Showing papers by "University of Fribourg published in 1988"

Neuronal activity in the monkey striatum during the initiation of movements

Abstract: The sources of afferent input to the striatum (caudate nucleus and putamen) suggest that this structure may be engaged in neuronal processes related to the initiation of movement. We found that 26% of 508 neurons in both parts of the striatum were activated during the presentation of visual signals which prepared the animals for the execution or withholding of individual arm reaching movements. In a second task, 20% of 382 striatal neurons were activated up to 3 s before self-initiated, non automatic and purposive arm movements which were performed in the complete absence of phasic external stimuli. The data demonstrate an involvement of the striatum in externally and internally generated processes which are related to presetting mechanisms during the initiation of behavioral acts.

Absorption Spectra and Luminescence Properties of Isomeric Platinum (II) and Palladium (II) Complexes containing 1,1′-biphenyldiyl, 2-phenylpyridine, and 2,2′-bijpyridine as ligands

Abstract: The absorption spectra, luminescence spectra, and luminescence lifetimes of the isomeric [M(bph)(bpy)] and [M(phpy)2] complexes M = Pt(II) or Pd(II), bph2− = 1,1′-biphenyl-2,2′-diyl dianion, phpy− = 2-phenylpyridine-2′-yl anion, and bpy = 2,2′-bipyridine have been investigated and compared with those of [M(bpy)2]2+ complexes and of the free protonated ligands H2bph, Hbpy+, and Hphpy. In the absorption spectra, the region below 320 mm is dominated by ligand-centered (LC) transitions, whereas metal-to-ligand charge transfer (MLCT) transitions are responsible for the bands present in the near UV/VIS region. The MLCT bands move to higher energies on replacing Pt with Pd and in going from [M(bph)(bpy)] to the [M(phpy)2] isomer. For the mixed-ligand complexes, evidence for both M bph2− (at higher energies) and M bpy bands is found. The structured luminescence observed at 77 K shows lifetimes of 4.0 and 1.1 μs for [Pt(phpy)2] and [Pt(bph)(bpy)], respectively, and 480 and 250 μs for the analogous Pd complexes. On the basis of the energy and lifetime data, the luminescence of the Pt(II) complexes is assigned to the lowest triplet MLCT excited state, whereas for the Pd complexes the luminescent state is thought to result from a mixture of MLCT and LC triplet levels.

Free-energy dependence of the ion yield of photo-induced electron-transfer reactions in solution

Abstract: A study of photo-induced electron-transfer reactions in MeCN with 9,10-dicyanoanthracene as acceptor and 21 electron donors with transient photoconductivity measurements is reported. The free-ion yield and the rate constant of back electron transfer are determined. For exergonic reactions, the ‘Marcus-inverted’ region is observed. The fit with the theory is best, when a nearly solvent-independent Coulomb term is used in the calculation of the energy balance.

Sensory inputs to the agranular motor fields: a comparison between precentral, supplementary-motor and premotor areas in the monkey.

Abstract: Kinesthetic responses of neurones in the motor cortex, including the primary motor (MI), the supplementary motor (SMA) and the postarcuate premotor (PMC) areas, were investigated in the awake, chronically prepared monkey. In all three subareas, neurones were recorded which responded to passive elbow flexions and extensions induced by a torque motor. In the SMA, such cells were restricted to its posterior portion where intracortical microstimulation produced limb and trunk movements. The majority of SMA cells responds to both displacement directions, a quarter to either flexion or extension. Although the total proportion of SMA neurones responding to arm displacements was low (15%), it was noted that in ‘correct’ somatotopic penetrations, the responsiveness could be prominent. The latency distribution of the kinesthetic responses was similar to that of MI neurones with slightly less response latencies shorter than 20 ms in the SMA. With manually applied stimuli, SMA neurones responded mostly to joint rotations, but not to light cutaneous stimuli. Only two SMA neurones with somatosensory responses were identified as descending projection neurones, and some neurones were found to be modulated also during active grasping. In the PMC, a higher proportion of neurones (27%) reacted to the standardized arm displacements, the majority again responding to both directions. The latency distribution of the kinesthetic responses was similar to that of SMA neurones. In contrast to SMA neurones, many PMC neurones responded to light cutaneous stimuli. It was found that some of the ‘somatosensory’ PMC neurones were sometimes driven also by moving visual and, rarely, by auditory stimuli. Although there are obvious differences in the nature and possibly also in the amount of sensory inputs to the three motor cortical areas, the present results indicate that all three subareas receive somatosensory feedback and that they might therefore all be implicated in the generation of sensorydriven motor output.

