More than 30 Years of POSSUM: Are Scoring Systems Still Relevant Today for Colorectal Surgery?

BACKGROUND

The Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) weights the patient's individual health status and the extent of the surgical procedure to estimate the probability of postoperative complications and death of general surgery patients. The variations Portsmouth-POSSUM (P-POSSUM) and colorectal POSSUM (CR-POSSUM) were developed for estimating mortality in patients with low perioperative risk and for patients with colorectal carcinoma, respectively. The aim of the present study was to evaluate the significance of POSSUM, P-POSSUM, and CR-POSSUM in two independent colorectal cancer cohorts undergoing surgery, with an emphasis on laparoscopic procedures.

METHODS

For each patient, an individual physiological score (PS) and operative severity score (OS) was attributed to calculate the predicted morbidity and mortality, respectively. Logistic regression analysis was used to evaluate the possible correlation between the subscores and the probability of postoperative complications and mortality.

RESULTS

The POSSUM equation significantly overpredicted postoperative morbidity, and all three scoring systems considerably overpredicted in-hospital mortality. However, the POSSUM score identified patients at risk of anastomotic leakage, sepsis, and the need for reoperation. Logistic regression analysis demonstrated a strong correlation between the subscores and the probability of postoperative complications and mortality, respectively.

CONCLUSION

Our results suggest that the three scoring systems are too imprecise for the estimation of perioperative complications and mortality of patients undergoing colorectal surgery in the present day. Since the subscores proved valid, a revision of the scoring systems could increase their reliability in the clinical setting.

Quality of Life after Desarda Technique for Inguinal Hernia Repair-A Comparative Retrospective Multicenter Study of 120 Patients

Inguinal hernia repair, according to Desarda, is a pure tissue surgical technique using external oblique fascia to reinforce the posterior wall of the inguinal canal. This has provided an impetus for the rethinking of guideline adherence toward minimally invasive and mesh-based surgery of inguinal hernia. In this study, a retrospective analysis of this technique was conducted in two German hospitals. Between 6/2013 and 12/2020, 120 operations were performed. Analysis included patient characteristics, duration of operation, length of hospital stay, and perioperative complications. Data were used to achieve a matched-pair analysis comparing Desarda to laparoscopic transabdominal preperitoneal (TAPP) hernia repair. Propensity scores were calculated based on five preoperative variables, including sex, age, American Society of Anesthesiology classification, localization, and width of the inguinal hernia in order to achieve comparability. Additionally, we assessed pain level and quality of life (QoL) 12 months postoperatively. The focus of our study was a comparison of QoL to a reference population and TAPP cohort. The study population consisted of 106 male and 14 female patients, and the median age was 37.5 years. The median operation time was 50 min, and the median length of hospital stay was 2 days. At a follow-up of 17 months, the median recurrence rate was 0.8%, and two cases of chronic postoperative pain were recorded. Postoperative QoL does not significantly differ between Desarda and TAPP. In contrast, Desarda patients had a significantly higher QoL compared with the reference population. In summary, Desarda's procedure is a good option as a pure tissue method for inguinal hernia repair.

Acute Mesenteric Ischemia: Preexisting Comorbidity Determines Short-Term Outcome and Quality of Life in Long-Term Survivors

Introduction

Acute mesenteric ischemia (AMI), either arterial or venous, is still a devastating disease with poor prognosis. It is unknown, whether AMI is associated with impaired quality of life (QoL) in long-term survivors.

Material and Methods

This retrospective analysis includes 64 patients with occlusive arterial or venous mesenteric ischemia treated operatively between 2008 and 2016 at the University Medical Center Rostock. Short-term outcome with focus on comorbidities was measured by the Charlson comorbidity index (CCI) an instrument that operationally measures comorbidity based on 17 clinical parameters including age. Operative outcome in view of enterostomy placement and long-term outcome measured as QoL by the EQ-5D in the long-term survivors were evaluated. The EQ-5D is a standardized, self-reported five-dimension QoL questionnaire built to provide a simple and generic measure of health.

Results

Thirty-day mortality was 60.9%, and in-hospital mortality was 70.3% (n = 45). No patient was discharged with a stoma. Patients with a primary anastomosis after the initial operation for AMI had a high leak rate of 27% (4/15 patients) compared to no dehiscence in the group of patients who had secondary anastomosis during second or third laparotomy. The long-term survivors had significantly lower CCI compared to the 45 nonsurvivors (median 4 [3, 4, 5, 6] vs. 6 [4, 5, 6, 7]). All long-term survivors had QoL assessment. QoL score was significantly impaired compared to an age- and sex-matched reference population. This impairment was not due to disease-specific sequelae such as presence of stool deviation or intestinal failure but due to preexisting risk factors as shown by an inverse relation between the CCI and QoL score.

Conclusion

Herein, we show for the first time that long-term QoL in patients with AMI is impaired but this impairment is not due to disease-specific aspects but rather general risk factors underlying the presence of a higher level of comorbidities at the time of AMI.

Supplementing a widely available weight loss program with gamified inhibitory control training: A randomized pilot study

Background

Increasing evidence suggests that targeting self-regulatory processes may improve obesity treatment outcomes. Incorporating gamification principles in inhibitory control training may promote sustained training adherence and resulting benefits. This pilot study evaluated the preliminary efficacy of supplementing an evidence-based weight management program (WW) with sustained gamified inhibitory control training (PolyRules!) on change in Body Mass Index (BMI) among adults with overweight/obesity.

