Biomedical subjects

K Terada

Publications and source records attributed to K Terada.

At least 109 records · Page 6Linked to original sources

PubMed1998

Effect of exercise-induced activation of sympathetic nerve activity on clearance of 123I-MIBG from the myocardium.

The effect of exercise on the cardiac kinetics of 123I-MIBG was investigated in the present study. 123I-MIBG was administered intravenously at rest in 6 healthy male volunteers, and anterior planar and SPECT images were obtained 15 minutes, and 2 and 4 hours after administration (protocol A). After 4 weeks, 123I-MIBG was again administered intravenously at rest, and images were obtained 15 minutes later. After imaging, the subjects ran 10 km in approximately 1 hour, and anterior planar and SPECT images were obtained 2 and 4 hours after administration of 123I-MIBG (protocol B). The heart-to-mediastinum uptake ratio (H/M) was calculated from each anterior planar image, and the mean 123I-MIBG clearance from 15 minutes to 2 hours, and from 2 hours to 4 hours was calculated with a bull's eye display. The H/M was much lower after exercise. The mean clearance rate between 15 minutes and 2 hours in protocol B was significantly higher than that between 2 hours and 4 hours, and that between 15 minutes and 2 hours in protocol A. It was concluded that the clearance rate of 123I-MIBG may be a useful index of cardiac sympathetic nerve activity.

3-Iodobenzylguanidine↗

PubMed1998

Prediction of functional recovery and prognosis in patients with acute myocardial infarction by 123I-BMIPP and 201Tl myocardial single photon emission computed tomography: a multicenter trial.

123I-BMIPP [15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid] was developed for metabolic imaging with SPECT. A multicenter collaborative study was conducted on a large patient series to determine whether 123I-BMIPP and 201Tl myocardial SPECT are of use in predicting the prognosis and ventricular function after acute myocardial infarction (AMI). Patients with uncomplicated first AMI underwent resting 123I-BMIPP and 201Tl myocardial SPECT in the subacute phase after the onset of AMI. Of these, 167 patients who had been followed up for an average of 22 months were retrospectively reviewed to predict serious cardiac events and recurrent ischemia. In addition, the association between changes in radionuclide parameters and recurrent ischemia was investigated in Subgroup A (58 patients) who had repeated SPECT in the chronic phase. Furthermore, prediction of the ejection fraction (EF) was investigated in Subgroup B (94 patients) and Subgroup C (76 patients) in whom left ventriculography was performed at the time of discharge and 90 days or more after the onset, respectively. The prognosis was generally favorable, with 4 cases of cardiac death (2%), 3 of heart failure (2%), 4 of nonfatal reMI (2%), and 25 of recurrent ischemia (15%). The results of Cox multivariate regression analysis revealed a high probability of serious cardiac events in patients who were elderly (p = 0.04), who had 90% or more residual stenosis of the infarct-related artery (p = 0.09), and who had a high BMIPP defect score (p = 0.17). There was a high probability of recurrent ischemia in elderly patients (p = 0.10) who had multi-vessel disease (p = 0.03), but no association was found with radionuclide parameters in the subacute phase. In Subgroup A, however, the probability of recurrent ischemia tended to be high in patients with a large mismatch scorebetween 123I-BMIPP and 201Tl in the subacute to chronic phase. An important observation was that the extent of BMIPP defect was more strongly correlated with EF at the time of discharge and 90 days or more after the onset than the extent of Tl defect (r = -0.60 vs. r = -0.47, and r = -0.53 vs. r = -0.43, respectively). In addition, multiple regression analysis showed that parameters related to the BMIPP defect were also better predictive factors of EF both at the time of discharge and 90 days or more after the onset. In conclusion, resting 123I-BMIPP and 201Tl myocardial SPECT performed in the subacute phase of AMI were shown to be useful in predicting prognosis and ventricular function for patient management.

Aged↗

PubMed1998

Effects of diltiazem on myocardial perfusion abnormalities during exercise in patients with hypertrophic cardiomyopathy.