Spectroscopic and Electrochemical Behavior of Cyclometalated Pd(II) Complexes

Abstract: The absorption and emission spectra, emission lifetimes, luminescence quantum yields, and electrochemical behavior of the complexes Pd(Phpy)2, Pd(Thpy)2, and Pd(bhq)2 (Phpy−, Thpy−, and bhq−, and bhq− are the deprotonated forms of 2-phenylpyridine, 2-(2-thienyl)pyridine, and benzo[h] quinoline, respectively) have been studied, and the results obtained have been compared with those available for Pt(II) and Pt(IV) complexes containing the same ligands. The intense ligand-centered absorption bands below 340 nm are strongly perturbed by matalation, and the absorption features in the 340–450-nm region are likely to include contributions from formally metal-to-ligand charge-transfer transitions. The structured luminescence spectra observed at 77 K (lifetimes are 0.48, 0.28 and 2.6 ms for Pd(Phpy)2, Pd(Thpy)2, and Pd(bhq)2, respectively) have been assigned to transitions having mainly ligand-centered character, with an increasing metal-to-ligand charge-transfer contribution in going from Pd(bhq)2 to Pd(Phpy)2 and to Pd(Thpy)2. The complexes Pd(phpy)2 and Pd(thpy)2 show two reversible one-electron reduction waves, whereas reduction of Pd(bhq)2 is irreversible, as is the oxidation of the three complexes.

Complexes with a Pincers. 2,6‐Diphenylpyridine as Twofold‐Deprotonated (C ∧ N ∧ C) terdentate ligand in C,C‐trans‐, and as mono‐deprotonated (C ∧ N) chelate ligand in chiral C,C‐cis‐complexes of platinum(II) and palladium(II). Preliminary communication

Abstract: A2,6-Diphenylpyridine forms, as twofold-deprotonated, terdentate ligand, complexes with Pt(II) and Pd(II), having two adjacent five-membered metallocycles. As mono-deprotonated, bidentate ligand, it forms cis-bis-complexes having a chirality axis. Pt(II) complexes undergo thermal and photochemical oxidative addition reactions, yielding stable Pt(IV) compounds. Pd(II) complexes yield substitued 2,6-diphenylpyridine in photochemical reactions.

Origin of the specific H reflex facilitation preceding a voluntary movement in man.

Abstract: 1. In a reaction time situation, the monosynaptic spinal reflex (H reflex) is facilitated before the onset of an electromyographic (EMG) response. The aim of the present investigation was to test if the facilitation can be attributed either to a subliminal depolarization of motoneurones or to an increase of the excitatory effect of the afferent volley reaching the motoneurones. 2. At the onset of an acoustic warning signal, human subjects were required to concentrate on a reaction time task and, in addition, to initiate a steady isometric plantar flexion of medium intensity in both feet. In response to a following visual stimulus, they carried out a ballistic plantar flexion randomly with the right or left foot. At different times after the visual reaction signal, H reflexes were elicited bilaterally. 3. The facilitation of the H reflex was similar in the presence and absence of a steady activation. In addition, the facilitations were similar in absolute amplitude and duration when the stimuli evoking the H reflexes were at threshold intensities, or at an intensity which produced control H reflexes of 60% maximum amplitude. 4. In a second series of experiments, no H reflexes were elicited but the strength of the steady plantar flexion was varied. Premotor time, i.e. the interval between the onset of the visual stimulus and the EMG response, and reaction time, i.e. the interval between the onset of the visual stimulus and the mechanical response, were computed. Neither parameter depended significantly on the intensity of steady flexion and they were the same with steady flexion as without. 5. The rectified EMG records and the torque records were aligned by the end of premotor time. Three-dimensional displays of average activity as a function of time and steady activation level were computed. No activation before premotor and reaction time was detected which could have been related to the H reflex facilitation. 6. The present results suggest that all motoneurones, in particular those being activated during the voluntary contraction, can contribute to the H reflex facilitation before movement onset and that the basis of this facilitation is an enhanced excitatory effect of the afferent volley elicited by the H reflex stimulus. Mechanisms leading to the facilitation could be removal of presynaptic inhibition at I a terminals or facilitation of interneurones intercalated in polysynaptic components of the reflex pathways.

