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Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 91 records · Page 5Linked to original sources
PubMed2001

Isolation of Bacillus thuringiensis from intertidal brackish sediments in mangroves.

Intertidal brackish sediments in mangroves were examined for isolation of Bacillus thuringiensis strains with novel toxicity spectra. A total of 18 B. thuringiensis isolates were recovered from eight sediment samples (36.4%) out of 22 samples tested. The frequency of B. thuringiensis was 1.3% among the colonies of Bacillus cereus/B. thuringiensis group. While five isolates were allocated to the four H serogroups, the majority of the isolates were serologically untypable or untestable. Two isolates belonging to the serovar israelensis/tochigiensis (H14/19) exhibited strong toxicities against larvae of the mosquito, Culex pipiens molestus, and mammalian cells (sheep erythrocyte and two human cancer cell lines) in vitro. The other 16 isolates showed no toxicity against the mosquito and mammalian cells. None of the isolates showed larvicidal activity against the diamondback moth, Plutella xylostella. Strong lectin activities against sheep erythrocytes were associated with two serologically untestable isolates and an H3 isolate.

Animals↗
PubMed2001

The ste3 pheromone receptor gene of Pneumocystis carinii is surrounded by a cluster of signal transduction genes.

Although the clinical aspects of Pneumocystis carinii pneumonia are well characterized, the basic biology of the causative organism is poorly understood. Most proposed life cycles of P. carinii include both asexual and sexual replicative cycles. The two most prominent morphological forms are a trophic form, thought to undergo asexual replication by binary fission, and a cystic form or ascus containing intracystic bodies or ascospores, the products of sexual replication. To facilitate the Pneumocystis genome project, a P. carinii f. sp. carinii genomic cosmid library and an additional lambda cDNA library were generated. A partial expressed sequence tag database, created as part of the genome project, revealed the transcription of meiosis-specific genes and other genes related to sexual reproduction. The ortholog of Ste3, an a-factor pheromone receptor, was cloned and genes surrounding the ste3 locus were examined. Clustered around the ste3 gene are genes encoding elements functional in the pheromone response signal transduction cascade of model fungal organisms. These include the Ste20 protein kinase, the Ste12 homoeodomain transcriptional regulator, a potential pheromone mating factor, and other DNA-binding proteins. The genomic organization of the ste3 locus bears significant similarity to that of the mating locus recently described in Cryptococcus neoformans. The P. carinii genome contains much of the genetic machinery necessary for pheromone responsiveness, and these data support the existence of a sexual replication cycle.

Amino Acid Sequence↗
PubMed2001

Indocyanine green elimination rate detects hepatocellular dysfunction early in septic shock and correlates with survival.

OBJECTIVE: To determine whether indocyanine green clearance is an early indicator of hepatocellular injury in septic shock and to assess its predictive value. DESIGN: Observational study with prospective data collection. SETTING: Traumatology and critical care unit in a city hospital, staffed by traumatology and intensive care clinicians. PATIENTS: Twelve patients in septic shock who survived at least 2 months (group S) and nine patients who died within 2 wks (group N). INTERVENTIONS: Routine resuscitation from septic shock (surgery, fluid loading, and administration of catecholamines and antibiotic drugs). MEASUREMENTS AND MAIN RESULTS: Pulmonary artery occlusion pressure, cardiac index, oxygen delivery index, oxygen consumption index, and the indocyanine green elimination rate constant (KICG; or the slope of the loge [indocyanine green concentration] vs. time curve) 3-9 mins after injection were measured within 12 hrs of the onset of hypotension, then at 24 hrs, and every 24 hrs thereafter. Alanine aminotransferase and total bilirubin were measured on day 0 and day 1. Volume of fluid administered and duration of shock were the same in survivors and nonsurvivors. The oxygen consumption index was higher in survivors at 12 hrs, but no intergroup difference in pulmonary artery occlusion pressure, cardiac index, or oxygen delivery index was significant at any time point. KICG in nonsurvivors was lower than in survivors both initially and after 24 hrs, and it was subnormal in all patients except one survivor (p <.05). The KICG increased between 24 and 120 hrs in 11 survivors but progressively decreased and remained below 0.05 in seven nonsurvivors. The remaining two nonsurvivors died within 24 hrs of the initial measurement of KICG, which was >0.05. Alanine aminotransferase and total bilirubin were less sensitive measures of hepatic dysfunction in the first 24 hrs than the KICG. CONCLUSIONS: The KICG can identify reversible liver injury in septic shock, suggesting good prognosis. Either failure to increase the KICG within 120 hrs or an extremely low KICG is a poor prognostic sign.

