Update in perioperative medicine: practice changing evidence published in 2016.

This summary reviews 18 key articles published in 2016 which have significant practice implications for the perioperative medical care of surgical patients. Due to the multi-disciplinary nature of the practice of perioperative medicine, important new evidence is published in journals representing a variety of medical and surgical specialties. Keeping current with the evidence that drives best practice in perioperative medicine is therefore challenging. We set out to identify, critically review, and summarize key evidence which has the most potential for practice change. We integrated the new evidence into the existing body of medical knowledge and identified practical implications for real world patient care. The articles address issues related to anticoagulation, transfusion threshold, immunosuppressive medications, postoperative delirium, myocardial injury after noncardiac surgery, postoperative pain management, perioperative management of antihypertensives, perioperative fasting, and perioperative diabetic control.

Ten years of infliximab (remicade) in clinical practice: the story from bench to bedside.

Infliximab was first introduced in Europe in 1999 for Crohn's disease. During the following decade major progress was made in the understanding of the pathophysiology of inflammatory bowel diseases and treatment with infliximab. Today, treatment algorithms with anti-TNF and optimization of anti-TNF use in daily clinical practice are important research topics in Crohn's disease and ulcerative colitis. TNF blockade has also changed the rheumatology practice during the last 10 years. Earlier treatment, combination with disease modifying anti-rheumatic drugs, and identification of risk factors of poor prognosis are hot research topics today. The introduction of infliximab (among other biological therapies) has thus changed the way how inflammatory bowel diseases and rheumatoid conditions are treated. More importantly, infliximab has offered significant improvement of the quality of life of many patients. In addition, we currently collect data indicating that infliximab is changing the natural course of these inflammatory diseases.

Comparison of two enzyme immunometric assays to measure tumor necrosis factor-alpha in human serum.

BACKGROUND: Tumor necrosis factor-alpha is a 17.5 kDa, 157 amino acid protein that is a potent lymphoid factor, which exerts cytotoxic effects on a wide range of tumor cells and other target cells. TNF-alpha has been suggested to play a pro-inflammatory role by influencing transendothelial migration of monocytes and elicits the expression of proteolytic enzymes by macrophages and smooth muscle cells within the atherosclerotic plaque. METHODS: We compared two methods for the quantitative determination of human tumor necrosis factor-alpha in serum samples. Either kit follows the same assay procedure. Serum samples do not need to be diluted before sampling. Standard is provided lyophilized and serial dilutions after reconstitution generate the standard point curves. The tests are enzyme immunometric assays based on a standard 96-well microtiter plate. The wells are coated with anti-human TNF-alpha antibody. RESULTS: The range of the standard curve is similar in both kits. It spans from 1000 through 15.6 pg/mL. The median TNF-alpha concentration in samples measured by Pierce assay (n=368) was 4.23 pg/mL, (range, 1.34-77.2 pg/mL). A very different median was obtained for the same specimen measured with the Titerzyme EIA (median, 176.96 pg/mL; range, 54.7-283.9 pg/mL; n=364). Substantial significant differences were observed between the two methods. CONCLUSION: Our results show that the two kits are unmatchable for results they can give when TNF-alpha concentrations are measured in serum samples. One reason of this disagreement could be the matrix effect or a cross-reactivity of one of the two methods. This study shows that the determination of human serum TNF-alpha needs to be standardized, especially when a comparison of results is required.

Blood levels of nitric oxide, C-reactive protein, and tumor necrosis factor-alpha are upregulated in patients with malignancy-associated hypercoagulable state: pathophysiologic implications.

