bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Prediction of Acute Leukemia Relapse after Allogeneic SCT by Chimerism Analysis of Null Alleles and Indel Polymorphisms with Real-Time Quantitative PCR.
Authors: Jimenez-Velasco Antonio , Barrios Manuel , Roman-Gomez Jose , Navarro German , Buño Ismael , Diez-Martin Jose L. , Torres Antonio , Heiniger Ana I. 
Published: October 2019

Abstract
Increasing mixed chimerism (MC) predicts morphological relapse after stem cell transplantation (SCT) in patients with acute leukemia. Early treatment of increasing MC reduces the onset of relapse and improves survival. However, conventional methods for chimerism analysis fail to detect MC prior to a considerable number of relapses. We have tested a new approach for chimerism follow-up, based on amplification by real-time quantitative PCR (rtq-PCR) of null alleles and insertion/deletion (indel) polymorphisms, and compared it with conventional variable number of tandem repeats (VNTR)-PCR. Four null alleles: GSTM1, GSTT1, RhD and SRY, and 10 indels: Xq28, rs4399, DCP1, R271, FVII, THYR, MID-1039, MID-1335, MID-1385, MID-2062, were quantified by rtq-PCR using allele-specific primers and probes (LyghtCycler technology). Sensitivity studies (by mixture of positive and negative DNA), and intra- or inter-assay variability experiments were performed. All markers showed high sensitivity (at least 0.01%) and reproducibility. Accuracy of the method was also confirmed by dilution of positive in negative cells with subsequent DNA extraction and rtq-PCR quantification. Donor/host informativity (presence of the sequence in the recipient and absence in the donor) was tested retrospectively in a series of 68 acute leukemia patients, and at least one informative marker was obtained in 85.3% of donor/host pairs. Chimerism follow-up was performed on peripheral blood (PB) and bone marrow (BM) samples obtained after SCT. In non-relapsed patients, PB host chimerism values progressively descended from transplantation until reaching donor complete chimerism (CC); conversely, BM chimerism decreased but did not reach CC more than 3 years after SCT. From 18 relapses evaluable with rtq-PCR, 16 (89%) showed increasing chimerism in PB samples prior to relapse; by contrast, only 73% of such relapses were preceded by increasing MC in BM. When compared to VNTR, rtq-PCR predicted a significantly higher number of relapses (89% vs 42%) and anticipated them earlier (median of 56 vs 38 days). In summary, rtq-PCR determination of null alleles and indels constitutes a new validated simple procedure to monitor hematopoietic chimerism after SCT. It improves the predictive results obtained with conventional VNTR-PCR, and is specially useful when PB samples are analyzed.
Results of Bortezomib (BTZ) Therapy for Myeloma (MM) Patients Relapsing after an Allogeneic Transplant. Preliminary Results Show Efficacy without Induction of GVHD.
Authors: Giralt Sergio , Aleman Ana , Lei Xin , Davis Marilyn , Mickler Kerry , Weber Donna , Wang Michael , Champlin Richard 
Published: October 2019

Abstract
Background: The proteosome inhibitor bortezomib (BTZ) has demonstrated significant activity against multiple myeloma (MM). In vitro data suggests that protesome inhibition has immune-modulatory activity that may be relevant in the setting of allogeneic progenitor cell transplantation (allo SCT). However, there is limited experience with the use of BTZ in patients with MM relapsing after an allo SCT.
Purpose: Determine safety, efficacy and effects on GVHD of BTZ in MM patients relapsing after an allo SCT.
