Biomedical subjects

C Wolf

Publications and source records attributed to C Wolf.

At least 55 records · Page 3Linked to original sources

PubMed2001

Does carditis have two different etiologies?

Carditis has become the subject of much study and discussion, although its etiology is still controversial. We wished to study the prevalence and possible pathogenetic mechanisms of carditis in a well-defined group of patients. In 664 patients biopsies were taken distal to the squamocolumnar junction (SCJ) and from the endoscopically defined cardia (2 cm below proximal margin of gastric folds). Specimens were stained with hematoxylin and eosin, Alcian blue, and modified Giemsa. Type of mucosa, inflammatory and metaplastic changes, and presence of Helicobacter pylori (Hp) were graded. Most of the patients had a normal appearing SCJ on endoscopy; 19.3% had short columnar segments (1-3 cm). In the first group cardiac/mixed mucosa was found in 71.9% of SCJ biopsies, and carditis (90.6%) was associated with Hp. In the second group, cardiac/mixed mucosa was present in 80.5%. There was a trend for an association between carditis (87.4%) and reflux esophagitis and hiatal hernia. Biopsies from the endoscopically defined cardia rarely contained cardiac/mixed mucosa (12.6%). These findings suggest two etiologies for carditis. In a normal-appearing SCJ carditis is associated with Hp, whereas in an irregular SCJ with short columnar segments/tongues carditis is associated with features of gastroesophageal reflux.

Biopsy↗

PubMed2001

Computer analysis of prolonged lower oesophageal sphincter pressure recordings.

The aim of the study was to validate a recently developed computer program for the analysis of prolonged recordings of lower oesophageal sphincter pressure. Thirty 1-hour stretches were selected from sets of 24-h pressure signals recorded from the pharynx, oesophagus, lower oesophageal sphincter (LOS) and stomach in 10 ambulant patients with gastrooesophageal reflux disease. Three experienced investigators visually analysed end-expiratory LOS pressures and transient lower oesophageal sphincter relaxations (TLOSRs), using published criteria. A computer program was developed for calculation of an end-expiratory pressure curve and detection of TLOSRs using the same criteria. Although the results showed an maximum deviation from the mean of 11.1% and 14.8% for manually calculated LOS pressures and visually detected TLOSRs, respectively only 62.1% of the detected TLOSRs were detected by all three observers. LOS pressure as measured by the computer closely approximated the mean of the LOS pressures calculated by the three observers. Although the total number of TLOSRs was comparable to that assessed by visual analysis, the computer detected only 46% of the TLOSRs detected by each observer and 56.8% of the TLOSRs detected by all observers. It is concluded that automated calculation of end-expiratory LOS pressure is feasible and yields reliable results, whereas automated detection of TLOSRs could not be satisfactorily accomplished. Our study showed that improvement of computer algorithms for TLOSR detection is desirable. However, the previously described criteria for detection of TLOSRs are insufficiently precise; further refinement of these criteria will be necessary to reduce the large discrepancies between the outcome of detection of TLOSRs by computer and by humans, and to reduce the equally large discrepancies between the results of detection by different human observers.

Adult↗

PubMed2001

A multicentre evaluation of a new filtration protocol for leucocyte depletion of high-haematocrit red blood cells collected by an automated blood collection system.

BACKGROUND AND OBJECTIVES: A multicentre trial was set up to evaluate the performance of a new leucodepletion protocol. MATERIALS AND METHODS: Filtration at high haematocrit was started during collection of red blood cell (RBC) products by apheresis with Trima. SAG-M was added after filtration through the filter. Haematocrits and haemoglobin of the filtered RBCs were measured. Residual leucocytes were determined by Nageotte counting. RESULTS: One-hundred and forty seven procedures were carried out. The haematocrit and haemoglobin contents were 57.3 +/- 3.0% and 55.1 +/- 4.3 g/unit, respectively. All products showed low residual leucocyte levels (< or = 0.75 x 106/unit; 99.31% < 1 x 106). CONCLUSION: Immediate, on-line, high-haematocrit filtration of red cells collected on Trima resulted in leucoreduced RBCs, which met the AABB and Council of Europe criteria.

Blood Cell Count↗

PubMed2001

Filtration of methylene blue-photooxidized plasma: influence on coagulation and cellular contamination.

