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Biomedical subjects

A Tamura

Publications and source records attributed to A Tamura.

At least 307 records · Page 17Linked to original sources
PubMed1993

Detection of thrombomodulin in human lung cancer cells.

Thrombomodulin (TM), which usually exists in vascular endothelial cells and exerts an anticoagulant activity, was detected by Western blot analyses and immunocytochemical staining using three anti-TM monoclonal antibodies in cultured cell lines derived from a squamous cell carcinoma and an adenocarcinoma of the lung, but was not detected in a cell line derived from a small cell carcinoma. Functional assays indicated that TM detected in these cells was functionally active. The presence of TM in 22 specimens of surgically removed lung cancer tissue was also examined by an immunohistochemical method. TM was present along the cell membranes in 4 (36%) of 11 squamous cell carcinomas examined, but was not detected in 10 adenocarcinomas and 1 large cell carcinoma examined. Because TM is identical to fetomodulin, which modulates embryogenesis, the authors have concluded that TM is an oncodevelopmental antigen. The authors have also suggested that functionally active TM on lung cancer cells may modulate cancer cell behaviors in such ways as exhibiting anticoagulant activity.

Adenocarcinoma↗
PubMed1993

[Acute aneurysm surgery and the Glasgow Coma Scale: relationship with 6-month outcome].

A series of 610 patients who had aneurysm surgery within 7 days of the hemorrhage were analyzed as to the relationship between the preoperative Glasgow Coma Scale (GCS) score and the outcome assessed by using the Glasgow Outcome Scale (GOS) at 6 months after surgery. The patient distribution in accordance with the GCS scores in descending order from 15 to 3 was as follows: 265, 109, 44, 24, 17, 20, 25, 15, 18, 12, 16, 23, and 22 cases, respectively. In general, the larger the GCS score, the better the outcome. Thus, the overall results proved to be significantly correlated with the GCS score prior to surgery (r = 0.608, P < 0.01). As for demarcation levels along the GCS axis in terms of the GOS, a significant difference in the outcome was observed at the level of GCS scores between 15 and 14 (P < 0.0001, Wilcoxon test). However, no borderlines were evident at any GCS levels other than 15/14. The problems of applying the GCS to the grading system of aneurysmal subarachnoid hemorrhage are discussed.

Adult↗
PubMed1993

[Vasospasm and its outcome after early surgery for ruptured cerebral aneurysms: changing pattern of its incidence and outcome during this 9-year period].

The occurrence and outcome of vasospasm (VS) were analyzed in 240 patients who had aneurysm surgery within 7 days of a hemorrhage during 9-year period (1981-89). Occurrence of VS was evaluated by the appearance of ischemic symptoms, (A) with or (B) without CT evidence of infarcts. The surgical outcome was assessed by the Glasgow Outcome Scale 6 months postoperatively. The results in the first and the latter halves of the period were compared. The overall incidence of VS (A+B) was 34.8% (A: 23.5%, B: 11.3%) and 33.6% (A: 15.2%, B: 18.4%) in the first and the latter halves, respectively. Thus, VS leading to infarction showed a tendency to decrease in the latter half of the period, though the overall incidence of VS itself was almost identical in both the first and second halves of the period. The results were also analyzed according to preoperative grading based on the Glasgow Coma Scale (GCS). The tendency toward decreased severity of VS in the latter term was most remarkable in patients with GCS total scores between 14 and 13. The decreased incidence of severe VS proved to be reflected in decreased mortality and in increased rate of good outcome in the latter half of the period. In order to confirm whether the results obtained in our clinic are universal, we applied the same analysis for control groups in four cooperative double-blind clinical trials performed during this period in Japan. The study again showed that the rate of infarction has decreased significantly over the decade, resulting in the improved surgical outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Infarction↗
PubMed1993

[Vasospasm and its outcome after early surgery for ruptured cerebral aneurysms: relationship with the clinical grade based on the Glasgow Coma Scale].

