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At least 343 records · Page 19Linked to original sources
PubMed1976

Effects of grafts of single anterior pituitary glands on the incidence and type of mammary neoplasm in neutron- or gamma-irradiated Fischer female rats.

Three batches comprised of 48 young adult Fischer female rats each were subjected to total-body irradiation with 50 rads modified fission neutrons, or were given 600 rads 137Cs gamma-rays, or served as unirradiated controls. On the day following exposure, one-half of each batch was grafted with a single anterior pituitary gland beneath the left kidney capsule. The animals were observed for mammary neoplasia and all those that died during the experiment were autopsied. The experiment was terminated 538 +/- 13 days after irradiation when all neutron-irradiated, pituitary-grafted animals had one or more mammary tumors. Only 2 of the 23 untreated rats that survived until termination of the experiment developed mammary fibroadenomas, and none had mammary carcinomas. The incidence of fibroadenomas was increased, and a single carcinoma was found, in unirradiated rats with pituitary grafts. Irradiation alone caused an increase in the incidence of mammary fibroadenomas and the appearance of carcinomas. Fibroadenomas were markedly increased by the addition of pituitary grafts to irradiation. Carcinoma incidence was less markedly affected. The neutron dose of 50 rads was slightly more effective in inducing mammary neoplasms than the 600-rad dose of gamma-rays.

Adenofibroma↗
PubMed1997

[Late effects of ionizing radiations on the thyroid gland].

The thyroid is the purest endocrine gland in the body and is likely to produce clinically significant abnormalities after external radiotherapy. Functional clinical modifications after direct irradiation exceeding 30 Gy are essentially related to hypothyroidism which may be clinically overt or subclinical with normal serum free thyroxine levels and high thyrotropin concentrations; the risk of hyperthyroidism, silent thyroiditis and Hashimoto's disease is also increased. Secondary hypothyroidism related to irradiation of the hypothalamus and the pituitary gland may arise with doses over 40-50 Gy following treatment for brain and nasopharyngeal tumors--Morphological glandular modifications induced by radiotherapy are responsible for the appearance of benign adenomas, more rarely cystic degenerations and specially well differentiated papillary or follicular carcinomas among children and adults. After irradiation during childhood for benign or malignant tumors, thyroid cancers are more frequent, higher for younger children, and the relative excess risk is increased from 15.6-to 53-fold; tumors can belatedly occur, more than 35 years after initial therapy. Thereby, in order to limit excess morbidity, it is evident that long term supervision with careful clinical and biological evaluations is necessary for patients who previously received neck, upper mediastinum and pituitary radiation therapy.

Adult↗
PubMed1997

A comparison between microwave irradiation and decapitation: basal levels of dynorphin and enkephalin and the effect of chronic morphine treatment on dynorphin peptides.

Opioid peptides were analysed in tissue extracts of various brain structures and the pituitary gland from rats sacrificed by microwave irradiation, and compared with peptide levels in tissue extracts from decapitated rats. Dynorphin A, dynorphin B and Leu-enkephalinArg6, derived from prodynorphin, and Met-enkephalinArg6Phe7 from proenkephalin, were measured. Basal immunoreactive levels of dynorphin A and B were consistently higher in extracts from microwave-irradiated rats, whereas in these extracts immunoreactive levels of Leu-enkephalinArg6, an endogenous metabolite of dynorphin peptides, were either lower than, the same as or higher than in decapitated rats. Immunoreactive levels of Met-enkephalinArg6Phe7 were higher in microwave-irradiated rats. Effects of morphine treatment on prodynorphin peptide levels were evaluated and compared with previous findings in decapitated rats. Dynorphin immunoreactive levels were higher in the nucleus accumbens and striatum of morphine-tolerant rats than in corresponding areas in saline-treated rats. These results indicate tissue-specific metabolism of prodynorphin peptides and show that metabolism of opioid peptides occurs during the dissection procedure after decapitation of the rat even though precautions are taken to minimize degradation.

