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Biomedical subjects

M Sata

Publications and source records attributed to M Sata.

At least 127 records · Page 7Linked to original sources
PubMed1999

Progressive bronchial obstruction associated with toxic epidermal necrolysis.

Toxic epidermal necrolysis (TEN) is an acute life-threatening condition, characterized by erosion of the mucous membranes, extensive detachment of the epidermis, and severe constitutional symptoms. Pulmonary complications of TEN are reported as rare, but are one of the most common causes of death. Our report focuses on an unusual case of toxic epidermal necrolysis which showed multiple bronchial obliteration during the chronic phase of the disease. Biopsied tissue of the obliterated bronchi demonstrated non-specific granulation. To improve the obliterated ventilatory function, we tried to reopen the bronchial obliteration using a balloon catheter under the guidance of fibreoptic bronchoscopy, however rapid restenosis of the bronchi ensued.

Adult↗
PubMed1999

Detection of hepatitis-C virus and hepatitis-C virus replication in hepatocellular carcinoma by in situ hybridization.

BACKGROUND: Although hepatitis C virus (HCV) is a major causative agent of hepatocellular carcinoma (HCC), the role of this virus in carcinogenesis is not fully understood. METHODS: We studied HCV infection and replication by detecting plus- and minus-strand HCV RNA by in situ hybridization (ISH) in surgically resected HCCs and adjacent non-cancerous tissue obtained from 15 anti-HCV antibody-positive patients with HCC. RESULTS: Plus-strand HCV RNA was found in 9 of 15 HCCs. Both plus- and minus-strand HCV RNA were detected in four of these nine patients. In non-cancerous tissues obtained adjacent to the HCC, plus-strand HCV RNA was found in 10 of 15 patients, whereas both plus- and minus-strand HCV RNA were detected in 7 of these 10 patients. The degree of staining by ISH did not correlate with the differentiation of the HCC, histologic classification of the non-cancerous tissue, serum HCV RNA levels, or serum transaminase levels. CONCLUSIONS: HCV can be found in and replicates in both hepatoma cells and in non-cancerous hepatocytes in anti-HCV antibody-positive patients with HCC. The direct effects of HCV viral gene products on normal hepatocytes in the development of HCC require additional study.

Aged↗
PubMed1999

Mutations in the NS5A gene predict response to interferon therapy in Japanese patients with chronic hepatitis C and cirrhosis.

The virus genotype, serum HCV-RNA level and liver histology are reported to be important factors in the response to interferon therapy. Recent studies have revealed that HCV NS5A 2209-2248 amino acid changes affect the response to interferon therapy of genotype 1b chronic hepatitis C. In contrast, some studies done in western countries have reported no such correlation. In the present study, interferon therapy was given to 58 Japanese patients, including 15 liver cirrhosis patients. NS5A 2209-2248 changes, the serum HCV level, ALT level, age and histology were examined in relation to the interferon effect. Twenty-four of the 58 patients (41%) showed a sustained virological response to the therapy. The responses to interferon therapy were significantly correlated with NS5A 2209-2248 changes (p < 0.0001), the HCV-RNA level (p < 0.0001) and histology (p < 0.0060). Among 15 liver cirrhosis patients, 3 of 6 mutant type patients showed a sustained virological response; 5 intermediate and 4 with wild type virus infected patients showed no responses. In conclusion, NS5A 2209-2248 changes may be a useful predictive marker of response to interferon therapy in addition to the serum HCV RNA level even in histologically advanced patients.

Adult↗
PubMed1999

Helicobacter pylori in the natural environment.

The presence of Helicobacter pylori (H. pylori) in the natural environment has been demonstrated in a number of studies. However, its route of infection into humans is unknown. To study this further, we attempted to detect H. pylori in the natural environment in a region of Japan with a high infection rate. Tap and well water and field soil samples were collected from around the residences of subjects who had participated in an epidemiological survey in 1996. Samples of water from rivers and ponds, and specimens of flies and cow faeces were collected in the region. DNA was extracted from the water, field soil and faecal samples after selective collection of H. pylori by the immunomagnetic-bead separation technique. H. pylori-specific DNA was detected in water, field soil, flies and cow faeces by nested polymerase chain reaction (PCR), and the ureA partial sequences of the PCR products were aligned. The nucleotide sequences of the samples amplified by PCR were highly homologous (96-100%) with the H. pylori sequence in the GenBank database and the H. pylori-specific DNA sequences were highly homologous with each other. These findings suggest the existence of H. pylori in the natural environment and a possible transmission route.

