Mice with R2509C-RYR1 mutation exhibit dysfunctional Ca2+ dynamics in primary skeletal myocytes.

Type 1 ryanodine receptor (RYR1) is a Ca2+ release channel in the sarcoplasmic reticulum (SR) of the skeletal muscle and plays a critical role in excitation-contraction coupling. Mutations in RYR1 cause severe muscle diseases, such as malignant hyperthermia, a disorder of Ca2+-induced Ca2+ release (CICR) through RYR1 from the SR. We recently reported that volatile anesthetics induce malignant hyperthermia (MH)-like episodes through enhanced CICR in heterozygous R2509C-RYR1 mice. However, the characterization of Ca2+ dynamics has yet to be investigated in skeletal muscle cells from homozygous mice because these animals die in utero. In the present study, we generated primary cultured skeletal myocytes from R2509C-RYR1 mice. No differences in cellular morphology were detected between wild type (WT) and mutant myocytes. Spontaneous Ca2+ transients and cellular contractions occurred in WT and heterozygous myocytes, but not in homozygous myocytes. Electron microscopic observation revealed that the sarcomere length was shortened to ∼1.7 µm in homozygous myocytes, as compared to ∼2.2 and ∼2.3 µm in WT and heterozygous myocytes, respectively. Consistently, the resting intracellular Ca2+ concentration was higher in homozygous myocytes than in WT or heterozygous myocytes, which may be coupled with a reduced Ca2+ concentration in the SR. Finally, using infrared laser-based microheating, we found that heterozygous myocytes showed larger heat-induced Ca2+ transients than WT myocytes. Our findings suggest that the R2509C mutation in RYR1 causes dysfunctional Ca2+ dynamics in a mutant-gene dose-dependent manner in the skeletal muscles, in turn provoking MH-like episodes and embryonic lethality in heterozygous and homozygous mice, respectively.

Heat-hypersensitive mutants of ryanodine receptor type 1 revealed by microscopic heating.

Thermoregulation is an important aspect of human homeostasis, and high temperatures pose serious stresses for the body. Malignant hyperthermia (MH) is a life-threatening disorder in which body temperature can rise to a lethal level. Here we employ an optically controlled local heat-pulse method to manipulate the temperature in cells with a precision of less than 1 °C and find that the mutants of ryanodine receptor type 1 (RyR1), a key Ca2+ release channel underlying MH, are heat hypersensitive compared with the wild type (WT). We show that the local heat pulses induce an intracellular Ca2+ burst in human embryonic kidney 293 cells overexpressing WT RyR1 and some RyR1 mutants related to MH. Fluorescence Ca2+ imaging using the endoplasmic reticulum-targeted fluorescent probes demonstrates that the Ca2+ burst originates from heat-induced Ca2+ release (HICR) through RyR1-mutant channels because of the channels' heat hypersensitivity. Furthermore, the variation in the heat hypersensitivity of four RyR1 mutants highlights the complexity of MH. HICR likewise occurs in skeletal muscles of MH model mice. We propose that HICR contributes an additional positive feedback to accelerate thermogenesis in patients with MH.

Differentiation between IgG4-related Mikulicz disease and Sjögren's syndrome: A review case report and literature review.

RATIONALE: IgG4-related diseases cause lesions in various organs throughout the body. In otorhinolaryngology, IgG4-related Mikulicz's disease is suspected and diagnosed based on the presence of lesions of the head and neck, salivary and lacrimal gland enlargement, and bilateral sinus opacity concentrated on the maxillary sinuses. However, in some cases, it is necessary to consider about differentiation between IgG4-related Mikulicz's disease and Sjögren syndrome. PATIENT CONCERNS AND DIAGNOSIS: A 75-years-old male patient visited our hospital with bilateral otitis media with effusion, which was resistant to conservative treatment. Other symptoms at presentation included enlarged bilateral submandibular and sublingual glands marked oral dryness, severe decrease in saliva secretion (1 mL/10 minutes), and dry eyes. We conducted a Schirmer's and fluorescent dye tests, both of which were positive. High serum IgG4 levels were observed, and although the Sjögren syndrome (SS)-A/SS-B antibodies were negative, marked hypolacrimation and tear secretion were observed. Therefore, a detailed examination considering both IgG4-related Mikulicz's disease and SS was conducted. Salivary gland scintigraphy performed prior to the salivary gland biopsy revealed a marked decrease in uptake, which satisfied the diagnostic criteria for SS; however, it was difficult to diagnose IgG4-related disease based on the diagnostic definition. INTERVENSIONS: Although a definitive diagnosis of SS was made, the persistent otitis media with effusion that was resistant to conservative treatment and bilateral mixed hearing loss were confirmed. As mixed hearing loss is considered an otological symptom of IgG4-related disease, oral steroid treatment was administered. OUTCOME: Thereafter, marked recovery of hearing and reduced swelling and induration of the bilateral parotid and submandibular glands were observed. Clinically, IgG4-related Mikulicz's disease was strongly suspected, but a definite diagnosis of SS was made. LESSONS: In the absence of an IgG4-related Mikulicz's disease diagnosis, careful differentiation between IgG4-related Mikulicz's disease and 2 diseases and their diagnostic criteria was essential.

