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Biomedical subjects

Y Shimada

Publications and source records attributed to Y Shimada.

At least 469 records · Page 26Linked to original sources
PubMed1993

[Anatomical study on the right bronchial artery for operation of esophageal cancer through right thoracotomy with special reference to the intercostobronchial arteries].

In view of the operative field of esophageal cancer, anatomical findings of the right bronchial arteries were studied in specimens of 71 cadavers. Intercostobronchial arteries were absent only in 3 cadavers (4.2%; group A). As 22.6% of the cadavers had only one intercostobronchial artery supplied as the right bronchial artery (group B), it was considered to be important to preserve this artery. Cadavers both with the intercostobronchial artery and with the other right bronchial-arteries were observed in 70.4% (group C). Right bronchial arteries deriving from the aorta to course similarly to intercostobronchial arteries were present in small number (group D). Further, right bronchial arteries were classified into three types according to the deriving arteries as follows: (I) intercostobronchial arteries, (II) bronchial arteries deriving from the aorta, (III) other right bronchial arteries deriving from right subclavian artery, right inferior thyroid artery or right interthoracic artery. Considering difficulty of the approach from the operative field with right thoracotomy and the anatomical relationship with neighboring organs, it was thought that preserving the type (I) arteries is easy, the type (III) has a possibility to be preserved, and (II) is hard to be preserved. We concluded that preserving intercostobronchial arteries is important in esophageal cancer surgery approached through right thoracotomy because of small number of cadavers without these arteries and ease of preservation.

Adult↗
PubMed1993

Distribution of connectin (titin) and transverse tubules at myotendinous junctions.

The ends of muscle fibers form many longitudinal projections which are further divided into numerous processes and attach to the collagen fibrils of tendons to form myotendinous junctions (MTJs). Immunocytochemical and electron microscopic observations on pectoralis muscles of the chicken revealed the presence of an elastic filamentous protein, connectin (titin), within the terminal sarcomere on the side adjacent to the terminal Z bands, and the absence of connectin and myosin and the presence of actin at the apical sarcoplasmic region of MTJ processes between the terminal Z band and the MTJ sarcolemma. Intermediate voltage electron microscopy showed that T tubules in the terminal sarcomere were absent at the level of the A-I junction on the MTJ side in the rat vastus intermedius, and at the level of the terminal Z band or under the MTJ subsarcolemmal densities in the chicken pectoralis.

Animals↗
PubMed1993

[Anatomic study of the bronchial arteries for operation of esophageal cancer].

In view of the operative field of esophageal cancer, anatomic findings of the bronchial arteries were studied in specimens of 38 cadavers. The number of right and left bronchial arteries were 68 and 61, respectively. The most common branching type was two right and two left arteries, occurring in 36.8% (14/38). Next common type was two right and one left arteries (34.2%). Each specimen had one right intercostobronchial artery and it was considered easy to preserve blood supply to right bronchial artery when cleansing of mediastinal lymphatic chain is performed. But the other 30 right bronchial arteries originating from the aorta coursed, to the area of inferior tracheobronchial lymph nodes, and thus there will be possibility of injury. All of the left bronchial arteries derived from the aorta. The course of 5 left bronchial arteries ran to the area of inferior tracheobronchial lymph nodes, and the one of 41 arteries passed to the area of left tracheobronchial lymph nodes. Therefore, there will be strong possibility of injury to these left bronchial arteries. But the other 19 left bronchial arteries didn't course to any area of lymph nodes, and the arteries can possibly be preserved.

Adult↗
PubMed1993

[A case of primary cardiac hemangiosarcoma].

A case of primary hemangiosarcoma of right atrium was reported. The patient was 43 years old female. She had the symptoms of tamponade due to massive bloody pericardial effusion. Echocardiography, computed tomography, NMR imaging and angiography revealed the precise delineation and extension of tumor, and also allowed diagnosis of hemangiosarcoma. Extirpation of tumor was performed under the cardiopulmonary bypass. The patient was died 3 months later after the operation for liver metastasis. The bloody pericardial effusion seems to be an important symptom of the primary malignant cardiac tumor, and early and precise diagnosis may allow successful operation and long survival of the patients.

