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Biomedical subjects

N Watanabe

Publications and source records attributed to N Watanabe.

At least 505 records · Page 28Linked to original sources
PubMed1996

High-fat hypercaloric diet induces obesity, glucose intolerance and hyperlipidemia in normal adult male Wistar rat.

There is strong evidence that genetic factors contribute to the development of obesity in humans as well as laboratory animals. Another important factor leading to obesity is an increase in energy intake. However, it is difficult to make normal rats obese by controlling daily food intake. There is no report of normal adult male Wistar rats becoming obese and diabetic on a high-fat diet. The aim of the present study was, therefore, to make normal adult Wistar rats obese by infusing high fat and hypercaloric diet through the cannula without disturbing the free movement and to investigate the influence of an increase in the caloric intake on body weight and glucose metabolism. High-fat hypercaloric diet (360 kcal/kg body wt./day; H group) or control diet (180 kcal/kg body wt./day; C group) was continuously infused into the stomach of normal adult male Wistar rats weighing approximately 300 g through gastric cannulas for 27 days. On day 28 after a 24-h fasting, serum concentrations of aspartate aminotransferase, alanine aminotransferase, total cholesterol, triglyceride, phospholipid, and free fatty acids (FFA) were determined, and intragastric glucose loading test (2 g/kg body wt.) was performed. The average weekly body weight gain in the H group was twice as much as that of the C group (40.0 +/- 2.4 vs. 19.4 +/- 1.9 g/week, P < 0.001). Serum levels of triglyceride, phospholipid, total cholesterol, and FFA were significantly elevated in the H group compared to those in the C group. Liver weight in the H group was significantly higher than that in the C group and showed steatosis. Pancreas weight (-13%) as well as protein (-12%), amylase (-53%) and trypsin content (-26%) were all reduced, whereas pancreatic DNA content was significantly increased in the H group compared to those in the C group. Serum glucose and insulin concentrations before and after glucose loading in the H group were significantly higher than those in the C group. Moreover, the insulin response relative to glucose response in the H group was significantly high compared to that in the C group, indicating the presence of insulin resistance. These results indicate that feeding of high-fat hypercaloric diet makes normal Wistar male adult rat obese associated with hyperlipidemia, hyperinsulinemia, and glucose intolerance.

Alanine Transaminase↗
PubMed1996

Distribution of D-aspartate oxidase and free D-glutamate and D-aspartate in chicken and pigeon tissues.

The presence of D-aspartate oxidase activity and D-glutamate was demonstrated for the first time in several tissues of chicken and pigeon. 2. The identification of the enzyme was based on substrate and inhibitors specificity of the activity as well as other requirements for the activity, and the amino acid was identified with HPLC analysis. 3. In each animal, the highest activity was found in the kidney. In chicken, the hepatic, renal and pancreatic activities were significantly higher in male than female. In pigeon, however, any significant gender difference was not observed. 4. A substantial amount of D-glutamate, as well as D-aspartate, was detected in each tissue, irrespective of species. 5. The contents of the free D-enantiomers were significantly different between two genders in the chicken kidney, heart and pancreas and pigeon liver and kidney. However, any common relationship was not observed between the contents and the D-aspartate oxidase activity.

Amino Acid Oxidoreductases↗
PubMed1996

Indirect labeling of macroaggregated albumin with indium-111 via diethylenetriaminepentaacetic acid.

It is ideal to perform a simultaneous pulmonary perfusion and ventilation scan in cases of suspected pulmonary thromboembolism. Indium-111 (111In)-diethylenetriaminepentaacetic acid (DTPA)-macroaggregated albumin (MAA) was designed for this purpose. MAA was conjugated with DTPA at a molar ratio of 1:100 and incubated with 111In-chloride for 30 min at room temperature. DTPA-MAA could be labelled with 111In above a 96% labelling efficiency without MAA particle aggregates making their particles larger than desirable. The obtained 111In-DTPA-MAA was intravenously injected into normal mice and their biodistribution was studied at 15 and 180 min after injection. A gamma camera image was obtained 15 min after injection. 111In-DTPA-MAA was stable in vitro and in vivo, and gave high uptake of murine lung in the biodistribution study and clearly visualized murine lung in the scintigraph. Using 111In-DTPA-MAA as a pulmonary perfusion agent, a simultaneous pulmonary perfusion and ventilation scan with technetium-99m-ventilation agents is able to be performed using the dual-isotope technique. 111In-DTPA-MAA may be a potential pulmonary perfusion agent.

