Showing papers by "University of Turin published in 1969"

Experimental evidence for the existence of an extrarhinencephalic control of the activity of the cobalt rhinencephalic epileptogenic focus. Part 2. Effects of the paleocerebellar stimulation.

Abstract: SUMMARY In chronic unanaesthetized unrestrained cats, with cobalt-induced amygdaloid or hippocampal epileptogenic focus, the relationship between the focus and caudate nucleus activity was studied. The results obtained justify the following considerations. 1 The stimulation both of the caudate nucleus and the internal capsule was shown to have an excitatory effect upon the cobalt rhinencephalic focus. The threshold stimulation capable of eliciting a hippocampal or amygdaloid seizure discharge was clearly lower for the internal capsule than for the caudate nucleus. It has been thought, therefore, that the source of the excitatory influence was the internal capsule and that, consequently, the effects of the caudate stimulation were due to a capsular fibre excitation by current spread. 2 The spread to the caudate nucleus of the interictal and ictal activity of the cobalt amygdaloid or hippocampal focus, was accompanied by the appearance of high-voltage slow caudate activity. Since this activity was provoked also by the direct caudate stimulation, it appeared likely that this is the non-specific and monotonous bioelectric expression of the reaction of the caudate nucleus to stimuli of a certain intensity reaching it. 3 The fact that, during the high-voltage slow caudate activity, there was a clear decrease in the cobalt amygdaloid or hippocampal focus excitability, seems to indicate an inhibitory influence of the slow caudate activity on the rhinencephalic focus. In the light of these facts some speculations are put forward on the probable existence and significance of an inhibitory feed-back system related to the caudate nucleus and controlling the cobalt rhinencephalic focus activity. RESUME Chez des chats chroniques, non anestheAsieAs et libres, porteurs d'un foyer eApileptogene amygdalien ou hippocampique, induit par le cobalt, on a eAtudieA la relation existant entre l'activiteA du foyer et celleA du noyau caudeA. Les reAsultats obtenus ont permis d'en tirer les consideArations suivantes: 1 La stimulation du noyau caudeA et de la capsule interne a un effet activant sur le foyer rhinenceAphalique. Le seuil de stimulation capable de provoquer une deAcharge critique hippocampique ou amygdalienne est nettement plus bas pour la capsule interne que pour le noyau caudeA. On en a deAduit que l'origine de l'effet activant eAtait dans la capsule interne et que, par conseAquent, les effets de la stimulation du noyau caudeA eAtait dus aG l'excitation des fibres capsulaires par diffusion du courant. 2 La diffusion au noyau caudeA de l';activiteA intercritique et critique du foyer amygdalien et hippocampique s'accompagnait de l'apparition d'une activiteA lente de grande amplitude dans le caudeA. Puisque cette activiteA etait aussi provoqueAe par la stimulation directe du caudeA, il a semble qu'elle eAtait l'expression bioelectrique non speAcifique et monotone de la reAaction du noyau caudeA aux stimuli d'une certaine intensiteA qui l'atteignent. 3 Le fait que, pendant l'activiteA lente et de grande amplitude du noyau caudeA, il y avait une diminution de l'excitabiliteA du foyer amygdalien ou hippocampique, semble indiquer que l'activiteA lente du caudeA exerce une influence inhibitrice sur le foyer rhinencephalique. A la lueur de ces faits des hypotheGses sont avancees sur l'existence probable et la signification d'un systeGme de feedback inhibiteur en relation avec le noyau caudeA et controlant l'activiteA du foyer rhinenceAphalique produit par le cobalt.

Once-a-day neurally stimulated and basal ACTH secretion phases in man and their response to corticoid inhibition.

Abstract: The sensitivity of the ACTHsecreting system to corticoid inhibition was studied in normal subjects by measuring variations in excretion of urinary 17-OHCS induced by intravenous infusion of corticoids in different periods of the day (4–8 am; 4 am–4 pm; 8 am–4 pm; 4–8 pm; 8 pm–midnight; midnight–4 am). Submaximal infusion doses (660 μg/hr 6-methylprednisolone; 30 μg/hr dexamethasone) led to partial inhibition only in the nocturnal early morning hours and no inhibition in the period from 8 am to midnight; only massive doses of dexamethasone (200 μg/hr) produced inhibition in this latter period. The following hypothesis is put forward: The ACTH-secreting system has 2 daily activity phases with different control mechanisms. One in the nocturnal early morning hours is the result of neural activity directed to the hypothalamus, superimposed on the basal activity and responsible for the circadian rhythm. This once-a-day impulse would appear to be linked to the rapid eye movement sleep stages. Corticoid-...

