Biomedical subjects

K Tamura

Publications and source records attributed to K Tamura.

At least 757 records · Page 42Linked to original sources

PubMed1993

Hypercoagulable state induced by thrombocytapheresis.

The influence of the continuous-flow automated blood cell separator. Fenwal CS-3000, on blood coagulation and the fibrinolytic system in blood donors was studied. Blood samples were taken from the collection line of donors undergoing extracorporeal circulation, before and after platelet pheresis. Of the molecular markers, prothrombin fragment-F1 + 2 (PF1 + 2) markedly increased from 0.8 +/- 0.3 to 2.9 +/- 2.0 nM/ml (P < .004), thrombin antithrombin III complex (TAT) also markedly increased from 2.6 +/- 1.3 to 56.0 +/- 24.0 micrograms/L (P < .001), fibrinopeptide A (FPA) increased slightly from 0.8 +/- 0.9 to 3.8 +/- 4.2 micrograms/L (P < .05), and alpha 2-plasmin inhibitor (alpha 2-PI) decreased slightly from 95 +/- 8 to 91 +/- 9% (P < .05). In one donor with the highest level of PF1 + 2, TAT, FPA, and plasmin inhibitor complex after platelet pheresis, protein C, protein S, C4b-binding protein, ATIII, plasminogen, alpha 2-PI, and coagulation factors were decreased. In blood donors undergoing platelet pheresis using the continuous-flow automated blood cell separator, Fenwal CS-3000, a hypercoagulable state was observed. Changing the materials of the plastic disposables to a more thromboresistant material may prevent the hypercoagulable state in donors induced by platelet pheresis using the blood cell separator.

Adult↗

PubMed1993

Induction of polarizing activity by retinoic acid occurs independently of duplicate formation in developing chick limb buds.

Retinoic acid (RA) is known to mimic the action of the zone of polarizing activity (ZPA) in inducing the formation of anteroposterior duplicates in the chick limb bud. Although RA had been thought to be a morphogen produced by the ZPA, recently we (Noji et al., 1991) and Wanek et al. (1991) independently concluded that RA induces polarizing activity in cells at the anterior margin of the chick limb bud. In this study, we examined the distribution of RA-induced polarizing activity in the limb bud. At first, RA-containing beads were implanted into various regions of stages 20-23 limb buds. After 24 hr, we grafted tissue fragments from sites adjacent to the RA beads into the anterior margin of host limb buds. High polarizing activity was induced in anterior-distal and apical mesoderm regions immediately under the apical ectodermal ridge (AER) when beads presoaked in 1 mg/ml RA were grafted to anterior sites at stages 19-20. However, in mesoderms distant from the AER, even if adjacent to the implanted RA bead, only low activity was induced. Although implantation of beads soaked in a high concentration (10 mg/ml) of RA did not result in duplications but rather in truncations of the limbs, the apical mesodermal cells in these limbs were converted to ZPA cells, indicating that induction of polarizing activity by RA can occur independently of duplicate formation. The ability to respond to RA treatment was rapidly lost in the cells along the anterior margin of stage 22 limb buds. When the anterior AER was removed, the induction of polarizing activity in the anterior margin of limb buds was markedly reduced. Thus, the AER seems to be necessary for the RA-directed induction of polarizing activity.

Animals↗

PubMed1993

MRC-5, human embryonic lung fibroblasts, induce the duplication of the developing chick limb bud.

The anteroposterior (A-P) axis pattern of the chick limb is likely to be controlled by a small region of mesenchyme cells at the posterior margin of the limb bud (ZPA, zone of polarizing activity). In this study, we found that MRC-5 fibroblast cells had the capacity for duplicated-pattern formation of the chick limb along the A-P axis when grafted to the anterior region of the limb bud. MRC-5 cells were effective only during pre-limb bud stages, and the leg bud was more responsive than the wing bud. Grafted cells remained at the base of the limb bud when limb development proceeded. These results suggest that the products of MRC-5 cells are involved in three possible processes of duplicated-pattern formation: induction of the polarizing activity; maintenance of this activity, which is present weakly at pre-limb bud stages; and determination of A-P axis as the ZPA factor(s). By allowing the use of a small number of cells of embryonic tissues with polarizing activity, the analysis of duplicate formation with the MRC-5 cell line provides a powerful tool for elucidating the molecular nature of the ZPA.

