PubMed Health⌕ Search

Biomedical subjects

H Meguro

Publications and source records attributed to H Meguro.

At least 73 records · Page 4Linked to original sources

Functional characterization of a heteromeric NMDA receptor channel expressed from cloned cDNAs.

The glutamate receptor (GluR) channel plays a key part in brain function. Among GluR channel subtypes, the NMDA (N-methyl-D-aspartate) receptor channel which is highly permeable to Ca2+ is essential for the synaptic plasticity underlying memory, learning and development. Furthermore, abnormal activation of the NMDA receptor channel may trigger the neuronal cell death observed in various brain disorders. A complementary DNA encoding a subunit of the rodent NMDA receptor channel (NMDAR1 or zeta 1) has been cloned and its functional properties investigated. Here we report the identification and primary structure of a novel mouse NMDA receptor channel subunit, designated as epsilon 1, after cloning and sequencing the cDNA. The epsilon 1 subunit shows 11-18% amino-acid sequence identity with rodent GluR channel subunits that have been characterized so far and has structural features common to neurotransmitter-gated ion channels. Expression from cloned cDNAs of the epsilon 1 subunit together with the zeta 1 subunit in Xenopus oocytes yields functional GluR channels with high activity and characteristics of the NMDA receptor channel. Furthermore, the heteromeric NMDA receptor channel can be activated by glycine alone.

Amino Acid Sequence↗

High-performance liquid chromatography and post-column derivatization with diphenyl-1-pyrenylphosphine for fluorimetric determination of triacylglycerol hydroperoxides.

Triacylglycerol monohydroperoxides (TG-mHPO) were selectively detected at the picomole levels after post-column reaction with diphenyl-1-pyrenylphosphine (DPPP). TG-mHPO were separated on two types of reserved-phase columns, an ODS column and a phenylated silica gel column, which were useful for determining TG-mHPO at their molecular species levels and their class levels, respectively. After the separation, DPPP solution was mixed with the eluent followed by reaction in a stainless-steel coil 20 m x 0.5 mm I.D. at 80 degrees C, then the fluorescence intensity of DPPP oxide was measured (lambda ex. 352 nm, lambda em. 380 nm). Using these systems, TG-mHPO were determined in the range 2-1000 pmol. The relative standard deviations were 2.3-2.8%.

Chromatography, High Pressure Liquid↗

Cloning and functional expression of a cDNA encoding the mouse beta 2 subunit of the kainate-selective glutamate receptor channel.

The primary structure of the mouse glutamate receptor beta 2 subunit has been deduced by cloning and sequencing cDNA. The beta 2 subunit has structural characteristics common to the subunits of glutamate-gated ion channels. Expression of the cloned cDNA in Xenopus oocytes yields functional glutamate receptor channels selective for kainate.

Amino Acid Sequence↗

[Clinical evaluation of a new oral cephem, cefprozil in children].

Cefprozil (CFPZ, BMY-28100) was evaluated for its efficacy, safety and pharmacokinetics in children. CFPZ was effective against streptococcal pharyngitis, pneumococcal lower respiratory tract infections, staphylococcal skin infections and Escherichia coli urinary tract infections, but was less effective against lower respiratory tract infections and otitis media due to Haemophilus influenzae. No adverse reactions were encountered in 46 cases treated with CFPZ. With a premeal administration of 7.5 mg/kg, the Cmax was approximately 3.2 micrograms/ml and the T 1/2 beta was 1.4 hours. From the present study, CFPZ appears to be safe and effective against community-acquired childhood infections.

Administration, Oral↗

[Overall clinical evaluation of cefprozil against infections in pediatric fields. Pediatric Study Group for Cefprozil].

