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Biomedical subjects

S Yamashiro

Publications and source records attributed to S Yamashiro.

At least 55 records · Page 3Linked to original sources
PubMed1999

[An analysis of fever of unknown origin defined by newly proposed practical criteria. A prospective study of 56 cases].

The criteria proposed by Petersdorf has been in use internationally to define the fever of unknown origin (FUO) since 1961 and the research of FUO has progressed with this criteria. Mean-while, new diagnostic methods have been developed and illness behavior of febrile patients has changed considerablly. Accordingly, the definition by Petersdorf is becoming less matched to current clinical situation. Therefore, we have developed a new practical criteria of FUO; i.e., out-patients who are febrile more than 2 weeks, documented temperature higher than 37.5 degrees C at least on one occasion and undetermined diagnosis and in-patients who are febrile more than 1 week with documented temperature higher than 37.5 degrees C, and undetermined diagnosis. Between October 1, 1993, and October 31, 1996, we prospectively collected a series of febrile patients who fulfilled our new criteria. We identified 56 patients by our criteria (23 male and 33 female, age: 49.7 +/- 20.6. range 15 to 88). Of this 56 patients, 19 (32%) were found to have infections, 18 (31%) had collagen disorders, 5 (9%) had malignancy and 6 (10%) had died. Of 56 patients, 38 (68%) were in the newly added group. Of these 38 patients, 4 patients had subacute necrotizing lymphoadenitis, 4 cytomegalovirus infection, 3 polymyalgia rheumatica, 3 tuberculosis. Four patients (10%) died. With our criteria, febrile patients who previously had not been included were found to have as poor a prognosis as with the Petersdorf group.

Adolescent↗
PubMed1999

Molecular cloning of the guinea pig GRO gene and its rapid expression in the tissues of lipopolysaccharide-injected guinea pigs.

BACKGROUND: CXC chemokines, IL-8 and GRO, play a role in the recruitment of neutrophils in the human. The functional orthologues in the rat and mouse are CINC/KC and MIP-2. The lack of IL-8 made these animals less useful to study the role of IL-8 and GRO. METHODS: Guinea pig (gp) cDNA libraries were screened for GRO and IL-1beta. A gp genomic library was screened with a gpGRO cDNA probe. Expression of gpIL-8, gpGRO, gpTNFalpha, and gpIL-1beta was investigated by Northern analysis and/or by in situ hybridization. RESULTS: Two gpGRO cDNAs, a 3.0-kb gpGRO genomic DNA, and a gpIL-1beta cDNA were cloned. gpGRO and gpIL-8 mRNA were detected in different tissues including lungs 1 h after intraperitoneal injection of lipopolysaccharide (LPS) into guinea pigs. gpGRO, gpIL-8, gpTNFalpha, and gpIL-1beta expression peaked at 3 h in the lungs. Both gpGRO and gpIL-8 mRNA were detected in the cells in alveolar spaces and bronchial epithelial cells. However, gpGRO mRNA, but not gpIL-8, was also expressed in endothelial cells and vascular smooth muscle cells. CONCLUSIONS: gpGRO and gpIL-8 mRNA rapidly accumulated in the lungs of guinea pigs after LPS injection. Expression of gpIL-8 and gpGRO mRNA appeared to be independent from TNFalpha- or IL-1beta-stimulation in this model. A high level expression of gpGRO in vascular cells suggest an important role of GRO in the sequestration of neutrophils and multi-organ injuries induced by LPS. The guinea pig will provide an excellent model to study the roles of IL-8 and GRO, important inflammatory mediators in the human.

Amino Acid Sequence↗
PubMed1999

[Evaluation of the results of the combined maze procedure for chronic atrial fibrillation with organic heart disease].

