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Biomedical subjects

T Okada

Publications and source records attributed to T Okada.

At least 217 records · Page 12Linked to original sources
PubMed2000

[A case of bladder hemangioma showing bladder tamponade during late pregnancy].

We report a case of bladder hemangioma manifesting bladder tamponade during pregnancy. A 25-year-old woman at 36 weeks of gestation was admitted with a two-week history of gross hematuria and clot retention. Blood hemoglobin concentration was 6.3 g/dl. After blood transfusion and Caesarian section, cystoscopy was performed. Bleeding was noticed from a strawberry-like tumor 5 mm in diameter near the right ureteral orifice, which was easily resected endoscopically. Histopathological diagnosis was cavernous hemangioma of the urinary bladder. This is the first report of a case of bladder hemangioma during pregnancy.

Adult↗
PubMed2000

[Effect of dietary protein restriction and influence of proteinuria on progression of type 2 diabetic renal failure].

PURPOSE: This study investigated the effect of dietary protein restriction on disease progression and how it is influenced by proteinuria in patients with type 2 diabetic nephropathy(DN) and renal failure. METHODS: One hundred and six type 2 DN patients whose baseline creatinine clearance(Ccr) values were 29 +/- 12 ml/min/1.73 m2 were maintained on a diet containing 0.66 +/- 0.05 g/kg/day of protein. They were classified into 3 groups according to mean dietary protein intake(DPI) estimated from urinary urea nitrogen excretion during the follow-up period of 23 +/- 14 months(I, < 0.7 g/kg/day; II, 0.7-0.89 g/kg/day; III, > or = 0.9 g/kg/day). Furthermore, they were divided into 3 subgroups according to mean urinary protein excretion(UP) during the follow-up period (a, > or = 5.0 g/day; b, 2.0-4.99 g/day; c, < 2.0 g/day). Their rates of decline of Ccr(D-Ccr) and the changes in UP were examined. RESULTS: There were no significant differences in D-Ccr among Group Ia, IIa, and IIIa(1.1 +/- 0.6, 1.5 +/- 0.7, 1.2 +/- 0.6 ml/min/1.73 m2/month), among Group Ib, IIb, and IIIb(0.6 +/- 0.3, 0.7 +/- 0.4, 0.8 +/- 0.4 ml/min/1.73 m2/month), and also among Group Ic, IIc, and IIIc(0.1 +/- 0.3, 0.2 +/- 0.2, 0.2 +/- 0.6 ml/min/1.73 m2/month). On the other hand, significant differences were revealed in D-Ccr among Group Ia, Ib, and Ic, among Group IIa, IIb, and IIc, and among Group IIIa, IIIb, and IIIc. There were no significant differences in final UP and minimum UP during follow-up among 3 groups of different DPI levels in patients with 5.0 g/day < or = baseline UP(n = 49) and in patients with 2.0 < or = baseline UP < 5.0 g/day(n = 37). However, significant correlations were demonstrated between D-Ccr and the relative changes in UP between baseline and minimum during the follow-up period in both patients(r = 0.49, 0.48, p < 0.001, p < 0.01). CONCLUSIONS: Irrespective of the level of dietary protein restriction, proteinuria has a great influence on disease progression, and the reduction in UP correlates with retardation of renal function loss in patients with type 2 DN and renal failure.

Aged↗
PubMed2000

[A case of neurocysticercosis presenting as focal seizure].

In Japan neurocysticercosis is a rare disease. We report a case of neurocysticercosis with a review of the literature. A 29-year-old man presented focal seizure on the left side. Physical and neurological findings on admission were unremarkable. CT and MRI showed a mass with ring-like enhancement and perifocal edema in the right frontal lobe, as well as multiple small masses with calcification. The main mass measuring 8 mm in diameter, was suspected as the eliptogenic focus, and was totally removed via the transcortical approach. Postsurgically seizures did not recur, and histological examination of the mass confirmed a cysticercus. A therapeutic course of albendazole and praziquantel administered postsurgically was effective for the multiple intraparenchymal masses.

Adult↗
PubMed2000

[Severe lightning pain during spinal anesthesia in a patient with diabetic neuropathy].

