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Biomedical subjects

K Nagano

Publications and source records attributed to K Nagano.

At least 37 records · Page 2Linked to original sources
PubMed2000

Prostanoids regulate proliferation of vascular smooth muscle cells induced by arginine vasopressin.

The aim of the present study was to investigate the effect of arginine [Arg(8)]vasopressin (vasopressin) on proliferation of vascular smooth muscle cells and the mechanisms underlying the action of vasopressin. To clarify these issues, we used two different types of vascular smooth muscle cells, cultured adult rat aortic smooth muscle cells and A10 cells, a cell line derived from fetal rat aorta. Vasopressin (10(-8) to 10(-6) M) significantly stimulated the proliferation of rat aortic smooth muscle cells in a dose-dependent manner. In contrast, vasopressin significantly inhibited the proliferation of A10 cells. This inhibition was abolished when A10 cells were treated with indomethacin. Vasopressin stimulated the production of prostanoids several-fold in A10 cells but not in rat aortic smooth muscle cells. These effects were completely blocked by the vasopressin V(1) receptor antagonist, 1-¿1-[4-(3-acetylamino-propoxy)benzoyl]4-piperidyl¿-3, 4-dihydro-2(1H)-quinolinone (OPC21268), but not by the vasopressin V(2) receptor antagonist, (+/-)-5-dimethylamino-1-[4-(2-methylbenzoylamino)benzol]-2, 3,4,5-tetrahydro-1H-benzazepine hydrochloride (OPC31260). These results indicate that vasopressin has diverse effect on proliferation of vascular smooth muscle cells through the vasopressin V(1) receptor, depending on the production of growth regulatory prostanoids.

6-Ketoprostaglandin F1 alpha↗
PubMed2000

Clinico-radiological study of total knee arthroplasty after high tibial osteotomy.

The results of total knee arthroplasty (TKA) after high tibial osteotomy (HTO) and problems encountered during the operation were investigated in 23 patients (28 knees). HTO was performed by Coventry's method in 18 knees and by Maquet's method in 10 knees. The mean interval from HTO to TKA was 86 months (range, 3 to 288 months) and the mean follow-up period after TKA was 25 months (range, 6 to 116 months). Radiological evaluation showed that the proximal part of the tibia was shifted and tilted lateroinferiorly after HTO. Thus, a tendency to patella infera was observed. Lateral shift of the proximal part of the tibia was more marked with Maquet's method than with Coventry's method (P < 0.01). Posterior inclination of the tibial articular surface before TKA was smaller in the patients who gained a range of motion of 90 degrees or more after TKA than in those with less than 90 degrees (P < 0.05). In patients with 70 points or more on the three-university score after TKA, there was no change in the joint line level between before and after TKA, while the joint line was significantly lower after TKA in those with less than 70 points (P < 0.01). When TKA is done after HTO, various technical problems may influence the outcome, such as correction of the soft tissue imbalance, in addition to difficulties with patellar eversion and exposure of the proximal part of the tibia. The clinical results of TKA after HTO tend to be slightly inferior to those of primary TKA, probably because of such technical problems.

Aged↗
PubMed2000

Massive bleeding from a gastric erosion after transcatheter arterial chemoembolization for hepatocellular carcinoma in a patient with mild haemophilia A.

We observed massive bleeding from a gastric erosion following transcatheter arterial chemoembolization (TAE) in a patient with mild haemophilia A. A 78-year-old haemophiliac (factor VIII level over 60%) received TAE with farmorubicin and spongel. Haematemesis and melena with loss of consciousness occurred 3 days [corrected] after TAE, and endoscopy revealed superficial erosions with oozing. Toxic effects of the anticancer drug in conjunction with the bleeding disorder may have caused the massive bleeding. We should always consider the possibility of unexpected complications in patients with bleeding disorders; gastrointestinal bleeding can develop during treatment for liver tumours.

Aged↗
PubMed2000

Growth factor-induced promoter activation of murine phospholipase C delta4 gene.

