Biomedical subjects

Kathrin U Jansen

Publications and source records attributed to Kathrin U Jansen.

32 records · Page 2Linked to original sources

PubMed2004

Reproductive tract infections in rural women from the highlands, jungle, and coastal regions of Peru.

OBJECTIVE: To define the prevalences and manifestations of reproductive tract infections (RTIs) in rural Peruvian women. METHODS: During 1997-98, we visited 18 rural districts in coastal, highlands, and jungle regions of Peru. We administered standardized questionnaires and pelvic examinations to members of women's community-based organizations; and collected vaginal fluid for pH, amine odour, Gram stain, microscopy, and culture for Trichomonas vaginalis; cervical specimens for Chlamydia trachomatis, Neisseria gonorrhoeae; human papilloma virus (HPV) by polymerase chain reaction (PCR) assays, and blood for syphilis serology. FINDINGS: The 754 participants averaged 36.9 years of age and 1.7 sex partners ever; 77% reported symptoms indicative of RTIs; 51% and 26% reported their symptoms spontaneously or only with specific questioning, respectively. Symptoms reported spontaneously included abnormal vaginal discharge (29.3% and 22.9%, respectively). One or more RTIs, found in 70.4% of participants, included bacterial vaginosis (43.7%), trichomoniasis (16.5%), vulvovaginal candidiasis (4.5%), chlamydial infection (6.8%), gonorrhoea (1.2%), syphilis seropositivity (1.7%), cervical HPV infection (4.9%), and genital warts or ulcers (2.8%). Of 715 adequate Pap smears, 7 revealed cancer, 4 high-grade squamous intra-epithelial lesions (SIL) and 15 low-grade SIL. Clinical algorithms had very low sensitivity and predictive values for cervical infection, but over half the women with symptoms of malodorous vaginal discharge, signs of abnormal vaginal discharge, or both, had bacterial vaginosis or trichomoniasis. CONCLUSION: Overall, 77% of women had symptoms indicative of RTIs, and 70% had objective evidence of one or more RTIs. Women with selected symptoms and signs of vaginal infection could benefit from standard metronidazole therapy.

Adolescent↗

PubMed2004

Toward vaccines against cervical cancer.

Cervical cancer and pre-cancerous lesions of the genital tract are a major threat to the health of women worldwide. Introduction of screening tests to detect cervical cancer precursor lesions has reduced cervical cancer rates in the developed world, but not in developing countries. Approximately 80% of the 470,000 cervical cancer cases diagnosed worldwide each year occur in developing countries. Despite advances in treatment of cervical cancer, about half of the women with the disease will die. Over the last 20 years, several lines of scientific investigation have identified oncogenic human papillomaviruses as etiological agents for cervical cancer, and have led to the development of prophylactic vaccines against this disease.

Animals↗

PubMed2003

Isolation, structural characterization, and immunological evaluation of a high-molecular-weight exopolysaccharide from Staphylococcus aureus.

Colonization of implanted medical devices by coagulase-negative staphylococci such as Staphylococcus epidermidis is mediated by the bacterial polysaccharide intercellular adhesin (PIA), a polymer of beta-(1-->6)-linked glucosamine substituted with N-acetyl and O-succinyl constituents. The icaADBC locus containing the biosynthetic genes for production of PIA has been identified in both S. epidermidis and S. aureus. Whereas it is clear that PIA is a constituent that contributes to the virulence of S. epidermidis, it is less clear what role PIA plays in infection with S. aureus. Recently, identification of a novel polysaccharide antigen from S. aureus termed poly N-succinyl beta-(1-->6)-glucosamine (PNSG) has been reported. This polymer was composed of the same glycan backbone as PIA but was reported to contain a high proportion of N-succinylation rather than acetylation. We have isolated a glucosamine-containing exopolysaccharide from the constitutive over-producing MN8m strain of S. aureus in order to prepare polysaccharide-protein conjugate vaccines. In this report we demonstrate that MN8m produced a high-molecular-weight (>300,000 Da) polymer of beta-(1-->6)-linked glucosamine containing 45-60% N-acetyl, and a small amount of O-succinyl (approx 10% mole ratio to monosaccharide units). By detailed NMR analyses of polysaccharide preparations, we show that the previous identification of N-succinyl was an analytical artifact. The exopolysaccharide we have isolated is active in in vitro hemagglutination assays and is immunogenic in mice when coupled to a protein carrier. We therefore conclude that S. aureus strain MN8m produces a polymer that is chemically and biologically closely related to the PIA produced by S. epidermidis.

