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Biomedical subjects

K Shimada

Publications and source records attributed to K Shimada.

At least 631 records · Page 35Linked to original sources
PubMed1996

Morphology of the lateral ligament in the human temporomandibular joint.

The morphology of the lateral ligament of the human temporomandibular joint is of two types: ligamentous and without distinct structure. Under the scanning electron microscope, a sheath-like structure that contained bundles of collagen was mainly found in the posterior region of the lateral ligament. Analysis of macromolecular components revealed that type III collagen was mainly present on the collagenous framework of the sheath-like structure. Type I collagen, laminin, and tenascin were found in the framework of the sheath-like structure. Supported collagenous bundles and the distribution of macromolecular components might be related to the stability of the temporomandibular joint. The sheath-like structure and other components of the lateral ligaments store energy and protect the capsule from stress and tension during movements of the jaw.

Aged↗
PubMed1996

Isolation and characterization of retinoic acid-inducible cDNA clones in F9 cells: a novel cDNA family encodes cell surface proteins sharing partial homology with MHC class I molecules.

Rae-1 cDNA is one of the retinoic acid (RA) inducible cDNA clones in mouse embryonal carcinoma F9 cells. Rae-1 mRNAs were detected in mouse early embryos, but not in various tissues of adult mice. RAE-1 protein apparently consists of 253 amino acids and is likely to be a glycoprotein consisting of a leader sequence, an extracellular domain, a serine, threonine, proline-rich domain, and a transmembrane domain. Interestingly, it has a weak, but significant homology with major histocompatibility complex (MHC) class I molecules and was immunocytochemically identified as a cell surface protein. By determining partial nucleotide sequences of 17 Rae-1 cDNAs isolated from the RA-induced F9 cells, at least three different kinds of Rae-1 cDNAs were identified and were named Rae-1 alpha, Rae-1 beta, and Rae-1 gamma cDNAs, respectively. As the overall nucleotide sequence homology among these three cDNAs was about 98%, they constitute a novel gene family which is likely to be involved in early mammalian embryogenesis.

Amino Acid Sequence↗
PubMed1996

A catalogue of genes in mouse embryonal carcinoma F9 cells identified with expressed sequence tags.

We used expressed sequence tags (ESTs) to identify genes expressed in mouse embryonal carcinoma F9 cells and prepared 2132 ESTs from undifferentiated F9 cDNA libraries: 1026 were prepared after randomly selecting clones from one of the libraries and the remaining 1106 ESTs were prepared after classifying 2896 clones of the libraries into four classes, according to the levels and patterns of expression. Among the former 1026 ESTs, 797 (78%) matched known genes, 61 (6%) matched database sequences of uncharacterized cDNAs, and 168 (16%) represented novel genes. The ESTs matching known genes were catalogued according to putative structural and cellular functions. As many as 53% were related to transcription and translation, and 19% were related to energy metabolism, including transcripts of mitochondrial DNA. These percentages were significantly higher in F9 cells than in the human heart and brain, and a human liver cell line, HepG2. We found that approximately 7% of the ESTs corresponding to low-abundance mRNAs are either related to retinoic acid-regulated genes or mammalian development- and/or differentiation-related genes. Cataloguing of the genes expressed in the F9 cells paves the way for isolating genes involved in early mammalian development.

Adult↗
PubMed1996

Structural organization of the rae28 gene, a putative murine homologue of the Drosophila polyhomeotic gene.

A putative murine homologue of the Drosophila polyhomeotic gene, named rae28, has been isolated from a genomic library of 129/SV mouse and its structural organization has been analyzed. rae28 is a single gene of approximately 22 kb long and consists of 15 exons. Its 5'-flanking region lacks typical transcriptional regulatory sequences, such as TATA and CCAAT boxes, but contains GC-rich sequences and seven putative binding sites for a transcription factor, Sp1. One major transcription start point has been determined. The overall exon-intron organization suggested that three different Rae28 mRNAs are generated through alternative splicing. Furthermore, the rae28 gene has been located on the R-positive F3 band of mouse chromosome 6 by the direct R-banding fluorescence in situ hybridization methods.

Animals↗
PubMed1996

Genomic structures and characterization of Rae1 family members encoding GPI-anchored cell surface proteins and expressed predominantly in embryonic mouse brain.