To examine the surgical indications and the results of the maze procedure, we reviewed 30 cases who underwent the maze procedure concomitantly with other open heart surgery from October 1995 to October 1997.: the average age was 60.9 years (37 to 75 years) and mean follow up period was 12.3 months (1 to 25 months). The modified maze procedure described by Kosakai and associates was applied in all patients. Twenty one patients (72.4%) regained atrial rhythm and eight patients (27.6%) sustained atrial fibrillation in the follow up periods. The left atrial diameter measured by echocardiography and cardiothoracic ratio were significantly larger in the latter group of patients, compared with those who recovered normal sinus rhythm (63.8 +/- 19.5 versus 51.2 +/- 7.8 mm and 67.7 +/- 8.1 versus 59.2 +/- 5.4%). In order to perform the combined maze procedure, cardiac arrest time and cardiopulmonary bypass time were extended for 56.9 minutes and 65.9 minutes, respectively, compared with the cases without a maze procedure. Four patients (brady atrial fibrillation 2, brady junctional rhythm 1, and complete AV block 1) required permanent pacemaker implantation. There was no operative death, but one patient who underwent the maze procedure and AVR + MAP + TAP died after 4 months due to pulmonary infection, sepsis and multiple organ dysfunction. This patient had shown low output syndrome for 3 days postoperatively. Having considered the data that the preoperative ejection fraction was 51%, cardiopulmonary bypass and cardiac arrest time were 200 min and 165 min respectively, occurrence of low cardiac output had been influenced by prolonged aortic cross-clamp. No late deaths have been observed in follow up period. In conclusion, maze procedure should not be performed in patients who have enlarged left atrium or complex cases requiring relatively longer operative time.

Adult↗
PubMed1999

Mast cells of the bovine trachea: staining characteristics, dispersion techniques and response to secretagogues.

Sections of the lower trachea of cattle, fixed in either Carnoy's or formalin, were stained with toluidine blue, alcian blue, or alcian blue and safranin O to study the mast cell population. After toluidine blue staining, about twice as many cells in tissue fixed in Carnoy's contained dark blue granules compared with tissue fixed in formalin. In addition, for the first time in cattle, a population of cells containing red granules was identified after staining with alcian blue and safranin O. Most of these red granules were formalin sensitive. An enzymatic dispersal technique for mast cells is described that yielded 9.4+/-0.4% mast cells (percentage of nucleated cells) with a viability of 92.3+/-0.6%. Spontaneous histamine release was 3.3+/-0.8%. Dispersed mast cells were challenged with various immunological and nonimmunological secretagogues. The calcium ionophores, A23187, ionomyocin, and BrX537A, were effective in releasing up to 94% of histamine in mast cells in a dose-response relationship. Pasteurella haemolytica culture supernate caused about 10% histamine release at a dose of 0.5 mg/mL after correction for spontaneous release. The average histamine content of the mast cells was 6.6+/-1.0 pg/cell. Cytospins of dispersed cells fixed in Carnoy's and stained with alcian blue and safranin O contained mast cells with blue and red granules, and a few cells with a mixture of both granule types. Based on the effects of type of fixation, staining characteristics and histamine content, a mix of subtypes of mast cells is present in the bovine trachea. However, functionally they respond to secretagogues differently than rodent mast cells. Without an immunological secretagogue, studies to determine compounds that will be effective in blocking mast cell degranulation will be limited.

Animals↗
PubMed1998

Complex gangliosides are essential in spermatogenesis of mice: possible roles in the transport of testosterone.

Mice, homozygous for disrupted ganglioside GM2/GD2 synthase (EC 2.4. 1.94) gene and lacking all complex gangliosides, do not display any major neurologic abnormalities. Further examination of these mutant mice, however, revealed that the males were sterile and aspermatogenic. In the seminiferous tubules of the mutant mice, a number of multinuclear giant cells and vacuolated Sertoli cells were observed. The levels of testosterone in the serum of these mice were very low, although testosterone production equaled that produced in wild-type mice. Testosterone was found to be accumulated in interstitial Leydig cells, and intratesticularly injected testosterone was poorly drained in seminiferous fluid in the mutant mice. These results suggested that complex gangliosides are essential in the transport of testosterone to the seminiferous tubules and bloodstream from Leydig cells. Our results provide insights into roles of gangliosides in vivo.