Endogenous generation of nitric oxide (NO) plays an important role in the regulation of cardiovascular and inflammatory responses. This mediator is synthesized by a family of enzymes collectively known as NO synthase. Several isoforms of this enzyme have been identified and can be grouped as constitutive or inducible. Increased production of NO is reported in several inflammatory disorders, such as sepsis, arthritis, thrombotic thrombocytopenic purpura (TTP), and antiphospholipid syndrome. In addition, NO upregulates cyclo-oxygenase-2 and synthesis of several other inflammatory cytokines. Inflammation and thrombotic complications are usually associated with malignancy. Earlier reports indicate the upregulation of tumor necrosis factor-alpha (TNF-alpha), C-reactive protein (CRP), and tissue factor (TF) in patients with malignancy. To determine the relationship between inflammatory cytokines and NO in cancer patients with hypercoagulable states, baseline plasma samples from 160 patients with confirmed malignancy and hypercoagulable state were analyzed for NO levels. A chemical method based on a chemiluminescent reaction between NO and ozone using a highly sensitive gas phase NO analyzer was used. CRP, TF, and TNF-alpha were measured using enzyme-linked immunosorbent assay methods. Of the 160 patients who were plasma tested, the baseline NO levels ranged from 13.7 to 98.6 microM (63.1+/-15.9 microM, mean+/-SD) in contrast to age-matched control, which ranged from 9.1 to 34.6 microM (19.8+/-6.2 microM, mean+/-SD, n=138). Cancer patients also showed marked variations in the NO levels. Eighteen of 60 cancer patients exhibited greater than 60 microM NO levels. The CRP, TNF-alpha and TF were also significantly elevated. A correlation between CRP (r(2)=0.73) and NO levels was noted in cancer patients with hypercoagulable state. These data suggest that the pathogenesis associated with malignancy/hypercoagulable state is associated with an inflammatory component. In addition, the observed hemodynamic changes in some of the cancer patients may be due to increased NO production.

Determination of human tumor necrosis factor alpha by a highly sensitive enzyme immunoassay.

Tumor necrosis factor alpha (TNF-alpha) is a polypeptide produced primarily by monocytes and macrophages. It is involved in a wide variety of immune reactions. A simple and sensitive microplate enzyme-linked immunosorbent assay for the detection of hTNF-alpha in serum, plasma, and cell culture supernatants is described. The method is based on the use of horseradish peroxidase in biotin-streptavidin amplification system which is performed in Nunc StarWell. This system has enabled us to achieve a sensitivity of 0.1 pg hTNF-alpha/ml of the sample. The assay is calibrated to the World Health Organization (WHO) standard for hTNF-alpha (87/650). The within-run coefficient of variation ranged from 3.7 to 5.9 and the between-run coefficient of variation ranged from 8.0 to 9.9. The results obtained by the proposed method and by a commercially available kit (DRG hTNF-alpha ELISA) correlated well (n = 20, r = 0.956).

Measurement by quantitative reverse transcription-polymerase chain reaction of the levels of tumor necrosis factor alpha mRNA in atherosclerotic arteries in Watanabe heritable hyperlipidemic rabbits.

Tumor necrosis factor-alpha (TNF-alpha), produced by activated monocytes and other cells, has been proposed as a mediator of importance in atherosclerosis. In this study, we use a newly developed technique, quantitative reverse transcription-polymerase chain reaction (RT-PCR), to measure the mRNA levels of TNF-alpha in arteries of Watanabe Heritable Hyperlipidemic (WHHL) rabbits in relation to the progression of atherosclerosis. Co-amplification of known amounts of TNF-alpha RNA and TNF-alpha internal control RNA indicated that the quantitative RT-PCR method was quite reliable, with a < 5% difference between TNF-alpha mRNA levels deduced from the standard curve and actually loaded TNF-alpha mRNA. As another control, TNF-alpha mRNA levels in lipopolysaccharide-induced (LPS-induced) and uninduced monocytes were measured, and a 9.3-fold increase in the TNF-alpha mRNA levels was observed in LPS-induced monocytes. TNF-alpha mRNA levels in the aortic arches of healthy New Zealand White (NZW) rabbits was 0.0112 -/+ 0.0016 (SD) pg per ng tissue RNA. TNF-alpha mRNA levels in the aortic arches and descending thoracic aortas of 6-month-old WHHL rabbits were 0.0273 -/+ 0.0066 pg and 0.0176 -/+ 0.0013 pg per ng tissue RNA, respectively. TNF-alpha mRNA levels in the aortic arches and descending thoracic aortas of 18-month-old WHHL rabbits were much higher than in those of 6-month-old WHHL rabbits, with values of 0.2107 -/+ 0.0205 pg and 0.1043 -/+ 0.0196 pg per ng tissue RNA, respectively. These findings indicate that: a) Quantitative RT-PCR can be used to measure levels of small abundance RNA in normal and diseased tissues accurately; b) no significant increase in TNF-alpha mRNA levels was observed in the aortic arches and descending thoracic aortas of 6-month-old WHHL rabbits compared with those of NZW rabbits, although they had multiple raised intimal lesions; and c) a significantly elevated total tissue level of TNF-alpha mRNA is demonstrable late in the course of atherosclerosis in 18-month-old WHHL rabbits (Bonferroni method). These findings suggest that TNF-alpha might play an important role in the progression of advanced atherosclerosis, although total tissue levels of TNF-alpha mRNA are not unequivocally elevated earlier in the course of the disease.

