Biomedical subjects

K W Wenzel

Publications and source records attributed to K W Wenzel.

At least 19 recordsLinked to original sources

PubMed2001

Changes in xylosyltransferase activity and in proteoglycan deposition in bleomycin-induced lung injury in rat.

Several lines of evidence support the hypothesis of the involvement of altered proteoglycan deposition in the development of lung diseases. UDP-D-xylose: core protein beta-D-xylosyltransferase (UDP-xylosyltransferase; EC 2.4.2.26) is a key enzyme for the glycosylation of proteoglycan core proteins. This study examined the catalytic activity of UDP-xylosyltransferase in lung tissue and in isolated fibroblasts, as well as the deposition of the proteoglycans versican, biglycan and decorin in rat lung tissue during bleomycin-induced lung injury. Rats were given, endotracheally, a single dose of bleomycin. Deposition of proteoglycans in lung tissue was assessed by immunohistochemistry and the catalytic activity of xylosyltransferase was determined with an acceptor peptide of the sequence Q-E-E-E-G-S-G-G-G-Q-G-G as a substrate. The results show coincidence of increasing xylosyltransferase activities in lung tissue with accumulation of versican at alveolar entrance rings and in fibrotic regions in close proximity to alpha-smooth muscle actin-positive cells. In contrast, no changes in biglycan and decorin deposition in fibrotic lungs were observed, except for decorin in alveolar type II pneumocytes and alveolar macrophages. Bleomycin treatment of isolated rat lung fibroblasts resulted in a concentration-dependent increase of xylosyltransferase activity up to 2 mU bleomycin x mL(-1). The data suggest a participation of myofibroblasts with increased xylosyltransferase activities in accumulation of versican in fibrotic foci of injured lung tissue at the early stages of development of lung fibrosis.

Animals↗

PubMed2000

Purification and some properties of UDP-xylosyltransferase of rat ear cartilage.

UDP-xylosyltransferase (UDP-D-xylose:proteoglycan core protein beta-D-xylosyltransferase EC 2.4.2.26) initiates the formation of chondroitin sulfate in the course of proteoglycan biosynthesis. The enzyme catalyzes the transfer of D-xylose from UDP-D-xylose to specific serine residues in the core protein. A procedure for purification of xylosyltransferase from rat ear cartilage was developed which includes ammonium sulfate fractionation, chromatography on heparin-agarose, on Sephacryl S300 and finally a substrate affinity chromatography applying the dodeca peptide Q-E-E-E-G-S-G-G-G-Q-G-G. The specific activity of the purified enzyme was about 420 mU per mg protein. The purification factor was about 26.000 with 27% yield. In SDS-polyacrylamide gel electrophoresis, the highly purified enzyme is homogeneous and yields only a single distinct band of 78 kDa. An apparent molecular mass of 71 kDa was determined for the native enzyme. These data suggest a monomeric structure for the enzyme. Xylosyltransferase activity was found to depend essentially on the presence of divalent metal ions. The K(m) value for UDP-D-xylose was determined to 6.5 micromol/l and for the dodeca peptide Q-E-E-E-G-S-G-G-G-Q-G-G as xylose acceptor to 8 micromol/l.

Amino Acid Sequence↗

PubMed1999

Characterisation of caveolins from cartilage: expression of caveolin-1, -2 and -3 in chondrocytes and in alginate cell culture of the rat tibia.

This study was performed to determine if rat articular chondrocytes express caveolin, the structural protein of caveolae, and to determine differences in the distribution of the caveolin subtypes 1, 2 and 3 in knee joints of newborn and adult rats. All three subtypes of caveolin were detected in adult cartilage by immunocytochemical staining. In newborn rats, only caveolin-1 was found in the hyaline cartilage. Caveolin-1, -2 and -3 messenger RNA and protein were also detected in chondrocyte cell cultures. Ultrastructural investigations of cell culture and cartilage tissue revealed the presence of caveolae at the plasma membrane of chondrocytes. These findings represent the first report on the different expression of caveolin isoforms, in particular the expression of the muscle cell-specific caveolin-3 in chondrocytes. There is evidence that caveolin-2 and -3 are upregulated during growth and development of articular cartilage, suggesting a role for caveolins in chondrocyte differentiation.

Alginates↗

PubMed1999

Home self-assessment and self-treatment of obsessive-compulsive disorder using a manual and a computer-conducted telephone interview: replication of a UK-US study.