Animals↗
PubMed1998

Regulation of actin binding and actin bundling activities of fascin by caldesmon coupled with tropomyosin.

Human fascin is an actin-bundling protein and is thought to play a role in the formation of microfilament bundles of microspikes and stress fibers in cultured cells. To explore the regulation of fascin-actin interaction, we have examined the effects of culture cell caldesmon and tropomyosin (TM) on actin binding activity of human fascin. Caldesmon alone or TM alone has little or no effect on the actin binding of fascin. However, caldesmon together with TM completely inhibits actin binding of human fascin. When calmodulin is added, the inhibition of fascin-actin interaction by caldesmon and TM becomes Ca2+ dependent because Ca2+/calmodulin blocks actin binding of caldesmon. Furthermore, as phosphorylation of caldesmon by cdc2 kinase inhibits actin binding of caldesmon, phosphorylation can also control actin binding of fascin in the presence of TM. As expected by the inhibition of fascin-actin binding, caldesmon coupled with TM also inhibits actin bundling activity of fascin. Whereas smooth muscle caldesmon alone or TM alone shows no effect, caldesmon together with TM completely inhibits actin bundling activity of fascin. This inhibition is again Ca2+ dependent when calmodulin is added to the system. These results suggest important roles for caldesmon and TM in the regulation of the function of human fascin.

Actins↗
PubMed1998

Positive regulation of the human macrophage stimulating protein gene transcription. Identification of a new hepatocyte nuclear factor-4 (HNF-4) binding element and evidence that indicates direct association between NF-Y and HNF-4.

We previously reported that the transcription of the human macrophage stimulating protein (MSP) gene was positively regulated by the binding of NF-Y to the CAATT sequence in the promoter region of this gene. Here we confirmed our previous results and further characterized the MSP promoter. Luciferase assay with deletion constructs showed the importance of the region, +32 to +39, for the promoter activity in Hep3B cells. Two nuclear protein-DNA probe (+15 to +40) complexes, C1 and C2, were detected by electrophoretic mobility shift assay. C2 was specific to hepatoma cells and contained hepatocyte nuclear factor-4 (HNF-4). DNase I footprinting with recombinant HNF-4 located another HNF-4-binding site in the distal region, -89 to -54. Mutations in the CAATT or the proximal HNF-4-binding site significantly reduced the promoter activity in Hep3B cells and HNF-4-transfected HeLa cells, whereas mutations in the distal HNF-4-binding site had no effect. The close proximity between the CAATT and the proximal HNF-4-binding site suggested that a direct contact between NF-Y and HNF-4 might be important. Protein-protein interaction between the A-subunit of NF-Y and HNF-4 was detected by a yeast two-hybrid system. The binding of in vitro translated HNF-4 to immobilized NF-YA and in vitro translated NF-YA to immobilized HNF-4 was also detected. These results suggest the binding of HNF-4 to the proximal HNF-4-binding site directs the basal transcription of the MSP gene, and the maximal promoter activity may depend on the direct association between HNF-4 and NF-Y.

Base Sequence↗
PubMed1998

Specific localization of serine 19 phosphorylated myosin II during cell locomotion and mitosis of cultured cells.

