Biomedical subjects

G Schröder

Publications and source records attributed to G Schröder.

At least 19 recordsLinked to original sources

PubMed2005

Trichophyton rubrum-induced inflammatory tinea capitis in a 63-year-old man.

Tinea capitis caused by Trichophyton rubrum is a rare event worldwide. We report on an elderly otherwise healthy man with inflammatory fungal disease of the scalp caused by this pathogen. He had no signs of concomitant mycosis of the skin and nails and no underlying immunosuppressive disease. The fungal infection primarily had been misdiagnosed in terms of a pyoderma. Failure of antibiotic treatment, a positive mycological study and molecular diagnostics eventually led to the correct diagnosis. After systemic and local administration of terbinafine the lesion improved totally.

Humans↗

PubMed2005

Candidosis and aspergillosis as autopsy findings from 1994 to 2003.

We analysed the autopsy records of the Greifswald University Institute of Pathology (located in Eastern Germany) in respect of findings of candidosis and aspergillosis from 1994 to 2003. We also present eight immature aborted fetuses and premature infants with a mycosis. In a total of 2027 autopsies we found 164 cases of invasive candidosis and aspergillosis (8.1%) including a combination of both on four occasions. Other authors cited between 0.7 and 7.3%. In these 10 years in our material mycoses and in particular candidosis increased in spite of slightly decreased numbers of autopsies. The differences comparing the 5-years periods (1994-98 and 1999-2003) are highly significant for both mycoses and candidosis. They are not significant for aspergillosis. A similar relationship was observed in the distribution of mycotic organs and causative origin for candidosis alone. In the last 5 years the gastrointestinal and respiratory tracts, including the peritoneum, were more frequently infected by Candida. Non-haematological neoplasia and pneumonia as basic diseases more often appeared in cases of candidosis. All eight immature aborted fetuses and premature infants suffered from candidosis. The survey confirms the importance of autopsy as a tool for education and quality control in medical diagnostic and therapeutic activity in the field of mycoses, too.

Aborted Fetus↗

PubMed2004

A patient with myelofibrosis complicated by refractory ascites and portal hypertension: to tips or not to tips? A case report with discussion of the mechanism of ascites formation.

In patients with myelofibrosis, clinically significant portal hypertension is known to be predominantly presinusoidal; however, the exact mechanisms are still controversial. The pathophysiology is particularly enigmatic in those patients without histological and angiographic evidence of significant intra- or extrahepatic obstruction to portal blood flow, respectively. Moreover, ascites formation has been reported in such cases, but in general is rare in presinusoidal portal hypertension. Here we present such a patient in which ascites developed even in the presence of unchanged serum protein levels (oncotic pressure) and was refractory to sodium restricted diet and high-dose diuretic treatment. A discussion on the parameters influencing fluid exchange and ascites formation particularly emphasizing the potential importance of the hyperdynamic circulation in this case is given. Finally, the patient was treated by implanting a transjugular intrahepatic shunt (TIPS), exerting a diuretic effect sufficient enough to avoid re-formation of ascites for several months. However, ascites re-accumulated potentially due to the appearance of ectopic peritoneal myeloid metaplasia and the patient died soon afterwards. In conclusion, TIPS may be considered as rescue management for refractory ascites secondary to portal hypertension, but caution in respect to the presence and/or development of peritoneal or other ectopic haematopoesis has to be taken.

Aged↗

PubMed2001

[Interferon beta-1b (Betaferon)therapy in patients with relapsing-remitting multiple sclerosis: findings of a prospective, multi-center study of disease progression].

