A magnetar-powered X-ray transient as the aftermath of a binary neutron-star merger.

Mergers of neutron stars are known to be associated with short γ-ray bursts1-4. If the neutron-star equation of state is sufficiently stiff (that is, the pressure increases sharply as the density increases), at least some such mergers will leave behind a supramassive or even a stable neutron star that spins rapidly with a strong magnetic field5-8 (that is, a magnetar). Such a magnetar signature may have been observed in the form of the X-ray plateau that follows up to half of observed short γ-ray bursts9,10. However, it has been expected that some X-ray transients powered by binary neutron-star mergers may not be associated with a short γ-ray burst11,12. A fast X-ray transient (CDF-S XT1) was recently found to be associated with a faint host galaxy, the redshift of which is unknown13. Its X-ray and host-galaxy properties allow several possible explanations including a short γ-ray burst seen off-axis, a low-luminosity γ-ray burst at high redshift, or a tidal disruption event involving an intermediate-mass black hole and a white dwarf13. Here we report a second X-ray transient, CDF-S XT2, that is associated with a galaxy at redshift z = 0.738 (ref. 14). The measured light curve is fully consistent with the X-ray transient being powered by a millisecond magnetar. More intriguingly, CDF-S XT2 lies in the outskirts of its star-forming host galaxy with a moderate offset from the galaxy centre, as short γ-ray bursts often do15,16. The estimated event-rate density of similar X-ray transients, when corrected to the local value, is consistent with the event-rate density of binary neutron-star mergers that is robustly inferred from the detection of the gravitational-wave event GW170817.

Multiplex fluorescence in situ hybridization in identifying chromosome involvement of complex karyotypes in de novo myelodysplastic syndromes and acute myeloid leukemia.

Complex chromosomal aberrations (CCA) can be detected in a substantial proportion of myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML), which are associated with very poor prognosis. Conventional cytogenetics (CC) cannot accurately define the specific alterations in CCA. Multiplex fluorescence in situ hybridization (M-FISH) allows the comprehensive identification of CCA. In this study, M-FISH was used in 16 patients with de novo MDS and 22 with AML with CCA detected by R-banding CC, and revealed 206 aberrations involved all 24 chromosomes, including 73 numerical chromosomal abnormalities and 133 structural abnormalities. The chromosomes most often involved were, by decreasing incidence, 5, 17, 8, 11, 7 and 21 in 57.9%, 55.3%, 44.7%, 36.8%, 34.2% and 34.2% of the cases, respectively. There were 98 unbalanced translocations, which were the most frequently observed aberrations in our study. Derivative chromosome 5 and 8 were implicated most often. The other derivatives were der(11), der(12), der(7), der(14), der(15) and der(17). Fourteen balanced translocations were detected in our series, and the most frequent reciprocal translocations was t(8;21). Fifty-five monosomies, 15 partial deletions, and 18 trisomies were found in all patients. The most frequently observed were -5/5q-, -17/17q-, -7, -18, -21, -19, and trisomy of chromosome 8 and 6. There were some abnormalities that have not been previously described, including two complex t(8;21) and seven unbalanced translocations. M-FISH could refine CCA, find or correct the missed or misidentified aberrations by CC analysis. Our findings confirmed that M-FISH was a powerful molecular cytogenetic tool to characterize complex karyotypes in MDS and AML.

AAV9-mediated erythropoietin gene delivery into the brain protects nigral dopaminergic neurons in a rat model of Parkinson's disease.

