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Biomedical subjects

J Gerdes

Publications and source records attributed to J Gerdes.

At least 55 records · Page 3Linked to original sources
PubMed1997

Tumour necrosis factor alpha promoter gene polymorphism in sarcoidosis.

Biallelic polymorphisms in the promoter region of the TNF-alpha gene (TNFA) and in the first intron of the TNF-beta gene (TNFB) have been associated with variation in TNF-alpha production and with susceptibility to severe diseases. Among other functions, TNF-alpha plays a pivotal role in regulatory aspects of granuloma formation and sustenance. In sarcoidosis, a systemic granulomatous disorder of unknown aetiology, the clinical course of the disease has been associated with the patient's individual capacity of spontaneous TNF-alpha production by alveolar macrophages. We determined the TNFA and TNFB polymorphisms in 101 patients with pulmonary sarcoidosis and 216 healthy blood donors. A highly significant shift to the more uncommon TNFA2 allele was found in the Löfgren syndrome patient group, which represents the acute form of the disease with frequent spontaneous remission. The results show that gene frequencies of the TNFA gene variation are significantly different within the clinical forms of sarcoidosis, indicating that genetic predisposition for TNF-alpha production may play a role in the pathogenesis of the disease.

Humans↗
PubMed1997

Comparative study of CD26 as a Th1-like and CD30 as a potential Th2-like operational marker in leprosy.

In the last years we have been able to establish CD26 as an operational marker for a human Th1-like reaction in various granulomatous diseases. Recently, CD30 was described as a marker for a Th2-type reaction, where CD30 is preferentially expressed and its soluble form released by human T cell clones producing Th2-type cytokines. To evaluate the possibility of CD30 as an eventual operational marker for a human Th2-like reaction in vivo, we performed immunohistological stainings on frozen sections of skin biopsies from patients with lepromatous and tuberculoid leprosy. A maximum of three to four CD30-positive cells was found per section, and there was no difference in the accumulation of CD30-positive cells between the tuberculoid and the lepromatous form of leprosy. With respect to CD26-positive cells, a high number was found in tuberculoid leprosy in contrast to a greatly reduced expression of CD26 in lepromatous leprosy. We conclude that, while CD26 was confirmed as an operational marker for a Th1-like reaction in leprosy, CD30 does not represent an operational Th2 marker in this disease.

Biomarkers↗
PubMed1997

Macroschizonts of Theileria annulata as vaccine and diagnostic tools.

T. annulata-infected cells present infection-associated peptides. These peptides represent target molecules of the cytotoxic acting cells. Their preparation and characterization may help to develop a sub-unit vaccine. Our studies show that macroschizont-infected bovine cells can be used as parasite antigen in serology for the detection of parasite-specific antibodies in serum of infected animals. Primers derived from the macroschizont of T. annulata can be used as molecular tools for the detection of parasite DNA in blood samples of carrier cattle.

Animals↗
PubMed1997

[Pentoxifylline inhibits experimental bleomycin-induced fibrosing alveolitis].

Therapy of idiopathic pulmonary fibrosis (IPF) is directed at 1) inhibition of alveolitis and tissue damage, and 2) inhibition of matrix deposition. We and others have identified pentoxifylline (POF) as a promising drug in achieving these aims. For further clarification, we established a model of bleomycin-induced fibrosing alveolitis. Fisher 344 rats (n = 7 per group) were given bleomycin intratracheally once (0.7 U/100 g bw) and treated with POF (1.5 or 3 mg/kg bw per day i.p.), prednisolone (15 mg/kg bw i.m. per day), or sodium chloride solution (NaCL). The extent of inflammatory reactions was determined after 8 days by differentiation of cells of broncho-alveolar lavage (BAL) and by quantification of proliferating cells in lung interstitium subsequent to staining of the Ki-67 antigen. POF inhibited neutrophil alveolitis in BAL and reduced the amount of proliferating cells in the lungs significantly while prednisolone and NaCL did not. Both POF and prednisolone exerted a positive influence on postoperative weight loss as well as on lung weight increase subsequent to bleomycin instillation. The postoperative body weight loss and the lung weight increase after bleomycin instillation are most likely due to an inflammatory reaction subsequent to operation and bleomycin deposition. Tumor necrosis factor alpha (TNF-alpha) has been shown to be a key cytokine in bleomycin-induced fibrosing alveolitis as well as in IPF; it also exerts catabolizing effects. Since both POF and prednisolone are known to effectively inhibit proinflammatory cytokines and, among those, TNF-alpha, nonspecific antiinflammatory effects probably explain the benefits. Additionally, however, this study proved POF to be more effective in inhibition of BAL neutrophils and number of proliferating cells in lung interstitium. Further, it has been shown that POF, but not prednisolone, inhibits activation of neutrophil granulocytes and formation of reactive oxygen species. Thus we believe that the mechanism of action of xanthines might contribute to therapy of IPF. For further clarification, a prospective clinical study of POF in IPF therapy has been initiated.