Methods

30 adults with overweight/obesity (M age 49.9 ± 12.4, 86.7% female; 23.3% Hispanic, mean BMI 35.3 ± 6.3) were randomly assigned to receive WW with or without PolyRules! for 12 weeks. The primary outcome was change in BMI from baseline to post-intervention across study arms. Implementation and process indicators were captured to inform larger trials.

Results

Average change in BMI was -0.9 in the WW arm and -1.2 in the WW + PolyRules! arm (Cohen's d = 0.26). In the WW + PolyRules! arm, increased training was associated with greater decreases in BMI (r = -0.506, p = 0.0454). WW + PolyRules! participants completed an average of 60.4% sessions and reported positive experiences. There was no difference in frequency of food (d = -0.02) and weight tracking (d = -0.19) between arms.

Conclusions

Studies in larger samples should evaluate training-related effects on weight. Supplementing WW with gamified inhibitory training appears feasible, with no detrimental effect on engagement.

Assessment of Quality of Life after Endovascular and Open Abdominal Aortic Aneurysm Repair: A Retrospective Single-Center Study

Postoperative quality of life is an important outcome parameter after treatment of abdominal aortic aneurysms. The aim of this retrospective single-center study was to assess and compare the health-related quality of life (HRQoL) of patients after open repair (OR) or endovascular treatment (EVAR), and furthermore to investigate the effect of incisional hernia (IH) formation on HRQoL. Patients who underwent OR or EVAR for treatment of an abdominal aortic aneurysm between 2008 and 2016 at a University Medical Center were included. HRQoL was assessed using the SF-36 questionnaire. The incidence of IH was recorded from patient files and by telephone contact. SF-36 scores of 83 patients (OR: n = 36; EVAR: n = 47) were obtained. The mean follow-up period was 7.1 years. When comparing HRQoL between OR and EVAR, patients in both groups scored higher in one of the eight categories of the SF36 questionnaires. The incidence of IH after OR was 30.6%. In patients with postoperative IH, HRQoL was significantly reduced in the dimensions “physical functioning”, “role physical” and “role emotional” of the SF-36. Based on this data, it can be concluded that neither OR nor EVAR supply a significant advantage regarding HRQoL. In contrast, the occurrence of IH has a relevant impact on the HRQoL of patients after OR.

Use of incisional preventive negative pressure wound therapy in open incisional hernia repair: Who benefits?

Complex surgery of abdominal wall hernia continues to bear the major concern of wound healing disorders. Technical modifications have not been able to sufficiently prevent wound healing impairments or infections, even in clean elective cases, especially when dealing with large-scale hernia defects. Incisional negative pressure wound therapy (iNPWT) in its intentional use as a preventive tool has recently found its way from theoretical and experimental advantages to the clinical routine. Different indications have been defined but evidence is lacking. We performed a retrospective analysis (1/2014-5/2019) of all ventral hernia repairs (n = 386) done in our institution as open sublay mesh reinforcement, partially requiring component separation (CS), receiving iNPWT in selected cases based on single surgeon experience. Pre- and perioperative data included patient and hernia characteristics as well as the employed mesh sizes. Postoperative follow-up (median 38.5 months [interquartile range: 23.4, 53.3]) extended beyond patient dismissal and included the rate of re-admission due to wound healing disorders. The primary outcome was the incidence of surgical site occurrences (SSO). Secondary endpoints included wound-related readmissions, reoperations and recurrences. Patients were matched based on propensity scores in a 1:1 ratio. Propensity scores were calculated based on five preoperative variables, including sex, body-mass-index, American Society of Anesthesiology classification, recurrent hernia repair and operation technique, to identify significant parameters. The rate of SSO was 12% (n = 46) for all operated cases, and the rate of surgical site infection (SSI) was 8.8% (n = 34). In the subgroup of CS (n = 40), the rate increased to 15% (n = 6). The usage of iNPWT (n = 54) led to an in-hospital SSO rate of 14.8% (n = 8) but increased to 33.3% (n = 18) when including the re-admission rate. The SSI rate for the iNPWT cohort was 14.8% (n = 8) with a consecutive need for reoperation (Clavien-Dindo IIIb) in 87.5% (n = 7). In the matched-pair analysis, the hernia-size and mesh-size were the main risk factors for SSO. The use of iNPWT significantly reduced this statistical effect (p = 0.405). In a large and representative patient cohort, we were able to demonstrate that the advantage of iNPWT used after complex abdominal wall repair does not come first hand. Especially in the follow-up, we found a relevant increase in wound healing problems after dismissal. To proof the benefit of iNPWT in these heterogeneous patients, we could identify hernia size and mesh size as individual risk factors that were nihilated by the use of iNPWT. We found it to be favourable to use iNPWT when mesh-size exceeded 450 cm² .

Alterations in the mechanical, chemical and biocompatibility properties of low-cost polyethylene and polyester meshes after steam sterilization

Introduction

In Africa and other Low Resource Settings (LRS), the guideline-based and thus in most cases mesh-based treatment of inguinal hernias is only feasible to a very limited extent. This has led to an increased use of low cost meshes (LCMs, mostly mosquito meshes) for patients in LRS. Most of the LCMs used are made of polyethylene or polyester, which must be sterilized before use. The aim of our investigations was to determine changes in the biocompatibility of fibroblasts as well as mechanical and chemical properties of LCMs after steam sterilization.

