Absent p53 immunohistochemical staining in a pituitary carcinoma.

BACKGROUND: Carcinomatous transformation of pituitary adenomas is uncommon, and is generally accompanied by nuclear accumulation of p53 protein. Pituitary carcinoma lacking accumulation of p53 protein is very rare, only two such cases being previously reported. METHODS: A patient presented with visual disturbance and cranial nerve palsies and was found to have a suprasellar mass. He underwent both transphenoidal and transfrontal excision of a nonfunctioning pituitary adenoma which recurred several times. The third recurrence was accompanied by multiple dural-based metastases. Despite aggressive surgical management, he continued to develop additional intracranial lesions and died two years after the discovery of metastatic disease. Specimens from 1984, 1995, 1997 and 1998 were available for histological and immunocytochemical analysis. Antibodies recognizing the pituitary hormones (ACTH, PRL, GH, FSH, LH and TSH), as well as cytokeratin, epithelial membrane antigen (EMA), glial fibrillary acidic protein (GFAP) and chromogranin A were applied to investigate the lineage of the neoplasm. Antisera specific for Ki-67 (MIB-1) and p53 protein were also applied to further delineate the biology of the tumour. RESULTS: Although cytokeratin and chromogranin A were detected in neoplastic cells. no expression of pituitary hormones was demonstrable, indicative of a nonfunctioning, null-cell pituitary adenoma. Nuclear pleomorphism and mitotic activity increased with subsequent resections. Abnormal accumulation of p53 protein was not observed, neither in early resections nor in the metastatic deposits. CONCLUSIONS: Failure to demonstrate p53 protein accumulation does not ensure a favourable outcome for pituitary adenoma. Accordingly, pituitary carcinoma may occur in the absence of p53 accumulation. The factors which underlie aggressive behaviour of pituitary neoplasms are uncertain but are under investigation.

November 2000: 13 year old girl with back pain and leg weakness.

A 13 year-old girl presented with back pain and recurrent falls of one year, with more recent loss of ambulation and bladder control. Examination showed spasticity and a sensory level bilaterally at T8. CT and MRI scans showed an epidural soft tissue mass with spinal cord compression and destruction of the pedicle, transverse process and other portions of a mid-thoracic vertebral body. Histologic examination of the gross total resection showed a pigmented villonodular synovitis (PVNS). PVNS is most common in the knee and only 26 cases have been reported in the spine. Although vertebral bodies are rarely involved, it is important to include PVNS in the differential diagnosis of spinal lesions because of its tendency to recur locally if not totally resected.

Spinal angiolipoma.

BACKGROUND: Spinal epidural angiolipoma is a rare cause of spinal cord compression. We present a case and review the clinical presentation, radiological appearance, pathological aspects and treatment of this distinct clinico-pathological entity. METHODS: A case of a 46-year-old woman with a five-month history of progressive myelopathy affecting her lower extremities is presented. CT and MRI revealed a large epidural fat-containing mass compressing the spinal cord dorsally at the T7-T8 level. A laminectomy was performed with gross total resection of the lesion. RESULTS: The patient's neurologic symptoms improved postoperatively. A two-year follow-up period has revealed no signs of tumor recurrence and no neurological deficit. CONCLUSION: The diagnosis of spinal angiolipoma should be considered in the differential diagnosis of spinal cord compression. Magnetic resonance imaging is the investigation of choice. The surgical objective is complete excision but, for anterior lesions involving bone, an overly aggressive approach should be tempered by an awareness of the overall indolent natural history of so-called "infiltrating" spinal angiolipomas that are only partially excised.

Mevalonate prevents lovastatin-induced apoptosis in medulloblastoma cell lines.

BACKGROUND: 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) is a key rate-limiting enzyme in the mevalonate pathway, which generates precursors for cholesterol biosynthesis and the production of non-steroidal mevalonate derivatives that are involved in a number of growth-regulatory processes. We have reported that lovastatin, a competitive inhibitor of HMG-CoA reductase, not only inhibits medulloblastoma proliferation in vitro, but also induces near-complete cell death via apoptosis. The present study explores some of the pathways which may be involved in lovastatin-induced apoptosis. METHODS: Medulloblastoma cell lines were exposed in vitro to lovastatin with or without mevalonate, and document the effects using morphology, flow cytometry. DNA electrophoresis and Northern analysis. RESULTS: 1) Mevalonate prevents apoptosis when co-incubated with lovastatin, or when administered to lovastatin-pretreated cells. 2) Mevalonate restores the lovastatin-arrested cell cycle, allowing S phase entry. 3) Mevalonate does not prevent lovastatin-induced apoptosis after a critical duration of lovastatin pretreatment. For cell lines Daoy and UW228 this was 24 hours, and for D283 Med and D341 Med it was 48 hours. 4) Increases in HMG-CoA reductase mRNA levels induced by lovastatin are abrogated by co-incubation with lovastatin and mevalonate. CONCLUSIONS: These results confirm that lovastatin inhibition of this enzyme results in blockage of the mevalonate pathway, and that such a block is a critical step in the mechanism of lovastatin-induced apoptosis.

