Eight weeks of high-intensity interval training versus stretching do not change the psychoneuroendocrine response to a social stress test in emotionally impulsive humans

PURPOSE

Research supports physical activity as a method to heighten stress resistance and resilience through positive metabolic alterations mostly affecting the neuroendocrine system. High-intensity interval training (HIIT) has been proposed as a highly effective time-saving method to induce those changes. However, existing literature relies heavily on cross-sectional analyses, with few randomised controlled trials highlighting the necessity for more exercise interventions. Thus, this study aims to investigate the effects of HIIT versus an active control group on the stress response to an acute psychosocial stressor in emotionally impulsive humans (suggested as being strong stress responders).

METHODS

The study protocol was registered online (DRKS00016589) before data collection. Sedentary, emotionally impulsive adults (30.69 ± 8.20 y) were recruited for a supervised intervention of 8 weeks and randomly allocated to either a HIIT (n = 25) or a stretching group (n = 19, acting as active controls). Participants were submitted to a test battery, including saliva samples, questionnaires (self-efficacy- and perceived stress-related), visual analogue scales (physical exercise- and stress-related), and resting electroencephalography and electrocardiography assessing their reaction to an acute psychological stressor (Trier Social Stress Test) before and after the exercise intervention.

RESULTS

HIIT increased aerobic fitness in all participants, whereas stretching did not. Participants from the HIIT group reported perceiving exercising more intensively than those from the active control group (ƞp2 = 0.108, p = 0.038). No further group differences were detected. Both interventions largely increased levels of joy post-TSST (ƞp2 = 0.209, p = 0.003) whilst decreasing tension (ƞp2 = 0.262, p < 0.001) and worries (ƞp2 = 0.113, p = 0.037). Finally, both interventions largely increased perceived levels of general self-efficacy (ƞp2 = 0.120, p = 0.029).

CONCLUSION

This study suggests that 8 weeks of HIIT does not change the psychoneuroendocrine response to an acute psychological stress test compared to an active control group in emotionally impulsive humans. Further replications of supervised exercise studies highly powered with active and passive controls are warranted.

Lipoprotein (a): Does It Play a Role in Pediatric Ischemic Stroke and Thrombosis?

PURPOSE OF REVIEW

The goal of this paper is to describe the current understanding of lipoprotein (a) (Lp(a)), clinical practice guidelines, and the potential pathophysiological mechanisms that appear to increase the risk of cardiovascular and thromboembolic events, specifically within the pediatric population.

RECENT FINDINGS

The proatherogenic and pro-thrombotic properties of Lp(a) may increase the risk of atherothrombotic disease. In adults, atherosclerotic plaques increase thrombotic risk, but antifibrinolytic and proinflammatory properties appear to have an important role in children. Although it is not well established in neonates, recent studies indicate the risk of incident thrombosis and ischemic stroke are approximately fourfold higher in children with elevated Lp(a) which also increases their risk of recurrent events. Despite this higher risk, Pediatric Lp(a) screening guidelines continue to vary among different medical societies and countries. The inconsistency is likely related to inconclusive evidence outside of observational studies and the lack of specific therapies for children with elevated levels. Additional research is needed to improve understanding of the pro-thrombotic mechanisms of Lp(a), appropriate screening guidelines for Lp(a) in the pediatric population, and to elucidate the short and long term effects of elevated Lp(a) on the risk of pediatric thrombosis and stroke.

Abstract TMP24: Successful Implementation Of A Pediatric Stroke Alert System At A Non-academic Hospital

Introduction: Extensive research exists on the acute treatment of adult strokes, but delayed radiologic diagnosis prevents children from receiving the same interventions. Some academic institutions have implemented pediatric stroke protocols to improve early diagnosis, but without 24/7 in-house pediatric stroke coverage, the protocols are challenging to translate to non-academic hospitals. The goal of this study is to assess the implementation of a pediatric stroke alert protocol at a non-academic institution on time to diagnosis and access to acute treatment.