We have recently shown that intrastriatal injection of recombinant human erythropoietin (EPO) protects dopaminergic (DA) neurons in the substantia nigra (SN) from 6-hydroxydopamine (6-OHDA) toxicity in a rat model of Parkinson's disease. However, systemic administration of EPO did not protect nigral DA neurons, suggesting that the blood-brain barrier limits the passage of EPO protein into the brain. In the present study, we used an adeno-associated viral (AAV) serotype 9 (AAV9) vector to deliver the human EPO gene into the brain of 6-OHDA-lesioned rats. We observed that expression of the human EPO gene was robust and stable in the striatum and the SN for up to 10 weeks. EPO-immunoreactive (IR) cells were widespread throughout the injected striatum, and EPO-IR neurons and fibers were also found in the ipsilateral SN. Enzyme-linked immunosorbent assay and western blot analyses exhibited dramatic levels of EPO protein in the injected striatum. As a result, nigral DA neurons were protected against 6-OHDA-induced toxicity. Amphetamine-induced rotational asymmetry and spontaneous forelimb use asymmetry were both attenuated. Interestingly, we also observed that intrastriatal injection of AAV9-EPO vectors led to increased numbers of red blood cells in peripheral blood. This highlights the importance of using an inducible gene delivery system for EPO gene delivery.

Quantitative assay for Janus kinase 2 (JAK2) mutation in Chinese patients with chronic myeloproliferative disorders.

The Janus kinase 2 (JAK2) V617F mutation has considerably helped understanding of the molecular pathogenesis of chronic myeloproliferative disorders (MPD), hence this study investigated for the first time the mutational status and relative quantitation of JAK2 V617F mRNA in Chinese patients with chronic MPD. The study cohort comprised 123 chronic MPD patients (35 with polycythaemia vera [PV], 85 with essential thrombocythaemia [ET], three with idiopathic myelofibrosis [IMF]). Blood samples examined by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) and capillary electrophoresis showed that the prevalence of the JAK2 V617F mutation was 100%, 62.4% and 66.7% in PV, ET and IMF patients, respectively. The proportion of JAK2 V617F mutated mRNA was 89.5% in homozygotes and 57.9% in heterozygotes; 18 PV heterozygous patients showed significantly higher mutated JAK2 mRNA levels than 36 heterozygous ET patients. Six of 93 patients exhibited abnormal karyotypes, but specific chromosomal abnormality was not found. The combination of ARMS-PCR and capillary electrophoresis enables quantitative assay of JAK2 V617F mutation, which helps in chronic MPD diagnosis and estimation of minimal residual disease.

A new fusion gene NUP98-IQCG identified in an acute T-lymphoid/myeloid leukemia with a t(3;11)(q29q13;p15)del(3)(q29) translocation.

NUP98 has been involved in multiple recurrent chromosome rearrangements in leukemia. We identified a novel fusion between NUP98 and IQ motif containing G (IQCG) gene from a de novo acute T-lymphoid/myeloid leukemia harboring t(3;11)(q29q13;p15)del(3)(q29). IQCG has two putative coiled-coil domains and one IQ domain. The FG repeat from NUP98 and the coiled-coil domain from IQCG were retained in the fusion protein. We demonstrated that NUP98-IQCG could form homodimer, heterodimerize with NUP98 or IQCG, bind co-activators and/or co-repressors, and show transcriptional activity in vitro. Expression of NUP98-IQCG inhibited 32Dcl3 cell apoptosis induced by Ara-C, and partially blocked granulocyte differentiation induced by G-CSF. Colony-forming assay and serial replating assays indicated that NUP98-IQCG was able to stimulate proliferation, partially block differentiation of hematopoietic stem/progenitor cells but was unable to confer transformation alone. Taken together, our data indicate that newly identified NUP98-IQCG fusion protein may play an essential role in leukemogenesis, but by itself may not be sufficient to induce leukemia.

Intrastriatal administration of erythropoietin protects dopaminergic neurons and improves neurobehavioral outcome in a rat model of Parkinson's disease.

