Involvement of aquaporin in thromboxane A2 receptor-mediated, G12/13/RhoA/NHE-sensitive cell swelling in 1321N1 human astrocytoma cells

The physiological role of the thromboxane A₂ (TXA₂) receptor expressed on glial cells remains unclear. We previously reported that 1321N1 human astrocytoma cells pretreated with dibutyryl cyclic AMP (dbcAMP) became swollen in response to U46619, a TXA₂ analogue. In the present study, we examined the detailed mechanisms of TXA₂ receptor-mediated cell swelling in 1321N1 cells. The cell swelling caused by U46619 was suppressed by expression of p115-RGS, an inhibitory peptide of Gα_12/13 pathway and C3 toxin, an inhibitory protein for RhoA. The swelling was also inhibited by treatment with Y27632, a Rho kinase inhibitor and 5-(ethyl-N-isopropyl)amiloride (EIPA), a Na⁺/H⁺-exchanger inhibitor. Furthermore, cell swelling was suppressed by the pretreatment with aquaporin inhibitors mercury chloride or phloretin in a concentration-dependent manner, suggesting that aquaporins are involved in U46619-induced 1321N1 cell swelling. In fact, U46619 caused [³H]H₂O influx into the cells, which was inhibited by p115-RGS, C3 toxin, EIPA, mercury chloride and phloretin. This is the first report that the TXA₂ receptor mediates water influx through aquaporins in astrocytoma cells via TXA₂ receptor-mediated activation of Gα_12/13, Rho A, Rho kinase and Na⁺/H⁺-exchanger.     

RNA-Induced Interference with Animal Virus Infection

Some RNAs, including both single- and double-stranded RNAs, when incubated with chick embryo cell culture induce cellular resistance against viruses. Evidence was now obtained indicating that the induction of cellular resistance by RNA depends on the cellular metabolic activity, especially on the synthesis of cellular RNA and protein. Thus, inhibitors of RNA and protein synthesis, actinomycin D and cycloheximide, were found to inhibit the development of an antiviral state when added before, or during the relatively early period of, incubation of the cells with RNA. In the course of induction of cellular resistance, three stages may be distinguished, the priming stage, the developing stage, and the established resistant stage.     

Anaerobic biodegradability of polyvinyl alcohol

Summary Biodegradability of polyvinyl alcohol (PVA) under anaerobic conditions was demonstrated using anaerobic river sediments and anaerobically treated activated sludge from a sewage treatment plant. PVA having molecular weights of 2000 and 14000 was over 60% biodegraded as determined by TOC.     

Humans but Not Chimpanzees Vary Face-Scanning Patterns Depending on Contexts during Action Observation

Human and nonhuman primates comprehend the actions of other individuals by detecting social cues, including others’ goal-directed motor actions and faces. However, little is known about how this information is integrated with action understanding. Here, we present the ontogenetic and evolutionary foundations of this capacity by comparing face-scanning patterns of chimpanzees and humans as they viewed goal-directed human actions within contexts that differ in whether or not the predicted goal is achieved. Human adults and children attend to the actor’s face during action sequences, and this tendency is particularly pronounced in adults when observing that the predicted goal is not achieved. Chimpanzees rarely attend to the actor’s face during the goal-directed action, regardless of whether the predicted action goal is achieved or not. These results suggest that in humans, but not chimpanzees, attention to actor’s faces conveying referential information toward the target object indicates the process of observers making inferences about the intentionality of an action. Furthermore, this remarkable predisposition to observe others’ actions by integrating the prediction of action goals and the actor’s intention is developmentally acquired.     

Revision of the theory of phototropism in plants: a new interpretation of a classical experiment

Went's classical experiment on the diffusion of auxin activity from unilaterally illuminated oat coleoptile tips (Went 1928), was repeated as precisely as possible. In agreement with Went's data with theAvena curvature assay, the agar blocks from the illuminated side of oat (Avena sativa L. cv. Victory) coleoptile tips had, on an average, 38% of the auxin activity of those from the shaded side. However, determination of the absolute amounts of indole-3-acetic acid (IAA) in the agar blocks, using a physicochemical assay following purification, showed that the IAA was evenly distributed in the blocks from the illuminated and shaded sides. In the blocks from the shaded and dark-control halves the amounts of IAA were 2.5 times higher than the auxin activity measured by theAvena curvature test, and in those from the illuminated half even 7 times higher. Chromatography of the diffusates prior to theAvena curvature test demonstrated that the amounts of two growth inhibitors, especially of the more polar one, were significantly higher in the agar blocks from the illuminated side than in those from the shaded side and the dark control. These results show that the basic experiment from which the Cholodny-Went theory was derived, does not justify this theory. The data rather indicate that phototropism is caused by the light-induced, local accumulation of growth inhibitors against a background of even auxin distribution, the diffusion of auxin being unaffected.Abbreviation IAA indole-3-acetic acid     

