Biomedical subjects

K Terada

Publications and source records attributed to K Terada.

At least 127 records · Page 7Linked to original sources

PubMed1998

[Multivariate analysis of the associations between laboratory data and clinical features among patients with infectious mononucleosis syndrome].

Infectious mononucleosis (IM) syndrome is typically caused by EBV, but also by drugs and other organisms such as CMV and HBV. It demonstrates a wide range of clinical and laboratory characteristics, presumably depending on the age of onset. However, associations of laboratory abnormalities with the clinical features have not been well documented. We evaluated here, the associations among patients with IM syndrome using of multiple regression (MR) and multiple logistic regression (MLR) analyses. We examined 90 (40 males, 50 females) patients, who were admitted to our hospital with IM syndrome. The diagnostic criteria were fever and presence of atypical lymphocytes (> 5% of the WBC or the count including monocytes > 5000/microliter), and at least 3 of 7 clinical features: tonsillitis, lymphadenopathy, skin rash, hepato-, spleno-megaly, hepatic dysfunction. The diagnosis of EBV was serologically confirmed in 41 cases. MR revealed that the higher age group tended to have lower platelet counts, and that lower platelet counts were associated with higher ALT levels. In addition, MLR revealed that patients with skin rash tended not to have splenomegaly. The frequency of splenomegaly was not related to age, contrary to the findings of previous reports. These findings are useful to differentiate IM syndrome based on laboratory data.

Adolescent↗

PubMed1998

Detection of varicella-zoster virus DNA in peripheral mononuclear cells from patients with Ramsay Hunt syndrome or zoster sine herpete.

On the basis of alterations in varicella-zoster virus (VZV) antibody titers, it appears that Bell's palsy in some patients could be associated with VZV reactivation, that is, zoster sine herpete. To obtain stronger evidence of this association, polymerase chain reaction (PCR) was used to detect VZV DNA in auricular lesions or peripheral blood mononuclear cells (PBMCs) from Bell's palsy or Ramsay Hunt syndrome patients. VZV DNA was detected in the auricular lesions of Ramsay Hunt syndrome, in PBMCs from 2 Ramsay Hunt syndrome patients, and in 4 of 17 samples from 16 Bell's palsy patients. Three of these four positive patients were thought to have zoster sine herpete because of hearing difficulty, vertigo, and pain. VZV IgM antibodies were positive in 1 of the 2 patients with Ramsay Hunt syndrome, and in 2 of the 17 samples from the Bell's palsy patients. VZV IgG antibody titers during the acute phase were significantly higher in the patients positive for the PCR or VZV IgM antibody than in those negative for them. These findings provide evidence that Bell's palsy in some patients could be associated with VZV reactivation.

Adolescent↗

PubMed1997

Positive evidence that anti-Toxoplasma gondii IgA antibody exists in the intestinal tract of infected cats and exerts protective activity against the infection.

The presence of anti-Toxoplasma gondii IgA antibody in the feces and intestinal tract of cats infected with this parasite was demonstrated using an immunoblotting assay. Cats (n = 5) were inoculated orally with T. gondii cysts and supernatants of feces and washings of the intestinal tract were assayed for secretory IgA specific for the parasite. The secretory IgA detected recognized tachyzoite antigens of m.w. 24, 34, 38 and 43 kDa and one sporozoite antigen of m.w. 24 kDa. No reactivity was shown against bradyzoites or enteroepithelial stage parasites. Tachyzoites preincubated with washings of the intestinal tract of infected cats showed decreased activity in penetration of feline fibroblast cells, as compared to tachyzoites preincubated with similar washings derived from non-infected cats. The addition of either anti-cat IgA or anti-cat IgG to the washings had no effect on the inhibitory activity which reduced the parasite's cell-penetration activity. However, the addition of both anti-cat IgA and anti-cat IgG to the washings diminished the inhibitory activity. These results suggest that anti-T. gondii antibodies of both classes, secretory IgA and IgG, exist in the intestinal tract of infected cats and these may be capable of preventing infection.

Animals↗

PubMed1997

The human DnaJ homologue dj2 facilitates mitochondrial protein import and luciferase refolding.