Erythropoietin (EPO), a hematopoietic cytokine, has recently been demonstrated to protect nigral dopaminergic neurons in a mouse model of Parkinson's disease (PD). In the present study, we tested the hypothesis that recombinant human erythropoietin (rhEPO) could protect dopaminergic neurons and improve neurobehavioral outcome in a rat model of PD. rhEPO (20 units in 2 microl of vehicle) was stereotaxically injected into one side of the striatum. 6-hydroxydopamine (6-OHDA) was injected into the same side 1 day later. Another group of rats received rhEPO (5000 u/kg, i.p.) daily for 8 days, and unilateral injection of 6-OHDA in the striatum 3 days after systemic administration of rhEPO. We observed that intrastriatal administration, but not systemic administration of rhEPO significantly reduced the degree of rotational asymmetry. The rhEPO-treated rats also showed an improvement in skilled forelimb use when compared with control rats. The number of tyrosine hydroxylase (TH)-immunoreactive (IR) neurons in the ipsilateral substantia nigra (SN) was significantly larger in intrastriatal rhEPO-treated rats than that in control rats. TH-IR fibers in the 6-OHDA-lesioned striatum were also increased in the intrastriatal rhEPO-treated rats when compared with control rats. In addition, there were lower levels of expression of major histocompatibility complex (MHC) class II antigens and a smaller number of activated microglia in the ipsilateral SN in intrastriatal rhEPO-treated rats than that in control rats at 2 weeks, suggesting that intrastriatal injection of rhEPO attenuated 6-OHDA-induced inflammation in the ipsilateral SN. Our results suggest that intrastriatal administration of rhEPO can protect nigral dopaminergic neurons from cell death induced by 6-OHDA and improve neurobehavioral outcome in a rat model of PD. Anti-inflammation may be one of mechanisms responsible for rhEPO neuroprotection.

Conventional and molecular cytogenetic features of myelodysplastic syndrome in China.

BACKGROUND: Myelodysplastic syndrome (MDS) constitutes a heterogeneous group of hematopoietic stem cell disorder characterized by peripheral blood cytopenia(s), in the presence of hypercellular bone marrow with features of ineffective hematopoiesis, and susceptibility to acute leukemia (AL). Although the precise pathogenesis of MDS remains to be clarified, cytogenetic abnormalities seem to be involved in its pathogenesis and are considered as an important factor in diagnosis and predicting clinical outcome. OBJECTIVE: To explore the cytogenetic features of Chinese patients with myelodysplastic syndrome (MDS). METHODS: Conventional cytogenetic analysis was performed in 88 MDS patients and among them, 34 cases were studied by interphase fluorescence in situ hybridization (I-FISH) with precisely chromosome 8 centromere specific DNA probe and DNA specific probes for 7q32 , 5q31. RESULTS: Of the 88 patients, 45 (51.1%) showed clonal karyotypic abnormalities by CC at diagnosis, including numerical changes (18 cases, 20.5%), structural changes (12 cases, 13.6%), and numerical and structural changes simultaneously(15 cases, 17.0%). Trisomy 8, -5/5q-, and -7/ 7q- account for 20.5%, 15.9%, and 5.7% respectively. Complex karyotypes were observed in 17 patients, the incidence being 19.3% in the whole series of cases. Among 34 MDS patients studied by I-FISH, -5/5q-, -7/7q- and trisomy 8 occurring in 4, 2 and 10 cases respectively for CC were confirmed by I-FISH. 5 cases in 30 cases who did not show -5/5q- by CC displayed this abnormality by I-FISH. 3 cases without -7/7q- by CC presented this aberration by I-FISH. 5 cases with trisomy 8 for I-FISH was not identified this change by CC. CONCLUSIONS: The frequent abnormalities are trisomy 8, -5/5q- and -7/ 7q-. FISH is very useful in detecting these alterations in MDS and it is an important complement to CC.

Clinical and cytogenetic features of 508 Chinese patients with myelodysplastic syndrome and comparison with those in Western countries.