Adult↗
PubMed1993

[Trace metal elements in gallstones and their roles].

The concentrations of metal elements in gallstones were measured by absorption spectrometry. Crystallographic analysis by the powder X-ray diffraction method was also performed. For all stones calcium was the major component. In calcium carbonate stones aragonite form, one of the CaCO3 polymorphs and usually unstable in nature, was dominant. As a whole, black-stones contained highest proportions of all metal elements. But these stones were crystallographically grouped into three types; they are calcium carbonate-, calcium phosphate-, and other-one. In each type, the concentration of metal element differed greatly. It is suggested that in black-stones the amount of Mn is remarkable and Cu is highly correlated to black residue. It was true, but Mn was remarkable especially in calcium phosphate-type and Cu was the highest in other-type.

Bilirubin↗
PubMed1993

[Clinical application of recombinant human SOD for the protection of ischemia reperfusion injury during open heart surgery].

We have applied recombinant human superoxide dismutase (RH-SOD) to prevent ischemia reperfusion injury in the patients who received open heart surgery. Twenty-four patients were divided into 2 groups; group A had no treatment as control and group B received bolus injection of RH-SOD (35,000 IU/kg) into cardiopulmonary bypass 5 minutes before reperfusion. Arterial and coronary sinus blood was collected to measure chemiluminescence (ChL) value, SOD activity, lactate and pyruvate level, and several parameters of myocardial oxygen metabolism after reperfusion. Arterio-venous difference of ChL value showed the tendency of less ChL generation of the heart in group B compared with those in group A. But no other parameters showed significant difference between the two groups. Our data suggested that this way of the administration of RH-SOD failed to improve the myocardial protection during open heart surgery. Further investigation, such as dose response study, might be required to determine whether RH-SOD possess beneficial effects or not in the clinical setting.

Heart Arrest, Induced↗
PubMed1992

Tissue selectivity of pravastatin sodium, lovastatin and simvastatin. The relationship between inhibition of de novo sterol synthesis and active drug concentrations in the liver, spleen and testis in rat.

Tissue selectivity of pravastatin sodium (pravastatin), lovastatin and simvastatin, 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors was examined by measuring inhibition of de novo sterol synthesis and active drug concentrations in the liver, spleen and testis in rats after a single oral administration (25 mg/kg) of these drugs. Regarding tissue drug concentrations, all three drugs were liver selective: concentrations of drugs in the liver were about ten-times higher than those in the spleen and testis. On the other hand, pravastatin was far more liver selective in inhibiting sterol synthesis than two other inhibitors: pravastatin inhibited de novo sterol synthesis in the liver but minimally in the spleen and testis, whereas lovastatin and simvastatin inhibited in all three tissues. Microautoradiographic and in vitro cellular-uptake studies demonstrated that pravastatin remained in the extracellular space in the spleen, whereas the other drugs entered the cell. We conclude that pravastatin exhibits a liver-selective inhibition of sterol synthesis because the agent permeates the cell membrane in the liver, but not in non-hepatic tissues.

Animals↗
PubMed1992

Oligo(2'-O-methyl)ribonucleotides. Effective probes for duplex DNA.

To find novel probes for duplex DNA, we prepared four types of triplexes containing a homopurine-homopyrimidine 15-mer duplex DNA, and examined their thermal stabilities (Tm values). The single strand used for triplex formation were a DNA 15-mer having a defined C-T mixed sequence, and its sugar-modified analogs, namely 2'-fluoro DNA, RNA, and 2'-O-methyl RNA. The 2'-O-methyl RNA and the RNA-containing triplexes were similar in their enhanced stabilities at pH 6.1 and, amongst the four triplexes, the 2'-O-methyl was the most stable at pH 5.0. Furthermore, an experiment using a 34-mer duplex DNA suggested that the 2'-O-methyl RNA-triplex was destabilized, mostly as a result of the incorporation of a mismatched triplet, as compared to the DNA triplex counterpart. Thus, 2'-O-methyl RNA can serve as an effective probe for duplex DNA.

