bluuebunny/crossref_metadata_2025_split huggingface dataset:
PTPN2, Distinctively Expressed in GCB-Like and ABC-Like DLBCL, Is the Nuclear Phosphatase of STAT6.
Authors: Lossos Izidore S. , Lu XiaoQing , Tiganis Tony 
Published: April 2020

Abstract
Gene expression profiling studies sub-classified diffuse large B-cell lymphomas (DLBCL) into two clinically distinct types: Germinal Center B cell (GCB)-like and Activated B-cell (ABC)-like tumors, characterized by long and short survival, respectively. We have recently reported distinct responsiveness of GCB-like and ABC-like DLBCL cell lines to IL-4 stimulation. In GCB-like lymphoma cells, IL-4 leads to nuclear accumulation of phosphorylated signal transducer and activator of transcription 6 (STAT6) and induction of IL-4 target genes, while in ABC-like tumor cells there is an increased nuclear dephosphorylation of pSTAT6 and no induction of IL-4 target genes (Lu et al: Blood2005;105:2924). Furthermore, GCB-like and ABC-like DLBCL tumors exhibit a different expression profile of protein tyrosine phosphatases (PTPs). Among the distinctively expressed PTPs, only 45kDa isoform of protein tyrosine phosphatase non-receptor type 2 (PTPN2, also known as T-cell PTP-TCPTP) localizes to the nucleus. Despite PTPN2–45 having an apparent exclusively nuclear localization in resting cells, specific stimuli can induce PTPN2–45 shuttling to the cytoplasm, thus gaining access to the cytoplasmic substrates, such as the epidermal growth factor (EGF) receptor, the insulin receptor, Src family kinases, adaptor protein p52 Shc and Janus protein tyrosine kinases (JAK 1 and 3), thereby regulating multiple intracellular signaling pathways. In contrast, STAT1, 5A and 5B are the only to date known PTPN2-45 nuclear substrates. Substrate identification is a crucial step in delineating the functional spectrum of PTPN2 in vivo. Herein, we demonstrate that STAT6 may serve as a physiological nuclear substrate of PTPN2-45. Over-expression of PTPN2 leads to nuclear STAT6 dephosphorylation. By using a nuclear restricted version of PTPN2 (pEGFP-PTPN2), we show that the dephosphorylation of STAT6 is independent of PTPN2 induced JAK dephosphorylation. We demonstrate interactions between endogenous PTPN2 and STAT6 and delineate the STAT6 and PTPN2 protein domains responsible for the interaction: the catalytic domain of PTPN2 and the C terminal transactivation domain of STAT6. Furthermore, we demonstrate that over-expression of PTPN2 ameliorates IL-4 induced expression of its target genes in GCB-like DLBCL tumor cells. We observe tight control of PTPN2 at different differentiation levels of B cell lymphocytes thus suggesting that distinct expression of PTPN2 in GCB-like and ABC-like DLBCL tumors stems from different cellular origin of these lymphomas. Our findings identify STAT6 as a new nuclear target of PTPN2 and suggest that distinct PTPs expression profiles may contribute to different biological characteristics of GCB-like and ABC-like DLBCL.
Survey of Red Blood Cell Transfusion Practices in Medically Ill Patients.
Authors: Yuen Maggie M. , Anderson David R. , Patrick Ward , Rose Caren 
Published: April 2020

