The acceleration of cosmic-ray protons in the supernova remnant RX J1713.7-3946.

Protons with energies up to approximately 10(15) eV are the main component of cosmic rays, but evidence for the specific locations where they could have been accelerated to these energies has been lacking. Electrons are known to be accelerated to cosmic-ray energies in supernova remnants, and the shock waves associated with such remnants, when they hit the surrounding interstellar medium, could also provide the energy to accelerate protons. The signature of such a process would be the decay of pions (pi(0)), which are generated when the protons collide with atoms and molecules in an interstellar cloud: pion decay results in gamma-rays with a particular spectral-energy distribution. Here we report the observation of cascade showers of optical photons resulting from gamma-rays at energies of approximately 10(12) eV hitting Earth's upper atmosphere, in the direction of the supernova remnant RX J1713.7-3946. The spectrum is a good match to that predicted by pion decay, and cannot be explained by other mechanisms.

[A randomized comparative study of surgical adjuvant chemotherapy using 5-fluorouracil and dl-leucovorin with CDDP 5-FU and dl-leucovorin for colorectal cancer].

A randomized comparative study of surgical adjuvant chemotherapy using dl-leucovorin (dl-LV) and 5-fluorouracil (5-FU) (FL-therapy) with CDDP, 5-FU, and dl-LV (PFL-therapy) was conducted. The following were the administration schedules: Arm A was 13 mg/m2 of CDDP, 300 mg/m2 of 5-FU, and 30 mg/body of dl-LV for 5 consecutive days and arm B was 300 mg/m2 of 5-FU and 30 mg/body of dl-LV for 5 consecutive days. Both regimens were followed by biweekly administration of the same dose of dl-LV and 5-FU in outpatients. Arm A was started at the 26th postoperative day and arm B at the 21st day on average. Some 26 cases composed of 11 cases of arm A and 15 cases of arm B completed the administration schedules. Only one case in arm A was complicated by local recurrence around 35 months after operation. Major toxicities were anorexia and neutropenia. Both toxicities were seen more in arm A than in arm B, showing complete recovery in all cases. These data suggest that PFL-therapy and FL-therapy seem to be possible and promising surgical adjuvant therapies for advanced colorectal carcinoma.

A case of popliteal cystic degeneration with pathological considerations.

Adventitial cystic degeneration of the popliteal artery is seldom encountered; only 39 cases have been reported up to now in Japan. The pathogenesis of this disease remains controversial, and the authors describe a case in which the pathological findings differed from cases reported in the previous literature. The subject was a 74-year-old man admitted to our hospital complaining of intermittent claudication. The characteristic findings of cystic degeneration of the popliteal artery were uncovered by contrast-enhanced computed tomography (CT) and duplex sonography. The contrast-enhanced CT showed a low-density area and duplex sonography revealed a multi-lobulated low-echoic lesion. The Doppler signal of the low-echoic lesion could not be detected. While some cysts were found in the adventitia, they were mainly located in the media. The media also showed a remarkable decrease of smooth muscle cells and a prominent mucinous degeneration that had occurred circumferentially. These findings suggest that the medial degeneration noted had occurred prior to cystic formation. Because of this and other findings, we recommend the use of the term cystic degeneration of the popliteal artery in addition to the term cystic adventitial disease of the popliteal artery.

[Conservative treatment of acute deep vein thrombosis of lower extremities].

To evaluate conservative treatment for acute deep vein thrombosis (DVT) of lower extremities, 56 limbs of 53 patients (29 men and 24 women, age ranging 20 to 77 years, mean age of 50.1 years) were reviewed. Only three patients underwent thrombectomy of restricted iliac venous regions by Fogarty catheter within 24 hours of the onset and their symptoms were relieved immediately after operation with good follow-up condition. Forty-five limbs were treated conservatively. Among 45 limbs, 15 limbs were treated within 7 days of symptom's onset using heparin and urokinase for 6-10 days followed by oral anticoagulant. Forty-seven percent of the patients were freed from their symptoms within one year. However 30 limbs received conservative therapy after 7 days of the onset showed 23% recovery from their symptoms within one year and in extensive thrombosis recovery was only 14%. We concluded that conservative treatment for DVT was effective if it was started within 7 days of the onset, and thrombectomy of ilio-femoral regions might be more effective than conservative treatment under the same condition.

[Transanal Doppler ultrasound for prevention of colonic ischemia following abdominal aortic reconstruction].

Colonic gangrene is a fatal complication following aorto-iliac reconstruction. Preservation of a sufficient blood flow through both the inferior mesenteric artery (IMA) and the internal iliac artery (IIA) is believed to be important in its prevention. The transanal Doppler ultrasound technique is a new method to explore intraoperative pelvic hemodynamic changes. After identifying the artery responsible for rectal perfusion and then estimating the collateral rectal blood supply which was derived from the superior mesenteric artery (SMA) after aortic clamping, the treatment for the IMA and the IIA was determined. Out of 49 cases of abdominal aortic aneurysm (AAA), 43 cases (88%) were considered to be SMA-dominant, with ligation of the IMA and the IIA being feasible. The IMA and bilateral IIAs could be ligated uneventfully in 14 AAA cases. And, in fact, the reconstruction of the IMA was performed in only 2 cases (4%). Among 21 cases of aorto-iliac occlusive disease (AIOD), 8 cases (38%) were found to be SMA-non-dominant, which suggests a greater importance in the preservation of intrapelvic circulation in AIOD than in AAA. Adequate intraoperative monitoring, by the transanal Doppler ultrasound technique, is essential for the successful prevention of postoperative colonic ischemia.

Intra-operative monitoring of the pelvic circulation using a transanal Doppler probe.

