Polychlorinated biphenyl (PCB) tolerant derivatives of a strong PCB degrader, Rhodococcus strain RHA1, were selected after growth in the presence of 100 micrograms/ml PCBs. Some of the derivatives did not grow on biphenyl but accumulated a yellow coloured metabolite suggesting a defect in the meta-ring-cleavage compound hydrolase step encoded by the bphD gene. Other derivatives failed to grow on biphenyl and exhibited little PCB transformation activity suggesting a defect in the initial ring-hydroxylation dioxygenase step encoded by the bphA gene. These organisms had a structural alteration in the linear plasmids coding for the bph genes in RHA1, which included the bph gene deletion. When a bphD containing plasmid was introduced into a tolerant derivative, RCD1, which was shown to have bphD deletion, the defect in the growth on biphenyl of RCD1 was overcome. The bph gene deletion seems to play a key role in these tolerant derivatives thereby suggesting that the toxic metabolic intermediate would be a main cause of the growth inhibition of RHA1 in the presence of high concentration PCBs.

Benzene Derivatives↗

PubMedDate not supplied

Phakomatosis pigmentovascularis type IIIb associated with moyamoya disease.

We diagnosed phakomatosis pigmentovascularis type IIIb in an 11-month-old baby who had a giant nevus spilus, a nevus flammeus, and moyamoya disease. Development of the patient was normal until 6 months of age when he developed a sudden onset of focal seizures and left hemiparesis. This patient represents the sixth case of phakomatosis pigmentovascularis type IIIb, including three cases in the Japanese literature, reported thus far. However, to our knowledge, this is the first case with an association to moyamoya disease.

Humans↗

PubMedDate not supplied

Effects of biopsy on lung metastasis.

In order to clarify whether biopsy promotes lung metastasis, open or needle aspiration biopsy was performed 10 or 21 days after S-SLM osteosarcoma cells were transplanted subcutaneously in Fischer rats. The lungs were excised after six weeks and the lung weight and the number of metastatic nodules were measured. The mean weight was more in open than needle biopsy, and the number of nodules was significantly higher in open biopsy after 10 days, compared to the control. From these results we concluded that open is more likely to promote lung metastases compared to needle biopsy under the specific experimental conditions of this study.

Animals↗

PubMedDate not supplied

Conjugates of mitomycin C with the immunoglobulin M monomer fragment of a monoclonal anti-MM46 immunoglobulin M antibody with or without serum albumin as intermediary.

In studies on antitumor antibody-drug conjugates as potential antitumor agents with improved tumor specificity, conjugates of mitomycin C (MMC) with the IgMs fragment of a monoclonal IgM antibody to a tumor-associated antigen (MM antigen) on mouse mammary tumor MM46 cell (anti-MM46 IgMs) were prepared by direct and bovine serum albumin (BSA)-mediated indirect conjugation. MMC was linked to the IgMs and BSA by the use of 1a-[4-(N-succinimidoxycarbonyl)butyryl]mitomycin C, which allowed the slow release of MMC. In the indirect conjugation, the thiol group of BSA was first protected as the 2-pyridyldithio group and, after the MMC binding, regenerated with dithiothreitol, and the resulting BSA-MMC was reacted with the IgMs having the maleimide group introduced with N-succinimidyl m-(N-maleimido)benzoate. Anti-MM46 IgMs-MMC was more cytotoxic against the target MM antigen-positive but Thy 1.2 antigen-negative MM46 cells than control anti-Thy 1.2 IgM-MMC. No such selective cytotoxicity was observed between anti-MM46 IgMs-MMC and anti-Thy 1.2 IgMs-MMC against the MM antigen- and Thy 1.2 antigen-negative MM48 cells. Anti-MM46 IgMs-BSA-MMC was more cytotoxic against MM46 cells than was a mixture of unconjugated anti-MM46 IgMs and BSA-MMC.

Animals↗