Evaluation of an rDNA Listeria probe for Listeria monocytogenes typing.

A Listeria monocytogenes DNA fragment, identified as part of the 23S rRNA gene and called B17, was used to type 266 L. monocytogenes strains and 43 strains of other Listeria species. Results were compared with those obtained: i) with pBA2 (which consists of a 2.3 kb Bacillus subtilis DNA fragment encoding 16S rRNA, inserted into the HindIII site of pBR322), a probe previously used for Listeria and L. monocytogenes ribotyping, and ii) with DNA macrorestriction profiles analysis. Twenty profiles were identified for L. monocytogenes using pB 17, three of which accounted for 87% of strains. This new rDNA probe had greater discriminatory power for serogroups 1/2 or 3 strains than for serogroup 4 strains. The number of varieties and the discrimination index were higher with this new probe than with pBA2, but DNA macrorestriction patterns analysis gave better discrimination between strains.     

The human amygdala is sensitive to the valence of pictures and sounds irrespective of arousal: an fMRI study

With the advent of studies showing that amygdala responses are not limited to fear-related or highly unpleasant stimuli, studies began to focus on stimulus valence and stimulus-related arousal as predictors of amygdala activity. Recent studies in the chemosensory domain found amygdala activity to increase with the intensity of negative and positive chemosensory stimuli. This has led to the proposal that amygdala activity might be an indicator of emotional arousal, at least in the chemosensory domain. The present study investigated amygdala activity in response to visual and auditory stimuli. By selecting stimuli based on individual valence and arousal ratings, we were able to dissociate stimulus valence and stimulus-related arousal, both on the verbal and the peripheral physiological level. We found that the amygdala was sensitive to stimulus valence even when arousal was controlled for, and that increased amygdala activity was better explained by valence than by arousal. The proposed difference in the relation between amygdala activity and stimulus-related arousal between the chemosensory and the audiovisual domain is discussed in terms of the amygdala''s embedding within these sensory systems and the processes by which emotional meaning is derived.     

Improvement of myocardial function after global hypoxia by protection of the inner mitochondrial membrane

In the present study the hypothesis is tested that hypoxia causes morphological damage to the inner mitochondrial membrane and that this damage can be reversed by modification of the reoxygenated perfusate. Using the working rat heart model, hearts in group I (n = 40) were subjected to a 30 min normothermic, normoxic phase and a 90 min hypoxic phase, followed by 60 min reoxygenation. Hearts in group II (n = 32) were also subjected to a 30 min normoxic and a 90 min hypoxic phase. However, after 30 min of reoxygenation 1.5 mmol/l 2-mercaptopropionylglycine (MPG) was injected in the reoxygenated solution in order to test its ability to improve mitochondrial function. Mitochondrial function was assessed by measuring oxygen uptake (ST3), ST4, respiratory control index (RCI), ADP/O and oxidative phosphorylation rate (OPR). In addition mechanical function (heart rate, aortic and coronary flow, cardiac output, stroke volume) was monitored along with ultrastructural parameters. 90 min of hypoxia caused a deterioration of all parameters with persistent impairment in hemodynamic, morphologic and biochemical functions after 60 min of reoxygenation (group I). The role of the ATP-synthetases in the pathogenesis of oxygen-paradox is discussed. In contrast, the MPG-enriched reoxygenated solution (group II) improved hemodynamics, ultrastructure and mitochondrial function significantly (alpha = 0.05). It is concluded from these data that the ATP-synthetases are damaged during oxygen-deficiency and that MPG may be a useful drug for protecting the inner mitochondrial membranes during reoxygenation.     

