PubMed Health⌕ Search

Biomedical subjects

M Taoka

Publications and source records attributed to M Taoka.

15 recordsLinked to original sources
PubMed1996

Changes in the gene expression of a protein with the cdc10/SWI6 motif, V-1, during rat follicular development and corpus luteum formation.

We examined the gene expression of V-1, a novel soluble protein with the cdc10/SWI6 motif, in pseudopregnant rat ovaries. Northern blot analysis on days 1, 5, and 11 of pseudopregnancy revealed an approximately 2-fold increase in the V-1 messenger RNA (mRNA) expression level on day 5 to that on day 1, and no significant change was observed between those on day 5 and day 11. An injection of human CG on days 5 further increased th V-1 mRNA level to about 1.6-fold of that of the untreated control. Western blot analysis showed higher V-1 protein expression on days 5 and 11 of pseudopregnancy than that on day 1. In situ hybridization and immunohistochemistry with ovaries on day 3 of pseudopregnancy showed that luteal cells of corpora lutea and also cells of the coexisting follicles including oocytes express V-1 mRNA and the protein, with apparent rank order of the expression: oocytes > luteal cells > follicular cells >> atretic follicular cells including oocytes. These data indicate the dynamic change in the V-1 gene expression in the ovarian steroidogenic cells and oocytes and suggest potential roles of the V-1 protein in ovarian functions including corpus luteum formation and folliculogenesis.

Animals↗
PubMed1994

A nuclear factor containing the leucine-rich repeats expressed in murine cerebellar neurons.

A nuclear protein, termed leucine-rich acidic nuclear protein (LANP), has been isolated from among rat cerebellar proteins whose expression was transiently increased during an early stage of postnatal development. The amino acid sequence, deduced from its cDNA, showed that LANP contains 247 amino acids consisting of two distinct structural domains: the N-terminal domain characterized by "leucine-rich repeat," which is found in many eukaryotic proteins and which potentially functions in mediating protein-protein interactions, and the C-terminal domain characterized by a cluster of acidic amino acids with a putative nuclear localization signal. Immunohistochemical study using an antibody against LANP revealed that the protein is localized mainly in nuclei of Purkinje cells. In the rat cerebellum on postnatal day 7, LANP mRNA was expressed moderately in the external granule and Purkinje cells and weakly in the internal granule cells. The expression in these cells, especially in Purkinje cells, increased in the second postnatal week and thereafter decreased to an adult level. The structural characteristics, localization, and the stage- and cell type-specific expression suggest a potential role of LANP in a signal transduction pathway that directs differentiation of cerebellar neurons.

Aging↗
PubMed1994

Murine cerebellar neurons express a novel gene encoding a protein related to cell cycle control and cell fate determination proteins.

We cloned cDNAs of a novel protein (designated V-1) that has been identified from among the developmentally regulated proteins in the rat cerebellum. Protein sequencing analysis (Taoka, M., Yamakuni, T., Song, S.-Y., Yamakawa, Y., Seta, K., Okuyama, T., and Isobe, T. (1992) Eur. J. Biochem. 207, 615-620) and cDNA sequence analysis revealed that the V-1 protein consists of 117 amino acids and contains 2.5 contiguous repeats of the cdc10/SWI6 motif, which was originally found in the products of the cell cycle control genes of yeasts and the cell fate determination genes in Drosophila and Caenorhabditis elegans. In situ hybridization histochemistry revealed that the expression of the V-1 gene is transiently increased in postmigratory granule cells during postnatal rat cerebellar development and thereafter is markedly suppressed, whereas Purkinje cells constitutively express V-1 mRNA. In contrast, cerebellar granule cells of the staggerer mutant mouse continue to express the V-1 gene even when the granule cells of the normal mouse have ceased to express the V-1 gene, suggesting that the expression of the V-1 gene in granule cells is regulated through the interaction with Purkinje cells. On the basis of these results, we postulate that the V-1 protein has a potential role in the differentiation of granule cells.

Amino Acid Sequence↗
PubMed1992

A rat cerebellar protein containing the cdc10/SWI6 motif.

