The spatial relationship between stem cells and their progeny in the basal layer of human epidermis: a new view based on whole-mount labelling and lineage analysis.
(17/3039)
In order to examine the spatial organisation of stem cells and their progeny in human epidermis, we developed a method for whole-mount epidermal immunofluorescence labelling using high surface beta1 integrin expression as a stem cell marker. We confirmed that there are clusters of high beta1 integrin-expressing cells at the tips of the dermal papillae in epidermis from several body sites, whereas alpha6 integrin expression is more uniform. The majority of actively cycling cells detected by Ki67 or bromodeoxyuridine labelling were found in the beta1 integrin-dull, transit amplifying population and integrin-negative, keratin 10-positive cells left the basal layer exclusively from this compartment. When we examined p53-positive clones in sun-exposed epidermis, we found two types of clone that differed in size and position in a way that was consistent with the founder cell being a stem or transit amplifying cell. The patterning of the basal layer implies that transit amplifying cells migrate over the basement membrane away from the stem cell clusters. In support of this, isolated beta1 integrin-dull keratinocytes were more motile on type IV collagen than beta1 integrin-bright keratinocytes and EGFP-labelled stem cell clones in confluent cultured sheets were compact, whereas transit amplifying clones were dispersed. The combination of whole-mount labelling and lineage marking thus reveals features of epidermal organisation that were previously unrecognised. (+info)
Prognostic significance of angiogenesis and Ki-67, p53, and p21 expression: a population-based endometrial carcinoma study.
(18/3039)
PURPOSE: For endometrial carcinoma patients, there is a need for improved identification of high-risk groups that may benefit from postoperative adjuvant therapy. We therefore studied the prognostic impact of markers for cell proliferation, cell-cycle regulation, and angiogenesis among endometrial carcinoma patients in a population-based setting. PATIENTS AND METHODS: All patients diagnosed with endometrial carcinoma between 1981 and 1985 in Hordaland County, Norway, were studied. The median follow-up for the survivors was 11.5 years (range, 8 to 15 years), with no patient lost because of insufficient follow-up information. Paraffin-embedded tumor tissue, available in 96% of the cases (n = 142), was studied immunohistochemically for microvessel density (MVD) and expression of Ki-67, p53, and p21 proteins. We used the hot spot method for calculation of MVD, and expression of Ki-67 and p21 protein, because this approach may increase the probability of detecting small aggressive clones of possible prognostic relevance. The importance of these tumor markers was investigated in univariate survival analyses and Cox regression analysis. RESULTS: The majority of traditional clinicopathologic variables was significantly associated with the tumor biomarkers. Age, International Federation of Gynecology and Obstetrics (FIGO) stage, histologic type, histologic grade, MVD, as well as Ki-67, p53, and p21 protein expression, all significantly influenced survival in univariate analyses (P < or = .05). In the Cox regression analysis, age, FIGO stage, MVD, Ki-67 expression, and p53 expression were the only variables with independent prognostic impact (P < or = .05), whereas histologic type, histologic grade, and p21 expression had no independent influence. A group of high-risk patients with more than one unfavorable marker was identified. CONCLUSION: In addition to age and FIGO stage, MVD, Ki-67, and p53 protein expression showed an independent prognostic impact. Thus, information derived from routine histologic specimens identified a subgroup of high-risk endometrial carcinoma patients in this population-based study. (+info)
Significance of myocytes with positive DNA in situ nick end-labeling (TUNEL) in hearts with dilated cardiomyopathy: not apoptosis but DNA repair.