MPTP-induced parkinsonism in monkeys: mechanism of action, selectivity and pathophysiology.

Abstract: A new era in research on parkinsonism began a few years ago when a number of younger patients was detected who had developed severe and irreversible parkinsonism after abuse of a meperidine cogener containing 1-methyl-4-pbenyl1,2,3,6-tetrahydropyridine (MPTP) (Davis et al., 1979; Langston et al., 1983). The symptoms largely replicated those of idiopathic parkinsonism, and further parallelisms included the destruction of nigrostriatal dopamine (DA) neurons, changes of biogenic amine metabolites in cerebrospinal fluid, response to DA precursor or agonist drug therapy, on-off phenomena and druginduced dyskinesia (Ballard et al., 1985).

Relation between intestinal alkaline phosphatase activity and brush border membrane transport of inorganic phosphate, D-glucose, and D-glucose-6-phosphate

Abstract: In order to evaluate the role of the alkaline phosphatase in intestinal transport processes, we studied the influence of known modulators of the alkaline phosphatase (polyclonal anti-calf AP antibodies, theophylline and zinc ions) on the absorption rate of glucose, inorganic phosphate and glucose liberated from glucose-6-phosphate into calf duodenal brush border membrane vesicles. Our results allow the following conclusions: First a direct involvement of the AP in the Na+-dependent glucose absorption is unlikely. Indeed, theophylline inhibits strongly the AP activity but rather stimulates the glucose uptake; second the AP is indirectly involved in glucose absorption from glucose-6-phosphate, if its enzymatic hydrolysis is the only source of glucose. In that case the Na+-dependent uptake of glucose was completely suppressed either by phosphatase specific antibodies or by theophylline; third the positive correlation found with calf intestinal BBMV between the inhibition of AP by AP antibodies or by theophylline and the decrease of rate of Na+-dependent Pi uptake rate suggests that the enzyme plays some role in the Pi absorption. It appears from the present study that the AP is probably not a carrier protein itself, but its hydrolytic activity might nevertheless be important for intestinal absorption. After hydrolysis of phosphoric esters the alcohol residues and Pi can be supplied to their specific carriers. Furthermore, the high Pi affinity of the enzyme at physiological pH values, could even favour a transient sequestration of phosphate, which then could be transferred to the Pi carrier.

Prototyping an interactive electronic book system using an object-oriented approach

Abstract: An Integrated Electronic Book (IEB) represents a complex network of integrated information and "know how" on a given subject. In the design phase of WEBS (Woven Electronic Book System), we soon realized that, because we were describing the IEB in terms of "objects" and "methods," and because we wanted WEBS to be easily expandable and to offer a consistent user interface, we should use an object-oriented development system.This paper does not fully discuss the concept of electronic book systems, but rather describes our own experiences developing a complex software system with an object-oriented language. The first part explains our choice of an object-oriented language and software framework. The rest describes the software architecture of WEBS, which is a class hierarchy of three layers: a software framework (MacApp) layer, a system-specific layer, and an application-specific layer.

Nuclear polarization and charge moments of 208Pb from muonic x rays.

