Stable long-term blood formation by stem cells in murine steady-state hematopoiesis

Hematopoietic stem cells (HSCs) generate all mature blood cells during the whole lifespan of an individual. However, the clonal contribution of individual HSC and progenitor cells in steady-state hematopoiesis is poorly understood. To investigate the activity of HSCs under steady-state conditions, murine HSC and progenitor cells were genetically marked in vivo by integrating lentiviral vectors (LVs) encoding green fluorescent protein (GFP). Hematopoietic contribution of individual marked clones was monitored by determination of lentiviral integration sites using highly sensitive linear amplification-mediated-polymerase chain reaction. A remarkably stable small proportion of hematopoietic cells expressed GFP in LV-injected animals for up to 24 months, indicating stable marking of murine steady-state hematopoiesis. Analysis of the lentiviral integration sites revealed that multiple hematopoietic clones with both myeloid and lymphoid differentiation potential contributed to long-term hematopoiesis. In contrast to intrafemoral vector injection, intravenous administration of LV preferentially targeted short-lived progenitor cells. Myelosuppressive treatment of mice prior to LV-injection did not affect the marking efficiency. Our study represents the first continuous analysis of clonal behavior of genetically marked hematopoietic cells in an unmanipulated system, providing evidence that multiple clones are simultaneously active in murine steady-state hematopoiesis. Stem Cells2012;30:1961-1970.     

Implementation of a Tc-99m and Ce-139 scanning line source for attenuation correction in SPECT using a dual opposing detector scintillation camera

Image degradation during single photon emission computed tomography (SPECT) due to attenuation and Compton scatter of photons can cause clinical image artifacts and will also result in inaccurate quantitative data. Therefore attenuation correction methods recently received wide interest. Transmission imaging can be performed to obtain the attenuation coefficients of a nonhomogeneous attenuating medium accurately. The aim of this study was firstly to evaluate the imaging characteristics of the scanning line source assembly. The results obtained with Tc-99m and Ce-139 were compared. Secondly the calculated attenuation coefficients were compared with known values from literature, using Tc-99m and Ce-139 as transmission sources. Lastly the method of acquiring simultaneous transmission and emission data was investigated. This study shows that an attenuation coefficient map can be obtained using a scanning line source for transmission imaging with a dual opposing detector camera. The imaging characteristics of Tc-99m and Ce-139 as transmission sources are similar. The resolution obtained with the Ce-139 line source was poorer than that obtained with the Tc-99m line source. A linear relationship was found between CT numbers and attenuation coefficients for transmission images using both Tc-99m and Ce-139 line sources. The attenuation coefficient value for water was underestimated by 1% using the Tc-99m transmission source and underestimated by 10% using Ce-139 as transmission source. This underestimation of attenuation coefficient values was also obtained in the human study. A myocardial perfusion study processed without and with attenuation correction clearly demonstrated the effect of the attenuation correction in the inferior myocardial region. The potential of using a scanning line source as transmission source with a dual opposing detector camera has been demonstrated in this study. The transmission source, Ce-139 was successfully introduced in this investigation for simultaneous acquisition of transmission and emission data.     

A tissue specific IL-1 receptor antagonist homolog from the IL-1 cluster lacks IL-1, IL-1ra, IL-18 and IL-18 antagonist activities

Interleukin (IL)-1-like protein 1 (IL-1L1) is a 155-amino acid protein that shares 27% identity with IL-1beta and 47% with IL-1 receptor antagonist (IL-1ra). A 2.7-kb IL-1L1 mRNA was cloned from human placenta and is detectable in the trophoblastic cell line JEG-3, in macrophages and in endotoxin-stimulated monocytes. Expression of IL-1L1 is much less abundant and less widespread than IL-1ra. We have determined the human and mouse IL-1L1 cDNA sequences and the complete sequence of the human gene, IL1L1. IL1L1 consists of four coding exons, has two alternative non-coding first exons, lies between IL1B and IL1RN, is orientated in the same direction as IL1RN and is separated from it by approximately 53 kb. The predicted IL-1L1 protein lacks both signal sequence and glycosylation signals. A 17-kDa protein was recovered by immunoprecipitation with IL-1L1-specific antibodies from JEG-3. IL-1L1 did not stimulate IL-6 production from primary human fibroblasts or human umbilical vein endothelial cells nor did it block the IL-1alpha or IL-1beta-dependent activation of IL-6 expression. We conclude, contrary to a recent suggestion made by others, that IL-1L1 is not a functional IL-1ra. IL-1L1 also had no detectable agonistic or antagonistic effect on IFN-gamma production in response to IL-18 in KG-1 cells.     

