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Biomedical subjects

A Tanaka

Publications and source records attributed to A Tanaka.

At least 397 records · Page 22Linked to original sources
PubMed1999

Mode of action of novel 2-(benzylamino)-4-methyl-6-(trifluoro- methyl)-1,3,5-triazine herbicides: inhibition of photosynthetic electron transport and binding studies.

Novel 2-(benzylamino)-4-methyl-6-(trifluoromethyl)-1,3,5-triazines have the same 1,3,5-triazine skeleton as atrazine, although some of them, for example, 2-(3-chlorobenzylamino)-4-methyl-6-(trifluoromethyl)-1,3,5-tria zin e [pI(50)(spinach) = 7.21], show a >3 times stronger photosynthetic electron transport inhibitory activity than atrazine [pI(50)(spinach) = 6.72]. The new triazines have only one amino group at the triazine ring, and their molecular shapes are different from atrazine. The replacement of the bound [(14)C]atrazine by 1,3,5-triazines was tested to determine whether the novel 1,3,5-triazine analogues exhibit the same binding pattern at the D1-protein as atrazine. It was found that [(14)C]atrazine bound to the D1-protein was replaced by the triazine tested by a clearly competitive interaction. Obviously, the novel 1,3,5-triazines are attached to the same binding niche as atrazine.

Electron Transport↗
PubMed1999

Internal tandem duplication of the FLT3 gene and clinical evaluation in childhood acute myeloid leukemia. The Children's Cancer and Leukemia Study Group, Japan.

We analyzed tandem duplication in the juxtamembrane (JM) domain of the FLT3 (FMS-like tyrosine kinase 3/FLK2, CD135) gene in 94 children with acute myeloid leukemia (AML) and evaluated its correlation with clinical features. Longer polymerase chain reaction (PCR) products were observed in five patients; 1/3 of M0, 119 of M1, 1/39 of M2, 1/9 of M3 and 1/12 of M5. The sequence analyses of abnormal PCR products showed that all the abnormal products were derived from tandem duplications involving the JM domain and that all the lengthened sequences were in-frame as we previously reported. Statistical analyses revealed a significantly lower incidence of the tandem duplication in childhood AML patients than in adult patients (P < 0.05), and significantly shorter disease-free survival in patients with mutant FLT3 than in patients with wild-type FLT3 (P < 0.05). Our results suggest that the tandem duplication in the JM domain of the FLT3 gene is not a frequent phenomenon but might be a factor of poor prognosis in childhood patients with AML.

Acute Disease↗
PubMed1999

Changes in gastric mucosal ulcerogenic responses in rats with adjuvant arthritis: role of nitric oxide.

AIM: To examine gastric mucosal ulcerogenic responses to indomethacin and HCl/ethanol in adjuvant arthritic (AA) rats. METHODS AND RESULTS: Arthritis was induced in male Dark Agouti (DA) rats by injection of Freund's complete adjuvant (FCA) into the right hind paw. The gastric ulcerogenic response to indomethacin was markedly worsened in AA rats, depending on the degree of arthritic change. This aggravation of indomethacin-induced gastric lesions in AA rats was significantly prevented by NG-nitro-L-arginine methyl ester (L-NAME) and amino-guanidine as well as dexamethasone. In contrast, the mucosal ulcerogenic response to HCl/ethanol was inhibited in AA rats. The suppression of HCl/ethanol-induced gastric lesions in AA rats was reversed almost totally by L-NAME and aminoguanidine as well as dexamethasone and partly by indomethacin. The expression of inducible nitric oxide synthase (iNOS) mRNA was observed in the stomach of AA rats but not of normal rats. Moreover, the luminal releases of nitric oxide (NO) metabolites as well as prostaglandin (PG) E2 were significantly increased in AA rats. CONCLUSIONS: The gastric mucosal ulcerogenic responses were modified in AA rats, in different manners depending on the irritants; an increase in response to indomethacin and a decrease in response to HCl/ethanol. These changes may both be accounted for by increased production of NO by iNOS, and the latter is also partly related to increased production of PGs.

