Biomedical subjects

H Akutsu

Publications and source records attributed to H Akutsu.

At least 37 records · Page 2Linked to original sources

PubMed2000

Concentrative relationship between polymorphonuclear elastase and urinary trypsin inhibitor in amniotic fluid.

In the amniotic fluid, urinary trypsin inhibitor (UTI) seems to inhibit polymorphonuclear elastase (PMNE) activity. The PMNE and UTI concentrations in normal amniotic fluid at 16-20 and 38-40 gestational weeks were measured. The PMNE concentration increased significantly at 38-40 weeks, whereas UTI concentration decreased significantly. According to concentrative relationships between both substances, PMNE may be activated more at the full term pregnancy. Since PMNE-induced tissue injury potentially causes degradation of amniotic collagen, the present result suggests that the quotient of PMNE and UTI concentrations is a reliable index to estimate the occurrence of rupture of the membranes.

Abortion, Induced↗

PubMed2000

Distal superior cerebellar artery aneurysm in a patient with systemic lupus erythematosus: case report.

BACKGROUND: The authors describe a case of ruptured distal superior cerebellar artery (SCA) aneurysm in a patient with systemic lupus erythematosus (SLE). CASE DESCRIPTION: A 31-year-old female who had been treated for SLE for 13 years presented with a subarachnoid hemorrhage. Cerebral angiography demonstrated an aneurysm arising from the cisternal portion of the left superior cerebellar artery. The patient underwent early endovascular coil embolization and was discharged from our hospital without neurological deficit. CONCLUSION: Aneurysms arising from peripheral segments of cerebellar arteries are rare, and delayed surgical clipping has been recommended for these lesions. In addition, the outcomes of SLE patients with ruptured cerebral aneurysms are reported to be very poor due to the systemic complications of SLE. However, our patient had a favorable outcome with early endovascular treatment for the ruptured aneurysm and with appropriate medical treatment for the accompanying SLE. Therefore, early endovascular coil embolization is worthy of consideration among the options for therapeutic intervention in these conditions.

Adult↗

PubMed2000

The influence of left ventricular geometry on coronary vasomotion in patients with essential hypertension.

The objective of this study was to assess the influence of left ventricular (LV) geometric pattern on coronary vasomotion in patients with essential hypertension. We studied 34 hypertensive patients, who had never been treated, with angiographically normal coronary arteries. Patients were classified into four LV geometric patterns by echocardiography: normal, concentric remodeling, eccentric hypertrophy, and concentric hypertrophy. The responses of coronary vasomotion in left anterior descending artery to vasoactive agents (acetylcholine, isosorbide dinitrate, adenosine triphosphate) were examined using a Doppler guidewire and quantitative coronary angiography. The percent increase in coronary blood flow evoked with acetylcholine (endothelium-dependent vasomotion) showed lowest in concentric hypertrophy, followed by eccentric hypertrophy, concentric remodeling, and normal geometry. The significant linear relationship between acetylcholine-induced coronary blood flow and LV mass was noted. There was no difference in the percent increase in coronary blood flow evoked with isosorbide dinitrate (endothelium-independent vasomotion of conduit vessel) among the four groups. The percent increase in coronary blood flow evoked with adenosine triphosphate (endothelium-independent vasomotion of resistant vessel) was significantly lower in patients with concentric hypertrophy than in the other three groups. The results in this study suggest that coronary vasomotion may be associated with LV geometry in patients with hypertension. The endothelium-dependent vasodilation is impaired progressively as LV hypertrophy advances. The endothelium-independent vasodilation of microvessels is impaired only in concentric hypertrophy. This advanced abnormality of coronary vasomotion may contribute to the high cardiovascular morbidity and mortality in patients with concentric hypertrophy.

Acetylcholine↗

PubMed2000

The tissue distribution of lidocaine in acute death due to overdosing.

A 78-year-old woman committed double suicide with a bolus injection of 1 g of lidocaine hydrochloride. The tissue distribution of lidocaine in this fatal poisoning was investigated using an improved gas chromatographic method. The blood level was 42 microg/ml and the brain concentration was 70 miccro/g. Thus, the cause of death in this case was clearly diagnosed as lidocaine overdosing. The blood level of 42 microg/ml was higher than that calculated using the standard pharmacokinetic parameters. Lower blood/tissue ratios were also detected compared with the data described in the literature. These results indicated that the cardiac failure should have occurred immediately after the lidocaine injection. The present data show the distribution of lidocaine after acute death due to overdosing.