Material and methods

Two large-pored LCMs made of polyester and polyethylene in a size of 11 x 6 cm were cut and steam sterilized at 100, 121 and 134 °C. These probes and non-sterile meshes were then subjected to mechanical tensile tests in vertical and horizontal tension, chemical analyses and biocompatibility tests with human fibroblasts. All meshes were examined by stereomicroscopy, scanning electron microscopy (SEM), LDH (cytotoxicity) measurement, viability testing, pH, lactate and glycolysis determination.

Results

Even macroscopically, polyethylene LCMs showed massive shrinkage after steam sterilization, especially at 121 and 134 °C. While polyester meshes showed no significant changes after sterilization with regard to deformation and damage as well as tensile force and stiffness, only the unsterile polyethylene mesh and the mesh sterilized at 100 °C could be tested mechanically due to the shrinkage of the other specimen. For these meshes the tensile forces were about four times higher than for polyester LCMs. Chemical analysis showed that the typical melting point of polyester LCMs was between 254 and 269 °C. Contrary to the specifications, the polyethylene LCM did not consist of low-density polyethylene, but rather high-density polyethylene and therefore had a melting point of 137 °C, so that the marked shrinkage described above occurred. Stereomicroscopy confirmed the shrinkage of polyethylene LCMs already after sterilization at 100 °C in contrast to polyester LCMs. Surprisingly, cytotoxicity (LDH measurement) was lowest for both non-sterile LCMs, while polyethylene LCMs sterilized at 100 and 121 °C in particular showed a significant increase in cytotoxicity 48 hours after incubation with fibroblasts. Glucose metabolism showed no significant changes between sterile and non-sterile polyethylene and polyester LCMs.

Conclusion

The process of steam sterilization significantly alters mechanical and structural properties of synthetic hernia mesh implants. Our findings do not support a use of low-cost meshes because of their unpredictable properties after steam sterilization.

Intraoperative Assessment of Gastric Sleeve Oxygenation Using Hyperspectral Imaging in Esophageal Resection: A Feasibility Study

Introduction

Sufficient tissue oxygenation is essential for anastomotic healing in visceral surgery. Hyperspectral imaging (HSI) is a noncontact, noninvasive technique for clinical assessment of tissue oxygenation in real time.

Methods

In this case series, HSI was used in 4 patients who were admitted for either esophageal cancer or cardiac carcinoma (AEG type I or II). Thoraco-abdominal surgical esophageal resection was performed after staging and neoadjuvant therapy. Intraoperative oxygenation of superficial (StO₂) and underlying tissue (NIR perfusion index) of the gastric sleeve were studied intrathoracic by means of the TIVITA® Tissue HSI camera. This was performed prior to esophagogastric anastomosis. The postoperative course, especially in view of surgical complications, was recorded.

Results

Assessment of StO₂ and NIR perfusion index was performed in 4 regions of interest per gastric sleeve, aboral and oral of the clinically determined resection line. It allowed the fast quantification of gastric oxygenation prior gastroesophageal anastomosis. Median StO₂ aboral of the determined resection line was 69%, while median StO₂ in the oral part of the gastric sleeve was found at 53%. In contrast, the median NIR perfusion index was similar aboral (80) and oral (82) of the resection line. In none of the 4 studied patients, an anastomotic failure appeared.

Discussion/Conclusion

This report suggests that HSI is a feasible technique for intraoperative assessment of tissue oxygenation before gastroesophageal anastomosis and might reduce the incidence of anastomotic failure in the gastrointestinal tract.

Quality of Life after Complex Abdominal Wall Reconstruction

Background

Component separation (CS) for tension-free approximation of fascial edges is the established technique for the repair of large ventral hernias mostly regarding midline defects. Recent studies suggest lower complication rates following a modified version of this technique using a partially endoscopic-assisted approach, whereas little is known about the quality of life (QoL) in the long-term evaluation of these patients.

Methods

A retrospective study and analysis of patients undergoing hernia repair using an open CS (OCS) and endoscopically assisted CS (ECS) technique, respectively, from 2011 to 2016 at the Rostock University Medical Center. Patients underwent a mesh-based sublay reinforcement following a distinct CS with closure of the linea alba. Patient characteristics, technical details, and short-term postoperative outcomes were determined by a physician chart review. A health-related QoL survey (EQ-5D) including a pain assessment was evaluated at a median of 19.5 months postoperatively.

Results

Thirty-five patients had a CS: 25 OCS and 10 ECS. Perioperative variables were comparable except for the median defect size (169 cm² OCS vs. 86 cm² ECS; p < 0.05) and maximum width of hernia (25 vs. 13 cm). Hospitalization lasted 16.6 days in the OCS group and 7.9 days in the endoscopic group (p = 0.04). Wound complications occurred in 24% of OCS and 10% of ECS patients.

Conclusions

Patients in the ECS group had a shorter hospital stay and less minor and major wound complications. These advantages led to a faster recovery directly affecting the QoL in the ECS group. This effect diminishes in the long-term follow-up with a positive trend towards the OCS technique.

[Autopsies for anatomical teaching and training in clinical forensic medicine]

BACKGROUND

Clinical forensic medicine does not only entail examination of patients after physical violence but also the option of clinical autopsies, e.g. after non-notifiable complications of medical interventions, after fatalities closely following medical interventions or fatalities as a result of injuries when the public prosecutor decides not to order a medicolegal autopsy. Based on this routine the Institute of Forensic Medicine at the University of Rostock offers a training course in topographical anatomy to physicians for further training in interventional and surgical disciplines.

