Showing papers by "University of Naples Federico II published in 1973"
91 citations
TL;DR: Results show that epithelial budding is very sensitive to the treatment with the azetidine-2-carboxylic acid, and draw attention to collagen biosynthesis as one of the possible mechanisms by which the mesenchyme controls the spatial organization of the epithelial tree.
Abstract: A proline analogue, azetidine-2-carboxylic acid, which has been reported to selectively depress collagen biosynthesis, affects lung morphogenesis in vitro by determining differential modifications of the rate of epithelial growth and ramification activity.
Low concentrations of the analogue induce a sharp decline of the number of newly formed terminal buds, leaving the rate of global growth of the epithelial tree almost unaffected. This effect is reversed by increasing doses which appear more effective on global epithelial growth than on budding. DNA and protein content at the end of the treatment are unequally reduced. Protein concentration is more depressed with consequent rise of the DNA/protein ratio.
These results show that epithelial budding is very sensitive to the treatment with the analogue, and draw attention to collagen biosynthesis as one of the possible mechanisms by which the mesenchyme controls the spatial organization of the epithelial tree. This type of control appears relatively independent on the actual rate of epithelial cell replication, since budding is much more sensitive to the action of the drug.
48 citations
TL;DR: A patient who showed hepatic granulomas in the course of an episode of hydralazine disease is described, and cessation of the drug resulted in regression of both the liver condition and hydralazines disease.
43 citations
TL;DR: The stress-strain behavior of ABS containing up to 33.5vol% of 10-40μm glass beads as filler was measured at one strain rate at room temperature as discussed by the authors.
39 citations
TL;DR: Melanosomes of phyllomedusid frogs are unusually large and are composed of an amorphous matrix of thick fibers, and it is suggested that these chromatophores are innervated.
Abstract: Melanosomes of phyllomedusid frogs are unusually large and are composed of an amorphous matrix of thick fibers. Their hitherto undescribed dark red pigment is neither phaeomelanin nor eumelanin, but seems to be related to melanins. Melanophores of at least one of these species, Agalychnis dacnicolor, exhibit color change in direct response to illumination, and it is suggested that these chromatophores are innervated.
33 citations
29 citations
25 citations
TL;DR: In this paper, a discrete maximum principle similar to the one derived by Pearson and Sridhar [1] is derived for a subclass of these problems, that is, systems with linear dynamics, convex inequality constraints, and convex performance index.
Abstract: Necessary and sufficient conditions for the optimization of multivariable discrete systems containing pure delays in dynamics, in performance index, and in constraints are investigated. Using nonlinear programming, it is shown that a discrete maximum principle similar to the one derived by Pearson and Sridhar [1] is valid for a subclass of these problems, that is, systems with linear dynamics, convex inequality constraints, and convex performance index.
19 citations
TL;DR: In this paper, the results of petrological and volcanological investigations of the Assab area (Ethiopia) are reported, and the central activity represented by a cumulus dome and two explosive craters are recognized.
Abstract: The results of petrological and volcanological investigations of the Assab area (Ethiopia) are reported. Fissure activity — which produced basaltic lava flows and several spatter cones — and central activity — represented by a cumulus dome and two explosive craters — have been recognized.
18 citations
TL;DR: The results indicate that the high levels of the enzyme present in the fetus enable the neonate to digest γ-glutamyl peptides, and the physiologic significance of GGTP activity in the intestine is still conjectural.
Abstract: Extract: The enzymatic activity hydrolyzing γ-glutamyl-β-naphthylamide (γ-glutamyltranspeptidase, GGTP) was studied in the small intestine of human adults and fetuses. Surgical biopsies taken from the proximal jejunum approximately 10 cm from the ligament of Treitz served as the source of the enzyme for adult subjects. The entire small bowel was obtained from fetuses of different ages and divided into three thirds for enzymatic assay. All samples were frozen immediately and used within 1–4 months. It was shown that enzymatic activities stored at −20° are stable for that period.