Journal Article↗

PubMed2000

Further evidence that sperm nuclear proteins are necessary for embryogenesis.

We have recently presented evidence that the structural integrity of the mouse sperm nuclear matrix may be necessary for the proper unpackaging of sperm DNA for participation in embryogenesis. It is likely that the sperm nuclear matrix contributes to the organisation of the sperm DNA and its disturbance can seriously damage the paternal genome or its expression. In this work, we confirm our previous data and further suggest that even very subtle changes in the sperm nuclear structure may have a significant impact on embryo development. As reported previously, dithiothreitol (DTT) in the presence of an ionic detergent, ATAB, destabilized the nuclear matrix as measured by the halo assay, and oocytes injected with these nuclei failed to develop. We also discovered that omitting the protease inhibitor PMSF from the buffers used to extract spermatozoa prevented sperm injected into oocytes from participating in development. The organization of DNA into loop domains by the nuclear matrix in these nuclei appeared normal, as measured by the halo assay. Oocytes injected with sperm nuclei that had been washed with ATAB in the presence of phenylmethylsulphonyl fluoride (PMSF) but in the absence of DTT resulted in live births. Neither DTT treatment nor the absence of PMSF would be expected to disrupt the integrity of the paternal DNA. The data therefore suggest that even very subtle alterations in the structural proteins of the nucleus are enough to deprive sperm DNA of the ability to contribute to embryonic development.

Animals↗

PubMed2000

Recognition thresholds for letters with simulated dioptric blur.

We examined the effects of simulated dioptric blur on the degradation of visual acuity using digitally filtered letters. Four types of digital filters were applied to 5 letters (C, D, E, O, and S), constructed to the specifications of Sloan optotypes. These filters were: (1) "normal," designed to simulate the positive and negative lobes of the modulation transfer function (MTF) produced by dioptric blur; (2) "truncated," which passed only those spatial frequencies up to the first zero of the MTF; (3) "phase-rectified," which inverted all of the negative lobes of the MTF to positive; and (4) "truncated-plus-negative," which eliminated all positive lobes above the first zero of the MTF. The letter size required to achieve 60%-correct identification was determined for letters that were filtered to simulate +1, +2, and +4 D of blur. Letters subjected to normal, truncated, and truncated-plus-negative filtering had approximately the same acuity threshold, whereas the threshold size for phase-rectified letters was significantly better. Our interpretation of these results is that dioptric blur hinders letter recognition because useful spatial frequency information is limited to that below the first zero of the MTF, and not because of interference from the phase-reversed spatial frequency information above the first zero. Our letter identification thresholds are consistent with recent evidence that the critical information for letter acuity corresponds to approximately 1.5 cycles/letter.

Adult↗

PubMed2000

Amyloid protofilament formation of hen egg lysozyme in highly concentrated ethanol solution.

Mutant human lysozymes (Ile56Thr & Asp67His) have been reported to form amyloid deposits in the viscera. From the standpoint of understanding the mechanism of amyloid formation, we searched for conditions of amyloid formation in vitro using hen egg lysozyme, which has been extensively studied from a physicochemical standpoint. It was found that the circular dichroism spectra in the far-ultraviolet region of the hen egg lysozyme changed to those characteristic of a beta-structure from the native alpha-helix rich spectrum in 90% ethanol solution. When the concentration of protein was increased to 10 mg/mL, the protein solution formed a gel in the presence of 90% ethanol, and precipitated on further addition of 10 mM NaCl. The precipitates were examined by electron microscopy, their ability to bind Congo red, and X-ray diffraction to determine whether amyloid fibrils were formed in the precipitates. Electron micrographs displayed unbranched protofilament with a diameter of approximately 70 A. The peak point of the difference spectrum for the Congo red binding assay was 541 nm, which is characteristic of amyloid fibrils. The X-ray diffraction pattern showed a sharp and intense diffraction ring at 4.7 A, a reflection that arises from the interstrand spacing in beta-sheets. These results indicate that the precipitates of hen egg lysozyme are amyloid protofilament, and that the amyloid protofilament formation of hen egg lysozyme closely follows upon the destruction of the helical and tertiary structures.

Amyloid↗

PubMed2000

Expression of a tetraheme protein, Desulfovibrio vulgaris Miyazaki F cytochrome c(3), in Shewanella oneidensis MR-1.

