Biomedical subjects

A Kobayashi

Publications and source records attributed to A Kobayashi.

At least 271 records · Page 15Linked to original sources

PubMed1996

Cooperative interaction between AhR.Arnt and Sp1 for the drug-inducible expression of CYP1A1 gene.

Expression of CYP1A1 gene is regulated in a substrate-inducible manner through at least two kinds of regulatory DNA elements in addition to the TATA sequence, XRE (xenobiotic responsive element), and BTE (basic transcription element), a GC box sequence. The trans-acting factor on the XRE is a heterodimer consisting of arylhydrocarbon receptor (AhR) and AhR nuclear translocator (Arnt), while Sp1 acts as a regulatory factor on the BTE. We have investigated how these factors interact with one another to induce expression of the CYP1A1 gene. Both in vivo transfection assays using Drosophila Schneider line 2 (SL2) cells, which is devoid of endogenous Sp1, AhR, and Arnt, and in vitro transcription assays using baculovirus-expressed AhR, Arnt, and Sp1 proteins revealed that these factors enhanced synergistically expression of the reporter genes driven by a model CYP1A1 promoter, consisting of four repeated XRE sequences and a BTE sequence, in agreement with previous observation (Yanagida, A., Sogawa, K., Yasumoto, K., and Fujii-Kuriyama, Y. (1990) Mol. Cell. Biol. 10, 1470-1475). We have proved by coimmunoprecipitation assays and DNase I footprinting that both AhR and Arnt interact with the zinc finger domain of Sp1 via their basic HLH/PAS domains. When either the AhR.Arnt heterodimer of Sp1 was bound to its cognate DNA element, DNA binding of the second factor was facilitated. Survey of DNA sequences in the promoter region shows that the XRE and GC box elements are commonly found in the genes whose expressions are induced by polycyclic aromatic hydrocarbons, suggesting that the two regulatory DNA elements and their cognate trans-acting factors constitute a common mechanism for induction of a group of drug-metabolizing enzymes.

Animals↗

PubMed1996

Difference in adhesion and proliferation of fibroblast between Langmuir-Blodgett films and cast surfaces of poly (gamma-benzyL L-glutamate)/poly(ethylene oxide) diblock copolymer.

Block copolymers consisting of poly (gamma-benzyl L-glutamate) and poly (ethylene oxide) as the hydrophobic and hydrophilic components, respectively were prepared. Cell attachment onto the surfaces of block copolymers fabricated either as well-defined ordered Langmuir-Blodgett (LB) films or solvent cast microphase-separated structures was studied. On ordered LB surfaces, adherent fibroblasts were larger than on the microphase-separated cast surfaces within 15 min. The difference in cell adhesion between LB films and cast surfaces increased with increasing PEO contents in block copolymer. Adherent cells increased with an increase in surface pressure of LB films in any polymer. Phase-contrast microphotographs of adherent cells showed rapid and extensive morphologic changes associated with the LB surface as compared to cast film surfaces. The number of cells grown on the LB surface is greater than that on the cast film.

3T3 Cells↗

PubMed1996

Bone formation and bone resorption in failed total joint arthroplasties: histomorphometric analysis with histochemical and immunohistochemical technique.

To elucidate the reactions of bone around aseptically loosened total joint arthroplasties, 24 interface tissues with adjacent bone were obtained in 17 revision operations (11 hips and six knees). The morphology of the bone surface next to the interface membrane was investigated with histochemical and immunohistochemical techniques and then histomorphometrically analysed. One-third of the total bone surface. 32.69 +/- 5.16% (mean +/- SE) (n = 24), showed positive alkaline phosphatase activity. The bone surface in contact with the cells positive for CD11b (a macrophage marker) amounted to 19.33 +/- 5.16% (n = 24). The proportion of the osteoclastic bone resorption estimated by vitronectin receptor expression was 7.67 +/- 1.82% (n = 21). Tissues retrieved from the sites where radiographic evidence of osteolysis was present (n = 12) had a significantly larger extent of the bone surface in contact with CD11b-positive cells than did the tissues from areas without osteolysis (n = 12, p = 0.0067, Mann-Whitney U test), whereas no significant difference was observed in the extent of osteoclastic bone resorption. These data demonstrate that active bone formation, regarded as a repair process, is the most common feature even in revised cases. They also highlight the role played by macrophages, not as cells producing inflammatory mediators that could activate osteoclasts, but as cells primarily responsible for the bone loss in osteolytic lesions.

