Therapeutic approaches of diametaphyseal radius fractures in children

BACKGROUND

There are clear standards for when to operate on both distal epiphyseal and diaphyseal forearm fractures in children. However, paediatric surgeons are often faced with fractures in the transition zone between metaphysis and diaphysis. This aim of the study is to compare different treatment approaches for diametaphyseal forearm fractures, to classify different types of these fractures, and to define further assessment parameters and treatment recommendations.

METHODS

This retrospective study included all patients with diametaphyseal radial fractures who were seen at a paediatric surgery clinic between 01.01.2010 and 31.12.2013. Patients were treated either non-surgically (C) or surgically using bicortical Kirschner wire (BC-KW), intramedullary K-wire (IM-KW), elastic stable intramedullary nailing (ESIN), or combined bicortical and intramedullary K-wire (BCIM-KW).

RESULTS

During the study period, 547 patients presented with forearm fractures of which 88 patients (16%) had a fracture in the diametaphyseal region. The majority of diametaphyseal fractures were greenstick fractures (54.4%) followed by transverse fractures (44.3%). Distal fractures were predominantly treated with bicortical K-wiring (BC-KW, 40.5%) or non-surgically (C, 26.2%). Proximal fractures were treated by ESIN osteosynthesis (50%), followed by IM-KW (30%). Intermediate fractures were just as likely to be treated with one out of the 5 above-mentioned techniques. The ulna was involved in 64 of 88 cases. Depending on the type of fracture, it was treated either by ESIN osteosynthesis or non-surgically. No superior operative technique was identified.

CONCLUSIONS

The description of diametaphyseal fractures as a separate entity is important, because the therapy of these fractures is heterogeneous and challenging. A classification into proximal, intermediate, and distal may be useful in clinical decision-making. Despite the retrospective nature of this study, our data suggest that the use of a K-wire or combined technique BCIM-KW-technique, whenever technically feasible, achieves better radiological results without secondary dislocation. Further prospective studies are needed to provide better guidance to trauma surgeons.

Influence of concomitant medications on the total clearance and the risk for supra-therapeutic plasma concentrations of Citalopram. A population-based cohort study

INTRODUCTION

The main objective of this study was to investigate the influence of the use of multiple medications and other risk factors on citalopram plasma concentrations.

METHODS

A retrospective cohort study with a naturalistic population of 957 patients for whom routine therapeutic drug monitoring (TDM) of citalopram had been requested between 2006 and 2013 was conducted.

RESULTS

Concomitant drugs inhibiting at least 2 different CYP subtypes involved in the metabolism of citalopram decreased statistically significantly the total clearance (Clt). Compared to younger patients over 64-year-old patients had on average a 4.5 times higher risk rate of supra-therapeutic plasma concentrations. However, binary logistic regression showed that age, sex and co-medication accounted only for 26% of the inter-individual variability of citalopram plasma concentrations.

DISCUSSION

Due to pharmacokinetic interactions, citalopram plasma concentrations are often higher than expected with a given dose. Especially in geriatric and often multimorbid patients who are usually prescribed high numbers of concomitant drugs and are at higher risk for adverse drug reactions (ADR), restriction of the maximal dose of citalopram is not sufficient to prevent supra-therapeutic plasma concentrations.

DNA barcodes for species identification in the hyperdiverse ant genus Pheidole (Formicidae: Myrmicinae)

