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Biomedical subjects

T Löning

Publications and source records attributed to T Löning.

At least 91 records · Page 5Linked to original sources
PubMed1994

Human papillomavirus DNA in oral squamous cell carcinomas and normal mucosa.

Human papillomavirus (HPV) infections in oral carcinomas and normal oral mucosa were studied by consensus primer screening and typing for HPV types 6/11, 16 and 18 DNA. After polymerase chain reaction (PCR) the DNA species of interest were identified by Southern blot hybridization with digoxigenin-labeled oligonucleotide probes. Frozen tissue and scrapings were equally suitable for HPV testing and yielded high HPV detection rates in carcinomas. By comparison, HPV analysis of paraffin-embedded material was much less efficient. HPV were demonstrated in 61.5% (16/26) of oral squamous cell carcinomas, high risk HPV 16 and 18 being the preferential types. The frequency of HPV detection in non-neoplastic mucosa of tumor patients decreased clearly with increasing distance from the tumor (range 26.9-3.8%) suggesting focal HPV infections. In contrast, normal buccal mucosa of a group of healthy volunteers contained HPV DNA only in 1% (1/97).

Adolescent↗
PubMed1994

[p53 alterations and HPV status in oral squamous cell carcinomas].

Immunohistochemical examination of p53 protein accumulation, analysis of the p53 gene using amplification of the exons 5-8 followed by TGGE, and PCR based HPV typing were carried out on 40 oral squamous cell carcinomas. 28 of 40 oral carcinomas (70%) contained DNA of the oncogenic HPV types 16 and 18. A p53 accumulation was present in 20 of 37 tumors (54%). Mutations of the p53 gene were detected in 15 of 39 carcinomas (38%). 15 of 20 oral carcinomas with abnormal p53 expression and 11/15 tumors with mutations of the p53 gene were HPV positive. Our results demonstrate a frequent occurrence of p53 abnormalities in HPV positive oral squamous cell carcinomas. This pattern is divergent from HPV related genital carcinomas and could reflect differences in the etiology of squamous cell carcinomas of different sites.

Biopsy↗
PubMed1993

Cell types infected in human cytomegalovirus placentitis identified by immunohistochemical double staining.

Chronic villitis is almost always present in intrauterine infection with human cytomegalovirus (HCMV). The inflammatory response to this virus has been described in detail. However, little is known about the types of placental cells that may be infected by HCMV and six cases of HCMV placentitis were thus investigated to identify the vulnerable cell types. Immunohistochemical double staining analyses were performed using antibodies to HCMV immediate early antigens and to specific cellular marker proteins. Fixed connective tissue cells could be demonstrated to be the predominantly infected cell type in each placental tissue. Endothelial cells and macrophages were also found to be infected in all six cases, whereas evidence of trophoblast infection was obtained in four cases. It is concluded that release of infectious virus by connective tissue cells, macrophages and endothelial cells may play a critical role in transplacental transmission of HCMV. The findings further suggest that the cytopathic effect of HCMV infection on these cells might be involved in the pathogenesis of intrauterine HCMV disease.

Antigens, Viral↗
PubMed1993

Human papillomavirus detection in cervical adenocarcinoma by polymerase chain reaction.

Twenty-five primary cervical adenocarcinomas and five cervical infiltrates from endometrial or rectal adenocarcinomas were analyzed for human papillomavirus (HPV) DNA by polymerase chain reaction with consensus and type-specific primers. Sixty-four percent (16 of 25) of the primary carcinomas and 20% (one of five) of the secondary infiltrates were positive for HPV types 16 and/or 18 DNA. Among the primary tumors HPV DNA was found in 80% of the endocervical cell-type tumors and in 60% of the endometrioid tumors, whereas two undifferentiated scirrhous carcinomas, one clear cell carcinoma, and one serous-papillary tumor were HPV negative. Human papillomavirus-positive patients were younger than HPV-negative patients (mean ages, 49.2 v 64.2 years). Our results indicate that papillomavirus play a major role in the etiology of cervical adenocarcinomas, at least in premenopausal women. However, in contrast to other studies, HPV type 18 was not the predominant type of HPV, HPV types 16 and 18 occurring with similar frequency in our patients.

Adenocarcinoma↗
PubMed1993

[p53 in urogenital tumors:analysis of expression and mutation].

DNA and paraffin material of more than 100 tumors of prostate, bladder and female genital organs were analyzed for p53 aberrations and compared with normal tissues by immunohistochemistry, PCR of p53 exons 5-8 and TGGE. While normal tissues, precancerous and borderline lesions, and well differentiated carcinomas usually showed wild type p53 and negative immunostaining, high grade and/or high stage carcinomas often revealed mutant p53 (rate of mutation in exon 8 >> 7 >> 6 >> 5) and/or p53 accumulation. Accumulation of p53 protein in the absence of detectable mutant p53 was recognized more often in prostate cancer than in any other tumor examined. Although p53 aberration probably represents a late molecular event in cancerogenesis, its detection may be of clinical interest as genetic footprint in recurrent and metastatic disease.

