Bronchoalveolar lavage cytokine profiles in acute asthma and acute bronchiolitis

BACKGROUND: The pathogenetic basis for the relationship between acute bronchiolitis and asthma has not yet been completely elucidated. OBJECTIVE: The aim of this study was to compare these 2 diseases in terms of their patterns of airway cytokine response (T(H)1 or T(H)2). METHODS: By using a bronchoalveolar lavage (BAL) technique, this study investigated the cytokine levels of BAL fluid in children with acute asthma who had no identifiable respiratory syncytial virus (RSV) infection (n = 18) and in infants with acute bronchiolitis caused by RSV (n = 22). Comparisons were made with normal control subjects (n = 14). IFN-gamma (T(H)1) and IL-4 and IL-5 (T(H)2) levels were measured in concentrated BAL fluids by means of ELISA. RESULTS: The IL-5 level (P <.001) and IL-5/IFN-gamma ratio (P <.001) were significantly increased in the asthmatic group with no identifiable RSV infection and in the RSV-induced bronchiolitis group compared with values in the control group. When infants in the bronchiolitis group were divided into eosinophil-positive and eosinophil-negative subgroups, the eosinophil-positive subgroup had significantly increased IL-5 levels (P <.001) and IL-5/IFN-gamma ratios (P <.01) compared with those in the control group, but similar cytokine responses were not induced in the eosinophil-negative subgroup. The percentage of BAL eosinophils correlated significantly with levels of BAL IL-5 in both the asthma group (r = 0.80, P =.000) and the bronchiolitis group (r = 0.82, P =.000). CONCLUSIONS: These findings suggest that a subgroup of the RSV-induced bronchiolitis group results in a T(H)2-type response, and this could provide a valuable framework to explain the link between RSV-induced bronchiolitis and asthma.     

Thymocyte-thymocyte interaction for efficient positive selection and maturation of CD4 T cells

Despite numerous reports on MHC class II expression by T cells from a wide spectrum of mammalian species including humans, the biological relevance of this phenomenon has never been tested with appropriately designed animal models. To address this issue, we developed mouse models in which immature thymocytes are the only positively selecting antigen-presenting cells in the thymus. In these mice, CD4+ T cells were generated with the appropriate maturation phenotype and showed a diverse repertoire of TCR Vbetas. The CD4+ T cells were functionally competent, mediating effective allogeneic responses that involved polyclonal TCR Vbetas. These results suggest that the thymocyte-thymocyte (T-T) interaction operates as an independent pathway for CD4+ T cell selection in the thymi of species with MHC II-positive thymocytes. This T-T interaction appears to be the basis for the generation of donor MHC-restricted CD4+ T cells in xenogeneic hosts.     

Modulation of large conductance calcium-activated K+ channel by membrane-delimited protein kinase and phosphatase activities

Large conductance Ca²⁺-activated K⁺ channel was identified and studied in excised inside-out membrane patches of freshly dispersed smooth muscle cells from rabbit gastric antrum. The current-voltage relationship of the single channel was linear from -80 to +80 mV of pipette voltage in which single channel conductance was 249±17.8 pS (n=19) in symmetrical concentration of K⁺ (145mM) across the patch. Activity of the channel (NPo) depended not only on cytoplasmic calcium concentration but also on membrane potential. MgATP increased NPo in a dose-dependent manner and Mg²⁺ was prerequisite for the effect. Okadaic acid (l00nM), inhibitor of protein phosphatases, increased NPo further in the presence of MgATP. Therefore, it would be concluded that activity of the calcium-activated K⁺ channel in gastric smooth muscle cells was controlled by phosphorylation state of the channel protein and the state is further modulated by membrane-delimited protein kinase and protein phosphatase activities.     

Epstein-Barr virus-associated smooth muscle tumor in patients with acquired immunodeficiency syndrome.

Epstein-Barr virus (EBV)-associated smooth muscle tumor (SMT) is a recognized but uncommon disease that is found to occur in patients with immunocompromised conditions such as acquired immunodeficiency syndrome (AIDS). These tumors may be multifocal and located at unusual sites, such as the brain and liver. This report describes the case of 2 AIDS patients with EBV-associated SMT and highlights the features and outcome of this rare but potentially important tumor in human immunodeficiency virus management.     

