Recovery from lactacidosis-induced glial cell swelling with the aid of exogenous anion channels

Hypotonic challenge induces transient swelling in glial cells, which is typically followed by a regulatory volume decrease (RVD). In contrast, lactic acidosis (lactacidosis) induces persistent cell swelling in astrocytes without an accompanying RVD. In the present study, we studied the mechanisms by which lactacidosis interferes with normal volume regulation in rat astrocytic glioma C6 cells. Following exposure of C6 cells to a hypotonic challenge, a current was detected that exhibited properties consistent with those of volume-sensitive outwardly rectifying (VSOR) anion channels. When exposed to in vitro conditions designed to simulate lactacidosis, C6 cells failed to respond to hypotonic stress with an RVD, and VSOR anion currents were not activated. When added to C6 cells, an anion channel-forming protein purified from Helicobacter pylori, VacA, was found to form anion-selective channels in the plasma membrane, and the activity of the VacA channel was not affected by lactacidosis (pH 6.2). Cells preincubated with VacA and then exposed to lactacidotic conditions underwent transient swelling followed by RVD. In contrast, application of a cation ionophore, gramicidin, failed to inhibit lactacidosis-induced persistent cell swelling. From these results, we conclude that inhibition of a volume-sensitive anion channel contributes to persistent swelling induced by lactacidosis in glial cells. Introduction of anion channel activity into glial cells might provide a novel approach for treating cerebral edema, which is associated with lactacidosis in cerebral ischemia or head injury.     

DNA-adduct formation in lungs,nasal mucosa,and livers of rats exposed to urban roadside air in Kawasaki City,Japan

The potency of ambient air for DNA-adduct formation was estimated using Wistar rats. The animals were maintained in a small-animal facility located beside a main highway intersection in Kawasaki City, Japan, for up to 60 weeks and were exposed to roadside air contaminated mainly with automobile emission (exposure group, EG) or to clean air (control group, CG). Compared to CG, the relative adduct levels (RAL) were increased significantly in EG lungs (17.1-fold (P<0.05)), nasal mucosa, and livers after exposure for 4 weeks. However, there were no significant differences in RAL between EG and CG after exposure for 12 weeks, but they were elevated again in EG after exposure for 48 or 60 weeks. These results suggest that roadside air in this region can cause the generation of DNA adducts. This activity of ambient roadside air can be estimated using experimental animals, indicating that biological monitoring of DNA-adduct formation may be a powerful tool to assess the effect of ambient air on human health.     

Cisplatin-resistant HeLa Cells Are Resistant to Apoptosis via p53-dependent and -independent Pathways

Since HeLa cells possess very little functional p53 activity, they could be originally resistant to genotoxic stress-induced apoptosis. Therefore, it is likely that the drug-resistant cells derived from HeLa cells are more resistant to apoptosis. The aim of this study was to determine whether cisplatin-resistant cells derived from HeLa cells have an apoptosis-resistant phenotype. A cisplatin-resistant cell subline, HeLa/CDDP cells, showed a 19-fold resistance to cisplatin compared with the parent cells. The subline showed a collateral sensitivity to paclitaxel. An equitoxic dose (IC₅₀) of cisplatin produced DNA fragmentation in HeLa cells but not in HeLa/CDDP cells. Transfection of wild-type p53 gene enhanced the cytotoxicity of cisplatin and cisplatin-induced apoptosis in HeLa cells but not in HeLa/CDDP cells, although it caused p53 overexpression in both cell lines. The expression of caspase 1 (interleukin-1β-converting enzyme, ICE) mRNA and the overexpression of bax protein were observed only in HeLa cells. Paclitaxel-induced DNA fragmentation appeared less in HeLa/CDDP cells than in HeLa cells. p53 gene transfection did not affect the extent of DNA fragmentation in either cell line, suggesting that paclitaxel may induce p53-independent apoptosis. These findings suggest that HeLa/CDDP cells may have an acquired phenotype that is resistant to p53-dependent and -independent apoptosis.     

Thallium-201 SPECT of adjacent intracranial tumours: a contrast in thallium kinetics

We report a case of adjacent intracranial tumours: malignant fibrous histiocytoma (MFH) and meningioma. Thallium-201 single-photon emission computed tomography demonstrated different thallium kinetics between the tumours (slow washout from the MFH and rapid clearance in the meningioma) and could be said to have been useful for preoperative histological estimation. Received: 7 October 1998 Accepted: 8 February 1999     

Susceptibility of human T-cell leukemia virus type I-infected cells to humanized anti-CD30 monoclonal antibodies in vitro and in vivo

