Risk Factor Targeted Perioperative Care Reduces Anastomotic Leakage after Colorectal Surgery: The DoubleCheck study.

OBJECTIVE: The DoubleCheck study aimed to introduce pre- and perioperative interventions minimizing exposure to modifiable risk factors and determine its effect on CAL. SUMMARY BACKGROUND DATA: Colorectal anastomotic leakage (CAL) is a severe complication. In order to predict and prevent its occurrence, the LekCheck study identified intraoperative modifiable risk factors for CAL: anemia, hyperglycemia, hypothermia, incorrect timing of antibiotic prophylaxis, administration of vasopressors and epidural analgesia. METHODS: This international open-labelled interventional study was performed between September 2021 and December 2023. An enhanced care bundle consisting of anemia correction, glucose measurement, attaining normothermia, antibiotics administration within 60 to 15 minutes preoperatively, refraining from vasopressors and epidural analgesia was introduced. Primary outcome was the occurrence of intraoperative risk factors just prior to the anastomosis creation. Secondary outcomes were CAL and mortality. Univariate and multivariate regression analysis were performed to establish the relationship between the enhanced care bundle, exposure to the six factors and CAL. RESULTS: The historical LekCheck group consisted of 1572 patients versus 902 in the DoubleCheck. The LekCheck group had a mean of 1.84 risk factors versus 1.63 in DoubleCheck ( P <0.001). In the DoubleCheck significantly less patients had ≥3 risk factors ( P <0.001). CAL was significantly lower in the DoubleCheck group (8.6% vs. 6.2%, P =0.039). The reduction of CAL was associated with the enhanced care bundle in multivariate regression analysis (OR 1.521, 95% CI 1.01-2.29, P =0.045). The mortality rate did not differ significantly (1.3%, vs. 0.8%, P =0.237). CONCLUSIONS: The DoubleCheck study showed that optimization of modifiable risk factors reduced CAL in colorectal surgery.

Efficient numerical modeling of traffic noise.

An optimized method is presented for the numerical evaluation of the sound field generated by an incoherent line source, which is commonly used to model road and rail traffic noise. Two different solutions for the numerical integration over the line source are distinguished, a point source solution and a line source solution. With proper segmentation of the line source, both solutions yield accurate results. Special attention is paid to receiver positions close to the (infinite) line through the (finite) line source. At these positions, conventional methods give numerical errors, which occur frequently in calculations of large-scale noise maps of cities, employing automatically generated geographical input data. The problems are avoided by using the optimized method presented here. The method is based on a combination of angular segmentation and linear segmentation of the line source and can be used to minimize the number of point-to-point calculations for noise mapping.

Decreased peritoneal tissue plasminogen activator during prolonged laparoscopic surgery.

BACKGROUND: Peritoneal fibrinolysis is crucial in the peritoneal healing processes and subsequent adhesion formation. During conventional surgery, the peritoneal fibrinolytic system is rapidly disturbed. Short-term laparoscopy does not seem to affect peritoneal fibrinolysis. The aim of the present study was to assess the effect of prolonged laparoscopic surgery on peritoneal fibrinolysis. METHODS: Twelve consecutive patients undergoing laparoscopic gastric bypass surgery for morbid obesity were included in the study. During the procedure, biopsies of the parietal peritoneum were taken at the start of the procedure and each 45 min afterward. Tissue samples were homogenized and tissue-type plasminogen activator (tPA) antigen, tPA activity, urokinase-type PA antigen, and plasminogen activating inhibitors type 1 antigen were measured using commercial assay techniques. RESULTS: Both tPA antigen and its activity progressively decreased during the procedure, reaching significant levels after 90 min of surgery. The levels of uPA antigen and plasminogen activating inhibitors antigen did not significantly change throughout the procedure. CONCLUSIONS: As for conventional surgery, prolonged laparoscopic surgery causes a decreased fibrinolytic activity in the peritoneum due to decreased tPA levels.

Engineering modeling of traffic noise in shielded areas in cities.

