Inhibition of pyrimidine biosynthesis by strobilurin derivatives induces differentiation of acute myeloid leukemia cells.

All-trans retinoic acid-based differentiation therapies have succeeded in the treatment of acute promyelocytic leukemia, which is a rare subtype of acute myeloid leukemia (AML). Their clinical efficacy is negligible, however, for other subtypes of AML. Here, we showed that strobilurin derivatives, a well-established class of inhibitors of mitochondrial electron transport chain (ETC) complex III, possessed differentiation-inducing activity in AML cells. Impairment of mitochondrial ETC activity was involved in the differentiation effects of strobilurin derivatives, where reactive oxygen species generation appeared unnecessary. Conversely, strobilurin derivative-mediated differentiation was triggered by pyrimidine deficiency, which resulted from the inhibition of the mitochondrial-coupled dihydroorotate dehydrogenase enzyme. Moreover, strobilurin derivative-mediated pyrimidine depletion led to the activation of the Akt/mTOR cascade, which was required for the differentiation. Our study provided evidence that strobilurin derivatives may represent a novel class of differentiation-inducing agents for the treatment of AML.

Salt-inducible kinase inhibition sensitizes human acute myeloid leukemia cells to all-trans retinoic acid-induced differentiation.

Differentiation therapies with all-trans retinoic acid (ATRA) have been successful in treating acute promyelocytic leukemia, a rare subtype of acute myeloid leukemia (AML). However, their efficacy is limited in the case of other AML subtypes. Here, we show that the combination of ATRA with salt-inducible kinase (SIK) inhibition significantly enhances ATRA-mediated AML differentiation. SIK inhibition augmented the ability of ATRA to induce growth inhibition and G1 cell cycle arrest of AML cells. Moreover, combining ATRA and SIK inhibition synergistically activated the Akt signaling pathway but not the MAPK pathway. Pharmacological blockade of Akt activity suppressed the combination-induced differentiation, indicating an essential role for Akt in the action of the combination treatment. Taken together, our study reveals a novel role for SIK in the regulation of ATRA-mediated AML differentiation, implicating the combination of ATRA and SIK inhibition as a promising approach for future differentiation therapy.

Single-Dose Administration of Recombinant Human Thrombopoietin Mitigates Total Body Irradiation-Induced Hematopoietic System Injury in Mice and Nonhuman Primates.

PURPOSE: Recombinant human thrombopoietin (rhTPO) has been evaluated as a therapeutic intervention for radiation-induced myelosuppression. However, the immunogenicity induced by a repeated-dosing strategy raises concerns about the therapeutic use of rhTPO. In this study, single-dose administration of rhTPO was evaluated for efficacy in the hematopoietic response and survival effect on mice and nonhuman primates exposed to total body irradiation (TBI). METHODS AND MATERIALS: Survival of lethally (9.0 Gy) irradiated C57BL/6J male mice was observed for 30 days after irradiation. Hematologic evaluations were performed on C57BL/6J male mice given a sublethal dose of radiation (6.5 Gy). Furthermore, in sublethally irradiated mice, we performed bone marrow (BM) histologic evaluation and evaluated BM-derived clonogenic activity. Next, the proportion and number of hematopoietic stem cells (HSCs) were analyzed. Competitive repopulation experiments were conducted to assess the multilineage engraftment of irradiated HSCs after BM transplantation. Flow cytometry was used to evaluate DNA damage, cell apoptosis, and cell cycle stage in HSCs after irradiation. Finally, we evaluated the efficacy of a single dose of rhTPO administered after 7 Gy TBI in male and female rhesus monkeys. RESULTS: A single administration of rhTPO 2 hours after irradiation significantly mitigated TBI-induced death in mice. rhTPO promoted multilineage hematopoietic recovery, increasing peripheral blood cell counts, BM cellularity, and BM colony-forming ability. rhTPO administration led to an accelerated recovery of BM HSC frequency and multilineage engraftment after transplantation. rhTPO treatment reduced radiation-induced DNA damage and apoptosis and promoted HSC proliferation after TBI. Notably, a single administration of rhTPO significantly promoted multilineage hematopoietic recovery and improved survival in nonhuman primates after TBI. CONCLUSIONS: These findings indicate that early intervention with a single administration of rhTPO may represent a promising and effective radiomitigative strategy for victims of radiation disasters.

