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Biomedical subjects

A Antonini

Publications and source records attributed to A Antonini.

At least 19 recordsLinked to original sources
PubMed1992

[The intravascular transfer of glycine during percutaneous kidney surgery].

Transurethral prostatic resection using a 1.5% glycine solution causes a well known clinical and metabolic syndrome called TURP-syndrome. Recent development of percutaneous renal surgery is responsible of several similar accidents. In a prospective study of 150 patients (mean age: 35 +/- 10) subjected to a percutaneous nephrolithotomy, the natremia and the amino acid content of the plasma were measured preoperatively and immediately postoperatively by chromatography. The study shows that there is a post-nephrolithotomy syndrome in two per cent. This syndrome contains a hemodilution with hyponatremia and reabsorption of irrigation fluid. Glycolemia, serinemia and threoninemia increase significantly. These modifications have a good correlation between them except for the natremia. Variability of results in this study and in the literature is explained by difficulty and duration of surgery, volume of glycol used, increasing intrarenal pressures and sudden opening of vessels peroperatively. The gravity of post-nephrolithotomy syndrome requires to change the irrigate solute and use normal saline solution when it is possible.

Adolescent↗
PubMed1992

[Gastric leiomyoma. Our cases].

The authors describe 3 cases of gastric leiomyoma which they observed in the ten-year period 1980-1990. The most important aspects of this pathology are illustrated, emphasizing on one hand the slight incidence, also due to their underestimation, the seat represented by the body and gastric antrum, the asymptomatic submucosal growth or with atypical symptomatology; on the other hand, the low malignant potential linked above all to the voluminous bulk of the neoplasm.

Adult↗
PubMed1991

Uptake of radiocesium by mushrooms.

After the Chernobyl accident in April 1986 the 134Cs, 137Cs and 40K activity of mushrooms of different genera and their corresponding soils from woods located in the province of Umbria (Italy) was determined. The results indicated: a temporally increasing trend for 137Cs up to a "limit value" depending on local fallout in 1986; different cesium concentrations in various mushroom genera; and uptake of potassium from soil that did not appear to compete with cesium uptake. No reliable correlation can be inferred between the cesium content of the soil and those of mushrooms.

Accidents↗
PubMed1991

A procedure for the simultaneous visualization of two anterograde and different retrograde fluorescent tracers. Application to the study of the afferent-efferent organization of thalamic anterior intralaminar nuclei.

The present report describes a method for the simultaneous visualization, in the same structure, of two different sets of afferent pathways and the neurons of origin of some efferent projections. This method has been applied in the cat for studying, in the thalamic anterior intralaminar nuclei, the topographical relationships of afferent arising from the spinal cord and deep cerebellar nuclei with neurons projecting to different cortical areas. Spino- and cerebello-thalamic terminals were anterogradely labeled by injections of the fluorescent dyes fast blue (FB) and 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate (DiI) in the spinal cord and cerebellum. Thalamo-cortical neurons were retrogradely labeled by injections of fluorescent tracers in the precruciate and anterior suprasylvian cortices. The findings show that spinal and cerebellar afferent fibers and the cells of origin of intralaminocortical projections are organized in a clear modular manner and indicate that the method used here is suitable for analyzing simultaneously, in light microscopy, multiple input-output interrelationships of a single structure.

Afferent Pathways↗
PubMed1990

Requirement for subplate neurons in the formation of thalamocortical connections.

The neurons of layer 4 in the adult cerebral cortex receive their major ascending inputs from the thalamus. In development, however, thalamic axons arrive at the appropriate cortical area long before their target layer 4 neurons have migrated into the cortical plate. The axons accumulate and wait in the zone below the cortical plate, the subplate, for several weeks before invading the cortical plate. The subplate is a transient zone that contains the first postmitotic neurons of the telencephalon. These neurons mature well before other cortical neurons, and disappear by cell death after the thalamic axons have grown into the overlying cortical plate. The close proximity of growing thalamocortical axons and subplate neurons suggests that they might be involved in interactions important for normal thalamocortical development. Here we show that early in development the deletion of subplate neurons located beneath visual cortex prevents axons from the lateral geniculate nucleus of the thalamus from recognizing and innervating visual cortex, their normal target. In the absence of subplate neurons, lateral geniculate nucleus axons continue to grow in the white matter past visual cortex despite the presence of their target layer 4 neurons. Thus the transient subplate neurons are necessary for appropriate cortical target selection by thalamocortical axons.

