Association of decreased calcium-sensing receptor expression with proliferation of parathyroid cells in secondary hyperparathyroidism

BACKGROUND: The down-regulation of both calcium-sensing receptor (CaSR) and vitamin D receptor (VDR) in parathyroid (PT) glands of secondary hyperparathyroidism (HPT) caused by chronic renal failure has been associated with PT hormone hypersecretion as well as PT hypergrowth. To clarify the predominance of decreased expression of CaSR and VDR in the high proliferative activity of PT glands, we examined the relationship between the expression of both receptors and proliferative activity in human PT glands. METHODS: Serial sections of 56 PT glands, including 52 glands from secondary HPT and 4 normal PT glands resected together with thyroid carcinoma, were examined immunohistochemically with specific antibodies against CaSR, VDR, and Ki67. The Ki67-positive cell number was counted and expressed as the Ki67 score. The CaSR and VDR expressions were semiquantitatively analyzed. RESULTS: The expressions of both CaSR and VDR were markedly decreased in PT glands of secondary HPT, while the Ki67 score was significantly higher than it was in normal controls. When hyperplastic glands were classified into two subgroups, with [N(+)] or without [N(-)] nodular formation, CaSR expression was significantly decreased in N(+), while VDR expression was not different. Multiple regression analyses revealed that the decreased expression of CaSR could contribute significantly to the high proliferative activity, even if VDR expression was taken into account. CONCLUSION: The decrease in CaSR expression is associated with the high proliferative activity of PT glands in secondary HPT, independently of the decreased VDR expression. These findings provide a new insight into the pathogenesis of PT hyperplasia, which is refractory to vitamin D therapy in patients with severe secondary HPT.     

A new case of malonyl coenzyme A decarboxylase deficiency presenting with cardiomyopathy

A new case of mitochondrial malonyl coenzyme A decarboxylase deficiency is described. The patient presented with an initial episode of metabolic acidosis, seizures, hypoglycemia, and cardiac failure at 2 months of age which slowly resolved. Subsequent evaluations at 4 years of age for developmental delay revealed a prominent elevation of malonic acid in urine. Malonyl carnitine was also elevated. The activity of malonyl CoA decarboxylase in cultured fibroblasts was 7% of normal. Conclusion Malonyl CoA decarboxylase deficiency may result in inhibition of fatty acid oxidation, which may account for the cardiomyopathy. Received: 12 April 1996 / Accepted: 24 September 1996     

Docosahexaenoic acid and vitamin E can reduce human monocytic U937 cell apoptosis induced by tumor necrosis factor

The effects of polyunsaturated fatty acids and vitamin E on tumor necrosis factor (TNF)-induced apoptosis of human monocytic U937 cells was explored to assess to what extent these nutrients could attenuate apoptosis. Preincubation of U937 cells with arachidonic acid for 24 h did not affect TNF-induced apoptosis. Eicosapentaenoic acid slightly but significantly reduced the proportion of apoptotic cells only when apoptosis was induced by TNF without cycloheximide (CHI). In contrast, preincubation with docosahexaenoic acid (DHA) greatly (40 approximately 70%) attenuated apoptosis induced by stimulation with either TNF or TNF + CHI for 3 h. The inhibition of apoptosis was accompanied by enrichment of DHA in membrane phospholipids, indicating that DHA probably exerted its inhibitory activity after being incorporated into the phospholipids. Vitamin E also played a role as a partial inhibitor of apoptosis 3 h after TNF addition. This vitamin could further reduce the apoptosis of DHA-treated cells, and such an additive effect was obvious when apoptosis was induced at a low frequency. Longer-range stimulation of U937 cells with TNF showed that inhibition of apoptosis by preincubating cells with either DHA or vitamin E was not significant 9 h after TNF addition, but that preincubation with both DHA and vitamin E could reduce the proportion of apoptotic cells even at this time point. Our findings suggested that ingestion of nutrients such as DHA and vitamin E might exert beneficial effects on organ dysfunction associated with various TNF-related diseases.     

Plasma cell leukemia with lobulated nuclei: One case report

The case of an 80-year-old man with plasma cell leukemia characterized by basophilic cytoplasm, and extensive lobulated nuclei is described. In spite of the peculiar morphologic nuclei, the diagnosis was based on the presence of M protein and Bence Jones protein in the serum and urine, immunophenotypic characteristics, immunoglobulin gene rearrangement, and findings of transmission electron microscopy.     

Spontaneous regression of malignant pleural mesothelioma

We describe the spontaneous regression of a malignant pleural mesothelioma with left pleural effusion, chest pain, and a high fever (38° to 39°C) in a 37-year-old man. The patient was referred to us because multiple nodules were seen on his chest radiograph after he was successfully treated with thoracocentesis and conventional antibiotic therapy for pleural effusion. Our diagnosis was malignant pleural mesothelioma, based on histologic findings in a biopsy specimen obtained during thoracoscopy. Interestingly, the tumors markedly regressed without treatment, and the patient was doing well more than 5 months after the cancer was diagnosed. The spontaneous regression of malignant pleural mesothelioma is rare, and this may represent the first case report.     