Animals↗
PubMed1999

Intraspousal transmission of GB virus C/hepatitis G virus in an hepatitis C virus hyperendemic area in Japan.

OBJECTIVE: An immunoassay for antibodies against an hepatitis G virus (HGV) protein (anti-E2) was recently developed that might serve as a useful marker for diagnosing recovery from HGV infection. METHODS: We investigated the intraspousal transmission of GB virus C/hepatitis G virus (GBV-C/HGV) using both reverse transcription hemipolymerase chain reaction (RT-hemi-PCR for the 5' untranslated region) and a recently developed anti-E2. RESULTS: Thirty-two GBV-C/HGV-infected index subjects were selected from an hepatitis C virus hyperendemic area in Japan. Of the 32 subjects, seven (6.4%) were GBV-C/HGV RNA-positive, 24 (21.8%) were anti-E2-positive, and one (0.9%) was both GBV-C/HGV RNA- and anti-E2-positive. Among the 32 spouses of these subjects, GBV-C/HGV RNA, anti-E2, and both GBV-C/HGV RNA and anti-E2 positivity were detected in 0, 6, (18.8%), and one (3.1%) spouses, respectively (the total prevalence of GBV-C/HGV was 7 spouses [21.9%]). Thus, the intraspousal transmission of GBV-C/HGV was undeniable in these seven couples. The respective positive rates of 175 sex- and age-matched controls were 7 (4.0%), 26 (14.9%), and 0 (the total prevalence of GBV-C/HGV was 34 [19.4%]). No significant difference in positive rates was observed between the subjects/spouses and the controls. Five spouses among the seven couples who were positive for any of GBV-C/HGV markers had parenteral risk factors such as blood transfusion, acupuncture, and major surgery. CONCLUSION: Based on these observations, we cannot draw a definitive conclusion that intraspousal transmission of GBV-C/HGV had occurred among these seven couples.

Aged↗
PubMed1999

[Two cases of suspected Bartonella henselae infection from a dog].

A 55-year-old male was admitted to our hospital because of fever and left submaxillary, right axillary, and left inguinal lymphadenopathy. A presumptive diagnosis of rickettsiosis was made and treatment with oral doxycycline was started. Lymphadenopathy was partialy resolved after antibiotics treatment. Ablation of the left inguinal node was done and histopathological examination showed non-Hodgkin's lymphoma. Lymphadenopathy was resolved by chemotherapy. The second patient, a 40-year-old male, developed a tender submandibular node. Excisional biopsy of the node was performed to eliminate lymphoma. Histopathological examination revealed granulomatous lymphadenitis with follicular hyperplasia. The patients had no history of cat contact, but owned a dog. Diagnosis of both cases was confirmed by the detection of IgG antibodies to Bartonella henselae with an enzyme immunoassay. Our findings suggest that dogs are implicated in B. henselae infection and can serve as a reservoir of the organism as well as cats. In the abscence of other bacterial and especially after exposure to dogs, B. henselae should be included as possible cause of lymphadenopathy.

Adult↗
PubMed1999

Pulse intravenous cyclophosphamide treatment for steroid-resistant interstitial pneumonitis associated with polymyositis.

Interstitial pneumonitis (IP) is a serious complication in polymyositis/dermatomyositis (PM/DM), leading to significant morbidity or mortality. Here, we report the successful treatment by pulse intravenous administration of cyclophosphamide in the early course of lung involvement in PM, and with subsequent low-dosage oral administration of azathioprine in a patient with steroid-resistant IP associated with PM/DM. Although the precise pharmacological mechanism induced by cyclophosphamide in this disease remains unclear, such a cytotoxic drug raises the possibility of control of steroid-resistant PM/DM-associated IP when used in the early course of IP.

Adult↗
PubMed1999

OK-432 treatment increases matrix metalloproteinase-9 production and improves dimethylnitrosamine-induced liver cirrhosis in rats.