Vibsanol A induces differentiation of acute myeloid leukemia cells via activation of the PKC signaling pathway and induction of ROS.

Identifying novel differentiating agents to promote leukemia-cell differentiation is a pressing need. Here, we demonstrated that vibsanol A, a vibsane-type diterpenoid, inhibited the growth of acute myeloid leukemia (AML) cells via induction of cell differentiation, which was characterized by G1 cell cycle arrest. The differentiation-inducing effects of vibsanol A were dependent upon protein kinase C (PKC) activation, and subsequent activation of the extracellular signal-regulated kinase (ERK) pathway. Furthermore, vibsanol A treatment increased reactive oxygen species (ROS) levels, and the ROS scavenger NAC reversed the vibsanol A-induced cell differentiation, indicating an important role for ROS in the action of vibsanol A. Finally, vibsanol A exhibited a differentiation-enhancing effect when used in combination with all-trans retinoic acid in AML cells. Overall results suggested that vibsanol A induces AML cell differentiation via activation of the PKC/ERK signaling and induction of ROS. Vibsanol A may prove to be an effective differentiating agent against AML.

[Therapeutic Effect of Recombinant Human Stem Cell Factor on Rhesus Monkeys with Severe Acute Radiation Sickness].

OBJECTIVE: To study the therapeutic effect of rhSCF early administration on rhesus monkeys with severe acute radiation sickness(ARS). METHODS: Twelve adult monkeys totally exposed to 7.0 Gy 60Co were divided into radiation control and SCF groups, and monkeys in SCF group were subcutaneously injected recombinant human SCF(rhSCF) 200 µg/kg at half an hour and 24 hour after irradiation, while the radiation control monkeys were injected physiological saline. Survival was monitored and hematopoiesis was evaluated at 40 days following early treatment. RESULTS: 6 animals treated with rhSCF all survived, while 2 in irradiated controls survived on 40 day after radiation. rhSCF treatment promoted hematopoiesis recovery significantly, increased the nadir of white blood cells, neutrophils and platelets, and simplified supportive care in ARS rhesus monkeys. CONCLUSION: RhSCF injection soon after TBI taken shows an significant therapeutic efficiency on rhesus monkeys with severe acute radiation sickness.

Succinate ester derivative of δ-tocopherol enhances the protective effects against 60Co γ-ray-induced hematopoietic injury through granulocyte colony-stimulating factor induction in mice.

α-tocopherol succinate (α-TOS), γ-tocotrienol (GT3) and δ-tocotrienol (DT3) have drawn large attention due to their efficacy as radioprotective agents. α-TOS has been shown to act superior to α-tocopherol (α-TOH) in mice by reducing lethality following total body irradiation (TBI). Because α-TOS has been shown to act superior to α-tocopherol (α-TOH) in mice by reducing lethality following total body irradiation (TBI), we hypothesized succinate may be contribute to the radioprotection of α-TOS. To study the contributions of succinate and to identify stronger radioprotective agents, we synthesized α-, γ- and δ-TOS. Then, we evaluated their radioprotective effects and researched further mechanism of δ-TOS on hematological recovery post-irradiation. Our results demonstrated that the chemical group of succinate enhanced the effects of α-, γ- and δ-TOS upon radioprotection and granulocyte colony-stimulating factor (G-CSF) induction, and found δ-TOS a higher radioprotective efficacy at a lower dosage. We further found that treatment with δ-TOS ameliorated radiation-induced pancytopenia, augmenting cellular recovery in bone marrow and the colony forming ability of bone marrow cells in sublethal irradiated mice, thus promoting hematopoietic stem and progenitor cell recovery following irradiation exposure. δ-TOS appears to be an attractive radiation countermeasure without known toxicity, but further exploratory efficacy studies are still required.

