Effect of high NaCl intake on Na+ and K+ transport in the rabbit distal convoluted tubule

Morphological studies have demonstrated that a chronic increase in distal Na⁺ delivery causes hypertrophy of the distal convoluted tubule (DCT). To examine whether high NaCl-intake also causes functional changes in the well defined DCT, we measured transmural voltage (V _T), lumen-to-bath Na⁺ flux (J _Na(LB)), and net K⁺ secretion (J _K(net)) in DCTs obtained from control rabbits and those on high NaCl-intake diets. The lumen negativeV _T was significantly greater in the high NaCl group than in the control group. The net K⁺ secretion (pmol mm^–1 min^–1) was greater in the high NaCl-intake group (54.1±13.0 vs 14.7±5.6). The K⁺ permeabïlities in both luminal and basolateral DCT membranes, as assessed by the K⁺-induced transepithelial voltage deflection inhibitable with Ba²⁺, were increased in the experimental group. The lumen-to-bath²²Na flux (pmol mm^–1 min^–1) was also greater in the experimental group (726±119 vs 396±65). TheV _T component inhibitable with amiloride was also elevated in the high NaCl-intake group. Furthermore, Na⁺–K⁺-ATPase activity of the DCT was higher in the experimental than in the control group. We conclude that high NaCl intake increases both Na⁺ reabsorption and K⁺ secretion by the DCT. This phenomenon is associated with an increased Na⁺–K⁺-ATPase activity along with increased Na⁺ and K⁺ permeabilities of the luminal membrane, and an increase in the K⁺ permeability of the basolateral membrane. Cellular mechanisms underlying these functional changes remain to be established.     

Lectin histochemical study on the olfactory organ of the newt,Cynops pyrrhogaster,revealed heterogeneous mucous environments in a single nasal cavity

Expression patterns of glycoconjugates were examined by lectin histochemistry in the nasal cavity of the Japanese red-bellied newt, Cynops pyrrhogaster. Its nasal cavity consisted of two components, a flattened chamber, which was the main nasal chamber (MNC), and a lateral diverticulum called the lateral nasal sinus (LNS), which communicated medially with the MNC. The MNC was lined with the olfactory epithelium (OE), while the diverticulum constituting the LNS was lined with the vomeronasal epithelium (VNE). Nasal glands were observed beneath the OE but not beneath the VNE. In addition, a secretory epithelium was revealed on the dorsal boundary between the MNC and the LNS, which we refer to as the boundary secretory epithelium (BSE) in this study. The BSE seemed to play an important role in the construction of the mucous composition of the VNE. Among 21 lectins used in this study, DBA, SBA and Jacalin showed different staining patterns between the OE and the VNE. DBA staining showed remarkable differences between the OE and the VNE; there was intense staining in the free border and the supporting cells of the VNE, whereas there was no staining or weak staining in the cells of the OE. SBA and Jacalin showed different stainings in the receptor neurons for the OE and the VNE. Furthermore, UEA-I and Con A showed different stainings for the nasal glands. UEA-I showed intense staining in the BSE and in the nasal glands located in the ventral wall of the MNC (VNG), whereas Con A showed intense staining in the BSE and in the nasal glands located in the dorsal and medial wall of the MNC (DMNG). The DMNG were observed to send their excretory ducts into the OE, whereas no excretory ducts were observed from the VNG to the OE or the VNE. These results suggested that the secretion by the supporting cells as well as the BSE and the DMNG establishes that there are heterogeneous mucous environments in the OE and the VNE, although both epithelia are situated in the same nasal cavity.     

Regulation of Th2 cell differentiation by mel-18, a mammalian polycomb group gene

Polycomb group (PcG) gene products regulate homeobox gene expression in Drosophila and vertebrates and also cell cycle progression of immature lymphocytes. In a gene-disrupted mouse for polycomb group gene mel-18, mature peripheral T cells exhibited normal anti-TCR-induced proliferation; however, the production of Th2 cytokines (IL-4, IL-5, and IL-13) was significantly reduced, whereas production of IFNgamma was modestly enhanced. Th2 cell differentiation was impaired, and the defect was associated with decreased levels in demethylation of the IL-4 gene. Significantly, reduced GATA3 induction was demonstrated. In vivo antigen-induced IgG1 production and Nippostrongylus brasiliensis-induced eosinophilia were significantly affected, reflecting the deficit in Th2 cell differentiation. Thus, the PcG gene products play a critical role in the control of Th2 cell differentiation and Th2-dependent immune responses.     

Mechanisms of in vivo generation of cytotoxic activity against syngeneic tumours. I. Local differentiation of mature cytotoxic T lymphocytes in the rejection of tumours.

Mature cytotoxic T lymphocytes (CTL) were detected in the peritoneal cavity of syngeneic mice immunized intraperitoneally (i.p.) with mitomycin C (MC)-treated EL-4 or X5563 cells, but were not found in their spleens or lymph nodes. Mature CTL appeared among PE cells after transfer of spleen cells from those immune mice, along with MC-treated tumour cells, to the peritoneal cavity of syngeneic mice. These results lead us to the hypothesis that immature CTL primed in the spleen and lymph nodes may migrate to the site of tumour inoculation and differentiate into mature CTL after antigenic or non-specific stimulation at that site. Inability of primed CTL to differentiate to mature CTL in the spleen might be explained by the effect of splenic suppressor cells, since mature CTL became detectable in the spleen of immune mice by treatment with cyclophosphamide.     

