β-Catenin Preserves the Stem State of Murine Bone Marrow Stromal Cells Through Activation of EZH2

During bone marrow stromal cell (BMSC) differentiation, both Wnt signaling and the development of a rigid cytoskeleton promote commitment to the osteoblastic over adipogenic lineage. β-catenin plays a critical role in the Wnt signaling pathway to facilitate downstream effects on gene expression. We show that β-catenin was additive with cytoskeletal signals to prevent adipogenesis, and β-catenin knockdown promoted adipogenesis even when the actin cytoskeleton was depolymerized. β-catenin also prevented osteoblast commitment in a cytoskeletal-independent manner, with β-catenin knockdown enhancing lineage commitment. Chromatin immunoprecipitation (ChIP)-sequencing demonstrated binding of β-catenin to the promoter of enhancer of zeste homolog 2 (EZH2), a key component of the polycomb repressive complex 2 (PRC2) complex that catalyzes histone methylation. Knockdown of β-catenin reduced EZH2 protein levels and decreased methylated histone 3 (H3K27me3) at osteogenic loci. Further, when EZH2 was inhibited, β-catenin's anti-differentiation effects were lost. These results indicate that regulating EZH2 activity is key to β-catenin's effects on BMSCs to preserve multipotentiality. © 2020 American Society for Bone and Mineral Research.     

Comparison of the roles of insulin and insulin-like growth factor I in casein gene expression and in the development of alpha-lactalbumin and glucose transport activities in the mouse mammary epithelial cell

The concentration-activity profiles for insulin and insulin-like growth factor I (IGF-I; in the presence of and insulin-like growth factor I (IGF-I; in the presence of hydrocortisone and PRL) have been compared in terms of the accumulation of beta-casein mRNA, total casein synthesis, and alpha-lactalbumin and basal carrier-mediated glucose transport activities in mammary epithelial cells from midpregnant mice. For the accumulation of the casein mRNA and the induction of casein synthesis and alpha-lactalbumin activity, the insulin ED50 is 1-2 ng/ml, while that for IGF-I is 10- to 20-fold greater. The effects of insulin and IGF-I are not additive in these instances. For the induction of basal carrier-mediated glucose transport, the insulin ED50 is 8 ng/ml, and that for IGF-I is 16 ng/ml. Either factor can induce transport activity up to the level present in the cells from 2-day lactating mice. In this instance the effects are additive; insulin and IGF-I together can induce the transport up to the 10-day lactating level.     

Magnetic tests for magnetosome chains in Martian meteorite ALH84001

Transmission electron microscopy studies have been used to argue that magnetite crystals in carbonate from Martian meteorite ALH84001 have a composition and morphology indistinguishable from that of magnetotactic bacteria. It has even been claimed from scanning electron microscopy imaging that some ALH84001 magnetite crystals are aligned in chains. Alignment of magnetosomes in chains is perhaps the most distinctive of the six crystallographic properties thought to be collectively unique to magnetofossils. Here we use three rock magnetic techniques, low-temperature cycling, the Moskowitz test, and ferromagnetic resonance, to sense the bulk composition and crystallography of millions of ALH84001 magnetite crystals. The magnetic data demonstrate that although the magnetite is unusually pure and fine-grained in a manner similar to terrestrial magnetofossils, most or all of the crystals are not arranged in chains.     

Oligodendroglioma presenting with intradural spinal metastases: an unusual cause of cauda equina syndrome

We report a 37-year-old man with a primary intracranial oligodendroglioma presenting later with symptomatic multiple cerebrospinal fluid (CSF) intradural drop spinal metastases. This patient initially presented in 2006 with complex partial seizures. Initial histology demonstrated World Health Organization (WHO) grade 2 oligodendroglioma. The patient had further generalised seizures 7 months after initial tumour resection. MRI at that time confirmed tumour recurrence. The patient underwent a repeat craniotomy. Histology showed anaplastic transformation to a WHO grade 3 oligodendroglioma. About 30 months after his initial presentation, the patient developed a focal neurological deficit in the left leg with associated retention of urine. MRI of the neuraxis demonstrated widespread leptomeningeal metastatic drop deposits within the spinal canal. We discuss the mechanisms involved in tumour dissemination throughout the CSF. We also review the relevant literature regarding this phenomenon.     

