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Biomedical subjects

G Takada

Publications and source records attributed to G Takada.

At least 145 records · Page 8Linked to original sources
PubMed1994

Left ventricular preload reserve in preterm infants with patent ductus arteriosus.

The left ventricular Frank-Starling response was studied in 15 preterm infants, less than 1500 g birth weight, and in 16 fullterm infants with patent ductus arteriosus. Left ventricular end diastolic volume (LVEDV), stroke volume, and cardiac output were calculated from biplane echocardiographic images with a modified Simpson's rule, and the left ventricular function curve was obtained by standardising with birth weight and body length. In the relationship between LVEDV and stroke volume, the slope of the regression line was significantly milder in preterm than in fullterm infants; however, there was no significant difference in the relationship between LVEDV and cardiac output. The heart rate was significantly higher in preterm than in fullterm infants. Our data indicated that the premature infants had less left ventricular reserve capacity to respond to the increased preload through the left-to-right ductal shunting than the mature ones, and that the high pulse rate made it possible to generate adequate cardiac output in premature infants.

Cardiac Output↗
PubMed1994

Left ventricular contractile state of early human neonates with patent ductus arteriosus.

Using echocardiographic technique, we studied the left ventricular (LV) contractile state in 32 full-term infants within 24 hr after birth. They were divided into 2 groups based on the timing of the examinations; the group 1 (n = 17), < 3 hr after birth; the group 2 (n = 15), > 3 and < 24 hr after birth, and the additional examinations were performed on day 5. The patency of the ductus arteriosus and its internal diameter were determined by pulsed Doppler and two-dimensional echocardiography. The left atrial to aortic root ratio was obtained from M-mode echocardiography, and the LV contractile state was estimated by the relationship between heart rate-corrected velocity of circumferential fiber shortening (mVcfc) and end-systolic meridional wall stress (ESS). The ductus arteriosus was open in all cases of group 1 and in 83% of the cases of group 2, but the ductal diameter and the left atrial to aortic root ratio significantly decreased in group 2. The relationship between mVcfc and ESS showed no significant differences between 2 groups and the control. Afterload, represented as ESS, was significantly lower in group 1 than the control. We suggest that the low afterload condition helps the adequate LV contraction even under the increased preload through the left-to-right ductus arteriosus shunting after birth.

Blood Flow Velocity↗
PubMed1994

Right ventricular diastolic filling in the first day of life.

To evaluate the effects of altered preload on the Doppler flow pattern of right ventricular inflow in the first day of life, serial Doppler echocardiography of the pulmonary artery (PA) and tricuspid valve was performed in 16 normal neonates at 2, 12, and 24 hr. A computer-interfaced digitizer pad was utilized to measure the followings: PA flow velocity-time integral, total transtricuspid flow velocity-time integral, flow velocity-time integral of early diastolic filling (E area), and flow velocity-time integral of atrial contraction (A area). The PA flow velocity-time integral, total transtricuspid flow velocity-time integral, E area, A area, peak E, and peak A were increased significantly by 24 hr compared with the values at 2 hr of age. However, the peak E/A, E/A area and peak E/total transtricuspid flow velocity-time integral did not show significant changes from 2 to 24 hr. The ductus arteriosus size was inversely correlated with the peak E (r = -0.46, p < 0.05), E area (r = -0.37, P < 0.05), and A area (r = -0.34, p < 0.05). Therefore, the increase in right ventricular preload at 24 hr is considered to be due to the cessation of the left-to-right shunt through the ductus arteriosus. These results suggest that the pattern of early and late diastolic filling of the right ventricle were dependent on the increase in preload. We can therefore conclude that the redistribution of transtricuspid flow induced by the preload condition should be taken into account to interpret the transtricuspid velocity pattern in terms of diastolic function.

Blood Flow Velocity↗
PubMed1994

A preterm infant with secondary carnitine deficiency due to MCT formula--effective treatment of L-carnitine.

We report a preterm infant who was prescribed an MCT formula and subsequently developed carnitine deficiency with liver dysfunction and an elevation of serum CK level. A male infant who had been born at 24 weeks' gestation with birth weight 799 g, was fed with an MCT formula containing 76.8% of all kinds of lipids, because of his steatorrhea after the 30th day. On the 100th day, he was noted hepatomegaly and elevation of serum levels of AST, ALT and CK. The needle biopsy of the liver indicated the existence of the liver damage. He showed low serum carnitine with high urinary loss of acylcarnitine and dicarboxylic aciduria. Administration of L-carnitine was an effective treatment. The carnitine deficiency might be exaggerated by an increased urinary loss of acylcarnitine. We should be cautious of the risk of carnitine deficiency in preterm infants during prolonged use of MCT formula.

