Kei Yamashiro

Clinical Study Regarding the Anatomical Structures of the Right Atrial Isthmus Using Intra-Cardiac Echocardiography: Implication for Catheter Ablation of Common Atrial Flutter

Background: The construction of complete bi-directional block in the isthmus (ITH) between the tricuspid annulus and inferior vena cava by radiofrequency energy (RF) applications is sometimes hampered due to anatomical problems such as a thick isthmus or aneurysmal pouch in patients with common atrial flutter (AFL).Methods and Results: Fifteen patients were referred for RF ablation of AFL. The anatomical thickness of the right atrial ITH, diameter of the right atrium and thickness of the right atrial free wall were determined using intracardiac echocardiography (ICE), along with the endocardial electrogram recordings at the ITH. RF was applied at the ITH to create a transmural incision to treat the AFL. A significant parallel relationship between the maximum amplitude of the atrial electrogram and the thickness of the ITH, was observed. When the maximum amplitude of the atrial electrogram at the ITH exceeded 1.5 mV, the thickness at the ITH was approximately larger than 5 mm.Conclusions: Using ICE, the precise measurement of the anatomical structures in the heart, including the ITH, was feasible. From the amplitude of the atrial electrogram, a deduction of the thickness at the ITH was possible, which is indispensable information for the appropriate selection of the RF devices.

Demonstration of fragments with thyroid stimulating activity from Thyroid stimulation blocking antibodies-IgG molecules by papain digestion

Thyroid stimulation blocking antibodies (TSBAb) inhibit TSH action and may have a role in the pathogenesis of hypothyroidism. In order to study the relationship between blocking and stimulating activities we have examined the biologically active fragments in TSBAb‐IgG molecules after papain digestion.

Mechanism of the Augmentative Effect of High Polyethylene Glycol (PEG) Concentrations on the Thyroid Stimulating Activity in TSAb-IgG Using a Porcine Thyroid Cell Assay

We previously demonstrated that high polyethylene glycol (PEG) concentrations (5% PEG) significantly augmented cAMP production in response to TSAb-IgG using the porcine thyroid cell (PTC) assay. The mechanism of the stimulatory effect of 5% PEG on cAMP production was examined by a two-step incubation with PTC. TSAb-IgG was preincubated with or without addition of 5% PEG in the PTC assay for 2.5 hr (1st incubation) and separated PTC was re-incubated with fresh Hanks buffer for 5 hr (2nd incubation). cAMP production in the 1st incubation medium by co-incubation of TSAb-IgG and 5% PEG for 2.5 hr was significantly increased (3.3-fold) compared to that without 5% PEG. When the cAMP content in PTC and the incubation medium were compared in the same volume of incubation medium after co-incubation of TSAb-IgG and 5% PEG for 2.5 hr, cAMP contents in PTC were about 7-fold higher than that in the incubation medium, and this ratio did not change in the incubation medium of TSAb-IgG without 5% PEG. Similar increases in cAMP contents in PTC (6.6-fold) compared to the incubation medium were also observed with bTSH, although there was no augmentative effect of 5% PEG on cAMP production by bTSH in either the incubation medium or PTC. When PTC, which had been preincubated with normal-IgG and 5% PEG in the 1st incubation, was re-incubated with TSAb-IgG in the 2nd incubation medium, cAMP production by TSAb-IgG was not stimulated by 5% PEG. The augmentative effect of 5% PEG on cAMP production by TSAb-IgG was observed whenever 5% PEG and TSAb-IgG were co-incubated in either the 1st or 2nd incubation. However, no stimulatory effect of 5% PEG on bTSH was observed. These results suggested the stimulatory effect of 5% PEG on TSAb-IgG-stimulated cAMP production may be due to the increase of binding or incorporation of TSAb-IgG into the membranes of PTC compared to TSH.

[Percutaneous endoscopic gastrostomy in patients with swallowing difficulties--home care and long-term result].

We studied the possibility of home care of patients who are unable to swallow. Postsurgical complications during the short term (within a week), medium term (within a month) and long term (more than a month) were recorded along with survival time. We also retrospectively studied the number of patients who were discharged after percutaneous endoscopic gastrostomy from November 1989 to March 1995. The percentage of patients with short-term postsurgical complications was 12.1%. Vomiting was the most frequent complication during the medium term and the long term. The weekly rate of complication development (total complications number/total survival time) was highest in the short term and decreased year by year. It was lower in those who were discharged from the hospital than in those who were not discharged. The average survival time was 460.2 days (544.7 days: home care group, 419.0 days: hospital group). The one-year survival rate was 58%, and the two-year survival rate was 36%. One third (32.8%) of patients were cared for at home after gastrostomy (average duration of care at home: 338.5 days) and the average duration of care at home as a percentage of survival time was 58.8%. We conclude that Percutaneous endoscopic gastrostomy can improve the quality of life of patients who are unable to swallow, and may allow them to be cared for at home.