Search PubMed⌕ Search

Biomedical subjects

R Arndt

Publications and source records attributed to R Arndt.

At least 19 recordsLinked to original sources
PubMed2002

HHV-8 DNA in blood and the development of HIV-associated Kaposi's sarcoma in the era of HAART--a prospective evaluation.

OBJECTIVE: To explore the significance of HHV-8 viremia in HIV-positive individuals for the risk of developing Kaposi's sarcoma (KS) in the era of highly active antiretroviral therapy. METHODS: 237 HIV-positive patients were included in this prospective evaluation and followed over an average duration of 34 months. HHV-8 DNA in peripheral blood mononuclear cells (PBMCs) and CD4-lymphocytes were determined. In addition AIDS-defining conditions and antiretroviral therapy were documented of all participating subjects. RESULTS: HHV-8 DNA was detectable in PBMCs of 12.6% out of all individuals. 53.3% of these patients initially complained about KS, although 9.2% of patients without HHV-8 DNA in PBMCs were found on KS as well. Furthermore, four patients in total were observed with newly developed KS during follow up visits. None of these patients were noted with detectable HHV-8 DNA at their initial evaluation. CONCLUSIONS: Prevalence of HHV-8 DNA in PBMCs of subjects in this investigation was quite similar to former investigations. However, new diagnosed KS occurred less frequently than demonstrated in previous studies. All of those observed patients with new KS manifestations were negative for HHV-8 DNA in PBMCs at study entry. This observation differs from earlier studies which have postulated the detection of HHV-8 DNA in PBMCs as a predictive value for development of KS. Due to results as presented, a single HHV-8 DNA test in blood has no predictive value in support of predictability of KS development. With respect toto costs and to a less complicated performance antibody assays should be preferred.

Adult↗
PubMed2002

Monitoring of endogenous interferon-alpha and human herpesvirus 8 in HIV-infected patients with Kaposi's sarcoma.

The incidence of AIDS-associated Kaposi's sarcoma has declined since the mid-nineties due to the availability of potent antiretroviral therapy including protease inhibitors. However, Kaposi's sarcoma is still the most common neoplasia in HIV-infected patients. In the pathogenesis of the HIV-associated as well as other forms of this disease an infectious agent seems to play a role, namely the human herpesvirus 8. Even before the discovery of the HIV virus, high levels of an unusual acid-labile form of endogenous interferon alpha were found in patients with AIDS-associated KS. The administration of recombinant interferon alpha evolved as standard therapy for Kaposi's sarcoma in HIV-infected patients with a moderate immunodeficiency in addition to antiretroviral therapy. This investigation monitored the levels of HHV 8 and endogenous interferon in 4 patients with and without Kaposi's sarcoma during the course of HIV-disease. The results of our experiments lead us to two hypotheses: First of all, the pre-therapeutic level of endogenous interferon may be a predictor of the response to an interferon-alpha therapy for HIV-associated Kaposi's sarcoma. Secondly, the determination of HHV 8 DNA in blood of HIV-positive patients may allow conclusions about the risk for the development of Kaposi's sarcoma. However these hypotheses should be tested by monitoring the levels of endogenous interferon and HHV 8 DNA in clinical studies of a greater number of HIV-infected patients.

Adult↗
PubMed2002

Clinical evaluation of 5-S-cysteinyldopa testing using a new and optimized detection system as a tumour marker for malignant melanoma.

5-S-cysteinyldopa (5-S-CD) has been described as a tumour marker for the detection of human metastatic melanoma. We investigated the clinical utility of a new and optimized method to detect 5-S-CD by analysing 207 plasma samples derived from 138 patients with clinical stage I/II ( = 60), III ( = 32) or IV ( = 46) melanoma. Control groups consisted of 27 patients with non-melanoma skin diseases and 30 healthy volunteers. 5-S-CD plasma levels were determined using a new analytical technique based on a fully automated solid phase extraction coupled online to a novel high performance liquid chromatography method. In all the samples from the healthy control subjects 5-S-CD plasma concentrations were below 2.0 microg/l. Increased 5-S-CD-levels (>/=2.0 microg/l) were found in 52%, 67% and 81% of the plasma samples from patients with stages I/II, III and IV malignant melanoma, respectively. The mean values of 5-S-CD were found to rise with increasing tumour stage. Among 27 samples from patients with non-melanoma skin disease, slightly elevated 5-S-CD levels between 2.3 and 2.6 microg/l were found in only four samples from patients with multiple dysplastic naevi. In conclusion, our improved analytical technique provides a high sensitivity in all stages of the disease and represents a useful technique for monitoring melanoma patients.

Biomarkers, Tumor↗
PubMed2001

Cysteine and indole derivatives as markers for malignant melanoma.

