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Biomedical subjects

K Terada

Publications and source records attributed to K Terada.

At least 163 records · Page 9Linked to original sources
PubMed1996

Selective Isolation of DNA or RNA Using Single-Stranded DNA Affinity Latex Particles.

We developed latex particles with a diameter of about 0.22 µm on which single-stranded (ss) DNA was covalently coupled to select or enrich its complementary DNA or mRNA. DNA was first covalently coupled to the latex particles in the double-stranded (ds) form with both blunt and protruding ends. More than 80% of the dsDNA was coupled through the ssDNA stretch at its protruding end. The presence of NaCl in the immobilization reaction severely inhibited DNA from coupling to the particles. The particles were then treated with alkali or heated to denature the dsDNA and sedimented by a brief centrifugation to yield ssDNA immobilized particles. They allowed the selective and efficient isolation of a desired RNA from total cellular RNA.

Journal Article↗
PubMed1996

Abnormal sensorimotor integration in writer's cramp: study of contingent negative variation.

To investigate the pathophysiology of idiopathic focal dystonia, we recorded contingent negative variation (CNV) as a physiological index of sensorimotor integration in 14 right-handed patients with writer's cramp and compared it with normative data. CNV was recorded in the S2 choice reaction time paradigm: Two kinds of auditory S2 (Go or No-Go) were given 2 s after the auditory S1, and the subject reacted only to the Go signal by extending the wrist. In normal subjects, the late CNV amplitude had no difference at Cz between left- and right-hand tasks and was symmetric without significant amplitude laterality irrespective of the side of hand movement. In patients with writer's cramp, the late CNV amplitude at Cz was relatively larger for the left-hand task than the right-hand task (p < 0.03), and a significant amplitude laterality of the late CNV (larger on the right) was present especially at the central area for the right-hand task (p < 0.03). Since the late CNV is known to be generated, at least in part, from primary and supplementary motor cortices, the significant laterality of the late CNV seen with the right-hand task in patients with writer's cramp might represent functional abnormality of motor cortices possibly as the result of basal ganglia function.

Adult↗
PubMed1996

Somatosensory evoked potentials following proprioceptive stimulation of finger in man.

Brisk passive flexion of the proximal interphalangeal joint of the middle finger, produced by using a newly devised instrument, elicited evoked potentials on the scalp. The present study carefully excluded the possible contribution of sensory modalities other than proprioception. The initial part of cortical response was a positive deflexion at the contralateral central area (P1 at 34.6 ms after the stimulus). This was followed by a midfrontal negative wave (N1 at 44.8 ms) and a clear positivity at the contralateral centroparietal area (P2 at 48.0 ms). The evoked responses persisted in spite of the abolition of cutaneous and joint afferents of the finger caused by ischemic anesthesia, but they were lost by ischemic anesthesia of the forearm. Thus, the cortical evoked responses obtained in this study most probably reflect muscle afferent inputs. The scalp distribution of P1 suggested that its cortical generator source was different from that of the N20-P20 components of evoked potentials to electrical median nerve stimulation. Brodmann areas 2 and 3a of human brain, which are known to receive deep receptor inputs, are the most plausible generator sites for the early components of the proprioception-related evoked responses. The amplitude of P2 was related to the velocity but not to the magnitude of movement. In conclusion, the present study established a method for recording the evoked responses to the brisk passive movement of the finger joint, which mainly reflect the dynamic aspects of proprioception mediated through muscle afferent.

Adult↗
PubMed1996

Investigation of the relationship between regression of hypertensive cardiac hypertrophy and improvement of cardiac sympathetic nervous dysfunction using iodine-123 metaiodobenzylguanidine myocardial imaging.