Animals↗
PubMed1999

Thoughts and feelings of in-patients with advanced terminal cancer: implications for terminal care improvement.

The purpose of this study was to clarify how terminally ill patients think and feel while hospitalized, thereby providing some insight into improving the quality of terminal care. The subjects of the study were eight terminally ill patients with cancer. The researchers obtained the patients' consent and their doctors' permission prior to conducting the interviews. Individual, semi-structured interviews were conducted. The patients' thoughts and feelings were extracted and then categorized according to particular themes. As a result, we came up with four major categories: maintaining pain control, living an ordinary life, hoping for improvement of physical condition, and having family nearby. The desire to live life to its fullest given their situation, as well as to maintain a hopeful attitude about their future proved very important. The presence of family also played a crucial role. These factors must be taken into consideration in achieving better care for terminally ill patients.

Aged↗
PubMed1999

Invasion of the lacrimal system by basal cell carcinoma.

BACKGROUND: The rate of recurrence of basal cell carcinoma (BCC) in the periorbital region is higher than that in other areas because of the spread of the tumor along barrier structures. OBJECTIVE: A better understanding of the biological behavior of BCC in this area, in particular as it relates to the lacrimal system, should improve the outcome of surgery. METHODS: A study was made of two cases of BCC that developed in the periorbital region and invaded the lacrimal system. RESULTS: The tumors were found to have invaded the lacrimal system along the mucosal epithelium. Magnetic resonance imaging (MRI) did not suggest any abnormalities in this area. In one patient, the tumor had infiltrated the nasal cavity without destruction of the periorbital bone and nasal cartilage. A preoperative fiberscopic examination clearly demonstrated the involvement of the nasal cavity in this case. CONCLUSION: The lacrimal system is often invaded by BCC that originates from the periorbital region. Physicians and surgeons need to be well aware of the possibility of such aggressive infiltration by BCC.

Aged↗
PubMed1999

A future prediction type artificial heart system.

The demand of the biological system needs to be predicted to consider the quality of life (QOL) of a patient with an artificial heart system. The purpose of this study was the prediction of the imminent cardiac output and the predictive control for an artificial heart. For that purpose, autonomic nerve information was applied in this study. Nervous sympathicus action potentials were measured, and a prediction function of cardiac output was made using the sympathetic tone and preload and after-load measurement with multiple regression analysis. The predicted value showed significant correlation with the measured value after 2.9 s. Currently, however, long-term instrumentation of the nervous sympathicus potential is difficult. Thus, hemodynamic fluctuations, which recently have attracted attention, were used in this study. A prediction function using the Mayer wave, which represented nervous sympathicus, was determined. As a result, mid-term prediction became possible. Furthermore, a measurement of the vagal nerve was used as a possible long-term prediction parameter. For long-term prediction, Hurst exponent analysis was used in this study. Vagal nerve discharges in the changing position showed alteration of long-term determination. In conclusion, the future prediction control of an artificial heart takes shape using these prediction functions.

Action Potentials↗
PubMed1999

Vagal nerve activity recording in the awake condition for the control of an artificial heart system.

To detect useful information for an artificial heart control system, we paid attention to the autonomic nervous system. For stable recording, we used vagal nerve activity in chronic animal experiments using healthy adult goats in an awake condition because this nerve was sufficiently bold and large enough. Vagal nerve discharges were successfully recorded from awake goats. They were synchronized with respiration and responded to the hemodynamic changes induced by drug administration, suggesting that they may provide useful information for an artificial heart control algorithm. For automatic control, some time delay plays a vitally important role. Thus, predictive control for an artificial heart system may be desirable. It may be embodied by the use of autonomic nerve information.

Action Potentials↗
PubMed1999

Peripheral vascular resistances during total left heart bypass with an oscillated blood flow.