Expression of cell cycle regulators during smooth muscle cell proliferation after balloon catheter injury of rat artery

Intimal hyperplasia is defined as the abnormal migration and proliferation of vascular smooth muscle cells (VSMCs) with deposition of extracellular matrix. However, the cell cycle regulatory mechanisms of injury-induced VSMC proliferation are largely unknown. To examine the expression kinetics of cell cycle regulatory factors which is known to be worked positively or negatively, we used rat balloon injury model. Marked induction of proliferating cell nuclear antigen (PCNA), G1/S cyclin-dependent kinase (cdk2), and its regulatory subunit (cyclin E) occurred between 1 and 3 days after balloon arterial injury, and this was sustained for up to 7 days and then declined. However, the induction of the negative regulators, p21 and p27, occurred between 3 and 5 days of injury, peaked after 7 and 14 days and was then sustained. VSMC proliferation after balloon catheter injury of the rat iliac artery is associated with coordinated expression of positive (cdk2, cyclin E and PCNA) and negative (p21, p27) regulators. Cell cycle regulators such as cdk2, cyclin E, p21, p27 may be suitable targets for the control of intimal hyperplasia.     

Reactivity in radical and anionic copolymerizations of 4-(trimethylsilyl)styrene. Synthesis of soluble poly{(1,4-divinylbenzene)-co-[4-(trimethylsilyl)styrene]}

Radical copolymerization of 4-(trimethylsilyl)styrene (TMSS) with styrene were carried out to estimate the reactivity of TMSS. The monomer reactivity ratios r₁ and r₂ in the radical copolymerization of TMSS (M1) with styrene (M2) were evaluated as 0,28 and 0,48, respectively. The value r₁ · r₂ (= 0,13) being smaller than unity indicates that the trimethylsilyl group at para position behaves as an electron-withdrawing substituent. Reactions of lithium diethylamide with TMSS in the presence of diethylamine, gave the 1:1 addition product 1-[2-(N,N-diethylamino)-ethyl]-4-(trimethylsilyl)benzene. Kinetic analysis showed that the second-order rate constant (k) for this addition reaction is 34,4 · 10^?4 dm³ · mol^?1 · s^?1, which is by a factor of 2 larger than that for the reaction with styrene (k = 16,0 · 10^?4 dm³ · mol^?1 · s^?1). The fact is also compatible with the above consideration for the r₁ · r₂ values. Lithium diisopropylamide initiated anionic copolymerizations of TMSS with 1,4-divinylbenzene (DVB) were also examined. The polymerizations proceed smoothly without any gel formation and the resulting copolymers are soluble in various common solvents such as benszene, tetrahydrofuran, chloroform, etc. Thus, novel organosilicon-containing polymers having appropriate amounts of reactive pendent vinyl groups are easily synthesized.     

Molecular cloning and characterization of three beta-defensins from canine testes

Mammalian β-defensins are small cationic peptides possessing broad antimicrobial and physiological activities. Because dogs are particularly resilient to sexually transmitted diseases, it has been proposed that their antimicrobial peptide repertoire might provide insight into novel antimicrobial therapeutics and treatment regimens. To investigate this proposal, we cloned the full-length cDNA of three canine β-defensin isoforms (cBD-1, -2, and -3) from canine testicular tissues. Their predicted peptides share identical N-terminal 65-amino-acid residues, including the β-defensin consensus six-cysteine motif. The two longer isoforms, cBD-2 and -3, possess 4 and 34 additional amino acids, respectively, at the C terminus. To evaluate the antimicrobial activity of cBD, a 34-amino-acid peptide derived from the shared mature peptide region was synthesized. Canine β-defensin displayed broad antimicrobial activity against gram-positive bacteria (Listeria monocytogenes and Staphylococcus aureus; MICs of 6 and 100 μg/ml, respectively), gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, and Neisseria gonorrhoeae; MICs of 20 to 50, 20, and 50 μg/ml, respectively), and yeast (Candida albicans; MIC of 5 to 50 μg/ml) and lower activity against Ureaplasma urealyticum and U. canigenitalium (MIC of 200 μg/ml). Antimicrobial potency was significantly reduced at salt concentrations higher than 140 mM. All three canine β-defensins were highly expressed in testis. In situ hybridization indicated that cBD-1 was expressed primarily in Sertoli cells within the seminiferous tubules. In contrast, cBD-2 was located primarily within Leydig cells. The longest isoform, cBD-3, was detected in Sertoli cells and to a lesser extent in the interstitium. The tissue-specific expression and broad antimicrobial activity suggest that canine β-defensins play an important role in host defense and other physiological functions of the male reproductive system.     