Although many theories exist on the subject, the mechanisms responsible for a reduction of hypertensive cardiac hypertrophy in response to antihypertensive therapy are still unclear. In order to investigate the relationship between regression of hypertensive cardiac hypertrophy and cardiac nervous function, we studied ten patients with untreated essential hypertension (six men and four women, 62+/-12 years old). Both echocardiography and iodine-123 metaiodobenzylguanidine (MIBG) myocardial imaging were performed before and after antihypertensive therapy. Left ventricular mass (LVM) was significantly reduced in conjunction with the reduction of blood pressure following treatment. MIBG myocardial images showed that the heart-to-mediastinum activity ratio (H/M) was significantly increased while the washout ratio was significantly decreased. Patients were divided into two groups according to the ratio of the LVM values before and after therapy (LVM ratio). Patients with an LVM ratio of less than 0.75 were classified as group A and those with values higher than 0.75 as group B. Neither the change in blood pressure nor the length of treatment was significantly different between these two groups. On the other hand, both the increase in H/M and the decrease in the washout ratio were significantly greater in group A than in group B. These results indicate that an improvement in cardiac sympathetic nervous function may be related to the regression of hypertensive cardiac hypertrophy. Increasing the subject base in these studies and a more precise analysis of the relevance of the data obtained from MIBG myocardial images are recommended to clarify how changes in cardiac sympathetic nervous function relate to the regression of hypertensive cardiac hypertrophy.

3-Iodobenzylguanidine↗
PubMed1996

Alteration of T cells and natural killer cells during chickenpox in infancy.

To determine the reasons for the low immune response and the mild morbidity of chickenpox in infancy, we investigated alteration of T cells and natural killer (NK) cells during chickenpox in children < 1 year and > or = 2 years old using flow cytometry. The CD4/CD8 ratio decreased only in the < 1-year-old group from the acute to the convalescent phase (P < 0.05). The CD3-CD16+CD56+ and CD57-CD16+ counts increased in the < 1-year-old group, but those in the > or = 2-year-old group did not increase from the acute to the convalescent phase. The CD3-CD16+CD56+ counts and the CD57-CD16+ counts and percentage were larger in the < 1-year-old group than those in the > or = 2-year-old group (P = 0.001, P = 0.002, and P < 0.05) in the convalescent phase. These results seem to indicate that the low immune response in infancy after chickenpox are related to the small number of CD8 in contrast with CD4 and that increased subsets of NK cells during chickenpox may correlate to the mild morbidity of chickenpox in infancy.

Acute Disease↗
PubMed1996

Optimal beam quality for chest computed radiography.

RATIONALE AND OBJECTIVES: Optimal x-ray beam quality for chest computed radiography (CR) has not been determined. To investigate the optimal beam quality for chest CR, the authors measured the radiographic contrasts and compared the image quality of chest CR and screen-film (SF) radiographs using various x-ray tube voltages. METHODS: Chest CR and SF radiographs were obtained on a phantom lung and human volunteers with or without a variety of simulated lung opacities using various x-ray tube voltage levels. Exposures were set to maintain identical patient exposure doses for all images. The contrast between peripheral lung and rib or heart was measured on these images and the differences were compared. The quality of the images of each simulated opacity was evaluated by five radiologists using a five-point grading scale. RESULTS: Contrast between peripheral lung and rib or heart increased on CR images obtained by lowering the tube voltage from 140 to 80 kV, but the degree of increase was less than half the increase on SF images. The CR images of the simulated opacities obtained using a lower tube voltage were judged to be superior to those obtained with a higher tube voltage. Scattered radiation was reduced on CR images with a lower tube voltage. CONCLUSION: The image quality of chest CR was improved by using a lower tube voltage than that used for conventional SF chest radiography. Considering the problem of tube loading in clinical applications, a tube voltage of 100 kV is recommended for chest CR.

Evaluation Studies as Topic↗
PubMed1996

Immunogenicity of the whole antigen and glycoprotein I of varicella-zoster virus (VZV) and the VZV skin test antigen.

Specific cellular immunity against the whole antigen and glycoprotein I (gp I) of varicella-zoster virus (VZV) and the skin test antigen were determined for 13 healthy immune adults to compare the immunogenicity of these antigens using a lymphoproliferative assay. The stimulation index values (mean +/- s.d.) were 16.4 +/- 11.2 against the whole VZV antigen, 4.2 +/- 2.9 against the VZV skin test antigen and 1.1 +/- 0.5 against gp I. The immunogenicity of the skin test antigen, which mainly contains gp III and gp IV, appears to be more favorable than that of gp I alone, but to be weaker than that of the whole VZV antigen.