Animals↗
PubMed1996

[Radiation dose in critical organs due to non-coplanar irradiation of the hypophysis].

BACKGROUND: In order to estimate the somatic and genetic risk associated with a non-coplanar linac-based radiation technique of the pituitary gland, systematic secondary-dose measurements in a phantom and sample measurements of the dose near critical organs of patients were performed. PATIENTS AND METHODS: For measurements of the dose outside the primary radiation field an acrylic-PVC phantom was used which was irradiated with a single field (4 x 4 cm2). Eight patients with pituitary tumors were treated isocentrically with a combination of sagittal and transverse rotational arcs. To measure the dose in critical organs. LiF thermoluminescence dosimeters (TLD) in chip form were placed onto 1 eyelid, the skin over the thyroid, and the patient's clothes covering the region of breasts and ovaries of female patients and the testicles of male patients. Measurements were performed for all patients during 1 sagittal irradiation and for the majority of patients during 1 transverse irradiation. RESULTS: The phantom measurements demonstrated that the secondary dose measured on the patients surface can be considered as a good approximation for the dose in adjacent organs. The median dose in critical organs for sagittal irradiation was in the range of 25.8 mGy (eyes) to 1.9 mGy (testicles), and for transverse irradiation in the range of 23.3 mGy (eyes) to 1.3 mGy (testicles). The ratio of median organ doses for sagittal and transverse irradiation was 2.1 for the thyroid gland, 1.1 for the eyes, and 1.5 for the other organs. CONCLUSIONS: The dose in critical organs due to non-coplanar irradiation of the pituitary gland is only a small fraction of the dose delivered to the reference point of the planning target volume. The risk of a radiation-induced tumor and a genetic consequence associated with these small doses is generally less than 1% and 0.1%, respectively.

Adenoma↗
PubMed2000

Fractionated, three-dimensional, planning-assisted proton-radiation therapy for orbital rhabdomyosarcoma: a novel technique.

PURPOSE: Most children with orbital rhabdomyosarcoma will survive their disease. However, conventional photon-radiation treatment, as part of multimodality therapy, results in varying degrees of long-term functional and cosmetic side effects. This report introduces external beam proton radiation therapy (PRT) as a conformal, three-dimensional planned radiation technique for this disease, analyzes normal tissue dosimetry, and describes the technique's application in the first 2 patients. MATERIAL AND METHODS: Between January 1995 and February 1996, 2 patients underwent PRT following biopsy and chemotherapy for orbital rhabdomyosarcoma. Fifty and 55 Cobalt Gray Equivalent (CGE) were delivered to the gross tumor volume and 40 CGE to clinical target volumes in both patients. A relative biologic effectiveness (RBE) of 1.1 was utilized to correlate proton dose calculations with CGE. To achieve dose conformity, a "patch technique" was utilized, where target regions were divided into segments, each treated by a separate proton field. Dose-volume histograms were obtained for target and nontarget regions, including lens, bony orbit, pituitary gland, optic chiasm, optic nerves, lacrimal gland, and ipsilateral frontal and temporal lobes. RESULTS: At 3.4 and 2.5 years after PRT, both patients are clinically and radiographically free of disease. Visual acuity remains excellent, without signs of cataract formation; pituitary function is normal; cosmetically, only mild enophthalmos is noticeable. Doses to 90%, 50%, and 5% of lens volume were kept at less than 1%, less than 2%, and less than 8%, respectively. Fifty percent of lacrimal gland volume received less than 36% of the prescribed dose and 50% of the volume of the optic chiasm, pituitary gland, and hypothalamus were restricted to less than 2%. Proton conformity to orbital contents resulted in between 9% and 36% of the prescribed dose reaching the ipsilateral temporal and frontal lobes immediately adjacent to bony orbit (5% volume). CONCLUSION: PRT can offer excellent sparing of lens and selected intraorbital and ocular normal structures, while maintaining conformal target-dose coverage. The steep dose gradient beyond the orbit minimizes irradiation of normal brain parenchyma, with almost complete sparing of the pituitary gland. Reduction of integral irradiation exposure of the periorbital region will, hopefully, reduce the risk of second malignancy later in life. Reduced radiation dose to specific organs in close proximity to, but not part of the target region promises improved functional outcome and better cosmesis for childhood cancer survivors.