Malignant melanoma is a skin tumour, which carries a very unfavourable prognosis. The early detection of a melanoma and even more its metastasis is of decisive importance for the survival prognosis of the patients. So there is always a desire for simple, economical and meaningful serological markers. From the cysteine- and indole-related derivatives, 5-S-cysteinyldopa (5-SCD) and 6-hydroxy-5-methoxy-indole-2-carboxylic acid (6H5MI2C) are the most important substances for this purpose. For 5-SCD, the sample pretreatment was carried out either by a manual extraction onto alumina, by an automated method onto boronic acid affinity gels or by an automated solid-phase extraction. For 6H5MI2C, liquid-liquid extractions or direct injection techniques were applied. The chromatographic analyses in the early years were mostly performed with GC-MS. Today HPLC is the nearly exclusively used separation technique. For HPLC, standard RP18 separating columns and usual compositions of eluents were applied. As detectors both the ECD and the FD showed a sufficient sensitivity and selectivity. 5-SCD and 6H5MI2C are very sensitive to light and oxidation. These properties must be taken into account in the complete analysis procedure, including the sample collection, otherwise false low values will result especially for plasma samples. For a critical discussion of the analytical methods and still more for the interpretation of the obtained results, the detailed analytical procedures must be considered. 5-SCD in plasma is one of the best markers of malignant melanoma. It shows an excellent specificity and also an adequate sensitivity in the metastatic melanoma stages. For the detection of primary melanomas and for urine instead of plasma samples, the sensitivity of 5-SCD is generally lower. Altogether, the sensitivity of this parameter is not yet sufficient. 6H5MI2C and other indole derivatives have been investigated far less than 5-SCD. 6H5MI2C correlates less clearly with the different stages of the melanoma and is therefore a less suitable marker. To improve the sensitivity of the findings, in future the investigations should be performed as multi-marker analysis with the simultaneous measurements of more than one marker substance in a given patient sample. Not only one measurement should be carried out per patient, it would be more meaningful to observe the patients with laboratory diagnostics in the follow-up.

Biomarkers, Tumor↗
PubMed2001

Resistance analyses in HIV infected patients with a history of multiple antiretroviral treatment regimens.

OBJECTIVE: To assess HIV-1 isolate based resistance profiles from extensively pretreated patients and effects of a resistance guided switch of antiretroviral therapy. METHODS: In a prospective study phenotypic and genotypic resistance analyses were performed on HIV infected individuals with failure of the current therapy and history of at least three antiretroviral regimens. Antiretroviral therapy was changed according to the results. Viral load and CD4 lymphocyte counts were measured at baseline, after 10 (SD 2), and 24 (2) weeks. RESULTS: All patients (n=52) failed their actual regimen. Currently versus ever previously taking the specific drug, resistance associated mutations and phenotypic resistance to AZT and 3TC were found in over 80% of individuals; resistance to DDI and D4T was detected in less than 10% of cases. A resistance guided switch of therapy was followed by a median decrease of viral load of 0.5 log10 units after 24 weeks. Individuals resistant to two or more drugs compared with patients with resistance to less than two drugs of ongoing treatment, were switched to a regimen containing DDI, D4T, and a PI or NNRTI. After 10 (SD 2) weeks viral load decrease was pronounced in patients with resistance to at least two drugs in the previous regimen. CONCLUSIONS: Among different RTI, the profile of clinically relevant resistance indicates pronounced differences when looking at separate drugs. Regarding virological response, in the context of available drugs, resistance tested with currently used methods is of limited value in extensively pretreated patients and seems to have its value primarily in first or second switch of therapy.

Adult↗
PubMed2001

Importance of human papillomaviruses for the development of skin cancer.

The frequent detection of HPV DNA in non-melanoma skin cancers was shown in several studies; however, the role of HPV in the development of these cancers remains speculative. We analyzed different skin tumors, normal skin, and hair follicles for HPV DNA using a PCR system designed to detect all HPV types known so far. HPV DNA was found in 93% of common warts, 69% of squamous cell carcinomas (SCC), 52% of basal cell carcinomas (BCC), 41% of actinic keratoses, 31% of extragenital Bowen's disease, 22% of keratoacanthomas, 16% of normal skin tissues and 47% of hair follicles. No individual HPV type predominated in any of the skin tumors. The number of HPV genomes in individual neoplasms (SCC and BCC) seems to be less than I per cancer cell. These results indicate that a direct role of HPV in skin cancerogenesis remains questionable. Possibly, mechanisms different from the activity of HPV oncoproteins in genital cancers are involved in skin neoplastic transformation.

Adolescent↗
PubMed2000

Patients with bullous pemphigoid and linear IgA disease show a dual IgA and IgG autoimmune response to BP180.