Cytochrome c(3) from Desulfovibrio vulgaris Miyazaki F was successfully expressed in the facultative aerobe Shewanella oneidensis MR-1 under anaerobic, microaerophilic, and aerobic conditions, with yields of 0.3 to 0.5 mg of cytochrome/g of cells. A derivative of the broad-host-range plasmid pRK415 containing the cytochrome c(3) gene from D. vulgaris Miyazaki F was used for transformation of S. oneidensis MR-1, resulting in the production of protein product that was indistinguishable from that produced by D. vulgaris Miyazaki F, except for the presence of one extra alanine residue at the N terminus.

Aerobiosis↗

PubMed2000

Evidence for the presence of an F-type ATP synthase involved in sulfate respiration in Desulfovibrio vulgaris.

Using a library of genomic DNA from Desulfovibrio vulgaris Miyazaki F, a strict anaerobe, and two synthetic deoxyoligonucleotide probes designed for F-type ATPases, the genes for open reading frames (ORFs) 1 to 5 were cloned and sequenced. The predicted protein sequences of the gene products indicate that they are composed of 172, 488, 294, 471, and 134 amino acids, respectively, and that they share considerable identity at the amino acid level with delta, alpha, gamma, beta, and epsilon subunits found in other F-type ATPases, respectively. Furthermore, a component carrying ATPase activity was partially purified from the cytoplasmic membrane fraction of the D. vulgaris Miyazaki F cells. The N-terminal amino acid sequences of three major polypeptides separated by sodium dodecyl sulfate-12% polyacrylamide gel electrophoresis were identical to those of the products predicted by the sequences of ORF-2, ORF-3, and ORF-4, suggesting that an F-type ATPase is functioning in the D. vulgaris Miyazaki F cytoplasmic membrane. The amount of the F-type ATPase produced in the D. vulgaris Miyazaki F cells is similar to that in the Escherichia coli cells cultured aerobically. It indicates that the enzyme works as an ATP synthase in the D. vulgaris Miyazaki F cells in connection with sulfate respiration.

Amino Acid Sequence↗

PubMed2000

Antiphospholipid syndrome with acute myocardial infarction and portal vein occlusion: a case report.

A 62-year-old woman was admitted to hospital because of chest oppression and abdominal discomfort. Coronary arteriography revealed that the proximal left anterior descending artery had a large thrombus with TIMI (Thrombolysis in Myocardial Infarction) Grade 3 flow. On the second hospital day, she had sudden hematemesis because of esophageal varices. Her general condition became stable with conventional therapy. On the 20th hospital day, coronary arteriography and arterial portography showed that the thrombus had diminished. Arterial portography also revealed total occlusion of the portal vein as well as giant gastric varices. She was diagnosed as antiphospholipid syndrome, based on the presence of lupus anticoagulant. The treatment of this case was very complicated because of the bleeding from the esophageal varices induced by the anticoagulant therapy for the thrombus. Prednisolone was administered for 1 month, but no remarkable effects were observed. Therefore, she was treated with endoscopic sclerotherapy for the esophageal varices and anticoagulant therapy for prevention of thrombosis.

Acute Disease↗

PubMed2000

Intramedullary clear cell ependymoma in the cervical spinal cord: case report.

OBJECTIVE AND IMPORTANCE: Clear cell ependymoma of the spinal cord has not been reported in the literature, although ependymoma in the cerebral and cerebellar hemispheres has been described. We present the first case report of this rare histological type of ependymoma arising in the cervical spinal cord and emphasize the importance of recognizing this histological entity. CLINICAL PRESENTATION: A 42-year-old woman presented with numbness in both upper limbs and spastic gait. Magnetic resonance imaging revealed an intramedullary tumor at the C6-T1 level with syringomyelia. INTERVENTION: The tumor was totally removed. Histological analysis revealed that the tumor was composed of round cells with perinuclear halos similar to those observed in oligodendroglioma. However, we diagnosed clear cell ependymoma because these tumor cells exhibited epithelial features and ependymal rosettes under light microscopic examination. CONCLUSION: Histological diagnosis was crucial to our determining whether to perform postoperative adjuvant therapy in this patient. Neurosurgeons should be aware of the possibility of this histological entity among intramedullary spinal cord tumors.

Adult↗

PubMed1999

A novel phosphoglycolipid archaetidyl(glucosyl)inositol with two sesterterpanyl chains from the aerobic hyperthermophilic archaeon Aeropyrum pernix K1.

