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Biomedical subjects

S Murakami

Publications and source records attributed to S Murakami.

At least 433 records · Page 24Linked to original sources
PubMed1994

Transactivation of human hepatitis B virus X protein, HBx, operates through a mechanism distinct from protein kinase C and okadaic acid activation pathways.

Human hepatitis B virus (HBV) X protein, HBx, transactivates virus and host genes through a wide variety of cis-elements. Expression of HBx is controlled by HBV enhancer 1 (Enh1). Both Enh1 and the core sequence of Enh1, which consists of an AP-1 related site (cFAP1) and a C stretch, respond to HBx and a phorbol ester (TPA). Biochemical pathways of the responses to HBx and TPA are still controversial. We therefore asked whether HBx and TPA stimulate Enh1 core activity through a common process. Protein kinase C (PKC) inhibitors, H-7 and staurosporin, did not inhibit HBx transactivation at concentrations sufficient to abolish the TPA effects in HepG2 cells. Although HBx transactivation synergized independently with TPA or a phosphoprotein phosphatase inhibitor, okadaic acid (OA), the PKC inhibitors eliminated only the TPA contribution. HBx transactivation required both the cFAP1 and the C stretch of the Enh1 core region; however, mutations in either or both of the two cis-elements demonstrated that TPA augmentation required only cFAP1. These results imply that HBx transactivation operates through a mechanism distinct from the PKC and OA activation pathways.

Base Sequence↗
PubMed1994

Inducible binding of human lymphocytes to hyaluronate via CD44 does not require cytoskeleton association but does require new protein synthesis.

We have examined molecular mechanisms of the PMA-inducible HA binding ability of human lymphocytes. Newly established OS/6 and OS/37, specific for human CD44, specifically inhibited PMA-induced HA binding of several human cell lines, suggesting that both mAb detect HA binding epitope(s) on CD44. Sequential staining revealed that these mAb cross-blocked each other's binding to Molt-4, T lymphoblast lines, and that neither of them interfered with staining of Molt-4 by other anti-CD44 mAb which induced significant homotypic cell aggregation. Biochemical and PCR analyses did not provide any evidence that PMA stimulation induced dramatic changes in molecular weight or molecular isoforms of CD44. Interestingly, HA binding was not affected and rather slightly increased by cytochalasin B which disrupts F-actin microfilament integrity. This suggests that the ability of CD44 to bind to HA does not correlate with the association of CD44 with the cytoskeleton. On the other hand, protein synthesis inhibitors, cycloheximide and anisomycin clearly inhibited the induction of HA binding of PMA-activated Molt-4 without affecting the expression of CD44 at the same time after stimulation. The same treatment had no effect on PMA-induced FN binding of the cells, which was mediated by VLA integrins. These results suggest that the adhesion functions of CD44 and integrins are differently regulated despite the fact that both are induced by PMA stimulation, and that new protein synthesis is essential for the PMA-induced HA binding by CD44.

Anisomycin↗
PubMed1994

Detection of the putative E2 protein of hepatitis C virus in human liver.

The question was asked whether a predicted envelope protein, considered to be processed from the polyprotein precursor encoded by the putative E2/NS1 region of the hepatitis C virus (HCV) genome, may be observed in HCV-infected humans. Two polyclonal antibodies against recombinant E2/NS1 proteins were prepared and their reactivity tested against liver extracts from HCV-infected patients by immunoblotting analysis. A band corresponding to a size of 44 kDa was detected in liver extracts from patients who were positive for the HCV-specific antibody anti-C100-3 but not in liver extracts from patients who did not have anti-C100-3 antibody. Additionally, no band was detected using preimmune sera or antisera which had been preabsorbed with recombinant E2/NS1 proteins. Deglycosylation studies demonstrated that the 44 kDa protein was a glycosylated form of a 38 kDa protein which corresponds to the predicted molecular weight of the putative E2/NS1 protein. These results suggest that the 44 kDa protein is a product of the E2/NS1 region. Frequent observation of the 44 kDa band in cases of chronic active hepatitis C suggests a correlation between the expression of this protein and the progression of hepatitis.

Adult↗
PubMed1994

Highly sensitive detection of viral RNA genomes in blood specimens by an optimized reverse transcription-polymerase chain reaction.

A protocol was developed for a highly sensitive detection of viral RNA in blood specimens by reverse transcription coupled with a nested polymerase chain reaction. Using Japanese encephalitis virus (JEV) as a model, the optimized reverse transcription-polymerase chain reaction (ORTPCR) detects as few as 3-5 virions in 0.1 ml of whole blood specimens. The effectiveness of this assay system is confirmed by diagnosis of human hepatitis C viral (HCV) infection.

Animals↗
PubMed1994

Primary thymic carcinoma: a clinicopathological and immunohistochemical study.