Animals↗

PubMed2003

Effect of vaccine delivery system on the induction of HPV16L1-specific humoral and cell-mediated immune responses in immunized rhesus macaques.

There have been numerous studies to assess the immunogenicity of candidate therapeutic and prophylactic vaccines for human papillomavirus (HPV), but few of them have directly compared different vaccines in an immunologically relevant animal system. In the present study, several vaccine delivery systems (VLPs, chimeric VLPs, plasmid DNA, and a replication incompetent adenoviral vector) expressing HPV16L1 were evaluated for their ability to induce HPV16L1 VLP-specific humoral immune responses, including neutralizing antibodies, and cell-mediated immune responses in rhesus macaques. Monkeys immunized with HPV16L1 VLPs mounted a potent humoral response with strongly neutralizing antibodies and a strong L1-specific Th2 response as measured by IL-4 production by CD4+ T cells. Monkeys immunized with plasmid DNA or an adenoviral vector expressing HPV16L1 showed strong Th1/Tc1 responses as measured by IFN-gamma production by CD4+ and/or CD8+ T cells and potent humoral responses, but only weakly neutralizing antibodies. These data demonstrate that the nature of the immune response against HPV16L1 is dramatically different when it is introduced via different delivery systems. Additionally, these findings support the notion that an HPV16L1 VLP-based vaccine will induce the strongly neutralizing antibodies necessary for effective prophylaxis.

Adenoviridae↗

PubMed2003

DNA replicative functions of highly-expressed, codon-optimized human papillomavirus proteins E1 and E2.

Human papillomavirus (HPV) DNA replication requires functional HPV early (E) proteins E1 and E2. To determine the biological activity of HPV 16 E1 and E2 mutant proteins under consideration as vaccine candidates, we developed a sensitive real time PCR assay that monitors HPV origin-of-replication-driven DNA synthesis. The assay was used to determine the DNA replicative functions of highly-expressed, codon-optimized HPV 16 E1 and E2 wild type and mutant proteins in transient transfections. Under the assay conditions, the HPV 16 E1 mutant (W439R, G482D) did not support HPV origin-driven DNA synthesis. In contrast, however, an HPV 16 E2 mutant bearing an E39A substitution, reported previously to be severely compromised for DNA replication, was found to be reduced only two-fold in activity and, therefore, considered not sufficiently inactivated for use in vaccines that depend on endogenous protein expression.

Amino Acid Substitution↗

PubMed2003

Poor sensitivity of polymerase chain reaction assays of genital skin swabs and urine to detect HPV 6 and 11 DNA in men.

BACKGROUND: A possible reason for the failure to detect human papillomavirus (HPV) DNA in asymptomatic men who are likely to be infected is the sensitivity of the detection methods. GOAL: The goal of this study was to identify a method for sampling the anogenital skin of men that was simple and well tolerated and that would permit the detection of asymptomatic or subclinical HPV infection, which is thought to occur commonly in sexually active men. STUDY DESIGN: Swabs of genital skin and urine from men at high and low risk of infection with types 6 and 11 were tested for HPV by polymerase chain reaction. RESULTS: These specimens had a low sensitivity for HPV detection, often because inadequate material was collected on the swab. CONCLUSION: Noninvasive sampling of genital skin to identify individuals with subclinical HPV infection remains a challenge. Future studies should involve the use of more abrasive sampling devices (such as cytobrushes), perhaps combined with some type of soap to dislodge more epithelial cells.