Over a 9 year period, 270 patients who had early aneurysm surgery within 7 days after subarachnoid hemorrhage were analyzed regarding occurrence of vasospasm (VS) and its outcome. Occurrence of VS was recognized by ischemic neurological deterioration, with or without CT evidence of infarcts. Surgical outcome was assessed by the Glasgow Outcome Scale 6 months postoperatively. The results were correlated with age, aneurysm site, day of surgery, and preoperative clinical grade evaluated by the Glasgow Coma Scale (GCS). Thirty patients with the GCS sum score of less than 6 were excluded from the analysis of VS. Eighty two patients (34%) developed VS, of which 36 patients (15%) showed ischemic symptoms only, and 46 (19%) had infarct on CT. The incidence of symptomatic VS was 12% in GCS 15 group (117 patients), 23% in GCS 14-13 group (70 patients), and 11% in GCS 12-7 group (53 patients). That of VS with infarct was 14%, 23%, and 26% in GCS 15, GCS 14-13, and GCS 12-7 groups, respectively. Thus, there was a close correlation between the clinical grade based on the GCS and the incidence of VS, especially with infarct. The grade was also useful in predicting the surgical outcome. VS was more common in the older age group. The site of aneurysm or the day of surgery had no apparent influences on the incidence of VS or its outcome. Overall, the incidence of poor outcome due to VS proved to be 12%, which accounted for one-third of the cases in which there was poor outcome due to various causes.

Adult↗
PubMed1992

Constitutional translocation t(4;22) (q12;q12.2) associated with neurofibromatosis type 2.

We report on a female patient with bilateral acoustic neurinomas and other tumors in the central nervous system (neurofibromatosis type 2: NF2) and the constitutional translocation, t(4;22) (q12;q12.2). The precise identification of the translocation breakpoint (q12.2) on chromosome 22 implies the refined localization of a gene responsible for NF2, and would provide a clue to its molecular characterization and to the isolation of the gene. Chromosomes of a paraspinal neurinoma from the patient were also analyzed, and the same karyotype as seen in cultured peripheral lymphocytes was found. The patient's father was also a carrier of the translocation, but he had no clinical symptoms of NF2, nor did other relatives. Several explanations are offered for the different expression of the translocation between the patient and her father.

Adult↗
PubMed1992

Antisera to calreticulin inhibits sperm motility in mice.

Mouse sperm were rapidly immobilized when exposed to rabbit antisera against rat calreticulin. The inhibition of sperm motility was concentration dependent at dilutions 1:50-350. The velocity of sperm did not change significantly as long as they were motile. Neither motility nor velocity of sperm was affected by adding sheep antisera to bovine calmodulin. The antisera to calreticulin also inhibited in vitro fertilization of mouse eggs. Using the avidin-biotin-peroxidase complex method, the antigen was found to be localized in the acrosome of sperm. The results indicate that calreticulin is present in the acrosome of mouse sperm and may play an important role in sperm motility.

Animals↗
PubMed1992

Cardiac metastasis of lung cancer. A study of metastatic pathways and clinical manifestations.

BACKGROUND: Although lung cancer frequently spreads to the heart, details of cardiac metastases of lung cancer have not been fully discussed. The authors attempted to elucidate the relationship between the mechanisms of cardiac metastasis and a variety of clinical manifestations caused by cardiac metastasis. METHODS: Clinical and autopsy records were reviewed in 74 autopsied cases of lung cancer. In cases with cardiac metastasis, the metastatic pathways to the heart were determined by the macroscopic examinations, and the relationship between the metastatic pathways and the clinical manifestations were studied. RESULTS: Metastases to the pericardium or heart were seen in 23 cases (31%). A lymphatic metastatic pathway was detected in 18 cases (hilar lymphatic routing in 12 cases, and mediastinal lymphatic routing in 6 cases), and a hematogenous metastatic pathway was detected in 5 cases. Malignant pericardial effusion was documented in 15 of 23 cases. The metastatic pathway in 14 of 15 cases was lymphatic (hilar lymphatic routing in 10 cases, and mediastinal lymphatic routing in 4 cases). Patients showing lymphatic metastasis had higher incidence of malignant pericardial effusion than those with hematogenous metastasis (P less than 0.05). Of 23 cases of cardiac metastasis, myocardial infarction was found in 1 case, resulting from the compression of the coronary arteries by the tumor. Concurrent supraventricular arrhythmias were recorded in eight cases with cardiac metastasis. Patients with cardiac metastasis had higher incidence of arrhythmia than those without cardiac metastasis (P less than 0.05). In cases of cardiac metastasis, patients with arrhythmia were older (P less than 0.01) than those without arrhythmia. CONCLUSIONS: The authors concluded that the hilar lymphatic pathway is essential for early development of malignant pericardial effusion in lung cancer and that aging and cardiac metastasis may be responsible for arrhythmia in patients with lung cancer.