METHODS

At the beginning of autopsies the participants can explore the approaches of interventional puncture techniques as well as surgical techniques and the basic topographical anatomy in small groups of 2-4 persons under the supervision of forensic examiners. The format is essentially oriented to the early further training period but fulfils the requirements for the exploration of complex operative techniques. The course was adapted for physicians and offered separately to students. The explorations are performed manually or by support with autopsy instruments.

RESULTS

The courses offer an ideal room for individual, discipline-specific topics and result in a great benefit for all participants. A statistical assessment can only be achieved with a larger number of participants.

CONCLUSION

Making autopsy rooms available for teaching and further training represents an additional feature to the profile of clinical forensic medicine. Lessons in topographical anatomy provide a great benefit for patient safety. It seems to be important to offer the opportunity to address individual interests in a closed meeting to consolidate skills and abilities in a non-judgemental environment. The post-mortem examiners have to ensure that the autopsy is carried out lege artis. Basic ethical principles and all regulations from an accredited scope have to be adhered to.

[Inguinal Hernia Repair According to Desarda - Implementation of a Mesh-Free Method in a German University Hospital]

Inguinal hernia repair shows a clear tendency towards mesh-based as well as laparoscopic approaches. This is widely reflected in data-based statistics and guidelines. In contrast we have initiated and hereby illustrate the surgical method according to Desarda using autologous fascia to repair inguinal hernia.

[Loss of domain-a surgeon's challenge. Surgical approach to an enormous scrotal hernia]

We report on the one-stage procedure surgical approach to an enormous scrotal hernia bearing the whole small bowel and part of the large bowel as a loss of domain situation. Using a mesh-based component separation abdominal wall technique according to Ramirez we managed to retrieve the hernia content into the abdominal cavity allowing reduction of the resulting intra-abdominal pressure. We present our surgical approach in detail and report on the postoperative process based on focused intensive care surveillance and specific surgical complication management leading to hospital discharge of the patient on postoperative day 57.

[Treatment of a subsequently detected, iatrogenic colonic perforation via minimal-invasive rendezvous procedure]

Laparoscopic surgery as primary therapeutical option for iatrogenic colonic perforation after colonoscopy can be complemented by intraoparative colonoscopy in order to detect and treat even difficult accessible lesions. Via the presented method minimal invasisve detection and therapy of perforation can be conducted safely and can lead to reduction of morbidity.

For she that hath, to her shall be given…Implications of flowering in Anemone nemorosa L

We looked for life-history trade-offs between flowering, vegetative growth and somatic maintenance in the common woodland herb Anemone nemorosa. A. nemorosa forms a horizontal rhizome system consisting of previously formed annual segments and terminated by a flowering or non-flowering shoot. Resources acquired by the aboveground parts are used for flowering, seed production, storage and growth of the annual segments. Resources stored in the rhizome during the growing period are used for preformation of buds, somatic maintenance between two growing periods and development of aboveground parts in the following spring. We hypothesised that the decision to invest in flower buds depends on the amount of resources stored in the recently formed annual segment. We also hypothesised a trade-off between flowering and segment growth and, finally, as a consequence, we expected individual rhizomes to alternate between the flowering and the non-flowering state. We found that segments producing flower buds were significantly longer than non-flowering segments, indicating that resource level influences the function of the preformed buds. Contrary to our expectations, we found flowering rhizomes produced longer annual segments than non-flowering rhizomes. We suggest the larger leaf area of flowering rhizomes and occasional abortion of flowers or seeds as possible mechanisms behind this pattern. Our study shows that even though the decision to produce a flower bud is taken in another time-frame than that in which the actual flowering and fruiting takes place, an ostensibly inexpedient decision is changed to a neutral or even an advantageous incident.

Trans-interfacial polymerization and matter transport processes in epoxy-alumina nanocomposites visualized by scanning Brillouin microscopy

The structural developments in the vicinity of the interface between the reactants of an epoxy are investigated using time- and space-resolved scanning Brillouin microscopy. The hypersonic profile across the phase boundary evolves with strong spatial asymmetry and exhibits erratic behavior within the resin-rich region, which is attributed to a complex interplay between matter transport, dissolution, polymerization, and molecular unravelling process. The presence of alumina nanoparticles in the resin changes the character of these matter transport and reaction processes significantly. On the one hand, the nanoparticles act as transport barriers, hindering the mixing of the reactive components; on the other hand they seem to have a catalytic influence on the epoxy polymerization under certain circumstances. Their transport against gravity is tentatively attributed to gradients in surface tension.

Influence of Leaving-Group Electronic Effect on alpha-Chymotrypsin: Catalytic Constants of Specific Substrates

Rate constants and binding constants for the alpha-chymotrypsin-catalyzed hydrolysis of N-acetyltyrosine, tryptophan, and phenylalanine anilides are presented. Both k(cat) and K(m) are independent of electronic effects in the substrate over a range of 9.8 orders of magnitude (as measured by pK of the leaving group). Similarly, K(m) is independent of charge and orientation about the alpha-carbon for various substrates and pseudo-substrates. These results are not consistent with the pretransition state protonation hypothesis; instead, they are discussed in terms of a tetrahedral intermediate that is thermodynamically less stable than the Michaelis complex.