A novel RyR1-selective inhibitor prevents and rescues sudden death in mouse models of malignant hyperthermia and heat stroke.

Mutations in the type 1 ryanodine receptor (RyR1), a Ca2+ release channel in skeletal muscle, hyperactivate the channel to cause malignant hyperthermia (MH) and are implicated in severe heat stroke. Dantrolene, the only approved drug for MH, has the disadvantages of having very poor water solubility and long plasma half-life. We show here that an oxolinic acid-derivative RyR1-selective inhibitor, 6,7-(methylenedioxy)-1-octyl-4-quinolone-3-carboxylic acid (Compound 1, Cpd1), effectively prevents and treats MH and heat stroke in several mouse models relevant to MH. Cpd1 reduces resting intracellular Ca2+, inhibits halothane- and isoflurane-induced Ca2+ release, suppresses caffeine-induced contracture in skeletal muscle, reduces sarcolemmal cation influx, and prevents or reverses the fulminant MH crisis induced by isoflurane anesthesia and rescues animals from heat stroke caused by environmental heat stress. Notably, Cpd1 has great advantages of better water solubility and rapid clearance in vivo over dantrolene. Cpd1 has the potential to be a promising candidate for effective treatment of patients carrying RyR1 mutations.

Epidemiological study using IgM and IgG antibody titers against SARS-CoV-2 in The University of Tokyo, Japan (UT-CATS).

INTRODUCTION: The worldwide pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has continued to date. Given that some of the patients with coronavirus disease 2019 (COVID-19) are asymptomatic, antibody tests are useful to determine whether there is a previous infection with SARS-CoV-2. In this study, we measured IgM and IgG antibody titers against SARS-CoV-2 in the serum of asymptomatic healthy subjects in The University of Tokyo, Japan. METHODS: From June 2020, we recruited participants, who were students, staff, and faculty members of The University of Tokyo in the project named The University of Tokyo COVID-19 Antibody Titer Survey (UT-CATS). Following blood sample collection, participants were required to answer an online questionnaire about their social and health information. We measured IgG and IgM titers against SARS-CoV-2 using iFlash-SARS-CoV-2 IgM and IgG detection kit which applies a chemiluminescent immunoassay (CLIA) for the qualitative detection. RESULTS: There were 6609 volunteers in this study. After setting the cutoff value at 10 AU/mL, 32 (0.48%) were positive for IgG and 16 (0.24%) for IgM. Of six participants with a history of COVID-19, five were positive for IgG, whereas all were negative for IgM. The median titer of IgG was 0.40 AU/mL and 0.39 AU/mL for IgM. Both IgG and IgM titers were affected by gender, age, smoking status, and comorbidities. CONCLUSIONS: Positive rates of IgG and IgM titers were relatively low in our university. Serum levels of these antibodies were affected by several factors, which might affect the clinical course of COVID-19.

[Association of self-rated health with inflammatory markers among nursing home employees].