(19/3039)
BACKGROUND: The presence of apoptotic myocytes has been reported in human hearts with dilated cardiomyopathy (DCM) on the basis of a positive finding of DNA in situ nick end-labeling (TUNEL). However, ultrastructural evidence of myocyte apoptosis has not been obtained. METHODS AND RESULTS: A total of 80 endomyocardial biopsies were obtained from right and left ventricles of 20 patients with DCM and 20 normal control subjects. TUNEL-positive myocytes were found by light microscope in 15% of DCM specimens (controls, 0%, P<0.05), and the percentage of TUNEL-positive myocytes per section in DCM was 1. 0+/-2.7% (mean+/-SD). According to TUNEL at the electron microscopic level (EM-TUNEL), immunogold particles, which label DNA breaks with 3'-OH terminals, were markedly accumulated in the bizarre-shaped nuclei, with widespread clumping of chromatin (so-called "hypertrophied nuclei") of the myocytes obtained from DCM. Their ultrastructure was neither apoptotic nor necrotic but rather that of living cells. Taq polymerase-based DNA in situ ligation assay, which detects double-stranded DNA fragments more specifically than TUNEL, did not detect a positive reaction in any case. In mirror sections, all of the TUNEL-positive myocytes in DCM simultaneously expressed proliferating cell nuclear antigen, which is required for both DNA replication and repair, but Ki-67, a replication-associated antigen, was completely negative in all cases, which appeared to rule out cell proliferation activity. CONCLUSIONS: Most of the TUNEL-positive myocytes in hearts with DCM are not apoptotic but rather living cells with increasing activity of DNA repair. (+info)
Paradoxical correlations of cyclin-dependent kinase inhibitors p21waf1/cip1 and p27kip1 in metastatic colorectal carcinoma.
(20/3039)
The cyclin-dependent kinase inhibitors (CDIs) p27kip1 and p21waf1/cip1 are key cell cycle-negative regulatory enzymes. The objective of this study was to correlate expression of p27kip1 and p21waf1/cip1 with survival, chemotherapy responsiveness, and expression of the proliferation marker Ki-67 in patients with advanced colorectal cancer. Immunohistochemistry was performed with antibodies to p27kip1, p21waf1/cip1, and Ki-67 on samples from 66 patients with metastatic colorectal carcinoma. Interpretation was performed by visual inspection and automated image analysis. Patients who obtained a response to chemotherapy had greater p21waf1/cip1 tumor staining with a mean of 10.0 positive cells/high-powered field, compared with 4.5 positive cells/high-powered field for nonresponders (P = 0.03). A positive Spearman correlation was seen between Ki-67 and p27kip1 (r = 0.48; P = 0.0001), as well as between Ki-67 and p21waf1/cip1 (r = 0.48; P = 0.0001). A trend toward shorter survival was seen in patients with positive specimens (median survival of 10 months for patients with both p27kip1- and p21waf1/cip1-positive specimens, compared with 22 months for patients with neither p27kip1- nor p21waf1/cip1-positive specimens). In contrast to that previously reported in normal colonic mucosa or early-stage colorectal cancer, we observed positive correlations of Ki-67 with both p27kip1 and p21waf1/cip1, a trend toward greater CDI staining indicating worse prognosis, and greater p21waf1/cip1 staining in tumors that were chemosensitive. These findings suggest that in the metastatic setting, CDIs may show altered function, compared with their role in the normal cell cycle. (+info)
Suppression of the neoplastic phenotype by transfection of phospholipase C beta 3 to neuroendocrine tumor cells.
(21/3039)
The expression of phospholipase C beta 3 (PLCB3) is low or absent in several neuroendocrine neoplasias. To investigate the role of PLCB3 in the neuroendocrine tumorigenesis, we transfected a PLCB3 construct to three neuroendocrine tumor cell lines with a low PLCB3 expression. The growth rate and tumorigenicity were assessed in vitro by [3H]thymidine incorporation and cell counting, in vivo, by xenografting to nude mice. In vitro, PLCB3 expressing clones showed a significant growth inhibition. The tumor weight was reduced for one of the two xenografted PLCB3-transfected cell lines and in both, a reduced number of proliferating (Ki-67 positive) cells was observed. This study implies an essential role for PLCB3 in the neuroendocrine tumorigenesis. (+info)
Effects of the neurotrophin brain-derived neurotrophic factor in an experimental model of retinal detachment.
