PubMed Health⌕ Search

Biomedical subjects

Richard A Prayson

Publications and source records attributed to Richard A Prayson.

At least 55 records · Page 3Linked to original sources
PubMed2004

9p21 and 13q14 dosages in ependymomas. A clinicopathologic study of 101 cases.

Ependymomas are glial neoplasms whose clinical behavior is difficult to predict based on histology alone. Recently, a comparative genomic hybridization study identified frequent chromosome 9p and 13q losses in anaplastic ependymomas, suggesting that p16 and RB alterations may be involved in tumor progression. In order to test this hypothesis further, 101 myxopapillary, conventional, and anaplastic ependymomas (51 spinal and 50 intracranial tumors) were tested for RB and p16 deletions using fluorescence in situ hybridization. Clinical follow-up, ranging from 2 to 198 months (median 46 months), was obtained in 90 cases (91%). RB and p16 deletions were seen in 22 of 92 (24%) and 22 of 89 (25%) informative cases, respectively. Polysomies were more frequent in the grade I and II spinal tumors, consistent with prior reports of increased aneuploidy in such cases. No significant genetic associations were seen with tumor grade, recurrence, or death, suggesting that 9p and 13q deletions do not play a prominent role in the malignant progression of ependymomas, as has been implicated in other glioma subtypes.

Adolescent↗
PubMed2004

Cerebellar paraganglioma.

Paragangliomas arising as primary neoplasms in the intracranial portion of the central nervous system are relatively uncommon and only have been rarely reported. We report a case of apparent primary paraganglioma arising in the left cerebellar hemisphere in an 11-year-old girl who presented with a 6-month history of headaches. The tumor was marked by a nested architectural pattern (zellballen), delimited by S-100-positive sustentacular cells. Morphologic and immunohistochemical features of the neoplasm are discussed and literature is reviewed regarding involvement of the central nervous system by paraganglioma.

Cerebellar Neoplasms↗
PubMed2004

Detection of polyoma virus in brain tissue of patients with progressive multifocal leukoencephalopathy by real-time PCR and pyrosequencing.

We evaluated 2 methods, a LightCycler PCR assay and pyrosequencing for the detection of the JC polyoma virus (JCV) in fixed brain tissue of 10 patients with and 3 control patients without progressive multifocal leukoencephalopathy (PML). Nucleic acid extraction was performed after deparaffinization and proteinase K digestion. The LightCycler assay differentiates the BK virus (BKV), JCV, and SV40 using melt curve analysis. Conventional PCR was used with the same primers to generate products for pyrosequencing. Two sequencing primers were used that differentiate the polyoma viruses. Seven of 11 biopsies (1 patient had 2 biopsies) with PML were positive for JCV by real-time PCR and/or PCR/pyrosequencing. Three of 4 remaining biopsies were positive by real-time PCR but had melting points between JCV and SV40. The 4 specimens that were negative or atypical by LightCycler PCR were positive by traditional PCR, but 1 had an amplicon of lower molecular weight by gel electrophoresis. These were shown to represent JCV by at least 1 of the 2 pyrosequencing primers. The biopsies from patients without PML were PCR negative. Both the LightCycler and pyrosequencing assays are useful for confirming JCV in brain biopsies from patients with PML, but variant JCVs may require supplementary methods to confirm JCV infection.

BK Virus↗
PubMed2004

Gene expression profiling reveals unique molecular subtypes of Neurofibromatosis Type I-associated and sporadic malignant peripheral nerve sheath tumors.

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive Schwann cell neoplasms that are frequently associated with Type I Neurofibromatosis (NF1) and respond poorly to current therapeutic regimens. To better understand the molecular heterogeneity of these tumors, we performed gene expression profiling on 25 NF1-associated and 17 sporadic MPNSTs using oligonucleotide microarrays representing approximately 8100 unique human gene transcripts. Using several previously reported statistical approaches, we were unable to identify a molecular signature that could reliably distinguish between NF1-associated and sporadic MPNSTs in independent training and test sample sets. However, using an unsupervised clustering approach, we identified an extensive gene expression signature that distinguished 9 of the 42 tumors analyzed. This signature corresponded to relative overexpression of transcripts associated with neuroglial differentiation (NCAM, MBP, L1CAM, P1P) and relative down-regulation of proliferation and growth factor associated transcripts (IGF2, FGFR1, MDK, Ki67). All tumors with this gene expression signature lacked expression of EGFR and all but one tumor were derived from patients with NF1. However, there were no other obvious associations with histological grade, tumor site, metastasis, recurrence, age, or patient survival. We conclude that distinct molecular classes of MPNST exist and that the ability to stratify these tumors based on unique and biologically relevant gene expression profiles may be important for future targeted therapeutics.