Methods: This was an observational study. Pre-stroke alert patients admitted Feb. 19, 2014-Feb. 18, 2019 were retrospectively identified by stroke/TIA ICD-10 codes. Post-stroke alert patients were prospectively identified using our hospital notification system beginning Feb. 19, 2019- July 31, 2022 for ED stroke alerts and Feb. 19, 2020-July 31, 2022 for inpatient stroke alerts. Patients transferred with an existing stroke/TIA were excluded from the study. Non-parametric tests were used for statistical analysis.

Results: 19 ED and 25 inpatient pre-stroke alert patients were identified. Post-stroke alert implementation, stroke/TIA was identified in 20/157 ED stroke alerts (12.74%) and 14/33 inpatient stroke alerts (42.42%). No significant difference was seen in time from ED arrival to diagnosis. However, time last seen well to diagnosis of stroke/TIA was significantly decreased for both ED and inpatient alerts (Table 1), resulting in 3 patients receiving intravenous thrombolysis.

Conclusions: Although no significant difference was observed in time from ED arrival to diagnosis, implementation of a pediatric stroke alert protocol helped decrease time last seen well to stroke diagnosis. We speculate that increased awareness of pediatric stroke within the community and among medical staff, together with a defined stroke alert process, helped decrease the time of symptom onset to diagnosis.

The Genetic Landscape of Ischemic Stroke in Children - Current Knowledge and Future Perspectives

Stroke in childhood has multiple etiologies, which are mostly distinct from those in adults. Genetic discoveries over the last decade pointed to monogenic disorders as a rare but significant cause of ischemic stroke in children and young adults, including small vessel and arterial ischemic stroke. These discoveries contributed to the understanding that stroke in children may be a sign of an underlying genetic disease. The identification of these diseases requires a detailed medical and family history collection, a careful clinical evaluation for the detection of systemic symptoms and signs, and neuroimaging assessment. Establishing an accurate etiological diagnosis and understanding the genetic risk factors for stroke are essential steps to decipher the underlying mechanisms, optimize the design of tailored prevention strategies, and facilitate the identification of novel therapeutic targets in some cases. Despite the increasing recognition of monogenic causes of stroke, genetic disorders remain understudied and therefore under-recognized in children with stroke. Increased awareness among healthcare providers is essential to facilitate accurate diagnosis in a timely manner. In this review, we provide a summary of the main single-gene disorders which may present as ischemic stroke in childhood and describe their clinical manifestations. We provide a set of practical suggestions for the diagnostic work up of these uncommon causes of stroke, based upon the stroke subtype and imaging characteristics that may suggest a monogenic diagnosis of ischemic stroke in children. Current hurdles in the genetic analyses of children with ischemic stroke as well as future prospectives are discussed.

[Navigated liver surgery : Current state and importance in the future]

The preoperative computer-assisted resection planning is the basis for every navigation. Thanks to modern algorithms, the prerequisites have been created to carry out a virtual resection planning and a risk analysis. Thus, individual segment resections can be precisely planned in any conceivable combination. The transfer of planning information and resection suggestions to the operating theater is still problematic. The so-called stereotactic liver navigation supports the exact intraoperative implementation of the planned resection strategy and provides the surgeon with real-time three-dimensional information on resection margins and critical structures during the resection. This is made possible by a surgical navigation system that measures the position of surgical instruments and then presents them together with the preoperative surgical planning data. Although surgical navigation systems have been indispensable in neurosurgery and spinal surgery for many years, these procedures have not yet become established as standard in liver surgery. This is mainly due to the technical challenge of navigating a moving organ. As the liver is constantly moving and deforming during surgery due to respiration and surgical manipulation, the surgical navigation system must be able to measure these alterations in order to adapt the preoperative navigation data to the current situation. Despite these advances, further developments are required until navigated liver resection enters clinical routine; however, it is already clear that laparoscopic liver surgery and robotic surgery will benefit most from navigation technology.

