[Organ injuries due to thoracic trauma : Diagnostics, clinical importance and treatment principles]. / Organverletzungen im Rahmen des Thoraxtraumas : Diagnostik, klinischer Stellenwert und therapeutische Prinzipien.

Thoracic trauma can be a life-threatening condition due to the involvement of vital organs, such as the heart, lungs, tracheobronchial tree and the great vessels. A coordinated interdisciplinary management is vital for the survival of the injured person. Modern diagnostic procedures provide an essential basis for the surgical treatment of patients. Surgical treatment principles include insertion of chest drainage, emergency thoracotomy, complex bronchoplastic and vascular reconstructive techniques and cardiac surgical maneuvers. For this reason highly complex surgical procedures are available, which can be effectively and specifically integrated into an interdisciplinary concept. In this review, the most frequent and prognostically relevant conditions, the indicated diagnostics and their significance as well as the surgical treatment principles, are comprehensively presented under consideration of the clinical situation.

[Surgery of colorectal lung metastases : Results of a survey in Germany]. / Chirurgie pulmonaler Metastasen des kolorektalen Karzinoms : Ergebnisse einer Umfrage in Deutschland.

BACKGROUND: There is no evidence from randomized trials on the prognostic significance of pulmonary metastasectomy of colorectal cancer. The objective of this study was to assess the current criteria for indications, preoperative diagnostics and preferred operative techniques of pulmonary metastasectomy in Germany. METHODS: An anonymous survey was carried out in 239 German centers performing thoracic surgery in October 2015. RESULTS: Chest computed tomography (CT, 98%), liver CT (62%), pelvis CT (39%) and fluorodeoxyglucose positron emission tomography (FDG-PET, 37%) were used by the respondents (65% of participants) for preoperative staging. Pulmonary metastasectomy was most commonly performed for solitary lung metastasis without extrathoracic disease (96%), >1 ipsilateral lung metastases without extrathoracic disease (94.8%), solitary lung metastasis with resectable hepatic metastases (92%) and resectable bilateral lung metastases without extrathoracic disease (91%). Of the respondents 95% performed open lung metastasectomy, 82% video-assisted thoracic surgery, 18% radiofrequency ablation, 53% used laser-assisted open resection and 46% indicated that there was no scientific consensus on pulmonary metastasectomy. CONCLUSION: The majority of respondents performed pulmonary metastasectomy for solitary and multiple, unilateral and bilateral lung metastases without extrathoracic disease and/or local recurrence of primary tumors. The coexistence of resectable liver metastases was not an absolute contraindication for surgery. Of the respondents 46% expressed the need for prospective randomized studies to improve the evidence on pulmonary metastasectomy for colorectal cancer.

[Neoadjuvant Radiochemotherapy Followed by Curative Resection in Patients with Advanced Non-Small Cell Lung Cancer in Stage IIIA/IIIB: Prognostic Factors and Results]. / Neoadjuvante Radiochemotherapie gefolgt von kurativer Resektion im fortgeschrittenen Stadium IIIA/IIIB eines nicht kleinzelligen Lungenkarzinoms: prognostische Faktoren und Ergebnisse.

The role of surgical lung resection following neo-adjuvant radio-chemotherapy (RCT) in patients with locally advanced non-small cell lung cancer (NSCLC) is yet not clearly defined. The aim of our study was to analyze the postoperative survival and to identify relevant prognostic factors. 46 patients underwent curative resections after neo-adjuvant RCT for locally advanced NSCLC (IIIA/IIIB) between February 2008 and February 2015. A retrospective data analysis regarding preoperative regression status, perioperative mortality, postoperative survival, patho-histological remission, relapse pattern and other prognostic factors was performed. A neo-adjuvant RCT with a median radiation dose of 50.4 [range, 45-60] Gy was performed in 44 (96 %) patients. Partial and/or complete regression was observed in 32 (70 %) patients. R0-resection was achieved in 44 (96 %) patients. The 30-day mortality was 4 % and the perioperative morbidity was 37 %. The overall and progression free 5-year survival rate was 47 % and respectively 45 % [in median 58 months]. The 5-year survival rate of 64 % in the "responder"-group was significantly better when compared with 24 % in the "non-responder"-group (p = 0.038). The tri-modality therapy improved the prognosis in patients with locally advanced NSCLC (stage IIIA/IIIB). The complete patho-histological remission is an important prognostic factor for better long term survival. Dividing the patients in "responder" and "non-responder" after neo-adjuvant RCT may have large therapeutically consequences in the future.

