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Dive into the research topics where Christian Virchow is active.

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Featured researches published by Christian Virchow.


British Journal of Pharmacology | 2003

Stimulation of P2 purinergic receptors induces the release of eosinophil cationic protein and interleukin-8 from human eosinophils

Marco Idzko; Elisabeth Panther; Hinrich C. Bremer; Stephan Sorichter; Werner Luttmann; Christian Virchow; Francesco Di Virgilio; Yared Herouy; Johannes Norgauer; Davide Ferrari

Extracellular nucleotides are the focus of increasing attention for their role as extracellular mediators since they are released into the extracellular environment in a regulated manner and/or as a consequence of cell damage. Here, we show that human eosinophils stimulated with different nucleotides release eosinophil cationic protein (ECP) and the chemokine interleukin 8 (IL‐8), and that release of these two proteins has a different nucleotide requirement. Release of ECP was triggered in a dose‐dependent manner by ATP, UTP and UDP, but not by 2′‐&3′‐o‐(4‐benzoyl‐benzoyl)adenosine 5′‐triphosphate (BzATP), ADP and α,β‐methylene adenosine 5′ triphosphate (α,β‐meATP). Release of IL‐8 was triggered by UDP, ATP, α,β‐meATP and BzATP, but not by UTP or ADP. Pretreatment with pertussis toxin abrogated nucleotide‐stimulated ECP but not IL‐8 release. Release of IL‐8 stimulated by BzATP was fully blocked by the P2X7 blocker KN‐62, while release triggered by ATP was only partially inhibited. IL‐8 secretion due to UDP was fully insensitive to KN‐62 inhibition. Priming of eosinophils with GM‐CSF increased IL‐8 secretion irrespectively of the nucleotide used as a stimulant. It is concluded that extracellular nucleotides trigger secretion of ECP by stimulating a receptor of the P2Y subfamily (possibly P2Y2), while, on the contrary, nucleotide‐stimulated secretion of IL‐8 can be due to activation of both P2Y (P2Y6) and P2X (P2X1 and P2X7) receptors.


FEBS Letters | 2000

P2 purinergic receptors of human eosinophils: characterization and coupling to oxygen radical production

Davide Ferrari; Marco Idzko; Stefan Dichmann; Daniela Purlis; Christian Virchow; Johannes Norgauer; Paola Chiozzi; Francesco Di Virgilio; Werner Luttmann

Extracellular nucleotides elicit multiple responses in eosinophils but no information on expression of purinergic receptors in these cells is available so far. In the present study we show that human eosinophils express the following P2Y and P2X subtypes: P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, and P2X1, P2X4, P2X7, whose stimulation results in intracellular Ca2+ increase and production of large amounts of reactive oxygen intermediates. These events are stimulated or inhibited, respectively, by P2 receptor agonists or antagonists.


Strahlentherapie Und Onkologie | 2007

6-Year Experience of Concurrent Radiochemotherapy with Vinorelbine Plus a Platinum Compound in Multimorbid or Aged Patients with Inoperable Non-Small Cell Lung Cancer

Sabine Semrau; Anette Bier; Ulrike Thierbach; Christian Virchow; Peter Ketterer; Gunther Klautke; Rainer Fietkau