A 71-year-old woman with diabetic neuropathy who had undergone amputation of the right lower leg for diabetic gangrene 4 years previously, experienced severe lightning pain in both legs during spinal anesthesia. She was scheduled for skin grafting for a burn ulcer on her left foot. Her preoperative physical examination revealed hypesthesia in both legs due to diabetic neuropathy. Spinal anesthesia was performed with a combined spinal-epidural needle at the L 4-5 interspace using 2.0 ml of 0.3% hyperbaric dibucaine in the left lateral position. The region of hypesthesia was spread below Th 4. Ten minutes later, she complained of severe lightning pain in both legs and midazolam 1 mg was administered intravenously against agitation. The severe lightning pain diminished after the administration of pentazocine 7.5 mg intravenously in the recovery room. There was no worsening of neurological findings 5 hours later when the effect of spinal anesthesia disappeared. This clinical picture seems to be different from that of reported cases of phantom limb pain during spinal anesthesia in which severe lightning pain occurred in both legs. This case suggests that patients with diabetic neuropathy might develop severe lightning pain during spinal anesthesia using dibucaine.

Aged↗
PubMed2000

[Assessment of cardiac sympathetic nerve activity in children with chronic heart failure using quantitative iodine-123 metaiodobenzylguanidine imaging].

OBJECTIVES: Cardiac sympathetic nerve activity in children with chronic heart failure was examined by quantitative iodine-123 metaiodobenzylguanidine (MIBG) myocardial imaging in 33 patients aged 7.5 +/- 6.1 years (range 0-18 years), including 8 with cardiomyopathy, 15 with congenital heart disease, 3 with anthracycrine cardiotoxicity, 3 with myocarditis, 3 with primary pulmonary hypertension and 1 with Pompe's disease. METHODS: Anterior planar images were obtained 15 min and 3 hr after the injection of iodine-123 MIBG. The cardiac iodine-123 MIBG uptake was assessed as the heart to upper mediastinum uptake activity ratio of the delayed image (H/M) and the cardiac percentage washout rate (%WR). RESULTS: The severity of chronic heart failure was class I (no medication) in 8 patients, class II (no symptom with medication) in 9, class III (symptom even with medication) in 10 and class IV (late cardiac death) in 6. H/M was 2.33 +/- 0.22 in chronic heart failure class I, 2.50 +/- 0.34 in class II, 1.95 +/- 0.61 in class III, and 1.39 +/- 0.29 in class IV (p < 0.05). %WR was 24.8 +/- 12.8% in chronic heart failure class I, 23.3 +/- 10.2% in class II, 49.2 +/- 24.5% in class III, and 66.3 +/- 26.5% in class IV (p < 0.05). The low H/M and high %WR were proportionate to the severity of chronic heart failure. CONCLUSIONS: Cardiac iodine-123 MIBG showed cardiac adrenergic neuronal dysfunction in children with severe chronic heart failure. Quantitative iodine-123 MIBG myocardial imaging is clinically useful as a predictor of therapeutic outcome and mortality in children with chronic heart failure.

3-Iodobenzylguanidine↗
PubMed2000

[Development of blood cell measurement].

Automated blood cell analyzers used in hematology laboratories are required to measure many specimens rapidly and efficiency has been realized through increasing the measurement parameters and throughput volume in one instrument. In the period of 1950's through the early part of 1960's, only red blood cells and white blood cells could be counted. In 1965, Technicon Corporation developed an instrument which can measure the number of blood cells, hemoglobin, hematocrit and calculate corpuscular constants simultaneously. Thereafter, the methodologies for simultaneous platelet measurement and precise determination of blood cell distribution have been developed. Then, the development of new reagents has achieved three part differentials in the distribution of white blood cells. Thanks to this development, microscopic white blood cell differentials has been replaced by blood cell analyzers in screening tests. Though blood cell analyzers may be further improved by expanding of the number of parameters available for simultaneous measurements, meeting social needs in the new era will not be possible without the creation and realization of new concepts employing new technologies such as IT (Information Technology).

Automation↗
PubMed2000

The effect of habituation and plane of rotation on vestibular perceptual responses.

