Biomedical subjects

N Weidner

Publications and source records attributed to N Weidner.

At least 37 records · Page 2Linked to original sources

PubMed2000

Immunohistochemistry of small round-cell tumors.

The term "small round-cell tumor" describes a group of highly aggressive malignant tumors composed of relatively small and monotonous undifferentiated cells with high nuclear to cytoplasmic ratios. This group includes Ewing's sarcoma (ES), peripheral neuroepithelioma (aka, primitive neuroectodermal tumor or extraskeletal ES), peripheral neuroblastoma ("classic-type"), rhabdomyosarcoma, desmoplastic small round-cell tumor, lymphoma, leukemia, small-cell osteosarcoma, small-cell carcinoma (either undifferentiated or neuroendocrine), olfactory neuroblastoma, cutaneous neuroendocrine carcinoma (aka, Merkel-cell carcinoma), small-cell melanoma, and mesenchymal chondrosarcoma. Their clinical presentations often overlap, thus making a definitive diagnosis problematic in some cases. Yet, a clear understanding of their clinicopathologic features usually allows for a confident diagnosis, especially if immunohistochemistry is used. The following is a review of the immunohistochemistry of this small round-cell tumor group.

Biomarkers, Tumor↗

PubMed1999

Nerve growth factor-hypersecreting Schwann cell grafts augment and guide spinal cord axonal growth and remyelinate central nervous system axons in a phenotypically appropriate manner that correlates with expression of L1.

Schwann cells contribute to efficient axonal regeneration after peripheral nerve injury and, when grafted to the central nervous system (CNS), also support a modest degree of central axonal regeneration. This study examined (1) whether Schwann cells grafted to the CNS exhibit normal patterns of differentiation and association with spinal axons and what signals putatively modulate these interactions, and (2) whether Schwann cells overexpressing neurotrophic factors enhance axonal regeneration. Thus, primary Schwann cells were transduced to hypersecrete human nerve growth factor (NGF) and were grafted to spinal cord injury sites in adult rats. Comparisons were made to nontransfected Schwann cells. From 3 days to 6 months later, grafted Schwann cells exhibited a phenotypic and temporal course of differentiation that matched patterns normally observed after peripheral nerve injury. Schwann cells spontaneously aligned into regular spatial arrays within the cord, appropriately remyelinated coerulospinal axons that regenerated into grafts, and appropriately ensheathed but did not myelinate sensory axons extending into grafts. Coordinate expression of the cell adhesion molecule L1 on Schwann cells and axons correlated with establishment of appropriate patterns of axon-Schwann cell ensheathment. Transduction of Schwann cells to overexpress NGF robustly increased axonal growth but did not otherwise alter the nature of interactions with growing axons. These findings suggest that signals expressed on Schwann cells that modulate peripheral axonal regeneration and myelination are also recognized in the CNS and that the modification of Schwann cells to overexpress growth factors significantly augments their capacity to support extensive axonal growth in models of CNS injury.

Animals↗

PubMed1999

Tumour vascularity and proliferation: clear evidence of a close relationship.

Evaluation of various prognostic factors often reveals that some are closely related. In this issue of the Journal of Pathology, evidence is presented linking intratumoural microvessel density with tumour cell proliferation. This is expected, because an adequate blood vascular system is necessary for effective tumour cell proliferation. The blood vascular supply of a tumour is critical not only in providing tumour cells with nutrients, oxygen, and waste elimination, but also because activated endothelial cells release important paracrine growth factors for tumour cells and secrete collagenases, urokinases, and plasminogen activator. The latter allow capillary ingrowth and the spread of tumour cells into and through the adjacent fibrin-gel matrix, connective tissue stroma, and into the lymphatic and/or vascular spaces. Finally, an adequate vascular supply helps to 'switch off' apoptosis and prevent other forms of tumour necrosis, thus contributing to overall tumour growth and spread.

Cell Division↗

PubMed1999

Elimination of basal lamina and the collagen "scar" after spinal cord injury fails to augment corticospinal tract regeneration.