[Oligometastatic non-small cell lung cancer--surgical options and therapy strategies]. / Oligometastasiertes nicht kleinzelliges Lungenkarzinom--chirurgische Optionen und Behandlungsstrategien.

OBJECTIVE: The therapeutic strategies for oligometastatic non-small cell lung cancer have changed over the last decade from palliative to curative intent. The role of surgery in this multimodal treatment in selected patients remains a subject for open discussion. METHODS: Data of 34 patients with one or two metastases treated from January 1998 to January 2013 were retrospectively analysed. RESULTS: The mean age was 59.7 (± 10.1) years. The male vs. female ratio was 20 vs. 14. Adenocarcinoma was the most common histological type (58.8 %). The synchronous metastases were present in 15 patients, the metachronous in 19 patients. Single metastases were present in 27 patients, two metastases in 7 patients. The most frequently involved organs were brain (58.8 %) and the lungs (23.6 %). The primary tumour resection was achievable in 20 patients as R0 and in 2 patients as R1. The median overall survival, the local and the systemic disease-free survivals in the entire group were 40, 38 and 25 months, respectively. The 5 year overall survival, the 5 year local and systemic disease-free survivals were 29.2, 26.9 and 16.5 %, respectively. The treatment strategies including surgery for primary tumour as well as for pulmonary metastases site, combined with the lymph node dissection and the resection of the extracerebral and cerebral metastases, were identified as independent prognostic factors for long-term survival. CONCLUSION: Surgery in oligometastatic non-small cell lung carcinoma is feasible for primary tumour and for metastases. It is an effective option in the multimodal treatment in highly selected patients. The lymph node dissection should remain an important integral part of the surgical treatment.

[V. A. C. INSTILL® therapy - new option in septic thoracic surgery]. / V. A. C.-INSTILL®-Therapie - neue Wege in der septischen Thoraxchirurgie.

BACKGROUND: The V. A. C. INSTILL® therapy is an innovative process for treating chronic wounds that are not optimally accessible to a systemic antibiotic therapy or infected with multi-resistant pathogens. We report on our first experience and applications of V. A. C. INSTILL® therapy in the field of septic thoracic surgery. MATERIALS AND METHODS: V. A. C. INSTILL therapy was used in 11 cases between 11/2009 and 01/2012. Three patients had sternum osteomyelitis (2 MRSA, 1 Finegoldia magna). In 3 patients chronic pleural empyema after lobectomy (1 Streptococcus viridans, 1 mixed infection with MRSA among others) and after pneumectomy (1 MRSA) were detected. In 2 cases there was an acute pleural empyema with extensive phlegmona in the region of the thoracic soft tissues (2 streptococci). In 1 patient a chronic pleural empyema with MRSA infection was treated. Septic arthritis of the sternoclavicular joint with joint destruction and extensive phlegmona in the region of the cervical soft tissues (1 Streptococcus pneumoniae, 1 Staphylococcus aureus) was treated in 2 patients. In all cases instillation of the wound was performed with Lavasept 0.2 %. Swabs of the wound were taken before starting and after ending V. A. C. INSTILL® therapy as well as before wound closure. RESULTS: Mean patient age was 48.8 ± 18.9 years. V. A. C. INSTILL® therapy was performed for 6.5 ± 1.7 days. Instillation time amounted to 21.7 ± 5.7 s. The duration of action was standardised at 18 min in all cases. In 2 cases (1 MESA, 1 finegoldia) the V. A. C. INSTILL® therapy was repeated. In 10 patients a sterile wound status was achieved before secondary wound closure. All wounds underwent secondary closure without recurrence. CONCLUSIONS: Chronic osteomyelitis with MRSA infections as well as chronically infected residual cavities after empyema surgery and extensive phlegmona are possible indications for V. A. C. INSTILL® therapy in order to help eradicating the infection as quickly and as completely as possible.

Tuning protein GlnB-Hs surface interaction with silicon: FTIR-ATR, AFM and XPS study.

