PURPOSE: During the course of the development of visual prostheses, subretinal stimulation films were implanted in micropigs in order to prove the feasibility of subretinal electrical stimulation with subsequent cortical response. One aim was to demonstrate that epidural recording of visual evoked potentials is possible in the micropig. METHODS: Film-bound stimulation electrode arrays were placed in the subretinal space of micropigs. This enabled the retina to be stimulated subretinally. Since conventional visual evoked potential (VEP) measuring is virtually impossible in the pig from the neurosurgical point of view, epidural recording electrode arrays were positioned over the visual cortex as permanent electrodes. RESULTS: The feasibility of temporary implantation of film-bound stimulation electrode arrays was successfully demonstrated in the micropig model. On stimulation with monopolar voltage pulses (1000 to 3000 mV), reproducible epidural VEP measurements (5 to 10 micronV) were detected. CONCLUSIONS: The feasibility of subretinal stimulation of the retina was demonstrated in a retinal model that is similar to the human retina. This animal model therefore offers a suitable means of studying the tolerability of stimulation situations in the course of visual prosthesis development.

Animals↗

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[Valves and valve pockets of the thoracic duct: sites of stagnation of neoplastic cells].

The thoracic duct was excised and histologically examined in 53 patients who died due to cancer. 11 specimens showed intraluminal cancer cells without signs of tumor migration through the duct wall. The malignant cells were either unattached in the lumen, caught within the valve pocket or had invaded the valve tissue. These findings add to the importance of lymphotropic cytotoxic agents.

Autopsy↗

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[Polyaneurysmal disease].

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Aneurysm↗

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[Clinical picture and blue test for primary lymphedema of the lower extremities].

The parameters of familial anamnesis, of personal anamnesis, epidemiology and the clinical modifications of details are now so well established that a diagnosis of primary lymphedema can be given with fair certainty, without the aid of complementary examinations. The blue test is not conclusive except when carried out and evaluated by an extremely experienced practitioner; there is no point in using ascendant lymphography, especially as it leads to no particular confirmation of therapy. Microlymphography makes it possible to differentiate hereditary lymphedema better. In the fairly rare descendant forms lymphography is still indicated at the current level of research for iconographical as well as therapeutic reasons.

Adolescent↗

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[Primary lymphedema and pregnancy].

From a retrospective analysis of 15 female patients, it appears that primary lymphedema, reversible at first, tends to become irreversible during successive pregnancies. A remission takes place following the first and second pregnancy, and during a third pregnancy, an irreversible stage is reached.

Adolescent↗

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[A Swiss indication for varicose vein surgery in patients over 60?].

A retrospective investigation into 100 patients operated on after the age of 60 led to the following two conclusions: in 55 p. cent, the motivation for the operation was aesthetic, due to third age vanity; pedestrian activity at retirement age is considerable. The frequent appearance of cramp symptomology of various types prompts us to make a thorough investigation of the arterial circulation of all the older patients. Is there really a Helvetian indication? Certainly not as far as aesthetics are concerned, since this is a general tendency among retired people. But definitely yes when arterial causes of cramps during walking can be excluded.

Aged↗

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[Role of perforating veins in the occurrence of ulcers of the leg, hypodermitis and white atrophy].

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Humans↗

PubMedDate not supplied

[Esthetics in the surgery of varices, especially in the region of the groin].

When dealing with the sapheno-femoral junction, the surgeon has a choice of three possible types of incision: the sub-inguinal incision often results in a badly placed ligature and unaesthetic scarring. The incision in the inguinal hollow allows line scars on thin subjects. The supra-inguinal or high incision allows immediate cicatrization in all subjects. The public hair hides all traces of the scar in this region, significant for aesthetics in phlebology.

Adult↗

PubMedDate not supplied