Alterations in the INK4a/ARF locus and their effects on the growth of human osteosarcoma cell lines

Two different proteins, p16(INK4a) and p14(ARF), encoded by the INK4a/ARF locus play important roles in the RB and p53 pathways, respectively. This study was performed to determine genetic and epigenetic alterations in the INK4a/ARF locus and their effects on the growth of osteosarcoma. Among six cell lines examined, both p16(INK4a) and p14(ARF) exons were homozygously deleted in two cell lines, MG63 and HOS, and both p16(INK4a) and p14(ARF) promoters were methylated in one cell line, U2OS. Wild-type mRNA and proteins for p16(INK4a) and p14(ARF) were expressed in three other cell lines, SaOS2, HuO9, and G292. Transfection studies were performed using two cell lines, U2OS and MG63. Both the RB and p53 genes were wild types in U2OS, whereas p53 but not RB was mutated in MG63. Both p16(INK4a) and p14(ARF) suppressed the growth of U2OS, whereas p16(INK4a) but not p14(ARF) suppressed the growth of MG63. p53 only did not suppress the growth of MG63 either; however, coexpression of p14(ARF) with p53 increased the fraction of the G0/G1 phase in MG63 cells. The data presented here demonstrate the importance of genetic and epigenetic alterations in the INK4a/ARF locus for the growth of osteosarcoma and thus will be useful to further understand the biologic behavior of osteosarcoma in association with the defects in the p53 and RB pathways.     

Altered expression of G1 regulatory proteins in human soft tissue sarcomas

CONTEXT: Soft tissue sarcomas constitute a heterogeneous group of tumors for which tumorigenesis is not fully understood. Altered cell-cycle regulation may underlie the development and/or progression of human malignancies. However, data concerning the occurrence of cell-cycle aberrations in soft tissue sarcomas are very limited. OBJECTIVES: To detect the abnormal features of cell-cycle regulatory proteins in soft tissue sarcomas and to determine the potential role of these proteins in clinical behavior. DESIGN: The p53 and Rb-cyclin D pathways were investigated by immunohistochemical studies of p53, mdm2, pRb, p16, cyclin D1, and cdk4 proteins, respectively. RESULTS: Of the 67 sarcomas analyzed, nuclear accumulation of p53 was detected in 25 samples (37%), and overexpression of mdm2 was found in 16 samples (24%). Both p53 and mdm2 expression correlated with tumor grade. Abnormalities involving the Rb-cyclin D pathway were identified in all of the tumors by the altered expression of either pRb (72%) or p16 (94%). Fourteen (21%) and 64 (96%) cases demonstrated cyclin D1 or cdk4 expression, respectively. Overexpression of cyclin D1 showed an association with pRb and p53. There was no correlation between pRb, p16, cyclin D1, or cdk4 and tumor grade or relapse. CONCLUSION: Disturbance in the cell-cycle regulatory system involving the p53 pathway and the Rb-cyclin D pathway is relatively frequent in soft tissue sarcomas and may be a contributing factor in the tumorigenesis of these tumors. The alterations in the Rb-cyclin D pathway probably constitute an early event, whereas the abnormalities in the p53 pathway seem to be involved in tumor progression. It is noteworthy that cyclin D1 may play a key role in linking both pathways.