Hydrolysis and protection from hydrolysis of enkephalins in human plasma

Seven groups of enkephalin-degrading enzymes and three groups of inhibitors active on these enzymes were separated from human plasma. The activity of the enzymes in hydrolyzing enkephalins and of the inhibitors in protecting enkephalins from proteolysis was measured. Results obtained with the endogenous inhibitors were compared to those relative to synthetic inhibitors. Data obtained indicate that all enkephalin-degrading enzymes found in plasma are significantly inhibited by the endogenous substances present in this tissue. The inhibition of the different classes of plasma enzymes by two of the three groups of endogenous substances is quite uniform, while one group of inhibitors appears specific to dipeptidylpeptidases. Results obtained are discussed in terms of the functional role of the inhibitory substances and of the possible pharmacological implication of their presence in human plasma.     

Diffusione pollinica e caratteristiche immunologiche e broncoreattive di soggetti atopici in Pietra Ligure (Savona)

Riassunto Sono state rilevate durante un monitoraggio aerobiologico effettuato a Pietra Ligure (Savona) nel corso del 1987 le concentrazioni polliniche di 50 taxa ed è stata valutata l'influenza relativa dei fattori meteorologici. Le osservazioni palinologiche sono state rapportate alle concentrazioni sieriche delle IgE specifiche, alla reattività bronchiale specifica ed aspecifica valutate in 101 pazienti allergici (rinitici ed asmatici), sensibilizzati a Graminaceae ed Urticaceae (Parietaria) al fine di riconoscere correlazioni tra le caratteristiche aerobiologiche di questi allergeni edi meccanismi patogenetici che sostengono la reattività bronchiale.      

Identifiability from parameter bounds. Structural and numerical aspects

Some a priori and a posteriori aspects of the identifiability problem for unidentifiable models are discussed. It is argued that the nation of identifiability from parameter bounds has a minor a priori structural relevance. The parameter bounds rationale may prove a useful a posteriori numerical notion. However, its practical potentiality needs careful evaluation, as the use of point estimates automatically builds into the model some hidden structural constraints. Examples are given.     

Effect of carbon dioxide on differentiation and on the level of a soluble b-type cytochrome in Phycomyces blakesleeanus

A soluble b-type cytochrome has been detected and partly characterized in mycelial extracts of Phycomyces blakesleeanus. As it is already known, CO₂ delays sporangiophorogenesis, but it also lowers the level of this cytochrome. A possible causal relationship between sporangiophorogenesis and the b-type-cytochrome level may exist. There is some correlation between the extent of the delay of sporangiophorogenesis and of the decrease in cytochrome-b level in wild type and mutants that are either resistant or sensitive to CO₂.     

Electric stimulation of the dental pulp in the evaluation of the central effect of analgesics

We conducted a double-blind cross-over study in ten volunteers aged from 19 to 30 years, to compare the pain control effects of a single oral dose of two analgesic compounds (drug A: propyphenazone mg 250, ethylmorphine mg 5, caffeine mg 5; drug B: dipyrone mg 500, diphenhydramine mg 12.5, adiphenine mg 5, ethyl aminobenzoate mg 2.5) in an experimental pain model using stimulation of dental pulp. Constant voltage stimuli were delivered through silver chloride electrodes placed in contact with the vestibular surface of the upper medial incisor. At the beginning of the session, the pain input was graded by asking the subject to identify the weakest stimulus perceived (threshold level) and the strongest stimulus endurable (tolerance level). The range between threshold and tolerance level was divided in nine steps plus a subliminal step. The ten steps were delivered randomly, and each series of steps was repeated eight times. The subjects were instructed to rate the pain sensation in an arbitrary scale of 5 degrees. The procedure was repeated at 60 min and 180 min after drug administration. Each subject received two tablets of drug A or drug B in two different sessions at weekly intervals. Statistical analysis of the procedures showed that neither drug A nor drug B significantly affected the pain threshold. Drug A significantly reduced the total pain score (P less than 0.01) and its action peaked 60 min after administration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mouse polyomavirus mediated effects on the infected cell membrane studied by dielectric spectroscopy

The effect of polyomavirus on the infected cell has been investigated by dieclectric spectroscopy. This technique has a great potential in the study of the ion transport properties of the cell membrane. The results presented in this communication suggest a correlation between progression of the viral infection and dielectric features of the infected, cell plasma membrane.     

Identification of a nucleo-cytoplasmic ionic pathway by osmotic shock in isolated mouse liver nuclei

Summary The observation that the nuclear envelope outer mem brane contains ion channels raises the question of whether these conductances communicate between the cytosol and the nuclear envelope cisternae or between the cytosol and the cytoplasm. Failure to detect large, nonselective holes using the patch-clamp technique has led to the speculation that ion channels and nuclear pores are in fact the same. In this paper we present evidence that the ionic channel, recorded in isolated liver nuclei with the patch-clamp configura tion of “nucleus-attached,” spans the double membrane of the envelope, providing a direct contact between nucleoplasm and cytoplasm.     

Circadian organization in the ruin lizard Podarcis sicula: the role of the suprachiasmatic nuclei of the hypothalamus

The effects of electrolytic lesions to the suprachiasmatic nuclei of the hypothalamus (SCN) on circadian rhythms of locomotor activity were examined in ruin lizards Podarcis sicula maintained in constant darkness and constant temperature (29°C). All lizards (N=15) in which the lesion damaged 80% or more of the SCN became behaviorally arrhythmic. On the contrary, locomotor rhythms persisted in all cases (N=11) when the SCN remained intact and lesions were confined to neighbouring regions of the preoptic area. Taken together with previous work which demonstrates that the pineal and the retinae are not essential for the persistence of circadian locomotor rhythmicity in Podarcis sicula and with recent evidence showing the homology between the SCN of lizards and those of mammals the present results strongly support the view that the SCN of Podarcis sicula contain the primary pacemaker(s) for locomotor rhythms.Abbreviations DD constant darkness - LL constant light - SCN suprachiasmatic nuclei of the hypothalamus - PH nucleus periventricularis hypothalami - OC optic chiasm - te length of circadian activity - freerunning circadian period     

R-factor-mediated suppression of the galactose-sensitive phenotype of Escherichia coli K-12 galE mutants

Plasmids S-a and Rts1 suppress the galactose-sensitive phenotype of galE mutants of Escherichia coli K-12, giving rise to both galactose-fermenting and nonfermenting strains. Fermenting strains produce normal inducible UDP-galactose epimerase. Plasmids extracted from either a fermenting or a nonfermenting strain are indistinguishable when examined by either measurements of length of relaxed circular molecules by electron microscopy or electrophoretic pattern of restriction endonuclease digestion products. The phenomenon could be explained by reversible recombination between a plasmid-borne epimerase gene and homologous chromosomal sequences.