17 citations
TL;DR: The isolated RB are able to respond to Poly(U) and are also active in the endogenous protein synthesis in a cell-free system, which contrasts with the in vivo situation, where they appear to be completely inactive in protein synthesis.
TL;DR: The hypothesis of an a receptor mediation of the tonic noradrenergic inhibition of CRF-ACTH secretion is supported, given the administration into the third ventricle of the brain of a systemically ineffective dose of phentolamine increased plasma corticosterone when examined 1 hr later.
TL;DR: The skeletal muscle myoglobin of the water buffalo has been purified by a rapid and simplified procedure and the amino acid composition of the myoglobin has been determined.
Abstract: 1. 1. The skeletal muscle myoglobin of the water buffalo ( Bos bubalus L.) has been purified by a rapid and simplified procedure. 2. 2. The amino acid composition of the myoglobin has been determined. 3. 3. The N -terminal amino acid is glycine. 4. 4. The results have been compared with other mammalian myoglobins, particularly that of the cow.
TL;DR: Evidence is presented indicating that under both normal and hypoxic conditions the production of circulating Ep involves the interaction of a renal erythropoietic factor (also termed erythrogenin) with a serum protein component.
Abstract: IT is well established that the kidney is the main site of the production and/or activation of erythropoietin (Ep)1,2. Gordon et al.3 have presented evidence indicating that under both normal and hypoxic conditions the production of circulating Ep involves the interaction of a renal erythropoietic factor (also termed erythrogenin) with a serum protein component. Erythrogenin can be extracted from the light mitochondrial fraction prepared from homogenates of mammalian kidneys.
TL;DR: In this article, an analytical model of oil whirl in non loaded journal bearings is presented to determine the influence of operating parameters such as rotor mass, speed, oil viscosity, shaft and bearing dimensions on the whirling characteristics.
TL;DR: Evidence is given in favor of a central noradrenergic system that inhibits ACTH secretion via a-receptorial stimulation and the neurovascular hypothesis of ACTH secretory cell regulation seems to be well founded.
Abstract: Publisher Summary This chapter discusses the role of central nervous system in the regulation of synthesis and release of corticotrophin (ACTH). The chapter gives evidence in favor of a central noradrenergic system that inhibits ACTH secretion via a-receptorial stimulation. In dogs, the injection into the third ventricle of catecholamine precursors, catecholamines and drugs that release or protect catecholamines from inactivation, inhibits stress-induced adrenocortical activation. In rats, drugs that decrease brain catecholamine levels provoke adrenocortical activation, also when injected directly into the third ventricle of systemically ineffective doses. Specific depletion of noradrenaline but not of dopamine is able to cause increase of plasma corticosterone. Experiments concerning long-term catecholamine depletion, suggest the presence of a small, defined, functional pool of noradrenaline responsible for the tonic inhibition of ACTH secretion. Although a corticotrophin-releasing factor (CRF) is not chemically identified and synthesized, the neurovascular hypothesis of ACTH secretory cell regulation seems to be well founded. A possible role of brain catecholamines in the regulation of ACTH secretion is considered by numerous investigators.
TL;DR: Nuclei isolated from the developing sea urchin embryo Paracentrotus lividus and incubated in the presence of [3H-methyl] S-adenosylmethionine methylate their own DNA produce 5-methylcytosine and thymine, which originate by enzymatic methylation of DNA cytosines.
TL;DR: In this article, a deterministic, continuous time, nonstationary, multiproduct inventory model is formulated to find the number of joint replenishments, the order quantities, and the times at which orders should be placed which minimize the total cost over a finite time horizon.
Abstract: A deterministic, continuous time, nonstationary, multiproduct inventory model is formulated to find the number of joint replenishments, the order quantities, and the times at which orders should be placed which minimize the total cost over a finite time horizon. Both backlogging and no backlogging are considered. Conditions are given for the determination of the optimal policy, and their necessity and sufficiency are discussed. The case in which the costs are quadratic is dealt in detail and numerical examples are given.