Methods: Retrospective analysis of outcomes on 9 MM patients who received BTZ therapy for MM relapse after allo SCT
Results: Nine patients were identified. Median age was 51 (range, 38–64); all patients underwent an allo SCT because of failure to respond or relapse after primary therapy including autograft in 8 patients. At the time of allo SCT; 3 patients had refractory disease and 6 had chemo-sensitive relapses. The median time from allo SCT to relapse was 8.5 months (range, 5–117); the median time from relapse to initiation of BTZ therapy was 3.4 months (range, 0.1–20). BTZ was the 1st line of therapy for relapse in 5 patients. No patient had active GVHD at the time of BTZ therapy. BTZ was given at a dose of 1.3 mg/m2 on days 1,4,8 and 11 every 21–28 days for a median of 3 cycles (range, 2–8). 4 patients received BTZ alone, 3 in combination with DEXA, and 2 in combination with DEXA/THAL. 6 of 9 patients had either a 50% reduction or greater of monoclonal peak, of which 2 were very good PR (>90% reduction) to BTZ. BTZ was well tolerated and no flares of GVHD were seen. Only 2 patients developed severe thrombocytopenia and fatigue, which required discontinuation of therapy (one in the context of relapsing disease). 2 of the responding patients have relapsed at 4 and 7 months after initiation of BTZ therapy. 4 of the 6 responses are ongoing 3 to 9 months after initiation of BTZ therapy. Individual patient outcomes are summarized in Table 1.
Conclusions: BTZ therapy is effective as treatment of MM relapse post allo SCT, it is well tolerated and does not promote GVHD reactions. The response rates would seem to be higher than the responses reported to donor lymphocyte infusions in this setting. BTZ therapy should be studied as front-line therapy for patients relapsing after allo SCT and as maintenance therapy post high risk allograft.
Individual Patient Outcomes
Pt# #Cycles BTZ BTZ plus Response Duration of Response NCI Toxicity 3-4-5 Outcome 1 3 Dexa PR Ongoing None Alive PR 3+m 2 2 - PR 4m Fatigue 3/Heme 4 Died PD 5m 3 2 Dexa PR Ongoing Fatigue 3/Heme 4 Alive PR 9+m 4 2 - PD 0 Diarrhea Alive PD 2+m 5 8 - VGPR Ongoing Alive VGPR 5+m 6 8 Dexa VGPR Ongoing Alive VGPR 6+m 7 3 - PD 0 Hypotension 3 Died PD 5m 8 4 Dexa/Thal PR 7m Alive PD 7+m 9 3 Dexa/Thal PD 0 Alive PD 4+m
Arginase Activity Is a Determinant of Nitric Oxide Levels in Adult Vasoocclusive Sickle Cell Crisis.
Authors: Lopez Bernard L. , Telem Dana , Flenders Pamela , Ma Xin L. , Ballas Samir K. 
Published: October 2019

Abstract
A number of studies have demonstrated both low nitric oxide (NO) and l-arginine (l-arg, the substrate for NO synthesis) levels during adult sickle cell vasoocclusive crisis (VOC). L-arg levels, while diminished, are 10-fold higher than the km (3 mM) of endothelial NO synthase (eNOS) and more than sufficient to saturate this enzyme (a state known as the arginine paradox). Diminished l-arg thus cannot directly explain lower NO levels. Two explanations, enhanced arginase activity (catalyzing the conversion of l-arg to ornithine), and inhibition of NOS by increased levels of asymmetric dimethylarginine (ADMA) have been proposed to explain this arginine paradox in VOC. We sought to investigate these mechanisms during adult VOC in the emergency department (ED). L-arg, ornithine, and citrulline (the end product of ADMA metabolism) were measured via ion exchange chromatography from blood obtained from adult ED VOC patients. Citrulline levels were used as an indirect indicator of ADMA and ornithine levels were used as an indicator of arginase activity. Samples from sickle patients in steady-state and from normal healthy volunteers were obtained for comparison. As expected, VOC subjects had significantly lower median l-arg levels (23.16 μM/l, 18.74–29.81 IQR, p<0.001 vs steady state, 38.56 μM/l, 5.88–20.26 IQR, and control, 73.01 μM/l, 27.42–37.2 IQR). There was no significant difference in citrulline levels. Ornithine, the end product of l-arg metabolism by arginase, was lower in VOC (median: 22.61 μM/l, 17.22–27.3 IQR, p<0.001 vs steady state median of 36.78 μM/l, 30.28–42.26 IQR). It has been suggested that the l-arg:ornithine ratio may be a better reflection of total arginase activity - in this study, the l-arg:ornithine ratio was significantly lower in adult VOC (1.02 vs 2.71) when compared to healthy controls, indicating enhanced total arginase activity. We conclude that the l-arg-arginase-ornithine pathway may play a significant role in the diminished NO seen in adult VOC patients via enhanced arginase activity. This enhanced arginase activity may alter available l-arg, resulting in decreased NO. ADMA does not appear to be an important contributor to the arginine paradox found in adult VOC.
