B-cell nature malignant lymphoma probably caused by EB-virus infection

In cells in a haemopericardium associated with a B-cell malignant lymphoma, immature herpes type virus particles were found by electron microscopy. Epstein-Barr virus associated nuclear antigen (EBNA) and virus capsid antigen (VCA) were also found, both in the tumor cells, in the bloody pericardial fluid and in cultivated cells. Serological studies revealed high anti-toxoplasma antibody levels both in the pericardial fluid and in serum. Both EB virus and toxoplasma infections are assumed to have played an important role on the pathogenesis of the present case.

Detection of Epstein-Barr virus in biopsied malignant lymphoma cell and its continuous culture

In more than 80% of tumor cells in the pericardiac effusion of a case of malignant B-cell lymphoma, Epstein-Barr virus-determined nuclear antigen (EBNA) was detected by the anticomplement immunofluorescence test. Moreover, herpestype virus particles, although few in number, were demonstrated in the nucleus of lymphoma cells by an electron microscope. Tumor cells in the pericardiac effusion were seeded at 98% purity after centrifugation on Ficoll-Conray and, soon after plating, they proliferated continuously without any lag phase of growth or cell death. Therefore, the established cell line was regarded as of tumor cell origin and named Fujimaki-II cell after patient's name. On the other hand, Fujimaki-I cells were established from the biopsied tumor in the same way. These two cell lines, B-lymphocyte in nature, had both EB virus-related antigens and herpes-types virus particles. Heterotransplantation of cultured cells and tumor tissue obtained at autopsy into athymic nude mice was not successful. Transformation of cord blood lymphocytes by the virus released from Fujimaki-II cell also failed. This might be the first case of non-Burkitt type lymphoma in which the EB virus genome was directly detected in the tumor cells.

Genetic mapping of the F plasmid gene that promotes degradation of stable ribonucleic acid in Escherichia coli

F+ Escherichi coli cells that contain an srnA mutant allele degrade their stable ribonucleic acid (RNA) extensively after RNA synthesis is blocked at 42 degrees C. The relevant gene promoting degradation of stable RNA, srnB+, or its promoter was mapped between 1.7 and 2.8 kilobases on the F plasmid by using deleted F' plasmids and chimeric plasmids composed of pSC101 and fragments of F plasmid.

Gene affecting longevity of messenger RNA: a mutant of Escherichia coli with altered mRNA stability

We have screened 897 temperature sensitive growth mutants of E. coli for mutant strains showing longer mRNA half-life. The fate of pulse-labelled RNA was examined at 42 degrees C after cessation of RNA synthesis and with prior exposure to nonpermissive temperature (42 degrees C). Eight stains showed altered turnover of RNA (presumably mRNA), and further analysis on mutant strain JE15144 indicated that the stability of pulse-labeled RNA as well as of tryptophan (trp) mRNA increased four to seven fold over its parental strain at 42 degrees C. At 4 min or 10 min after addition of rifampicin, some 70 to 80% of polyribosome in the growing cells could still be conserved in JE15144 cultured at the nonpermissive temperature while little, if any, polyribosomes remained in its parental strain (PA3092) under the same condition. Two generation times were required for complete stoppage of growth of this mutant strain after shifting to 42 degrees C, and protein synthesis continued at a significant, but slightly reduced, rate at 42 degrees C. However, functional decay of mRNA in the mutant strain, with respect to the capacity for producing peptides, appeared to be similar to the parent strain, with half-lives of 3.5 min in PA3092 and 4.7 min in JE15144.

Detection of mutagenic activity in particulate air pollutants

Ames's strains of Salmonella typhimurium were used to evaluate the mutagenic activity of airbone particulate materials collected at six different points in the industrial area of Ohmuta and the residential area Fukuoka. Tests were done in presence of rat-liver S-9 fraction isolated from rats that had been treated with Aroclor 1254. When the number of revertant colonies per plate was plotted against the amount of methanol extract of particulate air pollutants, using strain TA98, approximately linear relationships were observed for active samples. Generally, mutagenic activity of the samples increased in proportion to the density of air pollutants. In our system, 38--349 microng of methanol extract, from 0.225--4.51 m3 of air from the factory districts in Ohmuta City gave 100 his+ revertants per plate. On the other hand, 54--2300 microng of air pollutants, from 1.29--14.1 m3 of air from the residential districts in Fukuoka City, gave a comparable activity. Every sample from each area had mutagenic activity. Chemicals in air pollutants were fractionated by alumina column chromatography and identified by gas chromatography and mass spectrometry. More than 28 compounds, including 12 unknown substances were identified as polycyclic hydrocarbons. Twelve of these compounds are already known to be carcinogens and to induce reversions to histidine independence in strain TA98 of Salmonella.

The histogenesis of retinoblastoma. An electron-microscopic analysis of rosette

The histogenesis of retinoblastoma has long been a constantly debatable problem since the last century. Rosettes of retinoblastoma have been studied by electron microscopy using 15 eyes as speciments. The evidences suggest that the rosette is at least composed of visual cells and glial (possibly Müller) cells, providing characteristics of the primitive retina. Therefore, it has been concluded that retinoblastoma does not arise from either of the developing neuronal or glial cells, but from the multipotential embryonic retinal cell which is capable of being differentiated into either of these two cellular systems.

Double beam fluorescence spectrophotometer: design and typical applications

A double beam fluorescence spectrophotometer has been designed for the analytical control laboratory and for some research applications. It has several modes of operation in addition to double beam, in which the difference in fluorescence between two samples is measured. The design concept (developed by Ohnishi) employs equivalent optical paths for both beams, an optical chopper, and a time sharing electrooptical system. Since it is a true double beam system it may also be used to record the percent transmission spectrum of a sample, which is placed in monochromatic light, as both excitation and emission monochromators are scanned synchronously. For identification of pure samples in dilute solutions a relative quanta excitation spectrum may also be recorded. Some applications for the double beam fluorescence concept are to improve quantitative results by eliminating interference due to scatter and due to unwanted fluorescence peaks, to control product quality by matching two samples of similar characteristics and to assay trace organic compounds.