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M Poljak

Publications and source records attributed to M Poljak.

70 records · Page 4Linked to original sources
PubMed1994

p53 immunoreactivity in oligodendrogliomas.

Data are presented on p53 protein presence in human oligodendrogliomas whose progress from low grade to anaplastic oligodendroglioma can be followed. Expression was evaluated by formalin-fixed paraffin-embedded section immunohistochemistry, using monoclonal PAb 1801 antibody. The frequency of p53 protein accumulation is related to the stage of tumor malignancy. All the samples (100%) of malignant oligodendrogliomas were positive for p53 protein. Of 14 type II oligodendroglioma samples, 9 were positive (64%) while among type I oligodendroglioma the positivity was 28%. The mean proportion of reactive cells was also higher in malignant oligodendrogliomas. However, mean intensity staining did not differ among various grades of tumors. Our results point to the direct link between p53 protein accumulation and the malignant stage of human oligodendrogliomas. However, the value of p53 protein accumulation in predicting malignant behavior of oligodendrogliomas requires further confirmation.

Brain Neoplasms↗
PubMed1994

Isolation of a strain of a Hantaan virus from a fatal case of hemorrhagic fever with renal syndrome in Slovenia.

Hemorrhagic fever with renal syndrome (HFRS) has been serologically confirmed in Slovenia during the last seven years. There is evidence that three hantaviruses (Hantaan, Puumala, and a newly described form termed Dobrava) circulate simultaneously in this area. Recently, a hantavirus was isolated from the urine and brain tissue of a fatal case of HFRS. Positive immunofluorescent reactions with reference human sera and monoclonal antibodies were first recognized after the second cell culture passage. Extensive cross-reactivity between our isolate and prototype Hantaan virus, strain 76-118, and Hantaan-like isolates from the former Yugoslavia, Fojnica and Plitvice, was revealed by enzyme-linked immunosorbent assay with specific rat antisera. The reaction pattern of the isolate was similar to the prototype Hantaan virus by indirect immunofluorescent assay with a panel of monoclonal antibodies. Furthermore, the specificity of the isolates was confirmed by analysis of polymerase chain reaction products of this virus with five restriction endonucleases. This appears to be the first isolation of a strain of prototype Hantaan virus from a fatal case of HFRS in Europe.

Adult↗
PubMed1993

DNA amplification by polymerase chain reaction from brain tissues embedded in paraffin.

A method which enables analysis of DNA from archival paraffin embedded normal and malignant brain tissue is described. The demonstration of a 317-bp long beta-actin DNA sequence by the polymerase chain reaction (PCR) was used to identify which fixation procedure, deparaffinization time and DNA extraction procedure would give the best results. Tissue specimens 1-39 years old were included in the experiments. Specimens fixed in either 10% formalin, Carnoy's or AMeX fixative were found to be best suited for subsequent analysis by PCR. Paraformaldehyde and acetone compromised amplification efficiency, while Bouin's fixed tissue gave uniformly negative results. Regardless of fixative used, PCR reaction had to be run through at least 40 cycles. Prolonged deparaffinization time and phenol/chloroform extraction of DNA did not influence DNA quality as a template for PCR reaction. Formalin fixed brain tumours can be successfully used for DNA/PCR analysis even if they are up to 39 years old.

Base Sequence↗
PubMedDate not supplied

Evaluation of the Amplicor HCV test: experiences after 1 year of routine use in a diagnostic laboratory.

To evaluate the usefulness of a standardized commercial amplification assay for detection of hepatitis C virus (HCV) RNA, Amplicor HCV Test (Roche), a total of 1,204 serum samples from 888 patients was examined. Seven out of 443 anti-HCV-negative samples, 638 out of 729 anti-HCV-positive samples and four out of 32 anti-HCV-indeterminate samples tested HCV RNA positive by Amplicor in initial testing. One false-negative and five false-positive Amplicor results were found in initial testing, giving an overall sensitivity and specificity of the Amplicor HCV Test of 99.8% and 99.1%, respectively. Our study confirmed that the Amplicor HCV Test is a practical, rapid, sensitive and specific assay for detection of HCV RNA. However, the results must be interpreted with some caution and with the patient's anti-HCV status and clinical data in mind.

Blood Donors↗
PubMedDate not supplied

Evaluation of two commercial amplification assays for detection of Mycobacterium tuberculosis complex in respiratory specimens.

