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Showing papers by "University of Naples Federico II published in 1976"



Journal ArticleDOI
TL;DR: It has been found that there exists a complex interaction between the environmental factors and the “endogenous hormonal trigger” that subsequently steps into the regulation of spermatogenesis.
Abstract: The process of spermatogenesis in Rana esculenta (living in the surroundings of Naples) resurges gradually in the spring months, proceeds actively through the summer and declines gradually in the winter months reaching an almost total “quiescence” for a short length of time. The repeating from year to year with a distinct regularity of spermatogenetic cycle suggests that environmental cues play a role in timing its various phases. Both temperature and photoperiod appear to be potential modifiers of spermatogenetic activity in this species. It is, however, probable that photoperiod acts only in a permissive way to facilitate the temperature response which seems to be the more direct modifier of the testicular activity. The proliferation of primary spermatogonia seems to be favoured by only low temperatures. The formation of secondary spermatogonia, and primary and secondary spermatocytes occurs when there occurs a gradual increase in the ambient temperature, day length and gonadotropin secretion. This period is characterized by very low plasma level of testosterone, that, through the reduced negative feedback to the hypothalamus, favours an increased secretion of FSH-like gonadotropin. Spermatid formation is entirely androgen-dependent as confirmed by the use of a specific antiandrogen, cyproterone acetate. In fact spermatid formation naturally occurs in a period when plasma level of testosterone is increasing and pituitary gonadotrops are declining in their secretory activity. In this period the ambient temperature and the photoperiod gradually decline. The importance of lateral eyes and the pineal gland in the mediation of influence of photic cues has been shown. It seems that without either the eyes or the pineal gland both light and temperature are completely ineffective in stimulating the early spermatogenesis, which shows the permissive role of light on temperature influence upon spermatogenesis. Hypophysectomy impairs spermatogenesis, which can be restored by a replacement therapy with homoplastic pituitary extract. Testosterone alone does not restore spermatogenesis except enhancing spermatid formation. Pituitary extract stimulates mitotic activity of spermatogonia and formation of primary and secondary spermatocytes. Testosterone is not involved because the stimulatory effects of pituitary extract are only marginally blocked by the antiandrogen. In fact spermatogonial multiplication is partially inhibited, while spermatid formation is totally blocked, indicating that ICSH-like gonadotropin acts upon the formation of spermatids through the stimulation of testosterone production. Thus it has been found that there exists a complex interaction between the environmental factors and the “endogenous hormonal trigger” that subsequently steps into the regulation of spermatogenesis.

137 citations


Journal ArticleDOI
TL;DR: A radioreceptor assay of Epidermal Growth Factor (EGF), which uses as binder plasma membranes prepared from target tissues, instead of specific antibodies, is described, suggesting that the tissues under investigation can be classified in two groups: a - “target tissues” and b- “synthetizing” tissues, which release the factor under pilocarpine stimulation.

63 citations


Journal ArticleDOI
TL;DR: In this paper, the so-called stress-optical law is checked with the aid of flow birefringence technique, which is used for the analysis of polymer melts.
Abstract: Transient stresses including normal stresses, which are developed in a polymer melt by a suddenly imposed constant rate of shear, are investigated by mechanical measurement and, indirectly, with the aid of the flow birefringence technique. For the latter purpose use is made of the so-called stress-optical law, which is carefully checked.

49 citations


Journal ArticleDOI
TL;DR: Polyamines of Caldariella acidophila have been detected by H.V. electrophoresis and gas-liquid chromatography combined with mass spectrometry and the possible metabolic interrelations of such molecules are discussed.

48 citations


Journal ArticleDOI
01 Feb 1976-Blood
TL;DR: Since the liver plays a prominent role in extrarenal Ep production, Kupffer cells may represent a major source for Ep in the anephric rat, and it is tentatively concluded that the RES is a source of extrarennal Ep.

46 citations


Journal ArticleDOI
TL;DR: In this article, a modified cone-and-plate apparatus was designed for the measurement of the flow birefringence of polymer melts in a wide range of shear rates.
Abstract: A description is given of a modified cone-and-plate apparatus designed for the measurement of the flow birefringence of polymer melts in a wide range of shear rates. Results are given of measurements on samples of high and low density polyethylene and polystyrene. Anomalies, as found in the extinction angle curves near the fringes, where the phase differences become equal to multiples of 2π, point to pronounced edge effects which appear to depend on the type of polymer. The measurements on the high density polyethylene were used to check the validity of the stress-optical law. The measurements on the low density polyethylene sample show mechanical degradation of this polymer. Some typical transient measurements on the polystyrene sample are presented and successfully related to the corresponding mechanical measurements, as obtained with the aid of a cone-and-plate Weissenberg rheogoniometer.

