Persistent serpentine supravenous hyperpigmented eruption associated with docetaxel

Various mucocutaneous reactions have been reported with the use of systemic docetaxel. We describe a 47-year-old man who developed a persistent serpentine supravenous hyperpigmented eruption (PSSHE), beginning at the site of docetaxel injection and spreading along the superficial venous network in the anterior aspect of the right forearm and distal arm. The eruption occurred after the first infusion of docetaxel following insufficient venous washing. A second infusion was administered through a vein in the other forearm, but this time, abundant venous washing was performed and a similar eruption did not occur. To our knowledge, this is the second report of docetaxel-induced supravenous discoloration and we discussed the terminology and mechanism of this unique reaction.     

The use of Terson lens capsule forceps when performing punch biopsy of the skin

When performing skin biopsy using the skin biopsy punch, it is recommended that Terson lens capsule forceps be used as an aid to avoid crush artifact. This is because secure yet gentle purchase of the specimen is allowed by a row of small inwardly directed tines that arise from the 2.5 mm horizontally placed grasping blades, which are inserted into the incision created by a 3mm biopsy punch. The instrument also has the extra advantages of being in the correct working position when held with the hand in the resting position between prone and supine, of allowing an uninterrupted line of vision to the wound during use and is of a shape that minimizes unintentional contact with tissue.     

优秀女子赛艇运动员比赛前后血乳酸、血尿素及血清肌酸激酶跟踪测试

目的:跟踪测试优秀女子赛艇运动员比赛前后血乳酸、血尿素及血清肌酸激酶的变化,探讨女子赛艇运动员机体能量物质代谢和赛后疲劳恢复的特点。方法:选取2005-07/09湖北省水上运动中心优秀女子运动员14名,其中国家健将级运动员7名,国家一级运动员7名;平均年龄(22±4)岁,训练年限(4.1±1.4)年,身高(174.2±3.1)cm,体质量(68.6±4.7)kg。14名运动员分别于2000m划艇比赛当日晨空腹、赛前15min、赛后5min,1h及24h抽取指尖血60μL,进行血乳酸、血尿素、血清肌酸激酶检测。结果:14名运动员全部进入结果分析。①比赛前后运动员血乳酸水平的变化:运动员空腹血乳酸水平为(1.22±0.45)mmol/L,赛前15min为(2.89±0.49)mmol/L。赛后5min血乳酸浓度高达(11.51±1.72)mmol/L,与空腹水平比较差异有显著性意义(t=3.077,P<0.01)。赛后24h血乳酸浓度显著下降至(1.76±0.24)mmol/L,与空腹水平基本接近(t=0.027,P>0.05)。②比赛前后运动员血尿素水平的变化:与空腹血尿素水平比较,运动员赛后5min血尿素浓度明显升高[(5.45±0.47),(6.13±1.00)mmol/L;t=2.416,P<0.05]。赛后24h血尿素浓度下降至(5.94±0.85)mmol/L,仍高于空腹水平(t=2.682,P<0.05)。③比赛前后运动员血清肌酸激酶活性的变化:与赛前比较,运动员赛后5min血清肌酸激酶活性明显升高[(3.38±1.58),(6.13±3.25)nkat/L;t=4.968,P<0.01]。赛后1h血清肌酸激酶活性开始下降,至赛后24h与赛前基本相似(t=1.537,P>0.05)。结论:①赛后5min血乳酸、血尿素、血清肌酸激酶活性显著高于赛前,赛后1h血乳酸消除迅速,但仍未恢复到正常水平。提示赛艇是一种以糖酵解系统为主、无氧 有氧代谢混合型供能的运动项目。②赛艇比赛使酸性产物生成增多,血乳酸、血尿素、血清肌酸激酶可作为运动强度和机能恢复的指标。③赛艇比赛后至少24h内,机体处于蛋白质降解增强状态,建议恢复期增加饮食糖和蛋白质摄入量,以促进合成代谢,加快功能恢复过程。     

Nanomechanics and intermolecular forces of amyloid revealed by four-dimensional electron microscopy