Animals↗
PubMed1996

The use of reverse transcription polymerase chain reaction to analyse large numbers of mRNA species from a single cell.

A PCR method is described for determining the expression of multiple heterogeneous mRNAs from single cells. The total mRNA pool of a single selected cell is subjected to reverse transcription and subsequent tailing with poly(dA). This cDNA is preamplified by a sequence non-specific PCR protocol using oligo(dT)-containing primers. The single cell cDNA library obtained permits the analysis of virtually unlimited numbers of mRNA species per cell using sequence-specific PCR. This procedure of multiple mRNA analysis enables phenotyping of any cell for its mRNA composition and could be used to study the cytokine mRNA expression of individual human T cells ex vivo. The method should greatly facilitate the analysis of combinatorial expression of known genes in any cell.

Base Sequence↗
PubMed1996

Nitric oxide synthase: expression of the endothelial, Ca2+/calmodulin-dependent isoform in human B and T lymphocytes.

Nitric oxide (NO) is a pleiotropic mediator of a variety of cellular processes such as vasorelaxation, neurotransmission, and cytotoxicity. We studied the expression of the human endothelial, Ca2+/calmodulin-dependent NO synthase (NOS) isoform (ecNOS) in highly purified human lymphocytes from peripheral blood and tonsillar T cells. ecNOS mRNA was detected in IgD+ or IgD- B cells, peripheral blood and tonsillar T cells. Upon stimulation, ecNOS mRNA expression decreased in all these lymphocyte subpopulations. Germinal center T cells and follicular dendritic cells did not express ecNOS mRNA either in an unstimulated or in a stimulated state. ecNOS expression by human lymphocytes was further substantiated by its mRNA detection in lymphoid cell lines such as Raji, Daudi, and Jurkat. By the use of a specific monoclonal antibody, ecNOS was shown to be present in T cells from peripheral blood and in various germinal center cells of frozen tonsillar sections. These data are the first to demonstrate the expression of the endothelial ecNOS at mRNA and protein level in human lymphocytes.

B-Lymphocytes↗
PubMed1996

Human follicular dendritic cells and vascular cells produce interleukin-7: a potential role for interleukin-7 in the germinal center reaction.

Interleukin-7 (IL-7) has long been known as a potent growth factor in lymphocyte development. However, recent data obtained in vitro revealed additional functions for this cytokine, e.g. IL-7 influences the generation of cytotoxic T cells and NK cells, and in higher concentrations, activates monocytes in a manner similar to bacterial lipopolysaccharide. Furthermore, human tonsillar B cells are able to proliferate upon stimulation by IL-7 and cross-linking of the B cell receptor. Considering the latter role of IL-7 for B cell proliferation, we investigated which cells of the human immune system express IL-7 in vivo. mRNA expression of tonsillar cells was analyzed using the reverse transcription polymerase chain reaction, and protein expression was assessed by immunohistochemical staining of frozen sections. Among a variety of different immune cell types isolated from human tonsils, only follicular dendritic cells (FDC) expressed specific IL-7 products, whereas B and T cells were consistently negative. Immunohistochemical staining of tonsillar sections revealed the expression of immunoreactive IL-7 protein on FDC, and a pronounced expression could also be detected in oral mucosa and vascular endothelial cells. For the latter, we could also demonstrate mRNA expression in primary cultured cells. In light of the previous finding that IL-7 can act as a co-stimulus for the induction of proliferation in tonsillar B cells, these data suggest a role of IL-7 in the germinal center reaction. It is tempting to speculate that FDC may function as regulatory cells in B cell development in the tonsil, as epithelial nurse cells are thought to govern T cell development in the thymus.

B-Lymphocytes↗
PubMed1996

Assessment of mycobacterial DNA in cells and tissues of mycobacterial and sarcoid lesions.

In this study we applied a polymerase chain reaction (PCR) assay for the detection and species-specific identification of mycobacteria to samples from patients with sarcoidosis and mycobacterial infections and from control patients. The PCR-technique is based on the amplification of mycobacterial DNA coding for 16S rRNA, which is present in all mycobacterial species, and on the additional sequencing of the PCR fragment to determine the species. Mycobacterial DNA could be detected in lung tissues and bronchoalveolar lavage cells from cases of tuberculosis and infections with atypical mycobacteria. On the other hand, mycobacterial DNA was amplified only in lung tissue from one patient with sarcoidosis. Twenty-three samples from patients with sarcoidosis were negative for mycobacterial DNA. From our results we conclude that the granulomatous lesions in sarcoidosis may not be due to mycobacterial infections.

