Yoshiaki Komoto

Cancer mortality survey in a spa area (Misasa, Japan) with a high radon background

The 1952–88 cancer mortality records for inhabitants of the Misasa spa area, Japan, which has a high radon background, and a neighboring control area without any radon spa were analyzed (average outdoor Rn concentration: 26 mBq‐liter−1 in Misasa vs. 11 mBq‐liter−1 in the control area). Standardized mortality ratios (SMRs) for cancers of all sites were significantly lower among the inhabitants of both Misasa (male 0.538; female 0.463) and the control area (male 0.850; female 0.770), than in the whole Japanese population. Poisson regression analysis showed that the relative risks among the inhabitants of Misasa were significantly lower than in the control area for deaths from cancers of all sites (0.67) and stomach cancer (0.59). The relative risk of lung cancer death was also lower (0.55 times) in Misasa than in the control area, although the difference was not statistically significant. These results suggest that the linear no‐threshold hypothesis for radiation risk may not be valid for exposure to low doses of radon.

Elevation of Tissue PO2 with Improvement of Tissue Perfusion by Topically Applied CO2

Local absorption of CO2 was examined, by tissue gas analysis with medical mass spectrometry, in rabbits placed in a bath. The results obtained clearly showed that (1) Elevation of subcutaneous tissue PO2 was followed by elevation of PCO2 in the subcutaneous tissue. (2) Local absorption of CO2 through skin was confirmed by elevation of the levels of subcutaneous PO2 and PCO2 at the site exposed to CO2. (3) Tissue perfusion during the CO2 bath was moderately higher than that observed with tap water bathing. The mechanism of oxygen release into the tissue by CO2 bathing is thought to involve increased [H+] and PCO2 in the red blood cells, which shifts the hemoglobin dissociation curve to the right, thus facilitating oxygen release at the tissue level. There is, therefore a good possibility, that the improved tissue perfusion together with the increased oxygen in the tissue will favourably affect wound healing and chronic degenerative disorders, thus facilitating rehabilitation.

The surgeon's technical skill in suturing : an analysis of the actual suture tracks

Ideal suturing was defined as advancing a needle along its curvature (needle circle) to minimize tissue trauma, while placing the suture with its intended span and tissue bite in the expected place. Actual suture tracks were analyzed to find the keys to produce such suturing. Correspondence of those tracks to the ideal track was then determined by the span, the initial needle angle (IA) into the tissue, and the center of the needle circle. Eight surgeons with 4–7 years of experience produced 22 ideal sutures in two types of tissue simulants: The entrance and exit points of the needle were level in flat suturing, while the entrance point was slanted 45 degrees for slant suturing. The correspondence was better with slant suturing than flat suturing (P<0.01). The IA in flat suturing was 49.0±2.0 (mean±SE) degrees versus 33.0 for ideal suturing (P<0.01), while that in slant suturing was 35.5±1.9 (P: ns). In conclusion, the IA was the key to good results, and was optimized in slant suturing, which was instinctively utilized in practice by using forceps. The forceps avoided a derangement of suturing stemming from the configuration of the needle employed and from the range of motion of the surgeons arm (human engineering), while satisfying the surgeons inclination to take a large IA.

Pulmonary Oxygen Transfer Deficits of Diabetic Origin in Patients Undergoing Coronary Artery Bypass Grafting

The objective of this study was to determine the effects of a diabetic disposition on pulmonary gas exchange by examining 72 patients who underwent coronary artery bypass grafting (CABG), using the arterial/alveolar oxygen tension ratio [(a/a)Po2] as a criterion. Patients were divided into a diabetic (DM) group and a nondiabetic (non-DM) group. The postoperative blood gases and hemodynamic data measured when the blood glucose level was at a maximum on the day of CABG were used as the postoperative pulmonary gas exchange indices, and the physicians who managed these patients were unaware of this study. The preoperative (a/a)Po2 ratio was 0.66±0.03 (SE) in the DM group and 0.78±0.02 in the non-DM group (P<0.01), while the postoperative ratios were 0.42±0.03 and 0.52±0.03, respectively (P=0.01). The correlation coefficient (r) for regression analysis of the relation between the postoperative Pao2/Fio2 ratio and the postoperative (a/a)Po2 ratio was 0.99 in the DM group (P<0.01) and 0.88 in the non-DM group (P<0.01). The r values of the relation between (a/a)Po2 and (a-a)Po2 were −0.68 (P<0.00) and −0.84 (P<0.01), while those for the respiratory index were −0.87 (P<0.01), and −0.93 (P<0.01), respectively. Thus, pulmonary oxygen transfer was compromised before and after CABG in the DM group compared to the non-DM group. Moreover, the Pao2/Fio2, being the simplest pulmonary gas exchange index to calculate, was a reliable substitute for the (a/a)Po2 ratio during the early postoperative management of CABG patients.

Prosthetic Aneurysm in an Axillofemoral Dacron Bypass Graft

types of synthetic fibers. A number of publications have already appeared describing complications of graft dilation or rupture of prostheses secondary to yarn deterioration. 1-8 The following case report illustrates such yarn deterioration in an axillofemoral knitted Dacron graft. This case is reported to stress that patients bearing any type of vascular prosthesis should be observed throughout their lifetime for this complication.

Anastomotic rupture of aortic grafts.

Proximal suture line disruption is one of the severe complications of syn thetic vascular grafting for arteriosclerotic aortic disorders. The pathology of clinical and experimental cases revealed that a small bite of each stitch cut into the host aorta and became disrupted. Making each stitch as large as possible in the host aorta is the first procedural choice for aortic replacement surgery. Protecting the anastomotic line with a synthetic mesh cloth wrapping is prefer able.

Some Pathophysiological Aspects of Modified Human Umbilical Cord Vein Used as an Arterial Conduit

From the Institute for Thermal Spring Research, Okayama University, Misasa, Japan * From the Department of Pathology, Kagawa Medical School, Kagawa, Japan The modified human umbilical cord vein graft for peripheral vascular reconstructions has been used clinically in more than 900 implants all over the world because of its favorable biological, physical and chemical characteristics since it was first reported by Dardik et al. in 1976.’’2,3,4 As the number of cases increases, more attention is being paid to late complications, although minimal, related to the grafts and/or grafting, such as false or true aneurysm and thrombosis. Giodano and Keshishian reported three cases of aneurysm formation in implanted human umbilical vein grafts . 4

A new approach in evaluating the hemodynamics of ischemic legs by mass spectrometry: a preliminary report.

Mass spectrometry has been used for continuous in vivo measurement of tissue, blood, and respiratory gases since Brantigan and his colleagues’ developed the nonthrombogenic diffusion membrane patterned after Grode’s method.’ To evaluate tissue perfusion, mass spectrometry has also been used to measure cerebral, myocardial, and skeletal muscle gas tensions, both experimentally and clinically.’-’ The hemodynamics of peripheral arterial disease have been elaborated by plethysmography, thermography, impedance and Doppler devices, and radioactive clearance. Angiography is widely u6!~;L’. to diagnose obliterative arterial diseases, but the information provided by angiograms is relatively limited.