BACKGROUND: This open study replicates and extends previous pilot work with BT STEPS, a self-therapy system to assess and treat obsessive-compulsive disorder (OCD) through exposure and ritual prevention. METHOD: 21 OCD patients entered this open trial, using a self-guiding manual and any Touch-Tone telephone to access computer-driven interviews via an Interactive Voice Response system. The patients also used the system to rate progress on rating scales. RESULTS: The results support those of the previous open study. Of the 21 patients, 16 (76%) completed self-assessment over a mean of 21 days. Of these, 10 patients (48%) went on to do 2 or more exposure and ritual prevention sessions over a mean of 64 days; they improved significantly on OCD symptoms, as much as is usual with serotonin reuptake inhibitor medication, and in mood and work/social adjustment. Improvement was predicted by baseline motivation and by rapid completion of self-assessment with BT STEPS, even though self-assessment alone was not therapeutic. CONCLUSION: The significant improvement in the intent-to-treat analysis was due to the subgroup of patients (48% of those who began BT STEPS) who went beyond self-assessment to do exposure and ritual prevention self-therapy at home guided by BT STEPS. A controlled trial is now needed.

Adult↗

PubMed1998

Transforming growth factor-beta1-induced activation of the Raf-MEK-MAPK signaling pathway in rat lung fibroblasts via a PKC-dependent mechanism.

In fibroblasts transforming growth factor-beta1 (TGF-beta1) regulates cell proliferation and turnover of macromolecular components of the extracellular matrix. Here, intracellular signaling events in growth-inhibited embryonic rat lung fibroblasts (RFL-6) upon stimulation with TGF-beta1 were investigated. TGF-beta1 rapidly induced the activation of c-Raf-1, MEK-1, and MAPK p42 and p44. The activation of this pathway by TGF-beta1 did not depend on autocrine platelet-derived growth factor (PDGF) or basic fibroblast growth factor (bFGF). Inhibition of the binding of growth factors to their tyrosine kinase receptors did not affect MAPK activation by TGF-beta1. Ras activation by TGF-beta1 was significantly lower compared to the activation by PDGF or bFGF. The intracellular transduction of the TGF-beta1 signal was completely suppressed by depletion or inhibition of protein kinase C (PKC). It is shown that calcium-dependent isoforms of PKC are required for MAPK activation by TGF-beta1.

Animals↗

PubMed1998

Proteinases and proteinase inhibitors during the development of pulmonary fibrosis in rat.

Changes in the activities of several proteinases and their inhibitors were investigated during the development of bleomycin-induced pulmonary fibrosis in rat. Studies on the proteinase-anti-proteinase-ratio may contribute to the understanding of the mechanism of the development of pulmonary fibrosis and may help to develop therapeutic strategies to prevent tissue damage by proteolytic attack. In the acute inflammatory period the activity of metalloelastase in lung tissue increased by about 10-fold. The time course of changes in the activity of 72 kD gelatinase indicates that this gelatinase accounts at least partially for the elastolytic activity. Elastase inhibitory activity in lung tissue showed maxima at days 1 and 5 and high levels in the fibrotic phase. The increase of the elastase inhibitory activity at the beginning of the fibrotic period corresponds with elevated activity of alpha 2-macroglobulin. Alveolar fluid and alveolar macrophages did not contain elastase activity but contained high elastase inhibitory activity. During the period of chronic inflammation, the activities of the cathepsins L, B, H and S in lung tissue and in isolated alveolar macrophages were found to be strongly increased.

Animals↗

PubMed1998

Loss of caveolin expression in type I pneumocytes as an indicator of subcellular alterations during lung fibrogenesis.

Caveolin is a major structural protein of caveolae, also known as plasmalemmal vesicles, which are particularly abundant in type I pneumocytes and capillary endothelial cells of lung parenchyma. Here we demonstrate that caveolin expression in the alveolar epithelium of rats and mini pigs is strikingly downregulated after irradiation-induced lung injury. Indirect immunoperoxidase staining with polyclonal anti-caveolin antibodies, confirmed by double fluorescence studies with type I cell-specific monoclonal anti-cytokeratin antibodies or lectins, revealed a dramatic loss of caveolin immunoreactivity in type I pneumocytes. In contrast, caveolin expression increased in endothelial cells. Immunoblotting of lung homogenates from normal and irradiated rats using specific anti-caveolin antibodies confirmed the presence of caveolin in normal tissue and its marked decrease of expression in fibrotic tissue. The loss of caveolin as an important structural protein of caveolae in alveolar epithelial cells may be an early indicator of serious type I cell injury during fibrogenesis. The increase of caveolin immunoreactivity in endothelia of blood vessels may indicate that different types of caveolae and/or different regulatory mechanisms of caveolin expression exist.

