[Microsurgical thumb replantation following traumatic amputation: preliminary results in Hanoi, Vietnam]. / Daumenreplantation nach traumatischer Amputation : Erste Ergebnisse in Hanoi, Vietnam.

INTRODUCTION: Replantation using microsurgical techniques is a fairly new procedure in Vietnam. We reviewed and evaluated our 7-year results of thumb replantation in Vietnamese patients following traumatic thumb amputation. MATERIAL AND METHODS: Traumatic thumb amputations between September 1999 and July 2006 were reexamined and evaluated. Postoperative functional results were evaluated based on four main criteria: 1) the patient's subjective attitude regarding the replanted thumb, 2) the degree of mobility of the replanted thumb compared with its counterpart, 3) the level of sensitivity of the replanted thumb, and 4) the objective ability to perform daily tasks. RESULTS: A total of 26 patients were documented. The duration of follow-up averaged 22 months (range 6-72 months). The success rate of replantation was 81%. A rating of either "good" or "very good" was obtained for 81% of the replanted thumbs. DISCUSSION: Vascular thrombosis was the cause of all failures. Proper debridement, standardized microvascular techniques, timely detection of thrombosis formation, and reoperation using vein grafts play a decisive role in the final success.

Comparison of experimental microvascular end-to-end anastomosis via VCS-Clips versus conventional suture technique in an animal model.

In this experimental study on 96 CD rats, microvascular end-to-end anastomoses created via suture or alternatively by means of a VCS-Clip-Application-System, were compared. The aorta abdominalis of the animals, with a diameter of 1.5 +/- 0.2 mm, was experimentally dissected, and the free ends of the vessel then anastomosed. The results were evaluated using sonography, microangiography, histologic examination, and vascular imprints. Postoperative examination was carried out after 1, 3, 7, 14, or 30 days. Major advantages of the VCS-Clip technique over suturing were that it was easy to learn, significantly faster to perform (execution of anastomosis 10.9 +/- 2.6 min versus 19.4 +/- 5.0 min), and produced significantly more favorable histologic results in terms of less inflammatory response, foreign body reaction, necrosis of the tunica media, hyperplasia of the intima, and thrombosis of the vessel lumen. The main disadvantage of the clip technique was a significantly higher rate of stenoses (15.8 +/- 6.0 versus 4.1 +/- 6.6 percent).

[Experimental investigation of neovascularisation in large prefabricated flaps after arteriovenous pedicle implantation]. / Experimentelle Untersuchung der Neovaskularisation in grossen präfabrizierten Gewebelappen nach arteriovenöser Gefässstielimplantation.

The principle of prefabricated flaps is based on the transformation of a formerly random-pattern vascularized flap, through implantation of a vascular pedicle, into a newly neovascularized axial flap, which can be transferred after a period of neovascularisation from the prepared donor site to the recipient site by using microvascular techniques. In 30 Chinchilla Bastard rabbits weighing from 3700 to 4200 g, a skeletonized arteriovenous pedicle with distal ligation harvested from the femoral and saphena magna artery and vein was implanted beneath an 8 x 15 cm abdominal skin flap to investigate the neovascularisation process in the flap over the course of time. In order to prevent neovascularisation occurring from the underlying vascular bed into the flap, a silicon sheet measuring 8 x 15 cm x 0.25 mm was placed and fixed on the abdominal wall. Flap vitality and neovascularisation process in prefabricated flaps were evaluated by macroscopic observation, blood analysis, selective microangiography, histology and scintigraphy at the various time intervals of 4, 8, 12, 16 and 20 days. The study results showed that newly formed vessels sprouting from the implanted pedicle were seen four days after pedicle implantation. With the retention time of pedicle in the flaps, they continued to grow, became meander and more dense. Respective connections between newly formed vessels and the originally available vasculature of the abdominal flap were markedly observed in the 12- and 16-day groups. Twenty days after prefabrication, the abdominal flap was completely perfused by the blood flow supplied from the newly implanted arteriovenous pedicle through newly formed vessels arising from the implanted pedicle and their rich vascular communications. The neovascularisation in the prefabricated flap consisted of the implanted pedicle, newly formed vessels, the originally available vasculature and their vascular connections. In comparison to the control group (the quantification was determined of 100 %), the vessel quantity in the prefabricated flap of the 20-day group had increased to 98.7 %. As a pre-clinical test, prefabricated flaps through arteriovenous pedicle implantation with special advantages can be a new useful method in plastic and reconstructive surgery.

[Information exchange via internet--possibilities, limits, future]. / Informationsaustausch via Internet--Möglichkeiten, Grenzen, Zukunft.