Abstract
Although red cell transfusion is a relatively common treatment used in medically ill patients, much is not known about clinical determinants used to guide its use. A cross-sectional self-administered survey was used to assess the red blood cell transfusion practices of academic medical internists, subspecialty physicians and internal medicine residents who practice on the Medical Teaching Unit (MTU) at the Queen Elizabeth II Health Sciences Center, Halifax, Nova Scotia. We evaluated transfusion thresholds before transfusion and the number of red cell units ordered for four clinical scenarios: chronic obstructive pulmonary disease (COPD), coronary artery disease (CAD), gastrointestinal bleeding and delirium. Clinical characteristics were varied to further clarify clinical determinants of transfusion. The response rate among the forty-nine medical internists and subspecialty physicians was 59%. Among internal medicine residents the response rate was 100% (n=14). The primary area of practice for the majority of respondents was general internal medicine. Most staff physicians attended on the MTU for greater than four weeks. Baseline hemoglobin transfusion thresholds averaged from 75.6 +/− 9.8 g/L in a patient with acute delirium to 91.4 +/− 11.4 g/L in the gastrointestinal bleeding scenario. Range of baseline hemoglobin transfusion thresholds within scenarios was as wide as 60 to 120 g/L. Between the four scenarios, baseline hemoglobin transfusion thresholds differed significantly (p&lt;0.03) except between the CAD and gastrointestinal bleeding scenarios. Clinical factors age and gender did not significantly (p&gt;0.05) alter hemoglobin transfusion thresholds in the CAD and delirium scenarios, but were significant (p&lt;0.02) modifiers of hemoglobin transfusion thresholds along with oxygen saturation, lactic acidosis, hemodynamic stability, requirement for urgent surgery, and chronic surgery in all other scenarios. Comparing staff physicians and internal medicine residents, there was no significant difference between the two groups for baseline hemoglobin transfusion thresholds. In conclusion, among physicians caring for medically ill patients, there is significant variation in red blood cell transfusion practices. Consistent with research in the critical care setting, pre-transfusion hemoglobin, along with other clinical factors, continues to be an important determinant of red cell transfusion.
The Common Practice of Transfusing 1–2 Units of Fresh Frozen Plasma (FFP) to Patients with Mildly Prolonged Prothrombin Times (PT) Does Not Lead to Clinically Significant Changes in Their PT Values.
Authors: Darabi Kamran , Uhl Lynne 
Published: April 2020

Abstract
INTRODUCTION: Various guidelines define appropriateness of FFP administration based on prothrombin time (PT) greater than 1.5 times normal. However, FFP is often transfused to patients with PTs that are in the upper range of normal or mildly prolonged. There is a paucity of data on whether transfusion of FFP to such patients will change their PT.
METHODS: We retrospectively reviewed all FFP transfusions that were administered to patients with a PT below 17 seconds (normal reference range 11.3–13.6 seconds) at a tertiary care hospital in 2004. Patients were included in our analysis if their PT was measured prior to and within six hours of transfusion and if they received no more than two units of FFP. We identified 143 consecutive cases that met these criteria.
RESULTS: 66 patients received one unit and 77 patients received 2 units of FFP. The median decrease in PT after the infusion of one or two units of FFP was 0.4 seconds and 0.6 seconds respectively. The pretransfusion PTs in 6 patients ranged between 12.2–13 seconds (subgroup 1), in 17 patients 13–14 seconds (subgroup 2), in 46 patients 14–15 seconds (subgroup 3), in 37 patients 15–16 seconds (subgroup 4), and in 37 patients 16–17 seconds (subgroup 5). Patients in subgroups 1 and 2 were noted to have higher PT values after the administration of FFP (median prolongation of 0.6 and 0.1 seconds respectively). The PT shortened in subgroup 3 by 0.4 seconds (median) and in subgroups 4 and 5 by 0.9 seconds (median) when compared to the pretransfusion PT, which represent clinically insignificant corrections.
CONCLUSION: Transfusion of blood products is not without risks; given that PT values of less than 17 seconds do not significantly change following transfusion of one to two units of FFP, this clinical practice should be avoided.
Rational Development of Serologic Assays for Anti-HTLV Antibodies.
Authors: Poiesz Michael J. , Choi David , Hengst James , Ehrlich Garth , Dube Syamalima , Poiesz Bernard J. 
Published: April 2020

