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Biomedical subjects

Y Yamada

Publications and source records attributed to Y Yamada.

At least 415 records · Page 23Linked to original sources
PubMed2000

Successful treatment of large malignant tumor involving the skull base by radiosurgery combined with intraarterial chemotherapy and embolization.

Stereotactic radiosurgery can be used to treat malignant tumors involving the skull base. While it avoids extensive sacrifice of the normal structures surrounding the tumor, radiosurgery does not eradicate the tumor mass immediately. We present a patient with a large hypervascular malignant tumor involving the skull base that resulted in intracranial hypertension. He was successfully treated with stereotactic radiosurgery combined with intra-arterial chemotherapy and embolization of the arteries feeding the tumor. We discuss radiosurgery, chemotherapy, embolization and other therapeutic modalities for treating large malignant tumors involving the skull base.

Aged↗
PubMed2000

Serum markers of graft-versus-host disease after bone marrow transplantation.

BACKGROUND: Graft-versus-host disease is one of the major complications after allogenic bone marrow transplantation, but it is not easy to anticipate the onset. OBJECTIVES: The purpose of this study was to determine clinically useful markers of acute graft-versus-host disease. METHODS: We measured the serum levels of tumor necrosis factor-alpha, soluble tumor necrosis factor receptor 1, soluble c-kit, soluble Fas, soluble intercellular adhesion molecule-1, growth-related oncogene protein-alpha, thrombomodurin, and interleukin-16 in 13 patients at 1 to 7 weeks after allogenic bone marrow transplantation. RESULTS: The patients with acute graft-versus-host disease showed a significant increase of tumor necrosis factor, soluble tumor necrosis factor receptor 1, soluble Fas, soluble intercellular adhesion molecule-1, and growth-related oncogene protein-alpha, although there was a decrease of soluble c-kit. The increases of serum soluble tumor necrosis factor receptor 1, intercellular adhesion molecule-1, and growth-related oncogene protein-alpha were preceded by the elevation of soluble Fas. CONCLUSION: The patients with acute graft-versus-host disease had increased serum levels of tumor necrosis factor-alpha, soluble tumor necrosis factor receptor 1, soluble Fas, and soluble intercellular adhesion molecule 1 and a decreased soluble c-kit level. Tumor necrosis factor-alpha and soluble c-kit were shown to be sensitive and specific parameters for graft-versus-host disease after bone marrow transplantation, and soluble Fas was shown to be a predictor of acute graft-versus-host disease after bone marrow transplantation.

Adolescent↗
PubMed2000

Relationships between changes in plasma concentrations of leptin before and after parturition and the timing of first post-partum ovulation in high-producing Holstein dairy cows.

During early lactation, dairy cattle are in negative energy balance and the delay to first post-partum ovulation depends on the time taken to recover from this situation. Lactating cows rely heavily on body fat to meet their requirements, leading to the suggestion that leptin, a hormone secreted mainly by adipocytes, is acting as a metabolic signal to sites that control the reproductive axis. The relationship between plasma leptin concentrations and the timing of the first ovulation post partum in 20 high-producing Holstein dairy cows, using a radioimmunoassay based on recombinant bovine leptin was studied. Plasma leptin concentrations declined after parturition, reached a nadir of 0.74 +/- 0.17 ng mL(-1) on 10.1 +/- 2.2 days after parturition (all values are mean +/- SEM). They then increased and became stable near the time of ovulation. Leptin concentrations averaged 1.81 +/- 0.31 ng mL(-1) in the 14 days prepartum, 1.32 +/- 0.21 ng mL(-1) in the post-partum preovulatory period and 1.61 +/- 0.24 ng mL(-1) in the post-ovulatory period. The differences between periods were significant (P<0.01). The interval from parturition to first ovulation averaged 25.9 +/- 2.0 days and was not correlated with the prepartum, preovulatory or post-ovulatory leptin values. However, the interval to first ovulation correlated significantly (r = 0.83 P < 0.0001) with the interval from parturition to the leptin nadir. These results show that plasma concentrations of leptin decrease in dairy cows in the early post-partum period and suggest that a delay in the recovery of leptin secretion increases the delay to the first ovulation.

Adipose Tissue↗
PubMed2000

Serum 4-hydroxy-2-nonenal-modified albumin is elevated in patients with type 2 diabetes mellitus.