In a survey of disease course, the efficacy and tolerability of 24-month interferon beta-1b therapy for relapsing remitting multiple sclerosis (RRMS) were evaluated in 410 patients. The investigation aimed at obtaining data from general practice and of possibly unknown, unexpected adverse reactions. In the 241 patients still on therapy, efficacy was rated after 24 months as "good" or "very good" in 75% of cases. After 24 months, 36.9% of the patients had no exacerbation (baseline 0.3%). Annual exacerbation rates dropped from 1.5 before treatment to 0.7 in the second treatment year. In the 2 years before treatment, 66.2% had worsened by at least 0.5 points on the extended disability status scale (EDSS). This proportion was reduced to 41.2% after 2 years of treatment. The safety profile corresponded to results from controlled trials. This postmarketing survey supports data from the published controlled interferon beta-1b studies and confirms the main effects of this therapy under routine conditions in general practice.

Adjuvants, Immunologic↗

PubMed2001

Molecular and biochemical characterization of three aromatic polyketide synthase genes from Rubus idaeus.

Three polyketide synthase genes (PKS1, PKS2, PKS3) from cell suspension cultures of raspberry (Rubus idaeus L. cv. Royalty) were characterized. They showed high similarity in both their nucleotide and deduced amino acid sequences. All three proteins contain the amino acid residues identified in previous work as essential for chalcone synthase (CHS) function. Enzyme activities were investigated after heterologous expression in Escherichia coli. RiPKS1 is a typical naringenin CHS that synthesizes the chalcone as the main reaction product, and p-coumaryltriacetic acid lactone (CTAL) as a minor by-product. RiPKS3 differed from RiPKS1 in four positions (K49R, M64R, P120L, V188A), and the products in vitro were predominantly CTAL and low levels of chalcone. RiPKS2 had the same four differences from RiPKS1 as RiPKS3, but in addition two further exchanges (R259H, F344L), and the protein had no detectable enzyme activity. Experiments with RiPKS1 containing either 259H or 344L showed that each of the exchanges was sufficient to completely eliminate enzyme activity. These experiments identify amino acid residues in CHS which are important for folding of the tetraketide intermediate to the chalcone (PKS3) and which are in general essential for CHS activity (PKS2). The possible functions of these residues are discussed.

Amino Acid Sequence↗

PubMed2001

Transmission of a multiresistant Pseudomonas aeruginosa strain at a German University Hospital.

Over 15 months, 60 patients at a German University Hospital became infected or colonized by a multiresistant Pseudomonas aeruginosa strain, which was isolated from tracheal secretions, blood, urine, venous catheters, ascites and several wounds. Most patients had undergone invasive treatment (surgery, cancer therapy). The genetic relationship of the isolates was investigated by pulsed field gel electrophoresis. The isolates were resistant to beta-lactam antibiotics, including carbapenems and aztreonam, to aminoglycosides and quinolones. The only in vitro susceptibility was to polymyxin B. Extensive sampling was carried out to identify contaminated medical devices, surfaces or media (water, food). Samples were taken from doctors and nursing staff and various treatment procedures were observed for several weeks. The handling of respirators, resuscitation tubes, urine bottles, and bedpans resulted in the contamination of the patients' environment, although most devices were cleaned and disinfected with automatic washer/disinfectors. Several wash basins on the intensive care unit were contaminated, but none of the drinking water samples showed any growth of P. aeruginosa. We recommend the strict use of gloves and strict application of alcoholic hand disinfectants immediately after discarding the gloves. The chain of infection ceased after strict cohort isolation and the subsequent introduction of the specific hygiene regime.

Adult↗

PubMed2000

The promoter of the Vicia faba L. gene VfEnod12 encoding an early nodulin is active in cortical cells and nodule primordia of transgenic hairy roots of Vicia hirsuta as well as in the prefixing zone II of mature transgenic V. hirsuta root nodules.