OBJECTIVES: Although self-rated health (SRH), the self-evaluation of one's own health status, has been reported to be associated with the immune status, the relationship between three different SRH measures (global, self-comparative, and age-comparative) with inflammatory markers as well as the relative strength of these associations by age are not well understood. The current study investigated the associations between SRH measures and inflammatory markers among nursing home employees. METHODS: A sample of 120 Japanese employees at a nursing home (90 women and 30 men), aged 21-68 years (mean, 40.9 years), underwent a blood test for the measurement of inflammatory markers (interferon-γ, interleukin [IL]-4, IL-6, and tumor necrosis factor [TNF]-α, white blood cell count) and SRH during the annual health checkup. Multiple regression analysis adjusted for covariates was performed to analyze the relationship between inflammatory markers and SRH measures stratified by age, that is, aged < 40 years (younger age group) and 40 years and over (older age group). RESULTS: Among the participants aged 40 years and over, poor global SRH was significantly associated with an increase in IL-6, while poor age-comparative SRH was significantly associated with an increase in TNF-α among participants aged < 40 years in the fully adjusted model controlling for potential confounders. Age-comparative SRH was also significantly associated with an increase in IL-6 among all participants. Self-comparative SRH was not significantly associated with inflammatory markers. CONCLUSIONS: Our results suggest that three SRH measures are not equivalently associated with inflammatory markers, especially when the analyses were performed separately for the younger and older populations. This implies that not only differences in forms of SRH but also in age modify the relationship between SRH and inflammatory markers.

Roles of Reexamination of Core Beliefs and Rumination in Posttraumatic Growth Among Parents of Children With Cancer: Comparisons With Parents of Children With Chronic Disease.

BACKGROUND: Studies have indicated that the impact of a traumatic experience can be negative and can provide the opportunity to experience psychological growth, known as posttraumatic growth (PTG). OBJECTIVE: To evaluate the role of cognitive processing in PTG among parents of childhood cancer survivors (CCSs) based on the PTG theoretical model. We compared the model between parents of SCC and parents of children with chronic disease (CCDs) to determine how the role of cognitive processing in PTG is different depending on the children's illness. METHODS: Final sample consisted of 78 parents of CCSs and 44 parents of CCDs. The survey included standardized measurements assessing reexamination of core beliefs, intrusive and deliberate rumination, posttraumatic stress symptoms, and PTG. The hypothetical relationships among the variables were tested by covariance structure analysis. RESULTS: Posttraumatic growth among parents of CCSs had significantly strong association with reexamination of core beliefs, but not with deliberate rumination. Reexamination of core beliefs was significantly more likely to foster PTG among parents of CCSs, whereas deliberate rumination was significantly more likely to be associated with PTG among parents of CCDs. CONCLUSIONS: For parents of CCSs, reexamination of core beliefs had a greater impact on PTG than deliberate rumination. Our results suggest that support should focus on the process of reexamining core beliefs in facilitating PTG among parents of CCSs. IMPLICATIONS FOR PRACTICE: Nurses should provide parents of CCSs with reassurance regarding their experiences of the reexamination of core beliefs, which will likely lead to PTG.

Generation of Pax6-IRES-EGFP knock-in mouse via the cloning-free CRISPR/Cas9 system to reliably visualize neurodevelopmental dynamics.

Pax6 encodes a transcription factor that plays pivotal roles in eye development, early brain patterning, neocortical arealization, and so forth. Visualization of Pax6 expression dynamics in these events could offer numerous advantages to neurodevelopmental studies. While CRISPR/Cas9 system has dramatically accelerated one-step generation of knock-out mouse, establishment of gene-cassette knock-in mouse via zygote injection has been considered insufficient due to its low efficiency. Recently, an improved CRISPR/Cas9 system for effective gene-cassette knock-in has been reported, where the native form of guide RNAs (crRNA and tracrRNA) assembled with recombinant Cas9 protein are directly delivered into mouse fertilized eggs. Here we apply this strategy to insert IRES-EGFP-pA cassette into Pax6 locus and achieve efficient targeted insertions of the 1.8 kb reporter gene. In Pax6-IRES-EGFP mouse we have generated, EGFP-positive cells reside in the eyes and cerebellum as endogenous Pax6 expressing cells at postnatal day 2. At the early embryonic stages when the embryos are transparent, EGFP-positive regions can be easily identified without PCR-based genotyping, precisely recapitulating the endogenous Pax6 expression patterns. Remarkably, at E12.5, the graded expression patterns of Pax6 in the developing neocortex now become recognizable in our knock-in mice, serving a sufficiently sensitive and useful tool to precisely visualize neurodevelopmental processes.

Analysis of HTLV-1 proviral load (PVL) and antibody detected with various kinds of tests in Japanese blood donors to understand the relationship between PVL and antibody level and to gain insights toward better antibody testing.