Animals↗
PubMed1990

[Double transplantation of the liver and kidney. A study of curarization using continuously perfused atracurium].

We report the use of atracurium besylate with monitoring of neuromuscular function in a young women with primary hyperoxaluria and no renal function. She underwent orthotopic liver transplantation and also a kidney graft during the same operation. The bolus dose (0.5 mg.kg-1) and the mean infusion rate (0.405 mg.kg-1.h-1) were similar to those reported in references. The infusion rate decreased during anhepatic period. Spontaneous recovery time from TR 25 to 75% was 36 mn and TR 90% was 127 mn, after the end of atracurium infusion. The depression of neuromuscular function was potentiated with isoflurane use, acidemia, hypocalcemia, hypothermia but without cumulative effect. It was concluded that the administration of atracurium by infusion is suitable for long surgical procedures despite impaired hepatic and renal function.

Adult↗
PubMed1989

Effects of terguride in patients with Huntington's disease.

trans-Dihydrolisuride, a partial dopamine receptor agonist, was tested for its effects on chorea in a double-blind, crossover clinical study in 10 patients with Huntington's disease. In eight patients, a neurophysiological evaluation was also performed. No reduction in choreic movements or improvement in voluntary movement performance was observed. However, in some patients, there was a slight improvement in patients' alertness and a reduction of the movement reaction time.

Adult↗
PubMed1988

Subcutaneous lisuride infusion in Parkinson's disease: clinical results using different modes of administration.

The continuous dopaminergic stimulation provided by infusion of dopamine agonist drugs, is a very effective strategy to control ON-OFF fluctuation in Parkinson's disease. Lisuride is a potent dopamine agonist drug, very soluble in water and can be administered subcutaneously. Many authors have shown that the subcutaneous infusion of lisuride can control fluctuations when applied in combination with oral levodopa as a 24 hour continuous infusion regimen. In this study, lisuride was given without any other antiparkinsonian medicament and using a 12 hour infusion regimen wherever possible. 13 fluctuating Parkinsonian patients were studied. 6 out of these 13 were satisfactory treated with lisuride alone and the remaining 7 with a combination of Lisuride + oral levodopa. Only in 3 out of 13 patients the 24 hour infusion regimen was required.

Administration, Oral↗
PubMed1988

[Constant-flow drug administration in anesthesia].

The authors describe a technique of constant flow perfusion of several anaesthetic drugs, using a simple formula to adjust the perfusion rate to the weight of the patients. Calculation of dilutions is easy: the drug concentration is equal to ten times the rate, per hour and per kg, in practical cases. The flow rate is then a tenth of the patient's weight. This method is easy to apply to several drugs, of which pharmacokinetic parameters justify this administration mode: alfentanil, etomidate, vecuronium bromide... but clinical and instrumental observations should be taken into account for the adjustment of the flow.

Alfentanil↗
PubMed1987

Visual and somatosensory integration in the anterior ectosylvian cortex of the cat.

We recorded from single neurons in both banks of the posterior two-thirds of the anterior ectosylvian sulcus. All neurons were tested with visual and tactile stimulations. In each bank of the anterior ectosylvian sulcus the majority of neurons were bimodal, i.e. responded to both visual and tactile stimuli (B cells); the remaining population was strictly unimodal, responding either to visual (V cells) or to somatosensory (T cells) stimulation. Bimodal and unimodal neurons were recorded at all explored cortical sites and were consistently intermixed. Unlike bimodal neurons, unimodal neurons showed an asymmetric localization: the V cells were significantly more numerous in the ventral bank while the T neurons were preferentially found in the dorsal bank of the sulcus. We could not detect an orderly somatotopic or visuotopic representation, nor was it possible to find a systematic spatial correspondence between somatic and visual receptive fields. The functional organization of the anterior ectosylvian cortex is discussed in terms of a hierarchical processing of sensory information.

Animals↗
PubMed1987

Electrophysiological evidence for interhemispheric connections in the anterior ectosylvian sulcus in the cat.

