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Biomedical subjects

A Cordes

Publications and source records attributed to A Cordes.

10 recordsLinked to original sources

[Phenprocoumon-induced liver failure].

HISTORY: A 61-year-old woman was referred because of painless jaundice, laboratory tests having indicated hepatitis with impaired liver functions. For the past two years she had been taking phenprocoumon because she had atrial fibrillation. INVESTIGATIONS: Serological tests largely excluded infectious, autoimmune or metabolic etiology, so that the diagnosis of drug-induced hepatic disease was made. Liver biopsy showed necrotic liver cells and mild inflammatory reaction. TREATMENT AND COURSE: A perforating duodenal ulcer required urgent surgical intervention, after which liver functions further deteriorated. The patient having refused liver transplantation she was treated symptomatically (oral vitamin K. lactulose, diuretics), phenprocoumon was discontinued and her condition slowly improved. She was discharged after two months. At subsequent examination she was symptom-free, the INR was 1.41, transaminases were normal and ultrasound merely showed a slightly inhomogeneous internal structure. CONCLUSION: Phenprocoumon can cause liver damage even when the drug has been taken for prolonged periods without any problems. A careful history about previously administered drugs should be taken in any case of hepatitis of uncertain etiology.

Anticoagulants↗

[Pantoprazole-induced hepatitis].

HISTORY: A 46-year-old woman presented for an emergency admission because of colic-like upper abdominal pain and markedly impaired general condition. Eight days before admission she had started and continued to take pantoprazole because of symptoms of gastroesophageal reflux. INVESTIGATIONS: Clinical examination and laboratory tests indicated abnormal liver functions suggesting hepatitis. Serology largely excluded an infectious, autoimmunological or metabolic cause. Duplex sonography gave no evidence of bile obstruction or Budd-Chiari syndrome. DIAGNOSIS AND COURSE: The patient's condition and laboratory tests after the drug had been discontinued gradually improved on symptomatic treatment, indicating pantoprazole-induced hepatitis. CONCLUSION: Intake of proton pump inhibitors is a rare cause but should be considered in the differential diagnosis of hepatitis of uncertain etiology.

2-Pyridinylmethylsulfinylbenzimidazoles↗

Pentobarbital and brilliant green modulate the current response of recombinant rat kainate-type GluR6 receptor channels differentially.

Kainate-type receptor channels (GluR5-7, KA1,2) belong to the family of ionotropic glutamate receptor channels. In the present study we tested the interaction of two different drugs with GluR6 channels using outside-out patches from HEK cells transiently transfected with cDNA of GluR6 channels. Glutamate and the respective drugs were delivered by a system for ultrafast solution exchange. Application of a saturating concentration of 3 mM glutamate resulted in fast current transients with desensitization time constants between 3 and 10 ms. Addition of pentobarbital (>or=1 mM) to the 3 mM glutamate containing test-solution resulted in a significant decrease of the time constant of current decay without affecting the peak current amplitude. Brilliant green (>or=1 mM) had the opposite effect and led to an increase of the time constant of current decay after application of 3 mM glutamate. The pharmacological effects of both drugs were completely reversible. Additionally, a significant increase of the peak current amplitude and the time constant of deactivation in presence of brilliant green was observed. Summarizing our results, we could identify a further substance, brilliant green, interacting with GluR6 kainate-type receptor channels.

Cells, Cultured↗

Coexistence of purino- and pyrimidinoceptors on activated rat microglial cells.

