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.

The rate of change in declining steroid hormones: a new parameter of healthy aging in men?

Research on healthy aging in men has increasingly focused on age-related hormonal changes. Testosterone (T) decline is primarily investigated, while age-related changes in other sex steroids (dehydroepiandrosterone [DHEA], estradiol [E2], progesterone [P]) are mostly neglected. An integrated hormone parameter reflecting aging processes in men has yet to be identified. 271 self-reporting healthy men between 40 and 75 provided both psychometric data and saliva samples for hormone analysis. Correlation analysis between age and sex steroids revealed negative associations for the four sex steroids (T, DHEA, E2, and P). Principal component analysis including ten salivary analytes identified a principal component mainly unifying the variance of the four sex steroid hormones. Subsequent principal component analysis including the four sex steroids extracted the principal component of declining steroid hormones (DSH). Moderation analysis of the association between age and DSH revealed significant moderation effects for psychosocial factors such as depression, chronic stress and perceived general health. In conclusion, these results provide further evidence that sex steroids decline in aging men and that the integrated hormone parameter DSH and its rate of change can be used as biomarkers for healthy aging in men. Furthermore, the negative association of age and DSH is moderated by psychosocial factors.

Emotional Support, Depressive Symptoms, and Age-Related Alterations in Male Body Composition: Cross-Sectional Findings from the Men's Health 40+ Study

More depressive symptoms and low emotional support have been related to worse body composition. Body composition significantly deteriorates in aging men. Therefore, we aimed to examine whether high emotional support and low depressive symptoms are associated with better body composition and a decelerated age-related deterioration of body composition in aging men. A cross-sectional analysis including 269 self-reporting healthy men aged between 40 and 75 years living in the German-speaking part of Switzerland was conducted. Participants completed questionnaires on emotional support and depressive symptoms. The depression screening instrument was used to form a group with low (N = 225) and moderate (N = 44) depressive symptoms. Body mass index (BMI) and waist-to-hip ratio (WHR) were measured, and cell proportion (CP), fat mass (FM), and water balance (WB) were obtained using bioelectrical impedance analysis. Age-related associations emerged for WHR, CP, FM, and WB, but not for BMI. Emotional support was negatively associated with BMI, WHR, and WB, and only trend-wise with CP and FM. Group comparisons revealed that more depressive symptoms were associated with lower levels of CP and higher levels of WB. Both emotional support and depressive symptoms were significant moderators of the association between age and specific measures of body composition such as CP, FM, and WB. However, after correction for multiple testing for moderation analyses only the moderation effects of depressive symptoms on the association between age and WB and CP remained significant. Low depressive symptoms were associated with a better body composition as well as a decelerated decline in body composition and the role of emotional support acting as a buffer against age-related deterioration of body composition merits further investigation.

[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.

[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.

Psychopathological predictors of suicide in patients with major depression during a 5-year follow-up

OBJECTIVE

It is widely known that the risk of suicide is higher in cases of major depressive disorders in comparison to the general population. The purpose of this study was to examine which psychopathologic symptoms during the index episode are predictors for an increased risk of suicide in the further course of major depression.

METHOD

Mortality data were determined from a prospective study of 280 patients with major depression (DSM-III-R, single episode or recurrent) during a follow-up period of 5 years. The predictive power of different depressive symptoms including psychotic symptoms for suicide risk was investigated.

RESULTS

Patients who committed suicide (N = 16) during the follow-up period had reported significantly more often hypochondriacal preoccupations or delusions (but not delusions or preoccupations of impoverishment, guilt or sin), suicidal thoughts and suicide attempts as well as feelings of severe hopelessness during the index episode than still living patients or patients who had died from natural causes.

CONCLUSION

These symptoms seem to be helpful early predictors for the risk of suicide during the further course of illness. This should be taken into account for suicide prevention in the course of major depression.

The paraoxonase Leu-Met54 and Gln-Arg191 gene polymorphisms are not associated with the risk of coronary heart disease

BACKGROUND

Evidence has been presented that gene polymorphisms (PON54 L/M, PON191 Q/R) of paraoxonase are risk factors of coronary heart disease.

