Biomedical subjects

F Saito

Publications and source records attributed to F Saito.

At least 73 records · Page 4Linked to original sources

PubMed1995

[A surgical treatment of ruptured aortic dissection with non-opacified false lumen].

A 63-year-old woman was admitted to our intensive care unit suffering from severe chest pain and shock. Emergency CT scan demonstrated an acute type A aortic dissection with non-opacified false lumen and cardiac tamponade. The aortography showed ulcer like projection at the ascending aorta. An emergency operation was performed to replace the ascending aorta with a woven double-velour Dacron graft of 30 mm in diameter. It seems that an acute type A aortic dissection with non-opacified false lumen has good prognosis. The presence of other complications, however, suggests that surgical treatment should be decided upon at an early stage.

Aortic Dissection↗

PubMed1995

[A case of reoperation of Ebstein's anomaly with increased tricuspid regurgitation after Hardy's operation].

A 30-year-old man, who had undergone Hardy's operation and the direct closure of an atrial septal defect for Ebstein's anomaly at age 9, was reoperated on by Carpentier's procedure for a long-standing tricuspid regurgitation. He required IABP support to wean from the cardiopulmonary bypass for the acute heart failure. Nonetheless, his postoperative course was uneventful. Echocardiography, nine months after the operation, showed a decrease in moderate residual regurgitation and an increase in the right ventricular inflow velocity, which were considered signs of an improvement in the right ventricular function and, furthermore, it showed an increase in the left ventricular volume and a marked improvement in the left ventricular ejection fraction. We consider that tricuspid regurgitation for many years result in a dysfunction in the right ventricle and, because of a decrease in the filling volume, in the left ventricle. For this reason, we should positively perform an operation without leaving tricuspid regurgitation as it is.

Adult↗

PubMed1994

Direct mapping of the human TATA box-binding protein (TBP) gene to 6q27 by fluorescence in situ hybridization.

TBP (TATA box-binding protein) participates in the expression of eukaryotic genes transcribed by RNA polymerases I, II, and III. Molecular cloning of human TBP revealed that the N-terminal region contains a polymorphic (CAG)n repeat. We report here the direct localization of human TBP gene to chromosome 6q2705-->qter region by fluorescence in situ hybridization, using the cDNA clone with or without the (CAG)n repeat as a probe.

Chromosome Mapping↗

PubMed1994

Biodegradation and toxicity to fish of di-long-chain tertiary amine salt containing ester and amide bonds.

Biodegradability of N-(3-alkanoylaminopropyl)-N-(2-alkanoyloxyethyl)-N- methylammonium chloride (EAA) was investigated. Biodegradabilities by biochemical oxygen demand (BOD) and dissolved organic carbon (DOC) after 28 days were 79 and 91%, respectively, and almost the same amount of ammonium ion as the theoretical value was detected using a modified MITI test (I) (OECD guidelines, 301C). In the test with activated sludge obtained from a municipal sewage treatment plant, biodegradabilities by BOD and DOC after 35 days were 87 and 98%, respectively, and the 1H-NMR analysis of the tested solution which was done separately under similar conditions indicated the rise and fall of two biodegradation intermediates. Therefore, EEA was considered to be a readily and ultimately biodegradable compound. Besides, the 96-hr LC50 value in red killifish (Oryzias latipes) of EAA was 66 mg/liter. More than 1000 mg/liter was of biodegradation intermediates rapidly made by biodegradation of EAA. These results reveal that EAA has sufficient environmental compatibility.

Animals↗

PubMed1994

Developmental changes of sialylation of soluble beta/A4 amyloid protein precursor derivatives in human cerebrospinal fluid.

Soluble beta/A4 amyloid protein precursor derivatives (APPs) in cerebrospinal fluid from infants, children, adults and aged individuals were treated with neuraminidase. In the samples from infants, reduction of molecular weight of APPs following neuraminidase treatment was significantly less than those from adults or aged individuals. Hyposialylation of beta/A4 amyloid protein precursor in infants may be relevant to a physiological role of this molecule in the development of the nervous system.

Adult↗

PubMed1994

Duration and extent of antianginal effects of a sustained-release formulation of nifedipine in angina.