Phosphorylation of the regulatory light chain of myosin II (RMLC) at Serine 19 by a specific enzyme, MLC kinase, is believed to control the contractility of actomyosin in smooth muscle and vertebrate nonmuscle cells. To examine how such phosphorylation is regulated in space and time within cells during coordinated cell movements, including cell locomotion and cell division, we generated a phosphorylation-specific antibody. Motile fibroblasts with a polarized cell shape exhibit a bimodal distribution of phosphorylated myosin along the direction of cell movement. The level of myosin phosphorylation is high in an anterior region near membrane ruffles, as well as in a posterior region containing the nucleus, suggesting that the contractility of both ends is involved in cell locomotion. Phosphorylated myosin is also concentrated in cortical microfilament bundles, indicating that cortical filaments are under tension. The enrichment of phosphorylated myosin in the moving edge is shared with an epithelial cell sheet; peripheral microfilament bundles at the leading edge contain a higher level of phosphorylated myosin. On the other hand, the phosphorylation level of circumferential microfilament bundles in cell-cell contacts is low. These observations suggest that peripheral microfilaments at the edge are involved in force production to drive the cell margin forward while microfilaments in cell-cell contacts play a structural role. During cell division, both fibroblastic and epithelial cells exhibit an increased level of myosin phosphorylation upon cytokinesis, which is consistent with our previous biochemical study (Yamakita, Y., S. Yamashiro, and F. Matsumura. 1994. J. Cell Biol. 124:129-137). In the case of the NRK epithelial cells, phosphorylated myosin first appears in the midzones of the separating chromosomes during late anaphase, but apparently before the formation of cleavage furrows, suggesting that phosphorylation of RMLC is an initial signal for cytokinesis.

Amino Acid Sequence↗
PubMed1998

[An evaluation of cases carried out by both root reconstruction using Carrel patch method and concomitant procedure].

During the past 7 years from January 1991 to November 1997, we experienced 31 cases of aortic root reconstruction utilizing Carrel patch method. Concomitant procedure were performed in 9 cases of them due to another cardiovascular disease. Complicated cardiovascular disease included 3 cases of ischemic heart disease, 3 cases mitral regurgitation and one case of Aortic arch aneurysm. Several concomitant procedures were performed; 5 cases of CABG, 2 cases of mitral annuloplasty, one case of CABG with mitral valve replacement and one case of aortic arch replacement. The mean extra corporeal circulation time was 190.6 +/- 39.3 minutes and aortic clamp time was 147.8 +/- 34.2 minutes in these 9 cases. There were no significant differences of operative results between the simple root reconstruction group and the concomitant procedure group. We concluded that the aortic root reconstruction using the Carrel patch method has few complications. Although further long-term follow-up is required, our experiences suggest that the aortic root reconstruction with the concomitant procedure can be carry out safely with the aid of appropriate assistance method.

Adult↗
PubMed1998

[Separate operation for extensive aneurysm (mega-aorta) complicated with ischemic heart disease].

A seventy one year-old woman, who had an arch and thoracoabdominal aortic aneurysm (type II according to Crawford classification) with ischemic heart disease, underwent a separate operation using the elephant trunk method. At first, she underwent the ascending aorta and arch replacement the with elephant trunk technique, and, underwent CABG simulutaneously utilizing the separate extra corporeal circulation and hypothermic circulatory arrest. The Chest and abdominal CT revealed the enlargement of abdominal aortic aneurysm 5 months after operation. The second operation was performed using Stoney's spiral opening method and the revasculization of spinal arteries (Th6, 7 and Th9) underwent the segmental aortic clamping to prevent spinal cord ischemia. Furthermore, the second operation was performed using selective perfusion to visceral arteries and F-F bypass for the prevention of visceral ischemia. Each flow rate by selective perfusion in major abdominal blanches was from 50 to 100 ml/min. Therefore, hepatorenal dysfunction and paraparesis did not occur after the second operation. It was suggested that the segmental aortic clamping and the selective perfusion to visceral arteries with F-F bypass may be effective to prevent the ischemia of the spinal cord and abdominal organs.

Aged↗
PubMed1998

[A case of traumatic aneurysm of the brachiocephalic artery].