Adult↗
PubMed1996

Subdural recording of ictal DC shifts in neocortical seizures in humans.

PURPOSE: Invasive ictal EEG recording is often necessary to delineate epileptogenic areas in patients with intractable partial epilepsy, but even intracranial ictal recordings often reveal ill-defined onset zones in neocortical epilepsy. We studied the physiologic significance of ictal direct current (DC) potentials recorded intracranially in human epilepsy. METHODS: We made intracranial ictal EEG recordings in three patients with intractable partial seizures arising from frontal, lateral temporal, and parietal neocortical areas by using closely spaced subdural electrodes (platinum in two patients and stainless steel in one patient) with both standard (1.5 Hz) and open (0.016 Hz) low-frequency filter (LFF) settings. RESULTS: The initial ictal pattern was localized to two to nine subdural electrodes and characterized by very low voltage and high-frequency rhythmic activity ("electrodecremental pattern"). A slow-rising negative potential (DC potential) was seen in a slightly more restricted area (two to six electrodes) and occurred 1-10 s before the initial ictal EEG discharges in two patients. CONCLUSIONS: These results agree with those of previous studies of ictal DC shifts in animals and suggest that ictal DC shifts may be helpful in delineating the epileptogenic area more precisely in human epilepsy.

Adolescent↗
PubMed1996

[Double infection of Chlamydia pneumoniae and Mycoplasma pneumoniae in children].

There have been fewer reports on Chlamydia pneumoniae infection during childhood than those in adults, although many of the C. pneumoniae infections occurred during childhood based on prevalence of the antibody. And there have been no reports concerning the double infection of C. pneumoniae and M. pneumoniae. We reported three cases of children with the double infection. We diagnosed this from significant alteration of these antibodies from the acute to convalescent phases. We omitted the cases without significant alteration of the antibodies, even diagnosed from isolation or detection of the antigens in the samples by direct fluorescent antibody. Case 1 was an 8-year-old-boy who was admitted to our hospital because of fever, cough with vomiting and erythema multiforme. The symptoms did not subside after administration of clindamycin but subsided after minocycline. Case 2 was an 1-year-old-boy who was admitted because of fever, cough, rhinorrhea and vomiting. C. pneumoniae organisms were isolated from the pharyngeal swab specimen, the symptoms subsided after administration of clindamycin. Case 3 was a 9-year-old boy who was admitted because of fever and a cough followed by erythema multiforme. The symptoms did not decrease after administration of clindamycin but after minocycline. The characteristic of these cases are a strong cough with vomiting, weak response of acute reactants on the laboratory data, and skin eruption similar with that due to M. mycoplasmae in two of the three cases. We suspect that these double infections may induce the eruption, about which there have been no previous reports.

Child↗
PubMed1996

[A case with petechiae due to human parvovirus B19].

We reported a case of 10-year-old girl with petechiae mainly on the truncus, although who had more than 10 x 10(4)/microliter of platelets. Smears of her bone marrow demonstrated extreme reduction of erythroblasts with giant proerythroblast like cells, which does not consist with idiopathic thrombocytopenic purpura. Human parvovirus B19 (B19) DNA was detected in her serum and throat swab using PCR and significant alterations of B19 specific IgM and IgG antibody titers were demonstrated. The petechiae subsided on the 8th day after her admission. She had not shown anemia less than Hb 10 g/dl, but her reticulocytes counts had increased up to 3.5% on the 11th day after her admission. Smears of her bone marrow on the 17th day became normal with moderate erythroblasts. It is demonstrated that the cellular receptor of this virus is an antigen of the blood group P recently. P antigen is presented not only on erythrocytes and on erythroblasts but also on megakaryocytes and endotherial cells. Therefore, it is suggested that direct injury by B19 to endothelial cells could cause petechiae in this case.