A computational study of road traffic noise in cities is presented. Based on numerical boundary-element calculations of canyon-to-canyon propagation, an efficient engineering algorithm is developed to calculate the effect of multiple reflections in street canyons. The algorithm is supported by a room-acoustical analysis of the reverberant sound fields in the source and receiver canyons. Using the algorithm, a simple model for traffic noise in cities is developed. Noise maps and exposure distributions of the city of Amsterdam are calculated with the model, and for comparison also with an engineering model that is currently used for traffic noise impact assessments in cities. Considerable differences between the two model predictions are found for shielded buildings with day-evening-night levels of 40-60 dB at the facades. Further, an analysis is presented of level differences between the most and the least exposed facades of buildings. Large level differences are found for buildings directly exposed to traffic noise from nearby roads. It is shown that by a redistribution of traffic flow around these buildings, one can achieve low sound levels at quiet sides and a corresponding reduction in the percentage of highly annoyed inhabitants from typically 23% to 18%.

Peritoneal transforming growth factor beta-1 expression during laparoscopic surgery: a clinical trial.

BACKGROUND: Transforming growth factor-beta 1 (TGF-beta1) is a growth factor involved in various biologic processes, including peritoneal wound healing and dissemination of malignancies. Laparoscopic surgery is evolving rapidly, and indications are increasing. The peritoneal TGF-beta1 expression during laparoscopic surgery is unknown. METHODS: For this study, 50 patients scheduled for laparoscopic cholecystectomy were randomized into five groups, then surgically treated with various pressures, light intensities, and dissection devices. Peritoneal biopsies were taken at the beginning and end of surgery. Tissue concentrations of total and active TGF-beta1 were measured using enzyme-linked immunosorbent assay (ELISA) techniques. RESULTS: There was no significant difference in either total or active TGF-beta1 concentration between peritoneal biopsies taken at the start of surgery and samples taken at the end of the procedure. Patients who underwent surgery with the ultrasonic scalpel had significant lower levels of both active (p < 0.005) and total (p < 0.01) TGF-beta1 at the end of surgery than patients treated with electrocautery. Patients who had surgery with a high light intensity had significantly lower levels of total TGF-beta1 levels (p < 0.005) with an unchanged active part than patients who had surgery with low light intensity. CONCLUSION: The choice of dissection device and the light intensity used in laparoscopic surgery affect peritoneal TGF-beta1 concentrations, indicating that peritoneal biology can be affected by laparoscopic surgery. Because TGF-beta1 is involved in various biologic processes in the peritoneal cavity, this observation may have important clinical consequences.

Simulation of Sound Waves Using the Lattice Boltzmann Method for Fluid Flow: Benchmark Cases for Outdoor Sound Propagation.

Propagation of sound waves in air can be considered as a special case of fluid dynamics. Consequently, the lattice Boltzmann method (LBM) for fluid flow can be used for simulating sound propagation. In this article application of the LBM to sound propagation is illustrated for various cases: free-field propagation, propagation over porous and non-porous ground, propagation over a noise barrier, and propagation in an atmosphere with wind. LBM results are compared with solutions of the equations of acoustics. It is found that the LBM works well for sound waves, but dissipation of sound waves with the LBM is generally much larger than real dissipation of sound waves in air. To circumvent this problem it is proposed here to use the LBM for assessing the excess sound level, i.e. the difference between the sound level and the free-field sound level. The effect of dissipation on the excess sound level is much smaller than the effect on the sound level, so the LBM can be used to estimate the excess sound level for a non-dissipative atmosphere, which is a useful quantity in atmospheric acoustics. To reduce dissipation in an LBM simulation two approaches are considered: i) reduction of the kinematic viscosity and ii) reduction of the lattice spacing.

Interaction of domoic acid and several derivatives with kainic acid and AMPA binding sites in rat brain.