Animals↗

PubMed1998

Loss of immunoreactivity for RTI40, a type I cell-specific protein in the alveolar epithelium of rat lungs with bleomycin-induced fibrosis.

After lung injury, the epithelial cells lining the alveolar surface in rat lung show an altered distribution of several membrane proteins. Pulmonary fibrosis was induced by intratracheal administration of bleomycin into the lung of rats and the distribution of RTI40, a recently detected alveolar epithelial type I cell antigen, was examined, as well as the relationship between RTI40 and a type I cell-specific antigen recognized by the monoclonal antibody MEP-1 and the type I cell-binding lectin Bauhinia purpurea in serial sections and double stainings. Loss of RTI40 protein was observed in fibrotic lungs, particularly in areas with obliteration of alveoli. Pre-embedding immunoelectron microscopy confirmed this observation by detection of RTI40 protein in the alveolar lumen. Western blot analysis revealed elevated levels of RTI40 in the bronchoalveolar fluid of bleomycin-treated rats with a maximum at day 7 after treatment. Twenty-eight days after bleomycin application, the bronchoalveolar fluid contained three times the amount of RTI40 x mg protein(-1) of control lungs, as determined by semiquantitative dot blot. These results suggest RTI40 as a tool for the evaluation of alveolar epithelial type I cell behaviour during re-epithelialization processes.

Animals↗

PubMed1998

Home self-assessment of obsessive-compulsive disorder. Use of a manual and a computer-conducted telephone interview: two UK-US studies.

BACKGROUND: Two studies tested whether subjects with obsessive-compulsive disorder could successfully use BT STEPS, a computer-aided system, to perform self-assessment for self-treatment of obsessive-compulsive disorder by exposure and ritual prevention. METHOD: Subjects were given a self-guiding manual and could use a touch-tone telephone to access computer-controlled Interactive Voice Response interviews at their convenience from home. Using the BT STEPS system, patients rated themselves and worked out a plan for individually tailored self-exposure therapy. RESULTS: Outcomes were similar in the two studies. Of the 63 subjects who used BT STEPS, 84% completed the self-assessment module. Most calls were made outside usual office hours. As expected, subjects did not improve merely by completing self-assessment. However, completion of self-assessment predicted later improvement with self-exposure therapy. CONCLUSIONS: Most subjects successfully completed self-assessment using BT STEPS from their homes. DECLARATION OF INTEREST: BT STEPS is a trademark of Pfizer, Inc. I.M.M., L.B. and J.H.G. have a financial interest in BT STEPS.

Adult↗

PubMed1998

Self-administered psychotherapy for depression using a telephone-accessed computer system plus booklets: an open U.S.-U.K. study.

OBJECTIVE: To evaluate the efficacy and acceptability of a self-help program for mild-to-moderate depression that combined treatment booklets and telephone calls to a computer-aided Interactive Voice Response (IVR) system. METHOD: In an open trial, 41 patients from Boston, Massachusetts; Madison, Wisconsin; and London, England, used COPE, a 12-week self-help system for depression. COPE consisted of an introductory videotape and 9 booklets accompanied by 11 telephone calls to an IVR system that made self-help recommendations to patients based on information they entered. RESULTS: All 41 patients successfully completed the self-assessment in the booklets and telephone calls; 28 (68%) also completed the 12-week self-help program. Hamilton Rating Scale for Depression (HAM-D) and Work and Social Adjustment scores improved significantly (41% and 42% mean reduction in the intent-to-treat sample, respectively, p < .001). Eighteen (64%) of the 28 completers were considered responders on the basis of > or = 50% reduction in their HAM-D scores. There was a higher percentage of completers in the pooled U.S. sites (82% vs. 43%), and U.S. completers improved more than those in the United Kingdom (73% vs. 43% were responders). Most (68%) of the calls were made outside usual office hours, Monday-Friday, 9:00 a.m. to 5:00 p.m. Expectation of effectiveness and time spent making COPE calls (more treatment modules) correlated positively with improvement over 12 weeks. Mean call length for completers was 14 minutes. CONCLUSION: A self-help system comprised of a computer-aided telephone system and a series of booklets was used successfully by people with mild-to-moderate depression. These preliminary results are encouraging for people who cannot otherwise access ongoing, in-person therapy.

Adult↗

PubMed1997

Autophosphorylation-inactivation site of hexokinase 2 in Saccharomyces cerevisiae.