3T3 Cells↗

PubMed1993

Expression of the gene encoding a translational elongation factor 3 homolog of Chlorella virus CVK2.

A gene encoding a putative translational elongation factor 3 (EF-3) on the genome of Chlorella virus CVK2 has been cloned and sequenced. It encodes for a predicted polypeptide of 1120 amino acids (aa) with a molecular mass of 127 kDa. The overall amino acid sequence of CVK2 EF-3 (vEF-3) showed 36.1% identity and 83.6% similarity to that of Saccharomyces cerevisiae EF-3. Functional domains including two sets of ATP-binding motifs were extremely well conserved between vEF-3 and yeast EF-3; 63.6% identity and 92.4% similarity in total 330-aa portions. Northern blot analysis indicated that the vEF-3 gene was transcribed in the host cells early, at 20 min postinfection (p.i.), as well as late, 3-4 hr p.i. Western blot analyses with anti-vEF-3 antibody detected the 120 kDa vEF-3 protein product after 40 min p.i. It was present until the final stages of infection but absent in the virion. The vEF-3 gene was highly conserved among all Chlorella viruses isolated in Japan.

Amino Acid Sequence↗

PubMed1993

The relationship between the expression of blood group-related antigens and the cell proliferation of pancreatic carcinomas induced by N-nitrosobis(2-oxopropyl)amine in hamsters.

The relationship between expression of blood group-related antigens (BGRAs) A, B, H, and cell proliferation was investigated during pancreatic carcinogenesis and in transplanted pancreatic carcinomas induced by N-nitrosobis(2-oxopropyl)amine in hamsters. Immunohistochemical staining was performed using monoclonal antibodies (MoAbs) against BGRAs A, B, H, and bromodeoxyuridine (BrdU). The labeling index (LI) was determined as the ratio of the number of BrdU-labeled cells to the total number of cells counted in each lesion. During carcinogenesis, the LI was observed to increase in line with the increase in the extent of atypism (P < 0.01). The mean LIs of the hyperplasia, atypical hyperplasia, and carcinoma were 0.32, 3.21, and 10.2, respectively. The mean LIs of transplanted carcinomas were higher than those of the original carcinomas (P < 0.01). The reactivity with each of the antibodies was determined using an arbitrary scoring system. Staining with MoAbs A and B (staining intensity; 1+ to 3+) appeared to be more intense than that with MoAb H (1+ to 2+) during carcinogenesis. Regarding the growth rate, which was very high, in the transplanted carcinomas, MoAb A reacted with all the cancer cells (4+), whereas, MoAbs B and H reacted with fewer cells (1+ to 3+). These results indicate that the A antigen in particular is associated with the cell proliferation of pancreas, especially with carcinoma induced in hamsters.

ABO Blood-Group System↗

PubMed1993

Heterotopic autotransplantation of the pancreas segment after pylorus-preserving total pancreatectomy: a case report of successful surgical treatment for chronic pancreatitis.

A 38-year-old man who had suffered for 5 years from persistent abdominal pain caused by alcoholic chronic pancreatitis, presented with diffuse calcification of the entire pancreas with cystic formation of the pancreatic head. After a pylorus-preserving total pancreatectomy, the pancreatic head, including the cyst, was removed extracorporeally by bench surgery, and the remaining segment of the body and tail autotransplanted heterotopically to the iliac vessels with a pancreaticojejunostomy. Total resolution of the pain was achieved postoperatively, and dietary intake has been satisfactory. Both endocrine and exocrine pancreatic functions have been well preserved, and no insulin has been needed. Three months after his operation, the patient has returned to leading a normal life.

Adult↗

PubMed1993

Heterotopic autotransplantation of a pancreas segment with enteric drainage after total or subtotal pancreatectomy for chronic pancreatitis.