Albumins↗
PubMed1996

Rat Kupffer cell-derived nitric oxide suppresses proliferation and induces apoptosis of syngeneic hepatoma cells.

BACKGROUND & AIMS: Evidence increasingly indicates that nitric oxide plays an important role in antitumor mechanisms. The aim of this study was to investigate the role of NO in the mechanisms regulating the proliferation and death of hepatoma cells cocultured with Kupffer cells. METHODS: Kupffer cells were isolated from male Wistar rats and cocultured with rat hepatoma AH70 cells. Proliferation was determined by calculating the number of total and 5-bromodeoxyuridine-positive AH70 cells. Apoptosis was assessed by electron-microscopic and fluorescence-microscopic observations and in situ nick end labeling method. Immunofluorescence and in situ hybridization studies were performed to investigate the induction of inducible NO synthase (iNOS). RESULTS: Kupffer cells reduced proliferation and induced apoptosis of AH70 cells, which were attenuated by the NO synthesis inhibitors NG-monomethyl-L-arginine and aminoguanidine. Increased inductions of iNOS messenger RNA and iNOS were observed in Kupffer cells cocultured with AH70 cells. Addition of monoclonal antibody directed against either rat CD18 or intercellular adhesion molecule 1 also attenuated the increased NO production of Kupffer cells and the alterations of AH70 cells. CONCLUSIONS: Kupffer cell-derived NO suppresses proliferation and induces apoptosis of hepatoma cells. The CD18 intercellular adhesion molecule 1-dependent adhesive interaction with hepatoma cells triggers NO production by Kupffer cells.

Animals↗
PubMed1996

Genomic diversity of mec regulator genes in methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis.

Low-affinity penicillin-binding protein PBP-2a encoded by mecA is closely related to methicillin resistance in staphylococci, and expression of PBP-2a is controlled by regulator elements encoded by mecR1 and mecI which are located adjacent to mecA on the chromosome. Deletion or mutation which occurred in mec regulator gene is considered to be associated with constitutive production of PBP-2a. The distribution of the mec regulator genes in 176 strains of Staphylococcus aureus and 33 strains of S. epidermidis isolated from a single hospital was studied by polymerase chain reaction amplification. Most clinical isolates of methicillin-resistant S. aureus (MRSA) (94.3%) and S. epidermidis (MRSE) (83.9%) possessed both mecI and mecR1 genes (type I), whereas no mec regulator genes were detected in mecA-negative isolates. In contrast, 7 MRSA and 5 MRSE isolates were found to have incomplete regulator genes, and they were classified into three groups; strains which lacked only mecI gene (type II), strains which lacked mecI and 3'-end of mecR1 gene (type III), and strains which lacked both regulator genes (type IV). Analysis of mecI gene from all the strains having mecI by restriction fragment length polymorphism after Mse I digestion indicated that three MRSA strains possessed one of the known point mutations identified previously. These findings indicated the predominance of a single type of MRSA possessing both mecI and mecR1 in the study period and also suggested a high genomic diversity in mec regulator region of staphylococci.

Cross Infection↗
PubMed1996

Different biodistribution of 99mTc-labelled chimeric mouse-human monoclonal antibody between athymic mice model and human.

Biodistribution of chimeric mouse/human monoclonal antibody against non-specific cross-reacting antigen (chNCA Ab) was studied in athymic mice and patients with metastatic bone disease. 99mTc-chNCA Ab showed a high labelling efficiency, stability and also a high binding ratio to human granulocytes. Since NCA showed cross-reactivity with carcinoembryonic antigen (CEA), animal experiments showed that 99mTc-chNCA Ab was accumulated in the xenografted tumour which expressed CEA, suggesting the preserved immunoreactivity of labelled materials. In the clinical study, injected 99mTc-chNCA Ab formed a high molecular weight complex immediately after intravenous administration and was trapped mainly in liver. The first-phase plasma half-life was 6.4 +/- 1.1 min. None of the patients showed adverse reaction or human antimurine or anti-chimeric antibody in their serum. 99mTc-chNCA Ab demonstrated remarkably different biodistribution between patients and the animal model and showed different pharmacokinetics from other murine and chimeric Abs reported previously. For safety HPLC analysis should be performed before clinical radioimmunodetection or radioimmunotherapy by incubating radiolabelled MAb with human serum under strict conditions.