Adult↗
PubMed2001

Activated platelets enhance microparticle formation and platelet-leukocyte interaction in severe trauma and sepsis.

BACKGROUND: Activated platelets have been recently reported to produce platelet microparticles and to enhance platelet-leukocyte interaction. The precise role of platelets in systemic inflammatory response syndrome (SIRS) has not been clarified. The objective of this study was to evaluate microparticle formation and platelet-leukocyte interaction in severe trauma and sepsis. METHODS: Twenty-six patients with severe SIRS (SIRS criteria and serum C-reactive protein > 10 mg/dL) and 12 healthy volunteers were studied. The severe SIRS was caused by trauma in 12 patients and sepsis in 14. Microparticle formation, P-selectin expression on platelets, platelet-monocyte binding, and platelet-polymorphonuclear leukocyte (PMNL) binding were measured by flow cytometry in the presence or absence of ionomycin, N-formyl-methionyl-leucyl-phenylalanine, or anti-CD62p monoclonal antibody. Soluble P-selectin, thrombomodulin, neopterin, and PMNL elastase in blood were also measured. RESULTS: Microparticle formation, P-selectin expression on platelets, platelet-monocyte binding with or without ionomycin, and platelet-PMNL binding with ionomycin significantly increased in patients with severe SIRS in comparison with values in normal volunteers. The increased platelet-leukocyte binding in severe SIRS patients was markedly inhibited by P-selectin blockade and was not enhanced by N-formyl-methionyl-leucyl-phenylalanine. Soluble P-selectin, thrombomodulin, neopterin, and PMNL elastase in blood also increased in these patients. CONCLUSION: Activated platelets enhance microparticle formation and platelet-leukocyte interaction in severe trauma and sepsis. Enhanced platelet-leukocyte interaction is dependent on P-selectin expression and may be involved in the systemic inflammatory response after severe inflammatory insult.

Adolescent↗
PubMed2001

Partial bladder resection in a bitch with urinary retention following surgical excision of a vaginal leiomyoma.

Ovariohysterectomy and surgical excision of a vaginal leiomyoma were performed in a bitch exhibiting continuous bleeding from the vulva. Following excision of the tumour, urine retention and urinary incontinence developed. Treatment using drugs and an indwelling catheter was unsuccessful in correcting the disorders and chronic cystitis developed after long-standing urine stagnation in the bladder. The authors resorted to undertaking partial cystectomy in order to correct the condition, which resulted in reduced urine retention and improved micturition.

Animals↗
PubMed2001

Protective effect of Lactobacillus casei strain Shirota on Shiga toxin-producing Escherichia coli O157:H7 infection in infant rabbits.

We examined colonization patterns of Shiga toxin-producing Escherichia coli (STEC), concentrations of Shiga toxins (Stxs) and specific immunoglobulin A (lgA) against Stxs and STEC bacterial cell surface antigen in various portions of the gastrointestinal tract in an infant rabbit infection model. After inoculation of 3-day-old infant rabbits with STEC strain 89020087 at low doses (approximately 10(3) CFU/body), numbers of colonizing STEC bacteria and concentrations of Stxs in the intestine increased dramatically and the animals developed diarrhea within a couple of days after infection. Daily administration of Lactobacillus casei from the day of birth dramatically decreased the severity of diarrhea and lowered STEC colonization levels in the gastrointestinal tract 100-fold day 7 after infection. Both Stx1 and Stx2 concentrations in the intestines and histological damage to the intestinal mucus induced by STEC infection were decreased by the administration of L. casei. Examination of the concentrations of volatile fatty acids and pH of the intestinal contents revealed that the protective effect of L. casei administration against STEC infection was not due to fermented products such as lactic acid in the gastrointestinal tract. Administration of L. casei increased levels of lgAs against Stx1, Stx2, and formalin-killed STEC cells in the colon approximately two-, four-, and threefold, respectively, compared with those of the untreated controls by day 7 after infection. These results suggest that administration of L. casei strain Shirota enhances the local immune responses to STEC cells and Stxs and leads to elimination of STEC and thus decreases Stx concentrations in the intestines.