Cefprozil (CFPZ, BMY-28100) granule preparation was studied for pharmacokinetic, bacteriological and clinical aspects in the pediatric infections. The results obtained are summarized as follows: 1. Serum concentrations and urinary excretion. The pharmacokinetics of CFPZ in pediatrics was investigated by single oral administration of fine granules at doses of 4.0, 7.5 and 15.0 mg/kg. Peak blood levels of CFPZ were 3.06, 4.62 and 9.65 micrograms/ml, respectively, at 1.00-1.30 hours after each dose and AUCs were 7.44, 12.50 and 27.01 micrograms.hr/ml, respectively. These data showed that Cmax and AUC depended on dose levels. T 1/2 (beta) at these dose levels were 1.03, 0.94 and 1.01 hours, respectively. There were no differences related to dose. Urinary recovery rates in the first 6 hours after administration were 51.5-57.1%. The pharmacokinetics of CFPZ before or after meals were also investigated at a dose of 7.5 mg/kg. Peak blood levels were 4.88 micrograms/ml at 1.17 hours after administration in the fasting state, and 4.30 micrograms/ml at 1.54 hours after administration in the non-fasting state. Delay of Tmax and slight decrease of Cmax were observed in the non-fasting state, but T 1/2 and AUC were 0.91 hour and 12.96 micrograms.hr/ml, respectively, in the non-fasting state, and were similar to those in the fasting state, 0.93 hour and 12.82 micrograms.hr/ml, respectively. Urinary recovery rates in the first 6 hours after administration were 63.8% in the fasting state and 50.7% in the non-fasting state. 2. Clinical results. Clinical efficacies of CFPZ granules in various infectious diseases were studied in 804 cases. Twenty nine cases, mostly viral or mycoplasmal infections, were excluded from the statistical analysis. The clinical efficacy rate in 527 cases with causative bacteria isolated was 97.2%; and in 248 cases from whom no significant isolate had been obtained was 96.0%. The clinical efficacy rate in 475 cases with monobacterial infections (proven by culture of isolates) was 97.3%, and that in 52 case with polybacterial infections was 96.2%. Haemophilus influenzae was isolated mostly from acute respiratory infections. In 88 cases from whom H. influenzae was isolated, clinical efficacy rate was 95.5%. In cases from whom H. influenzae was found concomitant by with Staphylococcus aureus, Streptococcus pyogenes or Streptococcus pneumoniae, the clinical efficacy rates were also high. The bacteriological eradication rate in cases with 582 strains was 83.3%; the eradication rate for Gram-positive organisms was 95.8%; and for Gram-negative organisms, it was 64.2%.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

[MRSA infections in the neonatal unit].

MRSA infection in the neonatal unit is discussed, presenting our experience of an epidemic of TSST-1-positive strains in the Teikyo University Hospital in 1988-1989. Neonatal MRSA infections were experienced for the first time in 1982, and a few cases were treated each year from 1984 to 1987. In October 1988, MRSA-colonized and/or diseased cases increased abruptly after admission of several MRSA-positive neonates. The new strains were TSST-1-positive, coagulase type II organisms, which were multiply resistant, including gentamicin. The disease/colonization ratio was 37.0% in 108 colonized neonates. Among them, 5 cases of atypical TSS were experienced. The main clinical manifestation was an abrupt onset of shock with leukopenia. Some of the cases were afebrile and rash was hard to recognise. For the successful treatment of neonatal TSS, not only effective antibiotics but also prompt exchange transfusions were needed.

Cross Infection↗

[Clinical evaluation of panipenem/betamipron in children].

Panipenem/betamipron (PAPM/BP), a new injectable carbapenem antibiotic, was evaluated for its safety and efficacy in children. Ninety three percentage (14 in 15 cases) of various infections were cured with PAPM/BP therapy. Transient skin rash occurred in 1 case, probably due to the histamine-like effect of PAPM/BP. The plasma half life of panipenem was 0.85 +/- 0.07 hours. PAPM/BP was evaluated to be a less-epileptogenic carbapenem antibiotic.

Bacterial Infections↗

[Clinical evaluation of a new carbapenem, meropenem, in infants and children].

A new carbapenem antibiotic, meropenem (MEPM), was evaluated for its safety and efficacy in 33 infants and children. MEPM was effective in all the 32 evaluable cases including 4 cases of bacterial meningitis and 5 cases of Pseudomonas aeruginosa infections. The mean half life of plasma concentrations of MEPM was 0.84 +/- 0.09 hours after 30 minutes intravenous drip infusion. Mild diarrhea (2 cases), transient elevation of transaminases (8 cases), and transient eosinophilia (2 cases) were associated with the MEPM therapy, but none of them was problematic. These data suggest that MEPM is safe in infants and children and could be one of the therapeutic agents for severe infections or infections in compromised hosts.

Adolescent↗

[Overall clinical evaluation of panipenem/betamipron against infections in pediatric field].