Sensorimotor training and whole-body vibration training have the potential to reduce motor and sensory symptoms of chemotherapy-induced peripheral neuropathy-a randomized controlled pilot trial

Chemotherapy-induced peripheral neuropathy (CIPN) is a prevalent and clinically relevant side effect of chemotherapy. The symptoms diminish patients' quality of life and represent a decisive limiting factor for medical therapy. To date, effective treatment options are lacking. Specific exercise interventions have proven promising to target relevant symptoms. We conducted a prospective, four-armed, randomized, controlled trial, to evaluate the effects of sensorimotor training (SMT) and whole-body vibration training (WBV) on patients with CIPN. Participants (N = 40) were randomized to either one of two intervention groups (SMT N = 10 or WBV N = 10) or oncological control group (N = 10) and matched by gender and age with a healthy control (N = 10). The intervention groups exercised twice a week for 6 weeks. Primary endpoint was the reduction of CIPN-related symptoms (improve peripheral deep sensitivity, Achilles tendon reflex (ASR) and patellar tendon reflex (PSR), light-touch perception, sense of position, and lower leg strength). Secondary endpoints were nerve conduction velocity and amplitude, balance control, quality of life, and CIPN-related pain. Patients exercising improved sensory and associated motor symptoms. Significant intergroup differences were found for the tendon reflexes (ASR P = .017 and PSR P = .020), peripheral deep sensitivity (P = .010), and pain (P = .043). Furthermore, tendencies were found regarding the subjective improvement of symptoms (P = .075) and two subscales of the EORTC-QLQ-C30 questionnaire: pain (P = .054) and dyspnea (P = .054). The results for the SMT group were superior regarding the tendon reflexes, and a tendency regarding the subjective report of symptoms, while WBV was superior regarding pain. SMT and WBV behold a large potential to reduce CIPN-related symptoms and can be considered feasible and safe for patients with CIPN (compliance 97.5%, no adverse events).Registration: DRKS00013027.

Manipulating Surface States of III-V Nanowires with Uniaxial Stress

III-V compound semiconductors are indispensable materials for today's high-end electronic and optoelectronic devices and are being explored for next-generation transistor logic and quantum technologies. III-V surfaces and interfaces play the leading role in determining device performance, and therefore, methods to control their electronic properties have been developed. Typically, surface passivation studies demonstrated how to limit the density of surface states. Strain has been widely used to improve the electronic transport properties and optoelectronic properties of III-Vs, but the potential of this technology to modify the surface properties still remains to be explored. Here we show that uniaxial stress induces a shift in the energy of the surface states of III-V nanowires, modifying their electronic properties. We demonstrate this phenomenon by modulating the conductivity of InAs nanowires over 4 orders of magnitude with axial strain ranging between -2.5% in compression and 2.1% in tension. The band bending at the surface of the nanostructure is modified from accumulation to depletion reversibly and reproducibly. We provide evidence of this physical effect using a combination of electrical transport measurement, Raman spectroscopy, band-structure modeling, and technology computer aided design (TCAD) simulations. With this methodology, the deformation potentials for the surface states are quantified. These results reveal that strain technology can be used to shift surface states away from energy ranges in which device performance is negatively affected and represent a novel route to engineer the electronic properties of III-V devices.

Increased water contamination and grow-out Pekin duck mortality when raised with water troughs compared to pin-metered water lines using a United States management system

Controversy has developed as to whether or not pin-metered water lines or water troughs are more appropriate for Pekin ducks. We hypothesized that water troughs would show improved duck body conditions and environmental quality compared to pin-metered water lines. To test this hypothesis, we housed ducks in 2 barns, one with water lines and one with water troughs. Water troughs were constructed to meet RSPCA guidelines for number and density of ducks and with recently described verandas. Ducks were divided into 4 pens per barn (n=1,000 ducks/pen). The study was then repeated (n=8 pens per water source) in a cross-over design so the barns each contained the opposite water source to the first experiment. We scored the ducks' body condition using an established scoring rubric and analyzed using SAS Proc GLM-Mix as binomial data. Ducks housed with water troughs showed higher (thus worse condition; P<0.001) scores for eyes, nostrils, feather quality, feather cleanliness, and foot pads. We also compared water condition, water quality, and duck mortality using a Student t test for both water sources each week. We found that the water troughs showed higher iron (P<0.001), nitrites (P<0.001), pH (P<0.01), and bacterial growth (P<0.001). The bacterial growth was shown to have higher (P<0.001)E. coli, coliforms, and Staphylococcusin the water troughs. Water lines typically showed no bacterial growth in culture-based assays. Ducks housed with water troughs used greater (P=0.001) volumes of water compared to ducks housed with water lines. Ducks with water troughs also showed a greater percent (P=0.008) mortality at all ages compared to ducks with water lines. These data suggest that water troughs may not be beneficial for duck welfare and could adversely impact both environment and duck or human health.

