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Biomedical subjects

L Schneider

Publications and source records attributed to L Schneider.

At least 19 recordsLinked to original sources

Experimental autoimmune nigral damage in guinea pigs.

An animal model of experimental autoimmune nigral damage (EAND) has been developed in guinea pigs by immunization with hybrid dopaminergic cells (MES 23.5). In such animals, loss of 40% of the substantia nigra (SN) neurons and damage to an additional 10% of SN neurons was associated with a 37-43% decrease of tyrosine hydroxylase (TH) activity and a 36% decrease of dopamine (DA) content in the nigral-striatum. Eight of the thirteen animals developed significant hypokinesia. The EAND model suggests that degeneration of dopaminergic neurons in SN can be caused by immune-mediated processes, which may help our understanding of the pathogenesis in Parkinson's disease.

Animals

A single isocenter three-field breast irradiation technique using an empiric simulation and asymmetric collimator.

The treatment of abutting fields presents multiple difficulties, including problems of field overlaps or gaps, complexity of simulation, and the difficulties of daily setup and variation. Multiple techniques have been described for the treatment of the breast/chest wall and supraclavicular nodes using tangents and a matched supraclavicular field. The techniques described have used collimator angles, couch angles, and/or corner blocks in an attempt to match these fields with no overlap or gap. Some of these techniques required complex calculations or treatment devices to achieve a geometric match between fields. We describe a technique for treatment of breast and supraclavicular nodes that uses a single isocenter and requires asymmetric collimator jaws to give half-blocked fields. The simulation and setup are done empirically, with no complex calculations required. The daily setup and treatment can be done rapidly and reliably, with no extra equipment required. Custom blocks may be used to conform to the chest wall contour and decrease the amount of lung in the treatment fields.

Breast Neoplasms

Perceptual and conceptual cueing in implicit and explicit retrieval.

Subjects saw or heard words in a list (e.g. limerick) and then took two successive tests. The first was a yes/no recognition test in which auditory/visual modality of test words was manipulated orthogonally to the study modality. The second test varied with experimental conditions: subjects produced words to either perceptual (fragment) cues (l- -e-ick) or conceptual cues (What name is given to a lighthearted five-line poem?), under either explicit or implicit retrieval instructions. The major findings were: (a) that regardless of the type of retrieval cue (perceptual or conceptual) the degree of dependency between recognition and cued recall was greater than that between recognition and implicit retrieval; and (b) that modality shifts adversely affected perceptually cued explicit and implicit retrieval, whereas they had no effect either on conceptually cued retrieval or on recognition. These results suggest that the memory system subserving, and the processes involved in, conceptual priming differ from those underlying recognition and perceptual priming.

Analysis of Variance

[Meniscal suture through the arthroscopic route. 3 years' experience].

Meniscal suture using an arthroscopic route is a safe method with an extremely low percentage of failure and complications. The two techniques most commonly used (from inside to outside and from outside to inside) are similar. The introduction of the needle as far as possible from neurovascular structures makes the outside-inside technique less risky. In the event of associated rupture of LCA ligament reconstruction must always be performed as well as the repair of the meniscus. Isokinetic evaluation has confirmed the rapidity of functional recovery times.

Adult

[Halo-vest in the treatment of fractures of the upper cervical spine. Fractures of the epistropheus].

The authors examine the use of a halo-vest brace in the treatment of fractures of the upper cervical spine. This brace forms a valid alternative to the classic plaster cast in that it is easily positioned, well tolerated by the patient and has a high restrictive capacity for the centre of the fracture. In the cases treated by the authors no complications were reported during treatment, and consolidation time was shortened by 30 days in relation to traditional plaster cast treatment.

Axis, Cervical Vertebra

Thymopentin therapy reduces the clinical severity of atopic dermatitis.

One hundred patients with moderate to severe atopic dermatitis were entered into a two-center, double-blind trial. Patients were randomized to receive either thymopentin (Timunox, n = 48) or placebo (n = 52), administered as daily subcutaneous injections for 6 weeks. Clinical extent of disease and severity parameters were measured at baseline and at regular time intervals during the study. Both the placebo- and thymopentin-treated groups demonstrated a progressive and statistically significant (p less than 0.001) decline in the overall severity of their disease, but reduction in the clinical severity score was higher in the thymopentin-treated group and statistically significant (p = 0.04) in comparison with the placebo-treated group after 6 weeks of treatment. Of the individual symptoms comprising the total severity score, pruritus (p = 0.02) and erythema (p = 0.04) were reduced significantly when thymopentin therapy was compared to placebo therapy. In addition, both the extent of body involvement and severity index (a combined severity/extent index) were significantly reduced after 6 weeks in the thymopentin-treated group in comparison to the placebo-treated group (p = 0.04). There were no serious adverse experiences in either treatment group. We conclude that treatment with thymopentin is safe and offers significant therapeutic promise for atopic dermatitis.

