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Biomedical subjects

D Müller

Publications and source records attributed to D Müller.

At least 199 records · Page 11Linked to original sources
PubMed1996

Synthetic wound dressings--evaluation of interactions with epithelial and dermal cells in vitro.

Comparative testing of seven wound dressings (WD) has been performed with human HaCaT keratinocyte and mouse 3T3 fibroblast cultures. To assess biocompatibility, morphologic examinations were combined with cell counting. Supernatants were subjected to measurements of tissue peptide antigen (TPS), soluble intercellular adhesion molecule 1 (ICAM-1), and interleukins (IL-1 alpha, -1 beta, -6). Furthermore, monoxygenation, the reduced glutathione/oxidized gluthathione (GSH/GSSG) ratio and lipid peroxides were determined. Initial morphologic events were noted within the first day of exposure to WD. After 72 h, inhibition of cell growth was observed in the presence of hydrocolloids and hydrogels. The cytochrome-P-450-dependent ethoxyresorufin 0-deethylation rate and the GSH/GSSG ratio were not altered by WD in HaCaT cells. Lipid peroxide generation, IL-1 and ICAM-1 were scarcely detectable. TPS and IL-6 release indicate the presence of an 'activated stage' of keratinocytes and fibroblasts exposed to WD. Peptide release in vivo may contribute to the beneficial effects of modern dressings in the treatment of superficial cutaneous wounds.

3T3 Cells↗
PubMed1996

Natriuretic peptides in the human testis: evidence for a potential role of C-type natriuretic peptide in Leydig cells.

Functional studies indicate that natriuretic peptides have direct effects on Leydig cells of the testis. In this report, we demonstrate local synthesis of one member of the natriuretic peptide family, C-type natriuretic peptide (CNP), in Leydig cells of human testes. Using RT-PCR assays, messenger RNA (mRNA) for the CNP precursor was detected in human testis and found to be prominently expressed in Leydig cells. Immunohistochemical analyses revealed CNP to be almost exclusively associated with Leydig cells. Distinct differences in the staining intensity-including cells without detectable staining-suggest a heterogeneity of CNP expression within the Leydig cells. Moreover, the presence of transcripts for the CNP receptor, a particulate guanylate cyclase, termed GC-B, was demonstrated by RT-PCR in human testis and in isolated Leydig cells. The expression of this receptor in human testis membranes could be confirmed by affinity labeling with 125I-labeled CNP. These findings demonstrate, for the first time, the production of a natriuretic peptide in human Leydig cells. The occurrence of CNP and its receptor in the human testis points to a local role of the peptide, presumably acting in an auto- or paracrine manner to modulate organ-specific functions.

Adult↗
PubMed1996

Intrahepatic high-grade malignant non-Hodgkin lymphoma in a patient with chronic hepatitis C infection.

A 61-year-old white female with chronic hepatitis C virus (HCV) infection first diagnosed in 1994 was admitted with two newly discovered lesions in the liver suspected to represent hepatocellular carcinoma. The alpha-1-fetoprotein (AFP) level was within normal limits and there was neither clinical nor sonographic evidence of liver cirrhosis. Fine needle aspiration, however, showed an high-grade malignant centroblastic non-Hodgkin lymphoma (NHL). Staging failed to confirm extrahepatic involvement. Both a cryoglobulinemia and HIV infection were ruled out. Although the coincidence of HCV infection and NHL is not well recognized, recent studies have indicated an increased incidence of NHL and hepatitis C in up to 38% of patients with cryoglobulinemia. In these patients, the diagnosis is always one of a low-grade lymphoma. Based on its lymphoproliferative characteristics, an etiologic role for HCV in the development of NHL has been discussed, though the exact pathogenesis remains unclear.

Biopsy↗
PubMed1996

Delayed hypersensitivity reactions to corticosteroids applied to mucous membranes.