Is Screening for Microalbuminuria Warranted in Children with Sickle Cell Hemoglobinopathies?.
Authors: Alvarez Ofelia , Montane Brenda 
Published: October 2019

Abstract
Renal impairment occurs in adults and children with sickle cell disease. Microalbuminuria (MA) defined as albumin excretion >2.9 mg/dl in random urine sample or 30–300 mg in 24 hour urine collection is an early, sensitive indicator for glomerulopathy in both diabetes mellitus and sickle cell disease. Therefore, we conducted a universal screening in our patients (pts) with sickle cell hemoglobinopathies in order to identify the prevalence of MA and other indicators of early renal impairment. Children and young adults with hemoglobin SS, SC, Sβ+thalassemia and Sβ0thalassemia, ages 4–21 years (yrs), had urinalyses and random urine measurements for protein, microalbumin, and creatinine. All were in good state of health, free of pain, and without prior diagnosis of renal dysfunction when the samples were obtained. Serum electrolytes, creatinine, osmolality, and 24-hour urine collection for protein, microalbumin, β2-microglobulin, creatinine, and electrolytes were done in pts with abnormal urine samples. There were 101screened pts (53 males; 76 SS, 20 SC, 3Sβ0, and 2 Sβ +). Nineteen pts had MA detected by random urine. MA was confirmed in 24-hour samples in 46% of studied pts. In addition to MA, tubular proteinuria (increased β2-microglobulin) was detected in 1 pt, isolated hematuria in 3 and increased urine protein/creatinine (>0.2) in 4. From the MA+ pts, 15 had SS (19.7% of SS group) and 4 had SC (20% SC group). 25% of children 10 yrs of age or older had MA (mean± standard deviation MA 2.83±3.94), as compared to 6% of younger children (mean 1.21±0.80), (p=0.02). African Americans had lower incidence of MA (11.4%), compared to other children of Haitian (21.3%), Hispanic Caribbean (25%), and other Caribbean (28.5%) descent (p=not significant [NS]). There was no correlation between MA and history of stroke, acute chest syndrome/asthma, brief use of non-steroidal anti-inflammatory medications, hemoglobin or white cell values. From the subgroup of 16 pts on hydroxyurea, 11 were 10 yrs of age or older; of these, 5 (45.5%) had MA, compared to 21% of the same age non-treated group (p=NS). We analyzed the effect of age at onset of chronic transfusions and presence of MA. Six transfused pts had MA (age at start of transfusion 8.6–13.5 yrs, mean 11 yrs; mean MA 5.3±3.4), while there were 15 MA free pts (age 0.8–12.4 yrs, mean 7 yrs; mean MA 1.4±0.6), suggesting that early age at start of chronic transfusions may be protective for MA (p=0.0004). We conclude that: (1) urine screening of children with sickle cell hemoglobinopathies 10 yrs or older is recommended, (2) chronic transfusions starting at an early age may protect against MA, and (3) validity of random versus 24-hour urine collections in determining MA should be further investigated. Studies to further define the risk factors, prognosis, and intervention in children with sickle cell hemoglobinopathies are warranted.
Cerebral Oxygen Saturation in Sickle Cell Patients Treated with Hydroxyurea:.
