A pseudohypoparathyroidism type Ia patient with normocalcemia

Pseudohypoparathyroidism type Ia (PHP-Ia), one of 4 types of PHP, is a genetic disease characterized by clinical hypoparathyroidism caused by parathyroid hormone (PTH) resistance. In addition, patients with PHP-Ia show resistance to other hormones as well as Albright's hereditary osteodystrophy (AHO), a constellation of features including short stature, obesity, brachydactyly, ectopic ossifications, and/or mental retardation. Hypocalcemia is one of the hallmarks of PHP-Ia, but several PHP-Ia patients have been described to have normocalcemia. We encountered a 10-year-old girl with typical Albright's hereditary osteodystrophy with round face, short stature, brachydactyly, and obesity. Biochemical examination showed normocalcemia and increased PTH levels. Ellsworth-Howard test did not show any responses of urinary cAMP and phosphate. Based on these findings, she was diagnosed as having PHP-Ia with normocalcemia. Sequencing analysis of the GNAS gene identified a heterozygous missense mutation in exon 13 (R385H), which was previously reported in a PHP-Ia patient. The exact reason for her normocalcemia is not determined, but we must recognize heterogeneous biochemical findings even in PHP-Ia.     

Targeted disruption of p70s6k defines its role in protein synthesis and rapamycin sensitivity

Here, we disrupted the p70 S6 kinase (p70^s6k) gene in murine embryonic stem cells to determine the role of this kinase in cell growth, protein synthesis, and rapamycin sensitivity. p70^s6k−/− cells proliferated at a slower rate than parental cells, suggesting that p70^s6k has a positive influence on cell proliferation but is not essential. In addition, rapamycin inhibited proliferation of p70^s6k−/− cells, indicating that other events inhibited by the drug, independent of p70^s6k, also are important for both cell proliferation and the action of rapamycin. In p70^s6k−/− cells, which exhibited no ribosomal S6 phosphorylation, translation of mRNA encoding ribosomal proteins was not increased by serum nor specifically inhibited by rapamycin. In contrast, rapamycin inhibited phosphorylation of initiation factor 4E-binding protein 1 (4E-BP1), general mRNA translation, and overall protein synthesis in p70^s6k−/− cells, indicating that these events proceed independently of p70^s6k activity. This study localizes the function of p70^s6k to ribosomal biogenesis by regulating ribosomal protein synthesis at the level of mRNA translation.     

Involvement of aldosterone and mineralocorticoid receptors in rat mesangial cell proliferation and deformability

We demonstrated recently that chronic administration of aldosterone to rats induces glomerular mesangial injury and activates mitogen-activated protein kinases including extracellular signal-regulated kinases 1/2 (ERK1/2). We also observed that the aldosterone-induced mesangial injury and ERK1/2 activation were prevented by treatment with a selective mineralocorticoid receptor (MR) antagonist, eplerenone, suggesting that the glomerular mesangium is a potential target for injuries induced by aldosterone via activation of MR. In the present study, we investigated whether MR is expressed in cultured rat mesangial cells (RMCs) and involved in aldosterone-induced RMC injury. MR expression and localization were evaluated by Western blotting analysis and fluorolabeling methods. Cell proliferation and micromechanical properties were determined by [3H]-thymidine uptake measurements and a nanoindentation technique using an atomic force microscope cantilever, respectively. ERK1/2 activity was measured by Western blotting analysis with an anti-phospho-ERK1/2 antibody. Protein expression and immunostaining revealed that MR was abundant in the cytoplasm of RMCs. Aldosterone (1 to 100 nmol/L) dose-dependently activated ERK1/2 in RMCs with a peak at 10 minutes. Pretreatment with eplerenone (10 micromol/L) significantly attenuated aldosterone-induced ERK1/2 phosphorylation. Aldosterone (100 nmol/L) treatment for 30 hours increased [3H]-thymidine incorporation and decreased the elastic modulus, indicating cellular proliferative and deforming effects of aldosterone, respectively. These aldosterone-induced changes in cellular characteristics were prevented by pretreatment with eplerenone or an ERK (MEK) inhibitor, PD988059 (100 micromol/L). The results indicate that aldosterone directly induces RMC proliferation and deformability through MR and ERK1/2 activation, which may contribute to the pathogenesis of glomerular mesangial injury.     

Isolation of measles virus from middle ear fluid of infants with acute otitis media

Measles virus was isolated from the middle ear fluid (MEF) of two infant cases of acute otitis media (AOM) associated with measles. This is the first report on the isolation of measles virus from the MEF in patients with AOM, and possibility of the measles virus as a causative agent of AOM was suggested.     

Novel approach of laparoscopic and endoscopic cooperative surgery (LECS) for cholecystectomy

Background: Endoscopic submucosal dissection (ESD) techniques, such as generating an artificial space between digestive tract layers for safer dissection, were thought to be safer for the resection of organs in cholecystectomy. We investigated whether combinations of endoscopic techniques and laparoscopic techniques could be performed more safely and rapidly.

Material and methods: Laparoscopic and endoscopic cooperative-cholecystectomy (LEC-chole) and conventional laparoscopic cholecystectomy (Lapa-chole) were performed in six dogs. Operation time was defined as the time from the creation of the first port to the retrieval of the resected gallbladder (GB); and GB bed dissection time was the time from local injection of natural saline to the clipping of the cystic duct. The main roles of the endoscope in LEC-chole were to obtain a sufficient cutting space via local injection of natural saline to the GB bed and to monitor the operative view without laparoscopic camera, thus omitting the umbilical port.

Results: The operation times were 60?±?18.3?minutes for LEC-chole and 95?±?7.0 for Lapa-chole (p?=?.036). The GB bed dissection times were 31?±?8.54?minutes in LEC-chole and 50.6?±?7.37?minutes in Lapa-chole (p?=?0.048). There were significant differences in liver damage and bleeding (p?=?0.116), but there were no significant differences in one-month survival.

Conclusions: The application of LEC-chole may be expanded to cholecystectomy.     

Identification of low-dose responsive metabolites in X-irradiated human B lymphoblastoid cells and fibroblasts

Ionizing radiation (IR) induces cellular stress responses, such as signal transduction, gene expression, protein modification, and metabolite change that affect cellular behavior. We analyzed X-irradiated human Epstein-Barr virus-transformed B lymphoblastoid cells and normal fibroblasts to search for metabolites that would be suitable IR-responsive markers by Liquid Chromotography–Mass spectrometry (LC–MS). Mass spectra, as analyzed with principal component analysis, showed that the proportion of peaks with IR-induced change was relatively small compared with the influence of culture time. Dozens of peaks that had either been upregulated or downregulated by IR were extracted as candidate IR markers. The IR-changed peaks were identified by comparing mock-treated groups to 100 mGy-irradiated groups that had recovered after 10 h, and the results indicated that the metabolites involved in nucleoside synthesis increased and that some acylcarnitine levels decreased in B lymphoblastoids. Some peaks changed by as much as 20 mGy, indicating the presence of an IR-sensitive signal transduction/metabolism control mechanism in these cells. On the other hand, we could not find common IR-changed peaks in fibroblasts of different origin. These data suggest that cell phenotype-specific pathways exist, even in low-dose responses, and could determine cell behavior.