Therapy of bovine ocular squamous-cell carcinoma with local doses of interleukin-2: 67% complete regressions after 20 months of follow-up

We have tested the therapeutic potency of peritumorally injected low doses of interleukin-2(IL-2). Seventy tumours of the bovine ocular squamous-cell carcinoma (BOSCC), 1–3 cm in diameter, were treated with 5000, 20 000 or 200 000 U IL-2 from Eurocetus (Chiron) to find the optimal dose for treatment. Injections were given peritumorally on Monday to Friday on 2 consecutive weeks. The size of the tumours was measured before treatment and 1, 3, 4, 9 and 20 months after treatment. After 9 months complete regression was observed in 89% of the tumours treated with 5000 U IL-2, 80% treated with 20 000 U and 67% treated with 200 000 U. After 20 months, there was complete regression of 35%, 31% and 67% of the tumours respectively. The 9-and 20-month results of the 200 000-U treatment are significantly better than those of the 5000-U and 20 000-U treatments taken together. This protocol may be useful to treat advanced inoperable tumours (e.g. of the nasopharynx or skin) of human patients.     

Chiroptical methods in conformational analysis

CD spectra of flexible organic molecules in solution are normally very sensitive to conformation. In a system composed of two or more chromophores joined by one or more single bonds and with one fixed or strongly preferred conformation, it is often possible to reproduce the CD spectrum by semiempirical calculations based on interactions between the electronic transitions in the respective chromophores. In a system containing two or more conformations of appreciable weight, the observed CD spectrum is the superposition of those of the individual conformations and has to be analyzed in terms of the individual calculated spectra and the relative energies of the respective conformations. The effect of temperature variation on conformational equilibria and on the composite CD spectra will be discussed and exemplified. © 1995 Wiley-Liss, Inc.     

Identification of 6-acetyl-7-methyl-7,8-dihydropterin as a degradation product of 5,10-methenyl-5,6,7,8-tetrahydromethanopterin

During purification procedures and upon aerobic heating with alkali a green-yellow degradation fluorescent product (GY) was formed from 5,10-methenyl-5,6,7,8-tetrahydromethanopterin, an intermediate in the reduction of CO₂ to methane [J. T. Keltjens, L. Daniels, H. G. Janssen, and G. D. Vogels (1983)Eur. J. Biochem.130, 545–552]. GY was suggested to be a 6-(1-oxo)-7,8-dihydropterin. On the basis of the spectral properties and the results of degradation studies, it was now shown that the structure of GY is 6-acetyl-7-methyl-7,8-dihydropterin. This structure was confirmed by synthesis of the compound and other reference substances.     

Plant regeneration from cotyledonary tissue of Glycine canescens,a perennial wild relative of soybean

Cotyledonary tissue from immature embryos of Glycine canescens was induced to callus and then form embryo-like structures. These structures could be cultured into whole plants and grown in soil.     

Migration of leafhoppers (Homoptera: Auchenorrhyncha) into a new polder

Auchenorrhyncha of a new polder were sampled by different kinds of traps in four stations in new habitats, one station on the salt marsh and one just outside the polder. In the latter stations 20 species of Auchenorrhyncha were caught in numbers that declined during the four year study. The proportion of macropters of the common Streptanus sordidus was highest in the largest catches. In the polder proper 392 specimens of 13 species were caught, all had moved at least 1500 m, but some could be traced to origins at greater distances. The number of immigrants also declined during the study. The distribution of the leafhoppers over the trapping stations suggests that leafhoppers, although sometimes transported over great distances, as a rule quickly fall out once they are airborne. Probably only one species had founded a resident population in the new polder at the end of the study.     

Monoacylcadaverines in the blood of schizophrenic patients

Concentrations of cadaverine, monoacetylcadaverine and monopropionylcadaverine in the blood of schizophrenic and nonschizophrenic subjects were measured. Two groups, one from the U.S.A. the other from Japan, were tested. Monoacetylcadaverine and monopropionylcadaverine were found elevated in the blood of some schizophrenic patients in comparison with those in controls in each group. Their increase could be caused by a reduced monoamine oxidase activity or by an increased acylation in schizophrenic patients.     

Effect of rye embryo ribosome nuclease on double-stranded RNA

In extracts obtained by treating rye embryo ribosomes with 0.5 M NH₄Cl, nuclease activity was noted towards double-stranded RNA from virus of Penicillium chrysogenum and towards synthetic poly (A)-poly (U) and poly (I)-poly (C) complexes.     

Abundance of protein-bound sulfhydryl and bisulfide groups at chromosomal nucleolus organizing regions

Silver stainability of the chromosomal nucleolus organizing regions that contain the structural genes for ribosomal RNA can be abolished by proteolytic and oxidative treatments. Histone extraction has no effect. This indicates that reducing groups of non-histone chromosomal proteins are responsible for silver staining. Treatment with fluorescent sulfhydryl and disulfide specific reagents followed by silver staining demonstrates coincidence of silver dots and brightly fluorescent spots at the short arms of human acrocentric chromosomes where ribosomal RNA-genes are located. After treatment with cupric sulfite reagent in the presence of urea fluorescence and silver staining was no longer possible. Silver staining has been reported to be associated with ribosomal RNA-gene activity. Acrocentric chromosomes that are negative in silver staining also lack the brightly fluorescent spots. Therefore, we conclude that an abundance of protein-bound sulfhydryl and disulfide groups occur at nucleolar organizing regions with active genes. Differentially fluorescing spots could not be observed after staining with fluorescamine. So, either the sulfhydryl reagents used in this study are much more sensitive than fluorescamine to study protein distributions in cytological preparations, or our observations point to a local accumulation of some specific protein(s) rich in sulfhydryls. The presence of many sulfhydryl and disulfide groups at the nucleolus organizing regions seems suggestive of a great flexibility of protein(s) by transition of sulfhydryl groups to disulfide bridges and vice versa at these highly active regions of the genome.     

A simple mathematical model of the secondary succession of shrubs

A simple simulation model of the secondary shrub succession has been elaborated on the grounds of primary field data from abandoned fields of different ages in the area of Bohemian Karst. The model describes vegetational dynamics using adaptedVolterra-Lotka equations for competing species. Carrying capacities and growth rates are expressed as a function of the depth of the soil.