Child↗
PubMed1992

Carcinogenic effect of in utero 252Cf and 60Co irradiation in C57BL/6N x C3H/He F1 (B6C3F1) mice.

C57BL/6N x C3H/He F1 mice were exposed in utero to 0, 1.0 and 2.7 Gy of 252Cf or 60Co at day 16.5th of gestation. Mice of both sexes were observed for 2 years. The females in the irradiated groups showed increases in the incidences of pituitary, mammary gland, liver and lung tumors. 252Cf was more effective in inducing tumors than was 60Co. Interestingly, the incidence of hematopoietic tumors decreased by irradiations with 252Cf but not with 60Co. The incidences of liver tumors in males increased by 252Cf-irradiation, whereas, the incidences of skin and soft tissue tumors increased by 60Co-irradiation. These results indicate that irradiation in utero during the late embryonic stage can induce tumors postnatally after a long latency. Moreover, females irradiated in utero had disfunction of the ovaries, evidence of impairment of the female's specific hormonal environment. This may be the cause of the low incidence of ovarian tumors and the high incidences of liver, lung and pituitary tumors in these female mice. Females with pituitary tumors had a high serum prolactin, which might be responsible for the concurrence of mammary gland tumors. These results indicate the importance of host factors in the development of radiation-induced tumors.

Animals↗
PubMed1997

The long-term outcome of pituitary irradiation after unsuccessful transsphenoidal surgery in Cushing's disease.

BACKGROUND: Irradiation of the pituitary is widely considered the most appropriate treatment for patients with Cushing's disease in whom transsphenoidal microsurgery has been unsuccessful. However, there is little information about the long-term efficacy of this treatment. METHODS: We used external pituitary radiation to treat 30 adult patients with persistent or recurrent Cushing's disease after unsuccessful transsphenoidal surgery. The mean (+/-SD) dose of radiation was 50+/-1 Gy. Pituitary and adrenal function was assessed every six months after radiation therapy. Remission was defined as the regression of symptoms and signs of Cushing's syndrome, normal urinary cortisol excretion, and a low plasma cortisol concentration in the morning after the administration of 1 mg of dexamethasone at midnight. RESULTS: Twenty-five patients (83 percent) had remissions during a median follow-up of 42 months (range, 18 to 114). The remissions began 6 to 60 months after radiation therapy, but in most cases (22 patients) remission occurred during the first 2 years. None of the 25 patients had a relapse of Cushing's disease after remission was achieved. There was no relation between the response to radiotherapy and sex, age, urinary cortisol excretion before radiotherapy, the interval between surgery and radiotherapy, whether a pituitary adenoma was found by pathological examination, or tumor size. Seventeen patients had a deficiency of growth hormone after radiation therapy, 10 had a deficiency of gonadotropins, 4 had a deficiency of thyrotropin, and 1 had a deficiency of corticotropin. CONCLUSIONS: Pituitary irradiation is an effective and well-tolerated treatment for patients with Cushing's disease in whom transsphenoidal surgery is unsuccessful.

Adolescent↗
PubMed1990

[Hypofunction of peripheral target-gland after radiotherapy of pituitary adenoma--an analysis of 140 cases].

