Qualitative and quantitative effects on the morphology of the small intestine after multiple daily fractionation

Marker Determination for Response Monitoring: Radiotherapy and Disappearance Curves

This paper reports the results of studies on the possible role of biochemical markers in monitoring the effects of ionizing radiations and in the follow-up of cancer patients submitted to radiotherapy.

Three different case series were analyzed: patients with head and neck cancer, prostate carcinoma and residual thyroid tumors or uptaking metastases (131-Iodine therapy).

Serum TPA and amylase were serially determined in patients with head and neck or thyroid cancer to measure the radiation damage to the salivary glands. In the former group a statistically significant correlation between the increase of both molecules and the total dose administered after the first day of treatment (2, 3, 4 or 6 Gy) was observed. In patients treated for thyroid cancer the damage to the salivary glands was revealed by an increase in TPA and amylase serum levels, dependent on the dose of 131-Iodine administered. Moreover, an association was demonstrated between pretreatment values of TPA in patients with head and neck tumors and prognosis: patients with values below the cutoff have significantly higher survival rates than those with higher values.

In patients with prostate carcinoma PSA was confirmed to have better diagnostic and prognostic value than PAP. Patients with metastases show an inversion or lack of negative trend in PSA levels observed in the disease-free patients. This precedes the clinical diagnosis of metastases by 1 to 15 months.

Effects of radiation damage on intestinal morphology

The current flow of papers on intestinal structure, radiation science, and intestinal radiation response is reflected in the contents of this review. Multiparameter findings and changes in compartments, cells, or subcellular structure all contribute to the overall profile of the response. The well-recognized changes in proliferation, vessels, and fibrogenesis are accompanied by alterations in other compartments, such as neuroendocrine or immune components of the intestinal wall. The responses at the molecular level, such as in levels of hormones, cytokines, or neurotransmitters, are of fundamental importance. The intestine responds to localized radiation, or to changes in other organs that influence its structure or function: some structural parameters respond differently to different radiation schedules. Apart from radiation conditions, factors affecting the outcome include the pathophysiology of the irradiated subject and accompanying treatment or intervention. More progress in understanding the overall responses is expected in the next few years.

Cell proliferation and differentiation in the small intestine after irradiation with multiple fractions

Qualitative and quantitative morphologic changes in rat small intestine were studied after abdominal exposure to multiple fractions of gamma radiation. One group of animals received 3 X 2 Gy with one fraction every 4 hours. Another group received two courses of this type with a 16 hour interval between the courses (total dose 6 X 2 Gy). A marked decrease in the number of crypt epithelial cells, and in mitotic and labelling indices, was observed up to 24 to 36 hours after the end of both regimens. Repair and recovery occurred within 72 hours after the end of the last exposure, and the epithelium regained normal morphology. At 1 and 4 hours after the end of the treatment the frequency of S-phase cells along the crypt was greatly reduced and at the following intervals labelled cells occupied the region where differentiation occurs in control animals. During recovery labelled cell distribution showed a gradual return to normal. No substantial differences between the effects of total doses of 6 and 12 Gy were shown except for a greater reduction in crypt epithelial cells at the early time intervals after the larger dose.

Quantitative changes in the goblet cells of the rat small intestine after irradiation

In order to evaluate the process of cell differentiation in the crypt of the rat small intestine the goblet cells were quantitatively studied in controls and after irradiation of the abdomen. The effect of a single dose, administered at 4 different times of the day, and multiple daily fractionations (MDF) of 6 and 12 Gy with different doses per fraction and different time intervals, were compared. Both regimens caused an initial increase of the goblet cells (both in absolute and relative terms), followed by a decrease and finally return to nearly control levels. After MDF the increase was more marked and the return to a normal level occurred earlier than after the single dose.