Paradoxical enhancement of interleukin-2-mediated cytotoxicity against K562 cells by addition of a low dose of methotrexate

Summary In vitro effects of methotrexate (MTX) on interleukin-2(IL-2)-mediated cytotoxicity of peripheral blood mononuclear cells (PBMC) were studied. PBMC were incubated with human recombinant IL-2 (25 U/ml) for 72 h; during the last 24 h, various concentrations (10 pM–1 µM) of MTX were added to the culture. Cytotoxicity against k562 cells was measured by a 4-h⁵¹Cr-release assay. The IL-2-mediated cytotoxicity was paradoxically increased at around a concentration (10 nM) MTX. Such a low concentration of MTX showed no anti-proliferative effect on cell growth. This enhancement with 10 nM MTX was shown only in an E-rosette⁺ (E⁺) population, but not in E-rosette^– (E^–). In addition, when E⁺ cells were treated with an anti-CD16 monoclonal antibody plus complement after incubation with IL-2 and MTX, MTX-induced enhancement was lost, suggesting that an E⁺CD16⁺ cell population was mainly involved in this augmentation. Positively sorted E⁺CD16⁺ cells showed similar enhancement of cytotoxicity after treatment with IL-2 plus MTX. On the other hand, MTX treatment did not show the phenotypical changes including of the E⁺CD16⁺ cells, indicating that this treatment did not affect the differentiation and proliferation of the specific cell subset. Our results indicate that a low dose of MTX could have a role in the regulation of immunological anti-cancer surveillance systems through the natural killer and lymphokine-activated cytotoxic cells.This work was supported in part by a Grant-in-Aid for Cancer Research (1–10) from the Ministry of Health and Welfare in Japan     

Distribution of the pulmonary artery and vein of the orangutan lung

The distribution of the pulmonary artery and vein of the orangutan lung was examined. The right pulmonary artery runs obliquely across the ventral side of the right bronchus at the caudally to the right upper lobe bronchiole. It then runs across the dorsal side of the right middle lobe bronchiole. Thereafter it runs obliquely across the dorsal side of the right bronchus, and then along the dorso-medial side of the right bronchus. This course is different from that in other mammals. During its course, it gives off branches which run mainly along the dorsal or lateral side of each bronchiole. The left pulmonary artery runs across the dorsal side of the left middle lobe bronchiole, then along the dorso-lateral side of the left bronchus, giving off branches which run along each bronchiole. The pulmonary veins run mainly the ventral or medial side of, along or between the bronchioles. In the left lung, the left middle lobe vein has two trunks; one enters the left atrium, and the other enters the left lower lobe pulmonary venous trunk. This is also different from that found in most mammals. Finally, the pulmonary veins enter the left atrium with four large veins.     

Degradation of Dehydrodivanillin by Anaerobic Bacteria from Cow Rumen Fluid

Dehydrodivanillin (DDV; 0.15 g/liter) was biodegradable at 37°C under strictly anaerobic conditions by microflora from cow rumen fluid to the extent of 25% within 2 days in a yeast extract medium. The anaerobes were acclimated on DDV for 2 weeks, leading to DDV-degrading microflora with rates of degradation eight times higher than those initially. Dehydrodivanillic acid and vanillic acid were detected in an ethylacetate extract of a DDV-enriched culture broth by thin-layer, gas, and high-performance liquid chromatographies and by mass spectrometry.     

Histochemical detection of DNA strand scissions in mammalian cells by in situ nick translation

A method to visualize in situ of single strand scissions of DNA in fixed mammalian cells has been developed. Using the nuclear nick translation with biotin-labeled dUTP followed by binding to avidin-biotin-peroxydase complex, the nuclei of HeLa cells which had been treated with a DNA-damaging antibiotic bleomycin were specifically stained, implicating that the histochemical detection of single strand scissions (nicks) of DNA in fixed cells was completed without destroying the morphology, and without using autoradiography.     