A case of sporotrichosis caused by two genetically differentSporothrix schenckii strains

A survey for the natural occurrence of Fusarium mycotoxins, deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN), in Dutch cereals (totaling 29 samples) harvested in 1984/1985, showed that 90%, 79% and 62% of samples were contaminated with DON, NIV and ZEN, respectively. Average contents (ng/g) in the total of positive samples were 221 (DON), 123 (NIV) and 61 (ZEN). Among the cereals examined, the highest concentrations (ng/g) was 3198 (DON), 1875 (NIV) and 677 (ZEN) in a yellow corn sample for animal feed. The results of this survey show that Dutch cereals were relatively significantly contaminated with Fusarium mycotoxins.     

Analysis of restriction profiles of Mitochondrial DNA from Sporothrix schenckii and related fungi

Restriction profiles by HaeIII of mitochondrial DNA were studied for classification and distinction of Sporothrix schenckii (100 strains), S. schenckii var. luriei (1), S. curviconia (1), S. inflata (7), Ceratocystis stenoceras (17) and C. minor (7). These 6 species showed unique restriction profiles which could be discriminated from each other. S. schenckii was further separable into 11 types, S. inflata into 4 types, C. stenoceras into 4 types and C. minor into 7 types based on restriction profile heterogeneity.     

Structural changes of alpha2- and ovomacroglobulins

The plasma α₂-macroglobulin and its egg white homologue ovomacroglobulin were purified from several different species and their structure before and after the reaction with proteinases studied by electron microscopy. The negatively stained specimens showed either a ringlike structure or a flowerlike one before the reaction with proteinses, but their structures changed into open rectangular ones after the reaction. The translational frictional ratio f/f ₀ of human α2-macroglobulin and crocodilian ovomacroglobulin given in the literature is between 1.5 and 1.6 before and after the reaction with proteinases. The value reflects asymmetry due not to a high axial ratio, but rather to an openness of the structure resulting in a partially free draining character of the molecules. The computational method developed by Bloomfield and his co-workers based on the formalism of Kirkwood is used to calculate the frictional ratio of several models constructed from small spheres. The overall shape of the models is derived from electron micrographs. Although the degree of hydration is an unknown parameter in the calculation, reasonable agreement is obtained between the experimental values of f/f ₀ and the calculated ones. Combination of electron microscopic and hydrodynamic methods would be fruitful in the structural study of giant proteins such as α₂-macroglobulin.     

Immunotherapy with bestatin for acute nonlymphocytic leukemia in adults

Summary In a cooperative randomized control study of immunotherapy with bestatin in combination with chemotherapy in adults with acute nonlymphocytic leukemia (ANLL), 101 patients (48 in the bestatin group and 53 in the control group) out of 115 patients registered were evaluated as eligible. The bestatin group achieved a statistically significant prolongation of survival compared with the control group in overall ANLL and acute myelogenous leukemia. In the analysis of patient age, the bestatin group achieved a statistically significant prolongation of both the remission duration and survival in patients aged 50 to 65 years, while the differences were not significant in the 15 to 49 age group. The bestatin group tended to achieve a higher rate of reinduction of remission in patients who had recurrence of leukemia. Side effects developed in only 5 (9.6%) of 52 patients treated with bestatin. None of these side effects were particularly serious in nature. It is concluded that bestatin is useful for prolongation of survival of adult patients with ANLL, making for a longer remission duration especially in elderly patients and with few side effects.     

Chemiluminescent assay of various enzyme activites and its application to enzyme immunoassays

A highly sensitive chemiluminescent assay for NAD(P)H have been developed. The principle of the method is as follows; NAD(P)H reduces molecular oxygen to superoxide anion (O) and hydrogen peroxide (H₂O₂) in the presence of 1-methoxy-5-methylphenazinium methyl sulphate (1-MPMS) as electron mediator. The produced O and H₂O₂ can be measured by chemiluminescent reaction using isoluminol (IL) and microperoxidase (m-POD). A linear relationship between chemiluminescence intensity and NAD(P)H concentration (log/log) was obtained ranged from 10^?9 mol/I to 10^?5 mol/I. This chemiluminescent reaction has been coupled to the assay of glucose-6-phosphate dehydrogenase (G6PDH), β-D -galactosidase (β-Gal) and alkaline phosphatase (ALP). The detection limits of G6PDH, β-Gal and ALP were 10^?18 mol, 10^?20 mol and 10^?18 mol per assay, respectively. The chemiluminescent assay of these enzymes applied to chemiluminescent enzyme immunoassay for 17α-hydroxy-progesterone and DNA hybridization assay using these enzymes as label.