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Biomedical subjects

K Matsuura

Publications and source records attributed to K Matsuura.

At least 19 recordsLinked to original sources
PubMed2001

In vitro and in vivo electron transfer to the triheme cytochrome subunit bound to the photosynthetic reaction center complex in the purple bacterium Rhodovulum sulfidophilum.

The cytochrome subunit bound to the photosynthetic reaction center (RC) complex in Rhodovulum sulfidophilum lacks one heme-binding motif (CXXCH) out of four motifs found in other purple bacteria resulting in the absence of the most distal heme from the RC-core complex (S. Masuda et al., J. Biol. Chem. 274 (1999) 10795). Cytochrome c(2), which acts as the electron donor to the RC was purified, and its gene was cloned and sequenced. The redox midpoint potential of cytochrome c(2) was determined to be E(m)=357 mV. The photo-oxidation and re-reduction of purified cytochrome c(2) were observed in the presence of membrane preparations. Flash-induced photo-oxidation and re-reduction of the RC-bound cytochrome were also observed in intact cells. Despite the unusual nature of the RC-bound cytochrome subunit, the cyclic electron transfer system in Rdv. sulfidophilum was shown to be similar to those in other purple bacteria.

Amino Acid Sequence↗
PubMed2001

Different mechanisms of the binding of soluble electron donors to the photosynthetic reaction center of Rubrivivax gelatinosus and Blastochloris viridis.

The tetraheme cytochrome subunits of the photosynthetic reaction centers (RCs) in two species of purple bacteria, Rubrivivax gelatinosus and Blastochloris (Rhodopseudomonas) viridis, were compared in terms of their capabilities to bind different electron-donor proteins. The wild-type RCs from both species and mutated forms of R. gelatinosus RCs (with amino acid substitutions introduced to the binding domain for electron-donor proteins) were tested for their reactivity with soluble cytochromes and high potential iron-sulfur protein. Cytochromes from both species were good electron donors to the B. viridis RC and the R. gelatinosus RC. The reactivity in the R. gelatinosus RC showed a clear dependence on the polarity of the charges introduced to the binding domain, indicating the importance of the electrostatic interactions. In contrast, high potential iron-sulfur protein, presumed to operate according to the hydrophobic mechanism of binding, reacted significantly only with the R. gelatinosus RC. Evolutionary substitution of amino acids in a region of the binding domain on the cytochrome subunit surface probably caused the change in the principal mode of protein-protein interactions in the electron-transfer chains.

Bacterial Proteins↗
PubMed2001

Effect of Sotalol in the prevention of atrial fibrillation following coronary artery bypass grafting.

OBJECTIVE: We assessed the efficacy of postoperatively administered oral Sotalol in preventing the occurrence of postoperative atrial fibrillation. METHODS: Subjects were 80 consecutive patients undergoing coronary artery bypass grafting (CABG) randomized alternately into a Sotalol group (40 patients) administered 80 mg of oral Sotalol daily starting on the postoperative day 1 and continued for 14 days, and a control group (40 patients) matched for age and gender. RESULTS: The incidence of postoperative atrial fibrillation (21 patients) was significantly lower in the Sotalol group (6/40 patients; 15%) than in controls (15/40; 37.5%) (p < 0.05). Significant bradycardia or hypotension, necessitating drug withdrawal, occurred in 3 of 40 (7.5%) patients in the Sotalol group. None in the Sotalol group developed Torsardes de Pointes or sustained ventricular arrhythmias or other severe side effects. The sinus heart rate increased in both groups but less in the Sotalol group. QT, QRS, and QTc durations did not differ between groups. Postoperative hospital stay did not differ between groups. CONCLUSIONS: Oral Sotalol administration of 80 mg daily was associated with a significant decrease in postoperative atrial fibrillation in patients undergoing CABG without appreciable side effects. Sotalol should thus be considered in preventing postoperative atrial fibrillation in patients undergoing CABG in the absence of heart failure and significant left ventricular dysfunction.

Administration, Oral↗
PubMed2001

Horizontal transfer of the photosynthesis gene cluster and operon rearrangement in purple bacteria.