We have determined the inhibitory potencies of domoic acid and a series of derivatives of domoic acid at kainic acid and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) binding sites in rat forebrain membranes. These derivatives of domoic acid differed in the configuration, stereochemistry, and degree of saturation of the side chain attached to C-4 of the prolyl ring. The binding data were analyzed in terms of one or two classes of sites as appropriate. Domoic acid and kainic acid displayed similar inhibition constants at [3H]kainic acid sites (IC50 = 5 and 7 nM, respectively). At both kainic acid and AMPA binding sites, all of the compounds tested were less potent than domoic acid itself. At high affinity [3H]kainic acid sites, the derivatives could be categorized into two groups; those with nanomolar affinity and those with micromolar affinity. All members of the former group possessed a side chain with the first double bond intact and in the Z (cis) configuration. The more distal atoms present in the extended side chain of domoic acid did not appear to contribute to the high affinity interaction with the kainic acid receptor. Although all the compounds tested were weaker inhibitors of [3H]AMPA binding compared to [3H]kainic acid binding, there was a high correlation between the rank order of potency of the seven domoic acid derivatives at [3H]kainic acid and at [3H]AMPA binding sites. The inhibition data for kainic acid at [3H]AMPA binding sites were described adequately in terms of a 1-site model, whereas the data for domoic acid required two classes of sites.(ABSTRACT TRUNCATED AT 250 WORDS)

On-line variable live-adjusted displays with internal and external risk-adjusted mortalities. A valuable method for benchmarking and early detection of unfavourable trends in cardiac surgery.

OBJECTIVE: Benchmarking and early detection of unfavourable trends. METHODS: We implemented a dedicated project-orientated data warehouse, which continuously supplies data for on-line computing of the variable live-adjusted displays (VLADs). To calculate the expected cumulative mortality, we used the multi-variate logistic regression model of the EuroSCORE model. In addition to the external EuroSCORE standard, we calculated a centre-specific risk score for internal standards by analysing the data of 9135 patients, which enables both internal and external comparisons. The VLADs are embedded into the multi-purpose web-based information portal, so that the physicians can investigate several types of VLADs interactively: performance of different types of surgery and individual surgeons for different time intervals. We investigated clinically important events such as modification of operative techniques and personnel changes of the team by the VLADs. RESULTS: We found transient declines in the performance curves during major changes in patient management, indicating that systemic--rather than accidental or patient related factors--were involved in the mortality risk. The internal standard line represents these clusters more clearly than the external line. We evaluated examples of how periods of increased risk could be monitored by the VLAD curves: (1) the introduction of OPCAB surgery; (2) training of surgeons; (3) staff changes and staff-related management. CONCLUSIONS: On-line VLADs based on a day-to-day updated database, displaying both internal and external standards, are a helpful visualisation tool for earlier detection of unfavourable trends. They enable the surgeon teams and clinical management to take countermeasures at an early stage.

Use of carbon-13 in biosynthetic studies: origin of the malonyl coenzyme A incorporated into tetracycline by Streptomyces aureofaciens.

The proton noise decoupled 13C nuclear magnetic resonance spectrum of tetracycline hydrochloride prepared from Streptomyces aureofaciens cultures supplemented with [1-13C]acetate and [2-13C]acetate showed enrichment of nine alternating ring carbons. In addition, a small enrichment of the carboxamide carbon by [1-13C]acetate was observed. The labelling patterns clearly demonstrated the polyketide origin of the tetracyclic nucleus. The 13C nuclear magnetic resonance spectrum of tetracycline hydrochloride derived from [1,2-13C]acetate showed all 18 ring carbons as doublets with coupling constants appropriate for the incorporation of nine intact two-carbon precursors, confirming that head-to-tail condensation of C2 units had occurred. Absence of bond scission within the C2 units and a low level of uncoupled 13C in the carboxamide substituent indicated that when the organism is supplemented with acetate, malonyl coenzyme A used for tetracycline biosynthesis is formed by direct carboxylation of acetyl coenzyme A.

Biosynthesis of bikaverin in Fusarium oxysporum. Use of 13C nuclear magnetic resonance with homonuclear 13C decoupling to locate adjacent 13C labels.

