Modification of the base and the sugar moieties of DNA with 4-(hydroxymethyl)benzenediazonium salt (HMBD), a carcinogen in the mushroom Agaricus bisporus, was investigated. When deoxyribonucleosides dGuo, dAdo, dThd, and dCyd were incubated with HMBD at pH 7.4 and 37 degrees C, the levels of all the nucleosides were decreased. The decrease was inhibited by ethanol or Cys. When deoxyribose was incubated with HMBD, malonaldehyde was released as assessed by the thiobarbituric acid reactivity. The release was inhibited by ethanol. Major products of the reaction of dGuo and dAdo with HMBD were isolated, and their structures were established to be 8-[4-(hydroxymethyl)phenyl]dGuo (8-HMP-dGuo) and 8-[4-(hydroxymethyl)phenyl]dAdo), respectively. Calf thymus DNA treated with HMBD was enzymatically digested into nucleosides, in which 8-HMP-dGuo and 8-HMP-dAdo were detected. Formation of the modified nucleosides in DNA was inhibited by ethanol or 2-mercaptoethanol. Malonaldehyde was released from DNA treated with HMBD, which indicated that the deoxyribose moiety of DNA had been damaged. The results indicate that the 4-(hydroxymethyl)phenyl radical generated from HMBD can directly modify the base and the sugar moieties of DNA under the mild conditions. Inhibitory effect of ethanol was ascribable to its scavenging activity for the carbon-centered radical. The inhibitory effect of Cys and 2-mercaptoethanol was found to be due to the formation of the reversible adducts between HMBD and the SH compounds.

Adenosine↗

PubMedDate not supplied

Microsatellite instability in gonadal tumors of XY pure gonadal dysgenesis patients.

To investigate genetic alternation accompanied by malignant transformation in gonadal tumors of XY pure gonadal dysgenesis patients, we investigated microsatellite instability in the hMSH1, hMSH2, TP53, and DCC loci, and ras mutations in two patients. The gonadal tumors from the patients were combined gonadoblastoma and dysgerminoma. Microsatellite instability and/or loss of heterozygotes (LOH) at hMSH1, hMSH2, and TP53 were detected in the dysgerminoma lesions of the both patients, but were not observed in any normal tissues. In the analyses of the H-, K-, or N-ras genes, where specific mutations have been frequently reported, no mutations were observed in the tumors. It is suggested therefore that microsatellite instability plays an important role in malignant transformation of gonadal tumors in patients with XY pure gonadal dysgenesis.

Adolescent↗

PubMedDate not supplied

Genetic analysis of serotype 23F Streptococcus pneumoniae isolates from several countries by penicillin-binding protein gene fingerprinting and pulsed-field gel electrophoresis.

We characterized 21 strains of serotype 23F Streptococcus pneumoniae isolated in various countries with various levels of penicillin susceptibility by penicillin-binding protein (PBP) gene fingerprinting and pulsed-field gel electrophoresis (PFGE). Pneumococci isolated in Israel, Hungary, Bulgaria, Slovakia, Rumania, France, the United States, Spain and Japan were included. These strains were classified into 12 and 18 groups by PBP gene fingerprinting and PFGE, respectively. Some of the pneumococci isolated in Spain, the United States and France appeared to be genetically related by PFGE, showed the same PBP gene pattern and had similar antimicrobial susceptibility patterns. One penicillin-susceptible Bulgarian strain, with a similar PFGE pattern but a different fingerprinting pattern, may be an ancestral recipient strain that became transformed into the resistant variants. Rumanian and Israeli strains were also genetically related by PFGE. These results indicate the existence of widely spread but related pneumococci in the world. PBP 2X gene profiles of pneumococci with MICs of 0.25 microg/ml were different from each other and from penicillin-susceptible pneumococci (PSP). PBP 2B gene profiles of these resistant strains were identical. PBP 2B gene profiles of pneumococci (penicillin MICs >/=0.5 microg/ml) were different from PSP. PBP gene profiles may not only be useful for genetic analysis but also for presumed penicillin susceptibility.

Bacterial Proteins↗

PubMedDate not supplied

Increased sensitivity to cisplatin in gastric cancer by antisense inhibition of the her-2/neu (c-erbB-2) gene.

BACKGROUND: The c-erbB-2 oncogene encodes a transmembrane tyrosine kinase receptor and its abnormal expression may be related to the prognosis of gastric cancer. Gastric cancer is relatively resistant to various drugs, including cisplatin. Cisplatin is widely used in cancer chemotherapy, but the mechanisms of drug resistance are not yet known. METHODS: We used the human gastric cancer cell lines MKN-7 and KATO-III, which express the c-erbB-2 oncogene, as a model for relative resistance to cisplatin. We investigated whether inhibition with antisense oligonucleotides against c-erbB-2 increased the sensitivity of MKN-7 and KATO-III cells to cisplatin. RESULTS: Antisense oligonucleotides for c-erbB-2 inhibited the expression of c-erbB-2 mRNA and protein and increased sensitivity to cisplatin, but not to other drugs, in MKN-7 and KATO-III cells. Cell growth was also inhibited by c-erbB-2 antisense oligonucleotides but not sense oligonucleotides. CONCLUSION: These findings indicate that c-erbB-2 expression in gastric cancer is one of the factors related to cisplatin sensitivity, and that anti-c-erbB-2 antisense oligonucleotides induced increased sensitivity to cisplatin.

Antineoplastic Agents↗

PubMedDate not supplied

Efficacy of roxithromycin in the treatment of mycoplasma pneumonia.

Macrolide and tetracycline antibiotics, which are protein synthesis inhibitors, are effective in the treatment of mycoplasma pneumonia. We evaluated the clinical efficacy and safety of roxithromycin, a new macrolide antibiotic, in the treatment of mycoplasma pneumonia. Roxithromycin was administered orally to patients who had been definitely diagnosed through Mycoplasma pneumoniae isolation or serum antibody titer as having mycoplasma pneumonia. The efficacy assessment was based on clinical signs and symptoms of infection as well as bacterial culture from clinical samples. Clinical efficacy was excellent in 6 cases, good in 6 cases and fair in 1 case, with an efficacy rate of 92.3%. The bacteriological effect was evaluated in 6 patients: the organism was eradicated in 4 cases and unchanged in 2 cases. In this study, the MIC of roxithromycin against M. pneumoniae fell in the range 0.0156-0.00625 mg/l. No adverse reaction was observed. As for abnormal laboratory findings, two cases showed elevated serum glutamic-pyruvic transaminase (S-GPT), one elevated serum glutamic-oxaloacetic transaminase and S-GPT, and one reduced neutrophil counts. From our results, we consider that roxithromycin is useful in the treatment of mycoplasma pneumonia.

Administration, Oral↗

PubMedDate not supplied

Trends of genetic relationship of serotype 23F penicillin-resistant Streptococcus pneumoniae in Japan.

No data on the genetic analysis of penicillin-resistant Streptococcus pneumoniae (PRP) in Japan has been reported. The SmaI restriction endonuclease digested patterns of chromosomal DNAs from 15 PRP serotyped 23F isolated in Japan were analyzed by pulsed-field gel electrophoresis (PFGE). The isolates were genetically heterogeneous and seven different PFGE patterns were identified. Nine strains were also resistant to erythromycin and tetracycline. Four strains revealed resistance to ceftriaxone. The PFGE patterns of some strains isolated in Nagasaki University Hospital were identical to each other and closely resembled those of isolates from three different areas of Japan. These results indicate a need for additional studies by PFGE to determine the possibility of clonal spread in Japan.

Anti-Bacterial Agents↗