To evaluate the usefulness of two standardized commercially available amplification assays for the detection of Mycobacterium tuberculosis: Amplicor test (Roche) and MTD-Amplified direct test (Gen-Probe) a total of 281 respiratory specimens from 198 patients with symptoms of pulmonary diseases were examined and compared with conventional methods. Fifty-seven specimens were positive and 218 negative by both amplification assays. Three specimens were reactive by Amplicor only, and three by MTD only. In comparison with culture, the sensitivity, specificity, positive predictive value and negative predictive value were 96.0, 94.8, 80.0, and 99.1%, respectively, for the Amplicor test; the corresponding values were 94.0, 94.4, 78.3, and 98.6%, respectively, for the MTD. However, when 28 specimens from 14 patients on antituberculous therapy were excluded the improvement in PPV and specificity of both assays was obtained. In conclusion, both commercially available amplification tests are almost equally sensitive and specific and are suitable for the implementation in daily routine work in the specialized clinical laboratories.

Adolescent↗
PubMedDate not supplied

Tick-borne encephalitis: possibly a fatal disease in its acute stage. PCR amplification of TBE RNA from postmortem brain tissue.

Tick-borne encephalitis has occurred regularly in Europe since it was first diagnosed in 1931 by Schneider. The mortality rate of patients with this disease is 1-2%. Death usually occurs in the acute stage of illness. A case report of a 28-year-old patient from Slovenia, who died shortly after the onset of tick-borne encephalitis, is described. The clinical course of disease, results of serological tests, neuropathological findings and polymerase chain reaction amplification of parts of viral genome from postmortem brain tissues are presented.

Acute Disease↗
PubMedDate not supplied

AIDS-related body cavity-based lymphoma. A case report.

BACKGROUND: Body cavity-based lymphomas are rare malignancies in human immunodeficiency virus (HIV)-infected patients, but because of their unusual clinical, morphologic and immunophenotypic features, they are recognized as a distinct subgroup of lymphomas connected to human herpesvirus 8 (HHV-8) infection. CASE: A 39-year-old, HIV-positive, homosexual man was admitted to the hospital because of a left-sided pleural effusion that contained malignant lymphoid cells. He responded partially to a low-dose cyclophosphamide/doxorubycin/vincristine/prednisone regimen and died five months after the diagnosis of lymphoma. On cytology, the sediments contained exclusively large, round, neoplastic, lymphoid cells with abundant basophilic cytoplasm and large, round nuclei with prominent nucleoli. Many cells had immunoblastic features, and some had plasmocytoid differentiation. Mitotic figures were numerous. On flow cytometry, the homogeneous population of large cells expressed CD45, CD38, HLA-DR and CD7 positivity. Other specific T-, B- and NK-cell markers tested negative. Polymerase chain reaction demonstrated Epstein-Barr virus (EBV) and HHV-8 in the malignant effusion. CONCLUSION: Primary effusion from lymphoma with molecular evidence of HHV-8 and EBV coinfection represents a distinct clinical and morphologic entity in AIDS patients. However, immunophenotypic markers of malignant clones can be diverse in different cases.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Quantitative measurement of telomerase catalytic subunit (hTERT) mRNA in laryngeal squamous cell carcinomas.

We tested 30 laryngeal squamous cell carcinomas (LSCCs) and 30 matched control laryngeal samples from the same patients for the presence of human telomerase catalytic subunit (hTERT) mRNA by using the Roche LightCycler Telo TAGGG hTERT Quantification kit. The hTERT index was calculated to express the relative quantity levels of hTERT mRNA. hTERT mRNA was detectable in 10 out of 30 (33%) laryngeal tissues covered by normal and/or reactively hyperplastic laryngeal epithelium and 23 out of 30 LSCCs (77%). The mean hTERT indices were 0.15 for control non-cancerous laryngeal samples, 0.57 for grade I, 2.35 for grade II and 3.72 for grade III LSCCs. LSCCs without detectable hTERT mRNA (23%) tended to have lower grades of disease. No correlation was found between the levels of hTERT mRNA and tumour size or locoregional lymph node status. We believe that hTERT mRNA in normal and/or reactively hyperplastic laryngeal epithelium originates from the stem cells and corresponds to the self-renewal capacity of the squamous epithelium. However, the greater quantity of h TERT mRNA in LSCCs is the result of telomerase reactivation in the process of laryngeal carcinogenesis.

Adult↗
PubMedDate not supplied

Treatment of chronic hepatitis C: our experience.

BACKGROUND/AIMS: While an optimal treatment of chronic hepatitis C has not yet been established, it has been demonstrated that the interferon alpha/ribavirin combination is more effective than interferon alpha monotherapy. METHODOLOGY: One hundred and forty-three patients with chronic hepatitis C received the following treatment: eighty patients an 18-month monotherapy (3-month follow-up) and sixty-three patients a 12-month combined therapy (6-month follow-up). Therapeutic efficacy and adverse effects were compared. RESULTS: In 80 patients in the monotherapy group, complete response was achieved in 49.2%. This was reduced to 27.5% three months after therapy. Significant differences were observed in HCV 3 genotype where complete response was achieved in 12 out of 14 patients (p=0.01). With the combined therapy administered to 63 patients, complete response was achieved in 54.5%. This was reduced to 43.2% after 6 months of follow-up. Among the responders or partial responders, significant differences were observed with regard to age (p=0.0047) and subtype 1b (p=0.012). Comparing the groups of naive patients and relapsers, a statistically significant difference (p=0.027) was found in therapeutic efficacy. CONCLUSIONS: In the treatment of chronic hepatitis C, combined therapy proved more effective than monotherapy. This is, however, not yet a satisfactory solution.

