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Exposure to reduced gravity impairs junctional transmission at the semicircular canal in the frog labyrinth
No full textThe effects of microgravity on frog semicircular canals have been studied by electrophysiological and morphological approaches. Reduced gravity (microG) was simulated by a “random positioning machine” (RPM) which continually and randomly modified the orientation in space of the anesthetized animal. As this procedure stimulates the semicircular canals, the effect of altered gravity was isolated by comparing microG-treatment with an identical rotary stimulation in the presence of normogravity (normoG). Electrophysiological experiments were performed in the isolated labyrinth, extracted from the animals after the treatment and mounted on a turntable. Junctional activity was measured by recording quantal events (mEPSPs) and spikes from the afferent fibers close to the junction, at rest and during rotational stimulation. MicroG treated animals displayed a marked decrease in the frequency of resting and evoked mEPSP discharge, versus both control and normoG (mean decrease ~50%). Spike discharge was also depressed: 57% of microG-treated frogs displayed no spikes at rest and during rotation at 0.1 Hz, vs. 23-31% of control or normoG frogs. Among the firing units, during one cycle of sinusoidal rotation at 0.1 Hz microG treated units emitted an average of 41.8 +/- 8.06 spikes, vs. 77.2 +/- 8.19 in controls. Patch-clamp analysis on dissociated hair cells revealed altered Ca2+ handling, after microG, consistent with and supportive of the specificity of microG effects. Marked morphological signs of cellular suffering were observed after microG, mainly in the central part of the sensory epithelium. Functional changes due to microgravity were reversible within a few days
Ultrastruttura del residuo mucopolisaccaridico dopo estrazione con cloruro di guanidinio
No full text
Morphology of epiphyseal apparatus of a ranid frog (Rana Esculenta).
Full text linkMorphological, histochemical and
ultrastructural investigations on epiphyseal apparatus
of Rana Esculenta were made. The most important
findings were the following: 1) metaphyseal cartilage is
localized inside proximal diaphyseal compact bone as
a plug; 2) metaphyseal cartilage do not reduce in
thickness during ageing; 3) metaphyseal cartilage do
not show vascular invasion and do not mineralize in
degenerative zone; 4) trabecular bone was not at al1
evident in this animal; 5) externa1 periosteum is well
vascularized and proliferates in correspondence to
marginal epiphyseal end of the diaphyseal.
From these results the hypothesis that the ranid
frog bone growth is not due to metaphyseal
metabolism (as in avian and mammals) but to bone
periosteal marginal mineralization is reached
Antiinflammatory and antiphlogistic action of bicarbonate-calcium-magnesium thermal water when applied to skin treated with TCA 25%.
No full textABSTRACT - Chemical peeling induces a controlled stratum corneum sloughing which results
both in varying degrees of desquamation, stimulation and epidermal regeneration, and in consistent
derma repair and new collagen formation. The most common side-effect is infiammation. Usually,
to reduce or control infiammation, an emollient cream sometimes containing antibiotics or sterolic
extracts is applied. However it is khown that natural anti-infiammatory agents exist in bicarbonatecalcium-
magnesium thermal water. The aim of our research was to study the anti-infiammatory and
antiphlogistic action of bicarbonate-calcium-magnesium thermal water when applied to the skin of an
albino rabbit treated with TCA 25%, a potent exfoliant, and then treated with a cold pack ofmineral
waters. The degree of infiammation was analysed 24 hours using histological and digitalic evaluation.
In both cases, the skin treated with natural water was significantly less infiamed than the untreated
skin. However, the skin treated with thermal waters was even less infiamed than both the untreated
skin and the skin treated with natural water. These anti-infiammatory effects are probably due to •
the buffer activity the bicarbònate-calcium water (Comano Terme) has, and to its rehydrating effect
observed in experimental burning
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