The effect of diltiazem on myocardial ischemia in patients with hypertrophic cardiomyopathy (HCM) was evaluated by exercise myocardial 201Tl single photon emission computed tomography (SPECT). Exercise myocardial SPECT was performed before and 8 weeks after oral administration of diltiazem (180 mg/day) in 20 patients with HCM who showed transient perfusion defects on exercise myocardial 201Tl SPECT under control conditions. SPECT images were divided into 17 segments. The 201Tl perfusion defects were visually scored and evaluated as the defect score. The transient dilation index was calculated as an index of subendocardial ischemia. Improvement of the defect score was demonstrated in 15 patients after the administration of diltiazem. The mean defect score decreased significantly from 9.90 +/- 5.17 to 5.50 +/- 4.89 (p < 0.0001). Although 16 of 20 patients showed an abnormal transient dilation index before diltiazem treatment, 16 showed improvement and 13 of these normalized after diltiazem therapy. The mean transient dilation index decreased from 1.16 +/- 0.10 to 1.02 +/- 0.09 (p < 0.0001). In conclusion, diltiazem prevents or diminishes myocardial ischemia in patients with HCM.

Adult↗

PubMed1998

Reappraisal of the effect of electrode property on recording slow potentials.

Subdural electrodes made of stainless steel, which were believed to be unsuitable for recording slow potentials, can still record Bereitschaftspotential (BP) (Neshige, R., Lüders, H. and Shibasaki, H. Recording of movement-related potentials from scalp and cortex in man. Brain, 1988, 11: 719-736) and ictal DC shifts (Ikeda, A., Terada, K., Mikuni, N., Burgess, R.C., Comair, Y., Taki, W., Hamano, T., Kimura, J., Lüders, H.O. and Shibasaki, H. Subdural recording of ictal DC shifts in neocortical seizures in humans. Epilepsia, 1996b, 37: 662-674) sufficiently. In this study, therefore, the effects of different kinds of metals on slow potential recordings were reevaluated. First, slow electro-oculograms (EOGs) were recorded with 3 different levels of input impedance (200 M omega, 470 k omega and 10 k omega) of a DC amplifier by using surface electrodes made of silver (Ag), silver/silver chloride (Ag/AgCl) and stainless steel. Secondly, BP was recorded by using the above electrodes with a long time constant of 3 s and with a fixed input impedance of 100 M omega. As a result: (1) slow EOGs were equally recorded with the input impedance of 200 M omega and 470 k omega regardless of the kind of metals used, although stainless steel electrodes caused baseline fluctuation, (2) low input impedance of 10 k omega allowed only the Ag/AgCl electrode to record slow EOGs without any decay, and (3) electrodes made of stainless steel could record BP as efficiently as the other two types of electrode with high input impedance. In conclusion, electrodes with a large surface area contact such as cup electrodes and an amplifier with a large input impedance, electrodes made of Ag, and even of stainless steel, can record slow potentials reasonably well.

Contingent Negative Variation↗

PubMed1998

ATP7B (WND) protein.

Wilson's disease is a genetic disorder of copper metabolism characterized by the excessive accumulation of this metal in the liver. The gene for Wilson's disease, designated ATP7B, encodes a copper transporting P-type ATPase expressed predominantly in the liver. Over 60 disease specific mutations of ATP7B have now been reported in patients with Wilson's disease. The gene for ATP7B is approximately 80 kb and contains 21 exons that encode an approximately 7.5 kb transcript. Recent studies that focus on the structure and expression of the ATP7B protein support its role as a copper transporter involved in the intracellular trafficking of copper in hepatocytes. The introduction of functional ATP7B protein by recombinant adenovirus mediated gene delivery will be a potential approach for correcting Wilson's disease.

Adenosine Triphosphatases↗

PubMed1998

Some relationships between the physical properties of various 3-acyloxymethyl prodrugs of phenytoin to structure: potential in vivo performance implications.