Adult↗

PubMed2003

Evaluation of a multilocus sequence typing system for Staphylococcus epidermidis.

Staphylococcus epidermidis is a significant cause of nosocomial disease. However, the taxonomy of this pathogen, particularly at subspecies level, is unclear. A multilocus sequence typing (MLST) scheme has therefore been investigated as a tool to elucidate taxonomic relationships within this group, based on genetic relatedness. DNA sequences for internal fragments of seven housekeeping genes were compared in 47 geographically and temporally diverse S. epidermidis isolates that were obtained from clinical infections. Twenty-three different allelic profiles were detected; 17 of these were represented by single strains and the largest profile group contained 17 isolates. Diversity of the same collection of isolates was investigated by using PFGE of SmaI-digested genomic DNA to test the discrimination and validity of the MLST approach. Isolates within the largest profile group were resolved into four distinct PFGE clusters on the basis of their SmaI digest patterns. Isolates within other profile groups that contained multiple isolates had matching PFGE SmaI patterns within each group. It appears that MLST is an effective method for grouping S. epidermidis strains at the subspecies level; however, it is not as discriminatory as it has been for other species for which MLST schemes have been established and, used alone, would not be a useful method for epidemiological studies. In addition, it was demonstrated that this method was effective for confirming the identity of S. epidermidis CoNS (coagulase-negative) isolates.

Bacterial Typing Techniques↗

PubMed2003

Human papillomavirus type 6 virus-like particles present overlapping yet distinct conformational epitopes.

The epitope for a human papillomavirus (HPV) type 6 conformation-dependent, neutralizing monoclonal antibody (mAb) was partially mapped using HPV L1 recombinant virus-like particles (VLPs). The mAb H6.J54 is cross-reactive with the closely related HPV types 6 and 11. By making HPV-6-like amino acid substitutions in the cottontail rabbit papillomavirus (CRPV) major capsid protein L1, we were able to transfer H6.J54 binding activity into a CRPV/HPV-6 hybrid L1 protein. Full binding activity was achieved with only nine amino acid changes and identified a region centred on the HPV-6 residues 49-54. This region has previously been shown to be a critical part of HPV-6 type-specific epitopes. Fine mapping of the region by scanning a series of alanine substitution mutations showed that in HPV-6 VLPs this type-common epitope overlaps HPV-6 type-specific epitopes.

Amino Acid Sequence↗

PubMed2003

Real-time monitoring of bacterial infection in vivo: development of bioluminescent staphylococcal foreign-body and deep-thigh-wound mouse infection models.

Staphylococcal infections associated with catheter and prosthetic implants are difficult to eradicate and often lead to chronic infections. Development of novel antibacterial therapies requires simple, reliable, and relevant models for infection. Using bioluminescent Staphylococcus aureus, we have adapted the existing foreign-body and deep-wound mouse models of staphylococcal infection to allow real-time monitoring of the bacterial colonization of catheters or tissues. This approach also enables kinetic measurements of bacterial growth and clearance in each infected animal. Persistence of infection was observed throughout the course of the study until termination of the experiment at day 16 in a deep-wound model and day 21 in the foreign-body model, providing sufficient time to test the effects of antibacterial compounds. The usefulness of both animal models was assessed by using linezolid as a test compound and comparing bioluminescent measurements to bacterial counts. In the foreign-body model, a three-dose antibiotic regimen (2, 5, and 24 h after infection) resulted in a decrease in both luminescence and bacterial counts recovered from the implant compared to those of the mock-treated infected mice. In addition, linezolid treatment prevented the formation of subcutaneous abscesses, although it did not completely resolve the infection. In the thigh model, the same treatment regimen resulted in complete resolution of the luminescent signal, which correlated with clearance of the bacteria from the thighs.

Abscess↗

PubMed2003

Simultaneous quantitation of antibodies to neutralizing epitopes on virus-like particles for human papillomavirus types 6, 11, 16, and 18 by a multiplexed luminex assay.

