Comparison between autologous bone grafts and acrylic (PMMA) implants - A retrospective analysis of 286 cranioplasty procedures.

Decompressive craniectomy (DC) is an accepted surgical technique for reducing life-threatening levels of intracranial pressure. Remodelling the cranial vault following DC can constitute a reconstructive challenge and is known to carry significant morbidity. The aim of our study was to evaluate acrylic versus autologous cranioplasty with regard to specific complication rates. A retrospective analysis was conducted of 286 consecutive adult patients who underwent cranioplasty following supratentorial decompressive craniectomy at our institution between January 2003 and June 2013. The patients were followed based on medical records, operative reports, imaging and outpatient contacts in the postoperative course. A total of 221/286 patients in our series received an autologous bone flap. 65/286 cranioplasty procedures were carried out using acrylic (PMMA) implants to cover uni- or bilateral defects. Within the follow-up period a total of 100 operative revisions were performed. 33.3% patients in the autologous bone group and 40.6% of patients in the acrylic group developed complications requiring surgical attention. The main reason for revision was infection with a total of 37 revisions necessary to treat disturbed wound healing. Postoperative sub- and epidural hematomas requiring revision were more frequent in the acrylic group. Resorption of the autologous bone flap requiring operative revision was seen in 8/222 (3.6%) cases. Other complications included loosening of the implant or dislocation. From our data it can be concluded that cranioplasty procedures using autologous bone-flaps and acrylic implants carry signifikant morbidity, but that both are justifiable techniques for cranioplasty in adult patients.

Resonant nano-cluster devices.

The resonance-enhanced absorption (REA) by metal clusters on a surface is an effective technique on which to base bio-optical devices. A four-layer device consisting of a metal mirror, a polymer or glass-type distance layer, a biomolecule interaction layer and a sub-monolayer of biorecognitively bound metal nano-clusters is reported. Experiments indicate a strong influence of the resonator homogeneity on the absorption maximum. Layer stability plays an important role in the overall performance of the device. Techniques and optimised lab protocols to set up biochips that use the REA process in the detection are presented. The sensors show one to three narrow reflection minima in the visible and or infra-red (IR) part of the spectrum and therefore they do not suffer from the spectral limitations associated with spherical gold colloids. Metal clusters (synthesised by thermal step reduction) as well as metal- dielectric shell clusters (synthesised by various shell deposition processes) are used to precisely shift the readout of the device to any frequency in the visible and near IR range. Disposable single-step protein chips, DNA assays as well as complex biochip arrays are established that use various DNARNA, antigen-antibody and protein-protein interaction systems.

Synthesis, characterization, and cytotoxicity of trifunctional dinuclear platinum complexes: comparison of effects of geometry and polyfunctionality on biological activity.

The synthesis of two new isomeric trifunctional dinuclear platinum complexes of formula [¿PtCl(NH(3))(2)¿micro-NH(2)(CH(2))(6)NH(2)-¿PtCl(2)(N H(3))¿](+) (1, 2/c,c and 1,2/t,c) is reported. Their biological activity in selected human tumor cell lines sensitive and resistant to CDDP (cisplatin, cis-[Pt(NH(3))(2)Cl(2)]) is described and compared with the profile for their bifunctional analogues, [¿cis/trans-PtCl(NH(3))(2)¿(2)micro-NH(2)(CH(2))(6)NH(2)](2+ ). The trifunctional dinuclear platinum complexes showed a unique profile of cytotoxicity against human cancer cell lines, with low resistance factors in A2780, CH1, and 41M cell lines. The resistance factor is dependent on the geometry of the Pt coordination spheres - suggesting that these may be associated with DNA-binding modes. Retention of activity against CDDP-resistant cell lines and a different spectrum of activity compared to CDDP and also within different classes of polynuclear platinum complexes suggest that not only are they mechanistically different from mononuclear platinum complexes but also each individual class of polynuclear platinum structure may have its own unique character.

Multinuclear metal nucleobase complexes.

Of all properties of metal nucleobase complexes, formation of multinuclear species appears to be an outstanding feature. After a brief introduction into well known polymeric metal nucleobase complexes, three aspects recently Studied in our laboratory will be dealt with in more detail: (i) Heteronuclear complexes derived from trans-[(amine)(2)Pt(1-MeC)(2)](2+) (1-MeC=1-methylcytosine). They form, e. g. with Pd(II) or Hg(II), upon single deprotonation of the exocyclic amino group of each 1-MeC ligand, compounds of type trans-[(amine)(2)Pt(1-MeC-)(2)MY](n+), displaying Pt-M bond formation. (ii) Cyclic nucleobase complexes derived from cis-a(2)Pt(II). A cyclic compound of composition {[(en)Pt(UH-N(1),N(3))](4)}(4+) (UH=monoanion of unsubstituted uracil) is presented and the analogy with organic calix-[4]-arenes is pointed out. (iii) Cyclic nucleobase complexes from trans-a(2)Pt(II). Possible ways for the preparation of macrocyclic nucleobase complexes containing trans-a(2)Pt(II) linkages are outlined and precursors and intermediates are presented.