BACKGROUND: Virus inactivation of plasma can be achieved by photodynamic methods in the presence of phenothiazine dyes such as methylene blue (MB). Subsequent filtration may increase the efficacy of virus inactivation and reduce adverse effects of WBC contamination and MB. STUDY DESIGN AND METHODS: This study examined the effect of filtration with three different filters (MBF1, MBF2, and MBF3) on MB concentration, residual cells, coagulation factors, and activation measures of coagulation, fibrinolysis, and complement in MB-treated (1 microM/L) plasma units. RESULTS: Filtration reduced the concentration of MB by > or = 89 percent. WBCs were depleted by 92 percent (MBF1) and >99.9 percent (MBF2 and MBF3). Treatment with MB significantly decreased the coagulation potency from levels in untreated plasma, as measured by thromboplastin time ratio (112 +/- 18% vs. 95 +/- 11%), activated partial thromboplastin time (40 +/- 3 sec vs. 44 +/- 3 sec), thrombin time (16.9 +/- 1.1 sec vs. 18.6 +/- 1.5 sec), factor VIII (1.09 +/- 0.21 U/mL vs. 0.85 +/- 0.13 U/mL), and vWF (0.94 +/- 0.65 U/mL vs. 0.65 +/- 0.24 U/mL). Filtration did not further decrease these values, while factor XI (0.75 +/- 0.22 U/mL vs. 0.37 +/- 0.20 U/mL) and prekallikrein values decreased in MB plasma units filtered with the MBF3. In addition, activated factor XII (0.7 +/- 0.5 microg/L vs. 4.5 +/- 1.0 microg/L) increased. CONCLUSION: WBCs and MB can be eliminated from MB-treated plasma units by filtration. Differences in biocompatibility of the different filters, especially the influence on the contact phase of coagulation, must be taken into consideration.

Blood Coagulation↗

PubMed2001

Epidemiological, clinical, and histological characteristics of intestinal metaplasia at the oesophagogastric junction compared to short segments of columnar-lined oesophagus.

OBJECTIVE: Intestinal metaplasia (IM) close to the oesophagogastric junction (OGJ) has become a focus of research interest against a background of the rising incidence of malignancies in that area. Studies have focused on the presence of IM in short columnar segments (0-3 cm). Recently it has been suggested that IM at the OGJ and IM in short columnar segments may represent different entities. The objective of this current study was to determine the prevalence of IM in these areas and to assess clinical characteristics in order to test the hypothesis that IM at the OGJ and IM in short columnar segments are different entities. METHODS: Six hundred and fifty-eight patients referred for gastroscopy, in whom a columnar lining of 0-3 cm was found, participated in the study. Endoscopic oesophagitis was graded, distances to endoscopic landmarks were measured, and biopsies (antrum, corpus, 'cardia', and immediately distal to the squamocolumnar junction) were taken. Biopsies were stained with haematoxylin & eosin, Alcian Blue (pH 2.5), modified Giemsa for Helicobacter pylori (Hp), and immunohistochemistry in cases of a negative Giemsa. According to endoscopy, patients were categorized as having a normal OGJ (0-1 cm) or having a short columnar segment (1 -3 cm, tongues >1 cm). RESULTS: In this study 77.7% of patients had a normal OGJ (IM-positive 15.1%), and 22.3% had a short columnar segment (IM-positive 29.3%). In the first group, IM was correlated with Hp (P = 0.003) and antral IM (P = 0.002), in the second IM was associated with the presence of a hiatal hernia (P < 0.001) and reflux oesophagitis (P = 0.023). CONCLUSION: These findings suggest that IM at the OGJ is not the same entity as IM in short columnar segments.

Esophageal Neoplasms↗

PubMed2001

Prolonged measurement of lower oesophageal sphincter function in patients with intestinal metaplasia at the oesophagogastric junction.

BACKGROUND AND AIMS: It has been shown that gastro-oesophageal reflux plays a role in the pathogenesis of intestinal metaplasia (IM) limited to the oesophagogastric junction (OGJ), similar to the pathogenesis of IM in long segments of columnar lined oesophagus. The aim of this study was to examine lower oesophageal sphincter (LOS) function by means of prolonged recording in patients with IM limited to a normal appearing OGJ. PATIENTS AND METHODS: Eighteen patients with IM at the OGJ (five females, 13 males; mean age 55.4 years) and 22 patients without IM (nine females, 13 males; mean age 53.9 years) underwent conventional stationary oesophageal manometry. Thereafter, seven hour water perfused manometry with simultaneous pH measurement (probe 5 cm proximal to the LOS) was performed. Swallowing was monitored with a pharyngeal sidehole and LOS pressure was recorded with a Dent sleeve. Patients were studied in the fasted state (three hours) and after a standardised meal (four hours). LOS pressure was analysed using customised software, and the incidence of reflux episodes (pH <4 for at least five seconds) and transient LOS relaxations (TLOSRs) were examined. TLOSRs were judged to be accompanied by reflux if a decrease of 1 pH unit occurred during relaxation. RESULTS: Patients with IM at the OGJ had a higher prevalence of postprandial acid reflux compared with patients without IM. No differences were observed in LOS pressure (pre- and postprandially) or in the prevalence of TLOSRs. However, in the postprandial phase, the rate of TLOSRs accompanied by acid reflux was increased in patients with IM. CONCLUSION: Patients with IM at the OGJ have a higher prevalence of postprandial acid reflux. This is not associated with a higher prevalence of TLOSRs or a decreased LOS pressure but with a higher rate of TLOSRs accompanied by reflux.

