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Biomedical subjects

S Miyoshi

Publications and source records attributed to S Miyoshi.

At least 19 recordsLinked to original sources
PubMed1992

Activation mechanism of human Hageman factor-plasma kallikrein-kinin system by Vibrio vulnificus metalloprotease.

Vivrio vulnificus, an opportunistic human pathogen, secretes a metalloprotease (VVP). The VVP inoculated into a guinea pig is known to generate bradykinin through activation of the Hageman factor-plasma kallikrein-kinin system. VVP was shown to possess the ability to activate the human system through the same mechanism as that clarified in the guinea pig system, namely, VVP converted both human zymogens (Hageman factor and plasma prekallikrein) to active enzymes (activated Hageman factor and plasma kallikrein), and the then generated kallikrein liberated bradykinin from high-molecular-weight kininogen. However, in the presence of plasma alpha 2-macroglobulin (alpha 2M), the VVP action was drastically decreased. This finding suggests that the human system might be activated only at the interstitial-tissue space which contains negligible amounts of alpha 2M or in the bloodstream of the individuals whose plasma alpha 2M level is extremely reduced.

Bacterial Proteins↗
PubMed1992

Occurrence of unusual heterogeneous lipid-containing granule-storing cells in the main excretory duct epithelium of the male mouse submandibular gland.

The fine structure of the main excretory duct epithelium of the male mouse submandibular glands was investigated by scanning and transmission electron microscopy. Three principal cell-types were observed: type I and II, and basal cells. This epithelium was characterized by the presence of intercellular canaliculi. Type-I cells were the most numerous. They had an abundance of mitochondria, well-developed Golgi apparatus, a few electron-lucent lipid-containing granules and poorly developed basal infoldings. These cells were also characterized by many glycogen granules throughout the cytoplasm and abundant smooth endoplasmic reticulum in the apical cytoplasm. Type-II cells were the second most numerous. Their most characteristic feature was the presence of abundant heterogeneous lipid-containing granules having acid phosphatase activity at the periphery. They were concentrated in the infra- and supra-nuclear cytoplasm. The granules may be derived from mitochondrial transformation and seem to be a special kind of secondary autolysosome. Type-II cells also contained abundant mitochondria throughout the cytoplasm, much smooth endoplasmic reticulum in the apical cytoplasm, a well developed Golgi apparatus adjacent to the heterogeneous lipid-containing granules and no basal infoldings. Basal cells were situated adjacent to the basal lamina. They had a large nucleus and the cytoplasm was filled with glycogen granules.

Acid Phosphatase↗
PubMed1992

Genetic differences in steroid-induced protein synthesis in vivo of the liver and magnum in immature chicks (Gallus domesticus).

1. The present study was conducted to investigate whether or not the rate of steroid-induced protein synthesis measured in vivo in the liver and magnum was different between chicks from different genetic backgrounds. 2. Both protein deposition and synthesis in the liver were enhanced after the administration of beta-estradiol with or without testosterone. In the magnum, the combined administration of beta-estradiol and testosterone resulted in significantly higher protein deposition and synthesis than did beta-estradiol alone. 3. After the administration of beta-estradiol and testosterone, protein deposition in the liver and magnum was lower in broiler than in layer and dual-purpose chicks. Protein synthesis in the magnum tended to be highest, though not significantly, in layer, followed by dual-purpose and broiler chicks in decreasing order. 4. Steroid-induced protein deposition in the liver was not changed between chicks genetically selected for low and high albumen contents. In contrast, steroid-induced protein synthesis in the magnum was significantly higher in high-albumen birds than low-albumen chicks. 5. It was concluded that genetic traits for high egg production were well reflected in increased protein deposition and synthesis in the liver and especially in the magnum of immature female chicks stimulated by steroid hormone treatment.

Animals↗
PubMed1992

Purification and characterization of a novel dipeptidyl carboxypeptidase from a Streptomyces species.

