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Biomedical subjects

I Watanabe

Publications and source records attributed to I Watanabe.

At least 199 records · Page 11Linked to original sources
PubMed1995

[Ultrasonically guided needle biopsy of small mediastinal and peripheral pulmonary nodules].

From 1983 to 1993, we performed ultrasonically guided percutaneous needle biopsies on 320 thoracic tumors. Of these, 77 tumors were smaller than 3 cm in diameter and were peripherally located adjacent to the chest wall (n = 71) or in the posterior mediastinum (n = 6). We evaluated the efficacy and safety of UGNB for diagnosing these small lesions. The mean tumor size was 2.0 +/- 0.7 cm. Nine nodules were less than 1.0 cm in diameter, 38 were between 1.1 and 2.0 cm, and 30 were between 2.1 and 3.0 cm. Biopsies were done with a 17-gauge Trucut needle; a 21-gauge needle was used to aspirate specimens for cytological study. A definitive diagnosis was made in 31 (77%) of 40 malignant lesions and in 19 (51%) of 37 benign lesions. Complications included pneumothorax (n = 5) and hemoptysis (n = 3), but no special medications were needed. Thus, real-time sonographic guidance is a safe, easy, and reliable biopsy method for small pulmonary and mediastinal nodules adjacent to the chest wall.

Adult↗
PubMed1995

Shear bond strengths of four resin cements to cobalt-chromium alloy.

PURPOSE: To evaluate the shear bond strengths of four resin cements to cobalt-chromium (Co-Cr) alloy using two adhesive primers. MATERIALS AND METHODS: The adhesive luting agents Imperva Dual (ID), Panavia 21 (P21), Super-Bond C&B (SB) and Bistite Resin Cement (BR), and the adhesive primers Metal Primer (MP) and Cesead Opaque Primer (COP) were used. Two sizes of dental casting alloy disks were nonprimed or primed and cemented with each adhesive luting agent. The specimens were stored in water at 37 degrees C for 1 day, and then immersed alternately in water baths at 4 degrees C and 60 degrees C for 1 minute each for up to 100,000 thermocycles before shear mode testing at a cross-head speed of 0.5 mm/minute. RESULTS: The application of COP was effective for improving the shear bond strengths of ID, SB or BR to Co-Cr alloy compared with nonprimed specimens and those primed with MP. However, when Co-Cr alloy was cemented with P21, there were no significant differences in bond strengths between the three groups at all thermocycles.

Analysis of Variance↗
PubMed1994

Effect of thermal stress on glutathione metabolism in human erythrocytes.

This is the first experiment to investigate the effect of heat and cold stress on glutathione metabolism in human erythrocytes. We immersed men at three different water temperatures for 10 min. At 39 degrees C, no remarkable changes were observed. Levels of glutathione (GSH) decreased from 2.44 (0.14) to 1.80 (0.10) mumol.ml red blood cells-1 [mumol.ml RBC-1; mean (SEM); P < 0.0005] and those of lipid peroxides increased from 1.87 (0.03) to 2.06 (0.04) nmol.ml RBC-1 (P < 0.01) after the immersion at 42 degrees C. In contrast, levels of GSH increased from 2.46 (0.17) to 2.91 (0.17) mumol.ml RBC-1 (P < 0.05) and those of lipid peroxides did not change after the immersion at 25 degrees C. The activities of glutathione peroxidase decreased from 35.90 (1.83) to 34.33 (1.66) IU.g Hb-1 (P < 0.01) after the immersion at 42 degrees C; however, these activities did not change after the immersion at 25 degrees C. The activities of glutathione reductase (both active and inactive forms) showed no changes at any temperatures. These changes indicate that heat stress causes oxidative stress in the human body; however, cold stress is thought to augment the activity of the antioxidative defence system. It is suggested that body exposure to hot environmental conditions should not be recommended for patients suffering from a damaged antioxidative defence system.

Adult↗
PubMed1994

Dimensional changes related to ordering in an AuCu-3wt%Ga alloy at intraoral temperature.

OBJECTIVES: The purpose of this study was to evaluate the distortion behavior of a gold alloy with age-hardening ability at intraoral temperature induced by phase transformations. METHODS: Bridge-type specimens were prepared using AuCu-3wt%Ga alloy with age-hardening ability at 37 degrees C. Dimensional changes, hardness and surface roughness were measured. Transmission electron microscopy observation was carried out using AuCu-3wt%Ga discs aged at 37 degrees C for 30 d. RESULTS: Hardening was brought about rapidly in the initial stage of aging at 37 degrees C owing to ordering. The ordering was attributed to the formation of AuCu I and AuCu II superlattices. A linear contraction of 0.04% was induced by aging at 37 degrees C for 3 d. Distortion of the bridge-type specimen was brought about by a combination of linear contractions. The surface roughness increased in the initial stage of aging due to the surface relief effect of internal coherency strain caused by tetragonality. SIGNIFICANCE: The mode of distortion may be more advantageous for use in crown-type rather than inlay-type restorations, and the amount of contraction may not produce any problems in clinical use.