Proliferative potential of out-of-cycle leukaemic cells.

Abstract: THE proliferative activity of an acute leukaemic blast cell population will depend on the respective sizes of its proliferating and non-proliferating compartments. Proliferating blasts have no self-maintaining kinetic pattern1, but after one or two divisions become much smaller and enter the non-proliferating compartment2–4. An important question raised by this new evidence is, what is the fate of these small, non-proliferating blasts ? Are they end cells, destined to die as such, or are they only apparently mature, retaining a latent potential for division ? The experiment reported here was done to test whether the small blasts forming part of the non-proliferating compartment retained the potential to proliferate.

Interest Rate Policy and External Balance

Abstract: Introduction, 242. — I. The pure stock adjustment model, 244. — II. The effects of portfolio growth, 246. — III. An empirical application: U.S. short term capital movements, 249. — IV. Interest costs, 252. — V. The interrelationships between interest rates, portfolio size, and capital and interest flows, 257. — VI. Summary and conclusions, 259.

Immunofluorescent localisation of calcitonin in medullary C-cell thyroid carcinoma, using antibody to the pure porcine hormone.

Abstract: In spite of considerable differences in the amino-acid sequences of human and porcine calcitonin, cross reactivity is demonstrable, by indirect immunofluorescence, between human C cells and porcine antibody In a medullary carcinoma of the thyroid, removed from a 19-year old female, about 40% of the tumour cells contained calcitonin The hormone was present not only in the cytoplasm but also, in many instances, in the nucleoli This latter finding has not been observed by us, or reported by others, in normal C cells from any animal species

Choline acetyltransferase (ChAc) activity in developing chick optic centres and the effects of monolateral removal of retina at an early embryonic stage and at hatching.

Abstract: — The choline acetyltransferase (ChAc) activity was measured in the optic centres of chick embryos after early removal of the optic cup and of young chicks after monolateral extirpation of the right eyeball after hatching. The contralateral optic lobes were thus deprived of their complement of retinal fibres. The following results were obtained: in chick embryos the ChAc was slightly lower in the deafferented lobe between the 10th and the 14th day of incubation; between the 14th and the 17th day a critical fall in activity was observed leading to a significant ChAc loss of 71 per cent. In eye deprived chicks no significant change in total ChAc activity occurred during the first postoperative month; significant changes were found only in the second month. The results reached so far suggest that removal of retinal fibres does not cause short term changes in optic centre ChAc in either the embryo or the chick. ChAc contained in nerve cell bodies seems independent of synapses and its behaviour is interpreted as a reflection of metabolic disturbance of the centre.

Momentum dependence of diffraction slopes in meson--nucleon scattering.

Abstract: The slopes $B(k)$ of the exponential forward peak for ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}p$ and ${K}^{\ifmmode\pm\else\textpm\fi{}}p$ elastic scattering have been surveyed in the region $0.3\ensuremath{\lesssim}{P}_{\mathrm{lab}}\ensuremath{\lesssim}20.0$ GeV/c. Plots of the momentum dependence of $B(k)$ reveal striking enhancements at momenta corresponding to the location of known high-spin, high-elasticity resonances. There are indications that the background behavior of $B(k)$, when considered over such a wide momentum interval, might be smoothly rising in all cases; thus, the forward peak associated with background diffraction effects would appear to shrink not only in ${K}^{+}p\ensuremath{\rightarrow}{K}^{+}p$ interactions, where resonance formation is weak (or absent), but also in ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}p$ and ${K}^{\ensuremath{-}}p\ensuremath{\rightarrow}{K}^{\ensuremath{-}}p$ interactions, where many prominent resonant states are formed. An explanation for the behavior of $B(k)$ is presented, based on the properties of the logarithmic derivative of the differential cross section in the forward direction. As a quantitative illustration, $B{(k)}_{{K}^{\ensuremath{-}}}$ was derived in terms of a simple phenomenological model, which involves a linear superposition of diffractive-like and resonant amplitudes. In this way a fit to the $B{(k)}_{{K}^{\ensuremath{-}}}$ and ${K}^{\ensuremath{-}}p$ total-cross-section data could be obtained throughout the entire momentum region. The information which can be derived from the experimental study of $B(k)$ is discussed; this has bearing on the determination of resonance properties and on the behavior of the spin-flip amplitude.

Dark reticular cells in human lymphadenitis and lymphomas.