[Therapeutic Effect of Combined Cytokines on Nonhuman Primate Model of Severe Haemopoietic Acute Radiation Sickness].

OBJECTIVE: To evaluate the therapeutic effects of combined administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF), recombinant human thrombopoietin (rhTPO) and recombinant human interleukin-2 (rhIL-2) on radiation-induced severe haemopoietic acute radiation sickness (ARS) in rhesus monkeys, so as to provide experimental evidences for the effective clinical treatment. METHODS: Seventeen rhesus monkeys were exposed to 7.0 Gy (60)Co γ-ray total body irradiation (TBI) to establish severe haemopoietic ARS model, and were randomly divided into supportive care group, rhG-CSF+rhTPO treatment group and rhG-CSF+rhTPO+rhIL-2 treatment group. Survival time, general signs such as bleeding and infections, and peripheral blood cell counts in each group were monitored. Bone marrow cells were cultivated to examine the colony formation ability. The histomorphology changes of bone marrow were observed at 45 d post irradiation. RESULTS: After 7.0 Gy (60)Co γ-ray TBI, monkeys of supportive care group underwent tarry stool and emesis, then died in 12~18 d. The overall survival rate in this group was 16.7%. Gastrointestinal reactions of monkeys in two combined-cytokines treatment groups were inapparent. Combined-cytokines treatment induced 100% survival. Complete blood cells declined sharply after irradiation in each group, but two combined-cytokines treatment schemes could elevate the nadir of all blood cells, shorten the duration of pancytopenia and accelerate the recovery of hemogram. Compared with rhG-CSF+ rhTPO treatment, rhG-CSF+ rhTPO+ rhIL-2 treatment could increase the counts of lymphocytes and monocytes. The colony-formation rate of haemopoietic stem/progenitor cells in bone marrow dropped markedly at 2 d after irradiation. Combined-cytokines treatment promoted the ability of colony formation on day 29. Hematopoietic cells mostly disappeared in bone marrow of animals in supportive care group, but hematopoietic functions were recovered after cytokines were administrated. CONCLUSION: rhG-CSF+ rhTPO and rhG-CSF+ rhTPO+ rhIL-2 treatment can significantly promote hematopoiesis recovery, improve the quantity of life, simplify the supportive therapy, and enhance the survival rate of rhesus monkeys with severe haemopoietic ARS induced by 7.0 Gy (60)Co γ-ray exposure. Especially the application of rhIL-2 can accelerate the recovery of lymphocytes and monocytes and restore the immunological function. Thus, combination of rhG-CSF, rhTPO and rhIL-2 on the basis of supportive care is an efficient strategy to treat severe haemopoietic ARS.

Natural Product Vibsanin A Induces Differentiation of Myeloid Leukemia Cells through PKC Activation.

All-trans retinoic acid (ATRA)-based cell differentiation therapy has been successful in treating acute promyelocytic leukemia, a unique subtype of acute myeloid leukemia (AML). However, other subtypes of AML display resistance to ATRA-based treatment. In this study, we screened natural, plant-derived vibsane-type diterpenoids for their ability to induce differentiation of myeloid leukemia cells, discovering that vibsanin A potently induced differentiation of AML cell lines and primary blasts. The differentiation-inducing activity of vibsanin A was mediated through direct interaction with and activation of protein kinase C (PKC). Consistent with these findings, pharmacological blockade of PKC activity suppressed vibsanin A-induced differentiation. Mechanistically, vibsanin A-mediated activation of PKC led to induction of the ERK pathway and decreased c-Myc expression. In mouse xenograft models of AML, vibsanin A administration prolonged host survival and inhibited PKC-mediated inflammatory responses correlated with promotion of skin tumors in mice. Collectively, our results offer a preclinical proof of concept for vibsanin A as a myeloid differentiation-inducing compound, with potential application as an antileukemic agent. Cancer Res; 76(9); 2698-709. ©2016 AACR.