Adult↗

PubMed1996

A malignant granular cell tumor of the stomach: report of a case.

We report herein what to our knowledge is the first documented case of a malignant granular cell tumor of the stomach. A 64-year-old woman was admitted to our hospital for investigation of gastric submucosal tumor. Endoscopy disclosed a large hemispherical mass located on the lesser curvature at the gastric antrum with a normal mucosal surface, and computed tomography (CT) revealed a solid tumor about 7 cm in diameter with clear margins. A laparotomy was carried out under the preoperative diagnosis of leiomyosarcoma of the stomach. A tumor was found in the gastric antrum, with extragastric extension to the hepatic hilum, and a distal partial gastrectomy was performed. However, a follow-up CT scan performed 21 months postoperatively revealed a solid tumor of about 10 cm in diameter with clear margins, situated between the liver and the transverse colon. This was subsequently diagnosed as local recurrence and a resection was carried out. Microscopic examination of both the first and second specimens showed that the tumor cells were large and polygonal, with medullary proliferation and finely granular eosinophilic cytoplasm. Mitotic figures were also present. Thus, the lesion was diagnosed as a malignant granular cell tumor of the stomach from the clinical and pathological findings.

Cell Division↗

PubMed1996

Thyroid cancer detected by ultrasound-guided fine-needle aspiration biopsy.

A greater percentage of thyroid cancers can be detected by ultrasound-guided fine-needle aspiration biopsy (UG-FNAB) than by ordinary FNAB. A group of 678 patients were selected sequentially as having been diagnosed with benign nodules by the conventional FNAB method. We reexamined these patients by UG-FNAB and investigated the types of thyroid cancer that were missed by the conventional FNAB. Of the 678 patients diagnosed with benign nodules (using conventional FNAB), 571 (84.2%) demonstrated the same diagnosis when UG-FNAB was used. The remaining 107 patients (15.8%) studied were suspected of having a malignancy after UG-FNAB had been performed. Surgical specimen histology proved thyroid cancer in 99 of the 107 patients: 93 had papillary carcinoma, 4 had follicular carcinoma, 1 had medullary carcinoma and 1 had anaplastic carcinoma. Two drawbacks were noted when conventional FNAB was used: (1) cancer lesions difficult to palpate (n = 55) (e.g., small cancers with or without benign lesions or cancers associated with Hashimoto's thyroiditis or Graves' disease); and (2) palpable cancers with insufficient cell material for analysis (n = 44) (e.g., cystic carcinoma and cancers with calcified lesions. UG-FNAB is a powerful technique for detecting microcancers, cystic carcinomas, cancers associated with benign nodules, Hashimoto's thyroiditis, or coarse calcifications.

Adenocarcinoma, Follicular↗

PubMed1996

Effect of the cholesterol content of a formula on the lipid compositions of plasma lipoproteins and red blood cell membranes in early infancy.

We investigated whether or not a regular formula for full-term infants supplemented with cholesterol (cholesterol-fortified) would increase the plasma cholesterol concentration and alter the red blood cell (RBC) membrane lipid composition in healthy full-term infants compared with their breast-fed counterparts. At 1 mo of age, total plasma cholesterol and low-density-lipoprotein (LDL) cholesterol were significantly higher in the breast-fed infants than in the cholesterol-unfortified, formula-fed infants. At 3 mo of age, total cholesterol and LDL cholesterol were significantly higher in the breast-fed infants than in the two formula-fed infant groups. These significant differences had disappeared by 6 mo of age. Although the cholesterol-unfortified, formula-fed infants had lower proportions of docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3) in the RBC membranes compared with the breast-fed group at 6 mo, DHA and EPA concentrations in the cholesterol-fortified, formula-fed infants were not significantly different. The results of the present study suggest that the plasma cholesterol concentration and fatty acid pattern of the RBC membranes in infants fed a cholesterol-fortified formula may be much closer to those in breast-fed infants than in infants fed a cholesterol-unfortified formula.

Aging↗

PubMed1996

Purification and characterization of the DNA-binding domain of BTEB, a GC box-binding transcription factor, expressed in Escherichia coli.