Abstract
Both HIV and HTLV virions are comprised mainly of gag proteins (p24 and p19 for HTLV) (Table 1); while both virions lack their primary RNA transcriptional regulatory proteins (Tax and Tat for HTLV and HIV, respectively), HIV virions contain considerably more surface and transmembrane envelope proteins than do HTLV virions. When subjected to high speed centrifugation almost all detectable viral RNA in HTLV or HIV conditioned, media is contained within a dense, precipatable particle (Table 2). HIV particle associated RNA can be gently immunoprecipitated with beads bound with either anti-gp120 env or anti-gp41 env antibodies indicating the presence of both proteins on the viral envelope. Only minimal immunoprecipitation of HTLV-I RNA was observed with beads bound with either anti-gp46 env or gp21 env antibodies indicating a relative paucity of these two proteins on the viral envelope. 1237 (0.08%) of the VBD samples were positive for HTLV antibodies when analyzed by EIA.
Of these, 105 (0.007%) were confirmed as true positives by WB and PCR (50 HTLV; 55 HTLV-II), while the remainder were deemed false positive. When examined by WB and RIPA, 170 (15%) of the false positives gave completely negative signals. 712 (63%) scored positive against p19gag only; 203 (7.9%) against p24 only; 18 (1.6%) both p19 gag and p24 gag; 22 (1.9%) against gp21 env only; 3 (0.3%) both p19 gag and gp21 env. Of the people at risk for HTLV infection, 350 (14%) were positive for HTLV antibodies when analyzed by EIA. Of these, 348 were confirmed as true positives (150 HTLV-I; 198 HTLV-II). Of these, 345 (99.1%) were DNA PCR positive and all were WB positive. However, an additional 11 HTLV-I and 73 HTLV-II EIA negative, PCR positive persons were identified. In the EIA negative PCR positive individuals, approximately one half made antibodies to either HTLV Tax, gp46env and/or gp21 env proteins. Epitope mapping of seroreactivities to HTLV linear and recombinant peptides using 20 each of select EIA true seronegative, true seropositive, falso seronegative, and false seropositive samples indicated that an optimal HTLV antigen prep would omit HTLV p19 gag, and include whole p24 gag and Tax, and recombinant gp46 and gp21 env peptides encoded by nucleic acids 5290–5829 and 6169–6390, respectively.
BMP4/Madh5 Dependent Signaling Is Required for the Expansion of a Population of Stress Erythroid Progenitors in the Fetal Liver.
Authors: Paulson Robert F. , Porayette Prashanth 
Published: April 2020

Abstract
Fetal liver hematopoiesis is primarily erythropoiesis, which robustly produces erythrocytes to meet the growing need of the developing embryo. In many ways fetal liver erythropoiesis resembles stress erythropoiesis in the adult, where in response to acute anemia, a unique population of stress erythroid progenitors is rapidly expanded in the spleen. The development of these stress progenitors requires BMP4/Madh5 dependent signals. Spleen stress progenitors exhibit properties that are distinct from bone marrow steady state progenitors in that they are able to rapidly form large BFU-E colonies, which require only Epo stimulation for their generation. Mice mutant at the flexed-tail locus exhibit a defective stress erythroid response because of a mutation in Madh5. In addition to this defect, flexed-tail mice also exhibit a severe fetal-neonatal anemia. We have analyzed fetal liver erythropoiesis in flexed-tail and control embryos. We show that BMP4 is expressed in the fetal liver and its expression correlates with the time of maximum erythropoiesis. In flexed-tail mutant embryos the expression is delayed and this correlates with both a delay and a defect in the expansion of erythroid progenitors. Our analysis also shows that the fetal liver contains two types of erythroid progenitors. One type exhibits the properties of stress BFU-E found in the adult spleen, which are compromised in flexed-tail embryos and a second type that is similar to bone marrow steady state BFU-E. These data demonstrate that BMP4 dependent signaling drives the expansion of erythroid progenitors in the fetal liver in a manner similar to stress erythropoiesis in the adult spleen.
Periodicity of Differentiation and Self-Renewal Suggest Homeostatic Feedback Control of Commitment in a Hematopoietic Progenitor Cell Line.
Authors: Cross Michael , McIvor Zoe , Labani Marion , Alt Ruediger , Niederwieser Dietger 
Published: April 2020

