Biomedical subjects

H Paraskevakou

Publications and source records attributed to H Paraskevakou.

18 recordsLinked to original sources

PubMed2001

Localization of the glucocorticoid receptor in rat brain mitochondria.

The distribution of glucocorticoid receptor in subcellular fractions of brain cortex and hippocampus, two regions rich in glucocorticoid receptor, has revealed its presence in nuclei, cytosol, mitochondria, synaptosomes, and synaptosomal mitochondria. The identification of glucocorticoid receptor has been accomplished both by Western blotting using antibodies recognizing the carboxy and the amino terminus of the glucocorticoid receptor and by immunogold electron microscopy using the same anti-glucocorticoid receptor antibodies. Antibody-glucocorticoid receptor interaction is abolished by preincubation of each antibody with its competing peptide. In addition to the intact 95-kDa glucocorticoid receptor in all fractions, lower molecular weight glucocorticoid receptor fragments have been also detected by Western blotting. The presence of glucocorticoid receptor in brain mitochondria supports the concept of a direct action of glucocorticoids on mitochondrial gene transcription, parallel to the established primary actions of the hormones on nuclear gene transcription, as a mechanism of coordinate regulation of respiratory enzyme biosynthesis by steroid hormones.

Animals↗

PubMed2000

Lectin histochemistry as a predictor of dysplasia grade in colorectal adenomas.

Lectins are sugar-binding proteins that bind to specific cellular carbohydrates, commonly affecting cellular physiology. Phaseolus vulgaris leucoagglutinin (PHA), ulex europaeus isoagglutinin-I (UEA-I), wheat germ agglutinin (WGA) and peanut agglutinin (PNA) are among the most well studied lectins in various tissues. The purpose of this study was to detect the above lectins binding sites and so examine alterations in glycoconjugate expression in neoplastic cells of 52 colorectal adenomas with various clinicopathologic characteristics and proliferation rates. Lectin histochemistry was performed in paraffin sections with and without neuraminidase treatment. Proliferative fraction was determined by immunolabelling for Proliferating Cell Nuclear Antigen. PHA was the more frequently positive lectin in the examined specimens; however, it was simultaneously detected in normal colonic mucosa and so was WGA. The frequency of high grade dysplasia was significantly greater in older patients and in samples with UEA-I positivity without neuraminidase pretreatment. UEA-I-reactive adenomas were generally characterized by high cell proliferation rates. A statistical model based on patients age and UEA-I binding without neuraminidase treatment can generally predict grade of dysplasia in 83% of adenomas and particularly high grade dysplasia in up to 93% of adenomas; so, such a model may be potentially useful for the early detection of neoplasia, for instance in exfoliative cells from the large intestine.

Age Factors↗

PubMed2000

Membranous glomerulonephritis: a morphometric study.

Archival material from 45 renal biopsies with a diagnosis of idiopathic membranous glomerulonephritis (MGN) were studied by computer-aided image analysis in order to evaluate the prognostic significance of glomerular and interstitial morphometry in MGN. The control group consisted of thirty seven normal renal biopsy specimens. The surface area, the perimeter, the major axis length and the shape factor of renal glomeruli as well as the percentage of the interstitial fibrosis were measured. All the morphometric parameters related to the size of glomeruli had significantly higher values in the patient group (p = 0.000 for all the parameters). However, no significant difference of the glomerular size between different stages of MGN was observed. In contrast, the percentage of interstitial fibrosis increased as the MGN stage rose (median values: 10.3% in stage 1, 14.2% in stage II, 26.9% in stage III, 28.9% in stage IV and 34.2% in stage V, Kruskal-Wallis ANOVA H = 37.645, p = 0.000). In the multivariate analysis the percentage of interstitial fibrosis was the only independent prognostic factor (p = 0.013). Our findings suggest that, in membraneous glomerulonephritis, the interstitial fibrosis increases as the MGN stage progresses, while the size of renal glomeruli has increased at a very early stage of the disease. This fact may indicate that interstitial fibrosis, not glomerular lesions, is mainly responsible for the reduction of renal function.

Adult↗

PubMed2000

Spontaneous interbody fusion after controlled injuries to the spine: an experimental study in rabbits.