A full-length cDNA encoding the Vicia faba L. early nodulin VfEnod12 was isolated. The deduced protein sequence specified a 90 amino acid protein with a MW of 10206 and contained a putative signal peptide sequence followed by PPX(3) repeats characteristic of Enod12 proteins. The VfEnod12 gene was found to be expressed specifically in root nodules as early as 3 days post inoculation with Rhizobium leguminosarum bv. viciae. In mature nodules, VfEnod12 transcripts were confined to the prefixing zone II. A 3.3 kb genomic fragment carrying the complete VfEnod12 coding region was isolated. No intervening sequences were identified in the coding region. A promoter fragment carrying the -692/-41 region mediated reporter gene expression in root cortical cells, nodule primordia and the prefixing zone II of transgenic Vicia hirsuta root nodules. This fragment contained a putative binding site for the transcription factor ENBP1. In contrast to the highly conserved terminal AATAA motif of the ENBP1 binding site of known Enod12 promoters, the VfEnod12 promoter was characterized by an altered terminal AATAT sequence. This alteration did not interfere with VfEnod12 promoter activity in transgenic roots and nodules of V. hirsuta.

Journal Article↗

PubMed2000

Immune response after adenoviral gene transfer in syngeneic heart transplants: effects of anti-CD4 monoclonal antibody therapy.

BACKGROUND: E1-deleted adenoviral vectors are frequently used for in vivo gene therapy. However, gene expression after adenovirus-(ad) mediated gene transfer is known to be transient due to the generation of an immune response against virus-infected cells. In this study, we asked whether an anti-CD4 mAb (RIB 5/2) treatment may improve the gene transfer into rat cardiac grafts. METHODS: We injected recombinant ad-constructs encoding for Escherichia coli beta-gal into syngeneic rat heart transplants via the proximal aorta. One-half of the recipients of genetically modified grafts received the anti-CD4 mAb RIB 5/2, whereas the other half received no monoclonal antibody treatment. Genetically unmodified isografts without any treatment of the recipients were used as additional controls. At different time points hearts were harvested and analyzed for reporter gene expression, intragraft cellular infiltration, and cytokine gene expression (quantitative "real time" reverse transcriptase polymerase chain reaction). Serum samples were analyzed for anti-ad-Ig using enzyme-linked-immunosorbent-assay. RESULTS: In control animals the beta-gal reporter gene expression slowly increased until day 7 and then declined. The immunohistological and reverse transcriptase polymerase chain reaction intragraft analyses revealed a strong inflammatory response (cellular infiltration, cytokine expression) in ad-transfected grafts that may explain the delayed expression and fast down-regulation of the transgene. Treatment with RIB 5/2 mAb resulted in a faster and prolonged reporter gene expression, reduced graft infiltration, reduced anti-ad-Ig titers and less interferon-gamma up-regulation. CONCLUSIONS: Our results indicate that modulation of the anti-ad immune response using a nondepleting anti-CD4 mAb may increase the efficiency of ad-vectors for gene therapy in the transplant setting.

Adenoviridae↗

PubMed2000

Genomic organization and expression properties of the VfENOD5 gene from broad bean (Vicia faba L.).

A full-length cDNA encoding the broad bean (Vicia faba L.) early nodulin VfENOD5 was isolated from a nodule cDNA library. In addition to the ENOD5 homologues from other legumes the derived VfENOD5 amino acid sequence also displayed homologies to the phytocyanin-related nodulins GmENOD55-2, MtENOD16, and MtENOD20. A close inspection of the ENOD5 proteins from broad bean, pea and vetch indicated that all these nodulins possess a putative C-terminal GPI-anchor signal sequence. This novel finding supports the hypothesis that ENOD5 is an arabinogalactan protein. Tissue print hybridizations revealed that the broad bean ENOD5 gene was not only expressed in the central tissues of root nodules. In contrast to other legumes hybridizing transcripts were also be detected in a narrow zone within the peripheral nodule tissues. Sequence analysis of a genomic clone indicated the presence of a single intron interrupting the VfENOD5 coding region at a position precisely corresponding to the MtENOD16 and MtENOD20 introns.

Journal Article↗

PubMed2000

Characterization of epidemic and nonepidemic methicillin-resistant Staphylococcus aureus strains in a university hospital in northeast Germany.