Kupffer cells are major matrix metalloproteinase-producing cells in the liver. The production of metalloproteinases in Kupffer cells may contribute to the improvement of liver fibrosis inducing liver cirrhosis. In this study, we examined the effect of the OK-432 (a biological response modifier) on the dimethylnitrosamine-induced liver cirrhosis in rats. Dimethylnitrosamine (10 microg/ml) was injected intraperitoneally into 20 male Wistar rats 3x/week for 4 weeks. For the subsequent 4 weeks, the animals were injected with saline (1 ml, 1x/week) (Group I, n=10) or OK-432 (1 Klinishe Einheit, 1x/week) (Group II, n=10). The control rats were injected with 1 ml saline for the initial 4 weeks and subsequent 4 weeks (Group III, n=10). The degree of hepatic fibrosis, the immunolocalization of type IV collagen, hyaluronic acid, and alpha-smooth muscle actin, and the mRNA expression by Northern blotting and the activity by gelatin zymography of metalloproteinase-9 were evaluated. Serum aminotransferase, hyaluronic acid, interleukin-1beta and tumor necrosis factor-alpha levels were measured. The deposition of á-smooth muscle actin and extracellular matrix containing type IV collagen and hyaluronic acid was markedly suppressed by OK-432. The mRNA expression and the activity of metalloproteinase-9 were markedly increased by OK-432. The serum aminotransferase and hyaluronic acid levels were decreased by OK-432. The serum interleukin-1 and tumor necrosis factor-alpha values were lower than the detectable limit in all samples from all three groups. These results indicate that OK-432 increased the production of metalloproteinase-9 and improved the rat dimethylnitrosamine-induced liver cirrhosis. OK-432 is suggested to be useful for the treatment of liver cirrhosis.

Actins↗
PubMed1999

Various extrahepatic manifestations caused by hepatitis C virus infection.

It has been reported that hepatitis C virus (HCV) causes not only liver disease but also disorders of other organs and tissues. Previously, many HCV-related extrahepatic manifestations have been reported. In this study, we report 2 patients in whom tongue cancer was detected during the treatment of HCV-related liver disease. In one patient, tongue cancer was detected during the treatment of HCV-related liver cirrhosis, and articular rheumatism developed thereafter. The duration of HCV-related liver disease was 10 years. In the other patient, tongue cancer was detected during the treatment of HCV-related hepatocellular carcinoma. This patient had a past history of thyroid disease. The duration of HCV-related liver disease was 6 years. In these patients, the possibility that several conditions incidentally and concurrently developed cannot be denied. However, the conditions described above may be regarded as HCV-related extra-hepatic manifestations. In patients with HCV infection, it is important to examine conditions in organs other than the liver. Careful follow-up is needed.

Aged↗
PubMed1999

Prognostic benefit in cytoreductive surgery for curatively unresectable hepatocellular carcinoma - comparison to transcatheter arterial chemoembolization.

As a strategy for treating advanced hepatocellular carcinoma (HCC), cytoreductive surgery was studied comparing to transcatheter arterial chemoembolization (TACE). Patients who had curatively unresectable intrahepatic multiple HCC with the main tumor 30 mm or more in size were selected for this study. The patients were classified into two groups; i) cytoreductive surgery group (CRS group): 28 patients in whom the main tumor was resected but other cancer nodules remained in the remnant liver, ii) TACE group: 25 patients at Child A grade who underwent TACE, and in whom it was also evaluated retrospectively that the main tumor had been resectable. The cumulative 5-year survival rate was significantly higher in CRS (48.7%) than TACE (17.1%) group. Multivariate analysis revealed that performing cytoreductive surgery was a significant and independent factor to prolong survival. However, 6 of 28 patients died within one year of surgery. Residual tumor thrombus, and the absence or non-effectiveness of adjuvant therapy were significant high risk factors for postoperative death within one year. Conclusively, cytoreductive surgery contributes to a significant lengthening of survival in patients with advanced HCC. To reduce the risk of early postoperative death, the importance of postoperative adjuvant therapy is also recognized.

Aged↗
PubMed1999

The reticuloendothelial system and macrophage-monocyte system in thorotrast patients.

To evaluate the function of the reticuloendothelial system and macrophage-monocyte system, blood samples from Thorotrast patients and age-matched healthy controls were used to determine the titer of plasma antibodies to lipid A and the numbers of several lymphocyte subclasses in peripheral blood and for an autoradiographic study of peripheral blood monocytes. The titer of plasma IgM class antibodies to lipid A was significantly elevated in the Thorotrast patients. Counts of CD 11-positive lymphocytes and CD 57-positive lymphocytes, which correspond to monocytes and natural killer cells, respectively, were significantly increased in the Thorotrast patients. Autoradiography showed that alpha-particle tracks were emitted from the monocytes isolated from the peripheral blood of Thorotrast patients. Thus the depressed function of the reticuloendothelial system resulted in the activation of the macrophage-monocyte system in the Thorotrast patients.