Herbaspirillum seropedicae GlnB (GlnB-Hs) is a signal transduction protein involved in the control of nitrogen, carbon and energetic metabolism. The adsorption of GlnB-Hs deposited by spin coating on hydrophilic and hydrophobic silicon forms a thin layer that was characterized using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared attenuated total reflectance spectroscopy (FTIR-ATR). AFM allowed the identification of globular, face-up donut like array of protein on hydrophilic silicon substrate, favoring deprotonated residues to contact the silicon oxide surface. Over hydrophobic silicon, GlnB-Hs adopts a side-on conformation forming a filament network, avoiding the contact of protonated residues with silicon surface. XPS allowed us to determine the protonated and non-protonated states of nitrogen 1s (N 1s). The FTIR-ATR measurements provided information about protein secondary structure and its conservation, after surface adsorption.

MH2c: Characterization of major histocompatibility α-helices - an information criterion approach.

Major histocompatibility proteins share a common overall structure or peptide binding groove. Two binding groove domains, on the same chain for major histocompatibility class I or on two different chains for major histocompatibility class II, contribute to that structure that consists of two α-helices ("wall") and a sheet of eight anti-parallel beta strands ("floor"). Apart from the peptide presented in the groove, the major histocompatibility α-helices play a central role for the interaction with the T cell receptor. This study presents a generalized mathematical approach for the characterization of these helices. We employed polynomials of degree 1 to 7 and splines with 1 to 2 nodes based on polynomials of degree 1 to 7 on the α-helices projected on their principal components. We evaluated all models with a corrected Akaike Information Criterion to determine which model represents the α-helices in the best way without overfitting the data. This method is applicable for both the stationary and the dynamic characterization of α-helices. By deriving differential geometric parameters from these models one obtains a reliable method to characterize and compare α-helices for a broad range of applications. PROGRAM SUMMARY: Program title: MH2c (MH helix curves) Catalogue identifier: AELX_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AELX_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 327 565 No. of bytes in distributed program, including test data, etc.: 17 433 656 Distribution format: tar.gz Programming language: Matlab Computer: Personal computer architectures Operating system: Windows, Linux, Mac (all systems on which Matlab can be installed) RAM: Depends on the trajectory size, min. 1 GB (Matlab) Classification: 2.1, 4.9, 4.14 External routines: Curve Fitting Toolbox and Statistic Toolbox of Matlab Nature of problem: Major histocompatibility (MH) proteins share a similar overall structure. However, identical MH alleles which present different peptides differ by subtle conformational alterations. One hypothesis is that such conformational differences could be another level of T cell regulation. By this software package we present a reliable and systematic way to compare different MH structures to each other. Solution method: We tested several fitting approaches on all available experimental crystal structures of MH to obtain an overall picture of how to describe MH helices. For this purpose we transformed all complexes into the same space and applied splines and polynomials of several degrees to them. To draw a general conclusion which method fits them best we employed the "corrected Akaike Information Criterion". The software is applicable for all kinds of helices of biomolecules. Running time: Depends on the data, for a single stationary structure the runtime should not exceed a few seconds.

Vanadium oxide nanoparticles as optical sensors of cysteine.

We report on the synthesis of vanadium oxide nanoparticles using the laser ablation in solution technique. The particles were characterized by dynamic light scattering-DLS, transmission electron microscopy-TEM, X-ray diffraction-XRD, X-ray photoelectron spectroscopy-XPS and UV-Vis optical spectroscopy. The oxide nanoparticles are mainly composed of tetragonal V2O5, a semiconductor with a 2.2 eV band gap. The interaction of the nanoparticles with cysteine, a very important aminoacid present in proteins, was studied. Upon reaction with cysteine, the bandgap of the nanoparticles shifts to the ultraviolet region at 2.87 eV. This color change from yellow to transparent can be used for selective cysteine sensing. Additionally, the intervalence band of the optical absorption spectra shows capability for cysteine sensing in the microM range.

Is an intuitive convergence definition of molecular dynamics simulations solely based on the root mean square deviation possible?

Molecular dynamics is a commonly used technique in computational biology. One key issue of each molecular dynamics simulation is: When does this simulation reach equilibrium state? A widely used way to determine this is the visual and intuitive inspection of root mean square deviation (RMSD) plots of the simulation. Although this technique has been criticized several times, it is still often used. Therefore, we present a study proving that this method is not reliable at all. We conducted a survey with participants from the field in which we illustrated different RMSD plots to scientists in the field of molecular dynamics. These plots were randomized and repeated, using a statistical model and different variants of the plots. We show that there is no mutual consent about the point of equilibrium. The decisions are severely biased by different parameters. Therefore, we conclude that scientists should not discuss the equilibration of a molecular dynamics simulation on the basis of a RMSD plot.

