Biomedical subjects

E Patsouris

Publications and source records attributed to E Patsouris.

66 records · Page 4Linked to original sources

PubMed1989

Bacterial lymphadenitis with the picture of a lymphoepithelioid cell lymphoma--Lennert's lymphoma.

Three cases with the typical light microscopic picture of lymphoepithelioid cell lymphoma (so-called Lennert's lymphoma) were investigated by electron microscopy. Surprisingly, Lennert's lymphoma could be excluded in two cases. These two cases exhibited, in addition to pleomorphic lymphocytes and epithelioid cells, macrophages with accumulations of bacteria, indicating that a bacterial infection was the cause of the disease. By comparing the typical case of Lennert's lymphoma with the other cases, we found several criteria for distinguishing between Lennert's lymphoma and bacterial lymphadenitis. In bacterial lymphadenitis: (1) small and medium-sized lymphocytes exhibited a wide cytological spectrum whereas the lymphocytes in Lennert's lymphoma were relatively uniform; the lymphocytes with prominent lysosome-like granules found in Lennert's lymphoma were not seen; (2) cytology and distribution of epithelioid cells were similar to those in Lennert's lymphoma; (3) epithelioid venules contained recirculating lymphocytes, which were rarely found in Lennert's lymphoma; (4) numerous interdigitating reticulum cells, fibroblasts and myofibroblasts were seen, but not in Lennert's lymphoma; (5) focal increase in reticulin fibres was the main difference in light microscopy; (6) rod-shaped bacteria were accumulated in the cytoplasm of a few macrophages. The presence of bacteria could not be demonstrated unequivocally by light microscopy. In both cases the large number of intracytoplasmic bacteria suggests that this unusual and until now unknown lymphadenitis is the result of an infection caused by facultative intracellular parasitic bacteria. The outcome of bacterial lymphadenitis that gives the false impression of Lennert's lymphoma is uncertain. Cure was achieved in one of our cases. The other patient died before therapy was commenced.

Adult↗

PubMed1988

Histological and immunohistological findings in lymphoepithelioid cell lymphoma (Lennert's lymphoma).

Four hundred and two cases considered or suspected to be lymphoepithelioid cell lymphoma (Lennert's lymphoma) were analyzed morphologically, immunohistochemically, and clinically. One hundred and eight of these cases, investigated in 180 biopsies, fulfilled the morphological and immunohistochemical criteria for lymphoepithelioid cell lymphoma and are herein reported. Cellular composition and histological structure are described in detail as a basis for discriminating Lennert's lymphoma from similar lymphomas with a high content of epithelioid cells (Hodgkin's disease, AILD type of T-cell lymphoma, lymphoplasmacytic lymphoma) and from inflammatory epithelioid cell reactions. Single typical Hodgkin cells were found in only 3.8% of biopsy specimens examined, and single typical Sternberg-Reed cells were found in only 2.2% of the biopsy specimens examined. Because these single Hodgkin and Sternberg-Reed cells were situated in a relatively monotonous lymphoid cellular pattern and because both these cells types also may occur in peripheral T-cell lymphomas, we include cases with such cells in the category of Lennert's lymphoma. Eight percent of the patients with lymphoepithelioid cell lymphoma showed transformation into a large-cell T-cell lymphoma without the prominent focal epithelioid cell component previously observed. Immunohistochemically, seven of the 69 biopsy specimens with detectable giant cells stained positively for the granulocyte-specific monoclonal antibody 3C4 (approximately CD15). Plasma cells were rare and always showed a polytypic immunoglobulin pattern. Lymphoepithelioid cell lymphoma, defined as a lymphoma of CD4+ T lymphocytes, marks the border between Hodgkin's disease and the non-Hodgkin's lymphomas. Today, absolute criteria for distinguishing between these two classes of lymphoma are lacking.

Antibodies, Monoclonal↗

PubMed1988

[Comparative immunohistochemical study of lysozyme and lactoferrin in human neonate and adult parotid glands].

