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Biomedical subjects

E Manni

Publications and source records attributed to E Manni.

At least 19 recordsLinked to original sources
PubMed1997

Luciani's work on the cerebellum a century later.

In 1891, Luigi Luciani published his famous monograph on the cerebellum and formulated his triad of the cerebellar symptoms: atonia, asthenia and astasia, which explained all troubles provoked by cerebellar lesions; later he added a fourth sign, dysmetria. In spite of the fact that it was advanced in a pre-electrophysiological period, Luciani's interpretation of the cerebellar role in many motor functions survives more than a century later and his terminology has entered the routine of the neurological examination. With the modern knowledge of cerebellar circuitries, we can state that Luciani rightly pointed out the role of the cerebellum in regulating postural tone and muscular force, and that conversely he was wrong in denying cerebellar influence in co-ordination of multi-joint movements and the somatotopic localizations in the cerebellar cortex and nuclei. In spite of this, Luciani's work represents a milestone in cerebellar physiology.

Cerebellum↗
PubMed1997

Otolithic and extraocular muscle proprioceptive influences on the spatial organization of the vestibulo- and cervico-ocular quick phases.

The cervico-ocular reflex (COR) was studied alone or in combination with the vestibulo-ocular reflex (VOR) in the rabbit. Step stimulations of the body with respect to the fixed head induced small slow compensatory responses followed by large compensatory quick phases (QP). These responses remained aligned with the horizon at different head pitch angles. The QP reorientation in space was due to the gravity influence on the otolithic receptors. The vestibular induced QPs exhibit a similar pattern. Because of this reorientation, the reduction of the amplitude of the vestibular induced QPs, due to the addition of the COR, was maintained even at different static head positions. The electrolytic lesion of the ophthalmic branch of the trigeminal nerve deeply affected the space orientation of the COR. In particular, the cervically induced compensatory QPs of the eye ipsilateral to the lesion showed a remarkable variability of their trajectories and they lost space reorientation. These findings suggest that the coordinate system controlling the QPs is influenced by signals originating from both head position in space and eye position in the orbit.

Animals↗
PubMed1996

Influence of the extraocular muscle proprioceptors on the orientation of the vestibulo-ocular reflex.

In the intact brain lamb, unilateral electrolytic lesion of the medial dorso-lateral portion of the semilunar ganglion containing the first order neurons of the eye muscle proprioception induced modifications of the horizontal and vertical vestibulo-ocular reflex (HVOR and VVOR) which consisted in marked alterations of the trajectories of the quick phases, while the slow phases were scarcely affected. Similar results were observed after section of the branches described by Winckler in the retrobulbar region along the extraocular muscle proprioceptive information travels. These findings extend those of previous investigations carried out in decorticate animals.

Animals↗
PubMed1995

Positive action of propionyl-L-carnitine on mechanical performance of papillary muscle from Syrian hamsters with hereditary dilated cardiomyopathy.

Propionyl-L-carnitine has been shown to exert a beneficial effect on cardiac function in different experimental models of cardiomyopathy in the rat, most likely by improving cardiac metabolism and energy production. We have previously shown that, in a strain of hamsters with hereditary dilated cardiomyopathy (BIO TO.2), the mechanical activity of papillary muscle (length-tension, velocity of shortening, shortening, work and power relationship) is significantly depressed when compared to the same parameter in normal hamsters (BIO F1.B). The repeated oral treatment with propionyl-L-carnitine (60 mg/kg per os for 7 weeks) to BIO TO.2 hamsters had a significant positive inotropic effect, as indicated by an increase in developed tension up to the levels observed in papillary muscles from normal hamsters. This action is most likely associated with metabolic effects similar to those observed in rats.

Administration, Oral↗
PubMed1995

Extraocular muscle proprioception and eye position.

In the lamb, acute unilateral section of the ophthalmic branch induced in the ipsilateral eye occasional oscillations of the resting position and misalignment of the horizontal vestibulo-ocular reflex (HVOR) with respect to the stimulus. Additional electrolytic lesion of the cells innervating the proprioceptors of the medial rectus muscle, or of the lateral rectus muscle in the contralateral semilunar ganglion, provoked a 4 degrees-7 degrees consensual eye deviation towards and away from the lesioned side, respectively. The optokinetic beating field was similarly deviated. Under these experimental conditions, HVOR showed enhanced gain and marked misalignment in both eyes. Therefore, the selective suppression of muscular proprioceptive input deviated both eyes towards the direction opposite to the muscle whose gangliar proprioceptive representation has been destroyed.

Animals↗
PubMed1994

[The choice of substrates in total parenteral nutrition].

This review contains a full outline on the choice of substrates in total parenteral nutrition (NPT). The basic properties of "conventional" substrates (glucose, long chain triglyceride-containing fat, common amino acid mixtures) are used to outline the general principles for NPT support in normal conditions and in stress (surgical and nonsurgical trauma, sepsis). Without taking into account factors which are not strictly metabolic (vascular access, local availability of products, costs), particular attention is then paid to "non-conventional" substrates and substrate mixtures, including some under study, with specific reference to properties and features which may motivate their choice.

Amino Acids↗
PubMed1993

Botulinum A toxin effects on rat jaw muscle spindles.

Botulinum A toxin (Botox) is used for the treatment of many muscular dystonias. However, the relief of the sustained and abnormal postures induced by Botox administration is not fully explained. In this work the possibility was considered that Botox can produce a block not only at the alpha motor endings, but also at the gamma motor endings, consequently reducing the spindle inflow to the alpha motoneurons, which have a great role in maintaining the tonic myotatic reflex. Jaw muscle spindle discharge was recorded before and after Botox injection in the deep masseter muscle. The drug consistently reduced the spindle afferent discharge. Such an effect is suggested to be direct on gamma endings as: i) muscle tension was not modified by Botox during the recording time; ii) saline administration never changed the spindle discharge. The Botox effect on muscle spindles suggests that the relief from dystonias could be due not only to a partial motor paralysis, but also to a decrease of the reflex muscular tone.