Adolescent↗
PubMed2003

Cyclooxygenase-2 in oligodendroglial neoplasms.

BACKGROUND: Although increased expression of cyclooxygenase-2 (COX-2) has been described in association with a variety of neoplasms, including tumors of astrocytic derivation, limited data are available on COX-2 expression in oligodendrogliomas. METHODS: The current study retrospectively reviewed 53 oligodendrogliomas and 7 oligodendroglioma-predominant oligoastrocytomas (mixed gliomas) for COX-2 expression and MIB-1 proliferative index (by immunohistochemistry) and for chromosome 1p status (by fluorescence in situ hybridization). RESULTS: Patients included 35 males and 25 females, with a mean age of 41 years (range, 12-73 years) at the time of surgery. Forty-four tumor specimens were classified as World Health Organization (WHO) Grade II neoplasms and 16 as WHO Grade III tumors. MIB-1 labeling indices (marker of cell proliferation) ranged from 0 to 22.3 (mean 4.5). Twenty-eight tumor specimens demonstrated allelic loss on chromosome 1p. Positive staining was observed in 17 tumor specimens with COX-2 antibody. COX-2-positive tumor specimens were also evaluated with CD68 (macrophage/microglial cell marker) by coimmunolabeling to confirm that the observed COX-2 immunostaining was not due to immunoreactive macrophages or microglial cells. COX-2 expression, lack of allelic loss at chromosome 1p, and high proliferation indices were associated with decreased survival (P = 0.002, P = 0.009, and P = 0.015, respectively). No correlation with outcome was found with patient gender, age at diagnosis, or histologic grade. CONCLUSIONS: Chromosome 1p, COX-2 immunoreactivity, and MIB-1 labeling indices correlated with outcome and were associated with decreased survival. There was not a one-to-one correspondence between COX-2 immunoreactivity and lack of allelic loss at chromosome 1p. Tumors with expression of COX-2 by immunohistochemistry may, in theory, benefit from treatment with therapeutic agents that inhibit COX-2.

Adolescent↗
PubMed2003

Clinicopathologic study of 43 patients with sural nerve vasculitis.

Vasculitis is a relatively uncommon finding in sural nerve biopsy specimens and is associated with significant morbidity. This study retrospectively reviewed the clinicopathologic features of 43 patients (44 sural nerve biopsy specimens) with sural nerve vasculitis, defined as infiltration of vessel walls by inflammatory cells. These biopsy specimens were obtained over a 19-year period, during which 1503 nerve specimens were reviewed. The study group comprised 29 females and 14 males, ranging in age from 19 to 94 years (mean, 72.5 years) at the time of biopsy. The most frequent clinical presentations included paresthesias in 19 patients (61%), pain in 17 patients (57%), weakness in 10 patients (32%), and weight loss in 9 patients (29%). Histologically, 26 of 44 biopsy specimens (59%) demonstrated necrotizing vasculitis. The remaining 18 biopsy specimens demonstrated a nonnecrotizing lymphocytic vasculitis. Eosinophils were identified in 4 biopsy specimens, intravascular thrombi in 10 (22%) specimens, and granulomatous inflammation in 1 specimen. In 39 biopsy specimens (89%), multiple vessels were involved by vasculitis. Epineurial vessels were the most common target of vasculitis, (n = 42; 95%). Evidence of vascular wall scarring, indicative of healed vasculitis, was observed in 13 biopsy specimens (30%). All biopsy specimens showed evidence of axonopathy, with mild axonal loss noted in 14 specimens (32%), moderate loss in 18 specimens (41%), and severe loss in 12 specimens (27%). Concomitant muscle biopsy was performed in 31 patients. Fifteen muscle biopsy specimens demonstrated evidence of vasculitis (48%), which was necrotizing in 11 cases. All muscle biopsy specimens demonstrated features of neurogenic atrophy. Twenty-five out of 32 patients were known to have been treated with steroids and demonstrated some degree of clinical improvement. In conclusion, sural nerve vasculitis is a relatively uncommon pathological finding (prevalence of 2.9% in this study). In most cases, multiple vessels were involved. Concomitant vasculitis was also identified in about half of the muscle biopsy specimens obtained at the time of nerve biopsy. In most patients, the vasculitis appeared to be at least partially responsive to immunosuppressive therapy.