Adult T-cell leukemia (ATL) is an aggressive malignancy of activated CD4⁺ T cells associated with human T-cell leukemia virus type I (HTLV-I) infection. No conventional chemotherapy regimen has appeared successful in patients with ATL, thus establishing effective therapy is urgently required. In some cases, ATL tumor cells express CD30 on the cell surface, therefore, a therapy with mAb against CD30 would be beneficial. To investigate the effect of CD30-mediated therapy on ATL, we assessed SGN-30, a chimeric anti-CD30 mAb, and SGN-35, a monomethyl auristatin E-conjugated anti-CD30 mAb, in vitro and in vivo . Three HTLV-I-infected cell lines were co-cultured with SGN-30 or SGN-35, and the growth-inhibitory effects on the HTLV-I-infected cells were evaluated using an in vitro cell proliferation assay and cell cycle analysis. SGN-30 and SGN-35 showed growth-inhibitory activity against the HTLV-I-infected cell lines by apoptosis and/or cell growth arrest in vitro . To further investigate the effects of SGN-30 and SGN-35 on HTLV-I-infected cells in vivo , we used NOD/SCID mice subcutaneously engrafted with HTLV-I-infected cells. Both mAbs significantly inhibited the growth of HTLV-I-infected cell tumors in the NOD/SCID murine xenograft models. These data suggest that CD30-mediated therapy with SGN-30 or SGN-35 would be useful for patients with ATL. ( Cancer Sci 2009)     

Dislodgment of an atrial screw-in pacing lead 10 years after implantation

Dislodgment of an atrial screw-in pacing lead is quite rare. This report describes a rare case of an atrial screw-in lead dislodgment 10 years after implantation. Although it is an uncommon complication, very late dislodgment can occur postoperatively, and careful follow-up is necessary.     

Angiotensin II type 1 antagonist suppress left ventricular hypertrophy and myocardial fibrosis in patient with end stage renal disease (ESRD)

Fibrosis of left ventricle commonly occurs in end stage renal disease(ESRD) patients and is an independent risk factor of cardiovascular events. Angiotensin II type 1 receptor antagonist may be able to reverse fibrosis of left ventricle in ESRD patients. Ultrasonography-integrated backscatter(IBS) of myocardial walls is directly related to the morphometrically evaluated collagen content in humans. In this study, 30 chronically hemodialyzed patients with hypertension were randomly allocated to receive antihypertensive therapy with either angiotensin II type 1 receptor(AT1-R) antagonist losartan(n = 10), angiotensin-converting enzyme(ACE) inhibitor enalapril(n = 10) or calcium antagonist amlodipine(n = 10). IBS of posterior wall of left ventricule were measured by IBS before and after 6 months treatment. Baseline demographic and clinical characteristics did not differ in three subgroups. Although losartan(34.2 +/- 1.8 to 30.2 +/- 2.4 dB: p = 0.0094) treatment demonstrated significant reduce of IBS values, enalapril(30.3 +/- 1.5 to 31.7 +/- 1.4 dB: p = 0.3268) and amlodipine (31.6 +/- 1.6 to 33.1 +/- 1.9 dB: p = 0.4632) did not changed it significantly before and after 6 months treatment. All three groups reduced left ventricular mass index(Losartan 154.5 +/- 9.9 to 114.6 +/- 5.8 g/m2: p = 0.0002) (enalapril 155.6 +/- 14.3 to 135.3 +/- 10.4 g/m2: p = 0.0275) (amlodipine 156.6 +/- 7.3 to 137.2 +/- 4.1 g/m2: p = 0.0589). Three groups manifested a similar significant decrease in the mean blood pressure. Plasma angiotensin II concentration was markedly increased by 5.0-fold relative to the control levels before treatment in Losartan treatment, in contrast unchanged in enalapril and only 2.0-fold increased in amlodipine treatment. This study indicates that losartan reduce of fibrosis of left ventricule and this effect may be via an anti-AT1-R effect.     

Clinical characteristics of Japanese reflux esophagitis patients as determined by Los Angeles classification

BACKGROUND: Recent studies have shown that the number of patients with reflux esophagitis is increasing in Japan, but the prevalence and risk factors associated with reflux esophagitis in Japanese patients are not well defined. METHODS: By using all endoscopic records in the Katta General Hospital from April through to September 1999, we identified 392 patients. We examined the Los Angeles classification, peptic ulcer, gastric mucosal atrophy, hiatal hernia and other medical variable factors for their contribution to esophagitis in the patients. RESULTS: Patients (13.8%) were diagnosed as having reflux esophagitis with a mucosal break. In a multivariate analysis, reflux esophagitis was associated with hiatal hernia (odds ratio (OR) 2.276, 95% confidence interval (CI) 1.164-4.450), with patients over 65 years of age (OR 2.521, 95% CI 1.238-5.134) and the open type of gastric mucosal atrophy (OR 0.420, 95% CI 0.225-0.785). There was no significant difference between esophagitis and Helicobacter pylori infection and peptic ulcer. CONCLUSIONS: We observed that age, hiatal hernia and a lower rate of gastric mucosal atrophy were associated with the proportion of mucosal breaks accompanying esophagitis.