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Biomedical subjects

E D Motti

Publications and source records attributed to E D Motti.

17 recordsLinked to original sources
PubMed1996

Clinical and pathological features in hydrocarbon-induced parkinsonism.

A neuropathological examination was performed on a patient with parkinsonism induced by prolonged exposure to a mixture of aliphatic hydrocarbons, mainly n-hexane and halogenated compounds. The patient developed a rapid-course disease that progressed even after withdrawal from the toxic exposure. Pathological examination and immunohistochemical analysis of the brain revealed severe and widespread dopaminergic neuronal loss, associated with severe gliosis, in the substantia nigra, and almost complete loss of tyrosine hydroxylase immunostaining in the striatum. No Lewy bodies were detected. Neuronal loss was also observed in the periaqueductal gray matter, locus ceruleus, and pedunculopontine nucleus. These changes, combined with the moderate anemia due to marrow suppression, and the mild axonal neuropathy observed in vivo, are suggestive of a hydrocarbon toxic insult.

Female↗
PubMed1996

Stereotactic radiosurgery of pituitary adenomas.

The first gamma knife (GK) treatment of a pituitary adenoma in 1967 was meant as an alternative to the primitive surgical approaches that prevailed at the time, with consequent unsatisfactory results. Surprisingly, pituitary adenomas still account for only 7.8% of the 27,000 cases treated in GK centers worldwide. Transnasosphenoidal surgery has greatly improved and surgeons are reluctant to give up a relatively safe and effective operative technique. Radiosurgery is not currently vying to be the primary method of "surgery", but has a definite role following failed pituitary surgery and for tumors that extend into the cavernous sinus. Of 300 patients treated in our GK service, 30 had pituitary adenomas and most had undergone surgery. To date, we have not noted any side effects in the pituitary group. Published information is also reviewed and divided, where possible, into the pre-computed tomography (CT) era and the era of CT-magnetic resonance imaging (MRI). Growth hormone (GH)-secreting adenomas and prolactinomas tend to be larger and cannot be treated with the high doses successful against corticotropin (ACTH)-secreting tumors in Cushing's disease. Radiation fall-off is steep in GK radiosurgery, with the 20% isodose curve being only millimeters away from the point of maximal radiation. The effective dose has mostly been decided on the basis of maintaining safe levels at the sensitive perisellar neural structures. The safety of GK treatment (with no mortality and no permanent morbidity) is compared with other radiosurgical techniques. Good patient response owes much to the cumulative experience of GK pioneers and also to recent advances in images and computers that have enabled increasingly precise stereotaxic targeting and dose planning.

Adenoma↗
PubMed1987

Vasospastic phenomena on the luminal replica of rat brain vessels.

Strikingly localized ring-like constrictions (other than sphincters, cushions and offshoot furrows) have appeared on the casted vessels of some of our preparations. Morphology of the phenomena reveals diverse degree of active contraction of the vessel wall, ranging from corrugation of the luminal surface to near severance of the acrylic cast. Distribution of the vasospastic phenomena reveals as particularly affected the arteries in the diameter range between 25 and 75 micron, that belong either to intra-arterial anastomoses between the branches of each of the three major cerebral arteries or to their terminal junctions in the border zones (inter-arterial anastomoses). Among the possible causes for the occurrence of the observed vasospasms, we indicate the susceptibility to raised intraluminal pressure during injection, producing contraction of the smooth muscle cell. Reactivity appears heightened in the anastomotic districts of the circulation. The evidence of so-called "plastic strips" clinging to constricted sections of affected vessels prompts re-examination of their proposed origin as "plastic wrapping". Rather, they appear to be remnants of dynamic elements of the vascular wall (smooth muscle cells) that resisted corrosion.

Animals↗
PubMed1986

The terminal vascular bed in the superficial cortex of the rat. An SEM study of corrosion casts.

The capillaries in the vascular bed of the rat brain have been investigated by means of scanning electron microscopy of corrosion casts. A technique is described that allowed the finer ramifications to be observed. A series of representative sites from the arteriovenous terminal pathway are described in detail. Contrary to previous reports, the dichotomic pattern of vessel distribution is shown to prevail over the network pattern. Arteriovenous shunts of discrete size were not seen. "Thoroughfare channels" could be recognized. The findings are considered in light of current physiological knowledge, and their significance for microcerebrovascular flow is indicated.

Animals↗
PubMed1986

The capillary bed in the choroid plexus of the lateral ventricles: a study of luminal casts.

Micro-angioarchitecture of the choroid plexus of the lateral ventricles is investigated in microcorrosion casts of animal and human preparations studied with the scanning electron microscope. The capillary bed in the diverse regions of the tissue belongs to one of three patterns: (1)-a network of capillary meshes that envelop the larger arteries and veins predominates in the central segment. (2)-in the villous regions a "leaf-like" organization of sinusoids is found together with (3)-fronds of "glomerular" formations. "Glomeruli" are formed when arterial afferents and venous efferents converge in a quasi hilar structure before branching in arterio-venous loops. Nodular thickenings are observed on glomerular capillaries. The preparations studied (rat, dog, human) are remarkably similar and differ mostly in degree of occurrence of common architectural patterns. Arterio-venous communications are found at the hilus of human glomerular formations.

