Differential expression and cross-talk of peroxisome proliferator-activated receptor γ and retinoid-X receptor α in urothelial carcinomas of the bladder.

PURPOSE: the peroxisome proliferator-activated receptor γ (PPARγ), known to play a key role in homeostatic biological pathways, is also implicated in the process of carcinogenesis. Ligands for PPARγ and its heterodimeric partner, retinoid-X receptor (RXR), have exhibited anticancer effects both in vitro and in vivo. Unexpectedly, some studies suggested that PPARγ ligands may stimulate cancer formation. This study aimed to estimate the signaling of PPARγ-RXRα heterodimer in bladder urothelial carcinomas (BUC). METHODS: we studied PPARγ and RXRα expression in specimens obtained from 97 patients with BUC of various grades and stages using immunohistochemistry. RESULTS: PPARγ expression was significantly downregulated with BUC stage and grade progression, and the dynamics of this phenomenon was significantly influenced by RXRα's level of expression. CONCLUSION: the positive association of PPARγ expression in BUC with more differentiated, non-invasive tumors is strengthened by the presence of RXRα. This knowledge could probably be of use in the development of new chemotherapeutic agents.

The potential role of bcl-2, bax, and Ki67 expression in thymus of patients with myasthenia gravis, and their correlation with clinicopathologic parameters.

OBJECTIVE: The aim of this study was to evaluate bcl-2, bax (apoptotic-oncoproteins), and Ki67 (cell proliferation-marker) expression in thymus of patients with myasthenia gravis (MG) and to determine the potential correlation with clinicopathologic parameters. METHODS: The study was done on 38 patients (16 males, 22 females; mean age 38+/-10 years) with MG who underwent modified maximal thymectomy (MMT). Clinical staging (Osserman classification) included stage I in three, IIA in 19, IIB in 13 and III in three. Microscopic examination of thymus showed thymic hyperplasia in 19, atrophy in eight, thymoma in nine and thymic carcinoma in two. On paraffin sections, the streptavidin-biotin technique, using antibodies to bcl-2, bax, and Ki67, was employed, and in situ hybridization with digoxigenin-labeled probes to bcl-2 and bax was performed. In addition, the apoptotic body index (ABI) was assessed via the TUNEL method. Staining results were correlated with clinicopathologic parameters. RESULTS: Bcl-2 expression was higher in hyperplasia and thymoma cases, compared to thymic carcinomas (P<0.001). Higher expression in carcinomas, compared to hyperplasia and thymomas, was observed for bax (P<0.001), Ki67 (P<0.001) and ABI (P<0.001). Statistical analysis demonstrated: (A) positive correlation of bax+ cells with MG stage (P<0.001), ABI and %Ki67+ cells with MG stage (P<0.001, respectively), %Ki67+ and %bax+ cells with ABI (P<0.05); and (B) reverse correlation between %bcl-2+ cells and MG stage (P<0.05). CONCLUSIONS: In patients with MG who underwent MMT, bcl-2, bax, and Ki67 expression correlates positively or reversibly with the microscopic findings of thymus. Increased apoptosis and proliferation accompany advanced disease stage and possible worse prognosis.

Transforming growth factor-beta(1) and myofibroblasts: a potential pathway towards renal scarring in human glomerular disease.