Adult T-cell leukemia/lymphoma (ATL) occurs in approximately 5% of individuals infected with human T-cell leukemia virus type 1 (HTLV-1). A high proviral load (PVL; more than four copies per 100 peripheral blood mononuclear cells (PBMCs) or 1.6 copies per 100 blood leukocytes) and being male are risk factors for ATL development. Whether anti-HTLV-1 antibody level is related to such risk is unknown. Here, PVL and antibody levels were examined using real-time PCR and other tests in 600 HTLV-1 positive screened Japanese blood donors to understand the relationship between PVL and antibody level in asymptomatic carriers and to gain insights toward better antibody testing for HTLV-1 infection. The 430 donors in whom proviral DNA was detected were considered as true positives for HTLV-1 infection. Among donors aged 40 years or older, more males than females had a PVL corresponding to more than 1.6% infected leukocytes, and an antibody titer below the median (P = 0.0018). In antibody tests using an HTLV-1 positive cell line or Env antigens there was a large discrepancy in antibody titer among 13 provirus-positive samples, probably suggesting that antibody-based screening tests should incorporate multiple HTLV-1 antigens, such as Gag and Env antigens.

High ubiquitous mitochondrial creatine kinase expression in hepatocellular carcinoma denotes a poor prognosis with highly malignant potential.

We previously reported the increased serum mitochondrial creatine kinase (MtCK) activity in patients with hepatocellular carcinoma (HCC), mostly due to the increase in ubiquitous MtCK (uMtCK), and high uMtCK mRNA expression in HCC cell lines. We explored the mechanism(s) and the relevance of high uMtCK expression in HCC. In hepatitis C virus core gene transgenic mice, known to lose mitochondrial integrity in liver and subsequently develop HCC, uMtCK mRNA and protein levels were increased in HCC tissues but not in non-tumorous liver tissues. Transient overexpression of ankyrin repeat and suppressor of cytokine signaling box protein 9 (ASB9) reduced uMtCK protein levels in HCC cells, suggesting that increased uMtCK levels in HCC cells may be caused by increased gene expression and decreased protein degradation due to reduced ASB9 expression. The reduction of uMtCK expression by siRNA led to increased cell death, and reduced proliferation, migration and invasion in HCC cell lines. Then, consecutive 105 HCC patients, who underwent radiofrequency ablation with curative intent, were enrolled to analyze their prognosis. The patients with serum MtCK activity >19.4 U/L prior to the treatment had significantly shorter survival time than those with serum MtCK activity ≤ 19.4 U/L, where higher serum MtCK activity was retained as an independent risk for HCC-related death on multivariate analysis. In conclusion, high uMtCK expression in HCC may be caused by hepatocarcinogenesis per se but not by loss of mitochondrial integrity, of which ASB9 could be a negative regulator, and associated with highly malignant potential to suggest a poor prognosis.

Induction of p53-dependent p21 limits proliferative activity of rat hepatocytes in the presence of hepatocyte growth factor.

BACKGROUND: Hepatocyte growth factor (HGF), a potent mitogen for hepatocytes, enhances hepatocyte function without stimulating proliferation, depending on the physiological conditions. p53, a transcription factor, suppresses the cell proliferation by expressing p21(WAF1/CIP1) in various tissues. AIM: To investigate the mechanism through which the hepatocytes maintain mitotically quiescent even in the presence of HGF. METHODS: We studied the relationship between p53 and p21 expression and the effect of p53-p21 axis on hepatocyte proliferation in primary cultured rat hepatocytes stimulated by HGF. Hepatic p21 levels are determined serially after partial hepatectomy or sham operation in rats. RESULTS: DNA synthesis was markedly increased by HGF addition in rat hepatocytes cultured at low density but not at high density. Cellular p53 levels increased in the hepatocytes cultured at both the densities. p21 levels were increased and correlated with cellular p53 levels in hepatocytes cultured at high density but not at low density. When the activity of p53 was suppressed by a chemical inhibitor for p53, cellular p21 levels were reduced, and DNA synthesis was increased. Similarly, p21 antisense oligonucleotide increased the DNA synthesis. In rats after partial hepatectomy, transient elevation of hepatic p21 levels was observed. In contrast, in sham-operated rats, hepatic p21 levels were increased on sustained time scales. CONCLUSION: p53-related induction of p21 may suppress hepatocyte proliferation in the presence of HGF in the setting that mitogenic activity of HGF is not elicitable.

Prediction of hepatocellular carcinoma development by plasma ADAMTS13 in chronic hepatitis B and C.