Adult↗
PubMed1980

Stereo-EEG and surgery in partial epilepsy with temporo-parieto-occipital foci.

Six cases of partial epilepsy operated on for lesions at the temporo-parieto-occipital junction are presented. Three cases had signs of enlargement of one lateral ventricle at the temporo-parieto-occipital carrefour, three had a lateral homonymous hemianopsia and all showed lateralizing interictal EEG abnormalities. The manifold features of the seizures could not be related to the involvement of one or more definite cortical areas. Since clinical, radiological, scalp EEG investigations provided no sufficient data to map the epileptogenic lesion to be excised, stereo-EEG studies with chronic depth electrodes were performed. Besides permitting the exact delimitation of the epileptogenic lesion, depth EEG gave the clue for interpreting physiopathological mechanisms underlying the electroclinical seizures in each case.

Adolescent↗
PubMed1976

Skull changes and intellectual status in hydrocephalic children following CSF shunting.

A total of 76 shunt-treated hydrocephalic children were examined at least once between two and 12-years after surgery to determine what skull changes had occurred and to assess the children's intellectual status. The high incidence of skull changes in shunt-treated, non-tumoral, hydrocephalic children was confirmed. A strict relationship existed between skull changes and low intracranial pressure. The results indicate that impairment of mental development parallels the degree of skull changes, suggesting a close relationship between impaired mental development and cerebrospinal fluid hypotension.

Cerebrospinal Fluid Shunts↗
PubMed1976

Treatment of acromegaly by transsphenoidal microsurgery.

The preoperative outlook and surgical results are evaluated in 29 acromegalic patients, employing the usual serum growth hormone (GH) screening techniques in association with GH response to the thyrotropin releasing hormone (TRH) test. Results obtained by transsphenoidal microsurgical technique in adenomas of different size and sellar morphology are reported. Overall results clearly favor selective microsurgery in early diagnosed and operated tumors (microadenomas), while a less than radical approach does not hold much promise of functional normalization in larger adenomas. In nonnormalized cases the efficacy of radiotherapy is stressed. The TRH test results were a good indication for radiation therapy even in those cases in which GH normalized after surgery by common assay methods.

Acromegaly↗
PubMedDate not supplied

Neuronal generators of the visual evoked potentials: intracerebral recording in awake humans.

Flash and pattern reversal visual evoked potentials were recorded in awake patients undergoing stereotactic procedures for severe dyskinetic disorders resistant to medical treatment. The nucleus ventralis lateralis thalami was reached via an occipital approach. VEPs were recorded on the scalp at the entrance of the intracerebral electrode, and serially from sites at different depths. A polarity reversal of the surface recorded wave form took place as the intracerebral electrode was advanced beneath the surface cortical layers. As concerns F-VEPs, most of the scalp activity mirrored the potentials recorded down to the depth of 70-65 mm from the thalamus. The largest amplitude of intracerebral F-VEPs was obtained from recording sites at 50-70 mm from the thalamus, i.e., in the depth of the calcarine fissure. A negative wave, peaking around 47-50 msec, became evident in recording sites at 30-40 mm from the thalamus but vanished as the electrode was advanced farther. In only one patient could we record a small negative wave, peaking at 33 msec, in the vicinity of the corpus geniculatum externum. Furthermore, the oscillatory activity recorded from the scalp appeared to be generated in the cortical layers. PR-VEPs also underwent polarity reversal as the electrode traversed the cortex. PR-VEPs disappeared more superficially than F-VEPs. No PR-evoked activity could be recorded in the vicinity of the corpus geniculatum externum. We conclude that slow and fast components of VEPs recorded from the scalp are entirely generated in cortical layers.

Brain Mapping↗
PubMedDate not supplied

Percutaneous selective thermorhizotomy in the treatment of "essential" trigeminal neuralgia. The importance of lesion selectivity.

Results following percutaneous thermorhizotomy for trigeminal neuralgia are described in 111 patients. Recurrences and side effects are more frequent whenever selectivity of the surgical lesion has been imperfect (exceeding the original pain area and causing marked hypoesthesia), and less frequent in the cases with strictly selective lesion.

Adult↗
PubMedDate not supplied

Head-holder interfacing computed tomography with Talairach stereotactic frame.

A device is described which allows employ of CT data in conjunction to the Talairach frame for biopsy and other fine localization procedures. A series of new accessory parts allows reversible exact placement of the patient head in the same relative position to the reference system both in the stereotactic frame and the CT machine. No modification has been introduced in the standard Talairach head-holder, preserving its features of simplicity and versatility without need for introduction of new stereotactic methodologies or new computer programs.

Biopsy↗