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1.
Thorac Cardiovasc Surg ; 69(7): 649-659, 2021 Oct.
Article in English | MEDLINE | ID: mdl-31030422

ABSTRACT

BACKGROUND: Scientific attempts to create the "ideal" small diameter vascular graft have been compared with the "search of the holy grail." Prosthetic material as expanded polytetrafluoroethylene or Dacron shows acceptable patency rates to large caliber vessels, while small diameter (< 6 mm) prosthetic conduits present unacceptably poor patency rates. Vascular tissue engineering represents a promising option to address this problem. MATERIAL AND METHODS: Thirty-two female Texel-sheep aged 6 months to 2 years underwent surgical common carotid artery (CCA) interposition using different tissue-engineered vascular substitutes. Explantation of the grafts was performed 12 (n = 12) and 36 (n = 20) weeks after surgery. Ultrasound was performed on postoperative day 1 and thereafter every 4 weeks to evaluate the graft patency. RESULTS: The average length of implanted substitutes was 10.3 ± 2.2 cm. Anesthesia and surgical procedure could be performed without major surgical complications in all cases.The grafts showed a systolic blood flow velocity (BFV) of 28.24 ± 13.5 cm/s, a diastolic BFV of 9.25 ± 4.53 cm/s, and a mean BFV of 17.85 ± 9.25 cm/s. Native vessels did not differ relevantly in hemodynamic measurements (systolic: 29.77 cm/s; diastolic: 7.99 cm/s ± 5.35; mean 15.87 ± 10.75). There was no incidence of neurologic complications or subsequent postoperative occlusion. Perioperative morbidity was low and implantation of conduits was generally well tolerated. CONCLUSION: This article aims to give a precise overview of in vivo experiments in sheep for the evaluation of small diameter vascular grafts performing CCA interposition, especially with regard to pitfalls and possible perioperative complications and to discuss advantages and disadvantages of this approach.


Subject(s)
Blood Vessel Prosthesis Implantation , Blood Vessel Prosthesis , Animals , Blood Vessel Prosthesis Implantation/adverse effects , Female , Graft Occlusion, Vascular , Polytetrafluoroethylene , Sheep , Treatment Outcome , Vascular Patency
2.
BMC Surg ; 19(1): 82, 2019 Jul 08.
Article in English | MEDLINE | ID: mdl-31286901

ABSTRACT

BACKGROUND: An open abdomen is often necessary for survival of patients after peritonitis, compartment syndrome, or in damage control surgery. However, abdominal wall retraction relieves delays and complicates abdominal wall closure. The principle of the newly fascia preserving device (FPD) is the application of anteriorly directed traction on both fascial edges over an external support through a longitudinal beam to relieve increased abdominal pressure and prevent fascial retraction. METHODS: Twelve pigs were randomly divided into two groups. Both groups underwent midline laparotomy under general anesthesia. Group one was treated with the new device, group two served as controls. The tension for closing the abdominal fascia was measured immediately after laparotomy as well as at 24 and 48 h. Vital parameters and ventilation pressure were recorded. Post mortem, all fascial tissues were histologically examined. RESULTS: All pigs demonstrated increases in abdominal circumference. In both groups, forces for closing the abdomen increased over the observation period. Concerning the central closing force after 24 h we saw a significant lower force in the FPD group (14.4 ± 3 N) vs. control group (21.6 ± 5.7 N, p < 0.001). By testing the main effects using an ANOVA analysis we found a significant group related effect concerning closing force and abdominal circumference of the FDP-group vs. control group (p < 0.001; p < 0.001). The placement of the device on chest and pelvis did not influence vital parameters and ventilation pressure. Histologic exam detected no tissue damage. CONCLUSIONS: This trial shows the feasibility to prevent fascial retraction during the open abdomen by using the new device. Thus, it is expected that an earlier closure of the abdominal wall will be possible, and a higher rate of primary closure will be attained.


Subject(s)
Abdominal Wall/surgery , Fascia , Laparotomy/instrumentation , Traction/instrumentation , Wound Closure Techniques/instrumentation , Animals , Disease Models, Animal , Feasibility Studies , Female , Humans , Proof of Concept Study , Random Allocation , Swine
3.
Ther Hypothermia Temp Manag ; 9(4): 251-257, 2019 Dec.
Article in English | MEDLINE | ID: mdl-30893023