Exercise-induced Natural Killer Cell Activation is Driven by Epigenetic Modifications

Exercise has been proven to reduce the risk and progression of various diseases, such as cancer, diabetes and neurodegenerative disorders. Increasing evidence suggests that exercise affects the cytokine profile and changes distribution and function of tumor-competitive immune cells. Initial studies have shown that different exercise interventions are associated with epigenetic modifications in different tissues and cell types, such as muscle, fat, brain and blood. The present investigation examines the effect of an intense endurance run (half marathon) on global epigenetic modifications in natural killer (NK) cells in 14 cancer patients compared to 14 healthy controls. We were able to show that histone acetylation and NKG2D expression, a functional NK cell marker, were elevated for at least 24 h after the run. Thus, this is the first study to present a potential mechanism of how exercise may impact NK cell activity on the subcellular level. Further studies should focus on epigenetic mechanisms and dose-dependent effects of exercise.

Charge transfer doping of silicon

We demonstrate a novel doping mechanism of silicon, namely n-type transfer doping by adsorbed organic cobaltocene (CoCp2*) molecules. The amount of transferred charge as a function of coverage is monitored by following the ensuing band bending via surface sensitive core-level photoelectron spectroscopy. The concomitant loss of electrons in the CoCp2* adlayer is quantified by the relative intensities of chemically shifted Co2p components in core-level photoelectron spectroscopy which correspond to charged and neutral molecules. Using a previously developed model for transfer doping, the evolution in relative intensities of the two components as a function of coverage has been reproduced successfully. A single, molecule-specific parameter, the negative donor energy of -(0.50±0.15)  eV suffices to describe the self-limiting doping process with a maximum areal density of transferred electrons of 2×1013  cm-2 in agreement with the measured downward band bending. The advantage of this doping mechanism over conventional doping for nanostructures is addressed.

Fast Estimation of the Vascular Cooling in RFA Based on Numerical Simulation

We present a novel technique to predict the outcome of an RF ablation, including the vascular cooling effect. The main idea is to separate the problem into a patient independent part, which has to be performed only once for every applicator model and generator setting, and a patient dependent part, which can be performed very fast. The patient independent part fills a look-up table of the cooling effects of blood vessels, depending on the vessel radius and the distance of the RF applicator from the vessel, using a numerical simulation of the ablation process. The patient dependent part, on the other hand, only consists of a number of table look-up processes. The paper presents this main idea, along with the required steps for its implementation. First results of the computation and the related ex-vivo evaluation are presented and discussed. The paper concludes with future extensions and improvements of the approach.

Fast Estimation of the Vascular Cooling in RFA Based on Numerical Simulation

We present a novel technique to predict the outcome of an RF ablation, including the vascular cooling effect. The main idea is to separate the problem into a patient independent part, which has to be performed only once for every applicator model and generator setting, and a patient dependent part, which can be performed very fast. The patient independent part fills a look-up table of the cooling effects of blood vessels, depending on the vessel radius and the distance of the RF applicator from the vessel, using a numerical simulation of the ablation process. The patient dependent part, on the other hand, only consists of a number of table look-up processes. The paper presents this main idea, along with the required steps for its implementation. First results of the computation and the related ex-vivo evaluation are presented and discussed. The paper concludes with future extensions and improvements of the approach.