Despite the widespread use of corticosteroids on the mucous membranes of the nose, eye and bronchial tree, mucosal contact sensitivity has apparently been uncommon. However, since the introduction of new corticosteroids such as tixocortol pivalate and budesonide, mucosal contact sensitivity, particularly that affecting the nasal mucosa, has increasingly been reported. Contact allergy on other mucosal surfaces and in the bronchial tree is very rare. We report three women who had contact allergy to tixocortol pivalate or budesonide in nasal sprays, and one woman who had an allergic contact stomatitis from tixocortol pivalate in oral lozenges.

Administration, Intranasal↗
PubMed1995

A prokaryotic potassium ion channel with two predicted transmembrane segments from Streptomyces lividans.

We report the identification, functional expression, purification, reconstitution and electrophysiological characterization of an up to now unique prokaryotic potassium ion channel (KcsA). It has a rectifying current-voltage relationship and displays subconductance states, the largest of which amounts to A approximately equal to 90 pS. The channel is blocked by Cs- ions and gating requires the presence of Mg2+ ions. The kcsA gene has been identified in the gram-positive soil bacterium Streptomyces lividans. It encodes a predicted 17.6 kDa protein with two potential membrane-spanning helices linked by a central domain which shares a high degree of similarity with the H5 segment conserved among eukaryotic ion channels. Multiple alignments of deduced amino acids suggest that the novel channel has the closest kinship to the S5, H5 and S6 regions of voltage-gated K+ channel families, mainly to the subfamily represented by the Shaker protein from Drosophila melanogaster. Moreover, KcsA is most distantly related to eukaryotic inwardly rectifying channels with two putative predicted transmembrane segments.

Amino Acid Sequence↗
PubMed1995

DNA recognition site analysis of Xenopus winged helix proteins.

DNA binding proteins of the winged helix family contain a conserved 110 amino acid region, the fork head/HNF-3 domain. Three members of the recently described XFD (Xenopus fork head domain related) multigene family in the frog Xenopus laevis that contain this DNA-binding domain have been studied. We determined the in vitro DNA recognition sequences by means of two independent methods: PCR supported site selection with degenerated deoxyoligonucleotides and affinity chromatography of genomic Xenopus DNA fragments. In contrast to a remarkable sequence divergence within their protein sequence of the fork head domains, all three proteins share a similar 7 bp DNA target motif. The protein-DNA interaction has been studied by means of DMS interference and hydroxyl radical footprinting. A region of 18 bp encompassing the 7 bp target motif is sufficient to confer binding and specificity. The specificity of binding could be attributed on the DNA level to residues located 5' to the 7 bp core region, and on the protein level most likely to a region within the first half of the fork head domain. The possible role of specific nucleotides within the target site in binding the protein is discussed in the context of the current crystal structure of the complex of this domain with DNA.

Amino Acid Sequence↗
PubMed1995

Urinary excretion of adenosine deaminase binding protein in neonates treated with tobramycin.

The potential tubulotoxicity of tobramycin and cefotaxim were assessed in neonates by measuring the urinary level of adenosine deaminase binding protein (ABP) and urinary alpha 1-microglobulin and beta 2-microglobulin. In a prospective study, 33 neonates who received tobramycin and cefotaxim for suspected neonatal sepsis were compared with 48 untreated newborns during the first 10 days of life. The urinary concentrations of ABP and its excretion rates, corrected for body weight and body surface area, were significantly increased from the 1st day of treatment. Urinary alpha 1-microglobulin and beta 2-microglobulin were not elevated under tobramycin and cefotaxim during the first 2 days of treatment. We conclude that ABP may be a sensitive marker for the detection of proximal renal tubular injury during tobramycin and cefotaxim treatments of neonates. The increase in urinary ABP which occurs before an elevation of urinary alpha 1-microglobulin and beta 2-microglobulin may reflect earlier structural than functional alterations. However, since none of the treated infants had signs of electrolyte disorders or glomerular dysfunction, the clinical relevance of ABP measurement should be reevaluated.

Anti-Bacterial Agents↗
PubMed1995

Failures of epicardial and transvenous leads for implantable cardioverter defibrillators.