Lysozyme and lactoferrin, substances of the non-specific defense system of the salivary glands, were studied in normal human parotid glands of neonates and adults using the immunoperoxidase method. To our knowledge, the immunohistochemical detection and distribution of lysozyme and lactoferrin in neonate parotid glands have not been previously reported. In neonate parotid glands, a monotonous positive reaction for lysozyme was found in the acini, in the intercalated ducts and in a few cells of large ducts. On the contrary, lysozyme was observed mainly in the intercalated ducts of the adult parotid glands. Three staining patterns for lactoferrin were found in neonate parotid glands. The first pattern was identical to that of lysozyme in neonates, the second was similar to that of lactoferrin in adults, and in the third extremely few acinar and intercalated duct cells were positive. In adult parotid glands, lactoferrin was detected in groups of acini and intercalated ducts and rarely striated duct cells. In adult parotid glands, our findings are discussed in correlation with those of other investigators. The results of our study indicate that lysozyme and lactoferrin have an important role in the defense mechanism of neonate parotid gland. There is also a distinct immunohistochemical difference between neonate and adult parotid gland. Since it is known that there is a morphological differentiation of the parotid gland postnatally, it is presumably suggested that an immunohistochemical differentiation also occurs.

Adult↗

PubMed1983

[Experimental administration of di-N-butyl-nitrosamine (DBN) in rats. Carcinogenic activity in the urinary bladder].

Di-N-butyl-nitrosamine (DBN) was administered in a suspension with dimethylsulfoxide (DMSO) to 80 rats in doses of 10 and 40 mg/kg/day. The carcinogen was given to the animals in groups of 40 either orally or subcutaneously. The animals were exposed to the carcinogen for a maximum of 320 days. In one group of animals, hypertrophia and hyperplasia affected the whole epithelium of the bladder. In the other group, hyperplasia was intense enough to be considered as carcinomatous. A third group developed papillomatous carcinomas, which occupied the whole interior of the bladder.

Animals↗

PubMedDate not supplied

Persistence of Borrelia burgdorferi and histopathological alterations in experimentally infected animals. A comparison with histopathological findings in human Lyme disease.

Gerbils appear to be susceptible to infection by human isolates of Borrelia burgdorferi; we obtained 100% infection. Isolation of the B. burgdorferi from different organs six months post infection causes a generalized infection thus demonstrating that borreliae persist in these animals for a long period. Spirochetemia was present for 14 days, apparently in two intervals. The Borrelia burgdorferi specific antibody titers increased with time after infection thus indicating the persistence of spirochetes. The intraperitoneal inoculation of the B. burgdorferi to six gerbils of groups A and B induced significant histopathologic changes in most of the major organ systems and their surrounding adipose and fibrous connective tissues. The infiltrates consisted mainly of lymphocytes and histiocytes. Various numbers of plasma cells, eosinophils and high numbers of mast cells were also present. Three further animals which served as controls displayed no histological signs of inflammation in any organ system. No significant differences were noted between the histopathological findings seen in the animals of groups A and B (infected with cells from subcultures no. 25 and with no. 5, respectively). The persistence of B. burgdorferi and the high number of organs involved with slight to severe signs of inflammation in this series can be compared to persistence and to the multiorgan involvement seen in human Lyme disease. Thus gerbils can serve as suitable experimental animals to study the pathogenesis of Lyme disease and the extent of organ damage caused by B. burgdorferi.

Animals↗

PubMedDate not supplied

Active immunization with pC protein of Borrelia burgdorferi protects gerbils against B. burgdorferi infection.

Serious infection due to Borrelia burgdorferi and the disseminated infection characteristic of the disease possess unique treatment problems. The wide and still increasing incidence of Lyme borreliosis as well as the problems in treatment call for effective prevention strategies by active immunization. Vaccination experiments were done to determine if active immunization of gerbils with recombinant OspA and pC protects against infection with strains of B. burgdorferi. Gerbils were vaccinated with recombinant OspA and pC (20 kDa protein) and challenged four weeks later with a clone (derived from B. burgdorferi strain PKo) which expresses an abundant amount of pC but only little OspA. Non-immunized gerbils challenged with the same B. burgdorferi strain were used as controls. Both groups of immunized gerbils developed antibodies against the recombinant vaccines. The pC vaccinated group was protected against infection, whereas the OspA vaccinated group showed signs of infection. The non-vaccinated group developed generalised infection. These results show that pC should be considered as a further vaccine candidate and probably needs to be combined with OspA for an efficient vaccine against B. burgdorferi.

Animals↗

PubMedDate not supplied

Strong association of interleukin-6 -174 G>C promoter polymorphism with increased risk of oral cancer.

