Cardiac compression by a thymic cyst.
A patient with a giant thymic cyst, causing cardiac compression, is presented. Thymic cysts are uncommon and often asymptomatic.
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Biomedical subjects
P Stas
Publications and source records attributed to P Stas.
Radiation-induced impairment of bone healing in the rat femur: effects of radiation dose, sequence and interval between surgery and irradiation.
BACKGROUND AND PURPOSE: Impairment of osseous healing in treatment combining surgery and radiotherapy is a frequent complication. Its dependence on sequence and interval was studied in a defined experimental model. MATERIALS AND METHODS: The effect of pre- and postoperative irradiation by single doses of X-rays on osseous closure of a 1.2 mm drill hole in the rat femur was measured 6 or 7 weeks after surgery in histological sections using morphometrical methods. RESULTS: Irradiation delivered between 1 day and 6 months before surgery resulted in a reduction of bone healing following very similar dose response relationships; there was no evidence of any slow repair of latent radiation damage. Radiosensitivity of bone healing during the first 3 days after surgery was not different from preoperative irradiation; however, irradiation 4 days or later after surgery failed to reduce osseous healing even after very high radiation doses. CONCLUSION: Tolerance increases enormously if radiotherapy is given later than 4 days after surgery. This has great implications for combined radiotherapy and surgery schedules involving bone reconstruction, but may be even more important for radiotherapy applied to prevent heterotopic ossification after total hip arthroplasty. Biologically, target cell regeneration alone is insufficient to account for the drastic rise in radiotolerance; it must be accompanied by an increase in cellular resistance due to differentiation.
Animals↗
Biological effectiveness of neutrons and pi-mesons in gut, bone, and transplantable tumours.
At the Munich RENT-facility a screening project was performed to define the biological characteristics of a fission neutron beam envisaged for radiotherapy. The quantitative endpoints used were jejunal crypt survival, late rectal stenosis in rats, osseous healing in traumatized rat femur and regrowth delay of murine transplantable tumours. The results obtained in normal tissues (with the possible exception of bone) demonstrate a high RBE, in accordance with the well documented dependence of RBE on neutron energy. The RBE-values measured in tumours after single dose treatment endorsed the high effectiveness, although--as has been the case with other beams--they gave no conclusive evidence of a therapeutic advantage. Nevertheless, the specific beam characteristics, i.e. a high RBE at the surface and a fast decline of the biologically effective depth dose suggest possible advantages of the RENT beam when applied in the treatment of selected superficial tumours.
Animals↗
Miliary tuberculosis following infliximab therapy for Crohn disease: A case report and review of the literature.
We present a case of miliary tuberculosis diagnosed 15 months after infliximab treatment despite negative screening for previous exposure to Mycobacteria on skin PPD and chest X-ray. This case shows that--although screening for TB with a skin PPD and a chest X-ray should be performed in all patients--this is not 100% effective and may be a problem in patients on concomitant immunosuppression. The clinical course of this patient further shows that in a patient treated with anti-TNF antibodies who's condition does not improve one should always be aware of the possibility of a tuberculosis infection. Even though tuberculosis is usually not rapidly fatal, the disease may show a fulminant course in immunocompromised patients.
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