Aged↗
PubMed1999

The inhibitory effect of recombinant human soluble thrombomodulin on initiation and extension of coagulation--a comparison with other anticoagulants.

Recombinant human soluble thrombomodulin (rhsTM) was compared with various anticoagulants for in vitro anticoagulant effects on thrombin generation, clotting time, and thromboelastography. rhsTM as well as APC reduced the level of the peak of the thrombin generation curve, but we did not observe any time-delay to reach the peak. This effect of rhsTM was diminished in PC-deficient plasma and was closely associated with the inhibitory effect on prothrombinase and factor Va. On the other hand, hirudin and argatroban delayed the time to reach the level of the peak, without reducing it. rhsTM and other anticoagulants except for activated protein C (APC) were found to have concentration-dependent anticoagulant activity by conventional clotting tests. However, the concentration of rhsTM for clotting time was slightly affected by anti-protein C antibody. Moreover, the concentration of rhsTM required to inhibit thrombin activity directly was 50 times higher than that needed to inhibit thrombin generation. The effect of rhsTM on clot development was compared with that of other anticoagulants by thromboelastography; rhsTM reduced the growth of the clot but had little effect on the time to activate clotting, while the other anticoagulants had the opposite effect. This effect of rhsTM was completely abolished by the addition of anti-protein C or anti-protein S antibody. These findings suggest that rhsTM attenuates blood clotting by reducing the level of generated thrombin through protein C activation and subsequent factor Va inactivation and prothrombinase inhibition.

Anticoagulants↗
PubMed1998

Endothelial cell apoptosis induced by oxidized LDL is associated with the down-regulation of the cellular caspase inhibitor FLIP.

Fas (CD-95/APO-1) is a death receptor that initiates an apoptotic signal when activated by its ligand, FasL. Normal vascular endothelial cells are resistant to Fas-mediated apoptosis though they express both Fas and FasL. Oxidized low density lipoprotein (OxLDL) or lysophosphatidylcholine (LPC), a major component of OxLDL, induces endothelial cell suicide by sensitizing endothelial cells to Fas-mediated apoptosis. Here, we show that endothelial cell apoptosis by OxLDL and LPC-C16:0 was dose-dependent and correlated with down-regulation of FLICE-inhibitory protein (FLIP), an intracellular caspase inhibitor. FLIP down-regulation also occurred when endothelial cells were treated with toxic doses of LPC-C18:0 or minimally modified low density lipoprotein (LDL). In contrast, FLIP was not down-regulated by native LDL, acetylated LDL, LPC-C12:0, cholesterol, or 7-ketocholesterol, which are not toxic to endothelial cells. The cytotoxicity of oxidized lipids was reversed by transfecting endothelial cells with a FLIP expression plasmid. The results demonstrate, for the first time, FLIP regulation under conditions that lead to pathological tissue destruction.

Amino Acid Sequence↗
PubMed1998

Oxidized LDL activates fas-mediated endothelial cell apoptosis.

Oxidized low density lipoproteins (OxLDL) promote chronic inflammatory responses in the vasculature that give rise to atherosclerotic plaques. Fas ligand (FasL) is naturally expressed on the vascular endothelium where it can induce apoptosis in Fas-expressing immune cells as they enter the vessel wall. Although vascular endothelial cells are normally resistant to Fas-mediated cell death, OxLDL were shown to induce apoptosis in cultured endothelial cells and endothelium of arterial explants by a process that could be inhibited with Fas L neutralizing antibodies. OxLDL-induced cell death was also reduced in the aortic endothelium cultured from gld (FasL-/-) and lpr (Fas-/-) mice as compared with wild-type mice. OxLDL acted by sensitizing endothelial cells to death signals from the Fas receptor. Thus, the ability of OxLDL to promote Fas-mediated endothelial cell suicide may be a feature that contributes to their atherogenicity.

Animals↗
PubMed1998

A hinge at the central helix of the regulatory light chain of myosin is critical for phosphorylation-dependent regulation of smooth muscle myosin motor activity.