4-Hydroxy-2-nonenal (HNE) is one of the major lipid peroxidation products with cytotoxic and mutagenic activity. It further reacts with protein residues such as histidine to generate stable Michael adducts. To evaluate the status of oxidative stress in the serum of type 2 diabetes mellitus, we constructed a sandwich enzyme-linked immunosorbent assay to measure serum HNE-modified albumin by the use of a specific monoclonal antibody (HNEJ-2) against HNE-histidine adducts as well as an antibody against human serum albumin. Serum of type 2 diabetes outpatients revealed significantly higher levels of HNE-modified albumin (736.1 +/- 34.2 pmol/ml, n = 54) than the matched nondiabetics (611.4 +/- 39.1 pmol/ml, n = 30; means +/- SEM; p = 0.018). However, no significant correlation was observed in diabetic outpatients between the levels of HNE-modified albumin and clinical parameters such as fasted blood glucose, HbA1c, diabetes duration, or complications. Our data demonstrated the increased formation of serum HNE-modified albumin in type 2 diabetic outpatients in the milieu between liver and vascular lumina, indicating the presence of oxidative stress.

Aged↗
PubMed2000

Removal effects of the Nd:YAG laser and Carisolv on carious dentin.

OBJECTIVE: The purpose of this study was to investigate the removal effect of the Nd:YAG laser irradiation and Carisolv on carious dentin. BACKGROUND DATA: Many previous studies have reported several simple and alternative techniques, such as lasers and chemicals, for caries removal. METHODS: Carisolv was applied on the surface of 20 extracted human anterior and molar teeth for 1 min and then the Nd:YAG laser was irradiated with a continuous water spray for another 1 min. The energy densities were varied from 2 to 6W with a repetition rate of 20 pps. As caries removal progressed, the cavity was carefully assessed by DIAGNOdent. Each lesion was photographed before and after treatment, and the treated cavity was observed microscopically using a stereoscope and with scanning electron microscope (SEM). Thermal change at the time of laser irradiation was measured by thermovision. RESULTS: Our results revealed that application of Carisolv followed by Nd:YAG laser irradiation at 4-6W pulse energy effectively removed dentin caries. The total procedure was usually repeated once or twice for complete caries removal. From the SEM study, it was found that the cavity surface treated with the laser revealed various patterns of microirregularity, often accompanied by microfissure propagation. There was also no smear layer. CONCLUSIONS: It was revealed that Nd:YAG laser and Carisolv could provide an alternative technique for caries removal instead of the conventional mechanical drilling and cutting.

Dental Caries↗
PubMed2000

Removal of gingival melanin pigmentation with the semiconductor diode laser: a case report.

OBJECTIVE: This investigation was performed to evaluate the possibility of the removal of canine gingival melanin pigmentation with the semiconductor diode (SCD) laser in vivo. SUMMARY BACKGROUND DATA: Recently, a semiconductor laser, which can ablate soft tissue, has been developed. It is already used in dentistry as well as in medicine. METHODS: The SCD laser was irradiated on the pigmented area of canine gingival surface with the irradiation output of 3W. The effect of the SCD laser irradiation was evaluated at the two intervals: immediately after irradiation and at 3 weeks following irradiation. In addition, histological examination was performed before irradiation and at the same intervals from the biopsies (4 microm) of unlased and lased areas. RESULTS: The SCD laser was effective in removing melanin pigmentation. In histological examination, neither inflammatory cell nor any tissue damage was observed with hematoxylin-eosin staining. At 3 weeks, there was a continuous healing process with the proliferation of squamous epithelial cells. CONCLUSIONS: SCD laser irradiation can be considered an alternative procedure for removal of melanin pigmentation.

Animals↗
PubMed2000

Caries-preventive effect of Er:YAG laser irradiation with or without water mist.