To evaluate the rationale of spontaneous spine fusion after a spinal injury, the authors conducted an experimental study that consisted of three types of controlled injuries to a rabbit spine model. The first was injury to the intervertebral disk (type I injury). The second was injury of the intervertebral disk along with injury to one of the adjacent vertebral end plates (type II). In type III injury, both the opposing end plates were injured along with the intervertebral disk. In 38 rabbits, a total of 82 injuries of these three types were inflicted. Twenty-six injuries were of type I (n = 22 rabbits), 26 were type II (n = 24 rabbits), and 30 were type III (n = 26 rabbits). Spontaneous fusion occurred only in type III injuries. From the 30 type III injuries, fusion occurred in 20 (66.6%). For an autofusion to occur, both epiphyseal plates may be injured. In the clinical situation, this observation suggests that a radiographically obscure lesion of both neighboring vertebrae may proceed to autofusion of that spinal segment observed later.

Animals↗

PubMed2000

Computerized morphometric study on fine needle aspirates of cellular follicular lesions of the thyroid.

OBJECTIVE: To investigate the value of computerized nuclear morphometry in the differential diagnosis of cellular follicular lesions of the thyroid cytologically diagnosed on fine needle aspiration (FNA) smears. STUDY DESIGN: Sixty cases of FNA thyroid smears were cytologically diagnosed and classified as follows: 30 cases of follicular carcinoma, 20 cases of cellular hyperplastic nodules and 10 cases of follicular adenoma. Using an image analysis system, two morphometric variables, nuclear area and major axis length of the nucleus, were measured for each case. RESULTS: For both nuclear morphometric variables, statistical differences were found between carcinomas and hyperplastic nodules as well as between carcinomas and adenomas. No statistical differences were found between the nuclear variables in either hyperplastic nodules or adenomas. CONCLUSION: The results confirm the aim of our study, to establish nuclear morphometry by computerized image analysis as an additional tool in the differential diagnosis of thyroid follicular lesions cytologically diagnosed on FNA smears.

Adenocarcinoma, Follicular↗

PubMed1999

Morphological-histochemical study of intestinal carcinoids and K-ras mutation analysis in appendiceal carcinoids.

Intestinal carcinoids are potentially malignant neoplasms. Their histogenesis and pathogenesis are currently uncertain. The morphological and histochemical characteristics of twenty intestinal carcinoids are studied. The primary sites of three mucin-producing tumors were examined by electron microscope. Furthermore 11 appendiceal carcinoids were analysed by the polymerase chain reaction (PCR) for the detection of ras and p53 point mutations. Microscopically all carcinoids were of mixed type. Focal mucin production was evident in three carcinoids that metastasised to regional lymph nodes. HID-Alcian blue staining proved that mucin in both primary and secondary foci did not belong to the sulphated group. The secretory granules and mucin droplets found in a single neoplastic cell suggest that carcinoids of the small intestine and some of the appendix arise from the endoderm. Neither ras nor p53 mutations were detected. It seems that ras oncogenes are probably not involved in the pathogenesis of appendiceal carcinoids.

Adolescent↗

PubMed1999

A solitary cutaneous tumor with distinct areas of verruca and seborrheic keratosis-like lesion.

A single, exophytic, cutaneous tumor on the thigh of a 52-year-old man was examined by light microscopy, in situ hybridization and immunohistochemistry. It demonstrated distinct areas of verruca and of seborrheic keratosis-like morphology simultaneously. Focally, architectural abnormalities were noted in some deeper parts of the tumor, but there was no morphological evidence of malignancy. The patient has remained disease-free for two and a half years after surgery. Biotinylated full genomicDNA probes of HPV confirmed the presence of types 6/11 exclusively in the verrucous portion of the neoplasm. In the verrucous component p53 protein was overexpressed and, additionally, increased Ki-67 immunopositive signals were detected, being localized below the HPV-DNA-expressing spinous cells.

DNA, Viral↗

PubMed1999

Middle ear adenomatous tumor with a predominant neuroendocrine component.

A primary adenomatous tumor of the middle ear was examined by light microscopy, ultrastructural and immunohistochemical techniques. In support of its extensive neuroendocrine differentiation, was the diffuse detection of neuron-specific enolase (NSE) and positive immunoreaction with antibodies to chromogranin and synaptophysin. The great majority of tumor cells contained neurosecretory granules and intraluminal mucin production could be focally detected. These characteristics confirm the diagnosis of a middle ear adenomatous tumor (MEAT) of a biphasic nature and with a prominent neuroendocrine component.

Adenoma↗

PubMed1999

In situ expression of E-selectin and intercellular adhesion molecule-1 in chronic inflammatory diseases of the gastrointestinal tract.