The production of specific extracellular matrix molecules is upregulated following injury to the adult CNS, and some of these molecules have been postulated to inhibit axonal regeneration. In particular, the deposition of collagen in conjunction with basal lamina formation has been correlated with the failure of CNS axons to extend beyond sites of injury. In the present experiment, the spatial and temporal distribution of fibrillar collagen type III and the main constituents of basal lamina (collagen type IV and laminin) were characterized after defined lesions of the adult spinal cord at cervical and thoracic levels. The deposition of collagen was then blocked in animals undergoing defined mid-thoracic spinal cord lesions by administration of the iron chelator 2,2'-bipyridine, and subsequent effects on corticospinal axonal growth were examined. At time points from 1 to 6 weeks postinjury, collagen and laminin were deposited at spinal cord lesion sites as a dense matrix at the host-lesion interface that extended for short distances into the surrounding spinal cord parenchyma. The failure of corticospinal axons to grow beyond the lesioned region correlated spatially and temporally with collagen III formation and basal lamina production. However, successful blockade of collagen and basal lamina formation with 2,2'-bipyridine injections failed to enhance corticospinal axon regeneration or sprouting. These results suggest either that collagen and basal lamina formation after CNS injury do not contribute to corticospinal axonal growth failure or, more likely, that molecules in addition to collagen and basal lamina contribute to axonal growth failure and must be collectively blocked to promote corticospinal regeneration.

2,2'-Dipyridyl↗

PubMed1999

Prognostic markers in resected stage I and II non small-cell lung cancer: an analysis of 260 patients with 5 year follow-up.

We performed a retrospective analysis of potential prognostic markers in 260 patients with surgically resected stage I and II non small-cell lung cancer (NSCLC) with a minimum 5-year follow-up. Cox proportional hazard models and Wilcoxon tests were employed to analyze the effect of patient characteristics on survival and disease-free survival (DFS). In the univariate analysis, the following were significant predictors of shorter overall survival: N-stage (N1 vs N0) (p<0.001); T-stage (T2 vs T1) (p<0.001); antigen A (loss vs presence) (p<0.01); cough (present vs absent) (p=0.01); bcl-2 expression (positive vs negative) (p=0.03); age (>63.5 vs <63.5) (p=0.03); mucin (positive vs negative) (p<0.03). The following were significant predictors of shorter DFS: N-stage (p<0.001); T-stage (p=0.001); loss of antigen A (p=0.01); mucin expression (p<0.01); cough (p=0.02); Ki-67 expression (p=0.02) and negative bcl-2 expression (p=0.03). Analysis of survival difference for histologic subtype, degree of differentiation, aneuploidy, %S-phase, codon 12 K-ras mutation, and immunohistochemistry staining for Lewisy, p53, Rb, microvessel count, HER2, E-cadherin and neuroendocrine markers did not reach statistical significance. In multivariate analysis, the following predicted for shorter overall survival: N-stage (p<0.01), antigen A (p=0.01), age (p<0.01), and bcl-2 (p=0.05); and for DFS, N-stage (p<0.01), antigen A (p<0.01), Ki-67 (p=0.03), mucin (p=0.04) and T-stage (p=0.05). Of all the clinical-pathological, proliferative, and biological markers studied, only a few carried independent prognostic significance.

Journal Article↗

PubMed1999

Germ-cell tumors of the mediastinum.

Mediastinal germ-cell tumors (GCTs) usually occur within the anterior mediastinum, accounting for about 15% of all mediastinal cysts and tumors. They are associated with the thymus, presumably arising from extragonadal germ cells or thymic cells with germ-cell potential. Mediastinal seminoma develops primarily in young males with rare cases reported in females; likewise, embryonal carcinoma, endodermal sinus tumor or yolk-sac tumor, choriocarcinoma, and malignant mixed or combined GCTs also overwhelmingly affect males. Mature cystic teratoma affects males and females equally. The prognosis for mediastinal mature cystic teratoma and seminoma is very good. Nonseminomatous malignant GCTs of the mediastinum often present with advanced disease and do not respond as well to chemotherapy as their gonadal counterparts. Nonetheless, it is important to separate mediastinal GCTs from other undifferentiated malignant tumors, especially thymic carcinoma, which has a poor prognosis. Clearly, some patients with mediastinal GCTs respond very well to modern therapies.