Rae1 alpha, Rae1 beta, and Rae1 gamma cDNAs isolated from retinoic acid-treated mouse embryonal carcinoma F9 cells encode cell surface proteins sharing partial homology with MHC class I molecules, and mRNAs corresponding to these cDNAs were detected exclusively in early mouse embryos, especially in the head region. To initiate studies on their roles, the rae1 alpha gene and the genomic DNAs covering the complete coding regions of the rae1 beta and rae1 gamma genes were isolated and their structures were analyzed. Although the coding regions of the three rae1 genes were highly homologous, the restriction map of the 5'-end region of the rae1 alpha gene differed from that of the rae1 beta and rae1 gamma genes. The rae1 family members were mapped by FISH on mouse chromosome 10A4 region. Genomic DNAs hybridizable with a Rae1 cDNA were not detected in rat and human. Rae1 genes were preferentially expressed in early mouse embryos, preferentially in the brain, and RAE1 proteins were anchored on the cell surface by a glycosyl phosphatidylinositol (GPI)-tail, a feature shared by important cell surface ligands.

Animals↗
PubMed1996

Successful radical surgery for an undifferentiated gallbladder carcinoma with lymph node metastases to the mesocolon.

We report successful radical systematic surgery for an undifferentiated gallbladder carcinoma with metastasis to the mesocolonic lymph nodes. The patient, a 70-year-old woman, was admitted with abdominal fullness and appetite loss. Imaging modalities revealed a 10-cm tumor originating from the gallbladder and infiltrating both the liver and transverse colon. As multiple mesocolonic lymph node metastasis was confirmed on laparotomy, right hemicolectomy with systematic lymph node dissection (D3 resection) was performed, in addition to extended cholecystectomy with partial resection of segments 4, 5 and 6 of the liver and distal gastrectomy. Histologically, the tumor was diagnosed as an undifferentiated carcinoma, and metastases were indentified in the mesocolonic lymph nodes (17/50 nodes) but not in the peri-gallbladder lymph nodes (0/16 nodes). The patient has been recurrence-free for 4 years after the operation. This case illustrates that even if gallbladder cancer infiltrates into adjacent organs with regional lymph node metastasis, it is of value to perform radical surgery with systematic lymph node dissection for the involved organs.

Aged↗
PubMed1996

A case of localized pemphigus foliaceus.

Pemphigus foliaceus (PF) is most commonly observed on the face, scalp, chest and back at the onset of the condition. The case described here is that of an 81-year-old female with a single PF lesion localized to the right cheek. A review of the literature published in English and Japanese disclosed only 3 cases of PF in which the patient presented with a single lesion, and 2 of these cases were referred to as "localized pemphigus foliaceus".

Aged↗
PubMed1996

Effect of heavy alcohol intake on long-term results after curative resection of hepatitis C virus-related hepatocellular carcinoma.

We studied the effect of heavy alcohol intake (ethanol intake > or = 80 g/day for > or = 5 yr) on long-term results in 53 patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) who had undergone curative hepatic resection. Cell proliferative activity in the tumor and non-tumorous liver was also assessed by counting argyrophilic nucleolar organizer region-associated proteins (Ag-NOR) in the resected specimens. Twenty patients (20 males, 0 females) were positive for heavy alcohol intake [AI(+)] and 33 (28 males, 5 females) were not [AI(-)]. All patients were positive for HCV antibody and negative for hepatitis B surface antigen. Carcinoma recurred within 3 to 51 postoperative months in 42 (79.2%) of the 53 patients. The median disease-free survival time was 12.6 mo in the AI(+) group and 25.4 mo in the AI(-) group (P < 0.01). The AI(+) group also had significantly poorer survival than the AI(-) group (P < 0.05, 3-year survival rate: 66.7% vs. 93.5%). HCC tumor in the AI(+) group showed significantly increased proliferative activity compared with that in the AI(-) group (P < 0.05, Ag-NOR number: 2.3 +/- 0.8 vs. 1.9 +/- 0.4). However, there was no significant difference between the numbers of Ag-NORs in non-tumorous liver from these two groups (1.5 +/- 0.2 vs. 1.5 +/- 0.2). Patients with heavy alcohol intake should be followed particularly closely, even if they have received curative surgery, since heavy alcohol intake is closely related to a poor postoperative prognosis.

