Biomedical subjects

A Tanaka

Publications and source records attributed to A Tanaka.

At least 127 records · Page 7Linked to original sources

PubMed2001

Creation of cell surface-engineered yeast that display different fluorescent proteins in response to the glucose concentration.

We have successfully created a novel yeast strain able to monitor changes in environmental conditions by displaying either green fluorescent protein (GFP) from Aequorea victoria or blue fluorescent protein (BFP), a variant of GFP, on its cell surface as a visible reporter. For the display of these fluorescent proteins on the cell surface of Saccharomyces cerevisiase, our cell-surface-engineering system was utilized. The GAPDH promoter, which is active in the presence of glucose, and the UPR-ICL promoter from Candida tropicalis, which starts to function in the presence of a reduced level of glucose, were employed simultaneously to express the GFP-encoding gene and the BFP-encoding gene, respectively. This cell-surface-engineered yeast strain emitted green fluorescence from the cell surface when sufficient glucose was present in the medium, and blue fluorescence from the same cell surface when the glucose in the medium was consumed. The fluorescent proteins displayed on the cell surface using the different promoters enabled us to monitor the concentrations of intra- and/or extracellular glucose that regulated activation or inactivation of the promoters. This novel yeast strain could facilitate the computerized control of various bioprocesses measuring emitted fluorescence.

Genetic Engineering↗

PubMed2001

Development of novel whole-cell immunoadsorbents by yeast surface display of the IgG-binding domain.

The ZZ domain derived from Staphylococcus aureus, which binds to the Fc part of immunoglobulin G (IgG), was displayed on the cell surfaces of yeast Saccharomyces cerevisiae by cell-surface engineering using the C-terminal half of alpha-agglutinin under control of the 5'-upstream region of the isocitrate lyase gene from Candida tropicalis (UPR-ICL). Display of ZZ on the cell surface was confirmed by immunofluorescence microscopy. Enzyme-linked immunosorbent assay (ELISA) and sandwich ELISA using the S. cerevisiae cells displaying ZZ detected IgG and antigen (human serum albumin) down to a concentration of 1-10 ng/ml in both cases. The detection range covered by these assay systems was wide and could be varied by adjusting the amount of cells and reaction times with horseradish peroxidase (HRP) substrate. Moreover, yeast cells displaying ZZ were successfully used for repeated affinity purification of IgG from serum. These results indicate that S. cerevisiae displaying ZZ may constitute novel and genetically renewable whole-cell immunoadsorbents widely applicable to immunoassays and affinity purification.

Animals↗

PubMed2001

Cell surface-engineered yeast displaying a histidine oligopeptide (hexa-His) has enhanced adsorption of and tolerance to heavy metal ions.

A histidine oligopeptide (hexa-His) with the ability to chelate divalent heavy metal ions was displayed on the yeast cell surface for the purpose of enhanced adsorption of heavy metal ions. We genetically fused a hexa-His-encoding gene with the gene encoding the C-terminal half of alpha-agglutinin that includes a glycosylphosphatidylinositol anchor attachment signal sequence and attached the hexa-His peptide on the cell wall of Saccharomyces cerevisiae. This surface-engineered yeast adsorbed three to eight times more copper ions than the parent strain and was more resistant to copper (4 mM) than the parent (below 1 mM at pH 7.8). It was possible to recover about a half of the copper ions adsorbed by whole cells with EDTA treatment without disintegrating the cells. Thus, we succeeded in constructing a novel yeast cell with both tolerance to toxic contaminants and enhanced adsorption of metal ions onto the cell surface.

Adsorption↗

PubMed2001

AoHapB, AoHapC and AoHapE, subunits of the Aspergillus oryzae CCAAT-binding complex, are functionally interchangeable with the corresponding subunits in Aspergillus nidulans.

Two genes, AohapB and AohapE, encoding subunits of the Aspergillus oryzae CCAAT-binding complex were cloned and sequenced. The polypeptides encoded by AohapB and AohapE were expressed in Escherichia coli and used to reconstitute a DNA-binding complex with recombinant AoHapC. The DNA-binding activity was observed only in the presence of all three subunits, indicating that AoHapB, AoHapE and AoHapC are essential for CCAAT-binding. Furthermore, introduction of the AohapB, AohapC and AohapE genes into the A. nidulans hapB delta, hapC delta and hapE delta strains, respectively, revealed that the A. oryzae Hap subunits are functionally interchangeable with the corresponding subunits in A. nidulans.

