Biomedical subjects

T Sugimoto

Publications and source records attributed to T Sugimoto.

At least 325 records · Page 18Linked to original sources

PubMed1998

Intraoperative map-guided operation for chronic atrial fibrillation.

Intraoperative map-guided cryoablation for chronic atrial fibrillation and coronary artery bypass grafting were simultaneously performed in a 55-year-old man. Computerized atrial mapping revealed that regular and repetitive electrical discharges originated in the left atrial appendage. Without opening the left atrium, we successfully ablated atrial fibrillation with cryoablation on the epicardium of the left atrial appendage. Thus, intraoperative mapping should facilitate operations for atrial fibrillation.

Atrial Fibrillation↗

PubMed1998

Influence of functional tricuspid regurgitation on right ventricular function.

BACKGROUND: Although right ventricular (RV) function has been extensively studied during the past decade, few reports have described the influence of functional tricuspid regurgitation (TR) on RV function. METHODS: One hundred forty-two patients with left-side valvular heart disease associated with TR were enrolled in the study and divided into three groups according to tricuspid annular diameter: group 1 (n = 66), tricuspid annular diameter less than 40 mm; group 2 (n = 58), tricuspid annular diameter of 40 to 50 mm; and group 3 (n = 18), tricuspid annular diameter greater than or equal to 50 mm. In groups 2 and 3, the right heart parameters had deteriorated to the point that TR repair was necessary. The mean follow-up period was 102 months after the operation. RESULTS: In each of the three groups, as pulmonary arteriolar resistance index increased, RV forward stroke work index increased in a linear fashion. The slope of the linear regression line was progressively less in group 1, 2, and 3 preoperatively. Postoperatively, this line moved in a parallel manner in group 1 and became steeper in group 2, consequently becoming similar in both groups. However, in group 3, although the slope became steeper in spite of a remarkable decrease of TR, it remained less when compared with groups 1 and 2. In addition, the right heart parameters also improved, but still remained worse in group 3 than group 2; 7 patients undergoing a flexible annuloplasty have shown gradual aggravations in TR and late postoperative clinical manifestations. CONCLUSIONS: Functional TR with severely dilated annulus may produce an irreversible deterioration of RV function. The preoperative relationship between pulmonary arteriolar resistance index and RV forward stroke work index, that is, RV systolic function to pressure afterload, might predict a postoperative fate of the right heart function.

Cardiac Catheterization↗

PubMed1998

NADPH-diaphorase activity in nerves and Schwann cells in the periodontal ligament of rat incisor teeth.

The lingual portion of the incisor periodontal ligament demonstrated activity for nicotinamide adenosine dinucleotide phosphate (NADPH)-diaphorase. Schwann cells surrounding Ruffini-like endings coexpressed NADPH-diaphorase activity and immunoreactivity for inducible nitric oxide synthase. NADPH-diaphorase-positive nerve fibres which coexpressed immunoreactivity for neuronal nitric oxide synthase were in contact with Schwann cells surrounding Ruffini-like endings or terminated as free nerve endings. Neural NADPH-diaphorase activity could not be found in the tissues covering the labial portion of incisor tooth root. It is possible that nitric oxide in Schwann cells and nerves has functions specific to the incisor periodontal ligament.

Animals↗

PubMed1998

Myoglobin mutants giving the largest geminate yield in CO rebinding in the nanosecond time domain.

We have measured the rebinding of carbon monoxide (CO) to some distal mutants of myoglobin (Mb) in the time range from 10(-8) to 10(-1) s by flash photolysis, in which the photodissociated CO rebinds to the heme iron without escaping to the solvent water from the protein matrix. We have found that the double mutants [His64-->Val/Val68-->Thr (H64V/V68T) and His64-->Val/Val68-->Ser (H64V/V68S)] have an extremely large geminate yield (70-80%) in water at 5 degreesC, in contrast to the 7% of the geminate yield of wild-type Mb. The CO geminate yields for these two mutants are the largest in those of Mb mutants reported so far, showing that the two mutants have a unique heme environment that favors CO geminate rebinding. Comparing the crystal structures and 1H-NMR and vibrational spectral data of H64V/V68T and H64V/V68S with those of other mutants, we discuss factors that may control the nanosecond geminate CO rebinding and CO migration in the protein matrix.