ABSTRACT

To date, the optimal cooling device for targeted temperature management (TTM) remains unclear. Water-circulating cooling blankets are broadly available and quickly applied but reveal inaccuracy during maintenance and rewarming period. Recently, esophageal heat exchangers (EHEs) have been shown to be easily inserted, revealed effective cooling rates (0.26-1.12°C/h), acceptable deviations from target core temperature (<0.5°C), and rewarming rates between 0.2 and 0.4°C/h. The aim of this study was to compare cooling rates, accuracy during maintenance, and rewarming period as well as side effects of EHEs with water-circulating cooling blankets in a porcine TTM model. Mean core temperature of domestic pigs (n = 16) weighing 83.2 ± 3.6 kg was decreased to a target core temperature of 33°C by either using EHEs or water-circulating cooling blankets. After 8 hours of maintenance, rewarming was started at a goal rate of 0.25°C/h. Mean cooling rates were 1.3 ± 0.1°C/h (EHE) and 3.2 ± 0.5°C/h (blanket, p < 0.0002). Mean difference to target core temperature during maintenance ranged between ±1°C. Mean rewarming rates were 0.21 ± 0.01°C/h (EHE) and 0.22 ± 0.02°C/h (blanket, n.s.). There were no differences with regard to side effects such as brady- or tachycardia, hypo- or hyperkalemia, hypo- or hyperglycemia, hypotension, shivering, or esophageal tissue damage. Target temperature can be achieved faster by water-circulating cooling blankets. EHEs and water-circulating cooling blankets were demonstrated to be reliable and safe cooling devices in a prolonged porcine TTM model with more variability in EHE group.


Subject(s)
Hypothermia, Induced/instrumentation , Animals , Esophagus , Hypothermia, Induced/methods , Swine
4.
Anesth Analg ; 129(5): 1224-1231, 2019 11.
Article in English | MEDLINE | ID: mdl-30418241

ABSTRACT

BACKGROUND: Targeted temperature management is a standard therapy for unconscious survivors of cardiac arrest. To date, multiple cooling methods are available including invasive intravascular cooling devices (IVDs), which are widely used in the clinical setting. Recently, esophageal heat exchangers (EHEs) have been developed providing cooling via the esophagus that is located close to the aorta and inferior vena cava. The objective was to compare mean cooling rates, as well as differences, to target temperature during maintenance and the rewarming period of IVD and EHE. METHODS: The study was conducted in 16 female domestic pigs. After randomization to either IVD or EHE (n = 8/group), core body temperature was reduced to 33°C. After 24 hours of maintenance (33°C), animals were rewarmed using a target rate of 0.25°C/h for 10 hours. All cooling phases were steered by a closed-loop feedback system between the internal jugular vein and the chiller. After euthanasia, laryngeal and esophageal tissue was harvested for histopathological examination. RESULTS: Mean cooling rates (4.0°C/h ± 0.4°C/h for IVD and 2.4°C/h ± 0.3°C/h for EHE; P < .0008) and time to target temperature (85.1 ± 9.2 minutes for IVD and 142.0 ± 21.2 minutes for EHE; P = .0008) were different. Mean difference to target temperature during maintenance (0.07°C ± 0.05°C for IVD and 0.08°C ± 0.10°C for EHE; P = .496) and mean rewarming rates (0.2°C/h ± 0.1°C/h for IVD and 0.3°C/h ± 0.2°C/h for EHE; P = .226) were similar. Relevant laryngeal or esophageal tissue damage could not be detected. There were no significant differences in undesired side effects (eg, bradycardia or tachycardia, hypokalemia or hyperkalemia, hypoglycemia or hyperglycemia, hypotension, overcooling, or shivering). CONCLUSIONS: After insertion, target temperatures could be reached faster by IVD compared to EHE. Cooling performance of IVD and EHE did not significantly differ in maintaining target temperature during a targeted temperature management process and in active rewarming protocols according to intensive care unit guidelines in this experimental setting.


Subject(s)
Heart Arrest/therapy , Hypothermia, Induced/instrumentation , Animals , Cold Temperature , Esophagus , Female , Hypothermia, Induced/adverse effects , Rewarming/instrumentation , Swine
5.
BMC Anesthesiol ; 18(1): 61, 2018 06 05.
Article in English | MEDLINE | ID: mdl-29866034