The protein kinase C agonist prostratin induces differentiation of human myeloid leukemia cells and enhances cellular differentiation by chemotherapeutic agents.

As acute myeloid leukemia (AML) cells are characterized by uncontrolled self-renewal and impaired cellular differentiation, induction of terminal differentiation of leukemia cells by differentiating agents has been proposed as an attractive therapeutic strategy to treat AML. Here, we demonstrated that prostratin, a potent protein kinase C (PKC) activator, inhibited the growth of myeloid leukemia cells by a predominant G1 arrest with variable induction of apoptosis. Conversely, prostratin induced significant differentiation of AML cell lines and primary AML blasts as evidenced by morphology and immunophenotyping. The effects of prostratin were PKC dependent, and activation of mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK) 1/2 by PKC was required for prostratin-induced cell differentiation. Consequently, prostratin reprogrammed transcriptional factor expression, and ectopic expression of c-Myc in HL-60 cells significantly eliminated prostratin-mediated cellular differentiation and cell cycle arrest, indicating an essential role for c-Myc suppression in the differentiation-inducing effects of prostratin. Finally, prostratin was able to potentiate cellular differentiation induced by chemotherapeutic agents such as Ara-C. Together, we proposed that prostratin alone or administered with other anticancer agents may be effective in differentiation therapy of AML.

[Study on the effect of vibsane-type diterpenoids of Viburnum odoratissimum on human HepG2 cell growth and its underlying mechanism].

OBJECTIVE: To study the antiproliferation effect on HepG2 cells and its underlying mechanism of the active chemical composition of the Viburnum Odoratissimum. METHODS: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction assay and trypan blue dye exclusion assay were used to assess the effect of vibsane-type diterpenoids on the proliferation of various tumor cells. Alterations in cell cycle and apoptosis were determined by flowcytometry. The enzymatic activity of caspase-3/7 was measured by Apo-ONE homogeneous Caspase-3/7 Assay kit. RESULTS: Compound 1 #, a vibsane-type diterpenoid, was found to significantly inhibit the growth of HepG2 cells by anticancer proliferation activity screening. It was demonstrated that the modified groups on side chain coupled to C11 site affected the cell growth-inhibition activity of compounds by structure-activity analysis. In addition, HepG2 cell line was most sensitive to compound 1 #, which induced growth arrest of HepG2 cells in a dose- and time-dependent manner. Study on the mechanisms underlying these effects indicated that compound 1 # induced significant G0/G1 phase arrest of HepG2 cells in a time- and concentration-dependent manner. Meanwhile, It was found that higher concentrations of compound (5-10 micromol/L) caused evident increase in the unmber of apoptotic cells and dose-dependent activation of caspase-3/7. CONCLUSION: Vibsane-type diterpenoids could significantly inhibit the growth of HCC HepG2 cells. Induction of cell cycle arrest and apoptosis may play important roles in their anticancer effects.

Steroidal saponins from Tribulus terrestris.

Sixteen steroidal saponins, including seven previously unreported compounds, were isolated from Tribulus terrestris. The structures of the saponins were established using 1D and 2D NMR spectroscopy, mass spectrometry, and chemical methods. They were identified as: 26-O-ß-d-glucopyranosyl-(25R)-furost-4-en-2α,3ß,22α,26-tetrol-12-one (terrestrinin C), 26-O-ß-d-glucopyranosyl-(25R)-furost-4-en-22α,26-diol-3,12-dione (terrestrinin D), 26-O-ß-d-glucopyranosyl-(25S)-furost-4-en-22α,26-diol-3,6,12-trione (terrestrinin E), 26-O-ß-d-glucopyranosyl-(25R)-5α-furostan-3ß,22α,26-triol-12-one (terrestrinin F), 26-O-ß-d-glucopyranosyl-(25R)-furost-4-en-12ß,22α,26-triol-3-one (terrestrinin G), 26-O-ß-d-glucopyranosyl-(1→6)-ß-d-glucopyranosyl-(25R)-furost-4-en-22α,26-diol-3,12-dione (terrestrinin H), and 24-O-ß-d-glucopyranosyl-(25S)-5α-spirostan-3ß,24ß-diol-12-one-3-O-ß-d-glucopyranosyl-(1→4)-ß-d-galactopyranoside (terrestrinin I). The isolated compounds were evaluated for their platelet aggregation activities. Three of the known saponins exhibited strong effects on the induction of platelet aggregation.