Case-Control Studies↗

PubMed2001

Synergistic effect of titanium alloy and collagen type I on cell adhesion, proliferation and differentiation of osteoblast-like cells.

A number of studies have demonstrated the pivotal role of collagen in modulating cell growth and differentiation. In bone, where the extracellular matrix is composed of approximately 85% type I collagen, cellular interaction with matrix components has been shown to be important in the regulation of the osteoblast phenotype. Preservation or enhancement of normal osteoblast function and appositional bone formation after implant placement represents a strategy that can be useful for the purpose of improving osseointegration. In order to further improve biocompatibility, we combined two known favorable compounds, namely the titanium alloy, Ti6A14V, with type I collagen. We assessed the in vitro behavior of primary osteoblasts grown on both fibrillar collagen-coated and tropocollagen-coated Ti6A14V in comparison with uncoated titanium alloy, using an improved adsorption procedure. As parameters of biocompatibility, a variety of processes, including cell attachment, spreading, cytoskeletal organization, focal contact formation, proliferation and expression of a differentiated phenotype, were investigated. Our results demonstrated for the first time that in comparison to uncoated titanium alloy, collagen-coated alloy enhanced spreading and resulted in a more rapid formation of focal adhesions and their associated stress fibers. Growing on collagen-coated Ti6A14V, osteoblasts had a higher proliferative capacity and the intracellular expression of osteopontin was upregulated compared to uncoated titanium alloy. Type I collagen-coated titanium alloy exhibits favorable effects on the initial adhesion and growth activities of osteoblasts, which is encouraging for its potential use as bone graft material. Moreover, collagen type I may serve as an excellent biocompatible carrier for osteotropic factors such as cell adhesion molecules (e.g. fibronectin) or bone-specific growth factors.

Alloys↗

PubMed2001

Is the Zona pellucida thickness of metaphase-II oocytes in an IVF/ICSI program influenced by the patient's age?

Zona pellucida (Z.p.) thickness is believed to be considerably influenced by hormonal stimulation. Assessments of the influence of the patient's age on Z.p. thickness have been at variance. In our study we wanted to investigate, among several other parameters, the age of the patient as a possible factor influencing Z.p. thickness. Prior to intracytoplasmatic sperm injection (ICSI) we determined the mean thickness of the Z.p. of 843 metaphase-II oocytes from 100 patients, which had been obtained after ovarian stimulation in an in vitro fertilization (IVF)/ICSI program. The mean thickness of the Z.p. was significantly positively correlated with the age of the patient (p = 0.000, r = 0.129). When the intraindividual mean values of Z.p. thickness (n = 100) were used, a positive correlation with age (p = 0.174, r = 0.137) remained. However, this correlation was no longer significant. It is concluded that, beside other factors, a thicker Z.p. could be responsible for the possibly lower fertilization rate of older patients in a conventional IVF program.

Adult↗

PubMed2000

Analysis of sulfonated naphthalene-formaldehyde condensates by ion-pair chromatography and their quantitative determination from aqueous environmental samples.

An ion-pair solid-phase extraction (IPE), ion-pair chromatography (IPC) procedure with fluorescence detection for the quantitative analysis of sulfonated naphthalene-formaldehyde condensates (SNFC) was developed, which provides full resolution of SNFC up to a degree of condensation n = 5 and partial resolution up to n = 15. Liquid chromatography-electrospray ionization-mass spectrometry confirmed that SNFC elute in the order of condensation. Response factors in fluorescence detection proved to be mass-constant, thereby allowing us to determine total SNFC amounts. With this IPC method, the weight- and the number-average molecular weights of these high-volume production chemicals (kiloton per annum), used as synthetic tanning agents, concrete plasticizers, and dispersants, can be determined. Recoveries in IPE range from 73 to 85% in river Rhine water and from 79 to 93% in tap water for n = 2 to n = 7 with limits of detection of 3-8 ng/L for individual homologues from 500 mL of water. The IPE-IPC procedure was applied to samples of secondary industrial effluents, river Rhine water, a river bank filtrate, and a groundwater sample. SNFC up to n = 6 were detected in the treated effluents. Total concentrations ranged from 208 micrograms/L in a secondary treated SNFC production effluent to < 1.4 micrograms/L in groundwater. These first analyses suggest a widespread occurrence of the lower oligomers of SNFC in the aquatic environment.