We report electrophysiological data regarding the contribution of the corpus callosum to visual responses in the cortex around the anterior ectosylvian sulcus (AES). The experiments were performed in cats in which the optic input from each eye was surgically restricted to the ipsilateral hemisphere (split-chiasm cats), and where neuronal responses to stimulation of the contralateral eye were mediated by interhemispheric connections. A very high proportion of cells were driven by stimuli presented to either eye indicating that they were activated not only through an intrahemispheric pathway from the ipsilateral eye, but also through an interhemispheric pathway from the contralateral eye. With few exceptions, both receptive fields (RFs) of each binocular neuron abutted or were in the vicinity of the vertical meridian. All neurons responded well to moving stimuli and most of them showed directional selectivity. A few cells were activated by stimuli moving in depth. Following an additional section of the posterior half of the corpus callosum, cells in AES responded only to stimulation of the ipsilateral eye, demonstrating thus that the input from the contralateral eye was conveyed by this part of the corpus callosum. By contrast following a section of the anterior half of the corpus callosum, all visually responsive AES neurons were binocularly activated. These results suggest that the interhemispheric visual input to this ectosylvian region is conveyed via a polysynaptic loop involving visual cortical areas that are connected through the posterior portion of the corpus callosum.

Animals↗
PubMed1986

[Interaction between electrocautery and a pacemaker].

Following a new case of inhibition of a sentinel pacemaker by the cutting current of an electrocoagulator during endoscopic urologic surgery, the mechanism of this complication is recalled. The non-selectivity of the pacemaker detector circuit is responsible for interpreting the electrical disturbances due to the electrocoagulator as cardiac activity. The problems seen with other types of stimulators are discussed, especially programmable stimulation where the use of a magnet can lead to variations in the stimulator frequency. The stimulating wire can also be responsible for accidents, such as myocardial burns, and rhythm disturbances. The safety rules for the use of the electrocoagulator in patients with a non programmable sentinel pacemaker.

Aged↗
PubMed1985

Interhemispheric influences on area 19 of the cat.

Anatomical studies have shown an extensive network of homotopic and heterotopic interhemispheric connections in area 19 of the cat visual cortex (Segraves and Rosenquist 1982a; 1982b). We have investigated their functional organization by recording visual responses in area 19 of cats following a midsagittal section of the optic chiasm. This operation interrupts all crossed optic fibers coming both from the nasal and the temporal retinae; as a result, each hemisphere receives optic fibers only from the lateral hemiretina of the ipsilateral eye which conveys information from the contralateral visual field. Visual information transmitted to the same hemisphere from the contralateral retina and the ipsilateral visual field must be attributed to an indirect, interhemispheric pathway. We found that a rather high proportion of neurons (31.8%) in area 19 of seven split-chiasm cats responded to visual stimuli presented to the contralateral eye. All neurons receiving this interhemispheric activation were also driven by the ipsilateral eye via an intrahemispheric pathway. The property of binocularity was significantly related to the visuotopic map in that both receptive fields of each binocular neuron adjoined or were in the immediate vicinity of the vertical meridian. Due to the small size of receptive fields in area 19, the contribution of the interhemispheric pathway to the representation of the visual field is rather limited and it is certainly less extensive than that predicted by anatomical studies. The representation of the ipsilateral visual field in area 19 of intact cats, as assessed electrophysiologically, was comparable to that found in split-chiasm cats. Recordings in areas 17-18 of split-chiasm cats showed that the visual field represented through the corpus callosum in these visual areas is certainly not less and probably more, extensive than that found in area 19. The results support the conclusion that the relation to the vertical meridian and the receptive field size can explain the organization of the interhemispheric connections in the visual areas studied so far.

Animals↗
PubMed1985

Radon and radon daughter evaluation in a natural radioactivity survey indoors.

An indoor survey in order to estimate the population exposure in five towns of an Italian Region is presented. A particular methodology for the campaign was planned and is being applied. Gamma spectrometry of building materials, exposure rate measurements indoors and outdoors and radon concentration measurements indoors were taken with different techniques. A correlation was found between mean gamma exposure rate and mean radon concentration in the houses investigated. An evaluation of mean effective dose equivalents for the inhabitants of the five towns is reported.

Construction Materials↗