The effect of a supplementary protein food containing fish flour,groundnut flour and bengal gram flour and fortified with vitamins on the growth and nutritional status of children

Summary A feeding experiment extending over a period of six months was carried out on 58 boys, aged 6 to 12 years, in a local boarding home in Mysore, to assess the effects of supplementing their diet daily, with 40 gm. of a protein food based on 2∶1∶1 blend of groundnut flour, Bengal gram flour and fish flour (from oil sardine) fortified with vitamins A and D, thiamine and riboflavin. The children were paired according to initial height and weight and the members of each pair allotted at random to the control and experimental groups. Values for weight, height, nutritional status, haemoglobin level and red blood cell count were recorded at the beginning and end of the experiment, for subjects in the control and experimental groups. All the children in the experimental group relished the protein supplement and none complained of digestive trouble. A highly significant increase in height, weight, red blood cell count and haemoglobin level of the subjects receiving the protein food supplement was observed as compared with the control group. Eighty per cent. of the subjects in the experimental group improved in their nutritional status as compared with only seventeen per cent. in the control group. None in the experimental group showed deterioration whereas seventeen per cent. of the subjects in the control group showed deterioration in their nutritional status. From the Central Food Technological Research Institute, Mysore. An erratum to this article is available at .     

Severe hypothyroidism after coronary artery bypass grafting

A 56-year-old man with unstable angina underwent urgent coronary artery bypass grafting. The patient required reintubation and prolonged ventilation because of persistent drowsiness and hypotension. The patient was weaned off the ventilator and extubated; however, he remained drowsy and lethargic. Neurologic examination, electroencephalogram, and computed tomography scan of the brain did not show any organic cause of his depressed neurologic status. His metabolic profile revealed severe hypothyroidism. The patient responded well to oral thyroxine. We report the unusual manner in which hypothyroidism presented in the patient. A high index of suspicion is required to diagnose and treat this complication.     

Emergency surgery after percutaneous transmitral commissurotomy: operative versus echocardiographic findings, mechanisms of complications, and outcomes

OBJECTIVE: This study was undertaken to determine the clinical profile of patients undergoing emergency surgery after balloon mitral valvotomy, to note operative findings and compare them with those of transthoracic echocardiography, to describe the mechanisms of complications, and to describe outcomes. METHODS: A retrospective study was undertaken of patients requiring emergency surgery after percutaneous mitral valvotomy with an Inoue balloon from January 1990 to December 2003. The data analyzed included demographic variables, causes and clinical presentations of complications, and outcome. In 14 consecutive cases of mitral regurgitation, an observational study comparing the operative findings with echocardiography was also undertaken. RESULTS: In 1388 cases of valvotomy, complications necessitating urgent surgery occurred in 31 cases (2.2%). Acute mitral regurgitation occurred in 23 cases (74.2%), and cardiac tamponade occurred in 8 cases (25.8%). Mitral regurgitation was due to leaflet tearing in all cases: anterior leaflet in 20 cases and posterior leaflet in 3 cases. Hypotension, orthopnea, and pulmonary edema were the clinical presentation for mitral regurgitation. Transthoracic echocardiography underestimated the severity of mitral valve pathology. Bilateral severe commissural fusion and pliable leaflet with paracommissural calcium was seen in anterior leaflet tearing. Cardiac tamponade with hemodynamic compromise occurred as a result of left atrial perforation in 6 cases, right atrial perforation in 1 case, and left ventricular perforation in 1 case. High septal puncture led to atrial perforation. Operative mortality was 9.6%, and low cardiac output developed in 29%. CONCLUSION: Acute mitral regurgitation and cardiac tamponade were the causes of emergency surgery after balloon valvotomy. Transthoracic echocardiography underestimated the severity of valve pathology.