Evidence for cell proliferation in the sheep brain and its down-regulation by parturition and interactions with the young

Production of new neurons continues throughout life in the subventricular zone (SVZ) and the dentate gyrus (DG) of the hippocampus and is influenced by both endocrine and social factors. In sheep parturition is associated with the establishment of a selective bond with the young based on an olfactory learning. The possibility exists that endocrine changes at parturition together with interactions with the young modulate cell proliferation in the neurogenic zones. In the present study, we first investigated the existence of cell proliferation in sheep. Newly born cells labeled by the cell proliferation marker 5-bromo-2′-deoxyuridine (BrdU) were found in the SVZ, the main olfactory bulb (MOB) and the DG and completely co-localized with Ki-67, another mitotic marker. Forty to 50% of the BrdU-labeled cells contained GFAP suggestive of the presence of neural stem cells. Secondly, parturition with or without interactions with the lamb for 2 days, down-regulated the number of BrdU-labeled cells in the 3 proliferation sites in comparison to no pregnancy. An additional control provided evidence that this effect is specific to early postpartum period: estrus with interactions with males did not affect cell proliferation. Our results provide the first characterization of neural cell proliferation in the SVZ, the DG and unexpectedly in the MOB of adult sheep. We hypothesize that the down-regulation of cell proliferation observed in the early postpartum period could facilitate the olfactory perceptual and memory demands associated with maternal behavior by favouring the survival and integration of neurons born earlier.     

Pre-exposure to ozone predisposes oak leaves to attacks by Diplodia corticola and Biscogniauxia mediterranea

One-year-old cork oak (Quercus suber) and turkey oak (Q. cerris) seedlings were exposed to ozone (110 ppb, 5 h day(-1), for 30 days) and were inoculated with Diplodia corticola and Biscogniauxia mediterranea, respectively, by spraying a suspension of spores on the leaves. Both fungi are endophytic and may act as weak parasites, contributing to oak decline. Ozone exposure stimulated leaf attacks after inoculation, although the physiological, visible, and structural responses of both oaks to O3 exposure were weak. In fact, steady-state gas exchange, leaf waxes, and wettability were not significantly affected by O3. In Q. cerris, O3 altered the structure of stomata, as observed by scanning microscopy, and reduced the leaf relative water content. No hyphal entry through stomata or growth towards stomata was, however, observed. Inoculations were performed in a humid chamber at low light; stomata were likely to be closed. When Q. cerris was inoculated in natural conditions, i.e., in a forest infected by B. mediterranea, seedlings pre-exposed to the enhanced O3 regime had a higher number of B. mediterranea isolates than the controls. This suggests that pre-exposure to O3 predisposed Q. cerris leaves to attacks by B. mediterranea independent of stomata. The hyphae of both fungi were able to enter the leaf through the cuticle, either by gradual in-growth into the cuticle or erosion of a hollow in the cuticle at the point of contact. The primary cause of increased leaf injury in O3-exposed seedlings appeared to be higher germination of spores than on control leaves.     

Basal cells of the frog's taste organ: fluorescence histochemistry with the serotonin analogue 5,7-dihydroxytryptamine in supravital conditions

We utilized the fluorescent serotonin analogue 5,7-dihydroxytryptamine (5,7DHT) to visualize basal cells in the frog's taste organ in supravital conditions. In whole mounts of lingual mucosa, specifical and detailed morphological visualization of fluorescent basal cells was obtained in the peripheral and central region of the intact taste organ; similar results were obtained after mechanical dissociation. Preincubation with serotonin prevented any fluorescence in basal cells. Electron microscopy showed good preservation of the ultrastructural morphology of the taste disk after exposure to 5,7DHT. The advantages of the current method as compared with conventional ones are discussed. This simple, reliable procedure will be useful to further define the biology of neuroendocrine cells in taste as well as in other organs.     

Filippi syndrome: a specific MCA/MR complex within the spectrum of so called "craniodigital syndromes". Report of an additional patient with a peculiar mpp and review of the literature

Filippi syndrome is a specific Multiple Congenital Abnormalities/Mental Retardation (MCA/MR) complex which must not be confused with other so called "craniodigital syndromes", a heterogeneous group of pathological conditions simply lumped for the combination of different cranial and digital anomalies. We report on a new patient with the characteristic features of Filippi syndrome, comparing him with other reported cases and underlining the peculiar and specific shape of the nasal bridge. The metacarpophalangeal profile in our patient is also quite unusual and could be, if confirmed, a good marker of this syndrome.     

The retrograde transport of horseradish peroxidase: problems in the interpretation of its ultrastructural aspects.

In this study we consider critically the use of HRP in research on the ultrastructure of the Central Nervous System. In fact, although controls make by optical microscope on semi-thin sections made us certain that some of the neurons were definitely marked with the enzyme, when the same specimen was observed by electron microscope, in no case was it possible for us to distinguish any particular aspect of the ultrastructural morphology of labelling within neurons.     

Walking Performance: Correlation between Energy Cost of Walking and Walking Participation. New Statistical Approach Concerning Outcome Measurement

Walking ability, though important for quality of life and participation in social and economic activities, can be adversely affected by neurological disorders, such as Spinal Cord Injury, Stroke, Multiple Sclerosis or Traumatic Brain Injury. The aim of this study is to evaluate if the energy cost of walking (CW), in a mixed group of chronic patients with neurological diseases almost 6 months after discharge from rehabilitation wards, can predict the walking performance and any walking restriction on community activities, as indicated by Walking Handicap Scale categories (WHS). One hundred and seven subjects were included in the study, 31 suffering from Stroke, 26 from Spinal Cord Injury and 50 from Multiple Sclerosis. The multivariable binary logistical regression analysis has produced a statistical model with good characteristics of fit and good predictability. This model generated a cut-off value of.40, which enabled us to classify correctly the cases with a percentage of 85.0%. Our research reveal that, in our subjects, CW is the only predictor of the walking performance of in the community, to be compared with the score of WHS. We have been also identifying a cut-off value of CW cost, which makes a distinction between those who can walk in the community and those who cannot do it. In particular, these values could be used to predict the ability to walk in the community when discharged from the rehabilitation units, and to adjust the rehabilitative treatment to improve the performance.     

Photostable pigments within the membrane of photoreceptors and their possible role

In the majority of ommatidia of the fly, the membrane of the central rhabdomere contains — besides the rhodopsin — a photostable pigment. Due to its selective absorption in the blue spectral range, this pigment (possibly a carotene) could modify the spectral sensitivity of the central receptor cells. It furthermore may change the fluidity of the microvillus membrane and hence affect the alignment of rhodopsin molecules. Indirect evidence for a possible role of the photostable pigment as an antenna-pigment for rhodopsin is discussed.Presented at the EMBO-Workshop on Transduction Mechanism of Photoreceptors, Jülich, Germany, October 4–8, 1976     

A kinetic study on the interaction between tazobactam (a penicillanic acid sulphone derivative) and active-site serine beta-lactamases

The interaction between tazobactam and several chromosome- and plasmid-encoded (TEM, SHV, PSE types) class A and C beta-lactamases was studied by spectrophotometry. Tazobactam behaved as a competitive inhibitor or inactivator able to restore in several cases the efficiency of piperacillin as a partner beta-lactam. A detailed kinetic analysis permitted measurement of the acylation efficiency for some cephalosporinases and broad-spectrum beta-lactamases; the presence of a turn-over of acyl-enzyme complex was also evaluated.