Protein sparing during general anesthesia with a propofol solution containing medium-chain triglycerides for gastrectomy: comparison with sevoflurane anesthesia

Purpose

Despite the importance of the inhibition of catabolic response to surgery, the effects of different anesthetic techniques on the catabolic response in surgical patients are controversial. This study compared the endocrine-metabolic responses and protein catabolism during gastrectomy in patients who received either sevoflurane or propofol anesthesia with remifentanil.

Methods

Thirty-seven patients (American Society of Anesthesiologists status I–III) aged 20–79 years undergoing elective gastrectomy were randomly assigned to receive sevoflurane anesthesia with remifentanil (n = 19) or intravenous propofol anesthesia (Propofol-Lipuro^® 1 %; B. Braun, Melshungen AG, Germany) with remifentanil (n = 18). Urine samples were collected every 1 h after skin incision (0 h) and the urinary 3-methylhistidine:creatinine ratio (3-MH/Cr ratio) was used as a marker of protein catabolism. Respiratory quotient was measured during a 1 h period following skin incision.

Results

The 3-MH/Cr ratio significantly increased at 1–2 and 2–3 h compared to 0 and 0–1 h in both groups, but the propofol group exhibited a lower 3-MH/Cr ratio (nmol/μmol) than the sevoflurane group at 1–2 h (15.7 vs. 18.2, P = 0.012) and 2–3 h (15.9 vs. 18.1, P = 0.025). A difference was observed in the respiratory quotient between the sevoflurane and propofol groups (0.726 vs. 0.707, P = 0.003).

Conclusion

A lower 3-MH/Cr ratio and a lower respiratory quotient during propofol anesthesia, compared to those exhibited during sevoflurane anesthesia, suggest that protein sparing probably occurs through the utilization of medium-chain triglycerides contained in the fat emulsion of propofol solution as a fuel source.     

Arachidonic acid preserves hippocampal neuron membrane fluidity in senescent rats

Previous studies indicate that long-term dietary supplementation with arachidonic acid (AA) in 20-month-old rats (OA) effectively restores performance in a memory task and the induction of long-term potentiation in the hippocampus to the level of young control animals (YC). The present study examined protein mobility using the live cell imaging technique "Fluorescent Recovery After Photobleaching (FRAP)" in YC, old control (OC) and OA neurons in hippocampal slice preparations. Three measures; mobile fraction (M(f)), diffusion constant (D) and time constant (tau), were estimated among YC, OC and OA. Each of these parameters was significantly different between OC and YC, suggesting that membrane fluidity is lower in OC than in YC. In contrast, D and tau were comparable in OA and YC, indicating that hippocampal neuronal membranes supplemented with AA were more fluid than those in OC, whereas the fraction of diffusible protein in the bleached region remained smaller than in YC. Long-term administration of AA to senescent rats might help to preserve membrane fluidity and maintain hippocampal plasticity.     

Cytochemical analysis of storage materials in cultured skin fibroblasts from patients with I-cell disease

BACKGROUND: In cultured fibroblasts from I-cell disease patients the transport of many lysosomal enzymes is defective, and affected cells contain inclusion bodies filled with undegraded substrates. However, the contents of these inclusion bodies have not been well characterized yet. We attempted to identify accumulated substances in cultured I-cell disease fibroblasts cytochemically. METHODS: Cultured fibroblasts from I-cell disease patients were double-stained with a monoclonal antibody to lysosome-associated membrane protein-1 (LAMP-1) and that to GM2 ganglioside, or a series of lectins that specifically bind to sugar moieties. RESULTS: The patients' cells were granularly stained with the antibody to GM2 ganglioside and the lectins including Maakia amurensis, Datura stramonium, and concanavalin A. Their localization was coincident with that of LAMP-1. CONCLUSIONS: GM2 ganglioside and various kinds of glycoconjugates having sialic acidalpha2-3galactose, galactosebeta1-4N-acetylglucosamine and mannose residues accumulate in enlarged lysosomes in I-cell disease fibroblasts.     