OBJECTIVE: This investigation was performed to evaluate the effect of Er:YAG laser irradiation on the acquired acid resistance of sound dental hard tissues to artificial caries formation by spectrophotometry, and the ultrastructure of lased areas was investigated by scanning electron microscopy (SEM) in vitro. BACKGROUND DATA: Although an Er:YAG laser has shown the most promise for hard tissue ablation, there have not been any dissolution studies to determine if this laser is suitable for caries preventive treatments. METHODS: An Er:YAG laser was used to irradiate the enamel and dentin samples from 20 extracted human molars at 400 mJ pulse energy with or without water mist. Samples were subjected to 2 microL of 0.1 M lactic acid solution (pH 4.8) for 24 hours at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry and the morphological changes were investigated by SEM. RESULTS: The lowest mean Ca2+ ppm was recorded in the samples irradiated without water mist, in those by irradiated with water mist, and in the unlased samples. SEM observation showed that the lased areas had melted and seemed to be thermally degenerated when irradiated without water mist. After acid demineralization, the thermally degenerated enamel or dentin surfaces were almost unchanged. CONCLUSIONS: The results of this study suggest that Er:YAG laser irradition with and without water mist appears to be more effective for caries prevention.

Dental Caries↗
PubMed2000

Effects of amrinone on ischaemia-reperfusion injury in cirrhotic patients undergoing hepatectomy: a comparative study with prostaglandin E1.

The effects of amrinone, a selective phosphodiesterase III inhibitor, on liver ischaemia reperfusion injury have not yet been clarified. Forty-five patients with hepatocellular carcinoma who underwent partial liver resection using Pringle's manoeuvre were studied. Patients were divided into three groups: those given amrinone, those given prostaglandin E1 (PGE1) and those not treated (controls). An indocyanine green (ICG) clearance test was performed before the operation and three times during surgery: just before induction of liver ischaemia, just after liver resection and 60 min after reperfusion. Blood lactate and base excess were measured at the same times. Systolic and diastolic arterial pressure, heart rate, cardiac index and oesophageal temperature were monitored. Aminotransferase levels were recorded the day before surgery, 1 h after operation and on the first and third postoperative days. These data were compared between groups. The ICG elimination rate, lactate and base excess in the amrinone group differed significantly from those in controls during the observation period (P = 0.03, P = 0.04 and P = 0.03, respectively). The differences between the PGE1 and control groups were not significant. There were no significant differences between the groups in perioperative vital signs, cardiac index or postoperative aminotransferase. Amrinone enhanced intraoperative ICG elimination in cirrhotic patients who underwent liver resection.

Aged↗
PubMed2000

Combined effects of meropenem and aminoglycosides on Pseudomonas aeruginosa in vitro.

To investigate combinations of antibiotics against Pseudomonas aeruginosa, the in vitro effects of combinations of meropenem with each of three aminoglycosides, arbekacin, amikacin and netilmicin, were evaluated using an agar dilution chequerboard technique. The combinations of meropenem and aminoglycosides were effective against almost all P. aeruginosa strains tested, which included meropenem-resistant strains. Increased synergic effects were observed in combinations that included arbekacin or amikacin. None of the combinations had an antagonistic effect. Most of the synergic and additive effects were achieved at clinically relevant concentrations.

Aminoglycosides↗
PubMed2000

Glutathione as an essential factor for chaperon-mediated activation of lactonizing lipase (LipL) from Pseudomonas sp. 109.

Pseudomonas sp. 109 produces a unique lipase (LipL) which efficiently catalyzes intramolecular transesterification of omega-hydroxyesters to form macrocyclic lactones. The production of the enzymatically active LipL requires a specific molecular chaperon (LimL protein) together with a low-M(r) lipase-activation-factor (LAF) of unknown structure. From 50 g of Pseudomonas cells, 2.15 mg of LAF was purified as a sulfobenzofurazanyl derivative after methanol extraction, derivatization, and C(18) reverse-phase HPLC. One-dimensional and two-dimensional 600 MHz (1)H-NMR and fast atom bombardment mass spectrometry (FAB-MS) revealed that LAF is glutathione. Because several SH compounds (L-cysteine and mercaptoethanol) were similarly effective to native LAF in the activation of LipL, and because only LipL contains two cysteinyl residues forming an intramolecular disulfide bond, it is concluded that the reduction of and reformation of the intramolecular disulfide bond of LipL is essential to liberate free and fully active LipL.

Bacterial Proteins↗
PubMed2000

Jasmonate induction of putrescine N-methyltransferase genes in the root of Nicotiana sylvestris.