Animals↗
PubMed1991

Peripheral territory and neuropeptides of the trigeminal ganglion neurons centrally projecting through the oculomotor nerve demonstrated by fluorescent retrograde double-labeling combined with immunocytochemistry.

The peripheral territories of sheep trigeminal neurons which send their central process to the brainstem through the oculomotor nerve were investigated by the use of fluorescent tracers in double-labeling experiments. For this purpose Diamidino yellow (DY) injection into the oculomotor nerve was combined with Fast blue (FB) injection either into the extraocular muscles (EOMs), or the cornea, or the superior eyelid. Double-labeled DY + FB cells were found in the ophthalmic region of the trigeminal ganglion in addition to single-labeled DY or FB cells. The DY and DY + FB-labeled trigeminal cells were analysed immunocytochemically for their content of substance P (SP)-, calcitonin gene-related peptide (CGRP)-, and cholecystokinin-8 (CCK-8)-like. All single-labeled DY cells showed SP-, CGRP- or CCK-8-like immunoreactivity. Double-labeled DY + FB neurons innervating the EOMs were immunoreactive for each of the three peptides, whereas double-labeled neurons supplying the cornea were only CGRP-like positive. The findings suggest that, in the sheep, trigeminal neurons which send their process centrally through the oculomotor nerve supply the EOMs, the cornea, and the superior eyelid and contain neuropeptides which are usually associated with pain sensation.

Animals↗
PubMed1989

Effect of botulinum toxin on extraocular muscle proprioception.

Injections of botulinum toxin type A (BoTox) in one extraocular muscle (EOM) induce long lasting paretic lengthening of the muscle permitting realignment to occur in strabismus, while eye movements appear to be unaffected after the transitory period of induced paresis. It has been hypothesized a BoTox-induced change in the spindle discharge of EOMs to explain the effect in EOM length. In decerebrate lambs and goats, first order neurons of eye muscle spindles were identified in a cellular pool located in the medial dorsolateral portion of the semilunar ganglion. The belly of the muscle to which the recorded unit belonged was infiltrated with BoTox. A decrease in afferent discharge of the spindle and in its stretch sensitivity was observed. This effect began 10-15 minutes after the injection. There was no corresponding decrease in muscle tension during the first 45 minutes. This finding suggests that the block of release of acetylcholine at motor endings is earlier and more efficacious in gamma- than in alpha-motoneurons. As a result of the proprioceptive input reduction, an unbalance between the agonist and antagonist muscles should occur favouring the ocular realignment.

Animals↗
PubMed1989

On the nature of the afferent fibers of oculomotor nerve.

The oculogyric nerves contain afferent fibers originating from the ophthalmic territory, the somata of which are located in the ipsilateral semilunar ganglion. These primary sensory neurons project to the Subnucleus Gelatinosus of the Nucleus Caudalis Trigemini, where they make presynaptic contact with the central endings of the primary trigeminal afferents running in the fifth cranial nerve. After complete section of the trigeminal root, the antidromic volleys elicited in the trunk of the third cranial nerve by stimulating SG of NCT consisted of two waves belonging to the A delta and C groups. The area of both components of the antidromic volleys decreased both after bradykinin and hystamine injection into the corresponding cutaneous region and after thermic stimulation of the ipsilateral trigeminal ophthalmic territory. The reduction of such potentials can be explained in terms of collision between the antidromic volleys and those elicited orthodromically by chemical and thermic stimulation. Also, capsaicin applied on the nerve induced an immediate increase, followed by a long lasting decrease, of orthodromic evoked response area. These findings bring further support to the nociceptive nature of the afferent fibers running into the oculomotor nerve.

Animals↗
PubMed1987

Influence of oculomotor nerve afferents on central endings of primary trigeminal fibers.

Painful fibers running in the third nerve and originating from the ophthalmic trigeminal area send their central projections at level of substantia gelatinosa of nucleus caudalis trigemini. The central endings of these fibers form axoaxonic synapses with trigeminal fibers entering the brain stem through the trigeminal root. The effect of electrical stimulation of the third nerve central stump on the central endings of trigeminal afferent fibers consists in an increased excitability, possibly resulting in a presynaptic inhibition. This inhibitory influence is due to both direct and indirect connections of the third nerve afferent fibers with the trigeminal ones.

Action Potentials↗
PubMed1987

Localization and somatotopy of sensory cells innervating the extraocular muscles of lamb, pig and cat. Histochemical and electrophysiological investigation.

The localization of sensory cells innervating the extraocular muscles (EOMs) was studied in the lamb, pig and cat in which horseradish peroxidase (HRP) was injected into each EOM. Electrophysiological techniques were also used to search for EOM stretch sensitive units in the semilunar ganglion. In lamb and pig labeling was observed in the semilunar ganglion only, while in cat labeled neurons were present in both the semilunar ganglion and mesencephalic trigeminal nucleus. In the semilunar ganglion of all these species a clear somatotopic organization of EOM afferents was observed. The histochemical somatotopic pattern of EOM afferents in the semilunar ganglion of lamb and pig was substantially in agreement with the electrophysiological arrangement. The responses recorded to EOM stretch in the semilunar ganglion of the pig were characterized by a low threshold and a slow adaptation as previously found in the lamb; on the contrary, in the semilunar ganglion of the cat only a few units were found, which showed high stretch threshold and quick adaptation.

Animals↗