Systematic analysis of soluble proteins in developing rat cerebellum by an automated two-dimensional liquid-chromatography system detected a number of proteins which increased transiently during the initial stage of postnatal development. One of the proteins, V-1, was isolated using a liquid-chromatography system, and its amino acid sequence was determined by analysis of the purified protein. The sequence showed that the V-1 protein consists of 117 amino acids with an acetylated N-terminus, and has 2.5 internal sequence repeats of 33 amino acids. Computer retrieval of the sequence indicated that the repeated sequences have a structural characteristics of the cdc10/SWI6 motif, which is found in a series of proteins, including those involved in cell-cycle control and cell-fate determination in yeast, Drosophila melanogaster and Caenorhabditis elegans. The structure of V-1, coupled with its controlled expression in early postnatal development, implies a potential role for V-1 in cerebellar morphogenesis.

Amino Acid Sequence↗
PubMed1991

Automated two-dimensional liquid chromatographic system for mapping proteins in highly complex mixtures.

An automated two-dimensional liquid chromatographic system was developed for systematic protein separations which could serve for analytical mapping and preparative separations of proteins. The system applies the principles of the column-switching technique, and consists of two different columns connected in tandem through an electrical column switching valve, two pumping systems to operate each column independently and a system controller to perform sequential chromatography on the two columns. A protein mixture is applied to the first-dimensional anion-exchange column and is separated by stepwise elution with an increasing sodium chloride concentration. The eluent is introduced directly to the second-dimensional reversed-phase column, and is further separated by gradient elution with an increasing acetonitrile concentration. The two elution stages are synchronized by a computer program. By this system, very complex protein mixtures such as crude cerebellar extracts were resolved reproducibly into ca. 200 peaks within 12 h. The method can be used for the total analysis of proteins in various tissues and cells without complicated premanupulation of samples, and allows the simultaneous analysis of a protein isolated by chromatography. The isolated protein is most suitable for use in the strategy of protein and gene sequence analysis.

Animals↗
PubMed1986

Study on abnormalities in the appearance of finger and palm prints in children with cleft lip, alveolus, and palate.

The aetiology of abnormalities in the appearance of finger and palm prints in children with cleft lip, alveolus, and palate was examined by comparing the frequencies of abnormalities in hereditary cases and sporadic cases, and those in hereditary cases with those in their parents. The following results were obtained: Comparison of hereditary cases and sporadic cases. Abnormalities in the appearance of finger and palm prints were greater in hereditary cases than in sporadic cases. Abnormalities in the appearance of finger and palm prints were greater in parents of hereditary cases than in parents of sporadic cases. The rate of agreement in the appearance of finger and palm prints between parents and children was greater in hereditary cases than in sporadic cases. Comparison within hereditary cases. Abnormalities in the appearance of finger and palm prints were greater in affected children when one of the parents was affected (gamma = 1/2) than when both parents were normal (gamma = less than 1/2). Abnormalities in the appearance of finger and palm prints were greater in parents, one of whom was affected, than in normal parents. The rate of agreement in the appearance of finger and palm prints of parents, one of whom was affected, and their gamma = 1/2 children cases was higher than of normal parents and their gamma = less than 1/2 children. It was concluded that the above results could be explained by multifactorial inheritance.

Adolescent↗
PubMed1985

[Stress pulsed Doppler echocardiography in the evaluation of diastolic left ventricular function].

The effect of sublingual nifedipine on left ventricular (LV) function was assessed by analyzing LV inflow velocity patterns using pulsed Doppler echocardiography (PDE) and radioisotope (RI) angiography in 23 patients with hypertrophic cardiomyopathy (HCM), 13 with hypertensive heart disease (HHD) and 24 with ischemic heart disease (IHD). The results were as follows: LV inflow velocity pattern and M-mode echocardiography after the administration of nifedipine (Study-I). The deceleration time (DT) of the diastolic rapid filling wave was shortened after nifedipine in HCM and HHD, but not in IHD. The acceleration time (AT) of the diastolic rapid filling wave and the A/D ratio (amplitude of an atrial contraction wave/amplitude of a diastolic rapid filling wave) were not significantly changed in all groups. Peak negative Vcf was significantly improved after nifedipine in HCM, but unchanged in the other groups. Fractional shortening and peak Vcf did not change in all groups. LV inflow velocity pattern and RI angiography after nifedipine (Study-II). The mean LV rapid filling rate (V1) based on the LV volume curve by multi-gated blood pool scans increased during nifedipine in HCM and HHD, but other diastolic indices, such as the peak filling rate and 1/3 filling fraction, were unchanged. The DT-V1 relationship during nifedipine shifted toward the right and downward in HCM and HHD. In IHD, however, this relationship shifted toward the left and downward in cases with reduced LV function (V1 less than 1.0 EDC/sec), but toward the right and downward in patients whose LV function was maintained (V1 greater than or equal to 1.0 EDC/sec). Nifedipine therapy was associated with an improved LV filling in nearly all cases of HCM and HHD, and in some cases of IHD. PDE and RI angiography are useful for evaluating LV diastolic function during sublingual nifedipine in various heart diseases.