Tissue Characterization of Progressive Cardiac Allograft Vasculopathy in Patients With Everolimus Therapy Compared With Donor-Transmitted Atherosclerosis Assessed Using Serial Intravascular Imaging: A Case Report

Using serial intravascular ultrasound (IVUS), integrated-backscatter IVUS, and optical coherence tomography, we observed rapidly progressive cardiac allograft vasculopathy (CAV) and donor-transmitted plaque in the left anterior descending artery. Late-phase everolimus-resistant CAV had a rapidly progressive course (maximal intimal thickness [MIT] increased by 0.5 mm between years 3 and 4 after cardiac transplantation, from MIT growth <0.5 mm at year 1). Conversely, the donor-transmitted plaque grew slowly (0.1 mm increase during the same period). Tissue characteristics in the 2 segments were also different; CAV had eccentric, noncalcified, and lipid-rich components and was associated with macrophage accumulation, whereas donor-transmitted atherosclerosis presented with typical features of atherosclerosis (ie, fibrocalcific plaque). CAV with late-phase progression involves everolimus resistance and features of vulnerable plaques seen in nontransplantation patients and is independent of donor-transmitted atherosclerosis.     

Reduced inspiratory flow attenuates IL-8 release and MAPK activation of lung overstretch.

Lung overstretch involves mechanical factors, including large tidal volumes (VT), which induce inflammatory responses. The current authors hypothesised that inspiratory flow contributes to ventilator-induced inflammation. Buffer-perfused rabbit lungs were ventilated for 2 h with 21%, O2+5%, CO2, positive end-expiratory pressure of 2-3 cmH2O and randomly assigned to either: 1) normal VT (6 mL x kg(-1)) at respiratory rate (RR) 30, inspiration:expiration time ratio (I:E) 1:1, low inspiratory flow 6 mL x kg(-1) x s(-1); 2) large VT (12 mL x kg(-1)) at RR 30, I:E 1:1, high inspiratory flow 12 mL x kg(-1) x s(-1) (HRHF); 3) large VT at RR 15, I:E 1:1, low inspiratory flow 6 mL x kg(-1) x s(-1) (LRLF); or 4) large VT at RR 15, I:E 1:2.3, high inspiratory flow 10 mL x kg(-1) x s(-1) (LRHF). Physiological parameters, tumour necrosis factor (TNF)-alpha, interleukin (IL)-8 and activation of mitogen-activated protein kinases (extracellular signal-regulated kinase (ERK)1/2, p38 and stress-activated protein kinase (SAPK)/ c-Jun N-terminal kinase (JNK)) were measured. HRHF increased weight gain, perfusate IL-8 and phosphorylation of ERK1/2, p38 and SAPK/JNK. These responses were absent during LRLF but present during LRHF. Changes in TNF-alpha were small. Tissue IL-8 and phospho-ERK1/2 staining was localised primarily to smooth muscle, adventitia and bronchial epithelium within larger bronchioles and arterioles. These results indicate that mild overstretch of perfused lungs during high inspiratory flow enhances inflammatory signalling by cells in lung regions most affected by strong turbulent airflow.     

Comparison of Insertion of the Modified i-gel Airway for Oral Surgery With the LMA Flexible: A Manikin Study