Animals↗
PubMed2001

Antifungal susceptibilities, varieties, and electrophoretic karyotypes of clinical isolates of Cryptococcus neoformans from Brazil, Chile, and Venezuela.

One hundred clinical isolates of Cryptococcus neoformans from human immunodeficiency virus (HIV)-infected and non-HIV-infected patients from Brazil, Chile, and Venezuela were separated according to varieties and tested for antifungal susceptibility. A high susceptibility to antifungal agents was observed among all the isolates. The electrophoretic karyotyping of 51 strains revealed good discrimination among Cryptococcus neoformans var. neoformans strains.

AIDS-Related Opportunistic Infections↗
PubMed2001

Unique monoclonal antibody recognizing the third extracellular loop of CXCR4 induces lymphocyte agglutination and enhances human immunodeficiency virus type 1-mediated syncytium formation and productive infection.

To increase insight into the structural basis of CXCR4 utilization in human immunodeficiency virus type 1 (HIV-1) infection, a new generation of three monoclonal antibodies (MAbs) was developed in WKA rats. The A80 MAb, which binds an epitope in the third extracellular loop (ECL3) of CXCR4, has unique biologic properties that provide novel insights into CXCR4 function. This agent enhanced syncytium formation in activated human peripheral blood mononuclear cells (PBMC) infected with X4 or R5 and CEM cells infected with X4 HIV-1 strains. Exposure to A80 increased the productive infection of activated CD4(+) T cells and CEM cells with R5 and X4 viruses, respectively. This antibody uniquely induced agglutination of PBMC and CEM cells but did not activate calcium mobilization. Agglutination induced by A80 was inhibited by stromal cell-derived factor 1, T22, and phorbol 12-myristate 13-acetate but was not significantly altered by pretreatment of cells with pertussis toxin, wortmannin, or MAbs to LFA-1, ICAM-1, ICAM-2, and ICAM-3. The binding of the A145 and A120 MAbs was mapped to the N-terminal extracellular domain and a conformational epitope involving ECL1 and ECL2, respectively. Both of these MAbs inhibited HIV-1 infection and lacked the novel properties of A80. These results suggest a new role for CXCR4 in homologous lymphocyte adhesion that is ligand independent and in HIV-1 infection.

Amino Acid Sequence↗
PubMed2001

Maturational changes in extracellular matrix and lung tissue mechanics.

The viscoelastic properties of the pulmonary parenchyma change rapidly postparturition. We compared changes in mechanical properties with changes in tissue composition of rat lung parenchymal strips in three groups of Sprague-Dawley rats: baby (B; 10-14 days), young (Y; approximately 3 wk), and adult (A; approximately 8 wk). Strips were suspended in an organ bath, and resistance (R), elastance (E), and hysteresivity (eta) were calculated during sinusoidal oscillations before and after the addition of acetylcholine (ACh) (10(-3) M). Strips were then fixed in formalin, and sections were stained with hematoxylin and eosin, Verhoff's elastic stain, or Van Gieson's picric acid-fuchsin stain for collagen. The volume proportion of collagen (%Col), the length density of elastic fibers (L(V)/Pr(alv)), and the arithmetic mean thickness of alveolar septae (T(a)) were calculated by morphometry. Tissue was also stained for alpha-smooth muscle actin (ASMA), and the volume proportion of ASMA (%ASMA) was calculated. Hyaluronic acid (HA) was quantitated by radioimmunoassay in separate strips. R and E in B strips were significantly higher, whereas eta was significantly smaller than in Y or A strips. Changes in these parameters with ACh were greater in B strips. T(a), %ASMA, and HA were greatest in B strips, whereas %Col and L(V)/Pr(alv) were least. There were significant positive correlations between R and E vs. T(a) and between percent change in R and eta post-ACh vs. T(a) and vs. %ASMA, and significant negative correlations between R and E vs. %Col and vs. L(V)/Pr(alv) and percent increase in all three mechanical parameters post-ACh vs. %Col. These data suggest that the relatively high stiffness, R, and contractile responsiveness of parenchymal tissues observed in newborns are not directly attributable to the amount of collagen and elastic fibers in the tissue, but rather they are related to the thickened alveolar wall and the relatively greater percent of contractile cells.

