Post-transfusion purpura: a heterogeneous syndrome

Three new patients with post-transfusion purpura (PTP) are described. As the manifestations in two differ significantly from those of previously reported cases, they serve to expand the definition of this syndrome. Although all 14 previously reported cases have occurred in Pl- A1-negative females, one of our patients was a Pl-A-negative male. Moreover, a female whose postrecovery platelets possessed the Pl-A1 antigen is described. Antiplatelet antibody activity was detected in all three patients by the 51Cr release test; in contrast, only one reacted in the complement (C) fixation assay. Serum obtained during the acute episode from the PlA1-positive patient reacted against platelets from four of 11 normals by C fixation and against platelets from 48 of 53 normals by 51Cr release, including five of nine Pl-A1-negative platelet samples. This case represents the first instance of PTP in which the platelet isoantibody was not specifically directed against the Pl-A1 antigen. These observations suggest that PTP may be a more heterogeneous disorder than previously realized.     

Discrimination of normal and abnormal prothrombin and protein C in plasma using a calcium ion-inhibited monoclonal antibody to a common epitope on several vitamin K-dependent proteins

Vitamin K deficiency or administration of vitamin K antagonists results in the biosynthesis of abnormal des-gamma-carboxy forms of the vitamin K-dependent proteins. Monoclonal antibody H-11 binds several vitamin K- dependent proteins at a determinant that includes the first two residues of gamma-carboxyglutamic acid. Antibody H-11 binds fully carboxylated prothrombin and protein C in the presence of EDTA but binding is inhibited by the divalent metal ions, calcium, magnesium, and manganese. By contrast, des-gamma-carboxy prothrombin and protein C bind antibody H-11 the same in the presence of EDTA or calcium ion. Antibody H-11 thus appears to bind a conserved antigenic site containing gamma-carboxyglutamic acid that in the presence of divalent metal ion undergoes a conformational transition. This ability of antibody H-11 to bind des-gamma-carboxy prothrombin and protein C in the presence of calcium ion allowed the development of an immunoassay for these proteins in plasma. Prothrombin and protein C from stably anticoagulated individuals receiving warfarin were characterized by their ability to bind antibody H-11 in the presence of calcium ion. Binding of prothrombin and protein C to antibody H-11 in the presence of calcium correlated temporally with warfarin administration. The inability of calcium ion to inhibit binding of antibody H-11 to abnormal prothrombin and protein C in plasma suggests that the circulating forms of both proteins following warfarin administration cannot undergo the metal ion-dependent conformational transition that includes sequence residues 1 through 12.     

Frontier performance of in situ formed α-MnO2 dispersed over functionalized multi-walled carbon nanotubes covalently anchored to a graphene oxide nanosheet framework as supercapacitor materials

α-MnO₂ has been recognized as a potential material for supercapacitor applications because of its abundance, cost-effectiveness, environmental-benign nature and high theoretical specific capacitance (C_sp) of 1370 F g⁻¹. In this study, we succeeded for the first time to achieve the theoretical C_sp with 3D multi-walled carbon nanotubes (MWCNTs) horizontally dispersed on 2D graphene oxide (GO) nanosheet framework-supported MnO₂ ternary nanocomposites synthesized by a simple precipitation method. The in situ formation of α-MnO₂ and GO, and the growth of 3D MWCNT/GO framework took place simultaneously in a strong acidic suspension containing functionalized-MWCNTs, graphite, NaNO₃ and KMnO₄. Characterizations of the composites synthesized by varying % wt MWCNTs were performed with state-of-the-art techniques. These composites were characterized to be semi-crystalline and mesoporous in nature, and the scrupulous analyses of field emission scanning electron microscopic images showed MnO₂ nano-flower distributed over 3D MWCNTs dispersed-on-GO-nanosheet frameworks. These composites deposited on a graphite electrode exhibited an ideal supercapacitive behavior in an Na₂SO₄ solution measured via cyclic voltammetry and chronopotentiometry. Optimum contents of MnO₂ and MWCNTs in the composites showed a maximum C_sp of 1380 F g⁻¹ with satisfactory energy and power densities compared in the Ragone plot. An ascending trend of C_sp against the charge–discharge cycle number studied for 700 cycles was noticed. Well-dispersion of α-MnO₂ nanoparticles throughout 3D MWCNTs covalently-anchored to the GO nanosheet framework is discussed to aid in achieving the frontier C_sp of MnO₂.

Achieving the milestone of theoretical capacitance of α-MnO₂ dispersed over 3D multi-walled carbon nanotubes anchored to a graphene oxide nanosheet framework.     

甲基莲心碱对豚鼠心房生理特性及异丙肾上腺素和Ca2+量—效反应的影响

甲基莲心碱1～100μmol/L浓度依赖性地抑制豚鼠左心房收缩性,延长功能性不应期,降低兴奋性;30μmol/L甲基莲心碱能明显提高肾上腺素诱发左心房自律性的阈浓度。对异丙肾上腺素量—效反应的影响,不同于β-受体阻滞剂普萘洛尔,表现为非竞争性拮抗作用,对Ca²⁺量—效反应的影响,与抗钙剂维拉帕米类似,呈竞争性和非竞争性双重拮抗作用。     

Grade I hydronephrosis: pulsed Doppler US evaluation

This study was undertaken to determine whether the presence of blood vessels could mimic the appearance of grade I hydronephrosis on sonograms and thus cause false-positive readings. One hundred consecutive patients with grade I hydronephrosis were examined. Sample volumes were obtained with pulsed Doppler ultrasonography (US) at the site of the greatest separation of the central renal sinus echoes to determine if the separation was fluid accumulating in the collecting system, as in obstruction, or if the separation was actually caused by vessels that mimic hydronephrosis. Vascular structures accounted for the separation of the sinus echoes in 43% of patients. In patients 12 years of age or younger, this frequency rose to 61%. The simple procedure of evaluating the renal sinus echo separation with pulsed Doppler US should decrease the frequency of false-positive diagnoses of hydronephrosis and thus diminish the need for further confirmatory testing.