Abstract: Muonic transition energies between low-lying states in ${\ensuremath{\mu}}^{\mathrm{\ensuremath{-}}}$${\mathrm{\ensuremath{-}}}^{208}$Pb have been measured in a precision experiment using a Compton suppression spectrometer. Nuclear charge parameters and nuclear polarization corrections have been adjusted to the data. In particular, experimental correlations between the nuclear polarization corrections of the lower muonic levels have been established. A set of nuclear charge parameters reproducing all the experimental transition energies can only be obtained by assuming an inversion in magnitude of the nuclear polarization corrections not only for the 2p states, but also for the two 3p states. Such a result is unexplained by present theoretical models, but corroborates the findings of a recent experiment concerning the 2p states in ${\ensuremath{\mu}}^{\mathrm{\ensuremath{-}}}$${\mathrm{\ensuremath{-}}}^{90}$Zr. Using our best-fit parameters, a $^{208}\mathrm{Pb}$ rms radius of 〈${r}^{2}$${〉}^{1/2}$=5.5031(11) fm has been obtained.

LPL: A Structured Language for Linear Programming Modeling

Abstract: This paper describes a specialized programming language, named LPL (Linear Programming Language), which may be used to build, modify and document LP models. The LPL language has been successfully applied by the authors to generate automatically MPSX input files of large LP models. The LPL Compiler translates LPL programs, which represent concise and readable LP models, into two internal files. These files may be translated into an explicit equation listing, a picture (matrix layout) or the MPSX input file. LPL includes also a link to the popular relational database management system dBASEIII, which allows the LPL Compiler to read data, used in the LP model, directly from databases.

Dumond curved crystal spectrometer for in-beam X- and gamma-ray spectroscopy

Abstract: An in-beam curved crystal spectrometer facility has been installed at the SIN variable energy cyclotron. The radius of curvature is 3.15 m. Using the (110) planes of different bent quartz laminas, diffraction peaks down to Δθ = 5 arcsec FWHM are obtained. The energy resolution is thus ΔE ⋍ 0.01 E 2 /n , where n is the diffraction order, ΔE being expressed in eV and E in keV. The spectrometer has been constructed to cover an angular range of ±10°. Transitions in the range 17 to about 350 keV have so far been observed. Measurements have been performed in conventional line source DuMond geometry and in slit geometry. The instrument is being used for the high-resolution observation of X- and gamma-rays induced by proton, helium- and oxygen-ion bombardment.

Transformations of the retinal topography along the visual pathway of the chicken.

Abstract: It is still unclear how the retinotectal map of the chick is formed during development. In particular, it is not yet known whether or not the organization of fibres plays a role in the formation of this map. In order to contribute to the solution of this problem, we analysed the representation of the retinal topography at closely spaced intervals along the fibre pathway. We injected HRP into various sites of the tectal surface and traced the labelled fibre bundles back to the retina. The retinal topography was reconstructed at ten different levels, i.e. in the retina, the optic nerve head, the middle of the optic nerve, the chiasm (three levels), the optic tract (three levels), and the optic tectum. We obtained the following results: (1) The labelled fibre bundles as well as the fields of labelled retinal ganglion cells were always well delimited and coherent. (2) The reconstructions show that transformations of the retinal topography occur in the fibre pathway. The first and most important transformation is found in the optic nerve head where the retinal image is mirrored across an axis extending from dorsotemporal to ventronasal retina. In addition, the retinal representation is split in its temporal periphery. Thus, central and centrotemporal fibres are no longer in the centre of the image but close to the dorsal border of the nerve. Peripheral fibres are found along the medial, ventral and lateral circumference of the nerve. In the optic tract a second transformation occurs. The retinal topography is rotated clockwise by about 90 degrees and flattened to a band. The flattening is accompanied by a segregation of fibre bundles so that eventually central and centrotemporal retinal fibres are located centrally, ventral fibres dorsally and dorsal retinal fibres ventrally in the tract. By these two transformations an organization of fibres is produced in the optic tract which can be projected onto the tectal surface without major changes given that dorsal and ventral fibres remain in their relative positions, and that deep lying fibres project to the rostral and central tectum, superficial fibres to the caudal tectum. The transformations which we have observed follow specific rules and thus maintain order in the pathway although retinotopy is lost. In conjunction with our earlier studies on the development of the retinotectal system we conclude that fibres are laid down in a chronotopic order. The transformations take place under particular structural constraints.(ABSTRACT TRUNCATED AT 400 WORDS)