Acetylcholine↗
PubMed2001

Hemostatic activation in spontaneous intracerebral hemorrhage.

BACKGROUND AND PURPOSE: There is no in-depth information available on the changes in hemostatic systems in patients in the acute phase of spontaneous intracerebral hemorrhage (ICH). This study was conducted to assess the relationships between the changes in hemostatic systems and clinical parameters in patients in acute-phase ICH. METHODS: The records of 358 patients admitted within 6 hours of onset of ICH were reviewed to examine the relationships between changes in hemostatic systems and computed tomographic findings and clinical parameters. RESULTS: -The white blood cell counts and the levels of thrombin-antithrombin complex, plasmin-antiplasmin complex, and D-dimer in patients with intraventricular extension (IVE) or subarachnoid hemorrhage (SAH) were significantly (P<0.05) higher than those in patients without IVE or SAH. Most of the hemostatic system parameters in patients without IVE or SAH showed no significant differences compared with normal subjects. Multiple linear regression analysis revealed that the levels of thrombin-antithrombin complex significantly increased with an increase in the amount of SAH (P<0.001) and IVE (P<0.001). The levels of thrombin-antithrombin complex were not significantly associated with the volume of intraparenchymal hematoma. The level of the complex, however, was significantly (P<0.001) and independently associated with the presence of IVE or SAH (multiple logistic regression analysis). CONCLUSIONS: The systemic activation of hemostatic systems in ICH patients seems to take place only when blood reaches the subarachnoid space. The intraparenchymal hematoma itself seems unlikely to activate hemostatic systems in peripheral blood, although the hematoma is expected to cause local activation of hemostatic systems.

Antifibrinolytic Agents↗
PubMed2001

Rat small intestine muscle relaxation alkaloids from Orixa japonica leaves.

Two quinoline alkaloids, japonine (1) and eduline (2) were isolated from the methanol extract of the leaves of Orixa japonica as relaxants against rat small intestine muscle. The activity of these alkaloids was comparable to that of the typical muscle relaxant papaverine (4). This is also the first report of the isolation of eduline (2) from O. japonica.

Alkaloids↗
PubMed2001

Studies on chemical modification of monensin IX. Synthesis of 26-substituted monensins and their Na+ ion transport activity.

The C-26 modified monensin derivatives, 26-O-benzoylmonensin (3), 26-O-benzylmonensin (4) and 26-phenylaminomonensin (5) were prepared from monensin (1). Na+ ion transport activity through biological membrane and antibacterial activity of 3-5 were evaluated and compared with the activities reported for a 26-phenylurethane derivative (2). Among these compounds, 5 showed the largest Na+ ion transport and antibacterial activities. In these compounds, the formation of head-to-tail hydrogen bonds was suggested to be an important factor for Na+ ion transport and antibacterial activities.

Anti-Infective Agents↗
PubMed2001

[New orally active penem antibiotic: Farom].

