ABSTRACT
PURPOSE: Preoperative, high-dose radiotherapy for rectal cancer reduces local recurrence rates and improves overall survival. However, adverse effects in varying degrees include impaired wound healing and local infection. This study investigates the influence of preoperative, high-dose radiotherapy on subcutaneous accumulation of collagen in a primary rectal cancer group operated on with or without adjuvant radiotherapy. METHODS: Forty-two eligible patients who underwent total mesorectal excision surgery with or without radiotherapy were included in the study. Polytetrafluoroethylene tubings were implanted in the arm ten days before surgery (three days before the start of radiotherapy). Implants were extracted the day before surgery. New implants were inserted before surgery and were extracted ten days after surgery. The hydroxyproline and proline contents of the implants were measured and the hydroxyproline/proline ratio was calculated as a measure for deposited collagen relative to protein. Blood loss, postoperative complications, and blood levels of hemoglobin, leukocytes, and albumin were recorded. RESULTS: The two groups were similar in relation to Dukes stage, age, and body mass index. Infectious complications developed in 39 percent of patients after radiotherapy compared with 16 percent in the nonirradiated group. In the irradiated patients with infective complications we found a significant decrease in the hydroxyproline/proline ratio compared with that of irradiated patients without infections (P = 0.037). There was a significant decrease in the leukocyte count preoperatively and postoperatively in the irradiated group compared with surgery alone. CONCLUSIONS: High-dose, short-term radiotherapy does not have a systemic effect on collagen accumulation, but a significant reduction is manifested in infected patients. Radiotherapy also impairs leukocyte production and increases the postoperative infective complication rate.
Subject(s)
Collagen/radiation effects , Rectal Neoplasms/radiotherapy , Skin/radiation effects , Surgical Wound Infection/etiology , Aged , Blood Loss, Surgical , Collagen/metabolism , Female , Hemoglobins/analysis , Hemoglobins/radiation effects , Humans , Hydroxyproline/analysis , Hydroxyproline/radiation effects , Intubation/instrumentation , Leukocyte Count , Leukocytes/radiation effects , Male , Middle Aged , Polytetrafluoroethylene , Preoperative Care , Proline/analysis , Proline/radiation effects , Prospective Studies , Radiotherapy Dosage , Radiotherapy, Adjuvant/adverse effects , Rectal Neoplasms/surgery , Serum Albumin/analysis , Skin/metabolismABSTRACT
Studies of physical, chemical and biological variables of the pelagic community were performed during 1989 in Zaza, the largest freshwater reservoir in Cuba. The reservoir is warm-monomictic. The circulation period lasted from October to March and the water column stability was low, due to a large surface area and to a wind exposed location. Dissolved oxygen was usually below the saturation point, owing to a high load of organic matter. The low oxygen concentrations appear to have responsible for a low efficiency in the decomposition of organic matter and in denitrification. The inorganic fraction of nitrogen was always detectable in the upper circulating layer (0-12 m), whereas inorganic phosphorus was only detectable after June. Standing stock of phytoplankton was relatively low. Phytoplankton production was probably limited by light and phosphorus. Diatoms dominated during the mixing period and Cyanophyceae and Crytophyceae during stratification. For most part of the year biomass of Copepoda was higher than biomass of Cladocera and Rotatoria