1. Nucleotide-induced currents in untreated (proliferating) and lipopolysaccharide (LPS; 100 ng ml(-1)) treated (non-proliferating) rat microglial cells were recorded by the whole-cell patch-clamp technique. Most experiments were carried out on non-proliferating microglial cells. ATP (100 nM-1 mM), ADP (10 nM-10 mM) and UTP (1 microM-100 mM), but not uridine (100 microM-10 mM) produced a slow outward current at a holding potential of 0 mV. The effect of UTP (1 mM) did not depend on the presence of extracellular Mg2+ (1 mM). The outward current response to UTP (1 mM) was similar in non-proliferating and proliferating microglia. 2. In non-proliferating microglial cells, the ATP (10 microM)-induced outward current was antagonized by suramin (300 microM) or reactive blue 2 (50 microM), whereas 8-(p-sulphophenyl)-theophylline (8-SPT; 100 microM) was inactive. By contrast, the current induced by UTP (1 mM) was increased by suramin (300 microM) and was not altered by reactive blue 2 (50 microM) or 8-SPT (100 microM). 3. The current response to UTP (1 mM) disappeared when K+ was replaced in the pipette solution by an equimolar concentration of Cs+ (150 mM). However, the effect of UTP (1 mM) did not change when most Cl- was replaced with an equimolar concentration of gluconate (145 mM). The application of 4-aminopyridine (1 mM) or Cs+ (1 mM) to the bath solution failed to alter the UTP (1 mM)-induced current. UTP (1 mM) had almost no effect in a nominally Ca2+-free bath medium, or in the presence of charybdotoxin (0.1 microM); the inclusion of U-73122 (5 microM) or heparin (5 mg ml(-1)) into the pipette solution also blocked the responses to UTP (1 mM). By contrast, the effect of ATP (10 microM) persisted under these conditions. 4. I-V relations were determined by delivering fast voltage ramps before and during the application of UTP (1 mM). In the presence of extracellular Cs+ (1 mM) and 4-aminopyridine (1 mM) the UTP-evoked current crossed the zero current level near -75 mV. Omission of Ca2+ from the Cs+ (1 mM)- and 4-aminopyridine (1 mM)-containing bath medium or replacement of K+ by Cs+ (150 mM) in the pipette solution abolished the UTP current. 5. Replacement of GTP (200 microM) by GDP-beta-S (200 microM) in the pipette solution abolished the current evoked by UTP (1 mM). 6. When the pipette solution contained Cs+ (150 mM) instead of K+ and in addition inositol 1,4,5,-trisphosphate (InsP3; 10 microM), an inward current absolutely dependent on extracellular Ca2+ was activated after the establishment of whole-cell recording conditions. This current had a typical delay, a rather slow time course and did not reverse its amplitude up to 100 mV, as measured by fast voltage ramps. 7. A rise of the internal free Ca2+ concentration from 0.01 to 0.5 microM on excised inside-out membrane patches produced single channel activity with a reversal potential of 0 mV in a symmetrical K+ solution. The reversal potential was shifted to negative values, when the extracellular K+ concentration was decreased from 144 to 32 mM. By contrast, a decrease of the extracellular Cl- concentration from 164 to 38 mM did not change the reversal potential. 8. Purine and pyrimidine nucleotides act at separate receptors in rat microglial cells. Pyrimidinoceptors activate via a G protein the enzyme phospholipase C with the subsequent release of InsP3. The depletion of the intracellular Ca2+ pool appears to initiate a capacitative entry of Ca+ from the extracellular space. This Ca2+ then activates a Ca2+-dependent K+ current.

Adenosine Triphosphate↗

Effects of different inotropes with antioxidant properties on acute regional myocardial ischemia in isolated rabbit hearts.

1. The antiischemic properties of the flavonoids acetylvitexin-rhamnoside (AVR) and luteolin-7-glucoside-(LUT), combining phosphodiesterase (PDE)-inhibitory and antioxidant properties, were studied in comparison to amrinone (AMR) or superoxide dismutase (SOD). The effects of the new dihydropyridine-type calcium-agonist Bay T 5006 were studied in comparison to Bay K 8644. 2. In isolated Langendorff-rabbit hearts perfused at constant pressure, acute regional ischemia (MI) was induced by coronary artery occlusion (CAO) and quantitated from epicardial NADH-fluorescence photography. Drugs were applied either before or after CAO (pre-treatment or treatment) to permit distinguishing the influence of functional and direct cytoprotective actions in the poorly collateralized rabbit hearts. 3. SOD did not affect left ventricular pressure (LVP) or coronary flow (CF) and reduced MI only if applied before CAO. LVP and CF were enhanced by LUT or AMR but not by AVR. MI was reduced to a similar extent in hearts treated with either drug. Cardioprotection by LUT was not improved by starting drug application before CAO. 4. Bay K 8644 reduced LVP and particularly CF, whereas Bay T 5006 did not affect functional parameters. MI was enlarged by Bay K 8644 and remained unaffected by treatment or pretreatment with Bay T 5006. 5. AMR, LUT and AVR possess antiischemic properties related to an improvement of myocardial perfusion. Although oxygen free radicals contribute to ischemic tissue injury, as shown by the cardioprotective effectiveness of SOD, antioxidant properties of the flavonoids LUT and AVR do not seem to be relevant for the antiischemic effects. Our findings also give no evidence for antioxidant properties of dihydropyridines relevant for cardioprotection.

Animals↗

Functional and antiischemic effects of luteolin-7-glucoside in isolated rabbit hearts.

1. The functional effects of the flavonoid luteolin-7-glucoside (LUT) were investigated in Langendorff-rabbit hearts perfused at constant pressure. Repetitive myocardial ischemia was induced by coronary artery ligature and quantified from NADH-fluorescence photography. 2. LUT significantly enhanced left ventricular pressure and the global and relative coronary flow (= global coronary flow/pressure-rate product). 3. LUT significantly diminished epicardial NADH-fluorescence area and intensity. 4. LUT is an inodilator possessing cardioprotective properties. These might be related to an improvement of myocardial perfusion and/or to free radical scavenging properties.

Animals↗