Base Sequence↗
PubMed1996

Molecular characterization of the gene locus of the human cell proliferation-associated nuclear protein defined by monoclonal antibody Ki-67.

The human antigen defined by the monoclonal antibody Ki-67, the 'Ki-67 protein', is an ubiquitously expressed human nuclear protein strictly associated with cell proliferation and is widely used in routine pathology as a 'proliferation marker' to measure the growth fraction in human tumours. In immunoblots of proteins from proliferating cells, Ki-67 detects two bands with the apparent molecular weights of 345 and 395 kDa. Recently we reported on the cloning and sequencing of the complete cDNA of the Ki-67 protein. We found two isoforms of cDNA with full lengths of 11.4 and 12.5 kb, respectively, likely formed by the alternative splicing of exon 7. The remarkable exon 13 at the 'centre' of this gene contains 16 homologous segments of 366 bp (Ki-67 repeats), each including a highly conserved new motif of 66 bp (Ki-67 motif). Computer analyses confirmed that the cDNAs encode for a new class of nuclear proteins. The complete gene locus of the Ki-67 protein, comprising a 74 bp 5' region and a 264 bp 3' region, has been sequenced and aligned to a continuous sequence of 29,965 bp length located on chromosome 10q25-ter. The gene is organized in 15 exons with sizes from 67 to 6845 bp and in 14 introns with sizes from 87 to 3569 bp. Three introns contain homologue copies of 'Alu-repeats'. Interestingly, the introns flanking the alternative spliced exon 7 are free of any consensus donor and acceptor splicing signal. All other intron-exon transitions contained a potential branch site. The complete 5' region including the first two exons represents a CpG-rich island. We found the transcription initiation site in exon two adjacent to the consensus sequence of a cap site. Upstream of this cap site no TATA- or CCAAT-box could be located, but downstream we found two remarkable directly repeated elements of 24 bp lengths each containing a TATA box in inverse orientation.

Amino Acid Sequence↗
PubMed1995

Limited and defined truncation at the C terminus enhances receptor binding and degranulation activity of the neutrophil-activating peptide 2 (NAP-2). Comparison of native and recombinant NAP-2 variants.

We have previously described a C-terminally truncated variant of the chemokine neutrophil-activating peptide 2 (NAP-2) that exhibited higher neutrophil-stimulating capacity than the full-size polypeptide. To investigate the impact of the NAP-2 C terminus on biological activity and receptor binding, we have now purified the novel molecule to homogeneity. Furthermore, we have cloned, expressed in Escherichia coli, and purified full-size recombinant NAP-2 (rNAP-2-(1-70)) and a series of C-terminally deleted variants (rNAP-2-(1-69) to rNAP-2-(1-64)). Biochemical and immunochemical analyses revealed that the natural NAP-2 variant was structurally identical to the rNAP-2-(1-66) isoform. As compared with their respective native and recombinant full-size counterparts, both molecules exhibited approximately 3-4-fold enhanced potency in the induction of neutrophil degranulation as well as 3-fold enhanced binding affinity for specific receptors on these cells. All other variants were considerably less active. The natural occurrence of a NAP-2 variant truncated by exactly four residues at the C terminus suggests that limited and defined proteolysis at this site plays a role in the regulation of the biological function of the chemokine.

Amino Acid Sequence↗
PubMed1995

An improved method for the species-specific assessment of mycobacteria in routinely formalin-fixed and paraffin-embedded tissues.

A polymerase chain reaction (PCR) assay for the rapid and species-specific diagnosis of mycobacterial infections in paraffin-embedded clinical specimens was developed using oligonucleotide primers to amplify a fragment of the DNA coding for the ribosomal 16S RNA of mycobacteria. The oligonucleotide primers amplified DNA from all 14 species of mycobacteria tested. By means of a reamplification protocol, as few as one to two mycobacteria could be detected in the presence of human DNA. The method of DNA isolation and amplification was applied on sections of routinely formalin-fixed and paraffin-embedded tissues. PCR for the beta-actin gene served as a control for successful DNA isolation. Mycobacterial DNA could be detected in cases of mycobacterial infections. The mycobacterial species was determined by additional sequencing of the PCR fragment. This PCR method may be a powerful tool for the diagnosis of mycobacterial infections from histopathological material and for the assessment of those mycobacteria that cannot readily be cultured, such as Mycobacterium leprae.

Base Sequence↗
PubMed1995

The human germinal centre cells, follicular dendritic cells and germinal centre T cells produce B cell-stimulating cytokines.