Age Factors↗
PubMed1992

Fetal liver T cell receptor gamma/delta+ T cells as cytotoxic T lymphocytes specific for maternal alloantigens.

We have established fetal liver-derived T cell receptor (TCR) gamma/delta+, CD3+ T cell lines that are cytotoxic for maternal T cells. Fetal liver-derived lymphoid progenitors yielded predominantly TCR-gamma/delta+ cell clusters when cultured on fetal bone marrow-derived stromal cells in the presence of a cytokine cocktail under magnetic force. These tightly adherent clusters were cloned by limiting dilution and the resulting cell lines analyzed for phenotype and function. Six of eight TCR-gamma/delta lines from 8-9.5-wk gestation fetuses were V delta 2+ as compared with zero of eight lines from later stages of gestation (10 and 15 wk), where all the lines were V delta 1+. In cytotoxicity assays, these TCR-gamma/delta+, CD3+, CD4-, and CD8+ or CD8- long-term cultured lymphoid cells (LLC) were killer cells active against the class I antigens on maternal T cells. Of the cell lines, the CD8+ TCR-gamma/delta+ LLC had the highest levels of killer activity. Thus fetal liver TCR-gamma/delta+ T cells may play a crucial role in protection against invading maternal T cells generated in the feto-maternal interaction.

Cells, Cultured↗
PubMed1992

Diversity of immunodominant 56-kDa type-specific antigen (TSA) of Rickettsia tsutsugamushi. Sequence and comparative analyses of the genes encoding TSA homologues from four antigenic variants.

There are several antigenic variants in Rickettsia tsutsugamushi, and a type-specific antigen (TSA) of 56-kilodaltons located on the rickettsial surface is responsible for the variation. The primary structures of the protein in two variants, Gilliam and Karp, have been reported independently by us and Stover et al. by cloning and sequencing the corresponding genes (Ohashi, N., Nashimoto, H., Ikeda, H., and Tamura, A. (1990) Gene (Amst.) 91, 119-122; Stover, C. K., Marana, D. P., Carter, J. M., Roe, B. A., Mardis, E., and Oaks, E. V. (1990) Infect. Immun. 58, 2076-2084). In the present study, genes encoding the TSA homologues of the other four variants, Kato, Kawasaki, Kuroki, and Shimokoshi, which are all distinguishable serologically, were cloned and sequenced, and consequently, it became possible to compare the primary structures of the six antigenic variants. The sequence analyses revealed a complete open reading frame encoding 55,308-56,745-dalton proteins with 521-532 amino acids, in which a putative signal peptide consisting of 22 amino acids was recognized at the NH2-terminal end. Transcription of the gene is regulated by several tandem promoters. All TSA molecules have the characteristics of transmembrane proteins with alternating hydrophobic and hydrophilic regions, and contain four variable domains with spans of 16-40 amino acids which are located in the hydrophilic regions in the molecule and show different amino acid sequences among the strains. Phylogenetic classification among the R. tsutsugamushi strains based on TSA homologues supports the antigenic relationships known in the closely and distantly related strains.

Amino Acid Sequence↗
PubMed1992

Quantitative evaluation of water content in a solid protein by deuterium NMR.

A method for evaluating absolute water content in a solid protein based on deuterium NMR measurements in solution is described. By dissolving the hydrated solid protein, which has been specifically deuterium-labeled, into deuterium-depleted water and by comparing the deuterium NMR signal intensity of water (1H2HO) with that of the protein, the amount of water contained in the solid protein is evaluated quantitatively. The method requires a heat pretreatment of the protein sample in water of an enriched (e.g. 2%) deuterium composition for complete hydrogen exchange of the labile protons, and hence is applicable to a protein with a reasonably good reversibility of thermal unfolding. By utilizing this method, the absolute content of the bound water in a protein, Streptomyces subtilisin inhibitor (SSI), lyophilized for 8 h was determined to be 9.2%. The extent of hydration of solid SSI during its exposure to a deuterium-enriched water vapor could also be followed from the deuterium NMR signals in solution. In addition, solid state deuterium NMR measurements of SSI suggested that direct measurement of the natural abundance deuterium signal can give a reasonable estimate of the water content in a solid protein.