Abstract
FDCPmix cells are karyotypically normal, non-leukemic, murine multipotent progenitors which undergo extensive self-renewal in the presence of a high concentration of interleukin-3 (IL-3), and progressive commitment and differentiation along all myelo-erythroid lineages upon substitution with the appropriate cytokines. Although clonal, the FDCPmix cells are characterised by a variable degree of heterogeneity in the population. This heterogeneity is apparent firstly from the variable background of morphologically differentiated cells which accumulate in self-renewal (high IL-3) conditions, and secondly from the low and variable incidence of colony-forming cells (CFU) which are capable of extensive self-renewal in semi-solid media and which are generally assumed to be the founder cells of the population. In order to define the variability in more detail, early passage FDCPmix cells were thawed into standard culture conditions and passaged back to 6x104 cells per ml every 2 days over a period of nine months. The degree of background differentiation and the incidence of colony forming cells were determined at weekly intervals. Based on our unpublished observations that glucose concentration can influence progenitor cell fate, parallel cultures were maintained in IMDM (4g/L glucose) and DMEM (1g/L glucose) and all CFU assays were performed using both IMDM and DMEM based semi-solid media. In both IMDM and DMEM cultures, the level of background differentiation increased from 0 to an initial peak of 15% (IMDM) to 30%(DMEM) over the first 5 weeks, followed thereafter by further peaks at 3–4 week intervals. There was no corresponding pattern in the CFUIMDM frequency. However, a similar 3–4 week periodicity (displaced from that of the background differentiation) was evident in both the frequency of CFUDMEM and particularly in the ratio of CFUDMEM to CFUIMDM. The high frequency of CFUDMEM and the low frequency of differentiated cells over the first 5 weeks of culture corresponded to the period in which the FDCPmix cells underwent a homogenous and rapid differentiation in response to erythroid or myeloid growth factors. These patterns of periodicity in both IMDM and DMEM cultures are suggestive of a delayed feedback phenomenon in which the accumulation of differentiating cells causes a decrease in the ratio of commitment-to-self-renewal of the founder cells, and subsequent decrease in differentiating cell numbers, with the delay between commitment and differentiation being responsible for overshoot, and the relatively long periods of phasing observed. Since the cultures were diluted regularly into fresh media, the basis of such a feedback is likely to involve cell-cell contact rather than diffusible factors. In vivo, a local cell census taken in this way may represent a means of restricting the local concentration of stem cells in a given niche.
Stem Cell Aging Studies Reveal Changes in the Proteasome.
Authors: Miller Alison R. , Liang Ying , Van Zant Gary 
Published: April 2020

Abstract
To investigate aging mechanisms in murine hematopoietic stem cells (HSCs), a microarray analysis was performed on sorted Lin-cKit+ Sca-1+ cells of young and old mice of two strains: long-lived C57B6L/6 (B6) and short-lived DBA/2 (D2). Following analysis by two-way ANOVA with a FDR of 5%, the data was organized using gene ontology software. The following age-related transcriptional changes were found to be of significance: increases in 20S (α and β) and 26S proteasome subunits, ribosomal proteins, mitochondrial enzymatic proteins, and carbohydrate metabolism, and a decrease in ubiquitination proteins. In general, B6 changes were more dramatic than those of D2. These data are surprisingly consistent with well-established theories of aging in post-mitotic cells, most commonly neurons, where the function of the proteasome decreases while the number of proteasome subunits increases in a compensatory manner to maintain protein turnover. Eventually, the proteasome can become over-loaded and the lysosomal pathway must assume the load of additional protein degradation. It is common for protein aggregates, lysosomal dysfunction, and damaged mitochondria to be observed in neurons with inhibited proteasome function. Our data are consistent with the initial steps in this theory, but the later, dysfunctional consequences of proteasome inhibition have not yet been observed in HSCs. It is interesting that this pattern would be present in stem cells, since they are responsible for self-renewal and differentiation throughout the lifetime of the organism. It is possible that the lack of protein aggregates or dysfunctional mitochondria is actually due to dilution by cell division, especially considering that the proteasome is responsible for degradation of many cell cycle proteins and that genes involved in energy production were up regulated. Therefore, it is possible that HSCs show similar aging trends with regard to the proteasome but do not have the same cellular consequences as post-mitotic cells. It is also interesting that B6 and D2 showed the same aging trends but B6 appears better able to compensate for proteasome alterations. For example, B6 increases the beta catalytic subunits of the 20S proteasome core more so than its short-lived counterpart. Additionally, B6 are known to have more HSCs in old age than D2, which is consistent with more cells being able to either compensate for decreased proteasome function or to increase cell cycle to dilute out any deleterious effects of proteasome inhibition. These data suggest that HSCs share common aging trends with other cell types; however, they are able to maintain “healthy aging” more effectively than post-mitotic cells, especially in the case of B6. It is tempting to speculate that the longevity of D2 mice could be limited by its alterations in proteasome function and its decreased ability to compensate other cellular responses in order to maintain homeostasis.
Different Gene Expression Profiles of CD133+ Cells from Cord Blood and Mobilized Peripheral Blood.
Authors: Giorgetti Alessandra , Agnelli Luca , Mattioli Michela , Lombardi Luisa , Neri Antonino , Bicciato Silvio , Giordano Rosaria , Rebulla Paolo , Lazzari Lorenza 
Published: April 2020