(22/3039)
PURPOSE: To examine the effects of brain-derived neurotrophic factor (BDNF) in an animal model of retinal detachment. METHODS: Cat retinas were detached from the retinal pigment epithelium for either 7 or 28 days. Animals received either an intravitreal injection of BDNF (100 ILg) or phosphate-buffered saline (PBS), the vehicle for BDNF. Retinas were evaluated using morphology and immunocytochemistry. The width of the outer segment zone was measured, and the retinas were evaluated for changes in protein expression by labeling with antibodies to rod opsin, phosducin, synaptophysin, calbindin D, and glial fibrillary acidic protein (GFAP). The effect of BDNF on both proliferation and apoptotic cell death was examined. RESULTS: Although there was variability in the treated retinas, most of the animals receiving BDNF had well-organized outer segments that were longer than those in vehicle-treated controls. Immunocytochemistry revealed that treated retinas had consistently less opsin redistribution to the plasma membrane, less phosducin upregulation, and fewer calbindin D-labeled horizontal cell processes. BDNF did not reduce overall cell death in the detachments or death of photoreceptors by apoptosis. However, it significantly reduced the proliferative response of Miller cells and the extent of upregulation of GFAP. CONCLUSIONS. The results suggest that BDNF may aid in the recovery of the retina after reattachment by maintaining the surviving photoreceptor cells, by reducing the gliotic effects in Muller cells, and perhaps by promoting outer segment regeneration. (+info)
Mono- and plurihormonal thyrotropic pituitary adenomas: pathological, hormonal and clinical studies in 12 patients.
(23/3039)
In a series of 12 patients (eight women and four men, aged between 20 and 62 years), operated on for a pituitary adenoma shown to be thyrotropic by immunocytochemistry, we performed a retrospective and comparative analysis of clinical and biological data, tumor studies including immunocytochemistry with double labeling, and proliferation marker (proliferative cell nuclear antigen (PCNA) and Ki-67) detection, electron microscopy and culture. Our study leads us to confirm that thyrotropic tumors are rare (12 of 1174 pituitary adenomas: 1%). The main points arising were that: (1) high or normal plasma TSH associated with an increase in plasma alpha-subunit and high thyroid hormone levels is the best criterion for diagnosis; (2) the failure of TSH to respond to TRH or Werner's test is not a reliable criterion for diagnosis; (3) thyrotropic adenomas may be 'silent', without clinical signs of hyperthyroidism and with only slight increase in TSH, tri-iodothyronine and thyroxine concentrations; (4) mitoses and nuclear atypies are frequently detected in large tumors, which are invasive in more than 50% of cases - the first analysis of two proliferation markers (PCNA and Ki-67) bears out the relative aggressiveness of thyrotropic adenomas; (5) thyrotropic adenomas are frequently plurihormonal. Immunocytochemical double labeling, complemented by in vitro study, showed that thyrotropic tumor cells sometimes can or sometimes cannot cosecrete TSH, GH or prolactin. The pathological identification of monohormonal and plurihormonal adenomas seems to be supported by clinical and biological differences. (+info)
Cyclin D1 expression in non-small-cell lung cancers: its association with altered p53 expression, cell proliferation and clinical outcome.
(24/3039)
Cyclin D1, like p16INK4 (p16) and retinoblastoma (RB) proteins, participates in the cell cycle control at the G1-S transition. We have previously demonstrated altered p16 and RB protein status in non-small-cell lung cancers (NSCLCs) and their potential synergistic effect with altered p53 protein on proliferative activity (Kinoshita et al (1996) Cancer Res 56: 5557-5562). In the present study, cyclin D1 expression was studied by immunohistochemistry in the same cohort of 111 resected NSCLCs as in our previous study, and the amount of the cyclin D1 gene was analysed by Southern blot analysis in 29 NSCLCs. Cyclin D1 expression was analysed in relation to the status of p53, p16 and RB proteins, and proliferative activity determined by the Ki-67 index. It was also analysed in relation to survival of 77 patients with NSCLCs which were potentially curatively resected between 1990 and 1995. We found that: (1) cyclin D1 was expressed in 13 (11.7%) of 111 NSCLCs; (2) the cyclin D1 gene was neither significantly amplified nor rearranged; (3) cyclin D1 expression significantly correlated with altered p53 protein expression (P = 0.04), whereas it did not correlate with p16 and RB protein status; (4) proliferative activity tended to be higher in cyclin D1-positive (+) tumours than in cyclin D1-negative (-) tumours, although this difference was not statistically significant (P = 0.08); and (5) patients with cyclin D1+ tumours survived longer than patients with cyclin D1- tumours (5-year survival rates, 89% and 64% respectively, by the Kaplan-Meier method; P = 0.045 by the log-rank test), and cyclin D1 expression tended to be a favourable prognostic factor (P = 0.08 in univariate analysis). These findings suggest the involvement of cyclin D1 in the development and progression of NSCLCs, their proliferative activity and clinical outcome of NSCLC patients. (+info)