A technique was applied to assess vestibular sensation without reference to external spatial, position cues. The stimuli were stopping responses to velocity-steps of 90 deg/s in the dark. Subjects indicated their perceived angular velocity by turning a flywheel connected to a tachogenerator. Two separate experiments were conducted. In one, subjects were rotated in yaw about an earth-vertical axis before and after prolonged rotational or visual (optokinetic) stimuli. In the second experiment, subjects were rotated in roll supine, with either the head ('roll centred') or the feet ('roll eccentric') on the axis of rotation. The two aims of the paper were to (i) examine the effect of repetitive vestibular and optokinetic stimulation on the time constant of decay of vestibular sensation in yaw; (ii) to compare vestibular sensation responses to rotation in roll both with and without the addition of a Z-axis centrifugal force. The pre-habituation sensation response in yaw decayed exponentially with a median time constant of 12.8 s. The duration of the sensation responses were significantly reduced following both prolonged vestibular and optokinetic stimulation. The reduction in vestibular responses following prolonged visual and vestibular stimuli, 1) is likely to occur in velocity storage mechanisms mediating ocular and perceptual responses, 2) may represent a mechanism for reducing the disorientating consequences of visual-vestibular conflict and 3) supports the use of optokinetic stimuli as a treatment for vestibular patients. The time constant of the sensation responses in roll was shorter and not significantly influenced by head position: 5.7 s in the head-centred position compared to 4.7 s in the eccentric head position. Therefore, perceptual as well as ocular responses to rotation in roll are determined primarily by cupula dynamics and not influenced by velocity storage.

Adult↗
PubMed1999

RA-GEF, a novel Rap1A guanine nucleotide exchange factor containing a Ras/Rap1A-associating domain, is conserved between nematode and humans.

A yeast two-hybrid screening for Ras-binding proteins in nematode Caenorhabditis elegans has identified a guanine nucleotide exchange factor (GEF) containing a Ras/Rap1A-associating (RA) domain, termed Ce-RA-GEF. Both Ce-RA-GEF and its human counterpart Hs-RA-GEF possessed a PSD-95/DlgA/ZO-1 (PDZ) domain and a Ras exchanger motif (REM) domain in addition to the RA and GEF domains. They also contained a region homologous to a cyclic nucleotide monophosphate-binding domain, which turned out to be incapable of binding cAMP or cGMP. Although the REM and GEF domains are conserved with other GEFs acting on Ras family small GTP-binding proteins, the RA and PDZ domains are unseen in any of them. Hs-RA-GEF exhibited not only a GTP-dependent binding activity to Rap1A at its RA domain but also an activity to stimulate GDP/GTP exchange of Rap1A both in vitro and in vivo at the segment containing its REM and GEF domains. However, it did not exhibit any binding or GEF activity toward Ras. On the other hand, Ce-RA-GEF associated with and stimulated GDP/GTP exchange of both Ras and Rap1A. These results indicate that Ce-RA-GEF and Hs-RA-GEF define a novel class of Rap1A GEF molecules, which are conserved through evolution.

Amino Acid Sequence↗
PubMed1999

Molecular and functional characterization of a novel mouse transient receptor potential protein homologue TRP7. Ca(2+)-permeable cation channel that is constitutively activated and enhanced by stimulation of G protein-coupled receptor.

Characterization of mammalian homologues of Drosophila transient receptor potential protein (TRP) is an important clue to understand molecular mechanisms underlying Ca(2+) influx activated in response to stimulation of G(q) protein-coupled receptors in vertebrate cells. Here we have isolated cDNA encoding a novel seventh mammalian TRP homologue, TRP7, from mouse brain. TRP7 showed abundant RNA expression in the heart, lung, and eye and moderate expression in the brain, spleen, and testis. TRP7 recombinantly expressed in human embryonic kidney cells exhibited distinctive functional features, compared with other TRP homologues. Basal influx activity accompanied by reduction in Ca(2+) release from internal stores was characteristic of TRP7-expressing cells but was by far less significant in cells expressing TRP3, which is structurally the closest to TRP7 in the TRP family. TRP7 induced Ca(2+) influx in response to ATP receptor stimulation at ATP concentrations lower than those necessary for activation of TRP3 and for Ca(2+) release from the intracellular store, which suggests that the TRP7 channel is activated independently of Ca(2+) release. In fact, TRP7 expression did not affect capacitative Ca(2+) entry induced by thapsigargin, whereas TRP7 greatly potentiated Mn(2+) influx induced by diacylglycerols without involvement of protein kinase C. Nystatin-perforated and conventional whole-cell patch clamp recordings from TRP7-expressing cells demonstrated the constitutively activated and ATP-enhanced inward cation currents, both of which were initially blocked and then subsequently facilitated by extracellular Ca(2+) at a physiological concentration. Impairment of TRP7 currents by internal perfusion of the Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid revealed an essential role of intracellular Ca(2+) in activation of TRP7, and their potent activation by the diacylglycerol analogue suggests that the TRP7 channel is a new member of diacylglycerol-activated cation channels. Relative permeabilities indicate that TRP7 is slightly selective to divalent cations. Thus, our findings reveal an interesting correspondence of TRP7 to the background and receptor stimulation-induced cation currents in various native systems.