Traumatic aneurysm of the brachiocephalic artery is rate. We presented a case of traumatic aneurysm of the brachiocephalic artery caused by traffic accident. A 28-year-old woman suffered a blunt chest trauma. A chest X-ray revealed a widening of the superior mediastinum and multiple rib fractures. CT scanning demonstrated left hemothorax with lung contusion and upper mediastinal hematoma. An aortography was performed which showed aneurysmal dilatation at the origin of the brachiocephalic artery. The patient underwent an operation 24 hours after chest injury. An aorto-right common carotid artery and right subclavian artery bypass with bifurcated Dacron graft was performed while monitoring temporary artery pressure. After resection of aneurysm, We found that about 3 cm longitudinal laceration of intima on the posterior wall of brachiocephalic artery. Her post operative condition was good and no neurological defect was noted.

Accidents, Traffic↗
PubMed1998

Fascin, an actin-bundling protein, induces membrane protrusions and increases cell motility of epithelial cells.

Fascin is an actin-bundling protein that is found in membrane ruffles, microspikes, and stress fibers. The expression of fascin is greatly increased in many transformed cells, as well as in specialized normal cells including neuronal cells and antigen-presenting dendritic cells. A morphological characteristic common to these cells expressing high levels of fascin is the development of many membrane protrusions in which fascin is predominantly present. To examine whether fascin contributes to the alterations in microfilament organization at the cell periphery, we have expressed fascin in LLC-PK1 epithelial cells to levels as high as those found in transformed cells and in specialized normal cells. Expression of fascin results in large changes in morphology, the actin cytoskeleton, and cell motility: fascin-transfected cells form an increased number of longer and thicker microvilli on apical surfaces, extend lamellipodia-like structures at basolateral surfaces, and show disorganization of cell-cell contacts. Cell migration activity is increased by 8-17 times when assayed by modified Boyden chamber. Microinjection of a fascin protein into LLC-PK1 cells causes similar morphological alterations including the induction of lamellipodia at basolateral surfaces and formation of an increased number of microvilli on apical surfaces. Furthermore, microinjection of fascin into REF-52 cells, normal fibroblasts, induces the formation of many lamellipodia at all regions of cell periphery. These results together suggest that fascin is directly responsible for membrane protrusions through reorganization of the microfilament cytoskeleton at the cell periphery.

Actin Cytoskeleton↗
PubMed1998

Intradermal injection of monocyte chemoattractant protein-1 induces emigration and differentiation of blood monocytes in rat skin.

BACKGROUND: Monocyte chemoattractant protein-1 (MCP-1) is a potent chemoattractant for blood monocytes in vitro. Recent studies in MCP-1-transgenic mice revealed that the local production of MCP-1 caused monocyte infiltration. However, the kinetics of monocyte infiltration after the production of MCP-1 or the amount of MCP-1 necessary for monocyte recruitment are not known. METHODS: We purified recombinant rat MCP-1 expressed in COS-7 cells, and injected it into rat skin. The infiltrating cells were examined by immunohistochemistry and ultrastructural peroxidase cytochemistry. RESULTS: Rat recombinant MCP-1 had a molecular mass of approximately 30 kD and exhibited the peak monocyte chemotactic activity at 10(-9) M. One microgram of MCP-1 caused intra- and extravascular accumulation of mononuclear cells 3 h after injection. The cells were ED1+, indicating they were blood monocytes. The infiltration of mononuclear cells peaked at 12-24 h, and most of them were TRPM-3+ and ED3+, characteristic to exudate macrophages. None of the cells expressed ED2 or Ki-M2R antigens, markers for resident macrophages, until 3 days after injection. There was no uptake of [3H]thymidine by the infiltrating cells. Ultrastructural peroxidase cytochemistry confirmed that the infiltrating cells were monocytes and exudate macrophages. The number of OX8+ lymphocytes also peaked at 12 h, consisting of approximately 9% of the total infiltrating cells. CONCLUSION: These results indicate that MCP-1 attracts blood monocytes as early as 3 h and the infiltrating monocytes differentiate into exudate macrophages in loco. However, this effect was transient and the infiltration of monocytes did not result in tissue damage.

