Human B cells immortalized with Epstein-Barr virus upregulate CCR6 and CCR10 and downregulate CXCR4 and CXCR5

Compared to peripheral blood resting B cells, Epstein-Barr virus (EBV)-immortalized B cells consistently express CCR6 and CCR10 at high levels and CXCR4 and CXCR5 at low levels. Accordingly, these cells vigorously responded to the ligands of CCR6 and CCR10 but not to those of CXCR4 and CXCR5. In a human EBV-negative B-cell line, BJAB, stable expression of EBNA2 upregulated CCR6, while stable expression of EBNA2 as well as LMP1 downregulated CXCR4. On the other hand, upregulation of CCR10 or downregulation of CXCR5 was not induced in BJAB by stable expression of EBNA2 or LMP1. Thus, these changes may be due to a plasmablast-like stage of B-cell differentiation fixed by EBV immortalization. EBV-infected B cells in infectious mononucleosis are known to avoid germinal centers and accumulate under the mucosal surfaces. EBV-associated opportunistic lymphomas also tend to occur in extranodal sites. These preferred sites of in vivo localization are consistent with the unique profile of chemokine receptor expression exhibited by EBV-immortalized B cells.     

Studies on the generation of Ca2+/calmodulin-independent activity of calmodulin-dependent protein kinase II by autophosphorylation. Autothiophosphorylation of the enzyme.

The mechanism for the generation of the Ca2+/calmodulin (CaM)-independent activity of calmodulin-dependent protein kinase II (CaM-kinase II) by autophosphorylation was studied by characterizing the autothiophosphorylated enzyme, which is resistant to hydrolysis. When CaM-kinase II was incubated with adenosine 5'-O-(thiotriphosphate) at 5 degrees C, the incorporation of thiophosphate into the enzyme occurred rapidly, reaching a maximum level within a few minutes, in parallel with increase in Ca2+/CaM-independent activity. The maximum level was 1 mol of thiophosphate per mol of subunit of the enzyme, and the thiophosphorylation occurred exclusively at Thr286 in the alpha subunit and Thr287 in the other subunits of the enzyme. These results, taken together, indicate that the autothiophosphorylation of Thr286/Thr287 of each subunit is involved in the generation of the Ca2+/CaM-independent activity. The activity of the autothiophosphorylated enzyme, when assayed in the presence of Ca2+/CaM, showed the same kinetic properties as did the Ca2+/CaM-dependent activity of the original non-phosphorylated enzyme, but when assayed in the absence of Ca2+/CaM, it showed the same Vmax as the Ca2+/CaM-dependent activity but higher Km values for protein substrates. Thus, the phosphorylation of Thr286/Thr287 of the subunit of the enzyme by autophosphorylation appears to not only enhance the affinity of its substrate-binding site for the protein substrate, although it is lower than that of the enzyme activated by the binding of CaM, but also convert the active site to the fully active state.     

Influence of bile salts on β-glucuronidase activity of intestinal bacteria

T. FUJISAWA AND M. MORI. 1996. The β-glucuronidase activity of intact cells of Escherichia coli and Clostridium perfringens was increased in the presence of bile salts. In contrast, bile salts had inhibitory effects on the activity of β-glucuronidase extracted from the lysed cells. These results suggest that the permeability of the bacterial cells is increased by the presence of bile salts, and that bile salts may significantly enhance bacterial β-glucuronidase activity in the intestinal tract.     

Environmental control of collateral branching and target invasion of mitral cell axons during development

During development, mitral cell axons, the major efferents of the olfactory bulb, exhibit a protracted waiting period in the lateral olfactory tract (LOT) before giving off collateral branches and innervating the target olfactory cortex. To investigate the target invasion mechanism, a series of heterochronic and heterotopic cocultures of olfactory bulbs with various olfactory cortical strips were conducted. These experiments indicated that development of collateral branches is triggered by environmental cues but not by intrinsic mechanisms in mitral cells. The collateral-inducing cues are apparently different from the cues directing outgrowth of primary mitral cell axons. Coculture experiments also indicated that the target olfactory cortex undergoes a developmental change to become accessible to mitral cell fibers. Primary mitral cell axons, however, still preferred the LOT position over such accessible piriform cortex when encountered both the locations. These results suggest that mitral cell projection comprises multiple steps which are controlled by various environmental cues.     

A case of maxillary sarcoma in a chimpanzee (Pan troglodytes)

Oral malignancy is rare in chimpanzees. A 34‐year‐old female chimpanzee (Pan troglodytes) at Kumamoto Sanctuary, Japan, had developed it. Treatment is technically difficult for chimpanzees while malignant neoplasm is seemingly rising in captive populations. Widespread expert discussion, guidelines for treatment, especially for great apes in terminal stages is urgently needed.     

Computational chemical analysis of Ru(II)‐Pheox–catalyzed highly enantioselective intramolecular cyclopropanation reactions

Computational chemical analysis of Ru(II)‐Pheox–catalyzed highly enantioselective intramolecular cyclopropanation reactions was performed using density functional theory (DFT). In this study, cyclopropane ring–fused γ‐lactones, which are 5.8 kcal/mol more stable than the corresponding minor enantiomer, are obtained as the major product. The results of the calculations suggest that the enantioselectivity of the Ru(II)‐Pheox–catalyzed intramolecular cyclopropanation reaction is affected by the energy differences between the starting structures 5l and 5i . The reaction pathway was found to be a stepwise mechanism that proceeds through the formation of a metallacyclobutane intermediate. This is the first example of a computational chemical analysis of enantioselective control in an intramolecular carbene‐transfer reaction using C₁‐symmetric catalysts.     