Phospholipase C delta4 (PLCdelta4) is one of the delta-type PLC isozymes, the expression of which is induced in nuclei by treatment with serum and also in some cancer cells. We isolated and analyzed a promoter region of the murine PLCdelta4 gene. DNA sequence analysis showed that this region is GC-rich and has no TATA box, and the region from -143 to -127 was found, by luciferase activity and gel mobility-shift assay, to be essential for transcription of PLCdelta4. We also found that the promoter activity of PLCdelta4 was stimulated by treatment with growth factors such as bradykinin, lysophosphatidic acid, and Ca2+ ionophore in addition to serum. In parallel, we detected PLCdelta4 mRNA induction and an increase in complex formation of the promoter region and nuclear protein from HeLa cells on stimulation with these growth factors. Finally, we found that trapping the growth factor-induced cytoplasmic Ca2+-inhibited activation of the promoter activity and protein induction in nuclei. These results show that PLCdelta4 may have an important role in nuclei in response to growth factors, and its expression may be partially regulated by an increase in cytoplasmic Ca2+.

Animals↗
PubMed2000

[Anesthetic management in a patient with severe acute pancreatitis during pregnancy].

Continuous epidural anesthesia was used in a 34 year-old pregnant woman with acute pancreatitis related to hypertriglyceridemia. She underwent an emergency cesarean section due to severe pancreatitis under spinal anesthesia. After delivery, extended incision was made to examine the pancreas and to perform drainage. Epidural infusion using 1% mepivacaine and buprenorphine was started to reduce pain and improve microcirculation. After starting epidural infusion with other therapies, clinical feature and data improved. This case suggests that reduction of severe pain and improvement of microcirculation are important in therapies of severe pancreatitis.

Acute Disease↗
PubMed2000

[Anesthetic management for a patient with autoimmune hemolytic anemia].

A 69-year-old woman with autoimmune hemolytic anemia (AIHA) received gastric resection and splenectomy under general anesthesia combined with epidural anesthesia. Her blood type had been determined as type A, Rh type CCDee, with anti-e-antibody and anti-pdl-antibody positive as autoantibodies. We applied the technique of hemodilutional autologous transfusion to supplement the blood loss during the operation to prevent hemolysis or occurrence of new antibody after homologous transfusion. We should pay much attention to a patient with AIHA to find signs of peri-operative hemolysis and to give the treatment for hemolysis in early stage. We consider that the hemodilutional autologous transfusion is a useful technique for the anesthetic management of the patient having a rare blood type.

Aged↗
PubMed1999

Immunohistochemical determination of the Wilson Copper-transporting P-type ATPase in the brain tissues of the rat.

Immunohistochemical localization of Copper-transporting P-type ATPase (ATP7B), a gene product responsible for Wilson disease, was visualized in the brain tissues of the Long-Evans agouti rat in detail using tissue-blotting technique and confocal laser microscopy. The ATP7B was intensely detected in neuronal cells of the hippocampal formation, olfactory bulbs, cerebellum, cerebral cortex and nuclei in the brainstem in which high amounts of copper and cuproenzymes, dopamine beta hydroxylase and Cu,Zn-superoxide dismutase (Cu,Zn-SOD) were detected. The present results suggest that ATP7B plays key roles in neurotransmissions of catecholamine pathway and preventing brain tissues from injury by superoxide radicals to regulate the cellular Cu concentration and/or activities of cuproenzymes related to neurotransmissions and a free radical metabolism. Furthermore, it is reasonable to assume that neurotoxicity due to abnormal copper accumulation or irregular regulation of cuproenzymes in the critical brain regions by mutation of the ATP7B gene leads to neurological failures of Wilson disease.

Adenosine Triphosphatases↗
PubMed1999

A novel phospholipase C delta4 (PLCdelta4) splice variant as a negative regulator of PLC.

It has been reported that there are two alternatively spliced variants of phospholipase C-delta4 (PLCdelta4), termed ALT I and II, that contain an additional 32 and 14 amino acids in their respective sequences in the linker region between the catalytic X and Y domains (Lee, S. B., and Rhee, S. G. (1996) J. Biol. Chem. 271, 25-31). We report here the isolation and characterization of a novel alternative splicing isoform of PLCdelta4, termed ALT III, as a negative regulator of PLC. In ALT III, alternative splicing occurred in the catalytic X domain, i.e. 63 amino acids (residues 424-486) containing the C-terminal of the X domain and linker region were substituted for 32 amino acids corresponding to the insert sequence of ALT I. Although the expression level of ALT III was found to be much lower in most tissues and cells compared with that of PLCdelta4, it was significantly higher in some neural cells, such as NIE-115 cells and p19 cells differentiated to neural cells by retinoic acid. Interestingly, recombinant ALT III protein did not retain enzymatic activity, and the activity of PLCdelta4 overexpressed in COS7 cells was markedly decreased by the co-expression of ALT III but not by ALT I or II. Moreover, N-terminal pleckstrin homology domain (PH domain) of ALT III alone could inhibit the increase of inositol-1,4, 5-trisphosphate levels in PLCdelta4-overexpressing NIH3T3 cells, whereas a PH domain deletion mutant could not, indicating that the PH domain is necessary and sufficient for its inhibitory effect. The ALT III PH domain specifically bound to phosphatidylinositol (PtdIns)-4,5-P2 and PtdIns-3,4,5-P3 but not PtdIns, PtdIns-4-P, or inositol phosphates, and the mutant R36G, which retained only weak affinity for PtdIns-4,5-P2, could not inhibit the activity of PLCdelta4. These results indicate that PtdIns-4,5-P2 binding to PH domain is essential for the inhibitory effect of ALT III. ALT III also inhibited PLCdelta1 activity and partially suppressed PLCgamma1 activity, but not PLCbeta1 in vitro; it did inhibit all types of isozymes tested in vivo. Taken together, our results indicate that ALT III is a negative regulator of PLC that is most effective against the PLC delta-type isozymes, and its PH domain is essential for its function.