A four-muscle-flap for thoracomyoplasty in patients with sacrificed thoracodorsal vessels.

UNLABELLED: Defects after prior posterolateral thoracotomy and with concomitant bronchiopleural fistula remain a challenge for the plastic surgeon. In most of the cases, the thoracodorsal artery division after posterolateral thoracotomy impairs the vascularisation supply of the latissimus dorsi, resulting in the loss of this option for closure of the pleural cavity. Therefore, the adequate filling of residual empyema space and/or surgical closure of the bronchial stump insufficiency needs additional tissue to overcome this situation. We present an alternative approach using a four-muscle-flap technique including the infraspinatus, the subscapularis and the teres major and minor muscle group, all pedicled from the subscapular artery as a part of a modified thoracomyoplasty technique for closing the residual empyema space and bronchial stump insufficiency. METHODS: Between 2002 and 2008, we performed the four-muscle-flap on seven patients (mean age 68±7.9 years) with residual empyema space. Three cases were combined with a bronchopleural fistula. All patients received a two-stage procedure. First, the thoracic surgeons performed an open-window thoracostomy. This procedure was followed by the definitive surgical treatment after 3-6 months. In cases with an additional bronchial insufficiency, the stump was covered in with a subscapularis muscle. The infraspinatus and the teres muscle group were used to fill the pleural cavity, in combination with the thoracoplasty. RESULTS: In this series, no mortality connected to the procedure was noted. The mean postoperative stay in the intensive care unit (ICU) was 3±2.9 days and the patients were discharged from the hospital after 15±7.6 days. Minor postoperative complications occurred in two cases. Shoulder abduction in all patients was possible up to 90° and has decreased around 15±10° postoperatively. CONCLUSIONS: The division of the thoracodorsal pedicle and the consecutive loss of the latissimus as a reconstructive option remain challenging. The lower shoulder girdle muscles (infraspinatus, subscapularis, teres minor and major) are an adequate alternative for filling residual empyema spaces. The constraint in shoulder movement is minor and acceptable in such situations.

Modified technique for thoracomyoplasty after posterolateral thoracotomy.

OBJECTIVE: Thoracomyoplasty after prior posterolateral thoracotomy (PLT) remains a challenge for the thoracic surgeon. Thoracodorsal artery division after PLT impairs the vascularization supply of the latissimus dorsi muscle (LDM) resulting in muscle mass reduction due to distal atrophy. This makes adequate filling of residual empyema space and/or surgical closure of bronchial stump insufficiency more difficult, and they require alternative surgical procedures. We present an alternative approach using a four-muscle flap technique to include the infraspinatus, the subscapularis and the teres major muscle group, all pedicled from the subscapular artery as a part of a modified thoracomyoplasty technique for closing residual empyema space and bronchial stump insufficiency. METHODS: Between 2002 and 2008 we performed the technique in 7 patients with residual empyema space. Three patients had post-tuberculosis syndrome, 2 had postpneumectomy empyema, and 2 had chronic parapneumonic empyema. Three cases were combined with a bronchopleural fistula. All patients underwent a two-stage procedure. First, open window thoracostomy was performed followed by definitive surgical treatment after 3-6 months. In all cases with bronchial insufficiency the stump was covered with a subscapularis muscle flap. The infraspinatus and the teres muscle group were used in combination with a local thoracoplasty. RESULTS: Mean age was 68 +/- 7.9 years. Time from open window thoracostomy to thoracomyoplasty averaged 4 +/- 1.3 months. The number of resected ribs ranged between 4 and 8. Mean postoperative stay in the ICU was 3 +/- 2.9 days. The thoracic drains were removed after 5 +/- 2.3 days. Total hospital stay was 15 +/- 7.6 days. No hospital mortality was noted. Minor postoperative complications occurred in 2 cases. Shoulder function without pain allowed abduction up to 90 degrees. Function was decreased by 16 +/- 9 degrees compared to preoperative evaluation. No severe progressive scoliosis was noted. CONCLUSIONS: Division of the LDM and its vascular supply after posterolateral thoracotomy results in a reduction of muscle mass. The shoulder girdle muscles offer an adequate alternative to fill residual empyema space with acceptable long-term results and restriction in shoulder motion. In all cases with bronchial fistula, bronchial stump closure with a pedicled subscapular muscle was an effective alternative operative technique.