The modelling of nucleophilic and electrophilic additions to organometallic complexes using molecular graphics techniques.

Abstract: A new formalism has been developed in order to evaluate intermolecular interaction energies for inorganic and organometallic complexes in the framework of the extended Huckel method. In order to provide the shortest possible response time on an interactive computer graphics facility, this model should require the minimum amount of computer time, which explains why approximate procedures are used to evaluate electrostatic, charge transfer and exchange repulsion components. When applying this model to typical examples of electrophilic addition reactions to organometallic complexes, it is found that it is essential to take account of charge transfer interactions, the electrostatic component alone being not sufficient, even qualitatively, for a proper description of the reaction mechanism. The results, presented as color-coded dot molecular surfaces, show a very good agreement with experiment as to the site of attack, namely (i) on metal for the electrophilic attack on Fe(cp)2, Fe(CO)5 and X(cp)(CO)2, X = Co, Rh; (ii) on the cp ligand for the nucleophilic attack on Co(cp)2+ and Rh(cp)2+; (iii) on bz for the nucleophilic attack on Fe(cp)(bz)+. Finally, modellizations of the nucleophilic attack on a coordinated olefin and of the relation between structure and acidic properties of zeolites are presented and discussed.

Callosal projections between areas 17 in the adult tree shrew (Tupaia belangeri).

Abstract: In the primary visual cortex (area 17) of the tree shrew (Tupaia belangeri) neurons projecting to the contralateral area 17 via the corpus callosum were identified by horseradish peroxidase histochemistry (HRP, WGA-HRP). The distribution of homotopic and heterotopic connections was studied. We found that a narrow stripe of area 17 close to the dorsal area 17/18 border — which corresponds to the visual field along the vertical meridian — is connected via homotopic callosal projections. The adjacent dorsal part of area 17, which largely corresponds to the binocular visual field, is connected via homotopic as well as heterotopic projections. Heterotopic projections originate in the cortical stripe along the area 17/18 border and their contralateral targets are displaced medially. Callosal neurons are located mostly in supragranular but also occur in infragranular layers. The supragranular neurons in general are pyramidal cells. In addition to these findings, we confirmed earlier reports on ipsilateral projections of the primary visual area to the dLGN, the claustrum, area 18 and other visual areas.

The Radical Cation of Cyclobutene and its Photoproduct. Preliminary communication

Abstract: The hitherto unknown radical cation of cyclobutene (2) has been generated in a CFCl3 matrix by γ rays at 77 K. The coupling constants, as determined from the ESR spectrum of 2+, are 2.80 and 1.11 mT for the four CH2 and the two CH = protons, respectively. Photo-induced ring opening of 2+ yields a radical cation which exhibits the same ESR and ENDOR spectra as those observed upon direct ionization of s-trans-buta-1, 3-diene (s-trans-1). The radical cation s-trans-1+, should, therefore, be the final product of this conversion.