An extracellular protease derived from the culture broth of a microorganism, a Streptomyces species, produced Boc-Pro-Pro and diproline from Boc-Pro-Pro-Pro-Pro. The enzyme was purified 726-fold, with a yield of 2.6%, by ammonium sulfate fractionation, ion-exchange chromatography, and gel filtration chromatography. The molecular weight of the enzyme was determined to be 65,000 by gel filtration and 70,000 by SDS-PAGE. The enzyme released a C-terminal dipeptide from peptide substrates having a C-terminal proline and a penultimate proline or alanine residue, but did not hydrolyze angiotensin I or bradykinin. When the enzyme hydrolyzed Leu-Pro-Pro-Pro-Pro-Pro, it produced Leu-Pro-Pro-Pro and Pro-Pro before producing Leu-Pro. The enzyme thus seems to be a kind of dipeptidyl carboxypeptidase, its substrate specificity being very different from that of the well known dipeptidyl carboxypeptidases [EC 3.4.15.1] such as the angiotensin-converting enzyme.

Amino Acid Sequence↗
PubMed1992

Involvement of calcium in germination of coat-modified spores of Bacillus cereus T.

The effect of calcium on germination of coat-modified Bacillus cereus T spores was investigated. Coat-modified spores produced either by chemical extraction (SDS-DTT-treated spores) or by mutagenesis (10LD mutant spores) were unable to germinate in response to inosine. While SDS-DTT-treated spores could germinate slowly in the presence of L-alanine, 10LD mutant spores could not germinate at all. The lost or reduced germinability of coat-modified spores was restored when exogenous Ca2+ was supplemented to the germination media. The calcium requirement of coat-modified spores for germination was fairly specific. The simultaneous presence of germinant with Ca2+ was also required for germination of coat-modified spores. The optimal recovery of germinability was observed in the presence of 1.0 mM of calcium acetate. The calcium requirement itself was remarkably diminished under the condition in which L-alanine and a certain purine nucleoside analog, adenosine or inosine, coexisted. The lost or diminished germinability observed in SDS-DTT-treated spores or 10LD mutant spores may be attributed to the loss of calcium associated with the spore integuments.

Alanine↗
PubMed1992

Significant role of an exocellular protease in utilization of heme by Vibrio vulnificus.

Clinical and environmental isolates of Vibrio vulnificus could grow in a synthetic medium supplemented with heme protein as the iron source. Protease-deficient mutants of the bacterium could not utilize any of the heme proteins in the synthetic medium, but the addition of purified V. vulnificus protease restored their growth. The protease digested all heme proteins tested and elicited heme liberation from the proteins. Furthermore, the induction of protease production by the heme proteins was demonstrated. These observations suggest that protease contributes to the efficient utilization of heme by V. vulnificus.

Endopeptidases↗
PubMed1992

Oxygen transport during incremental exercise load as a predictor of operative risk in lung cancer patients.

To evaluate functional parameters related to the morbidity and mortality after thoracotomy, exercise loading was applied in 31 lung cancer patients under right heart catheterization. The routine pulmonary function and predicted postoperative pulmonary function (ppo) parameters were also evaluated. Patients were grouped according to postoperative complications: no complications (group 1, n = 17), nonfatal complications (group 2, n = 10), and fatal complications (group 3, n = 4). In all the patients %VCppo was above 40 percent and in patients undergoing pneumonectomy, pulmonary artery mean pressure during the unilateral pulmonary artery occlusion test was below 25 mm Hg. FEV1 percent and MVV/BSA were statistically significant between groups 1 and 2 but were not between groups 1 and 3 or groups 2 and 3. The %FEV1 ppo was statistically significant between groups 1 and 2 and groups 1 and 3 but was not between groups 2 and 3. Thus, the routine pulmonary function and predicted postoperative lung function tests, although they are mandatory for screening patients who are at risk, did not definitely discriminate between patients experiencing nonfatal and fatal complications after thoracotomy. VO2/BSALa20, CILa20, O2D/BSALa20, and TPVRILa20 were statistically significant between groups 1 and 3 and groups 2 and 3: in all the group 3 patients, as well as three patients of group 1 and one of group 2, VO2/BSALa20 was below 350 ml/min/m2. On the other hand, O2D/BSALa20 was below 500 ml/min/m2 in all the group 3 patients, while it was above 560 ml/min/m2 in all patients in groups 1 and 2. O2D/BSALa20 was the only parameter that definitely discriminated between experiencing nonfatal and fatal complications. We conclude that in addition to the generally accepted functional guidelines, VO2/BSALa20 should be above 400 ml/min/m2 and O2D/BSALa20 should be above 500 ml/min/m2 in patients who will undergo thoracotomy.

Adult↗
PubMed1992

Comparison of the University of Wisconsin preservation solution and other crystalloid perfusates in a 30-hour rabbit lung preservation model.

