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Biomedical subjects

T Baba

Publications and source records attributed to T Baba.

At least 163 records · Page 9Linked to original sources
PubMed1998

Hemodynamic effect of amrinone depends on pretreatment vascular resistance in patients with evolving congestive heart failure: correlation between vascular resistance and neurohormonal activity.

We investigated the hemodynamic effects of amrinone and assessed its effects on neurohormonal factors in 15 patients with evolving congestive heart failure with various origins. We serially determined the pulmonary and systemic vascular-resistance indices after amrinone infusion and examined the relation between changes in hemodynamic parameters and changes in concentrations of norepinephrine, atrial natriuretic peptide, angiotensin II, and endothelin-1 in the pulmonary capillary wedge region (PCWR) and in the peripheral veins. Amrinone significantly reduced pulmonary vascular-resistance index (PVRI; Wood x m2) in patients with high PVRI (> or =15) before the infusion, significantly reduced systemic vascular-resistance index (SVRI; Wood x m2) in patients with high SVRI (> or =50) before the infusion, and had little effect on vascular resistances in patients with low PVRI (<15) and low SVRI (<50). The reduction in PVRI was correlated with the reduction in the endothelin-1 level (r = 0.75) in the PCWR, and the reduction in SVRI with norepinephrine level (r = 0.70) in the peripheral veins. The angiotensin II level did not change throughout the study. These findings suggest that amrinone had selective hemodynamic effects on pulmonary and systemic circulations with neurohormonal effects, according to PVRI and SVRI before infusion.

Aged↗
PubMed1998

Effect of tylosin tartrate on humoral immune responses in chickens.

While many antimicrobial agents have been reported to cause immunosuppression in animals, macrolide antibiotics enhance the immune function. Tylosin tartrate is a macrolide antibiotic approved for the control of mycoplasmosis in poultry. The purpose of this investigation was to determine the effect of tylosin on the humoral immune functions in chickens. Three days after oral tylosin tartrate administration, 4- or 8-week-old chickens were immunized intravenously with carbolic acid-killed Brucella abortus bacterin or sheep red blood cells. Seven days (plasma antibodies titre) or 4 days (antibody forming cells) post-immunization, there was a significant increase in antibody production as well as in the numbers of antibody-producing cells in tylosin tartrate-administered chickens compared with the untreated controls. However, 3 days after tylosin tartrate administration, there was no difference in the distribution of T-lymphocyte subpopulations (CD4 or CD8 positive cells) or B lymphocytes (surface immunoglobulin positive cells) in either the peripheral blood or spleens or untreated control chickens.

Animals↗
PubMed1998

Right parasternal minithoracotomy for repair of atrial septal defect.

Various surgical approaches for repair of atrial septal defect (ASD) have recently been introduced for superior cosmetic and less invasive results. A technique for repair of isolated ASD through a small right parasternal minithoracotomy is described. In spite of the smaller incision, there is no need to use femoral cannulation or video-assisted endoscopy. This approach is simple, less invasive, and cosmetic. We believe that right parasternal minithoracotomy is a suitable alternative to a median sternotomy for ASD closure, especially in young male patients.

Adolescent↗
PubMed1998

Long-term effects of pharmacological therapy for vasovagal syncope on the basis of reproducibility during head-up tilt testing.

The purpose of this study was to determine the efficacy of long-term pharmacological therapy selected on the basis of a head-up tilt test (HUT) in patients in whom reproducibility of the HUT response was demonstrable in the initial study. The HUT (80 degrees upright) was performed for 15 min with or without an infusion of isoproterenol (0.01-0.03 microgram/kg per min) in 54 patients with recurrent unexplained syncope. When vasovagal syncope was induced (positive response), the HUT was repeated to examine the test reproducibility. Vasovagal syncope was induced in 24 patients during HUT alone, and in 30 patients during the HUT with isoproterenol. Acute reproducibility was observed in 49/54 (91%) patients. In the tilt-positive patients, HUT was repeated after an intravenous administration of propranolol (0.1 mg/kg) or disopyramide (1 mg/kg) (acute test). Propranolol proved effective in 21 (80%) of 26 patients, and disopyramide in 13 (56%) of 23 patients. Thereafter, evaluation was done on the long-term clinical follow-up of the pharmacological intervention selected on the basis of the acute test in the 34 patients in whom the HUT could not induce vasovagal syncope after the oral administration of the pharmacological agent (propranolol 60 mg/day, disopyramide 300 mg/day). Thirty-two of 34 patients (94%) did not develop syncopal attacks during a 44 +/- 12-month period. Thus, in patients with unexplained syncope, HUT appears to have a high degree of acute reproducibility, and the acute drug response guided by HUT may be used to develop an effective long-term pharmacological therapy.