Adolescent↗

PubMed1998

Tumoural vascularity as a prognostic factor in cancer patients: the evidence continues to grow.

Accurate prognostic indicators would help in identifying patients at high risk for recurrence and death. Recent and previous studies indicate that intratumoural microvessel density (iMVD) of invasive breast carcinoma (a measure of tumour angiogenesis) is associated with aggressive tumour growth; iMVD may thus be a valuable prognostic indicator. Moreover, the bulk of accumulating data indicates that microvessel density in the area of most intense neovascularization in invasive breast carcinoma is an independent, significant and accurate prognostic indicator in predicting poorer survival. Such an indicator would be useful in the selection of high-risk patients with breast carcinoma for systemic adjuvant therapy.

Breast Neoplasms↗

PubMed1998

BDNF and TrkB expression in intrastriatal ventral mesencephalic grafts in a rat model of Parkinson's disease.

We investigated the expression of BDNF and its high affinity receptor trkB in fetal dopaminergic grafts in a rat model of Parkinson's disease. Grafts were allowed to differentiate for 7, 14, 28, or 56 days, respectively and were analyzed immunocytochemically thereafter with antibodies directed against tyrosine hydroxylase, BDNF and trkB. At all time points investigated, grafts contained tyrosine hydroxylase immunoreactive neurons. Immature grafts (7 days) displayed no immunoreactivity for BDNF which was restricted to glial cells at the graft-host interface. After longer differentiation periods BDNF-immunoreactivity was detectable in neurons and astrocytes within the grafts. No trkB immunoreactivity was found in immature grafts but a strong signal for trkB emerged in grafted neurons older than 14 days whereas glial cells remained unlabeled at all time points investigated. Expression of BDNF and trkB in grafted neurons and of BDNF in surrounding glial cells suggests an autocrine or paracrine action of BDNF on dopaminergic neurons possibly mediated by activated glia.

Animals↗

PubMed1998

Prognostic significance of Ki-67 immunostaining and symptoms in resected stage I and II non-small cell lung cancer.

The proliferative rate of a tumor has been considered predictive of its clinical course. We evaluated the expression of the proliferative marker Ki-67 and its relationship to survival, disease-free survival and other clinicopathologic variables in both stage I and stage II non-small cell lung cancer (NSCLC). A total of 260 patients with surgically resected stage I (n = 193), and II (n = 67) NSCLC with at least 5 years follow-up were identified. The median survival for patients with low expression of Ki-67 (< or = 25%) was 54 months, while for those with high expression (> 25%), it was 45 months (P = 0.1). The disease-free survival in patients with low expression of Ki-67 was 59 months while it was only 32 months for patients with high Ki-67 (P = 0.1). Out of 136 patients, 84 (62%) had both increased S-phase (> 8%) and high Ki-67 (P = 0.001). A total of 28 of 30 patients who had loss of antigen A had high expression of Ki-67 (93.3%) (P = 0.03). Ki-67 expression was also higher in squamous cell (54/63, 85.7%) compared to nonsquamous cell cancer (70/108, 64%) (P = 0.03). We also analyzed for the presence of symptoms with survival. The presence of symptoms was not found to be statistically significant, for overall survival (P = 0.33) or disease-free survival (P = 0.72). When individual symptoms were analyzed, the presence of cough was statistically significant for both overall and disease-free survival. The median survival was 39 months for patients with cough, and 57 months for patients without cough (P = 0.04). Multivariate analysis showed higher N and T stages, presence of cough and loss of antigen A, predicted for poorer overall survival. Higher N and T stages, loss of antigen A, presence of mucin and cough and increased expression of Ki-67 predicted decreased disease-free survival. Although we did not find a statistically significant difference between low and high Ki-67, there was a trend for a poorer overall and disease-free survival in patients with high Ki-67 expression. Larger studies may be needed to prove a statistically significant effect of Ki-67 on survival. Future studies should assess the potential prognostic significance of the presence of symptoms (particularly cough) in addition to clinical-pathologic variables (such as T and N stage) and biological markers in patients with early stage NSCLC.

