Variability in response to clopidogrel: where is the threshold for 'low response'?: reply

We appreciate to read Dr Komócsís comments toour article entitled ‘Low response to clopidogrel is associatedwith cardiovascular outcome after coronary stent implantation’. He critically remarked the mortality rate in our study. Indeed,we found an all-cause mortality of 5.2% within 3 months (cardiovascularmortality: 3.9%). However, it is worthy to note that we investigatedan unselected patient collective with moderate- to     

Akuter thrombembolischer ST-Hebungs-Infarkt bei einem Patienten mit essenzieller Thrombozytose

A 48-year-old man presented with acute chest pain and a greatly increased platelet count. Emergency coronary angiographc revealed thrombotic occlusion of the right coronary artery. Coronary angioplasty and stenting were successfully combined with intracoronary abciximab administration. Due to inadequate postinterventional platelet inhibition an intensified dual antiplatelet therapy with acetylsalicylic acid (ASS) and clopidogrel was applied to prevent stent thrombosis. Due to the thrombo-embolic complication and a platelet count over 1 million/µl a cytoreductive treatment with hydroxyurea was initiated.     

Two-tone suppression by a saturating feedback model of the cochlear partition.

A model of a small strip of cochlear partition was computer simulated. The model is composed of two elements, approximations to the transfer functions of an inner hair cell (IHC) and an outer hair cell (OHC), respectively. The IHC element was insensitive to DC stimulation. Input was one or two sinusoids. One sinusoid, at the characteristic frequency (CF), was multiplied by the gain of the 'cochlear amplifier'. A second sinusoid, representing a tone with much lower frequency, was not affected by the amplifier gain. This gain was determined by the OHC transfer function. In one form of the model ('fixed-gain'), this gain was set at a fixed number determined from the furthest point reached on the OHC transfer function. This form of the model produced very realistic single-tone responses as well as showing 'two-tone suppression': that is, the IHC DC response produced by CF stimulation was reduced when the lower-frequency sinusoid, at suitable intensities, was added to the stimulus. When a DC component was added to the two-tone stimulus, the magnitude of this two-tone suppression was enhanced. In the second form of the model ('variable-gain'), the cochlear-amplifier gain varied throughout the stimulus cycle. Its value was re-calculated at each instant, determined by the point on the OHC transfer function current at that particular instant. This form of the model showed two-tone suppression only when a DC component was added to the two-tone stimulus.     

Two-tone suppression, excitation and the after effect in rate responses in auditory nerve fibres in the cat.

Responses were recorded from single, auditory nerve fibres in the anaesthetized cat. Acoustic stimuli consisted of two tones, one of which was at characteristic frequency (CF), the other (the suppressor) was at considerably lower frequency. Tones were presented in simultaneous and sequential configurations. For simultaneous presentations, well-known response properties were observed. The rising limb of the two-tone rate-intensity function closely matched that of the appropriately adapted response to the suppressor tone presented alone. Also, whether strongly suppressed relative to CF-driven rate, or equal to CF-driven rate, rate responses to the two-tone stimuli persisted unchanged when the CF tone was terminated and the suppressor tone continued alone. These results support the hypothesis that the suppressor tone has dual influences, suppressive and excitatory, that are distinct and additive. Peristimulus response histograms confirm in the cat that depression and slow recovery of sensitivity to CF may follow termination of the suppressor tone, as reported for the guinea pig [Hill, K.G. and Palmer, A.R. (1991) Hear. Res. 55, 167-176]. This delay in recovery of normal sensitivity to CF appeared to be directly related to the amount of excitation of the fibre that is attributable to the suppressor tone. A similar, delayed re-establishment of sensitivity also occurred in the response to a tone at CF, presented immediately following excitation by a suppressor tone. However, no delay occurred in the onset of response to the suppressor when preceded by the CF tone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Electrocardiographic criteria of left atrial enlargement: do they correlate with atrial size?

In the past, M-mode echocardiography, the "gold standard" for determining left atrial dimension (LAD), has been used to examine the validity of the New York Heart Association criteria for left atrial enlargement (LAE). When the authors used two-dimensional echocardiography to determine LAD in 91 patients, they found no significant correlation between any of these criteria, either alone or together, and actual LAE. They propose that if the diagnosis of LAE is made using these criteria alone, that it be qualified at all times with the word "possible."