BACKGROUND: Chronic liver injury evokes a wound healing response, promoting fibrosis and finally hepatocellular carcinoma (HCC), in which hepatic stellate cells play an important role. Although a blood marker of hepatic stellate cells is not known, those cells importantly contribute to the regulation of plasma a disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) activity, a defect of which causes thrombotic thrombocytopenic purpura. METHODS: Plasma ADAMTS13 was evaluated in chronic hepatitis B or C patients with or without HCC. RESULTS: Plasma ADAMTS13 activity significantly correlated with serum aspartate aminotransferase and alanine aminotransferase, liver stiffness value, and aspartate aminotransferase-to-platelet ratio index, irrespective of the presence of HCC, suggesting that it may reflect hepatocellular damage and subsequent wound healing and fibrosis as a result of hepatic stellate cell action. During the three-year follow-up period for patients without HCC, it developed in 10 among 81 patients. Plasma ADAMTS13 activity was significantly higher in patients with HCC development than in those without and was a significant risk for HCC development by univariate and multivariate analyses. Furthermore, during the one-year follow-up period for patients with HCC treated with radiofrequency ablation, HCC recurred in 55 among 107 patients. Plasma ADAMTS13 activity or antigen level was significantly higher in patients with HCC recurrence than in those without and was retained as a significant risk for HCC recurrence by multivariate analysis. CONCLUSIONS: Higher plasma ADAMTS13 activity and antigen level was a risk of HCC development in chronic liver disease. IMPACT: Plasma ADAMTS13 as a potential marker of hepatic stellate cells may be useful in the prediction of hepatocarcinogenesis.

Results of new policies for inpatient rehabilitation coverage in Japan.

BACKGROUND: A new interdisciplinary postacute rehabilitation unit, the Kaifukuki (convalescent) rehabilitation ward (KRW), has been incorporated into the Japanese medical insurance system since 2000. More than 57 000 beds (45 beds per 100 000 population) are currently available nationwide. The maximal coverage for therapy sessions increased from 2 to 3 hours per day, 7 days a week, in 2006. OBJECTIVE: To investigate how changes in policy affected rehabilitation outcomes of KRWs in a retrospective cohort study of 87 917 patients over 10 years. RESULTS: The mean (standard deviation) age of the patients was 73.0 (13.8) years, and 55.4% were women. Diagnoses included stroke (47.9%); orthopedic diseases, including hip fracture (35.2%); and traumatic brain and spinal cord injury (5.4 %). Onset-admission interval (OAI) was 31.5 (18.6) days, length of stay was 75.9 (46.1) days, and 69.1% were discharged home. Daily therapy time was 79.4 (34.5) minutes. Admission/discharge scores of the Barthel Index and the Functional Independence Measure were 49.3 (31.0)/70.4 (31.9) and 75.3 (31.2)/91.7 (31.8), respectively. Year-by-year comparison revealed that older age, greater initial disability, and shorter OAI were coupled with a higher dose of rehabilitative interventions and a higher rate of home discharge. Longitudinal data from a cohort of hospitals implied a small but significant dose-dependent effect of hours of therapy on rehabilitation outcome after stroke. CONCLUSIONS: Although the organization of KRWs is in flux as the system of hospitals grows, results over the past 8 years suggest that changes in national insurance policies are affecting the quantity and organization of rehabilitation interventions and improvement in patient outcomes.

Overexpression of phospholipase Cε in keratinocytes upregulates cytokine expression and causes dermatitis with acanthosis and T-cell infiltration.

Phospholipase Cε (PLCε) is an effector of Ras and Rap small GTPases. We showed previously using PLCε-deficient mice that PLCε plays a critical role in activation of cytokine production in non-immune skin cells in a variety of inflammatory reactions. For further investigation of its role in inflammation, we created transgenic mice overexpressing PLCε in epidermal keratinocytes. The resulting transgenic mice spontaneously developed skin inflammation as characterized by formation of adherent silvery scales, excessive growth of keratinocytes, and aberrant infiltration of immune cells such as T cells and DC. Development of the skin symptoms correlated well with increased expression of factors implicated in human inflammatory skin diseases, such as IL-23, in keratinocytes, and with the accumulation of CD4(+) T cells producing IL-22, a potent inducer of keratinocyte proliferation. Intradermal injection of a blocking antibody against IL-23 as well as treatment with the immunosuppressant FK506 reversed these skin phenotypes, which was accompanied by suppression of the IL-22-producing T-cell infiltration. These results reveal a crucial role of PLCε in the development of skin inflammation and suggest a mechanism in which PLCε induces the production of cytokines including IL-23 from keratinocytes, leading to the activation of IL-22-producing T cells.