Today, the exchange of information in the Internet is dominated by the WWW and e-mail. Discussion groups like mailing lists and newsgroups also permit communication in groups. Information retrieval becomes a crucial challenge in using the Internet. In the field of medicine, three more aspects are of special importance: privacy, legal requirements, and the necessity of transferring large amounts of data. For these problems, today's Internet doesn't provide a sufficient solution yet. Future developments will not only improve the existing services, but also lead to fundamental changes in the transfer technologies: Safer data transfer is to be ensured by new encrypting software together with the planned transfer protocol IPv6. Introducing the new transfer mode ATM will lead to better and resource saving transmission. Computer, telephone and TV networks will grow together, resulting in convergence of media.

[Neovascularization of pre-formed tissue flaps in relation to arteriovenous blood flow of the implanted vascular pedicle. Experimental study in the rabbit]. / Die Neovaskularisation im präformierten Gewebelappen in Abhängigkeit vom arteriovenösen Blutfluss des implantierten Gefässstieles. Experimentelle Untersuchung am Kaninchen.

In 45 Chinchilla-Bastard rabbits, a skeletonised arterio-venous pedicle was implanted on the subsurface of a 15 x 8 cm abdominal skinflap to create a neovascularised axial prefabricated flap. In order to evaluate the potency of neovascularisation in relation to the blood flow of the pedicle, we compared minimal blood flow by distal ligation (model 1) with maximal blood flow by distal microvascular arteriovenous shunt anastomoses (model 2) of the implanted vascular pedicle. The results show that 8 and 12 days after pedicle implantation, tissue flap perfusion in model 2 is significantly earlier and better in comparison to model 1.

Comparative pharmacokinetics of two new steroidal estrogens and ethinylestradiol in postmenopausal women.

It was the aim of the study to compare the pharmacokinetic properties of the two new estrogens, ZK 136295 and ZK 115194, with those of ethinylestradiol (EE2) after single intravenous (60 micrograms) and oral (120 and 240 micrograms) administration in 54 postmenopausal women. In particular, our objective was to examine whether one or both compounds were characterized by an improved oral bioavailability with less inter-subject variability than EE2. Drug serum concentrations were determined using specific radioimmunoassays for EE2 and ZK 136295, and a GC/MS/MS-method for ZK 115194. Following i.v. administration of the new estrogens and of EE2, the drugs were rapidly distributed in the body. The mean terminal half-lives were calculated to be 12.3 +/- 12.4, 28.7 +/- 9.6, and 26.1 +/- 11.1 h for ZK 136295, ZK 115194, and EE2 respectively. After oral administration of 120 micrograms, the absolute bioavailability was calculated to be about 40% for ZK 136295 as well as for EE2 with a high inter-individual variation (variation coefficient: 44 and 67%). By doubling the dose, the systemic availability increased dose-dependently for both drugs to about 70% with the same high inter-individual variation. Following single oral administration of 240 micrograms ZK 115194, the absolute bioavailability amounted to 33 +/- 19%. The present study clearly revealed that although the two new estrogens differed considerably in their pharmacokinetic behavior, they demonstrated a reduced and highly variable systemic availability similar to that of EE2.

PIP: Researchers with the pharmaceutical manufacturer Schering AG in Berlin, Germany, conducted a double-blind clinical trial in 54 healthy, postmenopausal women to compare the pharmokinetic properties of two new estrogens (ZK 136295 and ZK 115194) with those of ethinyl estradiol (EE2). Specifically, they examined whether one or both of the new estrogens improved bioavailability with less inter-subject variability than EE2. The dosage included single intravenous (60 mcg) and oral (120 and 240 mcg) administration. ZK 115195 differs from natural estradiol by 14alpha, 17alpha-bridging, which should prevent early metabolic degradation during absorption and passage through the liver. ZK 136295 is the corresponding derivative of endogenous estriol. All three compounds were rapidly distributed throughout the body. ZK 136295 had the shortest mean terminal half-life; ZK 115194 had the longest (12.3 vs. 28.7 hours); and EE2 had a mean terminal half-life of 26.1 hours. Oral administration of 120 mcg effected an absolute bioavailability of about 40% for ZK 136295 and EE2. The inter-individual variation was high (variation coefficient = 44% and 67%) for both compounds. When the oral dose was 240 mcg, systemic availability increased dose-dependently for ZK 136295 and EE2 to around 70% with the same high inter-individual variation. Oral administration of 240 mcg of ZK 115194 effected an absolute bioavailability of about 33%. These findings show that the 14alpha, 17alpha-bridging of estradiol does not result in a higher bioavailability than that achieved by introduction of a 17alpha-ethinyl group. Yet, increasing the dose of ZK 115194 and of EE2 from 120 to 240 mcg increased their absolute bioavailability two-fold. In conclusion, even though the pharmacokinetic behavior of the two new estrogens differed markedly, the two estrogens exhibited a reduced and highly variable systemic availability similar to that of EE2.