DnaJ homologues function in cooperation with hsp70 family members in various cellular processes including intracellular protein trafficking and folding. Three human DnaJ homologues present in the cytosol have been identified: dj1 (hsp40/hdj-1), dj2 (HSDJ/hdj-2), and neuronal tissue-specific hsj1. dj1 is thought to be engaged in folding of nascent polypeptides, whereas functions of the other DnaJ homologues remain to be elucidated. To investigate roles of dj2 and dj1, we developed a system of chaperone depletion from and readdition to rabbit reticulocyte lysates. Using this system, we found that heat shock cognate 70 protein (hsc70) and dj2, but not dj1, are involved in mitochondrial import of preornithine transcarbamylase. Bacterial DnaJ could replace mammalian dj2 in mitochondrial protein import. We also tested the effects of these DnaJ homologues on folding of guanidine-denatured firefly luciferase. Unexpectedly, dj2, but not dj1, together with hsc70 refolded the protein efficiently. We propose that dj2 is the functional partner DnaJ homologue of hsc70 in the mammalian cytosol. Bacterial DnaJ protein could replace mammalian dj2 in the refolding of luciferase. Thus, the cytosolic chaperone system for mitochondrial protein import and for protein folding is highly conserved, involving DnaK and DnaJ in bacteria, Ssa1-4p and Ydj1p in yeast, and hsc70 and dj2 in mammals.

Biological Transport↗

PubMed1997

Two forms of Wilson disease protein produced by alternative splicing are localized in distinct cellular compartments.

Copper is an essential trace element in prokaryotes and eukaryotes and is strictly regulated by biological mechanisms. Menkes and Wilson diseases are human disorders that arise from disruption of the normal process of copper export from the cytosol to the extracellular environment. Recently a gene for Wilson disease (WD)(also named the ATP7B gene) was cloned. This gene encodes a copper transporter of the P-type ATPase. We prepared monoclonal and polyclonal anti-(WD protein) antibodies and characterized the full-length WD protein as well as a shorter form that is produced by alternative splicing in the human brain. We found that the WD protein is localized mainly in the Golgi apparatus, whereas the shorter form is present in the cytosol. These results suggest that the alternative WD proteins act as key regulators of copper metabolism, perhaps by performing distinct roles in the intracellular transport and export of copper.

Adenosine Triphosphatases↗

PubMed1997

The effect of silver administration on the biosynthesis and the molecular properties of rat ceruloplasmin.

To examine the cause of the altered ceruloplasmin (Cp) metabolism by silver administration, we analysed the properties of serum Cp by gel filtration chromatography, affinity chromatography and polyacrylamide gel electrophoresis. Metal contents in the Cp fraction from the silver-treated group were estimated as approximately 0.8 atom of silver and 4.2 atoms of copper per molecule, and as 5.9 atoms of copper for the control group. These findings confirm that holo-Cp from rat serum administered with silver nitrate exists as a silver-bound inactive form, suggesting that silver displaces one of Cp's copper atoms associating with oxidase activity. Matured holo-Cp also appeared in the Golgi in both groups, however, the amounts of enzymatically active holo-Cp showed a decrease after silver administration, while the apo-Cp level was hardly changed. These findings suggest that silver-bound holo-Cp is accomplished at Golgi.

Animals↗

PubMed1997

Visualization of mitochondrial protein import in cultured mammalian cells with green fluorescent protein and effects of overexpression of the human import receptor Tom20.

The presequence of the ornithine transcarbamylase precursor (pOTC) was fused to green fluorescent protein (GFP), yielding pOTC-GFP and pOTCN-GFP containing the presequence plus 4 and 58 residues of mature ornithine transcarbamylase, respectively. When GFP cDNA was transfected into COS-7 cells, the cytosol and nucleus were fluorescent. On the other hand, pOTC-GFP cDNA gave strong fluorescence of a unique mitochondrial pattern. After fractionation of cells expressing pOTC-GFP with digitonin, fluorescence was recovered mostly in the particulate fraction. Immunoblot analysis showed that processed GFP was present in the particulate fraction, whereas pOTC-GFP was recovered in both the soluble and particulate fractions. pOTC-GFP and pOTCN-GFP synthesized in vitro were imported efficiently into the isolated mitochondria. Single and triple amino acid mutations in the presequence resulted in impaired mitochondrial import and in a loss of mitochondrial fluorescence. Perinuclear aggregation of fluorescent mitochondria was observed when the human mitochondrial import receptor Tom20 (hTom20) was coexpressed with pOTC-GFP. Overexpression of hTom20 (not DeltahTom20, which lacks the anchor sequence) resulted in stimulated mitochondrial import of pOTC-GFP in COS-7 cells. When pOTC-GFP cDNA was microinjected into nuclei of human fibroblast cells, mitochondrial fluorescence was detected as early as 2-3 h after injection. These results show that GFP fusion protein can be used to visualize mitochondrial structures and to monitor mitochondrial protein import in a single cell in real time.