An orally active penem antibiotic, Farom (generic name: faropenem), was designed by the conformational analysis of active and inactive penem derivatives. Faropenem showed potent activity against a wide variety of bacteria including extended-spectrum beta-lactamase (ESBL)-producing ones. The mechanism of the stability against ESBL was elucidated by modeling the Michaelis complex of faropenem and Toho-1, an ESBL. Modeling of a complex of faropenem at the active site of a penicillin-binding protein 2 (PBP2) model suggested the characteristic affinity for faropenem with PBP2 of Escherichia coli. Faropenem has been totally synthesized from (R)-1,3-butanediol. The synthetic intermediate, a 3-hydroxyethyl-4-acetoxyazetidinone derivative, was efficiently prepared by the 2 + 2 coupling of a optically active vinylsulfide derivative and chlorosulfonyl isocyanate, followed by the substitution of the acetoxy group for the thiophenyl group at the C-4 position.

Anti-Bacterial Agents↗
PubMed2001

Molecular cloning of groESL locus, and purification and characterization of chaperonins, GroEL and GroES, from Bacillus brevis.

The groESL locus of a protein-hypersecreting bacterium, Bacillus brevis, was cloned by PCR using primers designed based on the DNA sequence of a B. subtilis homolog. GroEL protein was purified to apparent homogeneity and its ATPase activity was characterized: it hydrolyzed ATP, CTP, and TTP in this order of reaction rate, and its specific activity for ATP was 0.1 micromole/min/mg protein. Purified GroEL forms a tetradecamer. GroEL was estimated to contain 22% alpha-helix, 24% beta-sheet, and 19% turn structures, by CD measurement. GroES protein was also highly purified to examine its chaperonin activity. GroEL protected from thermal inactivation of and showed refolding-promoting activity for malate dehydrogenase, strictly depending on the presence of ATP and GroES.

Adenosine Triphosphatases↗
PubMed2001

Plasma digoxin concentration in dogs with mitral regurgitation.

Fifteen and eight mature beagles, without (normal group) and with experimental mitral regurgitation (MR group), respectively, were given 0.02 mg/kg/day digoxin powder for 10 days orally. The optimum time for sample collection after administration of digoxin was observed to be 8-18 hr and 10-22 hr in the normal and MR groups, respectively. In both groups, a stable concentration was reached after 3-5 days of treatment. No differences in plasma level were observed between sexes. The optimum concentration of digoxin was attained at an earlier stage than has been previously reported for both dogs and humans.

Animals↗
PubMed2001

Supplemental embolization coil implantation for closure of patent ductus arteriosus in a beagle dog.

Embolization coil for the occlusion of patent ductus arteriosus (PDA) was inserted in a beagle dog diagnosed as PDA with systolic murmur. Residual shunt was observed three months postoperatively and then supplemental coil was inserted. In the past only one coil was required for the closure of PDA in our cases with good post-operative results. In this case, however, the largest coil presently available (8 mm in diameter with 5 loops) was inadequate to make sufficient closure within 3 months postoperatively and supplemental coil insertion was necessary to produce a successful occlusion.

Animals↗
PubMed2001

Experimental study of materials for patch graft on right ventricular outflow tract under extracorporeal circulation in dogs--comparison between Denacol EX-313-treated bovine jugular vein graft and expanded polytetrafluoroethylene (EPTFE) graft.

A comparison between a bovine jugular vein treated with a hydrophilic polyepoxy compound cross-linker (Denacol), and expanded polytetrafluoroethylene (EPTFE), an artificial material, as a patch graft for the reconstruction of the right ventricular outflow tract under extracorporeal circulation in dogs, as if they had pulmonic stenosis, was made. Hemodynamic and histological examinations were conducted two weeks after the transplantation. Hemodynamic problems were not observed in either the Denacol or EPTFE groups. Macroscopically, organization of new tissue on the graft surface was more marked in the EPTFE group than in the Denacol group, and newly-formed tissue was seen surrounding the border of the graft and burying it in the EPTFE group. In the Denacol group, microscopic findings revealed the presence of inflammatory cells and fibroblasts, and an invasion of the graft by collagen fibers and elastic fibers. In the EPTFE group, there was minimal cellular infiltration of the graft and a thick layer consisting of collagen fibers and fibroblasts was observed around the graft. These results indicated that two weeks after transplantation the graft was better assimilated and organized with blood vasculature in the patch graft in the Denacol group than in the EPTFE group.

Animals↗