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Biomedical subjects

J Yamaguchi

Publications and source records attributed to J Yamaguchi.

At least 91 records · Page 5Linked to original sources
PubMed1995

[A clinical and pathological study of 46 cases of sudden and unexpected death].

A series of 46 autopsied adult cases of sudden and unexpected natural death were investigated. In this study, sudden and unexpected death was defined as any death occurring with 24 hours of onset of symptoms in a person with or without probable cause of death suggested by medical history. The cases included 31 males and 15 females aged 26 to 85 years (mean 66.6 years). Age distribution peaked in seventies. The lesions causing sudden and unexpected death according to the most frequent organ systems were, diseases of the heart (acute myocardial infarction with or without old infarct, 20; old myocardial infarction without acute infarction, 2; dilated cardiomyopathy, 2; sarcoidosis, 1; amyloidosis, 2; and valvular disease, 2), the aorta (ruptured aneurysm, 6; dissecting aneurysm, 2), the respiratory tract (pulmonary embolism, 7; pulmonary hypertension, 1), the alimentary tract (intestinal obstruction, 1), and other diseases (cause unknown, 1). The cardiovascular lesions were found in 78.2% of cases autopsied. The sudden and unexpected death caused by acute myocardial infarction was found in 47.8%, and acute myocardial infarction seemed to play a major role in cardiac sudden death in these series. The respiratory lesions were found in 17.4%. Four of seven cases with pulmonary embolism died in two weeks after surgical operation. The most common underlying disease was post-operative condition.

Adult↗
PubMed1994

Sequence-specific interactions of a nuclear protein factor with the promoter region of a rice gene for alpha-amylase, RAmy3D.

The expression of a rice gene for alpha-amylase, RAmy3D, in suspension-cultured cells is induced at the transcriptional level by the deprivation of sugars. Binding of a nuclear protein from suspension-cultured rice cells to the promoter region of the RAmy3D gene was studied by gel-retardation and DNase I footprinting assays. Gel-retardation assays indicated that a 358-bp fragment of the promoter region interacted specifically with a protein factor from suspension-cultured cells. DNase I footprinting analysis allowed us to define three protein-binding regions. Each of these protein-binding sequences contained the GCCG G/C CG motif, which is specifically present in the promoter region of the sugar-regulated gene, RAmy3D, for rice alpha-amylase and not in that of the gibberellin-regulated RAmy1A gene. Subsequent cross-competition experiments using gel-retardation assay and synthetic oligonucleotides showed that the GCCG G/C CG motifs directly mediated the binding of a nuclear protein. These observations are discussed in relation to expression of the gene for alpha-amylase in suspension-cultured cells.

Base Sequence↗
PubMed1994

Long-term survival of orthotopic Lewis liver grafts in Wistar Furth rats. Elimination or inactivation of effector CTL and altered antigenicity as possible reasons for tolerance.

After orthotopic transplantation of rat livers from Lewis (LEW) donors into Wistar Furth (WF) recipients, a rejection response occurs 2 weeks after transplantation, followed by indefinite survival of the transplant. Spleen cells from WF rats bearing long-term LEW liver grafts responded in MLR and CML assays like spleen cells from normal WF rats after in vitro stimulation with mitomycin C-treated LEW spleen cells, but did not generate CTL after stimulation with paraformaldehyde-treated LEW spleen cells. Transient damage to the long-term grafted livers was induced by inoculation of recipients with homogenized normal LEW liver. CD8+ CTL were detected in the spleen at the time of this liver damage. These findings indicate that CTL precursors are present in WF rats bearing LEW liver transplants. These CTL precursors are capable of differentiating into effector CTL in vitro and in vivo in response to donor antigen. However, once generated, effector CTL in WF rats are eliminated or become unresponsive to the transplanted LEW liver. Homogenized LEW liver from grafted donors did not induce transient liver damage when inoculated into recipient WF rats bearing LEW liver transplants. The demonstration of large amounts of antibody bound to either parenchymal or nonparenchymal cells in the donor graft suggests that reduction (or loss) of antigenicity could also be responsible for the inability of LEW liver to elicit an immune response in WF-recipient rats. Thus, elimination or inactivation of effector CTL and altered antigenicity could both be responsible for maintaining tolerance after allogeneic liver transplantation.