Lead failures constitute a major risk for patients with an implantable cardioverter defibrillator (ICD). However, data about the incidence and patterns of ICD-lead failures in a larger population are lacking. We analyzed the short-term and midterm performance of 27 epicardial and 103 nonthoracotomy ICD-lead systems during a follow-up period of 36 +/- 21 months and 22 +/- 10 months, respectively (p < 0.05). The failure rate was 5 (19%) of 27 in the epicardial and 6 (6%) of 103 in the nonthoracotomy group (p < 0.05). The most common symptom was erroneous detection of ventricular fibrillation from artifact sensing in five patients. Two patients had to be resuscitated because of failure to defibrillate. Loss of pacing and loss of sensing were seen in two patients. Only two asymptomatic lead fractures could be diagnosed on routine radiograph. In conclusion, there was a considerable rate of lead failures, especially in epicardial systems. Long-term studies addressing the longevity of ICD leads, mechanisms of their failures, and improved diagnostic facilities are important to further increase the safety of this therapeutic approach.

Defibrillators, Implantable↗
PubMed1995

Double rotation and magic-angle spinning nuclear magnetic resonance study of 27Al: reexamination of the aluminium borate 9Al2O3.2B2O3.

27Al nuclear magnetic resonance spectra of polycrystalline aluminium borate 9Al2O3.2B2O3 have been measured in double rotation at 11.7 and 7.0 T and high-speed magic-angle spinning at 7.0, 9.4, 11.7, 14.1 and 17.6 T. Spinning sidebands from the satellite transitions were observed at 7.0 and 14.1 T. Each of the four structural aluminium sites [Al(IV), Al(V)(1), Al(V)(2) and Al(VI)] are observed, characterised and assigned in the spectra. The obtained parameter set gives a fully consistent interpretation in agreement with the crystal structure of the compound.

Aluminum Compounds↗
PubMed1995

[A bimetal anode with tungsten or rhodium? Comparative studies on image quality and dosage requirement in mammography].

PURPOSE: The impact of different anode materials (tungsten and rhodium) on spatial resolution, image contrast and radiation exposure was studied. MATERIALS AND METHODS: Two mammographic systems providing bimetal x-ray tubes (Mo/W and Mo/Rh) were compared by imaging a breast radiography phantom with additional acrylic plates from 3 to 8 cm thickness. Spatial resolution was evaluated using a line bar pattern. Image contrast was assessed by measuring the ratio of optical densities in a acrylic step-wedge. The entrance dose was measured with a low energy ionisation chamber. RESULTS: The spatial resolution was about 13 lp/mm regardless of the beam quality. The image contrast depended substantially on the thickness. A similar image contrast was found with Mo/Mo, Mo/Rh and Rh/Rh for simulated breast thicknesses of 4 to 6 cm and with Rh/Rh and W/Rh for 7 cm. In comparison to Mo/Mo the dose reduction was significant for Mo/Rh (35%), Rh/Rh (50%) and W/Rh (60%). CONCLUSIONS: Bimetal x-ray tubes provide optimal conditions for screen film mammography of both normal and dense breasts, allowing good contrast and dose reduction by using the adequate anode/filter-combination.

Electrodes↗
PubMed1994

Single-stranded regions in the genome of the Ectocarpus siliculosus virus.

The double-stranded DNA genome of the Ectocarpus siliculosus virus, EsV, is interrupted by numerous single-stranded gaps. We have investigated whether single-stranded regions occur at random or at specific sites. A brief treatment with a single-strand-specific endonuclease dissected the genome into two large fragments, but more extensive treatment produced a spectrum of nuclease-resistant fragments, mainly 10 to 70 kb in size. Native EsV DNA was also used as a substrate for gap-filling DNA synthesis. Restriction analysis revealed that essentially all of the 60 or more SacI restriction fragments became labeled but a few fragments were more intensely labeled than others. The EsV genome may contain a few extended single-stranded regions at fixed sites in addition to numerous single-stranded regions probably occurring at random and varying sites.

Chromosome Mapping↗