Aged↗
PubMed1996

Seasonal variation in blood pressure in normotensive women studied by home measurements.

1. The factors influencing the seasonal variation in blood pressure measured at home in normotensive women were examined. 2. Sixteen female subjects (56.3 +/- 7.9 years old, mean +/- SD) measured their blood pressure and pulse rate at home each morning for more than 20 times per month for at least 1.5 years. Blood pressure and body weight were also determined in the office once or twice a month in that period. Monthly means of outdoor and indoor temperatures and daytime length were obtained from the Meteorological Observatory. The single cosinor method was used to evaluate circannual rhythm. 3. We observed a biphasic seasonal variation in self-recorded blood pressure measured at home, environmental temperature and daytime length but found no apparent seasonal variation in body weight and blood pressure measured in the office. The lowest levels of systolic and diastolic blood pressure measured at home were observed in July. The longest daytime length was recorded in June, while the highest outdoor temperature and indoor temperature were recorded in August, indicating that the longest daytime length preceded and the highest environmental temperature lagged behind the lowest level of blood pressure. The shortest daytime length is in December. The lowest outdoor and indoor temperature were observed in January, while the highest levels of self-recorded systolic blood pressure and diastolic blood pressure were in January and December, respectively. Half-amplitudes of self-recorded systolic and diastolic blood pressure were 2.6 +/- 1.0 mmHg and 2.0 +/- 0.8 mmHg, respectively. 4. These findings indicate the importance of a seasonal effect, i.e. daytime length and the environmental temperature, on the blood pressure of individuals.

Adult↗
PubMed1996

Nerve growth factor enhances survival and cytotoxic activity of human eosinophils.

Phenotypic change of blood-type eosinophils to tissue-type eosinophils is induced by various cytokines. We examined the effect of nerve growth factor (NGF) as a candidate for a constitutive cytokine which is able to induce the phenotypic change of eosinophils. The viability of human peripheral blood eosinophils cultured for 4 d was increased from a mean of 26% to a mean of 50% (P<0.001) by the addition of NGF (50 ng/ml). Cytotoxic activity of eosinophils determined by larvicidal activity was increased 2-3-fold by the addition of NGF (50 ng/ml) (P<0.05). Furthermore, eosinophil chemotactic activity of NGF was demonstrated by the blind well chamber method. Since NGF is produced constitutively from various kinds of cells in local tissues, it is suggested that NGF might be a cytokine responsible for phenotypic change to tissue type eosinophils in conditions without immune stimuli.

Cell Survival↗
PubMed1996

Acceleration of IgE responses by treatment with recombinant interleukin-3 prior to infection with Trichinella spiralis in mice.

Treatment of mice with recombinant interleukin-3 (rIL-3) accelerated an IL-4-dependent IgE production following infection with Trichinella spiralis. When mice were treated with a total of 1.5 x 10(4) units rIL-3 for 5 days before infection with 400 muscle larvae, the serum IgE level increased prominently on day 5. Acceleration of IgE responses was dependent on the dose of rIL-3 injected. Treatment of mice with a total of 10(3) units rIL-3 could accelerate IgE responses. IgE responses were detected by a sandwich enzyme-linked immunosorbent assay at least from day 3 in mice treated with rIL-3. Acceleration of IgE responses was inhibited by anti-IL-4 monoclonal antibody. In contrast to this, IgG1 and IgG2a responses were not suppressed by the anti-IL-4 treatment. IL-3 treatment could up-regulate IgE and IgG1 responses but not the IgG2a response. IL-3 treatment could also accelerate IgE responses in W/Wv mice infected with the parasites. These results suggest that IL-3 is involved in regulation of IgE responses in mice and that mast cells do not play an essential role in acceleration of IgE responses induced by rIL-3 treatment in this system.