3T3 Cells↗
PubMed1999

Effect of noble metal conditioners on bonding between prosthetic composite material and silver-palladium-copper-gold alloy.

STATEMENT OF PROBLEM: Mechanical retentive devices and the application of complicated surface preparation have been indispensable for bonding composite material to the metal substructure of restorations. PURPOSE: This study evaluated the priming effects of 4 metal conditioners on bonding between a prosthetic veneering material and a silver-palladium-based casting alloy. MATERIAL AND METHODS: Four primers designed for conditioning noble metal alloys (Alloy Primer, Metaltite, Metal Primer II, and V-Primer) were assessed (all materials contain organic sulfur compounds). Cast disk specimens made of silver-palladium-copper-gold alloy (Castwell M.C.12) were primed with 1 of the 4 primers, and bonded with a light-activated prosthetic composite material (Axis). Shear testing was performed before and after thermocycling for evaluation of bond durability. RESULTS: All primed groups showed improved 24-hour bond strengths compared with the unprimed group. After thermocycling, 3 groups primed with the Metal Primer II, Alloy Primer, and Metaltite agents exhibited the highest bond strength. CONCLUSION: Use of 1-liquid metal conditioners containing sulfur compounds was a simple and useful method for improving bonding between the alloy and the composite material tested.

Composite Resins↗
PubMed1999

Reactive lymphoid hyperplasia of liver coexisting with chronic thyroiditis: radiographical characteristics of the disorder.

BACKGROUND: Reactive lymphoid hyperplasia of the liver is an extremely rare entity, with six cases reported so far. METHODS: We encountered a 47-year-old Japanese female with reactive lymphoid hyperplasia of the liver, which coexisted with chronic thyroiditis. The lesion was discovered incidentally as a hypo-echoic mass with a hyper-echoic rim at a routine ultrasonography examination. It increased from 12 to 17 mm diameter in 6 months. Radiological studies, such as contrast-enhanced computerized tomography (CT) and angiography demonstrated a hypervascular lesion. RESULTS: It was consequently diagnosed as a neoplasm with malignant potentiality and she underwent partial hepatectomy. The lesion was composed of small mature lymphocytes which formed prominent lymphoid follicles with germinal centres, scattered plasma cells and stromal fibrosis. Immunohistochemical study revealed polyclonal origins of the involved lymphocytes. DNA analysis for the immunoglobulin heavy gene and the T cell receptor beta gene using Southern blot hybridization showed no monoclonality. The following features have characterized the images in past cases, as well as ours: hypo-echoic mass, occasionally with a rim, in ultrasonography and hypervascularity, shown by angiography and enhanced CT.

Angiography↗
PubMed1999

Patent ductus venosus.

BACKGROUND: Patent ductus venosus is extremely rare with only 14 cases reported in the world literature. We present a case of patent ductus venosus. METHODS AND RESULTS: A 29-year-old male was admitted with melaena stool caused by gastric haemorrhagic ulcers. Laboratory data disclosed severe anaemia; however, liver function tests were normal. Serum ammonia was also within the normal range. Serological viral markers for hepatitis B or C were all negative. The abdominal ultrasonography and computed tomography indicated a 12 mm diameter shunt located in the left lobe of the liver, which connected the portal vein with the left hepatic vein. After treatment for gastric ulcers, percutaneous transhepatic portography was performed and an enormous shunt connecting the umbilical portion of the portal vein with the left hepatic vein was revealed. CONCLUSIONS: Histological findings of the liver biopsy showed that portal venules could not be observed in the portal areas and that no fibrosis or inflammatory cell infiltration were shown. Because of the anatomical position of the shunt, the case was diagnosed as patent ductus venosus.