Robot guidance for percutaneous minimally invasive placement of pedicle screws for pyogenic spondylodiscitis is associated with lower rates of wound breakdown compared to conventional fluoroscopy-guided instrumentation

Postoperative wound healing can pose a problem in patients undergoing instrumented surgery for pyogenic spondylodiscitis. Robotic guidance allows the minimally invasive placement of pedicle screws in the thoracolumbar spine. We assessed whether using this technique to perform minimally invasive surgery had an impact on wound healing in patients with pyogenic spondylodiscitis when compared to conventional open fluoroscopy-guided surgery. We reviewed charts of 206 consecutive patients who underwent instrumentation for pyogenic spondylodiscitis. The need for wound revision was the primary outcome measure. Patient variables and comorbidities as well as surgical technique (robotic versus fluoroscopy-guided) were analyzed. We also compared fluoroscopy times between the two groups. Multivariate regression analysis was performed to identify predictors of wound breakdown. A total of 206 patients underwent surgery for spondylodiscitis. Robotic surgical assistance was used for percutaneous instrumentation in 47.6% of cases (n = 98). Wound healing problems requiring revision occurred in 30 out of 206 patients (14.6%). Univariate analysis revealed a potential association of wound breakdown with (1) robotic technique, (2) age > 70 years, and (3) the presence of methicillin-resistant Staphylococcus aureus. After multivariate correction however, only robotic technique retained significance with an odds ratio of 0.39 (CI 95% 0.16–0.94; p = 0.035). Wound revision was required in eight out of 98 patients (8.1%) in the robot group and 22/108 (20%) in the conventional surgery group. Fluoroscopy times were significantly lower in the robot group with a mean of 123 ± 86 s in comparison with a mean of 157 ± 99 s in the conventional group (p = 0.014). While initially designed to improve the accuracy of pedicle screw placement, robot-assisted minimally invasive technique had a tangible effect on both radiation exposure and the rate of wound breakdown in patients with pyogenic spondylodiscitis in our large single-center study.     

siRNA and isRNA: two edges of one sword.

RNA interference mediated by small interfering RNAs (siRNA) has emerged as a powerful tool to target specific knockdown of gene expression in cell culture. siRNA is now the gold standard technique to study gene function, and expectations for the development of new target-specific drugs are high. In addition to the gene-silencing activity of siRNA, a number of recent studies have pointed to immunological effects of siRNAs, including the induction of proinflammatory cytokines and type I interferon. There is good evidence that gene silencing and immunostimulation are two independent functional characteristics of RNA oligonucleotides. Immunorecognition of RNA depends on certain molecular features such as length, double- versus single-strand configuration, sequence motifs, and nucleoside modifications such as triphosphate residues. RNA-sensing immunoreceptors include three members of the Toll-like receptor (TLR) family (TLR3, TLR7, TLR8) and cytosolic RNA-binding proteins like PKR and the helicases RIG-I and Mda5. Detection of RNA molecules occurs during viral infection and triggers antiviral innate defense mechanisms including the induction of type I interferons (IFN-alpha, IFN-beta) and downregulation of gene expression. Type I interferon induction by synthetic siRNAs requires TLR7 and is sequence dependent, similar to the detection of CpG motifs in DNA by TLR9. Identification of the exact molecular mechanisms of immunorecognition of RNA will allow the development of methods to avoid immunostimulation of siRNA and the design of potent immunostimulatory RNA (isRNA) oligonucleotides, depending on the aim. Furthermore, the combination of both gene-silencing and immunostimulation in one RNA molecule may lead to novel drugs that use both functional activities of RNA as two edges of one sword for effective treatment of viral infection and cancer.     

Overt and imagined singing of an Italian aria

Activation maps of 16 professional classical singers were evaluated during overt singing and imagined singing of an Italian aria utilizing a sparse sampling functional magnetic imaging (fMRI) technique. Overt singing involved bilateral primary and secondary sensorimotor and auditory cortices but also areas associated with speech and language production. Activation magnitude within the gyri of Heschl (A1) was comparable in both hemispheres. Subcortical motor areas (cerebellum, thalamus, medulla and basal ganglia) were active too. Areas associated with emotional processing showed slight (anterior cingulate cortex, anterior insula) activation. Cerebral activation sites during imagined singing were centered on fronto-parietal areas and involved primary and secondary sensorimotor areas in both hemispheres. Areas processing emotions showed intense activation (ACC and bilateral insula, hippocampus and anterior temporal poles, bilateral amygdala). Imagery showed no significant activation in A1. Overt minus imagined singing revealed increased activation in cortical (bilateral primary motor; M1) and subcortical (right cerebellar hemisphere, medulla) motor as well as in sensory areas (primary somatosensory cortex, bilateral A1). Imagined minus overt singing showed enhanced activity in the medial Brodmann's area 6, the ventrolateral and medial prefrontal cortex (PFC), the anterior cingulate cortex and the inferior parietal lobe. Additionally, Wernicke's area and Brocca's area and their homologues were increasingly active during imagery. We conclude that imagined and overt singing involves partly different brain systems in professional singers with more prefrontal and limbic activation and a larger network of higher order associative functions during imagery.     

