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Biomedical subjects

M Poljak

Publications and source records attributed to M Poljak.

At least 55 records · Page 3Linked to original sources
PubMed1997

Langerhans cells in human papillomaviruses types 6/11 associated laryngeal papillomas.

Some studies have shown a reduced density of Langerhans cells (LCs) within epithelium infected by human papillomaviruses (HPV) types 16/18. However, data on a correlation between HPV types 6/11 infection and LCs have been missing. To solve this problem, we analysed 24 biopsy specimens of laryngeal papillomas, selected randomly, 20 multiple and 4 solitary. The presence of HPV 6 and 11 was proven by polymerase chain reaction (PCR) using 2 different sets of primers in 23 biopsy specimens. Abnormalities of the covering stratified squamous epithelium were graded according to the Kambic-Gale classification. LCs were immunohistochemically labelled with 2 different antibodies, CD1a and S100. Quantitative analysis was performed to determine the density of LC per mm2 in different grades of epithelial abnormalities covering laryngeal papillomas. Although no statistically significant differences in the mean number of LCs per mm2 of the cross-sectioned epithelium covering laryngeal papillomas were observed comparing simple, abnormal and atypical hyperplasia groups, the mean number of LCs per mm2 in laryngeal papillomas associated with HPV types 6/11 infection substantially exceeded that of the vocal cord surface epithelium in patients with chronic laryngitis.

Adolescent↗
PubMed1997

Epidermal growth factor receptor, c-erbB-2 and p53 overexpressions in epithelial hyperplastic lesions of the larynx.

An immunohistochemical analysis of overexpression of epidermal growth factor receptor (EGFR), c-erbB-2, and p53 proteins was performed on 43 biopsies of laryngeal epithelial hyperplastic lesions (EHLL), classified according to the Kambic-Lenart classification, and in 11 cases of laryngeal carcinoma (SCCL). The aim of the present study was to determine whether there is a correlation between the staining patterns of these proteins and different grades of EHLL, and to reveal their possible prognostic value. We compared the staining patterns of atypical hyperplasia adjacent to cancer with the same type of lesions which have not turned malignant. p53 and EGFR overexpressions were detected in 28/54 (52%) and 33/54 cases (61%), respectively, and tend to increase with the degree of epithelial changes. The intensity of staining in various grades of EHLL adjacent to cancer was more pronounced than the same type of lesions which have not progressed to cancer. c-erbB-2 was weakly positive in the majority of cases, and changed from predominantly membranous in simple hyperplasia to cytoplasmic staining in abnormal and atypical hyperplasias. There was no significant statistic correlation between the amount of positive cells for all proteins and the grade of epithelial abnormalities. We conclude that the overexpression of each biomarker itself adds little predictive value over routine histomorphology, and cannot be regarded as a reliable prognostic factor for EHLL. However, the histologic characteristics of atypical hyperplasia together with the immunostaining patterns of EGFR and p53 up to two-thirds or more of the epithelial thickness could be considered a reliable pattern which correlates with the progression to cancer.

Carcinoma, Squamous Cell↗
PubMed1997

Sudden death caused by laryngeal papillomatosis.

Laryngeal papillomatosis (LP) is the most frequent benign neoplasm of the larynx. Clinically it causes hoarseness and upper airway obstruction. Though the LP has the potential to endanger life by asphyxiation, this unfortunate outcome is extremely rare. We report the case of a 19-year-old female who suddenly died of asphyxiation caused by massive LP.

Adult↗
PubMed1997

Human papillomavirus infection and expression of p53 and c-erbB-2 protein in laryngeal papillomas.

Laryngeal papilloma (LP) is the most frequent benign laryngeal epithelial tumor caused by human papillomaviruses (HPV) types 6 and 11. In the present study, we were interested in whether we can find any prognostic markers which might reflect the biological behavior of the covering epithelium in LP. We focused our attention on the determination of HPV infection, the detection of p53 protein, and c-erbB-2 protein in 24 biopsy specimens of LP. We confirmed the HPV 6 and 11 etiology in 23 of 24 LP. In these lesions the overexpression of p53 protein increased with the grade of epithelial abnormalities. The distribution of positive cells changed from scattered and focal, in simple and abnormal hyperplasia, to diffuse in atypical hyperplasia. It has been shown that in the presence of HPV types 6 and 11 found in LP, p53 can still preserve its tumor suppressor activity. Infection with HPV types 6 and 11 might therefore account for the significantly lower rate of malignant transformation in LP. Two staining patterns for c-erbB-2 protein were observed in the hyperplastic epithelium covering LP: membranous and cytoplasmic. With the increasing grade of epithelial abnormalities, cytoplasmic staining became predominant, and c-erbB-2 positivity sometimes occupied the whole epithelial thickness. This may represent either an alteration in the processing stability of the c-erbB-2 mRNA, gene amplification, or even an artefact.

Epithelium↗
PubMed1997

Distribution of hepatitis C virus genotypes in Slovenia.