Four patients with chronic alcoholic pancreatitis and one patient with idiopathic chronic pancreatitis, who had total or subtotal distal pancreatectomies for persistent pain, underwent simultaneous autotransplantation of a pancreas segment to preserve the pancreatic function. The segment was autotransplanted heterotopically to the iliac fossa with anastomosis of the splenic vessels to the iliac vessels to prevent reinnervation, and the pancreatic duct was anastomosed to the intestine to preserve exocrine function. Postoperatively, the patency of the graft vessels was confirmed by angiography in every patient. Complete pain relief has been obtained in all patients with a followup duration of 4-89 mo. Except for one patient who had been treated preoperatively with insulin injections for diabetes, the patients remained normoglycemic without exogenous insulin administration and demonstrated satisfactory insulin secretion during a 75-g oral glucose tolerance test. An exocrine pancreatic diagnostant test using p-aminobenzoic acid yielded nearly similar levels to the preoperative value for all patients. Heterotopic autotransplantation of the pancreas segment appears to be effective for preserving pancreatic function, as well as providing permanent pain relief for patients with chronic pancreatitis who require extensive resection of the pancreas.

Adult↗

PubMed1993

Congenital microgastria in an infant with the VACTERL association.

A patient with microgastria and the VACTERL association is presented. The association of widespread anomalies with microgastria in our patient strongly suggests that such anomalies may all result from mesodermal deficiencies caused by defective migration at the primitive streak stage during the 3rd to 4th week of embryogenesis.

Abnormalities, Multiple↗

PubMed1993

Mechanism of acute deterioration of the neurological status following rapid and massive intraluminal thrombosis in case of a giant intracavernous carotid artery aneurysm: demonstration by MR imaging.

A case is reported of a thrombosed giant aneurysm of the intracavernous carotid artery. Transient neurological deterioration was attributable to the acute swelling of the aneurysmal mass after rapid and massive intraluminal thrombosis. Characteristics on the magnetic resonance imaging of this case are reported and discussed.

Acute Disease↗

PubMed1993

A randomized phase II trial of low-dose aclarubicin vs very low-dose cytosine arabinoside for treatment of myelodysplastic syndromes.

We performed a randomized phase II trial comparing low-dose aclarubicin (LC-ACR) with very low-dose cytosine arabinoside (VLD-AC) in 39 consecutive untreated patients with myelodysplastic syndromes (MDS), including refractory anemia (RA), RA with excess of blasts (RAEB) and RAEB in transformation (RAEB-t). Nineteen patients received the VLD-AC therapy; 2 good responses (GR) and 2 partial responses (PR) were obtained in 11 patients with RAEB and RAEB-t, while 2 PR were obtained in 8 RA patients. Eighteen patients received the LD-ACR therapy; 2 GR and 4 PR were obtained in 11 RAEB/RAEB-t patients while 2 PR in 7 RA patients. There was no significant difference in the therapeutic effects and survival between these two groups of patients. These observations suggest that the LD-ACR therapy is effective in some patients with MDS and can be used as an alternative to the low-dose Ara-C therapy.

Aclarubicin↗

PubMed1993

Functional roles of cyclic guanosine 3',5'-monophosphate analogue in cerebral vasodilation.

1. Vasodilating effects of cyclic nucleotides in cerebral vasculature were examined using membrane permeable cyclic nucleotide analogues, 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP) and 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP). 2. In isolated canine basilar artery (CBA), 8-Br-cGMP but not 8-Br-cAMP, significantly inhibited Ca(2+)-induced and agonist [serotonin(5-HT), prostaglandin(PG)F2 alpha or endothelin]-induced contraction, in a concentration-dependent manner. 3. When Ca2+ was depleted from intracellular store sites by pretreatment with A23187, 8-Br-cGMP but not 8-Br-cAMP strongly attenuated contractions induced by Ca(2+)-influx. 4. Neither 8-Br-cGMP nor 8-Br-cAMP modified contraction induced by caffeine which elicits Ca2+ release from intracellular Ca2+ store. 5. 8-Br-cGMP lowered the high K(+)-induced sustained [Ca2+]i elevation. 6. These results suggest that, at least in CBA, cGMP exerts its inhibitory effect on the contraction induced by influx of Ca2+, by reducing the level of [Ca2+]i and reducing [Ca2+]i sensitivity of the contractile machinery.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1993

Is ST segment re-elevation associated with reperfusion an indicator of marked myocardial damage after thrombolysis?