Physicochemical properties of neutral N-acyloxyalkyl derivatives of phenytoin in aqueous, organic solvents and simulated intestinal fluid were evaluated. Based on the hypothesis that these low melting prodrugs may have improved physical properties such as solubility and dissolution rate in gastrointestinal fluid, an enhanced bioavailability of these prodrugs may be observed relative to phenytoin. Melting points, aqueous solubilities, and octanol-water (Poct) and cylcohexane-water (Pcyc) partition coefficients of phenytoin and its prodrugs were determined. A simulated intestinal bile salts-lecithin mixture (SIBLM) was also prepared to possibly mimic the intestinal fluid content. Solubility and dissolution rates of phenytoin and its prodrugs were conducted in aqueous buffer and SIBLM. Apparent micelle-water partition coefficients (Kapp) were calculated by using the aqueous and SIBLM equilibrium solubility data. These properties were qualitatively or quantitatively correlated to the alkyl chain length of the prodrugs. The melting points and aqueous solubilities of all the prodrugs were lower than that of the parent compound, phenytoin. The apparent micelle-water partition coefficient increased with an increase in chain length but unlike the octanol-water and cyclohexane-water partition coefficients the relationship was complex. There was a disproportionate increase in the interaction between the micelle and the prodrug with the prodrugs with alkyl groups larger than four carbons. In SIBLM, the solubilities and dissolution rates were increased to a greater extent for the prodrugs than that for phenytoin. The implications are that the bioavailability of phenytoin from these prodrugs may be comparable to or higher than that of phenytoin despite having lower aqueous solubilities, especially after a meal inducing bile flow.

Bile Acids and Salts↗

PubMed1998

Low copy numbers of human T-cell lymphotropic virus type I (HTLV-I) tax-like DNA detected in the salivary gland of seronegative patients with Sjögren's syndrome in an HTLV-I endemic area.

To evaluate the hypothesis, proposed in previous reports from HTLV-I non-endemic areas, that HTLV-I is involved in a significant proportion, about a quarter, of Sjögren's syndrome patients who lack serum antibodies to the virus, we examined for the presence or absence of HTLV-I in DNA samples isolated from salivary gland tissues of 17 seronegative as well as 7 seropositive patients with Sjögren's syndrome in Nagasaki, Japan, where the virus is highly endemic. The nested two-step polymerase chain reaction (PCR), with a sensitivity capable of detecting a single DNA molecule, failed to amplify the HTLV-I tax sequence from DNA of 14 of the 17 seronegative patients. The tax was only amplifiable from the tissue DNA of the remaining three seronegative patients. The detection rate, 3/17 (18%), was, unexpectedly, less than those previously reported from the HTLV-I non-endemic areas. Moreover, in contrast to high viral loads (10(-1) to 10(-3) per cell) in the salivary gland of the seropositive patients, a semiquantitative PCR revealed that the copy number of the HTLV-I tax in the gland tissue of these seronegative patients was very low, 10(-5) per cell. This level is unlikely to be sufficient to promote an inflammatory reaction in the tissue. Our findings might argue against the involvement of "prototype" HTLV-I in the pathogenesis of Sjögren's syndrome in seronegative patients.

Adult↗

PubMed1998

Specific cellular immunity in immunocompetent children with herpes zoster.

We investigated whether specific immunity is low in immunocompetent children with zoster. Specific cellular immunity was found to be significantly lower in 13 otherwise normal children with zoster than it was in 8 matched controls by a lymphoproliferative assay. However, there was no significant difference between them with regard to the antibody response. Therefore, even in the immunocompetent children, decreased specific cellular immunity may play an important role in the mechanism of virus reactivation.

Antibodies, Viral↗

PubMed1998

Neural activation of the brain with hemodynamic insufficiency.

Little is known about how ischemia affects hemodynamic responses to neural activation in the brain. We compare the effects of a motor activation task and a cerebral vasodilating agent, acetazolamide (ACZ), on regional cerebral blood flow (rCBF) in primary sensorimotor cortex (PSM) in six patients with major cerebral artery steno-occlusive lesions without paresis of the upper extremities. Quantitative rCBF was measured in all patients using H2(15)O autoradiographic method and positron emission tomography. The CBF was determined at rest, during a bimanual motor activation task, and 10 minutes after ACZ administration. With bimanual motor activation, rCBF increased significantly in both PSM compared with at rest (P < 0.01 on lesion side, and P < 0.02 on contralateral side). However, rCBF did not increase after ACZ injection in the PSM on the lesion side, whereas rCBF increased significantly in the contralateral PSM after ACZ injection compared with the level at rest. This result suggests that despite a decreased hemodynamic reserve, there is a nearly normal flow response to neural activation, indicating that the mechanism of vasodilation responsible for perfusion change is different for acetazolamide and neural activation. The relations among neural activation, hemodynamic status, and cerebral metabolism in the ischemic stroke patients are discussed.