Myelodysplastic syndrome (MDS) is a clonal hematopoietic stem cell disorder characterized by ineffective hematopoiesis and leukemia progression. Racial differences may exist on clinical pictures and the molecular events leading to MDS, which are heterogeneous. To better define the clinical and cytogenetic features in Chinese patients, a retrospective multicentric study was performed in 508 MDS cases. Compared with Western countries, Chinese patients showed younger age (median: 49 vs 65-73 years), lower percentages of RARS (2.8 vs 6.6-15.3%), and CMML (5.2 vs 11.7-30.6%). Cytogenetically, among 367 cases with evaluable data, abnormal karyotypes were found in 136 cases, including 56 numerical and 80 structural changes. Incidences of single chromosome 5 and 7 abnormalities were lower than those in Western countries (2.2 vs 17.8-42.5%). However, complex cytogenetic aberrations and chromosome translocations were frequently observed and related to poor prognosis. Both multiple chromosome deletions and translocations were detected in advanced subtypes (RAEB and RAEB-T). Analysis of 200 cases revealed a higher incidence of hepatitis-B-virus infection than that in non-MDS population (21.00 vs 9.75%). This study further confirmed: (1) different genetic/environmental backgrounds between Asian and Western MDS populations; (2) a strong predictive value of cytogenetic abnormalities on disease outcome and involvement of genomic instability in leukemia clone development.

Responses of the antioxidant defenses of the Goldfish Carassius auratus, exposed to 2,4-dichlorophenol.

Goldfish Carassius auratus were exposed to 0.1mg/l of 2,4-dichlorophenol (2,4-DCP), widely used as transportation power in China, for 2, 5, 10, 20 and 40 days, while one control group was designated for each exposure group. Antioxidant defenses consisting of contents of reduced glutathione (GSH) and glutathione disulfide (GSSG) and activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), selenium-dependent glutathione peroxidase (Se-GPx) and glutathione S-transferase (GST) in liver of freshwater fish were determined and the GSH-GSSG ratio and content of tGSH (total glutathione) were calculated. In the present study, the role of hepatic antioxidant defenses was evaluated and the possible poisoning mechanism of fish can be explained as an oxidative stress mechanism. In addition, hepatic SOD and GSH, especially tGSH, were sensitive to 2,4-DCP contamination and thus, can possibly be used in early assessment of 2,4-DCP-dominant polluted aquatic ecosystems.

Effects of water-soluble fractions of diesel oil on the antioxidant defenses of the goldfish, Carassius auratus.

Larval goldfish Carassius auratus were exposed to 0.05 and 0.1 mg/L No. 20 diesel oil, widely used as transportation power in China, for 2, 4, 7, 10, 15, 25, and 40 days, while one control group was designated for each exposure group. Some fish after 25 days of exposure were transferred to diluted water until the 40th day. Hepatic antioxidant defense parameters of fish, including contents of reduced glutathione and glutathione disulfide and activities of superoxide dismutase, catalase, glutathione reductase, selenium-dependent glutathione peroxidase, and glutathione S-transferase, were determined and compared to control values. All the results indicated that the antioxidant responses of the fish to the two concentrations of oil exposure were similar on the whole. The possible defense mechanisms of fish and prospective early biomarkers for the evaluation of an oil-dominant contaminated aquatic ecosystem are discussed. In addition, after fish were removed from oil exposure, the recovery status of these antioxidant indices was explored.

Major form of NUP98/HOXC11 fusion in adult AML with t(11;12)(p15;q13) translocation exhibits aberrant trans-regulatory activity.

Three adult patients with de novo acute myeloid leukemia of distinct subtypes harboring t(11;12)(p15;q13) have been investigated to characterize the genes involved in that translocation. Through molecular cytogenetics, a chromosome break was detected at the 3' part of nucleoporin 98 (NUP98) gene at 11p15. Using rapid amplification of cDNA end, we identified the partner gene at 12q13, HOXC11. Molecular analysis showed that exon 12 of NUP98 was fused in-frame to exon 2 of HOXC11 in all three cases with t(11;12)(p15;q13). Therefore, this type of fusion may represent the major form of the NUP98-HOXC11 chimera so far reported. Moreover, two out of three cases had a confirmed deletion of the 3' part of NUP98 gene and more telomeric region of 11p harboring a group of tumor-suppressor genes. Interestingly, the NUP98-HOXC11 protein when assayed in a GAL4 reporter system, showed an aberrant trans-regulatory activity as compared to the wild-type HOXC11 in both COS-7 and HL-60 cells. Therefore, NUP98-HOXC11 may contribute to the leukemogenesis by interfering with the cellular mechanism of transcriptional regulation.

