Frequency Dependent Shortening of Conduction Time through the Reentrant Pathway during Transient Entrainment of Ventricular Tachycardia

In a patient with nonischemic ventricular tachycardia (VT), VT was entrained and the conduction time from the pacing site to the entrained local electrogram showed a rate dependent shortening and its degree affected by the pacing site. The QRS complex, which was entrained by the last pacing stimulus, was constant and identical to that of VT and no rate dependent facilitated conduction was observed when the heart was paced at similar paced cycle lengths during sinus rhythm. As the mechanism of the shortening of the conduction time through the reentrant circuit, a shift of the entrance seems most likely.     

Spread of subarachnoid hyperbaric amethocaine in pregnant women

In order to examine how the gestational period influences thespread of spinal anaesthesia, we have measured the extent ofspinal block produced by hyperbaric amethocaine 8 mg in 90 women.The patients were allocated to one of five groups accordingto the gestational period: non-pregnant group (n = 17), firsttrimester group (6–12 weeks, n = 14), second trimestergroup (13–24 weeks, n = 26), third trimester group (25–36weeks, n = 15) and term group (37–41 weeks, n = 18). Maximumcephalad spread of analgesia was significantly higher in thesecond trimester (median T3 (range T9–C6)), third trimester(T3 (T4–C7)) and term groups (T2.5 (T4–C8)) thanin the non-pregnant (T4 (T8–T2)) and first trimester groups(T4 (T11–C7)). We found that not only term pregnancy butalso second and third trimester pregnancies enhanced the spreadof spinal anaesthesia, and that first trimester pregnancy didnot affect the spread of spinal anaesthesia.     

The Efficacy and Diagnostic Significance of Sodium Thiosulphate Solution Spraying After Iodine Dyeing of the Esophagus

Abstract: Spraying with Sodium Thiosulphate Solution (STSS, Detoxol®) is reported to be useful in reducing the side effects of Iodine dyeing on the esophagus. In order to determine the optimal concentration of STSS and its efficacy, STSS was administered in the following concentrations. Group A: 10% (Original Solution), Group: B 5%. Group C, 2.5%. Group D: 1.7% and Group E: saline with no STSS, and a questionnaire was conducted to assess the side effects. The results showed that the higher the concentration, the less frequent and short lasting the side effects were. The effects of STSS on diagnostic efficacy was also evaluated. After spraying with STSS, the 2.5% solution removed iodine gradually but there were differences in discoloration among the various degrees of inflammation. When iodine dyeing was repeated, clear images with a good contrast were obtained. Excess iodine was neutralized and details of the surface and vascular pattern were more readily observed. Spraying with STSS seemed to increase the diagnostic ability of the procedure.     

Immunoreactivity to M2 proteins in antimitochondrial antibody-negative patients with primary biliary cirrhosis

Abstract Although antimitochondrial auto-antibodies are characteristically present in the serum of patients with primary biliary cirrhosis (PBC), there is a discrepancy between the positivity for antimitochondrial antibody (AMA) and that for anti-M2 auto-antibody. In an attempt to explain the discrepancy, this study investigates the relationship between the AMA titre, determined by indirect immunofluorescence, and immunoreactivity to four inner mitochondrial membrance proteins (M2 proteins) with molecular weights of 70, 50, 47, and 40 kDa in 129 patients with PBC. Antimitochondrial antibody positivity was identified in 114 (88%) of 129 patients with clinically and histologically confirmed PBC. There were no significant differences between the AMA-negative and AMA-positive groups in clinical characteristics or histologically determined disease stage. Immunoblot analysis showed that all patients had anti-M2 auto-antibodies to one or more of the four M2 proteins. Nine (60%) of the 15 AMA-negative patients had antibodies to only one M2 protein (either 70 or 47 kDa). In contrast, 34 (53%) of the 64 patients with high AMA titres ( 1: 320) had antibodies to all four M2 proteins. There was a significant rank correlation between the AMA titre and the number of antibodies to M2 proteins ( P < 0.01). These findings indicate that the AMA titre is not influenced by the immunogenicity of M2 protein but by the number of M2 proteins that elicit an antibody response and that decreased immunoreactivity to M2 proteins may induce AMA negativity in PBC serum samples.     