Amino Acid Sequence↗

PubMed2001

Effect of fractionated exposure to carbon ions on the frequency of chromosome aberrations in tobacco root cells.

The induction of chromosome aberrations in tobacco root tip cells was measured after exposure to either 18 MeV/n carbon ions or 2 MeV electrons. The RBE value for acute exposure was found to be about 10. Splitting the dose into two fractions did not produce any significant effect on the yield of aberrations following carbon-ion exposure, whereas a clear decrease was observed after exposure to electrons thereby indicating an induction/activation of error-free repair after the first fraction. Moreover, this decrease appeared to be independent of the types of chromosome aberrations. On the other hand, it was suggested that the lack of any significant effect on the yield of aberrations is either due to a lack of error-free repair or to a less efficient damage repair after exposure to carbon ions.

Carbon↗

PubMed2001

Predominant expression of fibroblast growth factor (FGF) 8, FGF4, and FGF receptor 1 in nonseminomatous and highly proliferative components of testicular germ cell tumors.

Nonseminomatous components within testicular germ cell tumors affect patient prognosis to varying degrees. These components are well known to mimic early embryonic totipotential tissues. Prompted by the recent observation that fibroblast growth factor (FGF) 8, FGF4, and FGF receptor (FGFR) 1 are required for the growth of early postimplantational embryonic tissues, we investigated the expressions of FGF8, FGF4, and FGFRI in surgically resected specimens of primary testicular germ cell tumors using an immunohistochemical method. All cases of embryonal carcinoma (14 cases), yolk sac tumor (3 cases), and choriocarcinoma (3 cases) showed positive immunostaining for FGF8, FGF4, and FGFR1. In contrast, out of 13 cases of seminoma, immunostaining was negative for FGF8, FGF4, and FGFR1 in 8 cases (61.5%), 6 cases (46.1%), and 7 cases (53.8%), respectively. In 7 cases of mature and immature teratoma, most areas showed negative immunostaining. In addition, the Ki-67 labeling index showed extremely high mitogenic activity in embryonal carcinoma, yolk sac tumor, and choriocarcinoma, which are precisely the carcinomas with the highest expressions of FGF8, FGF4, and FGFR1. It is in keeping with the immunohistochemical result that murine teratocarcinoma P19 cells were shown to express FGF8, FGF4, and FGFRI only under undifferentiated growth conditions. Taken together, these findings confirm the involvement of FGF8, FGF4, and FGFR1 in highly proliferative conditions of nonseminomatous germ cell tumors.

Adolescent↗

PubMed2001

Extreme discrepancy between macroscopic diagnosis and pathological findings of gallbladder cancer treated by hepatopancreatoduodenectomy.

Diagnosis of gallbladder cancer in terms of invasion depth and spread is an important factor in determining cumulative survival after surgical treatment. However, diagnostic methods available at present occasionally fail to judge staging correctly. We report a case of gallbladder cancer which showed extreme discrepancy between the preoperative macroscopic and imaging diagnosis (positive direct invasion to the liver and invasion to the bile duct and duodenum through the serosal layer; S3, Hinf3, Binf2, and stage IV by the Japanese Society of Biliary Surgery classification) and the pathological findings (limited in vasion within the subserosal layer; ss, hinf0. binf0, and stage II). This discrepancy allowed us to perform curative treatment by hepatopancreatoduodenectomy, including extended right lobectomy of the liver, external bile duct resection, resection of the mesocolon, and lymph node dissection. Surgeons should aim for curability of advanced gallbladder cancer by radical resection until accurate methods for the preoperative diagnosis of cancer spread are available, because the clinical picture may be modified by inflammatory changes.

Cholangiopancreatography, Endoscopic Retrograde↗

PubMed2001

Surgical management of a graftenteric fistula: a modified method of in situ reconstruction.

Between December 1989 and May 1998, we performed a modified method of in situ reconstruction on three of seven patients with graftenteric fistulas (GEFs) at the Kurume University Hospital. The modification involved performing an anastomosis of the infrarenal abdominal aorta and running a new prosthesis through the left side of the descending colon in the retroperitoneal cavity, and wrapping the proximal anastomosis and the proximal site of the prosthesis in the greater omentum. Good results were achieved in all three patients. We describe herein this modified method of in situ reconstruction for a GEF and summarize the case reports of these three patients.

Adult↗

PubMed2001

Treatment of ruptured hepatocellular carcinoma.