Several different methods have been developed to quantitate neutralizing antibody responses to human papillomaviruses (HPVs), including in vivo neutralization assays, in vitro pseudoneutralization assays, competitive radioimmunoassays (cRIAs), and enzyme-linked immunosorbent assays. However, each of these techniques possesses one or more limitations that preclude testing large numbers of patient sera for use in natural history studies and large vaccine clinical trials. We describe here a new multiplexed assay, by using the Luminex Laboratory MultiAnalyte Profiling (LabMAP3) assay system, that can simultaneously quantitate neutralizing antibodies to human papillomavirus types 6, 11, 16, and 18 in 50 micro l of serum. The HPV-Luminex competitive immunoassay measures titers of polyclonal antibodies in serum capable of displacing phycoerythrin-labeled detection monoclonal antibodies binding to conformationally sensitive, neutralizing epitopes on the respective virus-like particles. This competitive Luminex immunoassay was found to be as sensitive, accurate, and precise as the currently used cRIAs. An effective HPV vaccine will most likely require several distinct genotypes to protect against multiple cancer causing papillomaviruses. The HPV-Luminex immunoassay should prove to be a useful tool in simultaneously quantitating antibody immune responses to multiple HPV genotypes for natural history infection studies and for monitoring the efficacy of prospective vaccines.

Adolescent↗

PubMed2002

A controlled trial of a human papillomavirus type 16 vaccine.

BACKGROUND: Approximately 20 percent of adults become infected with human papillomavirus type 16 (HPV-16). Although most infections are benign, some progress to anogenital cancer. A vaccine that reduces the incidence of HPV-16 infection may provide important public health benefits. METHODS: In this double-blind study, we randomly assigned 2392 young women (defined as females 16 to 23 years of age) to receive three doses of placebo or HPV-16 virus-like-particle vaccine (40 microg per dose), given at day 0, month 2, and month 6. Genital samples to test for HPV-16 DNA were obtained at enrollment, one month after the third vaccination, and every six months thereafter. Women were referred for colposcopy according to a protocol. Biopsy tissue was evaluated for cervical intraepithelial neoplasia and analyzed for HPV-16 DNA with use of the polymerase chain reaction. The primary end point was persistent HPV-16 infection, defined as the detection of HPV-16 DNA in samples obtained at two or more visits. The primary analysis was limited to women who were negative for HPV-16 DNA and HPV-16 antibodies at enrollment and HPV-16 DNA at month 7. RESULTS: The women were followed for a median of 17.4 months after completing the vaccination regimen. The incidence of persistent HPV-16 infection was 3.8 per 100 woman-years at risk in the placebo group and 0 per 100 woman-years at risk in the vaccine group (100 percent efficacy; 95 percent confidence interval, 90 to 100; P<0.001). All nine cases of HPV-16-related cervical intraepithelial neoplasia occurred among the placebo recipients. CONCLUSIONS: Administration of this HPV-16 vaccine reduced the incidence of both HPV-16 infection and HPV-16-related cervical intraepithelial neoplasia. Immunizing HPV-16-negative women may eventually reduce the incidence of cervical cancer.

Adolescent↗

PubMed2002

Evaluation of antibodies to human papillomavirus as prognostic markers in cervical cancer patients.

OBJECTIVES: We wished to evaluate whether the presence of antibodies to HPV or to the HPV oncoproteins E6 and E7 or type of HPV DNA is related to prognosis among cervical cancer patients. METHODS: Blood samples were drawn from 313 patients with incident, untreated cervical cancer on admission to two hospitals in Sweden. Patients were followed from enrollment in 1984-1991 until death or up to June 1999. Clinical information was obtained from a review of medical records. Survival and cause of death were ascertained from both medical records and population-based cancer registries. The correlation of survival with antibodies to HPV16, to oncoproteins E6 and E7, and to type of HPV DNA was evaluated using multivariate Cox regression analysis, including stage, age, histology, and hospital in the model. RESULTS: Stage was the only significant prognostic factor influencing cervical cancer patient survival (OR = 3.62, 95% CI = 2.71-4.83). Age over 50 was associated with increased death rate among stage I-IIa patients (OR = 2.29, 95% CI = 1.12-4.68). Presence of antibodies to the oncoproteins E6 and E7 or to the HPV16 capsid or type of HPV DNA did not associate significantly with disease prognosis. CONCLUSIONS: Antibodies to HPV16 capsids and to oncoproteins E6 and E7 or type of HPV DNA do not appear to be useful as indicators of cervical cancer prognosis.