The aim of this study was to analyze methicillin-resistant Staphylococcus aureus strains isolated during a 1-year period by means of pulsed-field gel electrophoresis, resistance phenotyping and determination of biochemical features. Eight different resistance phenotypes with the predominant resistance type Pen Oxa Cip (penicillin, oxacillin, ciprofloxacin) were observed. None of the strains tested exhibited decreased susceptibility to vancomycin, but two strains were resistant to mupirocin. Genetic relatedness of methicillin-resistant Staphylococcus aureus isolates could be shown for two outbreaks, one of which was caused by a clone with an epidemic potential concerning duration of colonization/infection of patients and dissemination of the strains in the hospital.

Anti-Bacterial Agents↗

PubMed2000

Ischemia/reperfusion injury-mediated down-regulation of adenovirus-mediated gene expression in a rat heart transplantation model is inhibited by co-application of a TNFRp55-Ig chimeric construct.

E1-deleted adenoviral vectors are efficient vectors for somatic gene therapy. Recently, we have shown that intratracheal application of an adenoviral reporter construct leads to significant reporter gene expression in rat lungs within 24 h. In contrast, reporter gene expression in syngeneic rat heart transplants after adenovirus-mediated gene transfer was delayed. Since the adenovirus cannot replicate, down-regulation of the hCMV-IE promoter controlled reporter gene expression in initially infected cells by cytokines, which are released as a result of ischemia/reperfusion injury, might be involved. In order to investigate the role of proinflammatory cytokines, eg TNF-alpha in affecting hCMV-IE promoter-driven reporter gene expression, transient blockade of TNF-alpha was achieved by local co-application of an Ad-construct encoding for a soluble TNFRp55-Ig chimeric molecule in a syngeneic rat heart transplantation model. Co-application of the reporter construct together with the TNFRp55-Ig chimeric molecule significantly increased the early reporter gene expression after transplantation. Moreover, infiltration of inflammatory cells (T cells, macrophages, NK cells) and production of TNF-alpha in the transplant was markedly reduced. Our results indicate that: (1) proinflammatory cytokines are involved in down-regulation of reporter gene expression in ischemia/reperfusion injured tissues; and (2) inhibition of TNF-alpha might be a useful tool to increase early gene expression in gene therapy protocols, particularly in transplantation. Gene Therapy (2000) 7, 1238-1243.

Adenoviridae↗

PubMed2000

Indole alkaloid biosynthesis in Catharanthus roseus: new enzyme activities and identification of cytochrome P450 CYP72A1 as secologanin synthase.

The molecular characterization of CYP72A1 from Catharanthus roseus (Madagascar periwinkle) was described nearly a decade ago, but the enzyme function remained unknown. We now show by in situ hybridization and immunohistochemistry that the expression in immature leaves is epidermis-specific. It thus follows the pattern previously established for early enzymes in the pathway to indole alkaloids, suggesting that CYP72A1 may be involved in their biosynthesis. The early reactions in that pathway, i.e. from geraniol to strictosidine, contain several candidates for P450 activities. We investigated in this work two reactions, the conversion of 7-deoxyloganin to loganin (deoxyloganin 7-hydroxylase, DL7H) and the oxidative ring cleavage converting loganin into secologanin (secologanin synthase, SLS). The action of DL7H has not been demonstrated in vitro previously, and SLS has only recently been identified as P450 activity in one other plant. We show for the first time that both enzyme activities are present in microsomes from C. roseus cell cultures. We then tested whether CYP72A1 expressed in E. coli as a translational fusion with the C. roseus P450 reductase (P450Red) has one or both of these activities. The results show that CYP72A1 converts loganin into secologanin.

Asteraceae↗

PubMed2000

Funguria and Candida-specific immunoglobulins in patients with systemic candidosis.