Abstract
Cord blood (CB) is a valid alternative to mobilized peripheral blood (mPB) as a source of hematopoietic stem cells for clinical transplantation. The qualitative differences among CD133+ cells from these sources have been demonstrated by in vitro and in vivo studies but the molecular phenotype of these cells is only partially understood. In view of better exploiting the peculiarities and advantages of both stem cell sources, we performed a comparative analysis of gene expression of CD133+ cells from CB and mPB using Affymetrix HG-U133A arrays. The CD133+ cells were selected using the MiniMacs immunomagnetic separation system (Miltenyi Biotec) from 6 CB units and 6 mPB samples. Since microarray results are strictly dependent on the purity of the cell population and on the RNA quality, rigorous quality controls were applied. The purity of CD133+ cells was more than 93% in all samples. In addition, after extraction, the RNA was purified by the RNeasy system (Qiagen) and the RNA quality was evaluated using the RNA 6000 Nano LabChip kit (Agilent Technologies). Given the low amount of RNA due to the limited numbers of CB CD133+ cells, we used a double-cycle amplification protocol for both sources to obtain biotin-labeled target for hybridization starting from as low as 100 ng of total RNA. Probe level data have been converted to expression values using Affymetrix MAS 5.0 algorithm. Differentially expressed genes have been identified using Significance Analysis of Microarrays (SAM). The cut-off for significance has been determined tuning the Delta parameter on the false positive rate and controlling the q-value for the gene list. We found that mPB CD133+ cells expressed cell cycle driving, transcription factor and DNA synthesis genes at distinctly higher levels than CB CD133+ cells, indicating a higher cycling activity in mPB CD133+ cells. Furthermore apoptosis driving genes were up-regulated in mPB CD133+ cells, probably due to G-CSF mobilization. Conversely in CB CD133+ cells we found an overexpression of genes involved in immunoresponse and immunomodulation. This finding could justify the peculiar immunological properties of CB. Finally, many genes related to different metabolic pathways such as alcohol, sterol, nucleotide, lipid and sugar biosynthesis, were found up-regulated in CB CD133+ cells, maybe due to the neonatal origin of these cells. In conclusion, mPB CD133+ cells include a more committed and cycling population while CB CD133+ represent a cell subset with higher potentialities probably due to their immaturity. This suggest that even if CB has a lower number of stem cells, CB CD133+ cells are more susceptible to different stimuli and potential fates.
Therapeutic Angiogenesis in Critical Limb Ischemia by Implantation of Autologous Hematopoietic Cells.
Authors: Besalduch Juan , Lara Raul , Sampol Antonia , Gutierrez Antonio , Lozano Pacual , Galmes Antonio 
Published: April 2020

Abstract
Patients with critical limb ischemia in whom surgical repair is not possible because bad distal vasculature, have an ominous prognosis. This study describes a technique for treatment of patients with critical limb ischemia with implantation of autologous peripheral mobilized hematopoietic cells, with the aim to stimulate angiogenesis.
Twelve patients (9M, 3F), with a median age of 58 years (22–78) with critical limb ischemia were treated by injections of peripheral mobilized blood cells in the gastrocnemius muscle of the affected limb. The inclusion criteria were patients with chronic limb ischemia grade III-IV by Doppler examination, plethismography and angiography, with failure to respond to non-surgical treatment and some with previous surgery, and that were no candidates for surgical revascularization. The patients were treated by G-CSF (Neupogen, Amgen) 5μ /kg weight/d during 5 days. At day fifth and sixth we obtained peripheral mononuclear blood cells by means of a CS-3000 Plus (Baxter) blood cell separator. The unmanipulated cells were injected in the affected limb in 2 ml aliquots into the gastrocnemius muscle. Each product of a single apheresis (volume 50 ml) were injected in a sole limb. Six patients received injections only in one limb. Each patient were evaluated regularly for rest pain, amount of required analgesia, healing of the ulcers, peak walking time and, Doppler, plethismographic and angiographic findings. The mean number of injected CD34+ cells in each limb was 0.77 x 106/kg. There were no secondary effects for the mobilization and injection of cells in the 12 studied patients. Moreover, in 7 patients studied with a median follow-up of 1 year, 5 showed an improvement of all parameters, specially pain at rest, peak walking time and skin throphic lesions. Two patients suffered early amputation of the affected extremity because obstruction of an old by-pass.
Despite the short follow-up and small patient series, this technique is expected to achieve relief of pain and decrease in major amputations in this critical population. However, comparative studies with longer follow-up should be done to confirm the benefits of this technique.