Adenocarcinoma↗

PubMed2002

Infectious virions produced from a human papillomavirus type 18/16 genomic DNA chimera.

The organotypic raft culture system has allowed the study of the differentiation-dependent aspects of the human papillomavirus (HPV) life cycle. However, genetic strategies to more completely understand the HPV life cycle are limited. The generation of chimeric viruses has been a useful tool in other virus systems to analyze infection and replication. To investigate the specificity of the interaction of nonstructural genes of one HPV type with the structural genes of another HPV type, we have replaced the L2 and L1 open reading frames (ORFs) of HPV type 18 (HPV18) with the L2 and L1 ORFs of HPV type 16 (HPV16). The resulting HPV18/16 chimeric construct was introduced into primary keratinocytes, where it was stably maintained episomally at a range of 50 to 100 copies of HPV genomic DNA, similar to that typically found in HPV-infected cells in vivo. The integrity of the HPV18/16 genomic DNA chimera was demonstrated. Upon differentiation in raft cultures, late viral functions, including viral DNA amplification, capsid gene expression, and virion morphogenesis, occurred. Chimeric HPV18/16 virions were purified from the raft cultures and were capable of infecting keratinocytes in vitro. Additionally, infection was specifically neutralized with human HPV16 virus-like particle (VLP)-specific antiserum and not with human HPV18 VLP-specific antiserum. Our data demonstrate that the nonstructural genes of HPV18 functionally interact with the structural genes of HPV16, allowing the complete HPV life cycle to occur. We believe that this is the first report of the propagation of chimeric HPV by normal life cycle pathways.

Animals↗

PubMed2002

Priming of human papillomavirus type 11-specific humoral and cellular immune responses in college-aged women with a virus-like particle vaccine.

In this study, we evaluated the potency of a human papillomavirus (HPV) virus-like particle (VLP)-based vaccine at generating HPV type 11 (HPV-11)-specific cellular and humoral immune responses in seronegative women. The vaccine was administered by intramuscular immunizations at months 0, 2, and 6. A fourth immunization was administered to approximately half of the women at month 12. All vaccine recipients had positive HPV-11 VLP-specific lymphoproliferative responses at month 3 following the second immunization (geometric mean lymphoproliferative stimulation index [SI] = 28.4; 95% confidence interval [CI] = 16.9 to 48.0) and HPV-11 VLP-specific antibody titers following the first immunization at month 1 (geometric mean antibody titer = 53.9 milli-Merck units/ml, 95% CI, 34.8 to 83.7). In contrast, lymphoproliferative and antibody titer responses were never detected in the participants who received placebo. Relatively homogeneous lymphoproliferative responses were observed in all vaccinated women. The mean lymphoproliferative SI of the vaccinated group over the first 12 months of the study was 7.6-fold greater than that of the placebo group following the initial immunization. The cellular immune responses generated by VLP immunization were both Th1 and Th2, since peripheral blood mononuclear cells from vaccinees, but not placebo recipients, secreted interleukin 2 (IL-2), IL-5, and gamma interferon (IFN-gamma) in response to in vitro stimulation with HPV-11 VLP. The proliferation-based SI was moderately correlated with IFN-gamma production and significantly correlated with IL-2 production after the third immunization (P = 0.078 and 0.002, respectively). The robust lymphoproliferative responses were specific for HPV-11, since SIs generated against bovine papillomavirus and HPV-16 VLPs were not generally observed and when detected were similar pre- and postimmunization.

Adolescent↗