Twenty-four patients with chronic stable exertional angina pectoris were randomized in a double-blind, placebo-controlled, crossover trial to assess the efficacy and durability of a newly developed, sustained-release formulation of nifedipine (nifedipine CC) in a single 40-mg oral dose. Symptom-limited graded treadmill exercise tests were performed just before, and at 4, 7, and 24 h after a single administration of the drug or the placebo was given. Exercise tolerance at 4, 7, and 24 h after the drug were compared with the corresponding placebo values. Data could be analysed for 19 patients. Maximal exercise time, time to the onset of angina, and time to 1 mm ST segment placebo. The average maximal exercise time was significantly increased by 72, 76, and 37 s at 4, 7, and 24 h. Rate-pressure product at rest and at peak exercise showed significant changes only at 24 h compared with placebo (both P < 0.05). The maximal increase in exercise tolerance was most marked at 7 h nifedipine CC, at which time plasma drug concentration was 99.4 +/- 14.0 ng.ml-1. Thus, in patients with chronic stable exertional angina pectoris, nifedipine CC showed a prolonged improvement in exercise tolerance up to 24 h after a single oral administration.

Angina Pectoris↗

PubMed1994

Entire nucleotide sequence for Bacillus brevis Nagano Grs2 gene encoding gramicidin S synthetase 2: a multifunctional peptide synthetase.

Bacillus brevis Nagano grs2 gene, which encodes gramicidin S synthetase 2 (GS2) catalyzing activation and combination of four constituent amino acids of gramicidin S, namely, proline, valine, ornithine, and leucine, has been sequenced. The open reading frame of grs2 gene specifies a 4,450-amino acid protein with a calculated molecular weight of 508,658. There are four domains with a mean of 1,042 amino acid residues containing a repeated sequence of about 600 amino acids, which is highly homologous to the amino-terminal half of gramicidin S synthetase 1 (GS1) (about 40-50% identity). Three domains of grs2 protein, excluding the first one, show homology over the entire sequences of 1,042 amino acids, but the first domain only shows homology in the conserved 600-amino acid sequence. The last 300-amino acid sequence of grs2 protein following the fourt domain has no homology with any of the above sequences. Translation products of subcloned fragments containing the third or the fourth domain catalyzed ornithine- or leucine-dependent ATP-32Pi exchange, respectively. These results, together with a previous report on a proline-activation domain indicated that the repeated and conserved domains are the individual activation sites of the constituent amino acids; the activation sites are arranged in the order of peptide elongation on GS2. Several motifs of grs2 protein are conserved among the multiple domains of peptide synthetases and aminoacyl or acyl adenylate-forming enzymes.

Amino Acid Isomerases↗

PubMed1994

Mutant genes of gramicidin S synthetase 1 defective in phenylalanine racemization have the same sequence as the wild gene.

Mutant grs1 genes were cloned and sequenced from the Bacillus brevis Nagano BI-4, C-3, E-1, and E-2 strains, which produce defective gramicidin S synthetase 1 (GS1), lacking racemase activity. Surprisingly, these mutant genes had entirely the same sequence as that of the wild type gene. These mutant strains also produce defective gramicidin S synthetase 2 (GS2), lacking 4'-phosphopantetheine, a prosthetic group of this enzyme. The participation of this group in phenylalanine racemization is suggested.

Amino Acid Isomerases↗

PubMed1994

Neuropathology of late cortical cerebellar atrophy in Japan: distribution of cerebellar change on an autopsy case and review of Japanese cases.

We report a Japanese autopsy case of late cortical cerebellar atrophy. The patient had showed clinically transient remission during thyrotropin-releasing hormone therapy. Our case suggests that thyrotropin-releasing hormone therapy is worth trying as a treatment of late cortical cerebellar atrophy. Neuropathological examination showed diffuse cerebellar cortical lesions and absence of neuronal loss in the dorsomedial part of the inferior olives. We studied qualitatively the detailed distribution of the cerebellar cortical lesions in 6 sections of the right cerebellum. The cerebellar lesions were more conspicuous in the most lateral hemisphere than in the vermis. We also reviewed 7 Japanese autopsy cases of late cortical cerebellar atrophy.

Aged↗

PubMed1994

Kinins contribute to the improvement of insulin sensitivity during treatment with angiotensin converting enzyme inhibitor.