To determine the prevalence of HCV genotypes in Slovenia, 203 subjects infected with hepatitis C virus (HCV) were studied using the Inno-Lipa HCV II assay (Innogenetics, Belgium). Of 21 patients infected by blood transfusion 19% had HCV subtype 1a, 81% had subtype 1b, and none of them was infected with genotype 3. In chronic hepatitis C patients infected by unknown cause subtype 1b was the most prevalent (54.4%), followed by subtype 1a (24.6%), genotype 3 (15.8%) and genotype 2 (5.2%). Genotype 3 (45.9%) and subtype 1a (43.2%) predominated among 74 intravenous drug users. In 37 haemodialysis patients genotypes 1 and 2 were almost equally frequent (40.5% and 37.8%, respectively), followed by genotype 3 (21.6%). Significant differences in HCV genotype distribution among distinct epidemiological groups observed in Slovenia indicate a close relationship between certain HCV genotypes and particular routes of viral transmission.

Chi-Square Distribution↗
PubMed1997

Particle agglutination test "Serodia HIV-1/2" as a novel anti-HIV-1/2 screening test: comparative study on 3311 serum samples.

Enzyme immunoassays are most widely used screening tests for antibodies to human immunodeficiency viruses (HIV). Nevertheless, the need of simpler, noninstrumented tests is evident in many parts of the world, where laboratory facilities and trained personnel are limited, and HIV incidence is high. A recently developed variant of gelatin-particle agglutination tests, Serodia HIV-1/2 (Fujirebio Inc., Tokyo, Japan), is one of such simple and noninstrumented tests. To evaluate its utility, 3311 serum samples (281 anti-HIV-1 positive, 8 anti-HIV-2 positive and 3022 anti-HIV-1/2 negative) obtained from 2632 individuals from Slovenia, other parts of former Yugoslavia and Senegal were investigated. No false-negative results and only one false-positive result were obtained during the procedures, giving overall sensitivity and specificity of the particle agglutination test of 100% and 99.97%, respectively. We have concluded that Serodia HIV-1/2 test is highly specific and sensitive for detection of anti-HIV-1/2 antibodies, suitable for small blood banks and for epidemiological surveys.

AIDS Serodiagnosis↗
PubMed1997

Comparative evaluation of four genotyping methods for hepatitis C virus.

Four most widely accepted genotyping methods for hepatitis C virus (HCV) were applied to 40 HCV RNA isolates obtained from Slovenian patients in order to determine the concordance and applicability of various genotyping systems. The four methods are: (i) amplification of the core region with genotype-specific primers; (ii) nested polymerase chain reaction (PCR) in the core region followed by hybridization to HCV type-specific probes; (iii) reverse hybridization with the line probe assay Inno LiPA (Innogenetics, Gent, Belgium) using type-specific probes for the 5' non-coding region (NCR); and (iv) restriction fragment length polymorphism analysis of DNA amplified from the 5' NCR. Additionally, in isolates with discordant results nucleotide sequence analysis of a part of the NS-5 region was performed. Both genotyping methods based on the analysis of the 5' NCR were found more sensitive than those methods based on the analysis of the HCV core region. None of the four genotyping methods correctly classified all Slovenian HCV RNA isolates. PCR with genotype-specific primers was identified as entirely unsuitable for genotyping of Slovenian HCV RNA isolates. The remaining genotyping methods could clearly differentiate between HCV genotypes, but were not entirely reliable for HCV subtyping. The specificity of genotyping methods, which are based on the 5' NCR or the core region, was occasionally hampered, due to a lack or excess of sequence variation in their respective target regions.

Genotype↗
PubMed1996

Rapid detection and typing of human papillomaviruses by consensus polymerase chain reaction and enzyme-linked immunosorbent assay.

A novel method for the detection and typing of human papillomaviruses (HPV) based on consensus polymerase chain reaction (PCR) using MY09/MY11 primers followed by detection of PCR products in a standard microtiter plate format using a recently developed commercially available standardised PCR ELISA kit (Boehringer Mannheim, Germany) was developed. The reliability and feasibility of the method were evaluated on 140 HPV-positive and 85 HPV-negative DNA samples extracted from different archival clinical specimens. Virtually complete agreement between the results of this novel method and the results of previous in-house PCRs and typing method was obtained. The sensitivity level of the novel method, determined by serial log-dilutions of SiHa cells, is about 50 copies of HPV 16. The PCR-ELISA provides the potential for an automated, simple, rapid and accurate test for detection and typing of HPV in diagnostic virological laboratories.

Base Sequence↗
PubMed1996

p53 protein expression in esophageal squamous cell papillomas: a study of 36 lesions.

BACKGROUND AND METHODS: In the present study 36 esophageal squamous cell papillomas (ESCP), uncommon benign neoplasms of the esophagus, were investigated retrospectively for p53 immunoreactivity by using the monoclonal antibody PAb 1801. Two ESCPs had previously been found to be human papillomavirus (HPV) type-6-positive. RESULTS: Only very occasional epithelial cells were stained in two cases, and in three ESCPs p53 staining was restricted to the basal epithelial cells. Both HPV-positive ESCPs remained p53-negative. CONCLUSION: We speculate that these findings are the result of immunohistochemical detection of the stabilized wild-type p53 protein rather then mutated p53 protein.