BACKGROUND: The problem of whether surgical or conservative treatment is indicated for ruptured hepatocellular carcinoma (HCC) has not been analyzed from the viewpoint of long-term development of hepatitis viral infection from liver fibrosis to liver cirrhosis. Although transcatheter arterial embolization (TAE) for hemostasis followed by two-stage hepatectomy has been established as the best treatment for ruptured HCC, there still remain difficulties in the treatment of some patients. METHODS: Twelve patients with ruptured HCC who were surgically or conservatively treated were retrospectively analyzed in terms of modality of treatment, liver function, extension of HCC, complications, survival rate, and cause of death. RESULTS: Tumor rupture can occur either in the early phase or in the terminal phase during the development from liver fibrosis to liver cirrhosis, while tumor rupture occurs at the advanced stage in terms of HCC extension. TAE for emergent hemostasis or prevention of re-bleeding was performed in ten patients, while TAE was contraindicated in one patient and emergent laparotomy for hemostasis was performed in one patient. In four patients, elective extended surgical resection was performed, because liver function was evaluated as clinical stage 1 according to the General rules for the clinical and pathological study of primary liver cancer of the Liver Cancer Study Group of Japan. In seven patients, conservative or medical treatment was selected, because liver function was evaluated as poor. The surgically treated group, who could tolerate extensive operation, survived longer than the conservatively treated group. CONCLUSIONS: While TAE remains the best method to employ for hemostasis, it still has limitations. Hence, we should be mindful of other possible modalities for hemostasis and their outcomes. Rupture of HCC at an early phase in the development of liver fibrosis is a good indication for elective surgical treatment and should be distinguished from rupture in the terminal phase of liver cirrhosis, which should be treated conservatively. Although elective surgical treatment can be performed in selected patients, tumor size and location of HCC, in addition to liver function, should be taken into consideration.

Aged↗

PubMed2001

Cardiac fibroblasts are major production and target cells of adrenomedullin in the heart in vitro.

OBJECTIVE: Adrenomedullin (AM) is a potent vasodilator peptide. Plasma AM concentration is increased in patients with various heart diseases, and both myocytes (MCs) and non-myocytes (NMCs) secrete AM and express its receptors. These facts suggest that cardiac cells possess an autocrine/paracrine capability mediated by AM. METHODS: MCs and NMCs were prepared from cardiac ventricles of neonatal rats. AM and endothelin-1 concentrations were measured by radioimmunoassays, and interleukin-6 level by a specific bioassay. Total nitrite/nitrate contents were measured with a fluorescence assay kit. RESULTS: A basal secretion rate of AM from NMCs was 2.8-fold higher than that from MCs. Interleukin-1beta, tumor necrosis factor-alpha and lipopolysaccharide stimulated AM secretion from NMCs but not from MCs. AM stimulated interleukin-6 production in the presence of these cytokines or lipopolysaccharide, which was more prominent in NMCs. In the presence of interleukin-1beta, AM augmented nitric oxide synthesis 2.7-fold in NMCs, but slightly in MCs. NMCs secreted endothelin-1 at a rate nine times higher than MCs, and AM inhibited endothelin-1 secretion from NMCs. CONCLUSION: This in vitro study suggests that AM in the heart is mainly produced in NMCs and exerts its effects through NMCs, especially under inflammatory conditions.

Adrenomedullin↗

PubMed2001

A double-blind trial on the effects of atorvastatin on glycemic control in Japanese diabetic patients with hypercholesterolemia.

A double-blind, placebo-controlled, parallel-group study was performed to determine whether atorvastatin, a new HMG-CoA reductase inhibitor, could effectively and safely reduce plasma LDL-cholesterol concentrations in Japanese patients with type-2 diabetes without influencing glycemic control. The subjects were patients with hypercholesterolemia (serum cholesterol concentration > or =5.7 mmol/l (220 mg/dl)) and stable glycemic control. The fasting concentrations of hemoglobin A(1C) (HbA(1C)), fructosamine, and 1,5-anhydroglucitol (1,5-AG) were measured as indices of glycemic control. Plasma lipid concentrations and the safety of the drug were also examined. Forty eligible patients in two groups of 20 each were administered atorvastatin (10 mg/day) or placebo. Neither atorvastatin nor placebo caused a significant change in HbA(1C), fructosamine, or 1,5-AG concentrations. Atorvastatin significantly reduced total cholesterol and LDL-cholesterol concentrations from baseline by 29.7% (p<0.0001) and 41.6% (p<0.0001), respectively. The incidence of clinical adverse events and that of abnormal changes in laboratory test values did not differ between the two groups. In this trial, atorvastatin effectively and safely reduced LDL-cholesterol concentrations in diabetic patients with hypercholesterolemia without influencing glycemic control. These findings are clinically important because there are many diabetic patients with hypercholesterolemia and such patients have a high risk of developing arteriosclerotic disease.