Carbon Monoxide↗

PubMed1998

Mass screening for neuroblastoma at 6 months of age: difficult to justify.

BACKGROUND/PURPOSE: A statistical analysis of the mass screening for neuroblastoma in Japan based on a population study rarely has been reported. This study aims to evaluate retrospectively the effectiveness of mass screening at 6 months of age using the available population data. METHODS: The data on the neuroblastoma cases registered by the Committee for Pediatric Solid Malignant Tumors in the Kyushu area were analyzed based on both screened and unscreened populations in the Kyushu area. RESULTS: From 1988 to 1992, the cumulative incidence of neuroblastoma in children less than 5 years of age was 82 in 484,599 for screened children, and 11 in 92,966 for unscreened children, respectively. Fourteen of the 82 screened patients had negative findings at 6 months of age (MS-negative cases). No significant difference was observed in the cumulative mortality rates from neuroblastoma in children younger than 5 years of age between the screened children and the unscreened children. Six of seven patients who died among the screened children were MS-negative cases with stage III or IV disease. In addition, no significant difference was found in the cumulative mortality rates from the neuroblastoma cases in patients less than 5 years of age between the children screened from 1988 to 1992 (7 of 484,599) and all children from 1980 to 1984 (14 of 668,084). CONCLUSIONS: These findings suggests that the majority of the patients detected by mass screening had a favorable prognosis, and, mass screening in Japan for children less than 6 months of age was not observed to reduce the incidence and mortality from neuroblastoma. Therefore, mass screening at 6 months of age was not found to improve substantially the prognosis of patients with unfavorable neuroblastoma identified over 1 year of age, which is the primary purpose of such mass screening for neuroblastoma.

Evaluation Studies as Topic↗

PubMed1998

A mixture of synthetic oligonucleotide probes labeled with biotin for the sensitive detection of potato spindle tuber viroid.

Five kinds of synthetic oligonucleotide probes labeled with biotin (BIO) were designed for the detection of potato spindle tuber viroid (PSTVd), and their sensitivities were compared with that of a digoxigenin (DIG)- or BIO-labeled cDNA probe. Although each oligonucleotide probe alone was less sensitive than the DIG-cDNA probe, sensitivity was increased by using a mixture of two or all of the five oligonucleotide probes. The sensitivity of a PSmix1-5 probe, which was a mixture of five oligonucleotides, was the same as that of a DIG-labeled cDNA probe, which can detect 7.8 pg of purified PSTVd and PSTVd in nucleic acids, equivalent to extracts from 20 microg of infected potato leaf and 310 microg of infected potato tuber. Using the PSmix1-5 probe, PSTVd in all leaves and tubers of seven potato cultivars could be detected without any background. Moreover, with the PSmix1-5 probe, the hybridization time could be shortened to 2 h without any decrease in sensitivity, whereas the sensitivity of the cDNA probes clearly decreased when the hybridization time was shortened. Hybridization using a mixture of several oligonucleotide probes may be applicable to the gene diagnosis of other viroids and viruses.

Base Sequence↗

PubMed1998

Crossing inputs of the superior laryngeal nerve afferents to medullary swallowing-related neurons in the cat.