We previously modified the i-gel airway to enable its use in the field of oral and maxillofacial surgery and reported its fabrication methods. In general, the standard i-gel airway is quick to insert and has a high success rate, but the modified i-gel airway has yet to be assessed for these attributes. We, therefore, set out to compare the ease of insertion of the modified i-gel airway with the LMA Flexible to investigate the usefulness of the modified i-gel airway. The study participants, who included 20 new interns with no experience using either the LMA Flexible or the modified i-gel airway, inserted each device 3 times into an intubation practice manikin. The variables measured in this study were insertion time and rate of successful insertions. Mean insertion time over 3 attempts was significantly shorter for the modified i-gel™ airway (18.9 ± 4.7 seconds) than the LMA Flexible (24.9 ± 5.1 seconds, P < .001). The rate of successful insertions as a total of all 3 attempts was significantly higher for the modified i-gel airway (56/60 times, 93.3%) than the LMA Flexible (45/60 times, 75%; P = .012). When used by an inexperienced operator, the modified i-gel™ airway is faster and has a higher success rate than the LMA Flexible, suggesting that it can be easily manipulated during insertion.Key Words: Oral and maxillofacial surgery, Supraglottic airway device, Modified i-gel™ airwayThe first laryngeal mask (LMA) was the LMA Classic, developed by Dr Brain. It was later followed by a number of groundbreaking new products, such as the LMA ProSeal, which features a high-pressure seal and a gastric tube orifice, and the LMA Fastrack that can be used to pass an endotracheal tube into the trachea. Today, these and other products comprise the LMA family. One of them, the LMA Flexible (Laryngeal Mask Company, Jersey, UK; Figure 1: top) was developed for oral and maxillofacial surgery and other types of head and neck surgery. The flexible wire-reinforced airway tube of this device has the advantages of avoidance of interference with the operative field, even in oral surgery, and being able to withstand pressure from surgical manipulation.^1,2 Thus, the LMA Flexible is currently the gold standard supraglottic device in the field of oral and maxillofacial surgery. The flexibility of the shaft of the reinforced airway tube, however, makes it difficult to exert any force on the shaft,^1,2 making insertion more difficult than with the LMA Classic.³Open in a separate windowFigure 1.LMA Flexible (top) and modified i-gel airway (bottom).The i-gel airway (Intersurgical Ltd, Wokingham, UK) is a disposable supraglottic device that was developed by Dr Nasir. It consists of an airway tube with a noninflatable gel-like cuff designed to fit perfectly over the larynx and also has a gastric tube orifice. The i-gel airway features a high-pressure seal (pharyngeal leak pressure),⁴ potentially preventing leakage of blood and water into the airway, which is a frequent problem during dental treatment and in oral and maxillofacial surgery. Hence, although this device may be very useful in oral and maxillofacial surgery, its use is limited by the thickness of the shaft of the airway.We previously modified the i-gel airway (modified i-gel airway; Figure 1: bottom) to enable its use in the field of oral and maxillofacial surgery and reported its fabrication methods.⁵ In general, the standard i-gel airway is quick to insert and has a high success rate, but the modified i-gel airway has yet to be assessed for these attributes. We, therefore, set out to compare the ease of insertion of the modified i-gel airway and the LMA Flexible to investigate the usefulness of the modified i-gel airway.     

Thrombus-related focal in-stent restenosis after everolimus-eluting stent implantation

A 60-year-old man who had received repeated angioplasty for silent ischemia was suspected to have restenosis based on radioisotope imaging (exercise-RI) findings 6 months after everolimus-eluting stent (EES) implantation (3.5 × 28, 3.5 × 28, 3.0 × 18 mm). The stents had been implanted for chronic total occlusion of the right coronary artery (RCA), and the patient was on continuous dual antiplatelet therapy. Diagnostic angiography demonstrated in-stent restenosis in the proximal RCA, which was treated by optical coherence tomography (OCT)-guided cutting balloon angioplasty with distal protection. OCT findings of the stenotic segment before angioplasty showed that the lesion had complex features. The lesion was successfully dilated, and whitish material obtained by a distal protection device was composed of fibrin thrombi with neutrophils and small pieces of mature fibrocellular neointima. The mechanisms and patterns of restenosis after EES placement have not been well clarified. This case may reflect a restenosis pattern (i.e., asymptomatic, focal, and thrombi-related) in the era of the newer generation of drug-eluting stents.