OBJECTIVES: The significance of ST segment re-elevation at reperfusion by thrombolysis was evaluated. BACKGROUND: The significance of ST re-elevation has not been studied. Hence, we evaluated whether ST re-elevation is an indicator of marked myocardial necrosis after reperfusion. METHODS: Twelve-lead electrocardiograms were recorded serially, before thrombolysis and immediately after each coronary angiographic procedure during thrombolysis. RESULTS: In 32 patients with acute myocardial infarction, 15 showed transient ST re-elevation at reperfusion (group 1) and 17 showed reduction (group 2). Peak creatine kinase (CK) and CK-MB isoenzyme activity levels were significantly higher in group 1 than in group 2. Twelve patients in group 1 had strongly positive findings on early technetium-99m pyrophosphate scintigraphy, compared with one patient in group 2 (p < 0.001). The regional ejection fraction did not increase from the acute phase to the chronic phase in group 1. The ST deviation before thrombolysis was significantly greater in group 1 than in group 2 (p < 0.001). All 14 patients in group 1 showed Thrombolysis in Myocardial Infarction (TIMI) grade 0 flow and 12 of these patients did not have good collateral flow before thrombolysis. CONCLUSIONS: These data suggest that 1) ST re-elevation at reperfusion is a sign of limited myocardial salvage by thrombolysis, and 2) high ST elevation and TIMI grade 0 flow without good collateral flow before thrombolysis may be predictive variables for marked myocardial necrosis after reperfusion.

Aged↗

PubMed1993

Case report: MR imaging of a carcinoid tumour of the liver.

A surgically confirmed solitary primary liver carcinoid tumour is described. MR imaging demonstrated a low signal intensity mass on T1-weighted images, a low signal intensity mass with small area of higher intensity on fat saturation T1-weighted images, and heterogeneous high signal intensity mass on T2-weighted images. The fibrous capsule and septa were demonstrated as low signal intensity bands on both proton- and T2-weighted images.

Carcinoid Tumor↗

PubMed1993

Clinical applications of ICG Finger Monitor in patients with liver disease.

The indocyanine green (ICG) Finger Monitor system is a non-invasive indication of ICG concentrations in the blood. In this study, significant correlation was found between the sensor signal voltage and plasma ICG concentrations ranging from 0.04 mg/dl to 1.0 mg/dl (r = 0.998, P < 0.001) in vivo. The ICG clearance curve showed an initial sharp rise 20-30 s after bolus injection, followed by a small rise. The concentration then deceased exponentially. In 196 patients with chronic liver disease, there was a close correlation between the KICG (plasma disappearance rate) and R15 (blood retention ratio at 15 min) (r = 0.886, P < 0.001, r = 0.912, P < 0.001) and corresponding values calculated by the conventional ICG method. In 263 cases with chronic liver disease, the plasma disappearance rates calculated using this monitor (mean +/- S.D.) were 0.156 +/- 0.064 (n = 20) in the control group, 0.129 +/- 0.060 (n = 92) in the chronic hepatitis group, 0.048 +/- 0.025 (n = 59) in the cirrhosis group and 0.059 +/- 0.03, (n = 92) in the group with hepatocellular carcinoma. A significant difference in the plasma disappearance rate and blood retention ratios 15 min after injection of ICG using this system was observed between control cases and the chronic hepatitis and cirrhosis groups (P < 0.0001). In 36 cases, the time from injection to the appearance of ICG in the fingertip significantly decreased in the cirrhosis group (P < 0.01). The ICG Finger Monitor system was shown to be useful clinically as well as for research due to its accuracy and non-invasive nature.

Adult↗

PubMed1993

Suspension organ culture of the fetal mouse ear.