Chitinase genes responsive to cold encode antifreeze proteins in winter cereals.

Antifreeze proteins similar to two different chitinases accumulate during cold acclimation in winter rye (Secale cereale). To determine whether these cold-responsive chitinases require post-translational modification to bind to ice, cDNAs coding for two different full-length chitinases were isolated from a cDNA library produced from cold-acclimated winter rye leaves. CHT9 is a 1,193-bp clone that encodes a 31.7-kD class I chitinase and CHT46 is a 998-bp clone that codes for a 24.8-kD class II chitinase. Chitinase-antifreeze proteins purified from the plant were similar in mass to the predicted mature products of CHT9 and CHT46, thus indicating that there was little chemical modification of the amino acid sequences in planta. To confirm these results, the mature sequences of CHT9 and CHT46 were expressed in Escherichia coli and the products of both cDNAs modified the growth of ice. Transcripts of both genes accumulated late in cold acclimation in winter rye. Southern analysis of winter rye genomic DNA indicated the presence of a small gene family homologous to CHT46. In hexaploid wheat, CHT46 homologs mapped to the homeologous group 1 chromosomes and were expressed in response to cold and drought. We conclude that two novel cold-responsive genes encoding chitinases with ice-binding activity may have arisen in winter rye and other cereals through gene duplication.

Single crystals of a type III antifreeze polypeptide from ocean pout.

Antifreeze protein (HPLC-2) from ocean pout was purified from serum using column chromatography on Sephadex G75 and reverse-phase HPLC columns. Single crystals were grown by batch methods at 4 degrees C from a 1.5 M solution of ammonium sulphate (pH 7.1). The crystals diffracted to about 2.5 A resolution at 4 degrees C and belong to the monoclinic space group P2(1), with cell parameters: a = 39.77 A, b = 58.51 A, c = 30.27 A, beta = 102.28 degrees, with two molecules of 6000 M(r) per asymmetric unit.

[Cytogenetic and molecular studies in patients with chronic myelogenous leukemia without Ph chromosome and with unusual Ph translocation].

Cytogenetic and molecular studies were made in 4 patients with Ph negative chronic myelogenous leukemia (CML) and 4 patients with CML with unusual Ph translocation. Chromosome analysis was performed on direct preparations and short-term cultures of bone marrow cells by R and G bandings. Southern blot analysis of DNA from leukemia cells was made using 4.5kb bcr-u and 1.5kb bcr-HE probes. Four patients with Ph negative CML had normal karyotypes. Among them, 3 had rearrangement of bcr, and 1 expected germ line pattern only. In the 4 patients with CML with unusual Ph translocation who had bcr rearrangement, one had a masked Ph chromosome originating from a translocation t(3;22) (p22;q11), the other three had one of the following complex Ph translocations: t(9;22;13) (q34;q11;q21), t(3;14;22) (p21;q32;q11) and t(X;9;22;12) (q22; q34; q11; q24). Our data confirmed that Ph negative CML could be divided into two different subsets: Ph-bcr+ CML and Ph-bcr-CML and that whatever the type of translocation may be, CML with unusual Ph translocation and Ph positive CML had a common molecular pathological basis.

Crystallization of Bacillus subtilis tryptophanyl-tRNA synthetase.