BTEB is a GC-binding protein that regulates the transcription of genes with a single GC-box or tandemly repeated GC-boxes in the promoter. The DNA-binding domain of BTEB consists of three contiguous Cys2-His2 zinc finger motifs and short segments adjacent to their N- and C-terminal sides [Kobayashi et al. (1995) J. Biochem. 117, 91-95]. The truncated BTEB (residues 120 to 244) containing the DNA-binding domain was expressed in Escherichia coli and purified to homogeneity under denaturing conditions. DNA-binding activity of the BTEB was regenerated by refolding in the presence of Zn2+. The efficiency in regeneration was 70 +/- 10%, and the dissociation constant (Kd) of the DNA-complex was 4 +/- 2 nM. Co2+ also regenerated the DNA-binding affinity of BTEB, albeit with less efficiency than Zn2+. Co-BTEB showed a slightly lower affinity to the specific DNA than Zn-BTEB. Refolding in the presence of Cd2+ resulted in an extremely low efficiency in regeneration of the DNA-binding activity. Zn-BTEB is in a monomer state at concentrations lower than 0.5 microM, and forms a dimer in the concentration range of about 10 to 200 microM.

Amino Acid Sequence↗

PubMed1996

Two mitochondrial 3-hydroxyacyl-CoA dehydrogenases in bovine liver.

3-Hydroxyacyl-CoA dehydrogenase catalyzes the third reaction of fatty acid beta-oxidation spiral. There are three enzymes catalyzing the 3-hydroxyacyl-CoA dehydrogenase, mitochondrial enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase trifunctional protein, and peroxisomal enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase CoA dehydrogenase was not known. In the present study, two monofunctional mitochondrial 3-hydroxyacyl-CoA dehydrogenases were purified from bovine liver. Type I enzyme was composed of two identical subunits with molecular mass of 35 kDa, and type II enzyme was a homotetramer of a 28 kDa polypeptide. In respect to the molecular structures, immunochemical properties, and carbon chain length specificities of acyl-CoA substrates, type I enzyme was the same as the well-known classical enzyme purified from various tissues, but type II enzyme was concluded to be a new enzyme. Type I enzyme was ubiquitous, but type II enzyme was rich in bovine and sheep, of several animal livers so far examined.

3-Hydroxyacyl CoA Dehydrogenases↗

PubMed1996

Purification and properties of human D-3-hydroxyacyl-CoA dehydratase: medium-chain enoyl-CoA hydratase is D-3-hydroxyacyl-CoA dehydratase.

Human medium-chain enoyl-CoA hydratase was purified from liver, because we noticed the presence of a high medium-chain enoyl-CoA hydratase activity in human skin fibroblasts catalyzed by an enzyme different from the known enzymes catalyzing the enoyl-CoA hydratase reaction. Two enzyme preparations were obtained. One of them, preparation I, consisted of 46-kDa polypeptide, and its molecular mass was estimated to be 86 kDa. The other, preparation II, consisted of a major 77-kDa polypeptide and minor smaller polypeptides including 46-kDa polypeptide. The molecular mass of preparation II was 154 kDa. Both enzyme preparations catalyzed reversible dehydration of medium-chain D-3-hydroxyacyl-CoA to 2-trans-enoyl-CoA, but did not react with L-3-hydroxyacyl-CoA. Catalytic properties and immunochemical reactivities of these enzyme preparations were nearly the same. The cross-reactive material to the antibody was confirmed to be in peroxisomes by immunohistochemical study of cultured human skin fibroblasts.

Cells, Cultured↗

PubMed1996

Coupling of Metabolism and Bioconversion: Microbial Esterification of Citronellol with Acetyl Coenzyme A Produced via Metabolism of Glucose in an Interface Bioreactor.

Microbial esterification of citronellol with acetyl coenzyme A (acetyl-CoA) produced via metabolism of glucose was performed with Hansenula saturnus IFO 0809 in an interface bioreactor by using a hydrophilic carrier (an agar plate or an agar-coated filter pad) and a hydrophobic organic solvent (decane). An increase in the glucose concentration on an agar plate led to a decrease in oxidation of citronellol and an increase in the amount of citronellyl acetate. Fed-batch addition of citronellol efficiently alleviated substrate toxicity and resulted in the accumulation of high levels of citronellyl acetate. Furthermore, triple coupling of acetyl-CoA formation, microbial reduction of citronellal to citronellol, and esterification of the resulting citronellol with acetyl-CoA was also an efficient way to prepare citronellyl acetate. By using coupling systems, citronellyl acetate could be efficiently produced without any acetyl donor.

Journal Article↗

PubMed1996

Brugia malayi infection in mice with selective suppression of IgE production.

