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C J Meijer

Publications and source records attributed to C J Meijer.

At least 145 records · Page 8Linked to original sources
PubMed1998

Non-random allelic losses at 3p, 11p and 13q during HPV-mediated immortalization and concomitant loss of terminal differentiation of human keratinocytes.

To obtain a comprehensive overview of chromosomal alterations that may underlie human papillomavirus (HPV)-mediated immortalization, 4 foreskin keratinocyte cell lines generated by transfection with either HPV 16 (cell lines FK16A and FK16B) or HPV 18 (FK18A and FK18B) were subjected to chromosomal analysis using comparative genomic hybridization (CGH). Three cell lines were analyzed both in the mortal state during their extended lifespan and in the subsequent immortal state. From cell line FK18A, only immortal cells were tested. Chromosomal imbalances increased in number through the process of immortalization. Subsequent loss of heterozygosity (LOH) analysis, using a panel of 21 microsatellite markers selected on the basis of CGH losses, revealed no clonal LOHs in cells at the mortal stage. However, in the immortal descendants 67% of underrepresentations detected by CGH were expressed as clonal LOH at the respective loci. Clonal LOHs at 3p, 11p and 13q were detected in 2 cell lines each and were thus considered non-random. Immortal cells of 1 cell line (FK18B) revealed LOH at all 3 loci. Moreover, all immortal cell lines displaying allelic losses at one or more of these loci shared a severely dysplastic phenotype after organotypic culturing, as shown previously. Therefore, loss-of-function mutations of genes at these loci, eventually in combination, are potentially involved in the process of HPV-mediated immortalization that is attended by a loss of terminal differentiation. Since chromosomal changes at these loci are also found in HPV-associated carcinomas in vivo, the HPV-transfected cell lines seem to provide a valuable model system for studying HPV-mediated carcinogenesis.

Alleles↗
PubMed1998

Differential T helper cell responses to human papillomavirus type 16 E7 related to viral clearance or persistence in patients with cervical neoplasia: a longitudinal study.

T-cell-mediated immune responses against oncogenic human papillomaviruses (HPVs) are believed to play a role in the prevention of cervical carcinogenesis. The in vitro production of interleukin 2 by CD4+ T helper (Th) cells in response to overlapping 20-mer peptides covering the HPV-16 E7 oncoprotein sequence was determined in 72 women with cytological evidence of premalignant cervical intraepithelial neoplasia (CIN) who participated in a nonintervention follow-up (FU) study. In addition, 15 HPV-16 + cervical carcinoma patients were tested. Positive Th cell reactivity was restricted to patients infected by HPV-16 and related types and showed a strong association with viral persistence and disease progression, as evidenced by the high frequency of positive responders among women with persistent HPV-16 infections who ended FU with high-grade CIN III lesions [14 of 15 (93%)]. Women with cervical carcinoma showed responses at a significantly reduced rate [7 of 15 (47%); P = 0.014]. Over the FU period (10-34 months), the level of E7-induced interleukin 2 production from the lymphocytes of CIN patients who had cleared HPV-16 infection showed an inverse correlation with time relative to the last positive HPV DNA test, with 8 of 13 of these patients showing positive responses after clearance. By contrast, among women with persistent HPV-16 infections and developing CIN III lesions (n = 8), there was a rise in Th cell activity over the course of FU. The majority of women responded to an immunogenic region in the carboxyl terminus of the E7 protein (amino acids 67-98). The observed HPV-16 E7-specific Th cell responses may develop as a consequence of increased antigen availability resulting either from clearance or from progression of cervical lesions.

Adult↗
PubMed1998

The viral origin of cervical cancer in Rabat, Morocco.

