Influence of Peri-duodenal Non-constrictive Cuff on the Body Weight of Rats

Background Weight loss has been found to improve or re- solve cardiovascular comorbidities. There is a significant need for reversible device approaches to weight loss. Methods Non-constrictive cuff (NCC) is made of implantable silicone rubber with an internal diameter greater than the duodenum. Ten or 11 NCC were individually mounted along the duodenum from the pyloric sphincter toward the distal duodenum to cover ~22 mm in the length. Twelve Wistar rats were implanted with NCC, and six served as sham, and both groups were observed over 4 months. Six rats with implant had their NCC removed and were observed for additional 4weeks. Results The food intake decreased from 40.1 to 28.1 g/day after 4 months of NCC implant. The body weight gain decreased from 1.76 to 0.46 g/day after 4 months of NCC implant. The fasting glucose decreased from 87.7 to 75.3 mg/ dl at terminal day. The duodenal muscle layer covered by the NCC increased from 0.133 to 0.334 mm. After 4 weeks of NCC removal, the food intake, body weight gain, and fasting glucose recovered to 36.2, 2.51 g/day, and 83.9 mg/dl. The duodenal muscle layer covered by the NCC decreased to 0.217 mm. Conclusion The NCC implant placed on the proximal duode- num is safe in rats for a 4-month period. The efficacy of the NCC implant is significant for decrease in food intake, body weight gain, and fasting glucose in a normal rat model. The removal of NCC implant confirmed a cause-effect relation with food intake and hence body weight

Geometry of River Networks II: Distributions of Component Size and Number

The structure of a river network may be seen as a discrete set of nested sub-networks built out of individual stream segments. These network components are assigned an integral stream order via a hierarchical and discrete ordering method. Exponential relationships, known as Horton's laws, between stream order and ensemble-averaged quantities pertaining to network components are observed. We extend these observations to incorporate fluctuations and all higher moments by developing functional relationships between distributions. The relationships determined are drawn from a combination of theoretical analysis, analysis of real river networks including the Mississippi, Amazon and Nile, and numerical simulations on a model of directed, random networks. Underlying distributions of stream segment lengths are identified as exponential. Combinations of these distributions form single-humped distributions with exponential tails, the sums of which are in turn shown to give power law distributions of stream lengths. Distributions of basin area and stream segment frequency are also addressed. The calculations identify a single length-scale as a measure of size fluctuations in network components. This article is the second in a series of three addressing the geometry of river networks.Comment: 16 pages, 13 figures, 4 tables, Revtex4, submitted to PR

Distension-Induced Gastric Contraction is Attenuated in an Experimental Model of Gastric Restraint

Background Gastric distension has important implications for motility and satiety. The hypothesis of this study was that distension affects the amplitude and duration of gastric contraction and that these parameters are largely mediated by efferent vagus stimulation. Methods A novel isovolumic myograph was introduced to test these hypotheses. The isovolumic myograph isolates the stomach and records the pressure generated by the gastric contraction under isovolumic conditions. Accordingly, the phasic changes of gastric contractility can be documented. A group of 12 rats were used under in vivo conditions and isolated ex vivo conditions and with two different gastric restraints (small and large) to determine the effect of degree of restraint. Results The comparison of the in vivo and ex vivo contractility provided information on the efferent vagus mediation of gastric contraction, i.e., the in vivo amplitude and duration reached maximum of 12.6±2.7 mmHg and 19.8±5.6 s in contrast to maximum of 5.7±0.9 mmHg and 7.3±1.3 s in ex vivo amplitude and duration, respectively. The comparison of gastric restraint and control groups highlights the role of distension on in vivo gastric contractility. The limitation of gastric distension by restraint drastically reduced the maximal amplitude to below 2.9±0.2 mmHg. Conclusions The results show that distension-induced gastric contractility is regulated by both central nervous system and local mechanisms with the former being more substantial. Furthermore, the gastric restraint significantly attenuates gastric contractility (decreased amplitude and shortened duration of contraction) which is mediated by the efferent vagus activation. These findings have important implications for gastric motility and physiology and may improve our understanding of satiety