Administration, Oral↗
PubMed1998

Decreasing parasympathetic tone activity and proarrhythmic effect after radiofrequency catheter ablation--differences in ablation site.

Holter ECG was used to evaluate changes in heart rate variability (HRV), indicators of the autonomic nervous system, and arrhythmia before and after radiofrequency (RF) catheter ablation in patients with symptomatic supraventricular tachycardia. Ablation targets in 43 patients included the atrioventricular (AV) nodal pathway (AVNRT, n = 17), a right free wall accessory pathway (n = 10), a septal accessory pathway (n = 6), and a left free wall accessory pathway (n = 10). The High frequency component (0.15 - 0.40 Hz) or pNN50 of HRV analysis, indicating parasympathetic activity, significantly decreased immediately after RF ablation in the AVNRT and septal accessory pathway groups, but not in the right or left wall groups. In contrast, in all four groups, ventricular premature contractions (VPCs) significantly increased in most of the patients, and ventricular tachycardia occurred in a few of the patients immediately after RF ablation. There was no serious arrhythmia. These alterations in HRV analysis and arrhythmia returned to the control level after 1 week or more. VPCs after RF ablation did not consistently increase as a result of the reduced parasympathetic tone activity, but at the lesion near the conduction system, the increase in VPCs was inhibited by higher parasympathetic tone activity, because the parasympathetic nerve fibers and receptors were distributed in these lesions.

Adolescent↗
PubMed1998

Slow ventricular tachycardia located in the epicardium of the left ventricular base and characterized by effects of adenosine triphosphate, nicorandil and verapamil.

A 31-year-old male with slow ventricular tachycardia (VT) developed a nonsustained VT with prolongation of the JT intervals after injection of contrast medium and saline into the marginal vein of the coronary sinus. The earliest activation site of the VT existed in the epicardium of the left ventricular base. Adenosine triphosphate prevented induction of VT and prolongation of JT intervals. Ventricular premature contractions showing the same morphology as the VT were also inhibited by nicorandil and verapamil. The mechanism of the VT was suggested to be abnormal automaticity due to an increase in the Ca++ current into cells after prolongation of the action potential duration induced by hypothermia.

Adenosine Triphosphate↗
PubMed1998

Real-time evaluation of the effectiveness of microwave coagulation therapy for hepatocellular carcinoma using color Doppler imaging.

Percutaneous microwave coagulation therapy (PMCT) is a new technique for the treatment of hepatocellular carcinoma (HCC). However, it is difficult to distinguish those lesions in which necrosis has been induced from the viable residual lesions during the procedure, because the margin of the tumor becomes unclear during PMCT. We determined the area of necrotic lesions during the procedure using color Doppler imaging. PMCT was performed on 10 patients (17 lesions) with recurrent HCC. The electrode of the microwave delivery system was moved around the tumor and the surrounding area until color mosaic images disappeared from the entire area of the tumor. The areas in which necrotic tissue was indicated by color Doppler imaging were later confirmed by other modalities such as angiography or contrast-enhanced computed tomography. This leads us to believe that real-time, effective evaluation of PMCT is possible with color Doppler imaging.

Aged↗
PubMed1998

Genomic Analysis of the Genes Encoding Ribosomal Proteins in Eight Eubacterial Species and Saccharomyces cerevisiae.

