Showing papers by "University of Siena published in 1972"

Insect Sperm Cells

Abstract: Publisher Summary The spermatozoon of insects has evolved in the direction of increased motility—its shape, structure, metabolism, and locomotory capabilities are tremendously differentiated. In many instances they attain an extreme specialization which is related to: (1) the mode of sperm transmission (internal fertilization always being the case); (2) the duration of its survival in the male genital tract or within spermatophores and spermathecas; (3) the type of fluid they have to swim in; and (4) the complexity of the egg envelopes they must penetrate. Typical features of the insect spermatozoon are the following: a generally very slim shape with an extremely elongated head; a bi- or three-layered acrosomal complex; an exceedingly long tail whose axial filament is flanked by accessory structures usually derived from mitochondria1 transformations. Along these lines, evolutionary changes have resulted in a highly diversified and, in some respects, puzzling picture.

The spermatozoon of Branchiostoma lanceolatum L

Abstract: Under the electron microscope, the spermatozoon of Branchiostoma lanceolatum shows a spherical nucleus deeply grooved along its caudal third, a bistratified acrosome enriched by plentiful subacrosomal material, two centrioles, mitochondria fused into a single mass surrounding the centriolar region which is highly asymmetrical, a 9 + 2 flagellum tilted with respect to the longitudinal symmetry axis of the nucleus. The sperm of Branchiostoma shares the overall features of that of the Tunicata and fits in perfectly with the phylogenetic position of the Leptocardia.

Initial increase of plasma radioactive calcium after intravenous injection of calcitonin in man.

Abstract: 1. An intravenous infusion of calcitonin produced a sudden increase of plasma radioactivity after intravenous administration of 47 Ca in man. 2. This effect was noted a few minutes before the well-known decrease of plasma calcium concentration. 3. A mathematical evaluation of this phenomenon demonstrated that: (a) it was significant in normal subjects, provided patients were given calcitonin 60–360 min after the intravenous injection of 47 Ca; (b) it was generally not significant in patients with senile osteoporosis or osteomalacia; (c) it was particularly evident in patients with generalized Paget9s disease or multiple myeloma. 4. Surface measurements performed on soft tissues and bone demonstrated a transient, simultaneous decrease of 47 Ca radioactivity from bone. 5. The increase in plasma radioactivity implies a shift of 47 Ca from reservoirs with high specific radioactivity, possibly bone cells, to the circulation. 6. According to these data two different mechanisms of action of calcitonin could be considered: an early effect on bone cells producing a shift of calcium to the circulation, and the well-known later hypocalcaemic effect through diminution of bone resorption.

Treatment of Parkinson's disease with L-DOPA and an association L-DOPA plus a DOPA decarboxylase inhibitor.

Abstract: l-DOPA therapy of Parkinsonism by mouth, today universally accepted, may induce undesirable effects which can sometimes be of a certain severity.

Clinical aspects of regional cerebral blood flow.

Abstract: Publisher Summary The studies on cerebral blood flow (CBF) reported in this chapter have been performed using the technique developed by Lassen and co-workers in 1963; the method requires the injection of a bolus of a radioactive inert gas solution ( 85 Kr or 133 Xe) into the internal carotid artery. Compartmental analysis of the curve is not the only approach used to calculate the regional blood flow. However, it offers the advantage of giving the clearance rate and relative weight of the two components of the curve that have been assumed to represent two separate tissue compartments; the gray and white matter of the brain. In clinical studies, analysis of the compartmental data has not been thoroughly exploited. A second type of compartmental analysis may be performed, with a best fit obtained by the computer in first approximation called “automatic curve-peeling”. Under special circumstances, recording of the curves, therefore analysis must be limited to a few minutes. This is the case for example when temporary clamping the internal carotid artery for testing the tolerance of the brain to the ischemia during endarterectomy. In such circumstances, the “two minute flow index” is the best approximation that can be obtained to measure the rCBF.

Ricerche citotassonomiche nelle Euphorbiaceae: Euphorbia angulata Jacq. ed E. dulcis L.

