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We administered radon (Rn) to rabbits by inhalation and examined changes in the lipid peroxide (TBARS) level, superoxide dismutase (SOD) activity, and membrane fluidity in various organs to clarify the therapeutic effects of Rn. The lipid peroxide level of the brain was significantly decreased immediately after Rn inhalation for 90 min in both the low concentration group (about 7 ∼ 10 kBq/liter) and the high concentration group (about 14 ∼ 18 kBq/liter) as compared with that in the control group. It further decreased in the low concentration group but slightly recovered in the high concentration group 2 h after inhalation. The lipid peroxide level of the lung showed no change immediately after inhalation but decreased significantly in both groups 2 h after inhalation. With regard to SOD activity in the brain and lung, only that in the brain showed significant increase in the high concentration group immediately after inhalation; no other change was observed. Membrane fluidity, especially the fluidity of membrane protein, was significantly increased in the brains of both groups immediately after inhalation, and that 2 h after inhalation in the lung was significantly increased in both groups. These findings suggest that the inhalation of Rn at Rn springs contributes to the prevention of brain disorders related to peroxidation reactions by promoting these physiologic changes.

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 (P0.01), 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 (P0.01) and 0.88 in the non-DM group (P0.01). The r values of the relation between (a/A)PO2 and (A-a)PO2 were -0.68 (P0.00) and -0.84 (P0.01), while those for the respiratory index were -0.87 (P0.01), and -0.93 (P0.01), 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.

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 saturing. The correspondence was better with slant suturing than flat suturing (P0.01). The IA in flat suturing was 49.0 +/- 2.0 (mean +/- SE) degrees versus 33.0 for ideal suturing (P0.01), 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 surgeon's arm (human engineering), while satisfying the surgeons inclination to take a large IA.

The artificial blood vessel of 5mm I. D. compound-braided by using two ply yarns of polytetrafluoroethylene and collagen is designed and manufactured by circular braider.The test tubes of about 50mm in length were implanted in the place of the right external iliac artery in line and in the right common carotid artery as an arteriovenous shunt to the right external jugular vein of an adult mongrel dog. Microknit tubes of 4mm I. D. and 50mm in length, polyester knitted vascular prostheses of Golaski Lab., Philadelphia, Pa., U.S.A., were implanted in the left side respectively as a control.Bleeding through the tubes at implantation was found less in the new designed tubes than in the Microknits. The specimen obtained two days after implantation showed; 1) test tube implanted in the right external iliac artery was found thrombosed at the sites of anastomoses, and 2) the other one implanted in the right common carotid artery was found free from thrombus formation, whereas no thrombus formation in the Microknit grafts either in the external iliac or in the common carotid arteries.Poor cuff formation and too much tension of the tube at implantation should be responsible for an early thrombus formation.

The choice of synthetic vascular prostheses for arterial reconstuction surgery should be based on the data evaluated in long term both experimentally and clinically.Stable and viable inner capsule for a period of long time leads implanted graft to maintain the desirable function as a substitute for blood vessel.In order to clarify the healing mechanism of implanted vascular prostheses, following pathology should be analized. 1) Healing process from the sites of anastomoses. 2) Dissemination of multipotential blood cells on inner capsule and 3) The influence of capillaries of intercapsular space between meshes.Healing process from the host artery is not simple extension of endothelial cells to inner capsule, but is the result of healing motion from exaggerated porosity at the sites of anastomoses. And this phenomenon is possibly influenced by the blood flow according to our observation scale of endothelial cell-encapsulation density.Dissemination of multipotential cells in flowing blood on inner capsule seems to be quite acceptable to get new endothelialized cell lining Further studies will reveal whether the origin of endothelial cells is from blood stream or development of cells from the sites of anastomoses.In regard to the intercapsular capillary communication, there are out-growing capillaries of vasa vasorum which are found on the specimen of 83rd postoperative day in the earliest, mostly near anastomotic lines. These openings were found under the scanning electron microscopic study and they were confirmed as vasa vasorum by microscopic examination of serial section.The ideal stable structure of inner and outer capsules is that the viable collagen fibers with in- and out-growing capillaries are filled in wide space between meshes.Very thin inner capsule and viable intercapsular structure are seen specifically in the use of high porous grafts.Specifications for vascular prostheses, such as knitted finly, thin-walled, soft, pliable, high porosity, efficient preclotting, comformability at anastomotic lines and no fraying when cut at any angle are fullfilled by the Weavenit, Milliknit and Microknit vascular prostheses.Indications for arterial reconstruction surgery became broad by using the high porous grafts; bypass graftings beyond inguinal ligament and knee crease and possibility for the clinical use of small caliber grafts for A-V shunt in hemodialysis and for coronary bypass operation.