Bacterial Proteins↗
PubMed1992

Pathological features of the pulmonary artery in Takayasu arteritis.

Little attention has been paid to the pathological features of the pulmonary artery in Takayasu arteritis. Autopsy specimens of 6 cases of this disease were studied. Lesions were found in the aortic arch and its brachiocephalic branches in all cases and in both the aortic arch and thoracoabdominal aorta in 5 cases. The pathohistologic characters of the pulmonary artery were very similar to those of the systemic artery. Stenosis-recanalization, so-called blood vessels-in-blood vessels, of the pulmonary elastic arteries were found in four cases. These lesions were not observed in the systemic arteries, and most of the newly formed channels in them seemed to be branches of bronchial arteries. Luminal obstruction of pulmonary muscular arteries was observed in 4 cases, cellular arteritis of muscular arteries in 2 cases, and angiomatoid dilatation of small blood vessels in 2 cases. Thus in this study we found peculiar stenosis-recanalization lesions of the pulmonary elastic arteries, and also showed that the pulmonary elastic and muscular arteries are frequently involved in Takayasu arteritis. These findings suggest that pulmonary hypertension could influence morbidity and long-term mortality in this disease.

Adult↗
PubMed1992

Influence of right ventricular ischemia on septal Q waves determined by coronary angioplasty.

The aim of this study is to evaluate the influence of right ventricular ischemia on the amplitude of septal Q waves. Twenty-two patients without previous myocardial infarction who underwent isolated right coronary artery angioplasty were studied. The criterion for right ventricular ischemia was defined as ST elevation of 0.1 mV or more in lead V4R during angioplasty. The patients were divided into two groups: those with (group A, n = 12) and those without (group B, n = 10) right ventricular ischemia. There was no significant difference in the amplitude of septal Q waves in any lead before angioplasty between the two groups. During angioplasty, group A showed a reduction in the amplitude of septal Q waves in leads V5 and V6 but no change in the amplitude of septal Q waves in leads I and aVL. Group B had no significant reduction in the amplitude of septal Q waves in any lead. During angioplasty group A had a higher incidence of reduction of at least 0.05 mV of the septal Q wave amplitude in any lead (58% vs 10%). These results indicate that the amplitude of septal Q waves is occasionally reduced by right coronary occlusion and most such cases are accompanied by right ventricular ischemia. Therefore reduction of the amplitude of septal Q waves during right coronary occlusion appears to be caused by reduction of the electrical force derived from the right ventricular myocardium.

Angioplasty, Balloon, Coronary↗
PubMed1992

Disturbance of membrane function preceding ischemic delayed neuronal death in the gerbil hippocampus.

Slice preparations were made from the hippocampus of gerbils after 5 min of ischemia by carotid artery occlusion and the membrane properties of pyramidal neurons were examined. A majority of CA1 neurons lost the capacity for long-term potentiation following tetanic stimulation of the input fibers. CA3 pyramidal neurons, in contrast, preserved responses similar to those in the normal gerbil. Following ischemia, CA1 pyramidal neurons showed increased spontaneous firing that was highly voltage dependent and was blocked by intracellular injection of the Ca2+ chelator, EGTA. Thirty-five percent of CA1 neurons showed an abnormal slow oscillation of the membrane potential after 24 h following ischemia. Intracellular injection of GTP gamma S or IP3 produced facilitation of the oscillations followed by irreversible depolarization. Our results indicate that ischemia-damaged CA1 neurons suffer from abnormal Ca2+ homeostasis, involving IP3-induced liberation of Ca2+ from internal stores.

Animals↗
PubMed1992

Changes of superoxide dismutase activity and ascorbic acid in focal cerebral ischaemia in rats.