Animals↗
PubMed1998

Alterations in fascin-expressing germinal center dendritic cells in neoplastic follicles of B-cell lymphomas.

Germinal center dendritic cells (GCDCs) have essential functions in retention of immune complexes within secondary follicles, B-lymphocyte antigenic stimulation, B-cell activation, homing of B-cells via adhesion molecules such as ICAM-1 and VCAM-1, and B-cell survival via apoptosis. The neoplastic cells of follicular lymphomas (FLs) are thought to derive from follicular B lymphocytes, but their relationship to GCDCs remains unclear. This study used immunohistochemical staining for fascin, a 55-kDa actin-bundling protein strongly expressed in GCDCs and their processes, to evaluate their distribution in neoplastic follicles. Forty-two cases of B-cell FL were evaluated, and immunoreactive staining for fascin was compared with six cases of Castleman's disease (CD) and six cases of follicular hyperplasia. FLs generally revealed decreased or absent fascin-staining GCDCs, suggesting loss of fascin expression by dendritic cells in neoplastic follicles compared with hyperplastic follicular centers. In some follicles, there was partial retention of dendritic architecture with islands of residual syncytial network. Interdigitating reticulum cells in the parafollicular regions revealed normal fascin expression with intense staining of dendritic processes. In contrast with FLs, cases of follicular hyperplasia revealed normal or increased fascin-positive follicular dendritic cells, and in cases of hyaline vascular CD, follicular dendritic cells revealed tight syncytial networks. These results suggest that GCDCs are deficient in neoplastic follicles, compared with benign reactive or hyperplastic follicles. This alterations in the germinal center microenvironment might explain the inability of FL cells to present antigen to T lymphocytes and to mount an effective antitumor immune response.

Carrier Proteins↗
PubMed1998

Alterations in blood platelet morphology during aggregate formation in the Asian elephant (Elephas maximus).

The ultrastructure of Asian elephant (Elephas maximus) platelets before and after activation with the agonist platelet activating factor (PAF) was studied. The unactivated platelet has a distinct ultrastructural appearance: the cytoplasm contains large randomly distributed granules but lacks the internal cristae that typify the open canalicular system in many types of mammalian platelets. Following PAF stimulation, large platelet aggregates form, but many platelets remain discrete, with little evidence of pseudopod formation or fusion of membranes. Two types of platelets are visible within the aggregates: those that are morphologically intact and those with gaplike features on the outer membrane and that have become degranulated, appearing as empty swollen sacs. The lack of platelet membrane fusion within the aggregates may permit the reversal of aggregation that is a characteristic response of elephant platelets to PAF.

Animals↗
PubMed1997

In vivo study of halothane hepatotoxicity in the rat using magnetic resonance imaging and 31P spectroscopy.

Using magnetic resonance imaging (MRI) and spectroscopy (MRS), in vivo halothane hepatotoxicity was assessed in male Wistar rats. With 1.5% halothane in 100 or 20% O2, an edematous region, characterized by increased intensity on T2 weighted images and an increase in regional tissue water content (rho water), was seen proximal to the hepatic portal vein in the liver. Both spin-lattice relaxation (T1) and spin-spin relaxation (T2) increased in this region, relative to distal regions of the liver. Similarly, a high signal intensity on proton density weighted images was observed in this area. As halothane anaesthesia progressed, a decrease in the adenosine triphosphate-inorganic phosphate ratio (ATP/Pi) and an increase in the phosphomonoester-phosphodiester (PME/PDE) ratio was detected in the liver. In addition, intracellular pH decreased and intracellular free magnesium concentration [Mg2+] increased with time of exposure. Excessive vacuolation, ribosomal disappearance from rough endoplasmic reticulum, mitochondrial swelling and fragmentation of smooth endoplasmic reticulum were observed by transmission electron microscopy (TEM) in samples from the edematous region of the liver.

Anesthetics, Inhalation↗