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Biomedical subjects

H Tanabe

Publications and source records attributed to H Tanabe.

At least 109 records · Page 6Linked to original sources
PubMed1998

"Disproportion theory" of the cervical spine and spinal cord in patients with juvenile cervical flexion myelopathy. A study comparing cervical magnetic resonance images with those of normal controls.

BACKGROUND: Cervical flexion myelopathy is quite a rare condition affecting mainly adolescent males who present with muscular atrophy of the upper extremities. Its etiology is still unknown, as is the cause of its marked male preponderance. Disproportion of the cervical spine and spinal cord is suspected to be one of the etiological causes, however, this has yet to be confirmed. METHODS: We performed a comparative study of the cervical magnetic resonance (MR) images of six male patients with juvenile cervical flexion myelopathy and of 34 young, normal controls. RESULTS: In normal controls, the cervical spines and spinal cords were significantly straighter in tall than in short males and in females than in males. In these patients, the cervical spine and spinal cord shapes were straighter, and the cervical spine length/height and cervical spinal cord length/height ratios were significantly higher than those of the height-matched male group. In the female group, the cervical spine and cervical spinal cord shapes were similar to the patient group; however, the cervical spine length/height and spinal cord length/height ratios as well as the heights were significantly smaller than those of the patients. CONCLUSIONS: The cervical spinal cords of the patients were considered to be stretched even with the neck in neutral position, reflecting disproportion of the cervical spine and spinal cord. The shorter length of the cervical spine and spinal cord in females was suspected to be one of the reasons for the marked male preponderance.

Adolescent↗
PubMed1998

Newly synthesized dihydropyridine derivatives as modulators of P-glycoprotein-mediated multidrug resistance.

Newly synthesized 1,4-dihydropyridine derivatives possessing alkyl chains at the 4-position screened whether they could overcome P-glycoprotein-mediated multidrug resistance in cultured cancer cells and also leukemia-bearing animals. Of these derivatives, some could overcome drug resistance to doxorubicin and vincristine in multidrug resistant human cancer cell lines. Combined administration of vincristine and some of the derivatives significantly increased the life span of P-glycoprotein overexpressing multidrug-resistant P388 leukemia-bearing mice. The calcium antagonistic activities, an undesirable effects, were weaker than that of verapamil. These results suggested that the introduction of alkyl groups at the 4-position were effective for both overcoming multidrug resistance and reducing the calcium antagonistic activity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Death-signalling cascade in mouse cerebellar granule neurons.

Molecular mechanisms of neuronal cell death are still largely unknown. In the present study, the signal transduction pathway of cell death in cerebellar granule neurons was examined by employing various death-preventative agents. When death was induced by the depletion of serum and a depolarizing level of potassium, transient increase in active c-Jun, mitochondrial membrane potential (deltapsi) loss, activation of caspase-3 (-like) proteases, and nuclear condensation and fragmentation were observed. The protein synthesis inhibitor cycloheximide blocked all these phenomena, whereas RNA synthesis inhibitor actinomycin-D, survival factor such as insulin-like growth factor-1, brain-derived neurotrophic factor, high K+ (25 mM) and overproduced antiapoptotic protein Bcl-2, prevented deltapsi, loss, caspase activation, and nuclear change, but not an increase in active c-Jun. The caspase inhibitor z-Asp-CH2-DCB (carbobenzoxy-L-aspartyl-alpha-[(2,6-dichlorobenzoyl) oxy]methane) only inhibited activation of caspases and nuclear change. These results suggest that the death signal in cerebellar granule neurons is sequentially transduced in the order of c-Jun activation, de novo RNA synthesis, mitochondrial deltapsi loss, activation of caspase-3 (-like) proteases and nuclear change.

Animals↗
PubMed1998

Amelioration of hippocampal neuronal damage after global ischemia by neuronal overexpression of BCL-2 in transgenic mice.

BACKGROUND AND PURPOSE: Reports suggesting the involvement of apoptosis in ischemic neuronal damage have been accumulating, and protection against apoptotic death by BCL-2 has been shown in many types of cells. Overexpression of BCL-2 has been shown to reduce infarct size after focal ischemia. The purpose of the present study was to assess whether BCL-2 exerted its effect on selective neuronal vulnerability after transient global ischemia. METHODS: Transgenic mice overexpressing BCL-2 in neurons and their littermates were subjected to transient forebrain ischemia for 12 minutes, and the hippocampus was examined 7 days later with conventional histology, immunohistochemistry, and in situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling of fragmented DNA. RESULTS: Although both types of mice showed a similar degree of ischemic insult, transgenic mice showed a lesser degree of neuronal death together with DNA fragmentation in the hippocampus than their littermates. CONCLUSIONS: Overexpression of BCL-2 in neurons mitigates selective neuronal vulnerability in the hippocampus of transgenic mice after transient global ischemia.