Although angiotensin converting enzyme inhibitors and alpha 1-blockers have been reported to improve insulin sensitivity, their mechanisms of action have not been elucidated. To investigate the role of kinins in insulin sensitivity, we treated 4-week-old spontaneously hypertensive rats with either an angiotensin converting enzyme inhibitor (enalapril), an alpha 1-blocker (doxazosin), or an angiotensin II antagonist (losartan) for 3 weeks. A control group received no drugs. In addition, 18 rats treated with enalapril or doxazosin received a simultaneous administration of a kinin antagonist (Hoe 140). Glucose clamp testing was performed in each group. Enalapril (128 +/- 1 mmHg) and doxazosin (132 +/- 2 mmHg) decreased mean blood pressure compared with control levels (148 +/- 1 mmHg) (P < .01). The glucose requirement for the clamp test during the administration of enalapril (25.8 +/- 0.5 mg/kg per minute) or doxazosin (28.6 +/- 0.7 mg/kg per minute) was higher than that of the control group (19.8 +/- 0.5 mg/kg per minute) (P < .05). Although Hoe 140 did not alter the glucose requirement of doxazosin (27.8 +/- 0.5 mg/kg per minute), it decreased that of enalapril (22.6 +/- 0.9 mg/kg per minute) (P < .05) without affecting the changes in mean blood pressure induced by enalapril. In addition, losartan decreased mean blood pressure but did not affect the glucose requirement. Thus, the improvement in insulin sensitivity produced by an angiotensin converting enzyme inhibitor is mostly dependent on kinins but not on angiotensin II antagonism, and an alpha 1-blocker improves insulin sensitivity irrespective of kinins.

Analysis of Variance↗

PubMed1994

Cloning, characterization, and chromosomal mapping of human aquaporin of collecting duct.

We recently cloned a cDNA of the collecting duct apical membrane water channel of rat kidney, which is important for the formation of concentrated urine (Fushima, K., S. Uchida, Y. Hara, Y. Hirata, F. Marumo, and S. Sasaki. 1993. Nature [Lond.]. 361:549-552). Since urine concentrating ability varies among mammalian species, we examined whether an homologous protein is present in human kidney. By screening a human kidney cDNA library, we isolated a cDNA clone, designated human aquaporin of collecting duct (hAQP-CD), that encodes a 271-amino acid protein with 91% identity to rat AQP-CD. mRNA expression of hAQP-CD was predominant in the kidney medulla compared with the cortex, immunohistochemical staining of hAQP-CD was observed only in the collecting duct cells, and the staining was dominant in the apical domain. Functional expression study in Xenopus oocytes confirmed that hAQP-CD worked as a water channel. Western blot analysis of human kidney medulla indicated that the molecular mass of hAQP-CD is 29 kD, which is the same mass expected from the amino acid sequence. Chromosomal mapping of the hAQP-CD gene assigned its location to chromosome 12q13. These results could be important for future studies of the pathophysiology of human urinary concentration mechanisms in normal and abnormal states.

Amino Acid Sequence↗

PubMed1994

[A study of the mechanism of action of BCG against transitional cell carcinoma of the bladder--the change of TNF-alpha and IL-2 in the serum and urine].

To study the mechanism of action of BCG against transitional cell carcinoma of the bladder from the immunological standpoint, we observed time-course changes in the serum and urine levels of tumor necrosis factor (TNF-alpha) and interleukin-2 (IL-2) before and after an intravesical BCG instillation in 16 patients with superficialis transitional cell carcinoma. Serum TNF-alpha concentrations were roughly constant and lower than normal though there was a slight difference between the values before and after BCG instillation or between the test and control values. TNF alpha secretion in urine was increased irrespective of the time for sampling specimens as compared with the control values sampling, remained unaffected by BCG instillations and was increased in many patients even before BCG instillation, probably due to presence of vesical inflammation. No significant changes were detected regarding serum or urine IL-2 before and after BCG instillation and between the test and control values. Thus, the present study failed to demonstrate the involvement of a direct action of TNF-alpha, activation of immunological cells by IL-2 or its direct action as an anti-tumor effect of intravesical instillation of BCG.

Administration, Intravesical↗

PubMed1994

[Acute relapsing ataxic polyradiculoneuritis following respiratory tract infections].

We report a patient with a relapsing form of acute ataxic polyradiculoneuritis. The patient developed marked sensory ataxia with mild limb weakness following a respiratory tract infection. Five similar relapses occurred over 18 years. The symptoms reached their maximum in 2 weeks, followed by subsequent gradual improvement over 1-2 months. Sural nerve biopsy showed mild loss of large myelinated fibers.

Acute Disease↗

PubMed1994

[Changes in left ventricular pressure volume loop of Lutembacher syndrome].

A 49-year-old woman with Lutembacher syndrome, atrial septal defect (ASD), mitral stenosis (MS), tricuspid regurgitation and cardiac cachexia underwent a mitral valve replacement with a 27 mm CarboMedics valve, patch closure of ASD and tricuspid annuloplasty to 29 mm by DeVega's method. The pressure volume loop (PV loop) was measured, both preoperatively and postoperatively (immediately and two months after the operation) by a Miller catheter and echocardiogram. The left ventricular stroke work (LVSW), left ventricular end diastolic volume (LVEDV) and left ventricular end diastolic pressure (LVEDP) markedly increased immediately after the operation. LVSW and LVEDV further increased, whereas LVEDP decreased with improvements in diastolic compliance two months after the operation. It was likely that those change of LV function was a sum of simple ASD and MS both of which have similar but less significant characters than Lutembacher syndrome.