Primary pleomorphic adenoma in posterior cranial fossa

A 35-year-old woman had an intradural tumor in the posterior fossa adjacent to the posterior wall of the left pyramidal bone, which was totally removed and histologically diagnosed as a pleomorphic adenoma. Follow-up examination for 2 years showed no recurrence of the tumor. There was no primary lesion in any other gland of the body, and therefore there is no alternative but to conclude a “migration” of some gland cells. The pathogenesis of this tumor remains unclassified.     

Globotriaosyl Ceramide and Globoside as Major Glycolipid Components of Fibroblasts in Scirrhous Gastric Carcinoma Tissues

Scirrhous gastric cancer is characteristic in that cancer cells proliferate and invade with prominent fibrosis. To search for the expression of specific carbohydrate chains in scirrhous gastric cancer, we have examined the glycosphingolipid composition of scirrhous cancer tissues (n=10) in comparison with that of non-scirrhous cancer tissues (n=10) by means of two-dimensional thin layer chromatography, followed by fast atom bombardment mass spectrometry of the individual glycolipids and immunostaining analysis. The major neutral glycosphingolipids from scirrhous gastric cancer tissues were identified as ceramide monohexoside, ceramide dihexoside, globotriaosyl ceramide (Gb₃) and globoside (Gb₄), while the major acidic glycosphingolipids were II³ Neu-Acα-LacCer, II³ NeuAcα₂-LacCer and sulfatide. Relative concentrations of Gb₃ and Gb₄ in scirrhous gastric cancer tissues (Gb₃+ Gb₄=58%) were two times higher than those in non-scirrhous gastric cancer tissues (29%). Orthotopic fibroblasts cloned from scirrhous gastric cancer tissues showed similar high concentrations of Gb₃ and Gb₄ to scirrhous gastric cancer tissues. Furthermore, immunohistochemical study revealed that Gb₃ and Gb₄ were expressed intensely on the fibroblasts. On the other hand, analysis of glycosphingolipids in four scirrhous gastric cancer cell lines yielded the following results. i) The contents of Gb₃ and Gb₄ were low (6%), compared with orthotopic fibroblasts (62%). ii) Significant amounts of Le^a (pentaglycosylceramide) and Le^b (hexa- and heptaglycosylceramides), which could not be detected in scirrhous cancer tissues, were observed. The results show that the major neutral glycosphingolipids such as Gb₃ and Gb₄ of scirrhous gastric cancer tissues were derived from orthotopic fibroblasts and not from the cancer cells.     

Morphological change in the MNNG-treated rat gastric mucosa

To investigate the process of carcinogenesis in gastric cancer, we studied the histological features of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-treated rats. Samples of the gastric mucosa from both MNNG-treated and control rats were histologically examined every 2 months, for 10 months. In 40% of the MNNG-treated rats, atrophy in the gastric mucosa was observed after 2 months, and regenerative epithelium was observed after 4 months, followed by adenomatous proliferation and disappearance of the tight junction electron microscopically after 6 months. A small intestinal cancer had developed in 2 rats at 6 months. While gastric cancer had developed in 3 rats at 8 months, and in one of these 3 rats, peritoneal dissemination was observed macroscopically and histologically. These results suggested that adenomatous proliferation and disappearance of the tight junction observed electron microscopically were characteristic pathological features of precancerous lesions in the stomach in MNNG-treated rat.     

Primary gastric lymphoma: a clinicopathological study

A retrospective study of 25 patients treated for primary gastric lymphoma was made to investigate a number of problems related to treatments and report the factors influencing prognosis. In the 5-year-survival rate according to Working Formulation classification, either survival rate of low-grade type or intermediate-grade type was higher than that of high-grade type. Both the 5-year-survival rate of cases without lymph node metastasis and that of cases that involved perigastric lymph nodes were higher than that of cases that involved distant gastric lymph nodes. Those surviving five years after perigastric lymph node metastasis had received D3 or D4 dissection and postoperative multicombined chemotherapy. Tumors invading only to the submucosal layer had received D2 dissection and were not treated by postoperative multicombined chemotherapy, and recurrence was not recognized in these cases. Of 9 cases infiltrating into the musclaris propria or serosa without lymph node metastasis, 8 cases were treated by postoperative multicombined chemotherapy and were alive without recurrence, but one case without postoperative multicombined chemotherapy died by recurrence. Therefore, adequate therapy for gastric lymphoma with infiltrating into submucosal layer is gastrectomy with D2 lymph node dissection, and postoperative multicombined chemotherapy is not necessary. The cases with perigastric lymph node metastasis, or the cases with invading from muscularis propria to serosa require D3 or D4 lymph node dissection with postoperative multicombined chemotherapy. But the cases with distant gastric lymph node metastasis or invading adjacent structure or high-grade type histologically (WF classification) require preoperative chemotherapy.