Chromatography, Liquid↗

PubMed2000

Collagen type I-coating of Ti6Al4V promotes adhesion of osteoblasts.

The initial contact of osteoblasts with implant surfaces is an important event for osseointegration of implants. Osseointegration of Ti6Al4V may be improved by precoating of its surface with collagen type I. In this study, the adhesion of rat calvarial osteoblasts to uncoated and collagen type I-coated titanium alloy was investigated over a period of 24 h. Collagen type I-coating accelerates initial adhesion of osteoblasts in the presence of fetal calf serum. One hour after plating, no differences in the percentage of adherent cells between the surfaces investigated were found. Adhesion of osteoblasts to uncoated surfaces was reduced by the GRGDSP peptide by about 70%, whereas adhesion to collagen type I-coated surfaces remained unaffected by treatment of the cells with the peptide. Cell adhesion to coated materials was reduced by about 80% by anti-integrin beta1 antibody. The integrin beta1 antibody did not influence the adhesion to uncoated titanium alloy. The results suggest that osteoblasts adhere to collagen type I-coated materials via integrin beta1 but not by interacting with RGD peptides, whereas adhesion to uncoated titanium alloy is mediated by RGD sequences but not via integrin beta1. Fibronectin does not seem to be involved in the adhesion of osteoblasts to either coated or uncoated titanium alloy.

Adsorption↗

PubMed2000

Single mesodermal cells guide outgrowth of ectodermal tubular structures in Drosophila.

The Drosophila tracheal system, a tubular network, is formed from isolated ectodermal metameres by guided branch outgrowth and branch fusion. Branch outgrowth is triggered by the localized and transient activity of Branchless (Bnl/dFGF). Here, we report the discovery of a mesodermal cell that links the leading cells of outgrowing main branches 2.5 hr before they fuse. This bridge-cell serves as an essential guidance post and needs Hunchback (Hb) activity to exert its function. The bridge-cell provides cues acting in concert with Bnl/dFGF signaling to mediate directed branch outgrowth that ultimately leads to position-specific branch fusion.

Animals↗

PubMed2000

[Pseudostenocardia due to exposure to "electrosmog"].

HISTORY AND REASON FOR ADMISSION: A 44-year-old man had anginal-like complaints. He was convinced that cardiac problems had been caused by electromagnetic fields. INVESTIGATIONS: Apart from hypertension and hyperlipidaemia there were no other significant findings. ECG, ergometry Holter-ECG were normal. EXPERIMENT: We tried to verify with a double-blind provocation test if the patient's complaints had been caused by electromagnetic fields. The patient was exposed to an electric instrument without being aware whether it was switched on or off. He was questioned about his perception of the presence of an electric current. CONCLUSION: The results of the test showed that there was no causal relation between the patient's angina-like-symptoms and electromagnetic fields. The phenomenon of electrosensitivity was probably caused by psychological mechanisms.

Adult↗

PubMed2000

Compared effects of cholesterol and 7-dehydrocholesterol on sphingomyelin-glycerophospholipid bilayers studied by ESR.

The ESR of 7- and 16-doxylstearic spin-labeled fatty acids (7NS and 16NS, respectively) reveal the distinct influence of cholesterol or cholesterol precursor analogue, delta7-dehydrocholesterol, on the molecular ordering and the fluidity of lipid mixtures containing sphingomyelin (SM). The phase-separation of sphingomyelin domains mixed within fluid glycerophospholipids (phosphatidylethanolamine and phosphatidylserine) can be followed by ESR as a function of the temperature and in the presence of sterols [cholesterol (CHOL) or 7-dehydrocholesterol (DHCHOL)]. The time scale of spin-label exchange among phases is appropriate to follow the occurrence of the specific sphingomyelin/sterol association forming liquid ordered (Lo) microdomains which separate from the fluid surrounding phase Lalpha. Sphingomyelin embedded within the fluid bilayer associates with both sterols below 36 degrees C to give a phase Lo traceable by ESR in the form of a highly anisotropic component. Above 36 degrees C, the contribution in the ESR spectrum, of the Lo phase formed by 7-dehydrocholesterol with sphingomyelin is reduced by contrast with cholesterol forming a temperature-stable liquid ordered phase up to 42 degrees C. The consequences of this destabilization of the SM/sterol microdomains are envisioned in the biosynthesis defect where the precursor 7-dehydrocholesterol substitutes, for a significant part, the embryonic cell cholesterol.

