Nanomolar concentrations of tri-n-butyltin facilitate gamma-aminobutyric acidergic synaptic transmission in rat hypothalamic neurons

Tri-n-butyltin (TBT), an environmental pollutant, is accumulated in edible mollusks and fishes. It has also become a health concern in today's society. In the present study, to elucidate the possible neurotoxic action of TBT, the effect on spontaneous gamma-aminobutyric acid (GABA) release from GABAergic nerve terminals projecting to rat ventromedial hypothalamic neurons was examined using "synaptic bouton" preparation with a nystatin perforated patch recording mode under voltage-clamp conditions. The threshold concentration of TBT to affect the synaptic transmission was 10 to 30 nM. TBT at 30 nM or higher concentrations increased the frequency of GABAergic miniature inhibitory postsynaptic currents in a dose-dependent manner, whereas the current amplitude and current kinetics were not affected. The removal of either external Ca2+ or application of Cd2+ attenuated the TBT-induced facilitation of neurotransmission. TBT at 1 microM induced an inward current in more than one-half of the cells. This current persisted even after TBT was washed out. The present results indicate that TBT at environmentally relevant concentrations (30-100 nM) facilitates the GABAergic neurotransmission in the mammalian brain and the external Ca2+ is needed in this facilitation. Because the concentration of TBT accumulated in some mollusks and fishes has been reported to reach levels of 100 nM or more, such accumulation of TBT in some mollusks and fishes is thus suggested to be hazardous to the health of humans.     

A new method for measurement of right ventricular residual ratio using 121I-MAA

A new technique of precordial counting with 131I-MAA for measurement of right ventricular residual ratio (RVRR) was described. 131I-MAA was rapidly injected injected into the right ventricle at the time of right heart catheterization. The fraction of isotope discharged from this chamber per beat was determined with a crystal detector with tapered collimator which was pointed to the center of right ventricle. The radioisotope dilution curve was corrected by using the lung built up curve recorded by the other detector pointed to the lung field. Then, the right ventricular end-systolic volume (ESV) and the right ventricular end-diastolic volume (EDV) were calculated from the RVRR and stroke volume. In 6 patients with normal hemodynamics, the RVRR averaged 57.8 plus or minus 4.9%, the ESV 52.2 plus or minus 13.6 ml/M(2) and the EDV 89.4 plus or minus 15.1 ml/M(2). In 16 patients with heart diseases, the RVRR averaged 60.6 plus or minus 7.1%, the ESV 80.6 plus or minus 34.0 ml/M(2) and the EDV 127.2 plus or minus 43.6 ml/M(2). In 11 patients with chronic pulmonary diseases, the RVRR averaged 70.7 plus or minus 9.9%, the ESV 94.7 plus or minus 42.4 ml/M(2) and the EDV 133.0 plus or minus 46.5 ml/M(2). The RVRR in the last group increased significantly.     

Differences of side branch jailing between left main–left anterior descending artery stenting and left main–left circumflex artery stenting with Nobori biolimus-eluting stent

The aim of this study is to indicate differences of side branch jailing between the left main (LM)–left anterior descending artery (LAD) stenting and the LM–left circumflex artery (LCx) stenting. Thirty-one patients who underwent single-stenting using a two-link ten-crowns biolimus-eluting stent (Japanese design of BES, J-BES) and subsequent kissing balloon dilation (KBD) on an LM bifurcation with optical coherence tomography (OCT) were divided into two groups according to the stented vessel. Bifurcation angles were measured by three-dimensional (3D) quantitative coronary analysis. The jailing pattern on a side branch ostium was evaluated by stent-enhanced 3D-OCT. Incomplete stent apposition (ISA) after KBD was compared between the stented vessels. The to-be-stented angle of the LM–LCx stenting (n = 11) was significantly steeper than that of the LM–LAD stenting (n = 20) (132.6° ± 16.9° vs. 150.7° ± 10.6°, p < 0.01). The incidence of the free carina type, which has no stent links bridging from a carina, in the LM–LCx stenting was significantly higher than that in the LM–LAD stenting (90.9 vs. 45.0 %, p = 0.02). The percentage of ISA at the bifurcation segment in the LM–LCx stenting was significantly smaller than that in the LM–LAD stenting (4.4 ± 8.2 vs. 12.7 ± 9.2 %, p = 0.0003). This study showed, by higher incidence of the favorable configuration, that the LM–LCx stenting achieved a smaller percentage of ISA than the LM–LAD stenting. These insights may help guide LM bifurcation stenting with J-BES.     

A case of primary pulmonary hypertension treated with prazosin and isosorbide dinitrate

Successful vasodilator therapy of a 27-year-old woman with primary pulmonary hypertension is described. Prazosin 2 mg, orally in combination with isosorbide dinitrate 10 mg, sublingually caused a marked fall in pulmonary vascular resistance. Pulmonary hemodynamics reevaluated after 3 months of combination therapy with prazosin 1 mg qid and isosorbide dinitrate 5 mg qid showed sustained improvement. Therefore, in selected patients with primary pulmonary hypertension, this combination therapy can be used.     

Intravenous recombinant tissue-type plasminogen activator in patients with acute myocardial infarction--a report from the multicenter thrombolysis trial

The efficacy and safety of intravenous infusion of human tissue-type plasminogen activator (rt-PA), developed in Japan (TD-2061), were investigated in 205 patients (154 men and 51 women) with evolving myocardial infarction (EMI). TD-2061 was given at a rate of 3.2 to 50 mg over 1 h after angiographic documentation of complete or subtotal (99%) occlusion. Nineteen patients were excluded as they did not meet the inclusion criteria. A total of 186 patients were divided into 6 groups according to the total dose given: Group I, 3.2 mg, 10 patients (pts); Group II, 6.4 mg, 15 pts; Group III, 12.8 mg, 15 pts; Group IV, 25.6 mg, 38 pts; Group V, 33.3 mg, 70 pts; Group VI, 50.0 mg, 38 pts. Ages ranged from 30 to 70 years (mean 60 +/- 1). Coronary angiography was done at 30 min and 1 h. In patients with TIMI grades 0 and 1, reperfusion was accomplished after 1 h in 22% of Group I, 50% of Group II, 64% of Group III, 70% of Group IV, 67% of Group V, and 74% of Group VI patients. Complications were hypotension, nausea and vomiting, bradycardia and bleeding at the puncture site. These findings suggest that clot-selective coronary thrombolysis can be induced in patients with EMI by means of human tissue-type plasminogen activator without concomitant induction of a severe systemic lytic state. The optimal dose for Japanese patients is considered to be 33.3-50.0 mg from the standpoint of reperfusion.