For development aimed at a totally implantable type ventricular assist device (VAD), the vibrating flow pump (VFP) has been developed at Tohoku University. A transcutaneous energy transmission system (TETS) using amorphous fibers was developed to power the totally implantable VAD system. The VFP works at a high frequency compared to that of a natural heart of a biological system. It is a frequency of 10-50 Hz. In this research, animal experiments with left heart bypass were carried out with healthy adult goats. For comparison between nonpulsatile flow and oscillated flow, a rotary pump (RP) and the VFP were used in the experiments. For the achievement of total left heart bypass, left ventricular approaches were carried out, and blood was pumped from the left ventricle to the descending aorta. Adequate support of the left heart was provided by both pumps. In terms of the results, the vascular resistances tended to decrease during the use of both pumps during 100% bypass driving. When we compared these pumps at the same flow rate, the resistances during RP driving were significantly smaller than those during VFP driving. These results may suggest that the influences of the VFP upon the peripheral vessels may be relatively small compared to those of the RP. This may be an important result when a stable hemodynamic condition is required during artificial circulation. The VFP was considered as a candidate for a totally implantable VAD as a result.

Animals↗
PubMed1999

Detection of the cardiac function by fractal dimension analysis.

Nonlinearity in circulation control attracts attention because nonlinearity is thought to be essential in the function of the living body. Many investigators have pointed out that the analysis of heart rate variability in particular is important in the analysis of autonomic nerve and cardiac function evaluation. Heart rate variability shows nonlinear behavior. However, until the present, many reports have been premised on linearity; linear correlation by frequency analysis has been used by many studies. However, in terms of this methodology, there is a problem applying it to the nonlinear living body. Therefore, fractal and chaos methodology has been used. The ascertainment of cardiac function has become important in allowing the clinical stage of a ventricular assist system to be successful. The purpose of this study was cardiac function evaluation by a methodology that was premised on nonlinearity. Chaos and fractal theory was used as a nonlinear dynamic theory. As a methodology of measurement, the volume of the left ventricle was used rather than an electrocardiogram, the waveform of arterial blood pressure. The volume was measured using acoustic quantification (AQ) ultrasonic echocardiography. Using these methodologies, the time series of many patients were analyzed. For example, drug administration was attempted in this study, and it was found that some drugs like ACE inhibitors showed a significant effect upon nonlinear dynamics in the cardiovascular system. The result, which attempted cardiac function evaluation by these various methodologies, is reported.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

Comparison of the activities of enzymes related to glycolysis and gluconeogenesis in the liver of dogs and cats.

Activities of enzymes related to glucose metabolism were measured in canine and feline liver. There were no significant differences in plasma glucose and immunoreactive insulin concentrations between dogs and cats. Glucokinase activities were absent in feline liver, however, activities of other glycolytic enzymes such as hexokinase, phosphofructokinase and pyruvate kinase, were significantly higher than those in canine livers. Activities of rate limiting enzymes of gluconeogenesis such as pyruvate carboxylase, fructose-1, 6-bisphosphatase and glucose-6-phosphatase in feline livers were significantly higher than those in canine livers.

Animals↗
PubMed1999

Exposed peptide core of IgA1 hinge region in IgA nephropathy.

BACKGROUND: The human IgA1 hinge region is a very unique O-linked glycopeptide, and its sialylation and galactosylation recently were reported to be defective in the serum IgA1 derived from patients with IgA nephropathy (IgAN). This study was performed to examine the underglycosylation of the IgA1 hinge region and consequent exposure of the peptide core in IgAN. METHODS: A polyclonal antibody against a synthetic human IgA1 hinge peptide, PVPSTPPTP SPSTPPTPSPS, (anti-sHP ab) was raised in rabbits and shown specifically to recognize the IgA1 which was treated with neuraminidase, beta-galactosidase and alpha-N-acetylgalactosaminidase. The reactivity of the anti-sHP ab against the purified serum IgA1 was compared among the following three groups: 39 patients with IgAN, 30 patients with other renal diseases (ORD) and 21 healthy controls (HC) using an enzyme-linked immunosorbent assay. RESULTS: The reactivity was significantly higher in the IgAN group (mean +/- SD of OD 490 nm: 0.327 +/- 0.059) than in the ORD group (0.274 +/- 0.043, P=0.0002) and in the HC group (0.265 +/- 0.037, P<0.0001). No significant difference was observed between the latter two groups. The frequency of positive cases (> mean +/- 2SD of HC) was 46.2% (18/39) in the IgAN group, 6.7% (2/30) in the ORD group and 0% (0/21) in the HC group. CONCLUSIONS: It was suggested that the peptide core of the IgA1 hinge region is exposed aberrantly by a defective N-acetylgalactosaminylation and plays a possible role in the pathogenesis of IgAN.

