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Biomedical subjects

K Furuhata

Publications and source records attributed to K Furuhata.

At least 19 recordsLinked to original sources
PubMed1998

Induction of KDNase Sm, a deaminoneuraminic acid (KDN) residue-specific sialidase from Sphingobacterium multivorum, using synthetic KDN-glycosides.

Various aryl and alkyl alpha-glycosides of KDN were synthesized and tested as substrates for their susceptibility to a deaminoneuraminic acid (KDN)-specific sialidase from Sphingobacterium multivorum, designated KDNase Sm. The synthetic KDN-glycosides were all hydrolyzed by the action of KDNase Sm. A hydroxyl group at C-5 position of KDN was required for the recognition by the enzyme, and was shown not to be replaced by an amino- or an acylamino group for the enzymatic recognition. These synthetic KDN-glycosides were also examined for their inducing activity of KDNase in S. multivorum and were shown to induce the KDNase activity effectively when the bacterium was cultured minimum salt medium containing both 0.1% glucose and 0.1% various KDN-glycosides. No KDNase activity was induced by the KDN-glycosides without 0.1% glucose. This is the first case of using synthetic KDN-glycosides as inducers of KDNase Sm.

Carbohydrate Conformation↗
PubMed1998

Histamine-releasing properties of T-3762, a novel fluoroquinolone antimicrobial agent in intravenous use. I. Effects of doses and infusion rate on blood pressure, heart rate and plasma histamine concentration.

T-3762, a newly developed fluoroquinolone antimicrobial agent, ciprofloxacin (CPFX) and ofloxacin (OFLX) were administered intravenously to anesthetized dogs by intravenous infusion, and blood pressure, heart rate and plasma histamine concentrations were monitored. T-3762 decreased blood pressure by 12.0%, without alterations in heart rate and plasma histamine concentration, only when infused at 150 mg/min. CPFX and OFLX both produced a rapid decrease in blood pressure in a dose-related manner, with an accompanying decrease in heart rate, but to a lesser extent. After infusion at 150 mg/min, CPFX caused death in 2 animals within a few minutes, while OFLX produced maximum decreases in blood pressure and heart rate, by 69.0% and 26.4%, respectively. The infusion of these 2 agents resulted in dose-related increases in plasma histamine concentrations parallel to the decreases in blood pressure: the maximum, attained with CPFX at 50 mg/min and OFLX at 150 mg/min, were 379.2 and 167.8 ng/ml, respectively. For CPFX and OFLX, the relationship between the maximum levels of decreased blood pressure and increased histamine concentration in plasma was highly significant. The hypotension induced by CPFX was efficiently reduced by the pretreatment of animals with antihistamines. The results from this study suggest that hypotension induced in dogs following the intravenous infusion of fluoroquinolone antimicrobial agents may be dependent on their ability to cause histamine release from cells and tissues, and indicates that T-3762 is devoid of this ability in comparison to CPFX and OFLX.

Animals↗
PubMed1998

Histamine-releasing properties of T-3762, a novel fluoroquinolone antimicrobial agent in intravenous use. II. Dermovascular permeability-increasing effect and action on peritoneal mast cells.

To predict the actions of T-3762, a newly developed fluoroquinolone antimicrobial agent, as well as ciprofloxacin (CPFX) and ofloxacin (OFLX), on injection sites when dosed parenterally, their ability to increase cutaneous vascular permeability in dogs and to release histamine from rat peritoneal mast cells was examined. CPFX and OFLX increased cutaneous vascular permeability in concentrations ranging from 16 to 32 microg/ml, while T-3762 was inactive at 2000 microg/ml. The vascular permeability-increasing activities of these drugs were inhibited efficiently by pretreatment with a combined dose of diphenhydramine and cimetidine. CPFX induced histamine release from rat mast cells in a dose-dependent manner, whereas T-3762 was ineffective. Therefore, it is concluded that fluoroquinolone antimicrobial agents may have the ability to cause an increase in cutaneous vascular permeability by releasing histamine from mast cells at the injection site when administered parenterally, and that T-3762 has minimum activity among the agents tested in this study.