Comparison of the AVPU Scale and the Pediatric GCS in Prehospital Setting

Objective: The pediatric Glasgow coma scale (pGCS) is a consciousness score that, although widely applied, requires skill to apply. The AVPU scale uses four simple categories (Alert; Verbal response; response to Pain; Unresponsive), but has not been studied in a large pediatric population. We compared the performance of the AVPU and pGCS scales in a large pediatric cohort in an acute, prehospital setting. Methods: In a six-month-long prospective cohort study, AVPU and pGCS scores were determined by emergency physicians in children less than 10 years of age at their first prehospital encounter. Results: We included 302 children (median age 2.3 years) with a broad spectrum of diagnoses. Data were complete for 287 children. AVPU and pGCS scores showed good a correlation in the extreme categories A and U (positive predictive values of 98% and 100%, respectively). Corresponding pGCS scores for each AVPU category were as follows: 11–15 for A; 5–15 for V; 4–12 for P; and 3–5 for U. The positive predictive value to detect patients with pGCS ≥ 8 for AVPU category V was 100%. Conclusions: We demonstrated good correlation of simple and fast consciousness AVPU scoring to the standard pGCS in a large cohort of pediatric patients in a prehospital setting. The AVPU category “V” identifies patients with a pGCS of or exceeding 8 and, therefore, identifies children at low risk requiring more invasive procedures or intensive care treatment.     

Effects of inhaled nitric oxide on right ventricular function in severe acute respiratory distress syndrome

Objective To compare the effects of inhaled nitric oxide (NO) and an infusion of prostacyclin (PGI₂) on right ventricular function in patients with severe acute respiratory distress syndrome (ARDS).Design Randomized prospective short-term study.Setting: Post-surgical ICU in an university hospital.Patients 10 patients with severe ARDS referred to our hospital for intensive care.Interventions In random sequence the patients inhaled NO at a concentration of 18 parts per million (ppm) followed by 36 ppm, and received an intravenous infusion of PGI₂ (4 ng·kg^–1·min^–1).Measurement and results Inhalation of 18 ppm NO reduced the means (±SE) pulmonary artery pressure (PAP) from 33±2 to 28±1 mmHg (p=0.008), increased right ventricular ejection fraction (RVEF), as assessed by thermodilution technique, from 28±2 to 32±2% (p=0.005), decreased right ventricular end-diastolic volume index from 114±6 to 103±8 ml·m^–2 (p=0.005) and right ventricular end-systolic volume index from 82±4 to 70±5 ml·m^–2 (p=0.009). Mean arterial pressure (MAP) and cardiac index (CI) did not change significantly. The effects of 36 ppm NO were not different from the effects of 18 ppm NO. Infusion of PGI₂ reduced PAP from 34±2 to 30±2 mmHg (p=0.02), increased RVEF from 29±2 to 32±2% (p=0.02). Right ventricular end-diastolic and end-systolic volume indices did not change significantly. MAP decreased from 80±4 to 70±5 mmHg (p=0.03), and CI increased from 4.0±0.5 to 4.5±0.5 l·min^–1·m^–2 (p=0.02).Conclusions Using a new approach to selective pulmonary vasodilation by inhalation of NO, we demonstrate in this groups of ARDS patients that an increase in RVEF is not necessarily associated with a rise in CI. The increase in CI during PGI₂ infusion is probably related to the systemic effect of this substance.Supported by DFG Fa 139/1-2/2-2