Child↗
PubMed1996

The requirement of heat shock cognate 70 protein for mitochondrial import varies among precursor proteins and depends on precursor length.

The cytosolic heat shock cognate 70-kDa protein (hsc70) is required for efficient import of ornithine transcarbamylase precursor (pOTC) into rat liver mitochondria (K. Terada, K. Ohtsuka, N. Imamoto, Y. Yoneda, and M. Mori, Mol. Cell. Biol. 15:3708-3713, 1995). The requirement of hsc70 for mitochondrial import of various precursor proteins and truncated pOTCs was studied by using an in vitro translation import system in which hsc70 was completely depleted. hsc70-dependent import of pOTC was about 60% of the total import, while import of the aspartate aminotransferase precursor, the serine:pyruvate aminotransferase precursor, and 3-oxoacyl coenzyme A thiolase was about 50, 30, and 0%, respectively. The subunit sizes of these four precursor proteins were 40 to 47 kDa. When pOTC was serially truncated from the COOH terminal, the hsc70 requirement decreased gradually and was not evident for the shortest truncated pOTCs of 90 and 72 residues. These truncated pOTCs were imported and proteolytically processed rapidly in 0.5 to 2 min at 25 degrees C, and the processed mature portions and the presequence portion were rapidly degraded. Sucrose gradient centrifugation analysis followed by import assay showed that pOTC synthesized in rabbit reticulocyte lysate forms an import-competent complex of about 11S in an hsc70-dependent manner. S values of import-competent forms of aspartate aminotransferase precursor, serine:pyruvate aminotransferase precursor, and 3-oxoacyl coenzyme A thiolase were 9S, 9S, and 4S, respectively. Thus, the S value decreased as the hsc70 dependency decreased. Precursor proteins were coimmunoprecipitated from the reticulocyte lysate containing the newly synthesized precursor proteins with an hsc70 antibody. The amount of coimmunoprecipitated proteins was much larger in the absence of ATP than in its presence. Among the four precursor proteins, the amount of coimmunoprecipitated protein decreased as the hsc70 dependency decreased.

Acetyl-CoA C-Acyltransferase↗
PubMed1996

Biosynthesis of the acetylenic compounds in cultured cells of Asparagus officinalis from D- and 13C-labelled phenylalanines.

Studies on the biosynthetic pathway of acetylenic compounds, 4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]phenol and its related compounds, in cultured cells of Asparagus officinalis L. (Liliaceae) revealed that all of the 17 carbon atoms in their skeletons are supplied by phenylalanine. It is also concluded that p-substituted phenylacetylenic moieties (the C6-C2 unit) in these compounds are derived from C6-C3 shikimate pathway metabolites via phenylalanine. As a working hypothesis concerning the C6-O-C3 unit formation, a spirotetrahydrofuran type intermediate is predicted.

Acetylene↗
PubMed1996

[Development of new anti-cancer agents in Europe].

CPT-11 was synthesized 12 years after its mother compound, camptothecin, had been dropped from development by NCI (USA). A new drug application with CPT-11 was filed in 1991 after phase I and phase II clinical studies, and the marketing approval was authorized in 1994 with indications of non-small cell and small cell lung cancers, cervical cancers, and ovarian cancers. Phase I studies in France were initiated in 1990 one year after late phase II studies were started in Japan. A new drug application was filed in 1994 after phase II studies and marketing approval was authorized by the French government in May, 1995 with indication of advanced colon cancers. Clinical development of new anticancer agents in France was discussed.

Antineoplastic Agents↗
PubMed1996

[A case of intractable temporal lobe epilepsy: discrepancy between epileptogenic area and structural lesion demonstrated by subdural recording].

We reported a 25-year-old man with intractable right temporal lobe epilepsy in whom subdural recording successfully delineated the epileptogenic area in the right anterior mesial to basal temporal region in spite of the presence of a postoperative lesion in the right posterior temporal region. The patient underwent right posterior temporal resection due to ependymoma at the age of 8 years. Since age 19, he had suffered from medically intractable psychomotor seizures. Ictal scalp-recorded EEG suggested an epileptogenic area at the right temporal area, but it could not specifically demarcate the site because of bone deficits from the previous surgery. Ictal SPECT showed a hyperactive area in the right anterior temporal area, which was inconsistent with the MRI finding. In case of partial epilepsy associated with structural lesion like in the present case, if results of various non-invasive studies are discrepant as to the epileptogenic area, invasive studies using, for example, subdural EEG monitoring is necessary to determine the responsible area.