Identification of 3 alpha-hydroxy-cyproterone acetate as a metabolite of cyproterone acetate in the bile of female rats and the potential of this and other already known or putative metabolites to form DNA adducts in vitro.

Cyproterone acetate (CPA) is a synthetic steroid hormone used in the therapy of prostate cancer in men and different forms of acne and hirsutism in women. CPA has been shown by 32P-postlabeling analysis to bind covalently to hepatic DNA of rats in vivo and in vitro. A prerequisite for DNA adduct formation of CPA is metabolic activation of the drug to a reactive intermediate. In the present study bile was collected from [3H]CPA-treated female rats and, following chromatographic separation of bile extracts, fractions of the eluate were examined for the presence of reactive metabolites which were able to form adducts with calf thymus DNA in vitro. The formation of adducts was detected by 32P-postlabeling analysis. One major metabolite of CPA present in the bile extracts was isolated and, following a thorough structural elucidation by mass spectrometry and 1H-NMR, this metabolite was identified as 3 alpha-hydroxy-cyproterone acetate (3 alpha-OH-CPA). This metabolite was able to form the same major adduct in vitro which has been observed before in CPA-treated rats in vivo and in rat hepatocytes in vitro. A number of already known or putative metabolites of CPA were available as authentic standards and these were also examined for their propensity to form adducts in vitro. A positive result was obtained for 3-O-acetyl-cyproterone acetate, which formed the same major adduct as 3 alpha-OH-CPA. However, the presence of this putative metabolite in rat bile could not be demonstrated. Besides 3 alpha-OH-CPA, additional reactive metabolites of CPA were present in the bile extracts, however, since these were only minor components, their chemical structures could not be elucidated.

Pharmacokinetics of nocloprost in human volunteers and its relation to dose.

The pharmacokinetics and absolute bioavailability of nocloprost, a synthetic PGE2-analogue with cytoprotective properties, was investigated in human volunteers as a function of the dose. Ten young male volunteers received nocloprost 5 micrograms i.v. and 100, 200 and 400 micrograms p.o. in random order at weekly intervals. Serum nocloprost levels were monitored for up to 12 h after each dose, using a specific, validated assay. After nocloprost 5 micrograms i.v. the highest serum level of 373 pg.ml-1 was found in the first sample 5 min after injection, and the subsequent decline showed one or two phases, with half-lives of 4 and 49 min. The AUC was 89 pg.h.ml-1, the total plasma clearance was 13.2 ml.min-1.kg-1, and the volume of distribution at steady state was 0.16 l.kg-1. After oral administration the maximum serum level and AUC increased in proportion to the dose. tmax showed a wide scatter, with an average value of about 30 min independent of the dose. Although not detectable in every subject, post maximum serum levels declined biphasically, with half-lives of ca 10 and 35-40 min. The absolute bioavailability after oral administration averaged about 2% and was independent of the dose.

[Experimental study using porous, vascularizable polytetrafluoroethylene in preformed free flaps]. / Experimentelle Untersuchung zur Anwendung poröser, vaskularisierbarer Polytetrafluorethylene in präformierten freien Lappen.

Following radical tumor resections or severe trauma, particularly in the head and neck region, cartilage or bone grafts serve as frame work in defect reconstruction. As an alternative, porous plastic material was used for preformed free flaps in an experimental study with 28 New Zealand rabbits. Due to ingrowth of fibrous tissue and capillaries, it was possible to obtain prefabricated flaps consisting of vascularized porous plastic, a thin layer of fatty gliding tissue and full thickness skin graft. The blood supply of all three layers of the transplant was confirmed by microangiography, Tc 99 m labeled red blood cells and histological examination.

[Vascularized porous synthetics as framework for preformed free flaps]. / Vaskularisierte poröse Kunststoffe als Gerüstmaterial für präformierte freie Lappen.

Porous plastic materials are being utilized more and more in plastic and reconstructive surgery. It appears to be possible to use these plastic materials as a frame, thus giving support and shape to free flaps. Compared with autologous materials such as bone and cartilage, porous plastic materials facilitate vascularization and tissue ingrowth and do not lead to the development of a surrounding capsule. In an experimental study involving 54 Wistar rats, three porous plastic materials were compared to silicone rubber. The analyses of material performance, microangiography, histological and histometrical observations are encouraging.