To observe the development of the fetal ear, we grew the explanted ears of mouse fetuses 13 days old in suspension organ culture on a roller device for 48 hours. We used the BGJb-medium (Fitton-Jackson Modification) supplemented by 25% fetal bovine serum, and added a solution containing penicillin-streptomycin at the rate of 1% to the total volume. It was observed histologically that some explants developed ossicles that corresponded with those of mouse fetuses 15 days old in vivo. Sensory structures in the inner ear developed in organ culture as well. This method may help to resolve the question of ontogenesis of the ossicles.

Animals↗

PubMed1993

Do low-power lasers change phase transition temperature of dipalmitoyl phosphatidylcholine (DPPC) membrane?

This study was designed to investigate the effects of the He-Ne laser (632.8 nm of wavelength, 8.5 mW in power, Senko Med. Co. Ltd., Tokyo, Japan) on the phase transition temperature of dipalmitoyl phosphatidylcholine (DPPC) membranes. Liposomal bilayers of DPPC (12.5 mM) were obtained with ultrasonification for 45 min at 40 degrees C and refrigerated for 2-3 days at 5 degrees C. The bilayers vesicle solution was divided into 3-ml working aliquots, which were assigned to three groups. The aliquots in Group 1 were used as controls without irradiation and the aliquots in Groups 2 and 3 were irradiated in 37 degrees C baths for 15 to 30 min, respectively. To determine phase transition temperature, optical density (%T; percent of permittance) of each aliquot was measured spectrophotomechanically at a wavelength of 440 nm while increasing its temperature at a rate of 0.5 degrees C every minute. Main phase transition temperatures in Groups 1, 2, and 3 were 41.54 +/- 0.23 degrees C (n = 10), 41.50 +/- 0.27 degrees C (n = 10), and 41.30 +/- 0.36 degrees C (n = 10), respectively. No significant difference between the nonirradiation and irradiation groups was established. These results suggest that irradiations of low-power He-Ne lasers up to 30 min do not change important physical characteristics of artificial DPPC membranes.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1993

Effects of oxidative stress induced by redox-enzyme modulation on the progression stage of rat hepatocarcinogenesis.

Effects of oxidative stress induced by redox-enzyme modulation on the progression stage of hepatocarcinogenesis were examined by monitoring both hepatocyte injury and hepatocellular carcinoma development in F344 rats bearing preneoplastic liver nodules induced by the Cayama-Farber procedure. Redox-enzyme modulation, which included increased cytochrome P450 reductase activity induced by phenobarbital-Na (100 mg/kg, i.p. for 3 days), inhibition of DT-diaphorase by dicumarol (25 mg/kg, i.p.), depletion of glutathione by phorone (200 mg/kg, i.p.), supplementation with the Fe(III) sodium salt of EDTA (50 mg/kg, i.p.) and redox-cycling activation by menadione (50 mg/kg, i.g.), exerted no prominent hepatocyte injury within nodules but did cause slight injury in the surrounding hepatocytes in nodule-bearing rats. The same treatments induced severe hepatocyte injury in non-treated normal rats. Redox-enzyme modulation performed every other week for 33 weeks significantly reduced the number of hepatocellular carcinomas developing in nodule-bearing rats. These results indicate that preneoplastic nodules are resistant to the oxidative stress induction caused by redox-enzyme modulation treatment and that, despite toxic effects in surrounding hepatocytes, no progression pressure is exerted. Indeed, the treatment rather demonstrates an inhibitory effect of the evolution of the nodules into hepatocellular carcinomas.

Alanine Transaminase↗

PubMed1993

Estimation of the number of nucleotide substitutions in the control region of mitochondrial DNA in humans and chimpanzees.

Examining the pattern of nucleotide substitution for the control region of mitochondrial DNA (mtDNA) in humans and chimpanzees, we developed a new mathematical method for estimating the number of transitional and transversional substitutions per site, as well as the total number of nucleotide substitutions. In this method, excess transitions, unequal nucleotide frequencies, and variation of substitution rate among different sites are all taken into account. Application of this method to human and chimpanzee data suggested that the transition/transversion ratio for the entire control region was approximately 15 and nearly the same for the two species. The 95% confidence interval of the age of the common ancestral mtDNA was estimated to be 80,000-480,000 years in humans and 0.57-2.72 Myr in common chimpanzees.

Analysis of Variance↗