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Biomedical subjects

P Emmerich

Publications and source records attributed to P Emmerich.

At least 19 recordsLinked to original sources
PubMed2002

Preliminary approach to elucidate the role of pigment as a binding site for drugs and chemicals in anagen hair: differential uptake of 3H-haloperidol by pigment-producing compared to non-pigment-producing cell lines.

A striking difference was observed for cellular-bound drug in HaCaT and Sk-Mel-1 cells for a fixed drug exposure time of 72 h and varying 3H-haloperidol concentrations in the culture media. Drug uptake was dependent on drug concentration and linearly correlated for both the non-pigment- and the pigment-producing cells which however was different in magnitude. In an additional investigation the time course of drug uptake during 3H-haloperidol exposure (400 pmol/ml; 28 days) revealed increasing drug concentrations in the Sk-Mel-1 population, whereas drug concentrations in the keratinocytes reached a plateau within a short time period. In contrast to the HaCaT cells no tendency to saturation was observed for the pigment-producing cell line. At the end of the experiments 3H-haloperidol concentrations in Sk-Mel-1 were found to be approximately tenfold higher than in HaCaT.

Binding Sites↗
PubMed2002

Preliminary approach to elucidate the role of pigment as a binding site for drugs and chemicals in anagen hairs: pigments as carriers for 3H-haloperidol in HaCaT/Sk-Mel-1 co-cultures.

In view of the melanin-binding characteristics of haloperidol and its differential uptake by pigment- and non-pigment-producing cells, a co-culture of HaCaT with Sk-Mel-1 cell lines was performed to investigate whether melanosomes act as carriers for drug molecules associated with the pigments. Initially, HaCaT and Sk-Mel-1 cells were separately cultivated in the presence of 3H-haloperidol (400 pmol/ml medium ) for 28 days followed by subsequent co-cultivation in the absence of 3H-haloperidol for 5 days. The transfer of pigments into the keratinocytes during co-culture was confirmed by transmission electron microscopy. After the co-culture experiments a striking increase (> or = 50%) of 3H-haloperidol was observed in the pigmented HaCaT cells compared to the unpigmented keratinocytes. The present study proved the role of pigments as carriers for melanin-associated drug molecules. The results supported the hypothesis that hair pigment might be a factor affecting the outcome of hair assays for particular categories of commonly used licit and illicit substances. The chosen cell lines and the developed co-culture system may represent suitable in vitro models to study differential drug uptake into cell populations present in the skin or in the growing hair follicle as well as to elucidate drug uptake due to melanocyte-keratinocyte interactions.

Binding Sites↗
PubMed2002

Cross-reactivity in flavivirus serology: new implications of an old finding?

To investigate the influence of pre-existing antibodies against tick-borne encephalitis (TBE) or yellow fever (YF) viruses on dengue virus antibody test results, we examined sera from vaccinees and from individuals with previous TBE virus infection. Distinct IgG antibody cross-reactivity was found in about 15.1% in the YF-vaccinated group and in about 9.5% in the TBE-vaccinated group. Altogether 15 out of a total of 80 samples tested (18.8%) had detectable dengue virus IgG antibody titres. The serum samples from patients with acute TBE virus infection not only had the highest anti-TBE virus antibodies but were also highly cross-reactive against dengue virus antigens. The high cross-reactivity rate of YF and TBE antibody-positive sera in dengue virus antibody assays should be taken into account in the interpretation of laboratory tests for the diagnosis of flavivirus infections and when undertaking seroepidemiological surveys.

Antibodies, Viral↗
PubMed2001

Lassa fever encephalopathy: Lassa virus in cerebrospinal fluid but not in serum.

The pathogenesis of neurologic complications of Lassa fever is poorly understood. A Nigerian patient had fever, disorientation, seizures, and blood-brain barrier dysfunction, and Lassa virus was found in cerebrospinal fluid (CSF) but not in serum. The concentration of Lassa virus RNA in CSF corresponded to 1 x 10(3) pfu/mL, as determined by a quantitative real-time polymerase chain reaction assay. To characterize the Lassa virus in CSF, the 3.5-kb S RNA was sequenced. In the S RNA coding sequences, the CSF strain differed between 20% and 24.6% from all known prototype strains. These data suggest that Lassa virus or specific Lassa virus strains can persist in the central nervous system and thus contribute to neuropathogenesis. Lassa virus infection should be considered in West African patients or in travelers returning from this area who present only with fever and neurologic signs.

Amino Acid Sequence↗
PubMed2001

Antibodies to Lassa virus Z protein and nucleoprotein co-occur in human sera from Lassa fever endemic regions.