Animals↗

PubMed1997

Participation of the import receptor Tom20 in protein import into mammalian mitochondria: analyses in vitro and in cultured cells.

Requirement of the mitochondrial import receptor Tom20 in protein import into mammalian mitochondria was studied in vitro and in cultured cells. Import of human and rat pre-ornithine transcarbamylase (pOTC), pig pre-aspartate aminotransferase (pAAT) and rat serine: pyruvate aminotransferase (pSPT) was inhibited by delta hTom20 that lacks the NH2-terminal transmembrane domain of human Tom20 (hTom20). Import of these preproteins was also inhibited by anti-Tom20. The inhibitions by delta hTom20 and anti-hTom20 were the strongest for human pOTC, followed by rat pOTC, pAAT and pSPT. Coexpression of human pOTC and hTom20 in COS-7 cells followed by immunoblot analysis showed that overexpression of hTom20, but not delta hTom20, decreases production of mature OTC. In pulse-chase experiments, pOTC was synthesized and rapidly processed to the mature form. Coexpression of hTom20, but not delta hTom20, resulted in a decrease of pOTC processing, probably due to an imbalance of the normal stoichiometry of the receptor complex. These results show that both in vitro and in intact cells, Tom20 is involved in mitochondrial protein import in higher animals and that the requirement for Tom20 is different for different preproteins.

Animals↗

PubMed1997

Ras-dependent activation of c-Jun N-terminal kinase/stress-activated protein kinase in response to interleukin-3 stimulation in hematopoietic BaF3 cells.

Activation of the c-Jun N-terminal kinase (JNK)/stress-activated protein kinase pathway in response to stimulation of the interleukin (IL)-3 or granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor was examined in mouse hematopoietic BaF3-derived cell lines (BaF3-N6 and -V2 cells). Significant increase in the activity of JNK1 was observed within 30 min following IL-3 or GM-CSF stimulation at physiological concentrations. Dominant-negative Ras(S17N), which is conditionally expressed in the presence of isopropyl-1-thio-beta-D-galactoside in BaF3-N6 cells, prevented the IL-3 stimulation of JNK1, whereas anisomycin-induced JNK1 activation was unaffected. Furthermore, a deletion mutant of the common beta subunit for IL-3 and GM-CSF receptors that consists of only the membrane-proximal region, including box 1 and box 2 motifs, was incapable of facilitating JNK1 activity as well as Ras activation. These results provide evidence that Ras is required for IL-3-stimulated JNK1 activation. We also examined if constitutively active Ras(G12V) alone could stimulate JNK1 activity by using the inducible expression system. Isopropyl-1-thio-beta-D-galactoside induction of Ras(G12V) in the BaF3-V2 cell line caused no significant increase in JNK1 activity, which could be activated by IL-3 or anisomycin. On the contrary, the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway was fully activated following Ras(G12V) induction. Together with these results, it seems likely that the Ras protein is indispensable for the IL-3 stimulation of JNK1 although Ras activation by itself is insufficient for JNK1 activation.

Animals↗

PubMed1997

Familial cortical myoclonic tremor as a unique form of cortical reflex myoclonus.

Previously it was reported that some patients with tremor had the same electrophysiological findings as those seen in patients with cortical reflex myoclonus, and consequently the tremor was named "cortical tremor." In the present study, we examined six patients from three families with cortical tremor of relatively late onset. The inheritance pattern of cortical tremor was compatible with autosomal dominant trait. Those patients had relatively rhythmic involuntary movements (tremor) in the distal upper and lower limbs, especially during posture and/or fine movements. There was no cerebellar ataxia or dementia, and fits of loss of consciousness occurred only infrequently. Electrophysiologically, they had generalized spikes on electroencephalogram (EEG), giant cortical components of somatosensory evoked potential, an enhanced long-loop reflex (C-reflex), and cortical spikes preceding the rhythmic jerk demonstrable by the jerk-locked back averaging method, thus fulfilling the criteria of cortical reflex myoclonus. Furthermore, they had slow negative EEG shift starting 1-2 s prior to voluntary movements, suggesting that, as opposed to the conventional form of progressive myoclonus epilepsy (PME), the cerebellar efferent input to the motor cortices was normal. These clinical and electrophysiological pictures are distinct from those of familial essential tremor, familial essential myoclonus, or the conventional form of PME, and the term "familial cortical myoclonic tremor" will represent the clinical and electrophysiological features of this unique entity most appropriately.

Adult↗

PubMed1997

Simultaneous recording of epileptiform discharges by MEG and subdural electrodes in temporal lobe epilepsy.