Animals↗
PubMed1998

Identification of the promoter region and the transcriptional regulatory sequence of the evgAS operon of Escherichia coli.

The evgAS operon of Escherichia coli encodes the EvgA response regulator and the EvgS sensory kinase, which are members of one of the two-component signal transduction systems of Escherichia coli. In this study, we identified the evg promoter and the EvgA-responsive element. Primer extension analysis found two evg transcriptional initiation sites, designated P1 (+1) and P2 (-10), and placed them 114 bp and 124 bp upstream of evgA, respectively. A gel retardation assay demonstrated that EvgA specifically bound to an inverted repeat located between -102 and -128 counting from P1. We also did a beta-galactosidase induction experiment using a promoter-probing vector and found that the EvgA-binding sequence was important to stimulate the evg promoter. These results suggest that the expression of evgAS is positively regulated by its own product, EvgA.

Bacterial Proteins↗
PubMed1998

Binding of the protein from Thermus aquaticus ISLtaq1 to its inverted repeat in vitro.

We have isolated from Thermus aquaticus an insertion-sequence-like genetic element (ISLtaq1) that induces thermotolerance and has a high sequence similarity to IS150 belonging to the IS3 family. An open reading frame on ISLtaq1, termed ORF1, encodes the ORF1 protein, which carries a DNA-binding motif. In this study, we found an imperfect inverted repeat in ISLtaq1. We next overproduced and purified a His-tagged ORF1 protein. Gel retardation analysis demonstrated that this protein specifically bound to an DNA fragment containing the inverted repeat in ISLtaq1. These results suggest that ISLtaq1 and the ORF1 protein are an insertion sequence and part of the transposase encoded by ISLtaq1, respectively.

Base Sequence↗
PubMed1998

Molecular interaction between proteins involved in EvgAS signal transduction of Escherichia coli.

EvgA and EvgS constitute one two-component signal transduction system in Escherichia coli. Although probable signaling domains of these proteins have been estimated, the molecular mechanism of their interaction remains to be elucidated. Here, we investigated protein to protein interactions between EvgA and EvgS and also between the EvgAS system and other related signaling pathways by means of surface plasmon resonance. EvgA and EvgS interacted directly and inhibition of phosphorylation of their functional domains abolished formation of the EvgAS complex. No interaction was observed either between EvgA and Bordetella BvgS or BvgA and EvgS. OmpR, a response regulator for the osmoregulative gene expression of E. coli, had similar but not identical behavior towards EvgS to that of EvgA. These results indicate that interaction between the signaling proteins is closely related to phosphorylation of the functional domain of the proteins.

Bacterial Outer Membrane Proteins↗
PubMed1998

[Japanese version of the Short-Memory Questionnaire: memory evaluation in Alzheimer's disease].

BACKGROUND AND PURPOSE: Memory deficit is a common sign of Alzheimer's disease (AD), which appeared generally in the early stage of the disease. Therefore, evaluation of memory is important for management of patients and for clinical research of AD. The Short-Memory Questionnaire (SMQ), an easily administered, informant-based scale, which was developed by Koss et al. (1993), is a standardized, validated, and reliable tool to assess everyday memory problems. In the present study, we prepared a Japanese version of the SMQ and examined its reliability and validity in assessing AD patients. SUBJECTS AND METHODS: The subjects consisted of 42 patients with NINCDS-ADRDA probable AD whose diagnosis was made on the basis of the results of comprehensive examinations including cranial CT/MRI and SPECT and age- and education-matched 53 healthy controls. Patients had no history of stroke, head injury, or any other prior neurological events. Patients and controls were between the ages of 51 and 90 years, and they had from 6 to 16 years education. The Japanese version of the SMQ was given to a family member by either neuropsychiatrist, public nurse or case worker. To evaluate test-retest reliability of the test, interview was repeated in 16 randomly selected patients by two different examiners (neuropsychiatrist and another) in two weeks interval. The Mini-Mental State Examination (MMSE) was used to assess the severity of cognitive impairment. RESULT: The test-retest reliability was acceptably high with intraclass correlation coefficients. There was a high correlation between scores of SMQ and MMSE. The SMQ had excellent specificity and sensitivity in discriminating patients from controls. Caregiver appraisals of memory deficits significantly correlated with generalized cognitive dysfunction. CONCLUSIONS: Similarly to the original version, the present Japanese version of the SMQ is a reliable and valid tool in assessing memory function in AD, which can be effectively used in clinical settings and epidemiologic studies to screen out persons with memory problems.

Aged↗
PubMed1998

[Releasing phenomenon of learned movements].