A 37-kb photosynthesis gene cluster was sequenced in a photosynthetic bacterium belonging to the beta subclass of purple bacteria (Proteobacteria), Rubrivivax gelatinosus. The cluster contained 12 bacteriochlorophyll biosynthesis genes (bch), 7 carotenoid biosynthesis genes (crt), structural genes for photosynthetic apparatuses (puf and puh), and some other related genes. The gene arrangement was markedly different from those of other purple photosynthetic bacteria, while two superoperonal structures, crtEF-bchCXYZ-puf and bchFNBHLM-lhaA-puhA, were conserved. Molecular phylogenetic analyses of these photosynthesis genes showed that the photosynthesis gene cluster of Rvi. gelatinosus was originated from those of the species belonging to the alpha subclass of purple bacteria. It was concluded that a horizontal transfer of the photosynthesis gene cluster from an ancestral species belonging to the alpha subclass to that of the beta subclass of purple bacteria had occurred and was followed by rearrangements of the operons in this cluster.

Amino Acid Sequence↗
PubMed2001

Expression of monocyte chemoattractant protein-1 in peritoneal endometriotic cells.

It is well known that the number of peritoneal macrophages is increased in patients with pelvic endometriosis. We measured the concentration of monocyte chemoattractant protein-1 (MCP-1) using an enzyme-linked immunosorbent assay (ELISA) in the peritoneal fluid of women with and without endometriosis. The expression of MCP-1 in pelvic endometriotic lesions obtained from the peritoneum was also examined using immunohistochemistry and nonradioactive in situ hybridization. The mean concentration of MCP-1 in the peritoneal fluid was significantly higher in the patients with endometriosis (P<0.05). The most significant elevation, compared with non-endometriosis patients, was found in stage I of the disease (P<0.05). However, no statistically significant difference was found among endometriosis stages I, II, III, and IV. Immunohistochemical staining revealed that MCP-1-positive cells were localized in the glandular epithelium of the endometriotic lesions and in the stromal macrophages distributed in those lesions, but normal peritoneal cells were negative. The in situ hybridization method demonstrated expression of MCP-1 mRNA on the endometriotic glandular epithelium and stromal macrophages. These findings suggest that MCP-1 may be involved in the histogenesis and early development of peritoneal endometriosis.

Ascitic Fluid↗
PubMed2001

Intracystic carcinoma of the male breast: report of a case.

We experienced a very rare case of male intracystic breast carcinoma. A 66-year-old man presented at our hospital because of a palpable mass in his right breast. The imaging diagnosis was an intracystic carcinoma with hemorrhagic fluid and two mural nodules. Modified radical mastectomy was performed under general anesthesia. The pathological examination revealed the intracystic papillary carcinoma with foci of microinvasion. The findings of power Doppler ultrasonography and dynamic magnetic resonance imaging were very useful for the differential diagnosis of our case.

Aged↗
PubMed2001

Barotraumatic blowout fracture of the orbit.

We report a rare case of a barotraumatic blowout fracture of the orbit. A 32-year-old woman presented with sudden swelling of the right orbital region after vigorous nose blowing. Computed tomography scan revealed a blowout fracture of the medial wall of the right orbit with orbital emphysema and herniation of the orbital soft tissue. She was treated with prednisolone and an antibiotic, and did not show diplopia or visual disturbance. Three different theories have so far been proposed to explain the mechanism of blowout fractures, globe-to-wall contact theory, hydraulic theory, and bone conduction theory. The present case indicates that blowout fractures of the orbit can be induced solely by a sudden change of pressure, thereby suggesting the validity of the hydraulic theory.

Adult↗
PubMed2001

Different effects between 7-nitroindazole and L-NAME on cerebral hemodynamics and hippocampal lesions during kainic acid-induced seizures in newborn rabbits.

We examined the effects of 7-nitroindazole (7-NI) and N-omega-nitro-L-arginine methyl ester (L-NAME) on the endogenous nitric oxide (NO) production in vivo, cerebral hemodynamics, and hippocampal lesions to investigate the different roles between endothelial NOS (eNOS) and neuronal NOS (nNOS) during kainic acid (KA)-induced seizures in newborn rabbits. After a pre-treatment with 7-NI (50 mg/kg, i.p.), L-NAME (20 mg/kg, i.v.) or saline (1 ml, i.v.), KA (12 mg/kg, i.v.) was administered. NO production in the brain, regional cerebral blood flow (rCBF), cerebral oxygenation (concentrations of oxyhemoglobin (HbO2), deoxyhemoglobin (HbR), and total hemoglobin (tHb) in the brain tissue), and electroencephalography (EEG) were continuously monitored throughout the experiment lasting at least 60 min after the KA administration. There was a significant increase in NO generation in the brain during KA-induced seizures, which was inhibited by a pre-treatment with 7-NI or L-NAME. KA-induced seizures also increased rCBF significantly, which was inhibited not by 7-NI but by L-NAME. L-NAME pre-treatment caused a significant decrease in HbO2 and a significant increase in HbR during KA-induced seizures, compared with 7-NI and saline pre-treatment. EEG abnormalities and Neuronal damages in the hippocampus were significantly lower in 7-NI- and L-NAME-treated animals respectively, than in saline-treated animals. The present data demonstrated that the selective nNOS inhibitor, 7-NI, attenuated neither rCBF nor cerebral oxygenation during the seizures, while the non-selective NOS (nNOS and eNOS) inhibitor, L-NAME, attenuated both. These findings suggest that NO, probably originating from eNOS, may play an important role in the cerebral circulation. Both 7-NI and L-NAME inhibited the NO production and EEG abnormalities during the seizures that led to less damage to the hippocampus.