Animals↗
PubMed1998

Purification and characterization of sialidase from porcine liver.

Sialidase [E.C.3.2.1.18] has previously been purified from porcine liver by procedures including extraction, ammonium sulfate precipitation, concanavalin A-Sepharose adsorption, activation, CM-Sepharose ion exchange chromatography, and HPLC on a Shim pack Diol 300 column. Two sialidase preparations, sialidase I and II, were obtained by CM-Sepharose column chromatography and were eluted with pH 4.5 and 5.0 buffers, respectively. The two enzyme preparations showed the same optimum pH, pH stability, and specificities for natural substrates. The two final preparations contained beta-galactosidase activity and showed three protein components of 64, 30, and 21 kDa with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which are derived from the beta-galactosidase multimer. The anti-beta-galactosidase multimer antiserum was able to precipitate sialidase activity. It is likely that porcine liver sialidase exists as a multienzyme complex with beta-galactosidase and carboxypeptidase (protective protein).

Animals↗
PubMed1998

Pharmacological properties of T-3762, a novel fluoroquinolone antimicrobial agent in parenteral use. III. Chemical structures and dermovascular permeability-increasing activities.

Fluoroquinolone antibiotics and chemically related compounds including the pazufloxacin methanesulfonate named T-3762 were examined for their ability to increase cutaneous vascular permeability following intradermal injection in dogs. A positive skin reaction was produced by the injection of a compound with a substituent of the piperazinyl, 4-piperizyl, 3-aminopyrolizinyl or 3-aminocyclobutyl group at the 7-position (C-7) of the quinolone skeleton at a minimum concentration of 101.8 microg/ml or less. Substitution at position 1, 6 or 8 of the ring nucleus hardly affected the activity of the compounds with the C-7 substituted piperazinyl group. The compounds with 7-positioned substituents other than the piperazinyl group showed relatively weak activity, and in particular those with the 1-aminocyclopropyl group including T-3762 were barely positive in concentrations of more than 500 microg/ml. An analysis of the three-dimensional models of the compounds with the C-7 substituted, nitrogen-containing groups revealed that the range of the geometrically optimum distance between the nitrogen and the carbon atoms was from 2.98 to 4.98 A for highly active compounds and from 2.47 to 2.65 A for weakly active compounds. In conclusion, the C-7 substituted piperazine moiety of the molecules of already-known fluoroquinolone antibiotics may be responsible for the ability to increase cutaneous vascular permeability, whereas T-3762 is practically inactive because the free amino nitrogen of the 1-aminocyclopropyl group is conformationally present at a shorter distance from the carbon atom at position 7 of the ring nucleus.

Animals↗
PubMed1995

[An outbreak of Pontiac fever due to Legionella pneumophila serogroup 7. I. Clinical aspects].

In August 1994, an epidemic of acute febrile illness occurred at the Education Center Building of a company in Shibuya-ku, Tokyo. All 43 trainees attended in two groups and 2 staff members of the Center fell ill. The 45 patients came to one of our hospitals in two groups, and 35 patients were treated. The patients were 4 males and 31 females, and the average age was 29.0 years. The duration until falling ill was 36 to 90 hours after entering the Center. Symptoms were fever, lumbago arthralgia, headache, dyspnea, general fatigue, etc. Physical examination revealed slightly injected mucosa of the pharynx in a patient who complained of a sore throat. On laboratory examination, leukocytosis with a left shift of the nucleus and elevation of serum CRP levels were found. Erythromycin (600 mg, daily) and nonsteroidal antiinflammatory drugs (NSAIDs) were given by mouth to almost every patient. Two patients were hospitalized. The illness was self-limited, generally lasting from two to five days. Strains of legionellae isolated from the water of the cooling tower located at the top of the Center, were identified as L. pneumophila serogroup 7. Since seroconversion in a patient against the cooling tower strain from 1:16 to 1:256 was determined and the clinical courses agreed with the definition of Pontiac fever by Glick et al, we concluded that the epidemic was an outbreak of Pontiac fever due to L. pneumophila serogroup 7. Pontiac fever is considered to be one of the community-acquired diseases. Thus, we have to note that Pontiac fever may be misdiagnosed as we examine patients who complain of the symptoms noted above.