In view of the recently found contribution of factors associated with thrombosis and inflammation to carcinogenesis, we investigated the possible association of interleukin-6 (IL-6) with an increased risk of oral cancer. In DNA samples of 162 patients with oral squamous cell carcinoma and 156 healthy controls of comparable ethnicity, age and sex, we studied the -174 G>C polymorphism in the IL-6 gene, which affects its transcription. C allele frequencies were significantly increased in patients compared to controls, 42.6% versus 23.1% (p<0.001). The CC homozygotes had a 7-fold greater risk of developing oral cancer (odds ratio 7.39, 95% CI 2.61-20.92), while the GC heterozygotes had a 4-fold greater risk (odds ratio 3.74, 95% CI 2.29-6.11). A significant increase in C alleles was observed in patients regardless of their smoking or alcohol consumption habits, early or advanced stage of cancer, and presence or absence of a family history for cancer or thrombophilia (p<0.001; Fisher's exact test). These findings suggest that the -174 G>C polymorphism, by affecting IL-6 gene expression, is strongly associated with oral oncogenesis.

Adult↗

PubMedDate not supplied

Tumor histology and stage but not p53, Her2-neu or cathepsin-D expression are independent prognostic factors in breast cancer patients.

BACKGROUND: Several factors are currently employed for prognosis assessment and treatment determination in breast cancer. An array of molecular parameters, such as p53, Her2-neu (c-erbB 2) and Cathepsin-D, are also examined to improve clinical patient management. We have conducted a statistically powerful study of the prognostic value of conventional factors and of the investigational factors p53, Her2-neu and Cathepsin-D in patients with invasive breast carcinoma, in order to compare their significance. Our analysis was extended to determine the associations of p53 and Her2-neu with risk of death and relapse among patients with and without lymph node metastases. MATERIALS AND METHODS: In a set of 125 primary breast tumors, p53 and Her2-neu expression were immunohistochemically evaluated. Cathepsin-D, estrogen and progesterone receptor concentrations were determined in cytosols by a standard immunoradiometric assay. RESULTS: Over a mean of 62 months, 49 patients (39%) had a relapse and 29 patients (23%) died. Overexpression of p53, Her2-neu and Cathepsin-D was observed in 31%, 46% and 88% of cases, respectively. Overall survival was associated with histology (hazard ratio 0.04, 95% confidence interval: 0.01, 0.49 for lobular tumors) and stage (hazard ratio 5.94, 95% confidence interval: 1.30, 27.15 for stage III samples). Disease-free survival was also related to histology (hazard ratio 0.23, 95% confidence interval: 0.08, 0.73 for lobular tumors) and stage (hazard ratio 4.27, 95% confidence interval: 1.36, 13.36 for stage III tumors). Patients with both negative nodal status and Her2-neu overexpression tended to display an elevated risk of death. CONCLUSION: Our results support the prognostic power of tumor histology and stage and emphasize the need for further studies on the prognostic impact of p53. Her2-neu and Cathepsin-D in breast cancer. Additionally, our analysis indicates that deregulation of Her2-neu might characterize a subgroup of node-negative patients with poor prognosis who could benefit from an aggressive adjuvant therapy.

Adult↗

PubMedDate not supplied

Microsatellite instability in sporadic and inherited colon adenocarcinomas from Greek patients: correlation with several clinicopathological characteristics.

BACKGROUND AND AIMS: Microsatellite instability seems to play a significant role in colorectal carcinogenesis, as it is reported to occur in HNPCC patients as well as in a proportion of sporadic cases. The aim of this study was to examine the presence of microsatellite instability in relation to other commonly observed genetic abnormalities and clinicopathological characteristics of sporadic and inherited colorectal cancers. METHODOLOGY: One hundred and three sporadic colorectal adenocarcinomas and 9 adenocarcinomas from HNPCC patients were histologically evaluated. The presence of microsatellite instability was investigated at six loci. K-ras and p53 mutations, p53 LOH, hMLH1 expression and methylation status were examined as well. Statistical analysis was performed to define possible correlations of the observed genetic alterations with the clinicopathological characteristics of the analysed tumors. RESULTS: High-grade microsatellite instability was found in 14% of sporadic adenocarcinomas and in 78% of adenocarcinomas from HNPCC patients. K-ras and p53 mutations were found in 29% and 28% of sporadic adenocarcinomas respectively and in 0% and 22% of the 9 HNPCC cases. A statistically significant correlation was noticed in sporadic tumors between the presence of MSI-H and tumor location at the proximal colon, as well as with the female gender. CONCLUSIONS: Sporadic MSI+ colon adenocarcinomas seem to represent a distinct entity with a unique profile of genetic changes, different from those observed in HNPCC or MSI negative sporadic tumors.