Aged↗

PubMed1997

Genetic alterations in lobular breast cancer by comparative genomic hybridization.

Infiltrating lobular carcinoma (ILC) and infiltrating ductal carcinoma (IDC) are distinguished by their histopathological appearance. However, little is known about the differences in genetic changes between lobular cancers and ductal cancers. We used comparative genomic hybridization (CGH) and compared aberrations in 19 ILCs and 46 IDCs. The total number of aberrations was lower in ILC than in IDC. While the average number of DNA copy number losses did not reach significance between them, copy number gains were significantly lower in ILCs. Fifteen of 19 ILCs (79%) showed increased copy number of 1q, and 12 cases (63%) revealed loss of 16q. The presence of these aberrations was independent of nodal status, histologic subtypes (pleomorphic or classic ILC), or BrdUrd-labeling index. ILCs had a higher frequency of 16q loss than did ductal cancers, and a lower frequency of 8q and 20q gains. Our data suggest that the altered growth pattern and clinical presentation which characterize infiltrating lobular cancers are correlated with distinct genetic alterations.

Adult↗

PubMed1997

Collision tumor: a peripheral neuroepithelioma and a transitional-cell carcinoma occurring simultaneously in the renal pelvis.

We report a unique case of a collision tumor of the kidney composed of a peripheral neuroepithelioma (PNE) and a transitional cell carcinoma (TCC) that occurred in a 67-year-old man with a long history of superficial TCC of both the bladder and bilateral upper urinary tracts. The PNE was composed of hyperchromatic, small, round cells, arranged in clusters and poorly cohesive sheets. Immunohistochemical studies revealed the small cells to be strongly positive for O13 (ie, a MIC2 gene product stain [CD99]) and vimentin. Electron microscopic examination found numerous interdigitating cell processes, multiple poorly formed cell-cell junctions, and dense-core granules. The latter were most conspicuous at the tips of the cell precesses. The PNE cells were clearly negative for cytokeratin, and they showed no transitional or intermediate features that would suggest evolution of the PNE from the adjacent TCC. The proximity of these two tumors appears to be serendipitous; thus, it can be considered a true collision tumor of the kidney.

12E7 Antigen↗

PubMed1997

The insulin receptor content is increased in breast cancers initiated by three different oncogenes in transgenic mice.

The Insulin Receptor (IR) is a potential oncogene for mammary epithelial cells since its content is increased in most human breast cancer specimens, and both ligand-dependent malignant transformation and ligand-dependent enhanced growth occurs in cultured breast cells overexpressing the IR. To better understand whether the IR plays a role in mammary carcinogenesis which is independent of other initiation factors, we measured IR content in transgenic mouse models of breast cancer induced by 3 known oncogenes (Wnt-1, Neu, and Ret). Insulin receptor content was measured by a specific radioimmunoassay. In normal mammary gland tissues IR content was 14.6 +/- 1.4 ng/mg of protein (mean +/- SEM, n = 6). In the 3 cancers IR content was elevated (Neu = 36.1 +/- 4.6, n = 8, p < 0.002; Wnt-1 = 38.3 +/- 2.6, n = 13, p < 0.001; and Ret = 53.6 +/- 7.1, n = 7, p < 0.001). These data indicate that IR overexpression, in addition to being a potential oncogene, is increased in mouse tumors initiated by other oncogenes, and therefore may also play a supportive role in the growth of breast cancers.

Animals↗

PubMed1997

Hodgkin's disease of the esophagus.