Ferromagnetism induced by oxygen and cerium vacancies above the percolation limit in CeO2.

We studied the structural, chemical and magnetic properties of non-doped ceria (CeO(2)) thin films electrodeposited on silicon substrates. Experimental results confirm that the observed room temperature ferromagnetism is driven by both cerium and oxygen vacancies. We investigated ceria films presenting vacancy concentrations well above the percolation limit. Irradiation experiments with neon ions were employed to generate highly oxygen defective CeO(2-δ) structures. X-ray photoelectron spectroscopy and x-ray absorption near-edge structure spectroscopy were used to estimate the concentration of Ce(3+) sites in the films, which can reach up to 50% of Ce(3+) replacing Ce(4+), compared to a stoichiometric CeO(2) structure. Despite the increment of structural disorder, we observe that the saturation magnetization continuously increases with Ce(3+) concentration. Our experiments demonstrate that the ferromagnetism observed in ceria thin films, highly disordered and oxygen-deficient, preserving the fluorite-type structure only in a nanometer scale, remains intrinsically stable at room temperature.

Graphical user interfaces for molecular dynamics-quo vadis?

In the past years an increasing number of graphical user interfaces for Molecular Dynamics (MD) were presented and concomitantly, more and more Molecular Dynamics studies were published. With the easier application of MD software packages the field runs the risk however, of being pervaded with unreliable results. Therefore, possible benefits and caveats have to be carefully balanced. Here we outline in which respects a broader access of MD via graphical user interfaces may help to increase the usability of Molecular Dynamics simulations while maintaining their quality.

Morphology, structure, and magnetism of FeCo thin films electrodeposited on hydrogen-terminated Si(111) surfaces.

In this work we describe the fabrication of FeCo alloy (less than 10 at% Co) thin films from aqueous ammonium sulfate solutions onto n-type Si(111) substrates using potentiostatic electrodeposition at room temperature. The incorporation of Co into the deposits tends to inhibit Fe silicide formation and to protect deposits against oxidation under air exposure. As the incorporation of Co was progressively increased, the sizes of nuclei consisting of FeCo alloy increased, leading to films with a highly oriented body-centered cubic structure with crystalline texture, where (110) planes remain preferentially oriented parallel to the film surface.

Adsorption of protein GlnB of Herbaspirillum seropedicae on Si(111) investigated by AFM and XPS.

The protein GlnB-Hs (GlnB of Herbaspirillum seropedicae) in diazotroph micro-organisms signalizes levels of nitrogen, carbon, and energy for a series of proteins involved in the regulation of expression and control of the activity of nitrogenase complex that converts atmospheric nitrogen in ammonia, resulting in biological nitrogen fixation. Its structure has already been determined by X-ray diffraction, revealing a trimer of (36 kDa) with lateral cavities having hydrophilic boundaries. The interactions of GlnB-Hs with the well-known Si(111) surface were investigated for different incubation times, protein concentrations in initial solution, deposition conditions, and substrate initial state. The protein solution was deposited on Si(111) and dried under controlled conditions. An atomic force microscope operating in dynamic mode shows images of circular, linear, and more complex donut-shaped protein arrangement, and also filament types of organization, which vary from a few nanometers to micrometers. Apparently, the filament formation was favored because of protein surface polarity when in contact with the silicon surface, following some specific orientation. The spin-coating technique was successfully used to obtain more uniform surface covering.

Synthesis and characterization of disordered layered silica obtained by selective leaching of octahedral sheets from chrysotile and phlogopite structures.

Natural chrysotile fibers and pegmatitic phlogopite were acid-leached under controlled conditions. The resulting products were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, (29)Si nuclear magnetic resonance, transmission electron microscopy, and selected area electron diffraction. The leached products derived of the two clays are similar, consisting of layered hydrated disordered silica with a "distorted" structure resembling the silicate layer existing in the original minerals. A simple model of the "disordered" silica structure is presented.

Application of Ni:SiO2 nanocomposite to control the carbon deposition on the carbon dioxide reforming of methane.