Hexokinase 2 from Saccharomyces cerevisiae is phosphorylated in vivo at serine-15 [Kriegel et al. (1994) Biochemistry 33, 148-152] and undergoes ATP-dependent autophosphorylation-inactivation in vitro when incubated in the presence of D-xylose [Fernandez et al. (1988) J. Gen. Microbiol. 134, 2493-2498]. This study identifies the site of inactivation by autophosphorylation as serine-158 by observation of a single tryptic peptide difference, peptide sequencing, and size determination by mass spectrometry. Mutation of serine-158 to alanine and cysteine, respectively, prevents autophosphorylation and causes a drastic decrease of the catalytic activity while mutational change to glutamate results in a complete loss of enzyme activity. The catalytically active mutant enzymes display an increased affinity for glucose and exhibit higher K(M) with respect to MgATP. Phosphoserine/phosphothreonine-specific protein phosphatase-2A completely reverses the autophosphorylative inactivation of the wild-type enzyme.

Alanine↗

PubMed1997

Transforming growth factor-beta1 induces activation of Ras, Raf-1, MEK and MAPK in rat hepatic stellate cells.

The transdifferentiation of hepatic stellate cells into myofibroblast-like cells and the proliferation of the transdifferentiated cells are controlled by TGF-beta1. Little is known about the intracellular signal transducers of TGF-beta1. In this paper we show that in cultured hepatic stellate cells TGF-beta1 induces activation of Ras, Raf-1, MEK and MAPK p42 and p44. The activation of MAPK depends on the activation of MEK. Our data exclude that the observed effects are mediated by a bFGF or PDGF autocrine loop.

Animals↗

PubMed1997

Cellular distribution of c-Jun and c-Fos in rat lung before and after bleomycin induced injury.

C-Jun and c-Fos transcription factors have been associated with enhanced cellular proliferation. We studied their cellular distribution in normal and fibrotic rat lung. Pulmonary fibrosis was induced by intratracheal administration of bleomycin. In normal rat lung, c-Jun and c-Fos are present in alveolar macrophages and type II pneumocytes, in the bronchiolar epithelium and in smooth muscle cells of bronchioli and blood vessels. Subcellular fractionation of proteins revealed a predominant presence of both c-Jun and c-Fos in the heavy membrane fraction containing mitochondria and secretory granules. This was confirmed by immunoelectron microscopy, which also revealed a different localization of c-Jun and c-Fos in different cell types. Whereas in type II pneumocytes and in macrophages cytoplasmic c-Jun and c-Fos is associated with mitochondria, in Clara cells of the bronchial epithelium only secretory granules contain c-Jun and c-Fos. In addition, c-Jun is strongly present in the nuclear fraction. In the fibrotic rat lung c-Jun and c-Fos are located in the same cell types as in control lungs. In addition, fibroblasts contain c-Jun and c-Fos in areas of proliferation whereas in areas of complete fibrosis there is only a very weak expression of c-Jun and c-Fos.

Animals↗

PubMed1996

Upregulation of gap junction protein connexin43 in alveolar epithelial cells of rats with radiation-induced pulmonary fibrosis.

The degree of immunoreactive connexin43 (C x 43) in rat lung was evaluated during the development of radiation-induced pulmonary fibrosis in rat by a double immunofluorescence technique using polyclonal antisera to Cx43 and monoclonal antibodies to cytokeratins on cryostat sections. In normal rat lungs, Cx43 was detected in pneumocytes type II and I, in large blood vessel endothelia, in peribronchial smooth muscle cells, and in some peribronchial and perivascular interstitial cells. As early as 1 week after irradiation, enhanced immunoreactivity for Cx43 in the epithelial cells was detected. In severely injured lungs (about 3 months after irradiation), Cx43 was found also in the cytoplasm of type II pneumocytes. These findings were confirmed by western blot data. Western blot analysis also revealed increased phosphorylation of Cx43. It remains to be investigated whether the increased content of Cx43 in irradiated rat lung may be due to an enhanced number of gap junctions between type I and II alveolar epithelial cells.

Actins↗

PubMed1996

Disturbances of thyroid function tests by drugs.

Commonly prescribed drugs can variously cause changes in measuring serum T3 and T4 concentrations. Thus spuriously normal thyroid hormone levels may result in moderate hypo- or hyperthyroidism, or the influence of pharmacological substances may lead to a false diagnosis of thyroid disease in euthyroid subjects. On the other hand numerous pharmacological agents, especially those interacting with neurotransmitters, may influence TSH secretion, too. While generally such drug-induced abnormal thyroid tests do not correspond to clinical features of thyroid dysfunction, iodine containing drugs, especially amiodarone, may result in overt thyroid disease.

