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Biomedical subjects

Y Maeda

Publications and source records attributed to Y Maeda.

At least 847 records · Page 47Linked to original sources
PubMed1988

Differential scanning calorimetry of antitumor antibiotics-plasmid DNA interaction.

Differential scanning calorimetry (DSC) can detect stepwise melting of plasmid DNA along the molecular chain with high resolution. This method was applied to study interaction of some antitumor antibiotics with the plasmid pJL3-TB5 DNA (5277 base-pairs in length). Analysis of DSC curves of the plasmid DNA in the presence of, for example, adriamycin, an antitumor antibiotics of anthracycline group, together with theoretical analysis of the DNA melting curves obtained by calculation from the entire base sequence, led to the conclusion that adriamycin bound preferentially to the four particular regions with high G + C content. The DSC method would thus be useful for the study of properties of drugs which bind to DNA.

Antibiotics, Antineoplastic↗
PubMed1988

Compliance in epileptic children in Japan.

We investigated compliance in 133 epileptic patients with an onset before 15 years. Compliance was determined according to prescription rate. Those with a prescription rate over 95% were regarded as compliant and those with a rate below 95% as non-compliant. One-hundred patients (75.2%) were compliant. Good compliance was related to early onset of epilepsy, high seizure frequency, short duration of seizure-free period and self-reported complete intake of medicine. Duration of epilepsy, seizure/drug calendar recording, number of drugs and plasma level of antiepileptic drugs were not associated with compliance.

Adolescent↗
PubMed1987

High-performance liquid chromatographic determination of six p-hydroxybenzoic acid esters in cosmetics using Sep-Pak florisil cartridges for sample pre-treatment.

A rapid and simple method is described for the simultaneous determination of methyl, ethyl, isopropyl, n-propyl, isobutyl and n-butyl p-hydroxybenzoic acid esters (parabens) in cosmetics by high-performance liquid chromatography (HPLC). The method involves a single extraction of parabens with diethyl ether and clean-up on a Sep-Pak Florisil cartridge. Fat-soluble excipients in the diethyl ether extracts are removed through the cartridges with hexane-chloroform (75:25). Parabens are then eluted from the cartridges with hexane-ethyl acetate (70:30) and determined by HPLC on a reversed-phase column with water-methanol (50:50) as the mobile phase using sec.-butylpraben as an internal standard. The method was applied to samples with complicated matrices such as cream, milk lotion, lotion and cleansing foam, and the recoveries were 99.0-102.3% with coefficients of variation of 0.3-1.2%.

Chromatography, High Pressure Liquid↗
PubMed1987

Isolation and characterization of IS elements repeated in the bacterial chromosome.

Shigella sonnei contains repetitive sequences, including an insertion element IS1, which can be isolated as double-stranded DNA fragments by DNA denaturation and renaturation and by treatment with S1 nuclease. In this paper, we describe a method of cloning the IS1 fragments prepared by the S1 nuclease digestion technique into phage M13mp8 RFI DNA. Several clones contained IS1, usually with a few additional bases. We isolated and characterized five other repetitive sequences using this method. One sequence, 1264 base-pairs in length, had terminal inverted repeats and contained two open reading frames. This sequence, called IS600, showed about 44% sequence homology with IS3 and was repeated more than 20 times in the Sh. sonnei chromosome. Another sequence (named IS629, 1310 base-pairs in length), which was repeated six times, was found also to be related to IS3 and thus IS600. Two other sequences (named IS630 and IS640, 1159 and 1092 base-pairs in length, respectively), which were repeated approximately ten times, had characteristic terminal inverted repeats and contained a large open reading frame coding for a protein. The inverted repeat sequences of IS630 were similar to the sequence at one end of IS200, a Salmonella-specific IS element. The fifth sequence, repeated ten times in Sh. sonnei, had about 98% sequence homology with a portion of IS2. The method described here can be applied to the isolation of IS or iso-IS elements present in any other bacterial chromosome.

Chromosomes, Bacterial↗
PubMed1987

Relationship between helix-coil transition and gene organization of ColE1 plasmid DNA. Differential scanning calorimetric and theoretical studies.

Differential scanning calorimetry (DSC) was carried out to analyze the transition of helix to coil state of DNA, using ColE1 DNA molecules digested with EcoRI. The DSC curves showed multimodal transition, consisting of nine to 11 peaks over a temperature range, depending on the ionic strength of the DNA solution. These DSC curves were essentially in good agreement with the optical melting curves of ColE1 DNA. The theoretical melting profiles of ColE1 DNA were predicted from calculations based on the helix-coil transition theory and the nucleotide sequence of the DNA. These profiles resembled the DSC curves and made it possible to assign the peaks seen in the DSC curves to the helix-coil transition of particular regions of the nucleotide sequence of ColE1. The helix-coil transition of each of the small genes gave rise to a single peak in the DSC curve, while the helix-coil transition of large genes contributed to two or more peaks in the DSC curve. This multimodal transition within a single coding region might correspond to the melting of individual segments encoding the different domains of the proteins. The helix-coil transition at the specific sites including ori, the origin of replication of ColE1, was also found to occur in a particular temperature range. DSC, a simple method, is thus useful for analyzing the multimodal helix-coil transition of DNA, and for providing information on the genetic organization of DNA.

Bacteriocin Plasmids↗
PubMed1987

The effect of the dw gene on the muscle protein turnover rate in chickens.

Fractional rates (%/day) of muscle protein synthesis and degradation of the genotypes Dw/Dw and dw/dw of male White Plymouth Rock chickens were determined by measuring the output of N tau-methylhistidine (N tau-MH) in the excreta at 2, 4, and 8 weeks of age. The fractional growth rate of dw/dw was significantly lower (P less than 0.05) than that of Dw/Dw at 2 weeks of age but not at 4 and 8 weeks of age. No significant differences in the degradation rate (Kd; %/day) were found at any age. A significant difference (P less than 0.05) between genotypes in the rate of synthesis (Ks; %/day) was found at 2 weeks of age (Dw/Dw = 11.8, dw/dw = 9.9) but not at 4 and 8 weeks of age. These results suggest that the dw gene has a depressing effect on the synthesis rate of muscle protein, and the difference between genotypes in the growth rate at the early stage is a reflection of this effect.

Animals↗