A Report on Experiments with Toyo ‘s Super-Gus-Permeable Hard Contact Lens: Paper presented at the International Contact Lens Congress,Fiji, July 1978.

Among the recent developments in the field of hard contact lenses, attention has been focused on a new type of lenses with high oxygen permeability. In 1977 the staff of the research division of the Toyo Contact Lens Co. Ltd succeeded in developing a new polymer with extremely high oxygen permeability based on an entirely new monomer made of esterifies methacrylic acid. They have named this new material ‘PHCL’, denoting a gas permeable hard contact lens. The PHCL has the following two primary features. The first feature lies in its excellent gas permeability. The permeability of the PHCL is measured to be 1.4×10^--¹⁰ml. cmlcm².sec.mmHg., which is about 2.5 times the permeability of other gas permeable hard contact lenses and about twice that of 2–Hema polymers. The second feature is the good wettability of the new material. The wettability is usually estimated by the contact angle. The contact angle of the PHCL is measured to be 23°, showing a remarkable improvement from the contact angle of PMMA which is about 63“. These two features will definitely contribute to the physiological integrity of the cornea and the comfort in wearing contact lenses. Our report includes the comparison of the PHCL with other gas permeable hard contact lenses and several soft contact lenses with respect to the following points: 1) reduction of glycogen granules in rabbits' eyes; 2) histological studies by HE staining; 3) corneal thickness changes measured by pachornetry with human eyes. The data indicates superior quality of the PHCL to other materials in terms of maintaining the normal metabolism and physiology of the cornea.     

Clinical Evaluation of Endoscopic Ultrasonogrphy in Diagnosis of Submucosal Tumor of the Upper Alimentray Tract

Abstract: The usefulness and the problems of endoscopic ultrasonograpy (EUS) in the diagnosis of submucosal tumors (SMT) of the upper alimentary tract were evaluated in this study. EUS was carried out in 86 cases with SMT of the stomach. Tumors of 13 cases was confirmed histologically (leiomyoma in 7 cases, leiomyosarcoma in one, lipoma in 2, gastric cyst in one, aberrant pancreas in one and Schwannoma in one case). In only one out of 22 cases with SMT of the esophagus, the tumor was surgically resected and a pathological examination revealed leiomyoma EUS was useful in estimating the histological origin of SMT by observation of the relationship between the location of the tumor and each layer in the gastric or esophageal wall. However, it was imposible to differentiate leiomyoma from leiomyosarcoma in myogenic tumors through the echoic pattern of the tumor by EUS alone at the present time. EUS was also useful in distinguishing the cause of extragastric compression showing similar findings with SMT, which could not be clarified by X-ray or endoscopic examination. In fact, organs compressing the stomach were easily clarified by EUS. It was decided that EUS should be performed in all cases whenever there is any doubt of SMT existing after an X-ray or endoscopic examination.     

Quantitative Analysis of Concealed Conduction into Accessory Atrioventricular Pathways in Wolff-Parkinson-White Syndrome

Concealed conduction is demonstrated to occur in an accessory AV pathway (AP). To test the hypothesis that anterograde and retrograde concealed conduction in the AP would have different characteristics, 35 consecutive patients with single APs were studied. The anterograde or retrograde ERP of the AP could be determined in 23 of those patients. Anterograde concealed conduction in the AP was assessed in the first 13 patients with retrograde AP conduction (8 APs with retrograde conduction only and 5 with both directions) (group A). Retrograde concealed conduction in the AP was evaluated in the remaining 10 patients with anterograde AP conduction (6 APs with anterograde conduction only and 4 with both directions) (group B). The concealed conduction in the AP was quantified by determining the ERP of the AP using a “probe” extrastimulus (S_p) introduced in the opposite chamber. The ERP was determined both during conventional extrastimulus (S₁S₂ method; ERP_c) and during that with an S_p (S₁S_pS₂ method; ERP_p). The S_p was delivered before or after the last S₁ with various S₁S_p intervals. The ERP_p was determined at each S₁S_p interval. Three distinct patterns in concealed conduction in the AP were noted. In the first pattern, the ERP_p was always shorter than the ERP_c, whereas the reverse relation was noted in the second pattern. The third pattern showed a combination of the two. In group A, only the first pattern was noted. In group B, the first, second, and third patterns were noted in 4, 2, and 4 patients, respectively. The first pattern was noted only in septal APs and the second and third were seen only in left free-wall APs. The second pattern was seen in patients with retrograde AP conduction, whereas the third one was mainly noted in patients without retrograde AP conduction. These observations indicate that anterograde and retrograde concealed conduction in the AP have different characteristics. Shortening of the ERP_p might be due to the “peeling back” phenomenon, and its lengthening might be caused by the presence of the inhomogeneous refractory periods of the AP. (PACE 1997; 20[Pt. I]:1342-1353)     

Endoscopy-Assisted Radiofrequency Ablation Around the Coronary Sinus Ostium in Dogs:

Endoscopy for Ablation Around the CS Ostium. Introduction : Radiofrequency ablation of the slow pathway can prolong atrioventricular (AV) nodal properties and RR intervals during atrial fibrillation (AF) in many patients with AV nodal reentrant tachycardia. However, it is not well elucidated whether these changes are related to the presence of dual AV nodal pathway physiology. The aim of this study was to evaluate changes of AV nodal properties and RR intervals during AF caused by ablation of two specific areas in dogs.
Methods and Results : Assisted by fiberoptic endoscopy, linear lesions were created between the coronary sinus ostium and tricuspid valve annulus (area 1) or posterior to the ostium (area 2) in 15 dogs. Three additional dogs served as controls. The measurements were made under autonomic blockade. Catheter ablation could be assisted in all dogs by means of endoscopy. Linear lesions were confirmed at autopsy. AV nodal parameters and RR intervals showed no overall changes. Individual data showed that ablation of area I resulted in modification of AV nodal properties in 54.5% (facilitation in 363% and inhibition in 18.2%), whereas ablation of area 2 induced changes in 50% (facilitation in 10% and inhibition in 40%). The RR intervals were shortened in 33.3% and 20% and prolonged in 44.5% and 40% after ablation of areas 1 and 2, respectively. The RR intervals during AF correlated well with the Wenckebach cycle length and the AV node functional refractory period before and after ablation (r = 0.78 to 0.94, P < 0.01 for each).
Conclusions : Ablation of the two specific areas around the coronary sinus ostium was equally effective in modifying AV nodal properties and the ventricular response during AF without dual AV nodal pathway physiology. The ventricular rate to AF after ablation correlated well with the residual AV nodal properties.     

β-PLEATED SHEETS IN OLIGOPEPTIDE CRYSTALS

Many oligopeptide crystals show the β-pleated sheet structures. Both parallel and antiparallel chain pleated sheets are found, and also both ideal (flat) and heavily twisted sheets are found. The structural parameters, such as the T (NCα-C') angles, the torsion angles (φ and ø), the fiber axis periods, the hydrogen bond lengths, and the interchain spacings, are studied. Some of them deviate signifi cantly from those proposed by Pauling & Corey (Proc. Natl. Acad. Sci. US (1953), 39, 253–256). In the heavily twisted sheets, the twists are larger than those in the globular proteins, and each two neighboring chains are almost per pendicular with each other, preserving the β-sheet type hydrogen bond system. The torsion angles in the twisted sheets are rather close to those of the poly (L-proline) II helix. It also is discussed that the (NCαC) angles sometimes deviate by almost 5° from the standard value depending on the structures of the main and side chains.