Plasma concentration and acute clinical effects of docarpamine,orally active dopamine prodrug,in infants

Currently, there are no data available on the optimal doses and efficacy of docarpamine in infants. In the present study, three doses of docarpamine, 15.0–20.4 (19.0 ± 1.9; mean ± SD) mg/kg per dose every 8 h to 10 infants suffering heart failure. Age and bodyweight were from 1 to 4 (1.4 ± 1) months and 2960–5160 (3350 ± 872) g, respectively. In all infants, plasma concentrations of free dopamine were measured 1, 2 and 3 h after the first administration. Heart rate and systolic blood pressure were examined before and at the same time as the first administration. In seven infants, the 24 h urinary output and urinary excretion of electrolytes and creatinine before and during docarpamine were measured. Peak plasma concentration of free dopamine (ng/mL) was achieved after 1 or 2 h of administration, 0–163.1 (37.9 ± 47.2) and 0–105.0 (37.8 ± 39.3), respectively. The concentration had decreased rapidly by 3 h to 0–34.2 (12.4 ± 11.0). Both heart rate (b.p.m.) and blood pressure (mmHg) tended to increase from 120–154 (140 ± 15) and 56–90 (76 ± 11) to a peak of 124–162 (148 ± 14) and 70–92 (79 ± 8), respectively (P = 0.197, P = 0.289). There were no significant changes in urinary output or excreta. Oral docarpamine of 15–20 mg/kg per dose can achieve plasma free concentrations of dopamine that increase heart rate and systolic blood pressure.     

Shrinkage of tissue conditioners with time — effect of the particle size in powder and the EtOH content in liquid

The dimensional change of tissue conditioners with time was measured until 4 weeks after mixing. Shrinkage of the materials was evaluated in relation to particle size in powder and the EtOH content in liquid. The dissolution of EtOH and plasticizer were also measured to investigate the relation to dimensional change. Shrinkage with time was recorded. The smaller the particle size in powder and the more EtOH in liquid, the greater the shrinkage rate. The smaller the particle size in the powder and the more EtOH contained in the liquid, the greater the dissolution of EtOH. The dissolution of BPBG was below 1/100 comparing that of EtOH and no difference was recognized by particle size and EtOH content. On the basis of these results it is suggested that the dissolution of EtOH is related to shrinkage of tissue conditioners with time and that the component particle size in the powder and EtOH content in the liquid have a significant influence on dissolution of EtOH associated with shrinkage.     

Left Atrial Catheter Ablation Promotes Vasoconstriction of the Right Coronary Artery

Background: Multiple cardiac ganglia are present in the left atrial (LA) region, and marked changes in autonomic nervous activity can occur after left atrial catheter ablation (CA) for atrial fibrillation (AF). Vasospastic angina involving the inferior wall of the left ventricle has been reported as a complication shortly after LACA.
Methods: We studied 20 patients with drug-refractory AF who underwent LACA, performed to encircle the left- and right-sided pulmonary veins, 1 to 2 cm from their ostia under fluoroscopic guidance. Quantitative coronary angiography was performed before and after LACA, and we analyzed the minimal lesion diameter (MLD) of the proximal segment of the coronary arteries, and the basal tone, the baseline percent constriction versus maximal dilation after nitroglycerin administration.
Results: No significant difference was observed in MLD or basal tone of the left coronary arteries after LACA. However, in the right coronary artery (RCA), the basal MLD was smaller (P < 0.01) and the basal tone was greater (P< 0.05) after than before LACA. No correlation was found between the baseline MLD or tone of the RCA and total amount of radiofrequency energy delivered or procedure duration. In 75% of RCA, the baseline MLD was smaller after than before LACA, which was significantly higher (P < 0.01) than observed in the left coronary arteries (38%).
Conclusion: Vasoconstriction was promoted in the RCA shortly after LACA, which may explain the variant angina reported after LACA.     

Simple Electrocardiographic Criteria for Identifying the Site of Origin of Focal Right Atrial Tachycardia

To construct an algorithm for identifying the precise site of origin of focal right atrial tachycardia (RAT), we analyzed the P wave configuration in 32 patients with RAT who underwent successful radiofrequency catheter ablation. The RA was divided into three areas in the left anterior oblique view: superolateral, inferolateral, and inferomedial. There were 17 RATs arising from the crista terminalis (CT-AT), 12 from the tricuspid annulus (TA-AT), and 3 from the septum away from the TA (Sep-AT). A negative P wave in lead aVR identified CT-AT with a sensitivity (sens) of 100% and a specificity (spec) of 93%. In CT-AT's, positive P waves in the inferior leads differentiated superolateral AT from inferolateral A T with a sens of 86% and a spec of 100%. In any type of AT with inferomedial or inferolateral foci, the P wave deflections in at least one of the inferior leads was negative, and negative P waves in leads V5 and V6 identified inferomedial AT with a sens of 92% and a spec of 100%. In ATs near the apex of Koch's triangle, the P wave duration in the inferior leads was shorter than during sin us rhythm. Conclusions: (1) the P wave configuration in lead aVR can easily differentiate CT-AT from TA-AT and Sep-AT; (2) the P wave configuration in the inferior leads helps to determine a superior versus inferior origin in any type of AT; (3) in inferior AT, the P wave polarity in leads V₅ and V₆ is useful in determining a lateral versus medial origin; (4) this algorithm can predict accurately the origin of AT.     