Background and Purpose:Although poor-risk patients represent no minority in inoperable non-small cell lung cancer (NSCLC), there is little experience with concurrent radiochemotherapy (RCT) in this group. Here, the authors report on the feasibility and efficacy of RCT with vinorelbine plus carboplatin or cisplatin in NSCLC patients with comorbidities and poor general health or advanced age.Patients and Methods:A total of 66 patients (ten women, 56 men, median age 68 years) with inoperable NSCLC and an increased risk of treatment side effects (WHO performance score of 2–3; cardiac, pulmonary or renal failure or extensive weight loss before treatment, or an age of 71–78 years) were treated with vinorelbine 12.5 mg/m2 on days 1, 8, 15, 29, 36, and 43 in combination with either carboplatin 70 mg/m2 (n = 59) or cisplatin 20 mg/m2 (n = 7) on days 1–5 and 29–33 in addition to receiving conventional fractionated radiotherapy with doses of up to 63 Gy (90% isodose).Results:62 of 66 patients (94%) reached the 90% level of the prescribed radiation dose, and 41/66 patient (62%) received at least two cycles of the platinum compound and four cycles of vinorelbine. The following hematologic side effects (CTC classification [Common Toxicity Criteria]) were observed: grade 3 (12%) and grade 4 (15%) thrombocytopenia, grade 3 (38%) and grade 4 (4%) leukocytopenia, and anemia requiring transfusion (26%). Other side effects (CTC) included grade 3 (3%) and grade 4 (2%) esophagitis and grade 3 pneumonitis (3%). The response rates were as follows: complete remission 18%, partial remission 56%, stable disease 21%, and progressive disease 5%. The cumulative survival rates were 53%, 24%, and 8% at 12 months, 24 months, and 5 years, respectively.Conclusion:After including a larger group of patients than in 2003 and following the patients for several years, the authors determine that concurrent RCT consisting of vinorelbine plus a platinum compound and conventional fractionated radiotherapy can be carried out with manageable toxicity, even in this negatively selected population of patients. Their survival rates were comparable to those achieved in other studies with simultaneous RCT.Hintergrund und Ziel:Obwohl Patienten mit erhöhten Behandlungsrisiken keine Minderheit in der Gruppe der inoperablen nichtkleinzelligen Bronchialkarzinome (NSCLC) darstellen, sind die Erfahrungen mit einer simultanen Radiochemotherapie (RCT) gering. Die Autoren berichten über die Durchführbarkeit und Effektivität der RCT mit Vinorelbin und Carboplatin oder Cisplatin bei komorbiden Patienten in reduziertem Allgemeinzustand oder fortgeschrittenem Alter.Patienten und Methodik:Insgesamt wurden 66 Patienten (zehn Frauen, 56 Männer, medianes Alter 68 Jahre) mit inoperablem NSCLC und erhöhten Behandlungsrisiken (WHO-Performance-Score 2/3; kardialer, pulmonaler oder renaler Insuffizienz oder ausgeprägtem prätherapeutischem Gewichtsverlust oder in einem Alter von 71–78 Jahren) mit Vinorelbin 12,5 mg/m2 an den Tagen 1, 8, 15, 29, 36 und 43 und Carboplatin 70 mg/m2 (n = 59) oder Cisplatin 20 mg/m2 (n = 7) d1–5 und 29–33 sowie einer konventionell fraktionierten Radiotherapie bis 63 Gy (90%-Isodose) behandelt.Ergebnisse:62 von 66 Patienten (94%) erreichten ein Dosislevel von 90% der zu applizierenden Strahlendosis, 41/66 Patienten (62%) erhielten mindestens zwei Kurse des Platinderivats und vier Kurse Vinorelbin. Folgende hämatologische Nebenwirkungen (CTC-Klassifikation [Common Toxicity Criteria]) wurden beobachtet: Thrombozytopenie Grad 3 (12%) und Grad 4 (15%), Leukozytopenie Grad 3 (38%) und Grad 4 (4%) sowie transfusionsbedürftige Anämie (26%). Andere Nebenwirkungen bestanden aus Ösophagitiden Grad 3 (3%) und Grad 4 (2%) sowie Pneumonitis Grad 3 (3%). Die Ansprechraten waren wie folgt: komplette Remission 18%, partielle Remission 56%, stabile Erkrankung 21% und Krankheitsprogression 5%. Das kumulative Überleben betrug nach 12 Monaten 53%, nach 24 Monaten 24% und nach 5 Jahren 8%.Schlussfolgerung:Auch nach Einschluss einer größeren Patientengruppe als 2003 und nach einer langen Nachbeobachtungszeit wird eine simultane RCT mit Vinorelbin und einem Platinderivat sowie einer konventionell fraktionierten Radiotherapie mit einer beherrschbaren Toxizität bei diesem negativ selektionierten Patientengut für durchführbar erachtet. Die Überlebensdaten erreichen die in anderen Studien durch eine simultane RCT erzielten Ergebnisse.