It is not known whether the small 11-kDa Z protein of Lassa virus is immunogenic during human Lassa virus infection. To obtain evidence for the existence of an antibody response and to test the suitability of these antibodies for serosurveys, sera from Lassa fever endemic regions (Guinea and Nigeria, n = 75) were tested for co-reactivity to Z protein and nucleoprotein (NP). Sera from a non-endemic region (Uganda, n = 50) served as a specificity control. Z protein and NP were expressed in Escherichia coli, affinity-purified, and used as antigen in Western blot. Indirect immunofluorescence (IIF) with Lassa virus-infected cells was performed for comparison. Due to high unspecific reactivity of the African sera, Western blot testing was performed with a 1:1,000 serum dilution. Under these conditions, none of the control sera but 12% of the sera from endemic regions co-reacted with both Z protein and NP. Reactivity to Z protein was significantly associated with NP reactivity (P < 10(-6)). NP and Z protein-specific antibodies were co-detected in 33% of the IIF-positive sera and in 5% of the IIF-negative sera (P = 0.001). These data provide evidence for appearance of antibodies to Z protein and NP following Lassa virus infection. A recombinant blot for detection of both antibody specificities seems to be specific but less sensitive than IIF.

Antibodies, Viral↗
PubMed2000

Isolation and partial characterization of dengue virus type 2 and 4 strains from dengue fever and dengue haemorrhagic fever patients from Mindanao, Republic of the Philippines.

OBJECTIVE: Isolation of dengue virus from dengue fever and dengue haemorrhagic fever cases from Mindanao, Republic of the Philippines. METHODS: 12 patients with clinically suspected dengue fever (DF) or dengue haemorrhagic fever (DHF) presenting in four regional hospitals between August and September 1995 on Minadano were enrolled in the study. Dengue virus was isolated by inoculation of Vero/E6 or C6/36 cells with patient serum. IgM antibodies were measured using a commercial test system. Up to 454 bp of the capsid region and 240 bp of the E/NS1 gene junction of different viral isolates were sequenced and phylogenetically analyzed. RESULTS: Virus could be isolated from seven patients, five isolates were typed as dengue virus type 2 and two as dengue virus type 4 by immunostaining with monoclonal antibodies or by RT/PCR. Phylogenetic analysis confirmed a close relationship of the dengue virus type 2 isolates with viruses isolated in the Philippines in 1983 and 1988. CONCLUSION: As observed in studies from other parts of South East Asia, dengue virus type 2 was readily isolated from dengue haemorrhagic fever cases. Dengue virus type 2 and 4 circulate in Mindanao, Philippines, with dengue type 2 being responsible for most of our severe DF or DHF cases.

Child↗
PubMed1999

Assessment of IgG antibodies against yellow fever virus after vaccination with 17D by different assays: neutralization test, haemagglutination inhibition test, immunofluorescence assay and ELISA.

We analysed serum samples of 209 subjects immunized with yellow fever vaccine 17D by different assays: neutralization test, immunofluorescence assay, haemagglutination inhibition test and ELISA, for presence of 17D-specific antibodies. Serum samples were taken from a few weeks up to 35 years after vaccination. The neutralization test had the highest sensitivity. There was no correlation of results between the serological assays. Considering NT titres > 1:10 as indicating protection, we found that about 75% of subjects remained immune even 10 years after vaccination, with a median NT titre of 1:40 in reactive sera.

Adolescent↗
PubMed1999

Detection of dengue virus RNA in patients after primary or secondary dengue infection by using the TaqMan automated amplification system.

In consecutive serum samples from 25 tourists with acute dengue fever, virus-specific RNA was detected by using fully automated TaqMan reverse transcriptase PCR. For this amplification technique new primers and special fluorochrome-labeled probes had to be synthesized. During amplification the increasing amount of viral DNA could simultaneously be measured in the tightly sealed tubes. Dengue virus RNA was found in almost all patients (17 of 18), if the samples had been taken soon after the onset of symptoms and before anti-dengue virus antibody had been produced. RNA was detectable in only one of five persons who had anti-dengue virus immunoglobulin M (IgM) antibodies but not yet IgG antibodies. In 30 late samples with both IgG and IgM antibodies viral RNA was no longer demonstrable. In two early samples from two frequent travelers obtained 1 and 2 days after the onset of symptoms significant IgG antibody titers were present but there were no anti-dengue virus IgM antibodies. In these samples a viral load of >5 x 10(6) dengue virus RNA copies (dengue types 1 and 2) was detectable. These findings of a high viral load in the presence of anti-dengue virus IgG antibody are suggestive of a secondary dengue virus infection. In the 20 tourists (17 plus 1 plus 2) in whom viral RNA was found, the dengue virus serotype could be related to the area where the infection had taken place. Most of our patients came from southeast Asia and most frequently had dengue virus type 1 infections (8 of 20).