Adult↗
PubMed1996

[The serial change of the 123I-BMIPP SPECT in patients with hypertrophic cardiomyopathy].

We studied the serial change of 123I-BMIPP SPECT in the process of hypertrophic cardiomyopathy (HCM). In 16 patients with HCM, the imaging data were acquired 15 minutes after injection of 111 MBq 123I-BMIPP. The SPECT image was divided into 17 segments and the severity of the defect in each segment was scored visually using defect score, a 4-point grading system (score 0 = normal, score 1 = mildly decreased uptake, score 2 = moderately decreased uptake, score 3 = severely decreased uptake or defect). Each patient underwent this examination twice with interval of 25 +/- 14 months. In the first examination, we observed reduced uptake in 14 cases (88%), and often found it in septal portion of anterior or posterior wall. In the second examination, compared with the first study, total defect score (TDS: the summation of defect score of 17 segments) had increased in 7 cases (44%) of 16 cases, decreased in only 1 case (6%), and unchanged in 8 cases (50%). The regional defect score often increased in septal portion of anterior and posterior walls, and the high score area widespread toward the septum. There was no difference between TDS unchanged group and TDS worsened group in the point of background (age, family history of HCM), the interval of the two studies, and the findings of echocardiography (Dd, Ds, %F). In TDS worsened group (n = 7), clinically only 1 case became progressed stage. In others there were no progression in each clinical, echocardiographic, or 201Tl scintigraphic findings. This study revealed that myocardial fatty acid metabolic disorder often progresses during short interval in patients with HCM. In conclusion, the serial examination of 123I-BMIPP SPECT may contribute to an estimation of the stage or the prognosis in HCM.

Adult↗
PubMed1995

Ras is not required for the interleukin 3-induced proliferation of a mouse pro-B cell line, BaF3.

It has been demonstrated that Ras is involved in interleukin 3 (IL-3)-stimulated signal transduction in various hematopoietic cultured cells (Satoh, T., Nakafuku, M., Miyajima, A., and Kaziro, Y. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 3314-3318; Duronio, V., Welham, M. J., Abraham, S., Dryden, P., and Schrader, J. W. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 1587-1591). However, it has not been fully understood which of IL-3-promoted cellular responses, i.e. proliferation, survival, and differentiation, requires Ras function. We employed a system of inducible expression of the dominant-negative (S17N) or dominant-active (G12V) mutant of Ras in BaF3 mouse pro-B cell line to analyze the role of Ras in IL-3-stimulated signal transduction. Induction of the dominant-negative Ras(S17N) effectively inhibited the IL-3-induced activation of c-Raf-1 and mitogen-activated protein kinase (MAPK). Furthermore, the activation of fos gene promoter following IL-3 stimulation was almost completely abolished when Ras(S17N) was induced. Under these conditions, Ras(S17N) exhibited no inhibitory effect on IL-3-dependent proliferation assessed by the increase of cell numbers and a mitochondrial enzyme activity. The results indicate that Ras-dependent pathways, including the Raf/MAPK/Fos pathway, are dispensable for IL-3-induced growth stimulation. When BaF3 cells were treated with a tyrosine kinase inhibitor, herbimycin A, IL-3-dependent proliferation of the cells was impaired, suggesting that tyrosine kinase-mediated pathways are critical for growth promotion. On the other hand, apoptotic cell death caused by deprivation of IL-3 was prevented by the induction of the activated mutant Ras(G12V), although the rate of cell number increase was markedly reduced. Thus, it is likely that Ras-independent pathways play important roles to facilitate the proliferation although they may not be essential for IL-3-stimulated antiapoptotic signal transduction.

Animals↗