The structures of two novel polar lipids (AGI and AI) of an aerobic hyperthermophilic archaeon, Aeropyrum pernix, were elucidated. AGI and AI were the only two major lipids and accounted for 91 mol% and 9 mol%, respectively, of total polar lipids of this organism. The core lipid of A. pernix total lipids consisted solely of 2,3-di-O-sesterterpanyl-sn-glycerol (C25,25-archaeol). The molecular weights of the free acid forms of AGI and AI were shown by FAB-mass spectrometry to be 1196 and 1034, respectively. AI was completely hydrolyzed by phosphatidylinositol-specific phospholipase C, while AGI was not hydrolyzed at all under the same condition for the hydrolysis of AI. The molar ratio of phosphate, myo-inositol, and glucose in AGI was 1.0:0.97:0.95. The positions of linkages between myo-inositol and glucose, and between myo-inositol and phosphate in AGI were determined by NMR analyses of intact AGI and glucosylinositol prepared from AGI. Finally, it was concluded that the structures of AGI and AI were 2,3-di-O-sesterterpanyl-sn-glycerol-1-phospho-1'-(2'-O-alpha-D-glu cosyl)- myo-inositol (C25,25-archaetidyl(glucosyl)inositol) and 2,3-di-O-sesterterpanyl-sn-glycerol-1-phospho-myo-inositol (C25,25-archaetidylinositol), respectively. This is the first example that a core lipid of whole polar lipids is composed of only one species C25,25-archaeol in one organism and that glucosylinositol is found in a polar lipid as a polar head group.

Crenarchaeota↗

PubMed1999

Epidural block during general anesthesia attenuates urinary trypsin inhibitor excretion in lower abdominal surgery.

PURPOSE: The aim of this study was to elucidate whether urinary trypsin inhibitor excretion differs between general anesthesia (GA) and epidural block during general anesthesia (EPI) in lower abdominal surgery. METHODS: Sixteen women undergoing abdominal total hysterectomy were assigned to the GA and EPI groups. The GA group received propofol induction and maintenance with isoflurane, nitrous oxide, and vecuronium. The EPI group received epidural block, followed by propofol induction and maintenance with isoflurane and nitrous oxide. The levels of adrenocorticotropic hormone and cortisol during anesthesia and on postoperative days 1, 2, and 3, and the levels of urinary trypsin inhibitor in 12-h urine from the day of surgery to postoperative day 3, were measured. RESULTS: As compared with the EPI group, the GA group had a higher level of adrenocorticotropic hormone at the completion of anesthesia, higher levels of cortisol at the completion of anesthesia and postoperative day 2, and higher excretion of urinary trypsin inhibitor on the day of surgery and postoperative days 1 and 2. CONCLUSION: The present results suggest that excretion of urinary trypsin inhibitor into the urine under epidural block during general anesthesia is lower than that under general anesthesia alone in lower abdominal surgery. This is probably due to the difference in endocrine response to surgery between the two types of anesthesia.

Journal Article↗

PubMed1999

Functional conformation changes in the TF(1)-ATPase beta subunit probed by 12 tyrosine residues.

The effect of nucleotide binding on the structure of the F(1)-ATPase beta subunit from thermophilic bacillus PS-3 (TF(1)beta) was investigated by monitoring the NMR signals of the 12 tyrosine residues. The 3,5-proton resonances of 12 tyrosine residues could be observed for the specifically deuterated beta subunit. The assignment of 3,5-proton resonances of all of the tyrosine residues was accomplished using 14 mutant proteins, in each of which one or two tyrosine residues were replaced by phenylalanine. Binding of Mg. ATP induced an upfield shift of Tyr(341) resonance, suggesting that their aromatic rings are stacked to each other. Besides Tyr(341), the signal shift observed on Mg.ATP binding was restricted to the resonances of Tyr(148), Tyr(199), Tyr(238), and Tyr(307), suggesting that Mg.ATP induces a conformational change in the hinge region. This can be correlated to the change from the open to closed conformations as implicated in the crystal structure. Mg.ADP induced a similar but distinctly different conformational change. Therefore, the intrinsic conformational change in the beta subunit induced by the nucleotide binding is proposed to be one of the essential driving forces for the F(1) rotation. Reconstitution experiments showed that Tyr(277), one of the four conserved tyrosines, is essential to the formation of the alpha(3)beta(3)gamma complex.

Adenosine Diphosphate↗

PubMed1999

Alignment of separated patches: multiple location tags.