36 citations


Journal ArticleDOI
TL;DR: The results indicate that changes of pressure in the first order peritubular capillaries of superficial nephrons are merely secondary to changes in glomerular capillary pressure.

35 citations


Journal ArticleDOI
TL;DR: It was possible to exclude a sympathetic mediation or a direct stimulation of pancreatic beta-receptors as a likely mechanism of PGE1 action.
Abstract: The effect of PGE 1 and PGA 1 intravenous infusion (2/μg/min) on plasma glucose and glucagon levels was investigated in normal, sympathectomized and propranolol-treated rats. PGE 1 infusion significantly increased glucose and glucagon levels, while PGA 1 had no effect. Since the dose of PGE 1 used in this study was able to reduce the arterial blood pressure by about 20%, the possibility that PGE 1 acted indirectly through a reflex sympathetic overactivity was tested. The increases in plasma glucagon induced by PGE 1 occurred also in sympathectomized or in beta-blocked animals. Thus, it was possible to exclude a sympathetic mediation or a direct stimulation of pancreatic beta-receptors as a likely mechanism of PGE 1 action.

35 citations


Journal ArticleDOI
TL;DR: In this article, the application of modern non-linear continuum thermodynamics to the analysis of energy dissipation in both isothermal and non-isothermal flow of polymers is discussed.
Abstract: The application of modern non-linear continuum thermodynamics to the analysis of energy dissipation in both isothermal and non-isothermal flow of polymers is discussed. A fundamental simplification of the field equation for the balance of energy arises if the assumption is made that the flowing polymer is a material with entropic elasticity. This assumption is partly justified by structural arguments, and its validity can be checked experimentally. The results of the experiments performed support the validity of the assumption.

34 citations


Journal ArticleDOI
TL;DR: In the Campania area volcanic rocks belonging both to the trachytic (low K) and tephritic (high K) series occur, the high K series being well subordinate to the low K one.
Abstract: In the Campania area volcanic rocks belonging both to the trachytic (low K) and tephritic (high K) series occur, the high K series being well subordinate to the low K one. Volcanology of the trachytic series shows that: 1) the most widespread products are trachytes and alkali-trachytes, 2) in the stratigraphic sequences the most evolved (salic) volcanics are the oldest. The Roccamonfina trachytic series includes several Hy and Q normative lavas, whereas the majority of the Phlegraean Fields rock samples are Ne normative. In the A F M diagram, the lack of the Fe-rich phases gives a linear trend similar to the calc-alkaline series. An important feature of the Roccamonfina trachytic series is the coexistence of two clinopyroxenes of diopsidic and salitic composition observed in all the studied samples. The phenocrystic assemblage (clinopyroxenes, Mg-olivine, Mg-biotite) indicates that the crystallization of the melt probably occurred under relatively highpH2O conditions. The crystallization of the diopsidic pyroxene was controlled mainly by a relatively high silica activity of the magma, whereas the salitic pyroxene, which crystallized at a lithostatic pressure lower than the diopside, might be related to the increase of the alumina activity in the final trachytic liquid. The occurrence of two clinoproxenes suggests two main episodes of crystallization of the parental latitic magma, one at a depth of about 15 km producing diopside phenocrysts and the second at a shallower depth where salite was in equilibrium with the residual melt. The volcanic rocks of the Roccamonfina trachytic series (latites, trachytes and alkalitrachytes) have likely been generated by fractionation of a latitic melt, whereas the strongly porphyritic trachybasalts formed by crystal settling of pyroxenes and olivine from a more evolved latitic melt.

Journal ArticleDOI
TL;DR: The site through which behavioural, electrocortical and body temperature effects of prostaglandins E 2 and A 1 were mediated appears to be the hypothalamus.

Journal ArticleDOI
TL;DR: Study of the germinal epithelium in the adult lizard shows that the germ cells constitute clusters of synchronized cells interconnected by intercellular bridges, which interconnect oogonia as well as early meiotic prophase oocytes (zygo-pachitene).