Causal attributions among patients undergoing coronary artery bypass surgery: gender aspects and relation to depressive symptomatology

Causal attributions made by patients for their coronary heart disease may contribute to gender differences in emotional adjustment. The purpose of this study was to determine gender differences in causal attributions and to analyze the associations between causal attributions and depressive symptomatology in patients undergoing coronary artery bypass graft (CABG) surgery. Nine hundred and seventy-nine patients (mean age 66.8 years, 19.9% women) completed a modified version of the Illness Perception Questionnaire (IPQ) and the depression module of the Patient Health Questionnaire (PHQ-9) 1–3 days before CABG-surgery and 1 year after surgery. Men were more likely to name their health behavior (men: 40.2%, women: 26.9%, P < .001) as a cause of disease, whereas women were more likely to cite destiny (women: 34.7%, men: 25.7%, P = .012). Regression analyses showed cross-sectional and longitudinal associations of attributions with depressive symptomatology which were independent of gender, sociodemographic and clinical variables. Attribution to personality and stress were associated with an increase in depressive symptomatology. Causal attributions may present a valuable approach for identifying patients at risk for depression and the implementation of targeted interventions.     

Renal dysfunction in methylmalonic acidurias: review for the pediatric nephrologist

Methylmalonic acidurias are a heterogeneous group of inborn errors of branched-chain amino acid metabolism. Depending on the underlying etiology, acute or chronic renal disease constitutes major (long-term) complications. In recent decades, overall survival has improved due to optimized treatment strategies based on the use of standardized emergency protocols and dialysis techniques. The majority of these patients, especially those having mut°, cblB, and cblA deficiency, are at increased risk of developing chronic kidney disease secondary to tubulointerstitial nephritis to require hemo- or peritoneal dialysis. Kidney and/or liver transplantation, as organ replacement, or even gene therapy on a limited scale, are controversially discussed treatment options in methylmalonic acidurias. The pathophysiological basis of renal disease has not been clarified in detail until now, but a severe mitochondrial dysfunction and an impairment of tubular dicarboxylic acid transport due to accumulated toxic metabolic compounds has been recently proposed. Another severe renal complication of methylmalonic acidurias is the occurrence of cblC-associated infantile atypical hemolytic syndrome, which can result in acute kidney injury. Close collaboration between (pediatric) nephrologists and metabolic specialists is required for the long-term management of these patients.     

Differential effects of bifrontal tDCS on arousal and sleep duration in insomnia patients and healthy controls

Background

Arousal and sleep represent basic domains of behavior, and alterations are of high clinical importance.

Excitotoxic hippocampal neuron loss following sustained electrical stimulation of the perforant pathway in the mouse

Prolonged electrical stimulation of the perforant pathway in the rat evokes epileptiform discharges in dentate granule cells and irreversibly damages hilar neurons. In this in vivo study, we demonstrate that similar perforant path stimulation in C57Bl/6 mice causes the same pattern of hippocampal neuron loss. Therefore, this mouse model of seizure-induced hippocampal injury can be used for a wide variety of studies in genetically altered conditions not available in rats.     

Validation of a postoperative prognostic model consisting of tumor microvascular invasion, size, and grade to predict disease-free and cancer-specific survival of patients with surgically resected renal cell carcinoma

Objectives:   To determine the value of microvascular invasion, tumor size, and Fuhrman grade to predict the survival of patients with surgically resected renal cell carcinoma (RCC).
Methods:   A total of 771 consecutive patients (T1–4, Nx, M0) were retrospectively reviewed. For each patient with RCC, the prognostic Sao Paulo score (SPS) was calculated using the following variables: tumor size (>7 cm vs ≤7 cm), nuclear grading, and microvascular invasion. On the basis of SPS, patients were subdivided into low-risk (LR), intermediate-risk (IR), and high-risk (HR) groups. Disease-free survival (DFS) and cancer-specific survival (CSS) were estimated using the Kaplan–Meier method. Median follow-up was 80 months.
Results:   Median follow-up was 80 months. DFS rates after 5 years were 91.2%, 61.3%, and 51.9% in the original SPS LR, IR, and HR groups, respectively. CSS rates after 5 years were 94.3%, 79.8%, and 58.7%, respectively ( P  < 0.001). Each original SPS constituent revealed a significant influence on DFS and CSS in the multivariate analysis. By modification of the cut-off value of the maximum tumor size from 7 to 5 cm the predictive value of the SPS sum score was marginally enhanced. Using a cut-off value of 5 cm also resulted in a relatively better discrimination between the IR and the HR group regarding DFS and CSS.
Conclusions:   Stratifying RCC patients by SPS into LR, IR, and HR groups provides a clinically useful tool for outcome analysis and risk assessment. However, the prognostic value of the SPS could be enhanced by including a maximum tumor size with a cut-off at 5 cm into the sum score.