Nicotine alkaloids are synthesized in the root of Nicotiana species, and their synthesis increases after insect attack, wounding and jasmonate treatment of the leaf. Putrescine N-methyltransferase (PMT) catalyzes the first committed step in nicotine biosynthesis. The expression patterns of the three Nicotiana sylvestris PMT genes (NsPMT1, NsPMT2, and NsPMT3) are reported in this study. Transcripts of the NsPMT genes were detected only in the root, and were up-regulated by methyl jasmonate treatment. When the 5'-flanking regions of NsPMT1, NsPMT2, and NsPMT3 were fused independently to beta-glucuronidase reporter gene and introduced into N. sylvestris by Agrobacterium-mediated transformation, all introduced transgenes were expressed in the cortex, endodermis, and xylem in the root, as well as upregulated by methyl jasmonate treatment. These qualitatively similar patterns of expression for the NsPMT genes are achieved with only 0.25 kb of their conserved 5'-flanking regions, which contained no known jasmonate-responsive elements.

Amino Acid Sequence↗
PubMed2000

Asaia bogorensis gen. nov., sp. nov., an unusual acetic acid bacterium in the alpha-Proteobacteria.

Eight Gram-negative, aerobic, rod-shaped and peritrichously flagellated strains were isolated from flowers of the orchid tree (Bauhinia purpurea) and of plumbago (Plumbago auriculata), and from fermented glutinous rice, all collected in Indonesia. The enrichment culture approach for acetic acid bacteria was employed, involving use of sorbitol medium at pH 3.5. All isolates grew well at pH 3.0 and 30 degrees C. They did not oxidize ethanol to acetic acid except for one strain that oxidized ethanol weakly, and 0.35% acetic acid inhibited their growth completely. However, they oxidized acetate and lactate to carbon dioxide and water. The isolates grew well on mannitol agar and on glutamate agar, and assimilated ammonium sulfate for growth on vitamin-free glucose medium. The isolates produced acid from D-glucose, D-fructose, L-sorbose, dulcitol and glycerol. The quinone system was Q-10. DNA base composition ranged from 59.3 to 61.0 mol% G + C. Studies of DNA relatedness showed that the isolates constitute a single species. Phylogenetic analysis based on their 16S rRNA gene sequences indicated that the isolates are located in the acetic acid bacteria lineage, but distant from the genera Acetobacter, Gluconobacter, Acidomonas and Gluconacetobacter. On the basis of the above characteristics, the name Asaia bogorensis gen. nov., sp. nov. is proposed for these isolates. The type strain is isolate 71T (= NRIC 0311T = JCM 10569T).

Acetic Acid↗
PubMed2000

Transfer of Acetobacter oboediens Sokollek et al 1998 and Acetobacter intermedius Boesch et al. 1998 to the genus Gluconacetobacter as Gluconacetobacter oboediens comb. nov. and Gluconacetobacter intermedius comb. nov.

Acetobacter oboediens Sokollek et al. 1998 and Acetobacter intermedius Boesch et al. 1998 are transferred to the genus Gluconacetobacter as Gluconacetobacter oboediens comb. nov. and Gluconacetobacter intermedius comb. nov. because, on the basis of their 16S rRNA gene sequences, the type strains of both species are located in the cluster of the genus Gluconacetobacter along with those of Gluconacetobacter xylinus, Gluconacetobacter europaeus, Gluconacetobacter hansenii, Gluconacetobacter liquefaciens (the type species) and Gluconacetobacter diazotrophicus. The significance of growth on mannitol agar and the presence of a ubiquinone isoprenologue composed of Q-10 is discussed for characterization of the genus Gluconacetobacter.

Acetobacter↗
PubMed2000

Enhancement in the perfection of orthorhombic lysozyme crystals grown in a high magnetic field (10 T).

