Hydrogen Bonding-Induced Assembled Structures and Photoresponsive Behavior of Azobenzene Molecule/Polyethylene Glycol Complexes.

We investigated the self-assembled structures and photoresponsive and crystallization behaviors of supramolecules composed of 4-methoxy-4'-hydroxyazobenzene (Azo) molecules and polyethylene glycol (PEG) that were formed through hydrogen-bonding interactions. The Azo/PEG complexes exhibited the characteristics of photoresponse and crystallization, which originated from Azo and PEG, respectively. When Azo/PEG complexes were dissolved in solvents, hydrogen-bonding interaction hindered the rotation and inversion of mesogens, causing a reduction in the photoisomerization rate compared with the photoisomerization rate of the neat Azo. The confinement of Azo/PEG complexes in thin films further resulted in a substantial decrease in the photoisomerization rate but an increase in the amounts of H-aggregated and J-aggregated mesogens. Regarding PEG crystallization, ultraviolet irradiation of Azo/PEG complexes increased the quantity of high-polarity cis isomers, which improved the compatibility between mesogens and PEG, subsequently increasing the crystallization temperature of PEG. Moreover, the complexation of Azo and PEG induced microphase separation, forming a lamellar morphology. Within the Azo-rich microphases, mesogens aggregated to form tilted monosmectic layers. By contrast, PEG crystallization within the PEG-rich microphases was hard confined, indicating that the domain size of the lamellar morphology was unchanged during PEG crystallization.

[Research Progress of Desialylation in Immune Thrombocytopenia -Review].

Some patients diagnosed as immune thrombocytopenia(ITP) have poor response to common first-line therapy such as corticosteroid and immunoglobulin. Studies in recent years have found a FC-independent platelet clearance pathway exists, which is characterized by desialylation of platelet surface glycoprotein(GP), recognition and phagocytosis by Ashwell-Morell receptor(AMR) on hepatocytes, independent on Fc receptors of the reticuloendothelial system. The up-regulation of neuraminidase-1(Neu1) expression on platelet caused by various factors, such as cold storage of platelet, septicemia and ITP could desialylate GPs. It has been found that ITP with positive anti-GPIbα antibody mostly has a poor response to first-line therapy and indicated that such antibody may lead to FC-independent platelet clearance. It also has been proved that anti-GPIbα antibody could desialylate GPs on platelet in animal experiments. Researchers have tris to use sialidase inhibitor agent to treat ITP and got a persistent response of platelet. Here, the desialylation of platelet and its role in ITP pathogensis and therapy are reviewed.

Thrombotic storm in a 4-year-old boy with a thrombus in the right atrium.

Thrombotic storm (TS) is a rare disease, especially with thrombus in the heart of pediatric patient. We present a case of a 4-year-old boy, who was diagnosed with TS during his first hospitalization due to lower extremity deep venous thrombosis, pulmonary embolism, and thrombosis of the inferior vena cava, cerebral, left internal jugular, portal, renal, and iliac veins. He was eventually prescribed with rivaroxaban to control thrombosis after 30 days of successive use of low-molecular-weight heparin, unfractionated heparin, and warfarin, which were demonstrating little effect on preventing thrombosis, and the patient was intolerant to argatroban. While his lupus anticoagulant ratio was slightly above the normal range and no other potential causes such as congenital thrombophilia, severe infection, malignancy, and trauma were confirmed, we suspected antiphospholipid antibody syndrome and prescribed glucocorticoid and rituximab to control the disease. After 36 days of admission, ultrasonography showed recanalization of the former thrombus. One month after discharge, a tumor embolus resembling a mass emerged in his right atrium under effective anticoagulant therapy. During his second admission, he underwent surgical thrombectomy, and pathological examination confirmed the mass to be a platelet-rich thrombus rather than tumor embolus or infection. Considering the suspected antiphospholipid antibody syndrome as the cause of the TS, we prescribed aspirin combined with rivaroxaban to prevent thrombosis. In this case, surgery and pathology shed light on the type of thrombus that emerged from the inferior vena cava and traveled to the heart, which is the possible potential cause of TS. It also changed our therapeutic strategy to antiplatelet therapy combined with anticoagulant therapy to control the disease.

[Relationship between platelet specific antibodies and the onset, clinical manifestation, treatment and prognosis of ITP].