Adolescent↗
PubMed1995

[An outbreak of Pontiac fever due to Legionella pneumophila serogroup 7. II. Epidemiological aspects].

From August 20 to 22, 1994, an outbreak of acute febrile illness occurred in a Training Center building of a company in Shibuya-ku, Tokyo. All 43 trainees attended in two groups and 2 Center staffs were attacked. Illness was self- limiting, generally lasting three days. Though strains of legionellae, isolated from the water of the cooling tower located at the top of the building, were identified as Legionella pneumophila by microplate DNA-DNA hybridization, they failed to agglutinate with antisera against L. pneumophila serogroups 1 through 6. Two strains were sent to the Centers for Disease Control, Atlanta, Georgia, USA, and determined as serogroup 7 of the species. Since the clinical courses agreed with the definition of Pontiac fever by Glick et al. and seroconversion in a patient against the cooling tower strain (EY3698)from 1:16 to 1:256 was determined by indirect fluorescent antibody technique, the epidemic of acute febrile illness was concluded as an outbreak of Pontiac fever due to L. pneumophila serogroup 7. The cooling tower was a cylindrical open style, with volumetric flow rate of 130 liter/min, and was used for air- conditioning exclusively to the third floor of the building. The building equipped no air-inlet, and indoor-air of the training room exchanged at every break time through windows of 168 cm in height and 72 cm in width. The cooling tower was not operated for five days before the Group A trainees checked in the Center on 18 August followed by Group B trainees on 19 August. It was speculated that high atmospheric temperature and stagnation of cooling water during this period would lead L. pneumophila to overly multiply, which could be a source of infection by flowing in through opened windows to the training rooms.

Disease Outbreaks↗
PubMed1995

Phenotypic and genetic diversity of chlorine-resistant Methylobacterium strains isolated from various environments.

Strains of pink-pigmented facultative methylotrophs which were isolated previously from various environments and assigned tentatively to the genus Methylobacterium were characterized in comparison with authentic strains of previously known species of this genus. Most of the isolates derived from chlorinated water supplies exhibited resistance to chlorine, whereas 29 to 40% of the isolates from air, natural aquatic environments, and clinical materials were chlorine resistant. None of the tested authentic strains of Methylobacterium species obtained from culture collections exhibited chlorine resistance. Numerical analysis of phenotypic profiles showed that the test organisms tested were separated from each other except M. organophilum and M. rhodesianum. The chlorine-resistant isolates were randomly distributed among all clusters. The 16S ribosomal DNA (rDNA) sequence-based phylogenetic analyses showed that representatives of the isolates together with known Methylobacterium species formed a line of descent distinct from that of members of related genera in the alpha-2 subclass of the Proteobacteria and were divided into three subclusters within the Methylobacterium group. These results demonstrate that there is phenotypic and genetic diversity among chlorine-resistant Methylobacterium strains within the genus.

Bacterial Typing Techniques↗
PubMed1995

Louisianins A, B, C and D: non-steroidal growth inhibitors of testosterone-responsive SC 115 cells. II. Physico-chemical properties and structural elucidation.

New non-steroidal growth inhibitors of testosterone-responsive SC 115 cells, louisianins A (MW: 189; C11H11NO2), B (MW: 191; C11H13NO2), C (MW: 173; C11H11NO) and D (MW: 173; C11H11NO) were isolated from the cultured broth of Streptomyces sp. WK-4028. Their structures were determined on the basis of spectroscopic data. The structure of louisianin A in particular was confirmed by X-ray crystallographic analysis. The four compounds commonly possess a unique pyrindine skeleton in the molecule.

5-alpha Reductase Inhibitors↗
PubMed1995

[General pharmacology of T-3761, a new oral quinolone antibacterial agent (1). Effect on the central nervous system].