AIM: The study of cell adhesion molecules contributes to our understanding of the inflammatory mechanisms which include the endothelial activation of newly formed or pre-existing vessels, the increase of inflammatory cells' adhesive capability and their migration into perivascular tissues. The aim of the present study was to investigate the local presence and the extent of expression of E-selectin and intercellular adhesion molecule-1 (ICAM-1) in the mucosa of patients with chronic gastritis, chronic inflammatory bowel disease, and controls, as well as to identify possible correlations between in situ expression of the above adhesion molecules and degree of inflammatory activity or therapeutic response. DESIGN: In cryostat tissue sections we examined the immunohistochemical expression and localization of E-selectin and the intercellular adhesion molecule-1 (ICAM-1). Our specimens consisted of 27 cases of chronic gastritis, 42 cases of ulcerative colitis, and 15 cases of Crohn's disease. RESULTS: E-selectin was expressed in capillary endothelia as well as on neutrophils, located either in the lamina propria or in the glandular epithelia or lumina. This marker's expression was associated with the active phase of ulcerative colitis (p<0.0005) and possibly of chronic gastritis (p=0.06). ICAM-1 immunolabelling was localized in endothelia and chronic inflammatory components which had passed through the vascular walls. This marker's immunoreactivity was generally increased in all our specimens compared to normal mucosa and generally tended to correlate with chronic phases of the inflammatory process (p<0.10). CONCLUSIONS: E-selectin regulates the accumulation of neutrophils in the early stages of the inflammatory process and is thus associated at least with the active phase of ulcerative colitis. Whether any post-therapy alteration of E-selectin immunopositivity seems to indicate a good response to drug therapy is well worth investigating in ulcerative colitis patients. ICAM-1 immunoreactivity in lymphoplasmacytic infiltrates might serve as a marker of chronic immune stimulation, which is potentially responsible for the persistence of the inflammatory disorders.

Adolescent↗

PubMed1998

Lipoid proteinosis of the oral mucosa: case report and review of the literature.

We describe a 37-year-old woman who presented with progressive mouth dryness. Physical examination revealed long-standing plaques on the face and upper limbs, papular lesions of the oral cavity and tongue firmness. A lower lip biopsy was performed. Light microscopy demonstrated accumulation of PAS-positive material around blood vessels, capillaries and salivary gland canaliculi as well as focally massive hyaline deposits in the submucosa. Immunohistochemistry revealed widespread presence of type IV collagen in the hyaline material and around thickened blood vessels. Laminin immunoreactivity was particularly strong at thickened basement membranes. The above findings were compatible with lipoid proteinosis, which is likely to involve primary perturbation of collagen metabolism and production of glycoproteins.

Adult↗

PubMed1998

Neuroendocrine differentiation in follicle-cell thyroid carcinoma: correlation to prognostic factors in papillary carcinoma.

The presence of NE-differentiation in the follicle-cell thyroid carcinoma has been investigated by immunohistochemical detection of chromogranin A in the neoplastic cells. It has been found that NE-differentiation was present in a significant percentage in the papillary Ca alone (46.60%) whereas all Huerthle-cell neoplasms and the large majority of follicular and undifferentiated carcinomas showed non reactivity for Chromogranin A. Moreover, we have correlated the presence of NE-differentiation to well known prognostic factors in papillary Ca. We found a statistically significant correlation between the neuroendocrine differentiation and some unfavourable factors such as old age of the patient, size of the tumor, invasion of thyroid capsule and lymphnode involvement. We suggested that NE-differentiation could be considered as an index of poor prognosis.

Adenocarcinoma, Follicular↗

PubMed1997

Findings of computerized nuclear morphometry of papillary thyroid carcinoma in correlation with the age of the patients.

The aim of this study was to evaluate the usefulness of nuclear morphometry in the pathology of papillary thyroid carcinoma by computer-aided image analysis and the statistical comparison of nuclear morphometric parameters with the age of patients. Seventy cases of papillary thyroid carcinoma diagnosed by fine needle aspiration (FNA) biopsies were classified into two groups according to the patients' age (group I: <45 years and group II: >45 years). The following six nuclear morphometric parameters were measured in a large number of randomly selected nuclei of each case: area, perimeter, major axis length, elongation, roundness, and compactness. The statistical analysis was performed by using special algorithms, and the results of the two groups were compared for each of the parameters measured using the t-test. Area, perimeter, and major axis length of papillary thyroid carcinoma nuclei demonstrate a statistically significant correlation with the age of patients, whereas elongation, roundness, and compactness did not show any correlation. Nuclear morphometry in association with the follow-up of patients could be suggested as an important prognostic index for papillary thyroid carcinoma.