In Northern Africa, cervical cancer is the second most common cancer among women. The diagnosis is usually made in advanced stages, and mortality is high, yet few studies have investigated the role of human papillomavirus (HPV) and other risk factors in the etiology of cervical cancer. A hospital-based case-control study was completed at the Institut National d'Oncologie (INO) in Rabat, Morocco. The study included 214 cases of invasive cervical cancer and 203 controls. A structured questionnaire was used to investigate known and suspected risk factors for cervical cancer. A GP 5+/6+ polymerase chain reaction system was used to detect the presence of HPV DNA and HPV type distribution. Probes for 30 HPV types were used in one research laboratory. HPV DNA was the central risk factor and accounted for the large majority of the cases. The adjusted odds ratio (ORa) for any HPV was 61.6 (95% CI, 29.2-130) and the corresponding HPV attributable fraction (AF) was 92%. Among cases of cervical cancer, HPV 16 was the most common type (67.7%) followed by HPV 18. The HPV type-specific prevalence was similar for squamous cell carcinomas and adenocarcinomas. In multivariate adjusted or HPV-stratified analyses, in addition to the strong effect of HPV, other risk factors identified were sexual intercourse with multiple partners before the age of 20 and low socio-economic status. Use of oral contraceptives for 5 or more years and high parity were also found to be related to cervical cancer. Screening was rare in this population but offered substantial protection against cervical cancer. In Morocco, cervical cancer is a late sequel of a viral infection with certain HPV types. Developing screening programs for preneoplastic cervical lesions is a public health priority. When available, HPV vaccination would offer a relevant alternative for preventing cervical cancer.

Adenocarcinoma↗
PubMed1998

Causes of cervical cancer in the Philippines: a case-control study.

BACKGROUND: Among the numerous human papillomavirus (HPV) types, only types 16 and 18 have been formally classified as human carcinogens. To evaluate the associations of 33 HPV types and other risk factors with squamous cell carcinoma and adenocarcinoma of the cervix, we performed a hospital-based, case-control study in the Philippines. METHODS: The study included 356 case subjects who had histologically confirmed cervical cancer (323 incident cases of squamous cell carcinoma and 33 incident cases of adenocarcinoma/adenosquamous carcinoma) and 381 control subjects. Information on risk factors was obtained by personal interview. HPV DNA was detected in exfoliated cervical cells and biopsy specimens by use of a polymerase chain reaction assay. RESULTS: HPV DNA was detected in 93.8% of case subjects with squamous cell carcinoma and in 90.9% of case subjects with adenocarcinoma/adenosquamous carcinoma compared with 9.2% of control subjects, giving age-adjusted odds ratios of 156 (95% confidence interval [CI] = 87-280) for squamous cell carcinoma and 111 (95% CI = 31-392) for adenocarcinoma/adenosquamous carcinoma. Fifteen different HPV types were detected in squamous cell carcinoma, and six different HPV types were detected in adenocarcinoma/adenosquamous carcinoma. Among HPV types other than types 16 and 18, the associations of HPV with risk of squamous cell carcinoma were strongest for HPV45. In addition to HPV, high parity, low socioeconomic status, and smoking were also associated with both types of cervical cancer. CONCLUSIONS: As has been shown for squamous cell carcinoma, HPV is the central cause of adenocarcinoma/adenosquamous carcinoma of the uterine cervix. The observed associations of less prevalent HPV types with cervical cancer have important implications for cervical cancer prevention strategies.

Adenocarcinoma↗
PubMed1998

Risk factors for cervical cancer in Thailand: a case-control study.

BACKGROUND: Human papillomaviruses (HPV) types 16 and 18 are clearly involved in the etiology of cervical cancer, but the evidence for the carcinogenicity of other HPV types is limited. Cofactors involved in the progression from infection with HPV to high-grade precursors and cancer have not been clearly defined by the results of previous studies. METHODS: We conducted a hospital-based, case-control study of invasive cervical cancer to investigate risk in relation to HPV infection and its epidemiologic cofactors in Hat-Yai, Thailand. A total of 338 patients with squamous cell carcinoma, 39 patients with adenocarcinoma/adenosquamous carcinoma, and 261 control subjects were included in the study and were interviewed to obtain information with regard to cervical cancer risk factors. HPV DNA presence in cervical exfoliated cells or frozen biopsy specimens was determined by a polymerase chain reaction assay. RESULTS: HPV DNA was detected in 95% of patients with squamous cell carcinoma, 90% of those with adenocarcinoma/adenosquamous carcinoma, and 16% of control subjects. For patients with squamous cell carcinoma, the most common types of HPV found were type 16 (60% of the positives), type 18 (18%), type 58 (3%), type 52 (3%), and type 31 (2%). For patients with adenocarcinoma/adenosquamous carcinoma, the most common HPV types found were type 18 (60% of the positives), type 16 (37%), and type 45 (3%). The risk factors that remained associated with risk of both histologic types after adjustment for HPV and their mutual confounding effects were limited education, increasing number of sexual partners, history of venereal diseases, and interval since last Pap smear (i.e., cytologic) test. Among patients with squamous cell carcinoma, some association with smoking was also observed. CONCLUSION: New preventive strategies for cervical cancer will require the consideration of multiple HPV types.