Unexpectedly high genetic variation in large unisexual clumps of the subdioecious plant Honckenya peploides (Caryophyllaceae)

Honckenya peploides is a subdioecious dune plant that reproduces both sexually and by clonal growth. In northwest Spain this species was found to exhibit an extreme spatial segregation of the sexes, and our objective was to investigate genetic variation in unisexual clumps. Genetic variation was studied in six unisexual clumps of H. peploides, three of them exclusively composed of males and three exclusively female. In total, 193 samples were analysed using isozyme analysis and 80 samples were analysed using two AFLP primer combinations. Both techniques revealed considerably high genetic diversity (average proportion of distinguishable genotypes: 0.22 for isozymes and 0.36 for AFLP; average Simpson's D: 0.65 for isozymes and 0.68 for AFLP). Our results show that, in spite of clonal growth, each unisexual clump consists of different genotypes. Genetic diversity within clumps is similar for both sexual morphs. Reasons for unisexuality of the clumps are discussed.

Concentration and temperature dependence of the refractive index of ethanol-water mixtures: influence of intermolecular interactions

The temperature and concentration dependence of the refractive index, nD(x, T), in ethanol-water mixtures agrees with previous data in the ethanol-rich concentration range. The refractive index versus concentration x determined at 20 degrees C shows the expected maximum at about 41 mol% water (22 mass% water). The temperature derivative of the refractive index, dnD/dT, shows anomalies at lower water concentrations at about 10 mol% water but no anomaly at 41 mol% water. Both anomalies are related to intermolecular interactions, the one in nD seems to be due to molecular segregation and cluster formation while the origin of the second one in dnD/dT is still not clear.

Phase locking of a 1.5 Terahertz quantum cascade laser and use as a local oscillator in a heterodyne HEB receiver

We demonstrate for the first time the closure of an electronic phase lock loop for a continuous-wave quantum cascade laser (QCL) at 1.5 THz. The QCL is operated in a closed cycle cryo cooler. We achieved a frequency stability of better than 100 Hz, limited by the resolution bandwidth of the spectrum analyser. The PLL electronics make use of the intermediate frequency (IF) obtained from a hot electron bolometer (HEB) which is downconverted to a PLL IF of 125 MHz. The coarse selection of the longitudinal mode and the fine tuning is achieved via the bias voltage of the QCL. Within a QCL cavity mode, the free-running QCL shows frequency fluctuations of about 5 MHz, which the PLL circuit is able to control via the Stark-shift of the QCL gain material. Temperature dependent tuning is shown to be nonlinear, and of the order of -16 MHz/K. Additionally we have used the QCL as local oscillator (LO) to pump an HEB and perform, again for the first time at 1.5 THz, a heterodyne experiment, and obtain a receiver noise temperature of 1741 K.

Influence of Al(2)O(3) nanoparticles on the isothermal cure of an epoxy resin

The influence of Al(2)O(3) nanoparticles on the curing of an epoxy thermoset based on diglycidyl ether of bisphenol A was investigated using temperature-modulated differential scanning calorimetry (TMDSC) and rheology. Diethylene triamine was used as a hardener. TMDSC not only allows for a systematic study of the kinetics of cure but simultaneously gives access to the evolution of the specific heat capacities of the thermosets. The technique thus provides insight into the glass transition behaviour of the nanocomposites and hence makes it possible to shed some light on the interaction between the nanoparticles and the polymer matrix. The Al(2)O(3) fillers are shown to accelerate the growth of macromolecules upon isothermal curing. Several mechanisms which possibly could be responsible for the acceleration are described. As a result of the faster network growth chemical vitrification occurs at earlier times in the filled thermosets and the specific reaction heat decreases with increasing nanoparticle concentration. Rheologic measurements of the zero-shear viscosity confirm the faster growth of the macromolecules in the presence of the nanoparticles.

Second order elasticity at hypersonic frequencies of reactive polyurethanes as seen by generalized Cauchy relations

The non-equilibrium process of polymerization of reactive polymers can be accompanied by transition phenomena like gelation or the chemical glass transition. The sensitivity of the mechanical properties at hypersonic frequencies-including the generalized Cauchy relation-to these transition phenomena is studied for three different polyurethanes using Brillouin spectroscopy. As for epoxies, the generalized Cauchy relation surprisingly holds true for the non-equilibrium polymerization process and for the temperature dependence of polyurethanes. Neither the sol-gel transition nor the chemical and thermal glass transitions are visible in the representation of the generalized Cauchy relation. Taking into account the new results and combining them with general considerations about the elastic properties of the isotropic state, an improved physical foundation of the generalized Cauchy relation is proposed.

Chemically induced transition phenomena in polyurethanes as seen from generalized mode Grüneisen parameters

Many phenomenological properties of reactive polymers like polyurethanes increase or decrease continuously in the course of the curing process before saturating at the end of the chemical reaction. This holds true for instance for the mass density, the refractive index, the chemical turnover and the hypersonic properties. The reason for this monotone behaviour is that the chemical reaction behaves like a continuous succession of irreversible phase transitions. These transitions are superposed by the sol-gel transition and possibly by the chemically induced glass transition, with the drawback that the latter two highlighted transitions are often hidden by the underlying curing process. In this work we propose generalized mode Grüneisen parameters as an alternative probe for elucidating the polymerization process itself and the closely related transition phenomena. As a model system we use polyurethane composed of a diisocyanate and varying ratios of difunctional and trifunctional alcohols.

