PubMed Health⌕ Search

Biomedical subjects

L Casini

Publications and source records attributed to L Casini.

12 recordsLinked to original sources
PubMed1997

The basic pattern of activation in motor and sensory temporal tasks: positron emission tomography data.

Positron emission tomography (PET) data were obtained from subjects performing a synchronization task (target duration 2700 ms). A conjunction analysis was run to identify areas prominently activated both in this task and in a temporal generalization task (target duration 700 ms) used previously. The common pattern of activation included the right prefrontal, inferior parietal and anterior cingulate cortex, the left putamen and the left cerebellar hemisphere. These areas are assumed to play a major role in time processing, in relation to attention and memory mechanisms.

Adult↗
PubMed1997

Effects of attention manipulation on judgments of duration and of intensity in the visual modality.

The "attentional model" of time estimation assumes that temporal judgments depend on the amount of attention allocated to the temporal processor (the timer). One of the main predictions of this model is that an interval will be judged shorter when attention is not allocated to the temporal parameters of the task. Previous studies combining temporal and nontemporal tasks (dual-task method) have suggested that the time spent processing the target duration might be a key factor. The less time devoted by the subject to the temporal task, the shorter the judged duration. In the two experiments presented here, subjects were asked to judge both the duration of a visual stimulus and an increment in intensity occurring at any time during this stimulus. In the second experiment, trials without intensity increments were added. The main result is that the judged duration was shorter when the increment occurred later in the stimulus or did not occur. In those cases, subjects had been expecting increment occurrence during most part of the stimulus and thus had focused for a shorter time on stimulus duration. We propose that attention shifts related to expectancy and to detection of the increment reduce subjective duration.

Adult↗
PubMed1996

Can the level of prefrontal activity provide an index of performance in humans?

The experiment reported here was aimed at determining whether the level of brain activity can be used as an index of subjects' performance on a temporal task. The discrimination of durations constituted the task. An array of four A's appeared on a screen, and subjects had to decide whether the letters remained on the screen for a short or a long duration as learned in a practice phase. This task allowed us to compare the level of brain activity obtained in correct and incorrect responses. The current density measures recorded over prefrontal areas showed that the level of activity obtained with correct responses was lower than those obtained with incorrect responses. This suggests that a good performance could be the result of an economic, but efficient, information-processing mechanism in the brain.

Adult↗
PubMed1996

Brain activation induced by estimation of duration: a PET study.

Duration information about a visual stimulus requires processing as do other visual features such as size or intensity. Using positron emission tomography, iterative H215O infusions, and statistical parametric mapping, we investigated the neural correlates of time processing. Nine normal subjects underwent six serial rCBF. Three tasks were studied: (a) A temporal generalization task (D task) in which the subjects had to judge (by pressing one of two keys) whether the duration of the illumination of a green LED was equal to or different from that of a previously presented standard; (b) An intensity generalization task (I task) in which the judgment concerned the intensity of the LED; and (c) A control task (C task) in which the subjects had to press one of the two keys at random in response to LED illumination. A significant increase in rCBF during the D task, compared to that during the C task, was observed in right prefontal cortex, right inferior parietal lobule, anterior cingulate cortex, vermis, and a region corresponding to the left fusiform gyrus. A significant increase in rCBF during the I task, compared to that during the C task, was observed in right prefontal cortex, right inferior parietal lobule, right extrastriate cortex, anterior cingulate cortex, left inferior parietal lobule, vermis, and two symmetrical regions corresponding to the fusiform gyri. No significant activation was observed in the D task when compared to that in the I task. We propose that these cortical maps are best explained by the recruitment of visual attention and memory structures, which play a major role in prospective time judgements as indicated by behavioral studies. The data also suggest that the temporal dimension of a visual stimulus is processed in the same areas as other visual attributes.

Adult↗
PubMed1996

Daily fluctuations of haematology and blood biochemistry in horses fed varying levels of protein.

Changes in the plasma biochemistry of 12 stallions were studied over seven 24 h periods. Twelve healthy male horses of 4 different breeds (Thoroughbred [TB], Anglo-Arabo-Sardo [AAS], Avelignese [Av] and Maremmano [M]) were divided into 3 experimental groups and fed with an isoenergetic maintenance ration with different protein levels. The same amount of food was given daily at 0730 and 1930 h. After 20 days of pretrial, a series of 6 blood samples were collected daily from the jugular vein every 4 h for 7 days. The samples were analysed for packed cell volume (PCV), haemoglobin, plasma glucose, free fatty acids, cholesterol, total plasma protein, urea, creatinine, calcium, phosphorus and enzymatic activities: aspartate aminotransferase (AST), alanine aminotrasferase (ALT), creatine kinase (CK) and lactate dehydrogenase (LDH). The data were analysed following the armonic analysis (Fourier) in order to define the pattern of biorhythm. Many parameters showed a biorhythmical pattern. Protein levels of the diet failed to influence haematology, blood biochemistry and biorhythm. Thoroughbreds showed the highest values of PCV, haemoglobin and creatinine and the lowest total protein, phosphorus and enzymatic activities.

Analysis of Variance↗
PubMed1996

[The laryngeal mask in pediatric anesthesia].