Amiodarone↗

PubMed1995

Immunohistochemical evidence for loss of ICAM-1 by alveolar epithelial cells in pulmonary fibrosis.

ICAM-1 is an intercellular adhesion molecule of the immunoglobulin supergene family involved in adherence of leukocytes to the endothelium and in leukocytic accumulation in pulmonary injury. In the current study, the antigen retrieval technique was used to detect ICAM-1 immunohistochemically in paraffin sections of lungs from human, mouse and rat as well as in bleomycin- or radiation-induced fibrotic lungs from rat and human. In normal lung tissue, the expression of ICAM-1 on alveolar type I epithelial cells is stronger than on alveolar macrophages and on endothelial cells. Preembedding immunoelectron microscopy of normal rat, mouse and human lung samples revealed selective ICAM-1 expression on the surface of type I alveolar epithelial cells and, to a lesser extent, on the pulmonary capillary endothelium and on alveolar macrophages. In fibrotic specimens, both focal lack and strengthening of immunostaining on the surface of type I cells was found. Alveolar macrophages were found focally lacking ICAM-1 immunoreactivity. In some cases, rat type II pneumocytes exhibited positive immunoreactions for ICAM-1. Immunoelectron microscopy with preembedded rat lungs (bleomycin-exposed cases) confirmed the altered ICAM-1 distribution at the alveolar epithelial surface. In the alveolar fluid of fibrotic rat lungs, in contrast to that from untreated controls, soluble ICAM-1 was detected by western blot analysis.

Animals↗

PubMed1995

Changes in epitope exposition of apolipoprotein A-I on the surface of high density lipoproteins after phospholipase A2 treatment.

The immunoreactivity of high density lipoprotein (HDL) modified by treatment with porcine pancreatic phospholipase A2 (PLA2) was studied in a competitive radioimmunoassay using 6 different monoclonal apolipoprotein (apo) A-I antibodies. The competition tests have shown that after PLA2 treatment the immunoreactivity of selected epitopes of apo A-I changed in different ways. While the binding behavior of two epitopes remained unchanged, three epitopes exhibited decreased immunoreactivities after phospholipids hydrolysis. In contrast to the latter epitopes, the immunoreactivity of an epitope located on the cyanogen bromide fragment 4 of apo A-I increased with the degree of lipolysis. A loss of apo A-I from HDL as a consequence of PLA2-treatment did not occur as shown by the determination of the apo A-I concentration in HDL before and after treatment with PLA2. Using overlapped synthetic decapeptides it could be shown that the epitope increasingly exposed on the particle surface of PLA2-modified HDL consists of the amino acid residues 162-173 and 212-229. These residues are characterized by high hydrophobic indices as determined by hydropathy analysis. Furthermore, these regions belong partially to the proposed receptor-binding domain of apo A-I. Thus, an increased exposition of this epitope might result in elevated cellular binding affinities of HDL occurring after modification of lipoproteins by PLA2-treatment.

Amino Acid Sequence↗

PubMed1994

[Therapeutic results of radioiodine therapy of hyperthyroid thyroid gland diseases].

PATIENTS AND METHODS: The result of radioiodine treatment administered to 126 patients with hyperthyroidism between 1986 and 1991 were analysed retrospectively. The indications for radioiodine treatment were single hyperfunctioning nodules (n = 47), multinodular goitre (n = 33), diffuse goitre (n = 19) and Graves' disease (n = 27); the respective doses of 131I, calculated with the Doering and Kramer formula, were 300 Gy (30,000 rad), 150 to 200 Gy (15,000 to 20,000 rad), 100 to 120 Gy (100,000 to 120,000 rad) and 100 Gy (100,000 rad). The uptake of radioiodine was measured on a daily basis and in the case of 46 patients (36.5%) additional treatment given on the third day of treatment. RESULTS: For the patients undergoing regular follow-up, data were collected in 1992, at least six months post-therapy. Evaluation revealed a total applied dose of 131I of 20 +/- 12.4 mCi (median +/- SD) per patient. non-response to treatment making hospitalisation and renewed therapy necessary was observed in 1.6% of the group. In only two further patients did scintigraphy reveal compensated toxic adenoma. In 36% of patients with single hyperfunctioning nodules, 21% of those with multinodular goitre, 53% of those with diffuse goitre and 56% of those with Graves' disease hyperthyroidism was observed. In the great majority of cases, hypothyroidism occurred in the first year following treatment.

Adult↗