Animals↗
PubMed1994

A knotted1-like homeobox gene in Arabidopsis is expressed in the vegetative meristem and dramatically alters leaf morphology when overexpressed in transgenic plants.

The homeobox gene knotted1 (kn1) was first isolated by transposon tagging a dominant leaf mutant in maize. Related maize genes, isolated by virtue of sequence conservation within the homeobox, fall into two classes based on sequence similarity and expression patterns. Here, we report the characterization of two genes, KNAT1 and KNAT2 (for knotted-like from Arabidopsis thaliana) that were cloned from Arabidopsis using the kn1 homeobox as a heterologous probe. The homeodomains of KNAT1 and KNAT2 are very similar to the homeodomains of proteins encoded by class 1 maize genes, ranging from 78 to 95% amino acid identity. Overall, the deduced KNAT1 and KNAT2 proteins share amino acid identities of 53 and 40%, respectively, with the KN1 protein. Intron positions are also fairly well conserved among KNAT1, KNAT2, and kn1. Based on in situ hybridization analysis, the expression pattern of KNAT1 during vegetative development is similar to that of class 1 maize genes. In the shoot apex, KNAT1 transcript is localized primarily to the shoot apical meristem; down-regulation of expression occurs as leaf primordia are initiated. In contrast to the expression of class 1 maize genes in floral and inflorescence meristems, the expression of KNAT1 in the shoot meristem decreases during the floral transition and is restricted to the cortex of the inflorescence stem. Transgenic Arabidopsis plants carrying the KNAT1 cDNA and the kn1 cDNA fused to the cauliflower mosaic virus 35S promoter were generated. Misexpression of KNAT1 and kn1 resulted in highly abnormal leaf morphology that included severely lobed leaves. The expression pattern of KNAT1 in the shoot meristem combined with the results of transgenic overexpression experiments supports the hypothesis that class 1 kn1-like genes play a role in morphogenesis.

Amino Acid Sequence↗
PubMed1994

Sequence analysis and expression patterns divide the maize knotted1-like homeobox genes into two classes.

The homeobox of the knotted1 (kn1) gene was used to isolate 12 related sequences in maize. The homeodomains encoded by the kn1-like genes are very similar, ranging from 55 to 89% amino acid identity. Differences outside the precisely conserved third helix allowed us to group the genes into two classes. The homeodomains of the seven class 1 genes share 73 to 89% identical residues with kn1. The four class 2 genes share 55 to 58% identical residues with kn1, although the conservation within the class is greater than 87%. Expression patterns were analyzed by RNA gel blot analysis. Class 1 genes were highly expressed in meristem-enriched tissues, such as the vegetative meristem and ear primordia. Expression was not detectable in leaves. The class 2 genes were expressed in all tissues, although one was abundantly expressed in roots. The genes were mapped using recombinant inbred populations. We determined that clusters of two to three linked genes are present on chromosomes 1 and 8; otherwise, the genes are distributed throughout the genome. Four pairs of genes, similar in both sequence and expression patterns, mapped within duplicated regions of the genome.

Amino Acid Sequence↗
PubMed1994

A function of 40 kDa outer membrane protein in Serratia marcescens.

The function of one of the outer membrane proteins of Serratia marcescens was investigated. S. marcescens with an abundant 40 kDa outer membrane protein was induced to form spheroplast at a high rate in an isotonic medium in the presence of calcium, although the spheroplasts were generally fragile in the isotonic environment. The degree of spheroplast induction was correlated to the amount of the 40 kDa protein present in the membrane. In the 40 kDa proteinless mutant strains, the spheroplast induction rate was remarkably decreased. Autoradiography of the outer membrane revealed the presence of a calcium-binding protein as a radioactive band whose position coincided with the 40 kDa protein. These results suggest that the 40 kDa protein has an important role in maintaining the structural integrity of the cell wall against osmotic shock.