Abstract: Cytotaxonomical studies in Euphorbiaceae: Euphorbia angulata Jacq. and E. dulcis L. — E. dulcis and E. angulata can be easily distinguished by the following key: rhizome long, thicker than the stems, swollen and jointed, usually with swellings like ovoid, curved, obliquely jointed bulbils at the base of the stems; ovary and capsule with green or red, uneven tubercles; glands reddish at the anthesis. E. dulcis. rhizome long, jointed, with globular swellings at the base of the stems; ovary and capsule green, with minute hemispherical tubercles; glands yellow at the anthesis … … … … E. angulata. Chromosome number of E. angulata observed in root tips and in gynospore mother cells is n=5, 2n=10. All chromosomes of the complement are M (middle length) type; two pairs bear nucleolar constrictions. The E. angulata embryo sac development is monosporic (Polygonum type) and, moreover, the ovule development differs from that of E. dulcis. New cytological and embryological data are reported about E. dulcis (2...

Testosterone action on glycogen synthesis in the rat levator ani muscle: different inhibitory action of actinomycin D and of cycloheximide.

Abstract: The mechanisms by which actinomycin D and cycloheximide administration prevents the accumulation of glycogen caused by testosterone in the rat levator ani muscle (LAM) have been investigated. Actinomycin D administration only slightly inhibits the effects of testosterone on the xylose uptake and the sugar phosphorylation by the LAM, but it markedly inhibits the increase of the rate of glycogen synthesis by blocking the effect of the hormone on the conversion of glycogensynthetase to the I (physiologically active) form. Evidences have been found indicating that actinomycin D effect might be due to its specific action on RNA synthesis; therefore, even though the interpretation of the effects of inhibitors administered in vivo must be cautious, it is possible to suggest that a normal RNA synthesis is needed to allow testosterone effect on glycogen synthetase to appear. This does not necessarily imply that testosterone acts by inducing enzyme synthesis. Cycloheximide administration leads to a marked inhibitio...

Evaluation of the adhesion to glass of mammalian cells by an electronic particle counter.

Abstract: La velocita di adesione al vetro di cellule KB e stata studiata utilizzando un contatore di particelle elettronico. I risultati mostrano che e possibile studiare l'adesione di cellule al vetro come fenomeno vitale collegato ai fenomeni di attaccamento attivo e di riproduzione cellulare.

Investigation of some non-linear phenomena of induced polarization using a physical-and-mathematical model*

Abstract: The electrical behaviour of a polarizable sample formerly studied (Time-Domain) through both the classical and the condenser methods is simulated using the theoretical responses given by a three dimensional physical-and-mathematical model, which has been proposed in a previous paper by one of us on the basis of certain hypotheses. The apparent capacitance responses of the sample are qualitatively simulated in order to tackle the problem under this point of view; moreover, an attempt to obtain a quantitative simulation of experimental data within the limits of the present reliability of the model, using theoretically obtained Model Master Curves characterized by dimensionless parameters, is done. This research is carried out in the frame of a broader study referring to a possible scheme of simulation of the so-called induced ionic polarization, concerning a number of idealized pseudo-reversible, potentially irreversible, non-linear phenomena. Resume On use un modele physique-et-mathematique pour simuler theoriquement certains endroits du comportement electrique d'un echantillon polarizable, etudiea la fois par la methode classique (“Time-Domain”) et celle du condensateur. Les responses en capacite apparente de l'echantillon sont simulees d'abord qualitativement et ensuite quantitativement, bien entendu dans les limites actuels du modele, en utilisant des familles de courbes theoriques caracterisees par des parametres adimensionnels. Cette recherche est conduite dans le cadre d'un etude sur l'individualisation d'un schema possible de simulation de la polarisation provoquee ionique. Dans ce schema on considere aussi des situations pseudo-reversible, potentiellement irreversible et nonlineaires.

Triple primary malignant neoplasms: uterus, caecum and stomach.

Abstract: A case of triple primary malignant neoplasms is reported: adenocarcinoma of the uterus at age 56 (histerectomy; no radiotherapy); mucinous adenocarcinoma of the caecum and anaplastic carcinoma of the stomach at age 70. The Authors have classified this case as one of multiple primary malignant neoplasms originating in uncorrelated organs. The patient's family history is considered: her mother, a brother, a sister and two daughters died of malignant neoplasms of the digestive system.