Bullous pemphigoid (BP) and linear IgA disease (LAD) are autoimmune subepidermal blistering skin diseases associated with autoantibodies against the transmembrane hemidesmosomal protein BP180/type XVII collagen. It has been demonstrated previously that BP is characterized predominantly by IgG autoantibodies, while autoantibodies in LAD mainly belong to the IgA isotype. The aim of the present study was to investigate the hypothesis that there is a significant overlap in the autoantibody isotype profiles associated with these two diseases. Several new recombinant forms of BP180 were generated in the baculovirus expression system, including the full-length protein. IgG autoantibodies to BP 180 were detectable in 39 of 40 (98%) of BP sera; interestingly, 88% of BP sera also contained IgA anti-BP180 autoantibodies. Similarly, anti-BP180 reactivity in LAD sera (n=22) was also attributed to both an IgA (68%) and an IgG (76%) autoantibody response. IgA and IgG autoantibodies to the intracellular portion of BP180 were found in 14% and 28% of BP sera, respectively, and in 8% of LAD sera (same percentage for both isotypes). Our findings clearly demonstrate that both BP and LAD patients have a dual IgA and IgG autoimmune response to BP180 which is directed not only to the ectodomain, but also to the intracellular portion of this protein.

Adult↗
PubMed2000

Detection of human papillomavirus and response to topical 5% imiquimod in a case of stucco keratosis.

Stucco keratosis is a skin disorder with papular warty lesions that usually appear on the lower limbs in elderly people. The aetiology, pathogenesis and treatment is still a matter of debate. We report a 75-year-old non-immunosuppressed man with extensive lesions all over his body, which had not responded to curettage or electrodesiccation. To determine the possible role of human papillomavirus (HPV) in stucco keratosis, we used nested polymerase chain reaction (PCR) to identify HPV DNA in the lesions. To include a broad range of both cutaneous and mucosal HPV types, PCR was performed with two sets of degenerate primers. Using this approach we detected HPV types 9, 16, 23b, DL322 and a variant of HPV type 37 in multiple stucco keratoses. Imiquimod (5% cream), a new compound that modifies the immune response by stimulating production of cytokines, applied overnight, three times a week for 5 weeks, resulted in resolution of all treated lesions.

Aged↗
PubMed2000

Frequency and spectrum of HPV types detected in cutaneous squamous-cell carcinomas depend on the HPV detection system: a comparison of four PCR assays.

BACKGROUND: The association of human papillomavirus (HPV) with cutaneous squamous-cell carcinomas (SCCs) has been described recently, but the frequency and spectrum of HPV types identified differed substantially in distinct studies. OBJECTIVE: Comparison of different PCR assays with respect to sensitivity and range of HPV types detected. METHOD: Cutaneous SCC were analyzed for HPV DNA using both consensus PCR assays with degenerate primers and PCR assays with nondegenerate primers derived from HPV types 5 and 8. RESULTS: HPV DNA was found in 50% of SCC specimens using degenerate primers. The rate of HPV-DNA-positive specimens increased to 69% when PCR assays with nondegenerate primers were applied in addition. The spectrum of HPV types detected with each of the PCR assays differed considerably. CONCLUSIONS: The frequency and spectrum of HPV types detected in cutaneous SCC strongly depends on the HPV detection system used and urges the need for standardization of HPV detection and typing in skin lesions in order to characterize HPV types predominating in distinct tumors.

Aged↗
PubMed2000

Falsely increased HbA1c values by HPLC and falsely decreased values by immunoassay lead to identification of Hb Okayama and help in the management of a diabetic patient.

A falsely increased HbA1c value of 47.1% was determined by cation exchange chromatography during a routine HbA1c measurement of the blood sample from a 63-year-old diabetic male patient living in Hamburg, Germany. In former determinations by immunological assays falsely decreased values in the range of 5.0 to 5.5% were obtained. The sample was inconspicuous in alkaline hemoglobin electrophoresis. But acid hemoglobin electrophoresis confirmed the falsely increased value. These facts let us consider the existence of a heterozygous "silent hemoglobin variant", such as hemoglobin Okayama, with an amino acid substitution in one of the first four amino acids of the beta chain, representing the epitope of common immunoassays. DNA analyses confirmed this presumption and we found the heterozygous mutation hemoglobin Okayama [beta 2 (NA 2) His (CAC)-->Gln (CAA)]. Knowing that an immunological assay only detects about half of the present HbA1c, the obtained values can be used for therapeutic management of this diabetic patient.

Amino Acid Substitution↗
PubMed1999

Determination of 5-S-cysteinyldopa in plasma and urine using a fully automated solid-phase extraction--high-performance liquid chromatographic method for an improvement of specificity and sensitivity of this prognostic marker of malignant melanoma.