Journal ArticleDOI
TL;DR: It is suggested that the higher metabolic activity of the inner layer may provide a means of metabolising some of the excess lactate produced by the myotomal muscles.
Abstract: 1. 1. The inner and outer myocardial layers of ventricles from adult tuna fish were studied using biochemical and ultrastructural methods. 2. 2. Electron transport particle preparations prepared from the inner layer were found to have higher respiratory enzyme activities than the outer layer. 3. 3. No difference was observed between the myofibrillar ATPase activity or the LDH isoenzyme of the two layers. 4. 4. The mitochondria of the inner layer were found to have a higher cristae density than those from the outer layer. 5. 5. It is suggested that the higher metabolic activity of the inner layer may provide a means of metabolising some of the excess lactate produced by the myotomal muscles.

Journal ArticleDOI
TL;DR: The correlation between hyperplasia of hepatic RES and enhanced Ep production in anephric rats primed with these agents suggests that Kupffer cells constitute a major source for extrarenal Ep.
Abstract: Erythropoietin (Ep) levels were assayed in serum of adult male rats subjected sequentially to (1) administration of colloidal carbon, Zymosan or their vehicles (2) sham operation or bilateral nephrectomy with and without subtotal hepatictomy, and (3) hypoxia (0.45-0.40 atmospheres of air for 6 h starting 1 h after the operation). In anephric rats these agents induced a significant potentiation of hypoxic Ep activity. Since they did not apparently modify the kinetics of exogenous Ep, it is postulated that this phenomenon is mediated by enhanced extrarenal Ep production. Both colloidal carbon and Zymosan induced hyperplasia of the reticuloendothelial system (RES). Moreover, subtotal hepatectomy almost abolished the Ep response to hypoxia evoked by Zymosan. The correlation between hyperplasia of hepatic RES and enhanced Ep production in anephric rats primed with these agents suggests that Kupffer cells constitute a major source for extrarenal Ep. Additionally, it is of interest that colloidal carbon and Zymosan did not significantly modify the renal production of Ep.

Journal ArticleDOI
TL;DR: The results of this work show that fusicoccin is a vivotoxin sensu Dimond & Waggoner, and the physical and biological properties of the purified toxin were found to be identical to those of authentic fusoform.
Abstract: Green peaches were artificially inoculated with Fusicoccum amygdali Del. and the infected tissues extracted with chloroform. To isolate the phytotoxic substance, extracts were purified on chromatographic columns. About 5 mg pure toxin were obtained from 1 kg infected peach pulp. A similar procedure yielded about 10 mg toxin per kg of tissues from naturally infected almond shoots with cankers of F. amygdali. The physical and biological properties of the purified toxin were found to be identical to those of authentic fusicoccin. The results of this work show that fusicoccin is a vivotoxin sensu Dimond & Waggoner.

Journal ArticleDOI
TL;DR: The presence of two phaeomelanic pigments, trichochrome B and C, was demonstrated in the urine of a patient with malignant melanoma metastases.
Abstract: The presence of two phaeomelanic pigments, trichochrome B and C, was demonstrated in the urine of a patient with malignant melanoma metastases.

Journal ArticleDOI
TL;DR: Experiments performed with disrupted non-phosphorylating mitochondria demonstrate that this difference in temperature dependence of the two cardiac compartments depends on the integrity of the mitochondrial membranes.
Abstract: 1. The oxidative phosphorylation and the temperature dependence of mitochondria prepared from the outer compact layer and the inner spongy layer of adult tuna heart ventricle have been examined. 2. Mitochondria of the inner layer show higher succinoxidase and NADH-oxidase activities as compared with those of the outer layer. 3. Arrhenius plots for succinate oxidation by phosphorylating mitochondria show that the temperature dependence of the inner layer is higher than that of the outer layer. 4. Experiments performed with disrupted non-phosphorylating mitochondria demonstrate that this difference in temperature dependence of the two cardiac compartments depends on the integrity of the mitochondrial membranes. 5. These findings are discussed in relation to the physiology of the fish.

Journal ArticleDOI
TL;DR: The nuclear DNA content was studied histophotometrically in 49 reptilian species to indicate that species of three orders show DNA values falling within similar variability range.
Abstract: The nuclear DNA content was studied histophotometrically in 49 reptilian species. The results obtained indicate that species of three orders show DNA values falling within similar variability range.

Journal ArticleDOI
TL;DR: The data on the epidemiologic situation of sarcoidosis from 24 countries of Europe have been reviewed and the new facts seem to demonstrate that the differences between the frequency of this disease in the north and south are not real.
Abstract: The data on the epidemiologic situation of sarcoidosis from 24 countries of Europe have been reviewed. The new facts seem to demonstrate that the differences between the frequency of this disease in the north and south are not real. The actual situation is dependent on the general knowledge of this disease and on the extent and intensity of the active detection of its asymptomatic stage. A new prospective cooperative study of the yearly incidence of all forms of sarcoidosis in the total population of at least some European countries would be desirable.