TL;DR: It is concluded that dbc‐AMP induces in vivo a stimulatory effect on erythropoiesis via increased production of Ep, via a renal mechanism possibly represented by elevated levels of the renal ERYthropoietic factor.
Abstract: Summary. Dibutyryl cyclic AMP (dbc-AMP) was injected into ex-hypoxic polycythaemic mice either alone or with anti-erythropoietin (anti-Ep) serum. Anti-Ep totally abolishes the wave of erythropoiesis evoked by dbc-AMP. These results might indicate either that the action of this agent is totally Ep-dependent, or that a residual amount of endogenous Ep is necessary to allow dbc-AMP to exert a direct effect at the marrow level. The latter mechanism, however, is precluded by experiments indicating that administration of moderate amounts of anti-Ep, although abolishing totally the erythroid response to dbc-AMP, do not induce complete suppression of endogenous Ep activity and erythropoiesis. Furthermore, a significant rise of Ep plasma levels is observed in rats receiving dbc-AMP. Since this agent does not apparently modify the kinetics of endogenous Ep, it is postulated that dbc-AMP induces a rise in Ep production. This phenomenon, although unmodified in ureter-ligated animals, is completely abolished by bilateral nephrectomy. It is therefore concluded that dbc-AMP induces in vivo a stimulatory effect on erythropoiesis via increased production of Ep, via a renal mechanism possibly represented by elevated levels of the renal erythropoietic factor.
TL;DR: The absolute configuration of the dissymmetric olefin endo-dicyclopentadiene was determined in this article through the determination of the crystal and molecular structure of (+) (endo-dicycle) platinum dichloride.
Journal Article•
TL;DR: In this article, it was shown that the mechanical behavior of polyphenylene oxide composites is correlated in a simple fashion to the mechanical responses of the individual constituents, and that experimental values of yield stress, deformation during creep and time-to-yield can be superposed to form master curves.
Abstract: The mechanical behavior of particulate reinforced polyphenylene oxide composites is correlated in a simple fashion to the mechanical responses of the individual constituents. By use of time-temperature-composition superposition principles it is shown that experimental values of yield stress, deformation during creep and time-to-yield can be superposed to form master curves and that the shift factors are separable function of temperature, stress and composition. Yield stress data are shown to conform to an equation of the form σ y = K 1+ K 2 In while creep data fit a curve of the form ∊creep = A 0 exp – [(Q/RT)] [exp (σ/σc)] t 2. The temperature shift factor for the data was given by In aT = (20,150/T) – 65.5 and was independent of stress and composition. The yield stress of the composite σ yc was related to the yield stress of the matrix σ yo by σ yc = σ yo (1 − 1.21φ 0.67). Finally, the creep data for the composites could be superposed to a single curve by using a stress parameter σ c = σ co (1 ...
TL;DR: At a dose of 100 mg/kg/die/4 days i.m. of the various β-stimulant drugs, a significant increase in the levels of S-LDH was observed in the rats.
Abstract: 1.
The rats given isoprenaline (1–10–100 mg/kg/die/4 days i.m.) showed myocardial infarctions on histological examination as well as increase in the levels of S-GOT, S-GPT and S-LDH.
2.
The rats treated with various adrenergic β-stimulant drugs (terbutaline, salbutamol, soterenol, isoxsuprine, chlorprenaline, metaproterenol, ISOTIOD and quinterenol; 1–10–100 mg/kg/die/4 days i.m.) neither exhibited any significant cardiac histological changes (except infiltrations by histiocytes lymphocytes and monocytes with quinterenol and Th 1165a at 100 mg/kg/die/4 days i.m.) nor any changes in the levels of S-GOT and S-GPT.
3.