Adult↗
PubMed1999

Low risk of TT virus (TTV) infection in medical workers.

The rate of infection with TT virus (TTV), a novel single-strand DNA virus was evaluated and the clinical and laboratory features in affected Japanese medical workers were analysed. TTV DNA was measured in 356 medical workers and in 150 age-matched controls using a seminested polymerase chain reaction. TTV DNA was detected in 62 of 356 medical workers (17.4%). There were no differences in the prevalence of TTV infection between medical workers and controls (18.9%) and in the characteristics of medical workers with TTV infection and medical workers without it, except that the mean age of patients with TTV infection was higher than that of patients without TTV. The medical workers were drawn from three groups: medical doctors, nurses and clinical laboratory technicians. There was no statistically significant difference between the rate of TTV infection in the three groups. These findings suggest that the risk of TTV infection in medical workers is low and not related to liver dysfunction.

Adult↗
PubMed1999

Difference in target organs in carcinogenesis with a heterocyclic amine, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, in different strains of mice.

2-Amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) induces cancers in the forestomach and liver, but not in the colon, of CDF1 male and female mice, which are thought to be resistant to induction of colon cancer by 1,2-dimethylhydrazine. In this study, we examined the carcinogenicity of MeIQ in C57BL/6N female mice, which are susceptible to 1,2-dimethylhydrazine. This strain of mice developed carcinomas of the cecum, colon and liver, but not the forestomach, when given a diet containing 300 ppm of MeIQ. This fact indicates that the target organs of a chemical carcinogen change depending on the strain of a given animal species.

1,2-Dimethylhydrazine↗
PubMed1999

fcsA29 mutation is an allele of polA gene of Escherichia coli.

The cold-sensitive fcsA29 mutation of Escherichia coli was found to be a new type of cold-sensitive allele of the polA gene encoding DNA polymerase I, caused by an Asp(116)-->Asn change in the 5'-->3' exonuclease domain. The fcsA29 mutant showed typical polA mutant phenotypes such as UV sensitivity and unacceptability of recA mutation. Cold-sensitive growth of the mutant was suppressed by introduction of a sulA mutation, indicating that cell filamentation was due to the SOS response.

Alleles↗
PubMed1999

Development of resistance to chloroform toxicity in male BDF1 mice exposed to a stepwise increase in chloroform concentration.

To investigate the development of resistance to chloroform toxicity, a 4-week inhalation study was conducted in which BDF1 male mice were exposed to a low level of chloroform for an initial two-week period, and thereafter the exposure concentration was increased for a second two-week period. The animals were exposed to inhalation of chloroform vapor 6 hr per day, 5 days per week, with clinical observation and measurement of body weight conducted. These results demonstrate that pre-exposure to chloroform at a low dose level induced resistance to a higher dose of chloroform in male mice. This resistance was dependent on the pre-exposure concentration.

Animals↗
PubMed1999

[A case of Ramsay Hunt syndrome associated with local meningitis, multiple cranial neuropathy, and the second cervical nerve involvement].

A 76-year-old man with herpetic vesicle in the right auricle developed ipsilateral 5th, 6th, 7th, and 8th cranial nerves involvement and pain in the dermatome of the second cervical nerve. The CSF study revealed elevated opening pressure up to 220 mmH2O, and pleocytosis up to 151 cells/mm3. Ninety-nine percent of the CSF cells were mononuclear cells. CSF protein was 47 mg/dl, and CSF glucose was 62 mg/dl. On the 24th hospital day the CSF cells decreased to 13/mm3 with 100% mononuclear cells. Titer of varicella-zoster virus (VZV) antibody was significantly elevated in CSF. Brain MRI and ABR demonstrated no abnormality. Although disorders of 5th and 6th cranial nerves and second cervical nerve improved, mild facial nerve palsy lasted and hearing disturbance showed no recovery. There are only seven cases of Ramsay Hunt syndrome associated with external ophthalmoplegia in the literature. However, un like the present case, none of these cases presented disorders of upper cervical nerves. In this case, we speculate that spreading of reactivated VZV caused local meningitis and multiple cranial nerve involvement as well as the second cervical nerve.

Abducens Nerve↗