Adenocarcinoma↗
PubMed1998

Risk factors for HPV infection in women from sexually transmitted disease clinics: comparison between two areas with different cervical cancer incidence.

We have compared risk factors for human papillomavirus (HPV) infection in very sexually active women [attenders of clinics for sexually transmitted diseases (STDs)] living in 2 areas with a 4-fold difference in cervical cancer incidence, i.e., Greenland and Denmark. The results were compared with findings of HPV infection in men attending the STD clinics during the same period. Overall, 204 Greenlandic women (GW), 187 Danish women (DW), 103 Greenlandic men and 216 Danish men were included. A similar age distribution was found in the 2 female populations. The GW reported significantly more sexual partners, earlier first intercourse and more STDs, but HPV was less frequently detected in the GW (25%) than in the DW (35%). However, this could be explained by a difference in the age pattern of HPV prevalence seen in the 2 areas. In each geographical area, the age pattern of HPV prevalence in men was very similar to that seen in women. The most important risk factors for HPV detection were the same in both female populations, i.e., age, years since first sexual intercourse and number of partners in the last years. In conclusion, the pattern of risk factors for HPV infection was the same in STD women from a high-risk area and a low-risk area for cervical cancer. Our results also show that the use of an overall HPV prevalence for comparing populations is meaningless, even in populations with similar age distribution.

Adolescent↗
PubMed1998

p53 expression above the basal cell layer in oral mucosa is an early event of malignant transformation and has predictive value for developing oral squamous cell carcinoma.

Epithelial dysplasia is usually used to establish the prognosis of oral premalignant lesions. Its assessment, however, is subjective and does not always correctly predict the outcome of the lesions in terms of malignant transformation. Early molecular alteration(s) that dictate the development of cancer should be identified and used to evaluate oral premalignant lesions. In this context, alterations in the expression of p53 were investigated. Thirty-five oral premalignant lesions and 11 carcinomas that developed from them in a period of 16 years were investigated for p53 expression by immunohistochemistry. Normal oral mucosa from healthy individuals and oral benign lesions were used as controls. In benign lesions and normal mucosa, p53 staining, when present, was confined to the basal cell layer. Seven out of 35 (20 per cent) premalignant lesions showed p53 expression clearly above the basal cell layer and six of these (86 per cent) developed carcinomas. Suprabasal p53 expression was found in three lesions with no or mild dysplasia that developed carcinomas. All carcinomas derived from premalignant lesions with p53 suprabasal expression showed p53 expression in neoplastic cells. The combined use of histological parameters (presence of moderate or severe dysplasia) with p53 expression patterns (p53 staining above the basal cell layer) showed the highest sensitivity for the detection of lesions that progressed to carcinoma (91 per cent). When used individually, the p53 expression pattern showed higher specificity than assessment of dysplasia (96 per cent vs. 54 per cent) and higher positive predictive value (86 per cent vs. 44 per cent) for correct prediction of the malignant transformation of the lesions. The results suggest that clear expression of p53 above the basal cell layer is an early event in oral carcinogenesis and an indicator of a developing carcinoma, even preceding morphological tissue alterations. However, since immunohistochemistry cannot always detect changes in p53 expression in lesions preceding carcinoma, p53 immunohistochemical analysis is strongly recommended in conjunction with histological parameters, to increase the sensitivity of detection of cases that will progress to carcinoma.

Adult↗
PubMed1998

Expression of proliferation and apoptosis-related proteins in usual ductal hyperplasia of the breast.

