Augmenting the effective field of view of optical tracking cameras--a way to overcome difficulties during intraoperative camera alignment

An Internet survey demonstrated the existence of problems related to intraoperative tracking camera set-up and alignment. It is hypothesized that these problems are a result of the limited field of view of today's optoelectronic camera systems, which is usually insufficiently large to keep the entire site of surgical action in view during an intervention. A method is proposed to augment a camera's field of view by actively controlling camera orientation, enabling it to track instruments as they are used intraoperatively. In an experimental study, an increase of almost 300% was found in the effective volume in which instruments could be tracked.

A global view of Staphylococcus aureus whole genome expression upon internalization in human epithelial cells

BACKGROUND: Staphylococcus aureus, a leading cause of chronic or acute infections, is traditionally considered an extracellular pathogen despite repeated reports of S. aureus internalization by a variety of non-myeloid cells in vitro. This property potentially contributes to bacterial persistence, protection from antibiotics and evasion of immune defenses. Mechanisms contributing to internalization have been partly elucidated, but bacterial processes triggered intracellularly are largely unknown. RESULTS: We have developed an in vitro model using human lung epithelial cells that shows intracellular bacterial persistence for up to 2 weeks. Using an original approach we successfully collected and amplified low amounts of bacterial RNA recovered from infected eukaryotic cells. Transcriptomic analysis using an oligoarray covering the whole S. aureus genome was performed at two post-internalization times and compared to gene expression of non-internalized bacteria. No signs of cellular death were observed after prolonged internalization of Staphylococcus aureus 6850 in epithelial cells. Following internalization, extensive alterations of bacterial gene expression were observed. Whereas major metabolic pathways including cell division, nutrient transport and regulatory processes were drastically down-regulated, numerous genes involved in iron scavenging and virulence were up-regulated. This initial adaptation was followed by a transcriptional increase in several metabolic functions. However, expression of several toxin genes known to affect host cell integrity appeared strictly limited. CONCLUSION: These molecular insights correlated with phenotypic observations and demonstrated that S. aureus modulates gene expression at early times post infection to promote survival. Staphylococcus aureus appears adapted to intracellular survival in non-phagocytic cells.

Aprotinin in cardiac surgery: a different point of view

Aprotinin is widely used in cardiac surgery to reduce postoperative bleeding and the need for blood transfusion. Controversy exists regarding the influence of aprotinin on renal function and its effect on the incidence of perioperative myocardial infarction (MI) and cerebrovascular incidents (CVI). In the present study, we analyzed the incidence of these adverse events in patients who underwent coronary artery bypass grafting (CABG) surgery under full-dose aprotinin and compared the data with those recently reported by Mangano et al [2006]. For 751 consecutive patients undergoing CABG surgery under full-dose aprotinin (>4 million kalikrein-inhibitor units) we analyzed in-hospital data on renal dysfunction or failure, MI (defined as creatine kinase-myocardial band > 60 iU/L), and CVI (defined as persistent or transient neurological symptoms and/or positive computed tomographic scan). Average age was 67.0 +/- 9.9 years, and patient pre- and perioperative characteristics were similar to those in the Society of Thoracic Surgeons database. The mortality (2.8%) and incidence of renal failure (5.2%) ranged within the reported results. The incidence rates of MI (8% versus 16%; P < .01) and CVI (2% versus 6%; P < .01) however, were significantly lower than those reported by Mangano et al. Thus the data of our single center experience do not confirm the recently reported negative effect of full-dose aprotinin on the incidence of MI and CVI. Therefore, aprotinin may still remain a valid option to reduce postoperative bleeding, especially because of the increased use of aggressive fibrinolytic therapy following percutaneous transluminal coronary angioplasty.

Discovery of novel CB2 receptor ligands by a pharmacophore-based virtual screening workflow

Cannabinoid receptor 2 (CB(2) receptor) ligands are potential candidates for the therapy of chronic pain, inflammatory disorders, atherosclerosis, and osteoporosis. We describe the development of pharmacophore models for CB(2) receptor ligands, as well as a pharmacophore-based virtual screening workflow, which resulted in 14 hits for experimental follow-up. Seven compounds were identified with K(i) values below 25 microM. The CB(2) receptor-selective pyridine tetrahydrocannabinol analogue 8 (K(i) = 1.78 microM) was identified as a CB(2) partial agonist. Acetamides 12 (K(i) = 1.35 microM) and 18 (K(i) = 2.1 microM) represent new scaffolds for CB(2) receptor-selective antagonists and inverse agonists, respectively. Overall, our pharmacophore-based workflow yielded three novel scaffolds for the chemical development of CB(2) receptor ligands.

[Cross-talk between heart and kidney--mechanisms and management of the cardiorenal syndrome from a nephrologists view]

Renal dysfunction represents a frequent comorbidity in patients with in chronic heart failure and is not only a strong predictor of mortality, but also causally linked to the development and progression of CHF. Mechanisms involved in the cross-talk between the kidney and the heart include the up-regulated sympathetic nerve system, activation of the renin-angiotensin-aldosterone system, vasopressin release and decreased activity of arterial baroreceptors and natriuretic peptides resulting in abnormal salt and water retention. The main therapeutic goals for patients with the so-called cardiorenal syndrome is the normalization of volume status while avoiding overdiuresis and renal dysfunction as well as the implementation of an evidence-based pharmacologic treatment to improve patient outcome. If these two goals are not achieved with conventional therapy, renal replacement therapy should be discussed in an interdisciplinary approach. All current renal replacement techniques have proved to be useful in controlling hypervolemia and ameliorating functional cardiac parameters and quality of life in patients with heart failure. Nevertheless, the influence of renal replacement therapy on long-term survival of affected patients has not been addressed in large controlled studies.