Bikaverin obtained by supplementing cultures of Fusarium oxysporum with singly and doubly 13C labeled acetate was enriched by approximately 0.5 atom percent with the 13C isotope. At this low enrichment 13C NMR spectra of samples labeled from (1-13C)- and (2-13C) acetate did not show, unequivocally, the pattern of isotopic incorporation. Small sample size, poor solubility and difficulties in the assignment of resonances also restricted the amount of information thacetate. The difficulty was overcome by using 13C homonuclear single-frequency decoupling in conjunction with 1H heteronuclear decoupling to locate bonded 13C-13C pairs. The carbon skeleton of bikaverin was shown to be biosynthesized entirely by condensation of acetate units and the pattern of assembly was established.

Proof for the biosynthetic conversion of L-[indole-15N]tryptophan to [10-15N]anthramycin using (13C, 15N) labelling in conjunction with 13C-NMR and mass spectral analysis.

Using 13C-NMR and mass spectral analysis we have demonstrated that the N-10 nitrogen of anthramycin is biosynthetically derived from the indole-nitrogen of tryptophan. Our experimental approach was to bring a 15N atom, which is derived from L-[indole-15N]tryptophan, and a 13C atom which is derived from DL-[1-13C]tyrosine, into adjacent positions of anthramycin. From resonance intensities and 13C-15N spin-spin coupling in the 13C-NMR spectrum of didehydroanhydroanthramycin, a derivative of anthramycin, we could then determine the 13C enrichment at C-11 and the proportion of 13C bonded to 15N at N-10. These results when combined with mass spectral analysis and isotopic dilution measurements proved that the indole nitrogen of tryptophan was completely retained at N-10 of anthramycin.

Biosynthesis of hydrocarbons by algae: Decarboxylation of stearic acid to N-heptadecane inAnacystis nidulans determined by(13)C- and(2)H-labeling and(13)C nuclear magnetic resonance.

The distribution of isotopic labels inn-heptadecane enriched from [1,2-(13)C] and [2-(13)C, 2-(2)H3) acetates byAnacystis nidulans has been determined by(13)C nuclear magnetic resonance ((13)C NMR). Labeling with [1,2-(13)C] acetate is consistent with assembly from(13)C-(13)C units derived from an acetate "starter" group and 8 malonate units, as in fatty acid biosynthesis, followed by production of a methyl group through bond cleavage of the terminal(13)C-(13)C unit. A comparison of the hydrocarbon with palmitic acid (the only fatty acid produced in sufficient amount for NMR analysis) enriched from [2-(13)C,2-(2)H3]acetate by the same culture shows that they have retained the same fraction of(2)H at corresponding sites, and have therefore undergone identical biosynthetic and hydrogen-deuterium exchange processes, as would be expected ifn-heptadecane originates from de novo-synthesized stearic acid.

Sulfoquinovosyl diacylglycerols from the alga Heterosigma carterae.

An extract of the chloromonad Heterosigma carterae (Raphidophyceae), cultivated in natural seawater, contained a complex mixture of sulfoquinovosyl diacylglycerols. Palmitoyl (16:0), three isomers of hexadecenoyl (16:1 cis delta 9, delta 11, delta 13), and eicosapentenoyl (20:5) were found to be the main fatty acyl substituents. Exact double-bond sites were determined by mass spectrometry analysis of the corresponding nicotinyl derivatives. Four major sulfoquinovosyl diacylglycerol components were partially purified and identified as 1-4 by interpretation of their nuclear magnetic resonance and mass spectral data. In addition, complete analysis of the H. carterae sulfoquinovosyl diacylglycerols was performed using high-performance liquid chromatography combined with electrospray tandem mass spectrometry.

Factors associated with toilet training in the 1990s.