Animals↗
PubMed2001

Management of posterior capsule rupture during phacoemulsification using the dry technique.

To manage posterior capsule rupture during phacoemulsification, we use a dry technique in which all procedures are performed without an irrigation/aspiration system. The dry technique is characterized by (1) continuous viscoelastic injection instead of fluid irrigation to maintain anterior chamber depth with the posterior capsule and vitreous located posteriorly and (2) static removal of most residual lens material by viscoexpression and/or manual small incision extracapsular cataract extraction without aspiration and dynamic water flow. In 16 cases of posterior capsule rupture managed using the dry technique, the residual nucleus and cortex were readily removed with minimum extension of the ruptured area and new vitreous loss. Although large amounts of viscoelastic material (mean 5.8 mL) were required, rapid and stable visual recovery was comparable to that in patients having uneventful surgery. The dry system is a safe and reliable technique for managing posterior capsule rupture during phacoemulsification.

Eye Injuries↗
PubMed2001

Phytoene desaturase, CrtI, of the purple photosynthetic bacterium, Rubrivivax gelatinosus, produces both neurosporene and lycopene.

Biosynthetic pathways for carotenoids in the purple photosynthetic bacterium, Rubrivivax gelatinosus, which synthesizes spirilloxanthin in addition to spheroidene and OH-spheroidene, were investigated by means of genetic manipulation. A phytoene desaturase gene (crtI) found in the photosynthesis gene cluster of this bacterium was expressed in an Escherichia coli strain that can produce phytoene. Both neurosporene and lycopene were synthesized in the recombinant, probably by three- and four-step desaturation reactions of CrtI. A mutant of RVI: gelatinosus lacking the crtI gene produced only phytoene, indicating that this organism had no other phytoene desaturases. When the crtI deletion mutant was complemented by the three-step phytoene desaturase of Rhodobacter capsulatus, spirilloxanthin and its precursors were not synthesized, although spheroidene and OH-spheroidene were accumulated. It was concluded that neurosporene and lycopene are produced by a single phytoene desaturase in RVI: gelatinosus resulting in the synthesis of spheroidene and spirilloxanthin, and that there are no pathways for spirilloxanthin synthesis via spheroidene.

Bacteria↗
PubMed2001

Absence of carotenes and presence of a tertiary methoxy group in a carotenoid from a thermophilic filamentous photosynthetic bacterium Roseiflexus castenholzii.

We identified pigments in a thermophilic filamentous photosynthetic bacterium Roseiflexus castenholzii strain HL08. We detected neither bacteriochlorophyll (BChl) c nor carotenes in this bacterium cultured under the aerobic dark and the anaerobic light conditions, which may correspond to its lack of chlorosomes. In the cells cultured under the aerobic dark conditions, the carotenoids were derivatives of keto-gamma-carotene, and the major ones were methoxy-keto-myxocoxanthin and keto-myxocoxanthin glucoside fatty acid ester. Although the tertiary methoxy group at C-1' and the double bond at C-3',4' in the psi end group of carotenoid, such as spirilloxanthin, have only been found in purple bacteria, this was the first such report in other bacterial groups. The fatty acid moiety was composed of iso fatty acids, which were rare in the cellular lipids. In the cells cultured under the anaerobic light conditions, in addition to these keto-carotenoids, we also found non-oxidized carotenoids (derivatives of gamma-carotene). Concerning the esterifying alcohol of BChl a, we found a substantial amount of geranylgeraniol, although the major component was phytol. The existence of these pigments makes this bacterium unique among the known species in CHLOROFLEXACEAE.