Carnitine↗
PubMed1994

A mitochondrial tRNA(Leu)(UUR) mutation at 3,256 associated with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS).

Enzymatic and molecular analyses were conducted on the muscular tissue of a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Significant decreases in activity of complexes I and IV were found and three nucleotide substitutions in the mitochondrial tRNA genes were detected. Two of the substitutions were detected in unaffected members of the family and in some healthy controls. A C-to-T transition mutation at the nucleotide position 3,256 in the mitochondrial tRNA(Leu)(UUR) gene was detected only in the patient and not in unaffected members of the family or 100 healthy controls. The data strongly suggest that this mutation at nucleotide position 3,256 in the mitochondrial tRNA(Leu)(UUR) gene is associated with MELAS.

Adult↗
PubMed1994

Doppler echocardiographic evaluation of left ventricular output and left ventricular diastolic filling changes in the first day of life.

The aim of this study was to evaluate the changes in Doppler transmitral flow patterns during the 1st d of life. Doppler echocardiography of the ascending aorta and mitral valve was performed serially in 20 normal neonates at 2, 12, and 24 h of age. A computer-interfaced digitizer pad was used to measure the following: ascending aorta flow velocity-time integral, total diastolic filling flow velocity-time integral, flow velocity-time integral of early diastolic filling, and flow velocity-time integral of atrial contraction. The inner diameter of the ductus arteriosus was 4.2 +/- 0.6 mm at 2 h of age, 2.3 +/- 0.5 mm at 12 h of age, and had closed in 17 of 20 neonates (85%) by 24 h of age. The ascending aorta flow velocity-time integral and total diastolic filling flow velocity-time integral, which were high at 2 h of age, decreased significantly at 12 h of age [12.2 +/- 2.1 cm versus 9.6 +/- 1.7 cm (p < 0.001) and 8.0 +/- 1.1 versus 7.1 +/- 1.4 (p < 0.01), respectively] but remained constant thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Output↗
PubMed1994

[Asymptomatic hematuria and/or proteinuria in children under 3 years of age: clinicopathological evaluation].

Six boys and six girls aged under 3 years with asymptomatic hematuria and/or proteinuria were found and renal biopsies were performed from 1 month to 10 years after the discovery. Light microscopy uncovered 4 cases of focal segmental glomerulosclerosis (FSGS), 3 cases of diffuse mild mesangial proliferation, and 5 cases of minor glomerular abnormalities. Immunofluorescent studies did not show any significant depositions. Electron microscopy revealed diffuse thinning of the glomerular basement membrane (GBM) in 2 cases, and segmental thinning of the GBM in 8 cases, including 2 cases of FSGS found in the light microscopy. Four cases, including 2 cases of FSGS, had irregular thickening of the GBM and splitting of the lamina densa. Two cases of FSGS did not have GBM abnormalities. The significance of GBM abnormalities in children with asymptomatic hematuria and/or proteinuria under 3 years of age needs to further evaluated.

Age Factors↗
PubMed1993

Mutation of the myelin P0 gene in Charcot-Marie-tooth neuropathy type 1.

We had previously reported that the myelin P0 gene was responsible for Charcot-Marie-Tooth neuropathy type 1B (CMT1B). In this study we found a different mutation of the P0 gene in a family of Charcot-Marie-Tooth neuropathy type 1 without a DNA duplication in chromosome 17p11.2. The mutation, a histidine substitution for arginine at amino acid position 98, is located in the extracellular domain of P0 like as the mutations in the three pedigrees with CMT1B. The extracellular domain forms an immunoglobulin domain responsible for the function of P0 as an adhesion molecule. Alterations in the tertiary structure of the extracellular domain of P0 would modify the function of P0, resulting in an impairment of peripheral myelin compaction.

Adult↗
PubMed1993

Isolation and sequence determination of cDNA encoding human T-protein of the glycine cleavage system.

We present the full-length cDNA sequence of human T-protein of the glycine cleavage system. Overlapping cDNA clones were isolated by screening human liver cDNA libraries with bovine T-protein cDNA. The 1209 base pair open reading frame encodes 403 amino acid precursor protein, and the deduced amino acid sequence of the mature peptide shows 90 and 68% homology to that of bovine and chicken counterpart, respectively. RNA blot analysis of human liver transcripts and Southern blot analysis of human genomic DNA confirm that human T-protein is encoded by a single gene.

Adult↗
PubMed1993

Structure and chromosomal localization of the gene encoding the human myelin protein zero (MPZ).