BACKGROUND/AIMS: The cellular and humoral factors involved in the development and progression of renal scarring have not been fully investigated. Transforming growth factor-beta (TGF-beta(1)) is considered to be the main fibrogenic growth factor and it is implicated in the pathogenesis of renal fibrosis in experimental and clinical nephropathies. On the other hand, collagen III is an important component of the extracellular matrix. In this study we attempted to identify any possible links between TGF-beta(1) and collagen III synthesis and expression with the expression of myofibroblasts in the evolution of renal scarring in human glomerular diseases. METHODS: We studied retrospectively 40 patients with various types of primary and secondary glomerulonephritis (GN), with either proliferative or nonproliferative pattern, with emphasis on the renal synthesis of TGF-beta(1) and collagen III (detected by in situ hybridization) and their expression (detected by immunohistochemistry) as well as myofibroblast expression. The possible links of TGF-beta(1) expression with myofibroblast distribution (alpha-smooth muscle actin, alpha-SMA(+) cells) and with conventional histopathology and renal function was also examined. RESULTS: TGF-beta(1) protein and mRNA were detected in the renal tubular epithelial cells and interstitium and to a lesser extent within glomeruli of patients with GN. Collagen III was mainly detected in the interstitium (peritubular and periglomerular areas) and to a lesser extent in the glomeruli. Messenger RNA for collagen III followed a similar peritubular and periglomerular distribution to that of TGF-beta(1) and alpha-SMA(+) interstitial cells. The intensity of interstitial TGF-beta(1) protein expression was significantly related to the degree of interstitial fibrosis (r = 0.628, p < 0.01), tubular atrophy (r = 0.612, p < 0.01), interstitial collagen III expression (r = 0.478, p < 0.05), and serum creatinine values (r = 0.722, p < 0.001). Also there was a close positive correlation between the severity of interstitial myofibroblast expression and interstitial TGF-beta(1) (r = 0.412, p < 0.05), as well as collagen III (r = 0.409, p < 0.05). In addition, a significant correlation was found between glomerular TGF-beta(1) expression and severity of glomerulosclerosis (r = 0.620, p < 0.01). CONCLUSION: The results of this study suggest that TGF-beta(1) plays an important role in the pathogenesis of fibrosis developing in human kidney, during the evolution of glomerular disease. Interstitial myofibroblasts may contribute to interstitial fibrosis through the synthesis and release of both TGF-beta1 and collagen III.

Expression of bcl-2 and bax in cervical intraepithelial neoplasia and invasive squamous cell carcinoma of the uterine cervix.

Bcl-2 protein together with the pro-apoptotic protein bax, are thought to function by forming homo- and heterotypic dimers which control the progression to apoptosis. In this immunohistochemical study we investigated the expression of bcl-2 and bax apoptosis related proteins in cervical intraepithelial neoplasia and invasive squamous cell carcinoma of the uterine cervix. Twenty-four cervical intraepithelial neoplasias grade 1-2 (CIN I/II), 38 grade 3 (CIN III), and 53 invasive squamous cell carcinomas (ISCC) were investigated by immunohistochemical staining for bcl-2 and bax protein. Bcl-2 immunoreactivity was found in five of the 24 CIN I/II cases (20.8%), 18 of 38 CIN II cases (47.4%) and nine of 53 ISCC cases (17%). The positivity for CIN III was significantly higher than for CIN I/II or ISCC (p=0.0351 and p=0.0018, respectively). The percentage of bax immunopositivity was somewhat higher in CIN III than in CIN I/II but this slight difference was not statistically significant. Correlation of the immunostaining results with tumor grade revealed a significant difference for bcl-2 which was more frequently immunopositive in well-differentiated tumors than in poorly-differentiated tumors. There was no significant relation between bax expression and tumor differentiation. Our results suggest that alterations of bcl-2 and bax expression may occur as a relatively early event in cervical tumorigenesis.

Sources of diagnostic discrepancies in fine-needle aspiration of the breast.

Fine-needle aspiration (FNA) is a valuable technique to use in the evaluation of breast lesions; however, inadequate and discrepant diagnoses do occur. To identify the source and nature of inaccuracies related to the method we studied 39 cases in which FNA posed diagnostic problems. These problems could be attributed to sampling errors (71.8%), to the criteria of adequacy we use at our institution (25.6%), and to interpretation (2.6%). The nature of the breast lesion (68%) was the most common cause of inadequate sampling, followed by the experience of the aspirator (32%).

Tissue imprints in surgical pathology: a rapid intraoperative diagnostic aid.