General pharmacological effects of T-3761, a new oral quinolone antibacterial agent, on the central nervous system were investigated in laboratory animals. The results obtained are summarized as follows. 1. T-3761 exerted no significant effects on spontaneous motor activity, motor coordination, pentobarbital-induced hypnosis, electroshock-, pentetrazole- or strychnine-induced convulsion, acetic acid-induced writhing responses, reserpine-induced hypothermia and ptosis in mice at oral doses of 100, 300 and 1,000 mg/kg. The same oral doses of T-3761 exerted no significant effects on body temperature and passive avoidance response in rats. 2. T-3761 had no effects on EEG in cats and spinal reflex in rats at intravenous doses of 10, 30 and 100 mg/kg. 3. Convulsions were not observed in mice after any oral combinations of T-3761 at a dose of 200 or 1,000 mg/kg with 14 different nonsteroidal anti-inflammatory drugs (NSAIDs) including fenbufen. 4. An oral combination of T-3761 even at a higher doses of 3,000 mg/kg with 4-biphenylacetic acid (BPAA) which is a principally active metabolite of fenbufen also did not induce convulsions in mice. 5. T-3761 did not inhibit GABA receptor binding in rat brain synaptic membranes at 10(-4) M in either the absence or presence of BPAA. These results suggest that T-3761 is an antibacterial agent which would be unlikely to produce any side effects on the central nervous system and to produce convulsion when combined with NSAIDs in clinical use.

Animals↗
PubMed1995

[General pharmacology of T-3761, a new oral quinolone antibacterial agent (2). Effect on the respiratory and cardiovascular systems, autonomic nervous system and other functions].

General pharmacological effects of T-3761, a new oral quinolone antibacterial agent, on the respiratory and cardiovascular systems, autonomic nervous system and other functions were investigated in laboratory animals. The results obtained are summarized as follows. 1. Respiratory and cardiovascular systems: Oral administration of T-3761 at doses of 100-1,000 mg/kg did not affect in conscious rats. But intravenous administration of T-3761 at doses of 10-100 mg/kg caused an increase in respiratory rate, induced hypotension, caused increase or decrease in heart rate and altered ECG patterns (elevation of T waves and reduction of voltage of QRS complexes, etc.) in anesthetized dogs. Intravenous administration of T-3761 at doses of 10-100 mg/kg showed respiratory rate increase or decrease, hypertension, heart rate decrease and ECG patterns changes (T waves elevation and extrasystole) in anesthetized rabbits. 2. Autonomic nervous system and smooth muscle organs: T-3761 increased the epinephrine-induced contraction of the isolated guinea pig vas deferens at concentration of 10(-5)-10(-4) g/ml. T-3761 decreased the acetylcholine-induced contraction of the isolated guinea pig ileum and epinephrine-induced relaxation of the isolated guinea pig trachea-chain at concentration of 10(-4) g/ml. T-3761 increased the norepinephrine-induced contraction of the isolated rabbit thoracic aorta at concentration of 10(-4) g/ml. Oral administration of T-3761 at a dose of 1,000 mg/kg exerted slight mydriasis in mice. 3. Digestive system: T-3761 decreased the spontaneous motilities of isolated ileum and colon at concentration of 10(-4) g/ml. Oral administration of T-3761 at a dose of 1,000 mg/kg inhibited gastric output and intestinal transit time in rats or mice. 4. Renal functions: Oral administration of T-3761 at a dose of 300 mg/kg increased Na+ excretion but did not affect PSP excretion in rats. 5. Hematological examinations: T-3761 showed no effects on resistance to hemolysis, blood coagulation and platelet aggregation in rabbits at concentration of 10(-6)-10(-4) g/ml. Oral administration of T-3761 at dose of 100-1,000 mg/kg did not affect bleeding time or blood glucose level in rats. 6. Miscellaneous effects: Intravenous administration of T-3761 at a dose of 100 mg/kg slightly inhibited the twitch tension of gastrocnemius in anesthetized rats. Oral administration of T-3761 at doses of 300-1,000 mg/kg exerted slight augmentation of carrageenin-induced hind paw edema in rats. From these results, it can be assumed that T-3761 had a wide safety margin as an oral antibacterial agent.

Animals↗
PubMed1994

[Contamination of hot water supply in office buildings by Legionella pneumophila and some countermeasures].