International collaborative study of the candidate international standards for human tumour necrosis factors alpha (hTNF-alpha) and beta (hTNF-beta) and for murine tumour necrosis factor alpha (mTNF-alpha).

Four ampouled preparations of human tumour necrosis factor alpha (hTNF-alpha), one ampoule of human tumour necrosis factor beta (hTNF-beta) and one ampoule of mouse tumour necrosis factor alpha (mTNF-alpha) were evaluated by 20 laboratories in nine countries for their suitability to serve as international standards for these materials. A further three preparations of recombinant hTNF-alpha were included in the study so that hTNF-alpha preparations from different sources and with various structures could be compared. The preparations were assayed using in vitro bioassays and immunoassays. On the basis of the results reported here, with the agreement of participants in the study and with the authorisation of the Expert Committee on Biological Standardization (ECBS) of the World Health Organization (WHO), the preparation of hTNF-alpha in ampoules designated 87/650 was established as the international standard for hTNF-alpha with a defined potency of 40,000 international units per ampoule. Estimates relative to hTNF-alpha for both hTNF-beta and mTNF-alpha showed a substantial inter-laboratory variability in cytotoxic activity indicating that no preparations of hTNF-alpha would be suitable as a reference standard for either hTNF-beta or mTNF-alpha. However, given the current need for reference preparations for these materials, the ampouled preparations of hTNF-beta (87/640) and mTNF-alpha (88/532) were assigned potencies in arbitrary units and are available as reference reagents.

Measurement of immunoreactive interleukin-1 beta from human mononuclear cells: optimization of recovery, intrasubject consistency, and comparison with interleukin-1 alpha and tumor necrosis factor.

Numerous studies have reported altered levels of in vitro production of the cytokines interleukin-1 (IL-1) and tumor necrosis factor (TNF) from blood leukocytes in various human disease states. Most of these studies have used bioassays which are vulnerable to inhibitors produced by these cells. Furthermore in vitro cytokine production is often assessed on a single occasion. The present study was designed to standardize stimulation conditions for in vitro IL-1 beta production and to employ a competitive radioimmunoassay (RIA) to demonstrate reproducibility and long-term variation of in vitro cytokine production in a cohort of healthy human subjects. We also examined relative amounts of immunoreactive IL-1 beta, IL-1 alpha, and TNF induced by the stimuli endotoxin, phytohemagglutinin, or Staphylococcus epidermidis. We show that the RIA can reliably detect IL-1 beta produced from mononuclear cells in concentrations as low as 115 pg/ml. Lysing cells by repeated freeze-thawing yields maximal recovery of total (i.e., secreted plus cell-associated) immunoreactive IL-1 beta, when compared to extraction with the detergent CHAPS or addition of protease inhibitors. Repeated measurement of in vitro cytokine production on different days within 1 week shows good reproducibility for a given individual and a given stimulus (variation coefficient 20 to 30%). Over a long time period (6 months) in vitro cytokine production is stable in some individuals but changes considerably in others. The soluble stimulus endotoxin induces twofold more IL-1 alpha than IL-1 beta or TNF; in contrast the phagocytic stimulus heat-killed S. epidermidis induces fourfold more IL-1 beta and TNF than IL-1 alpha. This distinct pattern of cytokine response indicates differential stimulation of the mononuclear cells by different stimuli. The results form the basis for studying in vitro cytokine production in different human disease states.

Parameters for the evaluation of long-term stability of tumour necrosis factor preparations.

Escherichia coli-derived Tumour Necrosis Factor (TNF) was formulated in the absence of a protein-carrier, both as a solution and as a lyophilized preparation. By means of three stability-indicating test methods (bioassay, SDS-PAGE, IEF), the long-term stability of these TNF preparations was evaluated. Both preparations showed no change upon storage for 9 months at -70 degrees C and -20 degrees C. Depending upon the test method, different rates of change were detected at elevated temperature. The analysis presented will assist in the design of future TNF reference standards.