Expression of proliferation- and apoptosis-related proteins was studied by immunohistochemistry in 130 usual ductal hyperplasias of the breast, of which 39 cases (30%) had adjacent invasive cancer. Overexpression of cyclin D1 and Ki-67 was found in 6% and 29% of the cases, respectively. Only two mild ductal hyperplasias were Her-2/neu positive. Overexpression of p21 and reduced expression of p27, both cdk-inhibitors, was seen in 16% and 27% of the lesions, respectively. Reduced expression of bcl-2 was found in 16% of the cases, and p53 accumulation was present in 8%. Expression of six of the seven studied proteins showed no significant difference between mild, moderate, or florid ductal hyperplasias, indicating that there are no important cell biological differences with regard to the studied proteins between the lesions within this morphologically continuous spectrum. In addition, there were no differences between lesions with and without an invasive component. Cyclin D1 positivity was exclusively seen in lesions with 75% or more p27-positive nuclei. No significant correlations were found between other proteins. Twenty-three of 91 lesions (25%) had multiple events, of which five showed altered expressions of three or four proteins. In conclusion, altered protein expression of several proliferation- and apoptosis-related genes that are known to be involved in invasive breast cancer also may be found in usual ductal hyperplastic lesions, including several lesions with multiple events. This implies that usual ductal hyperplastic lesions may be among the earliest lesions within the breast oncogenetic spectrum.

Apoptosis↗
PubMed1998

Tracing the origin of adenocarcinomas with unknown primary using immunohistochemistry: differential diagnosis between colonic and ovarian carcinomas as primary sites.

To discriminate adenocarcinoma metastases originating from either colon or ovary, a panel of immunohistochemical markers was evaluated. For this purpose, paraffin sections from 157 primary and metastatic colonic and ovarian carcinomas were immunostained. These cases were divided into a learning group of 46 colonic and 54 ovarian carcinomas and a test group of 29 colonic and 28 ovarian carcinomas, including all metastatic tumors, among which were five with unknown primary site at the time of testing. The sections were immunostained with antibodies against carcinoembryonic antigen (CEA), cytokeratin 7 (CK7), cytokeratin 20 (CK20), CA125, vimentin, and CA19.9. Staining results were expressed as the product of staining intensity and percentage of positive tumor cells. Stepwise discriminant analysis was applied on the learning set to obtain a classification function for both tumors. The validity of the classification function was evaluated using the test set. There was considerable overlap in immunostaining for both tumor types, but colonic carcinomas were typically positive for CEA and CK20 and negative for CK7 and CA125. Ovarian carcinomas were typically positive for CK7 and CA125 and negative for CEA and CK20. In discriminant analysis, the best combination of markers appeared to be CK7 and CEA. Only one sample of the test group (2%) was misclassified. Taking learning and test groups together, 136 of the 157 samples (87%) were correctly classified with high posterior probability (PP > .8). However, from the 28 mucinous ovarian carcinomas, only 19 (68%) could correctly be classified with high PP. When excluding the nonmucinous ovarian carcinomas from the analysis, overall 87 of 103 (84.5%) of the samples were correctly classified (PP > .8) with a combination of CEA, CK7, and also vimentin. From the 28 mucinous ovarian carcinomas, only two (7%) were misclassified, and four could not be classified with sufficient certainty. In neither analysis did CK20, CA125, or CA19.9 emerge as discriminatory parameters. Based on the same data, an intuitive flow chart was constructed with which 129 of 157 cases could be classified (only one falsely) without further statistical analysis. The five metastases with an at first unknown primary could, according to the follow-up, all be classified correctly with high PP. Most ovarian carcinomas, including the mucinous ones, can be discriminated with high probability from colonic carcinomas using a panel of three antibodies directed against CEA, cytokeratin 7, and vimentin.

Adenocarcinoma↗
PubMed1998

Benign anal lesions, inflammatory bowel disease and risk for high-risk human papillomavirus-positive and -negative anal carcinoma.