A 61-year-old man with acquired immunodeficiency syndrome (AIDS) sought care because of the onset of progressive dysphagia. He was found to have a perforated, fungating esophageal mass. The combined histologic and immunologic findings were diagnostic of Hodgkin's disease, nodular sclerosis type, lymphocyte-depleted variant, arising in the esophagus. The Reed-Sternberg cells and mononuclear variants were positive for Epstein-Barr virus (EBV) latent membrane protein (LMP1) and EBV RNA. Occasional small lymphoid cells were also positive for EBV RNA. Polymerase chain reaction studies demonstrated the presence of EBV type A without deletion of the EBV LMP1 gene. Other authors have reported an increased frequency of type B EBV and deletion of the EBV LMP1 gene in cases of human immunodeficiency virus-associated Hodgkin's disease. Hodgkin's disease arising in the esophagus is rare in immunocompetent patients. However, in the presence of AIDS, Hodgkin's disease should be considered in the differential diagnosis of patients with signs or symptoms of esophageal disease.

Acquired Immunodeficiency Syndrome↗

PubMed1997

Diabetes insipidus from sarcoidosis confined to the posterior pituitary.

A young white man with new-onset central diabetes insipidus was discovered to have a posterior pituitary mass on magnetic resonance imaging. No other radiological abnormalities were noted in the anterior pituitary, infundibulum or hypothalamus. No other endocrinopathies were present: laboratory investigations showed normal basal concentrations of anterior pituitary hormones, including prolactin. The patient was suspected to have sarcoidosis affecting the posterior pituitary, because of the discovery of pulmonary sarcoidosis during his diagnostic evaluation. His symptoms of polydipsia and polyuria responded promptly to intranasal administration of 1-desamino-8-D-arginine vasopressin (DDAVP). The patient demonstrated complete regression of the posterior pituitary mass after a course of corticosteroid therapy. However, his diabetes insipidus persisted and he continues to need DDAVP treatment, currently at 12 months of follow-up. The resolution of the neurohypophysial mass was compatible with the diagnosis of pituitary sarcoidosis and this precluded the need for a transsphenoidal biopsy or surgery.

Adrenal Cortex Hormones↗

PubMed1997

Pathologic prognostic factors for patients with breast carcinoma. Which factors are important.

Current technologies can identify subsets of patients who are at greater risk for developing recurrent carcinoma. This article presents conventional and generally accepted pathologic features of breast carcinoma that allow breast carcinoma patients to be placed into low-risk or high-risk categories for recurrence-free or overall survival. Also, the role of flow cytometry, estrogen-progesterone receptor measurement, tumor angiogenesis, and selection oncoprotein expression, such as c-erbB2, are reviewed.

Breast Neoplasms↗

PubMed1997

Relationship of tumor angiogenesis and nuclear p53 accumulation in invasive bladder cancer.

The purpose of this investigation was to evaluate the relationship between tumor angiogenesis and nuclear p53 accumulation in invasive bladder cancer. We studied 161 patients with invasive transitional cell carcinoma of the bladder who had previously undergone radical cystectomy. Analysis was performed to determine the presence of p53 nuclear accumulation and extent of tumor-associated angiogenesis. p53 status identified a group of patients at high risk for tumor progression (p53-altered tumors), and microvessel density determinations added additional prognostic information by identifying a subset of aggressive tumors within the wild-type p53 subgroup. At 5 years, patients with tumors exhibiting no evidence of p53 alterations and low microvessel counts demonstrated 3% recurrence and 88% survival, compared to 43% recurrence and 59% overall survival for patients with intermediate vessel counts and 61% recurrence and 43% overall survival for patients with the highest vessel counts (P < 0.001 and P = 0.003, respectively). Angiogenesis also provides additional prognostic information to patients with tumors that demonstrate p53 alterations. An association between angiogenesis and p53 status did exist (P = 0. 05); however, 27% of the tumors that showed no evidence of p53 alterations exhibited high microvessel counts, and 26% of tumors with evidence of p53 alterations had low microvessel counts. Tumor-associated angiogenesis adds additional useful prognostic information to that which is obtained from p53 status in patients with invasive transitional cell carcinoma of the bladder. Although an association between p53 status and the degree of angiogenesis was identified, other factors appear to play a role in the regulation of tumor-induced neovasularization.