Using machine learning to characterize heart failure across the scales

Heart failure is a progressive chronic condition in which the heart undergoes detrimental changes in structure and function across multiple scales in time and space. Multiscale models of cardiac growth can provide a patient-specific window into the progression of heart failure and guide personalized treatment planning. Yet, the predictive potential of cardiac growth models remains poorly understood. Here, we quantify predictive power of a stretch-driven growth model using a chronic porcine heart failure model, subject-specific multiscale simulation, and machine learning techniques. We combine hierarchical modeling, Bayesian inference, and Gaussian process regression to quantify the uncertainty of our experimental measurements during an 8-week long study of volume overload in six pigs. We then propagate the experimental uncertainties from the organ scale through our computational growth model and quantify the agreement between experimentally measured and computationally predicted alterations on the cellular scale. Our study suggests that stretch is the major stimulus for myocyte lengthening and demonstrates that a stretch-driven growth model alone can explain 52.7% of the observed changes in myocyte morphology. We anticipate that our approach will allow us to design, calibrate, and validate a new generation of multiscale cardiac growth models to explore the interplay of various subcellular-, cellular-, and organ-level contributors to heart failure. Using machine learning in heart failure research has the potential to combine information from different sources, subjects, and scales to provide a more holistic picture of the failing heart and point toward new treatment strategies

Critical contribution of KV1 channels to the regulation of coronary blood flow

Ion channels in smooth muscle control coronary vascular tone, but the mechanisms require further investigation. The purpose of this study was to evaluate the functional role of KV1 channels on porcine coronary blood flow by using the selective antagonist correolide. KV1 channel gene transcripts were found in porcine coronary arteries, with KCNA5 (encoding KV1.5) being most abundant (P<0.001). Immunohistochemical staining demonstrated KV1.5 protein in the vascular smooth muscle layer of both porcine and human coronary arteries, including microvessels. Whole-cell patch clamp experiments demonstrated significant correolide-sensitive (1–10 µM) current in coronary smooth muscle. In vivo studies included direct intracoronary infusion of vehicle or correolide into a pressure-clamped left anterior descending artery of healthy swine (n=5 in each group) with simultaneous measurement of coronary blood flow. Intracoronary correolide (~0.3–3 µM targeted plasma concentration) had no effect on heart rate or systemic pressure, but reduced coronary blood flow in a dose-dependent manner (P<0.05). Dobutamine (0.3–10 µg/kg/min) elicited coronary metabolic vasodilation and intracoronary correolide (3 µM) significantly reduced coronary blood flow at any given level of myocardial oxygen consumption (P<0.001). Coronary artery occlusions (15 s) elicited reactive hyperemia and correolide (3 µM) reduced the flow volume repayment by approximately 30% (P<0.05). Taken together, these data support a major role for KV1 channels in modulating baseline coronary vascular tone and perhaps vasodilation in response to increased metabolism and transient ischemia

Improvement in the synthesis of (Z)-organylthioenynes via hydrothiolation of buta-1,3-diynes: a comparative study using NaOH or TBAOH as base

AbstractHydrothiolation of symmetrical and unsymmetrical buta-1,3-diynes with sodium organylthiolate anions in reflux, generated in situ by reacting C4H9SH with NaOH, afforded (Z)-organylthioenynes in low to good yields (25–80%). By using tetrabutylammonium hydroxide (TBAOH) as base instead of NaOH, the hydrothiolation of buta-1,3-diynes was more rapid and efficient, providing (Z)-organylthioenynes in good to excellent yields (70–95%)

Pulsatile blood flow, shear force, energy dissipation and Murray's Law

BACKGROUND: Murray's Law states that, when a parent blood vessel branches into daughter vessels, the cube of the radius of the parent vessel is equal to the sum of the cubes of the radii of daughter blood vessels. Murray derived this law by defining a cost function that is the sum of the energy cost of the blood in a vessel and the energy cost of pumping blood through the vessel. The cost is minimized when vessel radii are consistent with Murray's Law. This law has also been derived from the hypothesis that the shear force of moving blood on the inner walls of vessels is constant throughout the vascular system. However, this derivation, like Murray's earlier derivation, is based on the assumption of constant blood flow. METHODS: To determine the implications of the constant shear force hypothesis and to extend Murray's energy cost minimization to the pulsatile arterial system, a model of pulsatile flow in an elastic tube is analyzed. A new and exact solution for flow velocity, blood flow rate and shear force is derived. RESULTS: For medium and small arteries with pulsatile flow, Murray's energy minimization leads to Murray's Law. Furthermore, the hypothesis that the maximum shear force during the cycle of pulsatile flow is constant throughout the arterial system implies that Murray's Law is approximately true. The approximation is good for all but the largest vessels (aorta and its major branches) of the arterial system. CONCLUSION: A cellular mechanism that senses shear force at the inner wall of a blood vessel and triggers remodeling that increases the circumference of the wall when a shear force threshold is exceeded would result in the observed scaling of vessel radii described by Murray's Law