To understand the neural mechanism for generation of synchronous activity on both sides during swallowing, we examined the convergence of inputs from the bilateral superior laryngeal nerves (SLNs) in the urethane-anesthetized cat medulla and we also examined the changes in swallowing outputs after a longitudinal brain-stem split in decerebrate cats. Twenty-six (31%) of 84 swallowing-related neurons (SRNs) that were oligosynaptically activated by ipsilateral SLN stimulation and recorded mostly in the reticular formation received contralateral inputs, which were confirmed by orthodromic spike responses (n = 16) or were detected as subliminal facilitatory or inhibitory inputs (n = 10) using conditioning-test stimuli. The rate of convergence of inputs from bilateral SLNs in these SRNs was significantly higher than that (4%) in the SRNs that were regarded as sensory-relay neurons in the nucleus tractus solitarius (NTS). The SRNs receiving signals from the contralateral SLN were located diffusely from the NTS and the adjacent reticular formation to the nucleus ambiguus (NA) and the reticular formation dorso-medial to the NA. A midsagittal split from 3 mm caudal to 6 mm rostral to the obex could change symmetrical swallowing to unilateral swallowing. Thus the crossing projections to the contralateral SRNs appear to contribute to symmetrical swallowing.

Afferent Pathways↗

PubMed1998

Post-transplant diabetes with anti-glutamic acid decarboxylase antibody during tacrolimus therapy.

A 54-year-old man undergoing hemodialysis because of end-stage renal failure was transplanted with a cadaver kidney in November 1997. He had no history of diabetes. Tacrolimus was used as the primary immunosuppressant. Three weeks after transplantation, he developed insulin-requiring diabetes mellitus. Anti-glutamic acid decarboxylase antibody was not detected on the third post-operative day, but appeared 4 weeks after transplantation. The recipient had DNA haplotypes that indicated susceptibility to Type 1 diabetes in Japanese subjects. Immunosuppressive therapy was changed from tacrolimus to cyclosporin. Thereafter, titer of anti-glutamic acid decarboxylase antibody disappeared and the patient's insulin requirement was notably reduced. The mechanism underlying the development of diabetes in this case appears to be, in part, direct beta-cell toxicity due to tacrolimus therapy, resulting in secondary beta-cell autoimmunity. This case suggests that tacrolimus therapy after transplantation should be used with caution in patients with genetic susceptibility to Type 1 diabetes.

Antibodies↗

PubMed1998

Enzymes related to catecholamine biosynthesis in Tetrahymena pyriformis. Presence of GTP cyclohydrolase I.

We first identified GTP cyclohydrolase I activity (EC 3.5.4.16) in the ciliated protozoa, Tetrahymena pyriformis. The Vmax value of the enzyme in the cellular extract of T. pyriformis was 255 pmol mg-1 protein h-1. Michaelis-Menten kinetics indicated a positive cooperative binding of GTP to the enzyme. The GTP concentration producing half-maximal velocity was 0.8 mM. By high-performance liquid chromatography (HPLC) with fluorescence detection, a major peak corresponding to D-monapterin (2-amino-4-hydroxy-6-[(1'R,2'R)-1',2',3'-trihydroxypropyl]pteridin e, D-threo-neopterin) and minor peaks of D-erythro-neopterin and L-erythro-biopterin were found to be present in the cellular extract of Tetrahymena. Thus, it is strongly suggested that Tetrahymena converts GTP into unconjugated pteridine derivatives. In this study, dopamine was detected as the major catecholamine, while neither epinephrine nor norepinephrine was identified. Indeed, this protozoa was shown to possess the activity of a dopamine synthesizing enzyme, aromatic L-amino acid decarboxylase. On the other hand, activities of tyrosine hydroxylase or tyrosinase which converts tyrosine into dopa, the substrate of aromatic L-amino acid decarboxylase, could not be detected in this protozoa. Furthermore, neither dopamine beta-hydroxylase activity nor phenylethanolamine N-methyltransferase activity could be identified by the HPLC methods.

Amino Acid Sequence↗

PubMed1998

Foot venous pressure measurement for evaluation of lower limb venous insufficiency.