Formation of venous collaterals and regeneration in the donor remnant liver: volumetric analysis and three-dimensional visualization

PURPOSE

We sought was to quantify and visualize the regeneration of the remnant liver after living donor liver transplantation using computed tomographic (CT) data.

METHODS

For the evaluation of preoperative and follow-up data, we developed a software assistant that was able to compute the volume growth of the remnant liver and liver territories as well as visualize the individual growth of hepatic vessels over time. The software was applied to CT data of 20 donors who underwent right hepatectomy including the middle hepatic vein with at least 3 follow-up examinations in the first year after transplantation.

RESULTS

After donation of a right lobe graft, the remnant liver regenerated by an average 77% of the original volume within the first 3 postoperative months and to 86% within the first year. The growth of the left lateral segments was increased compared with that of segment IV in all cases. The visualization showed the growth of the portal vein and the hepatic veins. With the simultaneous display of pre- and postoperative results, it was possible to detect the formation of collaterals between truncated segment IVb veins and the veins of segment IVa or of the left lateral lobe.

CONCLUSION

The software-assisted analysis of follow-up data yielded additional insight into territorial liver regeneration after living donor liver transplantation and allowed for reliable detection of relevant hepatic vein collaterals using CT data.

Hepatic hilar and sectorial vascular and biliary anatomy in right graft adult live liver donor transplantation

INTRODUCTION

The aim of this study was to analyze vascular and biliary variants at the hilar and sectorial level in right graft adult living donor liver transplantation.

METHODS

From January 2003 to June 2007, 139 consecutive live liver donors underwent three-dimensional computed tomography (3-D CT) reconstructions and virtual 3-D liver partitioning. We evaluated the portal (PV), arterial (HA), and biliary (BD) anatomy.

RESULTS

The hilar and sectorial biliary/vascular anatomy was predominantly normal (70%-85% and 67%-78%, respectively). BD and HA showed an equal incidence (30%) of hilar anomalies. BD and PV had a nearly identical incidence of sectorial abnormalities (64.7% and 66.2%, respectively). The most frequent "single" anomaly was seen centrally in HA (21%) and distally in BD (18%). A "double" anomaly involved BD/HA (7.2%) in the hilum, and HA/PV and BD/PV (6.5% each) sectorially. A "triple" anomaly involving all systems was found at the hilum in 1.4% of cases, and at the sectorial level in 9.4% of instances. Simultanous central and distal abnormalities were rare. In this study, 13.7% of all donor candidates showed normal hilar and sectorial anatomy involving all 3 systems. A simultaneous central and distal "triple" abnormality was not encountered. A combination of "triple" hilar anomaly with "triple" sectorial normality was observed in 2 cases (1.4%). A central "triple" normality associated with a distal "triple" abnormality occurred in 7 livers (5%).

CONCLUSIONS

Our data showed a variety of "horizontal" (hilar or sectorial) and "vertical" (hilar and sectorial) vascular and biliary branching patterns, providing comprehensive assistance for surgical decision-making prior to right graft hepatectomy.

Intrahepatic biliary anatomy derived from right graft adult live donor liver transplantation

OBJECTIVE

The successful management of the bile duct in right graft adult live donor liver transplantation requires knowledge of both its central (hilar) and distal (sectorial) anatomy. The purpose of this study was to provide a systematic classification of its branching patterns to enhance clinical decision-making.

PATIENTS AND METHODS

We analyzed three-dimensional computed tomography (3-D CT) imaging reconstructions of 139 potential live liver donors evaluated at our institution between January 2003 and June 2007.

RESULTS

Fifty-four (n = 54 or 38.8%) donor candidates had a normal (classic) hilar and sectorial right bile duct anatomy (type I). Seventy-eight (n = 78 or 56.1%) cases had either hilar or sectorial branching abnormalities (types II or III). Seven (n = 7 or 5.1%) livers had a mixed type (IV) of a rare and complex central and distal anatomy.

CONCLUSIONS

We believe that the classification proposed herein can aid in the better organization and categorization of the variants encountered within the right-sided intrahepatic biliary system.