A central role in anal carcinogenesis of high-risk types of human papillomaviruses (hrHPV) was recently established, but the possible role of benign anal lesions has not been addressed in hrHPV-positive and -negative anal cancers. As part of a population-based case-control study in Denmark and Sweden, we interviewed 417 case patients (93 men and 324 women) diagnosed during the period 1991-94 with invasive or in situ anal cancer, 534 patients with adenocarcinoma of the rectum and 554 population controls. Anal cancer specimens (n = 388) were tested for HPV by the polymerase chain reaction. Excluding the 5 years immediately before diagnosis, men, but not women, with anal cancer reported a history of haemorrhoids [multivariate odds ratio (OR) 1.8; 95% confidence interval (CI) 1.04-3.2] and unspecific anal irritation (OR 4.5; CI 2.3-8.7) significantly more often than controls. Women with anal cancer did not report a history of benign anal lesions other than anal abscess to any greater extent than controls, but they had used anal suppositories more often (OR 1.5; CI 1.1-2.0). Patients with hrHPV in anal cancer tissue (84%) and those without (16%) reported similar histories of most benign anal lesions, but anal fissure or fistula was more common among hrHPV-positive cases. Ulcerative colitis and Crohn's disease, reported by <1% of study participants, were not associated with anal cancer risk. The higher proportion of hrHPV-positive anal cancers among case patients with anal fissure or fistula suggests that such mucosal lesions may provide direct viral access to basal epithelial layers. Since risk associations with benign anal lesions in men may be confounded by unreported sexual behaviour, and since risk associations in women were generally negative, it seems unlikely that benign anal lesions act as promoters in hrHPV-associated anal carcinogenesis. Moreover, benign anal lesions appear not to be linked to an alternative, hrHPV-unassociated causal pathway to anal cancer. Ulcerative colitis and Crohn's disease were not supported as causal factors for anal cancer.

Abscess↗
PubMed1998

Differentiation and cell-type-restricted expression of HOXC4, HOXC5 and HOXC6 in myeloid leukemias and normal myeloid cells.

HOX genes have shown a lineage-specific expression in hematopoiesis and are suggested as being involved in the expression of certain adhesion molecules. Recently, we have demonstrated that HOXC4 and HOXC6, but not HOXC5, are expressed during lymphoid differentiation. Reports on the expression of these genes in myeloid leukemias and normal myeloid cells are still scarce. Therefore, we have investigated the expression of HOXC4, HOXC5 and HOXC6 in purified subpopulations of bone marrow in addition to 36 specimens of acute myeloid leukemias (AMLs), eight chronic myeloid leukemias (CMLs), several myeloid cell lines and cutaneous localizations of three myelomonocytic leukemias and one granulocytic sarcoma by RT-PCR and partly by RNA in situ hybridization (RISH). HOXC4 and HOXC6 transcripts were both detected by RT-PCR in 22/36 and 24/36 AMLs, respectively. The distribution of HOXC4 and HOXC6 gene expression over the different types of AML was largely similar and covered all types of AML. In contrast, HOXC5 gene expression was found in only 6/32 AMLs. Expression of HOXC5 was restricted to AMLs of the granulocytic (FAB M1-M3), early monocytic (FAB M4) and early erythroid (FAB M6) lineage. In general, except in one FAB M5b case, no expression of HOXC5 was found in AMLs derived from late stages of monocytic (FAB M5) and megakaryocytic (FAB M7) lineages. As for HOXC4 and HOXC6, expression of HOXC5 was absent in CMLs. Using RISH significant HOXC4, HOXC5 and HOXC6 expression was found in a number of additionally studied AML samples of different FAB classification (M2, M4, M5b and M5b), (M2 and M5b) (M2, M4, M5b), respectively. In tissue localizations of leukemias a different expression pattern of HOXC4, HOXC5 and HOXC6 was found. In contrast to mature leukemic stages of myeloid differentiation, these skin localizations of leukemias expressed HOXC5 and HOXC6. HOXC4 expression was found both in leukemic cells derived from peripheral blood and from cutaneous localizations. Besides HOXC4 expression in monocytes no expression of HOXC4, HOXC5 and HOXC6 was found in granulocytes and monocytes, colonies of growth factor-induced CD34+ bone marrow cells. In earliest CD34+/CD38low and high cell fractions of bone marrow only HOXC4 and in megakaryocytic cells both HOXC4 and HOXC6 were found. Thus, the expression patterns of these HOXC genes found in the limited number of cell fractions of normal bone marrow suggest that the expression patterns found in AMLs and CMLs might reflect the normal situation. Furthermore, the presence of HOXC5 and HOXC6 expression specifically in skin infiltrates of late differentiation stages of myeloid leukemias, suggests an additional role for these genes in the positioning of these myeloid cells in skin tissue.