Cardiomegaly↗
PubMed1985

[Apical mid-diastolic rumble in hypertrophic cardiomyopathy: a pulsed Doppler echocardiographic study].

To investigate the mechanism of an apical mid-diastolic rumble in hypertrophic cardiomyopathy (HCM), we recorded left ventricular (LV) inflow velocity patterns using pulsed Doppler echocardiography and apexcardiography for 10 HCM patients with rumble and 20 HCM patients without rumble. Controls consist of 17 normal subjects, three patients with complete atrioventricular block and two patients with artificial right ventricular pacemakers. The LV inflow velocity profiles were analyzed in terms of acceleration time (AT) and deceleration time (DT) of the rapid filling wave, and the ratio of peak velocity of the atrial contraction wave to that of the rapid filling wave (A/D ratio). The results were as follows: The apical mid-diastolic murmur in HCM had a crescendo-decrescendo character mainly of medium frequency, and increased in intensity after the inhalation of amyl nitrite. All patients with rumble had asymmetric septal hypertrophy and the five of these had LV outflow obstruction. In six of the 10 patients with rumble, mild mitral regurgitation was detected. In HCM with rumble, the AT tended to be shorter than that of HCM without rumble, but it was significantly longer than the AT of normal subjects. In HCM with rumble, the DT was significantly shorter than that of HCM without rumble, but it was significantly longer than the DT of normal subjects. There was no significant difference in the A/D ratio between the HCM with rumble and the normal subjects, but the A/H ratio of the apexcardiogram was significantly increased in HCM with rumble as compared with those of HCM without rumble and of the normal subjects. The LV dimension was significantly decreased in HCM with rumble as compared with those of HCM without rumble and the normal subjects. Peak negative VCF was significantly decreased in HCM with rumble as compared with that of HCM without rumble. But there was no significant difference in this parameter between HCM with rumble and the normal subjects. In simultaneous recordings of apical mid-diastolic rumble and LV inflow velocity patterns, the rumble appeared to start after the beginning of the diastolic rapid filling wave and to stop before or at the end of the diastolic rapid filling wave. In patients with complete atrioventricular block and with artificial right ventricular pacemakers, the apical mid-diastolic rumble appeared when the P wave was during the rapid filling phase of the left ventricle.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

[Mechanism of an early diastolic posterior motion of the interventricular septum in patients with mitral stenosis: with special reference to left ventricular inflow velocity pattern].

The mechanism of an early diastolic posterior motion of the interventricular septum (IVS) was investigated by means of M-mode, two-dimensional and pulsed Doppler echocardiographies in 53 patients with pure mitral stenosis (MS). Velocity patterns of the blood flow at the inflow tract of the left ventricle (LVIT) were classified into three types as previously reported (cf. Fig.3). The results obtained were as follows: The mitral valve orifice area (MVA) was significantly smaller in patients with type III of the LVIT flow velocity pattern than in patients with type I (p less than 0.001). An amplitude ("a") of the posterior IVS motion in systole (P1) was significantly diminished in type III (4.2 +/- 1.1 mm) than in type I (6.6 +/- 1.5 mm) (p less than 0.001). An amplitude ("b") of the posterior IVS motion in early diastole (P3) showed a significant increase in type III (7.5 +/- 1.2 mm) than in type I (5.2 +/- 1.5 mm) (p less than 0.001). Difference of the amplitude between P1 and P3 ("a-b") was significantly greater in type III (-3.4 +/- 1.1 mm) than in type I (1.4 +/- 0.9 mm) (p less than 0.0001). MVA was correlated statistically with "a" (r = 0.58, p less than 0.001), "b" (r = -0.38, p less than 0.01) and "a-b" (r = 0.80, p less than 0.0001). Deformity of the left ventricular cavity due to the flattened IVS in early diastole was observed in severe MS with an augmented septal P3 dip. A case of severe MS with type III velocity pattern and an augmented P3 dip showed type II velocity pattern and a decreased P3 dip after the attack of acute myocardial infarction. These findings suggested a close relationship between type III of the LVIT flow velocity pattern and the prominent septal P3 dip. The importance of diastolic suction of the left ventricle in producing an early diastolic posterior motion of IVS (P3) was discussed.