PURPOSE: Foot venous pressure measurement is considered to be useful for assessing lower limb venous insufficiency, because venous hypertension is the main factor predisposing to venous insufficiency. In this study, we investigated the utility of foot venous pressure measurement in the evaluation of venous insufficiency. METHODS: A total of 148 limbs of 101 patients with venous insufficiency associated with varicose veins and treated over 5 years were studied. The measurements assessed were percentage decrease in foot venous pressure with manual calf compression (%drop), rate of increase in foot venous pressure during a 4-second period after release of compression (4SR%), and time to 50% recovery of foot venous pressure (RT50). RESULTS: A higher incidence of skin changes (clinical, etiologic, anatomic, and pathophysiologic classification classes 4 to 6) caused by venous insufficiency was associated with %drop, 4SR%, and RT50 values. Skin changes were found in more than 50% of the limbs with a %drop less than 50%, 4SR% more than 50%, or RT50 less than 4 seconds. After tourniquets were applied to occlude the superficial veins, limbs with severe below-knee deep venous reflux (%drop 60.3 +/- 14.6, 4SR% 36.7 +/- 30.2, RT50 13.9 +/- 14.7) showed significantly worse values than those with no reflux (%drop 79.9 +/- 3.2, 4SR% 8.1 +/- 3.1, RT50 48.9 +/- 17.9) or with mild above-knee reflux (%drop 77.0 +/- 5.0, 4SR% 7.1 +/- 3.2, RT50 46.9 +/- 26.7). After sclerotherapy or surgical treatment, including deep venous reconstruction for severe below-knee reflux, all limbs showed significant improvement in clinical manifestations and foot venous pressure values (%drop 68.1 +/- 7.5 to 76.5 +/- 5.8, 4SR% 33.1 +/- 12.9 to 12.7 +/- 7.6, RT50 7.5 +/- 4.2 to 20.1 +/- 6.5). CONCLUSION: Foot venous pressure measurements showed a good correlation with clinical severity and degree of venous reflux and were very useful for evaluating the outcome of therapy for venous insufficiency.

Adult↗

PubMed1998

Surgical treatment for transvenous tumor extension into the heart: four cases.

From 1984 to 1996, four patients with transvenous intracardiac tumor extension underwent operations in the Kobe University Hospital. The primary tumors of two were intravenous leiomyomatoses originating from the uterus; a third patient had invasive thymoma, and the fourth patient had clear cell sarcoma of the kidney. In 1985, one patient had a curative, staged resection. One-stage operations were carried out in three patients, and all intracardiac tumors were successfully resected en bloc with the primary tumors under conditions of electrical ventricular fibrillation and mild hypothermia. Combined venous reconstructions were necessary for en bloc resection in three cases. Two patients with malignancy received postoperative chemoradiotherapy, and all four patients were discharged uneventfully from our hospital. We consider radical resection with curative intent only for patients with tumors extending into the heart. In these cases, a one-stage operation is preferable, and electrical ventricular fibrillation with mild hypothermia is a recommended method of circulatory assist because of its simplicity.

Adult↗

PubMed1998

Radiographic and morphologic studies of multiple miliary osteomas of cadaver skin.

OBJECTIVES: The purpose of this study was to examine the frequency, chemical composition, and radiographic and morphologic features of multiple miliary osteomas of the facial skin. STUDY DESIGN: Facial skin was obtained from 33 cadavers. After contact radiographs were taken, osteomas were examined by photo and scanning electron microscopy. Radiographic microanalysis of inorganic elements of the osteomas was also performed. In addition, clinical dental radiographic examinations were performed on 158 living subjects. RESULTS: Radiographic examination revealed milia-like osteomas in the facial skin of all of the cadavers. Nodules of 0.5 to 2.0 mm in diameter were scattered symmetrically in the skin of the cheek, mandibular angle, and forehead. Each nodule consisted of a concentric, multilamellated, osteoid cortex and an adipose medulla. Microanalysis suggested the presence of hydroxyapatite similar in composition to that of normal cortical bone. The condition was detected in 28% (44/158) of the living subjects by clinical dental radiographic examination. CONCLUSION: Multiple miliary osteoma is a very common condition and may not be related to specific diseases.

Adipose Tissue↗

PubMed1998

Physiological levels of C-reactive protein in normal canine sera.