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.

In the grafting operation of vascular prostheses, decision variables are tensile force (F) during pre-clotting and required time (t) for pre-clotting. An optimization problem is constructed which contains three objective functions; maximize the porosity (Q1) (to maintain initial porosity over a long period of time), minimize the porosity (Q2) after pre-clotting (to reduce bleeding from the vascular prosheses during grafting), and minimize the required time (t) for pre-clotting (to reduce required time for grafting). The following regression equations are formulated using experimental data: Q1=2850+8.7F and Q2=αexp(-0.038t) where α is 38 or 311 according to the sample blood A or B drawn from two dogs. The tensile force (F) is assumed to have no relation with porosity (Q2), thus enabling two-criterion decision making to be applied. The approaches of the three solution methods; e-constraint approach, goal programming and surrogate worth trade-off method, have also been applied. Consequently, the most effective approach is goal programming. The same solution is obtained for different blood samples A and B.

Graft-type copolymers composed of hydrophilic poly(hydroxyethyl methacrylate) (PHEMA) as a backbone and a small amount of hydrophobic poly(methylmethacrylate) (PMMA) as a long branch exhibit excellent thromboresistance. The interrelationship between the thromboresistance and microstructure of the graft-type copolymers as well as the water structure in the hydrated polymers has been investigated. It was concluded that both the structure of hydrophobic domain dispersed in the hydrophilic matrix and the water bound to the polymer may be responsible for the excellent thromboresistance of the graft-type copolymers.

Claudication is very nuisance to the patient who has a ischemic limb. Claudication itself does not mean immediate amputation of the limb, since the inconvenience of the patient depends more or less on the activity. Things are different in patient who has a severely ischemic limb.It often causes peripheral ulcers, gangrene and amputation. These are life threatening potentially, especially in the elderly; after amputation of a lower extremity, unexpected falls may cause severe injury and stressfull life of post-amputation rehabilitation can possibly lead to cardiopulmonary distress.The advantages of living limb over the artificial is so great that it is reasonable to try more active forms of arterial reconstruction for severely ischemic limb than would be suitable for claudication alone in the broad sense of preventive rehabilitation.We have a demonstrable case of a 30-year-old man who has successfully been recovered with arterial re-reconstruction from severely ischemic leg, suffering from Thromboangiitis Obliterans over the period of 3 years.He had his right lower extremity bypassed previously with a Wesolowski-Weavenit, 6mm in internal diameter, over the segmental stenosis of right popliteal artery for claudica tion, and right lumbar sympathetic ganglionectomy simultaneously.Claudication and ulcers with severe ischemic pain developed in right foot following short period of success.We successfully saved his right foot by arterial reconstruction of autovein bypass over occluded arterial tree, supplying enough blood to improve claudication and also to cure longstanding-ischemic ulcers, though he eagerly wanted his leg amputated because of severe pain.We strongly emphasize the role of arterial reconstruction surgery to get rid of ischemic conditions in the field of rehabilitation for ischemic limb.It does work on salvaging living limb, even in a short period of success.

Exposure of skin to CO2 causes local hyperaemia and increases the number and diameter of functioning cutaneous capillaries (Stein and Weinstein, 1942; Kowarschik, 1948; Disi, 1958; Witzleb, 1962). Lipid-soluble CO2 is absorbable into the body through the skin, so that the dissolved CO2 acts as a vasodilator of dermal capillaries (McClellan, 1963).

AS A RESULT of more than a decade of investigation in the field of replacement of defects within the cardiovascular tree, our group has been able to appreciate certain basic conclusions. The first accomplishment was the establishment of a relative scale of acceptability of all known arterial graft materials (Fig 1). It is of interest to note that the fabric prostheses in general do not enjoy ultimate healing fates significantly better than homografts in general.2With respect to small caliber arteries, the canine carotid homograft demonstrates a 50% patency rate in 90 days (Fig 2). On the other hand, equivalently small caliber arterial prostheses exhibit a 90% occlusion rate within 24 hours of implantation even when the superb microsurgical technique of Jacobson is employed (oral communication, April 1968).3 Methodical study of the factors influencing the healing of arterial prostheses allowed certain basic observations, such as the relationship between