DNA, Neoplasm↗
PubMed1993

Comparative DNA image cytometry in imprint-, cytospin- and tissue section preparations of breast carcinoma.

Histologic sections, imprint preparations and cell preparations by enzymatic lysis from thick sections of cases of breast carcinomas were used to study total nuclear DNA distribution by image cytometry. Histologic sections are a prerequisite to unequivocally identify tumour cells as well as whole connective tissue cells used as a standard. While imprint preparations and lysis preparations are quite comparable with respect to distributional features, only one of them suffices to recognize these features, especially peaks at higher ploidies. Using this two-method approach to breast carcinomas, it was possible to distinguish a distribution separate from previously recognized distributions: a distinct triploid peak appears for predominantly high grade malignant ductal carcinomas.

Breast Neoplasms↗
PubMed1992

A simple and rapid technique to process formalin-fixed, paraffin-embedded tissues for the detection of viruses by the polymerase chain reaction.

The use of chelating resin in a simple, rapid and efficient pre-treatment protocol to process formalin-fixed, paraffin-embedded specimens for the polymerase chain reaction (PCR) is described and compared to other pre-treatment techniques. With this modified PCR protocol, a variety of human autopsy and biopsy specimens were investigated for presence of DNA of human papilomaviruses, cytomegalovirus or Epstein-Barr virus. These viruses were detected in a productive or non-/low-productive state. Amplimers generated ranged from 88 to 450 base pairs length. Under the specified technical conditions, a considerable range of DNA molecules can be amplified from paraffin-embedded material, some older than 10 years.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Rejection, herpesvirus infection, and Ki-67 expression in endomyocardial biopsy specimens from heart transplant recipients.

We examined 164 endomyocardial biopsy specimens from 29 patients who received an orthotopic heart transplant since 1984. Rejection was graded according to the Hannover classification. Non-isotopic in situ DNA hybridization was conducted on cryostat sections with biotinylated probes for herpes simplex virus, Epstein-Barr virus, and cytomegalovirus. Serial sections of 126 biopsies were investigated immunohistochemically for the presence of activated T lymphocytes and proliferating cells, with monoclonal antibodies against interleukin 2 receptors (CD 25) and Ki-67 antigen. Relations between rejection grades, presence of proliferating cells, and presence of herpesvirus DNA were determined for the total number of biopsies. For some patients correlation of these parameters was studied over time. Herpesviral nucleic acids were detected in 25% of all biopsies: 37% of biopsies with relevant rejection (grades A 2 or A 3; 39% of all biopsies) compared to 18% of biopsies graded A 0, A 1, or A 5 (61% of all samples) (P less than 0.01). 56% of the biopsies with infection showed relevant rejection as compared with only 33% of the uninfected. Ki-67 expression was found in 41% of all biopsies, mainly in infiltrating cells: 69% of biopsies with relevant rejection compared with 23% of cases of minor/no rejection (P much less than 0.001). Ki-67 expression was also associated with herpesvirus infection: 66% of infected biopsies contained Ki-67 positive cells compared with 33% of uninfected biopsies (P less than 0.001). Herpesvirus infection was usually observed within the interstitial cell population, which, in many cases, displayed a considerable Ki-67 expression, too. In few cases only, hybridization was unequivocally found in vascular wall cells or myocytes. Viral myocarditis does not only mimic graft rejection morphologically, but it may also affect the course of rejection, via induction of antigenic changes or direct injury of cardiac tissues. Virus infections may also elicit or aggravate obliterative coronary artery disease, and thus contribute to accelerated graft atherosclerosis.

Adult↗
PubMed1992

Cytomegalovirus detection in kidney transplants: results obtained from the polymerase chain reaction.

Kidneys from twelve renal transplant recipients were examined prior to and after graft failure and explantation. The investigations included conventional light and electron microscopy and the analysis of human cytomegalovirus-related viral proteins and viral DNA. Nucleic acid hybridization studies were conducted on kidney explants by an in situ method using DNA probes and by the polymerase chain reaction employing primers and probe for immediate early gene targets. In none of the cases did light and electron microscopy including immunohistochemistry for human cytomegalovirus reveal active infection in punch biopsies or explants. Interestingly, in situ hybridization also failed to detect human cytomegalovirus even in two cases with seroconversion, while the polymerase chain reaction was positive. The polymerase chain reaction disclosed only two additional positive cases within the residual group of explanted kidneys. In our hands, the polymerase chain reaction was the only potent direct detection method for cytomegalovirus in transplanted human kidneys.

Adult↗
PubMed1992

Detection of N-myc gene amplification in bone marrow specimen of stage IV neuroblastoma patients.