Adolescent↗
PubMed1999

Guanidine hydrochloride-induced denaturation of Pseudomonas cepacia lipase.

The guanidine hydrochloride-induced denaturation of Pseudomonas cepacia lipase (PCL) was studied at pH 7 by monitoring the changes in the fluorescence and circular dichroism of the enzyme. The denaturation was irreversible as a whole, and the addition of Ca2+ ions decreased the velocity of the denaturation. The denaturation process was well explained consistently by a two-step mechanism, as follows: [see equation in text] where N is the native state of PCL, D(I) an intermediate denatured-state which can be refolded into the native state, and D(F) the final denatured-state that can not be renatured. Ethanol (10%) increased the denaturation velocity by decreasing the refolding step, D(I) + Ca2+ --> N x Ca2+, which would be caused by the stabilization of D(I) by ethanol.

Burkholderia cepacia↗
PubMed1999

Three-dimensional analysis of protein aggregate body in Saccharomyces cerevisiae cells.

Modified genes of peroxisomal isocitrate lyase of Candida tropicalis (CT-ICL) were constructed and expressed in Saccharomyces cerevisiae cells. We observed subcellular localization of expressed products of the mutant CT-ICL genes by immunoelectron microscopy. An unknown structure termed a protein aggregate body (PAB) storing the expressed product was observed in cytoplasm in various mutants (Kamasawa et al. (1996) J. Electron Microsc. 45: 491-497). We chose two typical cells harbouring the mutant ICL genes delta 550 and delta 237-339 to analyse the ultrastructure and three-dimensional (3D) structure of PABs. The PABs had a homogeneous matrix with a wavy periphery in the cell image using a high-pressure freezing fixation method. Although PABs could not be separated from the cytoplasm or mitochondria under a confocal fluorescence microscope, 3D reconstruction of serial electron micrographs clearly showed the PAB was an independent structure of varying size and had the shape of an incomplete sphere. A cell was sometimes observed to have multiple PABs.

Candida↗
PubMed1999

Insertional mutagenesis and cloning of the genes required for biosynthesis of the host-specific AK-toxin in the Japanese pear pathotype of Alternaria alternata.

The Japanese pear pathotype of Alternaria alternata causes black spot of Japanese pear by producing a host-specific toxin known as AK-toxin. Restriction enzyme-mediated integration (REMI) mutagenesis was used to tag genes required for toxin biosynthesis. Protoplasts of a wild-type strain were treated with a linearized plasmid along with the restriction enzyme used to linearize the plasmid. Of 984 REMI transformants recovered, three produced no detectable AK-toxin and lost pathogenicity on pear leaves. Genomic DNA flanking the integrated plasmid was recovered from one of the mutants. With the recovered DNA used as a probe, a cosmid clone of the wild-type strain was isolated. Structural and functional analyses of an 8.0-kb region corresponding to the tagged site indicated the presence of two genes. One, designated AKT1, encodes a member of the class of carboxyl-activating enzymes. The other, AKT2, encodes a protein of unknown function. The essential roles of these two genes in both AK-toxin production and pathogenicity were confirmed by transformation-mediated gene disruption experiments. DNA gel blot analysis detected AKT1 and AKT2 homologues not only in the Japanese pear pathotype strains but also in strains from the tangerine and strawberry pathotypes. The host-specific toxins of these two pathotypes are similar in structure to AK-toxin. Homologues were not detected in other pathotypes or in non-pathogenic strains of A. alternata, suggesting acquisition of AKT1 and AKT2 by horizontal transfer.