DNA sequencing is increasingly being used to assist in species identification in order to overcome taxonomic impediment. However, few studies attempt to compare the results of these molecular studies with a more traditional species delineation approach based on morphological characters. Mitochondrial DNA Cytochrome oxidase subunit 1 (CO1) gene was sequenced, measuring 636 base pairs, from 47 ants of the genus Pheidole (Formicidae: Myrmicinae) collected in the Brazilian Atlantic Forest to test whether the morphology-based assignment of individuals into species is supported by DNA-based species delimitation. Twenty morphospecies were identified, whereas the barcoding analysis identified 19 Molecular Operational Taxonomic Units (MOTUs). Fifteen out of the 19 DNA-based clusters allocated, using sequence divergence thresholds of 2% and 3%, matched with morphospecies. Both thresholds yielded the same number of MOTUs. Only one MOTU was successfully identified to species level using the CO1 sequences of Pheidole species already in the Genbank. The average pairwise sequence divergence for all 47 sequences was 19%, ranging between 0-25%. In some cases, however, morphology and molecular based methods differed in their assignment of individuals to morphospecies or MOTUs. The occurrence of distinct mitochondrial lineages within morphological species highlights groups for further detailed genetic and morphological studies, and therefore a pluralistic approach using several methods to understand the taxonomy of difficult lineages is advocated.

Spinning a laser web: predicting spider distributions using LiDAR

LiDAR remote sensing has been used to examine relationships between vertebrate diversity and environmental characteristics, but its application to invertebrates has been limited. Our objectives were to determine whether LiDAR-derived variables could be used to accurately describe single-species distributions and community characteristics of spiders in remote forested and mountainous terrain. We collected over 5300 spiders across multiple transects in the Bavarian National Park (Germany) using pitfall traps. We examined spider community characteristics (species richness, the Shannon index, the Simpson index, community composition, mean body size, and abundance) and single-species distribution and abundance with LiDAR variables and ground-based measurements. We used the R2 and partial R2 provided by variance partitioning to evaluate the predictive power of LiDAR-derived variables compared to ground measurements for each of the community characteristics. The total adjusted R2 for species richness, the Shannon index, community species composition, and body size had a range of 25-57%. LiDAR variables and ground measurements both contributed >80% to the total predictive power. For species composition, the explained variance was approximately 32%, which was significantly greater than expected by chance. The predictive power of LiDAR-derived variables was comparable or superior to that of the ground-based variables for examinations of single-species distributions, and it explained up to 55% of the variance. The predictability of species distributions was higher for species that had strong associations with shade in open-forest habitats, and this niche position has been well documented across the European continent for spider species. The similar statistical performance between LiDAR and ground-based measures at our field sites indicated that deriving spider community and species distribution information using LiDAR data can provide not only high predictive power at relatively low cost, but may also allow unprecedented mapping of community- and species-level spider information at scales ranging from stands to landscapes. Therefore, LiDAR is a viable tool to assist species-specific conservation as well as broader biodiversity planning efforts not only for a growing list of vertebrates, but for invertebrates as well.

Tissue Factor-Factor VIIa complex induces cytokine expression in coronary artery smooth muscle cells

OBJECTIVE

Within atherosclerotic lesions Tissue Factor (TF)-Factor VIIa (FVIIa) not only contributes to thrombotic events but also alters vascular remodeling through enhancement of migration. Moreover, the TF-FVIIa-FXa complex activates protease-activated receptors (PAR). TF/FVIIa/PAR-2 signaling has also been shown to promote proliferation and metastasis of tumor cells. Since coagulation factors promote inflammation which plays a major role during atherosclerosis as well as tumor metastasis this study sought to investigate the effects of FVIIa on the inflammatory response in vascular cells.

METHODS/RESULTS

FVIIa induces interleukin-8 (IL-8) and IL-6 in primary smooth muscle cells (SMC), which was correlated to the expression of TF and PAR-2 as shown by immunoassay and qRT-PCR. The effect was dose-dependent and required TF, the proteolytic activity of FVIIa and PAR-2. Secondary effects of downstream coagulation factors were excluded. No proinflammatory FVIIa effect was observed in endothelial cells (EC) and mononuclear cells (MNC), expressing either TF or PAR-2. In atherosclerotic lesions mRNA expression of PAR-1, PAR-2 and IL-8 was elevated compared to healthy vessels indicating a role for PAR-1 and PAR-2 signaling in atherosclerosis.