Expression of α-taxilin in hepatocellular carcinoma correlates with growth activity and malignant potential of the tumor.

The membrane traffic system has been recognized to be involved in carcinogenesis and tumor progression in several types of tumors. α-taxilin is a newly identified membrane traffic-related molecule, and its up-regulation has been reported in embryonic and malignant tissues of neural origin. In the present study, we analyzed the expression of α-taxilin in relation to clinicopathological features of hepatocellular carcinomas (HCC) and proliferative activity of the tumor determined by proliferating cell nuclear antigen labeling index (PCNA-LI). Twenty-nine surgically resected nodules of HCC (8 well-, 11 moderately-, and 10 poorly-differentiated) were studied. Fifteen cases showed 'strong staining', while 14 cases showed 'weak staining' for α-taxilin. A significantly higher expression of α-taxilin was observed in less-differentiated (p=0.005), and more invasive (p=0.016) HCCs. The 'strong staining' group showed significantly higher PCNA-LI than the 'weak staining' group (the medians of PCNA-LI were 59.4% vs. 14.4%, p<0.0001). We also evaluated the expression of α-taxilin in hepatoma cell lines (PLC/PRF/5, Hep G2 and HuH-6) in association with cell proliferation. The expression levels of α-taxilin protein were correlated with their growth rates. In conclusion, the expression of the α-taxilin protein was related with an increased proliferative activity and a less-differentiated histological grade of HCC. α-taxilin may be involved in cell proliferation of HCC, and its expression can be a marker of malignant potential of HCC.

Involvement of molecular mimicry between human T-cell leukemia virus type 1 gp46 and osteoprotegerin in induction of hypercalcemia.

Human T-cell leukemia virus type-1 (HTLV-1) causes adult T-cell leukemia/lymphoma (ATL), frequently associated with hypercalcemia and bone destruction. A positive correlation between the appearance of an antibody recognizing the central region (Asp197 to Leu216) on Gp46, gp46-197, and the severity of ATL has been demonstrated. In this study, five male Nihon Hakusyoku rabbits were immunized with a synthetic peptide corresponding to the gp46-197 region to clarify its action and mechanism. Two of the rabbits showed piloerection, anorexia, and somnolence, and died soon after booster administration. The serum calcium level of the dead rabbits was significantly high, compared to those of surviving rabbits. Interestingly, amino acid sequences homologous with gp46-197 were found in the carboxyl-terminal half of osteoprotegerin (OPG), an osteoclast inhibitory factor. To confirm the effect of the gp46-197 region on osteogenesis in vivo, the peptide was intraperitoneally administered to male Sprague-Dawley rats. The administration of the gp46-197 peptide resulted in a decrease of bone mineral density (BMD), a significant increase of serum calcium level, and inhibition of normal bone growth in both short- and long-term experiments. In rats, femoral growth inhibition by the gp46-197 peptide was restored by the coadministration of recombinant human OPG. Improvement by OPG in the adverse effect indicates that the central region of HTLV-1 Gp46 acts as an antagonist for OPG and leads to hypercalcemia.

Positive correlation between chymase-like angiotensin II-forming activity in mononuclear cells and serum cholesterol level.

OBJECTIVES: The local renin-angiotensin system is important in cardiovascular diseases. The present study examined the association between angiotensin (Ang) II-forming activity in fractionated peripheral leukocytes and atherosclerotic risks such as blood pressure, smoking, age and serum cholesterol level, and used a new analytical approach for the measurement of chymase-like activity in peripheral blood to assess the relationship between the chymase-like activities in leukocytes and atherosclerotic risks. METHODS: Peripheral blood samples were obtained from normal and high blood pressure patients in the presence or absence of ischemic heart disease. Mononuclear cell or polymorphonuclear cell fraction of leukocyte was isolated by centrifugation with either Lymphoprep or Polymorphprep, respectively. Chymase-like, angiotensin converting enzyme, and cathepsin G-dependent Ang II-forming activities in the homogenates of mononuclear cell or polymorphonuclear cell fraction were measured using Ang I as a substrate. RESULTS: The chymase-like Ang II-forming activity in the mononuclear cell fraction slightly or significantly increased in non-smoker patients with high blood pressure (systolic and diastolic blood pressure, p = 0.11; mean blood pressure, p < 0.05). Chymase-like Ang II-forming activity in the mononuclear cell fraction positively correlated with serum total cholesterol (p < 0.05) level. CONCLUSIONS: Our data indicates that chymase in mononuclear cells from peripheral blood is activated by high blood pressure or hypercholesterolemia.