To conduct a basic-clinical study on newly developed panipenem/betamipron (CS-533/CS-443, PAPM/BP) against various infections in pediatrics, a study group was organized and a joint research by 17 institutions and their related hospitals was undertaken. The obtained results are as follows. 1. Blood concentrations and urinary excretion Pharmacokinetics of PAPM/BP in children was studied using 30 minutes intravenous drip infusion of 10 mg/10 mg/kg, 20 mg/20 mg/kg and 30 mg/30 mg/kg, respectively. Maximum blood levels of PAPM/BP were observed at the completion of drip infusion and were 26.72 +/- 8.78 micrograms/ml/18.33 +/- 8.54 micrograms/ml (mean +/- S.D.) with administration of 10 mg/10 mg, 64.80 +/- 18.50 micrograms/ml/38.74 +/- 16.41 micrograms/ml with administration of 20 mg/20 mg and 91.70 +/- 29.42 micrograms/ml/50.08 +/- 22.41 micrograms/ml with administration of 30 mg/30 mg. Dose dependency was noted with these doses. The half-life was about 1 hour for PAPM and about 0.5 hour for BP. As for urinary excretion, PAPM was excreted about 30% and BP about 70% in the first 6 hours after the start of drip infusion. 2. Clinical results Twenty-five cases of exclusion and drop-out were deducted from a total of 391 cases and 8 cases having 2 diseases concurrently were added to the remaining 366 cases, hence 374 cases were evaluated in the study as the subjects of analysis of clinical effects. As for clinical effects in cases where pathogenic bacteria were detected, 215 out of 221 cases were rated as effective or above, hence the efficacy rate of 97.3% was obtained. In cases where pathogenic bacteria were not detected, 145 out of 153 cases were rated as effective or above, thus the efficacy rate was 94.8% which is similar to that in the cases where pathogenic bacteria were detected. The daily dose levels most commonly employed were 30 to 60 mg/kg (as PAPM) administered in 3 divided doses a day, and this regimen method accounted for 52.7% of the total cases, and the efficacy rate with this regimen was 97.0%. As for the bacteriological effect 87 (96.7%) out of 90 strains of Gram-positive bacteria (GPB) disappeared and 136 (91.3%) out of 149 strains of Gram-negative bacteria (GNB) disappeared upon the treatment. The overall bacterial eradication rate for the pathogenic bacteria was 93.4%.(ABSTRACT TRUNCATED AT 400 WORDS)

Bacteria↗

[Clinical evaluation of cefdinir 10% granules in children].

Cefdinir (CFDN, FK482) was evaluated in children with infections. CFDN was given at a daily dose of 6.4-19.8 mg/kg in 2 or 3 divided portions. CFDN was effective in 94% of 32 cases with respiratory tract, middle ear, urinary tract or skin structure infections. Side effects were loose stool and diarrhea (12.5%). In a pharmacokinetic study, 6.0 mg/kg of CFDN was given to each of the subjects before meal. Cmax was 0.81 +/- 0.38 microgram/ml, T 1/2 was 2.31 +/- 0.77 hours. Antibacterial activity against Staphylococcus aureus was the most excellent of oral cephem antibiotics tested. The data suggest that CFDN 10% granular preparation is safe and effective when used in children with infections caused by susceptible bacteria.

Administration, Oral↗

[Bacteriological, pharmacokinetic and clinical evaluations of cefpirome sulfate in the pediatric field. Pediatric Study Group of Cefpirome].

A research group was organized with the purpose of making basic and clinical studies on cefpirome sulfate (HR810, CPR), a newly developed cephalosporin antibiotic, in the pediatric field. Through meetings a joint research was done involving 19 key institutions and their related facilities throughout Japan. The obtained results are summarized as follows. 1. Antibacterial Activities Minimum inhibitory concentrations (MICs) were determined against 71 Gram-positive and 110 Gram-negative bacteria in the present clinical trials. CPR showed antibacterial activities 2-16 times higher than those of ceftazidime (CAZ) against Staphylococcus aureus and other Gram-positive bacteria including MRSA. Against Gram-negative bacteria, CPR showed a somewhat broad range of distribution in MIC against Branhamella catarrhalis, while the antibiotic inhibited the growth of all the strains of Escherichia coli and Haemophilus influenzae at concentrations no more than 0.10 and 0.20 micrograms/ml, respectively. 2. Blood Concentrations and Urinary Excretion Rates The pharmacokinetics in pediatric patients was investigated with a dose of 20 mg/kg in most cases via one shot intravenous injection or 30- and 60-minute intravenous drip infusion. Mean blood concentrations of CPR at 15 minutes after one shot intravenous injection of 10, 20, and 40 mg/kg were 51.2, 70.5, and 123.5 micrograms/ml, with half-lives of 1.21, 1.39, and 1.53 hours, respectively. Urinary excretion rates in 6 hours were 63.6, 66.0 and 71.6%, respectively for the 3 dose levels. After 30- and 60-minute intravenous drip infusions at the same dose, the pharmacokinetic parameters observed were similar to those obtained with one shot injections. 3. Concentration in the Cerebrospinal Fluid CPR penetrated well into the cerebrospinal fluid in patients with purulent meningitis and levels of 1.85-24.2 micrograms/ml 45-60 minutes were achieved after intravenous injection at a dose of 40-80 mg/kg, the penetration rate of CPR was at an intermediate degree compared with other cephalosporin antibiotics. 4. Clinical Results Clinical efficacies of CPR on infectious diseases were analyzed in 454 plus 3 cases which were complicated with other infectious diseases, hence totaling 457 cases out of 499 cases originally chosen for clinical evaluation. The remaining 45 cases were excluded from the clinical evaluation. As for the clinical efficacy, CPR was found to be effective (good or excellent) in 430 (94.1%) of the 457 cases. CPR was found to be effective in 243 (95.3%) of 255 cases for which causative bacteria were identified. The efficacy rate was 92.6% (187 of 202) in those cases in which causative bacteria were not identified.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

[Clinical evaluation of cefpirome in children].