ABSTRACT

BACKGROUND: Contribution of the small intestine to systemic inflammation after cardiac arrest (CA) is poorly understood. The objective was to evaluate whether an in vivo rat model of 6 min CA is suitable to initiate intestinal ischaemia-reperfusion-injury and to evaluate histomorphological changes and inflammatory processes in the small intestinal mucosa resp. in sera. METHODS: Adult male Wistar rats were subjected to CA followed by cardio-pulmonary resuscitation. Proximal jejunum and serum was collected at 6 h, 24 h, 72 h and 7 d post return of spontaneous circulation (ROSC) and from a control group. The small intestine was evaluated histomorphologically. Cytokine concentrations were measured in jejunum lysates and sera. RESULTS: Histomorphological evaluation revealed a significant increase in mucosal damage in the jejunum at all timepoints compared to controls (p < 0.0001). In jejunal tissues, concentrations of IL-1α, IL-1ß, IL-10, and TNF-α showed significant peaks at 24 h and were 1.5- to 5.7-fold higher than concentrations at 6 h and in the controls (p < 0.05). In serum, a significant higher amount of cytokine was detected only for IL-1ß at 24 h post-ROSC compared to controls (15.78 vs. 9.76 pg/ml). CONCLUSION: CA resulted in mild small intestinal tissue damage but not in systemic inflammation. A rat model of 6 min CA is not capable to comprehensively mimic a post cardiac arrest syndrome (PCAS). Whether there is a vital influence of the intestine on the PCAS still remains unclear.


Subject(s)
Disease Models, Animal , Heart Arrest/pathology , Intestinal Mucosa/pathology , Intestine, Small/pathology , Reperfusion Injury/pathology , Animals , Cytokines/metabolism , Heart Arrest/complications , Heart Arrest/metabolism , Intestinal Mucosa/metabolism , Intestine, Small/metabolism , Male , Rats , Rats, Wistar , Reperfusion Injury/etiology , Reperfusion Injury/metabolism , Time Factors
6.
J Anat ; 232(2): 283-295, 2018 02.
Article in English | MEDLINE | ID: mdl-29193065

ABSTRACT

More frequent utilization of non-heart-beating donor (NHBD) organs for lung transplantation has the potential to relieve the shortage of donor organs. In particular with respect to uncontrolled NHBD, concerns exist regarding the risk of ischaemia/reperfusion (IR) injury-related graft damage or dysfunction. Due to their immunomodulating and tissue-remodelling properties, bone-marrow-derived mesenchymal stem cells (MSCs) have been suspected of playing a beneficial role regarding short- and long-term survival and function of the allograft. Thus, MSC administration might represent a promising pretreatment strategy for NHBD organs. To study the initial effects of warm ischaemia and MSC application, a large animal lung transplantation model was generated, and the structural organ composition of the transplanted lungs was analysed stereologically with particular respect to the blood-gas barrier and the surfactant system. In this study, porcine lungs (n = 5/group) were analysed. Group 1 was the sham-operated control group. In pigs of groups 2-4, cardiac arrest was induced, followed by a period of 3 h of ventilated ischaemia at room temperature. In groups 3 and 4, 50 × 106 MSCs were administered intravascularly via the pulmonary artery and endobronchially, respectively, during the last 10 min of ischaemia. The left lungs were transplanted, followed by a reperfusion period of 4 h. Then, lungs were perfusion-fixed and processed for light and electron microscopy. Samples were analysed stereologically for IR injury-related structural parameters, including volume densities and absolute volumes of parenchyma components, alveolar septum components, intra-alveolar oedema, and the intracellular and intra-alveolar surfactant pool. Additionally, the volume-weighted mean volume of lamellar bodies (lbs) and their profile size distribution were determined. Three hours of ventilated warm ischaemia was tolerated without eliciting histological or ultrastructural signs of IR injury, as revealed by qualitative and quantitative assessment. However, warm ischaemia influenced the surfactant system. The volume-weighted mean volume of lbs was reduced significantly (P = 0.024) in groups subjected to ischaemia (group medians of groups 2-4: 0.180-0.373 µm³) compared with the sham control group (median 0.814 µm³). This was due to a lower number of large lb profiles (size classes 5-15). In contrast, the intra-alveolar surfactant system was not altered significantly. No significant differences were encountered comparing ischaemia alone (group 2) or ischaemia plus application of MSCs (groups 3 and 4) in this short-term model.


