Theoretical surgery: a new specialty in operative medicine

Theoretical surgery is defined as a nonoperative decision analysis and clinical and basic research supporting system for surgery. It developed to meet the needs of academic surgeons to coordinate communication with basic science disciplines. This article summarizes the development of this idea at the University of Marburg where theoretical surgery has reached departmental and institutional proportions. Its objectives and methods are described. Central to its operation are permanent working teams of 2 clinical surgeons, 1 basic scientist (theoretical surgeon), 1-2 technicians, and 1-2 students focusing on one problem in a joint interdisciplinary manner. Decision analysis with classification methods and the creation of decision trees and algorithms are central to the operation of this experiment. Lessons learned from this academic experiment and the accomplishments during the past 20 years are summarized on 3 levels of efficacy: performance, changing strategies, and outcome

Quantifizierung des perioperativen Risikos [Quantifications of perioperative risk]

In this paper standardized and quantitative definitions of perioperative risk and risk factor using probabilities are given. A calculation of risk and risk factors is performed using data from a study on perioperative risk in colon resection and a study on a preoperative risk check in general surgery. The problem of one risk factor, a combination of two risk factors and the use of many risk factors to quantify preoperative risk is discussed. Confidence intervals are recommended as a standard method for presenting statistical results on perioperative risk

Histamine release after intravenous application of short-acting hypnotics. A comparison of etomidate, Althesin (CT1341) and propanidid

The subject of histamine release was investigated in 16 volunteers by means of plasma histamine determination after the administration of etornidate, Althesin, propanidid, and Cremophor EL. Althesin and propanidid caused release of histamine in various degrees of frequency. Blood pressure changes were rather pronounced with both anaesthetic agents; tachycardia reached its maximum in the first and second minute, which seems to be an argument against histamine release as the underlying cause of this reaction. Histamine was, indeed, only released to such an extent (with the exception of one borderline case) that no clinical symptoms other than secretion of gastric juice and erythema were to be expected. After the application of etomidate and Cremophor EL an increase in plasma histamine was not detectable. Changes in the differential blood picture in terms of a decrease in basophils only occurred after Althesin and propanidid; not, however, after etomidate and Cremophor EL. Etomidate is, therefore, the first hypnotic drug for intravenous application which is unlikely to cause chemical histamine release

Attacking Graph Neural Networks with Bit Flips: Weisfeiler and Lehman Go Indifferent

Prior attacks on graph neural networks have mostly focused on graph poisoning and evasion, neglecting the network's weights and biases. Traditional weight-based fault injection attacks, such as bit flip attacks used for convolutional neural networks, do not consider the unique properties of graph neural networks. We propose the Injectivity Bit Flip Attack, the first bit flip attack designed specifically for graph neural networks. Our attack targets the learnable neighborhood aggregation functions in quantized message passing neural networks, degrading their ability to distinguish graph structures and losing the expressivity of the Weisfeiler-Lehman test. Our findings suggest that exploiting mathematical properties specific to certain graph neural network architectures can significantly increase their vulnerability to bit flip attacks. Injectivity Bit Flip Attacks can degrade the maximal expressive Graph Isomorphism Networks trained on various graph property prediction datasets to random output by flipping only a small fraction of the network's bits, demonstrating its higher destructive power compared to a bit flip attack transferred from convolutional neural networks. Our attack is transparent and motivated by theoretical insights which are confirmed by extensive empirical results

Differential effects of antibiotics in combination with G-CSF on survival and polymorphonuclear granulocyte cell functions in septic rats

<p>Abstract</p> <p>Background</p> <p>In addition to their antimicrobial activity, antibiotics modulate cellular host defence. Granulocyte-colony stimulating factor (G-CSF) is also a well known immunomodulator; however little is known about the interactions of G-CSF with antibiotics. We investigated in septic rats the effects of two antibiotic combinations with G-CSF.</p> <p>Methods</p> <p>In two clinic modelling randomised trials (CMRTs), male Wistar rats were anesthetized, given antibiotic prophylaxis, had a laparotomy with peritoneal contamination and infection (PCI), and were randomly assigned (n = 18 rats/group) to: 1) PCI only; 2) PCI+antibiotic; and, 3) PCI+antibiotic+G-CSF prophylaxis (20 μg/kg, three times). This sequence was conducted first with 10 mg/kg coamoxiclav, and then with ceftriaxone/metronidazole (Cef/met, 10/3 mg/kg). In additional animals, the blood cell count, migration and superoxide production of PMNs, systemic TNF-α and liver cytokine mRNA expression levels were determined.</p> <p>Results</p> <p>Only the combination coamoxiclav plus G-CSF improved the survival rate (82 vs. 44%, p < 0.001). Improved survival with this combination was accompanied by normalised antimicrobial PMN migratory activity and superoxide production, along with normalised systemic TNF-α levels and a reduced expression of TNF-α and IL-1 in the liver.</p> <p>Conclusion</p> <p>There are substantial differences in the interaction of antibiotics with G-CSF. Therefore, the selection of the antibiotic for combination with G-CSF in sepsis treatment should be guided not only by the bacteria to be eliminated, but also by the effects on antimicrobial functions of PMNs and the cytokine response.</p