CONCLUSION

In addition to the procoagulant and promigratory role of the TF-FVIIa complex we identify a proinflammatory role of FVIIa in human SMC dependent on expression of TF and PAR-2 that provides yet another link between coagulation and inflammation.

Shallow phylogeographic structuring of Vimba vimba across Europe suggests two distinct refugia during the last glaciation

Genetic variation and geographical structuring of vimba Vimba vimba were analysed across 26 sites (80 individuals) by means of mtDNA sequences (cyt b gene, mitochondrial control region) to localize hypothesized glacial refugia and to reconstruct postglacial recoloniation routes. Although genetic diversity among sequenced individuals was low, a combined analysis of the two sequenced fragments revealed a western (central and northern Europe: Danube, Elbe and lakes of Sweden) and an eastern clade (eastern Europe: Dnieper-South Bug, Don, Neman). Furthermore, a number of divergent ancestral haplotypes distributed around the Black and Caspian Seas became apparent. Mismatch analyses supported a sudden expansion model for the populations of the western clade between 50 and 10 000 bp. Overall, the study provides strong evidence for a northward and westward expansion of V. vimba from two refugial regions located in the Danubian drainage and the northern Pontic regions respectively.

Divergence times in the termite genus Macrotermes (Isoptera: Termitidae)

The evolution of fungus-growing termites is supposed to have started in the African rain forests with multiple invasions of semi-arid habitats as well as multiple invasions of the Oriental region. We used sequences of the mitochondrial COII gene and Bayesian dating to investigate the time frame of the evolution of Macrotermes, an important genus of fungus-growing termites. We found that the genus Macrotermes consists of at least 6 distantly related clades. Furthermore, the COII sequences suggested some cryptic diversity within the analysed African Macrotermes species. The dates calculated with the COII data using a fossilized termite mound to calibrate the clock were in good agreement with dates calculated with COI sequences using the split between Locusta and Chortippus as calibration point which supports the consistency of the calibration points. The clades from the Oriental region dated back to the early Tertiary. These estimates of divergence times suggested that Macrotermes invaded Asia during periods with humid climates. For Africa, many speciation events predated the Pleistocene and fall in range of 6-23 million years ago. These estimates suggest that savannah-adapted African clades radiated with the spread of the semi-arid ecosystems during the Miocene. Apparently, events during the Pleistocene were of little importance for speciation within the genus Macrotermes. However, further investigations are necessary to increase the number of taxa for phylogenetic analysis.

Unrelated queens coexist in colonies of the termite Macrotermes michaelseni

Relatedness increases the likelihood of cooperation within colonies of social insects. Polygyny, the coexistence of numerous reproductive females (queens) in a colony, is common in mature colonies of the termite Macrotermes michaelseni. In this species, polygyny results from pleometrosis and from several female alates that jointly found a new colony. To explain this phenomenon, it was suggested that only related females cooperate and survive during maturation of colonies. Using multilocus fingerprints as well as microsatellites, we showed that nestmate queens in mature colonies are unrelated. Furthermore, we found that all nestmate queens contributed to the production of steriles. Even in mature colonies, several matrilines of steriles coexist within a colony. Although genetic diversity within colonies may increase the likelihood of conflicts, high genetic diversity may be important for foraging, colony growth, and resistance to disease and parasites.

Frequency, Clinical Significance and Course of Cerebral Ischemic Events after Carotid Endarterectomy Evaluated by Serial Diffusion Weighted Imaging

OBJECTIVES

Neurological deficit defines the outcome of Carotid Endarterectomy (CEA) that is mainly caused by cerebral ischemia. Diffusion-weighted imaging (DWI) is a sensitive method for demonstrating even small ischemic lesions. The aim of this study was to evaluate the frequency, clinical significance and course of ischemic lesions after CEA using serial DWI.