Genealogy, morphology and fitness of spontaneous hybrids between wild and cultivated chicory (Cichorium intybus)

Crop species are known to hybridize spontaneously with wild relatives, but few studies have characterized the performance of hybrids at various genealogies, life stages and environments. A group of cultivar-like individuals and potential hybrids were observed in a roadside population of wild chicory plants in Denmark. Seeds were collected from all reproductive plants and grown in a common garden experiment, and their morphological and genetic compositions were analysed. Intermediate plants were identified as hybrids and comprised various backcross and F(n) combinations. A genotypic hybrid index (HI), spanning from wild-like to cultivar-like, was highly correlated to a morphological index. Plant survival, growth and reproduction were evaluated and compared to the genotypic HI. Overall, cultivar-like and intermediate plants grew larger than wild-like plants, flowered longer, and produced more flowers and seeds. The common garden included a nutrient gradient. At higher nutrient levels, intermediate and cultivar-like plants produced more flowers and seeds than wild-like plants, whereas this effect was less pronounced at lower nutrient levels. During winter, small rodents consumed roots of cultivar-like and intermediate plants preferentially. Thus, cultivated and wild chicory are able to hybridize spontaneously, producing hybrid offspring of several generations that may reproduce more effectively than their wild parent, but herbivory and poor environmental conditions may negatively affect their fitness.

Mechanical and Structural Properties of a Novel Hybrid Heart Valve Scaffold for Tissue Engineering

Hybrid heart valve scaffolds were fabricated from decellularized porcine aortic heart valve matrices and enhanced with bioresorbable polymers using different protocols: (i) dip coating of lyophilized decellularized matrices, and (ii) impregnation of wet decellularized matrices. The following polymers were evaluated: poly(4-hydroxybutyrate) and poly(3-hydroxybutyrate-co4-hydroxybutyrate). Tensile tests were conducted to assess the biomechanical behavior of valve leaflet strips. Suture retention strength was evaluated for the adjacent conduit. A pulse duplicator system was used for functional testing of the valves under physiological systemic load conditions. The properties of the hybrid structures were compared with native, decellularized, and glutaraldehyde-fixed specimens. Mechanisms of the polymer impregnation process were studied with IR spectroscopy, fluorescent microscopic imaging, and SEM. Altogether this study demonstrates the feasibility and improved biomechanical function of a novel hybrid heart valve scaffold for an application in tissue engineering.

[Sacral osteochondrosis dissecans in a Bernese Mountain Dog: diagnosis and treatment]

A 18-month-old female Bernese Mountain Dog with chronic pain at jumping, extension of the right hind leg and paresis of the tail was referred to the Neurological Service of the Veterinary Hospital of the University of Zurich. Upon radiological examination a mineralised fragment at the dorsal aspect of the endplate of S1 was detected. The diagnosis of Osteochondrosis dissecans was confirmed by linear and computed tomography as well as histologic examination of the fragment, which was surgically removed. Preoperative imaging allowed a minimal surgical approach using a unilateral, modified dorsal laminectomy. Outcome was evaluated by neurological reevaluation and a CT scan performed 6 months after surgery.

First experiences with multidetector CT in traumatized children

INTRODUCTION

The aim of this study was to describe and discuss first experiences with multidetector CT (MDCT) in the assessment of traumatized children.

MATERIAL AND METHODS

Since the implementation of a MDCT scanner in April 2002, 85 children (31 girls, 54 boys with a mean age of 9.2 years) consecutively underwent MDCT (Siemens, Erlangen, Germany) with different protocols depending on age, weight, trauma mechanism and clinical presentation. In all patients in whom pathology was suspected, multiplanar reformations (MPR) in coronal and or sagittal orientation was performed. Examinations were evaluated by two radiologists retrospectively and in consensus.

RESULTS

In 55 (65%) children, a MDCT solely of the head was performed, in 46 there was no pathology found. In six (7%), head and facial bones were scanned. Head and abdomen was examined in two (2%), in two (2%) the abdomen only and in one (1%) the pelvis solely. Scans of the spine were obtained in seven (8%) children. A thorax and abdomen examination only was obtained in one (1%) child each. In 11 (13%) children, a polytrauma protocol was performed. In all patients, the time of examination did not exceed 17 min, including setup time. All children survived at the writing of this report.

CONCLUSION

MDCT was promising in the management of traumatized children and seems to shorten the necessary time to reach diagnosis and to initiate life-saving treatment.

What can morphology and isozymes tell us about the history of the Dryas integrifolia-octopetala complex?

An earlier study of the morphological variation in the circumpolar genus Dryas in Greenland revealed that populations in east Greenland are highly variable and this variation was interpreted as a hybrid zone between D. octopetala and D. integrifolia. It was proposed that populations of Dryas in east Greenland immigrated postglacially from Svalbard. The purpose of our study was to investigate the population structure of the Dryas integrifolia-octopetala complex using a combination of morphological and genetic characters. Populations of Dryas were sampled in Greenland, Svalbard, Iceland and north Scandinavia (Sweden). The morphological traits clearly separated west Greenland from Svalbard, Iceland and north Scandinavia. A large number of individuals from east Greenland and some from north Greenland could be interpreted as hybrids between the morphs. The genetic pattern was, however, partly different as the greatest amount of differentiation among regions was found between west and north Greenland (FRT = 0.65). The highest degree of genetic variation appeared within east Greenland. This was in accordance with the putative hybrid origin of the populations, as concluded based on the morphological results. The total amount of genetic differentiation found among the six regions (FRT = 0.61) was larger than between the two species (FRT = 0.44). The genetic pattern matched the proposed postglacial migration routes.

Flupenthixol versus risperidone: subjective quality of life as an important factor for compliance in chronic schizophrenic patients

OBJECTIVE

The primary aim of this paper was to compare the effects of flupenthixol and risperidone on subjective quality of life and attitude towards medication in chronic schizophrenic patients with mainly negative symptoms. In a spectrum ranging from its typical end "haloperidol" to its atypical end "clozapine", flupenthixol has typical and atypical characteristics.