Apoptosis of medulloblastoma cells in vitro follows inhibition of farnesylation using manumycin A.

Medulloblastoma is a malignant cerebellar tumor usually manifesting in childhood. We have previously shown that blocking the mevalonate pathway with lovastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, inhibits medulloblastoma proliferation and induces apoptosis in vitro. The underlying mechanism may involve blocking post-translational modification of important mitogenic signal-transduction proteins. We show that p21 ras processing is blocked by lovastatin, suggesting that inhibition of isoprenylation may be important in lovastatin-induced apoptosis. To test this hypothesis, manumycin A, an antibiotic which inhibits farnesyl protein transferase and thus farnesylation, was administered to 4 medulloblastoma cell lines in vitro. We found that blocking protein farnesylation with manumycin A was followed by apoptosis in a time- and dose-dependent manner. However, cell death induced by manumycin A was uniformly more rapid and efficient, requiring only 12 to 24 hr of treatment, than lovastatin-induced apoptosis, which required 36 to 96 hr (depending on the cell line tested). In addition, unlike lovastatin, which caused cell-cycle arrest in G1 phase and HMG-CoA reductase gene up-regulation, manumycin A had no effect on the cell cycle and resulted in down-regulation of HMG-CoA reductase gene expression. In both lovastatin- and manumycin A-treated cells, cellular cysteine protease precursor (CPP32) was activated, confirming the occurrence of apoptosis.

Lovastatin-induced apoptosis of human medulloblastoma cell lines in vitro.

Medulloblastoma is a malignant paediatric central nervous system tumor with a poor prognosis, stimulating the evaluation of improved treatment strategies. Lovastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, is currently used to treat patients with hypercholesterolemia. This compound also inhibits the production of non-steroidal mevalonate derivatives that are implicated in the control of cellular proliferation, and can induce cell-cycle arrest in vitro. We recently showed that lovastatin inhibited growth and promoted apoptosis of neuroblastoma, the peripheral nervous system 'cousin' of medulloblastoma. Therefore the potential of lovastatin as a possible anticancer drug against medulloblastoma was evaluated in vitro. Four medulloblastoma cell lines, Daoy, UW228, D341 Med and D283 Med, were treated with 1-40 microM of lovastatin in vitro. Analysis of cell morphologic changes, cell viability, DNA fragmentation and flow cytometry in all four cell lines showed growth inhibition and induction of apoptosis with lovastatin treatment. As little as 10 microM of lovastatin was sufficient to cause a marked reduction in cell numbers, and more than 20 microM of lovastatin induced >90% cells to undergo apoptosis, after intervals ranging between 36 and 96 h, depending on the cell line. Lovastatin induced apoptosis in these cell lines was concomitant with cell cycle arrest in G1. The attached cell lines UW228 and Daoy were more sensitive to lovastatin than D283 Med and D341 Med. Daoy cells which survived several cycles of lovastatin treatment could still be induced to undergo apoptosis after longer treatment times. The efficient induction of apoptosis by lovastatin favours this drug as a potential new avenue of therapeutic intervention for medulloablastoma.

Immunohistochemical localization of calmodulin-dependent cyclic phosphodiesterase in the human brain.