Amino Acid Sequence↗
PubMed1999

Acoustic effects in chromatography.

An acoustic field effectively affects chromatographic retention in some separation modes and, thus can be a novel factor controlling retention. After being transmitted into the column, ultrasound energy is mostly converted into heat as a result of absorption by stationary and mobile phases. Thus, ultrasound brings about temperature increases. However, actual temperature increases measured by thermosensors are smaller than those calculated from chromatographic retention changes. In addition, larger ultrasound effects are observed in chromatographic modes involving ionic interactions. These results possibly imply that ultrasound directly influences ionic interactions involved in retention mechanisms.

Chromatography↗
PubMed1999

Interpretation of chromatographic behavior of ions based on the electric double-layer theory.

A retention model based on electrostatic theories is applied to the analysis of the ion-exchange chromatographic separation of ions. The adsorption of counterions and the ion-pair formation between ion-exchange sites and counterions are included in the model; these represent separation selectivity. A nonstoichiometric contribution, the accumulation of ions in an electrical double layer, is also involved in the model. The retention of ions is calculated by assuming these ionic properties for both eluent and solute ions. The comparison of calculated retention factors with experimental values gives insight into the ion-exchange nature of ions; e.g. a strongly adsorbed ion should have higher ion-pair formation ability, and vice versa.

Chromatography, Ion Exchange↗
PubMed1999

The protective immune response of yellowtail Seriola quinqueradiata to the bacterial fish pathogen Lactococcus garvieae.

Yellowtail Seriola quinqueradiata were immunized with 2 different Lactococcus garvieae bacterin, formalin-killed KG- phenotype cells (capsulated phenotype) and formalin-killed KG+ phenotype cells (unencapsulated phenotype). These 2 injected vaccines conferred long-term protection to yellowtail against an artificial infection of an encapsulated Lactococcus garvieae strain with long-lasting agglutinating titres against KG+ phenotype cells. However, no agglutinating titres or low agglutinating titres against KG- phenotype cells were detected in fish given each of these bacterin. These results suggested that a capsule in KG- phenotype cells apparently affects their immunogenicity, but the antigens which conferred protection to fish against lactococcal infection may be located on the surface of KG+ phenotype cells, and are not cell capsules in KG- phenotype cells. The protection offered by a formalin-killed KG+ phenotype cell vaccine would not appear to be strain specific. Encapsulated L. garvieae cells were well phagocytosed, and fimbrie-like appendages were seen in KG- phenotype cells after treatment with yellowtail immune serum.

Agglutination Tests↗
PubMed1999

1,3-Disubstituted benzazepines as novel, potent, selective neuropeptide Y Y1 receptor antagonists.

A novel series of potent and selective non-peptide neuropeptide Y (NPY) Y1 receptor antagonists, having benzazepine nuclei, have been designed, synthesized, and evaluated for activity. Chemical modification of the R(1) and R(3) substituents in structure 1 (Chart 1) yields several compounds that show high affinity for the Y1 receptor (K(i) values of less than 10 nM). SAR studies revealed that introduction of an isopropylurea group at R(1) and a 3-(benzo-condensed-urea) group, 3-(fluorophenylurea) group, or a 3-(N-(4-hydroxyphenyl)guanidine) group at R(3) in structure 1 afforded potent and subtype-selective NPY Y1 receptor antagonists. 3-(3-(Benzothiazol-6-yl)ureido)-1-N-(3-(N'-(3-isopropylureido++ +))benzyl )-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one (21), which was one of the most potent derivatives, competitively inhibited specific [(125)I]peptide YY (PYY) binding to Y1 receptors in human neuroblastoma SK-N-MC cells (K(i) = 5.1 nM). 21 not only inhibited the Y1 receptor-mediated increase in cytosolic free Ca(2+) concentration in SK-N-MC cells but also antagonized the Y1 receptor-mediated inhibitory effect of peptide YY on gastrin-induced histamine release in rat enterochromaffin-like cells. 21 showed no significant affinity in 17 receptor binding assays including Y2, Y4, and Y5 receptors.