METHODS

DWI was performed within 1 day before and after CEA in 88 patients. Postoperative lesions were analyzed by their quantity, volume and distribution. To differentiate temporary ischemia from definite cerebral infarction (blood brain barrier disruption) all patients with a positive postoperative DWI were reexamined with contrast-enhanced T1-MRI 7-10 days after the procedure. All patients were examined by a neurologist within 2 days before and after CEA.

RESULTS

Two patients showed a postoperative neurological deficit. Postoperative DWI revealed ipsilateral ischemic lesions in 15 patients. In seven of these patients a brain infarction was diagnosed on the T1-MRI during follow-up. A significant correlation between the number of DWI lesions (p=0.031) as well as the volume of DWI lesions (p=0.023) and definite infarction was found. Symptomatic patients preoperatively showed significantly more DWI lesions (p=0.036) and cerebral infarcts (p=0.003).

CONCLUSION

DWI is a sensitive method of demonstrating ischemic events after CEA. The number and volume of DWI lesions after CEA are highly predictive of brain infarction.

[Studies on image quality, high contrast resolution and dose for the axial skeleton and limbs with a new, dedicated CT system (ISO-C-3 D)]

PURPOSE

Evaluation of 3D-CT imaging of the axial skeleton and different joints of the lower and upper extremities with a new dedicated CT system (ISO-C-3D) based on a mobile isocentric C-arm image amplifier.

MATERIAL AND METHODS

27 cadaveric specimes of different joints of the lower and upper extremities and of the spinal column were examined with 3D-CT imaging (ISO-C-3D). All images were evaluated by 3 radiologists for image quality using a semiquantitative score (score value 1: poor quality; score value 4: excellent quality). In addition, dose measurements and measurements of high contrast resolution were performed in comparison to conventional and low-dose spiral CT using a high contrast phantom (Catphan, Phantom Laboratories).

RESULTS

Adequate image quality (mean score values 3 - 4) could be achieved with an applied dose comparable to low-dose CT in smaller joints such as wrist, elbow, ankle and knee. A remarkably inferior image quality resulted in imaging of the hip, lumbar and thoracic spine (mean score values 2 - 3) in spite of almost doubling the dose (dose increased by 85 percent). The image quality of shoulder examinations was insufficient (mean score value 1). Phantom studies showed a high-contrast resolution comparable to helical CT in the xy-axis (9 lp/cm).

CONCLUSION

Preliminary results show, that image quality of C-arm-based CT-imaging (ISO-C-3D) seems to be adequate in smaller joints. ISO-C-3D images of the hip and axial skeleton show a decreased image quality, which does not seem to be sufficient for diagnosing subtle fractures.

[Detection of tibial condylar fractures using 3D imaging with a mobile image amplifier (Siemens ISO-C-3D): Comparison with plain films and spiral CT]

PURPOSE

To analyze a prototype mobile C-arm 3D image amplifier in the detection and classification of experimental tibial condylar fractures with multiplanar reconstructions (MPR).

METHOD

Human knee specimens (n = 22) with tibial condylar fractures were examined with a prototype C-arm (ISO-C-3D, Siemens AG), plain films (CR) and spiral CT (CT). The motorized C-arm provides fluoroscopic images during a 190 degrees orbital rotation computing a 119 mm data cube. From these 3D data sets MP reconstructions were obtained. All images were evaluated by four independent readers for the detection and assessment of fracture lines. All fractures were classified according to the Müller AO classification. To confirm the results, the specimens were finally surgically dissected.

RESULTS

97 % of the tibial condylar fractures were easily seen and correctly classified according to the Müller AO classification on MP reconstruction of the ISO-C-3D. There is no significant difference between ISO-C and CT in detection and correct classification of fractures, but ISO-CD-3D is significant by better than CR.

CONCLUSION

The evaluation of fractures with the ISO-C is better than with plain films alone and comparable to CT scans. The three-dimensional reconstruction of the ISO-C can provide important information which cannot be obtained from plain films. The ISO-C-3D may be useful in planning operative reconstructions and evaluating surgical results in orthopaedic surgery of the limbs.