We studied the intraoperative diagnostic value of imprint cytology in 230 samples obtained from surgical specimens submitted for frozen section diagnosis. A rapid hematoxylin-eosin stain was used. Intraoperative imprint cytology achieved an accuracy rate of 94.3%; for benign lesions the accuracy was 97.5%, and for malignant lesions it was 91%. Overall, the false-negative and suspicious-for-malignancy rates were 1.3% and 4.3%, respectively. No false-positive results were found. The diagnostic yield when intraoperative imprint cytology and frozen section were used together was 99%. It is apparent that imprint cytology is a quick and simple method with wide applicability in the histopathologic diagnosis of lesions from all organs. The value of the method is enhanced when it is used with frozen section diagnosis.

Primary hydatid cyst of the gallbladder.

An unusual case of hydatid cyst of the gallbladder is presented. The difficulties in diagnosis are discussed. There is no other report of such a cyst in the world literature.

Endocrine cells of bronchial and bronchiolar epithelium.

Among the epithelial elements of the pulmonary airways are cells with features suggestive of endocrine function. Although these cells share a number of properties with the intestinal endocrine (argentaffine) cells, peptide hormones analogous to the multitude of those present in the gastrointestinal tract have yet to be identified in the lung. The oat cell carcinoma, which arises from this cell type, is of importance clinically, yet investigations into the basic properties and functions of this cell have been difficult and sparse, in part due to a lack of appreciation of the problem.

Pulmonary alveolar cell carcinoma. Fine structural and in vitro study of a case and critical review of this entity.

Alveolar cell carcinoma is an unusual pulmonary neoplasm composed of cells with the ultrastructural features of granular pneumocytes. In the past this lesion has been grouped with peripheral well-differentiated mucin-secreting adenocarcinomas under the heading of bronchiolo-alveolar cell carcinoma. Because the existence of alveolar cell carcinoma as a distinct entity has been disputed, we examined a case ultrastructurally and confirmed that the neoplastic cells exhibit granular pneumocyte differentiation (lamellar bodies and abundant surface microvilli). In addition, we have growth this tumor in organ culture for up to 5 months and have documented the persistence of granular pneumocyte differentiation during this period. The accumulated evidence from human and animal studies that the granular pneumocyte may undergo neoplastic transformation is briefly reviewed. We conclude that alveolar cell carcinoma is a distinct entity; however, the elucidation of its natural history must await series that separate this lesion from other pulmonary carcinomas.

Oxygen toxicity in the newborn. The effect of chronic continuous 100 percent oxygen exposure on the lungs of newborn mice.

Continuous exposure of newborn mice of a single, highly inbred strain to 100% oxygen at normal atmospheric pressure for up to 6 weeks resulted in a progressive evolution of pulmonary changes which consisted of dense fibrous tissue deposition, chronic bronchitis and bronchiolitis, and emphysema. Survival of the experimental animals decreased with the duration of exposure, and it was 18% after the sixth week. While the pulmonary changes were evolving, lung growth was markedly inhibited in the experimental animals, whereas lung weight increased significantly. The present study indicates that in contrast to the adult mouse, survival of a substantial percentage of newborn mice for at least 6 weeks is possible, but it is associated with severe changes in pulmonary structure that doubtlessly lead to serious derangement of cardiopulmonary functions.

Pulmonary carcinoid tumors is tissue and organ culture.

Pulmonary carcinoid tumors arise from cells whose function is yet to be defined. Conditions for maintenance of cells of these tumors for prolonged periods of time in tissue and organ cultures were established in order to gain insight into their supposed endocrine activity. We succeeded in growing explants of these tumors in organ culture for as long as 5 months without the cells losing their ability to produce large numbers of neurosecretory-type granules.

Bronchopulmonary dysplasia: the pulmonary pathologic sequel of necrotizing bronchiolitis and pulmonary fibrosis.