Abstract: Forty human lymph nodes (16 cases of Hodgkin’s disease, 9 cases of lymphosarcoma, 5 cases of reticulum cell sarcoma, 4 cases of chronic lymphoid leukemia, and 6 cases of lymphadenitis) were studied by light and electron microscopy. In 5 cases the specimens were fixed in OsO4, in the other 35 cases the tissues were fixed in aldehydes and then in 0OsO4. Peculiar dark cells were found in all aldehyde-fixed neoplastic and non-neoplastic lymph nodes, and could be seen in light microscopy on semi-thin sections and appeared fusiform or irregularly star-shaped. In electron microscopy the dark cells often showed thin and variously branched cytoplasmic processes. They appeared sometimes to be related to collagen fibres, and some of them showed phagocytic activity. Nuclear and/or cytoplasmic degenerative changes could be observed in several dark cells. The findings are discussed; the hypothesis is suggested, that the dark cells are a particular functional state of reticular cells with frequent degenerative changes.

A histochemical study on the distribution and localization of beta-glucuronidase activity in cerebral tumors.

Abstract: Beta-glucuronidase activity has been studied in 46 cerebral tumors by Naphthol AS-BI beta-D-glucuronide and diazotized pararosanilin. The distribution pattern of the enzyme activity is similar to that already observed for other lysosomal enzymes, with some minor differences. The histochemical staining increases in regressive or catabolic areas so that its relationship with malignancy appears to be indirect. Special regard is devoided to some cytotypes, such as giant cells of glioblastoma and gemistocytic astrocytes whose high enzyme activity is considered as a sign of cellular regression.

Nuclear Sheets in Epithelial and Connective Tissue Cells

Abstract: THIN sheets of nuclear material limited on both sides by the nuclear envelope have been described in several electron microscope studies and referred to as nuclear blebs, pockets, loops or projections. The first term (nuclear sheets) seems to be the most apt to describe all the morphological features of these structures on thin sections1. They have chiefly been recorded in association with interphase nuclei of human and other mammals (see refs. 2–6), but they have also been studied in amphibia7, a bird5 and a cyclostome5. The remarkable feature of the nuclear sheets is their approximately constant thickness, about 300 and 500 A7. The middle osmiophilic layer2 can be related to the strongly osmiophilic material8 or to the “line C”4 described by others: all these structures have to be referred to the thread-like structural unit or unit thread of heterochromatin forming either envelope-limited sheets or envelope-associated layers6. Structural explanations for the formation of the nuclear sheets have been suggested4,9, but so far their function is unknown, even though it seems likely to be related to the extension of the contact surface between nucleus and cytoplasm.

In vitro study of C (parafollicular) cells of dog thyroid in organ culture.

Abstract: Le cellule C (parafollicolari) della tiroide di cane conservano in vitro, in coltura organotipica, i loro caratteri istochimici ed ultrastrutturali. Tali cellule, cui viene attualmente attribuita la funzione di produrre calcitonina, reagiscono ad una elevazione del contenuto in calcio del terreno di coltura, con modificazioni istochimiche (perdita della argirofilia e metacromasia) e ultra-strutturali (diminuzione fino a scomparsa dei granuli di secrezione). Questi studii fanno ritenere possibile che la secrezione di calcitonina venga direttamente regolata dal livello del calcio.

Free radical polymerization of unconjugated dienes. VIII. Divinilether in benzene at 70°C.

Abstract: By the application of some kinetic relationships between the monomer concentration and the composition of the polymers, in terms of monomeric andstructural units, to the products of the free radical polymerization at 70°C of divinylether in benzene, it was possible to evaluate the strong tendency of this monomer to give high fractions of monocyclic and bicyclic structural units. Furthermore evidence was given that the residual unsaturations in the polymers belong to monocyclic units, and are not directly pendant from the polymer backbone. Einige kinetische Beziehungen zwischen Monomerkonzentration und Struktur der Monomerbausteine werden auf Polymere aus Divinylather angewendet, die durch radikalische Polymerisation in Benzol bei 70°C erhalten wurden. Divinylather hat eine grose Neigung monocyclische und bicyclische Struktureinheiten im Polymeren zu bilden. Es wird zu zeigen versucht, das die ungesattigten Gruppen im Polymeren an monocyclische Struktureinheiten gebunden sind und nicht an lineare Einheiten der Hauptkette.

Clonal Compartmentation in the Antibody-Producing Lymph Node

Abstract: The antibody synthesizing cell is specifically differentiated toward the production of an immunoglobulin belonging to a single class, exhibiting only one allelic allotypic specificity for each locus and probably possessing a single antibody activity [1, 2, 3, 4]. The antigenic stimulus is known to induce a complex set of events, including proliferation of immunocompetent cells [5, 6, 7, 8], in lymphopoietic tissue. If the specific differentiation is preserved through cell generations, the immunopoietic tissue should be constituted by more or less delimited clusters of cells sharing a common pattern of differentiation.