The University of Wisconsin solution, which contains a high potassium concentration (120 mmol/L), was evaluated for rabbit lung preservation by comparing it with a modified University of Wisconsin solution with low potassium (4 mmol/L), a low-potassium dextran solution (4 mmol/L), and simple surface cooling. In the first three groups rabbit lungs were flushed in situ with the solution (n = 5 in each group); then the lung-heart block was harvested and stored at 10 degrees C for 30 hours. In the surface cooling group the lungs were harvested without flushing and then simply immersed in saline and stored. For assessment, the stored lung was ventilated with room air and perfused with fresh venous blood at a rate of 40 ml/min for 10 minutes. Assessment of lung function included gas analysis of effluent blood, mean pulmonary artery perfusion pressure, and peak airway pressure. Among these parameters, oxygen tension was most sensitive. Oxygen tension at 10 minutes' perfusion in the modified University of Wisconsin (95 +/- 6 mm Hg) and low-potassium dextran (99 +/- 4 mm Hg) groups was significantly higher than that in the surface cooling (61 +/- 7 mm Hg) and University of Wisconsin (51 +/- 7 mm Hg) groups. There was no difference between the modified University of Wisconsin and low-potassium dextran groups or between the surface cooling and University of Wisconsin groups. We conclude that the low-potassium University of Wisconsin solution is superior to the high-potassium University of Wisconsin solution and that the lactobionate and raffinose included in the University of Wisconsin solution as impermeants do not improve lung preservation in this model.

Adenosine↗
PubMed1992

[A clinical investigation on renal pelvic and ureteral tumors].

Sixty-six patients with renal pelvic and ureteral tumors were treated in our hospital between June 1974 and June 1991. These cases consisted of 27 renal pelvic tumors, 31 ureteral tumors and 8 renal pelvic and ureteral tumors. Their ages ranged from 43 to 86 years old (average: 65). There were 46 males and 20 females. The surgical method involved total nephroureterectomy with a cuff for 44 patients, nephroureterectomy for 3, nephrectomy for 9, total nephroureterectomy with total cystectomy for 5 and partial ureterectomy for 2. Histologically, there were 60 transitional cell carcinomas (TCC), 2 squamous cell carcinomas (SCC) and 4 TCC with SCC. As for the pathological stage, 13 were pTa, 16 pT1, 12 pT2, 11 pT3, 13 pT4 and 1 pTX. Subsequent bladder tumors were found in 13 patients (19.7%). The overall survival rate at 1, 3 and 5 years were 80%, 68% and 52%, respectively according to the Kaplan-Meier's method. In this series, the pathological staging was the most important prognostic factor.

Adult↗
PubMed1992

Ecology and distribution of toxigenic Vibrio cholerae in aquatic environments of a temperate region.

The occurrence of a human pathogen, Vibrio cholerae, in aquatic environments and the distribution of toxigenic strains were studied for 2 years. The pathogen was isolated from freshwater, brackish and marine environments. V. cholerae non-01 was frequently recovered but the 01 serogroup was not detected. Of the 57 environmental strains tested, eight (12%) were found to be potentially toxigenic. A number of atypical V. cholerae 01 strains were found which showed higher virulence potentials than the serogroup non-01 strains. A significant correlation of the incidence of the pathogen was noted with water temperature in freshwater environments. In marine environments, a reciprocal correlation of the V. cholerae count and salinity was observed. The present study describes the ecology of V. cholerae in aquatic environments of a temperate region and notes that the occurrence of potentially virulent strains could be of public health significance.

Cholera Toxin↗
PubMed1992

[Clinical study on incidental renal cell carcinoma].

Of 93 patients with renal cell carcinoma treated at our hospital between January 1974 and December 1990, thirty-two cases with incidentally detected cancer were evaluated clinically and pathologically. The average age of the patients was 61 years old ranging from 39 to 84 years. There were 25 men and 7 women with a sex ratio of 3.6:1. Fourteen tumors had developed in the right kidney and 17 in the left kidney. One patient had bilateral tumors synchronously and was treated by radical nephrectomy with contralateral enucleation of the tumor. The proportion of incidental renal carcinoma has been increasing steadily; 87.5% of the cases was found by either abdominal ultrasonography or CT scan. Nineteen patients (59.4%) had a tumor smaller than 5 cm in diameter. There were 29 cases with G1 or G2 renal cancer and twenty with pT2. The five-year survival rate in the incidental cases was 52.2% with significantly better survival than in cases when metastasis was initially suspected, but there was no significant difference in survival between the incidentally found cases and the cases of symptomatic renal cancer.