Gaussian and Gabor patches can be accurately localized; however, it is not yet clear which cues (or location tags) the visual system utilizes for localization. To determine the cues used in spatial alignment, we measured and modelled the perceived shifts for asymmetric Gaussian and Gabor patches over a wide range of separations, patch sizes and orientations. For Gaussian patches we observed perceived shifts that were generally consistent with that of the centroid of the envelope. For Gabor patches we found that the perceived shift depends on the carrier orientation (whether co-axial or orthoaxial with the patch arrangement), separation (in units of carrier wavelength) and patch size (number of cycles per standard deviation). Gabor patches with the carrier orthoaxial (horizontal) to the three vertically arranged patches, were similar to Gaussian patches. However, Gabor patches with the carrier coaxial (vertical) to the three vertically arranged patches resulted in perceived shifts that were consistent with a number of alternate localization primitives. The selection of primitives was dependent on mainly the separation and patch size. Our results support the suggestion that the visual system can use multiple tags for location (Hess et al., Vis Res 1994;34:2439-2451; Badcock et al., Vis Res 1996;36:1467-1472).

Cues↗

PubMed1999

Molecular mobility of protein in lyophilized formulations linked to the molecular mobility of polymer excipients, as determined by high resolution 13C solid-state NMR.

PURPOSE: The mobility of protein molecules in lyophilized protein formulations was compared with that of excipient molecules based on the spin-lattice relaxation time (T1) of each molecule determined by high resolution 13C solid-state NMR. The relationship between molecular mobility and protein stability is discussed. METHODS: Protein aggregation of lyophilized bovine serum gamma-globulin (BGG) formulation containing dextran was measured by size exclusion chromatography. The T1 of the BGG carbonyl carbon and dextran methin carbon in the formulation was determined by high resolution 13C NMR, and subsequently used to calculate the correlation time (tauc) of each carbon. The spin-spin relaxation time (T2) of BGG and dextran protons was measured by pulsed NMR spectrometry, and the critical temperature of appearance of Lorentzian relaxation due to liquid BGG and dextran protons (Tmc) was determined. RESULTS: The tauc of dextran methin carbon in BGG-dextran formulations exhibited a linear temperature dependence according to the Adam-Gibbs-Vogel equation at lower temperatures, and a nonlinear temperature dependence described by the Vogel-Tamman-Fulcher equation at higher temperatures. The temperature at which molecular motion of dextran changed was consistent with the Tmc. The tauc of BGG carbonyl carbon exhibited a similar temperature dependence to the tauc of the dextran methin carbon and substantially decreased at temperatures above Tmc in the presence of dextran. The temperature dependence of BGG aggregation could be described by the Williams-Landel-Ferry equation even at temperatures 20 degrees C lower than Tmc. CONCLUSIONS: High resolution 13C solid-state NMR indicated that the molecular motion of BGG was enhanced above Tmc in association with the increased global segmental motion of dextran molecules.

Algorithms↗

PubMed1999

Time dependency of the ratio of umbilical vein/maternal artery concentrations of vecuronium in caesarean section.

BACKGROUND: The ratio of umbilical vein (UV) and maternal artery (MA) concentrations of vecuronium may more accurately determine the placental transfer ratio during caesarean section. This ratio potentially correlates with the time from induction of anaesthesia to delivery (I-D time). The aim of this study was to determine the UV/MA ratio of vecuronium and its relationship with the I-D time. METHODS: Eighteen pregnant women at full term undergoing caesarean section were studied. The parturient was given intravenously 0.01 mg/kg vecuronium as a priming dose, followed 180 s later by 0.11 mg/kg vecuronium as an intubation dose and 4 mg/kg thiamylal. The time from the injection of the intubation dose to the clamping of the umbilical cord was regarded as the I-D time. At the time of clamping the umbilical cord, blood samples were collected and the UV and MA of vecuronium were measured. RESULTS: The UV/MA ratio and the I-D time, expressed as the mean (SD), were 0.056 (0.016) and 280 (57) s, respectively. The regression equation indicated y = 0.0083 + 0.00017 x (R2 = 0.381, r = 0.617, P = 0.0063, I-D time (s) = x, UV/MA = y). CONCLUSION: The present study demonstrated that the UV/MA ratio of vecuronium as an index of the placental transfer becomes smaller as the delivery time after injection of this drug becomes shorter during caesarean section.

Adult↗

PubMed1999

Prenatal diagnosis of intrapericardial teratoma: a case report.

A hydropic fetus that exhibited intrapericardial teratoma with marked pericardial effusion was prenatally diagnosed. Intrauterine pericardiocentesis was performed to diagnose and to treat hydrops. Pericardiocentesis for tamponade secondary to a fetal intrapericardial teratoma might prevent fetal death and premature delivery.

Adult↗