Orthorhombic crystals of hen egg-white (HEW) lysozyme were grown in a homogeneous and static magnetic field of 10 T. All crystals grown at 10 T were oriented such that their crystallographic c axes were parallel to the magnetic field direction and showed a narrower average full-width at half-maximum (FWHM) of the rocking curve than those grown at 0 T. Rocking-width measurements were made at the BL-10A station at the Photon Factory, Tsukuba, Japan, using a high-resolution vertical-type four-circle diffractometer. Crystal perfection was evaluated using the FWHM of the rocking curve; the effects of the magnetic field on the quality of the crystals were examined by comparison of the FWHM of seven crystals grown at 10 and 0 T. The FWHMs of the reflections along the a, b and c axes decreased by 23.5, 35.3 and 27.8%, respectively, and those of other general reflections decreased by 17.4-42.2% in the crystals grown at high magnetic field. These results clearly showed that a magnetic field of 10 T improved the crystal perfection of the orthorhombic lysozyme crystals. As a result, the maximum resolution of X-ray diffraction increased from 1.3 A at 0 T to 1.13 A at 10 T. The magnetic field also affected the dimensions of the unit cell, increments being 0.2% for the a and c axes and 0.1% for the b axis, respectively. These facts suggest that the application of a high magnetic field during crystallization might result in remarkable enhancements in the diffraction power of protein crystals having magnetic anisotropy.

Animals↗
PubMed2000

A case of classic Kaposi's sarcoma in a Japanese man: detection of human herpes virus 8 (HHV-8) infection by means of polymerase chain reaction and immunofluorescence assay.

The recently discovered human herpes virus 8 (HHV-8) has been implicated in the pathogenesis of Kaposi's sarcoma (KS). Because classic KS in Japan is rare and the detection of HHV-8 DNA by polymerase chain reaction (PCR) has been successful only in limited cases, the frequency and role of HHV-8 infection in KS in Japan remain unclear. Herein we report a case of classic KS in a Japanese man whose HHV-8 infection was confirmed by the detection of lesional viral DNA and serum antibodies against lytic antigen.

Aged↗
PubMed2000

Immunohistochemical detection of carcinogen-DNA adducts in normal human prostate tissues transplanted into the subcutis of athymic nude mice: results with 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 3,2'-dimethyl-4-aminobiphenyl (DMAB) and relation to cytochrome P450s and N-acetyltransferase activity.

Human prostate tissue transplanted into nude mice was examined immunohistochemically for DNA adducts formed after administration of 3,2'-dimethyl-4-aminobiphenyl (DMAB) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Positive staining for DMAB- or PhIP-DNA adducts was evident in 70-95% of both epithelial and stromal cells in human prostate xenografts. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed a normal human prostate epithelial cell line (PrEC) to express both cytochrome P450 1A2 (CYP1A2) and N-acetyltransferase 2 (NAT2) mRNA, while a normal human prostate fibroblast cell line (NHPF) expressed NAT2, but not CYP1A2 mRNA. In addition, NAT2 and to a lesser extent CYP1A2 mRNAs were also found in four cases of normal human prostate tissues. The results suggest that initial activation of chemicals by liver CYP1A2 and subsequent metabolism by prostate NAT2 is a major pathway of DNA adduct formation in human prostate cells. Thus, the data suggest that human prostate has the potential to be targeted by environmental carcinogens.

Aged↗
PubMed2000

Birth cohort effects on incidence of lung cancers: a population-based study in Nagasaki, Japan.

Smoking prevalence remains high (around 60%) among Japanese males, but smoking initiation among males born in the 1930s decreased by approximately 10% due to economic difficulties following World War II. The present study was designed to examine whether this temporary decline in smoking initiation influenced the subsequent incidence of lung cancers, especially adenocarcinoma. Trends of lung cancer incidence by histological type in both sexes were investigated using data from the population-based cancer registry in Nagasaki, Japan, from 1986 through 1995. During this period, 5668 males and 2309 females were diagnosed as having lung cancer, and the overall incidence of lung cancers among both sexes remained stable. However, males aged 55 - 59 years showed a decrease in the age-specific incidence of adenocarcinoma and squamous-cell carcinoma (P < 0.05 and P < 0.01, respectively). In birth cohort analyses, the incidence of adenocarcinoma and squamous-cell carcinoma was lower in the 1935 - 1939 birth male cohort than in the successive cohorts. The incidence of lung cancers among females with low smoking prevalence did not change with birth cohort. The low smoking initiation among the 1935 - 1939 birth male cohort appeared to have resulted in a decreased incidence of adenocarcinoma and squamous cell carcinoma among middle-aged Japanese males. The present study suggests that smoking prevention has an effect in reducing the incidence of lung adenocarcinoma, as well as squamous-cell carcinoma, among smokers.

Adenocarcinoma↗