Biomarkers, Tumor↗

PubMed1996

New prognostic factors in nasopharyngeal carcinoma. Tumor angiogenesis and C-erbB2 expression.

BACKGROUND: This study was conducted to determine the prognostic significance of tumor angiogenesis, c-erbB2, epidermal growth factor receptor, Ki-67, and p53 for patients with nasopharyngeal carcinoma. METHODS: In this retrospective study, the authors retrieved clinical data and made immunohistochemical preparations on archival tissue specimens from 30 patients with nasopharyngeal carcinoma treated with radiation therapy at the University of California at San Francisco between 1956 and 1990. The pretreatment clinical and immunohistochemical data were correlated with cervical lymph node metastasis at diagnosis, and endpoints including development of locoregional failure, distant metastasis, disease free survival, and overall survival. RESULTS: Intense tumor angiogenesis, defined as microvessel counts for 60 or more microvessels per 200 x field correlated with the development of distant metastasis (P = 0.03), shorter overall survival (P = 0.02), and disease free survival (P = 0.05). Strong c-erbB2 expression correlated with a shorter overall survival (P = 0.02) and disease free survival (P = 0.02). Stage IV disease (P = 0.04) and the presence of cervical lymph node metastasis (P = 0.05) correlated with a shorter overall survival. A duration of symptoms of fewer than 6 months correlated with a shorter disease free survival (P = 0.05). No association was observed between any of the biologic prognostic factors and lymph node involvement or locoregional failure. CONCLUSIONS: The results of this study show that the tumor angiogenesis and c-erbB2 expression are significant prognostic indicators for patients with nasopharyngeal carcinoma. The presence of cervical lymph node metastasis, Stage IV disease, and a duration of symptoms fewer than 6 months also indicate a poor prognosis. The authors did not find any prognostic significance for epidermal growth factor receptor, Ki-67, or p53. These results suggest that tumor microvessel counts and c-erbB2 may be useful in identifying patients who may benefit from systemic chemotherapy or other novel treatment strategies.

Adolescent↗

PubMed1996

Post-irradiation malignant mesothelioma.

BACKGROUND: Approximately 30 patients with malignant mesothelioma following radiotherapy have been described. Population-based studies of this occurrence have not been reported. METHODS: Patients with malignant mesothelioma of the pleura were collected. All of the patients had a prior cancer and had received radiotherapy to the region in which the malignant mesothelioma developed. Data from the National Cancer Institute's Surveillance, Epidemiology and End Results Program and the Connecticut Tumor Registry were evaluated for cases of malignant mesothelioma of the pleura occurring in patients with a previous cancer. The literature on post-irradiation malignant mesotheliomas was reviewed. RESULTS: Eight patients (4 men, 4 women) with malignant mesothelioma occurring in sites of radiotherapy for a prior tumor were identified. The mean age at diagnosis of mesothelioma was 45 years (range: 22-78 years), and the average interval between radiotherapy and the mesothelioma was 21 years (range: 11-29 years). Three of the patients had also received chemotherapy. Histologically, the mesotheliomas were epithelial in five cases, biphasic in one, and sarcomatous in one. One hundred forty-two patients were identified in the epidemiologic survey. The majority were men (89%), with a mean age for all patients of 68.5 years (range: 35-86 years) and a median latency between first cancer and mesothelioma of 4.3 years (range: 2 months-29.9 years). CONCLUSIONS: Mesotheliomas rarely develop as second malignant neoplasms. Within a large, population-based survey of patients with cancer, temporal patterns and demographic features of most second primary mesotheliomas were similar to asbestos-related tumors, although the late effects of cancer treatment might have contributed to the occurrence of cancer in some patients.

Adult↗