METHODS

The effects of flupenthixol versus risperidone were investigated in a multicenter, double-blind trial, whereas subjective quality of life was assessed by means of the EuroQuol-Visual Analogue Scale and the patient satisfaction questionnaire. The attitude towards medication was assessed by means of the Drug Attitude Inventory-30 (DAI-30).

RESULTS

Mean daily dose of study medication was 6.6 (SD 2.9) mg/day flupenthixol and 3.6 (SD 1.2) mg/day risperidone. Both groups showed a significant improvement regarding subjective quality of life and positive attitude towards medication. Especially the categories "control of their thoughts", concentration and "feeling better in general" ameliorated in both groups. In the flupenthixol group, the "ability to cope with stress", "feel more relaxed" and the "ability to achieve something" improved significantly more than in the risperidone group.

CONCLUSIONS

(1) The spectrum of schizophrenia can be treated effectively with different neuroleptic treatments. (2) Flupenthixol especially improves the ability to cope with stress, the ability to achieve something and feeling more relaxed. (3) Subjective quality of life significantly increased with no difference between the groups.

Fuzzy logic-based tumor marker profiles improved sensitivity of the detection of progression in small-cell lung cancer patients

Tumor markers were used for disease monitoring in small-cell lung cancer patients. The aim of this study was to improve diagnostic efficiency in the detection of tumor progression in small-cell lung cancer patients by using fuzzy logic modeling in combination with a tumor marker panel (NSE, ProGRP, Tumor M2-PK, CYFRA 21-1, and CEA). Thirty-three consecutive small-cell lung cancer patients were included in a prospective study. The changes in blood levels of tumor markers and their analysis by fuzzy logic modeling were compared with the clinical evaluation of response versus non-response to therapy. Clinical monitoring was performed according to the standard criteria of the WHO. Tumor M2-PK was measured in plasma with an ELISA, all other markers were measured in sera. At 90% specificity, clinically detected tumor progression was found by the best single marker, NSE, in 32% of all cases. A fuzzy logic rule-based system employing a tumor marker panel increased the sensitivity significantly (P>0.0001) in small-cell carcinomas to 67% with the threemarker combination NSE/ProGRP/Tumor M2-PK and to 56% with the best two-marker combination ProGRP/Tumor M2-PK, respectively. An improvement of sensitivity was also observed using the two-marker combination of ProGRP/NSE (sensitivity 49%) or NSE/Tumor M2-PK (sensitivity 52%). The fuzzy classifier was able to detect a higher rate of progression in small-cell lung cancer patients compared with the multiple logistic regression analysis using the marker combination NSE/ProGRP/Tumor M2-PK (sensitivity 44%; AUC=0.76). With the fuzzy logic method and different tumor marker panels (NSE, ProGRP and Tumor M2-PK), a new diagnostic tool for the detection of progression in patients with small-cell lung cancer is available.

Endothelin-1 and vasopressin plasma levels are not associated with the insertion/deletion polymorphism of the human angiotensin I-converting enzyme gene in patients with coronary artery disease

The objective was to investigate whether the renin-angiotensin (RA) system and related peptides endothelin-1 (ET-1) and vasopressin (VP) influence the development of coronary artery disease (CAD). Angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) gene polymorphism has been associated with the risk of CAD. The ACE I/D polymorphism determines ACE activity, but plasma levels of other RA system components remain unchanged. However, ET-1 and VP production could be increased by RA system-dependent stimulation, continually promoted by paracrine stimulation and sustained by neointimal growth. ET-1 and VP have not been associated with the ACE I/D polymorphism so far. The present study investigated the association of the ACE I/D polymorphism with plasma concentrations of ET-1 and VP, as well as with renin, angiotensin-II (AT-II) and ACE activity in 98 Caucasian individuals with CAD. ACE I/D polymorphism showed no association with plasma levels of VP, ET-1, AT-II or renin. These parameters were also not associated taking into consideration different patient variables, such as diabetes mellitus, hypertension or severity of CAD. Only plasma ACE activity was associated with the D allele. In conclusion, the ACE I/D polymorphism could not be related to plasma concentrations of VP, ET-1, renin or AT-II, but as previously demonstrated, it could only be related to ACE activity in patients with CAD. Differences in ACE activity between ACE I/D genotype subgroups are probably compensated within the RA system itself or within non-ACE pathways, so that plasma concentrations of the related peptides ET-1 and VP remain unaffected.

Color coded duplex sonography of inguinal vessels in i.v. drug addicts

BACKGROUND

During recent years increasing numbers of intravenous drug addicts with severe damage to the groin vessels were examined in our angiological ultrasound laboratory. The value of color duplex sonography for the clinical evaluation of these findings is the subject of the present study.

PATIENTS AND METHODS

Over the course of six years every drug addict admitted to our hospital who either complained of pain or discomfort in the inguinal region or showed conspicuous clinical findings in this area was examined in our ultrasound laboratory. First by B-mode, the diameter, wall structure and compressibility of the vessels were evaluated and the surrounding tissue was checked for abnormalities. Then the blood flow of the femoral vessels was examined by color coded duplex. If an abscess was suspected, a computed tomography of the groin was obtained before surgery in most cases.

