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Biomedical subjects

G Pellizzer

Publications and source records attributed to G Pellizzer.

33 records · Page 2Linked to original sources
PubMed1995

Amphotericin B as primary therapy for cryptococcosis in patients with AIDS: reliability of relatively high doses administered over a relatively short period.

Thirty-one consecutive AIDS patients with cryptococcal disease were enrolled in a study of the efficacy and safety of short-course primary treatment with a relatively high dose of amphotericin B (1 mg/[kg.d] for 14 days); 26 patients also received flucytosine (100-150 mg/[kg.d], given either intravenously or orally). Twenty-five patients had cryptococcal meningitis confirmed by culture, three had presumed cryptococcal meningitis, and three had disseminated extrameningeal cryptococcosis. After successful primary treatment, all patients were given oral itraconazole or fluconazole as suppressive therapy, and their lifelong clinical and mycologic follow-up was planned. Successful primary therapy was defined as the resolution of symptoms and the documentation of negative cultures of cerebrospinal fluid and/or blood 2 months after the initial diagnosis. Therapy was successful in 29 (93.5%) of all 31 cases and in 26 (92.8%) of the 28 cases of culture-proven or presumed cryptococcal meningitis. Nephrotoxicity developed as a result of amphotericin B administration in seven cases; this adverse reaction required a reduction of the dose in two cases and the discontinuation of therapy in five. No deaths due to cryptococcosis were documented during primary therapy. Treatment failed in two cases. During a mean observation period of 10.7 months, three relapses of the underlying infection occurred. Our results indicate that an aggressive approach to the primary treatment of cryptococcosis in AIDS patients, with the administration of a relatively high dose of amphotericin B for a relatively short period, is effective and well tolerated.

AIDS-Related Opportunistic Infections↗
PubMed1994

Serological survey of hepatitis B infection in Tanzania.

In 1992, the prevalence of hepatitis B virus (HBV) markers was evaluated in 1004 subjects aged one to 76 years living in urban and rural areas in Tanzania. The overall prevalence rates of hepatitis B surface antigen (HBsAg) and of any HBV marker were 4.4% and 37.0%, respectively. No statistically significant difference by sex was found. The HBsAg prevalence among pregnant women was 4.3% (20/463). The proportion of HBeAg positive among HBsAg positive pregnant women was 10% (2/20). The HBsAg age-specific prevalence was 2.1% in the 1-5 year age-group; peak prevalence (12.1%) occurred in the 6-15 year age-group. Markers of HBV infection were 4.1% by age five years; they increased with advancing age (P < 0.01). Subjects residing in urban areas had statistically significant higher HBV exposure than those residing in rural areas (43.9% vs 27.4%, P < 0.01). Subjects belonging to the largest family size (seven or more members) showed increasing risk (OR 2.9; 95% CI = 1.96-4.28) of HBV exposure. Because maternal HBV transmission early in life appears to be of minor impact and children are mostly infected later in infancy, HBV vaccination at birth is not indicated, while vaccination of all infants at 2-3 months of age with other paediatric vaccinations is the first priority.

Adolescent↗
PubMed1994

Mediterranean visceral leishmaniasis in pregnancy.

Visceral leishmaniasis (VL) in pregnancy is rare in Mediterranean countries. We report here 2 cases of VL in pregnant women who acquired the infection in Italy. In the first case, the disease was diagnosed and treated with liposomal amphotericin B during the pregnancy. In the second case, diagnosis was established and treatment with meglumine antimoniate both undertaken shortly after delivery. The 2 infants were followed clinically and serologically for 8-9 months after birth, but no evidence of congenital VL was observed.

Adult↗
PubMed1993

Common processing constraints for visuomotor and visual mental rotations.

Naive human subjects were tested in three different tasks: (1) a visuomotor mental rotation task, in which the subjects were instructed to move a cursor at a given angle from a stimulus direction; (2) a visual mental rotation task, in which the subjects had to decide whether a displayed letter was normal or mirror image regardless of its orientation in the plane of presentation; and (3) a visuomotor memory scanning task, in which a list of two to five stimuli directions were presented sequentially and then one of the stimuli (test stimulus), except the last one, was presented again. Subjects were instructed to move a cursor in the direction of the stimulus that followed the test stimulus in the previous sequence. The processing rate of each subject in each task was estimated using the linear relation between the response time and the angle (mental rotation tasks) or the list length (memory scanning task). We found that the processing rates in the mental rotation tasks were significantly correlated but that neither correlated significantly with the processing rate in the memory scanning task. These results suggest that visuomotor and visual mental rotations share common processing constraints that cannot be ascribed to general mental processing performances.