The niche of higher plants: evidence for phylogenetic conservatism

A species' ecological niche depends on the species' adaptations to its present habitat, but also on the legacy from its ancestors. Most authors argue that such a phylogenetic niche conservatism is of minor importance, although no quantitative analyses across a major taxon is available. Higher plants from central Europe offer a unique opportunity for such an exercise, as the niche positions along various environmental gradients are available for most species. We quantified niche conservatism by two approaches. First, we used a phylogenetic tree and quantified the degree of retention of niches across the tree. Depending on the gradient, the values ranged from 0.43 to 0.22. This was significantly greater than the null expectation. Second, we used a taxonomy and quantified the amount of variance among species that could be explained at higher taxonomic levels. The values ranged from 25 to 72%. Again, this was significantly higher than the null expectation. Thus, both approaches indicated a clear niche conservatism. The distribution of conservatism across taxonomic levels differed considerably among environmental gradients. The differences among environmental gradients could be correlated with the palaeoenvironmental conditions during the radiation of the phylogenetic lineages. Thus, niche conservatism among extant plant species may reflect the opportunities of their ancestors during their diversification.

[Introduction of a new mobile C-arm/CT combination equipment (ISO-C-3D). Initial results of 3-D sectional imaging]

Preclinical evaluation of a new mobile C-arm image amplifier with an option for three-dimensional computed tomography (CT) imaging (prototype Iso-C3D) with respect to high-contrast resolution and possible clinical applications. Cadaveric specimens (n = 30) of different joints of the lower and upper extremities and specimens of the spinal column were examined with the Iso-C3D and evaluated for image quality. In addition, using a high-contrast phantom (Catphan, Phantom Laboratory, Salem, N.Y., USA) and a fracture model of the femoral bone, measurements of high-contrast resolution were performed in comparison to spiral CT. With the exception of the shoulder, all joint regions including the entire spinal column could be examined. Adequate image quality could be achieved in smaller joints such as the wrist, elbow, ankle, and knee, whereas a remarkably decreased image quality was found when imaging the hip as well as the lumbar and thoracic spine. Images of the phantom study and high-contrast fracture model showed a high-contrast resolution comparable to helical CT (9 Lp/cm in xy-axis). In smaller joints, the image quality of the mobile C-arm CT imaging system (Iso-C3D) is comparable to that of helical CT. Image quality in examinations of the hip and lumbar and thoracic spine seems to be sufficient for intraoperative control studies of osteosynthesis. Problems still occur in shoulder examinations.

[3-D imaging with a mobile surgical image enhancement equipment (ISO-C-3D). Initial examples of fracture diagnosis of peripheral joints in comparison with spiral CT and conventional radiography]

To analyze a prototype mobile C-arm image amplifier (Iso-C3D) in the evaluation of different joint fractures of the upper and lower limbs using multiplanar reconstruction (MPR). Different cadaver joint specimens (n = 14) were examined with a prototype (Iso-C3D, Siemens AG, Erlangen, Germany), plain radiographs (CR), and spiral computed tomography (CT). The motorized C-arm provides fluoroscopic images during a 190 degrees orbital rotation computing a 119-mm data cube. These three-dimensional data sets yielded MPR images, which were evaluated by two readers for the detection and extent of fracture lines. Initial data show that fractures were easily depicted and correctly classified on MPR images with the Iso-C3D and that there was no difference between the Iso-C and CT in the detection of fractures. The preliminary results suggest a remarkably good detection of joint fractures with the Iso-C3D. Studies in an adequate number of patients are required to elucidate whether these promising results can also be obtained in a clinical setting.