The amplification of cyclic nucleotide 'second messenger' signals within neurons is controlled by phosphodiesterases which are responsible for their degradation. Calmodulin-dependent phosphodiesterase (CaMPDE) is an abundant enzyme in brain which carries out this function. For the first time, we have localized CaMPDE in the normal human brain at various ages, using a mononoclonal antibody designated A6. This antibody was generated using standard techniques, purified, and applied to tissue sections. Autopsy specimens of human brain with no neuropathological abnormalities were selected representing a range of pre- and postnatal ages. Sections of various brain regions were evaluated for immunoreactivity, graded as nil, equivocal, or definite. We demonstrated definite CaMPDE immunohistochemical staining in neocortex, especially in neurons in layers 2 and 5. There was definite neuronal immunoreactivity in the hippocampus, and in the subiculum. The striatum had definite patchy neuronal staining. Definite terminal staining in the globus pallidus externa and substantia nigra pars reticulata outlined resident neurons, interpreted as axonal terminal staining. Cerebellar Purkinje cells showed definite immunoreactivity. In the developing brain, definite immunohistochemical staining was seen in the cerebellar external granular layer. The expression of CaMPDE in specific subsets of neurons suggests they may correlate with cells having dopaminergic innervation and/or high levels of neuronal integration.

Pathologic findings of multiple sulfatase deficiency reflect the pattern of enzyme deficiencies.

Multiple sulfatase deficiency is a rare metabolic storage disorder that manifests in childhood. It is probably an autosomal-recessive inherited condition, the gene for which has not yet been identified. Clinical features include mental deficiency and a dysmorphic appearance reminiscent of a mucopolysaccharidosis. Unlike most storage disorders, there are multiple deficient enzymes; all are sulfatases, hence the name of the disorder. Biochemical testing reveals accumulation of glycosaminoglycans, sulfatides, and gangliosides in the brain and other tissues of affected patients. In previous accounts of postmortem examinations, white matter histologic and biochemical pathologic findings similar to metachromatic leukodystrophy have been reported. Ganglioside accumulation, secondary to interference with degradative enzyme activity by the accumulating glycosaminoglycans also has been demonstrated. The authors report a case of multiple sulfatase deficiency with only mild deficiencies of the arylsulfatases but with severe deficiencies of iduronate sulfatase and heparan sulfamidase. Pathologic changes were more in keeping with a mucopolysaccharidosis, with minimal white matter changes and deposition of metachromatic material. The authors postulate that the mild leukodystrophic changes but striking features similar to a mucopolysaccharidosis are reflections of the pattern of enzyme deficiency. The pathology of multiple sulfatase deficiency therefore represents an overlap between a leukodystrophy and a mucopolysaccharidosis, with the relative contribution of each pattern apparently depending on the pattern of enzyme deficiency encountered in each patient.

Ruptured Rathke's cleft cyst: a possible cause of Tolosa-Hunt syndrome.

Unexpected autopsy findings are presented of a patient who died suddenly after a 6-month history of progressive headaches, nausea, and vomiting. A ruptured Rathke's cleft cyst (RCC) was identified within the adenohypophysis, with a chronic inflammatory reaction in surrounding pituitary and overlying hypothalamus. A brisk lymphoplasmacytic response was also seen in the cavernous sinuses bilaterally, identical to the pathology reported for idiopathic painful ophthalmoplegia, also called Tolosa-Hunt syndrome (THS). The pathogenesis of THS has not been elucidated; based on the findings in this report, it is suggested that some THS cases may result from a hyperimmune response to RCC rupture with extension into one or both cavernous sinuses. Although prompt alleviation of symptoms with corticosteroid treatment is generally encountered with THS, recurrence of symptoms is not uncommon. A careful search for a ruptured RCC should be undertaken in atypical cases of THS, with possible consideration of surgical intervention.

Histological and ultrastructural analysis of six colloid cysts in children.

Although colloid cysts of the third ventricle are unusual in children, we have recently encountered six examples. Histologically they were lined by cuboidal, pseudostratified or columnar ciliated and mucous-secreting epithelial cells. Two cases showed small microcysts within the fibrovascular stroma surrounding the main cyst. The outermost layer consisted of a glial-ependymal envelope, in keeping with the postulated supraventricular origin of colloid cysts. Scanning electron microscopy showed 10-40% ciliated cells, and no ballooning of non-ciliated cells. Aspiration of cyst contents was performed in three patients, two of whom subsequently required surgical resection 4 months and 8 years after drainage, respectively. In adults colloid cysts may be asymptomatic, whereas in children they have not been documented as incidental findings at autopsy. Two of our six cases died, both before a diagnosis was established. A colloid cyst of the third ventricle must be included in the evaluation of acute neurological deterioration in children, in whom they are more frequently lethal.

Calmodulin-dependent cyclic nucleotide phosphodiesterase in human cerebral cortex and glioblastoma multiforme.