UNLABELLED: Funguria, indirect anti-Candida haemagglutination test (C-IHT) and Candida-specific immunoglobulins C-IgM, C-IgG and C-IgA were investigated under suspicion of systemic candidosis in critically ill patients. A total of 143 urine cultures were studied for Candida from 74 adults and a median count of log 3.0 CFU ml-1 was found. Most isolated Candida species were Candida albicans and Candida glabrata. In 14 cases of candidaemia there was no regular agreement between the finding of Candida species in blood and urine. In cases with candiduria > = or log 3.0 CFU ml-1 a stronger increase of C-IHT titres and all three Candida-specific immunoglobulins after 5-7 days was observed. Some statistically significant correlations were found between the levels of urinary yeast counts and immunological parameters concerning C-IHT, C-IgA and C-IgG on the first day and after 5-7 days. Clinical findings in some cases coincided well with funguria and courses of titres before and after treatment. CONCLUSION: In critically ill patients suspected of having systemic candidosis not only blood cultures should be made. Cultural studies with specimens taken from different sites including funguria are essential for a complete specific serological investigation.

Aged↗

PubMed1999

Hearing screening in healthy newborns: feasibility of different methods with regard to test time.

Clicked-evoked otoacoustic emissions and automated auditory brainstem response are both considered appropriate hearing screening tools. The aim of this study was to compare their practicability with respect to test duration. In the first part of the study, clicked-evoked otoacoustic emissions were recorded in 388 healthy infants on the newborn ward in the first days of life. To reduce false positive rates of screening, clicked-evoked otoacoustic emissions combined with automated auditory brainstem response measurement (A-ABR, Algo 1E and Algo 2) were used in a second investigation. Fifty-five newborns screened by this two-stage method recorded an increased pass rate. The new digital technique of automated auditory brainstem response measurement (Algo 1E and Algo 2) employed in the second part of the study has a test time even shorter than that of clicked-evoked otoacoustic emissions and is no longer a time-consuming test due to improved technology of the second generation of automated auditory brainstem response equipment. Screening including preparation and follow-up time took 9.43 min (Algo 1E) and 8.26 min (Algo 2) respectively and was thus less time-consuming than reported in former studies.

Audiometry, Evoked Response↗

PubMed1999

Light-induced cytochrome P450-dependent enzyme in indole alkaloid biosynthesis: tabersonine 16-hydroxylase.

Vinblastine and vincristine are two medically important bisindole alkaloids from Catharanthus roseus (Madagascar periwinkle). Attempts at production in cell cultures failed because a part of the complex pathway was not active, i.e. from tabersonine to vindoline. It starts with tabersonine 16-hydroxylase (T16H), a cytochrome P450-dependent enzyme. We now show that T16H is induced in the suspension culture by light and we report the cloning of the cDNA. The enzyme was expressed in Escherichia coli as translational fusion with the P450 reductase from C. roseus, and the reaction product was identified by mass spectrometry. The protein (CYP71D12) shares 47-52% identity with other members of the CYP71D subfamily with unknown function. The induction by light was strongly enhanced by a nutritional downshift (transfer into 8% aqueous sucrose). We discuss the possibility that the entire pathway to bisindoles can be expressed in suspension cultures.

Alkaloids↗

PubMed1999

Native acridone synthases I and II from Ruta graveolens L. form homodimers.

Acridone synthase II cDNA was cloned from irradiated cell suspension cultures of Ruta graveolens L. and expressed in Escherichia coli. The translated polypeptide of Mr 42,681 revealed a high degree of similarity to heterologous chalcone and stilbene synthases (70-75%), and the sequence was 94% identical to that of acridone synthase I cloned previously from elicited Ruta cells. Highly active recombinant acridone synthases I and II were purified to apparent homogeneity by a four-step purification protocol, and the affinities to N-methylanthraniloyl-CoA and malonyl-CoA were determined. The molecular mass of acridone synthase II was estimated from size exclusion chromatography on a Fractogel EMD BioSEC (S) column at about 45 kDa, as compared to a mass of 44 +/- 3 kDa found for the acridone synthase I on Superdex 75. Nevertheless, the sedimentation analysis by ultracentrifugation revealed molecular masses of 81 +/- 4 kDa for both acridone synthases. It is proposed, therefore, that the acridone synthases of Ruta graveolens are typical homodimeric plant polyketide synthases.