Adult↗
PubMed2003

Cortical dysplasia in extratemporal lobe intractable epilepsy: a study of 52 cases.

Cortical dysplasias or malformations due to abnormalities of cortical development are a well-recognized cause of intractable seizures. This study retrospectively examines the clinicopathologic features of 52 cases of extratemporal cortical dysplasia (from 135 total resections performed over a 16-year period). The study consists of 52 patients (27 males; 25 females) who underwent extratemporal resection for epilepsy at a mean age of 15.1 years (range, 3 months to 44.1 years). Seizure duration before surgery ranged from 7 to 372 months (mean duration, 129 months). Patterns of cortical dysplasia observed included diffuse architectural disorganization (n=48), neuronal cytomegaly (n=32), increased number of molecular layer neurons (n=32), balloon cells (n=19), gray matter heterotopia (n=3), neuronal glial clustering (n=3), and pial glial neuronal tissue (n=2). Five patients had coexistent nodular hamartomas. Coexistent tumors were present in five patients; including three dysembryoplastic neuroepithelial tumors, one ganglioglioma, and one low-grade fibrillary astrocytoma. Two patients had tuberous sclerosis. Follow-up was available in 50 patients (mean follow-up, 29 months). Thirty-eight patients (73%) had complete resolution or significant decrease in seizure frequency, 13 patients (25%) had increased seizures or no change in seizures, and one patient died in the postoperative period. In conclusion, (1). cortical dysplasia was identified in 38.5% of extratemporal resections for epilepsy; (2). the common cortical dysplasia patterns observed included diffuse cortical disorganization, neuronal cytomegaly, and increased molecular layer neurons; (3). 10% of extratemporal cortical dysplasia was associated with tumors; (4). improved seizure control was obtained in approximately three fourths of patients after resection; and (5). seizures associated with balloon cell dysplasia were less successfully managed with surgery.

Adolescent↗
PubMed2003

Seizure outcome after temporal lobectomy in temporal lobe cortical dysplasia.

PURPOSE: To identify the temporal lobe cortical dysplasia (CD) histopathology classification subtype and determine the seizure outcome of patients who underwent temporal lobectomy with coincident CD. METHODS: We reviewed the data of 28 patients with temporal lobe epilepsy who underwent surgery with pathologically verified CD at our institution from 1990 to 2000. The seizure outcome was assessed at a minimum of 1 year after surgery according to Engel's classification. RESULTS: Of 28 patients who underwent surgery, nine (32.1%) had isolated CD, and 19 (67.9%) had CD and hippocampal sclerosis (CD&HS). Twenty-six (92.9%) patients had histopathology subtype Ia (architectural abnormalities). Twenty (71.4%) patients were seizure free (Engel class I). Favorable seizure outcome (Engel class I, II) was achieved in 26 (92.9%) patients. No difference in seizure outcome was noted between patients with CD and CD&HS. CONCLUSIONS: The most common histopathologic subtype in patients with temporal lobe CD is type Ia (architectural abnormalities). Temporal lobectomy in temporal lobe epilepsy patients with CD can achieve favorable seizure outcome.

Adolescent↗
PubMed2003

Interobserver variability in determining MIB-1 labeling indices in oligodendrogliomas.

Several studies have shown that MIB-1 labeling indices correlate well with tumor grade and prognosis in a variety of tumor types. Several factors are responsible for some degree of variability in the determination of labeling indices. Interobserver variability is one of the factors often cited as responsible for this variability. A slide from each of 30 oligodendrogliomas, stained with MIB-1 antibody, was distributed to six pathologists. The same set of slides was reviewed by each individual. Each pathologist was instructed to determine a MIB-1 labeling index by evaluating 1,000 tumor cell nuclei from the area of the slide with the most staining. The labeling index record reflected a percentage of positive-staining tumor cells. Interobserver agreement was compared. MIB-1 labeling indices ranged from 0 to 45.7. Overall agreement was good (> or =0.75) with a concordance coefficient of 0.832 (confidence interval, 0.700 to 0.909). Variability was greater among tumors with higher labeling indices as compared with tumors with labeling indices closer to 0. The overall agreement of MIB-1 labeling indices, while not perfect, was good. The generally minor variability among observers may be related to differences in the area of the slide evaluated and in differing lower thresholds for interpreting positivity. Further improvement of concordance may theoretically be attainable by further training and discussion among observers.