Cytokine gene expression was investigated in the germinal centre constituents of follicular dendritic cells and germinal centre T cells and compared to the mRNA expression of nongerminal centre tonsillar cells. Cells were isolated from human tonsils by preenrichment with MACS and subsequent FACS sorting. Cytokine gene expression was investigated by intronspanning RT-PCR for IL-1 alpha, IL-1 beta, IL-2, IL-4, IL-5, IL-6, IL-10, IFN-alpha, IFN-beta, IFN-gamma, and TNF-alpha. Frequency of cytokine-producing cells and the cytokine production pattern of single cells were determined by single cell PCR. Furthermore, cytokine protein expression was investigated by immunohistology. Using these methods, we found a strong production of IL-1 beta mRNA and protein in a small percentage of FDC. Germinal centre T cells showed production of IL-2, IL-4, IL-10, IFN-gamma, and TNF-alpha mRNA. The mRNAs of these cytokines could also be detected at the single cell level; as they were produced in a high percentage of germinal centre T cells, whereas immunohistological staining was negative, we conclude that a high percentage of germinal centre T lymphocytes produce IL-2, IL-4, IL-10, IFN-gamma, and TNF-alpha in low concentrations in contrast to T cells outside the germinal centre, in which strong cytokine production in few cells was shown earlier.

B-Lymphocytes↗
PubMed1995

Follicular dendritic cells productively infected with immunodeficiency viruses transmit infection to T cells.

Lymphoid organs have been proposed to function as the major reservoir for the human immunodeficiency virus type 1 (HIV-1). Within lymphatic tissues germinal centers represent foci of rapidly proliferating B cells governed by the interaction between B and T cells and follicular dendritic cells (FDC). Accumulating evidence suggests an important role of FDC in the pathophysiology of the acquired immunodeficiency syndrome. Direct proof for the infectibility of FDC with HIV-1 has been lacking until recently when we were able to demonstrate a CD4-independent infection of FDC in vitro. Here we report that in vitro HIV-1-infected human FDC do not only contain proviral DNA, but also produce the virus, and transmit the infection to T cells. Furthermore, electron microscopical studies on ex vivo isolated FDC from simian immunodeficiency virus (SIV)-infected rhesus monkeys revealed typical virus budding. In addition, FDC from SIV-infected rhesus monkeys transmitted the infection to T cells in vitro. Due to this central role within the immune response FDC may serve as preferential targets for HIV both by trapping of virions on their surfaces and by productive infection. During disease FDC become productively infected and may, thus, be regarded as crucial elements in viral dissemination.

Animals↗
PubMed1995

Double-blind developmental evaluation at 1-year corrected age of 597 premature infants with birth weights from 500 to 1350 grams enrolled in three placebo-controlled trials of prophylactic synthetic surfactant. American Exosurf Neonatal Study Group I.

Infants enrolled in three clinical trials of prophylactic treatment for respiratory distress syndrome with a single dose of synthetic surfactant (Exosurf Neonatal) or air placebo were monitored through 1-year adjusted age. A total of 1046 infants with birth weights from 500 to 1350 gm were enrolled in the three trials; of the 735 infants who survived to 1 year of age, follow-up evaluations were completed for 597 (80%, air placebo group; 82%, synthetic surfactant group). Infants in the air placebo and synthetic surfactant treatment groups had no differences in general health, growth, or nerodevelopmental outcomes or impairments. These follow-up results at 1-year adjusted age for infants who received a single dose of synthetic surfactant indicate that a single dose of synthetic surfactant reduces mortality without increasing the absolute number or proportion of infants with impairments at 1 year of age.

Air↗
PubMed1995

Health and neurodevelopmental outcome at 1-year adjusted age in 508 infants weighing 700 to 1100 grams who received prophylaxis with one versus three doses of synthetic surfactant. American Exosurf Neonatal Study Groups I and II.

A three-dose prophylactic regimen of synthetic surfactant replacement has been shown to improve neonatal and 1-year survival rates in infants of 700 to 1100 gm birth weight when compared with a single prophylactic dose. The purpose of this study was to evaluate the growth, development, and late morbidity at 1 year adjusted age among the survivors of the 826 patients enrolled in the protocol. Complete follow-up data were obtained for 75% of the survivors in both groups. Chronic lung disease, need for respiratory support, neurologic disease requiring medication, visual or auditory impairments, and the incidence and severity of retinopathy of prematurity were equivalent in the two groups. The frequency of neurodevelopmental impairment was also comparable in the groups that received one dose versus three doses: moderate to severe cerebral palsy was found in 9% versus 6%, mental retardation assessed by Bayley Scales of Infant Development scores less than 69 was found in 16% vs 14%, and moderate to severe impairments of any kind were found in 33% vs 24%, respectively. Furthermore, the absolute number of impaired survivors was 92 in the three-dose group versus 106 in the one-dose group, despite a higher survival rate in the three-dose group. This study demonstrates that developmental outcomes of infants weighing 700 to 1100 gm who received three prophylactic doses of synthetic surfactant are at least as good as those of infants receiving a single dose, and that improving survival rates of very premature infants with synthetic surfactant does not result in increased numbers of infants with impairments.

Child Development↗