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E Jansen

Publications and source records attributed to E Jansen.

74 records · Page 5Linked to original sources
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Hyperpolarization-activated inward current in ventricular myocytes from normal and failing human hearts.

BACKGROUND: The hyperpolarization-activated inward current (I[f]) was found to be overexpressed in hypertrophied rat ventricular myocytes, indicating that I(f) might favor arrhythmias in hypertrophied or failing ventricular myocardium. In the present study, we evaluated whether I(f) is expressed in human ventricular myocardium, if it may be increased in human heart failure, and if its autonomic modulation may be altered. METHODS AND RESULTS: The whole-cell patch-clamp technique was used to record I(f) in isolated ventricular myocytes from 34 failing (dilated [DCM] or ischemic [ICM] cardiomyopathy) and 13 donor hearts (NF). I(f) was observed in all myocytes showing typical current properties, ie, time and voltage dependence, block by [Cs+]o, permeability for K+ and Na+, and current increase with raising [K+]o. There was a trend toward larger current densities in myopathic (at -130 mV in [K+]o 25 mmol/L; DCM: -1.37 +/- 0.12 pA/pF, n = 50; ICM: -1.39 +/- 0.24 pA/pF, n = 30) than in nonfailing cells (-1.18 +/- 0.21 pA/pF, n = 24), although this difference did not reach statistical significance (P=.23). Boltzmann distributions yielded an activation threshold of -80 mV and half-maximal activation at -110.96 +/- 0.06 mV in myopathic and normal myocytes. Isoproterenol (10(-5) mol/L) shifted the current activation by 10 mV (31 myopathic, 5 NF). Carbachol and adenosine had no direct effect on I(f) (6 and 12 myopathic, 3 and 3 NF, respectively) but reversibly antagonized beta-adrenergic stimulation (5 and 7 myopathic, 2 and 2 NF, respectively). Autonomic modulation was similar in failing and nonfailing cells. CONCLUSIONS: In end-stage heart failure, no significant change of I(f) could be found, although there was a trend toward increased I(f). Together with an elevated plasma norepinephrine concentration and a previously reported reduction in I(K1) in human heart failure, I(f) might favor diastolic depolarization in individual myopathic cells.

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Screening for tamoxifen ocular toxicity: a prospective study.

Specific ocular complications, namely retinopathy, keratopathy and optic neuritis, have been described in women being treated with tamoxifen for metastatic breast cancer or taking this drug as an adjuvant postoperative therapy. We examined 61 patients who had been using tamoxifen for at least one year, in order to detect the incidence of ocular complications. Two patients had retinopathy after having taken high cumulative doses of tamoxifen. Another had corneal deposits and a fourth had optic neuritis. It thus appears that systematic screening of all symptom-free patients using this drug for metastatic breast cancer is superfluous. However, an ophthalmological assessment every two years or earlier in case of visual complaints for patients taking tamoxifen as an adjuvant therapy remains useful, because the oncological therapy can be adjusted if serious ocular complications arise.

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