Acyltransferases↗

PubMed1999

The Sinorhizobium meliloti insertion sequence (IS) elements ISRm102F34-1/ISRm7 and ISRm220-13-5 belong to a new family of insertion sequence elements.

The Sinorhizobium meliloti insertion sequence (IS) elements ISRm102F34-1 and ISRm220-13-5 are 1481 and 1550 base pairs (bp) in size, respectively. ISRm102F34-1 is bordered by 15 bp imperfect terminal inverted repeat sequences (two mismatches), whereas the terminal inverted repeat of ISRm220-13-5 has a length of 16 bp (two mismatches). Both insertion sequence elements generate a 6-bp target duplication upon transposition. The putative transposase enzymes of ISRm102F34-1 and ISRm220-13-5 consist of 449 or 448 amino acid residues with predicted molecular weights of 50.7 or 51.3 kDa and theoretical isoelectric points of 10.8 or 11.1, respectively. ISRm102F34-1 is identical in 98.9% of its nucleotide sequence to an apparently inactive copy of an insertion sequence element, designated ISRm7, which flanks the left-end of the nodule formation efficiency (nfe) region of plasmid pRmeGR4b of S. meliloti strain GR4. ISRm102F34-1 and ISRm220-13-5 are closely related since they show an overall identity of 57.0% at the nucleotide sequence level and of 47.3% at the deduced amino acid level of their putative transposases. Both insertion sequence elements displayed significant similarity to the Xanthomonas campestris ISXc6 and its homolog IS1478a. Since none of these insertion sequence elements could be allocated to existing families of insertion sequence elements, a new family is proposed. Analysis of the distribution of ISRm102F34-1/ISRm7 in various local S. meliloti populations sampled from Medicago sativa, Medicago sphaerocarpa and Melilotus alba host plants at different locations in Spain revealed its presence in 35% of the isolates with a copy number ranging from 1 to 5. Furthermore, ISRm102F34-1/ISRm7 homologs were identified in other rhizobial species.

Amino Acid Sequence↗

PubMed1999

Flavonoid hydroxylase from Catharanthus roseus: cDNA, heterologous expression, enzyme properties and cell-type specific expression in plants.

We investigated the P450 dependent flavonoid hydroxylase from the ornamental plant Catharanthus roseus. cDNAs were obtained by heterologous screening with the CYP75 Hf1 cDNA from Petunia hybrida. The C. roseus protein shared 68-78% identity with other CYP75s, and genomic blots suggested one or two genes. The protein was expressed in Escherichia coli as translational fusion with the P450 reductase from C. roseus. Enzyme assays showed that it was a flavonoid 3', 5'-hydroxylase, but 3'-hydroxylated products were also detected. The substrate specificity was investigated with the C. roseus enzyme and a fusion protein of the Petunia hybrida CYP75 with the C. roseus P450 reductase. Both enzymes accepted flavanones as well as flavones, dihydroflavonols and flavonols, and both performed 3'- as well as 3'5'-hydroxylation. Kinetics with C. roseus cultures on the level of enzyme activity, protein and RNA showed that the F3'5'H was present in dark-grown cells and was induced by irradiation. The same results were obtained for cinnamic acid 4-hydroxylase and flavanone 3beta-hydroxylase. In contrast, CHS expression was strictly dependent on light, although CHS is necessary in the synthesis of the F3'5'H substrates. Immunohistochemical localization of F3'5'H had not been performed before. A comparison of CHS and F3'5'H in cotyledons and flower buds from C. roseus identified CHS expression preferentially in the epidermis, while F3'5'H was only detected in the phloem. The cell-type specific expression suggests that intercellular transport may play an important role in the compartmentation of the pathways to the different flavonoids.

Acyltransferases↗