One hundred and forty cases of pituitary adenoma, treated by surgery plus radiotherapy or radiotherapy alone from 1978 to 1985, were analysed as to the incidence of hypothalamo-pituitary and peripheral target-gland hypofunction after radiotherapy. The incidence of hypothyroidism, hypogonadism and hypoadrenalism was 51.7%, 61.4% and 17.8%, respectively. Thyroid and gonad were vulnerable following hypothalamo-pituitary hypofunction, and the incidence was 19.2% and 23.5% individually, and 27.1% simultaneously. The incidence of hypoadrenalism was 7.1%. The total incidence of target-gland hypofunction was 10.7%. Hypofunction of the posterior lobe of the pituitary often occurred after operation. For patients treated with radiotherapy alone, the incidence of hypothalamo-pituitary and target-gland hypofunction was high because of higher irradiation dose. Hormonotherapy was successful in the treatment of hypopituitarism and target-gland hypofunction. For radiotherapy of pituitary adenoma, DT 40-45 Gy and treatment field 4 x 4 cm are recommended.

Adenoma↗
PubMed1978

Pituitary fibrosarcoma secondary to radiation therapy.

A patient who received postoperative radiation therapy for the treatment of a chromophobe adenoma developed a fibrosarcoma of the pituitary gland region 10 years later. A single course of irradiation was given with a total dose to the pituitary of 4092 rad in 21 fractions and 29 days using Cobalt 60 radiation at a source to skin distance of 80 cm.

Adenoma, Chromophobe↗
PubMed1989

Effect of cranial irradiation on hypothalamus and pituitary functions.

Hypopituitarism can occur after cranial irradiation for tumors distant from the pituitary gland. Recent studies have suggested that this is hypothalamic in origin. Hypothalamic and pituitary functions were studied in 11 patients, 4 men and 7 women, 4.5 years or more after radiotherapy for nasopharyngeal carcinomas. The estimated average total dose was 5000 cGys for the hypothalamus and pituitary gland. Except for 2 women with amenorrhea and 4 men with impotency, the patients did not have evident endocrine deficiency. Baseline hormone profiles revealed normal T4, T3 and cortisol levels, 6 with elevated prolactin, 3 with reduced testosterone and 3 with slightly elevated basal TSH. The four menopausal women had impaired gonadotropin response to LHRH (100 micrograms, i.v.). Four (1 menstruating, 1 amenorrheic, 2 menopausal) women did not reach peak FSH response 4 hours after LHRH injection. The other amenorrheic woman had minimal FSH and LH response to LHRH which persisted even after 8 days of pulsatile infusion of LHRH (1 microgram/90min). TSH response to TRH (400 micrograms, i.v.) was delayed in 7 patients. GH response to human GRH (1 microgram/kg, i.v.) was impaired in 6 patients (maximal GH less than 5 mU/l). ACTH response to ovine CRH (1 microgram/kg, i.v.) was impaired in 3 patients (less than 50% elevation from baseline). Three patients who had normal GRH tests had impaired GH response to insulin hypoglycemia. Six patients had an empty sella on CT scan. From this study the following conclusions are drawn: (1) Among the four axes, GH is the most vulnerable. (2) The insulin tolerance test is still the best single test for evaluation of hypothalamic function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

Development of a metastatic brain tumor model in mice.

This study reports an easily accomplished and reliable model of metastatic tumor in the brains of mice. Five experimental groups of female C3H/Bi mice received left intracardiac injections of a syngeneic KHT sarcoma cell suspension (1 X 10(5) cells) and were followed until death. Two groups of mice also received 3,000 rads of radiation to a limited cardiac port 24 hr after tumor injections. All mice were completely autopsied, and the brains were examined both grossly and microscopically. Metastatic brain tumor developed in 60 to 70% of mice; the tumor foci were parenchymal, usually multifocal, and had wide distribution throughout the cerebrum, brainstem, and cerebellum. There was occasional meningeal tumor, but tumor never involved the skull, choroid plexus, pituitary gland, or local extracranial structures. Cardiac irradiation did not increase the number of the mean survival of mice with metastatic brain tumor but did decrease the total tumor burden of individual animals by markedly reducing the incidence of metastatic lung tumor and totally preventing tumor infiltration of the heart. This demonstration of consistently produced blood-borne metastatic brain tumor in mice should provide a valuable research model which will allow the central nervous system to be studied for internal mechanisms and/or external factors which influence the arrest and growth of embolic tumor cells in the brain.

Animals↗