At a dose of 100 mg/kg/die/4 days i.m. of the various β-stimulant drugs, a significant increase in the levels of S-LDH was observed in the rats.
TL;DR: The data obtained show changes of the rate of synthesis of membranes in C. crescentus during the first synchronized division cycle: the rate is faster in the first 70 min and it drops by 26% during the following 40 min.
Abstract: The growth and division of cell membranes in Caulobacter crescentus has been studied. This microorganism divides into flagellated and stalked cells which are easily separated by centrifugation. The biosynthesis and partition of membranes was studied by labeling the proteins with [3H]-leucine and the lipids with [32P]. The membranes were prepared from cell spheroplasts. They further purified on a sucrose gradient. The data obtained show changes of the rate of synthesis of membranes in C. crescentus during the first synchronized division cycle (110 min): the rate is faster in the first 70 min and it drops by 26% during the following 40 min. During the period of faster synthesis the flagellated cells are changing into stalked cells while doubling in size. There is also an intracellular pool of membrane precursors the quantity of which almost doubles as the rate of membrane synthesis decreases, i.e., before cell division. The macromolecules constituting the membranes are not degraded. After division, in each membrane of the two morphologically different cell types the specific radioactivity is 50% of that of the parent cell membranes.
TL;DR: In this paper, a model for the central stars of planetary nebulae before and after the ejection of mass has been proposed, but none of them seems to be in good agreement with observations.
Abstract: THEORETICAL models for the central stars of planetary nebulae before and after the ejection of mass have appeared in the literature recently1,2, but none of them seems to be in good agreement with observations. Stars of mass below the Chandrasekhar limit consisting chiefly of carbon and oxygen (but not burning carbon) seem to be in fair agreement with observed data only if “reddened” with an ad hoc thin hydrogen envelope and the rapid evolution implied by the observations (∼ 105 yr) is attributed to speeding up of the cooling due to neutrino processes. A composition of carbon and heavier elements for these stars is also suggested by other authors3.
TL;DR: In this paper, it was shown that, in complementary n+p and p+n abrupt junctions for pure electron or hole multiplication, four different multiplication factors and two breakdown voltages can be defined.
Abstract: It is shown that, in complementary n+p and p+n abrupt junctions for pure electron or hole multiplication, four different multiplication factors and two breakdown voltages can be defined. As an example, the four multiplication curves for a doping of 1016 cm−3, and the breakdown voltages of p+ n and n+ p abrupt Si junctions, are reported, using the multiplication data of Lee et al. and Van Overstraeten and De Man.
TL;DR: Fractional encephalography following hyperventilation was well tolerated in all the patients and the great incidence of good filling of both the ventricular system and the subarachnoid spaces reduces the number of patients requiring ventriculography.
Abstract: Artificial hyperventilation was used during fractional encephalography. In 9 patients who underwent conventional fractional encephalography, the hyperventilation was started at the end of the investigation. In the remaining cases, in which fractional encephalography by the conventional technique gave unsatisfactory results, the examination was repeated 5 days later after mechanical hyperventilation for 30 min under intermittent positive pressure. In 3 patients with expanding processes of the posterior cranial fossa, hyperventilation encephalography confirmed the failure of passage of air into the ventricular system, and in 12 patients either visualisation or improved filling of the ventricular system and subarachnoid spaces was obtained. The great incidence of good filling of both the ventricular system and the subarachnoid spaces reduces the number of patients requiring ventriculography. Fractional encephalography following hyperventilation was well tolerated in all the patients.
TL;DR: Intravenous infusion of prostaglandin A1 at hypotensive dosage into reserpinized dogs increased plasma glucose and FFA levels and lowered the rate of glucose disappearance following glucose.
Abstract: Intravenous infusion of prostaglandin A1 at hypotensive dosage into reserpinized dogs increased plasma glucose and FFA levels and lowered the rate of glucose disappearance following glucose