Median liver lobe of woodchuck as a model to study hepatic outflow obstruction: a pilot study

BACKGROUND

Hepatic vein outflow obstruction represents an important clinical problem in living-liver transplantation. An animal model is required to study the influence of outflow obstruction on the intrahepatic regulation of liver perfusion and the subsequent effects on liver injury and recovery during liver regeneration. The size of woodchucks enables the use of standard clinical imaging procedures.

AIM

This study aims at describing hepatic vascular and territorial anatomy of the woodchuck liver based on a virtual three-dimensional (3D) visualization of the hepatic vascular tree.

METHODS

Woodchucks (n=6) were subjected to an all-in-one computed tomography (CT) after contrasting the vascular and the biliary tree. CT-images were used for 3D-reconstruction of hepatic and portal veins and calculation of the corresponding portal and hepatic vein territories and their respective volume using hepavision (MeVisLab). A virtual resection was performed following the Cantlie-line and territories at risk were calculated.

RESULTS

The median lobe of the woodchuck liver has a similar vascular supply and drainage as the human liver with two portal (right and left median portal vein) and three hepatic veins (left, middle and right median hepatic vein). The corresponding portal and hepatic vein subterritories are of a similar relative size compared with the human liver. Virtual splitting of the median lobe of the woodchuck liver revealed areas at risk of focal outflow obstruction, as observed clinically.

CONCLUSION

The median liver lobe of the woodchuck represents, to a small extent, the hepatic vascular anatomy of the human liver and is therefore a suitable potential model to correlate repeated imaging of impaired liver perfusion with histomorphological findings of liver damage and regeneration.

ICOS-Dependent and -independent functions of memory CD4 T cells in allograft rejection

Donor-reactive memory T cells undermine the survival of transplanted organs through multiple pathways. We have previously reported that memory CD4 T cells resist treatment with anti-CD154 antibody and donor-specific transfusion (DST/MR1) and promote cardiac allograft rejection via generation of effector CD4 T cells and alloantibody. We hypothesized that the helper functions of memory CD4 T cells are independent of T-cell costimulation through CD154 but instead are regulated by alternative costimulatory pathways. This study investigated how blocking ICOS/B7RP-1 interactions affects functions of donor-reactive memory CD4 T cells. Treatment with blocking anti-ICOS mAb synergized with DST/MR1 and prolonged mouse cardiac allograft survival despite the presence of donor-reactive memory CD4 T cells. While blocking ICOS did not diminish the expansion of preexisting memory CD4 T cells or the induction of allospecific effector T cells, it did inhibit recruitment of the activated memory and effector T cells into the graft. In addition, anti-ICOS mAb treatment in combination with DST/MR1 prevented help provided by memory CD4 T cells for production of donor-specific IgG antibody. These results demonstrate the potential efficacy of ICOS blockade in sensitized transplant patients and provide the foundation for rational use of ICOS blockade in combination with other graft-prolonging strategies.

Virtuelle hepatobiliäre Chirurgie - computerunterstützte Resektionsplanung an der dreidimensional rekonstruierten Leber

Recent developments in image-based computer assistance provide an improved visualisation of the intrahepatic vascular branching system in a virtual three-dimensional model of the liver, allowing a quantitative assessment of any vascular territory. The advantages of computer-assisted resection planning refer to a better preoperative assessment of functional resectability in areas at risk for either devascularisation or impaired drainage. In selected cases, this information may have a considerable influence on operative planning, especially with regard to the extent of resection or the need for vascular reconstruction. Due to the great anatomical variability of the intrahepatic branching patterns of the right liver lobe, this seems to be particularly important in extended left hepatectomies or in repeat hepatectomy when intrahepatic vascular anatomy may be altered. The development of navigation techniques to ensure the accurate application of the preoperative planned resection line is under investigation but not available yet.

Preoperative volume prediction in adult living donor liver transplantation: how much can we rely on it?

