Radiation response of mouse lip mucosal epithelium: a cell kinetic study.

Changes in the cell proliferation kinetics of the epithelium of mouse lip mucosa have been assessed after local irradiation with a single dose of 18 Gy of 60Co gamma-rays. By the fifth day after irradiation, two distinct sub-populations of epithelial cells could be discerned. The larger of the two populations consisted of cells exhibiting varying degrees of radiation-induced damage, and the smaller population was composed of cells of normal size and appearance, intermingled between the radiation-damaged cells.

Sensitivity of human squamous cell carcinoma of the larynx to fractionated radiotherapy.

Data obtained for the response of tumours from two multicentre clinical trials of the British Institute of Radiology have been combined and studied. Both trials involved patients with laryngopharyngeal carcinoma. There were 734 patients in the first trial, recruited between 1965 and 1975, and 611 patients in the second trial, recruited between 1975 and 1985.

Dose- and source-size-related changes in the late response of pig skin to irradiation with single doses of beta radiation from sources of differing energy.

Late radiation damage to pig skin has been assessed at 104 weeks after exposure to sources of 90Sr/90Y (Emax 2.2 MeV) and 170Tm (Emax 0.9 MeV).

Modification of late dermal necrosis in the pig by treatment with multi-wavelength light.

Low-level light from a multi-wavelength light source has been used to prevent late X-ray-induced dermal necrosis in the pig. Skin fields, measuring 4 cm x 4 cm on the flank, were irradiated with graded doses of X rays and the incidence of late dermal necrosis at 10-16 weeks after irradiation was scored. The control skin sites were irradiated only with 250 kV X rays but the test skin sites were subsequently exposed to low-level light.

Functional changes in the pig kidney following irradiation with fractionated doses of fast neutrons (42 MeVd-->Be).

The right kidney of female Large White pigs, approximately 14 weeks old, was irradiated with fractionated doses of fast neutrons (42 MeVd-->Be). The total doses used were 6.6-9.

The influence of methotrexate on radiation-induced damage to different lengths of the rat spinal cord.

An experimental model in the rat has been used to assess the possible enhancement of damage to the spinal cord when radiation is given in the presence of methotrexate (MTX). The dose of MTX used, 4 mg/kg, was the maximum dose that could be given to the rat, when administered into the cerebral spinal fluid circulation, without risk of serious neurological effects. Lengths of 4, 8 and 16 mm of the cervical spine were irradiated with single doses of X rays.

Reduction in the diameter of human hairs following irradiation.

A measurable reduction in hair diameter was observed in human hairs following single exposures to gamma-rays, 250 KeV X-rays, 8 MV photons and 10 MV electrons in the range 2.9-14.0 Gy.

Long-term studies of cisplatin-induced reductions in porcine renal functional reserve.

Mature Large White female pigs aged approx. 10 months received single intravenous doses of 1.5, 2, or 2.

Prevention of X-ray-induced late dermal necrosis in the pig by treatment with multi-wavelength light.

Low-level light from a multi-wavelength array of light sources has been used to prevent late X-ray-induced dermal necrosis in the pig. Skin fields, measuring 4 x 4 cm on the flank, were irradiated with a single dose of 23.4 Gy of X-rays.

Studies of dose-fractionation on early and late responses in pig skin: a reappraisal of the importance of the overall treatment time and its effects on radiosensitization and incomplete repair.

Studies in pig skin have examined the effects of dose fractionation on the acute radiation response. The variation in ED50 values for moist desquamation for doses given as 1-48 fractions over less than or equal to 16 days were best fitted by a log-log plot of iso-effect dose against the number of fractions; the slope of this plot indicated a fraction number exponent (N) of 0.42 +/- 0.

The relative biological effectiveness of fractionated doses of fast neutrons (42 MeVd----Be) for normal tissues in the pig. IV. Effects on renal function.

The effects of fractionated doses of fast neutrons (42 MeVd----Be) on the radiation response of the pig kidney have been assessed and compared with those observed after X irradiation. Following X irradiation there was a marked increase in the total dose at which renal function was preserved with decreasing fraction size. The rate of this increase was dependent on the overall treatment time; for fractionated irradiation given over 18 or 39 days the exponents related to fraction number, N, were 0.

A morphological study of radiation nephropathy in the pig.

Both kidneys of mature pigs received a single dose of 9.8 Gy 60Co gamma rays. Pigs were killed between 2 and 24 weeks after irradiation and the kidneys examined histologically.

The effect of unilateral nephrectomy on the subsequent radiation response of the pig kidney.

The left kidney of 14 Large White female pigs, approximately 14 weeks of age, was surgically removed. Thirty weeks after unilateral nephrectomy (UN) the remaining kidney was irradiated with a single dose of between 11.9 and 15.

Protection of pig epidermis against radiation-induced damage by the infusion of BW12C.