Adolescent↗

PubMed1989

[Loss of beta 2 microglobulin from the surface of "dysplastic" and malignant epithelial cells of the uterine cervix].

We studied 75 cervical biopsies (39 cases with CIN I-III and 36 with invasive squamous carcinoma differentiated to various degrees) immunohistochemically to determine the beta 2-m content of the epithelial cells. In cells having CIN we found a clear decrease in beta 2-m with a statistically significant correlation to the degrees of severity of the lesion. All of the invasive carcinomas showed a complete absence of beta 2-m. This finding should be evaluated within the framework of an immunological dedifferentiation, and it supports the views regarding the neoplastic nature of cervical dysplasia. The demonstration of beta 2-m in atypical epithelial cells of the cervix is a possible indication for the intraepithelial localisation of the lesion.

Biopsy↗

PubMed1988

Primary myxoid chondrosarcoma of the thyroid gland.

We describe a case of primary myxoid chondrosarcoma of the thyroid gland that occurred in a 68-year-old man. To our knowledge, this is the first case of such a tumor reported in the english literature under this name.

Aged↗

PubMed1985

Unilateral ureteric ligation in diabetic rats: a pathologic and morphometric study.

We studied the combined effect of unilateral ureteral ligation on the morphology and pathology of the contralateral kidney in normal and streptozotocin induced diabetic rats. In the diabetic group that underwent ligation of the right ureter the weight and volume of the left kidney was far greater, the tissue specific gravity far lower, while the percentage of affected glomeruli was significantly greater compared with control rats and those undergoing only ureteric ligation.

Animals↗

PubMed1983

Prognosis after immunosuppression of patients with crescentic nephritis requiring dialysis.

48 patients with rapidly progressive glomerulonephritis were treated by a regimen of intensive plasma exchange, steroids, and cytotoxic drugs. All required dialysis before immunosuppressive treatment was started, and all had 50% or more of their glomeruli affected by crescent formation. Renal function was not recovered in any of the 21 patients with anti-glomerular basement membrane antibody disease. In contrast 63% of patients without these autoantibodies recovered renal function. Plasma creatinine remained stable over prolonged follow-up (6-60 months) in all but 1 of the 10 late survivors. There was no correlation between the extent of crescent formation and recovery of renal function in those patients without circulating anti-glomerular basement membrane antibodies.

Adolescent↗

PubMed1983

Effect of dietary protein restriction on the development of renal failure after subtotal nephrectomy in rats.

We have examined the effect of a low protein diet on the development of glomerular sclerosis and progressive renal failure after subtotal nephrectomies in rats. Two groups of male Sprague-Dawley rats were studied after five-sixths nephrectomy; group 1 were maintained on a normal diet (13.5 g day-1 kg-1 body weight) and group 2 were fed with a low protein diet (6 g day-1 kg-1 body weight). Rats maintained on a low protein diet survived for longer, and had significantly less glomerular sclerosis and significantly greater glomerular filtration rates when the experiment ended after 7 months. We conclude that dietary protein influences favourably the development of glomerular scarring and renal failure after subtotal nephrectomy in rats.

Animals↗

PubMedDate not supplied

Histological diagnosis of cutaneous "warty" carcinoma on a pre-existing HPV lesion.

A middle-aged man with an 8-year history of a fungating tumour mass on his thigh was histologically diagnosed as having an invasive "warty" carcinoma at the location of a pre-existing human papillomavirus (HPV) lesion. The tumour surface had a verruciform appearance with papillae containing fibrovascular cores. Many of the malignant cells displayed changes consistent with koilocytotic atypia. We noticed a greater degree of nuclear atypia in comparison with a verrucous carcinoma. Focally, some neoplastic cells demonstrated features of basaloid differentiation. Under in situ hybridization conditions, only HPV16 DNA, which is commonly associated with genital neoplasia, was detected selectively in rather superficial areas, corresponding to morphological evidence of HPV infection (i.e. koilocytotic atypia). It is worth noting that cutaneous location of such a warty carcinoma is very rare.

Carcinoma, Verrucous↗