Exploring the Biochemical Methane Potential of Wholesale Market Waste from Jordan and Tunisia for a Future Scale-Up of Anaerobic Digestion in Amman and Sfax

3 Figuras.-- 2 TablasLocal open markets, trading fruits and vegetables, are widespread in Mediterranean countries, such as Tunisia and Jordan, producing large amounts of organic waste. Applying an anaerobic digestion process on this substrate makes it crucial to evaluate the waste mixture composition and seasonal variability properly. In this study, after defining an average composition of the fruit and vegetable waste (FVW) mixture produced in Sfax (Tunisia) and Amman (Jordan) in three seasonal intervals (autumn–winter, spring, and summer), the biochemical methane potential (BMP) of an artificially created FVW mixture was individually determined by three European institutions located in Spain, Italy, and Greece. The average BMP from all three seasons and laboratories was 286 ± 52 NmL CH4 g CODadded−1, close to the theoretical maximum yield of 350 NmL CH4 g CODadded−1, indicating a high biodegradability of the waste. Τhe biochemical methane yields of the spring mixtures were not statistically different across the three labs. The most significant differences among the BMP results were obtained for the autumn/winter and the summer mixtures used in Spain, likely due to the variety or ripeness of fruits and vegetables collected in the local markets. In the other two labs in Italy and Greece, no statistical difference was observed for the BMPs of the three season mixtures within the same lab. Therefore, not a critical difference in the biodegradability of such FVW is expected along the different seasons, indicating that the operation of a full-scale digester over a whole year would constantly benefit from the supplementation of a high biochemical methane potential feedstock. Graphical Abstract: [Figure not available: see fulltext.]This work was funded by the project entitled “Employing circular economy approach for OFMSW management within the Mediterranean countries – CEOMED” number A_B.4.2_0058, funded under the ENI CBC MED 2014–2020 programmePeer reviewe

Novel patch biomaterial treatment for colon diverticulosis in swine model

Current leading managements for diverticular disease cannot prevent the recurrence of diverticulitis, bleeding and/or other complications. There is an immediate need for developing new minimal invasive therapeutic strategies to prevent and treat this disease. Through a biomechanical analysis of porcine colon with diverticular lesions, we proposed a novel adhesive patch concept aiming at mechanical reconstruction of the diseased colon wall. This study aims to evaluate the surgical feasibility (safety and efficacy) of pulmonary visceral pleura (PVP) patch therapy using a pig model of diverticulosis. Six female Yucatan miniature pigs underwent collagenase injection (CI) for the development of diverticular lesions. The lesions in each animal either received patch implantation (treated group, n = 40 for 6 pigs) or left intact (untreated group, n = 44 for 6 pigs). The normal colonic wall in each animal received patch implantation at two spots to serve as control (n = 12 for 6 pigs). After 3 months of observation, the performance and safety of the patch treatment were evaluated through macroscopic and histological examination. We found that 95% of pouch-like herniation of the mucosa was prevented from the colon wall with the treatment. The pouch diameter was significantly reduced in the treated group as compared to the untreated group (p &lt; 0.001). The patch application caused a significant increase in the levels of collagen of the colon tissue as compared to the untreated and control groups (p &lt; 0.001). No difference was found in the lymphocyte and macrophage inflammatory infiltrate between the groups. Our results suggest that patch treatment efficiently inhibits the diverticular pouch deformation and promotes the healing of the colon wall with a normal inflammatory response, which may minimize the risk of diverticulosis reoccurrence and complications over time

The AIQ Meta-Testbed: Pragmatically Bridging Academic AI Testing and Industrial Q Needs

AI solutions seem to appear in any and all application domains. As AI becomes more pervasive, the importance of quality assurance increases. Unfortunately, there is no consensus on what artificial intelligence means and interpretations range from simple statistical analysis to sentient humanoid robots. On top of that, quality is a notoriously hard concept to pinpoint. What does this mean for AI quality? In this paper, we share our working definition and a pragmatic approach to address the corresponding quality assurance with a focus on testing. Finally, we present our ongoing work on establishing the AIQ Meta-Testbed.Comment: Accepted for publication in the Proc. of the Software Quality Days 2021, Vienna, Austri