Chemical Phenomena↗
PubMed1994

Measurement methods for adhesion to dentine: the current status in Japan.

Adhesive test in vitro is performed to evaluate bonding materials. This paper describes methods of measuring adhesion to dentine currently used in Japan, and considers advantages and disadvantages. Various tests are used in Japan. Many factors-dentine substrate, storage conditions, bond strength test method-affect bonding to dentine. Bond strength test methods employed are divided into: tensile bond test and shear bond test. The test method used for the best prediction of clinical performance in bond strength evaluation is discussed. There has also been interest in bonding stability. At present, it may be difficult to propose an optimal standardized measuring method. Standardized experimental conditions in vitro which can simulate conditions in vivo are still under investigation.

Adhesiveness↗
PubMed1994

Purification and Characterization of Two Epoxide Hydrolases from Corynebacterium sp. Strain N-1074.

Enzymes II(a) and II(b), which catalyze the conversion of epichlorohydrin (ECH) to 3-chloro-1,2-propanediol (MCP), were purified from Corynebacterium sp. strain N-1074, which catalyzes the formation of (R)-MCP from prochiral 1,3-dichloro-2-propanol via ECH. The specific activity of enzyme II(a) for the formation of MCP from ECH was about 6.4-fold higher than that of enzyme II(b). Both enzymes catalyzed the conversion of 1,2-epoxides to the corresponding diol, although they differed in several enzymatic properties.

Journal Article↗
PubMed1994

Characterization of a novel enantioselective halohydrin hydrogen-halide-lyase.

Enzymes Ia and Ib of Corynebacterium sp. strain N-1074 exhibit halohydrin hydrogen-halide-lyase (H-lyase) activity, catalyzing the interconversion of halohydrins to epoxides and hydrogen halide. H-lyase B produced in a recombinant Escherichia coli strain carrying one of the enzyme genes of Corynebacterium sp. strain N-1074 was purified and characterized. The purified enzyme catalyzed the transformation of prochiral 1,3-dichloro-2-propanol (DCP) into R-rich epichlorohydrin (ECH). The apparent Km values for DCP, ECH, and chloride were calculated to be 1.03, 5.00, and 4.00 mM, respectively. Maximum activity for the conversion of DCP to ECH was found at pH 8.0 to 9.0, and that for the reverse reaction was found at about pH 5.0. H-lyase B seemed to be identical to enzyme Ib of Corynebacterium sp. strain N-1074 from the comparison of the properties of each. The properties of H-lyase B and H-lyase A, which had been previously purified from another recombinant carrying its gene from Corynebacterium sp. strain N-1074, were also compared.

Amino Acid Sequence↗
PubMed1994

Bonding to ground dentin by a phenyl-P self-etching primer.

Increasingly higher concentrations of Phenyl-P in 30% HEMA were used as dentin conditioners to improve the bonding of adhesive resins to smear layers. The maximum bond strength (10.4 MPa) was obtained at a concentration of 20% Phenyl-P. Transmission electron microscopy of fractured, lightly smeared, and compactly smeared dentin demonstrated that 20% Phenyl-P in 30% HEMA demineralized the dentin surface by partially dissolving mineral crystals from around collagen. When applied to smear layers, this resin system demineralized the smear layer and incorporated it into the applied resin which penetrated a short distance into the underlying dentin, thereby creating a hybrid layer that contained the original smear layer. This single-step conditioner/primer offers several advantages over previous bonding systems by permitting a single solution to serve as both a conditioner and a primer.

Animals↗
PubMed1994

Effects of alpha-human natriuretic peptide on renal hemodynamics and diuresis in dogs and perfused rat kidneys.

Effects of alpha-human atrial natriuretic polypeptide (alpha-hANP) on renal function were studied in anesthetized dogs and isolated perfused rat kidneys. Two doses of alpha-hANP were used to determine whether renal hemodynamics or tubular reabsorption is tha major factor in the diuretic action of alpha hANP. The excretion rates of sodium (Na) and inorganic phosphate (PO4) were evaluated to determine the site of diuretic action in the renal tubule. In dogs that received the smaller dose of alpha-hANP (5 ng.kg-1.min-1) infused into the renal arteries without changes in systemic or renal hemodynamics, urine volume (UV) and urinary Na excretion (UNaV) increased significantly. Fractional excretion of Na (FENa) was increased, while fractional excretion of PO4 (FEpo4) was unchanged, following the infusion of alpha-hANP. The calculated fractional Na reabsorption in the distal tubule (DTRNa) during the infusion of alpha-hANP was significantly suppressed. In dogs that received the a larger dose of alpha-hANP (50 ng.kg-1.min-1), the glomerular filtration rate (GFR), UV, and FENa were increased and DTRNa was decreased. In isolated rat kidneys perfused at a constant pressure, a lower concentration of alpha-hANP (0.5 ng.ml-1) in the perfusate caused diuresis and increased Na and PO4 excretion without any renal hemodynamic alterations. A higher concentration of alpha-hANP (5 ng.ml-1) increased GFR, Na and PO4 excretion. Since PO4 reabsorption is believed to occur primarily in the renal proximal tubule, these findings suggest that the diuretic action of alpha-hANP in smaller doses in induced by direct action on renal distal nephron.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Cloning of two halohydrin hydrogen-halide-lyase genes of Corynebacterium sp. strain N-1074 and structural comparison of the genes and gene products.