Adult↗

PubMed2001

C4d and C4bp deposition along the glomerular capillary walls in a patient with preeclampsia.

Complement (C) 4d and cofactor C4b binding protein (C4bp) are detected in the glomerular capillary walls of a patient with preeclampsia. A 32-year-old nullipara had proteinuria of 1.2 g/d and edema at the 33rd week of pregnancy. Gradually the urinary protein excretion increased, reaching 5.1 g/d at the 37th week. The patient also showed hypertension at this stage. After normal mature delivery, the level of the urinary protein excretion remained at 3 to 4 g/d. Renal biopsy performed by means of light and electron microscopy, 15 days after delivery, showed almost normal glomeruli and modest subendothelial widening. Immunohistochemistry indicated that immunoglobulin (Ig) A, IgG, C1q, C3c, and C4c were not deposited in the glomeruli, whereas weakly positive IgM and fibrin-related antigen (FRA) were observed. Conversely, C4d, C3d, and C4bp were strongly deposited. Protein S (PS) also was observed, with a similar distribution pattern to that of C4bp. Immunoelectron microscopy showed the deposition of C4d along the capillary walls and of C4bp in the subendothelium. These findings suggest that the C4 activation process as well as the regulation process of C system and of the inflammatory coagulation axis by C4bp and PS may play an important role in the pathophysiology of preeclampsia, so-called glomerular capillary endotheliosis (GCE).

Adult↗

PubMed2001

Fluctuations of Emax of the left ventricle: effect of atrial natriuretic polypeptide.

Recently the circadian rhythm of fluctuations in heart rate variability (HRV) has gained increasing attention, and the use of appropriate treatment corresponding to the circadian rhythm has become an important issue. However, the question has been raised as to whether the rhythm of fluctuation is only limited to HRV, and if a rhythm is also present in the contraction of the heart. The mathematical technique of electrical circuit simulation of the cardiovascular system was used to observe the Emax rhythm. In this study, the therapeutic effect of various drugs, including atrial natriuretic polypeptide (ANP), was confirmed. The effect of inotropic drugs including ANP on Emax was observed, and the results based on an old and a new method of determining Emax . were examined. Furthermore, the chaos analysis of Emax was also made. The time series of Emax showed an increased complexity due to the administration of ANP. In conclusion, it might be important to consider not only the fluctuation of HRV, but also an analysis of the fluctuation in the contraction of the heart.

Adrenergic beta-Antagonists↗

PubMed2001

Effects of age and gender on the expression of brain-derived neurotrophic factor mRNA in rat retrosplenial cortex following administration of dizocilpine.

Using in situ hybridization, we studied the effects of age and gender on the expression of brain-derived neurotrophic factor (BDNF) mRNA and heat shock protein hsp-70 mRNA in the rat retrosplenial cortex following administration of the noncompetitive NMDA receptor antagonist (+)-MK-801 (dizocilpine). Male and female Sprague-Dawley rats (5 weeks, 12 weeks, or 10 months old) were given a single intraperitoneal injection of saline (1 ml/kg) or dizocilpine (0.3, 1.0, or 3.0 mg/kg). No expression of BDNF mRNA and hsp-70 mRNA was detected in the rat retrosplenial cortex after administration of saline (1 ml/kg, IP). Administration of dizocilpine (0.3, 1.0, or 3.0 mg/kg, IP) caused a marked induction of BDNF mRNA and hsp-70 mRNA in the retrosplenial cortex of male and female rats, in a dose-dependent manner. Female rats were more sensitive to the induction of BDNF mRNA and hsp-70 mRNA in the retrosplenial cortex by dizocilpine as compared to male rats. It was also found that adult (12 weeks old) and aged (10 months old) rats were more sensitive to the induction of hsp-70 mRNA and BDNF mRNA in the retrosplenial cortex by dizocilpine as compared to young (5 weeks old) rats. These results suggest that the age and gender differences observed in the expression of BDNF mRNA and hsp-70 mRNA in the retrosplenial cortex by dizocilpine may be associated with the differences in dizocilpine-induced neurotoxicity observed with gender and age within the same region.

Aging↗

PubMed2001

Isolation of an androgen-inducible novel lipocalin gene, Arg1, from androgen-dependent mouse mammary Shionogi carcinoma cells.