CONTEXT: Few studies have systematically evaluated the factors influencing toilet training in children with normal development. OBJECTIVES: To determine those child, parent, and environmental factors associated with toilet training completion, focusing on the influence of the child's temperament and development. DESIGN AND SETTING: Cross-sectional descriptive study of normal children, ages 15-42 months, attending 1 of 4 pediatric clinics in Milwaukee in 1995 and 1996. METHODS: Demographics for child, parents, and household were surveyed. Temperament was assessed using the Toddler Temperament Scale and the Behavioral Style Questionnaire. Child development was measured using the Bayley Scales of Infant Development II. MAIN OUTCOME MEASURE: Toilet training status was by parental report and was categorized as not trained, not currently training, in training, or training complete. RESULTS: The study population included 496 children, comprising 219 that had not started training, 70 that were not currently training, 148 that were in training, and 59 that were completely trained. The ages at which 50% of the children were predicted to be toilet trained were 35 and 39 months for girls and boys, respectively. In the multivariate regression model, statistically significant factors best predicting toilet training completion were older age, non-Caucasian race, female gender, and single parenthood. Temperament, development, maternal employment, or use of day care were not statistically significant factors. CONCLUSION: Innate factors such as older age, non-Caucasian race, and female gender are the best predictors of completing toilet training (rather than a child's temperament and developmental stage). Day care and maternal employment appear to be unimportant variables. Parents should not be discouraged, because children are completing toilet training at older ages. Research is needed to discover why single parents are more successful at toilet training.

Implementation of self-organizing neural networks for visuo-motor control of an industrial robot.

The implementation of two neural network algorithms for visuo-motor control of an industrial robot (Puma 562) is reported. The first algorithm uses a vector quantization technique, the ;neural-gas' network, together with an error correction scheme based on a Widrow-Hoff-type learning rule. The second algorithm employs an extended self-organizing feature map algorithm. Based on visual information provided by two cameras, the robot learns to position its end effector without an external teacher. Within only 3000 training steps, the robot-camera system is capable of reducing the positioning error of the robot's end effector to approximately 0.1% of the linear dimension of the work space. By employing adaptive feedback the robot succeeds in compensating not only slow calibration drifts, but also sudden changes in its geometry. Hardware aspects of the robot-camera system are discussed.

Further studies on the biosynthesis of granaticin.

Experiments with cerulenin-inhibited cultures of S. violaceoruber showed conversion of dihydrogranaticin (II) into granaticin (I), but not vice versa, confirming an earlier conclusion that II is the biosynthetic precursor of I. Feeding of CH3(13)C18O2Na followed by 13C-NMR analysis of the product by the 18O shift method indicated the expected incorporation of 18O at carbons 1, 11 and 13 of I and showed that the oxygen of the pyran ring originates from C-3 and not from C-15. Analysis of I biosynthesized from 13C2H3COONa by 13C[1H, 2H] triple resonance NMR spectroscopy showed the incorporation of one atom of deuterium each at C-2 and C-4. C-16 carried a maximum of 2, not 3, atoms of deuterium. These results are discussed in terms of biosynthetic mechanisms.

Surgical re-interventions following colorectal surgery: open versus laparoscopic management of anastomotic leakage.

BACKGROUND: Increasing numbers of colorectal resections are performed laparoscopically each year. In 2010, 42% of all colorectal procedures in The Netherlands were performed laparoscopically. Although the anastomotic leakage rate is 3%-19% of all patients, little is known about laparoscopic options for re-intervention. Our study aims to evaluate the safety and feasibility of laparoscopic re-intervention compared with open surgery following colorectal surgery. PATIENTS AND METHODS: All patients who required a surgical re-intervention for an anastomotic leak, bowel perforation, or abscess after laparoscopic colorectal surgery between January 2008 and June 2012 were analyzed retrospectively. Demographic data, operative management, morbidity, hospital stay, and mortality were collected and analyzed for each patient. RESULTS: Fifty-six patients were included. Eighteen patients had a laparotomy following laparoscopy, and 38 patients had a laparoscopic re-intervention following laparoscopy. The median age was 65 years, with a median body mass index of 26 kg/m(2). Four patients had a previous laparotomy, and 73% had surgery for malignant colorectal disease. The length of hospital stay was 20 days in the laparoscopic group versus 31 days in the open group (P=.044). Six out of 38 versus 7 out of 18 patients required an additional re-intervention (P=.056). Fewer patients developed fascial dehiscence in the laparoscopic group (P=.033). In-hospital mortality was 4 out of 18 in the open group compared with 2 out of 38 in the laparoscopic group (P=.077). CONCLUSIONS: Laparoscopic re-intervention could be a safe and feasible treatment for anastomotic leakage after laparoscopic colorectal surgery. These promising results need to be further investigated in a prospective study to reduce uncertainty in the patient's condition and perioperative findings.

