Graft Versus Host Disease with Mixed Chimerism

We report a patient with graft versus host disease (GVHD) with mixed chimerism (MC). The patient had chronic myelogenous leukemia and received bone marrow transplantation (BMT) from his elder sister. Eighty days after BMT, erythematous lesions appeared on his chest. Histological examination from the skin lesion revealed lymphocytic infiltration into the upper dermis. Eosinophilic necrotic keratinocytes were scattered through the epidermis. Liquefaction degeneration was also recognized. Sicca syndrome appeared from 110 days after BMT. Detection of host origin Y-chromosome-specific DNA by polymerase chain reaction (PCR) method in bone marrow and peripheral blood showed that all bone marrow samples obtained 6 months from BMT were positive for Y-specific DNA, while peripheral blood became positive in the 60th month after BMT. The host origin normal karyotype (46,XY) in the bone marrow samples was identified for the first time in the 60th month after BMT. These results indicate that host-origin hematopoietic cells survived after BMT.     

Autoantibodies to the heat-shock protein hsp90 in systemic lupus erythematosus

Patients with systemic lupus erythematosus (SLE) develop multiple autoantibodies to self-antigens. Analysis of autoantibody systems in this and related autoimmune disorders can provide information of etiologic and pathogenetic significance. We report here a previously unrecognized autoantibody to the 90,000-D heat-shock protein, hsp90, a molecule thought to have important functions in the cellular response to stress, virus-induced transformation, steroid hormone receptor action, and cellular activation. Autoantibodies to hsp90 were exclusively of the IgG class, and were detected in approximately 50% of unselected patients with SLE and 2/6 patients with idiopathic polymyositis. Anti-hsp90 antibodies were not detected in sera from 10 normal subjects, 10 patients with rheumatoid arthritis, or 7 patients with scleroderma. The identity of this major intracytoplasmic antigen was established by its specific removal from nonionic detergent cell lysates following immunoabsorption with monospecific rabbit anti-hsp90, and by demonstration of increased synthesis following a 10-min 45 degrees C heat shock. These data define the frequent occurrence of a novel autoantibody to a major heat-shock protein in patients with SLE.     

Phosphorylation of Ser-3 of cofilin regulates its essential function on actin

Background: Cofilin is a low-molecular weight actin-modulating protein, and is structurally and functionally conserved in eucaryotes from yeast to mammals. The functions of cofilin appear to be regulated by phosphorylation and dephosphorylation. Results: A proteolytic study of phosphorylated porcine cofilin and expression of a mutated cofilin in cultured cells revealed that Ser-3 is the unique phosphorylation site. Phosphorylated cofilin was found not to bind to either F-or G-actin while unphosphorylated cofilin binds to both. S3D-cofilin, in which Ser-3 was replaced with Asp, did not bind in vitro to actin while S3A-cofilin did. The transient overexpression of wild-type or S3A-cofilin in cultured cells caused disruption of pre-existing actin structures and induced cytoplasmic actin bundles. Heat shock-induced nuclear or NaCl buffer-induced cytoplasmic actin/cofilin rods contained the expressed cofilin. In contrast, the overexpression of S3D-cofilin did not alter the actin structures. Induced actin rods did not contain S3D-cofilin. S3D-porcine cofilin did not complement the lethality associated with Δcof1 mutations in Saccharomyces cerevisiae while wild-type and S3A-cofilin did. Furthermore, we found that S2A/S4D- and S2D/S4D-yeast cofilin mutants were not viable. Conclusion: We conclude that the function of cofilin is negatively regulated in vivo by phosphorylation of Ser-3 and that cells require the functions of unphosphorylated cofilin for viability.     

Phosphorylation of cofilin by LIM-kinase is necessary for semaphorin 3A-induced growth cone collapse

Semaphorin 3A is a chemorepulsive axonal guidance molecule that depolymerizes the actin cytoskeleton and collapses growth cones of dorsal root ganglia neurons. Here we investigate the role of LIM-kinase 1, which phosphorylates an actin-depolymerizing protein, cofilin, in semaphorin 3A-induced growth cone collapse. Semaphorin 3A induced phosphorylation and dephosphorylation of cofilin at growth cones sequentially. A synthetic cell-permeable peptide containing a cofilin phosphorylation site inhibited LIM-kinase in vitro and in vivo, and essentially suppressed semaphorin 3A-induced growth cone collapse. A dominant-negative LIM kinase, which could not be activated by PAK or ROCK, suppressed the collapsing activity of semaphorin 3A. Phosphorylation of cofilin by LIM-kinase may be a critical signaling event in growth cone collapse by semaphorin 3A.     