For the purpose of evaluating the roles of IgE in helminth infections in vivo, IgE-suppressed mice provide useful models. After infection with 50 third-stage larvae of the filarial parasite Brugia malayi, total IgE in BALB/c mice increased to five times higher than uninfected levels. However, anti-B. malayi IgE antibody was not detected, indicating polyclonal IgE B cell activation by the infection. In BALB/c mice which had received repeated injections of anti-mouse epsilon monoclonal antibody from birth and which were subsequently infected, total IgE levels were less than 10 ng/ml, but anti-B. malayi IgG antibody and total IgA were produced similar to the control. Therefore, IgE-isotype-specific suppression was attained. Concerning the protection against B. malayi, the numbers of fourth-stage larvae and adult worms at 2 and 5 weeks after primary infection, respectively, and fourth-stage larvae at 2 weeks after secondary infection were not significantly different between control and IgE-suppressed mice.

Animals↗

PubMed1996

Effect of ligand orientation on hepatocyte attachment onto the poly(N-p-vinylbenzyl-o-beta-D-galactopyranosyl-D-gluconamide) as a model ligand of asialoglycoprotein.

The orientation effect of galactose ligand on hepatocyte attachment was investigated. Poly(N-p-vinylbenzyl-o-beta-D-galactopyranosyl-D-gluconamide )(PVLA), a beta-galactose-carrying styrene homopolymer, was used as a model ligand for the asialoglycoprotein receptors on hepatocytes. PVLA was transferred onto the poly(gamma-benzyl L-glutamate) (PBLG) or PBLG/poly(ethylene glycol) (PEG)PBLG Langmuir-Blodgett (LB) films as the monolayer level. The dichroic fluorescence values of the confocal microscope indicated that the PVLA transferred onto the LB films was located with a preferential orientation of its molecular axes with regard to the direction of the alpha-helix of polypeptide. Hepatocyte recognized well-oriented galactose moieties of the surface of PVLA through asialoglycoprotein receptors.

Animals↗

PubMed1996

Identification of the nuclear localization signal of mouse DNA primase: nuclear transport of p46 subunit is facilitated by interaction with p54 subunit.

DNA polymerase alpha-primase is a replication enzyme necessary for DNA replication in all eukaryotes. Mouse DNA primase is composed of two subunits: a 46 kDa protein (p46), which is the catalytic subunit capable of RNA primer synthesis, and a 54 kDa protein (p54), whose physiological role is not clear. To understand the structure-function relationship of DNA primase, we set out to characterize these two subunits individually or in combination using a cDNA expression system in mammalian cultured cells, and determined the subcellular distribution of ectopically expressed DNA primase. The p54 expressed in COS-1 cells after transfection was predominantly localized in the nucleus, whereas p46 was retained in the cytoplasm as shown by indirect immunofluorescence analysis. Using several mutant proteins with deletions or substitutions as well as chimeric constructs, we identified the nuclear localization signal of p54 as RIRKKLR, encoded near the amino terminus (residues 6-12). Furthermore, co-expression of both p46 and p54 subunits markedly altered the subcellular distribution of p46; co-expressed p46 was transported into the nucleus as efficiently as p54. These results demonstrate that p54 has a nuclear localization signal and is able to be translocated into the nucleus independently of DNA polymerase alpha subunits. In contrast, p46 lacks a nuclear localization signal, and its nuclear translocation is facilitated by interaction with p54. We present here first evidence for a novel role of p54 in the nuclear translocation process, and a piggy-back binding transport mechanism of mouse DNA primase.

3T3 Cells↗

PubMed1996

Angiographic and coronary risk factor analyses of Japanese patients with ischemic heart disease before age 40--a multicenter cooperative study.

Coronary angiographic and risk factor (RF) characteristics were analyzed in 133 Japanese patients with ischemic heart disease (IHD) who were less than 40 years old and who had undergone coronary angiography (CAG) during the past 10 years at six university hospitals in the Tokyo area. We compared the coronary angiographic characteristics of the subject group with those of 216 controls with coronary sclerosis detected by CAG who were more than 40 years old (older control group) and the RF characteristics with those of 133 sex- and age-matched volunteers (younger control group). Sixty seven percent of the subjects (89 cases) were diagnosed as having myocardial infarction (MI) and 33% (44 cases) had angina pectoris (AP). Coronary artery disorders in this group consisted of 103 (77%) cases of coronary sclerosis, 20 (15%) cases of coronary spasm and 10 (8%) cases of miscellaneous diseases, eg, possible vasculitis with connective tissue disease, congenital anomalies, etc. The incidences of significant (> or = 75%) sclerotic narrowing in 0 vessels (31%) and 1 vessel (49%) in the subject group were significantly (p < 0.01) higher than those in the older control group, while the incidence of multivessel disease was significantly (p < 0.05) less in the subject group than in the older control group. The incidences of the following coronary risk factors were significantly (p < 0.05) higher in the subjects than in the younger controls: smoking (83% vs 35%), hypercholesteremia (44% vs 10%), obesity (31% vs 9%), hypertension (29% vs 3%), familial IHD (28% vs 7%) and diabetes mellitus (19% vs 2%). Thus, zero- or single-vessel disease predominated in the younger subject group and the prevalence of coronary risk factors was significantly higher in the subject.

