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Biomedical subjects

K Mohr

Publications and source records attributed to K Mohr.

99 records · Page 6Linked to original sources
PubMed1975

An absorbable artificial vas deferens for vasovasotomy.

An absorbable artificial vas deferens is being developed in order to improve the relativley poor conception rates of vasovasotomy. The capillary device which is 0.4 mm I.D. by 0.7 mm O.D. and 15 mm long vas made from 3 absorbable polymers: starch, collagen, and a copolyester of lactide and glycolide. Preliminary evaluation of the device was made by implantation in the guinea pig was deferens immediately following vasectomy. Absorption of the starch and the copolyester occurred within 2-4 wks after implantation, whereas collagen required 3 mos and sometimes longer. Gross and histological examination showed little or no adverse effect on the tissues of the vas deferens, epididymes and testes. Active spermatogenesis continued in most cases and sperm count and motility remained essentially unchanged. Breeding studies with males implanted with the device for 5 mos have resulted in 12/13 prrgnancies with starch, 19/19 pregnancies with the copolyester and 9/11 pregnancies with collagen.

Animals↗
PubMed1968

Trophoblast antigenicity demonstrated by altered challenge graft survival.

Adult C57BL/6J male mice received either a primary ectopic transplant or a primary and a challenge ectopic transplant of trophoblast tissue obtained from the ectoplacental cones of 7(1/2)-day-old C3H/HeJ x C3H/HeJ embryos. Gross and histologic examinations of these grafts at 5, 7, and 12 days of growth indicated that the challenge grafts were inhibited in growth; there were a smaller percentage of grossly successful grafts, smaller hemorrhagic reactions, fewer viable cells at all stages of growth, and better host containment of the colony. The evidence indicates that exposure to pure trophoblast alters an animal's subsequent reaction to grafts syngeneic with the original trophoblast and can best be explained as evidence of immunologic sensitization of the host.

Animals↗
PubMedDate not supplied

Differential influence of anionic and cationic charge on the ability of amphiphilic drugs to interact with DPPC-liposomes.

The compounds clofibric acid and chlorphentermine have identical aromatic ring systems, but when charged their side chains are anionic or cationic, respectively. The drugs were applied as tools to investigate whether the interaction of amphiphilic drugs with the zwitterionic dipalmitoyl-phosphatidylcholine (DPPC) depends on the charge of the polar side chain. In suspensions of DPPC-liposomes, the drug-effect on the phase-transition temperature (Tt) was evaluated by means of differential scanning calorimetry. The drug-binding was determined spectrophotometrically. The clofibric acid anion had a much weaker depressing effect on Tt than the chlorphentermine-cation and a considerably lower ability to bind to the DPPC-liposomes. Furthermore, a plot of the effect versus the binding suggested that the clofibric acid-anion had a lower intrinsic activity to reduce Tt compared with the chlorphentermine-cation. In contrast, when the dissociation-equilibrium was shifted towards the uncharged state both drugs were indistinguishable with respect to effect and binding, suggesting that the differences observed with the charged forms could indeed be attributed to the opposite charges. The findings are tentatively explained to result from a different ability of the anionic and the cationic form to reach the hydrophobic interior of the DPPC-bilayer.

1,2-Dipalmitoylphosphatidylcholine↗