann cells, fibroblasts and occasional vascular smooth muscle and endothelial cells that had been included within the skeletal muscle biopsy. This case demonstrates more widespread glycogen accumulation than has been previously reported in McArdle's disease.

Vascular collagen fibril morphology in type IV Ehlers-Danlos syndrome

Morphometric analysis of transmission electron micrographs of blood vessel, skin and dura mater collagen fibers were performed on postmortem tissues taken from 28-year-old female with Ehlers-Danlos type IV syndrome (EDS IV). Vascular tissue from this patient was compared to 5 age- and sex-matched controls (age range 26-28 years). Our study revealed significant variation in collagen fibril diameter in the walls of almost all the vessels studied. In general, the EDS IV tissue showed a net decrease in average collagen fibril cross sectional area in arterial wall samples. This decrease was significant (p less than .05) across the entire wall of the renal artery, in the media of the carotid artery, and in the media and adventitia of the common iliac artery. Samples from the vena cava show significant increases in collagen fibril cross sectional area across the vessel wall (p less than .005). The only areas studied which did not show significant changes were the intimal and adventitial regions of the common carotid artery. The observed changes may be contributory to the decreased arterial wall strength typical of the syndrome.

Expression of retrovirally transduced IL-1 alpha in IL-6-dependent B cells: a murine model of aggressive multiple myeloma

Retroviral-mediated gene transfer was employed to introduce an IL-1 alpha cDNA into an IL-6-dependent murine B-cell line. Bone marrow metastases and bone lesions were frequently observed following intravenous injection of these B cells into syngeneic mice. Because the retroviral vector also contained the neomycin phosphotransferase gene, metastatic cells could be easily recovered from bone marrow by addition of G418 to the culture medium. Interestingly, the metastatic B cells were found to retain their IL-6 dependency through several transplant generations. By comparison, intravenous injection of autonomously-growing B-cell lines generated in vitro by retroviral introduction of an IL-6 cDNA rarely resulted in bone marrow metastases. These results demonstrate that abrogation of growth factor dependency is neither necessary nor sufficient for the in vivo growth and dissemination of tumor cells in this experimental system. It is proposed that the increased metastasis of the IL-1 alpha-producing B-cells to bone marrow is due to alterations in cell adhesion molecules. The B-cell bone marrow metastasis model described here may be useful for studies of bone marrow homing and for evaluation of therapeutic regimens for multiple myeloma.