Subject(s)
Blood-Air Barrier/pathology , Lung Transplantation/methods , Lung/pathology , Mesenchymal Stem Cell Transplantation/methods , Pulmonary Surfactants , Animals , Disease Models, Animal , Heart Arrest , Reperfusion Injury/pathology , Swine , Warm Ischemia
7.
J Vasc Surg ; 68(6S): 177S-187S.e1, 2018 12.
Article in English | MEDLINE | ID: mdl-29248244

ABSTRACT

OBJECTIVE: Despite the clinical success of large-diameter vascular grafts, synthetic grafts in small-diameter vessels are of limited use because of their poor patency rates. Previous experiments of our group provided evidence for good biocompatibility of bacterial nanocellulose (BNC) as a small-vessel graft in the carotid artery in sheep. However, the patency rate of our first-generation tubes after 3 months was only 50%. To advance our concept, we now used modified second-generation tubes with diminished wall thickness and a smoother inner surface to reduce the thrombogenic potential. The aim was to investigate mechanical characteristics of modified second-generation BNC tubes, to evaluate in vivo performance and biocompatibility, and to analyze patency rates. METHODS: We replaced the right carotid artery of 23 sheep with second-generation BNC tubes. Compared with our first-generation tubes, tubes were modified with different surface properties and diminished wall thickness (inner diameter, 4.0-5.0 mm; wall thickness, 1.0-2.5 mm; length, 100 mm) to generate a smoother inner surface with reduced thrombogenic potential and a more porous outer zone, allowing easier cell immigration. RESULTS: At the end of the investigational period, BNC tubes were explanted and grafts were processed for histopathologic analysis. Histologic analysis revealed no acute signs of foreign body reaction such as immigration of giant cells or other acute inflammatory reaction and therefore provided evidence for good biocompatibility of the second-generation tubes. However, all grafts of the sheep without antiplatelet therapy were occluded after 9 months, whereas grafts in sheep receiving dual platelet inhibition showed a patency rate of 67% (six of nine grafts). Further modified grafts revealed a patency rate of 80% (four of five grafts remained open). CONCLUSIONS: Patency rates of the second-generation tubes could be substantially improved compared with our first-generation tubes. However, poor patency rates of tissue-engineered blood vessels still limit their use in clinical studies. Further efforts in terms of in vitro and in vivo studies are essential to improve grafts of BNC.


Subject(s)
Biocompatible Materials , Blood Vessel Prosthesis Implantation/instrumentation , Blood Vessel Prosthesis , Carotid Arteries/surgery , Cellulose/chemistry , Nanoparticles , Polysaccharides, Bacterial/chemistry , Vascular Patency , Animals , Carotid Arteries/drug effects , Carotid Arteries/pathology , Carotid Arteries/physiopathology , Graft Occlusion, Vascular/pathology , Graft Occlusion, Vascular/physiopathology , Graft Occlusion, Vascular/prevention & control , Materials Testing , Models, Animal , Platelet Aggregation Inhibitors/pharmacology , Porosity , Prosthesis Design , Prosthesis Failure , Sheep, Domestic , Surface Properties , Thrombosis/pathology , Thrombosis/physiopathology , Thrombosis/prevention & control , Time Factors , Vascular Patency/drug effects
8.
Mol Metab ; 6(7): 737-747, 2017 07.
Article in English | MEDLINE | ID: mdl-28702329

ABSTRACT

OBJECTIVE: Metformin, the first line drug for treatment of type 2 diabetes, suppresses hepatic gluconeogenesis and reduces body weight in patients, the latter by an unknown mechanism. METHODS: Mice on a high fat diet were continuously fed metformin in a therapeutically relevant dose, mimicking a retarded formulation. RESULTS: Feeding metformin in pharmacologically relevant doses to mice on a high fat diet normalized HbA1c levels and ameliorated glucose tolerance, as expected, but also considerably slowed down weight gain. This was due to increased energy expenditure, since food intake was unchanged and locomotor activity was even decreased. Metformin caused lactate accumulation in the intestinal wall and in portal venous blood but not in peripheral blood or the liver. Increased conversion of glucose-1-13C to glucose-1,6-13C under metformin strongly supports a futile cycle of lactic acid production in the intestinal wall, and usage of the produced lactate for gluconeogenesis in liver. CONCLUSIONS: The reported glucose-lactate-glucose cycle is a highly energy consuming process, explaining the beneficial effects of metformin given continuously on the development of a type 2 diabetic-like state in our mice.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Energy Metabolism , Hypoglycemic Agents/pharmacology , Intestines/drug effects , Liver/drug effects , Metformin/pharmacology , Animals , Diabetes Mellitus, Type 2/etiology , Diabetes Mellitus, Type 2/metabolism , Diet, High-Fat/adverse effects , Glucose/metabolism , Hypoglycemic Agents/therapeutic use , Intestinal Mucosa/metabolism , Lactic Acid/blood , Liver/metabolism , Male , Metformin/therapeutic use , Mice , Mice, Inbred C57BL
9.
PLoS One ; 12(3): e0173229, 2017.
Article in English | MEDLINE | ID: mdl-28291783