CD69-null mice protected from arthritis induced with anti-type II collagen antibodies

CD69, known as an early activation marker antigen on T and B cells, is also expressed on platelets and activated neutrophils, suggesting certain roles in inflammatory diseases. In order to address the role of CD69 in the pathogenesis of arthritis, we established CD69-null mice. CD69-null mice displayed a markedly attenuated arthritic inflammatory response when injected with anti-type II collagen antibodies. Cell transfer experiments with neutrophils, but not T cells or spleen cells, from wild-type mice into CD69-null mice restored the induction of arthritis. These results indicate a critical role for CD69 in neutrophil function in arthritis induction during the effector phase. Thus, CD69 would be a possible therapeutic target for arthritis in human patients.     

Inhibition of chlamydia trachomatis growth by human interferon-alpha: mechanisms and synergistic effect with interferon-gamma and tumor necrosis factor-alpha

We have evaluated the effect of natural human interferon (IFN)-alpha on the growth of chlamydia trachomatis in human epithelial cells in vitro and revealed that IFN-alpha has reduced both growth and infectivity of C. trachomatis. The effect of IFN-alpha was reversed by the addition of exogenous L-tryptophan and iron to the culture medium, suggesting that antichlamydial effect of IFN-alpha was caused by depletion of intracellular tryptophan and iron, both of which are essential for chlamydial growth. When IFN-alpha was combined with another antichlamydial cytokines, IFN-gamma and tumor necrosis factor (TNF)-alpha, the effect was synergistically enhanced. Therefore, IFN-alpha would act coordinately with other cytokines such as IFN-gamma and TNF-alpha, and play an important role in host defense against infection and in the establishment of persistent chlamydial infection of host, in which the organism remains viable, but in a culture-negative state.     

Abnormal accumulation in lipopolysaccharide in biliary epithelial cells of rats with self-filling blind loop

Primary sclerosing cholangitis (PSC) is known to be frequently associated with inflammatory bowel diseases. In a rat with self-filling blind loop (SFBL), a proposed animal model for PSC, hepatobiliary inflammation has previously been demonstrated. In this study, we assessed the involvement of lipopolysaccharide (LPS), a bacterial endotoxin, in the pathogenesis of hepatobiliary inflammation of the SFBL model. The hepatic localization of LPS was examined by immunohistochemistry using an anti-lipid A antibody. The portal blood concentration of LPS was measured by an endotoxin-specific chromogenic Limulus test (Endospecy test). LPS was localized in the biliary epithelial cells (BECs) of rats with SFBL, and the portal blood concentration of LPS was significantly higher than that of sham-operated rats. Development of hepatobiliary inflammation, peribiliary fibrosis, and injury to the intestinal mucosa were histologically confirmed. Constriction in the biliary trees was radiologically demonstrated. These findings suggested that abnormal accumulation of LPS, which may be derived from portal blood, in BECs was involved in the pathogenesis of hepatobiliary inflammation with intestinal injury.     

The effectors of killer activity induced by interferon-alpha and gamma in peripheral blood mononuclear cells

The nature of effectors of interferon (IFN)-alpha or IFN-gamma-induced killer cell activity remains unclear. The aim of this study was to examine killer cell activity induced by IFN-alpha alone, IFN-gamma alone or a combination of both in patients with renal cell carcinoma (RCC) and to determine the phenotypic patterns of these effectors. The study group included 14 patients (12 men and 2 women, median age 64 years, range 36-77) with confirmed RCC. Peripheral blood mononuclear cells (PBMC) from RCC patients or normal volunteers were cultured with IFN-alpha alone, IFN-gamma alone or a combination of both. Cytotoxic activity was assayed against ACHN cells. Subpopulations of effector cells in IFN-induced killer cell activity were characterized by cell sorting. The most effective type of IFN and the optimal concentration of IFN necessary to induce the maximal killer cell activity varied among RCC patients. The killer activity induced by a combination of IFN-alpha and IFN-gamma was significantly greater than that induced by IFN-alpha or IFN-gamma alone. The greatly increased killer activity induced by IFN-alpha and IFN-gamma was seen in the subpopulations CD3(-) CD16(+), CD3(-) CD56(+) and subpopulation CD3(+)CD4(-), CD3(-)CD16(+), CD3(-)CD56(+), CD57(+)CD16(-), respectively. An optimal type of IFN and optimal concentration of IFN seem to increase the effective rate of treatment of RCC. In addition, the role of IFN-alpha seems to be different from that of IFN-gamma in host defense against RCC. A combination treatment with IFN-alpha and IFN-gamma seems to be suitable to increase the effective rate if we could reduce the side effects of IFNs.     

Cytomegalovirus infections following umbilical cord blood transplantation using reduced intensity conditioning regimens for adult patients.

Cytomegalovirus (CMV) infection is a major complication after allogeneic hematopoietic stem cell transplantation (Allo-HSCT); however, we have little information on the clinical features of CMV reactivation after cord blood transplantation using reduced-intensity regimens (RI-CBT) for adults. We reviewed medical records of 140 patients who underwent RI-CBT at Toranomon Hospital between January 2002 and March 2005. All the patients were monitored for CMV-antigenemia weekly, and, if turned positive, received preemptive foscarnet or ganciclovir. Seventy-seven patients developed positive antigenemia at a median onset of day 35 (range, 4-92) after transplant. Median of the maximal number of CMV pp65-positive cells per 50,000 cells was 22 (range, 1-1806). CMV disease developed in 22 patients on a median of day 35 (range, 15-106); 21 had enterocolitis and 1 had adrenalitis. CMV antigenemia had not been detected in 2 patients, when CMV disease was diagnosed. CMV disease was successfully treated using ganciclovir or foscarnet in 14 patients. The other 8 patients died without improvement of CMV disease. In multivariate analysis, grade II-IV acute graft-versus-host disease was a risk factor of CMV disease (relative risk 3.48, 95% confidential interval 1.47-8.23). CMV reactivation and disease develop early after RI-CBT. CMV enterocolitis may be a common complication after RI-CBT.