Journal of Cellular Physiology | 2001

Functional characterization of P2Y and P2X receptors in human eosinophils

Marco Idzko; Stefan Dichmann; Elisabeth Panther; Davide Ferrari; Yared Herouy; Christian Virchow; Werner Luttmann; Francesco Di Virgilio; Johannes Norgauer

Activation of purinoceptor by ATP induces in eosinophils various cell responses including calcium transients, actin polymerization, production of reactive oxygen metabolites, CD11b‐expression, and chemotaxis. Here, the effect of ion channel‐gated P2X and/or G protein‐coupled P2Y receptor agonists ATP, ATPγS, α,β‐meATP, 2‐MeSATP, BzATP, ADP, CTP, and UTP on the intracellular Ca2+‐mobilization, actin polymerization, production of reactive oxygen metabolites, CD11b expression and chemotaxis of human eosinophils were measured and the biological activity was analyzed. Although all tested nucleotides were able to induce all these cell responses, the biological activity of the analyzed nucleotides were distinct. Agonists of the G protein‐coupled P2Y receptors such as 2‐MeSATP, UTP, and ADP have a higher biological activity for production of reactive oxygen metabolites, actin polymerization and chemotaxis in comparison to the ion channel‐gated P2X agonists αβ‐meATP, BzATP, and CTP. In contrast, P2Y and P2X agonist showed similar potencies in respect to intracellular calcium transient and CD11b up‐regulation. This conclusion was further supported by experiments with receptor iso‐type antagonist KN62, EGTA or with the Gi protein‐inactivating pertussis toxin. These findings indicate participation of different purinorecptors in the regulation of cell responses in eosinophils.


Strahlentherapie Und Onkologie | 2003

Concurrent Radiochemotherapy with Vinorelbine plus Cisplatin or Carboplatin in Patients with Locally Advanced Non-Small-Cell Lung Cancer (NSCLC) and an Increased Risk of Treatment Complications

Sabine Semrau; Anette Bier; Ulrike Thierbach; Christian Virchow; Peter Ketterer; Rainer Fietkau