Free radical reactions are supposed to cause ischaemic brain damage, and active oxygens can initiate these chains reaction. If active oxygens play important roles in ischaemic brain damage, the activity of superoxide dismutase, scavenger of superoxide anion, is supposed to decrease in ischaemic brain. The reduced form of ascorbic acid also scavenges superoxide anion. In rat middle cerebral artery focal ischaemia, we investigated the changes in superoxide dismutase activity and the concentration of reduced ascorbate up to 48 hours. Middle cerebral artery territory of each cerebral hemisphere was homogenized. The supernatant was divided into two aliquots; one was dialysed to remove ascorbate and the other was not. The enzyme activity of the dialysed specimen from the ischaemic hemisphere did not decrease within 4 h after the arterial occlusion. The activity of the dialysed specimen from the nonischaemic side remained unchanged during the examination. Reduced ascorbate levels in nondialysed samples showed similar changes to the superoxide dismutase activities in the dialysed samples. Our data suggest that ascorbic acid may exert the enzyme activity and that the enzyme activity remains at the normal level in the early phase of ischaemia despite the irreversible ischaemic changes that take place within 4 h after the onset of ischaemia.

Animals↗
PubMed1992

Change of xanthine dehydrogenase and xanthine oxidase activities in rat brain following complete ischaemia.

We studied the activities of xanthine dehydrogenase and xanthine oxidase in rat forebrain after complete ischaemia. Complete ischaemia was induced by decapitation after transcardiac infusion with saline. The activities of xanthine dehydrogenase and xanthine oxidase immediately after ischaemia were 93.3 +/- 38.7 and 18.8 +/- 7.7 microU/mg protein, respectively, and at 24 h after ischaemia were 183.5 +/- 75.1 and 60.8 +/- 15.2 microU/mg protein, respectively. The ratios of xanthine dehydrogenase/xanthine oxidase immediately and 24 h after ischaemia were 5.04 +/- 1.03 and 3.04 +/- 0.99, respectively. These data indicate that xanthine dehydrogenase and xanthine oxidase activities were maintained even 24 h after complete ischaemia. Conversion of xanthine dehydrogenase to xanthine oxidase proceeds slowly during complete ischaemia.

Animals↗
PubMed1992

Purification and localization of a calcium-binding protein in human spermatozoa.

The purpose of this study was to purify a calcium-binding protein (CalBP) from human spermatozoa of 226 men and to determine the localization of this protein in spermatozoa. The sperm cells were extracted with 0.6 M KCl, and the KCl extract was then subjected to gel filtration and high performance liquid chromatography. Two CalBPs of Mr = 38 kDa and 52 kDa were found by 45Ca(2+)-binding on blotted proteins. Only a 52 kDa CalBP (CalBP-52) was purified to a final yield of 0.007%. The isoelectric point of this protein was 5.1. The human CalBP-52 reacted with rabbit antiserum directed against rat 52 kDa CalBP. An immunocytochemical study showed that this protein was localized on the sperm head. It is postulated that this protein may have important functions related to Ca(2+)-transport into sperm cells.

Animals↗
PubMed1992

Wegener's granulomatosis. Associated with diffuse pulmonary hemorrhage.

The authors report a case of Wegener's granulomatosis with the unusual manifestation of diffuse pulmonary hemorrhage. A 58-year-old man complained of bloody sputum and fever. Chest X-ray films showed multiple nodular shadows in both lung fields. He was diagnosed as having Wegener's granulomatosis by transbronchial lung biopsy, which revealed necrotizing granulomatous inflammation with necrotizing vasculitis. Despite treatment with cyclophosphamide and prednisolone, his condition rapidly deteriorated. An extensive diffuse alveolar shadow appeared in both lung fields in chest X-ray films, anemia became worse, and he died of respiratory failure. Autopsy revealed diffuse alveolar hemorrhage with necrotizing capillaritis in addition to the typical pathological findings in Wegener's granulomatosis. The capillaritis was characterized by neutrophilic infiltration of alveolar septa, and fibrin thrombi in alveolar capillaries. Diffuse pulmonary hemorrhage is uncommon in Wegener's granulomatosis. However, once diffuse pulmonary hemorrhage occurs, the respiratory condition rapidly deteriorates and is life-threatening. Therefore, accurate diagnosis and appropriate treatment are required.

Granulomatosis with Polyangiitis↗