This study was undertaken to investigate whether the level of C-reactive protein (CRP) in the serum of dogs undergoes physiological variation, using 10 normal Beagle dogs (5 males and 5 females), 1-2 years old, maintained in a healthy condition in a controlled environment. The CRP concentration in the sera collected seven times each day at intervals of approximately 3 h ranged from 0.8 to 16.4 micrograms/ml (mean 5.06 +/- 3.60) in one experiment and from 0.8 to 14.0 micrograms/ml (mean 4.50 +/- 2.80) in a second experiment. On examining the 24-h variations in the concentration of CRP in serum, neither consistent changes nor a definite pattern of circadian rhythm was detected. During 28 days observation, only very slight changes, which seemed attributable to analytical errors, were seen in any of the dogs, except one. The concentration of CRP in the serum during the 28 days ranged from 0.8 to 22.6 micrograms/ml (mean 3.65 +/- 1.40). The concentrations underwent no significant variations in individual dogs, but significant differences were found between the dogs (p < 0.01).

Animals↗

PubMed1998

Impaired motor coordination in mice lacking prion protein.

1. Prion protein (PrPC) is a host-encoded glycoprotein constitutively expressed on the neuronal cell surface. Accumulation of its protease-resistant isoform is closely related to pathologic changes and prion propagation in the brain tissue of a series of prion diseases. However, the physiological role of PrPC remains to be elucidated. 2. After long-term observation, we noted impaired motor coordination and loss of cerebellar Purkinje cells in the aged mice homozygous for a disrupted PrP gene, a finding which strongly suggests that PrPC plays a role in the long-term survival of Purkinje cells. 3. We also describe the resistance of the PrP null mice to the prion, indicating the requirement of PrPC for both the development of prion diseases and the prion propagation.

Animals↗

PubMed1998

Pharmacological characterization of the human vasopressin receptor subtypes stably expressed in Chinese hamster ovary cells.

Three subtypes of human (h) arginine vasopressin (AVP) receptors, hV1A, hV1B and hV2, were stably expressed in Chinese hamster ovary (CHO) cells and characterized by [3H]-AVP binding studies. In addition, the coupling of the expressed receptor protein to a variety of signal transduction pathways was investigated. Scatchard analysis of saturation isotherms for the specific binding of [3H]-AVP to membranes, prepared from CHO cells transfected with hV1A, hV1B and hV2 receptors, yielded an apparent equilibrium dissociation constant (Kd) of 0.39, 0.25 and 1.21 nM and a maximum receptor density (Bmax) of 1580 fmol mg(-1) protein, 5230 fmol mg(-1) protein and 7020 fmol mg(-1) protein, respectively. Hill coefficients did not differ significantly from unity, suggesting binding to homogenous, non-interacting receptor populations. Pharmacological characterization of the transfected human AVP receptors was undertaken by measuring the relative ability of nonpeptide AVP receptor antagonists, YM087, OPC-21268, OPC-31260, SR 49059 and SR 121463A, to inhibit binding of [3H]-AVP. At hV1A receptors, the relative order of potency was SR49059>YM087>OPC-31260>SR 121463A> >OPC-21268 and at hV2 receptors, YM087=SR 121463A>OPC-31260>SR 49059> >OPC-21268. In contrast, the relative order of potency, at hV1B receptors, was SR 49059> >SR 121463A=YM087=OPC-31260=OPC-21268. In CHO cells expressing either hV1A or hV1B receptors, AVP caused a concentration-dependent increase in intracellular Ca2+ concentration ([Ca2+]i) with an EC50 value of 1.13 nM and 0.90 nM, respectively. In contrast, stimulation of CHO cells expressing hV2 receptors resulted in an accumulation of cyclic AMP with an EC50 value of 2.22 nM. The potency order of antagonists in inhibiting AVP-induced [Ca2+]i or cyclic AMP response was similar to that observed in radioligand binding assays. In conclusion, we have characterized the pharmacology of human cloned V1A, V1B and V2 receptors and used these to determine the affinity, selectivity and potency of nonpeptide AVP receptor antagonists. Thus they may prove to be a valuable tool in further examination of the physiological and pathophysiological roles of AVP.