Animals↗
PubMed1999

Young-Simpson syndrome: further delineation of a distinct syndrome with congenital hypothyroidism, congenital heart defects, facial dysmorphism, and mental retardation.

Young-Simpson syndrome is a rare congenital disorder, characterized by congenital hypothyroidism, congenital heart defects, facial dysmorphism, cryptorchidism in males, hypotonia, mental retardation, and postnatal growth retardation. We describe the cases of a 5-year-old boy and a 7-year-old girl with a similar constellation of symptoms and compared them with previously reported patients.

Brain↗
PubMed1999

Prediction of peptide retention times in normal-phase liquid chromatography with only a single gradient run.

Previous studies of peptide separation by normal-phase liquid chromatography have shown a linear relationship between the logarithm of the capacity factor and the logarithm of the volume fraction of modifier in the mobile phase. This permitted the use of a model to predict isocratic and gradient retention times based on data obtained by two initial gradient runs. In the present study, chromatographic behavior of 25 peptides in normal-phase liquid chromatography with isocratic elution have been studied and a linear relationship between the slope (S) and intercept [log k(0)] was obtained. This relationship was combined with the algorithm of prediction reported in the previous paper. The prediction of peptide retention times with only a single experimental gradient retention data was investigated.

Algorithms↗
PubMed1999

Activities of the primary and supplementary motor areas increase in preparation and execution of voluntary muscle relaxation: an event-related fMRI study.

Brain activity associated with voluntary muscle relaxation was examined by applying event-related functional magnetic resonance imaging (fMRI) technique, which enables us to observe change of fMRI signals associated with a single motor trial. The subject voluntarily relaxed or contracted the right upper limb muscles. Each motor mode had two conditions; one required joint movement, and the other did not. Five axial images covering the primary motor area (M1) and supplementary motor area (SMA) were obtained once every second, using an echoplanar 1.5 tesla MRI scanner. One session consisted of 60 dynamic scans (i.e., 60 sec). The subject performed a single motor trial (i.e., relaxation or contraction) during one session in his own time. Ten sessions were done for each task. During fMRI scanning, electromyogram (EMG) was monitored from the right forearm muscles to identify the motor onset. We calculated the correlation between the obtained fMRI signal and the expected hemodynamic response. The muscle relaxation showed transient signal increase time-locked to the EMG offset in the M1 contralateral to the movement and bilateral SMAs, where activation was observed also in the muscle contraction. Activated volume in both the rostral and caudal parts of SMA was significantly larger for the muscle relaxation than for the muscle contraction (p < 0.05). The results suggest that voluntary muscle relaxation occurs as a consequence of excitation of corticospinal projection neurons or intracortical inhibitory interneurons, or both, in the M1 and SMA, and both pre-SMA and SMA proper play an important role in motor inhibition.

Adult↗
PubMed1999

Peptide separation in normal-phase liquid chromatography. Study of selectivity and mobile phase effects on various columns.

An experimental procedure for peptide separation by normal-phase liquid chromatography (NPLC) was proposed in previous papers. In the present study, the chromatographic behavior of amino, cyano, amide, diol and silica columns, which have been used in non-aqueous NPLC, is investigated anew. The amino column was not appropriate for peptide separation because of poor recovery. The cyano column could not be used due to lack of retention. The amide, diol and silica columns were useful for peptide separation. The chromatograms on amide, diol and silica columns were a little different when the mobile phase composition was changed. The recovery of peptides was good: diol > amide > silica. Repeatability and reproducibility using amide, diol and silica columns was satisfactory.

Amides↗