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The biconcave shape and corresponding deformability of the human red blood cell (RBC) is an essential feature of its biological function. This feature of RBCs can be critically affected by genetic or acquired pathological conditions. In this review, we highlight new dynamic in vitro assays that explore various hereditary blood disorders and parasitic infectious diseases that cause disruption of RBC morphology and mechanics. In particular, recent advances in high-throughput microfluidic devices make it possible to sort/identify healthy and pathological human RBCs with different mechanobiological characteristics.

A family of amphiphilic cyclodextrins (6, 7) has been prepared through 6-S-alkylation (alkyl=n-dodecyl and n-hexadecyl) of the primary side and 2-O-PEGylation of the secondary side of alpha-, beta-, and gamma-cyclodextrins (PEG=poly(ethylene glycol)). These cyclodextrins form nonionic bilayer vesicles in aqueous solution. The bilayer vesicles were characterized by transmission electron microscopy, dynamic light scattering, dye encapsulation, and capillary electrophoresis. The molecular packing of the amphiphilic cyclodextrins was investigated by using small-angle X-ray diffraction of bilayers deposited on glass and pressure-area isotherms obtained from Langmuir monolayers on the air-water interface. The bilayer thickness is dependent on the chain length, whereas the average molecular surface area scales with the cyclodextrin ring size. The alkyl chains of the cyclodextrins in the bilayer are deeply interdigitated. Molecular recognition of a hydrophobic anion (adamantane carboxylate) by the cyclodextrin vesicles was investigated by using capillary electrophoresis, thereby exploiting the increase in electrophoretic mobility that occurs when the hydrophobic anions bind to the nonionic cyclodextrin vesicles. It was found that in spite of the presence of oligo(ethylene glycol) substituents, the beta-cyclodextrin vesicles retain their characteristic affinity for adamantane carboxylate (association constant K(a)=7.1 x 10(3) M(-1)), whereas gamma-cyclodextrin vesicles have less affinity (K(a)=3.2 x 10(3) M(-1)), and alpha-cyclodextrin or non-cyclodextrin, nonionic vesicles have very little affinity (K(a) approximately 100 M(-1)). Specific binding of the adamantane carboxylate to beta-cyclodextrin vesicles was also evident in competition experiments with beta-cyclodextrin in solution. Hence, the cyclodextrin vesicles can function as host bilayer membranes that recognize small guest molecules by specific noncovalent interaction.

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High-mobility group box-1 (HMGB1) was originally identified as a ubiquitously expressed, abundant nonhistone DNA-binding protein. Recently, it was found to act as a cytokine-like mediator of delayed endotoxin lethality and of acute lung injury. Previously, we reported that HMGB1 is massively released extracellularly and plays a cytokine-like function in the postischemic brain. In the present study, we examined the expression profile and cellular distribution of HMGB1 in rat brain after transient focal cerebral ischemia. The expression of HMGB1 in infarction areas in the ipsilateral sides gradually declined over 2 days after 1 hr of middle cerebral artery occlusion (MCAO) to below the basal level. However, after 3 days of reperfusion, HMGB1 level increased to above the basal level, especially in infarction cores, and this delayed induction was then maintained for several days. Immunohistochemistry using a polyclonal antibody against HMGB1 revealed its detailed expression pattern and subcellular localization in the postischemic brain. HMGB1 was found to be widely expressed throughout the normal brain and to be localized to the nuclei of almost all neurons and oligodendrocyte-like cells. After 1 hr of MCAO, HMGB1 immediately translocated from the neuron nuclei to the cytoplasm and subsequently was depleted from neurons during the excitotoxicity-induced acute damaging process. Moreover, beginning 2 days after reperfusion, HMGB1 was notably induced in activated microglia, astrocytes, and in microvascular structures, and these delayed gradual inductions were sustained for several days. These findings suggest that HMGB1 functions as a cytokine-like mediator in a paracrine and autocrine manner in the postischemic brain.