[Protective effects of WR2721 on early bone marrow hematopoietic function in mice exposed to 6.5 Gy of (60)Co γ-rays].

The aim of this study was to investigate the effect of WR2721(amifostine) against bone marrow hematopoietic damage of mice exposed to 6.5 Gy of (60)Co-γ ray. A total of 60 C57/BL6J mice was divided into 3 groups:normal group (mice were injected with physiological salt solution), irradiation group (mice were injected with physiologic salt solution before irradiation) and WR2721 group (mice were injected with WR2721 before irradiation). The WBC, neutrophil (Neut), Plt and RBC levels in peripheral blood of 3 group mice were counted within 60 days after irradiation; the bone marrow nuclear cells (BMNC) were counted at 2 and 24 hours after irradiation; the hematopoietic stem/progenitor cell (LK/LSK) level and colony formation capability were detected by flow cytometry at 2 and 24 hours after irradiation. The results indicated that the counts of WBC and neut at 4 and 18 days, Plt at 7-18 days and RBC at 10-30 day after irradiation in WR2721 group were higher than those in irradiation group (P < 0.05); the BMNC, LSK and LK levels obviously increased at 24 hours after irradiation (P < 0.05), the CFU-GEMM, CFU-GM, CFU-MK BFU-E and CFU-E all significantly increased at 2 and 24 hours after irradiation (P < 0.01), as compared with irradiation group. It is concluded that WR2721 can effectively alleviate early hematopoietic damage and promote the fast recovery of peripheral blood cells in mice exposed to γ-ray, suggesting that the WR2721 has significant radioprotective effect on hematopoietic system.

[Chemistry and biological activities of Viburnum odoratissimum].

Viburnum odoratissimum is a folk medicinal plant, it can dredge the meridian passage and contains mainly diterpenes, triterpenes, flavonoids, sesquiterpenes, lignans, coumarin glycosides, etc. Vibsanin-type diterpenoids are the characteristic compounds of V. odoratissimum, and are divided into eleven-membered ring, seven-membered ring, and rearrangement-type. Vibsanin B, vibsanin C and neovibsanin A are the representative compounds of the three subtypes of vibsanin-type diterpenoids respectively. V. odoratissimum has cytotoxic activity, antibacterial activity, fish piscicidal activity and activity of inhibiting the growth of plants, Cytotoxic activity is the main biological activity.

[Transfection of ECSOD to Rhesus bone marrow mesenchymal stem cells in vitro].

This study was aimed to investigate the biological effects of Rhesus bone marrow mesenchymal stem cells (R-BMMSC) transfected by adenovirus bearing extracellular superoxide dismutase gene (AD-ECSOD). Using density gradient centrifugation and adherent culture way, the R-BMMSC transfected by AD-ECSOD and reporter gene EGFP were isolated, cultured and purified; the transfection efficiency was detected by fluorescence microscopy and flow cytometry; the ECSOD protein expression in cell culture supernatant were detected by ELISA; the surface antigens on R-BMMSC (CD34, CD29, CD45, CD90, HLA-DR) were detected by flow cytometry; and differentiation capability of transfected R-BMMSC were detected by oil red O and alizarin staining; the proliferation capability of R-BMMSC was assay by MTT method. The results showed that the transfection efficiency of AD-ECSOD (MOI 500, 1 000, 1 500 and 2 000) for R-BMMSC was > 95%. At 24 h after transfection, the ECSOD protein could be detected in cell culture supernatant, and its level was significantly higher than that of control group (P < 0.01). At 48 h after transfection, the expression level of ECSOD protein on MOI 1 500 and 2 000 was the highest. The proliferative capability, surface antigen expression and multi directive differentiation ability of transfected R-BMMSC were similar to non-transfected R-BMMSC. It is concluded that the AD-ECSOD can effectively transfect the R-BMMSC without influences on its biological features.

