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Biomedical subjects

E L Travis

Publications and source records attributed to E L Travis.

88 records · Page 5Linked to original sources
PubMed1982

Tolerance of retroperitoneal structures to intraoperative radiation.

In conjunction with the clinical development of intraoperative radiotherapy, a study was undertaken in dogs to define the tolerance of normal anatomic structures in the retroperitoneum to radiation delivered during operation. Twenty adult dogs were subjected to laparotomy and intraoperative 11 MeV electron irradiation in single doses ranging from 0.to 5000 rad. Animals were followed regularly with clinical observation, blood count, serum chemistries, pyelography, and angiography. Animals were sacrificed and autopsied at regular intervals up to 12 months following treatment to assess radiation-induced complications or tissue damage. Irradiation field in all dogs consisted of a 4 X 15 cm rectangle extending inthe retroperitoneum from the level of the renal vessels to the bifurcation of aorta and vena cava. The field included aorta, vena cava, inferior portion of left kidney, and distal portion of left ureter. No complications or histologic changes occurred in any animal given doses of 2000 rad, with a follow-up in excess of 18 months. A dose of 3000 rad was well tolerated, except for left ureteral occlusion in one animal. Mild vascular fibrosis was present inthe aorta and vena cava, and significant ureteral fibrosis developed by six months after doses of 4000 or 5000 rad. All animals that received 5000 rad died of radiation-related complications, including ureteral obstruction and rectal perforation. It was concluded that major vessels tolerate intraoperative irradiation well up to and including 3000 rad and that no clinically significant vascular problems develop after 4000 and 5000 rad, although some fibrosis does occur. The ureter and kidney appear to be the most radiosensitive structures inthe retroperitoneum, showing progressive changes at 300 rad or greater and showing the potential for serious complications after doses of 4000 rad or more.

Animals↗
PubMed1982

Tolerance of bile duct to intraoperative irradiation.

In order to determine the effects of intraoperative radiation therapy of the bile duct and surrounding tissues, seven adult dogs were subjected to laparotomy and intraoperative irradiation with 11 MeV electrons. Two animals were treated at each dose level of 2000, 3000, and 4500 rads. A single dog which received a laparotomy and sham irradiation served as a control. The irradiation field consisted of a 5 cm diameter circle encompassing the extrahepatic bile duct, portal vein, hepatic artery, and lateral duodenal wall. The animals were followed clinically for mor than 18 months after treatment, and autopsies were performed on dogs that died to assess radiation-induced complications or tissue damage. All dogs developed fibrosis and mural thickening of the common duct, which appeared by 6 weeks following irradiation and which was dose-related, being mild at low doses and more severe at high doses. Hepatic changes were seen as early as 6 weeks after irradiation, consisting of periportal inflammation and fibrosis. The hepatic changes appeared earliest at the highest doses. Frank biliary cirrhosis eventually developed at all dose levels. Duodenal fibrosis appeared in the irradiation portal, being most severe at the highest doses and in some animals resulting in duodenal obstruction. No changes were observed in irradiated portions of portal vein and hepatic artery at any dose level. It was concluded that intraoperative radiation therapy delivered to the region of the common duct leads to ductal fibrosis, partial biliary obstruction with secondary hepatic changes, and duodenal fibrosis if bowel wall is included in the field. Clinical use of intraoperative radiation therapy to the bile duct in humans may require routine use of biliary and duodenal bypass to prevent obstructive complications.

Animals↗
PubMed1981

Effect of cyclophosphamide or x-rays on spontaneously occurring metastases from tumors transplanted into the tails of mice.

A spontaneous metastases model in mice is being used to test the efficiency of various treatments in eliminating metastases. Solid tumors were transplanted into the tails of mice and removed by tail transection when they had grown to a 4- to 5- or 6- to 7-mm mean diameter. Subsequently, 70 to 95% of mice not given other treatment developed metastases in the lungs or in regional lymph nodes (lumbar sacral region), or in both sites. The present paper reports the effects of whole-body or partial-body treatment on these metastases. The treatments, which started at the time of surgical transection of the tail, included a range of single or fractionated doses of cyclophosphamide (CTX) or X-rays given either to the whole body or locally to the lungs only. CTX reduced the incidence of metastases in both sites although the incidence of lung metastases was reduced by smaller doses of CTX than that of the lumbar sacral metastases. Whole-body irradiation of 6 grays (600 rads) had no effect on the incidence of metastases, whereas local irradiation of the lungs with single doses of 14.5 or 20 grays reduced the number substantially, as did 95 mg or more of CTX per kg. Thus, CTX or radiation reduced the incidence of lung metastases in a system where metastases developed from cells seeded from a primary tumor rather than from a cell suspension injected into the tail vein.

Animals↗
PubMed1978

The effect of the radiosensitizer misonidazole on motor nerve conduction velocity in the mouse.

The clinical use of misonidazole as a hypoxic cell radiosensitizer is at present limited by its neurotoxicity at high doses (Urtasun et al., 1977; Dische et al., 1977). An in vivo neurological end point, viz. measurement of nerve conduction velocity, has been developed to examine sensitizer action. Conduction velocity in mice was measured as a function of time after a single dose of misonidazole and as a function of drug dose. Doses greater than 0.33 mg/g produced significant transient reductions in velocity. The time course of the reduction in velocity closely followed the uptake/excretion profile of misonidazole from blood serum.

Action Potentials↗
PubMed1976

Unusual postirradiation sarcoma of chest wall.

This paper reports a sarcoma of the chest wall following postoperative radiation therapy for breast carcinoma. A total of 9346 rads was delivered at a 2-cm tissue depth from two treatment courses separated by a five-year interval. The sarcoma appeared 16 years following the initial radiation course. The existence of two mesenchymal elements in the lesion led to the final diagnosis of malignant mesenchymoma. Criteria for evaluating a possible radiation-induced malignancy are discussed.

Breast Neoplasms↗
PubMed1975

Radiographic technic, safety, and interpretation in the newborn nursery.

The technic and safety aspects of the radiographic evaluation of neonates with RDS are discussed. A study of radiographs taken in an intensive care nursery revealed that densitometric measurements are helpful in distinguishing changes in lung aeration from changes in radiographic quality. The radiation exposure to neonates was 5.1 (SD 2.3) mR per film and 44.9 (SD 39.7) MR per neonate. Limited chromosomal studies revealed no detectable abnormalities. The radiation exposure to the staff was minimal. The low-radiation exposure to the staff and neonates is the result of careful attention to radiation hygiene.

Absorptiometry, Photon↗