The amyloid state of polypeptides is a stable, highly organized structural form consisting of laterally associated β-sheet protofilaments that may be adopted as an alternative to the functional, native state. Identifying the balance of forces stabilizing amyloid is fundamental to understanding the wide accessibility of this state to peptides and proteins with unrelated primary sequences, various chain lengths, and widely differing native structures. Here, we use four-dimensional electron microscopy to demonstrate that the forces acting to stabilize amyloid at the atomic level are highly anisotropic, that an optimized interbackbone hydrogen-bonding network within β-sheets confers 20 times more rigidity on the structure than sequence-specific sidechain interactions between sheets, and that electrostatic attraction of protofilaments is only slightly stronger than these weak amphiphilic interactions. The potential biological relevance of the deposition of such a highly anisotropic biomaterial in vivo is discussed.The intricate interplay of intermolecular forces stabilizing amyloid at the atomic level has yet to be fully elucidated (1). Amyloid fibrils are narrow (70–200 Å), elongated (1–3 μm), twisted (pitch  ～  1,000 ± 500 Å) aggregates containing a universal “cross-β” core structure (2) composed of arrays of β-sheets running parallel to the long axis of the fibrils (3). Their hierarchical structure is stabilized by three main protein–protein interfaces: (i) stacking of hydrogen-bonded β-strands within a single β-sheet (intrasheet), (ii) cross-β-sheet packing into a multisheet protofilament (intersheet), and (iii) lateral association of protofilaments (interprotofilament) (4). Each of these packing interfaces gives rise to characteristic diffraction pattern reflections corresponding to the intrasheet (4.8 Å), intersheet (8–12 Å, depending on sidechain volume), and interprotofilament (determined by chain length) spacings (5).By applying a laser-induced, temperature (T-) jump to amyloid, we can infinitesimally expand the material, thereby probing the intermolecular forces acting across each of the packing interfaces (6). Static, global heating, particularly of amyloid-like microcrystals (7), disrupts molecular structure, precluding such delicate perturbations. To capture the rapid expansion and recovery of an amyloid specimen, a precisely timed, pulsed (probe) electron beam, following the laser (pump) pulse, is used to generate a series of time-resolved diffraction patterns. By accurately measuring the movement (Δx) of the reflection (initially occurring at an equilibrium separation, x_e) upon initiation of the ultrafast temperature jump, we determine the relative expansion, or strain, ? = Δx/x_e. Atomistic simulations predict that the stretching elasticity of amyloid is linear for strains up to only ? ～ 0.1%, i.e., 10^?3 (8). The exquisite sensitivity and high spatiotemporal resolution of four-dimensional (4D) electron microscopy (9, 10) enables us to measure such minute deformations and directly probe, at the atomic level, the stiffness of the intermolecular forces stabilizing amyloid.     

Preparation of factor IX deficient human plasma by immunoaffinity chromatography using a monoclonal antibody

A murine hybridoma clone is described that grows continuously in culture and produces a monoclonal antibody we have called Royal Free Monoclonal Antibody to factor IX No. 1 (RFF-IX/1). This has high affinity for a coagulation site on factor IX. RFF-IX/1 immobilised on sepharose can be used to deplete factor IX from normal human plasma. This immunoaffinity depleted plasma is indistinguishable from severe Christmas disease plasma and can be used as the substrate in a one stage coagulation assay for factor IX. The affinity column has high capacity and can be regenerated so that large scale production from normal plasma of factor IX deficient plasma as a diagnostic reagent is now feasible.     

High-molecular-weight kininogen is exclusively membrane bound on endothelial cells to influence activation of vascular endothelium

An important biologic function of high-molecular-weight kininogen (HK) is to deliver bradykinin (BK) to its cellular receptors. Internalization and degradation of HK may provide a mechanism by which endothelial cells modulate the production of BK and control its activities. Therefore, we investigated the binding and subsequent distribution of biotinylated-HK (biotin-HK) associated with human umbilical vein endothelial cells (HUVEC). HUVEC bound 3 to 4 times more HK and with greater avidity at 1 to 3 hours at 37 degrees C than at 4 degrees C (Bmax = 1.0 +/- 0.02 x 10(7) molecules/cell, kd = 7 +/- 3 nmol/L v Bmax = 2.6 +/- 0.2 x 10(6) molecules/cell, kd = 46 +/- 8 nmol/L). However, there was no evidence that the difference was caused by internalization of HK at the higher temperature. First, the same amount of biotin-HK was associated with nonpermeabilized and permeabilized HUVEC using buffers containing 20 to 50 mumol/L zinc ion in the absence or presence of 2 mmol/L calcium ion. Second, binding of biotin-HK to HUVEC was approximately 92% reversible at 1 hour when the cells were maintained at both 37 degrees C and 4 degrees C. Third, neither chloroquine nor primaquine altered the amount of biotin-HK bound to HUVEC. Fourth, biotin-HK bound to HUVEC was almost completely removed by pronase. Fifth, the nonpermeable dye, crystal violet, almost completely quenched the fluorescence signal emitted by HUVEC-associated fluorescein isothiocyanate (FITC) HK. Finally, the localization of HUVEC-bound FITC-HK was restricted to the membrane as shown by laser scanning confocal microscopy. The expression of HK binding sites had an absolute requirement for metabolic energy, but was not dependent on new protein synthesis. Membrane-bound HK contributed to the anticoagulant nature of endothelial cells by blocking human alpha-thrombin binding and its resultant induction of prostacyclin formation. These studies indicate that HK is not internalized by HUVEC, but remains primarily on cell surfaces to be accessible for BK liberation and to modulate the binding and actions of alpha-thrombin.     