Spontaneous epileptiform discharges were recorded by whole head magnetoencephalography (MEG) and subdural electrodes simultaneously from two patients with medically intractable temporal lobe epilepsy. In one patient whose epileptiform discharges emerged from the lateral temporal lobe, simultaneously recorded MEG could estimate equivalent current dipole reliably near the tumor. The amplitude of the dipole was in proportion not only to the amplitude of epileptiform discharge but also to the number of subdural electrodes involved. In the other patient, MEG detected only a small proportion of epileptiform discharges, even when they were recorded by subdural electrodes from the mesial temporal lobe. It is concluded that the amplitude and the depth of epileptiform discharges would largely affect the sensitivity of dipole localization by MEG.

Adult↗

PubMed1997

Presurgical identification of epileptic foci with iodine-123 iomazenil SPET: comparison with brain perfusion SPET and FDG PET.

Iodine-123 iomazenil (IMZ) has excellent characteristics for the quantification of central benzodiazepine receptor (BZR) binding with single-photon emission tomography (SPET). In order to evaluate the clinical value of IMZ SPET for presurgical identification of epileptic foci in patients with medically intractable seizures, we measured the binding potential (BP) of BZR using two IMZ SPET scans and compared the results with brain perfusion SPET and fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET). A total of ten patients with intractable partial epilepsy were examined by electroencephalography, magnetic resonance imaging, FDG PET, brain perfusion SPET and IMZ SPET. After neuroimaging examinations, five patients underwent selective surgery, and all of them have since been free of seizures. Two SPET scans were performed at 15 min (early) and 3 h (late) after intravenous injection of 123I-IMZ (167 MBq). Parametric images of the ligand transport (K1) and binding potential (BP) were calculated by the table look-up method, which is based on a three-compartment two-parameter model, using the standard arterial input function obtained by averaging of six normal volunteers' input functions. BP images delineated the epileptic foci more precisely than either FDG PET or ictal perfusion SPET. FDG PET showed widespread reduction, including the area surrounding the focus, and ictal increase in the cerebral blood flow was seen in possibly activated areas spread from the focus. In four epilepsy cases which originated from the mesial temporal lobe without lateral temporal abnormality, there was no significant decrease in the BP images in the lateral temporal structures, which showed decreased uptake of FDG. It is concluded that parametric images of BP with IMZ are valuable for precise presurgical localization of epileptic foci.

Adult↗

PubMed1997

Isolation of coccidian enteroepithelial stages of Toxoplasma gondii from the intestinal mucosa of cats by Percoll density-gradient centrifugation.

A method for isolation of enteroepithelial stages of Toxoplasma gondii from the intestinal mucosa of experimentally infected cats was developed using Percoll density-gradient centrifugation. Gamonts and merozoites were obtained essentially free of host-cell debris. A recovery rate of nearly 30% of the parasites in the original preparations was obtained by this method. Merozoites were separated from gamonts by filtration through a 3-micron polycarbonate filter.

Animals↗

PubMed1997

Afferent mechanism of cortical myoclonus studied by proprioception-related SEPs.

Proprioception-related somatosensory evoked potentials (SEPs) to passive flexion movement of the middle finger at proximal interphalangeal joint were recorded in 7 patients with myoclonus of cortical origin who demonstrated enlarged electrical SEPs (giant SEPs). In 3 out of the 7 patients, the proprioception-related SEPs were also enlarged. The remaining 4 patients showed giant electrical SEPs without enhancement of proprioception-related SEPs. Long loop electromyographic response was recorded during the resting condition in all of the 3 patients with enlarged proprioception-related SEPs. We have previously reported that proprioception-related SEPs are mainly generated by muscle afferent inputs, though electrical SEPs are thought to reflect mostly cutaneous inputs with some contribution from muscle afferents. Therefore, it is concluded that hyperexcitability of the sensorimotor cortex in cortical myoclonus is modality-specific. Cortical excitability is exaggerated to both cutaneous and deep receptor inputs in some patients, but only to cutaneous input in others.

Adult↗

PubMed1997

Modality-specific organization for cutaneous and proprioceptive sense in human primary sensory cortex studied by chronic epicortical recording.

Modality specificity of human primary somatosensory cortex was studied by recording somatosensory evoked potentials (SEPs) from subdural electrodes in a patient with intractable focal motor seizure. A newly developed device was used for selectively activating proprioception. The spatial and temporal distributions of proprioception-related SEPs elicited by brisk passive flexion movement at the proximal interphalangeal (PIP) joint of the middle finger (4 degrees in 25 ms) were quite different from those to cutaneous sense evoked by electric stimulation of the digital nerve at the same site. It was for the first time demonstrated that proprioception-related SEPs following passive finger movement do not originate in area 3b, which was clearly activated by cutaneous stimulation, and that other sites at the sensorimotor cortex such as areas 2, 3a and 4 possibly contribute to the cortical processing of proprioception.