Involuntary movements that resembled the shooting of a basketball and piano playing were observed after brain damage in a 13-year-old female and a 74-year-old female, respectively. The movements were characterized as involuntarily triggered movements that occurred in the presence and absence of exteroceptive stimuli, movements had been practiced repeatedly just before the occurrence of the brain damage, and that could be stopped on command. According to the MRI findings, the lesions extended into the pre-supplementary motor area (pre-SMA). The characteristics of the patients movements were different from previously reported involuntary movements such as compulsive manipulation of tools, utilization behavior, and imitation behavior. Hikosaka et al (1996) reported the role of the pre-SMA in learning new sequential procedures. We speculate that damage to the pre-SMA may be associated with the etiology of these movements.

Adolescent↗
PubMed1997

Extensive genetic heterogeneity in the neuroblastoma cell line NB(TU)1.

A neuroblastoma cell line displaying genetically unique features was established from a stage III case of a 20-month-old girl. Southern blotting by the probe pTNB6, which contains exon 1 of the N-myc gene, showed that the primary tumor had in total 4 aberrant bands beside the normal amplified band. The established cell line NB(TU)1 had an aberrant N-myc band (9.0 kb) in addition to the normal band (2.9 kb). Cytogenetic analysis revealed that NB(TU)1 has a composite karyotype composed of at least 7 related karyotypes, which are pseudo-diploid and contain complex chromosomal abnormalities, including translocations, deletions and homogeneously staining regions (HSRs). Such extensive abnormalities were considered to be prominent among known neuroblastoma cell lines, and it was suggested that NB(TU)1 had acquired a certain type of genetic instability. Analysis of N-myc bands in 11 clones of NB(TU)1 showed that the intensity ratio of the normal-sized band (2.9 kb) and the aberrant one (9.0 kb) markedly varied among clones. Moreover, 3 clones showed an additional band with the size of 3.7 kb, which was detectable neither in the parent NB(TU)1 nor in the primary tumor. Thus, NB(TU)1 was shown to be composed of heterogeneous cell components. To further detect such ongoing chromosomal instability, we examined micronuclei formation. NB(TU)1 yielded a larger number of micronuclei than 5 other neuroblastoma cell lines. We conclude that NB(TU)1 has acquired genetic instability detectable by both Southern blotting and cytogenetic analysis.

Abdominal Neoplasms↗
PubMed1997

Relationship between the recurrence of hepatocellular carcinoma (HCC) and serum alanine aminotransferase levels in hepatectomized patients with hepatitis C virus-associated cirrhosis and HCC.

BACKGROUND: The relationship between the recurrence of hepatocellular carcinoma (HCC) and the serum alanine aminotransferase (ALT) level was studied in hepatectomized patients with hepatitis C virus (HCV)-associated cirrhosis and HCC. METHODS: Twenty-six hepatectomized patients with HCV-associated cirrhosis and HCC whose resected specimens showed neither portal vein nor hepatic vein invasion by HCC histologically were divided into 2 groups: 15 patients who had no recurrence 3 years after surgery (Group A) and 11 patients whose disease recurred 1-3 years after surgery (Group B). The patients' serum ALT levels during this period were examined. RESULTS: In Group A, serum ALT generally showed sustained low levels < 80 international units (INU) in 12 patients (80%). In contrast, ALT levels in Group B showed several peaks or plateaus > 80 INU in all patients except 2. The recurrence rate of HCC in the hepatectomized patients with sustained low levels of ALT was 14.3% (2 of 14 patients) at 3 years, and was significantly lower (P < 0.01) than that in those patients whose ALT levels showed several peaks or plateaus > 80 INU (9 of 12 patients; 75.0%). The average level of mode of ALT in Group A (48.8 +/- 26.0 INU) was significantly smaller than that in Group B (101.1 +/- 47.3 INU) (P < 0.005). CONCLUSIONS: The importance of hepatocytic necrosis in the recurrence of HCC in hepatectomized patients with cirrhosis and HCC of HCV origin was demonstrated and the significance of subsiding hepatic necroinflammatory process in the prevention of HCC recurrence suggested.

Aged↗
PubMed1997

Morphologic study of the mandibular fossa and the eminence of the temporomandibular joint in relation to the facial structures.

To clarify the relationship between the temporal component of the temporomandibular joint and facial bone structure, we measured anthropologic craniometric points and the structure of the mandibular fossa, including the eminence in 33 Japanese male dry skulls, with a three-dimensional apparatus. The length from the articular tubercle to the medial glenoid tubercle is correlated with skeletal variables such as the length of the fossae, the width of the masseter origin, and the mandibular length. Therefore it appears that the frontal dimension is related to the facial development, which is attributable to bite force. Goniometrically, the angle between the line deepest point of the fossa--the midpoint of the eminence and the Frankfort horizontal plane (middle angle)--was negatively correlated only with the ANB angle, suggesting that a steeper middle angle of the eminence is related to a retrusive maxilla or protrusive mandible.