Biomechanical Phenomena↗
PubMed1984

[Left ventricular function in patients with right ventricular overload evaluated by exercise echocardiography: comparison of pulmonary hypertension and atrial septal defects].

To evaluate left ventricular function in patients (pts) with right ventricular overload, exercise echocardiographic studies using a bicycle ergometer were performed for seven pts with pulmonary hypertension (PH), two with cor pulmonale (CP) and 16 with atrial septal defects (ASD), and the results were compared with those of 10 (control I) and 27 (control II) normal persons. These subjects were categorized in two study groups; study I consisting of PH, CP and control group I with an exercise workload of 25 watts for 3 min; and study II consisting of ASD and control group II with an exercise workload of 50 watts for 3 min. The results were as follows: M-mode echocardiography revealed that: During exercise, the stroke volume (SV) was increased with a significant decrease of left ventricular end-systolic dimension (LVDs), but without a change in left ventricular end-diastolic dimension (LVDd) in control groups I and II, with a marked increase of LVDd and a slight decrease of LVDs in the ASD group. By contrast, the SV in the PH group tended to decrease during exercise with a slight decrease of LVDd, but without a significant change in LVDs. Right ventricular dimension (RVD) was significantly increased during exercise in the PH group, but was decreased in the ASD group. In control groups I and II, RVD did not change during exercise. In ASD, and control groups I and II, the peak velocity of circumferential fiber shortening (Vcf) was increased during exercise, and the peak negative Vcf was significantly decreased. However, these parameters exhibited impaired responses during exercise in the PH group. Abnormal interventricular septal (IVS) motion at rest tended to become normal during exercise in 12 of 16 pts with ASD. In all pts with PH, however, IVS motion did not change substantially during exercise. There were similar parameter responses between the PH and CP groups. Two-dimensional echocardiography showed that: The left ventricular short-axis view demonstrated a diastolic left ventricular configuration which changed from oblique to relatively circular orientation during exercise in the ASD group. In four of five pts with PH, the diastolic configuration of the left ventricle was oblique because of a loss of the normal curvature of the IVS at rest and during exercise. The diastolic left ventricular configuration improved during exercise in only one pt with PH, with slightly elevated pulmonary arterial systolic pressure as in the ASD group.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

[Left ventricular diastolic filling patterns in hypertrophic cardiomyopathy and myocardial infarction: studies by pulsed doppler echocardiography and multi-gated blood pool scans].

Relationship between various parameters of the left ventricular inflow velocity patterns by pulsed Doppler echocardiography and the early diastolic mean filling rate (V1) by multi-gated blood pool scans was evaluated. The materials consist of 26 patients with hypertrophic cardiomyopathy (HCM), 24 with old myocardial infarction (MI), seven with hypertensive heart disease (HHD), seven with dilated cardiomyopathy (DCM), seven with ischemic heart disease (IHD), and 16 normal subjects (N). The results were as follows: 1. Acceleration time (AT) and deceleration time (DT) were significantly prolonged in HCM (120 +/- 20 msec, 147 +/- 23 msec), MI (102 +/- 17 msec, 124 +/- 21 msec), HHD (105 +/- 11 msec, 141 +/- 17 msec) and IHD (111 +/- 16 msec, 122 +/- 20 msec) compared with those of normals (89 +/- 20 msec, 106 +/- 18 msec). 2. V1 was significantly decreased in HCM (1.14 +/- 0.28 sec-1), MI (0.68 +/- 0.24 sec-1), HHD (0.73 +/- 0.12 sec-1), DCM (0.67 +/- 0.30 sec-1) and IHD (1.03 +/- 0.29 sec-1) compared with that of normals (1.48 +/- 0.28 sec-1). 3. There were significant negative correlations between V1 and AT or DT in HCM, IHD with slightly impaired diastolic filling and normals. However, there were significant positive correlations between V1 and AT or DT in MI and DCM. These findings suggested that left ventricular diastolic filling is impaired in both HCM and MI, and that DT-V1 relationship is useful for differentiating HCM characterized by the "chamber stiffness" from MI characterized by the "myocardial stiffness".