Catheter Ablation for Ventricular Tachycardia from a Diverticulum at the Right Ventricular Outflow Tract

A case is presented of a 73-year-old man with drug resistant ventricular tachycardia that originated from the right ventricular outflow tract. A right ventriculogram showed a diverticulum in the interventricular septum at the right ventricular outflow tract. Low energy radiofrequency catheter ablation within the diverticulum was performed successfully and safely.     

Viscoelastic properties of tissue conditioners — stress relaxation test using Maxwell model analogy

In order to measure the viscoelastic properties of tissue conditioners, a series of stress relaxation tests was carried out using poly ethyl methacrylate polymer powders and liquids composed of butyl phthalyl butyl glycolate/ethyl alcohol mixtures, respectively. The analysis method using the Maxwell model analogy is discussed. The results may be summarized as follows. (i) In this study it was feasible to make the stress relaxation curves for 30 min analogous to the Maxwell model, using a model with a maximum of 5 elements. (ii) The elastic modulus Ei, the coefficient of viscosity eta i, and relaxation time tau i, for each element, and the instantaneous modulus E0, tended to increase with time. These values in the element of the longest relaxation time were most marked in the increase among those in all the elements. Furthermore, in every element the rate of increase of eta i was greater than that of Ei. The method described is considered to be one of the most useful techniques available for the study of the viscoelastic properties of tissue conditioners.     

Differential Effects of Dopamine Antagonists on Evoked Dopamine Release from Slices of Striatum and Nucleus Accumbens in Rats

The effects of dopamine-receptor antagonists on electrically-evoked dopamine release were compared in the nucleus accumbens and striatal slices of rats. (-)-Sulpiride induced a concentration-dependent increase in the evoked dopamine release from both regions, the increase in the nucleus accumbens being significantly greater than that in the striatum. Clozapine also increased evoked dopamine release from the nucleus accumbens, but not from the striatum. The haloperidol-induced increase in evoked dopamine release from the nucleus accumbens was less than that from the striatum. These findings indicate that, in terms of dopamine transmission, (-)-sulpiride and clozapine, but not haloperidol, predominantly affect the nucleus accumbens rather than the striatum. We have previously reported that the contribution of D₃ receptors to the regulation of dopamine release from dopamine nerve terminals is much greater in the nucleus accumbens than that in the striatum. (-)-Sulpiride and clozapine have relatively higher affinity for D₃ receptors than does haloperidol. The regional differences in responsiveness of dopamine release to dopamine antagonists could be due to the different affinities to D₂ or D₃ receptors of the dopamine antagonists.     

Viscoelastic properties of tissue conditioners — influence of ethyl alcohol content and type of plasticizer

The effect of both the ethyl alcohol content of liquids and the type of plasticizer on the viscoelastic properties after gelation of tissue conditioners was studied by means of a stress relaxation test. The results are summarized as follows. The liquids containing the larger percentages of ethyl alcohol produced the larger flow after gelation. Furthermore, the ethyl alcohol content had a significant influence on changes in viscoelastic properties with the passage of time. Flow properties were found to reduce rapidly with time of storage with an increase in the ethyl alcohol content. The use of benzyl benzoate produced the larger flow after gelation than dibutyl phthalate, which in turn produced the larger flow than butyl phthalyl butyl glycolate. The type of plasticizer, however, was found to have no influence on changes in viscoelastic properties with the passage of time.     

Multiple Endocrine Neoplasia Type 2b (I) Report of a Case

This is a case report of a 14-year-old girl with multiple endocrineneoplasia (MEN) type 2b. The patient had mucosal neuromas, medullarycarcinoma of the thyroid, bumpy lips, hypertrophied cornealnerves, absent flare response following intradermal histamineinjection, high arched palate, oligodontia, pes cavus and polypoidlesions in the colon. Urinary catecholamines were normal andthe patient's blood pressure did not rise abnormally after glucagonor histamine infusions. The left adrenal gland was not visualizedon examination by adrenal scintiscanning, but by computed tomographyit was enlarged. Nerve growth factor (NGF) was normal in theserum. Extensive studies failed to identify other family memberswith MEN. This patient seems to be a sporadic case.