An assessment of the contamination by Legionella species of hot water supplied to office buildings was made based on 80 samples of water from 3 types of systems as follows: 20 samples supplied from instantaneous heaters, 20 samples from hot water storage type systems, and 40 samples from circulation type systems. Legionella spp. were detected in two samples (10.0%) from hot water storage systems and five samples (12.5%) of the circulation type. The number of Legionella spp. was 2.0 x 10-8.4 x 10(2) CFU/500 ml. All isolated strains were identified as Legionella pneumophila. All hot water samples with Legionella spp. showed a temperature range from 41-55 degrees C. Contamination may easily occur in hot water storage and circulation type systems, due to their presence for prolonged periods. Hot water may be therefor be a source of Legionnaires' disease. It is clear from the present study that Legionella spp. survived over long periods and proliferated considerably. Elimination of this organism requires careful cleaning of hot water storage tanks but this alone may not be sufficient. Heat treatment for 20 hours at 70 degrees C was found to be adequate for complete elimination. Experimentally, complete sterilization from Legionella spp. within 5 minutes was demonstrated by heating at 60 degrees C. As a countermeasure temperature of hot water should be maintained at more than 55 degrees C, as the best means for elimination while also giving consideration to the prevention of scalding.

Hot Temperature↗
PubMed1993

[Isolation of Methylobacterium spp. from drinking tank-water and resistance of isolates to chlorine].

On bacteriological examination of 100 samples of drinking tank water, standard plate count bacteria (36 degrees C, 24 h) and coliforms were not detected, conforming to the water quality criteria under the Water Supply Law. Ninety-five percent of test samples had concentrations of residual chlorine exceeding 0.1 mg/l. However, one characteristic heterotroph was isolated from 70% of these water samples. The bacteria showed glucose non-fermentative Gram-negative rods and formed pink colonies when cultured on standard agar medium at 30 degrees C for 7 days. It was oxidase-positive, catalase-positive and motile. Furthermore, utilization of methyl alcohol was a characteristic. From these characteristics, it was identified as genus Methylobacterium. The isolated Methylobacterium of 118 strains were divided into 60 types using 20 biochemical tests. Thirty Methylobacterium strains were examined for tolerance to chloride by contact with free residual chlorine of 0.1 mg/l concentration for 5 min. Considerable resistance to residual chlorine was evident. The TW-7 strain showed especially high tolerance, even surviving contact at 1.0 mg/l concentration of free residual chlorine for 10 minutes.

Chlorine↗
PubMed1992

Chlorination of cellulose with N-chlorosuccinimide-triphenylphosphine under homogeneous conditions in lithium chloride-N,N-dimethylacetamide.

Microcrystalline cellulose was chlorinated with N-chlorosuccinimide-triphenylphosphine under homogeneous conditions in LiCl-N,N-dimethylacetamide. At the early stage of the reaction only replacement of the 6-hydroxyl groups with chlorine was observed, and 3-hydroxyl groups were replaced at a lower rate with Walden inversion. The effects of reaction conditions on the extent of chlorination were studied in detail. More than two equivalents of chlorination reagents per glucose residue were necessary to attain a high degree of substitution (ds) by chlorine, and the maximum ds attained was 1.86. Chlorinated disaccharides were found in the hydrolyzates of chlorodeoxycelluloses hydrolyzed under mild conditions, and their structures were studied by mass spectrometry.

Acetamides↗
PubMed1991

Studies on glycosylation of the mitomycins. Syntheses of 7-N-(4-O-glycosylphenyl)-9a-methoxymitosanes.

Two new derivatives of glycosyl mitomycin C, 7-N-[4-O-(beta-D-glucopyranosyl and alpha-sialosyl)phenyl]-9a- methoxymitosanes, were synthesized, and their structures were elucidated by analysis of the nuclear magnetic resonance spectra. Field desorption mass spectrometry was successfully used for the confirmation of these structures. The cytotoxic, antibacterial, and antitumor activities of 7-N-(4-glycosylphenyl)-9a- methoxymitosanes were also examined.

Animals↗