We carried out a perspective study in order to assess the ease of insertion, the type and the incidence of perioperative complications connected with the use of the Laryngeal Mask Airway (LMA). We examined 300 consecutive patients, M/F 261/39, average age 4.2 yrs. (range 0.1-16), ASA I-II, who underwent surgical operations of short or average length not involving the pleural, the oropharyngeal or the peritoneum cavity. The choice about anesthesia was left to the discretion of the anesthesiologist. In 27 cases the position of the LM was controlled through a flexible fiberoptics. In 269 patients (89.6%) the LMA was correctly positioned during the first attempt. In 27 patients (9%), 2 or more attempts were necessary, and in 4 patients (1.4%) it was not possible to set the LMA. No differences of statistical significance were noticed between the different size of LMA, with regards to the facility of insertion. The control through fiberoptics showed a correct position, from an anatomical point of view, in 11 patients (41%), whereas in 13 patients (48%) some signs of partial obstruction were noticed (epiglottis interposing between the opening of LMA and larynx) and in 3 patients (11%) vocal cords are not visible. The following complications took place: laryngeal spasm on induction (2.3%), cough or movements on positioning (2.3%), hypoxia (4.3%), obstruction (1%), laryngeal spasm on awakening (1.7%), trauma (5%) and vomiting (0.3%). No connections were found between the size of LMA and total complications. Nevertheless, cough or movement during positioning and laryngeal spasm on awakening were significantly more frequent with LMA n. 3. In our experience, the LMA proved to be effectual and safe in the control of the airway during elective operations in pediatric surgery.

Adolescent↗
PubMed1994

Controlled attention sharing influences time estimation.

A seminal attentional model of time estimation predicts that subjective duration will be positively correlated to the amount of attention given to temporal processing. This prediction holds under prospective conditions, in which one is forewarned that judgments of time will be asked, in contrast to retrospective conditions, in which such judgments are required after the relevant period without any prior warning. In three experiments, an attention-sharing method was used. Subjects were asked to control the amount of attention that they devoted to one or the other component of a dual-task paradigm. The first experiment involved word categorization and reproduction of duration. The following experiments, based on signal detection theory, required discrimination of both the duration and the intensity of a single stimulus, in the visual (Experiment 2) or the auditory (Experiment 3) modality. The results indicate that when the attention is directly controlled by the subject, the subjective duration shortens as the amount of attention devoted to the temporal task diminishes. The implications of these results for the possible existence of an internal timer are considered.

Adult↗
PubMed1993

[The use of low doses of intermediate acting muscle relaxants in adenotonsillectomy].

In this study we compared the efficacy of a reduced dose of medium term neuromuscular blocking agents atracurium (0.20 mg/kg) and vecuronium (0.04 mg/kg) in short-term (8-10 min) pediatric surgery. Eighty-four children (ASA I and II) undergoing adenotonsillectomy were selected for this study. Their average age was 56 months (range 30-121 months). We compared intubation conditions and the level of neuromuscular blockade using accelerometry. The induction and maintenance of anesthesia were achieved by anaesthetic gas (halothane first followed by isoflurane). Later on 57 children received vecuronium 0.04 mg/kg (group V) and 27 atracurium 0.20 mg/kg (group A). The latency period was similar in both groups (114.5 +/- 36.1 sec gruppo V vs 100.1 +/- 32.1 sec gruppo A). Intubation was performed in the same period of time (159 +/- 17.4 sec gruppo V vs 156 +/- 20.8 sec gruppo A) and the stimulus was always less than 5% of the baseline values. Intubation was considered excellent in 93% of patients of group V, good in 3.5% and poor in 3.5%. Conversely in patients of group A intubation was considered excellent in 85%, good in 11.5% and poor in 3.5% (n.s.). The neuromuscular recovery, measured by T1 > 5%, was faster in group V (493.6 +/- 154.3 sec gruppo V) than group A (652.6 +/- 210.9 sec gruppo A) (p < 0.001). The TOF ratio during extubation was significantly lower in group A (0.556 +/- 0.177 gruppo A) than in patients of group V (0.789 +/- 0.173 gruppo V) (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoidectomy↗
PubMed1990

Measurement of cutaneous colour and assessment of skin type.

Skin colour was evaluated in summer in 91 Caucasian volunteers by means of a Minolta Chroma Meter CR-200, a colour analyser for measuring the reflective colour of surfaces by the tristimulus system. All the subjects were classified for skin type according to Fitzpatrick and minimal erythema dose determined. The skin colour of the buttock was taken to be the constitutive skin colour, and that of the cheek the facultative skin colour. It was found that the chromaticity of exposed skin was noticeably different from that of unexposed skin, being situated to the right of the latter in the chromaticity diagram. This means that skin that is usually exposed to the sun has a more intense red component, presumably because of increased vascularization. Exposed skin also showed lower reflectance (Y) or lightness (L*) than unexposed skin, probably because of pigmentation. Hence delta Y and delta L* give an approximate idea of the tanning capacity of each subject. delta Y and delta L* of skin types II and III were greater than delta Y and delta L* of skin type IV. This means that, with chronic exposure to sunlight, even fair skin can achieve a reasonable pigmentation. It is concluded that constitutive skin colour is a more meaningful parameter than facultative skin colour in assessing skin type.

Adolescent↗
PubMedDate not supplied

Cutaneous phaeohyphomycosis due to Alternaria tenuissima.

A 50-year-old gardener with a 3-year history of pemphigus vulgaris and steroid-induced diabetes complained of various papulonodular lesions on the left elbow. The lesions had appeared 11 months previously. Skin biopsy showed chronic granulomatous inflammation of the dermis which contained septate hyphae and large spores mainly free. Fragments of the biopsy specimen, cultured on Sabouraud glucose agar without cycloheximide, for 4 days, produced soft white colonies which later turned blackish brown, especially on the underside. On the basis of the microscopic characters of the conidiophores and conidia, Alternaria tenuissima was identified. This phaeohyphomycete has only been isolated previously in two other cases in Italy.

Alternaria↗