Biomarkers, Tumor↗
PubMed2003

Salivary gland heterotopia in the rectum.

Heterotopic tissues in the submucosal region of the gastrointestinal tract are a well-described occurrence. In the rectal region, these most commonly involve gastric-type mucosa. Only rare reports of salivary gland-type tissue presenting as a submucosal rectal heterotopia have been previously reported. This case report reviews the literature and details an occurrence of heterotopic salivary gland-type tissue in the rectal submucosa of a 31-year-old man who presented with intermittent bleeding and a rectal polypoid mass.

Adult↗
PubMed2003

Comparison of proliferation indices in glioblastoma multiforme by whole tissue section vs tissue microarray.

Tissue microarrays (TMAs) reduce the amount of tissue analyzed with the assumption that protein and gene expression patterns are homogeneous throughout tumors. Many tumor types, including glioblastoma multiforme (GBM), are heterogeneous in many regards, including cell proliferation. We retrospectively compared Ki-67 labeling indices (LIs) determined by whole tissue section (WTS) vs TMA in a series of 50 GBMs from 45 patients. A paired t test indicated that the difference between average LIs obtained from a TMA vs a WTS was not significant (P = .51). There was no correlation between TMA and WTS (r = 0.042; P = .77), indicating that the methods yielded very different results in individual tumors. The Ki-67 LI did not always correlate with the tissue section in an individual tumor; however, when evaluating a large number of tumors on a TMA, the LI range and mean LI were roughly comparable with the LI range and mean LI determined from the WTS.

Adult↗
PubMed2003

The neuropathology of West Nile virus meningoencephalitis. A report of two cases and review of the literature.

West Nile virus (WNV) is an emerging mosquito-transmitted encephalitis virus first recognized in North America in 1999. The pathologic manifestations of WNV infection have not been well defined. This study documents the clinicopathologic features, including autopsy findings, of 2 cases: an 81-year-old man who contracted WNV infection with meningoencephalitis and a polio-like paralysis and a hospitalized 74-year-old woman with meningoencephalitis who acquired WNV through transfusion. The pathologic findings in both cases were marked by perivascular and leptomeningeal chronic inflammation, microglial nodules, and neuronophagia, predominantly involving the temporal lobes and brainstem. These findings also were present in the spinal cord, especially the lumbar region, of the patient with polio-like paralysis. In both cases, most of the inflammatory infiltrate was composed of CD3+ T lymphocytes (a predominance of CD8+ over CD4+ T cells), CD68+ macrophages, and rare CD20+ B lymphocytes. These cases further define the clinical and pathologic spectrum of central nervous system disease in WNV infection.

Aged↗
PubMed2003

Immunohistochemical expression of cathepsin D in meningiomas.

We retrospectively studied the expression of cathepsin D by immunohistochemical analysis in 86 meningiomas (World Health Organization [WHO] grade I, n = 44; WHO grade II, n = 21; WHO grade III, n = 21) and correlated the results with tumor grade and outcome. Staining was scored semiquantitatively based on distribution among neoplastic cells as follows: 0, no staining; 1+, 5% or less of the cells; 2+, 6% to 20%; 3+, 21% to 50%; and 4+, more than 50% of the cells. Cathepsin D expression was observed as follows: 0, 10 cases (12%); 1+, 25 cases (29%); 2+, 15 cases (17%); 3+, 12 cases (14%); and 4+, 24 cases (28%). A higher degree of cathepsin D immunostaining was associated with low tumor grade (P = .0014), low mitotic count (P < .0001), low apoptotic count (P < .0001), and the development of recurrence (P = .035). There was no correlation with outcome or MIB-1 proliferation index. Cathepsin D expression by immunohistochemical analysis was identified in the majority (88% [76/86]) of meningiomas studied. A greater degree of immunoreactivity was observed in the WHO grade I group.

Adolescent↗