Carcinoma, Hepatocellular↗
PubMed1996

Deletion of Src homology 3 domain results in constitutive activation of Tec protein-tyrosine kinase.

Tec protein-tyrosine kinase (PTK) is the prototype of a new subfamily of non-receptor type PTKs, and is abundantly expressed in hematopoietic tissues. We have revealed that Tec is inducibly tyrosine-phosphorylated and activated by stimulation with a wide range of cytokines. To get more insight into the signaling mechanism through Tec, we have generated a constitutively active form of Tec PTK. Deletion of the Src homology (SH) 3 domain gave rise to a hyperphosphorylated and activated Tec kinase (Tec deltaSH3). The activity of Tec deltaSH3 was confirmed in 293 cells, as well as in cytokine-dependent hematopoietic cells (BA/F3). Tec deltaSH3 should be a useful tool to study the in vivo substrates of Tec PTK.

Animals↗
PubMed1996

Establishment of a hepatocyte cell line producing growth-promoting factors for liver-colonizing tumor cells.

A hepatocyte-derived cell line designated MLE-15A2 was established from a primary culture of mouse hepatocytes. The MLE-15A2 cells appeared to retain the basic nature of hepatocytes in that they showed morphology of an epithelial cell type and secreted albumin into the culture medium. These cells were grown on collagen-coated plates and could be easily expanded to a large-scale culture. Therefore, MLE-15A2 cells may provide a more useful model for studying liver microenvironments than primary cultures of hepatocytes. We found that conditioned media from MLE-15A2 cells, as well as from primary cultures of hepatocytes, promoted the proliferation of highly liver-colonizing colon 26 NL-17 cells better than the poorly liver-colonizing colon 26 NL-4 cells. Moreover, the conditioned media stimulated the growth of some human colon cancer cell lines. These results indicate that MLE-15A2 cells secrete growth factors that selectively stimulate certain tumor cell types. Hepatocyte-derived growth factors may regulate selective survival and colonization of tumor cells in the process of liver metastasis. The growth-promoting activity was unaffected by dialysis, was stable at 80 degrees C for 30 minutes and was bound to a heparin-Sepharose column. The major activity was eluted from the column with 0.7-0.75 M NaCl, and some minor activities eluted with lower concentrations of NaCl. These results suggest that the active components are heterogeneous heparin-binding proteins with lower affinity to heparin than platelet-derived and fibroblast growth factors.

Animals↗
PubMed1996

(1-->3) beta-D-glucan as a quantitative serological marker for Pneumocystis carinii pneumonia.

We detected (1 --> 3) beta-D-glucan (beta-glucan), which is one of the major components of the cyst wall of Pneumocystis carinii, in sera obtained from patients with P. carinii pneumonia (PCP). We confirmed that beta-glucan was detectable by a beta-glucan detection kit (G test; Seikagaku Corporation) in bronchoalveolar lavage fluids (BALFs). The mean concentration of beta-glucan in BALFs obtained from specific-pathogen-free nude mice infected with P. carinii (n = 7; mean, 2,631 [range, 1,031 to 9,095] pg/ml) was significantly higher (P < 0.001) than that in uninfected, specific-pathogen-free mice (n = 7; 6.5 [range, 4.0 to 8.3] pg/ml). The mean level of beta-glucan in BALFs from PCP patients was significantly higher (P < 0.05) than that in BALFs from patients with other lung diseases (7,268 [range, 1,355 to 15,500] pg/ml [n = 4] versus 242.5 [17 to 615] pg/ml [n = 4]). In sera from six of seven patients with PCP, significant levels of beta-glucan (494.1 [8.5 to 1,135] pg/ml) were detected, while it was undetectable in patients with other lung diseases and in a control group. In five patients at follow-up, the level of beta-glucan decreased with clinical improvement. These results suggest that beta-glucan is detectable in sera from patients with PCP and it is a practical serological marker for monitoring of the disease during treatment.

Animals↗
PubMed1996

Human endothelin converting enzyme gene (ECE1) mapped to chromosomal region 1p36.1.