Cachexia↗

PubMed1993

Median method for detecting endogenous event-related brain potentials.

Most studies of event-related brain potentials (ERPs) use the averaging method. This procedure is assumed to increase signal/noise ratio in proportion to the square root of the number of trials if the signal is invariant and the noise is stationary. In addition, the averaged value is the appropriate measure of central tendency if the measurements have a Gaussian distribution. For endogenous ERPs, however, application of the averaging method encounters 3 serious problems. First, the invariance of signal cannot always be assumed because the endogenous signal reflects psychological processes which may be missing in some trials. Secondly, the Gaussian distribution cannot be assumed when a small number of trials is averaged. Thirdly, averaging a limited number of trials is sensitive to inclusion of occasional, non-random, noise. The characteristics of the median ERP can address all 3 problems. These characteristics are demonstrated by an original equation.

Brain↗

PubMed1993

Escape from in vitro aging in SV40 large T antigen-transformed human diploid cells: a key event responsible for immortalization occurs during crisis.

A human diploid fibroblast strain MRC-5 was transfected with a replication origin-defective early region of SV40 containing the gene of large T antigen, and 48 clones of T antigen-transformed MRC-5 were isolated. Although T antigen prolonged the lifespan of MRC-5, all the transformed clones were still mortal. From two of the transformed MRC-5 clones, eight independent immortalized clones were obtained in triple experiments of immortalization. The transformed phenotypes of immortalized clones were widely varied and did not always retain those of the parental pre-immortalized clones. The immortalization occurred at the frequency of about 1-3 x 10(-7)/cell. From cell number and population doubling time of the immortalized clones, the immortalization was estimated to occur in or just before the crisis of parental mortal cells. The decreases of modal chromosome numbers and the loss of chromosomes 5 and 10 were found to be common in three independent immortalized clones examined. Thus, the escape from the cellular aging process seemed to be caused by certain genetic events including the loss of chromosomes at the end of lifespan in T antigen-transformed human diploid cells.

Aneuploidy↗

PubMed1993

Soluble derivatives of beta/A4 amyloid protein precursor in human cerebrospinal fluid are both N- and O-glycosylated.

The linkage of the glycan chain to the beta/A4 amyloid protein precursor (APP) in cerebrospinal fluid (CSF) was studied by Western blot analysis. The apparent molecular weight of APP in CSF was reduced from 103 to 100 kDa by N-glycanase, and to 96 kDa by O-glycanase treatment, respectively. These data indicate that APP is both N- and O-glycosylated in one molecule. The extent of glycosylation of APP was not altered in the CSF from patients with Alzheimer's disease.

Adult↗

PubMed1993

Insulin attenuates agonist-mediated calcium mobilization in cultured rat vascular smooth muscle cells.

Insulin has been shown to attenuate pressor-induced vascular contraction, but the mechanism for this vasodilatory action is unknown. This study examines the effect of insulin on angiotensin II (ANG II)-induced increments in cytosolic calcium in cultured rat vascular smooth muscle cells (VSMC). 20-min incubations with insulin (10 microU/ml to 100 mU/ml) did not alter basal intracellular calcium concentration ([Ca2+]i), but inhibited the response to 100 nM ANG II in a dose-dependent manner (ANG II alone, 721 +/- 54 vs. ANG II + 100 mU/ml insulin, 315 +/- 35 nM, P < 0.01). A similar effect of insulin on ANG II action was observed in calcium poor buffer. Moreover, insulin did not effect calcium influx. ANG II receptor density and affinity were not affected by 24-h incubation with insulin. To further clarify the mechanisms of these observations, we measured ANG II-induced production of inositol 1,4,5-triphosphate (IP3), and IP3-releasable 45Ca. Insulin treatment did not alter ANG II-stimulated IP3 production. However, IP3-stimulated release of 45Ca in digitonin permeabilized cells was significantly reduced after 5-min incubations with 100 mU/ml insulin. Thapsigargin induced release of calcium stores was also blocked by insulin. Thus, insulin attenuates ANG II-stimulated [Ca2+]i primarily by altering IP3-releasable calcium stores. Insulin effects on ANG II-induced [Ca2+]i were mimicked by preincubation of VSMC with either sodium nitroprusside or 8-bromo-cGMP. As elevations in cGMP in vascular tissue lower [Ca2+]i, it is possible that insulin affects IP3 release of calcium by a cGMP-dependent mechanism that would contribute to its vasodilatory effects.

Angiotensin II↗