Exogenous antigens are processed through the endoplasmic reticulum-associated degradation (ERAD) in cross-presentation by dendritic cells

Antigen cross-presentation is critical in infectious and tumor immunity where cytotoxic T lymphocytes are induced by dendritic cells specifically equipped with cellular machineries to present exogenous antigens with major histocompatibility complex (MHC) class I molecules. To examine molecular mechanisms of antigen cross-presentation, we employed as a model system a murine dendritic cell line DC2.4 capable of presenting soluble antigens such as ovalbumin (OVA) with MHC class I. Here, we demonstrate that exogenously added OVA is accumulated in the endoplasmic reticulum (ER) and late endosomes followed by retrograde transport to the cytoplasm through the Sec61 transporter complexes, and that CHIP functions as an E3 ubiquitin-ligase for OVA degradation by proteasomes. This mechanism is essentially the same as that known as the ER-associated degradation (ERAD) in the quality control of secretary and membrane proteins.     

The pathogenesis of hyaline globules in liver cells after partial hepatectomy in rats

To clarify the pathogenesis of hyaline globules in liver cells after partial hepatectomy, the present study was undertaken in rats. When partial hepatectomy was performed by the surgical procedure of Higgins and Anderson, the inferior vena cava pressure was raised, and many hyaline globules, which are very similar to those caused by condensation of the contents of vacuoles in liver cells after temporary pressure elevation of the inferior vena cava, were induced in liver cells. On the other hand, when the median lobe and the left lateral lobe were removed carefully one at a time to avoid operative narrowing of the inferior vena cava, the inferior vena cava pressure was not elevated, and only very few hyaline globules were formed. This suggests that hyaline globules in liver cells following partial hepatectomy in rats may be caused by elevation of inferior vena cava pressure due to narrowing of the inferior vena cava by surgical procedure.     

Degradation of ginseng saponins under mild acidic conditions

Ginseng saponins, ginsenosides Rg (1), Re and Rb (1), decomposed under mild acidic conditions to yield prosapogenins. The structures of the prosapogenins were investigated by (13)C-NMR spectroscopy and Rg (1)-prosapogenin II was shown to be a mixture of ginsenoside Rh (1), and its C-20 epimer, produced by hydrolysis followed by epimerization at C-20. Rg (1)-prosapogenin III, the other prosapogenin derived from ginsenoside Rg (1); was a C-25,26 hydrated derivative of Rg (1)-prosapogenin II. Re-prosapogenin II was identified as a mixture of ginsenoside Rg (2) and its C-20 epimer, and Re-prosapogenine III as a C-25,26 hydrated derivative of Re-prosapogenin II.     

Primary intracerebral and aneurysmal subarachnoid hemorrhage in Izumo City, Japan. Part I: incidence and seasonal and diurnal variations

OBJECT: The purpose of this community-based study was first to estimate the incidence rates of primary intracerebral hemorrhage (ICH) and aneurysmal subarachnoid hemorrhage (SAH) in Izumo City, Japan, and second to investigate whether there were seasonal and diurnal periodicities in their onset. METHODS: During 1991 through 1996, 267 patients with primary ICH and 123 with aneurysmal SAH were treated in Izumo City. The crude and the age- and sex-adjusted annual incidence rates per 100,000 population for all ages were 52 and 48 for ICH and 24 and 23 for SAH, respectively. These incidence rates were higher than those previously published for any other geographical region. The incidence rates of both ICH and SAH increased almost linearly with age. For ICH, a significant seasonal pattern was observed in men and in patients younger than 65 years, with a peak in winter and a trough in summer. However, no significant seasonal fluctuation was found in women or in individuals aged 65 years or older. There was no significant seasonal periodicity for SAH, even when patients were analyzed according to sex and age. Diurnal variations in the onset of both ICH and SAH were significant (except in men with SAH), with a nadir between midnight and 6:00 a.m. CONCLUSIONS: The actual incidence rates of both primary ICH and aneurysmal SAH seem to be much higher than have been reported so far. In addition, the data indicate the existence of seasonal periodicity for men and younger patients with ICH, and that the risk of both ICH and SAH is lower during nighttime.