A 2-year dose-response study of lesion sequences during hepatocellular carcinogenesis in the male B6C3F(1) mouse given the drinking water chemical dichloroacetic acid. (1/18)

Dichloroacetic acid (DCA) is carcinogenic to the B6C3F(1) mouse and the F344 rat. Given the carcinogenic potential of DCA in rodent liver and the known concentrations of this compound in drinking water, reliable biologically based models to reduce the uncertainty of risk assessment for human exposure to DCA are needed. Development of such models requires identification and quantification of premalignant hepatic lesions, identification of the doses at which these lesions occur, and determination of the likelihood that these lesions will progress to cancer. In this study we determined the dose response of histopathologic changes occurring in the livers of mice exposed to DCA (0.05-3.5 g/L) for 26-100 weeks. Lesions were classified as foci of cellular alteration smaller than one liver lobule (altered hepatic foci; AHF), foci of cellular alteration larger than one liver lobule (large foci of cellular alteration; LFCA), adenomas (ADs), or carcinomas (CAs). Histopathologic analysis of 598 premalignant lesions revealed that (a)) each lesion class had a predominant phenotype; (b)) AHF, LFCA, and AD demonstrated neoplastic progression with time; and (c)) independent of DCA dose and length of exposure effects, some toxic/adaptive changes in non-involved liver were related to this neoplastic progression. A lesion sequence for carcinogenesis in male B6C3F(1) mouse liver has been proposed that will enable development of a biologically based mathematical model for DCA. Because all classes of premalignant lesions and CAs were found at both lower and higher doses, these data are consistent with the conclusion that nongenotoxic mechanisms, such as negative selection, are relevant to DCA carcinogenesis at lower doses where DCA genotoxicity has not been observed.  (+info)

Effect of long-term treatment with somatostatin analogue (SMS 201-995) on pituitary tumor shrinkage in acromegaly--report of two cases. (2/18)

The effect of long-term somatostatin analogue (SMS 201-995) treatment in two acromegalic patients is reported. Continuous tumor shrinkage was observed even after 129 and 139 weeks of treatment with 600 micrograms of SMS 201-995 daily. A huge and firm adenoma underwent shrinkage during treatment with SMS 201-995. No serious side effect appeared during 160 weeks of treatment. SMS 201-995 has a longterm tumor shrinkage effect and improves endocrinopathies.  (+info)

Ectopic growth hormone-releasing adenoma in the cavernous sinus--case report. (3/18)

A 55-year-old woman presented a rare ectopic pituitary adenoma in the right cavernous sinus manifesting as acromegaly. The tumor was removed via transsphenoidal approach. Intraoperative observation showed the adenoma was located entirely within the right cavernous sinus, and separated from the normal pituitary gland by the medial wall of the cavernous sinus. There was no communication between the tumor and the pituitary. Histological examination showed a growth hormone-releasing adenoma. Including our case, only eight of 86 reported ectopic adenomas have occurred in the cavernous sinus. Such ectopic presentation may be responsible for failed transsphenoidal surgery for endocrinologically active tumors.  (+info)

Characterization of human pituitary adenomas in cell cultures by light and electron microscopic morphology and immunolabeling. (4/18)

The morphology and hormone production of pituitary adenoma cell cultures were compared in order to highlight their characteristic in vitro features. Cell suspensions were prepared from 494 surgical specimens. The 319 viable monolayer cultures were analyzed in detail by light microscopy and immunocytochemistry within two weeks of cultivation. Some cultures were further characterized by scanning, transmission and immunogold electron microscopy. The viability and detailed in vitro morphology of adenoma cells were found to be characteristic for the various types of pituitary tumors. The sparsely granulated growth hormone, the corticotroph and the acidophil stem cell adenomas provided the highest ratio of viable cultures. Occasionally, prolonged maintenance of cells resulted in long-term cultures. Furthermore, a variety of particular distributions of different hormone-containing granules were found in several cases. Both light microscopic and ultrastructural analyses proved that the primary cultures of adenoma cells retain their physiological features during in vitro cultivations. Our in vitro findings correlated with the routine histopathological examination. These results prove that monolayer cultures of pituitary adenoma cells can contribute to the correct diagnosis and are valid model systems for various oncological and neuroendocrinological studies.  (+info)

Familial pituitary adenoma--report of four cases from two unrelated families. (5/18)

The authors report four cases of familial pituitary adenomas from two unrelated families. No clinical or biochemical evidence of multiple endocrine neoplasia, type I (MEN-I) was demonstrated. Detailed study of the family trees disclosed no other family members affected by MEN-I. Familial occurrence of pituitary adenomas unassociated with MEN-I is rare.  (+info)

Pituitary acidophil macroadenoma in a pygmy goat (Capra hircus hircus). (6/18)

This report describes a pituitary acidophil macroadenoma in a goat. Antemortem clinical findings included hypothermia and rumen stasis. Clinicopathologic findings included refractory hypoglycemia, low total thyroxin and insulin concentrations, elevated bile acid concentration, and hyposthenuria. In addition to the pituitary macroadenoma, bilateral atrophy of the zona reticularis of the adrenal glands was observed histologically.  (+info)

A new look at pituitary adenomas: structure elucidating function. (7/18)

Cases of seven different types of surgically resected pituitary adenoma are described. Included are tumours secreting prolactin or growth hormone or both, and nonfunctioning tumours--undifferentiated and oncocytic tumours, and one tumour with cells of the adrenocorticotropin-melanocyte-stimulating hormone type. The final interpretation of a case of pituitary adenoma should include an assessment of thorough morphologic studies, using not only routine staining and light microscopy but also immunostaining and electron microscopy, to complement the biochemical, radiologic and clinical evaluation.  (+info)

Transcranial management of pituitary tumours with suprasellar extension. (8/18)

A consecutive series of 101 pituitary tumours treated in the 10 year period 1968-78 has been examined, giant lesions being excluded. There were 48 female cases and 53 male, women predominating in the ratio of three to two in the age group 40-50 years and men showing a slight predominance in the age group 50-60 years. Most cases presented with visual deterioration which in 22 cases had been present for between one and two years, and in a further 22 for an even longer period, between two and 10 years. All patients underwent subfrontal craniotomy with mainly radical excision of the tumour followed by radiotherapy. The operative mortality was 0.99%. A system of grading of visual field defect has been described and used to compare preoperatively visual loss with postoperative visual recovery. Fifty-six per cent of cases returned to normal vision over the first two years, and a further 37% showed appreciable improvement in visual fields or acuity or both. Six per cent of cases showed no improvement in visual fields, and one patient died of postoperative deep vein thrombosis and pulmonary embolism. The degree of visual improvement has been correlated with the extent of visual defect, length of visual complaint, and size of the tumour. The importance of central and peripheral visual field analysis is emphasised yet again.  (+info)

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