Adult↗
PubMed1996

Association of risk factors for cervical cancer and human papilloma viruses in invasive cervical cancer.

Our study was carried out on 70 patients with invasive squamous carcinoma of the uterine cervix (CC) or invasive adenocarcinoma of the uterine cervix at all stages, admitted to the University Department of Gynecology and/or to the Institute of Oncology in Ljubljana. The patients were not selected by age. A questionnaire on known risk factors in CC was filled in for each of the 70 patients, and two tumor smears were taken for the determination of human papilloma viruses (HPV) 16 and 18 by means of in situ hybridization and polymerase chain reaction (PCR). Each patient also had the serum level of vitamin A determined. The results of our study revealed a correlation between HPV 16 or 18 infection (60:40) and CC. When analysing some already known risk factors, no statistically significant difference could be established for any of the factors studied, except for the age at first birth.

Adenocarcinoma↗
PubMed1995

Use of a commercial PCR kit for detection of hepatitis C virus.

To evaluate the usefulness of a recently developed standardised reverse transcription polymerase chain reaction (PCR) kit for detection of hepatitis C virus RNA (Amplicor HCV Test, Roche Molecular Systems), a total of 322 serum samples were examined and compared to an in-house nested PCR. Seventy-nine samples were found positive and 237 samples negative by both methods. Five sera were reactive by the commercial test only, and one was reactive by the nested PCR only. It was concluded that the commercial HCV test had comparable sensitivity and specificity to the in-house nested PCR. However, the commercial HCV test was more rapid and easier to perform than nested PCR and is thus more appropriate for use in a diagnostic microbiology laboratory.

Base Sequence↗
PubMed1995

Laboratory acquired tick-borne meningoencephalitis: characterisation of virus strains.

BACKGROUND: The handling of tick-borne encephalitis (TBE) virus is potentially hazardous, as indicated by a number of laboratory-acquired infections in the prevaccination era. OBJECTIVES: (1) To reemphasize the hazard of handling TBE virus without being vaccinated by describing the case of a laboratory-acquired full-blown TBE in a microbiologist who isolated the virus from a blood sample. (2) To molecularly characterize the causative virus strain isolated in Slovenia in comparison with the European prototype strain Neudoerfl. STUDY DESIGN: The virological diagnosis of the laboratory infection was established by serology and virus isolation. The virus was characterized by restriction fragment analysis of PCR products of amplified genomic sequences and a panel of monoclonal antibodies reacting with the major envelope protein. RESULTS: The laboratory infection, most probably acquired by aerosol, resulted in a biphasic course of the disease with a severe meningoencephalitis in the second phase. Both by restriction fragment and monoclonal antibody analysis the Slovenian virus strains involved were indistinguishable from the European prototype strain. CONCLUSIONS: This report confirms the potential hazard of handling TBE virus in the laboratory without being vaccinated. The similarity of the virus isolates from Slovenia with the European prototype strain confirms the previously observed homogeneity of TBE virus strains from different European countries.

Journal Article↗
PubMed1995

Isolation of DNA from archival Papanicolaou stained cytological smears using a simple salting-out procedure.

DNA from archival Papanicolaou stained and unstained cytological smears was successfully isolated using a simple, rapid and inexpensive salting-out procedure. The quality of DNA was controlled by polymerase chain reaction (PCR) amplification of segments of the human beta-globin, human beta-actin and human papillomavirus L1 genes. Only negligible differences in amplification efficiency were observed between DNA isolated from stained and unstained smears. The salting-out procedure is a more rapid method for the isolation of DNA than phenol-chloroform extraction and may be used in instances where fresh or cryopreserved clinical specimens are not available.

Journal Article↗
PubMed1994

Laryngeal papillomatosis: molecular, histopathological, and clinical evaluation.

Molecular, histopathological, and clinical studies were carried out on a series of 79 laryngeal papillomas (LP) from 36 patients in order to investigate the hypothesis that juvenile and adult LP may represent a biological entity causally related to Human papilloma virus (HPV) infection. Using in situ hybridization with biotin-labelled probes and polymerase chain reaction, we detected human papilloma virus (HPV) 6/11 in 28 of 29 juvenile LP, in 26 of 30 adult multiple, and in 17 of 20 adult solitary LP. None of LP was found to harbour HPV types 16, 18, 31, 33, and 51. There were no clear-cut histological differences between juvenile and adult LP, the presence of koilocytosis was equally observed in both, and there was no prevalent type of epithelial hyperplasia in either form, except that all three cases of atypical hyperplasias (precancerous lesions) were found among adult patients. During a 14 year follow-up, no carcinomatous transformation of LP was observed. All juvenile LP in our study had frequent recurrences of the disease, however, numerous surgical procedures were also required in 16 of 27 adult patients. Our study supports Lindeberg's hypothesis of a similar pathogenesis for all forms of LP caused by the HPV types 6/11.

Adolescent↗