Acetazolamide↗

PubMed1998

Apoptosis of CD4+ T lymphocytes in human herpesvirus-6 infection.

The present authors have recently reported that inoculation with human herpesvirus-6 (HHV-6) renders CD4+ T lymphocytes susceptible to apoptosis in vitro. In order to confirm that apoptosis of CD4+ T lymphocytes also occurs in HHV-6 infection in vivo, apoptosis of lymphocytes isolated from nine patients with exanthem subitum and from an adult patient with severe HHV-6 infection was examined. Peripheral blood mononuclear cells were cultured for 3 days and apoptosis of lymphocytes was then examined by flow cytometry of propidium iodide-stained DNA. The percentages of hypodiploid DNA, indicating apoptosis, in lymphocytes from 10 patients with HHV-6 infection were significantly higher than those from five infant patients with noninfectious diseases and five healthy adults (P < 0-0002). DNA fragmentation was also detected by agarose gel electrophoresis in lymphocytes from patients with HHV-6 infection. Apoptosis appeared to occur predominantly in CD4+ T lymphocytes and HHV-6 was isolated from the CD4+ T lymphocyte fraction. These data demonstrate that HHV-6 renders CD4+ T lymphocytes susceptible to apoptosis in vivo.

Adult↗

PubMed1998

Prevention of N-methylnitrosourea-induced colon tumorigenesis by ursodeoxycholic acid in F344 rats.

Bile acids are known to promote colon carcinogenesis. However, there is one study showing that ursodeoxycholic acid (UDCA) supplemented in the diet at the concentration of 0.4% prevented azoxymethane-induced rat colon tumorigenesis. The aim of our study was to explore the inhibitory effect of a much smaller dose of UDCA on colon carcinogenesis in rats. One hundred 7-week-old F344 rats were given 2 mg of N-methylnitrosourea 3 times a week for 3 weeks by intrarectal instillation, and were fed a 0% (control), 0.4% or 0.08% UDCA-supplemented diet for the next 27 weeks. All the rats were killed and examined for tumor development at week 30. The tumor incidence and number were significantly lower and smaller, respectively, in the UDCA-fed rats than in the control rats: 40% and 36% vs. 68%; 0.5 +/- 0.1 (mean +/- SEM) and 0.4 +/- 0.1 vs. 1.0 +/- 0.2. All the tumors were located in the distal half of the colon and were plaque-shaped or polypoid, being well-differentiated adenocarcinomas restricted to the mucosa or submucosa. Bile acids in the feces and the blood obtained at weeks 20 and 30, respectively, were analyzed by HPLC. A significant increase of UDCA was confirmed in both the feces and the blood of the UDCA-fed rats compared with the control rats. The results suggest that the continuous feeding of a small dose of UDCA may prevent colon carcinogenesis.

Animals↗

PubMed1998

Clinical usefulness of the dipole tracing method for localizing interictal spikes in partial epilepsy.

PURPOSE: To clarify the clinical usefulness of the dipole tracing method in evaluation of interictal EEG spikes in patients with partial epilepsy. METHODS: Eight patients with partial epilepsy were studied. We compared the generator source of interictal spikes detected by the dipole tracing method with the results of magnetic resonance imaging (MRI), interictal/ictal measurement of cerebral blood flow (CBF) by single photon emission computed tomography (SPECT), interictal measurement of glucose metabolism by positron emission tomography (PET) and invasive electrocorticogram (ECoG). RESULTS: In 5 patients with mesial temporal lobe epilepsy (TLE), including 3 patients who underwent standard temporal lobectomy, the dipole tracing method showed results consistent with those of other examinations and better correlation with ECoG than with other noninvasive examinations. In a patient with mesial TLE who had defects in the skull due to previous surgery, the dipoles were located more laterally than expected. In a patient with frontal lobe epilepsy (FLE) who was finally proved to have an epileptogenic area in the lateral frontal area, the spike dipoles were identified in the medial side of the frontal lobe. CONCLUSIONS: The dipole tracing method used in the present study is useful for localizing epileptogenic areas in patients with mesial TLE. However, in patients with partial skull defects and in those with FLE, the reliability of this method is still in accuracy of the lobe level.