Base Sequence↗
PubMed1992

Expression of the interleukin-3 and granulocyte-macrophage colony-stimulating factor genes in Friend spleen focus-forming virus-induced erythroleukemia.

Friend spleen focus-forming virus (F-SFFV) is a replication-defective retrovirus that induces a multistage erythroleukemia in mice. In the first stage, expression of the SFFV envelope glycoprotein results in erythroid hyperplasia. Subsequently, the F-SFFV integrates near the Spi-1 gene and activates its expression, resulting in immortalized cells that represent a second stage in the disease process. We report here that media conditioned by erythroleukemia cell lines or leukemic spleen cells induced by the polycythemia-inducing strain of F-SFFV (F-SFFVp), but not medium conditioned by SFFVp-induced hyperplastic spleens, promote the proliferation of normal granulocyte-macrophage progenitor cells and of granulocyte-macrophage colony-stimulating factor (GM-CSF)- and/or interleukin-3 (IL-3)-dependent cell lines. The colony-stimulating activity of the conditioned media from four of five of the lines studied was neutralized by antibodies specific for IL-3 and/or GM-CSF, and IL-3 and GM-CSF-specific mRNA could be detected in the cells after amplification by the polymerase chain reaction. No rearrangements of the IL-3 or GM-CSF genes were observed by Southern blot analysis. However, as previously shown for SFFV-induced cell lines, the Spi-1 gene was expressed in all of these cells. Because the Spi-1 gene encodes a transcription factor whose cognate sequences are present in the promoter region of many hematopoietic growth factor genes, including IL-3 and GM-CSF, Spi-1 activation may be inducing the expression of these genes.

Animals↗
PubMed1992

Extracellular pH modulates N-methyl-D-aspartate receptor-mediated neurotoxicity and calcium accumulation in rat cortical cultures.

The effect of extracellular pH (pHo) on the excitotoxicity of N-methyl-D-aspartate (NMDA) in cultured rat cortical cells was studied. Treatment of cells with 500 microM NMDA for 15 min at various pH's in a range from 6.5 to 8.0 progressively enhanced staining with Trypan blue and release of lactate dehydrogenase with increased pH after 18 h of culture following treatment. The cytotoxic effect of high concentration of K+ (40 mM) or veratridine (10 microM) was also directly related to the increase in pHo. Free calcium accumulation in cells on addition of NMDA increased parallel to pHo. Changes in intracellular pH were estimated to be minor compared with extracellular changes. Specific NMDA antagonists could block both the NMDA- and membrane depolarization-induced neurotoxicity and calcium accumulation completely. These results suggest that the proton concentration outside of cells attenuates NMDA-induced neurotoxicity by blocking calcium accumulation.

Animals↗
PubMed1992

Intercellular junctions in embryonic chick cardiac muscle revealed by rapid freezing and freeze-substitution.

Using the method of rapid freezing and freeze-substitution, the embryonic chick cardiac muscle was investigated by transmission electron microscopy. Initially, the intercellular junctional complexes (fasciae adherentes and desmosomes) were formed in close proximity to each other along a nearly straight line. Subsequently, the separation of fasciae from desmosomes took place to form intercalated discs. The cell membranes of fasciae adherentes were reinforced with highly interwoven fine fibrils at which myofibrils terminated. The intercellular space of fasciae was bridged with fine fibrillar structures seemingly connected by a thin line at their middle portions. In the intercellular space of desmosomes, central lamina and traversing filaments were clearly observed. The outer and inner leaflets of the desmosomal plasmalemma were asymmetrically differentiated; the outer leaflet was thinner than the inner leaflet. On the inner side of the cell membrane, an electron-lucent layer and a dense desmosomal plaque were observed. The latter structure had protrusions with less electron density towards the cytoplasmic side. Further inside, a meshwork of fine fibrils was seen along and toward which bundles of intermediate filaments ran. The results obtained with freeze-substitution appeared to provide more information than those with thin sections after conventional fixation or with replicas of chemically fixed/glycerinated or physically fixed/deep-etched materials.