Alternaria↗
PubMed1999

Reconstruction of full-thickness lower eyelid defects using a blepharoplasty technique with a hard palate mucosal graft.

The authors report a method of reconstruction of a full-thickness lower eyelid defect using a blepharoplasty technique utilizing excess skin of the lower eyelid with a hard palate mucosal graft. In all patients the hard palate mucosa took well, and good functional and aesthetic results were obtained. The most suitable indication of this technique might be for the defect occurring horizontally (for which direct closure is difficult to apply) and located in the lateral side of the lower eyelid (when a large amount of excess skin can be utilized). The authors conclude that although the shape and size of the defect to which this method can be applied is restricted, this is a useful option in the reconstructive methods of a full-thickness lower eyelid defect.

Aged↗
PubMed1999

Efficacy of endoscopic static pressure/area assessment of the passive pharynx in predicting uvulopalatopharyngoplasty outcomes.

OBJECTIVES/HYPOTHESIS: Although uvulopalatopharyngoplasty (UPPP) is an attractive surgical treatment for obstructive sleep apnea (OSA), the unpredictable outcome limits application of the procedure. Since UPPP corrects only retropalatal airway (RP) patency, we hypothesized that response to UPPP is determined by collapsibility of the retroglossal airway (RG), where UPPP does not correct. METHODS: We estimated closing pressure (Pclose) for each pharyngeal segment by endoscopically obtaining the static pressure/area relationship of the passive pharynx in completely paralyzed and anesthetized patients with sleep-disordered breathing (n = 41) before UPPP. Preferable response to UPPP was defined as the number of oxygen dips (ODI), obtained by nocturnal oximetry, less than 10 h(-1) after UPPP. RESULTS: Patients with negative Pclose at RG responded to UPPP significantly better than those with positive Pclose at RG (22/30 [73%] vs. 3/11 [27%], P<.05). ODI after UPPP was significantly correlated with age, Pclose at RP, and Pclose at RG. CONCLUSIONS: Endoscopic assessment of anatomic abnormality of the pharynx in paralyzed patients with sleep-disordered breathing under general anesthesia has clinical value for the improvement of UPPP outcome.

Adult↗
PubMed1999

The Arabidopsis dwarf1 mutant is defective in the conversion of 24-methylenecholesterol to campesterol in brassinosteroid biosynthesis.

Since the isolation and characterization of dwarf1-1 (dwf1-1) from a T-DNA insertion mutant population, phenotypically similar mutants, including deetiolated2 (det2), constitutive photomorphogenesis and dwarfism (cpd), brassinosteroid insensitive1 (bri1), and dwf4, have been reported to be defective in either the biosynthesis or the perception of brassinosteroids. We present further characterization of dwf1-1 and additional dwf1 alleles. Feeding tests with brassinosteroid-biosynthetic intermediates revealed that dwf1 can be rescued by 22alpha-hydroxycampesterol and downstream intermediates in the brassinosteroid pathway. Analysis of the endogenous levels of brassinosteroid intermediates showed that 24-methylenecholesterol in dwf1 accumulates to 12 times the level of the wild type, whereas the level of campesterol is greatly diminished, indicating that the defective step is in C-24 reduction. Furthermore, the deduced amino acid sequence of DWF1 shows significant similarity to a flavin adenine dinucleotide-binding domain conserved in various oxidoreductases, suggesting an enzymatic role for DWF1. In support of this, 7 of 10 dwf1 mutations directly affected the flavin adenine dinucleotide-binding domain. Our molecular characterization of dwf1 alleles, together with our biochemical data, suggest that the biosynthetic defect in dwf1 results in reduced synthesis of bioactive brassinosteroids, causing dwarfism.

Alleles↗