Peritoneal transforming growth factor beta-1 expression during prolonged laparoscopic procedures.

BACKGROUND: Laparoscopic surgery may affect peritoneal physiology. Short-term laparoscopic surgery does not affect peritoneal transforming growth factor beta (TGF-b1) expression. The current study was conducted to evaluate the hypothesis that prolonged laparoscopic surgery may affect peritoneal TGF-b1 expression. STUDY DESIGN: In the first study, 24 patients scheduled for a right colonic resection were enrolled in the trial. Twelve underwent conventional surgery (CCR) and 12 were operated on laparoscopically (LCR). In the second study, 12 patients undergoing laparoscopic gastric bypass (LGB) surgery for morbid obesity were included. Biopsies of the parietal peritoneum were taken at standardized moments during the procedures. Tissue concentrations of active and total TGF-b1 were measured by using enzyme-linked immunosorbent assays. RESULTS: During the LCR, there was a significant increase in peritoneal active TGF-b1 levels (P < 0.05). A similar, but not significant, trend was observed during the CCR. A similar pattern was seen in the total TGF-b1 concentrations during both procedures. The LGB procedure did not affect peritoneal active or total TGF-b1 concentrations. During the procedure, both the active and total TGF-b1 levels were significantly higher in the LCR, when compared to the LGB, group (P < 0.05). CONCLUSIONS: Prolonged laparoscopic surgery may affect peritoneal TGF-b1 expression, depending on the procedure performed. Considering the role of TGF-b1 in various biologic processes, including adhesiogenesis and oncology, these results may have clinical consequences.

Decreased peritoneal expression of active transforming growth factor ß1 during laparoscopic cholecystectomy with heated carbon dioxide.

BACKGROUND: Laparoscopic surgery involves the establishment of a pneumoperitoneum, mostly using carbon dioxide. Cooling of the peritoneum, due to insufflation, may traumatize the peritoneum and disturb local biological processes. The current study was performed to assess the effect of the temperature of carbon dioxide on peritoneal transforming growth factor ß1 (TGF-ß1) expression. DESIGN: Patients were randomized into 2 groups. In one group, a pneumoperitoneum was created with carbon dioxide at room temperature; in the other, with carbon dioxide at body temperature. Peritoneal biopsy specimens were taken at the start and end of surgery. SETTING: Community hospital. PATIENTS: Thirty patients scheduled for laparoscopic cholecystectomy. MAIN OUTCOME MEASURES: Tissue concentrations of total and active TGF-ß1 were measured using enzyme-linked immunosorbent assays. RESULTS: At the start of surgery, there were no significant differences between groups in the total and active fractions of TGF-ß1. At the end of the procedure, the peritoneal active TGF-ß1 concentrations were significantly lower (P = .03) in patients receiving carbon dioxide at body temperature. In contrast, the concentrations of total TGF-ß1 did not differ between groups. A slight, nonsignificant increase in total and active TGF-ß1 levels was observed in patients receiving unheated carbon dioxide. The ratio of active to total TGF-ß1 did not change during procedures, and there were no differences between groups. CONCLUSIONS: Heating of carbon dioxide, used for insufflation, to body temperature decreases the expression of active TGF-ß1 in the peritoneum. Considering the broad biological effects of TGF-ß1, including the regulation of peritoneal healing and oncological processes, this observation might have clinical repercussions.