Background:In elderly patients, patients with multiple morbidities, and patients with a reduced general condition, the standard treatment of inoperable non-small-cell lung cancer (NSCLC) consists of either chemotherapy or radiation therapy alone and is associated with an extremely poor prognosis. We therefore investigated the feasibility, toxicity, and efficacy of radiotherapy with concurrent chemotherapy using vinorelbine plus cisplatin or carboplatin in NSCLC patients at risk for treatment complications.Patients and Methods:A total of 33 patients (six women, 27 men, median age 65 years) with locally advanced, functionally inoperable pulmonary carcinomas, recurrent lung cancer or postoperative macroscopic residual tumors (R2) with an increased risk of treatment complications (WHO performance status 2/3; cardiac, renal or pulmonary failure; marked pretherapeutic weight loss; age between 71–75 years) received 12.5 mg of vinorelbine per m2 body surface area (BSA) on days 1, 8, 15, 29, 36 and 43 plus either cisplatin 20 mg/m2 BSA (ten patients) or carboplatin 70 mg/m2 BSA (23 patients) on days 1–5 and 29–33 together with conventionally fractionated radiotherapy. The tumor regions were irradiated with doses of up to 63 Gy (90% isodose), and potentially affected lymph nodes received doses of up to 45.0 or 50.4 Gy (90% isodose).Results:Briefly, 31 of 33 patients successfully completed radiation therapy and 26 received four cycles of vinorelbine plus at least two cycles of cisplatin or carboplatin. Hematotoxic side effects included grade III leukocytopenia (n = 8), grade III thrombocytopenia (n = 5), and grade IV thrombocytopenia (n = 2). Other side effects consisted of peripheral neuropathy grade III (n = 1) and esophagitis grade IV (n = 1). Severe pneumonitis did not occur. Six patients had pneumonia before radiochemotherapy. 21 patients (63%) exhibited a complete (n = 7) or partial response (n = 14) to chemoradiation. The twelve nonresponders had either stable (n = 9) or progressive disease (n = 3). The survival rates plus standard deviations were as follows: 1-year survival: 60 ± 8%, 2-year survival: 36 ± 9%, 3-year survival: 24 ± 9%, median survival time: 17 months (5;29 months; 95% confidence interval [CI]), median progression-free survival: 11 months (9;13 months; 95% CI). The median follow-up time was 14 months.Conclusion:Conventionally fractionated radiochemotherapy with vinorelbine plus a platinum derivative is feasible in patients with NSCLC and increased risk of treatment complications. Compared to patient populations described in the literature, the survival rates achieved by concurrent radiochemotherapy appear to be better than those achieved with radiotherapy alone.Hintergrund:Eine alleinige Bestrahlung oder Chemotherapie ist therapeutischer Standard bei multimorbiden, alten oder im Allgemeinzustand reduzierten Patienten mit inoperablen nichtkleinzelligen Bronchialkarzinomen (NSCLC). Die Prognose ist außerordentlich schlecht. Deshalb untersuchten wir die Durchführbarkeit, Toxizität und Wirksamkeit einer simultanen Radiochemotherapie mit Vinorelbin und Cisplatin oder Carboplatin bei Patienten mit NSCLC und erhöhtem Behandlungsrisiko.Patienten und Methodik:33 Patienten (sechs Frauen, 27 Männer, medianes Alter 65 Jahre) mit einem lokal fortgeschrittenen, funktionell inoperablen Bronchialkarzinom, Bronchialkarzinomrezidiv oder postoperativem makroskopischen Residualtumor (R2) mit erhöhten Behandlungsrisiken (WHO-Performance-Status 2/3 oder kardiale oder renale oder pulmonale Insuffizienz oder ausgeprägter prätherapeutischer Gewichtsverlust oder Alter zwischen 71 und 75 Jahren) erhielten 12,5 mg/m2 Körperoberfläche (KO) Vinorelbin an den Tagen 1, 8, 15, 29, 36 und 43 sowie Cisplatin 20 mg/m2 KO (zehn Patienten) oder Carboplatin 70 mg/m2 KO (23 Patienten) an den Tagen 1–5 und 29–33 zusammen mit einer konventionell fraktionierten Strahlentherapie der Tumorregionen bis 63 Gy (90%-Isodose) und potentiell befallener Lymphknoten bis 45,0 bzw. 50,4 Gy (90%-Isodose).Ergebnisse:Die Bestrahlung wurde bei 31 von 33 Patienten in voller Dosierung und die Chemotherapie bei 26 Patienten mit mindestens zwei Kursen Cisplatin oder Carboplatin und vier Kursen Vinorelbin durchgeführt. Hämatotoxische Nebenwirkungen schlossen Leukozytopenien Grad III (n = 8), Grad-III-Thrombozytopenien (n = 5) und Grad-IV-Thrombozytopenien (n = 2) ein. Sonstige Nebenwirkungen: periphere Neuropathie Grad III (n = 1) und Ösophagitis Grad IV (n = 1). Es war keine höhergradige Pneumonitis zu verzeichnen. Sechs Patienten hatten eine Pneumonie, die jeweils bereits vor Therapiebeginn bestand. 21 Patienten (63%) zeigten entweder eine komplette (n = 7) oder eine partielle Remission (n = 14) auf die Radiochemotherapie. Die zwölf Patienten ohne Therapieansprechen hatten entweder eine “stable disease“ (n = 9) oder waren progredient (n = 3). Die Überlebensraten einschließlich Standardabweichungen betrugen: 1-Jahres-Überlebensrate: 60 ± 8%, 2-Jahres-Überlebensrate: 36 ± 9%, 3-JahresÜberlebensrate: 24 ± 9%, mediane Überlebenszeit: 17 Monate (5;29 Monate; 95%-Konfidenzintervall [KI]), medianes progressionsfreies Überleben: 11 Monate (9;13 Monate; 95%-KI). Die mediane Nachbeobachtungszeit lag bei 14 Monaten.Schlussfolgerung:Eine konventionell fraktionierte Radiochemotherapie mit Vinorelbin und einem Platinderivat ist bei Patienten mit NSCLC und erhöhten Therapierisiken durchführbar. Verglichen mit aus der Literatur bekannten Ergebnissen einer alleinigen Bestrahlung scheinen durch eine simultane Radiochemotherapie bessere Überlebensraten möglich.