Adolescent↗

PubMed1998

[Possibility of prevention of herpes zoster by use of varicella vaccine].

It has been considered that a decline in specific cell-mediated immunity (CMI) for the varicella-zoster virus (VZV) could be responsible for a high incidence of herpes zoster in the elderly. If the strength of CMI for VZV could be increased by immunization of the elderly with a varicella vaccine, herpes zoster might be preventable. We compared the CMI for VZV (using a lymphoproliferative assay and a varicella skin test) and VZV-IgG antibodies in serum before and after 2-3 months of vaccination in 15 subjects more than 40 years old. When the CMI for VZV was measured by the lymphoproliferative assay, a stimulation index (SI) of more than 2.0 was estimated to be positive in this study. The SIs (mean +/- SD) before and after the vaccination were 2.7 +/- 1.8 and 2.7 +/- 1.9, respectively, and no significant difference was noted. On the other hand, the diameter of erythema in the varicella skin test after the vaccination became larger than that before the vaccination in the 10 of 13 subjects. In addition, serum VZV-IgG antibodies increased after vaccination in 6 of 14 subjects. There were no obvious reasons for the discrepancy in the results of the lymphoproliferative assay and the varicella skin test. However, because of the poor response indicated by the assay, only one vaccination for the elderly might not be enough to increase the CMI for VZV. The appropriate age for vaccination should also be considered. Lastly, further investigation of the CMI for VZV before and after vaccination on larger scale is required.

Aged↗

PubMed1998

The requirement of intercellular adhesion molecule-1 for neutrophil respiratory burst in the pulmonary circulation of rats infused with endotoxin.

Recently, we demonstrated direct evidence of respiratory burst of the neutrophil in the pulmonary circulation of the endotoxin-infused rat (Am. J. Respir. Crit. Care Med. 1995;152:348-354). To determine the role of intercellular adhesion molecule-1 (ICAM-1) in this model, we neutralized ICAM-1 using antirat ICAM-1 monoclonal antibody (mAb) 1A29. We observed and measured the number of sticking leukocytes and the amount of hydrogen peroxide (H2O2) in the pulmonary circulation of the endotoxin-infused rat by means of a fluoro-imaging technique. The rats received 4.5 mg/kg/h of endotoxin for 2 h. Ten rats received 2 mg/kg of mAb 1A29 20 min before the intravenous infusion of endotoxin. Although the pretreatment with mAb 1A29 did not reduce the number of leukocytes sticking to the pulmonary capillaries, it almost completely inhibited the H2O2 production of leukocytes in the rat lung infused with endotoxin. We confirmed that the leukocytes that produced H2O2 were neutrophil by an electron microscopic cerium technique. We conclude that, although ICAM-1 is not necessary for neutrophil to stick to the capillary in the rat pulmonary circulation infused with endotoxin, ICAM-1 is required for neutrophil H2O2 production in this model.

Animals↗

PubMed1998

Expression of vascular endothelial growth factor gene and its receptor (flt-1) gene in urinary bladder cancer.

We investigated expression of the vascular endothelial growth factor (VEGF) gene and its receptor gene (flt-1) in 30 patients with transitional cell carcinoma (TCC) of the urinary bladder by Northern blot hybridization analysis. The VEGF transcript was observed in all of the tumors and the normal mucosae. Of the 20 tumors in which a comparative study was done, eight (40.0%) overexpressed the gene with a tumor versus normal ratio of equal to and greater than 3.0. Invasive TCCs expressed significantly more VEGF gene than superficial TCCs. Cytoplasm of tumor cells was positively stained by immunohistochemistry with an anti-VEGF monoclonal antibody, while the intratumoral endothelial cells and the vascular smooth muscle cells were weakly positive for the staining. TCCs, normal mucosae and human umbilical endothelial cells expressed flt-1 gene, while leucocytes from peripheral blood did not. The expression level of flt-1 gene significantly correlated with that of the VEGF gene in the tumor. These results indicate that the VEGF gene is frequently overexpressed in TCC of the urinary bladder, especially in muscle invasive tumors, and that a paracrine system including VEGF and flt-1 exists between the TCC cells and the adjacent endothelial cells so as to regulate the angiogenesis in this tumor.

