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Biomedical subjects

S Vanneste

Publications and source records attributed to S Vanneste.

7 recordsLinked to original sources
PubMed2004

An easy and versatile embedding method for transverse sections.

In several research areas, transverse sections are indispensable for studying structural aspects of specimens. However, the oriented embedding of small cylindrical samples can become problematic, especially when transverse sections at right angles to the main axis of the object are desired. Here, we describe an easy and low-cost technique for oriented embedding of small (psi < 500 micro m) as well as of larger specimens (psi > 500 micro m). The usefulness of the technique is demonstrated for roots and stamens of Arabidopsis thaliana and for adventitious roots of Asplenium demerkense, as examples of small and larger cylindrical samples, respectively. Furthermore, several types of resin (glycol methacrylate, epoxy and acrylic resins) were successfully tested, showing the applicability of the technique for light and electron microscopy and for immunolocalizations. In conclusion, the principle of the technique can be extended to several resins and a wide variety of specimen types, such as stems, leaves and textile fibres. The originality of the technique lies in its simplicity combined with its high efficiency to produce well-oriented transverse sections.

Arabidopsis↗
PubMed1994

Polyarteritis nodosa type vasculitis in a patient with familial Mediterranean fever treated with cyclosporin A.

Patients with amyloidosis secondary to familial Mediterranean fever (FMF) are known to tolerate cyclosporin A poorly. We report a case of severe cyclosporin toxicity in a patient with FMF amyloidosis who underwent kidney transplantation. The clinical syndrome consisted of severe gastrointestinal, neuromuscular, and psychiatric disturbances. Histological examination of the transplanted kidney revealed vasculitis of the polyarteritis nodosa type. We hypothesize that FMF patients are more vulnerable to the acute vascular toxicity of cyclosporin due to defective inhibition of complement activation, leading to a widespread vasculitis of the polyarteritis nodosa type.

Adult↗
PubMed1991

Occult tuberculous postpneumonectomy space empyema four years after lung resection.

We describe a patient in whom a tuberculous postpneumonectomy empyema developed 4 years after resection for lung cancer. The clinical presentation was dominated by non-specific constitutional symptoms, without any chest complaints. A computed tomographic scan of the chest suggested inflammation in the postpneumonectomy space. Ultimately Mycobacterium tuberculosis was cultured from material aspirated by needle thoracocentesis. To our knowledge this is the first report of a tuberculous postpneumonectomy empyema complicating resection for cancer.

Aged↗
PubMedDate not supplied

Temporal control of rhythmic performance: a comparison between young and old adults.

Young (20-30-year-old) and older (60-76-year-old) adults were tested on two measures of rhythmic performance. The first involved tapping at the subject's own preferred rate, a measure of so-called internal tempo. Over five sessions of testing, tapping rates were consistently and significantly slower on average in the older subjects than the younger ones, but rates were not relatively more variable in older subjects (i.e., coefficients of variation, standard deviation/mean, did not differ between the older and young people). In addition, both old and younger subjects performed on a synchronized-tapping and continuation task of the type used by Wing and Kristofferson (1973, Perception and Psychophysics, 14, 3-12). Target interresponse times were 300, 400, 500, 600, and 700 ms, and in all cases interresponse intervals produced by both the old and young adults matched the target times very closely. Wing and Kristofferson's analytical procedure was used to decompose tapping variance into that attributable to timing processes and that resulting from motor implementation of the timing signal. Both sorts of variance increased with increasing target interresponse time (with timer variance increasing most markedly), but no difference was found in either type of variance in comparisons between the old and younger subjects. If the internal tempo measure directly reflects the speed of internal timing processes, the data suggest that such processes are slower, but not relatively more variable, in older than younger subjects (consistent with some previous evidence and speculation), but that the calibration of performance forced by the synchronization task will make such an age-related difference in "internal clock speed" unobservable on synchronized-tapping tasks.

Adult↗
PubMedDate not supplied

Timing in aging: the role of attention.

This paper questions the issue of attentional capacity in changes in time processing with aging. Performances of young and old subjects were compared in a task involving an attentional sharing between three concurrent estimations of durations (6, 8, or 10 s). Depending upon the experimental condition, the subjects were instructed to simultaneously focus their attention onto one, two, or three target stimuli. The results showed that increased difficulty of the task, that is the increased number of concurrent temporal targets to monitor at a time, led to a greater disruption of timing performance in elderly people than in young adults. Temporal judgments of elderly were less accurate and more variable than those of young adults in the attentional sharing conditions (two or three target durations). The greater sensitivity to interference effects observed in the elderly is discussed in terms of age-related reduction of attentional resources and working-memory deficits.

Adolescent↗