BW12C, which was developed as an agent for the treatment of sickle cell anaemia, increases the binding of oxygen to haemoglobin and hence reduces the availability of oxygen to tissues. Due to these changes in oxygen availability BW12C could act as a protector against radiation-induced injury to normal tissues. In this study the potential value of BW12C, as a radioprotector, was studied in the irradiated epidermis of the pig.

Reduced cardiotoxicity of doxorubicin given in the form of N-(2-hydroxypropyl)methacrylamide conjugates: and experimental study in the rat.

A rat model was used to evaluate the general acute toxicity and the late cardiotoxicity of 4 mg/kg doxorubicin (DOX) given either as free drug or in the form of three N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer conjugates. In these HPMA copolymers, DOX was covalently bound via peptide linkages that were either non-biodegradable (Gly-Gly) or degradable by lysosomal proteinases (Gly-Phe-Leu-Gly). In addition, one biodegradable conjugate containing galactosamine was used; this residue was targeted to the liver.

Direct analysis of quantitative data from radiobiological studies on pig lung.

An alternative approach for the analysis of quantitative data, obtained from functional measurements, has been developed. The method does not require conversion of the quantitative measurements into quantal data thus defining a threshold level of effect. This method describes a parameter, equivalent to an iso-effective dose, which can be used for the comparison of different fractionation schedules by the assessment of lung function in radiobiological studies.

The predictive value of tumor classification compared with results of the British Institute of Radiology fractionation trial in the treatment of laryngopharyngeal carcinoma.

Data from a clinical trial involving 734 patients have shown the value and the deficiencies of the current Union Internationale Contre le Cancer's tumor, node, and metastasis classification system for prognostic purposes. The tumor-category classification provides a good discriminant for both nodal involvement and survival; however, the previous node classification system only discriminated between node-negative and node-positive patients, as nodal fixity was not found to be a discriminator. The current anatomical site classification is ambiguous for some laryngeal and pharyngeal subsites, and modifications to the present system based on prognostic values are proposed.

Epidermal cell kinetics of the pig: a review.

Age-related changes in cell kinetic parameters for the epidermis of pigs have been shown to be small, indicating that young pigs may be used for experimental studies. It was not possible to draw any firm conclusions about any strain-related differences in the cell kinetics of the epidermis of the pig. Lower LI values have been quoted for the miniature pig and the Yorkshire pig than for the Large White pig.

The skin: its structure and response to ionizing radiation.

The response of the skin to ionizing radiation has important implications both for the treatment of malignant disease by radiation and for radiological protection. The structural organization of human skin is described and compared with that of the pig, with which it shows many similarities, in order that the response of the skin to ionizing radiation may be more fully understood. Acute radiation damage to the skin is primarily a consequence of changes in the epidermis; the timing of the peak of the reaction is related to the kinetic organization of this layer.

Age-related changes in the cell kinetics of rat foot epidermis.

The durations of the cell cycle and its component phases have been determined for the basal layer of the epidermis of the skin from the upper surface of the hind foot of the rat using single pulse [3H]-thymidine labelling and the percent labelled mitosis (PLM) technique. Rats of three age groups were used, namely 7, 14 and 52 weeks. The duration of DNA synthesis (Ts) and the G2 plus M phase (TG2 + M) were comparable in 7-week and 52-week-old rats (P greater than 0.

The response of the pig lung to fractionated doses of X rays.

A radionuclide 133Xe clearance technique has been used to assess changes in the regional gas exchange capacity of the lung after the irradiation of part of the lung of pigs with fractionated doses 250 kV X rays. Changes in the gas-exchange capacity of an irradiated volume of lung were compared with a similar volume of unirradiated lung in each animal. The results from the lung function tests were converted into quantal data on the basis of the percentage of lung function tests in animals showing a greater than or equal to 15% impairment of function in the irradiated lung compared with contralateral unirradiated lung in the same animal.

Cisplatin-induced reductions in renal functional reserve uncovered by unilateral nephrectomy: an experimental study in the pig.

Groups of mature Large White female pigs, approximately 10 months of age, received single intravenous infusions of 1.5, 2 or 2.5 mg/kg body weight (equivalent to approximately 90, approximately 120 and approximately 150 mg/m2) cisplatin.

The effects of single doses of X rays on the mechanical properties of pig skin in vivo.

Changes in the mechanical properties of pig skin have been studied in vivo, using a dermal extensometer, after irradiation with a single dose of 18 Gy of X rays. There was no significant change in the stiffness of irradiated skin, when compared with unirradiated skin, until 9 weeks after irradiation when the irradiated skin was significantly stiffer. This effect was also found at 12 and 15 weeks after irradiation.

The effect of age and the proportion of renal tissue irradiated on the apparent radiosensitivity of the pig kidney.

In 14-week-old (immature) and 45-week-old (mature) pigs either the right kidney (unilateral irradiation, UI) or both kidneys (bilateral irradiation, BI) were irradiated. The kidneys of immature pigs received single doses of 7.0-12.