Demographic and random amplified polymorphic DNA analyses reveal high levels of genetic diversity in a clonal violet

We performed demographic and molecular investigations on woodland populations of the clonal herb Viola riviniana in central Germany. We investigated the pattern of seedling recruitment, the amount of genotypic (clonal) variation and the partitioning of genetic variation among and within populations. Our demographic study was carried out in six violet populations of different ages and habitat conditions. It revealed that repeated seedling recruitment takes place in all of these populations, and that clonal propagation is accompanied by high ramet mortality. Our molecular investigations were performed on a subset of three of these six violet populations. Random amplified polymorphic DNA analyses using six primers yielded 45 scorable bands that were used to identify multilocus genotypes, i.e. putative clones. Consistent with our demographic results and independent of population age, we found a large genotypic diversity with a mean proportion of distinguishable genotypes of 0.93 and a mean Simpson's diversity index of 0.99. Using AMOVA we found a strong genetic differentiation among these violet populations with a PhiST value of 0.41. We suggest that a high selfing rate, limited gene flow due to short seed dispersal distances and drift due to founder effects are responsible for this pattern. Although Viola riviniana is a clonal plant, traits associated with sexual reproduction rather than clonality per se are moulding the pattern of genetic variation in this species.

Transcriptome analysis reveals a role of interferon-gamma in human neointima formation

The most effective immediate cure for coronary stenosis is stent-supported angioplasty. Restenosis due to neointima proliferation represents a major limitation. We investigated the expression of 2435 genes in atherectomy specimens and blood cells of patients with restenosis, normal coronary artery specimens, and cultured human smooth muscle cells (SMCs). Of the 223 differentially expressed genes, 37 genes indicated activation of interferon-gamma (IFN-gamma) signaling in neointimal SMCs. In cultured SMCs, IFN-gamma inhibited apoptosis. Genetic disruption of IFN-gamma signaling in a mouse model of restenosis significantly reduced the vascular proliferative response. Our data suggest an important role of IFN-gamma in the control of neointima proliferation.

Urgent carotid endarterectomy for stroke in evolution

BACKGROUND

Carotid endarterectomy (CEA) is well established as the elective treatment for moderate or severe carotid stenoses with a history of neurologic symptoms. In contrast, the merits of carotid revascularisation performed in emergency in patients with acute stroke or fluctuating neurological deficit remain controversial.

PATIENTS AND METHODS

A total of 445 CEAs were performed on 424 patients for 212 (48%) asymptomatic and 233 (52%) symptomatic carotid stenoses within a 5 years period between January, 1995, and December, 1999. Of the latter, CEA was performed in emergency on 16 patients (3.8%) within 4 to 24 hours after the onset of symptoms. Patients selected for urgent surgery fulfilled the following criteria: acute onset of fluctuating hemispheric neurological symptoms, significant carotid pathology, absence of cerebral hemorrhage, uncompromised vigilance and stable cardiopulmonary conditions. Selected patients presented with a crescendo-TIA (n = 7) or fluctuating neurological deficits (n = 9) corresponding to a contralateral carotid stenosis.

RESULTS

Following CEA, the neurological deficits improved instantaneously to complete recovery in 9 patients. The symptoms of 4 patients improved to non-disabling deficits, remained unchanged in one and worsened in 2 patients from hemihypaesthesia to hemiparesis. 14/16 patients were discharged within 8 days after admission. The neurologic status after discharge did not deteriorate in any of the patients during follow up of 19.3 +/- 13 months, but improved in 4 of the patients.

CONCLUSION

Our retrospective study suggests that rescue CEA may be beneficial for selected patients with stroke in evolution and fluctuating neurological deficits. Careful adherence to selection criteria, intraoperative shunting, intensive care post surgery surveillance and an experienced team are recommended.

Gene expression profiling of human stent-induced neointima by cDNA array analysis of microscopic specimens retrieved by helix cutter atherectomy: Detection of FK506-binding protein 12 upregulation

BACKGROUND

Restenosis due to neointima formation is the major limitation of stent-supported balloon angioplasty. Despite abundant animal data, molecular mechanisms of neointima formation have been investigated on only a limited basis in patients. This study sought to establish a method for profiling gene expression in human in-stent neointima and to identify differentially expressed genes that may serve as novel therapeutic targets.