European Respiratory Journal | 2016

NTPDase1/CD39 and aberrant purinergic signalling in the pathogenesis of COPD.

Zsofia Lazar; Nina Müllner; Monica Lucattelli; Cemil Korcan Ayata; Sanja Cicko; Gennady G. Yegutkin; Giovanna De Cunto; Tobias Müller; Anja Meyer; Madelon Hossfeld; Stephan Sorichter; Ildiko Horvath; Christian Virchow; Simon C. Robson; Giuseppe Lungarella; Marco Idzko

Purinergic receptor activation via extracellular ATP is involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). Nucleoside triphosphate diphosphohydrolase-1/CD39 hydrolyses extracellular ATP and modulates P2 receptor signalling. We aimed to investigate the expression and function of CD39 in the pathogenesis of cigarette smoke-induced lung inflammation in patients and preclinical mouse models. CD39 expression and soluble ATPase activity were quantified in sputum and bronchoalveolar lavage fluid (BALF) cells in nonsmokers, smokers and COPD patients or mice with cigarette smoke-induced lung inflammation. In mice, pulmonary ATP and cytokine concentrations, inflammation and emphysema were analysed in the presence or absence of CD39. Following acute cigarette smoke exposure CD39 was upregulated in BALF cells in smokers with further increases in COPD patients. Acute cigarette smoke exposure induced CD39 upregulation in murine lungs and BALF cells, and ATP degradation was accelerated in airway fluids. CD39 inhibition and deficiency led to augmented lung inflammation; treatment with ATPase during cigarette smoke exposure prevented emphysema. Pulmonary CD39 expression and activity are increased in COPD. CD39 deficiency leads to enhanced emphysema in mice, while external administration of a functional CD39 analogue partially rescues the phenotype. The compensatory upregulation of pulmonary CD39 might serve as a protective mechanism in cigarette smoke-induced lung damage. The upregulation of pulmonary ATPase is a protective mechanism in cigarette smoke-induced lung inflammation http://ow.ly/S5YcC


ISMDA '00 Proceedings of the First International Symposium on Medical Data Analysis | 2000

Detection and Classification of Sleep-Disordered Breathing Using Acoustic Respiratory Input Impedance and Nasal Pressure

H. Steltner; Richard Staats; Michael Vogel; Christian Virchow; Heinrich Matthys; Josef Guttmann; Jens Timmer

We are developing an algorithm for off-line detection and classification of sleep-disordered breathing based on time series analysis of nasal mask pressure and acoustic respiratory input impedance measured by forced oscillation technique at a frequency of 20 Hz throughout the night. A first version of the algorithm was applied to a data set consisting of full-night measurements on 5 subjects. The data set had a total duration of 34 hours and contained 577 respiratory events (hypopneas, obstructive and central apneas) recognized by the staff physicians of an accredited sleep laboratory. The algorithm detected 455 (79 %) of these events and 138 events that had not been marked by the physicians. 75 % of the congruently detected events were also concordantly classified. After further optimization and evaluation, this approach might be useful when implemented into a device designed to screening or treatment control of sleep-related breathing disorders at home.