Animals↗
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

Role of calcium in tumor necrosis factor-alpha production by activated macrophages.

The role of calcium in the production of tumor necrosis factor-alpha (TNF-alpha) by the lipopolysaccharide (LPS)-stimulated macrophage cell line, J774.1, was investigated. Flow cytometric measurement of intracellular calcium concentration ([Ca]i) using 2-(3,6-bis(acetyl-oxy)-2,7-dichloro-9H-xanthen-9-yl)benzoic acid (fluo-3)-loaded J774.1 cells revealed that LPS at more than 0.1 microgram/ml increased [Ca]i transiently in the presence or absence of serum, and that a mixture of a calcium chelator, ethyleneglycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA), and a calcium release blocker from intracellular store sites, 8-(diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8), inhibited the [Ca]i response induced by LPS. In concordance with this, production of TNF-alpha was inhibited by EGTA and/or TMB-8. These reagents also reduced the level of TNF-alpha mRNA significantly. These results indicate that the transient increase of [Ca]i plays a role in LPS-induced expression of TNF-alpha by the macrophage cell line.

Animals↗
PubMed1996

Activation of 20S proteasomes from spinach leaves by fatty acids.

In order to clarify the mechanism of activation plant 20S proteasomes by fatty acids, we examined the effects of oleic, linoleic and linolenic acids on the three of peptidase activities of purified 20S proteasomes from spinach leaves and compared them with the effects of SDS, a previously characterized activator of 20S proteasomes. The three fatty acids all activated the hydrolysis of succinyl-Leu-Leu-Val-Tyr-4-methylcoumaryl-7-amide (Suc-LLVY-MCA) and benzyloxycarbonyl-Leu-Leu-Glu-2-naphthyl-amide (Cbz-LLE-2NA) at low concentrations (one-third to one-sixth of that required for activation by SDS). The range of concentrations of linolenic acid for the activation of Suc-LLVY-MCA hydrolysis was very narrow. All the fatty acids inhibited the hydrolysis of tert-butoxycarbonyl-Leu-Arg -Arg-4-methylcoumaryl-7-amide (Boc-LRR-MCA) at extremely low concentrations (one-fifth to one-fifteenth of that required for the activation of the hydrolysis of Suc-LLVY-MCA and Cbz-LLE-2NA). In the case of hydrolysis of Suc-LLVY-MCA, SDS and the three fatty acids increased the Vmax value and decreased the apparent Km value to similar relative extents. In the case of hydrolysis of Boc-LLE-MCA, SDS and the three fatty acids also decreased the Km and increased the Vmax. However, SDS markedly increased Vmax. the curves representing the SDS-dependent activation were shifted to a lower range by the addition of linoleic acid, but the maximum activity at the optimum concentration of SDS was essentially unchanged. These results suggest that the activation by SDS and that by the fatty acids has an additive effect. The results imply that fatty acids, such as linolenic acid, might act as physiological regulators in plant cells.

Amino Acid Sequence↗
PubMed1996

A "changing stripe sign" in serial pulmonary perfusion imaging.

A stripe sign in pulmonary perfusion imaging is reported to be predictive of the absence of pulmonary embolism in the specific area of the stripe sign, and generally does not change on serial pulmonary perfusion imaging. The authors present the case of a patient with a stripe sign that disappeared on serial perfusion imaging without a ventilation abnormality. A "changing stripe sign" may raise suspicion for the possible existence of acute pulmonary embolism.

Aged↗
PubMed1996

Brain SPECT of Creutzfeldt-Jakob disease.

SPECT imaging with I-123 IMP or Tc-99m HMPAO was performed in two patients with Creutzfeldt-Jakob disease to evaluate abnormalities in brain perfusion. In the first patient, there was decreased perfusion of the left frontal, parietal, and temporal lobes. CT and MRI were negative. In the second patient, there was patchy perfusion and slightly decreased perfusion of the right hemisphere. MRI revealed slight brain atrophy and bilateral high intensity areas in the basal ganglia on T2 weighted images. Subsequent SPECT imaging revealed severely decreased perfusion of the entire brain. Subsequent MRI demonstrated severe brain atrophy.

Aged↗