Immune thrombocytopenia (ITP) is an autoimmune hemorrhagic disease. It is considered that production of platelet auto-antibodies was one of the pathogenesis of ITP, first-line therapy including corticosteroid and immunoglobulin could reduce destruction of platelets by inhibiting production of auto-antibodies and blocking Fc-receptor of reticuloendothelial system, but some of the patients were refractory to first-line therapy and have persistent duration of the disease, having worse prognosis and developing into chronic/refractory ITP(C/RITP) . Platelet membrane glycoprotein like GPIIb/IIIa and GPIbα are the most common antigen targets, but first-line therapy was less effective to patients whose anti-GPIbα antibodies are positive. Further studies revealed that the way causing platelet destruction by anti-GPIIb/IIIa antibodies and anti-GPIbα antibodies are different: the former is mainly dependent to Fc-pathway, and the latter mainly cleared platelet by Fc-independent way. Results above indicated that detection of type of platelet auto-antibodies maybe potential to treatment and prognosis of ITP. This article summarizes relationship between platelet specific antibodies and the onset, clinical manifestation, treatment and prognosis of ITP.

[Clinical analysis of recombinant humanized thrombopoietin for treating 25 children with severe immune thrombocytopenia].

This study was aimed to evaluate the efficacy and safety of recombinant humanized thrombopoietin (rhTPO) for treating children with severe immune thrombocytopenia (ITP). A total of 25 patients with severe ITP who accepted rhTPO treatment for 14 days between December, 2009 and November, 2012 in Beijing Children's Hospital was retrospectively analyzed. The results showed that the median platelet counts of all 25 patients increased from the lowest level 4.0×10(9)/L (0×10(9)/L-10×10(9)/L) to the highest level 71×10(9)/L (14×10(9)/L-439×10(9)/L) on median 11 days (range from 3 days to 15 days). After rhTPO discontinuation, the platelet counts of patients gradually decreased. Complete response rate was 44% (11/25), response rate was 32% (8/25), non-response rate was 24% (6/25) and total response rate was 76% (19/25). The platelet count in the patients who showed complete response to rhTPO therapy reached the highest 112×10(9)/L (43×10(9)/L-439×10(9)/L) on median 12 days(range from 7 days to 15 days). The patients showed response to rhTPO treatment on median 4 days (range from 1 days to 11 days). The platelet count decreased gradually after the discontinuation of rhTPO administration but still significantly higher on 28 days than the level before the treatment (P < 0.05). 12 patients who did not respond to γ-globulin before rhTPO treatment showed response to γ-globulin after the discontinuation of rhTPO therapy. 2 patients showed mild clinical adverse reaction. It is concluded that rhTPO is an effective and safe treatment method for children with severe ITP. It will help the patient smoothly through the dangerous period of severe bleeding, but the platelet count decreases gradually after rhTPO discontinuation. Maintenance treatment is needed to consolidate the curative efficacy.

[Advance in thrombopoietic drugs used in treatment of children's immune thrombocytopenia].

Immune thrombocytopenia (ITP) is a common acquired hemorrhagic disease. Conventional view considered its pathogenesis as the destruction of platelets induced by platelet associated antibodies, the target of treatment are inhibiting the production of antibodies and blocking the destruction of platelets in reticuloendothelial system, but they are ineffective in part of ITP patients, who transform to chronic/refractory ITP (C/RITP). As to children's C/RITP, the effect of first-line therapy is low, while the second-line therapy isn't effective definitely and has obvious side effects. The safe and effective second-line drugs to prevent disease progressing are urgently required. Recently, a pathogenesis that decrease the platelet production has been confirmed, thrombopoietic drugs, including thrombopoietin (TPO) and its receptor agonist (TRA), are under research and clinical application gradually. Recombinate human TPO (rhTPO) has accomplished Phase III clinical trails in adult C/RITP and tumor children. The Phase III clinical trails of romiplostim and eltrombopag, as the representative of TRA, in adult C/RITP have been performed. There are also two clinical trails of TRA for children's C/RITP, the efficacy and safety have been approved, with the convenience for using. In pediatric population, they have a good clinical application. In this article the research and development of thrombopoietic drugs and their perspective in pediatric clinical use are reviewed.