Adult↗

PubMed1996

Geranyl 6-O-alpha-L-arabinopyranosyl-beta-D-glucopyranoside isolated as an aroma precursor from leaves of a green tea cultivar.

A new glycosidic aroma precursor was isolated from green tea leaves (Camellia sinensis var. sinensis cv. Yabukita) along with the known primeverosides of cis-linalool 3,6-oxide, linalool and geraniol. These glycosides were separated by chromatographic isolation on Amberlite XAD-2, ODS flash chromatography, and finally HPLC. The chemical structure of the new unknown glycoside was confirmed as geranyl 6-O-alpha-L-arabinopyranosyl-beta-D-glucopyranoside (geranyl beta-vicianoside) by spectrometric analyses and by an enzymatic hydrolysis with glycosidase followed by GC-MS and HPLC analyses. Moreover the vicianoside was hydrolyzed with acetone powder obtained from fresh tea leaves to generate the same compounds, suggesting this glycoside to be a tea aroma precursor.

Acyclic Monoterpenes↗

PubMed1996

Immunohistochemical analysis of the endocrine cells in the pancreatic islets of cattle.

The distribution of endocrine cells and the areas of islets in the bovine pancreas were investigated by immunohistochemical methods. The islets in the A-region, which consisted of the left lobe, the ventral portion of the body, and the ventral and distal portions of the right lobe, contained a central core of insulin-containing (B-) cells surrounded by glucagon containing (A-) cells, a few somatostatin-containing (D-) cells and sporadic pancreatic polypeptide-containing (PP-) cells. The islets in the B-region, which consisted of the uncinate process, and the dorsal and proximal portions of the body and the right lobe, contained a central mass of B-cells, and peripheral cells which were predominantly PP-cells with a few D-cells but no A-cells. The areas of islets in the B-region were small as compared with those in the A-region. From these findings it is suggested that A- and PP-cells have a complementary relationship to one another. In view of this hypothesis, two types of islet, A-cell-rich and PP-cell-rich islets, were identified. The A-region contained A-cell-rich islets derived from the dorsal pancreatic primordium, while the B-region contained PP-cell-rich islets that originated from the ventral primordium. In the bovine pancreas, the areas containing PP-cell-rich islets are greater than those in previously examined species.

Animals↗

PubMed1996

[Influences of orthognathic surgery to facial skin sensation--an analysis with a new testing method].

This study introduces an original testing method on facial skin sensation and describes the results obtained by its application to patients after orthognathic surgery. The alterations of skin sensation in lower lip and chin area were examined in 135 patients who had undergone orthognathic surgery, by application of electrical stimulation through an original pencil shaped probe. Detection threshold of the same area before surgery were used as control, and the location and size of the area with thresholds higher than control levels were measured. The control thresholds ranged from 0.13 mA to 0.21 mA. The higher threshold area was found in 86.3% of all the patients in 1 month after surgery, in 27.7% after 1 year. The threshold levels declined with the time, and in none of the patients the threshold level was higher than 1.0 mA more than 2 years after surgery. The patients whose threshold level was more than 1.0 mA in 1 month postoperatively showed a tendency to have the area with a threshold higher than the control level even 1 year later (p < 0.0001). The threshold of the younger patients tended to improve smoothly than the older. In addition, the patients with a shorter set-back or advance distance had a slighter sensory disturbance and recovered more smoothly than those with a longer distance.

Adolescent↗

PubMed1996

[Mobile right atrial thrombus: a case report of surgical removal].

A 71-year-old man was admitted due to brain infarction. An abnormal floating mass was found in the right atrium by echocardiography. The mass was assumed to be a thrombus. The patient was failed to be in danger of pulmonary embolism, so it was decided to remove surgically. The thrombus was removed under cardiopulmonary bypass including the atrial wall where it was attached, because it was difficult to rule out the possibility of cardiac tumor macroscopically. The tumor showed pathological findings of thrombus. Postoperative course was uneventful.

Aged↗