METHODS AND RESULTS

We retrieved tissue specimens from patients with symptomatic in-stent restenosis using a novel helix cutter atherectomy device. cDNA samples prepared from neointima (n=10) and, as a control, from the media of normal arteries (n=14) were amplified using a novel polymerase chain reaction protocol and hybridized to cDNA arrays. Immunohistochemistry characterized the atherectomy material as neointima. cDNA arrays readily identified differentially expressed genes. Some of the differentially expressed genes complied with expected gene expression patterns of neointima, including downregulation of desmin and upregulation of thrombospondin-1, cyclooxygenase-1, and the 70-kDa heat shock protein B. Additionally, we discovered previously unknown gene expression patterns, such as downregulation of mammary-derived growth inhibitor and upregulation of FK506-binding protein 12 (FKBP12). Upregulation of FKBP12 was confirmed at the protein level in neointimal smooth muscle cells.

CONCLUSIONS

Gene expression patterns of human neointima retrieved by helix-cutter atherectomy can be reliably analyzed by cDNA array technology. This technique can identify therapeutic targets in patients, as exemplified by the findings regarding FKBP12. FKBP12 is the receptor for Rapamycin (sirolimus), which in animal models reduced neointima formation. Our study thus yields a rationale for the use of Rapamycin to prevent restenosis in patients.

[Vascular biological aspects of thrombendarterectomy and alloplastic vascular replacement]

Irrespective of vascular approach and mode of repair any arterial reconstruction is charged by a procedural trauma and a desintegration of the vascular wall in its pathoanatomic structure. A number of specific repair mechanisms are set in motion by cellular and humoral mediators when non-endothelial layers get exposed to the lumen. Platelet deposition, local activation of hemostatic factors, intramural and wall-adjacent thrombus formation as well as subsequent proliferation of myofibroblasts are determinants of this process that may be characterized as a generalized wound healing response resulting in neointima formation. Exemplarily, the valency of endarterectomy and prosthetic grafting in the femoral axis is discussed on the background of recent experience in vascular biology.

[Spiral CT of the abdomen: weight-adjusted dose reduction]

AIM OF THE STUDY

The influence of weight-adjusted current application in spiral CT of the abdomen on noise was investigated in a clinical study.

PATIENTS AND METHODS

In 77 routine abdominal CT investigations (120 kV, 8 mm, pitch 1.5) the patients were divided into three body-weight groups A (< 60 kg), B (60-80 kg), and C (> 80 kg). The tube current was randomized prospectively in low weight group A, either 125 mA or 150 mA, in middle and high weight groups B and C, 150, 175 or 200 mA, with a tube revolution time of one second. The noise was measured in liver, skeleton muscle, fat tissue, and bladder content for evaluation of image quality.

RESULTS

The bodyweight groups differ significantly in noise, e.g., in the liver (150 mA): group A: 15.8 HU, group B: 18.9 HU, group C: 21.5 HU. The increase of tube current (150, 175, 200 mA) within a body weight group resulted in a minor decrease of noise (18.9 HU, 17.6 HU, 17.5 HU, respectively, in group B). There is a good correlation of noise with body weight, body mass index and body cross section, but not with body size.

CONCLUSION

A body weight adjusted reduction of tube current is possible without an increase of noise.

Lysophosphatidic acid and sphingosine 1-phosphate: two lipid villains provoking cardiovascular diseases?

Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (SIP) are potent bioactive lipids with specific and multiple effects on cells of the vessel wall and blood platelets. In this paper we suggest that these lipid molecules are involved in atherogenesis, pathological vasoconstriction, plaque rupture, and intravascular thrombus formation, which leads us to propose new strategies for the prevention and therapy of cardiovascular diseases. The conclusions are hypothetical, in that the studies were so far mainly carried out on isolated cells or cultured cells in vitro and the results were extrapolated to the situation in vivo.