Autoradiography↗
PubMed1994

Relationship between hemolytic activity and adsorption capacity of aluminum hydroxide and calcium phosphate as immunological adjuvants for biologicals.

Aluminum hydroxide (Al) and calcium phosphate (Ca) gels have been used as vaccine adjuvants for many years. We investigated mechanism of the hemolytic activities of both adjuvant materials. The hemolytic activity of each gel depended on the gel dose. The adsorption capacities and the hemolytic activities of both adjuvants decreased as the concentration of phosphate increased in a gel-washing solution. A positive correlation between the hemolytic activity and the adsorption capacity was found in Al-gel. A disruptive effect of Ca-gel on membrane of erythrocytes was shown by electron microscopy. Ca-gel required more than 10 times as much pre-adsorbed ovalbumin as did Al-gel to inhibit the hemolysis. These results suggest that the hemolytic activity of both adjuvant materials depended mainly on the adsorption ability, and it may be useful to control the adsorption ability of adjuvants to reduce their hemolytic activity.

Adjuvants, Immunologic↗
PubMed1994

Troglitazone prevents the inhibitory effects of inflammatory cytokines on insulin-induced adipocyte differentiation in 3T3-L1 cells.

Tumor necrosis factor (TNF) is implicated in wasting syndromes and insulin resistance in chronic infection and obese-linked diabetes. TNF (10 ng/ml) inhibited adipocyte differentiation of 3T3-L1 cells, and in these TNF treated cells little insulin-stimulated glucose uptake was observed. Treatment of 3T3-L1 cells with troglitazone (1-10 microM) partially prevented this inhibitory effect of TNF on adipogenesis, and enhanced expression of C/EBP alpha and GLUT4, even in the presence of TNF. Troglitazone also prevented the inhibitory effects of interleukin-1, interleukin-6, and leukemia inhibitory factor, but not of transforming growth factor beta on adipocyte differentiation of 3T3-L1 cells. These effects might contribute to the antidiabetic effect of troglitazone in obese diabetic animals.

3T3 Cells↗
PubMed1994

[A case of IgG-kappa type multiple myeloma complicated by Fanconi syndrome].

Fanconi syndrome is characterized by some absorptive defects of proximal renal tubules. It is observed either primarily, or secondarily to various diseases. A case of multiple myeloma complicated by Fanconi syndrome is reported. The patient was a 62-year-old female. The serum total protein was elevated, and monoclonal IgG-kappa protein was found on serum immunoelectrophoresis. Urinary Bence Jones protein was positive. Bone marrow aspiration disclosed increased dysplastic plasma cells, which led to the diagnosis of multiple myeloma. A diagnosis of Fanconi syndrome was based on renal glycosuria, hypophosphatemia, hypokalemia, and panaminoaciduria due to abnormal excretion from the kidney, and metabolic acidosis. After chemotherapy for multiple myeloma, serum IgG level and urine sugar decreased, and serum potassium level was corrected.

Bence Jones Protein↗
PubMed1994

Regulation of lipoprotein lipase synthesis in 3T3-L1 adipocytes by interleukin-11/adipogenesis inhibitory factor.

Interleukin-11/adipogenesis inhibitory factor (IL-11/AGIF) inhibits adipogenesis and suppresses lipoprotein lipase (EC3.1.1.34, LPL) activity in adipocytes (1,2). We investigated the mechanism of suppression of LPL activity in 3T3-L1 adipocytes by IL-11/AGIF. Incubation of adipocytes with 50 ng/ml of IL-11/AGIF led to a 75% decrease in LPL activity within 8 hours, whereas LPL mRNA level decreased by less than 30%. The LPL synthesis, as judged by the incorporation of 35S-label into immunoprecipitable LPL, decreased at almost the same rate over the same time period as enzyme activity. The degradation rate was not significantly affected by IL-11/AGIF. These data suggest that regulation of the synthesis of the enzyme protein is at least one of the main steps in the suppression of LPL by IL-11/AGIF in 3T3-L1 adipocytes.