Animals↗
PubMed1992

Characterization of 21 newly established esophageal cancer cell lines.

Twenty-one esophageal cancer cell lines (KYSE series) have been established from the resected specimens of patients with esophageal cancer. Three lines, KYSE-30, KYSE-50, and KYSE-70, were derived from the implanted tumor of nude mice (initial passage); others were derived from resected specimens. Each cell line was morphologically distinct. Detailed cytogenetic analysis indicated that each cell line was karyotypically unique, and DNA fingerprint analysis showed no cross-contamination among cells. Doubling time ranged from 13.7 to 75.5 hours, and modal chromosome numbers ranged from 46 to 120. Most cell lines grew in monolayer, but two cell lines (KYSE-50 and KYSE-360) grew as floating cell aggregates. No correlation was demonstrated between the establishment of cell lines and cell differentiation. These cell lines are the first reported to be homogeneous and individually unique and may provide a useful model for the study of human esophageal cancer.

Animals↗
PubMed1992

Usefulness of preoperative low dose cisplatin treatment for advanced esophageal cancer.

In order to decrease the perioperative complications by preoperative cisplatin chemotherapy, the preoperative single administration of cisplatin (30 mg/m2) was performed weekly from one to six times in 36 consecutive patients with esophageal cancer classified as higher than Stage II. The survival curve of 17 patients in Stage III was significantly better (P < 0.05) than that of patients who had been treated without preoperative cisplatin treatment. In 3 of the 12 patients who had locally invasive cancer, either the main tumors or the metastatic lymph nodes, which had invaded the trachea or the left main bronchus, sufficiently receded, so that a curative esophagectomy became possible; 2 of them have survived over 33 months while 1 died of pneumonia 33 months after surgery. The number of perioperative complications was minimal, and thus, we consider that the postoperative use of cisplatin and fluorouracil is indicated in patients in whom a histological response is noted in the resected specimens.

Aged↗
PubMed1992

Hemodynamic changes after resection of thoracic duct for en bloc resection of esophageal cancer.

An en bloc resection of esophageal cancer is one of the most radical forms of esophagectomy, and includes the resection of the thoracic duct, but a relatively high hospital mortality rate has been reported. There is very little knowledge on the pathophysiological changes after resection of the thoracic duct. We examined 24 patients who underwent en bloc resection. Some patients developed severe tachycardia or shock postoperatively which subsided after a massive infusion of plasma. Analysis of the fluid balance revealed that much more fluid was necessary during surgery and the postoperative 24 h than in patients treated by a standard esophagectomy. Postoperative lymphangiography or CT revealed abnormal collateral lymphatics around the kidneys or in the pelvic cavity. This suggests the development of the lymphaticovenous shunts, which differed depending on the anatomy of each patient. One patient with chronic hepatitis developed uncontrollable ascites. These are important findings which can hopefully reduce the high rate of hospital death after this operation.

Aged↗
PubMed1992

Multiple cis-acting DNA elements that regulate transcription of the adenovirus 12 E1A gene.

To delineate cis-acting elements for adenovirus (Ad) 12 E1A gene transcription, we transfected HeLa and NIH3T3 cells with DNAs having various deletions in the 5'-upstream region linked to the chloramphenicol acetyltransferase gene. Deletions in the regions between nucleotide (nt) positions 54 and 166, and 167 and 200, with respect to the left end of the viral genome at nt position 1, caused a two- to three-fold reduction in transcription. Transcription decreased to an almost undetectable level with loss of the region between nt positions 201 and 282. The effect of these mutations was almost consistent between both cell lines. The region between nt positions 77 and 94 stimulated transcription when situated upstream of the simian virus 40 early promoter in either orientation. Transcription was stimulated about ninefold in the presence of the DNA that encodes the product of the 13S, but not the 12S mRNA of the Ad12 E1A gene. These results indicate that transcription of the Ad12 E1A gene is regulated by multiple cis-acting elements and is stimulated by its own gene product.

3T3 Cells↗