Authors: Nahavandi Masoud , Tavakkoli Fatemeh , Wyche Melville Q. , Hasan Syed P. , Castro Oswaldo 
Published: October 2019

Abstract
Recently we reported the use of a non-invasive near-infrared optical spectroscopy technique to measure cerebral oxygenation (cerebral oximetry, rSO2%) in agroup of 27 adult patients with sickle cell disease (Eur J Clin Invest, 34:143,2004). The sickle cell patients’ rSO2 values were significantly lower (mean 47.7%) than those in normal subjects (mean 61.3%) even though none of the patients had clinical evidence of stroke or cerebral ischemia. We included patients with all Hb phenotypes, and regardless of hydroxyurea (HU) treatment. Transfusions improved cerebral oxygen saturation but the post-transfusion values still did not reach normal levels. Our findings were corroborated independently by Raj et al. who studied 25 children with sickle cell disease (J Pediat Hematol Oncol 26:279,2004). In order to determine if long-term HU treatment affects rSO2, we analyzed cerebral oximetry results in a subset of 31 patients with sickle cell anemia (Hb SS). Eleven of them were on long-term (more than 6 months) HU treatment at stable doses (1000–1500 mg/day). The table shows that the mean rSO2, Hb, Hct, and MCV in HU-treated patients were significantly higher than those in sickle cell anemia (SCA) patients not on HU. The rSO2 in HU-treated patients was 12.5% higher than in SS patients not on this drug. By comparison, we previously reported a 24% increment in rSO2 following transfusions.
A group of 8 patients who were on long-term HU treatment were given also single 1000 mg oral doses of HU and their rSO2 was measured for 12 hours without noticeable change in cerebral oxygenation. Nor did rSO2 change after oxygen inhalation (3L/min). The cause of the low rSO2 in sickle cell patients is unknown and still under investigation. It is probably not related exclusively to the anemia, since, as previously reported, anemic subjects without sickle cell disease appear to have normal rSO2. These preliminary results indicate that chronic HU treatment is associated with higher rSO2 values in SCA. If validated in a larger number of patients, our findings suggest that cerebral oximetry could be a useful, non-invasive method for assessing a new in vivo effect of HU and red cell transfusion in sickle cell disease: increased blood oxygen saturation in the cerebral vasculature.
HYDROXYUREA AND CEREBRAL OXYGEN SATURATION IN PATIENTS WITH SICKLE CELL DISEASE
NO HYDROXYUREA (N=20) HYDROXYUREA (N=11) P value* rSO2 = cerebral oxygen saturation. *= t-test. Plus/minus figures represent SD Mean rSO2 (%) 41 ± 6.6 46 ± 7.6 0.025 Mean Hb (g/dl) 8.4 ± 1.4 9.68 ± 1.2 0.029 Mean Hct (%) 24± 3.4 28± 4.4 0.027 Mean MCV (fl) 89± 8 102± 7 0.028
The Genetic and Phenotypic Diversity of Dyskeratosis Congenita.
Authors: Vulliamy Thomas J. , Marrone Anna , Walne Amanda , Stevens David , Mason Philip J. , Dokal Inderjeet S. 