During the treatment of five cases of thymic carcinoma, we conducted a clinicopathological and immunohistochemical study. The patients included four males and one female, whose ages ranged from 50 to 69 years. The histologic breakdown was squamous cell carcinoma in four and small cell carcinoma in one. Immunohistochemically, the squamous cell carcinomas were positive for cytokeratin (intermediate molecular weight) and keratin. However, staining was negative for Leu-7 and chromogranin. A complete resection was achieved in only one case. In all four of the remaining cases, the resection was incomplete due to invasion into adjacent organs and disseminated lesions. Thymic carcinoma is a tumor for which a higher response rate can be expected from multidisciplinary therapy than that for lung cancer. Therefore, it is desirable, from the clinical view, to determine clinical staging and to establish standard operative procedures comprising mediastinal lymph node dissection as well as effective chemotherapy. With respect to pathology, it is hoped that an improved histologic classification will be developed.

Carcinoma, Small Cell↗
PubMed1994

Antigen-specific cell conjugate formation and long-lasting calcium responses in recognition of Mls cellular superantigen by cloned murine T lymphocytes.

T lymphocyte recognition of cell-associated minor lymphocyte stimulation (Mls) superantigen was studied by simultaneous flow cytometric measurement of T cell free ionized intracellular calcium ([Ca2+]i) with the fluorescent probe indo-1 and T cell binding to antigen-presenting cells stained with a long-chained, membrane-fixed cyanine dye. Cloned T cell-B lymphocyte antigen-presenting cell conjugate formation and increased T cell [Ca2+]i were antigen specific and tightly linked in four Mls-reactive T cell clones. The T cell-antigen-presenting cell conjugates were extremely stable and, like T cell [Ca2+]i elevation, were maintained for more than 2 hr. Three ligand-receptor pairs, (i) T cell receptor/antigen+class II, (ii) CD4/class II, and (iii) LFA-1/ICAM-1, were obligatory participants in T cell recognition of cell-bound superantigen since monoclonal antibodies to any of them blocked formation of cell conjugates. Despite previous reports, Mls recognition occurred by the conventional T cell recognition pathway with easily detected phosphoinositide hydrolysis. B cell activation greatly enhances their recognition by Mls-specific T cells.

Animals↗
PubMed1994

Androgen enhances neuronal degeneration in the developing preoptic area: apoptosis in the anteroventral periventricular nucleus (AVPvN-POA).

Perinatal treatment of female rats with androgen decreases the nuclear volume of the anteroventral periventricular nucleus of the preoptic area (AVPvN-POA). In order to examine the effect of androgen on neurogenesis, bromodeoxyuridine (BrdU) was given once on Day 15 of gestation (= E15) to pregnant rats that also received testosterone propionate (TP) injections. When examined at E17, the number of BrdU-labeled neurons in the AVPvN-POA was not significantly different among control female, male, and androgenized female fetuses, suggesting that androgen does not interfere with neurogenesis. At E21, a significant reduction of BrdU-labeled AVPvN neurons was observed in males and androgenized females. These findings support the hypothesis that elimination of a population by cell death is enhanced in males and androgenized females. Similar selective elimination of the AVPvN neurons occurred in the female following neonatal TP treatment. In order to investigate the nature of androgen-induced cell death in the AVPvN-POA, specific labeling of nuclear DNA fragmentation was performed by the TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method. The number of TUNEL-positive cells was significantly greater in neonatally androgenized females, compared to that in control females. Since DNA fragmentation is considered the most characteristic feature of apoptosis, and TUNEL method is based on direct, specific labeling of DNA fragmentation in nuclei in situ, the neuronal death in the AVPvN-POA is apoptotic, and perinatal androgen may induce the selective apoptotic cell death in the AVPvN-POA.

Animals↗
PubMed1994

Automated monitoring of cell concentration and viability using an image analysis system.

In order to automate measurements of cell concentration and viability in a suspended animal cell culture, we have developed an in situ microscopic image analysis system with an effective cell recognition algorithm. With a small amount of sample, this system can measure the cell density rapidly and aseptically. In addition, it can measure a cell size histogram including cell debris small particle distribution. These small particles have been found to be related to the viability of the mouse-mouse hybridoma STK1 cell line. By using cell debris small particle density as an indicator of cell viability, the developed system provides non-destructive viability monitoring without trypan blue staining.

Animals↗
PubMed1994

A clinical analysis of small-sized lung cancer with advanced disease.

A clinical analysis of small-sized lung cancers with advanced disease was conducted on a total of 58 patients: 34 diagnosed as T1N2, 6 as T1N3, 9 as T1M1, and 9 as T4 due to pleural dissemination. The cumulative 5-year survival rate after surgery for the 34 patients with a T1N2 lesion was 17.4%. Of these 34 patients, 24 underwent a curative operation resulting in a 5-year survival rate of 23.7%, but the remaining 10 patients, who underwent a non-curative operation, had a 5-year survival rate of 0%. Extended lymph node dissection for N3 disease has only been performed in recent years, so it is not yet clear whether it will affect the survival rate or not. T4 disease due to pleural dissemination and T1M1 disease associated with intrapulmonary metastasis encountered at thoracotomy could be expected to have relatively long-term survival with the combined use of systemic immunochemotherapy after surgery. In cases diagnosed as T4 due to pleural dissemination, we have recently employed resection of the primary lesion with parietal pleurectomy as the standard operative procedure. For cases of T1M1 with intrapulmonary metastasis confined to the same lobe as the primary lesion, a lobectomy is usually performed, while for cases with intrapulmonary metastasis extending to another lobe, a lobectomy with enucleation of metastatic nodules or pneumonectomy is most often performed instead of an exploratory thoracotomy.