Aerobiosis↗
PubMed2001

Experimental study using pig eyes for realizing ideal astigmatic keratotomy.

PURPOSE: The effects of varying the incision length and depth were analyzed using pig eyes to acquire information for realizing an ideal method of astigmatic keratotomy (AK). METHODS: Single and paired arcuate incisions were made on pig corneas using a diamond knife. Incisions with varying lengths of 40 degrees, 60 degrees, and 90 degrees were made with the incision depth fixed at 90% of corneal thickness. Next, paired incisions with varying incision depth from 20% to 95% of corneal thickness were made with the incision length fixed at 90 degrees. The changes in corneal shape were analyzed using corneal topography and the degrees of astigmatic change were measured using a surgical keratometer. RESULTS: For short single and paired incisions (40 degrees or 60 degrees in length), narrow areas of flattenings occurred, and steepenings were observed on both sides adjacent to the flattened areas. For long paired incisions of 90 degrees length, wide areas of flattenings and steepenings were observed with an approximately 1:1 coupling ratio, and a positive linear relationship between the incision depth and degree of astigmatic change was observed in the range of incision depth between 40% and 80% of corneal thickness. CONCLUSION: This experimental study suggests that for achieving ideal corneal sphericity after AK, long incisions covering the entire steep areas (paired 90 degrees incisions for regular astigmatism) should be used and the degree of astigmatic correction may be controlled by varying the incision depth.

Animals↗
PubMed2001

Measures for preventing recurrence after pterygium surgery.

PURPOSE: To introduce an improved technique of pterygium surgery and to compare postoperative results between this technique and previous techniques. METHODS: In a retrospective survey, the records of 216 consecutive eyes with primary pterygium that underwent surgery by three different techniques were reviewed. The new technique (mini-flap technique) involves making a small excision of the pterygium body, removing the pterygium head by scraping with forceps, applying mitomycin C (MMC), and performing a small conjunctival transposition flap. The previous technique (large-flap technique II) involved making a large excision in the pterygium body, removing the pterygium head with a knife, applying MMC, and performing a large transposition flap. Large-flap technique I is the same as large-flap technique II except for the use of intraoperative MMC. The recurrence rate of each technique was estimated by the Kaplan-Meier life table analysis. RESULTS: The recurrence rates estimated at 1 year after surgery were 15.5% in large-flap technique I, 4.2% in large-flap technique II, and 0% in the mini-flap technique. Large-flap technique II or the mini-flap technique had significantly lower recurrence rates compared with large-flap technique I ( p = 0.02 and p < 0.01, respectively). The mini-flap technique had a significantly lower incidence of conjunctival scarring or granuloma compared with large-flap technique I and large-flap technique II ( p = 0.05 and p = 0.03, respectively.) CONCLUSIONS: The mini-flap technique was useful for preventing recurrence and was technically easier and induced fewer postoperative complications than large-flap techniques I and II.

Aged↗
PubMed2001

Clinical application of full-arc, depth-dependent, astigmatic keratotomy.

PURPOSE: To report a case series of the first clinical application of a new method of astigmatic keratotomy termed full-arc, depth-dependent astigmatic keratotomy (FDAK). METHODS: The type of astigmatism was analyzed by corneal topography. If the astigmatism was regular, paired arcuate incisions of 90 degrees length were used. Incision depth varied between 40% and 75% of local corneal thickness for controlling the level of astigmatic correction. RESULTS: All 13 cases had regular astigmatism, and paired arcuate incisions of 90 degrees length were used. Four cases with incisions at 40% depth, five cases at 50% depth, three cases at 60% depth, and one case at 75% depth induced vector astigmatic change of 0.93 +/- 0.33 D, 1.92 +/- 0.24 D, 3.17 +/- 0.26 D, and 4.44 D, respectively, 3 months after surgery. From 3 months to 1 year or 3 years, the postoperative astigmatism was stable, and no cases showed astigmatic regression of 0.50 D or more. Every topographic difference map indicated effective flattening and steepening occurring with a 1:1 coupling ratio. All postoperative color maps showed a marked improvement in corneal sphericity. CONCLUSIONS: In FDAK using paired 90 degrees incisions at 40-75% depth, an almost linear relationship between the incision depth and degree of astigmatic change was observed. FDAK may be an effective and safe method of astigmatic keratotomy that accurately controls the level of astigmatic correction. More clinical applications are necessary for drawing final conclusions and making a nomogram.

Aged↗