RESULTS

We determined both PON genotypes in 535 male individuals who were free of vascular disease and in 2249 male subjects who underwent coronary angiography, and analysed the relation of both gene variations to CAD and MI. Both gene polymorphisms were in linkage disequilibrium (P<0.0001). Coronary artery disease: the PON54 gene polymorphism was not associated with an increased risk of CAD. In the total sample and also in younger subjects, an association of the PON191 gene variation with the risk of CAD was not detected when the control group of individuals without coronary heart disease was compared with patients with at least one diseased vessel (verified by coronary angiography). In individuals younger than 62 years, a moderate increase in the relative risk of CAD associated with the PON191 R allele (1.45 (1. 08-1.95); P=0.015) were found, when subjects without vessel disease (verified by coronary angiography) were compared with CAD patients. Myocardial infarction: an association of the PON54 gene variation with MI was not detected when the control group of individuals without coronary heart disease were compared with patients with at least one MI. A marginal increase in the risk of MI associated with the PON54 LL genotype (OR 1.27 (1.05-1.51); P=0.011) were detected when patients without MI but with coronary angiography were compared with MI positive patients. Subgroup analyses of low- and high-risk populations did not reveal any association of both PON gene polymorphisms with CAD or MI.

CONCLUSION

The present findings do not strengthen the hypothesis that the paraoxonase gene polymorphisms are independently associated with coronary heart disease indicating that these gene variations are of little usefulness as genetic markers of cardiovascular disease.

Comparison of moclobemide with selective serotonin reuptake inhibitors (SSRIs) on sexual function in depressed adults. The Australian and German Study Groups

OBJECTIVE

To compare the emergent sexual effects of moclobemide and selective serotonin reuptake inhibitors (SSRIs) during acute and maintenance therapy in routine practice.

METHOD

268 patients were evaluated for sexual function at baseline, 6 weeks, 3 and 6 months of treatment using physician ratings and self-rating questionnaires. Patients received moclobemide, an reversible monoamine oxidase A inhibitor (RIMA), or a SSRI (fluoxetine, fluvoxamine, paroxetine, sertraline).

RESULTS

Baseline values were similar in all groups. Incidences of impairments of sexual functioning with treatment, whether clinically relevant or not, were 24.3% with moclobemide and 61.5% with SSRIs (physician ratings), with no significant tolerance to these effects. There was a suggestion of differences between the SSRIs in their specific dysfunctions they cause. SSRIs (21.6% of patients) had about ten times the moclobemide rate (1.9%) of sexual dysfunction reported as adverse events. Antidepressant efficacy was comparable between treatments.

CONCLUSION

In patients for whom sexual function is important or sexual dysfunction is present, moclobemide should be considered a first line antidepressant.

[The value of diffusion-weighted MRT in assessing the bone marrow changes in vertebral metastases]

AIM OF THE STUDY

The aim of the study was the evaluation of the diffusion coefficient (ADC) of vertebral metastasis and regular vertebral bodies with diffusion weighted MRI (DWI). DWI evaluates the tissue-specific molecular diffusion of protons. In tissues with high cell densities (neoplasm) a decreased ADC can be expected due to restricted diffusion according to an exaggerated amount of intra- and intercellular membranes (i.e. diffusion barriers).

METHODS

In 5 breast cancer patients the ADC of both known vertebral metastases and of adjacent regular vertebral bodies were measured with DWI (1.0 T; Phased-Array-Body-Coil; b: 880 and 440 s/mm2).

RESULTS

The ADC of regular vertebral bodies (1.3 +/- 0.23 x 10(-3) s/mm2) was significantly (p < or = 0.0002) higher than in vertebral metastases (0.39 +/- 0.11 x 10(-3) s/mm2).

CONCLUSIONS

These data demonstrate that the ADC can be reliably measured in vertebral bodies. The quantitative evaluation of the ADC in vertebral bodies seems to be an objective and comparable parameter for differentiating malign from benign vertebral tissue.

Frequency and width crossing of two interacting resonances in a microwave cavity

Frequency and width crossing have been observed for two coupled resonances in a microwave cavity. The cavity consisted of two nearly identical rectangular boxes. The boxes were coupled by a slit of variable width. The data are well described by a non-Hermitean S matrix leading to a 2x2 non-Hermitean effective Hamiltonian. The values of the interaction strength |v| for which width crossing and frequency crossing, respectively, were observed, are above and below a critical value |v(c)| for which one expects a joint frequency and width crossing.