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Biomedical subjects

C Beck

Publications and source records attributed to C Beck.

329 records · Page 19Linked to original sources
PubMedDate not supplied

Monocytogenic endothelialization in dacron grafts. Experimental studies on rats.

The cytogenetic relationship between cells of the hematopoetic system and prosthesis lining cells is still not known. The purpose of this experimental study was to determine to what degree blood monocytes may be transformed into those cells which line the inner surface of vascular grafts. Immunological identical rats (donors = 25) were pretreated with a total dose of 150 micrograms C 3H-thymidine. In 25 recipient rats of the same strain the infrarenal aorta had been replaced by a vascular graft of dacron (1.8 mm theta) by using microsurgical techniques. Arteriovenous cross-transfusion was installed in pairs of the donor and recipient animals allowing for mixing the total blood volumes of both many times. Following sacrifice of the recipients the grafts and the area of anastomosis were studied autoradiographically. In all animals labelled monocytes were found in the graft wall with a marking index (MI) running between 1.5% to 5.5%. The marking index of the prosthesis lining cells was 1.9% to 3.4%. In 6 animals the anastomotic area was labelled and the MI run from 1% to 7.5%. With this new experimental model we ascertained that blood monocytes have capability of transformation: our results would indicate the hematogenic origin of new endothelial cells on prosthetic vascular surface by transformation of blood monocytes. This appears to apply to the prosthetic wall as well as the inner surface lining cells and the neighbourhood of the anastomotic area.

Animals↗
PubMedDate not supplied

[A study of damaged acoustic biopotentials in guinea pigs following exposure to white noise].

62 guinea-pigs were treated twice exposed to white noise, 105 dB SPL, 20 to 20 000 cps for 40 minutes with a break of 24 hours in between. The cochlear microphonics (CM), the compound action potentials of the acoustic nerve (NAP) and the slow evoked potentials (SEP) were recorded. There were different degrees of damage to be seen in the acoustic biopotentials. The CM showed little damages only whereas the compound action potentials of the hearing nerve showed significant impairments in excitation and in adaptation. In the SEP excitation was decreased. From this, we may conclude that the CM must not be the only criterion for judging damages in the acoustic system after acoustic trauma. Furthermore we see that the central acoustic pathway is capable to compensate peripheric hearing damages within a short time. An additional exposure to noise does not necessarily add or cumulate the degrees of damage.

Action Potentials↗