Adult↗

PubMed1998

Outcome after external decompression for massive cerebral infarction.

Acute ischemic stroke involving the entire vascular distribution of a carotid or middle cerebral artery can cause massive cerebral edema. This study evaluated external decompression for the treatment of massive stroke and analyzed possible prognostic factors. Twenty-four patients with acute massive cerebral infarction, which had progressed to tentorial herniation and impending death, underwent external decompression after medical therapy failed to achieve an effective response. The neurological outcome 2 months after surgery using the Glasgow Outcome Scale was severe disability in 14 patients, vegetative state in two, and death in eight. The overall mortality was 33%. Various characteristics (age, sex, etiology, side of hemispheric infarction, pupillary asymmetry, Japan Coma Scale, distribution of infarction, hemorrhagic infarction, midline shift, tentorial herniation) were evaluated to determine the factors associated with high mortality after surgical intervention. There was no statistically significant relationship between any variable and mortality. Mortality was especially high in the patients with preoperative consciousness level of 200, anterior, middle, and posterior cerebral artery territory infarction, and stage III of tentorial herniation. Postoperatively, all patients with severe disability returned to a clear level of consciousness. Six patients with dominant hemisphere stroke had some measure of communicative skills in spite of aphasia. External decompression is a life-saving treatment for patients with massive cerebral infarction and can provide a reasonable quality of life even for those with dominant hemisphere strokes. Decompressive surgery should be considered and performed as soon as possible if computed tomography demonstrates signs of descending tentorial herniation.

Acute Disease↗

PubMed1998

[A case of hypothalamic hamartoma manifesting gelastic seizure and multifocal independent seizure foci].

A 25-year-old man manifesting gelastic seizure in association with hypothalamic hamartoma was reported. The epileptogenic focus was evaluated by long-term video EEG monitoring, single photon emission computed tomography (SPECT) and positron emission tomography (PET). Multiple independent ictal foci were found in the ictal EEG recording, and glucose metabolism and cerebral blood flow were decreased in scattered cortical areas. Facial asymmetry seen during gelastic seizure in this case may be caused by contraction of mimetic contralateral to the ictal focus in the temporal lobe.

Adult↗

PubMed1998

Morphological comparison and functional reconstitution of rat hepatic parenchymal cells on various matrices.

Four types of materials, type I collagen coat (Coat), acid-soluble type I collagen gel (Hardgel), pepsin-treated acid-soluble type I collagen gel (Softgel), and an extract of extracellular matrix of the murine Engelbreth-Holm-Swarm sarcoma (Matrigel), were used as matrices to culture rat hepatic parenchymal cells, and their morphological changes and adhesion were compared to the matrices by electron microscopic observations. Hepatic parenchymal cells cultured on Coat and Hardgel were extended and flattened, whereas cells cultured on Softgel and Matrigel assembled and formed aggregates. Such aggregates consisted of several hepatic parenchymal cells, with a recognizable bile duct-like alveolus on the inside. Morphologically, the aggregates were more spherical on Matrigel and oval shaped on Softgel. Microvilli of the cell surface were parallel to the matrix on Matrigel, but invaded into the gel on Softgel. Subsequently, investigation into how these morphological features affected the liver-specific functions, including secretion of albumin and induction of P450 by 3-methylcholanthrene, demonstrated that a high level of liver function was maintained in a long-term culture in hepatic parenchymal cells on Softgel. These results suggest that hepatic parenchymal cell interactions were stronger with Softgel than with Matrigel, and that Softgel appears to closely mimic the in vivo environment.

Animals↗