Steroidal glycosides from the rhizomes of Anemarrhena asphodeloides and their antiplatelet aggregation activity.

Five new steroidal glycosides, timosaponin J ( 1), timosaponin K ( 2), (25 S)-karatavioside C ( 5), timosaponin L ( 6), and (25 S)-officinalisnin-I ( 8), together with eight known steroidal saponins, timosaponin E (1) ( 3), purpureagitosid ( 4), timosaponin BII ( 7), timosaponin B III ( 9), anemarrhenasaponin I ( 10), anemarrhenasaponin III ( 11), anemarrhenasaponin A (2) ( 12), and timosaponin A III ( 13), were isolated from the rhizomes of Anemarrhena asphodeloides. Their structures were elucidated on the basis of spectroscopic and chemical evidence. The aglycones of compounds 1 and 2 are new aglycones. Compounds 1- 13 were evaluated for their platelet aggregation activities, and compound 13 exhibited the strongest inhibitory effect on adenosine diphosphate (ADP)-induced platelet aggregation.

Spirostanol saponins derivated from the seeds of Trigonella foenum-graecum by ß-glucosidase hydrolysis and their inhibitory effects on rat platelet aggregation.

Nine spirostanol saponins (1-9) and seven mixtures of 25 R and 25 S spirostanol saponin isomers (10-16) were obtained from the seeds of Trigonella foenum-graecum after enzymatic hydrolysis of the furostanol saponin fraction by ß-glucosidase. Their structures were determined by NMR and MS spectroscopy. Among them, 1- 4, 6, 8, and 9 were new compounds and five, 11B, 12A, 13B, 14A, and 14B, were new structures observed from seven mixtures. In addition, the inhibitory effects of all saponins on rat platelet aggregation were evaluated.

High dose granulocyte colony-stimulating factor enhances survival and hematopoietic reconstruction in canines irradiated by 2.3 Gy mixed fission neutron and gamma ray.

This study was purposed to evaluate the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on hematopoietic reconstruction and survival in beagles exposed to mixed fission neutron and γ-ray. 13 beagles were unilaterally exposed to single dose of 2.3 Gy 90% neutrons. The experiments were divided into 3 groups: irradiation control group (no any treatment, n = 4), supportive care group (n = 5) and rhG-CSF plus supportive care group (n = 4, abbreviated as rhG-CSF group) in which the beagles were subcutaneously injected with 200 µg/kg of rhG-CSF early at half an hour and 24 hours post-irradiation respectively. The results showed that 2.3 Gy 90% neutron irradiation induced a severe acute radiation sickness of bone marrow type. The administration of rhG-CSF increased the survival rate from 60% in supportive care group to 100%. Twice injection of rhG-CSF in the first 24 hours reduced duration of neutropenia, enhanced neutrophil nadir and promoted neutrophil recovery when compared with control cohort administered clinical support. The number of colony-forming cells (CFU-GM, CFU-E, and BFU-E) in peripheral blood of rhG-CSF treated canines increased 2-to 5-fold relative to those of the supportive care group on day 3. All canines treated with rhG-CSF achieved hematopoietic reconstruction as evidenced by the pathological section of sternum while severe shortage of hemopoietic cells remained in the cohorts given supportive care alone. It is concluded that the combination of supportive care and high-dose rhG-CSF can accelerate hematopoietic recovery and enhance survival of dogs exposed to 2.3 Gy mixed neutron and gamma ray.

RhG-CSF improves radiation-induced myelosuppression and survival in the canine exposed to fission neutron irradiation.