Binding of cobalamin analogs to intrinsic factor-cobalamin receptor and its prevention by R binder

It is now known that nonphysiological cobalamin analogs exist in the gastrointestinal tract, but their metabolic behavior is unclear. In this study, [57Co]cobinamide was used to study its affinity to hog intrinsic factor-cobalamin (IF-Cbl) receptor which has no species specificity against human IF-Cbl receptor, and its relation to human saliva R binder. Cobinamide was prepared from [57Co]cyanocobalamin and separated by paper chromatography. Human IF-Cbl complex was bound to IF-Cbl receptor but free cyanocobalamin was not. Although R binder-cobinamide was not bound to the IF-Cbl receptor, free cobinamide was bound to the IF-Cbl receptor to a significant extent (about one-half of IF-cyanocobalamin binding to the IF-Cbl receptor). We then investigated the binding of cobinamide to R binder and trypsin-treated R binder. Association constant of cobinamide binding to the IF-Cbl receptor was 1.0 X 10(9) M-1 which was much lower than that of cobinamide binding to trypsin-treated R binder and to untreated R binder. Further study indicated that cobinamide binding to the IF-Cbl receptor was blocked by the addition of R binder and also by trypsin-treated R binder. We conclude that one of the roles of R binder is to prevent binding of free cobalamin analogs to the IF-Cbl receptor in the gut.     

Long-term follow-up study of rostral mesencephalic reticulotomy for pain relief--report of 34 cases

A long-term follow-up study of rostral mesencephalic reticulotomy (RMR) for pain relief is presented. 34 patients (24 males and 10 females) were operated. Ages ranged from 18 to 65 years. The follow-up period was 1-70 months. The overall effectiveness of RMR showed good relief of pain in 23 patients (67%). The study of effectiveness of RMR according to type of pain showed good relief of pain in 5 out of 6 patients (83%) with nondenervation pain, whereas satisfactory pain relief was obtained in 18 out of 28 patients (64%) with denervation pain.     

Regulatory Mechanisms of Reproductive Effort in Plants II. Plasticity in Reproductive Energy Allocation and Propagule Output of Glycine max Merr. (Leguminosae) Cultivated at Varying Densities and Nitrogen Levels

Abstract Plasticity in growth, reproductive energy allocation (RA), and reproductive output were studied in Glycine max Merr. Cv. Enrei (Leguminosae) grown under varying densities and soil nitrogen levels.
Marked plastic responses were detected in individual biomass, the patterns of resource allocation to total reproductive structures (RA) and also to propagules, reproductive outputs, and propagule weight under changing densities and soil nitrogen levels. Plants cultivated at higher densities exhibited proportionately lower individual biomass, lower RA, lower seed output, and smaller seed size in response to increasing density and decreasing soil nitrogen levels, although some deviations were observed, especially in the highest density plot with no fertilization. Differences due to different N-levels were not as great as those to changing density, which may in part be due to the fact that soybean has nitrogen-fixing bacteria in root tubercles, just as in any other Leguminosae. Fecundity was also maintained at the similar high rates of 80–97% in all plots examined, although slight but steady decreases were noted with increasing density. This resemblance in fecundity may be due to its strong inbreeding system.
Another important finding was that seed production under limited resource availability, notably lack of ample solar radiation due to strong interference at higher density plots, is exceedingly costly. This was most clearly exhibited by a sharp increase in relative energy partitioning to a single propagule in response to the increased density, the relative energy cost to a single propagule (RA) increasing from one to seven-fold. The results obtained in this study coincide well with the findings made in other plants, e.g., Helianthus annuus, Oryza sativa , and Coix ma-yuen , with the same experimental designs.     

Light microscopic localization of hepatic fatty acid binding protein mRNA in jejunal epithelia of rats using in situ hybridization, immunohistochemical, and autoradiographic techniques

An in situ hybridization technique using a [35S]-labeled oligonucleotide probe was employed, in combination with immunohistochemistry and autoradiography, to examine gene expression for hepatic fatty acid binding protein (FABP) in the jejunal epithelia from both fed and fasted rats. In rats fed ad libitum, immunoreactivity and mRNA signal for FABP were localized to the absorptive epithelial cells lining the villus, whereas they were absent in the crypt epithelial cells. The level of FABP mRNA was relatively low in the tip of the villus, although FABP immunoreactivity remained high in this area. Animals fasted for 3 days exhibited a downward shift of the lower boundary of the FABP-expressing cell population into the middle portion of the crypt, in terms of the immunoreactivity and the mRNA signal. The proliferative cell compartment of the crypt, as revealed by [3H]-TdR incorporation, showed no substantial change in size between the fed and fasted states. The present results provided evidence that (a) during the differentiation and upward migration of the absorptive epithelial cells, the expression of FABP gene begins at the crypt-villus junction and declines before the cells reach the villus tip, and (b) fasting induces an earlier expression of the FABP gene in the maturing crypt epithelial cells.