Accurate preoperative prediction of functional donor and remnant hemiliver volumes in live donor liver transplantation is essential in preventing postoperative liver failure and optimizing safety. Our aim was (1) to evaluate volume variability associated with multiphasic CT imaging and (2) to determine over- or under-estimations of 3-D CT graft-volume assessments based on 'largest' versus 'smallest' CT phases with respect to intraoperative findings. Native, arterial and venous phase CT images from 83 potential live liver donors were subject to 3-D CT liver volume calculations and virtual 3-D liver partitioning. Estimates were compared to intraoperative volumes obtained in 43 cases. Calculated (preoperative) graft-volume-body-weight-ratios (GVBWR) versus measured (intraoperative) graft-weight-body-weight-ratios (GWBWR) were analyzed. Significant differences in total liver volume- and in graft-liver volume calculations were found among the largest (venous) and smallest (native) CT phases. High significant overestimations were observed in graft-volume determinations and in GVBWR-calculations based on the 'largest' CT phase when compared to intraoperatively obtained graft-weight and -GWBWR values. In contrast, differences among intraoperative measurements and preoperative calculations based on the 'smallest' CT phase yielded less significant overestimations. While 3-D CT volumetry based on the 'largest' (venous) CT phase is associated with considerable overestimation, 3-D volumetry based on the 'smallest' (native) CT phase accurately matches the intraoperative findings.

Preoperative volume prediction in adult living donor liver transplantation: how much can we rely on it?

Accurate preoperative prediction of functional donor and remnant hemiliver volumes in live donor liver transplantation is essential in preventing postoperative liver failure and optimizing safety. Our aim was (1) to evaluate volume variability associated with multiphasic CT imaging and (2) to determine over- or under-estimations of 3-D CT graft-volume assessments based on 'largest' versus 'smallest' CT phases with respect to intraoperative findings. Native, arterial and venous phase CT images from 83 potential live liver donors were subject to 3-D CT liver volume calculations and virtual 3-D liver partitioning. Estimates were compared to intraoperative volumes obtained in 43 cases. Calculated (preoperative) graft-volume-body-weight-ratios (GVBWR) versus measured (intraoperative) graft-weight-body-weight-ratios (GWBWR) were analyzed. Significant differences in total liver volume- and in graft-liver volume calculations were found among the largest (venous) and smallest (native) CT phases. High significant overestimations were observed in graft-volume determinations and in GVBWR-calculations based on the 'largest' CT phase when compared to intraoperatively obtained graft-weight and -GWBWR values. In contrast, differences among intraoperative measurements and preoperative calculations based on the 'smallest' CT phase yielded less significant overestimations. While 3-D CT volumetry based on the 'largest' (venous) CT phase is associated with considerable overestimation, 3-D volumetry based on the 'smallest' (native) CT phase accurately matches the intraoperative findings.

The "territorial belonging" of the middle hepatic vein: a troublesome dilemma in adult live donor liver transplantation--anatomical evidence based on virtual 3-dimensional-computed tomography-imaging reconstructions

BACKGROUND

The venous drainage of the liver plays an essential role in securing viability of both graft and remnant in live donor liver transplantation (LDLT). There is still controversy on whether the middle hepatic vein (MHV) should be routinely included as part of the graft or retained with the remnant liver. The purpose of this study was to analyze hepatic venous drainage patterns based on information obtained by 3-dimensional CT-imaging reconstructions.

METHODOLOGY

Fifty five potential live liver donors were evaluated between January 2003 and May 2004 at our Institution. We analyzed two anatomical definitions of liver dominance: total liver dominance (TLD) and hemiliver dominance (HLD). The following concepts were addressed: 1) Hepatic vein territories, 2) Hepatic vein dominance relationship, 3) Territorial belonging- patterns of the MHV to the right and left hemilivers, additionally an analysis of venous outflow in the central liver sectors was performed.

RESULTS

Our results showed that: 1) The definitions of dominance: TLD vs. HLD overlap, displaying the MHV belonging, by taking into account the individual right hepatic vein (RHV) variability; 2) A dominant RHV for the whole liver indicates that the RHV is also dominant in the right hemiliver; 3) The MHV belongs predominantly to the left hemiliver (LHL); 4) The left hepatic vein (LHV) is dominant in the LHL.