The authors have developed a new device to examine the pre-, intra-, and postoperative pelvic blood flow, consisting of a plastic rectoscope with a commercially available 10 MHz flat Doppler probe mounted at the tip surrounded in use by a thin, acoustic gel filled condom and inserted transanally. Blood flow in the superior rectal artery can easily be detected in this way through the posterior wall of the rectum. The authors have used this technique in 70 patients, 49 undergoing abdominal aortic aneurysmectomy and 21 aorto-femoral bypass surgery. In all cases following clamping of the infrarenal aorta a synthetic bifurcated graft was anastomosed usually to the aorta using an end-to-end or end-to-side anastomosis. Immediately after application of the aortic clamp the Doppler recorder was started in order to determine the time when rectal blood flow reappeared. In the superior mesenteric artery dominant group, a good pulse wave was seen within 15 min of clamping and 88% of the aneurysm and 62% of the aorto-iliac patients fell into this group. Fourteen patients in this group underwent triple vessel ligation (bilateral internal iliac and inferior mesenteric arteries) without any postoperative colonic ischaemia. In an additional study consisting of eight patients with vasculogenic impotence and/or hip claudication, the effectiveness of surgery was assessed by the increase in amplitude of the Doppler signals following reconstruction of the internal iliac artery. Following successful internal iliac reconstruction, an improvement in the amplitude of the waveform could be observed and followed postoperatively. In conclusion, the transanal Doppler probe can be used to follow the adequacy of the pelvic circulation allowing safer aorto-iliac and aorto-femoral surgery.

The assessment of pelvic circulation after internal iliac arterial reconstruction: a retrospective study of the treatment for vasculogenic impotence and hip claudication.

The standard surgical treatment of vasculogenic impotence or hip claudication involves repairing vascular lesions, especially in the internal iliac arteries. It is difficult, however, to make a definite diagnosis or an accurate judgement of the therapeutic effects of this treatment due to the trouble in ruling out any other disorders. During the last five years, 19 patients with impotence and associated apparent internal iliac artery stenosis or occlusion and 2 patients with hip claudication, underwent internal iliac arterial reconstruction. The patients' ages ranged from 37 to 70 with a mean age of 63.7 and the main procedure performed in all patients was aorto-iliac to femoral bypass grafting, or abdominal aortic aneurysmectomy. A retrospective study revealed that 74 per cent of those treated regained penile erectile activity postoperatively, and that hip claudication disappeared completely in all cases. One of the patients received percutaneous transluminal angioplasty (PTA) for the treatment of vasculogenic impotence, after which his postoperative penile brachial pressure index (PBPI) improved, demonstrating a statistically significant difference compared to the preoperative value. Trans-anal Doppler measurement also proved useful in providing complication-free perioperative understanding of pelvic circulation.

Use of transanal intubation in Doppler ultrasonic assessment of blood flow of the rectal wall.

To date, tentative early use of these newly designed Doppler probes to evaluate intestinal or pelvic blood flow, using transanal intubation, seems to be considerably effective and has produced easily obtainable and repeatable results preoperatively, intraoperatively and postoperatively. No complications using this technique have yet been observed.

A new treatment for ischemic ulcers: foot bath therapy using high oxygen soluble fluid.

We devised a new treatment for ischemic ulcer in which the diseased foot is soaked in perfluorodecalin, a fluorocarbon. Pure oxygen bubbles emerge from the perfluorodecalin, and dissolved oxygen levels reach 35% by volume within 60 minutes. The solution is placed in a bath once or twice a day for 2-3 hours and pure oxygen is allowed to bubble through it (3-5 1/min). Nine patients were treated by this technique. Drugs which seemed to have an effect on ischemic ulcers were not used during the treatment. Ischemic ulcers in three patients (5 X 5 mm, 23 X 6 mm and 10 X 5 mm) healed completely within two weeks and there were no recurrences. In six patients, the ulcers showed 30-70% reductions in size within 4 to 14 days. Four of them later underwent arterial reconstruction, which resulted in complete healing of the ulcers. In two patients, the ulcers reverted to their former size 6 to 12 months after the cessation of perfluorodecalin bath therapy.

Popliteal vein entrapment caused by the third head of the gastrocnemius muscle.

Three cases of the popliteal vein entrapment syndrome have been encountered during the past 3 years. The third head of the gastrocnemius muscle appeared to be the cause of this rare condition with the vessels in their normal position. Partial resection of the excess muscle was sufficient to relieve symptoms.

Pathological considerations of reoperative vascular patients.

Since vascular disease is always progressive and a perfect vascular prosthesis has yet to be developed, postoperative complications are almost inevitable. In this paper, case histories of those who had to have a second operation or, in other words, re-operated patients, have been examined to ascertain the current problems in vascular surgery. Of 176 vascular reconstructive operations performed between January 1, 1980, and December 31, 1986, 29 re-operations were performed on 19 patients (mean age: 64 years; 15: male). The incidence of late graft failures was 8.4% and, of these, anastomotic aneurysms seemed to be the most serious complication (3.1% incidence rate). Late graft failures included intimal hyperplasia, occurring within two years in five cases, and four cases of progressing atherosclerosis, which appeared three years after the initial operation. In all cases of anastomotic aneurysm, arterial wall failure, possibly combined with the changing of implanted grafts, was considered to be related to the false aneurysmal formation. Knitted Dacron demonstrated susceptibility to atherosclerotic progression, whereas the major fault of polytetrafluoroethylene (PTFE) grafts was the insufficiency of the anastomotic diameter. In conclusion, it was revealed that many factors can provoke late graft failure. Improvement of long-term patency seems to be achieved by a more increased understanding of the pathological meaning of these factors, along with the proper application of medical techniques suited to the causes of vascular obstruction.