Fission-neutron radiation damage is hard to treat due to its critical injuries to hematopoietic and gastrointestinal systems, and so far few data are available on the therapeutic measures for neutron-radiation syndrome. This study was designed to test the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in dogs which had received 2.3 Gy mixed fission-neutron-γ irradiation with a high ratio of neutrons (~90%). Following irradiation, rhG-CSF treatment induced 100% survival versus 60% in controls. Only two of five rhG-CSF-treated dogs experienced leukopenia (white blood cells [WBC] count < 1.0 × 10(9)/L) and neutropenia (neutrophil [ANC] count < 0.5 × 10(9)/L), whereas all irradiated controls displayed a profound period of leukopenia and neutropenia. Furthermore, administration of rhG-CSF significantly delayed the onset of leukopenia and reduced the duration of leucopenia as compared with controls. In addition, individual dogs in the rhG-CSF-treated group exhibited evident differences in rhG-CSF responsiveness after neutron-irradiation. Finally, histopathological evaluation of the surviving dogs revealed that the incidence and severity of bone marrow, thymus and spleen damage decreased in rhG-CSF-treated dogs as compared with surviving controls. Thus, these results demonstrated that rhG-CSF administration enhanced recovery of myelopoiesis and survival after neutron-irradiation.

[Effect of rhG-CSF on blood coagulation in beagles irradiated by 2.3 Gy neutron].

The aim of this study was to investigate the effect of recombinant human granulocyte stimulating factor (rhG-CSF) on blood coagulation of beagles irradiated by 2.3 Gy neutron so as to provide new therapy for blood coagulation disorder after neutron irradiation. 10 beagles were exposed to 2.3 Gy neutron, and then randomly assigned into supportive care group and rhG-CSF-treated group. The rhG-CSF-treated cohorts were injected subcutaneously with rhG-CSF (10 µg/kg·d) beginning at the day of exposure for 21 consecutive days. Peripheral blood platelet counts were examined once every two days. In vitro platelet aggregation test, thromboelastography and blood clotting tetrachoric tests were also performed. The results indicated that the blood clotting system of irradiated dogs was in hypercoagulable state in the early days after 2.3 Gy neutron irradiation, and became hypocoagulable at crisis later and were mainly on intrinsic coagulation pathway. Blood fibrinogen increased markedly during the course of disease, while platelet counts and aggregation function were decreased remarkably. rhG-CSF administered daily could correct hypercoagulable state induced by 2.3 Gy neutron irradiation at the early time post exposure, shortened the thromboplastin generation time and clotting formation, down-regulated the abnormal high fibrinogen in blood, and improved platelet aggregation function. It is concluded that rhG-CSF can improve coagulation disorders of irradiated dogs.

Structural requirement of spirostanol glycosides for rat uterine contractility and mode of their synergism.

OBJECTIVES: Total steroidal saponins extracted from the rhizome of Paris polyphylla (TSSP) have been used in China for the treatment of abnormal uterine bleeding. The aim of this study was to analyse the structure-activity relationship of steroidal saponins purified from P. polyphylla Sm. var. yunnanensis on rat myometrial contractions, and investigate the synergism among themselves as well as with known inherent agonists, such as Prostaglandin F(2alpha) (PGF-2alpha). METHODS: In this study, 22 steroidal saponins purified from TSSP were screened for their contractile activity in isolated uterine strips from estrogen-primed rats. KEY FINDINGS: It was shown that spirostanol glycosides exhibited inducible or inhibitory activity in rat uterine contraction based on the difference of their structures, which was not only attributed in part to the number, the length and the position of sugar side chains attached by a glycoside, but also related to the structure of the aglycone. Furthermore, synergistic actions were observed among pennogenin or diosgenin glycosides as well as with the known inherent agonist PGF-2alpha, indicating they may share, at least in part, similar pathways with PGF-2alpha in stimulating myometrial contractions. Finally, the contractile response of rat myometrium to spirostanol glycosides was significantly enhanced with advancing pregnancy. CONCLUSIONS: Together, these data support the possibility that some spirostanol glycosides may represent a new type of contractile agonist for the uterus and their synergism may be responsible for the therapeutic effect of TSSP on abnormal uterine bleeding.