CONCLUSION

Both dominance definitions provide independent mappings of the liver and offer helpful insight into venous dominance relationship.

Computer-gestützte Operationsplanung bei Leberlebendspenden

INTRODUCTION

The appropriate recipient/donor match is a prerequisite for successful living donor liver transplantation (LDLT). A precise knowledge of the liver anatomy and the functional liver volume plays a key role in allocating live liver donor candidates. With the new software HepaVision, we obtained information on liver mapping by means of virtual 3-dimensional non-invasive imaging reconstructions and were able to perform a virtual simulation of the liver transsection. Aim of our study was to investigate, whether this new computer technology is advantageous in surgery planning for LDLT.

METHODS

From January 2002 until December 2004 355 liver transplantations were performed in our department, of which 36 were LDLT. According to our evaluation protocol 135 potential donors (63 male, 72 female) between 18 to 59 years received preoperatively an all-in-one CT. The acquired data sets were further analysed with the software HepaVision (MeVis, Germany).

RESULTS

Of the 135 evaluated donors, we excluded 99 (73 %) from donation based on the HepaVision-data. Reason for exclusion was an inadequate liver volume (70.8 %) or a risk related anatomical anomaly (2.2 %). In the remaining 36 cases a successful graft donation was possible. There were no postoperative complications in the donors and recipients, directly related to a misjudgment of the anatomy or miscalculation of the liver volume.

CONCLUSION

The systematic use of HepaVision for surgery planning proved to be indispensable for proper donor selection. A virtual simulation of the liver transsection on 3D-model additionally increased the safety of the operation, consequently decreasing the risk for the donor.

Anatomical and physiological classification of hepatic vein dominance applied to liver transplantation

BACKGROUND

Proper outflow reconstruction is essential in LDLT. Preoperative planning requires meticulous attention to hepatic vein dominance patterns. The purpose of our study was to provide a combined anatomical-physiological classification of hepatic vein dominance useful for surgical decision-making in both donors and recipients.

METHODOLOGY

We analyzed 3-dimensional CT-imaging reconstructions of 55 potential live liver donors evaluated at our Institution between January 2003 and May 2004.

RESULTS

Our data revealed that: 1) The middle hepatic vein (MHV) and left hepatic vein (LHV) show a relative lack of anatomical diversity, whereas the right hepatic vein (RHV) exhibits multiple variants, 2) 45% donors had inferior hepatic veins (IHV) with anatomically and physiologically relevant venous drainage territories, 3) The RHV is usually dominant when present as a single vein without anatomical IHV (type 1A), or when considered as a complex with IHV (type 1Bx) (80% vs. 88%), 4) Only 55% of dominant type 1Bx RHV/IHV-complex automatically included a dominant type 1By RHV by itself, 5) A single RHV out of anatomical complex with IHV (type 1By) was dominant in only 48% of our donor candidates, 6) The MHV types 2A and 2By are strongly dominant accounting for up to 57% of total liver volume (TLV).

CONCLUSIONS

We propose a new classification based on both anatomical and physiological hepatic venous configurations. Our model also provides a new nomenclature that can be universally applied to preoperative planning in LDLT.

Electrochemical characterisation of dental alloys: its possibilities and limitations

Dental alloys are metallic biomaterials which have a broad variation of composition compared to technical alloys. It is therefore in the interest of patients and technicians to conduct a good assessment of the electrochemical behaviour of dental alloys in order to collect information about their corrosion resistance. The purpose of this work was to demonstrate possibilities and limitations of two electrochemical techniques: the voltammetry of immobilised microparticles (ViMP) onto lead, and cyclic voltammetry measurements with the help of the mini-cell system (MCS). Based on fingerprints obtained from ViMP it was possible to analyse and differentiate the dental alloys. The results obtained by MCS were comparable with ViMP, but give a better understanding of the corrosion behaviour of the materials.