Journal ArticleDOI
01 Jan 1976
TL;DR: The data obtained through a series of simulated dialysis show that carbon adsorbs, besides creatinine and other compounds, urea in satisfactory quantities, make the routine use of an artificial kidney based on a cold operating carbon depurator extremely practical.
Abstract: A prototype of artificial kidney with regeneration of the dialysis fluid in active carbon at low temperature is presented. The data obtained through a series of simulated dialysis show that carbon adsorbs, besides creatinine and other compounds, urea in satisfactory quantities. Furthermore, the possibility of completely regenerating carbon with tap water washing makes the routine use of an artificial kidney based on a cold operating carbon depurator extremely practical.

Journal ArticleDOI
TL;DR: The human placenta arginase is a metalloenzyme with an optimum pH of 9.1; L-Ornithine and L-lysine show competitive inhibition with Ki values of 6.3 and 14 mM respectively.
Abstract: Arginase was purified about 1800-fold from extracts of human full-term placenta; the enzyme appeared to be homogenous by disc electrophoresis and molecular-sieve chromatography. The mol. wt. determination by gel filtration and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis yielded a value of 70000 for the most pure and the partially purified enzyme. The human placenta arginase is a metalloenzyme with an optimum pH of 9.1. The Km for L-arginine is 27 mM. L-Ornithine and L-lysine show competitive inhibition with Ki values of 6.3 and 14 mM respectively.

Journal ArticleDOI
TL;DR: In the Iblean region, southeast Sicily, a sequence of subaqueous and subaerial volcanics is interlayered in sedimentary levels, Upper Miocene to Lower Pleistocene in age as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this paper, the authors made electromagnetic soundings using two techniques in an area around the summit of Kilauea Volcano, Hawaii, where the target for the soundings was a conductive zone at a depth of about one kilometer, associated with geothermal heating.
Abstract: Electromagnetic soundings were made using two techniques in an area around the summit of Kilauea Volcano, Hawaii. The target for the soundings was a conductive zone at a depth of about one kilometer, associated with geothermal heating. In one sounding method, an electromagnetic field was generated by passing current steps through a grounded-wire transmitter, while in the other, an electromagnetic field was generated by passing current steps through an ungrounded loop. The field was detected at a receiving site by measuring the vertical component of magnetic induction using an ungrounded loop. Both methods accurately reflected the presence of conductive rocks at depth. However, the use of a grounded-wire source had a strong advantage in that the field decayed with distance more slowly than that from the loop source, and a larger area could be surveyed using a single grounded-wire source.

Journal ArticleDOI
TL;DR: The results seem to suggest that the disappearance of adrenocortical activation following long-term treatment with reserpine is due to the stimulated formation of a small functional pool of NE available for the tonic inhibition of CRF-ACTH secretion.
Abstract: Daily i.p. injection of reserpine for 9 days strongly depletes hypothalamic norepinephrine (NE); after an initial activation, adrenocortical function returns to control values by the 5th day. Tyrosine

Journal ArticleDOI
TL;DR: The two main peaks of activity, designated form I and form II, differ in the following features: 1) form I is able to use poly(dA) as primer-template more efficiently than form II.


Journal ArticleDOI
TL;DR: A controlled non-blind multicenter trial was conducted in 211 acne patients to test the activity of topical retinoic acid against sulfur-resorcinol—salicylic acid and placebo, which proved to be superior to the standard and to the placebo.
Abstract: A controlled non-blind multicenter trial was conducted in 211 acne patients to test the activity of topical retinoic acid against sulfur-resorcinol--salicylic acid and placebo. Uniform evaluation criteria were used. After 8 weeks' treatment in comparable groups of patients, retinoic acid proved to be superior to the standard and to the placebo. The difference was statistically significant. Side effects were present in a number of patients treated with the active substances and with the placebo (mainly erythema), but rarely was the treatment discontinued.

Journal ArticleDOI
TL;DR: Single radial diffusion combined with the Rose Bengal test permitted rapid identification of all of the Brucella abortus-infected cattle in a study group of 689 animals.
Abstract: Single radial diffusion combined with the Rose Bengal test permitted rapid identification of all of the Brucella abortus-infected cattle in a study group of 689 animals.

Journal ArticleDOI
TL;DR: In young chicks intrahypothalamic infusion of cholera toxin produced a dramatic and dose-dependent increase in motor activity and similar effects were also obtained in adult fowls after injection into the third cerebral ventricle, the hypothalamus or the paleostriatum augmentatum.