RESULTS

A total number of 77 patients was examined with pathologic results in all cases. The most frequent finding was venous thrombosis: In 63 patients complete thrombotic occlusion of the femoral vein at the injection site was observed. We registered 14 partial thromboses. 30 patients showed vessel wall alterations to variable extents in which 23 cases referred to veins and 10 cases to arteries. 7 patients showed an occlusion of the femoral artery. In 4 patients we found a false aneurysm and 3 had an arteriovenous fistula. Chronic tissue alterations were present to a certain extent in all cases rendering evaluation frequently difficult. Especially problematic to evaluation were those 34 patients where one or more surgical interventions had been performed previously. The results of an additional computed tomography had little effect on the therapeutic decisions. In 11 patients an abscess incision had to be done during the course of their hospital stay.

CONCLUSION

Extensive damage of the groin vessels is seen in i.v. drug addicts. There is no other patient group with such a diversity of different findings. In almost every case these findings involve veins and arteries as well as the surrounding tissues.

Activation and deactivation kinetics of alpha 2A- and alpha 2C-adrenergic receptor-activated G protein-activated inwardly rectifying K+ channel currents

Although G protein-coupled receptor-mediated signaling is one of the best studied biological events, little is known about the kinetics of these processes in intact cells. Experiments with neurons from alpha(2A)-adrenergic receptor knockout mice suggested that the alpha(2A)-receptor subtype inhibits neurotransmitter release with higher speed and at higher action potential frequencies than the alpha(2C)-adrenergic receptor. Here we investigated whether these functional differences between presynaptic alpha(2)-adrenergic receptor subtypes are the result of distinct signal transduction kinetics of these two receptors and their coupling to G proteins. alpha(2A)- and alpha(2C)-receptors were stably expressed in HEK293 cells at moderate ( approximately 2 pmol/mg) or high (17-24 pmol/mg) levels. Activation of G protein-activated inwardly rectifying K(+) (GIRK) channels was similar in extent and kinetics for alpha(2A)- and alpha(2C)-receptors at both expression levels. However, the two receptors differed significantly in their deactivation kinetics after removal of the agonist norepinephrine. alpha(2C)-Receptor-activated GIRK currents returned much more slowly to base line than did alpha(2A)-stimulated currents. This observation correlated with a higher affinity of norepinephrine at the murine alpha(2C)- than at the alpha(2A)-receptor subtype and may explain why alpha(2C)-adrenergic receptors are especially suited to control sympathetic neurotransmission at low action potential frequencies in contrast to the alpha(2A)-receptor subtype.

HLA-antibody testing: the immune phagocytosis inhibition test is superior to the PRA-STAT and NIH lymphocytotoxic test with respect to specificity

We compared the specificity and sensitivity of four different methods for the detection of antibodies specific for HLA antigens. The NIH version of the complement-dependent cytotoxic test (CDC) was used as the gold standard to which we compared two Fcgamma receptor (FcgammaR)-dependent immune phagocytosis inhibition tests (IPI) and one commercial enzyme-labelled immunosorbent assay (ELISA) with soluble HLA class I-antigen preparations bound to the plate (PRA-STAT). Both IPI tests are based on the fact that HLA-antibodies specifically bind to antigens on the monocyte surface via their Fab portion, and in so doing block a neighbouring FcgammaR with their Fc region. This blockade prevents phagocytosis of IgG-coated red blood cells (RBCs), which can be measured either microscopically (IPIm) or photometrically (IPIp). The four assays were used in blind tests on 20 human alloantisera or monoclonal antibodies with known HLA-antigen reactivities. Additionally, two monoclonal antibodies and one human serum were titrated to elucidate the sensitivity of each test. After all tests were completed, the identities of the samples were disclosed. Both IPI methods detected and identified all clinically relevant HLA class I and class II specific antibodies. In contrast, the CDC was not able to detect noncytotoxic HLA-antibodies and HLA class II specific antibodies; however, it detected clinically insignificant IgM lymphocytotoxins. The PRA-STAT assay enabled identification of all cytotoxic and noncytotoxic IgG antibodies with specificity for HLA-class I antigens. With respect to sensitivity, the CDC and the IPI methods were superior to the PRA-STAT. These facts demonstrate the advantage of IPI methods in the detection of clinically relevant HLA-antibodies.

Mortality in affective disorders

BACKGROUND

To investigate the mortality rates in affective disorders due to unnatural and natural causes with respect to illness subtype and social-demographic features.

METHODS

Mortality data were determined from a prospective study of 354 outpatients with affective disorders during a follow-up period of 5 years. Death from natural and unnatural causes was compared to sex- and age-specific expectations in the general population. Standardized mortality rates (SMR) in diagnostic subgroups and the influence of social-demographic features were investigated.

RESULTS

The observed 30 deaths represented nearly three times (SMR, 2.9) the number expected on the basis of age- and sex-standardized reference population rates. Death from natural causes occurred with the same rate as expected (SMR, 1.0), death from unnatural causes was 28.8 times higher than expected. Women with affective disorders had a considerable high risk to die from unnatural causes (SMR, 47.1). A significant excess of unnatural death was found in all subtypes of affective disorders, particularly in recurrent major depressive episodes (SMR, 46.7).

LIMITATIONS

The sample was restricted in size. Therefore subgroup differences and multiple relationships of risk factors could not be analyzed with high statistical power.

CONCLUSIONS

The results corroborate earlier findings of excess mortality in major affective disorders and strengthen the view that suffering from recurrent major depression confers per se an important biological risk for suicide. Natural causes of death in affective disorders are comparable to expectations from reference populations. Social-demographic characteristics may contribute to an additional risk of premature death by suicide, particularly in women.