Adult↗
PubMed1994

Malignant fibrous histiocytoma originating in the mediastinum: report of a case.

Malignant fibrous histiocytoma (MFH) is a tumor which most often develops in the soft tissues of the extremities and retroperitoneum, but very rarely originates in the mediastinum. We report herein the case of a 63-year-old man who underwent surgical resection of a rapidly growing tumor in the right thoracic cavity which was diagnosed as an MFH of mediastinal origin on the basis of histological findings, the definitive diagnosis ultimately being made by specific immunostaining.

Histiocytoma, Benign Fibrous↗
PubMed1994

Radiologic appraisal of healing after iliac crest bone grafts.

Radiographic changes were observed in 45 patients who had undergone iliac bone grafting with either metal or wire fixation after resection of the mandible. Changes were generally not observed during the first month after surgery. Bony resorption was seen during the second or third month. Osteogenesis commenced at any stage, but was usually radiographically evident by 3 to 6 months. Union was not radiographically evident in most cases until more than 6 months had elapsed after surgery. For follow up, plain film radiographs 4 to 6 months after surgery are recommended in patients who receive bone grafts.

Adolescent↗
PubMed1994

Direct evidence for the migration of LHRH neurons from the nasal region to the forebrain in the chick embryo: a carbocyanine dye analysis.

To examine the possible migration of luteinizing hormone-releasing hormone (LHRH) neurons from the olfactory placode to the brain, the epithelial cells of the olfactory placode of the chick embryos were labeled with a fluorescent carbocyanine dye DiI at embryonic days 3.5-4.0. The embryos treated with DiI were incubated in ovo for 1 to 7 days. The DiI-labeled cells were first detected in the olfactory epithelium and olfactory nerve one day after the application of DiI. Two to four days after the application of the dye, the labeled cells sequentially appeared in the rostral and medial forebrain, and in the septo-preoptic area. The distribution pattern of DiI-labeled cells closely resembled that of LHRH neurons. Double staining for DiI and LHRH demonstrated that DiI-labeled cells co-expressed LHRH. However, there were a number of DiI-labeled cells which did not co-express LHRH. These results provide evidence for the actual migration of LHRH neurons from the olfactory placode to the septo-preoptic area during the development, and also suggest that some non-LHRH neurons in the forebrain are of olfactory placodal origin.

Animals↗
PubMed1994

Renal and hormonal responses to repeated treatment with enalapril in non-azotemic cirrhosis with ascites.

Since a single dose of the angiotensin-converting enzyme inhibitor enalapril was shown to cause natriuresis in cirrhosis in a previous study, we investigated whether repeated doses of this substance would sustain a favorable renal effect in cirrhosis. Ten milligrams of enalapril maleate were administered once a day for 8 days to ten patients with non-azotemic cirrhosis and ascites. Enalapril reduced blood pressure significantly at 4 to 12 h (systolic blood pressure) and 2, 6, and 8 h (diastolic blood pressure) on day 2, compared to pretreatment (day 0) values, but this depressor effect decreased on day 8. No change in heart rate could be detected. Enalapril significantly suppressed serum angiotensin-converting enzyme activity and plasma aldosterone concentration (p < 0.001 to 0.01), which were elevated prior to treatment, with pretreatment values of 25.8 +/- 1.8 IU/l for serum angiotensin-converting enzyme activity and 241 +/- 67 pg/ml for plasma aldosterone concentration. This drug caused a 12 to 24% increase (p < 0.05 to 0.01) in mean daily urinary volume and a 40 to 54% increase (p < 0.001 to 0.01) in mean daily urinary sodium excretion from the respective pretreatment baselines during the 8-day period. Creatinine clearance was improved (p < 0.05) by the treatment, with mean improvement values from 24 to 34% above the pretreatment value of 47.4 +/- 4.3 ml/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

An experimental study of tracheal reconstruction using a freed piece of the right bronchus.

An experimental study of tracheal reconstruction using a separate piece of bronchus was performed in 6 dogs. After right upper lobectomy, a five-cartilage-ring length of the trachea extending from five cartilage rings above the carina was circumferentially resected; the right bronchus was transected just below the carina and above the second carina to provide the piece of bronchus, which was then interposed between the distal end of the upper trachea and the proximal end of the lower trachea by end-to-end anastomoses. One-stoma type carinal reconstruction (an anastomosis between the carina and the right intermediate bronchus) was performed. After completion of the airway reconstruction, the anastomotic site was wrapped with an omental flap. One dog died 14 days after operation due to anorexia and weakness, the necropsy in this dog revealed severe ischemic change of the interposed bronchus and ulcer formation at the stump of the upper bronchus. The other 5 dogs survived the operation. Bronchoscopically, the findings for the interposed free bronchus revealed severe ischemic change immediately after the operation, but almost normal findings were observed four to five weeks after the operation. The clinical relevance of this method of tracheal reconstruction is discussed.

Anastomosis, Surgical↗