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Biomedical subjects

R F Evans

Publications and source records attributed to R F Evans.

13 recordsLinked to original sources

Randomized study of chemotherapy/radiation therapy combinations for favorable patients with locally advanced inoperable nonsmall cell lung cancer: Radiation Therapy Oncology Group (RTOG) 92-04.

PURPOSE: The purpose of this study was to compare the severity and distribution of the toxicities associated with the two different combinations of chemotherapy and radiotherapy. METHODS AND MATERIALS: This prospective randomized trial studied toxicities associated with induction chemotherapy followed by concurrent treatment (Arm 1) vs. immediate concurrent chemotherapy/radiotherapy (CT/RT) (Arm 2). Arm 1 consisted of vinblastine (VB), 5 mg/M2 I.V. bolus weekly, weeks 1-5 and cisplatin (DDP), 100 mg/M2 days 1 and 29, DDP 75 mg/M2, days 50, 71, and 92. Daily RT started on day 50; a total dose of 63 Gy was given in 34 fractions in 7 weeks. In Arm 2 RT started day 1; a total dose of 69.6 Gy was given in 58 fractions of 1.2 Gy bid, 5 days per week for 6 weeks with DDP 50 mg/M2 i.v. days 1 and 8, and oral VP-16 50 mg b.i.d. during the first 10 days of RT. DDP/VP-16 were repeated beginning day 29. Survival was used as the Phase II endpoint. RESULTS: Between July 1992 and February 1994, 168 patients were randomized; 162 evaluable patients had minimum follow-up of 20 months. Eighty patients were registered to Arm 1 and 82 to Arm 2. Pretreatment characteristics were distributed evenly. Arm 1 had significantly more Grade 4 hematologic toxicity (62%) than Arm 2 (33%) (p = 0.021). Acute nonhematologic Grade 3+ toxicity was also greater (p = 0.018) in Arm 2 than Arm 1 due mainly to esophagitis (38 vs. 6%; p < 0.0001). Grade 3+ late esophageal toxicity was 12% on Arm 2 compared to 3% on Arm 1 (p = 0.006). There were no differences between the two arms in compliance with protocol specifications for either RT or CT. At 1 year, 31.7% of patients had in-field progression on Arm 1 compared to 19.8% on Arm 2 (p = 0.042), but overall progression-free survival rates were nearly identical; 50 and 49% for Arms I and II, respectively, at 12 months. One-year and median survivals were 65% and 15.5 months on Arm 1 compared to 58% and 14.4 months on Arm 2. CONCLUSION: Whereas hematologic toxicity was greater in Arm 1, esophageal toxicity, both acute and late, was greater in Arm 2. Infield progression was lower in Arm 2, but overall progression rates were similar and there were no significant differences in survival between the two arms. A 3-arm randomized Phase III study is underway in the RTOG to compare sequential and concurrent CT/RT.

Antineoplastic Combined Chemotherapy Protocols↗

A conformal technique for irradiation of pituitary tumors.

We present a CT/MRI based conformal radiotherapy technique for irradiation of pituitary tumors. In this technique, the patient is treated with three isocentric non-coplanar 18 MV photon beams, with the patient in a natural supine position. The radiation ports are designed based on beam's eye view projections of the CT/MRI delineated target volume. This technique spares, completely from the primary beams, the lenses and retina, and a significant portion of the optic nerves, even for large pituitary tumors. The dose distribution in brain is comparable to coplanar are techniques for standard field sizes (5 x 5 cm2), but superior for larger field sizes (7 x 7 cm2). The beams in the present technique yield a low skin dose by avoiding beam overlap in entrance and exit regions, thus eliminating clinical hair loss. The treatments are easily set-up on the treatment machines, resulting in improved efficiency and accuracy.

Humans↗

Diagnosis and repair of familial diaphragmatic defects in golden lion tamarins.

Diaphragmatic defects were identified in 11 of 130 golden lion tamarins. Seven of the cases were found at necropsy (52 tamarins) and 4 were diagnosed by radiography (78 tamarins). When screening radiography revealed a thoracic mass, a barium series was indicated and either demonstrated loops of bowel within the thorax or suggested liver displacement by the cranial location of the intestine. In 1 case, pneumoperitoneum aided in the diagnosis, by showing liver displacement cranially in an eventration of the diaphragm. The 4 defects diagnosed clinically were successfully corrected surgically. The defects mainly involved the ventromedial to lateral aspect of the costal and sternal muscular portions of the diaphragms. Either a thin pleuroperitoneal sac remained or wide gaps were associated with herniation of abdominal contents into the thorax. Of the 11 affected tamarins, 10 were closely related and the other had no direct consanguinity. An autosomal recessive mode of inheritance was suggested, but other genetic factors may have been involved.

Animals↗

Rabbit hemoglobin biosynthesis: use of human hemoglobin chains to study molecule completion.

A cell-free protein-synthesizing system made from rabbit reticulocytes was used to incorporate (14)C-amino acids into hemoglobin. Electrophoretic analyses of the soluble products of this cell-free system revealed a fraction containing rabbit (14)C-alpha chains in addition to the rabbit (14)C-hemoglobin. The addition of isolated human hemoglobin beta chains to this system during active synthesis inhibited the release of newly synthesized rabbit (14)C-beta chains into solution from the ribosome fraction. This inhibition was possibly a result of hybrid hemoglobin formation between rabbit alpha and human beta chains. A model of hemoglobin construction in which soluble alpha chains are intermediates is suggested. These alpha chains may aid in the release of beta chains from the polyribosomes during the completion of the hemoglobin molecule.

Animals↗

Intravenous anesthesia and jet ventilation for laser microlaryngeal surgery.

Competition between otolaryngologists and anesthesiologists for the limited space of the airway results in compromised control for both concerns. The surgeon desires an unobstructed view, whereas the anesthesiologist must ensure adequate ventilation. The drawbacks of standard methods include inadequate airways, inadequate visualization, and operating room contamination from inspired gases. Since 1984, we have developed a technique utilizing jet ventilation delivered through a metal delivery system providing a relatively safe, ignition-free environment. A total intravenous anesthetic technique is used to avoid any environmental contamination. The newer short acting, high potency narcotic, sufentanil citrate, combined with a short acting muscle relaxant, atracurium besylate or vecuronium bromide, have made this technique an ideal one for our needs. The pulse oximeter provides an invaluable margin of safety. This technique has been employed in 36 microlaryngeal procedures performed on 21 patients with a uniformly smooth perioperative course and only one complication. The technique, possible pitfalls, and applications are discussed.

Anesthesia, Intravenous↗