Adult↗
PubMed1991

Cytoskeleton in microridges of the oral mucosal epithelium in the carp, Cyprinus carpio.

Microridges produce a characteristic fingerprint-like pattern on the surface of fish oral mucosa. The cytoskeleton in these microridges was examined by immunofluorescence microscopy and transmission electron microscopy after detergent extraction and decoration with myosin subfragment 1. The effect of cytochalasin B on microridges was probed with scanning electron microscopy. Immunofluorescence microscopy revealed that actin filaments were present throughout the periphery of the epithelial cells and were especially localized beneath the free surface of the epithelium. In thin sections treated with Triton X-100, the majority of filaments in the microridges and their bases were found to be actin filaments and a plexus of keratin filaments that underlay the network of actin filaments. A part of the plexus of keratin filaments entered the microridges. After extraction with Triton X-100 and decoration with myosin subfragment 1, decorated actin filaments were found in the microridge cores, connected to the keratin filaments. The keratin filaments aggregated in the pattern of microridges and a few of them protruded into the microridges. Treatment with cytochalasin B caused microridges to disappear or to become thinner and lower or to change short or microvillus-like microridges. When most microridges disappeared, the surface of the superficial cells was prominently swollen, but the cell boundaries were fastened, and the microridges in the periphery were preserved. On the basis of these observations, the possible roles of actin and keratin filaments in the maintenance and the formation of microridges are discussed.

Actins↗
PubMed1991

Filtration coefficient in isolated preserved and reperfused canine lung.

The filtration coefficient (Kf) in Starling's equation for fluid exchange was estimated in isolated reperfused canine lobes to evaluate the effect of ischemia-reperfusion injury on alveolar-capillary permeability quantitatively and to determine the inhibitory effects of a high dose of methylprednisolone (MPS) or dimethylthiourea (DMTU), a potent hydroxyl radical scavenger, on this injury. We reperfused isolated canine left lower lobes (LLLs) with blood at a constant flow after 3 hr of warm (38 degrees C) or cold (4 degrees C) ischemia and measured Kf after 1 hr of reperfusion. The mean value of Kf (+/- 1 SD) in the cold ischemic lobes (COLD, n = 7), 0.13 +/- 0.04 g.min-1.cmH2O-1.100 g-1, was not different from that in the control nonischemic lobes (CONT, n = 6), 0.10 +/- 0.04 g.min-1.cmH2O-1.100 g-1. In contrast, the mean value of the Kf in the warm ischemic lobes (WARM, n = 7), 0.38 +/- 0.17 g.min-1.cmH2O-1.100 g-1, was significantly (P less than 0.001) higher than in CONT.MPS (30 mg/Kg) or DMTU (0.75 g/kg) administered before isolation of LLL and before reperfusion reduced the increase in Kf in warm ischemic lobes to 0.19 +/- 0.09 and 0.19 +/- 0.05 g.min-1.cmH2O-1.100 g-1, respectively (P less than 0.005 WARM vs MPS, and P less than 0.01 WARM vs DMTU). MPS and DMTU also attenuated the impairment of gas exchange. We conclude that (1) reperfusion after 3 hr of warm ischemia increases Kf but after cold ischemia does not, and (2) MPS and DMTU prevent the increase in Kf.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Direct amygdaloid projections to the superior salivatory nucleus: a light and electron microscopic study in the cat.

Amygdaloid projections to the superior salivatory nucleus (SSN) were investigated in the cat by using the anterograde and retrograde tracing techniques of horseradish peroxidase (HRP). After HRP injections were made into the lingual nerve, retrogradely labeled SSN neurons were located in the lateral tegmental field medial to the spinal trigeminal nucleus from the middle level of the superior olivary nucleus to the caudal level of the facial nucleus. These labeled neurons, triangular, oval or polygonal in shape, were small to medium-sized (12-29 microns) and formed loosely packed clusters. In further HRP studies, HRP injections were made into the amygdala and in the reticular formation containing the SSN neurons. The results suggested that the SSN receives direct afferents from the central nucleus of the amygdala with ipsilateral predominance. Final proof of such direct connections from amygdala to the SSN can be obtained only by electron microscopic study. Therefore, HRP injections were made into the lingual nerve and in the amygdala in the same animal and electron microscopic observations were carried out on the SSN. It appeared that anterogradely labeled amygdalo-tegmental fibers formed axosomatic and axodendritic synaptic contacts with retrogradely labeled SSN neurons.