Ischemic preconditioning in liver pathophysiology.

Brief periods of tissue ischemia produced tissue resistance to prolonged ischemia and reperfusion, a phenomenon called ischemic preconditioning. The mechanisms of ischemic preconditioning were examined in a rat warm ischemia-reperfusion model as well as the effect of ischemic preconditioning on liver regeneration. Ischemic preconditioning decreased liver injury after warm ischemia-reperfusion, which was reversed by Kupffer cell depletion. Ischemic preconditioning stimulated Kupffer cells to produce reactive oxygen species. Scavengers of reactive oxygen species reversed the effect of ischemic preconditioning, and pretreatment with sublethal dose of hydrogen peroxide mimicked ischemic preconditioning effect. Rat livers were preconditioned by ischemia and subjected to 70% partial hepatectomy. Liver regeneration was then evaluated serially. Ischemic preconditioning promoted liver regeneration, which was reversed by adenosine A2 receptor antagonism and mimicked by adenosine A2 receptor agonism. Promotion of liver regeneration by ischemic preconditioning and adenosine A2 receptor agonism were reversed by Kupffer cell depletion. In conclusion, ischemic preconditioning stimulates Kupffer cells to produce reactive oxygen species, leading to hepatocyte protection against warm ischemia-reperfusion injury; and ischemic preconditioning promoted liver regeneration via adenosine A2 receptor pathway in Kupffer cells.

Antibody to the central region of human T-lymphotropic virus type 1 gp46 is associated with the progression of adult T-cell leukemia.

Human T-cell lymphotropic virus type 1 (HTLV-1) is an etiologic agent of adult T-cell leukemia/lymphoma (ATL). HTLV-1 is spread by cell-to-cell transmission via the gp46-197 region, Asp197 to Leu216, on the envelope protein gp46. In the present study, we revealed a positive correlation between the appearance of an antibody recognizing the gp46-197 region (anti-gp46-197 antibody) and the severity of ATL. The prevalence and titer of the anti-gp46-197 antibody were found to be elevated along with the progression of ATL. In serial samples obtained from a single patient, the anti-gp46-197 antibody was detected before treatment in acute phase, then diminished after allogeneic bone marrow transplantation, to which the patient had a complete response. However, the antibody appeared again before a relapse, along with an increase of the serum-soluble interleukin-2 receptor level and proviral load. The results from the other six patients also indicate that seroconversion of this antibody was synchronized with the deterioration of ATL. Taken together, the findings indicate that the anti-gp46-197 antibody may be a novel beacon for gauging the efficacy of therapeutic approaches to ATL, and a survey of this antibody would be useful for identifying asymptomatic carriers infected with HTLV-1 who are at high risk of developing ATL.

Effect of rapamycin on hepatocyte function and proliferation induced by growth factors.

BACKGROUND: Rapamycin is a specific inhibitor of the mammalian target of rapamycin (mTOR). The effect of rapamycin on proliferation and cellular function was studied in hepatocytes stimulated by hepatocyte growth factor (HGF) or transforming growth factor-alpha (TGFalpha). METHODS AND RESULTS: When isolated rat hepatocytes were cultured at low density, the addition of HGF or TGFalpha increased DNA synthesis but did not affect albumin or fibrinogen concentrations in the medium. In contrast, in hepatocytes cultured at high density, the albumin and fibrinogen concentrations, but not DNA synthesis, were increased by HGF or TGFalpha. The HGF- or TGFalpha-induced increase in DNA synthesis and in albumin or fibrinogen concentrations was suppressed by the addition of rapamycin, as well as wortmannin, a phosphatidylinositol-3 kinase inhibitor. CONCLUSION: HGF and TGFalpha stimulate proliferation and function of hepatocytes depending upon the conditions, and rapamycin inhibited these stimulatory effects, possibly by inhibiting the mTOR-dependent signaling pathway.