ABSTRACT

BACKGROUND: Targeted temperature management (TTM) is widely used in critical care settings for conditions including hepatic encephalopathy, hypoxic ischemic encephalopathy, meningitis, myocardial infarction, paediatric cardiac arrest, spinal cord injury, traumatic brain injury, ischemic stroke and sepsis. Furthermore, TTM is a key treatment for patients after out-of-hospital cardiac-arrest (OHCA). However, the optimal cooling method, which is quick, safe and cost-effective still remains controversial. Since the oesophagus is adjacent to heart and aorta, fast heat-convection to the central blood-stream could be achieved with a minimally invasive oesophageal heat exchanger (OHE). To date, the optimal diameter of an OHE is still unknown. While larger diameters may cause thermal- or pressure-related tissue damage after long-term exposure to the oesophageal wall, smaller diameter (e.g., gastric tubes, up to 11mm) may not provide effective cooling rates. Thus, the objective of the study was to compare OHE-diameters of 11mm (OHE11) and 14.7mm (OHE14.7) and their effects on tissue and cooling capability. METHODS: Pigs were randomized to OHE11 (N = 8) or OHE14.7 (N = 8). After cooling, pigs were maintained at 33°C for 1 hour. After 10h rewarming, oesophagi were analyzed by means of histopathology. The oesophagus of four animals from a separate study that underwent exactly the identical preparation and cooling protocol described above but received a maintenance period of 24h were used as histopathological controls. RESULTS: Mean cooling rates were 2.8±0.4°C°C/h (OHE11) and 3.0±0.3°C °C/h (OHE14.7; p = 0.20). Occasional mild acute inflammatory transepithelial infiltrates were found in the cranial segment of the oesophagus in all groups including controls. Deviations from target temperature were 0.1±0.4°C (OHE11) and 0±0.1°C (OHE14.7; p = 0.91). Rewarming rates were 0.19±0.07°C °C/h (OHE11) and 0.20±0.05°C °C/h (OHE14.7; p = 0.75). CONCLUSIONS: OHE with diameters of 11 mm and 14.7 mm achieve effective cooling rates for TTM and did not cause any relevant oesophageal tissue damage. Both OHE demonstrated acceptable deviations from target temperature and allowed for an intended rewarming rate (0.25°C/h).


Subject(s)
Body Temperature , Cold Temperature , Esophagus/physiopathology , Hot Temperature , Animals , Female , Swine
10.
PLoS One ; 11(3): e0150759, 2016.
Article in English | MEDLINE | ID: mdl-26938613

ABSTRACT

Hypothermia is a severe, unpleasant side effect during general anesthesia. Thus, temperature surveillance is a prerequisite in general anesthesia settings during experimental surgeries. The gold standard to measure the core body temperature (Tcore) is placement of a Swan-Ganz catheter in the pulmonary artery, which is a highly invasive procedure. Therefore, Tcore is commonly examined in the urine bladder and rectum. However, these procedures are known for their inaccuracy and delayed record of temperatures. Zero-heat-flux (ZHF) thermometry is an alternative, non-invasive method quantifying Tcore in human patients by applying a thermosensoric patch to the lateral forehead. Since the porcine cranial anatomy is different to the human's, the optimal location of the patch remains unclear to date. The aim was to compare three different patch locations of ZHF thermometry in a porcine hypothermia model. Hypothermia (33.0 °C Tcore) was conducted in 11 anesthetized female pigs (26-30 kg). Tcore was measured continuously by an invasive Swan-Ganz catheter in the pulmonary artery (Tpulm). A ZHF thermometry device was mounted on three different defined locations. The smallest average difference between Tpulm and TZHF during stable temperatures was 0.21 ± 0.16 °C at location A, where the patch was placed directly behind the eye. Also during rapidly changing temperatures location A showed the smallest bias with 0.48 ± 0.29 °C. Location A provided the most reliable data for Tcore. Therefore, the ZHF thermometry patch should be placed directly behind the left temporal corner of the eye to provide a non-invasive method for accurate measurement of Tcore in pigs.


