PubMed · 8613829
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A M Landolt. 1996. Delayed hyponatremia.. https://doi.org/10.3171/jns.1996.84.1.0150b
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The high mobility group As (HMGAs) belong to a family of nonhistone nuclear proteins that orchestrate the assembly of nucleoprotein complexes. Through a complex network of protein-DNA and protein-protein interaction, they play important roles in gene transcription, recombination, and chromatin structure. This protein family is involved, through different mechanisms, in both benign and malignant neoplasias. We have recently reported that transgenic mice carrying the Hmga1 or Hmga2 genes under transcriptional control of the cytomegalovirus promoter develop pituitary adenomas secreting prolactin and growth hormone. We have shown that the mechanism of the HMGA2-induced pituitary adenoma is based on the increased E2F1 activity. The expression profile of mouse normal pituitary glands and adenomas induced in HMGA transgenic mice revealed an increased expression of the ccnb2 gene, coding for the cyclin B2 protein, in the neoplastic tissues compared with the normal pituitary gland. Here, we show, by electrophoretic mobility shift assay and chromatin immunoprecipitation, a direct binding of HMGA proteins to the promoter of ccnb2 gene, whereas luciferase assays showed that HMGAs are able to up-regulate ccnb2 promoter activity. Finally, we report an increased CCNB2 expression in human pituitary adenomas of different histotypes that is directly correlated with HMGA1 and HMGA2 expression. Because cyclin B2 is involved in the regulation of the cell cycle, these results taken together indicate that HMGA-induced cyclin B2 overexpression gives an important contribution to experimental and human pituitary tumorigenesis.
We present three patients with bleeding duodenal tumors who were managed by laparoscopic excision. This represents the largest study of such an experience. The literature is reviewed, and the various technical approaches are discussed.
Preoperative sestamibi (MIBI) and ultrasonography (US) are used to localize parathyroid tumors in patients with primary hyperparathyroidism (pHPT). The intraoperative quick PTH assay (qPTH) has been recommended to determine whether all hyperfunctioning parathyroid tissue has been removed. We questioned whether qPTH improves the results of parathyroidectomy in patients with pHPT. We analyzed 115 unselected patients with pHPT without a family history or multiple endocrine neoplasia but who had undergone parathyroidectomy. All 115 patients had successful operations without complications. Of these patients, 88 (77%) had solitary adenomas, 13 had double adenomas, 1 had triple adenomas, 12 had hyperplasia, and 1 had carcinoma. Overall, MIBI was correct in 72% (76/106), US in 49% (49/99), and qPTH in 80% (92/115). For preoperative studies showing a single tumor, MIBI was correct in 83% (73/88), US was correct in 71% (45/63), and combined MIBI and US were correct in 95% (37/39). Adding qPTH in this subgroup did not improve the successful focused approach: 70% for MIBI, 65% for US, and 87% for combined MIBI and US. However, adding qPTH improved the overall success of parathyroidectomy (MIBI 92%, US 86%, combined MIBI and US 97%), but at the cost of unnecessary further exploration (MIBI 13%, US 6%, combined MIBI and US 8%). We conclude that when the same solitary tumor is identified by both MIBI and US, a focused exploration can be done with a 95% success rate. Adding qPTH to MIBI or US can improve the success rate but at a significant cost. General exploration of all parathyroid glands, however, has the highest success rate (100%).