Biomedical subjects

G Akyol

Publications and source records attributed to G Akyol.

26 records · Page 2Linked to original sources

PubMed1995

Overexpression of p53 in laryngeal carcinoma: clinicopathological implications.

The aims of this study were to determine the incidence of p53 overexpression in squamous cell carcinoma of the larynx and to establish whether or not this bore any relationship to survival, location, stage, histological differentiation, nuclear atypia, mitotic activity, stromal desmoplasia, tumor-associated tissue eosinophilia, or stromal lymphoplasmocytic infiltration. Paraffin blocks from 51 cases of laryngeal squamous cell carcinoma with a minimum follow-up period of 36 months were recut and stained immunohistologically with anti-p53 antibody using the streptavidin-biotin technique. Results were compared with clinicopathological features with Kruskal-Wallis and Mann-Whitney tests. Sixty-three percent of tumors showed positive staining for p53, and in addition, 15% of the sections with adjacent normal or dysplastic mucosa showed positive staining. No relationship between p53 staining and prognosis or any other one of the aforementioned clinicopathological parameters was observed. Although p53 overexpression is a common feature in laryngeal carcinomas, it does not seem to have an impact on prognosis and it does not bear any relationship to the aforementioned clinicopathological parameters.

Carcinoma, Squamous Cell↗

PubMed1992

Detection of replicative hepatitis C virus sequences in hepatocellular carcinoma.

Several serologic studies suggest that infection by hepatitis C virus (HCV) may be associated with the development of hepatocellular carcinoma (HCC). Therefore, we examined tumor tissue and/or the surrounding liver of 20 patients for viral sequences by the polymerase chain reaction (PCR). In 12 cases, liver and tumor tissues were separable for extraction. RNA was extracted from frozen tissues and used as a template for reverse transcription followed by double PCR with nested primers for the 5'-untranslated (NT) and nonstructural NS3 regions of HCV. In addition, the tissue extracts were tested by single PCR for X gene and S gene sequences of hepatitis B virus (HBV). NT region sequences of HCV were detected in the available tumor tissue of all anti-HCV-positive patients except for one. Negative (replicative) strands of HCV RNA were found in the same tissues as positive (genomic) strands at almost the same relative amounts, suggesting replication of HCV in the tumor tissue rather than contamination by HCV-positive blood. HBV X and S sequences were demonstrated in two tumors, but were absent from three tumors that were surrounded by liver tissues with HBV X sequences. One patient had nucleic acids of both viruses in tumor tissue. These observations suggest that in addition to HBV, HCV may play a role in the development of hepatocellular carcinoma.

Adolescent↗

PubMed1992

Detection of hepatitis C virus RNA sequences by polymerase chain reaction in fixed liver tissue.

Currently, the most reliable method for the diagnosis of hepatitis C virus (HCV) infection is the detection of viral sequences by the reverse transcription double polymerase chain reaction (RT/PCR) in serum or liver samples. We demonstrate here that noncoding region sequences (NT) of HCV were amplifiable by RT/PCR in guanidinium extracts of formalin-fixed (for 6 to 48 h), paraffin-embedded liver sections of patients with chronic hepatitis C. In contrast, core and nonstructural region sequences of HCV were not detectable in fixed tissues by PCR amplification. Boiling of routinely processed tissue sections in water containing Chelex-100, a method for extraction of amplifiable hepatitis B virus DNA, was not successful. The amount of nucleic acid extracts from fixed liver sections needed for amplification of NT region sequences was over 1000 times larger than that of extracts from frozen tissue. This method will be useful for diagnostic and investigative studies of HCV infection.

Aged↗

PubMedDate not supplied

Bcl-2 and LMP1 expression in nasopharyngeal carcinomas.

In vitro studies of B-cells immortalized by Epstein-Barr Virus (EBV) have shown that B-cell leukemia/lymphoma-2 (bcl-2) protein expression is upregulated by the EBV-latency-associated antigen, latent membrane protein 1 (LMP1). The same phenomenon has also been observed in epithelial cells in vitro. However, such correlation between these 2 markers has not been shown in nasopharyngeal carcinoma (NPC), in which EBV infection is a well-known etiologic factor. This retrospective study examined 35 cases of undifferentiated NPC to answer the question of whether LMP1 and/or bcl-2 presence can be used as biomarkers at treatment response, as well as to see the relationship between bcl-2 and LMP in NPC. Of the 35 patients, 26 (74.3%) were bcl-2, and 10 (28.6%) were LMP1-positive. Although a significant correlation was observed between bcl-2 and LMP1 staining (P =.003), it appeared that bcl-2 expression could be independent of LMP1. Statistical analysis showed that cervical lymph node metastasis (P =.04) and cranial nerve involvement (P =.03) are the only variables that significantly affect patient survival. At this time, bcl-2 and LMP1 presence are not significant indicators of outcome; however, although they are not directly related to survival, expression of both bcl-2 and LMP1 was strongly correlated with cervical lymph node metastasis, which is a potent predictor of patient survival.