We cloned the genes from Corynebacterium sp. strain N-1074, for two halohydrin hydrogen-halide-lyase isoenzyme (hheA and hheB), which are involved in the transformation of alpha, beta-halohydrin into the corresponding epoxide and the reverse reaction. The nucleotide sequences of 1057 base pairs including the hheA gene and of 1130 base pairs including the hheB gene were analyzed. The predicted amino acid sequence of the hheA gene product consisted of 244 residues, and the calculated molecular weight was 26,465. The hheB gene had two sets of potential ribosome binding site and a possible initiation codon. The predicted amino acid sequences of the gene products consisted of 235 and 227 residues, and the calculated molecular weights were 26,179 and 25,236, respectively. Site-directed mutagenesis experiments strongly suggested dual translational initiation in the hheB gene. Comparison of the predicted amino acid sequences for the hheA and hheB genes found significant homology only in the carboxyl terminal region. An analysis of the upstream regions of the both hhe genes suggested the presence of putative epoxide hydrolase genes, which might be involved in further degradation of epoxide compounds.

Amino Acid Sequence↗
PubMed1994

Microwave ablation of the atrioventricular junction in vivo and ventricular myocardium in vitro and in vivo. Effects of varying power and duration on lesion volume.

Catheter ablation in ventricular tachycardia has achieved only limited success using direct current (DC) and radiofrequency (RF) energy, due to either high complication rates or a limited lesion size. Microwave energy represents a possible alternative source of energy for percutaneous ablation of the ventricular myocardium. However, an optimal method for titration of the dose of microwave energy to achieve the desired lesion volume has not yet been established. The safety and efficacy of microwave ablation of the atrioventricular (AV) junction were studied in 11 dogs in vivo. The relationship between lesion size following microwave ablation and the power output of or exposure duration to microwave energy was also examined at disparate sites in each superfused left ventricular epicardium in vitro. To observe the pathologic changes in the myocardium after microwave ablation, microwave ablation of the endocardium of the left ventricle was carried out in 9 dogs in vivo. Complete AV block was achieved in 10 of the above 11 dogs with a mean of 5 applications of microwave energy. The lesion volume in vitro demonstrated a parallel increase with power (r = 0.76) and duration (r = 0.81). The mean lesion volume at 30 sec was: at 10W, 0.8 +/- 1.6; 20 W, 34.7 +/- 10.3; 30 W, 34.7 +/- 22.4: 40 W, 64.7 +/- 64.4; 50 W, 87.2 +/- 42.3; 60 W, 85.8 +/- 38.1; 70 W, 124.7 +/- 36.5; 80 W, 134.2 +/- 49.0 mm3. The mean lesion volume at 80 W was: at 15 sec, 32.6 +/- 37.8; 30 sec, 101.2 +/- 46.4; 60 sec, 180.6 +/- 80.1; 120 sec, 291.8 +/- 122.7; and 180 sec, 459.3 +/- 204.6 mm3. The ablated lesions showed discrete, homogeneous coagulation necrosis with sharp margins from the adjacent normal myocardium. Microwave energy may thus be more effective than RF energy, and have a lower risk of complications and arrhythmogenesis than DC energy when used for ablation in ventricular tachycardia.

Animals↗
PubMed1994

[The diffusion route of Indian Ink injected into the infraorbital nerve trunk at the infraorbital foramen of the rabbit].