Animals↗

PubMed1998

Antitumor effect of medium-chain triglyceride and its influence on the self-defense system of the body.

Medium-chain triglyceride (MCT), long-chain triglyceride (LCT), and their mixture were compared in reference to both cytotoxic effect against human tumor cells and influence on the immune system. MCT showed more potent cytotoxicity than LCT. Continuous contact with MCT also inhibited the cytotoxic effect of lymphokine-activated killer (LAK) cells much more strongly than LCT. However, there is a discrepancy between the concentration of MCT, or the mixture, that could suppress the growth of tumor cells and the concentration that inhibited the cytotoxicity of LAK cells. Moreover, no damage was observed in PBL or LAK cells or in their cytotoxicity when the cells were incubated with TG for 2 h a day. Thus, short-term contact with TG could inhibit tumor growth while immune system was maintained within normal range. Clinically fine control of the concentration of injected triglycerides, especially MCT, can be expected to provide potent antitumor effect and maintenance of normal immune system.

Antineoplastic Agents↗

PubMed1998

S100 protein-immunoreactive trigeminal neurons innervating the rat molar tooth pulp.

S100-immunoreactivity (ir) was examined in tooth pulp primary neurons of the rat. An immunofluorescence method demonstrated that the molar tooth pulp contained S100-immunoreactive (ir) nerve fibers. In the root pulp, pulp horn and roof of the pulp chamber, S100-ir smooth and varicose fibers ramified and formed subodontoblastic nerve plexuses. All the fibers became varicose at the base of the odontoblastic layer and extended to the odontoblastic layer. Some varicose endings could be traced into the dentin. The trigeminal neurons retrogradely labeled with fluorogold (FG) from the first and second maxillary molar tooth pulps exhibited S100- and parvalbumin-ir. Approximately 60% and 24% of the labeled cells were ir for S100 and parvalbumin, respectively. Virtually all parvalbumin-ir FG-labeled cells showed S100-ir, while 40% of S100-ir ones coexpressed parvalbumin-ir. An immunoelectron microscopic method revealed that all myelinated axons and half of the unmyelinated axons in the root pulp contained S100-ir. In the odontoblastic layer, predentin and dentin, S100-ir neurites lost the Schwann cell ensheathment and made close contact with cell bodies and processes of odontoblasts. The odontoblastic layer also contained parvalbumin-ir neurites. These neurites were devoid of the Schwann cell ensheathment and in close apposition to cell bodies and processes of odontoblasts. S100-ir pulpal axons seemed to be insensitive to repeated neonatal capsaicin treatment. This study suggests that S100-ir tooth pulp primary neurons are mostly myelinated and that S100-ir unmyelinated axons in the root pulp are preterminal segments of myelinated stem axons.

Animals↗

PubMed1998

Identification of an enhancer sequence in 5'-flanking region of 1A exon of mouse liver/bone/kidney-type alkaline phosphatase gene.

The 5'-flanking region of the 1A exon of the mouse liver/bone/kidney-type alkaline phosphatase (L/B/K ALP) gene was analyzed for the promoter activity. Luciferase assays revealed that a segment containing a 9 bp inverted repeat (nt -1212 to -1179, designated as IRS for inverted repeat segment) had an enhancer activity. Though an E-box at nt -234 did not have a prominent promoter activity, the effect of IRS required its presence. Both transcriptional activity and IRS binding to the nuclear proteins were similarly observed even in cells that did not express ALP. Bone morphogenetic protein-2 (BMP-2) induced the ALP expression in pluripotent C3H10T1/2 cells, but it did not increase the transcriptional activity of the promoter region. Though they do not determine cell specific or BMP-2 inducible ALP expression, IRS and the E-box at position -241 seem to be important for the basic transcriptional activity of ALP gene.

3T3 Cells↗