Afferent Pathways↗
PubMed1991

Alpha-macroglobulin-like plasma inactivator for Vibrio vulnificus metalloprotease.

The metalloprotease produced by Vibrio vulnificus (VVP) is known to be quickly inactivated by plasma proteins which belong to the class of alpha-macroglobulins in vitro at a molar ratio of 1:1. But the in vivo potential of the inactivators has not been studied. Macroalbumin (MA), a member of alpha-macroglobulins in guinea pig plasma, was found to inactivate VVP by means of physical entrapment in vitro. In vivo actions of VVP, permeability-enhancing and hemorrhagic actions, were greatly augmented by simultaneous injection of the antibody against MA, which had no effect on in vitro proteolytic action toward azocasein. The interstitial-tissue space in the normal guinea pig skin contains a negligible amount of MA. However, sufficient MA was present in the extravascular fluid collected after the intradermal injection of VVP. Besides, in the extravascular fluid, VVP formed a complex with MA and no inactivator other than MA was found. These results indicate that plasma MA leaked from the vascular system owing to the permeability-enhancing and hemorrhagic actions of VVP, resulting in inactivation of VVP in situ.

Animals↗
PubMed1991

Purification and characterization of a lecithin-dependent haemolysin from Escherichia coli transformed by a Vibrio parahaemolyticus gene.

Lecithin-dependent haemolysin (LDH) of Vibrio parahaemolyticus was purified from Escherichia coli C600 transformed with a plasmid (pHL591) ligated with a 1.5 kb DNA fragment of V. parahaemolyticus. The final preparation comprised two LDH proteins with different molecular masses which were immunologically cross-reactive and had the same enzymic activity. The LDH was a phospholipase hydrolysing both fatty acid esters of phospholipid, i.e. it hydrolysed phosphatidylcholine (PC) to lysophosphatidylcholine (LPC) and then LPC to glycerophosphorylcholine (GPC). From this point of view, LDH should be classified as a phospholipase B. Phospholipase B, however, does not usually show haemolytic activity, because the intermediate (LPC), which is the actual haemolytic agent, is immediately hydrolysed to the final product (GPC). On the other hand, LPC formed by LDH action was comparatively stable, because the rates of the two reactions catalysed by LDH, PC to LPC and LPC to GPC, are almost the same. This is the reason that LDH shows haemolytic activity. Therefore, LDH of V. parahaemolyticus is an atypical phospholipase to be designated as phospholipase A2/lysophospholipase.

Amino Acid Sequence↗
PubMed1991

Vascular permeability enhancement by Vibrio mimicus protease and the mechanisms of action.

Vibrio mimicus, a causative agent of gastroenteritis, has also been reported to attribute to extraintestinal infections. Recently we have purified a metalloprotease produced by the pathogen: however, the role of the protease in V. mimicus infection has not been documented. The V. mimicus protease (VMP) was found to enhance vascular permeability and form edema when injected into the dorsal skin of guinea pig and rat. The permeability enhancement by VMP was observed in a dose-dependent manner in both guinea pig and rat skin. In guinea pig, an inhibitor of the angiotensin-converting enzyme was found to augment the permeability enhancement reaction. The permeability enhancement was significantly blocked by soybean trypsin inhibitor (SBTI), an inhibitor of plasma kallikrein reaction. In vitro conversion of plasma prekallikrein to kallikrein by VMP was also noted. In rat skin, the permeability enhancement reaction was not blocked by antihistamine or SBTI. However, the reaction was partially blocked when a mixture of antihistamine and SBTI was administered with VMP. It is apparent from the study that in guinea pig skin, VMP enhances vascular permeability through activation of plasma kallikrein-kinin system which generates bradykinin, whereas in addition to the activation of plasma kallikrein-kinin cascade in the case of rat, stimulation of histamine release from mast cells and other unknown mechanism seem to be also a cause of the permeability enhancement reaction. These results suggest that VMP may play a role in extraintestinal infections with edema caused by the pathogen.

Angiotensin-Converting Enzyme Inhibitors↗