Adult↗

PubMed1997

Dissociation between contingent negative variation (CNV) and Bereitschaftspotential (BP) in patients with parkinsonism.

In order to clarify the generator mechanism of the late component of contingent negative variation (CNV), we compared the late CNV with Bereitschaftspotential (BP) in patients with parkinsonism (Parkinson's disease and progressive supranuclear palsy). In patients with mild symptoms (Hoehn Yahr grade I and II) both the late CNV and BP were clearly seen. In patients with severe symptoms (Hoehn Yahr grade III, IV and V) the BP was normally seen, but the late CNV was significantly smaller or absent (P < 0.001 at Cz) and it was also significantly smaller than that obtained from age-matched normals. In one patient (H-Y grade II) who had normal BP, the late CNV was diminished selectively at the midline area. Since it was reported that the late CNV arises from at least the supplementary motor area (SMA), selective diminution of the late CNV at the midline could be explained by the decreased activity of the SMA in parkinsonism. It was also previously reported that the BP was absent but the late CNV was normally present in a patient with cerebellar efferent lesion (Ikeda et al., 1994). Taken together with the experimental results indicating that movement-related neurons in the putamen behave contingent on external stimuli, it is suggested that subcortical generating mechanism is different for the late CNV and BP although both commonly share at least some cortical generators, and that the basal ganglia are most likely responsible for the generation of the late CNV and the cerebellar efferent system for the generation of the BP.

Adult↗

PubMed1997

Cortical mechanism underlying externally cued gait initiation studied by contingent negative variation.

In order to clarify the cortical mechanism underlying gait initiation, we examined the scalp distribution of the contingent negative variation (CNV) preceding externally cued gait initiation in a simple reaction-time paradigm in 10 healthy right-handed men, and compared the results with the CNV preceding simple foot dorsiflexion. A pair of auditory stimuli was given with an interstimulus (S1-S2) interval of 2 s and gait consisting of at least 3 steps was initiated with the right footstep as fast as possible in response to S2. Brisk dorsiflexion of the right foot was employed as a control task. It was found that the late CNV in the gait initiation task started about 1 s before S2, and was largest at Cz (-9.3 +/- 3.1 microV) without clear asymmetry over the scalp. However, it was ill defined in the parietal area. In the foot dorsiflexion task, the late CNV was maximal at Cz (-7.1 +/- 2.9 microV), and clearly seen also over the parietal area. The late CNV at Cz was significantly (P < 0.01) larger in the gait initiation than in the simple foot dorsiflexion. The amplitude of the late CNV preceding the foot dorsiflexion task was not significantly different between the sitting and the standing posture. In view of the results of previous invasive studies in both humans and animals which showed some frontal areas, including the supplementary motor area (SMA) and the primary motor cortex, as the generators of the late CNV, it is suggested that the cerebral cortex is active in initiation of externally triggered gait in a different way from the simple foot movement, and that bilateral SMAs may play a more important role in gait initiation than in simple foot movement.

Adolescent↗

PubMed1997

Continuous transoesophageal echocardiography monitoring during weaning from cardiopulmonary bypass in children.

The purpose of this study was to evaluate the effectiveness of transoesophageal echocardiography monitoring during weaning from cardiopulmonary bypass after intracardiac repair in children. The left ventricular ejection fraction, left ventricular end-diastolic volume and left ventricle wall motion were monitored continuously by transoesophageal echocardiography in controls weaned easily from cardiopulmonary bypass (group A, n = 25), and those weaned with difficulty from cardiopulmonary bypass after mechanically assisted circulation (group B, n = 16). In group A, left ventricular ejection fraction and left ventricle wall motion were within normal range, and did not change significantly during weaning after cardiopulmonary bypass when compared with pre-bypass data. In contrast, left ventricular ejection fraction, left ventricular end-diastolic volume and left ventricle wall motion in group B during the first trial of weaning from bypass were significantly worsened. Hence, assisted circulation was performed until the data obtained via transoesophageal echocardiography improved with regard to maintenance of fluid balance, catecholamine dosage and assisted pump flow. All cases in group B were weaned safely from cardiopulmonary bypass despite their critical condition. In conclusion, continuous transoesophageal echocardiography monitoring may be a useful tool in children with severe heart failure for safe weaning from cardiopulmonary bypass after intracardiac repair.

Adolescent↗