Adolescent↗
PubMed1983

[Pulsed Doppler echocardiographic observation of right and left ventricular inflow velocity patterns in various types of arrhythmia, with special reference to the mechanism of atrioventricular regurgitation].

To investigate the possibility for detection of atrio-ventricular (A-V) regurgitation in arrhythmias non-invasively, we recorded velocity patterns of blood flow at the inflow tract of the right (RVI) and left ventricles (LVI), and at the outflow tract of the left ventricle (LVO) by pulsed Doppler echocardiography in 32 patients with various types of arrhythmia. They were six cases with supraventricular premature contraction (SVPC), 13 with ventricular premature contraction (VPC), two with second degree A-V block, five with complete A-V block and six with artificial right ventricular pacemaker. The following results were obtained. In SVPC, peak velocity of the preceding early diastolic flow of RVI and LVI was related to the coupling interval. A crucial ectopic atrial contraction occurring at the early diastole augmented right or left ventricular filling by summation of the two kinds of ventricular filling. Peak velocity of the early diastolic flow at RVI and LVI was decreased after SVPC compared with that of normal sinus rhythm. A reverse flow was not observed in RVI or LVI velocity pattern in these cases. In VPC, peak velocity of the preceding early diastolic flow at RVI and LVI was related to the coupling interval. An effective early diastolic flow was not observed when coupling interval was short. A systolic A-V reverse flow was detected in six of eight cases of VPC with compensatory pause. In these six cases, M-mode and two-dimensional echograms showed patterns of tricuspid and/or mitral valve prolapse and systolic "bulging" of the left ventricular posterior wall. Peak velocity of the blood flow at LVO was decreased in VPCs with short coupling intervals, but it was increased markedly in the next beat after compensatory pause (post-extrasystolic potentiation). Velocity pattern of a blood flow at RVI and LVI showed two types of reverse flow patterns in all cases with complete A-V block or with artificial right ventricular pacemaker; a) systolic reverse flow in beats with P wave superimposed on QRS complex or ST segment, and b) diastolic reverse flow in beats with markedly prolonged P-R intervals. Diastolic tricuspid regurgitation was demonstrated by contrast echography at the level of the tricuspid valve orifice, and diastolic mitral regurgitation by left cineventriculography. The clinical implication of pulsed Doppler echocardiography to detect A-V regurgitation during systole and diastole was discussed in various types of arrhythmia.

Arrhythmias, Cardiac↗
PubMed1983

[Evaluation of left ventricular function in patients with atrial septal defect by exercise echocardiography].

In order to evaluate left ventricular function in atrial septal defect (ASD), 12 cases with ASD, 18 postoperative cases of ASD and 27 normal controls were examined by means of exercise echocardiography using supine bicycle ergometer (50 watts and 3 min). M-mode echocardiograms and left ventricular (LV) short-axis views by two-dimensional echocardiography were subjected to the observation. M-mode echocardiographic studies: ASD group showed an increased stroke dimension (SD) during exercise mainly due to a marked increase of left ventricular end-diastolic dimension ( LVDd ) and a slight decrease of left ventricular end-systolic dimension ( LVDs ). Postoperative ASD group showed an increased SD during exercise mainly due to a marked decrease of LVDs and a slight decrease of LVDd . On the other hand, in normal control group exercise increased SD only by a significant decrease of LVDs . Right ventricular dimension was decreased during exercise in ASD group, but did not change significantly in postoperative ASD and normal control groups. During exercise in ASD group, peak velocity of circumferential fiber shortening (VCF) was increased most markedly, and negative peak VCF was decreased most strikingly. Eight of 12 patients with ASD who showed abnormal interventricular septal motion demonstrated remarkable improvement of the motion during exercise. Two-dimensional echocardiographic studies: Left ventricular short-axis views demonstrated that the shape of the left ventricular cavity changed from flattened to more circular configuration during exercise at end- and early-diastole in ASD group. The shape of the left ventricular cavity at late-systole did not change significantly during exercise in this group. In postoperative ASD group, the left ventricular short-axis view demonstrated circular configuration of the left ventricle at end-diastole both in rest and during exercise. The shape of the left ventricular cavity did not change by exercise. It was concluded that in ASD group cardiac output is increased during exercise by decreasing a left to right shunt at the atrial level and increasing left ventricular filling rate. Therefore, the left ventricular function was found to be good in ASD.

Adolescent↗