We describe the cloning, characterization, and chromosomal mapping of the human myelin protein zero (MPZ) gene. The gene is about 7 kb long and consists of six exons corresponding to the functional domains. All exon-intron junction sequences conform to the GT/AG rule. The 5'-flanking region of the gene has a TA-rich element (TATA-like box), two CAAT boxes, and a single defined transcription initiation site detected by the primer extension method. The gene for human MPZ was assigned to chromosome 1q22-q23 by spot blot hybridization of flow-sorted human chromosomes and fluorescence in situ hybridization. The localization of the MPZ gene coincides with the locus for Charcot-Marie-Tooth disease type 1B, determined by linkage analysis.

Base Sequence↗
PubMed1993

Structure and localization of the gene encoding human peripheral myelin protein 2 (PMP2).

Peripheral myelin protein 2 (PMP2) is a small, basic, and cytoplasmic lipid binding protein of peripheral myelin. In this paper, we describe the cloning, characterization, and chromosomal mapping of the human PMP2 gene. The gene is about 8 kb long and consists of four exons. All exon-intron junction sequences conform to the GT/AG rule. The 5'-flanking region of the gene has a TA-rich element (TATA-like box) and a single defined transcription initiation site detected by the primer extension method. The gene for human PMP2 was assigned to chromosome 8q21.3-q22.1 by spot hybridization of flow-sorted human chromosomes and fluorescence in situ hybridization.

Base Sequence↗
PubMed1993

Tissue distribution of mutant mitochondrial DNA in mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS).

We analysed the distribution of mutant mitochondrial DNA (mtDNA) with A-to-G substitution mutation of tRNA(Leu)(UUR) in various autopsied tissues from a patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). There was no significant difference in the proportion (76-86%) of mutant mtDNA in many tissues, except in the lung and spleen. Unequal partitioning of mtDNA in somatic cells appears less prominent than that in germ cells.

Adult↗
PubMed1993

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) decrease in diastolic left ventricular function assessed by echocardiography.

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) are known to be associated with cardiomyopathy. Systolic and diastolic left ventricular functions were assessed by M-mode and Doppler echocardiography in four patients with MELAS and in 14 normal controls. The interventricular septal thickness and left ventricular posterior wall thickness were greater (11.0 +/- 1.6 mm vs. 5.8 +/- 0.7 mm and 11.0 +/- 2.2 mm vs. 5.9 +/- 0.8 mm) in patients with MELAS than in a control group. Parameters of systolic left ventricular functions (ejection fraction, shortening fraction, systolic time intervals, and mean Vcf) and left ventricular dimensions were not significantly different between the two groups. To assess the diastolic function, blood flow velocity across the mitral valve was measured by Doppler echocardiography and various indexes were obtained. In patients with MELAS, the impairment of diastolic left ventricular filling was demonstrated by decrease in the following indexes: peak flow velocity in the early passive filling period (E) (0.76 +/- 0.10 m/s vs. 0.94 +/- 0.09 m/s), integrated velocity for total E (10.2 +/- 1.3 vs. 13.0 +/- 0.9), the ratio of E and late atrial filling integrated velocities (1.72 +/- 0.06 vs. 2.49 +/- 0.29).

Adolescent↗
PubMed1993

A case of fatal infectious mononucleosis presenting with fulminant hepatic failure associated with an extensive CD8-positive lymphocyte infiltration in the liver.

We describe a fatal case of infectious mononucleosis presenting with fulminant hepatic failure associated with extensive CD8-positive lymphocyte infiltration and diffuse karyorrhexis in the liver. Immunohistochemical analysis of mononuclear cells showed that Leu-2a (CD8)-positive lymphocytes were heavily distributed in the portal areas and the sinusoidal spaces, but Leu-3a (CD4)-, Leu-14 (CD22)-, or My 4 (CD14)-positive cells were undetectable in sections of the liver. Southern blot hybridization studies disclosed the presence of Epstein-Barr virus DNA fragments in the liver tissue. The unusual pathologic and immunologic responses observed in this case could not simply be explained by severe Epstein-Barr virus infection. Some superimposed factors should be considered.

CD8 Antigens↗
PubMed1993

Charcot-Marie-Tooth neuropathy type 1B is associated with mutations of the myelin P0 gene.

P0, a major structural protein of peripheral myelin, is a homophilic adhesion molecule and maps to chromosome 1q22-q23, in the region of the locus for Charcot-Marie-Tooth neuropathy type 1B (CMT1B). We have investigated P0 as a candidate gene in two pedigrees with CMT1B and found point mutations which are completely linked with the disease (Z = 5.5, theta = 0). The mutations, glutamate substitution for lysine 96 or aspartate 90, are located in the extracellular domain, which plays a significant role in myelin membrane adhesion. Individuals with CMT1B are heterozygous for the normal allele and the mutant allele. Our results indicate that P0 is a gene responsible for CMT1B.

Alleles↗