Adolescent↗
PubMed1997

Susceptibility of cerebellar granule neurons derived from Bcl-2-deficient and transgenic mice to cell death.

Overproduced Bcl-2 oncoprotein has been shown to suppress cell death induced by a variety of stimuli in many cell types, including neuronal cells. Because bcl-2 is expressed in the nervous system where massive cell death is observed during development, endogenous Bcl-2 is likely to be involved in regulating neuronal cell death. Here we examined the possible role of endogenous Bcl-2 in the regulation of neuronal cell survival in the central nervous system using primary cultured cerebellar granule neurons from bcl-2-deficient, wild-type and NSE-bcl-2-transgenic mice. Cerebellar granule neurons from bcl-2-deficient mice were more susceptible than those from normal littermates to death induced by reducing the K+ concentration of the medium from high (25 mM) to low (5 mM), and neurons from bcl-2-transgenic mice were least susceptible. Similar results were obtained when cell death was induced by serum withdrawal under high K+ conditions or by the presence of etoposide, A23187 or nimodipine. Consistently, bcl-2 deficiency reduced the number of cerebellar granule neurons per mouse. These results indicate that Bcl-2 impedes neuronal cell death induced by various stimuli in a dose-dependent manner, and that endogenous levels of Bcl-2 are able to regulate neuronal cell survival in the central nervous system.

Animals↗
PubMed1997

Loss of large myelinated nerve fibres of the recurrent laryngeal nerve in patients with multiple system atrophy and vocal cord palsy.

OBJECTIVES: Vocal cord palsy seen in some patients with multiple system atrophy may result from neuronopathy of the recurrent laryngeal nerve. METHODS: Six controls and six patients with multiple system atrophy, four with and two without vocal cord palsy were studied. The number of myelinated nerve fibres were counted and fibre diameter histograms were established for the motor and sensory divisions of the laryngeal branch of the recurrent laryngeal nerve. RESULTS: Although both groups of patients with multiple system atrophy showed selective loss of the myelinated fibres in the motor branch, the change was greater in those with vocal cord palsy than in those without. The small myelinated nerve fibres (diameter < 7 microm) were decreased in number in both multiple system atrophy groups, whereas the large myelinated nerve fibres (diameter < 8 microm) were decreased only in those with vocal cord palsy, and preserved in those without the symptom. CONCLUSION: In multiple system atrophy, the small myelinated fibres innervating the vocal cord are affected first, without obvious clinical signs. The patient develops vocal cord palsy only after the loss of the large myelinated fibres, which mostly comprise the alpha motor axons that innervate the intrinsic laryngeal muscles.

Atrophy↗
PubMed1997

Adult-onset type II citrullinemia: clinical pictures before and after liver transplantation.

In a 25-year-old man with adult-onset type II citrullinemia, liver transplantation resulted in elimination of hyperammonemia and amino acid abnormalities associated with the disease. Postoperatively, a high intensity area in the right cingulate gyrus on a T2-weighted brain magnetic resonance imaging (MRI) also disappeared, suggesting that it reflected an early reversible lesion due to the hyperammonemia. Moreover, the serum level of pancreatic secretory trypsin inhibitor (PSTI), which had been elevated, was normalized. Since the levels of PSTI mRNA and PSTI have been reported to be increased in the livers of type II citrullinemia patients, measurement of serum PSTI levels could aid in the diagnosis of this disease.

Adult↗
PubMed1997

Comparison of iodine-123-iomazenil SPECT and technetium-99m-HMPAO-SPECT in Alzheimer's disease.

UNLABELLED: This study was designed to elucidate a central type of benzodiazepine (Bz) receptor distribution in patients with Alzheimer's disease using SPECT with [123I]iomazenil (IMZ). METHODS: Eight patients with probable Alzheimer's disease were studied. Benzodiazepine receptor imaging was performed 15 min (early) and 180 min (delayed) after intravenous administration of 167 MBq IMZ, sequentially, using hexamethylpropylene amine oxime (HMPAO) SPECT to evaluate regional cerebral perfusion. RESULTS: Early IMZ-SPECT depicted areas of reduced uptake in sites of decreased cerebral blood flow (CBF), but each area of decreased uptake was extended wider than the area of hypoperfusion. Delayed IMZ-SPECT images demonstrated a similar pattern of decreased area of CBF; the affected region in Bz receptor bindings, however, was clearer and broader compared with that in either HMPAO-SPECT or early IMZ-SPECT. In comparison with the uptakes for the normal cerebral hemisphere (ratio to the contralateral cerebellum) in patients with unilateral cerebral infarction as a control group (n = 4), the patients with Alzheimer's disease showed distinctive bilateral frontal or parietal defects (p < 0.05). CONCLUSION: Brain SPECT using IMZ may be more sensitive than CBF images in patients with Alzheimer's disease.

Alzheimer Disease↗