Adaptor Proteins, Signal Transducing↗

PubMedDate not supplied

Relationship between Ki-67 positive cells, growth rate and histological type of human intracranial tumors.

The proliferation rate of 40 intracranial neoplasms (30 gliomas, 1 hemangioblastoma, 3 meningiomas, 1 neurinoma and 5 brain metastases) was investigated using the monoclonal antibody Ki-67. In eleven of the gliomas recurrences could be observed, and two of them recurred for second time. In total the Ki-67 labelling indices of 53 specimens were investigated. The Ki-67 nuclear antigen was demonstrated in frozen sections by application of the appropriate monoclonal antibodies according to a modified alkaline phosphatase-antialkaline phosphatase (APAAP) technique. The proliferation rate was evaluated by cell count calculation of the staining index. Ki-67-labelled glioma cells varied from 0.2 percent in one meningioma (WHO-grade I) to 9.1 percent in one glioblastoma. In ten glioma recurrences, higher Ki-67 staining indices could be observed than in their primaries, even when the histological grading did not change substantially. In a cerebellar hemangioblastoma, a trigeminal neurinoma and two endotheliomatous meningiomas the fraction of stained nuclei was less than one percent; however, one recurrent transitional meningioma without any histological sign of malignancy showed a staining index of 2.4 percent. The staining indices of five brain metastases of different malignancies ranged from 1.5 percent in a malignant melanoma to 6.1 percent in bronchial carcinoma. In the majority of the cases examined, the percentage of Ki-67 labelled cells was in accordance with the histologic grade of the neoplasm. In general, there was a direct relationship between the number of stained nuclei and the frequency of mitoses (mitotic index) evaluated in hematoxylin-eosin stained frozen sections. Interestingly, the frequency of mitosis and stained nuclei were higher in tumor recurrences than in the primaries. The results of this study imply that immunohistological labelling of the proliferating cell fraction should become an important additional criterion to predict the biological behaviour of human nervous system neoplasms.

Adult↗

PubMedDate not supplied

Cellular composition and distribution of gliomesenchymal nodules in the CNS of AIDS patients.

The pathology of AIDS encephalopathy and its relation to other CNS infections in AIDS was studied in 112 autopsies of AIDS patients and 14 of HIV-positive patients. Special interest was focused on gliomesenchymal nodules (GMNs), a common finding in encephalitis of various etiologies, and on giant cells. GMNs and giant cells were found in 40 patients. These 40 were used for the present study, they were further divided into five groups: I. 21 with AIDS encephalopathy; II. 3 with HIV infection but no AIDS; III. 8 with Toxoplasma encephalitis; IV. 7 with cytomegalovirus encephalitis; and V. 1 with cryptococcus encephalitis. Comparison of the morphological features of GMNs between the five groups revealed parameters which may help distinguish GMNs in HIV infection from opportunistic infections. Small GMN size, low cellular density, ill-defined demarcation from the adjacent brain paraenchyma, minimal tissue rarefaction in the area of GMNs and a strong predilection for the superficial and deep white matter were typical of AIDS encephalopathy. In contrast, opportunistic infections were usually associated with clear demarcation from surrounding brain tissue, high cellular density, strong tissue rarefaction and a predilection for gray matter. Rod cells and macrophages in great numbers were also more commonly found in the AIDS and HIV groups.

AIDS Dementia Complex↗

PubMedDate not supplied

A study of apoptosis in brain tumors by in situ end-labeling method.

Recognition of apoptotic cells has recently been facilitated by in situ end-labeling (ISEL) techniques which identify DNA strand breaks. The ISEL assay has been applied in 26 brain tumors, meningiomas, and gliomas of different grade of malignancy in order to determine the apoptotic index (AI). Apoptotic cells were readily found in all the examined tumors; in most cases the AI values were below 1%. Any significant relationship between AI and grade of malignancy could not be determined. However, the AI mean value of the meningiomas was higher than that of gliomas WHO II and III, respectively. Furthermore, it seemed that in the examined gliomas, with the exception of the glioblastoma group, low grade malignancy was related with higher AI values. The latter decreased gradually in the WHO II and III group of tumors, respectively. Our preliminary results indicate that an apoptotic process may play a significant role in brain tumor kinetics and will probably contribute to our understanding of the biologic behavior of those tumors.

Apoptosis↗