Cognition↗
PubMed1993

Motor cortical activity preceding a memorized movement trajectory with an orthogonal bend.

Two monkeys were trained to make an arm movement with an orthogonal bend, first up and then to the left ([symbol: see text]), following a waiting period. They held a two-dimensional manipulandum over a spot of light at the center of a planar working surface. When this light went off, the animals were required to hold the manipulandum there for 600-700 ms and then move the handle up and to the left to receive a liquid reward. There were no external signals concerning the "go" time or the trajectory of the movement. It was hypothesized that during that period signs of directional processing relating to the upcoming movement would be identified in the motor cortex. Following 20 trials of the memorized movement trajectory, 40 trials of visually triggered movements in radially arranged directions were performed. The activity of 137 single cells in the motor cortex was recorded extracellularly during performance of the task. It was found that 62.8% of the cells changed activity during the memorized waiting period. During the waiting period, the population vector (Georgopoulos et al. 1983, 1984) began to grow approximately 130 ms after the center light was turned off; it pointed first in the direction of the second part of the memorized movement (<--) and then rotated clockwise towards the direction of the initial part of the movement (increases). These findings indicate processing of directional information during the waiting period preceding the memorized movement. This conclusion was supported by the results of experiments in ten human subjects, who performed the same memorized movement ([symbol: see text]). In 10% of the trials a visual stimulus was shown in radially arranged directions in which the subjects had to move; this stimulus was shown at 0, 200, and 400 ms from the time the center light was turned off. We found that as the interval increased the reaction time shortened for the visual stimulus that was in the same direction as the upward component of the memorized movement.

Animals↗
PubMed1993

Regional and systemic prophylaxis with teicoplanin in monolateral and bilateral total knee replacement procedures: study of pharmacokinetics and tissue penetration.

Twenty-four patients undergoing monolateral or bilateral total knee replacement (TKR) procedures were randomized to receive teicoplanin (T) either systemically or regionally. Subjects scheduled for systemic prophylaxis and undergoing monolateral (six patients) or bilateral (five patients) TKR received a single 800-mg dose of T in 100 ml of saline as a 5-min infusion into a forearm vein 2.5 h before surgery. For regional prophylaxis, patients undergoing monolateral surgery (eight subjects) received 400 mg of T in 100 ml of saline as a 5-min infusion into a foot vein of the leg to be operated on immediately after the tourniquet was inflated. For the five patients scheduled for bilateral operation and regional prophylaxis, the administration of T was also repeated for the second knee operation. The tourniquet, as the standard TKR surgical technique, was inflated to 400 mm Hg (c. 50 kPa) in all 24 patients immediately before the beginning of surgery and kept in place for the duration of the operation. Samples of serum, bone, skin, synovia, and subcutaneous tissue were collected at timed intervals during surgery. They were microbiologically assayed for T by using Bacillus subtilis as the test organism. Overall, the mean T concentrations obtained with regional route prophylaxis were found to be 2 to 10 times higher than those achieved following systemic prophylaxis. Moreover, peak levels in different tissues after regional prophylaxis were significantly higher (P < 0.05). None of the patients experienced adverse effects due to regional or systemic T administration; no prosthetic or wound infections were observed in the follow-up period (from 12 to 26 months).

Aged↗
PubMed1992

Three-dimensional drawings in isometric conditions: planar segmentation of force trajectory.

Normal human subjects grasped an isometric handle with an unrestrained, pronated hand. They were asked to exert forces continuously to draw lemniscates (figure eights) in specified or self-chosen planes and in the presence or absence of a three-dimensional visual feedback cursor and a visual template. In every condition, the mean plane orientation in the force space differed appreciably between the two loops of the figure, as described previously by Soechting and Terzuolo (1987a) for free drawing arm movements. These findings suggest that the planar segmentation of the motor trajectory is not a consequence of joint motion but arises from central constraints related to the production of motor trajectory in space.

Feedback↗
PubMed1992

Three-dimensional drawings in isometric conditions: relation between geometry and kinematics.