Published: October 2019

Abstract
Two of the genes responsible for the bone marrow failure syndrome dyskeratosis congenita (DC) have been identified. These have evoked considerable interest as the products of both of these genes are involved in the telomerase complex. Telomerase is responsible for maintaining telomere length at the ends of each chromosome and hence the replicative potential of stem cells and cells in the germ line. In order to define the heterogeneity of DC, we have reviewed the clinical features and genetic basis of 213 families that have been referred to the DC registry at the Hammersmith Hospital. In 67 families we have identified 34 different mutations in the gene that encodes the protein dyskerin (DKC1), 9 of which are unpublished (P10L, T67I, H68Q, K314R, D359N, A386T, T408I, S420Y and IVS14nt473A->G). While most of these mutations are unique, the remarkably frequent A353V substitution is seen in 28 different families. Presentation of cases with this amino acid substitution ranges from a very severe disease, causing death at the age of 4 years, to a man who is alive into his 40s. In 10 families we have found mutations in the gene encoding the RNA component of telomerase (TERC), all of which are unique. Presentation of these heterozygous TERC mutations is even more variable, ranging from an asymptomatic 80 year old woman, to a girl presenting with hypoplastic MDS at the age of 3. In a substantial proportion of families (40/213) the index case presents with very severe disease, previously defined as the Hoyeraal-Hreidersson (HH) syndrome (characterized by growth retardation, microcephaly, cerebellar hypoplasia, and the development of bone marrow failure/immunodeficiency usually below the age of 5 yrs). In 28 of these families there is affected male(s) only, 13 of which have DKC1 mutations. Of these, 4 have the same amino acid substitution (T49M), which is only seen in patients with HH. In the 12 HH families with affected females, none have DKC1 mutations, 6 are sporadic and 6 appear to have an autosomal recessive form of inheritance. In a large number of families we have been unable to find either a DKC1 or TERC mutation. This includes not only the majority (51/60) of the families in which there is an affected female, but also nearly two thirds (77/113) of the sporadic male cases. Other important gene(s), possibly related to the telomerase complex, are therefore yet to be identified.
Prothrombin Residues 473 to 487 Contribute To Factor Va Binding in the Prothrombinase Complex.
Authors: Yegneswaran Subramanian , Mesters Rolf M. , Fernandez Jose A. , Griffin John H. 
Published: October 2019

Abstract
To identify sequences in prothrombin (fII) involved in assembly of the prothrombinase complex (fXa:factor Va:fII:phospholipids), synthetic peptides based on fII sequences were prepared and screened for their ability to inhibit fXa-induced clotting of normal plasma. The fII peptide comprising residues 473–487 (designated PT473–487 that are homologous to chymotrypsin residues 149D-163) potently inhibited plasma clotting assays and prothrombinase activity with 50% inhibition observed at 12 microM and 10 microM peptide, respectively. Prothrombinase inhibition by PT473–487 was fVa-dependent and sequence-specific since the peptide did not inhibit fII activation in the absence of fVa and a scrambled sequence peptide, PT473–487SCR, was not inhibitory. Peptide PT473–487 also inhibited cleavage at Arg271 in meizo-thrombin, showing that it similarly inhibited fXa cleavage at both Arg320 and Arg271. Peptide PT473–487 did not inhibit the amidolytic activities of fXa or thrombin, suggesting that the peptide did not alter the integrity of their active sites. To determine if PT473–487 interacted directly with fVa, fluorescein labeled-fVa (Fl-fVa) was prepared. When PT473–487 was titrated into samples containing phospholipid-bound Fl-fVa, the peptide increased fluorescein anisotropy (EC50 at 3 microM peptide) whereas the control peptide PT473–487SCR peptide did not alter the anisotropy, suggesting a direct binding interaction between PT473–487 and Fl-fVa. These functional and spectroscopic data suggest that fII residues 473–487 provide fVa binding sites and mediate interactions between fVa and fII in the prothrombinase complex that contribute to cleavages at both Arg271 and Arg320 by fXa.
The Regulation of Factor IXa by Phosphatidylserine.
Authors: Majumder Rinku , Monroe Dougald M. , Cole Daud , Lentz Barry R. 