The motor function of smooth muscle myosin is activated by phosphorylation of the regulatory light chain (RLC) at Ser19. However, the molecular mechanism by which the phosphorylation activates the motor function is not yet understood. In the present study, we focused our attention on the role of the central helix of RLC for regulation. The flexible region at the middle of the central helix (Gly95-Pro98) was substituted or deleted to various extents, and the effects of the deletion or substitution on the regulation of the motor activity of myosin were examined. Deletion of Gly95-Asp97, Gly95-Thr96, or Thr96-Asp97 decreased the actin-translocating activity of myosin a little, but the phosphorylation-dependent regulation of the motor activity was not disrupted. In contrast, the deletion of Gly95-Pro98 of RLC completely abolished the actin translocating activity of phosphorylated myosin. However, the unregulated myosin long subfragment 1 containing this RLC mutant showed motor activity the same as that containing the wild type RLC. Since long subfragment 1 motor activity is unregulated by phosphorylation, i.e. constitutively active, these results suggest that the deletion of these residues at the central helix of RLC disrupts the phosphorylation-mediated activation mechanism but not the motor function of myosin itself. On the other hand, the elimination of Pro98 or substitution of Gly95-Pro98 by Ala resulted in the activation of actin translocating activity of dephosphorylated myosin, whereas it did not affect the motor activity of phosphorylated myosin. Together, these results clearly indicate the importance of the hinge at the central helix of RLC on the phosphorylation-mediated regulation of smooth muscle myosin.

Actins↗
PubMed1998

Bax-mediated cell death by the Gax homeoprotein requires mitogen activation but is independent of cell cycle activity.

Tissues with the highest rates of proliferation typically exhibit the highest frequencies of apoptosis, but the mechanisms that coordinate these processes are largely unknown. The homeodomain protein Gax is down-regulated when quiescent cells are stimulated to proliferate, and constitutive Gax expression inhibits cell proliferation in a p21(WAF/CIP)-dependent manner. To understand how mitogen-induced proliferation influences the apoptotic process, we investigated the effects of deregulated Gax expression on cell viability. Forced Gax expression induced apoptosis in mitogen-activated cultures, but quiescent cultures were resistant to cell death. Though mitogen activation was required for apoptosis, neither the cdk inhibitor p21(WAF/CIP) nor the tumor suppressor p53 was required for Gax-induced cell death. Arrest in G1 or S phases of the cell cycle with chemical inhibitors also did not affect apoptosis, further suggesting that Gax-mediated cell death is independent of cell cycle activity. Forced Gax expression led to Bcl-2 down-regulation and Bax up-regulation in mitogen-activated, but not quiescent cultures. Mouse embryonic fibroblasts homozygous null for the Bax gene were refractive to Gax-induced apoptosis, demonstrating the functional significance of this regulation. These data suggest that the homeostatic balance between cell growth and death can be controlled by mitogen-dependent pathways that circumvent the cell cycle to alter Bcl-2 family protein expression.

Animals↗
PubMed1998

Brefeldin A-inhibited guanine nucleotide-exchange activity of Sec7 domain from yeast Sec7 with yeast and mammalian ADP ribosylation factors.

The Saccharomyces cerevisiae Sec7 protein (ySec7p), which is an important component of the yeast secretory pathway, contains a sequence of approximately 200 amino acids referred to as a Sec7 domain. Similar Sec7 domain sequences have been recognized in several guanine nucleotide-exchange proteins (GEPs) for ADP ribosylation factors (ARFs). ARFs are approximately 20-kDa GTPases that regulate intracellular vesicular membrane trafficking and activate phospholipase D. GEPs activate ARFs by catalyzing the replacement of bound GDP with GTP. We, therefore, undertook to determine whether a Sec7 domain itself could catalyze nucleotide exchange on ARF and found that it exhibited brefeldin A (BFA)-inhibitable ARF GEP activity. BFA is known to inhibit ARF GEP activity in Golgi membranes, thereby causing reversible apparent dissolution of the Golgi complex in many cells. The His6-tagged Sec7 domain from ySec7p (rySec7d) synthesized in Escherichia coli enhanced binding of guanosine 5'-[gamma-[35S]thio]triphosphate by recombinant yeast ARF1 (ryARF1) and ryARF2 but not by ryARF3. The effects of rySec7d on ryARF2 were inhibited by BFA in a concentration-dependent manner but not by inactive analogues of BFA (B-17, B-27, and B-36). rySec7d also promoted BFA-sensitive guanosine 5'-[gamma-thio]triphosphate binding by nonmyristoylated recombinant human ARF1 (rhARF1), rhARF5, and rhARF6, although the effect on rhARF6 was very small. These results are consistent with the conclusion that the yeast Sec7 domain itself contains the elements necessary for ARF GEP activity and its inhibition by BFA.

ADP-Ribosylation Factor 1↗