Acute Disease↗
PubMed1998

Value of a panel of antibodies to identify the primary origin of adenocarcinomas presenting as bladder carcinoma.

AIMS: Adenocarcinomas may arise primarily from the urinary bladder, but secondary involvement from adenocarcinomas arising in adjacent organs is more common. In the present study we tried to differentiate primary urinary bladder adenocarcinomas from adenocarcinomas arising from the surrounding organs, based on their antigen profiles in routinely processed, paraffin-embedded tissue specimens. We analysed the staining results using stepwise linear discriminant analysis. METHODS AND RESULTS: We investigated the usefulness of a panel of antibodies against cytokeratin 7, E48, cytokeratin 20, PSA, PSAP, CEA, vimentin, OC125 and HER-2/neu, to discriminate primary bladder adenocarcinoma from adenocarcinomas arising from the prostate, urachus, colon, cervix, ovary and endometrium. In the differential diagnosis with urinary bladder adenocarcinoma, an overall correct classification was reached for 77% and 81% of urachal and colonic carcinomas, respectively, using CEA, for 93% of prostatic adenocarcinomas using PSA, for 82% and 70% of cervical and ovarian adenocarcinomas, respectively, using OC125, and for 91% of endometrial adenocarcinomas using vimentin. Adding other antibodies did not improve the classification results for any of these differential diagnoses. CONCLUSIONS: For the surgical pathologist, a panel of antibodies consisting of CEA, PSA, OC125 and vimentin is helpful to differentiate primary urinary bladder adenocarcinomas from adenocarcinomas originating from prostate and endometrium, less helpful in differentiation with urachal carcinoma, and not helpful in differentiation with colonic, cervical and ovarian carcinoma.

Abdominal Neoplasms↗
PubMed1998

Genotyping of Chlamydia trachomatis in urine specimens will facilitate large epidemiological studies.

The serovars of Chlamydia trachomatis-positive urine specimens (n = 81; as detected by PCR and ligase chain reaction) were successfully analyzed in 94% of cases by omp1 PCR-based RFLP analysis. The use of urine specimens and this simple and sensitive typing method will greatly facilitate epidemiological studies of C. trachomatis serovar distribution in asymptomatic C. trachomatis infections in both females and males.

Carrier State↗
PubMed1998

Nucleic acid sequence-based amplification, a new method for analysis of spliced and unspliced Epstein-Barr virus latent transcripts, and its comparison with reverse transcriptase PCR.

Nucleic acid sequence-based amplification (NASBA) assays were developed for direct detection of Epstein-Barr virus (EBV) transcripts encoding EBV nuclear antigen 1 (EBNA1), latent membrane proteins (LMP) 1 and 2, and BamHIA rightward frame 1 (BARF1) and for the noncoding EBV early RNA 1 (EBER1). The sensitivities of all NASBAs were at least 100 copies of specific in vitro-generated RNA. Furthermore, 1 EBV-positive JY cell in a background of 50,000 EBV-negative Ramos cells (the relative sensitivity) was detected by using the EBNA1, LMP1, and LMP2 NASBA assays. The relative sensitivity of the EBER1 NASBA was 100 EBV-positive cells, which was probably related to the loss of small RNA molecules during the isolation. The BARF1 and LMP2 NASBAs were evaluated on clinical material. BARF1 expression was found in 6 of 7 nasopharyngeal carcinomas (NPC) but in 0 of 22 Hodgkin's disease (HD) cases, whereas LMP2 expression was found in 7 of 7 NPCs and in 17 of 22 HD cases. For detection of EBNA1 transcripts in HLs (n = 12) and T- and B-cell non-Hodgkin's lymphomas (n = 3 and n = 2, respectively), NASBA was compared with reverse transcriptase (RT) PCR. Two samples were positive only with NASBA, and two other samples were positive only with RT-PCR; for all other samples, the RT-PCR and NASBA results were in agreement. We conclude that NASBA is suitable for sensitive and specific detection of the above-mentioned EBV transcripts, regardless of their splicing patterns and the presence of EBV DNA. The EBNA1, LMP2, and BARF1 NASBAs developed in this study proved to be reliable assays for detection of the corresponding transcripts in EBV-positive clinical material.