Cumulative Incidence and Predictors of Progression in Corticosteroid-Na?ve Patients with Sarcoidosis

Background

Assessment of the clinical course of sarcoidosis requires long-term observation. However, the appropriate period of follow-up for sarcoidosis remains unclear, especially in patients without indication of corticosteroid therapy at the time of diagnosis.

Objective

This study aimed to clarify the cumulative incidence and identify risk factors for disease progression in corticosteroid-naïve sarcoidosis patients.

Methods

The clinical courses of 150 Japanese patients with sarcoidosis, who were followed for more than 2 years and had no indication for corticosteroid therapy at diagnosis, were retrospectively reviewed. Disease progression was defined as worsening of pulmonary sarcoidosis, development of new organ involvement, or extrapulmonary organ damage. The cumulative incidence of progression was estimated by generating a cumulative incidence curve with the Fine and Gray method.

Results

The median follow-up duration was 7.7 years (interquartile range, 4.7–13.6 years). Thirty-two (21%) patients experienced disease progression. New organ involvement appeared in 16 patients (11%). The 6-month, and 1-, 5-, 10-, and 15-year cumulative incidence of progression was 2%, 5%, 15%, 28%, and 31%, respectively. The number of organs involved at diagnosis was an independent predictor for progression with a multifactorial adjusted hazard ratio of 1.71 (95% confidence interval, 1.11–2.62). The optimal cut-off of the number of organs involved at diagnosis to identify future progression was three.

Conclusions

In corticosteroid-naïve sarcoidosis patients, the risks of disease progression are comparable from 0–5 years and 5–10 years after diagnosis. The number of organs involved at diagnosis is a useful predictor for progression of sarcoidosis.     

Phencyclidine animal models of schizophrenia: approaches from abnormality of glutamatergic neurotransmission and neurodevelopment

In humans, phencyclidine (PCP), a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist, reproduces a schizophrenia-like psychosis including positive symptoms, negative symptoms and cognitive dysfunction. Thus, the glutamatergic neuronal dysfunction hypothesis is one of the main explanatory hypotheses and PCP-treated animals have been utilized as an animal model of schizophrenia. The adult rodents treated with PCP repeatedly exhibit hyperlocomotion as an index of positive symptoms, a social behavioral deficit in a social interaction test and enhanced immobility in a forced swimming test as indices of negative symptoms. They also show a sensorimotor gating deficits and cognitive dysfunctions in several learning and memory tests. Some of these behavioral changes endure after withdrawal from repeated PCP treatment. Furthermore, repeated PCP treatment induces some neurochemical and neuroanatomical changes. On the other hand, the exposure to viral or environmental insult in the second trimester of pregnancy increases the probability of subsequently developing schizophrenia as an adult. NMDA receptor has been implicated in controlling the structure and plasticity of developing brain circuitry. Based on neurodevelopment hypothesis of schizophrenia, schizophrenia model rats treated with PCP at the perinatal stage is developed. Perinatal PCP treatment impairs neuronal development and induces long-lasting schizophrenia-like behaviors in adult period. Many findings suggest that these PCP animal models would be useful for evaluating novel therapeutic candidates and for confirming pathological mechanisms of schizophrenia.     

Evaluation of lipid‐binding properties of the N‐terminal helical segments in human apolipoprotein A‐I using fragment peptides

Although the N‐terminal region in human apolipoprotein (apo) A‐I is thought to stabilize the lipid‐free structure of the protein, its role in lipid binding is unknown. Using synthetic fragment peptides, we examined the lipid‐binding properties of the first 43 residues (1–43) of apoA‐I in comparison with residues 44–65 and 220–241, which have strong lipid affinity in the molecule. Circular dichroism measurements demonstrated that peptides corresponding to each segment have potential propensity to form α‐helical structure in trifluoroethanol. Spectroscopic and thermodynamic measurements revealed that apoA‐I (1–43) peptide has the strong ability to bind to lipid vesicles and to form α‐helical structure comparable to apoA‐I (220–241) peptide. Substitution of Tyr‐18 located at the center of the most hydrophobic region in residues 1–43 with a helix‐breaking proline resulted in the impaired lipid binding, indicating that the α‐helical structure in this region is required to trigger the lipid binding. In contrast, apoA‐I (44–65) peptide exhibited a lower propensity to form α‐helical structure upon binding to lipid, and apoA‐I (44–65/S55P) peptide exhibited diminished, but not completely impaired, lipid binding, suggesting that the central region of residues 44–65 is not pivotally involved in the formation of the α‐helical structure and lipid binding. These results indicate that the most N‐terminal region of apoA‐I molecule, residues 1–43, contributes to the lipid interaction of apoA‐I through the hydrophobic helical residues. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.     

Gibberellin Production in Cultured Cells of Nicotiana tabacum

Endogenous gibberellins (GAs) in several kinds of crown gallcells and cultured cells derived from normal tissue of Nicotianatabacum were systematically analyzed by gas chromatography-selectedion current monitoring (GC-SICM) after chromatographic purifications,and GA₁, GA₉, GA₁₉ and GA₂₀ were identified. Agrobacterium tumefaciens,a pathogen of crown gall, was confirmed not to produce GAs inits culture. We also investigated endogenous GAs of mother plant,tobacco, and found the same kinds of GAs as in cultured cells. ³ Present address: College of Agriculture, Chonnam NationalUniversity, Kwangju 500, Korea. (Received May 19, 1982; Accepted July 22, 1983)