Tryptophanyl-tRNA synthetase from Bacillus subtilis was overexpressed in Escherichia coli and was purified using column chromatography on DEAE-Sephacel and hydroxyapatite columns. Single crystals of the synthetase were grown by vapor diffusion at 4 degrees C from pH 5.5 solutions of polyethylene glycol 8000 containing magnesium ATP and L-tryptophan. The crystals diffracted to about 4.0 A resolution at -150 degrees C and appeared to belong to the orthorhombic space group P2(1)2(1)2 with unit cell dimensions: a = 143.6 A, b = 111.6 A, c = 50.6 A with one dimer in the asymmetric unit.

A clinical and experimental study on all-trans retinoic acid-treated acute promyelocytic leukemia patients.

Fifty patients with acute promyelocytic leukemia (APL) have been treated with all-trans retinoic acid (RA). In vitro induced differentiation of primarily cultured bone marrow cells from the patients, colony-forming unit granulocyte-macrophage (CFU-GM) and L-CFU colony-forming assays, and karyotype analysis were performed over the treatment course. The very high bone marrow complete remission (CR) rate (94%) suggested that all-trans RA was superior to conventional chemotherapeutic regimens for the treatment of APL. The leukemic clone was reduced by RA-induced terminal differentiation and loss of proliferation capacity of leukemic cells. Relapse after CR in about 40% of patients was the major reason for the failure of the RA treatment. Patients who relapsed after a chemotherapy-maintained CR could be effectively reinduced to second CR by RA. However, if relapse occurred after a CR maintained by both RA and chemotherapy, the sensitivity of newly emerged leukemic clones to RA was greatly reduced. Therefore, it is suggested that RA should be replaced by conventional chemotherapy as soon as CR is achieved. Laboratory studies proved valuable in selecting cases for RA therapy and in predicting therapeutic effects and prognosis.

A case of basophilic leukemia bearing simultaneous translocations t(8;21) and t(9;22).

We report a case of basophilic leukemia with simultaneous translocations of t(8;21) and t(9;22). The patient's clinical and hematologic findings were characteristic only of t(9;22) but not of t(8;21). This unusual cytogenetic phenomenon raises a challenge to the current concepts of primary chromosomal abnormalities in cancer.

Isochromosome 11q in a case of acute myelomonocytic leukemia FAB type M4.

The clinical and cytogenetic findings in a 42-year-old female with acute myelomonocytic leukemia (AMMoL) were reported. At diagnosis, cytogenetic studies of bone marrow cells revealed the karyotype 45; XX, +8, -11, -17, -18, +i (11q). To our knowledge, this is the second case of AMMoL with i(11q) in the literature.

Sequential observation of clinical and karyotypic evolution in a patient with myelodysplastic syndrome.

This paper reports an interesting case of myelodysplastic syndrome (MDS), whose bone marrow karyotype at diagnosis was 46, XY, t(16;17) (q12;q25). Fourteen months later, the disease transformed into erythroleukemia, and several correlative clones with hyperdiploid appeared at the same time. Thus, we consider that detecting karyotypic evolution may help evaluate the prognosis of MDS.

[Acute promyelocytic leukemia and 15;17 chromosome translocation].

Cytogenetic studies using Giemsa R-bands after a short term culture of bone marrow or peripheral blood were done in 20 cases of acute promyelocytic leukemia (APL), including three cases of microgranular variant. As a result, t (15;17) cells were found in all the cells, and the percentages of the abnormal cells were 38-100%. In 2 cases, t(15;17) was seen in 88% and 65% of the cells in cultured specimens, whereas no such translocation was seen in direct specimens. Among 6 cases treated with tretinoin, 5 achieved complete remission, and among 14 cases treated by HOAP protocol 2 achieved complete remission. Reexamination of 4 of these cases during the stage of complete remission failed to find t(15;17). These data revealed that t(15;17) may probably be present in all cases of APL, and therefore is a very useful diagnostic criterion, especially in cases of micro granular APL. But the detection rate is determined by methodology, which requires special precaution.