Subject(s)
Body Temperature , Thermometry/methods , Analgesia , Anesthesia , Animals , Catheterization , Catheterization, Swan-Ganz , Disease Models, Animal , Female , Forehead/pathology , Hypothermia/pathology , Pulmonary Artery , Sus scrofa , Thermometers
11.
Trop Anim Health Prod ; 48(3): 569-76, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26837619

ABSTRACT

Contagious bovine pleuropneumonia (CBPP), a severe respiratory disease, is characterized by massive inflammation of the lung especially during the acute clinical stage of infection. Tissue samples from cattle, experimentally infected with Mycoplasma mycoides subsp. mycoides Afadé, were subjected to histopathological and immunohistochemical examination in order to provide insight into innate immune pathways that shape inflammatory host responses. Lung lesions were characterized by vasculitis, necrosis, and increased presence of macrophages and neutrophils, relative to uninfected animals. The presence of three cytokines associated with innate inflammatory immune responses, namely, IL-1ß, IL-17A, and TNF-α, were qualitatively investigated in situ. Higher cytokine levels were detected in lung tissue samples from CBPP-affected cattle compared to samples derived from an uninfected control group. We therefore conclude that the cytokines TNF-α and IL-1ß, which are prevalent in the acute phase of infections, play a role in the inflammatory response seen in the lung tissue in CBPP. IL-17A gets released by activated macrophages and attracts granulocytes that modulate the acute phase of the CBPP lesions.


Subject(s)
Cattle Diseases/microbiology , Mycoplasma mycoides/isolation & purification , Pleuropneumonia, Contagious/microbiology , Animals , Cattle , Immunohistochemistry/veterinary , Interleukin-1beta/analysis , Lung/pathology , Mycoplasma mycoides/immunology , Receptors, Interleukin-17/analysis , Tumor Necrosis Factor-alpha/analysis
13.
Am J Physiol Regul Integr Comp Physiol ; 309(3): R277-85, 2015 Aug 01.
Article in English | MEDLINE | ID: mdl-26017492

ABSTRACT

Northern ungulates acclimatize to winter conditions with restricted food supply and unfavorable weather conditions by reducing energy expenditure and voluntary food intake. We investigated in a study on red deer whether rates of peptide and glucose transport in the small intestines are also reduced during winter as part of the thrifty phenotype of winter-acclimatized animals, or whether transport rates are increased during winter in order to exploit poor forage more efficiently. Our results support the latter hypothesis. We found in a feeding experiment that total energy intake was considerably lower during winter despite ad libitum feeding. Together with reduced food intake, mass of visceral organs was significantly lower and body fat reserves were used as metabolic fuel in addition to food. However, efficacy of nutrient absorption seemed to be increased simultaneously. Extraction of crude protein from forage was higher in winter animals, at any level of crude protein intake, as indicated by the lower concentration of crude protein in feces. In line with these in vivo results, Ussing chamber experiments revealed greater electrogenic responses to both peptides and glucose in the small intestines of winter-acclimatized animals, and peptide uptake into jejunal brush-border membrane vesicles was increased. We conclude that reduced appetite of red deer during winter avoids energy expenditure for unproductive search of scarcely available food and further renders the energetically costly maintenance of a large gut and visceral organs unnecessary. Nevertheless, extraction of nutrients from forage is more efficient in the winter to attenuate an inevitably negative energy balance.


Subject(s)
Deer/physiology , Eating/physiology , Energy Intake/physiology , Energy Metabolism/physiology , Feeding Behavior , Seasons , Animals , Appetite/physiology
14.
J Surg Res ; 189(2): 340-7, 2014 Jun 15.
Article in English | MEDLINE | ID: mdl-24726059

ABSTRACT

BACKGROUND: Tissue-engineered blood vessels (TEBVs) represent an innovative approach for overcoming reconstructive problems associated with vascular diseases by providing small-caliber vascular grafts. This study aimed to evaluate a novel biomaterial of bacterially synthesized cellulose (BC) as a potential scaffold for small-diameter TEBV. METHODS: Small-diameter blood vessels with a supramolecular fiber network structure consisting of tubular hydrogels from biodesigned cellulose were created using Gluconacetobacter strains and Matrix reservoir technology. BC tubes (length: 100 mm, inner diameter: 4.0-5.0 mm) were applied to replace the carotid arteries of 10 sheep for a period of 3 mo to gain further insights into (a) functional (in vivo) performance, (b) ability of providing a scaffold for the neoformation of a vascular wall and (c) their proinflammatory potential, and the (d) technical feasibility of the procedure. RESULTS: Preoperative analysis revealed a bursting strength of the grafts of approximately 800 mm Hg and suture retention strength of 4-5 N. Postexplantation analysis showed a patency rate of 50% (n = 5) and physiological performance of the patent grafts at 4, 8, and 12 wk postoperatively, compared with native arteries. Histologic analysis revealed a neoformation of a vascular wall-like structure along the BC scaffold consisting of immigrated vascular smooth muscle cells and a homogeneous endothelialization of the inner graft surface without signs of prothrombogenic or inflammatory potential. Scanning electron microscopy revealed a confluent luminal endothelial cell layer and the immigration of vascular smooth muscle cells into the BC matrix. CONCLUSIONS: BC grafts provide a scaffold for the neoformation of a three-layered vascular wall exhibit attractive properties for their use in future TEBV programs for cardiovascular surgery.