Adolescent↗
PubMedDate not supplied

Human papillomavirus infection in esophageal squamous cell papillomas: a study of 29 lesions.

The etiology and pathogenesis of esophageal squamous cell papillomas (ESCP), rare benign tumors of human esophagus, are still controversial. Chronic mucosal irritation and infection with human papillomaviruses (HPV) are two proposed etiologies. To investigate these hypotheses, we screened 29 ESCPs from 28 patients originating from Slovenia and Poland for HPV infection using in situ hybridization (ISH) and polymerase chain reaction (PCR). No evidence of HPV DNA was found using ISH. By PCR, the presence of HPV DNA was detected in only one lesion using two different HPV L1 consensus primer sets. The restriction fragment analyses of PCR product showed patterns unique to HPV type 6. All other ESCPs were successfully amplified only with internal control human beta-globin primers. Our results show that HPV DNA is not frequently detectable in ESCPs, even when highly sensitive methods like PCR are used and that other pathogenetic mechanisms are more important in the etiology of ESCPs.

Base Sequence↗
PubMedDate not supplied

Human papillomavirus type 16 DNA in oesophageal squamous cell carcinoma.

Recent studies, mainly from high risk areas of oesophageal cancer (OC), have suggested a possible role of oesophageal infection with human papillomavirus (HPV) in the carcinogenesis of OC. Twenty-two cases of OC (among them 20 cases of squamous cell, 1 case of verrucous and 1 case of adenoid cystic carcinoma) originating from a middle risk area of OC, were analysed by in situ hybridization (ISH) and polymerase chain reaction (PCR) to demonstrate HPV infection. No evidence of HPV DNA was found using ISH. By PCR, the presence of HPV DNA was detected in 1/3 (33%) of early and 1/17 (5.7%) of advanced squamous cell carcinoma cases. After digestion of PCR products using seven restriction endonucleases, the restriction enzyme digestion patterns were found to be unique for HPV type 16 in both positive cases of OC. All other squamous cell carcinomas, the case of verrucous carcinoma and that of adenoid cystic carcinoma were successfully amplified only with internal control human beta-globin primers. Our results are comparable with those from high risk areas of OC and support the HPV may be involved in the carcinogenesis of this malignancy.

Base Sequence↗
PubMedDate not supplied

Overexpression of p53 protein in benign and malignant laryngeal epithelial lesions.

This study investigated the immunohistochemical expression of p53 protein in various laryngeal lesions using Kambic's classification from simple hyperplasia to invasive squamous cell carcinoma (SCC), and analyzed the relationship between p53 protein overexpression and the severity of epithelial abnormalities. p53 overexpression was observed in 10/19 (53%), in 9/16 (56%), and in 9/13 (69%) cases of simple, abnormal, and atypical hyperplasia respectively, and also in 8/10 (80%) cases of SCC. The proportion of immunoreactive cells and staining intensity increased with the progression of the epithelial hyperplastic lesions. Our study confirms the association of p53 protein overexpression with laryngeal epithelial hyperplastic lesions which have the potential to transform into malignancy, but considering the follow-up of the patients, p53 expression cannot be considered a reliable prognostic factor for any group of laryngeal epithelial hyperplastic lesions regardless of the severity of the lesions.

Adenocarcinoma↗
PubMedDate not supplied

p53 protein overexpression in laryngeal squamous cell papillomas.

We retrospectively investigated p53 protein immunoreactivity in 103 laryngeal squamous cell papillomas (LP) previously revealed to be human papillomavirus type 6 or 11 positive by in situ hybridization and/or the polymerase chain reaction. 21 LP failed to show any detectable level of p53 protein reactivity. In 45 cases only occasional strongly positive cells were observed in almost the whole thickness of the epithelium. In 26 LP, p53 protein immunoreactivity was found to be almost exclusively restricted to the basal epithelial cells. Finally, in 11 cases, basal cell layer immunoreactivity was accompanied by aggregates of p53-positive cells in the lower two thirds of the epithelium. This staining pattern was found predominantly in LP with atypical hyperplasia. We think that the observed patterns of p53 immunoreactivity in a majority of cases are a result of immunohistochemical detection of the stabilized wild-type p53 protein rather than the mutated p53 protein.

Adolescent↗