5-S-Cysteinyldopa (5-SCD) in plasma and urine was determined by means of a newly developed method. This method incorporates optimized conditions for blood collection and storage, as well as a new extraction and separation technique, required for the strong oxidation and light sensitive 5-SCD. The new aspects of the method are the following: immediate centrifugation and freezing of the samples after blood collection, fully automatical solid-phase extraction (SPE) with phenylboronic acid (PBA) cartridges and immediate HPLC injection of the eluate, nearly complete exclusion of light and air-oxygen during extraction, constant sample cooling, use of the more suitable internal standard 5-S-D-cysteinyldopa and easy, sensitive and selective HPLC conditions (RP18-column with isocratic separation and electrochemical detection). The method has a linear range from 0.25 to 50 microg l(-1) and 25 to 5000 microg l(-1) for plasma and urine samples, respectively, a limit of detection of 0.17 microg l(-1), intra-assay variabilities from 1.7 to 3.6%, inter-assay variabilities from 4.0 to 18.3% and an average relative recovery of 103.5% for plasma and 105.4% for urine samples. In our study the measured 5-SCD concentrations of patients with melanomas at various stages correlated better with their clinical pictures than described in literature up to date. The results were obtained in comparison to patients with other skin tumors and in comparison to healthy control persons.

Automation↗
PubMed1999

Identification of DNA sequences of both genital and cutaneous HPV types in a small number of keratoacanthomas of nonimmunosuppressed patients.

BACKGROUND: Viral infection was suggested to be etiologically involved in skin tumor development. Data on the association of human papillomavirus (HPV) with keratoacanthomas are still conflicting. OBJECTIVE: Analysis of HPV infection in keratoacanthomas of the general population. METHODS: HPV DNA was detected by nested PCR. To include a broad range of both cutaneous and mucosal HPV types, HPV PCR was performed with two sets of degenerate primers. RESULTS: Considering only beta-globin-positive specimens, HPV DNA was detected in 20% of the specimens obtained from 18% of the patients. The spectrum of HPV types detected contains HPV types 6, 14, 16, 35, 58 and 61. In 1 case, the underlying HPV type was not identified. In 1 specimen with transition towards squamous-cell carcinoma, HPV 16 was detected. CONCLUSIONS: HPV is probably not generally associated with the etiology of keratoacanthoma but may be relevant in individual cases. Oncogenic HPV types may be cofactors for malignant transformation of initially benign skin lesions like keratoacanthomas.

DNA, Viral↗
PubMed1999

p53 autoantibodies in patients with autoimmune diseases: a quantitative approach.

With few exceptions, autoantibodies directed against the gene product of the tumor suppressor gene p53 are only detected in cancer patients. From 73 patients with various autoimmune diseases, we obtained 17 sera with elevated autoantibodies against the p53 protein comprising patients with SLE, Graves' disease, and immune vasculitis including Wegener's granulomatosis. The overall prevalence (23%) of p53 autoantibodies was comparable to that in various cancers; differences, however, were obvious with respect to the magnitude of antibody levels. Only 5% of seropositive colorectal cancer patients had levels within the critical range (150-180 U/ml) but nearly half (41%) of seropositive autoimmune disease patients were that low. None of the autoimmune disease patients exceeded 300 U/ml serum compared to more than 60% of seropositive colorectal cancer patients with higher levels. This remarkable difference in magnitude underlines the necessity of quantification of p53 autoantibodies over a mere qualitative determination. Patients with autoimmune diseases face an increased risk for malignancies. It still remains to be established whether p53 seropositivity in autoimmune diseases adds to the rare exceptions of p53AAb in non-malignant diseases or is indicative for a yet occult cancer.

Autoantibodies↗
PubMed1998

Association of rare human papillomavirus types with genital premalignant and malignant lesions.

Due to the limited number of reports concerning their association with particular dysplastic and neoplastic lesions, the oncogenic potential of so-called rare or novel human papillomavirus (HPV) types is still unclear. Cytologic smears or biopsy specimens from 538 patients were analyzed for dysplastic or neoplastic lesions and HPV infection. The HPV detection and typing system utilized allowed identification of all mucosal HPVs amplifiable by L1 polymerase chain reaction. Considering only patients infected with a single HPV type (n = 329), rare or novel HPVs (HPV-59, HPV-61, HPV-62, HPV-66, HPV-70, HPV-73, MM4, MM7, MM8, CP6108, and CP8304) were detected in 28% of normal specimens (n = 46), none of condylomatous lesions (n = 44), 12% of low-grade squamous intraepithelial lesions (SILs) (n = 42), 8% of high-grade SILs (n = 142), and 4% of cervical cancers (n = 54). Prevalence and oncogenic potential of distinct rare HPV types seems to be higher than previously assumed.

Condylomata Acuminata↗