The chromosomal localization of the human endothelin converting enzyme gene (ECE1) has been identified. Southern blot analysis of human genomic DNA from human x mouse somatic cell hybrids demonstrated that ECE1 maps to chromosome 1. Fluorescence in situ hybridization of a digoxigenin-labeled human ECE1 probe to normal human metaphase chromosomes showed that the gene is located within chromosome band 1p36.1.

Animals↗
PubMed1996

Characteristics of the insulin resistance syndrome in a Japanese population. The Jichi Medical School Cohort Study.

We investigated the relationships between hyperinsulinemia (a major indicator of the insulin resistance syndrome), blood pressure, dyslipidemia, and coagulation factors in 2606 community-dwelling Japanese individuals as part of the Jichi Medical School Cohort Study. An age-related decrease of the fasting insulin level was found in men but not in women. Body mass index, systolic and diastolic blood pressure, triglyceride and fasting glucose levels, and factor VII activity all increased in both sexes as the insulin level became higher, while the HDL cholesterol level decreased. In addition, total cholesterol and LDL cholesterol levels increased as the insulin level became higher and lipoprotein(a) levels decreased in the men. Fibrinogen levels were not related to the insulin level in either sex. Multiple logistic regression analysis revealed that fasting insulin levels were positively correlated with body mass index and fasting glucose and factor VII activity levels, whereas they were negatively correlated with HDL cholesterol in both sexes. In addition, fasting insulin levels were positively correlated with LDL cholesterol levels in men and with triglyceride levels in women. Our results indicate that hyperinsulinemia is associated with high factor VII activity in a general Japanese population as well as with high blood pressure and dyslipidemia. The accumulation of these cardiovascular risk factors in hyperinsulinemic subjects appears to contribute to cardiovascular events in the Japanese as well as in westerners.

Adult↗
PubMed1996

Factor VII hyperactivity and endothelial cell damage are found in elderly hypertensives only when concomitant with microalbuminuria.

We studied the relationship among albuminuria, factor VII (FVII) hyperactivity, and endothelial cell damage in 6 elderly hypertensive subjects. The plasma levels of activated FVII (FVIIa), FVII coagulant activity, FVII antigen (FVIIag), von Willebrand factor (vWF), and thrombomodulin were measured to assess FVII hyperactivity and endothelial cell damage, and urinary albumin excretion rate (UAE) was calculated using 12-hour nighttime (7 pm to 7 am) urine collection (mean for 2 consecutive nights). We performed 24-hour ambulatory blood pressure monitoring in all 61 hypertensive patients and classified them into a white-coat hypertension group (n=12) and a sustained hypertension group (n=49). For the levels of FVII, vWF, and thrombomodulin, there were no differences between the white-coat hypertension group and normotensive control subjects (n=25). In the sustained hypertensive group, only the microalbuminuric subgroup (UAE, 15 to 300 microgram/min: n=30) showed significant elevation compared with the normotensive group for the level of FVIIa (mean [95% confidence interval]: 4.0 [3.6 to 4.4] versus 3.0 [2.6 to 3.3] ng/mL, P<.001), the FVIIa/FVIIag ratio (an indicator of activation of FVII zymogen to FVIIa) (1.33 [1.19 to 1.50] versus 1.04 [0.92 to 1.19], P<.01), the level of vWF (188 [165 to 214] % versus 144 [129 to 160] %, P<.01), and thrombomodulin (11.7 [10.3 to 13.3] versus 9.3 [8.5 to 10.3] ng/mL, P<.01). In contrast, none of these levels in the normoalbuminuric hypertensive group (UAE <15 microgram/min, n=19) differed from that in the normotensive control group. These results suggest that among elderly hypertensives, only those with microalbuminuria show enhancement of FVII activation and endothelial cell damage, while patients with white-coat hypertension and normoalbuminuric hypertensives do not show these accompanying abnormalities. Thus, increased levels of FVII activity and markers of endothelial cell damage might account for the higher risk of cardiovascular events in essential hypertension with microalbuminuria.

Aged↗
PubMed1996

Nocturnal fall of blood pressure and silent cerebrovascular damage in elderly hypertensive patients. Advanced silent cerebrovascular damage in extreme dippers.