Subject(s)
Blood Vessel Prosthesis Implantation , Blood Vessel Prosthesis , Cellulose , Gluconacetobacter xylinus , Tissue Engineering , Animals , Arterioles , Feasibility Studies , Female , Foreign-Body Reaction , Materials Testing , Sheep , Tissue Scaffolds , Vascular Patency
15.
Article in English | MEDLINE | ID: mdl-23570675

ABSTRACT

trans-Resveratrol and ε-viniferin are used as dietary supplements. They are reported to be supportive in preventing arteriosclerosis and diabetes and a previous study could demonstrate an inhibitory potential on sodium-dependent glucose transport (SGLT1) in oocytes und mouse intestinal everted rings (Schulze et al., 2012, Genes Nutr. 6, S61). The in vitro effects of trans-resveratrol and ε-viniferin on intestinal glucose uptake in the porcine small intestines (Sus Scrofa) have not yet been evaluated. It was hypothesized that trans-resveratrol/ε-viniferin may have an adverse effect on porcine intestinal sodium-dependent glucose uptake. The effects on electrogenic small intestinal glucose absorption and sodium-dependent (3)H-glucose uptake in brush border membrane vesicles (BBMV) were evaluated. Pieces of mucosa were mounted into Ussing chambers and were incubated with either trans-resveratrol (0.3 mmol/L), ε-viniferin (0.3 mmol/L), or ethanol. Sodium-dependent glucose absorption into BBMV was measured. (3)H-glucose uptake studies were performed using the same concentrations of the respective substances. SGLT1-mediated glucose absorption was approximately 3-fold higher in ileum compared to jejunum. After preincubation with trans-resveratrol and ε-viniferin, glucose-induced increases of short-circuit currents were significantly decreased. BBMV-studies revealed comparable results and glucose uptake was also significantly decreased. As the glucose transport/uptake was decreased after preincubation with either trans-resveratrol or ε-viniferin this active transport mechanism was directly influenced by inhibiting the SGLT1 transport system.


Subject(s)
Benzofurans/pharmacology , Glucose/metabolism , Ileum/drug effects , Ileum/metabolism , Jejunum/drug effects , Jejunum/metabolism , Stilbenes/pharmacology , Animals , Biological Transport, Active/drug effects , Intestinal Absorption/drug effects , Intestinal Mucosa/metabolism , Male , Resveratrol , Sodium-Glucose Transporter 1/metabolism , Swine/metabolism
16.
Berl Munch Tierarztl Wochenschr ; 125(7-8): 351-8, 2012.
Article in English | MEDLINE | ID: mdl-22919930

ABSTRACT

Equine typholocolitis is a sporadic diarrheal disease causing high mortality rates. One of the risk factors responsible for this is the oral application of the macrolide antibiotic erythromycin. The aim of the present in vitro study was to investigate whether erythromycin in combination with feed restriction provokes changes in microbial hindgut metabolism and could therefore be involved in the pathogenesis of equine typhlocolitis. As application of erythromycin and feed restriction are risk factors for equine typhlocolitis, both factors were chosen to investigate their individual and combined effects on hindgut microbial metabolism. The colon simulation technique (Cositec) was used to evaluate biochemical parameters of microbial metabolism. Production rates of the acetate, proprionate and butyrate were measured as quantitative parameters of microbial fermentation. Application of erythromycin (10 mg/d) predominantly decreased the production rates of propionate. Reducing the fermentable substrate to 30% induced an even more pronounced impairment. The detrimental effects of feed restriction on the production rates of short-chain fatty acids (SCFA) were enhanced when feed restriction was combined with the application of erythromycin. Irrespective of erytrhomycin, the butyrate fermentation rate was completely inhibited by feed restriction within two days after start of restriction. The reduction in butyrate fermentation rate has to be discussed as a pathophysiological factor for the onset of acute typhlocolitis.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cecum/microbiology , Colitis/veterinary , Eating/physiology , Erythromycin/pharmacology , Horse Diseases/etiology , Animal Feed , Animals , Anti-Bacterial Agents/therapeutic use , Cecum/drug effects , Cecum/metabolism , Colitis/drug therapy , Colitis/etiology , Colitis/microbiology , Colon/drug effects , Colon/metabolism , Colon/microbiology , Erythromycin/therapeutic use , Fatty Acids, Volatile/metabolism , Fermentation , Gastrointestinal Contents/drug effects , Gastrointestinal Contents/microbiology , Horse Diseases/drug therapy , Horse Diseases/microbiology , Horses , In Vitro Techniques , Risk Factors
17.
Article in English | MEDLINE | ID: mdl-22119207