High molecular weight kininogen: localization in the unstimulated and activated platelet and activation by a platelet calpain(s)

High mol wt kininogen (HMWK), the major cofactor-substrate of the contact phase of coagulation, is contained within and secreted by platelets. Studies have been performed to localize platelet HMWK in both the unstimulated and activated platelet and to ascertain the effect of platelet enzymes on HMWK itself. On platelet subcellular fractionation, platelet HMWK was localized to alpha-granules, and platelets from a patient with a deficiency of these granules (gray platelet syndrome) had 28% normal platelet HMWK. Platelet HMWK, in addition to being secreted from the platelet, was also localized to the surface of the platelet when activated. Using a competitive enzyme- linked immunosorbent assay for HMWK as an indirect antibody consumption assay, the external membrane of thrombin-activated platelets as well as the releasate from these stimulated platelets had 17 ng HMWK antigen/10(8) platelets available, whereas unstimulated platelets and their supernatant had only 4.9 and 4.2 ng HMWK/10(8) platelets present, respectively. The anti-HMWK antibody consumption by activated normal platelets was specific for membrane-expressed platelet HMWK, since activated platelets from a patient with total kininogen deficiency did not adsorb the anti-HMWK antibody. Enzymes in the cytosolic fraction of platelets cleaved 125I-HMWK (mol wt 120,000) into a mol wt 100,000 polypeptide as well as smaller products at mol wt 74,000, mol wt 62,000, mol wt 47,000, and a few components below mol wt 45,000. No cleavage products were observed when DFP and leupeptin were present. The cleavage of HMWK was specifically prevented by inhibitors of calcium-activated cysteine proteases (leupeptin, N-ethylmaleimide, iodoacetamide, and EDTA) but not by inhibitors of serine proteases (DFP, benzamidine, soybean trypsin inhibitor, or aprotinin). Platelet cytosol increased the coagulant activity of exogenous purified HMWK with maximum HMWK coagulant activity (35-fold) occurring within ten minutes of exposure to platelet cytosol. Treatment of platelet cytosol with leupeptin prevented the increase in the coagulant activity of exogenous HMWK. These studies indicate that activated platelets express platelet HMWK on their external membrane and platelet enzymes can cleave and increase the coagulant activity of exogenous HMWK.     

Ultrafast diffraction and structural dynamics: the nature of complex molecules far from equilibrium

Studies of molecular structures at or near their equilibrium configurations have long provided information on their geometry in terms of bond distances and angles. Far-from-equilibrium structures are relatively unknown-especially for complex systems-and generally, neither their dynamics nor their average geometries can be extrapolated from equilibrium values. For such nonequilibrium structures, vibrational amplitudes and bond distances play a central role in phenomena such as energy redistribution and chemical reactivity. Ultrafast electron diffraction, which was developed to study transient molecular structures, provides a direct method for probing the nature of complex molecules far from equilibrium. Here we present our ultrafast electron diffraction observations of transient structures for two cyclic hydrocarbons. At high internal energies of approximately 4 eV, these molecules display markedly different behavior. For 1,3,5-cycloheptatriene, excitation results in the formation of hot ground-state structures with bond distances similar to those of the initial structure, but with nearly three times the average vibrational amplitude. Energy is redistributed within 5 ps, but with a negative temperature characterizing the nonequilibrium population. In contrast, the ring-opening reaction of 1,3-cyclohexadiene is shown to result in hot structures with a CC bond distance of over 1.7 A, which is 0.2 A away from any expected equilibrium value. Even up to 400 ps, energy remains trapped in large-amplitude motions comprised of torsion and asymmetric stretching. These studies promise a new direction for studying structural dynamics in nonequilibrium complex systems.