Matrix gamma-carboxyglutamic acid protein is a key regulator of PTH-mediated inhibition of mineralization in MC3T3-E1 osteoblast-like cells

As part of its overall function as a major regulator of calcium homeostasis, PTH stimulates bone resorption and inhibits osteoblast-mediated biomineralization. To determine the basis for the inhibitory actions of this hormone, we compared the time course of PTH-dependent inhibition of mineralization in MC3T3-E1 osteoblast-like cells with changes in mRNA levels for several extracellular matrix proteins previously associated either with induction or inhibition of mineralization. Mineralizing activity was rapidly lost in PTH-treated cells ( approximately 30% inhibition after 3 h, 50% inhibition at 6 h). Of the proteins examined, changes in matrix gamma-carboxyglutamic acid protein were best correlated with PTH-dependent inhibition of mineralization. Matrix gamma-carboxyglutamic acid protein mRNA was rapidly induced 3 h after PTH treatment, with a 6- to 8-fold induction seen after 6 h. Local in vivo injection of PTH over the calvaria of mice also induced a 2-fold increase in matrix gamma-carboxyglutamic acid protein mRNA. Warfarin, an inhibitor of matrix gamma-carboxyglutamic acid protein gamma-carboxylation, reversed the effects of PTH on mineralization in MC3T3-E1 cells, whereas vitamin K enhanced PTH activity, as would be expected if a gamma-carboxyglutamic acid-containing protein were required for PTH activity. Levels of the other mRNAs examined were not well correlated with the observed changes in mineralization. Osteopontin, an in vitro inhibitor of mineralization, was induced approximately 4-fold 12 h after PTH addition. Bone sialoprotein mRNA, which encodes an extracellular matrix component most frequently associated with mineral induction, was inhibited by 50% after 12 h of PTH treatment. Osteocalcin mRNA, encoding the other known gamma-carboxyglutamic acid protein in bone, was also inhibited by PTH, but, again, with a significantly slower time course than was seen for mineral inhibition. Taken together, these results show that the rapid inhibition of osteoblast mineralization induced by in vitro PTH treatment is at least in part explained by induction of matrix gamma-carboxyglutamic acid protein.     

Bilateral simultaneous laparoscopic adrenalectomy in Cushing's syndrome: safe, effective, and curative

INTRODUCTION: Surgical morbidity and mortality rates are high in patients with Cushing's syndrome. Nevertheless, simultaneous bilateral laparoscopic adrenalectomy (LA) is feasible in these patients with less morbidity and good long-term results. BACKGROUND AND RESULTS: Consecutive 22 patients who underwent LA for Cushing's syndrome between 2003 and 2010 in our institute were retrospectively studied. Ninteen patients underwent bilateral simultaneous and three underwent unilateral LA. Seven patients had Cushing's syndrome after failed pituitary surgery and five each had ectopic adrenocorticotrophic hormone dependent syndrome and bilateral macronodular hyperplasia respectively. LA was bilaterally done by lateral transabdominal adrenalectomy in 15 patients and retroperitoneal endoscopic adrenalectomy in 4 on the right side. Mean operative time for simultaneous bilateral cases was 199.45±72.43 minutes with mean blood loss of 72.72±48.6 mL. Patients were fit for discharge by the fifth postoperative day from the surgical aspect. Surgical complication rate was 26% that included wound infections in two, port site hernia, pleural effusion, and atelectasis in one each. One patient died of sepsis (5% mortality). Satisfactory metabolic control was achieved in all observable patients in the long term although Addisonian crisis and Nelson syndrome were seen in 26% and 15% respectively. CONCLUSION: LA has all advantages of minimal access surgery in patients with Cushing's syndrome who are immunocompromised and at high risk of delayed wound healing and infections. Magnification decreases the risk of retained adrenal remnants. Despite advances in minimal access surgery, perioperative morbidity continues to be significant for the procedure.     

The meddling microbes midst our medicines

It is not surprising that the complex metabolic machinery of the gut microbiome has accidental, or directed, ability to alter our medicines and influence their efficacy. What is not known is the extent to which this has contributed to drug failures or contraindications, or to the derailment of clinical trials. Some studies are unraveling the mechanisms by which the microbiota alter specific drugs, such as digoxin, and contribute to variations in efficacies between patient populations. Microbiome profiling, therefore, may well become an inevitable arm of all clinical trials in the future.     

Extinction of hemoglobin inducibility in Friend erythroleukemia cells by fusion with cytoplasm of enucleated mouse neuroblastoma or fibroblast cells.

Friend mouse erythroleukemia cells (T3c1-2 and its subline 5000) can be induced to synthesize hemoglobin after treatment with 1.5% (vol/vol) dimethylsulfoxide. When these cells are fused with nonerythroid cells (namely, mouse neuroblastoma or L cells) hemoglobin induction is extinguished. In order to determine if the nucleus of the nonerythroid cell is necessary for this extinction, fusions were performed between mouse erythroleukemia cells and enucleated neuroblastoma or L cells. Hemoglobin induction was reduced or eliminated in clones of these hybrids even after 6 months of continuous culture. These results suggest that the cytoplasm of nonerythroid cells contains factor(s) that extinguish hemoglobin inducibility in erythroleukemic cells and that this new phenotype can be inherited.     

Adult acute lymphoblastic leukemia with near haploidy, hyperdiploidy and Ph positive lines: a rare entity with poor prognosis

Chromosomal ploidies provide a wealth of information with respect to the prognosis of patients with acute lymphoblastic leukemia (ALL). The prognosis is favourable in hyperdiploidy (>50 ALL), whereas pseudodiploidy and hypodiploidy have an overall poor clinical outcome. Near haploid ALL with less than 30 chromosomes in the leukemic blasts has been reported. This is an extremely rare malignancy with an adverse clinical course compared to other lymphoblastic leukemias. We present a case of near haploid ALL in an adult male with a diagnosis of pre-B-cell ALL. The presenting features and relevance to the progression of disease are discussed with respect to the near haploid lines. Occurrence in an adult male and the presence of additional clones with structural abnormalities are both unique to the present study. Caution must be exercised when the hyperdiploid metaphases consists exclusively of tetrasomic chromosomes and morphological examination reveals definite dual populations of large and small lymphoblasts. Despite current developments in ALL therapy, near haploid ALL continues to be a disease with an adverse clinical outcome and newer therapeutic strategies are warranted for better management of the disease.