BACKGROUND: Calmodulin-dependent cyclic nucleotide phosphodiesterase (CaMPDE) has been extensively studied and characterized in normal mammalian tissues; however very little is known about this enzyme in human brain tumors. It has been established that high levels of this enzyme exist in non-central nervous system tumors, PDE inhibitors or cAMP analogues have been used to treat them. This study has examined the levels of CaMPDE in glioblastoma multiforme from six patients and has compared these to the levels of CaMPDE in four patients with normal cerebral tissue. In addition, an enzyme immune assay method (EIA) was developed in this study for the detection of CaMPDE in human cerebral tissue. This method is proposed to be used as an adjunct to the spectrophotometric method presently utilized. This would be beneficial in cases where small tissue samples, for example in stereotactic biopsy, are available. METHODS: The CaMPDE activity and corresponding levels of expression in cerebral tissue from temporal lobectomies and both surgical extraction or stereotactic biopsy in patients with primary tumors were determined by spectrophotometric and EIA, respectively. The EIA was developed from the production of a polyclonal antibody against bovine brain 60 kDa CaMPDE isozyme. Cross reactivity of the antibody with human was confirmed using transblot and immunohistochemistry. RESULTS: Utilising the EIA, there was found to be significant reduction in both catalytic activity (p < 0.001) and in quantitative protein expression (p < 0.001) in glioblastoma multiforme from patients when compared to normal cerebral cortex. Immunoblotting experiments and immunohistochemistry demonstrated that CaMPDE in glioblastoma multiforme failed to react with a polyclonal antibody raised against bovine brain 60 kDa CaMPDE isozyme, whereas the enzyme from normal tissue reacted with antibody. CONCLUSIONS: Contrary to other studies on non-CNS tumors, the catalytic activity and the protein expression of CaMPDE is reduced in glioblastoma multiforme. The EIA method is a more sensitive in detecting CaMPDE than in the spectrophotometric method, especially when a small amount of tissue is available. Immunohistochemistry and the EIA may be useful in the future to use as markers for other types of brain tumors and not for glioblastoma multiforme as demonstrated.

Increased mitotic activity as a negative prognostic indicator in pleomorphic xanthoastrocytoma. Case report.

Pleomorphic xanthoastrocytoma is a recently characterized neoplasm with a favorable prognosis despite aggressive histological features. The authors report a case of pleomorphic xanthoastrocytoma that recurred 4 years after complete gross resection. The original tumor exhibited histological features characteristic of this neoplasm, but up to 4 mitoses/10 high-power fields were present focally. The recurrent tumor contained small foci of classical pleomorphic xanthoastrocytoma, but consisted predominantly of glioblastoma multiforme. Transitional zones contained nests of glial fibrillary acidic protein (GFAP)-immunopositive cells surrounded by delicate collagenous and reticulin-rich septa. Electron microscopy of the transitional zone showed continuous basal lamina investing cells containing bundles of intermediate filaments. These were GFAP-positive by immunogold electron microscopy, confirming the astrocytic nature of pleomorphic xanthoastrocytoma. This example illustrates the capacity of this tumor to evolve into glioblastoma. The indolent clinical behavior of most pleomorphic xanthoastrocytomas is evident from a literature review, which confirms the prolonged survival of many patients after onset of symptoms. Completeness of excision, subjectively assessed at surgery, did not influence the risk of recurrence or survival up to 10 years after initial resection. Postoperative radiotherapy did not improve survival, but may reduce the probability of recurrence; more studies are needed to corroborate this finding. The data compiled herein support the designation of pleomorphic xanthoastrocytoma as a distinct astrocytic neoplasm with a favorable prognosis. An increased mitotic rate has not previously been correlated with a worse outcome, and should not be used to exclude this diagnosis. However, anaplastic transformation of pleomorphic xanthoastrocytoma confers a much worse prognosis, and this case suggests that increased mitotic activity may be a negative prognostic indicator since it may herald subsequent anaplastic transformation.

Assessment of autonomic function in humans by heart rate spectral analysis.

Spectral analysis of spontaneous heart rate fluctuations were assessed by use of autonomic blocking agents and changes in posture. Low-frequency fluctuations (below 0.12 Hz) in the supine position are mediated entirely by the parasympathetic nervous system. On standing, the low-frequency fluctuations increase and are jointly mediated by the sympathetic and parasympathetic nervous systems. High-frequency fluctuations, at the respiratory frequency, are decreased by standing and are mediated solely by the parasympathetic system. Heart rate spectral analysis is a powerful noninvasive tool for quantifying autonomic nervous system activity.