A new injectable cephem antibiotic, cefpirome (CPR), was evaluated clinically in children. CPR was effective in all the 17 evaluable cases with acute bacterial infections including 1 case of purulent meningitis due to Haemophilus influenzae type b. Diarrhea and elevation of serum GOT and GPT were associated with CPR therapy in 2 young infants, although they were mild and transient. The plasma T 1/2 beta of CPR was 1.17 +/- 0.22 hours after bolus injection and mostly excreted in 6 to 8 hours into urine of children with normal renal functions. The data indicate that CPR is safe and effective, when used in children with susceptible bacterial infections.

Bacterial Infections↗

Functional expression from cloned cDNAs of glutamate receptor species responsive to kainate and quisqualate.

The complete amino acid sequences of two mouse glutamate receptor subunits (GluR1 and GluR2) have been deduced by cloning and sequencing the cDNAs. Xenopus oocytes injected with mRNA derived from the GluR1 cDNA exhibit current responses both to kainate and to quisqualate as well as to glutamate, whereas oocytes injected with mRNA derived from the GluR2 cDNA show little response. Injection of oocytes with both the mRNAs produces current responses larger than those induced by the GluR1-specific mRNA and the dose-response relations indicate a positively cooperative interaction between the two subunits. These results suggest that kainate and quisqualate can activate a common glutamate receptor subtype and that glutamate-gated ionic channels are hetero-oligomers of different subunits.

Amino Acid Sequence↗

A new approach to determine the stereospecificity in lipase catalysed hydrolysis using circular dichroism (CD): lipases produce optically active diglycerides from achiral triglycerides.

We describe a sensitive CD method for determining the stereospecificity in lipase (E.C.3.1.1.3) catalysed hydrolysis of triacyl glycerols into diacyl glycerols. The diglycerols were converted to chiral tert-butyldimethylsilylated 1,2- or 2,3-di-O-benzoyl-sn-glycerol (5 or 5'), and their CD was measured. This approach showed for the first time that lipases produce optically active diacyl glycerides from achiral tripalmitin and tribenzoyl glyceride with a variable extent of enantioselectivity depending on the acyl groups and the enzymes.

Benzyl Alcohols↗

[Therapeutic evaluation of combination therapy using C-425, human native immunoglobulin liquid preparation for i.v. administration, and antibiotics in severe and/or refractory infections in pediatrics].

A newly developed human immunoglobulin liquid preparation for intravenous injection was studied for efficacy, safety, and usefulness in treating severe and/or refractory infections in children receiving antibiotic treatment. It is suggested that C-425 is a useful intravenous preparation of human immunoglobulin for the treatment of severe and/or refractory infections in pediatrics. C-425 was administered to 87 inpatients with severe and/or refractory infections at 23 institutions nationwide. The Committee selected 61 cases for the present analysis. Physicians in charge judged clinical efficacy of C-425 to be "excellent" in 23 cases (40.4%), "good" in 24 (42.1%), "fair" in 7 (12.3%), "poor" in 3 (5.3%), and "unknown" in 4. The efficacy rate was calculated at 82.5% when the "excellent" and "good" cases were combined, and 94.7% when the "fair" cases were also included. According to the Committee's judgement, the efficacy of C-425 was "excellent" in 27 cases (44.3%), "good" in 18 (29.5%), "fair" in 7 (11.5%), and "poor" in 9 (14.8%). The efficacy rate was 73.8% when the "excellent" and "good" cases were combined. The rate increased to 85.2% when the "fair" cases were added. Organisms were identified in 31 cases, and the time course was followed in 19 instances. Organisms were eliminated in 12 cases (63.2%), decreased in number in 2 (10.5%), and persisted in 5 (26.3%). Eradication rate was 63.2%. One of the 87 patients died of fulminant hepatitis 2 days after the end of the treatment. The remaining 86 cases were analyzed for the safety of C-425. A skin rash was observed in one case. Laboratory examination revealed increase in transaminase levels in a total of 8 cases; both in GOT and GPT in 5, in GOT alone in 2, and in GPT alone in 1. These findings were not clinically important.

Anemia, Aplastic↗