B lymphopoiesis in the thymus

The thymus has been regarded as the major site of T cell differentiation. We find that in addition to alphabeta and gammadelta T cells, a significant number (approximately 3 x 104 per day) of B220+IgM+ mature B cells are exported from the thymus of C57BL/6 mice. Of these emigrating B cells, we estimate that at least approximately 2 x 104 per day are cells which developed intrathymically, whereas a maximum of approximately 0.8 x 104 per day are cells which circulated through the thymus from the periphery. The thymus possesses a significant number of pro-B and pre-B cells that express CD19, VpreB, lambda5, and pax-5. These B cell progenitors were found in the thymic cortex, whereas increasingly mature B cells were found in the corticomedullar and medullary regions. Other lymphoid cells, including NK cells and lymphoid dendritic cells, are not exported from the thymus at detectable levels. Thus, the thymus contributes to the formation of peripheral pools of B cells as well as of alphabeta and gammadelta T cells.     

Cloning and characterization of two mouse genes with homology to the yeast Sir2 gene

The yeast Sir2 gene encodes a protein (Sir2p) that plays an essential role in silencing regulation at mating-type loci, rDNA, and telomeres. Recent studies have also shown that the protein participates in cell cycle regulation, DNA double-strand break repair, meiotic checkpoint control, and histone deacetylation. Overexpression of wildtype Sir2p in yeast resulted in an extended life span but mutant Sir2p shortened the life span, suggesting its function in aging processes. Sir2p is evolutionarily conserved from prokaryotes to higher eukaryotes. However, its function(s) in mammals remains unknown. To investigate Sir2p function(s) in mice, we cloned and characterized two mouse Sir2-like genes. Our results revealed that the two mouse Sir2-like proteins (mSIR2L2 and mSIR2L3) are most similar to the human Sir2-like proteins SIR2L2 and SIR2L3, respectively. Sir2 core domains are highly conserved in the two proteins and yeast Sir2p; however, the intracellular localizations of both mSIR2L2 and mSIR2L3 differ from that of yeast Sir2p and from one another. The two mouse genes have completely different genomic structures but were mapped on the same chromosome. It seems that the two mouse proteins, though they have Sir2 conserved domains, may function differently than yeast Sir2p.     

Anatomical Brain Images Alone Can Accurately Diagnose Chronic Neuropsychiatric Illnesses

Objective

Diagnoses using imaging-based measures alone offer the hope of improving the accuracy of clinical diagnosis, thereby reducing the costs associated with incorrect treatments. Previous attempts to use brain imaging for diagnosis, however, have had only limited success in diagnosing patients who are independent of the samples used to derive the diagnostic algorithms. We aimed to develop a classification algorithm that can accurately diagnose chronic, well-characterized neuropsychiatric illness in single individuals, given the availability of sufficiently precise delineations of brain regions across several neural systems in anatomical MR images of the brain.

Methods

We have developed an automated method to diagnose individuals as having one of various neuropsychiatric illnesses using only anatomical MRI scans. The method employs a semi-supervised learning algorithm that discovers natural groupings of brains based on the spatial patterns of variation in the morphology of the cerebral cortex and other brain regions. We used split-half and leave-one-out cross-validation analyses in large MRI datasets to assess the reproducibility and diagnostic accuracy of those groupings.

Results

In MRI datasets from persons with Attention-Deficit/Hyperactivity Disorder, Schizophrenia, Tourette Syndrome, Bipolar Disorder, or persons at high or low familial risk for Major Depressive Disorder, our method discriminated with high specificity and nearly perfect sensitivity the brains of persons who had one specific neuropsychiatric disorder from the brains of healthy participants and the brains of persons who had a different neuropsychiatric disorder.

Conclusions

Although the classification algorithm presupposes the availability of precisely delineated brain regions, our findings suggest that patterns of morphological variation across brain surfaces, extracted from MRI scans alone, can successfully diagnose the presence of chronic neuropsychiatric disorders. Extensions of these methods are likely to provide biomarkers that will aid in identifying biological subtypes of those disorders, predicting disease course, and individualizing treatments for a wide range of neuropsychiatric illnesses.     

Randomized placebo-controlled clinical trial of lorcaserin for weight loss in type 2 diabetes mellitus: the BLOOM-DM study

The BLOOM-DM (Behavioral Modification and Lorcaserin for Obesity and Overweight Management in Diabetes Mellitus) study evaluated efficacy and safety of lorcaserin for weight loss in patients with type 2 diabetes. Secondary objectives included evaluations of glycemic control, lipids, blood pressure, and quality of life. This 1-year, randomized, placebo-controlled trial enrolled 604 patients 1:1:1 to placebo, lorcaserin 10 mg once daily (QD) or lorcaserin 10 mg twice daily (BID). Patients were treated with metformin, a sulfonylurea (SFU) or both; had glycated hemoglobin (HbA(1c)) 7-10%; were 18-65 years old; and had BMI 27-45 kg/m(2). Patients received diet and exercise counseling. Safety monitoring included serial echocardiograms. Mean (± SD) age was 52.7 ± 8.7; 54.2% were women; 60.5% were white, 20.9% were African American, and 13.8% were Hispanic. Mean (± SD) weight was 103.6 ± 17.8 kg; BMI was 36.0 ± 4.5 kg/m(2). Most patients (91.7%) took metformin; 50.2% took a SFU. More patients lost ≥5% body weight with lorcaserin BID (37.5%; P < 0.001) or lorcaserin QD (44.7%; P < 0.001) vs. placebo (16.1%; modified intent to treat (MITT)/last observation carried forward (LOCF)). Least square mean (± SEM) weight change was -4.5 ± 0.35% with lorcaserin BID and -5.0 ± 0.5% with lorcaserin QD vs. -1.5 ± 0.36% with placebo (P < 0.001 for each). HbA(1c) decreased 0.9 ± 0.06 with lorcaserin BID, 1.0 ± 0.09 with lorcaserin QD, and 0.4 ± 0.06 with placebo (P < 0.001 for each); fasting glucose decreased 27.4 ± 2.5 mg/dl, -28.4 ± 3.8 mg/dl, and 11.9 ± 2.5 mg/dl, respectively (P < 0.001 for each). Symptomatic hypoglycemia occurred in 7.4% of patients on lorcaserin BID, 10.5% on lorcaserin QD, and 6.3% on placebo. Common adverse events were headache, back pain, nasopharyngitis, and nausea. Lorcaserin was associated with significant weight loss and improvement in glycemic control in patients with type 2 diabetes.     

Functional repurposing revealed by comparing S. pombe and S. cerevisiae genetic interactions

We present a genetic interaction map of pairwise measures including ～40% of nonessential S. pombe genes. By comparing interaction maps for fission and budding yeast, we confirmed widespread conservation of genetic relationships within and between complexes and pathways. However, we identified an important subset of orthologous complexes that have undergone functional "repurposing": the evolution of divergent functions and partnerships. We validated three functional repurposing events in S. pombe and mammalian cells and discovered that (1) two lumenal sensors of misfolded ER proteins, the kinase/nuclease Ire1 and the glucosyltransferase Gpt1, act together to mount an ER stress response; (2) ESCRT factors regulate spindle-pole-body duplication; and (3) a membrane-protein phosphatase and kinase complex, the STRIPAK complex, bridges the cis-Golgi, the centrosome, and the outer nuclear membrane to direct mitotic progression. Each discovery opens new areas of inquiry and-together-have implications for model organism-based research and the evolution of genetic systems.     

hESC-Derived Thalamic Organoids Form Reciprocal Projections When Fused with Cortical Organoids

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