N-myc gene amplification is an unfavorable prognostic factor in neuroblastoma; therefore, its detection might have therapeutical consequences. Because of the reliability of noninvasive diagnostic methods such as X-ray examination and measurement of vanilymandelic acid and the lack of technical unavailability at most institutions, the determination of the N-myc status of neuroblastoma often is not done. In our investigation of 14 neuroblastoma patients, we could demonstrate N-myc gene amplification in the bone marrow of 5 patients with neuroblastoma stage IV disease and in bone marrow infiltration without enrichment of neuroblastoma cells. Otherwise, no information about the tumor content of N-myc gene copies at the time of initial diagnosis could be obtained. At the subsequent resection, the N-myc gene amplification was confirmed by the additional Southern blot analysis and in situ hybridization of tumor tissue. Furthermore, the N-myc status of bone marrow was analyzed during the stages of chemotherapy in three cases.

Blotting, Northern↗
PubMed1991

Comparative investigation of c-erbB2/neu expression in head and neck tumors and mammary cancer.

Normal tissues, primary tumors, and metastases of mammary and salivary glands and oral/laryngeal mucosa have been analyzed with Northern-blots employing 32P-labeled RNA probes for the expression of the neu oncogene. Neu oncogene expression of a mRNA species of 4.6 kilobases was found in all normal salivary (five) and mammary glands (four) as well as in two normal or inflamed samples of tongue mucosa. This expression was regarded as baseline activity of the neu gene for the respective tissues and was used as standard for the evaluation of benign and malignant tumors. None of 14 squamous cell carcinomas of the oral and laryngeal mucosa showed enhanced neu transcription level. Five fibroadenomas, one benign variant of phylloid tumor, one carcinosarcoma, and one of two proliferative fibrocystic diseases of the breast showed lacking or normal baseline expression of the neu oncogene, as did one monomorphous cystadenolymphoma of the parotid gland. In contrast, four parotid pleomorphic adenomas and one salivary gland adenocarcinoma showed enhanced neu expression. For mammary adenocarcinomas, increased neu oncogene expression concerned ten of 34 cases--all being variants of ductal carcinomas--and all metastases analyzed (six) deriving from three primaries. One adenoid cystic carcinoma also showed enhanced neu expression. Neu overexpression may reflect accidents of genomic reconstitutional events occurring regularly within the differentiation pathway of epithelial/myoepithelial cells. This assumption was supported by further immunohistochemical analysis which showed stainings of myoepithelial and myoepithelia-like cell populations in tumors, especially pleomorphic adenomas and adjacent normal-looking tissues.

Adolescent↗
PubMed1991

Herpes simplex virus type-2 ulcers resistant to acyclovir in an AIDS patient--successful treatment with foscarnet.

The case of a 25-year-old homosexual man with large inguinal and perianal ulcers is reported. He had been pretreated extensively with acyclovir. Herpes simplex virus (HSV) was identified in the ulcer tissue by in-situ hybridization. No clinical improvement with acyclovir but a prompt response to foscarnet was noted. In a relapse after 11 weeks an acyclovir-resistant HSV type 2 was isolated. Again, a prompt response to foscarnet was noted. The case is presented in detail, and the clinical impact of resistance of HSV to acyclovir is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Human papillomavirus infection in vulvar lesions of lichen sclerosus et atrophicus.

Human papillomaviruses (HPV) types 6, 11, 16 and 18 infections were investigated in 18 vulvar lesions of lichen sclerosus et atrophicus (LSA) using in situ DNA hybridization and polymerase chain reaction (PCR) on formalin-fixed paraffin-embedded specimens. Four out of 18 specimens were found to be infected with HPV type 16 using the PCR technique. Interestingly, three of these four patients were in a premenopausal state. This difference proved to be the only distinguishing feature in a comparison of HPV type 16-infected patients with non-infected patients. In situ hybridization revealed no positive result in any case and PCR demonstrated no HPV-DNA type 6, 11 or 18. Patients with HPV type 16-infected lesions may be regarded as at risk of developing vulvar cancer. Therefore, long-term follow-up of this subgroup is particularly important.

Adult↗
PubMed1991

Human papillomavirus and c-myc/c-erbB2 in uterine and vulvar lesions.

The aim of this study was to investigate papillomavirus (HPV)-DNA in precancer and cancer of the cervix, vulva, and endometrium by in situ/dot blot/Southern blot hybridization and polymerase chain reaction (PCR). Myc/erbB-2 expression was examined by Northern blot analysis. PCR was the most sensitive HPV detection method, demonstrating HPV-DNA in all pre-invasive and invasive cervical lesions (n = 21) and most (3 of 4) vulvar carcinomas in contrast to an overall rate of 60% with other techniques. Particular phenotypes (adenoid cystic/basal cell carcinoma of the vulva, cervical adenocarcinoma) were found to contain HPV. Endometrium harboured HPV not only in two cases of cervical cancer, but also in 3 of 8 primary endometrial carcinomas and 3 of 8 non-malignant conditions. Myc activation was confined to three squamous cell carcinomas, most markedly in one HPV-6-positive verrucous variant. ErbB-2 over-expression was only seen in one HPV-18 infected advanced endometrial tumour. Our findings point to a range of HPV-infected lesions broader than previously supposed and possible contributions of HPV-independent molecular events to carcinogenesis in this field.

Base Sequence↗