To study the relation between diurnal blood pressure variations and silent cerebrovascular damage, we performed both 24-hour ambulatory blood pressure monitoring and brain magnetic resonance imaging in 131 elderly asymptomatic hypertensive patients. Silent cerebrovascular damage was identified by the magnetic resonance imaging findings of lacunae (low intensity in T1-weighted images and high intensity in T2-weighted images) and advanced periventricular hyperintense lesions (on T2-weighted images). The frequency of silent cerebrovascular damage in the 100 patients with sustained hypertension was greater than that in the 31 patients with white coat hypertension. We further classified the former group into nondippers (nocturnal reduction of systolic pressure by < 10% of awake systolic pressure; n = 46), dippers (reduction by > or = 10% to < 20%; n = 38), and extreme dippers (reduction by > or = 20%; n = 16). The extent of silent cerebrovascular damage was least severe in the dipper group (P < .05). This J-shaped relation was not found either with the cardiac hypertrophy detected by electrocardiography or with the renal damage assessed by urinary albumin excretion. More than half of the extreme dippers were patients with isolated systolic hypertension, and this prevalence was significantly greater than that in dippers or in nondippers (21% and 30%, respectively). Extreme dippers also had greater variability of pressure (standard deviation of awake systolic pressure) than dippers. Our results indicate that in addition to nondipping, extreme dipping (marked nocturnal fall of blood pressure) should be considered a type of abnormal diurnal blood pressure variation in elderly patients with hypertension who are likely to have advanced silent cerebrovascular damage.

Aged↗
PubMed1996

Adrenomedullin increases inducible nitric oxide synthase in rat vascular smooth muscle cells stimulated with interleukin-1.

We investigated the effects of adrenomedullin on nitric oxide synthesis by measuring the production of nitrite, a stable metabolite of nitric oxide, in cultured rat vascular smooth muscle cells. Incubation of cultures with interleukin-1beta (10 ng/mL) for 24 hours caused a significant increase in nitrite generation. The interleukin-1beta-induced nitrite production by vascular smooth muscle cells was significantly increased by adrenomedullin in a dose-dependent manner (10(-10) to 10(-6) mol/L). This effect of adrenomedullin was significantly inhibited in the presence of Ng-monomethyl-L-arginine. The adrenomedullin-induced nitrite production by interleukin-1beta-stimulated cells was accompanied by increased inducible nitric oxide synthase mRNA accumulation. In the presence of the phosphodiesterase inhibitor isobutylmethylxanthine, interleukin-1beta-induced nitrite accumulation was further increased, but the effect of adrenomedullin was not additive or synergistic. Adrenomedullin dose dependently increased intracellular cAMP levels of vascular smooth muscle cells. These results indicate that adrenomedullin augments nitric oxide synthesis in interleukin-1beta-stimulated vascular smooth muscle cells, at least partially through a cAMP-dependent pathway.

Adrenomedullin↗
PubMed1996

Angiotensin-converting enzyme gene polymorphism in hypertensive individuals with parental history of stroke.

BACKGROUND AND PURPOSE: It has been suggested that the insertion (I)/deletion (D) polymorphism of the angiotensin-converting enzyme (ACE) gene is an independent risk factor for coronary artery disease, but its relation to stroke has not yet been proven. We investigated an association of ACE gene polymorphism with parental history of stroke (PHS) in patients with hypertension. METHODS: We studied 70 hypertensive patients (ambulatory blood pressure > 140/90 mm Hg; age, 59 +/- 11 years) with (n = 27) or without (n = 43) PHS, defined as either one or both parents having had a stroke before 60 years of age. The ACE genotype was analyzed by polymerase chain reaction. RESULTS: Casual blood pressure and mean ambulatory blood pressure levels were not significantly different between patients with and without PHS. The incidence of left ventricular hypertrophy also did not differ significantly between the two groups. However, the frequency of the D allele was significantly higher in patients with PHS (0.72) than in patients without PHS (0.52) (chi 2 = 5.472, P = .019). The frequency of the DD genotype of the ACE gene was also significantly higher in patients with than in those without PHS (DD, 63.0%; ID, 18.5%; II, 18.5% versus DD, 32.6%; ID, 39.5%; II, 27.9%; chi 2 = 6.395, P = .041). CONCLUSIONS: The DD genotype of the ACE gene is associated with PHS in patients with hypertension, which is independent of blood pressure levels or presence of cardiac hypertrophy.

Aged↗