Base Sequence↗
PubMed1998

Serotyping and genotyping of genital Chlamydia trachomatis isolates reveal variants of serovars Ba, G, and J as confirmed by omp1 nucleotide sequence analysis.

Urogenital isolates (n = 93) of Chlamydia trachomatis were differentiated into serovars and variants by serotyping with monoclonal antibodies and genotyping by restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified omp1 gene, respectively. The types of 87 of the 93 isolates (94%) were identical, as determined by both methods. Among these 87 isolates, 3 isolates were identified as the recently described new serovariant Ga/IOL-238 by omp1 nucleotide sequence analysis of the variable domains. Of the remaining six isolates, three isolates serotyped as both L2 and Ba but were identified as Ba/A-7 by genotyping by RFLP analysis of omp1. The omp1 nucleotide sequences of variable domains VD1, VD2, and VD4 of these urogenital Ba strains were identical to the sequences of the variable domains of Ba/J160, an ocular Ba type. The three remaining isolates were serotyped as J, but the patterns obtained by RFLP analysis of omp1, which were identical for the three isolates, differed from that of prototype serovar J/UW36. omp1 nucleotide sequence analysis revealed that these strains are genovariants of serovar J/UW36. Nucleotide sequence differences between serovar J/UW36 and this J genovariant, designated Jv, were found in both variable and constant domains. In conclusion, this study shows that the PCR-based genotyping of clinical C. trachomatis isolates by RFLP analysis of omp1 has a higher discriminatory power and is more convenient than serotyping. Variants of C. trachomatis serovars Ba, G, and J were identified and characterized.

Antibodies, Bacterial↗
PubMed1998

Viral E6-E7 transcription in the basal layer of organotypic cultures without apparent p21cip1 protein precedes immortalization of human papillomavirus type 16- and 18-transfected human keratinocytes.

Organotypic cultures of human keratinocytes provide a useful model system to study human papillomavirus (HPV)-host cell interactions. In this study, we analyzed organotypic cultures of two HPV type 16 (HPV16) (FK16A and FK16B)- and two HPV18 (FK18A and FK18B)-transfected keratinocyte cell lines through the process of immortalization in vitro. For FK16A and FK18B cells, passages of both mortal cells in their extended life span and subsequent immortal stages were studied. Mortal cells of FK16A and FK18B showed a morphology reminiscent of mild to moderate dysplasia, whereas in their immortal descendants, severely dysplastic features were observed. Immortal FK18A cells were mildly to moderately dysplastic, while FK16B cells were severely dysplastic. The increasing degrees of dysplasia were associated with a decreasing expression of differentiation markers cytokeratin 10 and profilaggrin. All raft cultures expressed E6-E7 mRNAs in the basal layer, while the amount of viral transcripts in the suprabasal cells was in general proportional to the degree of dysplasia. In all cases, E6-E7 transcription and dysplastic features were highly correlated with cellular proliferation, as assessed by Ki-67 (MIB-1) antigen expression. Moreover, high levels of E6-E7 transcription and expression of p21cip1 protein in the basal layer seemed to be mutually exclusive. We conclude that expression of E6-E7 in the basal cells associated with increased proliferation in the absence of detectable p21cip1 protein is apparently necessary but not sufficient for immortalization, or for the loss of terminal differentiation, for which yet to be discovered additional events are required. The model system described in this study provides a valuable tool to analyze alterations in viral transcription regulation during HPV-mediated cell transformation.

Cell Division↗