Published: October 2019

Abstract
A number of clinical studies have demonstrated correlation between elevated levels of factor IX and the risk of coronary heart disease. Studies by different groups have shown that blocking procoagulant activity of factor IXa could reduce the risk of thrombosis. We propose to study the regulation of factor IXa by phosphatidylserine (PS) which further could open up possibilities to design drugs that might inhibit the up regulation of the procoagulant protein factor IXa. The activated form of factor IX, IXa, forms the Xase complex together with factor VIIIa and Ca2+ on an activated platelet membrane surface. We hypothesize that PS regulates factor IXa by binding to specific sites on factor IXa and thereby enhancing its catalytic activity. We used a soluble form of phosphatidylserine, 1,2-dicaproyl-sn-glycero-3-phospho-L-serine (C6PS) as a tool in order to address the role of PS in regulating factor IXa. Intrinsic fluorescence measurements demonstrate that C6PS binds tightly (Kd ~1.3 μM) to and induces changes in conformation of factor IXa. We also monitored the amidolytic activity of 300 nM factor IXa in the presence of C6PS using synthetic substrate Leu-PHG-Arg-pNA. There is a reduction in the amidolytic activity of factor IXa with increasing addition of C6PS and the hyperbolic fit gives an apparent Kd of 130 μM. Recent results show that calcium is required for both amidolytic and proteolytic activity of factor IXa in the presence of C6PS. Our data shows that amidolytic activity of factor IXa in the presence of 600 mM C6PS is saturated at a concentration of calcium near 3 mM. We have also demonstrated that both C6PS and calcium enhance proteolytic activation of factor X by factor IXa. The data shows that as the concentration of Ca2+ increases, the proteolytic activation of factor X by factor IXa increases as well. Enhancement of factor X activation appears to saturate at a calcium concentration of 3 mM. Based on these results, we conclude, 1) C6PS induces a conformational change in factor IXa, 2) C6PS regulates the amidolytic and proteolytic activity of factor IXa, 3) Ca2+ is needed for PS mediated regulation of factor IXa.
Antibody to C1 Domain of Factor VIII Alters Interaction of Factor Xase Complex with Factor X.
Authors: Gilbert Gary E. , Bhimavarapu Anu , Price Patricia , Jacquemin Marc 
Published: October 2019

Abstract
The role of the C1 domain in function of factor VIII has not been clearly defined. In contrast, functional interactions have been identified for the three A domains and the C2 domain. We hypothesized that the C1 domain of factor VIII participates in both phospholipid binding and interaction with factor X and/or factor IXa. We evaluated inhibition of the factor Xase complex by LE2E9, a human inhibitor IgG4k mAb against C1. We utilized altered catalytic activity of the factor Xase complex in a defined assay to report the inhibition by LE2E9. Inhibition by LE2E9 was also evaluated when soluble phosphatidylserine replaced vesicles to support the factor Xase complex and when Gla-domainless factor X was the substrate. The deglycosylated form of LE2E9 was also evaluated to better define the mechanism through which LE2E9 exerts its effect. We found that LE2E9 bound to factor VIIIa with an apparent KD of 0.5 nM. The apparent affinity of factor VIIIa for sonicated phospholipid vesicles of phosphatidylserine:phosphatidylethanolamine:phosphatidylcholine 4:20:76 increased 3-fold in the presence of LE2E9. The apparent affinity of factor VIIIa for factor IXa was not significantly changed. The KM of the factor VIIIa-factor IXa complex was 20 ± 2 nM with LE2E9 vs. 40 ± 2 nM without. LE2E9 decreased the Vmax by 77 ± 6% indicating that the affinity of factor X for the factor Xase complex is increased while the rate of cleavage is decreased. When Gla-domainless factor X was used as the substrate for the factor Xase complex, LE2E9 did not inhibit activity indicating that inhibition occurs via an interaction that involves the factor X Gla domain. When the factor VIIIa-factor IX complex was supported by dihexanoyl phosphatidylserine rather than phospholipid vesicles the inhibition of Vmax was 47% indicating that the inhibitory effect does not require a phospholipid bilayer. Deglycosylated LE2E9 did not significantly change the KM but decreased the Vmax by 22% while both antibodies bound to factor VIII with the same affinity. These results suggest that LE2E9 inhibition relates largely to interaction of a carbohydrate moiety with factor VIII or factor X rather than binding the core C1 epitope. We conclude that LE2E9 decreases the KM, and the Vmax for the factor VIIIa-factor IXa complex, but only when the factor X Gla domain is present. These results suggest that in the factor Xase complex the C1 domain of factor VIII is intimately associated with the Gla domain of factor X and that interaction between these domains enhances the kcat for the factor VIIIa-factor IXa complex.