Surface properties and electronic structure of amorphous Zr 75 Ni 25 and Zr 75 Ni 25 hydride studied by photoemission

Abstract: We have studied the surface composition of melt-spun amorphous Zr/sub 75/Ni/sub 25/ ribbons by means of x-ray-photoelectron-spectroscopic core-level analysis and depth profiling and the electronic structure of carefully cleaned Zr/sub 75/Ni/sub 25/ and of Zr/sub 75/Ni/sub 25/ hydride by means of valence-band and core-level analysis. We observed strong oxygen-induced segregation in a surface layer on both sides of the ribbons. On ribbons which were kept in air for three years the surface layer is much thicker (approx. =60 nm) on the dark (wheel) side, suggesting enhanced corrosion. In contrast, we see no significant segregation due to hydrogen adsorption or absorption, but the appearance of the hydrogen-induced bonding band centered at 6.5 eV below E/sub F/, a shift by 0.6 eV of the Zr 3d line, and a weak loss of asymmetry of the Ni 2p line upon hydride formation. We conclude that neither the oxygen- or hydrogen-induced segregation effects nor the electronic structure of amorphous Zr/sub 75/Ni/sub 25/ and Zr/sub 75/Ni/sub 25/ hydride differ radically from those of corresponding crystalline alloys.

Conditional Belief Structures

Abstract: The mathematical theory of evidence (Shafer et al. [9]) has recently found much interest as an approach to treat uncertainty in expert and knowledge-based systems. Although the theory is very promising, there are not yet many practical applications. Modeling practice has still to be developed. This is a crucial task in view of facilitating the application of evidential modeling. It is the aim of this paper to discuss an important element of evidential modeling—conditional belief—within the scope of the mathematical theory of evidence. In a given problem domain, there exist in general domain dependent, structural knowledge about various relations between different aspects or elements of the problem. On the other hand, there are several sources of information or knowledge, which produce evidence about various facets of the problem in a given context or situation. This observational evidence must then be combined with the structural knowledge. Any model within the mathematical theory of evidence is based on a. frame of discernment 0, a finite set whose elements represent the possible outcomes or results. Often the reasoning is about different objects, different attributes or properties of an object, or more generally about different variables related to a problem. It is then natural to consider 0 as a product set formed by several factor frames 0,, each one representing the possible values of one variable. The structural knowledge in such models is then contained in relations between different variables or different factor frames 0,. Such relations may take the form of conditional belief structures. Intuitively, these structures describe the beliefs about propositions in 0y, given certain propositions in 0,. The exact mathematical definition of these conditional belief structures is the first goal of this paper.

The study of prompt and delayed muon induced fission

Abstract: The mean life times of negative muons bound to actinide nuclei have been measured by detecting the time difference between a stopped muon and the arrival of fragments from delayed fission after muon capture. The deduced capture ratesΛc are 1.392(4)·107/s for237Np, 1.290(7)·107/s for242Pu and 1.240(7)·107/s for244Pu. The results are compared with published data for the fission and the neutron decay channels and for the electron decay of the bound muon. Including a former measurement ofΛc for239Pu, an isotopic dependence of the muon capture rates in the Pu isotopes is clearly observed.

Coupling of active sodium transport to oxidative metabolism in the rabbit distal colon.

Abstract: 1. Active transepithelial Na+ transport (Ji) and O2 consumption (Jr) were measured simultaneously in rabbit distal colon, under standard (control) incubation conditions and after various manoeuvres, known to inhibit Na+ transport. 2. The determination of Jr was complicated by the presence of fluctuations of the PO2 in the incubation solution and by spontaneous variations of the tissue respiration, which usually declined slowly with time. 3. The control values of Ji and Jr after 2 h incubation were 55 +/- 4 nequiv min-1 cm-2 and 16 +/- 1 nmol O2 min-1 cm-2, respectively (n = 44). The electrical resistance was 386 +/- 23 omega cm2; it was stable over 6 h. 4. Ji was reduced to a very low level with either amiloride, ouabain or Na+ substitution with choline. In all instances, Jr decreased concomitantly by 15-30%. 5. A plot of the change in Jr versus the change in Ji gave a straight line for all situations, i.e. for the spontaneous decline of Na+ transport and respiration and for the effects of the inhibitors. 6. The linearity between Jr and Ji allows for the determination of a stoichiometric ratio. It is of similar magnitude, when calculated either with the data of spontaneous variations or with those obtained by the action of any inhibitor tested. It is 15-20 Na+ ions per O2 molecule, a value close to that reported previously for amphibian epithelia and also close to the maximum theoretical value of 18 Na+ ions per O2 molecule.