Base Sequence↗
PubMed1999

De novo deletion (14)(q11.2q13) including PAX9: clinical and molecular findings.

A 3 year old boy with a de novo deletion (14)(q11.2q13) of paternal origin encompassing the region from D14S264 to D14S70 is described. The patient presented with severe psychomotor retardation, bilateral cleft lip/palate, bilateral colobomas of the optic nerves and retinas, agenesis of the corpus callosum, pes calcaneovarus, reduced oesophageal peristalsis, and swallowing difficulties. This is the first reported case of PAX9 hemizygosity in humans. Haploinsufficiency of the PAX9 gene might be expected to cause some of the developmental defects and the dysphagia. Another haploinsufficiency candidate gene, the bZIP transcription factor gene NRL, which is specifically expressed in neuronal cells and the eye during embryogenesis, was excluded from the deletion interval.

Abnormalities, Multiple↗
PubMed1996

Imported tropical virus infections in Germany.

Our routine tests for tropical viruses document that several hundreds of Dengue fever cases are imported into Germany every year. In contrast, hemorrhagic fever cases are rarely diagnosed in Germany. Our investigations suggest that this low number is due to the different living conditions of the local population in the tropics compared with that of travellers from Europe or North America. Improved methods for detecting Dengue virus infections, e.g. three different antibody tests and the reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of viral RNA, have been developed.

Animals↗
PubMed1993

Chimeric human and mouse spheroids.

We investigated structures resembling embryoid bodies (EBs), grown intraperitoneally in nude mice after the injection of xenografted human teratocarcinoma cells. Following in situ hybridization of paraffin sections containing these EB-like structures with either human or mouse total genomic DNA, two species-specific types of cell nuclei were localized. Tumor cells of human origin were found centrally but flattened normal mouse cells formed an outer coat. Thus these spheric structures are of bispecies origin and do not meet the definition of EBs. For a clear distinction from EBs and spheroids, we termed these structures chimeric spheroids.

Animals↗
PubMed1992

Chromosomal in situ suppression hybridization of immunologically classified mitotic cells in hematologic malignancies.

Chromosomal in situ suppression (CISS) hybridization was performed with library DNA from sorted human chromosomes 8, 9, 15, 17, 21, and 22 on immunologically stained bone marrow cells of four patients with a hematologic neoplasm, including two patients with myelodysplastic syndrome and trisomy 8, one patient with promyelocytic leukemia bearing the translocation t(15;17)(q22;q11-12), and one patient with chronic myeloid leukemia and the translocation t(9;22)(q34;q11). In all patients, the results of conventional karyotype analysis could be confirmed by one- or two-color CISS hybridization using the appropriate chromosome-specific libraries. Our results show that CISS hybridization can detect both numerical and structural chromosome changes in immunologically classified cells with high specificity and reliability. The fact that chromosome spreads of very poor quality can now be included in such analyses is a decisive advantage of this approach. In addition, the suitability of this approach for interphase cytogenetics is discussed.

Chromosome Aberrations↗
PubMed1990

Rapid metaphase and interphase detection of radiation-induced chromosome aberrations in human lymphocytes by chromosomal suppression in situ hybridization.

Chromosomal in situ suppression (CISS)-hybridization of biotinylated phage DNA-library inserts from sorted human chromosomes was used to decorate chromosomes 1 and 7 specifically from pter to qter and to detect structural aberrations of these chromosomes in irradiated human peripheral lymphocytes. In addition, probe pUC1.77 was used to mark the 1q12 subregion in normal and aberrant chromosomes 1. Low LET radiation (60Co-gamma-rays; 1.17 and 1.33 MeV) of lymphocyte cultures was performed with various doses (D = 0, 2, 4, 8 Gy) 5 h after stimulation with phytohaemagglutinin. Irradiated cells were cultivated for an additional 67 h before Colcemid arrested metaphase spreads were obtained. Aberrations of the specifically stained chromosomes, such as deletions, dicentrics, and rings, were readily scored after in situ hybridization with either the 1q12 specific probe or DNA-library inserts. By the latter approach, translocations of the specifically stained chromosomes could also be reliably assessed. A linear increase of the percentage of specifically stained aberrant chromosomes was observed when plotted as a function of the square of the dose D. A particular advantage of this new approach is provided by the possibility to delineate numerical and structural chromosome aberrations directly in interphase nuclei. These results indicate that cytogenetic monitoring of ionizing radiation may be considerably facilitated by CISS-hybridization.

Chromosome Aberrations↗