A light and electron microscopic study was carried out in 21 infants in whom the pathologic diagnosis of bronchopulmonary dysplasia had been made. All the infants except two had the respiratory distress syndrome at birth, and all 21 had been treated with respirator and oxygen therapy for various periods of time. The pathologic alterations observed in all the infants studied were primarily damage of the bronchial and bronchiolar ciliary apparatus and mucous membranes, severe necrotizing bronchiolitis, and marked bronchiolar and alveolar fibrosis. These changes were more pronounced in infants who survived the longest period of time. Such inflammatory and fibrotic changes are known to predispose to destruction of lung tissue, emphysema, and pulmonary hypertension. Six of these 21 infants developed symptoms and signs of cardiac atrial or ventricular stress, including cor pulmonale, prior to their demise. These infants were among those that survived the longest periods of time, had the longest exposure to supplemental oxygen, and showed histopathologically severe pulmonary fibrosis and emphysema.

On the origin of the so-called tumorlets of the lung.

A light and electron microscopic study of multiple tumorlets in a 66 year old female is presented. Clinically the patient had had chronic obstructive lung disease with bronchiectasis of the right upper lobe. Aside from severe bronchiectatic alterations, the resected lobe showed typical tumorlets. On electron microscopic study, these were shown to consist of cells containing large numbers of a neurosecretory type of granule, which was identical to those present in the bronchial counterpart of the intestinal argentaffin (Kulchitsky) cell, as well as in pulmonary carcinoid and oat cell carcinoma cells. Our studies suggest the possibility of a histogenetic relationship between tumorlets, bronchial carcinoid tumors, and oat cell carcinoma, the cell of origin in each case being the bronchial counterpart of the intestinal argentaffin cell.

Peripheral pulmonary carcinoid tumors.

The light microscopic and ultrastructural features of five asymptomatic peripheral carcinoids presented as distinct pulmonary solitary nodules are described. By conventional microscopy the tumors displayed a variety of histologic patterns, the most unusual one showing tumor cells embedded in a richly vascular hyalinized stroma and forming papillary structures or cystic spaces lined by low cuboidal cells which ultrastructurally bore a strong resemblance to intermediate or transitional forms between types I and II pneumocytes. A striking feature of these tumors was their rich vasculature associated with a marked perivascular sclerosis composed of basement membrane-like material and collagen fibrils most likely produced by the increased numbers of pericytes surrounding these sclerotic vessels. The clinical implications, biologic behavior, and association of these tumors with other pulmonary neoplasms are also discussed.

Oxygen toxicity in the newborn. The effect of prolonged 100 per cent O2 exposure on the lungs of newborn mice.

A comprhensive morphologic study of pulmonary oxygen toxicity was undertaken on 78 newborn mice of a single, highly inbred strain continuously exposed to 100 per cent oxygen at normal atmospheric pressure for 7 days. The survival rate was 95 per cent through the first 4 days and 75 per cent through the 7th day. Our findings indicate that response to continuous exposure to 100 per cent oxygen can be divided arbitrarily during the first 7 days into three different phases. During the first, or acute toxic, phase (which generally extends into the 3rd day of exposure), mechanisms, probably adaptive in nature, are sufficiently developed in some of the newborn animals to permit them to survive a continuous 7-day exposure. The acute toxic phase is followed by the critical, high mortality phase, which lasts 3 to 4 days. During this phase, which can be subdivided into a continuum of several stages, the changes seen in the initial, acute toxic phase may progress to more pronouced injury. If the injury is severe, massive pulmonary edema and hemorrhage occur, accounting probably for the deaths of most of the animals in previous similar experimental studies and of 25 per cent of our animals by the 7th day. The second stage of this high mortality phase, being more clearly reactive, consists of a progression of reactive mitochondrial changes, proliferation of granular pneumocytes, and a return to normal of the features of the membranous pneumocytes. The beginning of the third phase, the chronic injury and repair phase, is characterized by the appearance of fibroblasts and a concomitant moderate increase in the amount of collagen.