The Magnetization Density of Hexacyanoferrate(III) Ion Measured by Polarized Neutron Diffraction in Cs$_2$KFe(CN)$_6$

Abstract: A polarized neutron diffraction experiment on Cs 2 KFe(CN) 6 gave 292 unique magnetic structure factors. These were analysed by using a model for the magnetization density of multipoles and valence functions on the iron and ligand atoms, with the dipole approximation for orbital effects. Neither the ligand nor the iron atom densities retain the cubic symmetry of the free ferricyanide ion. The natural axes of quantization of the iron atom are rotated by significant amounts from the Fe-CN vectors. The iron electronic configuration was found to be d -0.64(8) xy d 0.78(6) xz d 0.72(5) yz d -0.06(6) z 2 d 0.17(7) x 2 - y 2 corresponding to the cubic t 5 2g configuration of the low-spin d 5 Fe III ion perturbed to put all spin in the d xz and d yz orbitals. The negative spin in the d xy orbital and the 6% of negative spin on the carbon atoms conform with the qualitative predictions of previous ab initio theoretical calculations, although for d xy there are large manifestations of spin polarization. The 12% of spin delocalized onto nitrogen atoms reflects covalence. The ligand populations depart considerably from those for cubic symmetry, and can be understood in terms of spin occupation of molecular orbitals involving 3d-t 2g orbitals with coefficients d xy xz yz . These observations can be rationalized by an empirical model in which the ligand field components exerted by the cyanide groups are influenced by details of the crystal structure.

The Morphological Basis for the Polster Theory of Penile Vascular Regulation

Abstract: The discovery of the papaverine erection test by Virag in 1982 stimulated the interest of research workers in the physiology of the penis. Since then, the scheme of functioning proposed by Conti [Acta anat. 14:217–262,1952] in 1952 has been frequently cited in the literature, although its finalism is evident. It is based upon the presence of regulatory mechanisms along penile arteries, veins and arteriovenous anastomoses. In spite of the fact that these anastomoses were unanimously admitted, recently the presence of arterial and venous cushions has been controverted or even denied. Before attempting any functional explanation using nerves and chemical mediators, we made sure first of the concrete material reality of these anatomical structures.Thirty-five years after the main study, the present observations confirm the morphologic descriptions made in 1952.The contrary would have been astonishing. In fact, arterial and venous cushions were demonstrated by the School of Anatomy of Padova, the most ancient and venerable of all (Fallope, 1550), then by other institutes of morphology that dealt with these cushions in practically all the organs of the human body. It remains to establish their role in erection – whether it is null, complementary or primordial: that is the question.

Comparison of fructosamine and glycated haemoglobin in children with Type 1 (insulin-dependent) diabetes mellitus

Abstract: In six children (age: mean 8.4 years, range 2.2–12.6 years) with newly diagnosed Type 1 (insulin-dependent) diabetes mellitus, plasma fructosamine and glycated haemoglobin (HbA1) were compared in respect to their disappearance during the first month after diagnosis during well controlled glycaemia. The disappearance of the surplus plasma fructosamine and HbA1 was calculated applying exponential equations. The estimated half-lives of fructosamine (mean 57.2 days, range 40.7–77 days) and HbA1 (mean 59.7 days, range 43.3–82 days) were not significantly different, a finding which is left unexplained.

Level structure of the doubly-odd 242Am nucleus.

Abstract: The level structure of the doubly-odd /sup 242/Am nucleus was investigated by means of thermal-neutron-capture gamma-ray and conversion electron spectroscopy. Pair, curved-crystal, and ..beta.. spectrometers were used. The data from these measurements, combined with previous direct reaction results, permit us to establish a detailed level scheme including six new well-developed bands. Our experimental results are interpreted in the framework of the Nilsson model. Precise Gallagher-Moszkowski splittings and Newby odd-even shifts extracted from the data are compared with theoretical calculations.