Adaptor Proteins, Signal Transducing↗

PubMedDate not supplied

Proliferating cell nuclear antigen immunoreactivity and the presence of P53 mutation in basaloid squamous cell carcinoma of the larynx.

Basaloid squamous cell carcinoma (BSCC) is an aggressive variant of squamous cell carcinoma (SCC) that was first described in 1986. In the English literature, only 28 cases of this histopathological entity have been reported in the larynx. Proliferative features of this infrequent tumor were investigated by proliferating cell nuclear antigen immunoreactivity, and the presence of P53 mutation was also investigated in a series of 4 cases. BSCC was found to share similar features with regular SCC in terms of its proliferation rate and P53 mutation positivity, as well as biological behavior and clinical outcome.

Carcinoma, Basosquamous↗

PubMedDate not supplied

Effects of topical vitamin E on keratocyte apoptosis after traditional photorefractive keratectomy.

PURPOSE: To evaluate the keratocyte apoptosis and effects of topical vitamin E on keratocyte apoptosis after photorefractive surgery. METHODS: Rabbits were divided into 7 groups, and all groups were compared with controls after epithelial scraping, epithelial scrape and photorefractive keratectomy (PRK) (traditional PRK), transepithelial PRK, production of a corneal flap with microkeratome and laser-assisted in situ keratomileusis (LASIK). The effects of topical Vitamin E treatment were investigated in the traditional PRK group. The terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labelling assay (to detect DNA fragmentation in situ) and light microscopy have been used to detect apoptosis in rabbit cornea. RESULTS: Transepithelial PRK induced minimal keratocyte apoptosis, less than in all other refractive surgical procedures. The greatest amount of keratocyte apoptosis was observed after traditional PRK (p = 0.001), therefore we tested the effects of topical vitamin E in this group. The number of apoptotic keratocytes significantly reduced after vitamin E therapy (p < 0.005). CONCLUSION: Keratocytes undergo apoptosis after refractive surgery in response to mechanical epithelial removal, preparing of corneal flap and excimer laser stromal photoablation. The topical application of vitamin E immediately after surgery can prevent keratocyte apoptosis, and this result suggests that free radicals may be partly responsible for keratocyte apoptosis after excimer laser keratectomy.

Administration, Topical↗

PubMedDate not supplied

The protective effect of Ginkgo biloba extract on CCl4-induced hepatic damage.

The aim of this study was to evaluate the protective effect of Ginkgo biloba extract on CCl4-induced hepatic damage in rats. Hepatic malondialdehyde, glutathione and hydroxyproline levels and histopathologic alterations in liver specimens were assessed. 200 mg/kg/day Ginkgo biloba extract were given orally to the animals for 10 days, then a single dose of 2 ml/kg b.w. carbon tetrachloride was, administered intraperitoneally. Ginkgo biloba extract treatment reduced hepatic malondialdehyde levels significantly (p < 0.05), but did not alter glutathione (p > 0.05) and hydroxyproline levels (p > 0.05). The light and electron microscopic findings showed that Ginkgo biloba extract limited the CCl4-induced hepatocyte necrosis and atrophy. These results suggest that this extract may protect the hepatocytes from carbon tetrachloride-induced liver injury.

Animals↗

PubMedDate not supplied

Immunohistochemical localization of the epidermal growth factor receptor in normal mouse tissues.

The levels of epidermal growth factor (EGF) receptors were investigated in normal mouse tissues. Two patterns of reactivity were recognized: strong membraneous of diffuse cytoplasmic staining. The basal epithelial cells of the skin and the collecting tubule cells of the kidney showed membraneous reactivity whereas the bronchial epithelial cells, parietal cells of the stomach and tubular cells of the kidney showed cytoplasmic reactivity predominantly with the antibody. The distribution of the epidermal growth factor receptors in different cell types and cellular compartments may implicate varying activation states of the growth factor and its interaction with a milieu available ligand.

Animals↗