3T3 Cells↗
PubMed1993

[Human herpesvirus-6 antibodies in idiopathic facial nerve palsy and sudden deafness].

Human herpesvirus-6 (HHV-6) is the causative agent for exanthem subitum. This study investigated the relationship between idiopathic facial nerve palsy (Bell's palsy), sudden deafness and HHV-6 infection. Both Bell's palsy and sudden deafness are syndromes which causes are unknown. Both of them are suspected viral infection as causative agents. Paired sera from 22 patients of Bell's palsy and 39 patients of sudden deafness were examined for reactivity to HHV-6 by the indirect immunofluorescence test. On a case of Bell's palsy and two cases of sudden deafness each of the HHV-6 antibody titers was increased.

Adult↗
PubMed1993

[Involvement of the intraabdominal lymph nodes in a case of subacute necrotizing lymphadenitis].

A 40-year-old woman was admitted to our hospital because of fever, polyposia and polyuria in October 1990. The fasting blood sugar level was 471mg/dl and abdominal CT showed enlargement of the liver, kidneys, and intraabdominal lymph nodes. Although severe diabetes mellitus was controlled with insulin, intraabdominal lymph node swelling continued. Lymph node biopsy was performed under laparotomy. Four from intraabdominal lymph nodes, in addition to one from the left axillary lymph nodes. Four showed findings of non specific lymphadenitis, but one specimen obtained from near the right kidney demonstrated focal necrosis and invasion of macrophages and immunoblasts, which were compatible with the features of subacute necrotizing lymphadenitis (SANL). In SANL, lymphadenopathy is usually observed in the cervical region of young female and the involvement of intraabdominal lymph nodes is quite rare. This patient is the second case of SANL involving an intraabdominal lymph node reported in Japan, and it is suggested that SANL should be considered as a causative disorder of intraabdominal lymphadenopathy.

Abdomen↗
PubMed1992

Artifactual detection of ADP-dependent sucrose synthase in crude plant extracts.

Results presented in a previous report from this laboratory indicated the presence, in crude extracts from sycamore (Acer pseudoplatanus) and spinach (Spinacea oleracea), of a sucrose synthase (EC 2.4.1.13) showing high affinity for ADP as the glucose acceptor in the sucrose-cleaving reaction. In the present paper we report that the modified enzymatic method previously used to measure sucrose synthase activities leads to the detection of artifactual ADP-dependent sucrose synthase, which in fact arises from the combined action of invertase (EC 3.2.1.26) and nucleoside diphosphate kinase (EC 2.7.4.6) activities. We also present data on the partial purification of nucleoside diphosphate kinase from sycamore cells.

Adenosine Diphosphate↗
PubMed1992

A case of trichoadenoma arising in the buttock.

A 41-year-old Japanese man with trichoadenoma on his buttock was described. Histological examination showed numerous horn cysts and some tumor islands consisting entirely of eosinophilic epithelial cells. A review of 24 reported cases of trichoadenoma revealed that most of them developed on the facial region (14 of 24 cases, 58%); the buttock (6 of 24, 25%) was the next most common site.

Adult↗
PubMed1992

[An effective concentration method for human immunodeficiency virus type 1 (HIV-1)].

We designed an effective virus concentration method to prevent the infection with human immunodeficiency virus type 1 (HIV-1) in laboratories. The absorbent of Minicon concentrators (Amicon Division, M.R. Grace & Co.-Conn.) was changed to chitin, a mucopolysaccharide extracted from the shells of Japanese pink crab. HIV-1 in the supernatant of HIV-1 infected Molt-4 cells was concentrated by Minicon and the new concentrators. The new concentrator showed good concentration rate and equality of concentration speed.

Chitin↗