Adolescent

Vasovagal syncope: diagnostic role of head-up tilt test in patients with positive ocular compression test.

We investigated the relative merits of the ocular compression test and the head-up tilt test to aid differentiation of syncope and seizures in young patients. Sixteen patients (10 males and 6 females) with a mean age of 14 +/- 4.7 (SD) years (range 7-22 years) underwent graded head-up tilt (15 degrees, 30 degrees, and 45 degrees for 2 minutes each, then 60 degrees for 20 minutes) following positive ocular compression testing defined as precipitation of asystole for at least 3 seconds (mean 5 seconds +/- 2 seconds, range 3-12 seconds). Each patient presented with recurrent unexplained loss of consciousness (mean number of episodes 30 +/- 45, mean duration of illness 52 +/- 40 months), and seven patients were receiving anticonvulsant medications, three of these had normal EEGs. Eleven patients (69%) developed vasovagal syncope during head-up tilt, reproducing their clinical episodes (systolic blood pressure decreased from 105 +/- 10 mmHg to 84 +/- 13 mmHg, diastolic blood pressure from 75 +/- 9 to 22 +/- 25 mmHg, and heart rate from 89 +/- 13 beats/min to 37 +/- 20 beats/min). Asystole occurred in two patients during vasovagal syncope lasting 11 seconds in one and 16 seconds in the other, and, it was associated with myoclonic movements in both (convulsive syncope). Based on these findings, and given the perceived potential hazards of the ocular compression test, the head-up tilt test may be a safer procedure that adds useful information to the diagnostic evaluation of these patients.

Adolescent

Childhood antecedents of antisocial behavior: parental alcoholism and physical abusiveness.

Hierarchical logistic regression was used to assess the independent and interactive effects of paternal alcoholism and physical child abuse on antisocial behavior in young adult men. Men with alcoholic fathers (N = 131) did not report or exhibit more antisocial behavior than comparison subjects (N = 70). Men with physical abuse histories, however, reported more aggressive and antisocial behaviors during a clinical interview and were rated by a clinical interviewer as more likely to act out aggression. Arrest records did not distinguish the groups. There was no evidence that paternal alcoholism and childhood victimization interacted to increase the risk of antisocial behavior.

Acting Out

Fluvoxamine in the treatment of tricyclic-resistant depression.

Following an initial double-blind, randomized, parallel treatment group comparison of fluvoxamine, desipramine, and placebo in 89 outpatients with major depression at two centers, double-blind crossover to fluvoxamine was offered to 13 of 22 desipramine-treated completers of the initial phase who were considered failures on desipramine. Twelve elected to cross over to blinded fluvoxamine, and eleven continued on fluvoxamine for at least eight weeks. Nine of these eleven improved, and overall there was a statistically significant decrease in average Hamilton Depression Scores, from 24 to 13, for these fluvoxamine-treated desipramine-resistant patients.

Adult

[Biarticular endoprostheses of the hip. 2 years of experience].

After briefly illustrating indications and biomechanical concepts of biarticular endoprostheses of the hip in the treatment of medial fractures of the femoral neck, a personal series from December 1985 to March 1988 is presented. 55 of 82 operated patients were followed up on the basis of purely clinical criteria, particular attention being paid to general preoperative conditions, the recovery of function and the rate of postoperative mortality. In conclusion, it is recalled that prognosis in fractures of the femoral neck is severe for generally gerontological reasons and the usefulness of biarticular endoprosthesis in the prevention of cotyloid wear and tear is underlined.

Aged

[Initial experience with the Ilizarov apparatus in orthopedic and traumatological pathology].

Personal experience of 4 years with the use of Ilizarov's apparatus is reported. The apparatus has been utilised on a routine basis in the treatment of complex fractures, in pseudarthrosis and in hypometrias. On the whole, the results obtained were positive, confirming the value of the apparatus and its ductility in the treatment of complex lesions of the skeleton.

Adolescent