Cutting Balloon Angioplasty for a Restenosis Lesion at the Distal Anastomosis of a Saphenous Vein Graft

We successfully performed cutting balloon angioplasty for a restenotic lesion involving the distal saphenous vein graft (SVG) anastomosis that had developed within 1 month after conventional balloon angioplasty. We considered that cutting balloon angioplasty, which has been considered to produce less vascular injury, could be a viable choice for the treatment of a lesion at the distal anastomosis of an SVG.     

Deficiency of Testosterone Associates with the Substrate of Atrial Fibrillation in the Rat Model

Background: Since the prevalence of atrial fibrillation (AF) increases progressively with aging, especially in men, we hypothesized that testosterone might affect the occurrence of AF.
Methods and Results: We examined the electrophysiological properties of the atria in isolated-perfused hearts of sham-operated male (SM), female (SF), orchiectomized male with and without administration of testosterone (ORCH-T and ORCH), and ovariectomized female (OVX) Sprague-Dawley rats. An electrophysiological study revealed that repetitive atrial responses induced by electrical stimuli significantly increased in ORCH rats without changes in other electrophysiological properties and were abolished by administration of testosterone. To investigate the underlying mechanisms, we evaluated the expression level of calcium-handling proteins. In ORCH rats, the immunoreactive protein level of ryanodine receptor type 2 (RyR2) and sodium–calcium exchanger significantly increased as compared with SM and ORCH-T rats without alterations in the level of FK506-binding protein (FKBP12.6), sarcoendoplasmic reticulum Ca-ATPase, and phospholamban. Immunoprecipitation analysis demonstrated decreased binding of FKBP12.6 to RyR2 in ORCH rats, which was prevented by testosterone. In contrast, the expression levels of these proteins showed no significant differences between SF and OVX rats.
Conclusion: Deficiency of testosterone was arrhythmogenic in rat atria possibly through less binding of FKBP12.6 to RyR2, which could induce feasible calcium leakage from the sarcoendoplasmic reticulum. These results would explain, at least in part, the increase in the prevalence of AF in accordance with the decline of testosterone particularly in elderly men.     

Experimental Study About Removal of the Implanted Tined Polyurethane Ventricular Lead by Radiofrequency Waves Through the Lead

Polyurethane pacemaker leads are widely used nowadays. However, only a few studies have been done to investigate the fixation mechanism of polyurethane leads. To elucidate how pacemaker leads are fixed at the early phase after implantation, polyurethane-insulated tined ventricular leads were implanted in seven mongrel dogs. One to 4 months later, tips of the leads were anchored among the trabeculae and the distal part of the leads were encapsulated by whitish fibrous tissue. It was found that not organized thrombi, but cell reaction with various stages of inflammatory cells was responsible for forming the fibrous tissue. We attempted to remove the lead by delivering radiofrequency wave through the lead. However, no lead could be removed.     

Clonal and non-clonal karyotypically abnormal cells in haemophagocytic lymphohistiocytosis

We studied chromosomes in bone marrow (BM) or peripheral blood cells of nine patients with haemophagocytic lymphohistiocytosis (HLH); three of them had a family history of HLH and four others underwent concurrent Epstein-Barr virus (EBV) infection. In addition to a large population of normal mitotic cells, karyotypically abnormal clonal cells were found in two patients, abnormal clonal cells and a nonclonal (single) abnormal cell in one, and nonclonal abnormal cells in three. All the six patients with chromosome abnormalities died of progressive disease; one of them also had EBV infection and EBV-associated clonal proliferation. Two of three patients with EBV infection and only normal mitotic cells in BM completely recovered from the disease.
Although HLH did not show histological and/or haema-tological evidence of a neoplastic disease, clonal chromosome abnormalities and the fatal clinical outcome found in some of the patients suggest that the disease may be heterogenous and include malignancy. HLH patients with karyotypically abnormal clonal cells in BM should warrant more intensive chemotherapy than that presently being applied to them and should be considered as candidates for BM transplantation.