The complete genomic nucleotide sequence data of more than 10 unicellular organisms have become available. During the past years, we have been focusing our attention to the analysis of the structure and function of the ribosome and its protein components. By making use of the genomic sequence data, our work can now be extended to comparative analysis of the ribosomal components at the genomic level. Such analysis will contribute to our understanding of the structure-function relationship of the ribosome that is vital to the expression of genetic information. Bearing these in mind, the ribosomal protein genes of organisms whose genomic sequence data are available were analyzed, which included Aquifex aeolicus; Archaeoglobus fulgidus; Borrelia burgdorferi; Bacillus subtilis; Escherichia coli; Haemophilus influenzae; Helicobacter pylori; Methanococcus jannaschii; Mycoplasma genitalium; Mycoplasma pneumoniae; Synechosystis sp., and Saccharomyces cerevisiae. In addition, the amino acid sequence data of Bacillus stearothermophilus ribosomal proteins were used in the evolutionary evaluation. The results indicate that, in eubacteria including two species of Mycoplasma, the operon structure of ribosomal protein genes is well conserved, while their relative orientation and chromosomal location are diverged into several classes. The operon structure in M. jannaschii on the other hand is quite different from the eubacterial one and we noticed that its many genes show similarity to rat ribosomal protein genes. The degrees of sequence conservation differ from one ribosomal protein gene to another, but several genes encoding proteins that are considered to be of structural importance are conserved throughout the bacterial species including archaebacteria and further in S. cerevisiae.

Journal Article↗
PubMed1998

MR of denervated tongue: temporal changes after radical neck dissection.

PURPOSE: The purpose of this study was to evaluate the temporal changes of MR imaging in the denervated tongue after a radical neck dissection. METHODS: One hundred seventy-four consecutive MR studies in 116 patients with radical neck dissections for malignant tumors of the head and neck were evaluated retrospectively. Patients with tumors involving the tongue or hypoglossal nerve were not included in this study. RESULTS: Abnormal signal intensity and/or hemiatrophy on the side of the tongue operated on was seen in 22 patients who had hypoglossal paralysis after radical neck dissection. The denervated side of the tongue appeared hypointense to hyperintense relative to the normal side on T1-weighted images and hyperintense on T2-weighted images. Signal intensity ratios of the abnormal to normal muscles were 0.9-1.6 on T1-weighted images and 1.3-2.8 on T2-weighted images. High signal intensity on T1-weighted images appeared 5 months or more after the dissection, whereas on T2-weighted images, the most prominent increases in signal intensity appeared in the first several months after denervation. Hemiatrophy of the tongue was observed on MR images obtained more than 6 months after surgery. CONCLUSION: MR findings in the denervated tongue are compatible with histologic changes and are characterized by an enlarged extracellular fluid space or fatty infiltration. The pattern of signal intensity and the degree of hemiatrophy suggest the duration of denervation.

Adult↗
PubMed1998

MR sialography using half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences.

We describe our preliminary experience with the half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences for MR imaging of the salivary gland ducts. In the majority of patients, the main parotid and/or submandibular gland ducts and large branches within the glands were detectable on MR images obtained in 2 seconds per section and within 3 minutes for the entire examination. MR sialography using HASTE sequences can be combined with conventional MR studies for the salivary glands.

Adult↗
PubMed1998

[A case of primary cardiac malignant fibrous histiocytoma].

In this article, we report a case of primary cardiac malignant fibrous histiocytoma. The patient, 74-year-old female, had been treated medically for heart failure with minimal improvement and was referred to our hospital. Echocardiogram revealed two cardiac tumors in the left atrium, one of which was obstructing the inflow of the mitral valve. Emergent surgical resection was performed successfully with shortterm ICU stay, but the patient died of DIC on the 24th day after surgery. The pathological examination revealed malignant fibrous histiocytoma and this report is the 40th case report of this kind of primary cardiac tumor.

Aged↗
PubMed1997

MR evaluation of radiation otomastoiditis.

PURPOSE: The purpose of this study was to evaluate the incidence of radiation otomastoiditis, on using T2-weighted magnetic resonance (MR) imaging, in relation to radiation fields, doses, intervals, and clinical symptoms after radiotherapy that included the temporal bone in the fields. METHODS AND MATERIALS: We performed follow-up MR examinations at various intervals after radiotherapy including the temporal bones for 270 ears of 114 patients with various diseases of the head and neck and intracranial regions. The middle ear and mastoid air cells on T2-weighted images were scored as follows; showing no high signal intensity, a local high signal intensity area, or a high signal intensity area occupying the entire middle ear and all mastoid air cells. The radiation fields as depicted on the lateral simulator films classed as anterior to the clival line, posterior to the clival line, or both. RESULTS: The incidence of radiation otomastoiditis depicted on T2-weighted MR images increased in the patients who had received irradiation doses of 50 Gy or more. In the patients with doses of less than 50 Gy, the incidence was 18% within 6 months following radiotherapy, 13% at between 6 and 12 months, and 8% after 12 months, whereas it was more than 50% at any period after radiotherapy in the patients with 50 Gy or more. The incidence of radiation otomastoiditis was quite high in the patients whose radiation fields included region both anterior and posterior to the clival line. CONCLUSION: The incidence of radiation otomastoiditis as demonstrated on T2-weighted MR images is increased at irradiation doses of 50 Gy or more. To reduce the incidence of severe radiation otomastoiditis, the irradiation fields of the temporal bone when the dose is 50 Gy or more should be limited to as small as possible. The clival line is considered to be a good landmark in reducing the irradiation field when doses of 60-70 Gy are delivered in curative radiotherapy.