The purpose of this experimental study was to investigate the disseminating routes of viruses, bacteria, tumor cells and various substances along the trigeminal nerve sheaths. Thirty-four rabbits weighing approximately 3 kg were used for this study. After an intraperitoneal injection of sodium pentobarbital, the left infraorbital foramen was exposed surgically. Then, various amounts of Indian ink solution were injected with a syringe driver for continuous microinfusion into the infraorbital nerve trunk at a rate of 0.03 ml per minute. In all cases, during the appropriate state of general anesthesia, intravascular perfusion was performed with 10% folmaldehyde. The cranial and facial part of the rabbit were separated, decalcificated by Plank & Rychlo's method, dehydrated in an alcohol series, and embedded in 8% celloidin. Finally, 30 or 40 micrometer thick sections were stained with Hematoxilin-Eosin. The following results were obtained: (1) The Indian ink injected into the infraorbital nerve trunk at the infraorbital foramen diffused along the infraorbital nerve and maxillary nerve, but did not reach the trigeminal ganglion. (2) The Indian ink diffused along the nasal branches of the infraorbital nerve and reached a point near the nose tip. (3) The small branches of the infraorbital nerve and its accompanying vessels penetrated the bony wall of the maxillary sinus, and the Indian ink reached the proper layer of the sinus mucous membrane.

Animals↗
PubMed1994

Scanning electron microscopy of acinar cells of rat submandibular salivary glands.

1. The submandibular salivary gland of rats was observed by high-resolution scanning electron microscopy employing the aldehyde-osmium-DMSO-osmium method. 2. The intracellular membranous components and sponge-like structures of basement membrane containing the fine collagen fibrils of acinar cells were clearly identified in three-dimensional images. The granular endoplasmic reticulum and Golgi apparatus showed the luminal surface. The mitochondria were small, ranging in diameter from 0.3 to 0.5 microns, and revealed their cristae. The secretory granules ranged in diameter from 0.3 to 1.4 microns. Ribosome granules were attached to the surfaces of cisterns, and measured 20 to 25 nm in diameter. 3. The contact areas between the acinar cells revealed numerous cytoplasmic protrusions. In the striated duct cells, the mitochondria were arranged vertically and surrounded by basal infoldings of the plasma membranes. At high magnification, the mitochondrial cristae were visualized in their three-dimensional characteristics.

Animals↗
PubMed1994

[Collagen disease and vasculitis with manic and depressive symptoms].

Collagen diseases and vasculitis diseases are known to have severe disorders in many organs. Manic and depressive symptoms are also found in these diseases as one of central nervous system disorders. They are frequently observed in systemic lupus erythematosus, primary Sjögren's syndrome and rheumatoid arthritis. It is very difficult to diagnose and treat the manic-depressive states because there are many origins that cause the psychological disorder; immunological disorders (anti-cardiolipin antibodies, anti ribosomal protein P etc.), cerebral vasculitis, thrombosis, infections, endocrinological disorders, steroid induced psychosis and so on. There are few pathogenic studies to explain the manic-depressive symptom in these diseases.

Bipolar Disorder↗
PubMed1993

Changes in fibrinolytic parameters in male patients with type 2 (non-insulin-dependent) diabetes mellitus.

We examined changes in fibrinolytic parameters in male patients with diabetes mellitus (DM) and controls. DM patients were divided into three groups: patients without retinopathy, patients with simple retinopathy, and patients with proliferative retinopathy. Plasma levels of t-PA (tissue plasminogen activator) and t-PA-PAI-1 (plasminogen activator inhibitor-1) complex increased with increase in age, but those of PAI-1 (total and free) did not change in controls. On the other hand plasma levels of PAI-1 decreased with increase in age in DM patients. Plasma levels of t-PA, t-PA-PAI-1 complex, free and total PAI-1 increased with increase in body mass index in controls, but no significant changes were shown in these parameters in DM patients. When compared with controls, plasma levels of t-PA, t-PA-PAI-1 complex and PAI-1 were lower in DM patients. Plasma levels of UK (urokinase) and Lp(a) were higher in DM patients. ELT (euglobulin clot lysis time) was significantly shorter in DM patients than in controls. Patients without retinopathy showed increased fibrinolytic activities compared with those with retinopathy due to the increased levels of t-PA in plasma. These results seem to indicate that blood vessels release larger amounts of t-PA at the early stage of DM, then release being impaired at its advance stage. It is also suggested that the regulatory control mechanisms of fibrinolytic activity associated with mechanisms of fibrinolytic activity associated with change in age and body mass index are different between patients with DM and normal people.

Adult↗
PubMed1993

The effect of MCI-9042 on serotonin-induced platelet aggregation in type 2 diabetes mellitus.

MCI-9042, a potent inhibitor of 5HT2 receptor, was used to examine its effects on serotonin induced-aggregation of platelets obtained from patients with type 2 diabetes mellitus (DM). The extent of platelet aggregation induced by serotonin increased in DM patients without retinopathy, but the increase was further significant in DM patients with retinopathy. MCI-9042 as well as ketanserin, inhibited significantly serotonin induced-aggregation of platelets obtained from DM patients with retinopathy. MCI-9042 dose dependently inhibited platelet aggregation induced by serotonin and collagen. These results suggest that serotonin which may be released from platelets of DM patients may activate platelets together with collagen exposed on atherosclerotic endothelium and that MCI-9042 may be inhibitory to enhanced platelet aggregability under these conditions.

Adult↗