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Biomedical subjects

H Schott

Publications and source records attributed to H Schott.

162 records · Page 9Linked to original sources

Mandibular reconstruction using a free vascularised osteocutaneous flap from the internal condyle of the femur.

The authors present a preliminary report of a new microsurgical mandibular reconstruction procedure using a segment of the internal condyle of the femur as a free vascularised bone graft. It is possible to harvest a compound flap including a bony segment measuring 8 X 1.5 X 1.5 cm and a cutaneous saphenous flap with its nutrient pedicle arising from the descending genicular artery and vein. This surgical procedure provides a good cortico-cancellous bony segment and a separate skin flap. Dissection of the flap is sometimes difficult due to the inconsistency of its vascular anatomy; the donor site is left with minimal morbidity but, because of weakening of the femur, our patients are instructed not to return to full weight-bearing before the sixth postoperative week. We consider segmental reconstruction of the mandibular body to be one of the best indications for the flap.

Adult↗

Synthesis, in vitro anti-HIV and anti-hepatitis B activities and pharmacokinetic properties of amphiphilic heterodinucleoside phosphates containing ddC and AZT.

Amphiphilic heterodinucleoside phosphates containing AZT and ddC as antiviral monomer were synthesized according to the hydrogenphosphonate method and evaluated in vitro against HIV. dT-N4-pamddC was the most active (IC50 = 40 microM, EC50 = 80 nM) and least toxic (TI = 524) dimer and it exhibited also strong antiviral effects against eight AZT-resistant HIV strains. The ddC-containing heterodimers additionally inhibited HBV replication by 50-80% at 50 microM in Hep G2 2.2.15 cells.

Anti-HIV Agents↗

The antitumour effect of lipophilic derivatives of 5-fluoro-2'-deoxyuridine incorporated into liposomes.

Lipophilic prodrugs of 5-fluoro-2'-deoxyuridine (FUdR), namely 5'-O-palmitoyl-5-fluoro-2'-deoxyuridine (5'-O-palm-FUdR) and 3',5'-O-dipalmitoyl-5-fluoro-2'-deoxyuridine (3',5'-O-dipalm-FUdR), were incorporated into bilayer liposomes. Prodrug incorporation into positively charged liposomes was quantitative and stable, homogeneous bilayer vesicles were obtained. The maximal amounts of prodrug incorporation are 200 micrograms for 5'-O-palm-FUdR and 90 micrograms for 3',5'-O-dipalm-FUdR per mg egg phosphatidylcholine as matrix lipid. The prodrug-liposome preparations were tested in vivo against mammary carcinoma 13/C, Lewis lung carcinoma and L1210 leukaemia and compared to the cytostatic activity of free FUdR and of the prodrugs dissolved in peanut oil. Intraperitoneally administered prodrugs either incorporated into liposomes or dissolved in peanut oil inhibited tumour growth in all animals. The comparison of the doses required for tumour growth inhibition showed that both prodrugs were active at concentrations 20-75 times lower as compared to unmodified FUdR. However, due to the increased toxicity of the prodrug-liposome preparations, the therapeutic index of the parent drug FUdR could not be improved. The cytostatic effect of the prodrug preparations may be explained by altered pharmacokinetic properties of the FUdR derivatives and the additional sustained release action the liposomes are providing. A further increase of the antitumour activity may be obtained by the attachment of tumour-specific antibodies to the surface of such prodrug-containing liposomes.

Animals↗