Animals↗

PubMed2000

Phenylketonuria and hyperphenylalaninemia in eastern Germany: a characteristic molecular profile and 15 novel mutations.

Phenylketonuria (PKU) is an important error of amino acid metabolism which results in most patients from phenylalanine hydroxylase (PAH) deficiency. PKU displays a marked genotypic heterogeneity both within and between different populations. The aim of this study was to establish the genotypic spectrum of PKU in eastern Germany, and to compare this to the distribution of mutations in western Germany. The study population included 302 patients in 290 families who were followed at treatment centers in Berlin, Leipzig and Jena. The study showed marked genotypic variability with a total of 75 mutations, including 15 that have so far not been described (eleven missense mutations, one splicing mutation, and three small deletions). One of these novel mutations, E183Q, occurred in cis to a R408W mutation. In the non-immigrant eastern German population, the frequency of R408W accounted for 40.1% of the PKU alleles. In the immigrant Turkish population of the former West Berlin, the most prevalent mutation was IVS10-11G>A (57%). There was a marked difference of the genotypic spectrum between the population studied here and the data reported from the western part of the country.

Amino Acid Substitution↗

PubMed2000

Investigation of capillary electrochromatography with brush-type chiral stationary phases.

Fused-silica capillaries (100 microm ID) were packed with the (3R, 4S)-Whelk-O chiral stationary phase (CSP) bonded on 3.0 microm silica particles. The enantiomers of 41 neutral analytes containing stereogenic centers, axes or planes were examined by packed capillary electrochromatography. More than 30 of these were cleanly resolved, owing to the selectivities and efficiencies afforded by this CSP. High reproducibility with no indication of diminished performance was observed using the same capillary for hundreds of runs (including intermediate change of the buffer system) over a period of several weeks. Acetate, 2-(N-morpholino)ethanesulfonic acid, or phosphate buffers, each modified with either acetonitrile or methanol, were used as mobile phases. The influence of buffer concentration, modifier amount, temperature, applied voltage, and pH on performance of the brush-type CSP was investigated.

Buffers↗

PubMed2000

Quantification of the metal distribution in metallothioneins of the human liver by HPLC coupled with ICP-AES.

Fractions containing metallothioneins (MT's), extracted from the liver cytosol of humans, were analysed to determine the complete distribution pattern of the metals copper, cadmium and zinc. Samples of cirrhotic livers which had come from organs removed during transplantation were examined for differences in the trace-element binding pattern. After the extraction of supernatants from the tissue samples, membrane ultrafiltration of the cytosolic solution was carried out to separate all high-molecular proteins with molecular weights >100 kDa. This procedure retains the metal content of the MT's in its initial form, in contrast to the often-used heat treatment of samples, which changes the copper distribution significantly. The MT's themself were isolated using size exclusion and anion exchange chromatography. Their metal content was determined simultaneously on-line by combination with an ICP-AES as element detector. Calibration of the procedure was performed by means of a column by-pass-injection of elemental standards into the separation system. The MT content in the samples was calculated using the determined metal concentrations and the generally accepted metal/protein ratios for Cu (12:1), Cd (7:1) and Zn (7:1). These values were compared with values resulting from a 109Cd-saturation-assay. When various liver samples of different pathogenesis were compared, the highest level of Cu-MT was found in primary biliary cirrhosis.

Animals↗

PubMed2000

Evaluation of hydrophobic/hydrophilic balance of bile acids by comparative molecular field analysis (CoMFA).

A comparative molecular field analysis (CoMFA) model, employing standard steric and electrostatic fields, is able to predict the hydrophobic/hydrophilic balance, expressed as reverse-phase HPLC capacity factor, for a series of both naturally occurring and semi-synthetic bile acids. The very high values of cross-validated R(2) (Q(2)) demonstrate that the CoMFA method can give useful information on the hydrophobic balance of newly synthesized bile acids.

Bile Acids and Salts↗

PubMed2000

Correlation of the LET-dependent TL-response of LIF:Mg,Ti TL-dosemeters and gentoxic endpoints after proton irradiation.

The high temperature ratio (HTR) method using LiF:Mg,Ti thermoluminescent dosemeters allows in addition to the measurement of absorbed dose, the evaluation of the biological effectiveness of radiation. In order to analyse the correlation of the measured parameter HTR and gentoxic endpoints irradiation of cell cultures and TLDs were performed in a 62 MeV proton beam. The gentoxic effects respectively the relative biological effectiveness RBE, show an excellent correlation with the HTR due to a similar dose and LET-dependent behaviour.

Animals↗