Normal human subjects grasped a 3-D isometric handle with an otherwise unrestrained, pronated hand and exerted forces continuously to draw circles, ellipses and lemniscates (figure-eights) in specified planes in the presence or absence of a 3-D visual force-feedback cursor and a visual template. Under any of these conditions and in all subjects, a significant positive correlation was observed between the instantaneous curvature and angular velocity, and between the instantaneous radius of curvature and tangential velocity; that is, when the force trajectory was most curved, the tangential velocity was lowest. This finding is similar to that obtained by Viviani and Terzuolo (1982) for 2-D drawing arm movements and supports the notion that central constraints give rise to the relation between geometric and kinematic parameters of the trajectory.

Female↗
PubMed1992

Familial outbreak of agricultural anthrax in an area of northern Italy.

Three cases of cutaneous anthrax are reported which occurred in a farming family in northern Italy. Epidemiological studies revealed contact with an infected cow (delivery of a stillborn fetus and slaughter). The cow was slaughtered soon after the delivery; cultures of carcass specimens yielded growth of Bacillus anthracis. The origin of the animal infection was not known. Serum samples were obtained from all 11 members of the family group and randomly from 10 of the 75 cows on the farm, which appeared to be in good health. Tests for antibodies against protective antigen and lethal factor using EIA and Western blot techniques were positive in three subjects (in paired sera) with cutaneous anthrax and in one subject who neither had had direct contact with the infected cow nor showed any sign of anthrax.

Adult↗
PubMed1990

Expressed emotion and first-admission schizophrenia. Nine-month follow-up in a French cultural environment.

A study of 36 French-speaking families in Geneva identified 66% of high-EE household. At nine-month follow-up, the relapse rate for the high-EE group (33%) was significantly higher than for the low-EE group (0%). These results seem to confirm the relevance of EE as predictor of relapse. However, in our sample, it appears that one component of EE, critical comments, was principally responsible for the prognostic validity.

Adolescent↗
PubMed1988

Family expressed emotion and outcome of schizophrenics: a study in a French cultural environment.

This is the first attempt in a french cultural environment to relate family characteristics and expressed emotion to clinical course of schizophrenics. patients were studied during a two year period after their first or second hospital stay. Critical comments on subcategory of classical expressed emotion is associated with relapse, rehospitalization and work capacity but not with a broad measure of social activity.

Cultural Characteristics↗
PubMedDate not supplied

Molecular heterogeneity and new subtypes of HCV genotype 4.

The subtype distribution of HCV genotype 4 was studied in two different African countries, Egypt and Tanzania. The HCV isolates were obtained from epidemiological studies involving, respectively, 135 hepatopatic patients and 1043 pregnant women and outpatients. Sequence comparison and phylogenetic analysis of the NS5b genome region (nt 8327-8499) were performed. Fourteen out of 18 isolates from Egypt, but only 3 out of 6 isolates from Tanzania clustered in the same branch of subtype 4a. Three new proposed subtypes have been identified. The first includes 1 isolate from Egypt (EGY15); the second, 2 isolates from Egypt (EGY193 and EGY44) and 2 isolates from Tanzania (D776, D61); and the third, 1 isolate from Egypt (EGY47) and 1 isolate from Tanzania (D70). These isolates cluster in branches different from any other, corresponding to a known subtype of genotype 4. In conclusion, remarkable genetic heterogeneity has been found among genotype 4 isolates simultaneously circulating in a restricted area. This was particularly observed in the study performed in Tanzania. Potential concern about the sensitivity of diagnostic assays and possible implications in the development of future vaccines have been stressed.

Egypt↗
PubMedDate not supplied

Neural coding of finger and wrist movements.

Previous work (Schieber and Hibbard, 1993) has shown that single motor cortical neurons do not discharge specifically for a particular flexion-extension finger movement but instead are active with movements of different fingers. In addition, neuronal populations active with movements of different fingers overlap extensively in their spatial locations in the motor cortex. These data suggested that control of any finger movement utilizes a distributed population of neurons. In this study we applied the neuronal population vector analysis (Georgopoulos et al., 1983) to these same data to determine (1) whether single cells are tuned in an abstract, three-dimensional (3D) instructed finger and wrist movement space with hand-like geometry and (2) whether the neuronal population encodes specific finger movements. We found that the activity of 132/176 (75%) motor cortical neurons related to finger movements was indeed tuned in this space. Moreover, the population vector computed in this space predicted well the instructed finger movement. Thus, although single neurons may be related to several disparate finger movements, and neurons related to different finger movements are intermingled throughout the hand area of the motor cortex, the neuronal population activity does specify particular finger movements.

Finger Joint↗