Stable Ni nanoparticles embedded in a mesoporous silica material were used as catalysts for the conversion of methane into synthesis gas. This catalyst has the singular properties of controlling the carbon deposition and deactivation of active sites. A comparative study of our nanocomposites with conventional catalysts showed that impregnation material presented a preferential encapsulation and growth of carbon nanotubes on the metal surface. The impregnated catalyst showed a higher tendency for carbon nanotube and whiskers formation.

Modification of the Interlayer Surface of Layered Copper(II) Hydroxide Acetate with Benzoate Groups: Submicrometer Fiber Generation.

We report on the functionalization of layered copper(II) hydroxide acetate with benzoic acid. The grafting of benzoate groups is characterized by thermogravimetry/differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The submicrometer fiber generation of the grafted material is clearly demonstrated through scanning electron microscopy. Copyright 2001 Academic Press.

Bronchopleural fistula in the surgery of non-small cell lung cancer: incidence, risk factors, and management.

BACKGROUND: The incidence of a bronchopleural fistula (BPF) as a major complication after non-small cell lung carcinoma (NSCLC) surgery has decreased in recent years, due to new surgical refinements and a better understanding of the bronchial healing process. We reviewed our most recent experience with BPFs and tried to determine methods which may effectively reduce its occurrence. METHODS: Data on 490 patients with lung resections for NSCLC over a period from 1990 to 1999 were retrospectively reviewed. Details regarding surgery and the subsequent treatment were carefully reviewed. Particular attention was paid to factors possibly affecting the occurrence of BPFs: the technique of the initial bronchial closure, previous radiation and/or chemotherapy, need for postoperative ventilation and presence of residual carcinomatous tissue at the bronchial suture line. Information about age, sex, clinical diagnosis, associated conditions, TNM stage, period between primary operation and rethoracotomy and postoperative outcome was also recorded. RESULTS: The overall BPF incidence was 4.4% (22/490). There were 21 (95.5%) males and 1 (4.5%) female, mean age was 57.8 years. BPFs occurred after pneumonectomy in 12 (54.6%), after lobectomy in 9 (40.9%) patients and after sleeve resections in 1 (4.5%) patient. Mortality rate was 27.2% (6/22). Right-sided pneumonectomy and postoperative mechanical ventilation were identified as risk factors for BPFs (p<0.05). Initial chest re-exploration was performed in 20 (90.9%) patients. After debridement, the bronchial stump was reclosed by hand suture in 10 (45.4%) patients. All 10 (45.4%) patients with a post-lobectomy- and sleeve resection BPF necessitated completion surgery. The BPF was additionally covered with a vascularized flap in 20 (90.9%) patients. In 2 (9%) patients with small BPFs and poor overall condition the initial treatment was endoscopic. In both the fistula persisted and the stump had to be surgically resutured. CONCLUSIONS: A BPF remains a major complication in the surgery of NSCLC because of its high mortality and morbidity rate. A BPF is more common after right-sided pneumonectomy and is frequently associated with postoperative mechanical ventilation. The management varies according to the initial type of surgery, the size of the BPF, the overall patient condition and that of the remaining lung. Endoscopic treatment is reserved only for small fistulas associated with poor general condition.

Functional characteristics of optimized arterial tree models perfusing volumes of different thickness and shape.

The relationship between the 'shape of an organ' and the 'cost of blood transport' to perfuse its tissue was evaluated on the basis of optimized arterial model trees simulated to perfuse square-based 100-cm(3) volumes of different shape ('flat' versus 'thick' as defined by the ratio of thickness to side-length h/s < or =1). Specifically, the effects of 'shape' on tree structure, blood transport, and on hemodynamic characteristics were investigated. Branching models of arterial trees were generated by constrained constructive optimization (CCO), based on an identical set of model parameters. All model trees were geometrically and topologically optimized for intravascular volume. Tree structures achieved tremendous savings of blood (transport medium) in comparison to a system of separate tubes. Thickening the perfusion volume (increasing h/s) resulted in a significant decrease of mean transport length, deposition time, and intravascular total volume in the tree. 'Thick' perfusion volumes induced CCO trees to branch more symmetrically into a number of equivalent subtrees repetitiously splitting into smaller ones; 'flat' structures were dominated throughout by a few asymmetrically branching major vessels. In summary, we conclude from systematic variation of shape that thicker perfusion volumes (h/s >0.1) facilitate efficient delivery of blood in comparison to large amounts of 'dead volume' to be carried over long distances in very thin pieces of tissue.