Adolescent↗
PubMed1997

Identification of likely genes on chromosome VI of Saccharomyces cerevisiae by correlating transcripts and nucleotide sequence data.

Most of the 97 transcripts of the genes on chromosome VI of Saccharomyces cerevisiae that were identified by a series of Northern hybridization experiments (Yoshikawa and Isono, Nucl. Acids Res., 19, 1189-1195, 1991) have been correlated with the open reading frames (ORFs) deduced from the nucleotide sequence data of this chromosome (Murakami et al., Nature Genet., 10, 261-268, 1995). This was performed by comparing the experimentally constructed physical map and the one produced from the nucleotide sequence data, as well as the sizes and positions of observed transcripts and those of sequenced ORFs. Thus, 75 ORFs of chromosome VI were correlated uniquely with the corresponding transcripts and 3 ORFs with two transcripts of different sizes. Comparing the relative abundance levels of individual transcripts with that of the RPO41 transcript, highly expressed genes of chromosome VI were found to be located almost exclusively on the Crick strand. Based on the correlation between the abundance level of the experimentally identified transcripts and the codon adaptation indices of the corresponding gene, the genes on chromosome VI of S. cerevisiae were classified into three groups. The data thus provides information concerning their chromosomal locations as well as their likely levels of expression in vegetatively growing cells.

Chromosome Mapping↗
PubMed1997

Construction of a contiguous 874-kb sequence of the Escherichia coli -K12 genome corresponding to 50.0-68.8 min on the linkage map and analysis of its sequence features.

The contiguous 874.423 base pair sequence corresponding to the 50.0-68.8 min region on the genetic map of the Escherichia coli K-12 (W3110) was constructed by the determination of DNA sequences in the 50.0-57.9 min region (360 kb) and two large (100 kb in all) and five short gaps in the 57.9-68.8 min region whose sequences had been registered in the DNA databases. We analyzed its sequence features and found that this region contained at least 894 potential open reading frames (ORFs), of which 346 (38.7%) were previously reported, 158 (17.7%) were homologous to other known genes, 232 (26.0%) were identical or similar to hypothetical genes registered in databases, and the remaining 158 (17.7%) showed no significant similarity to any other genes. A homology search of the ORFs also identified several new gene clusters. Those include two clusters of fimbrial genes, a gene cluster of three genes encoding homologues of the human long chain fatty acid degradation enzyme complex in the mitochondrial membrane, a cluster of at least nine genes involved in the utilization of ethanolamine, a cluster of the secondary set of 11 hyc genes participating in the formate hydrogenlyase reaction and a cluster of five genes coding for the homologues of degradation enzymes for aromatic hydrocarbons in Pseudomonas putida. We also noted a variety of novel genes, including two ORFs, which were homologous to the putative genes encoding xanthine dehydrogenase in the fly and a protein responsible for axonal guidance and outgrowth of the rat, mouse and nematode. An isoleucine tRNA gene, designated ileY, was also newly identified at 60.0 min.

Base Sequence↗
PubMed1997

New assay for glycated lipoproteins by high-performance liquid chromatography.

We developed an automated analytic system for glycated lipoprotein using high-performance liquid chromatography (HPLC) with an affinity boronate column and a gel permeation column. This system can measure glycated lipoprotein (glycated LDL and glycated HDL) in a small (5 microliters) sample of serum in a short time (40 min/sample). Recovery with this system was 92.1%. Therefore a large number of samples can be measured in clinical use. The system should contribute to an elucidation of the role of glycated lipoprotein in atherosclerosis.

Chromatography, High Pressure Liquid↗