Biomedizinische Technik | 2000

KLASSIFIZIERUNG VON SCHLAFAPNOEN AUF DER BASIS VON NASALEM DRUCK UND ATEMWEGSIMPEDANZ

H. Steltner; Richard Staats; Michael Vogel; Jens Timmer; Christian Virchow; Heinrich Matthys; Josef Guttmann

Schlaf bezogene Atemregulationsstörungen stellen ein Krankheitsbild mit bedeutender epidemiologischer Tragweite dar. Etwa 4 % der männlichen und 2 % der weiblichen Bevölkerung im Alter von 30 bis 60 Jahren leiden unter einem klinisch relevanten Schlafapnoesyndrom [1]. Die Diagnose schlafbezogener Atmungsstörungen erfolgt üblicherweise im Rahmen eines mehrtägigen Aufenthaltes im Schlaflabor, der mehrere Polysomnographien einschließt. Die Polysomnographie stellt zur Zeit den kostenund zeitintensiven Goldstandard der Schlafdiagnostik dar und beinhaltet die Aufzeichnung einer Vielzahl physiologischer Signale, die zur Beurteilung des Schlafes und der nächtlichen Atmung herangezogen werden. Zwei Signale, die momentan nicht zum Standardrepertoire der PSG gehören, sind die resistooszillometrisch gemessene akustische Atemwegsimpedanz Z und der nasale Druck p, die simultan über eine nasale Maske zugänglich sind. Z enthält Informationen über Querschnitt und mechanische Eigenschaften der oberen Atemwege [2, 3], p ist ein sensitiver Indikator für gestörte Atmung im Schlaf [4]. Ein wesentlicher Aspekt der Differentialdiagnose schlafbezogener Atmungsstörungen im Hinblick auf die Wahl einer adäquaten Therapie ist die Erkennung und Unterscheidung von verschiedenen nächtlichen respiratorischen Ereignissen von mindestens 10 Sekunden Dauer: Hypopnoen sind Phasen mit stark reduziertem Atemfluss. Obstruktive Apnoen sind Atemstillstände, bei denen die oberen Atemwege verschlossen sind, der Patient aber versucht, weiter zu atmen, so dass gegenläufige Bewegungen von Brustkorb und Zwerchfell beobachtet werden können. Bei zentralen Apnoen setzen neben dem Atemfluss auch diese Bewegungen aus. Gemischte Apnoen sind gekennzeichnet durch einen zentralen Anteil zu Beginn und eine obstruktive Phase gegen Ende des Atemstillstandes. Wir entwickeln ein Verfahren zur automatischen Detektion und Klassifizierung respiratorischer Ereignisse, das auf der Analyse des Betrags der Atemwegsimpedanz \Z\ und des nasalen Drucks p basiert. Abbildung 1: Kardiorespiratorische Signale bei Hypopnoe und obstruktiver Apnoe; Sao2 in %, p in mbar, die übrigen Signale in arbiträren Einheiten


Chest | 2002

Occlusal and Skeletal Effects of an Oral Appliance in the Treatment of Obstructive Sleep Apnea

Edmund Rose; Richard Staats; Christian Virchow; Irmtrud E. Jonas


European Journal of Orthodontics | 2002

A comparative study of two mandibular advancement appliances for the treatment of obstructive sleep apnoea.

Edmund Rose; Richard Staats; Christian Virchow; Irmtrud E. Jonas

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Marco Idzko

University of Freiburg

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Rainer Fietkau

University of Erlangen-Nuremberg

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Sabine Semrau

University of Erlangen-Nuremberg

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