Efficacy of doxorubicin thermosensitive liposomes (40 degrees C) and local hyperthermia on rat rhabdomyosarcoma.

The efficacy of novel thermosensitive liposomes (40 degrees C) containing doxorubicin (Dox-Lip) together with local hyperthermia (HT) was studied on solid growing rat rhabdomyosarcomas. Tumor response and systemic toxicity were evaluated by comparing to free doxorubicin (Free Dox) with or without hyperthermia. Tumors were heated with infrared-A-radiation and drugs were infused intravenously after preheating the tumors followed by a further 60 min of heating at 42.

Zone-specific remodeling of tumor blood vessels affects tumor growth.

Background: Chaotic organization, abnormal leakiness, and structural instability are characteristics of tumor vessels. However, morphologic events of vascular remodeling in relation to tumor growth are not sufficiently studied yet.

Methods: By using the rat rhabdomyosarcoma tumor model vascular morphogenesis was studied by light and electron microscopy and immunohistochemistry in relation to tumor regions such as tumor surrounding (TSZ), marginal (TMZ), intermediate (TIZ), and center (TCZ) zones.

Oxygenation of tumor recurrences following fractionated radiotherapy of primary tumors. Studies on the rhabdomyosarcoma R1H of the rat.

Background And Purpose: Tumor oxygenation is well recognized as a major factor of tumor response to radiotherapy. In this respect, a number of studies have examined the response of primary tumors, whereas little is known about the oxygenation of tumor recurrences after radiotherapy. It was the aim of this study to investigate the oxygenation of tumor recurrences after preceding irradiation of the primary tumor.

Pentoxifylline enhances tumor oxygenation and radiosensitivity in rat rhabdomyosarcomas during continuous hyperfractionated irradiation.

Purpose: To examine the influence of the hemorrheologic agent pentoxifylline (PTX) on tumor oxygenation and radiosensitivity.

Material And Methods: Tumor oxygenation in rat rhabdomyosarcomas R1H after PTX administration (50 mg/kg body weight) was measured using interstitial pO(2) probes (Licox CMP system and Eppendorf pO(2)-Histograph). Tumors were irradiated with (60)Co gamma-irradiation using single doses (15 and 30 Gy), conventional fractionation (60 Gy/30 fractions/6 weeks), and continuous hyperfractionation (54 Gy/36 fractions/18 days) in combination with PTX or an equivalent volume of physiological saline.

The radioprotectors amifostine and sodium selenite do not modify the radiosensitivity of rat rhabdomyosarcomas.

Background: Radiotherapy of head and neck tumors often leads to acute reactions of the adjacent normal tissues resulting e.g. in mucositis and xerostomia.