Here we report isolation of an androgen-regulated novel gene from an androgen-dependent mouse mammary Shionogi carcinoma SC-3 cell line. Using a polymerase chain reaction-based subtraction method and Northern blotting analysis, we isolated four androgen-inducible genes from SC-3 cells. Nucleotide sequencings identified three of the genes as cyclin D1, beta-catenin, and fatty acid synthase, respectively, but the fourth, a gene tentatively named as Arg1 (androgen-regulated gene 1), remained undefined. The cloned 2.0-kb sized Arg1 cDNA encoded 414 amino acid sequences. The deduced amino acid sequences, sharing about 30% homology with cathepsin family members at a protein level, had relatively conserved residues around the three proteinase active sites reported earlier. In Northern blotting, Arg1 mRNA was found in kidney, heart, lung, and to a lesser degree, in spleen and liver. Its transcripts were also detected in male reproductive organs on RT-PCR. In addition, its expression levels in prostate were markedly reduced after castration. Unexpectedly, Arg1-expressing COS1 cells showed no significant proteinase activity to various synthesized substrates under neutral or acidic conditions in this study. This might have been due to the replacement of the cysteinyl active site for proteinase to serine residue in the Arg1 amino acid sequences. Given that Arg1 also contains a lipocaline signature known as a binding motif for small hydrophobic molecules at the center of its amino acid sequences, Arg1 is a lipocalin family gene regulated by androgens in prostate and Shionogi carcinoma cells.

Amino Acid Sequence↗

PubMed2001

Synthesis and antibacterial activity of novel 4-pyrrolidinylthio carbapenems Part IV. 2-Alkyl substituents containing cationic heteroaromatics linked via a C-C bond.

The synthesis and biological activity of a novel series of 2-alkyl-4-pyrrolidinylthio-beta-methylcarbapenems containing a variety of cationic heteroaromatic substituents linked via a C-C bond is described. As a result of these studies, we selected FR21818 (In) as a candidate compound for development. FR21818 exhibited a well balanced spectrum of antibacterial activity, including Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA), excellent urinary recovery, good stability against renal dehydropeptidase-I (DHP-I). no antigenicity and mutagenicity, weak toxicities, and good efficacy and therapeutic effect on mice systemic infections. Affinities to PBP's, permeability of outer membrane, and plasma levels in mice, dog, and cynomolgous monkey of FR21818 are also reported.

Animals↗

PubMed2001

Ethenesulfonamide and ethanesulfonamide derivatives, a novel class of orally active endothelin-A receptor antagonists.

In the previous paper, we described a series of 2-phenylethenesulfonamide derivatives, a novel class of ET(A)-selective endothelin (ET) receptor antagonists, including the 2-methoxyethoxy derivative 2a and the 2-fluoroethoxy derivative (2b). In this paper, we wish to report further details of structure-activity relationships (SARs) of the two regions of the molecule in compound 2b, which were the alkoxy region at the 6-position of the core pyrimidine ring and the 2-phenylethenesulfonamide region. In these modifications, replacement of the 2-fluoroethoxy group with a methoxy group (6e) and replacement of the 2-phenylethenesulfonamide group with a 2-(pyridin-3-yl)ethenesulfonamide group (6l) or 2-phenylethanesulfonamide group (6q) were well tolerated both in the ET(A) binding affinity and ET(A) selectivity. Among them, compound 6e showed further improvement in oral activity compared to 2b. After oral administration, compound 6e inhibited the big ET-1 induced pressor response in conscious rats at 0.3mg /kg with a duration of >6.5h. Compound 6e also exhibited a potent antagonistic activity in the pithed rats.

Administration, Oral↗

PubMed2001

Detection of HPV in Japanese and Chinese oral carcinomas by in situ PCR.

Human papillomavirus (HPV) is established as the cause of almost 100% of cervical carcinomas. However, the association of HPV with oral squamous cell carcinomas (SCCs) is less well understood. We examined the prevalence of HPV in oral SCCs in samples of Japanese and Chinese populations. Using in situ polymerase chain reaction (PCR) analysis (MY09 and MY11 consensus primers), HPV was detected in the nucleus of epithelia and tumor cells in oral lesions. Analysis revealed the specific presence of HPV DNA in all cases of SCC in our Japanese (10/10) and Chinese (10/10) population samples. These results suggest that HPV infection could be one of several risk factors contributing to oral SCC in Japanese and Chinese.

Carcinoma, Squamous Cell↗