ABSTRACT

Transepithelial transport mechanisms play a key role in regulating the absorption and secretion of calcium (Ca(2+)) and inorganic phosphate (P(i)) in the gastrointestinal tract. Although intestinal disorders with imbalances in macromineral homeostasis are frequently observed in horses, available data on intestinal Ca(2+) and P(i) transport are limited. The aim of the present study was to characterize the intestinal Ca(2+) and P(i) transport functionally by using the in vitro radioisotope tracer technique with Ussing chambers and to identify components involved in Ca(2+) transport at both mRNA and protein level. Among the different intestinal segments, the duodenum showed significant and highest active Ca(2+) absorption. The findings from RT-PCR and Western blot analysis suggest that the epithelial Ca(2+) channel TRPV6, the cytosolic calcium binding protein calbindin-D(9K) and the plasma membrane calcium ATPase PMCA may be involved in active transcellular Ca(2+) transport. Regarding the P(i) transport, the results indicate significant active P(i) secretion in the jejunum, but the contributing mechanisms remain unclear. A significant inhibiting effect of ouabain as an antagonist of the basolateral Na(+)/K(+)-ATPase on the serosal-to-mucosal P(i) transport suggests a pivotal role of Na(+) in jejunal P(i) transport in the horse.


Subject(s)
Calcium/metabolism , Horses/metabolism , Intestinal Mucosa/metabolism , Phosphates/metabolism , Animals , Blotting, Western , Calbindins , DNA, Complementary/genetics , Electrophysiological Phenomena/drug effects , Epithelium/drug effects , Epithelium/metabolism , In Vitro Techniques , Intestinal Mucosa/drug effects , Intestines/drug effects , Ion Transport/drug effects , Membrane Transport Modulators/pharmacology , Ouabain/pharmacology , Plasma Membrane Calcium-Transporting ATPases/genetics , Plasma Membrane Calcium-Transporting ATPases/metabolism , Reverse Transcriptase Polymerase Chain Reaction , S100 Calcium Binding Protein G/genetics , S100 Calcium Binding Protein G/metabolism , Verapamil/pharmacology
18.
Am J Vet Res ; 72(11): 1449-55, 2011 Nov.
Article in English | MEDLINE | ID: mdl-22023122

ABSTRACT

OBJECTIVE: To determine whether administration of lidocaine during ischemia and reperfusion in horses results in concentrations in smooth muscle sufficient to protect against the negative consequences of ischemia-reperfusion injury on smooth muscle motility. ANIMALS: 12 horses. PROCEDURES: Artificial ischemia and reperfusion injury of jejunal segments was induced in vivo in conjunction with lidocaine treatment during ischemia (IRL) or without lidocaine treatment (IR). Isometric force performance was measured in vitro in IRL and IR smooth muscle preparations with and without additional in vitro application of lidocaine. Lidocaine concentrations in smooth muscle were determined by means of high-performance liquid chromatography. To assess the influence of lidocaine on membrane permeability, activity of creatine kinase and lactate dehydrogenase released by in vitro incubated tissues was determined biochemically. RESULTS: In vivo administration of lidocaine allowed maintenance of contractile performance after an ischemia and reperfusion injury. Basic contractility and frequency of contractions were significantly increased in IRL smooth muscle tissues in vitro. Additionally, in vitro application of lidocaine achieved further improvement of contractility of IR and IRL preparations. Only in vitro application of lidocaine was able to ameliorate membrane permeability in smooth muscle of IR and IRL preparations. Lidocaine accumulation could be measured in in vivo treated samples and serum. CONCLUSIONS AND CLINICAL RELEVANCE: In vivo lidocaine administration during ischemia and reperfusion had beneficial effects on smooth muscle motility. Initiating lidocaine treatment during surgery to treat colic in horses may improve lidocaine's prokinetic features by protecting smooth muscle from effects of ischemia and reperfusion injury.


Subject(s)
Anesthetics, Local/therapeutic use , Horse Diseases/drug therapy , Jejunum/pathology , Lidocaine/therapeutic use , Muscle, Smooth/drug effects , Reperfusion Injury/veterinary , Anesthetics, Local/analysis , Anesthetics, Local/blood , Anesthetics, Local/pharmacokinetics , Animals , Chromatography, High Pressure Liquid/veterinary , Colic/drug therapy , Colic/pathology , Colic/veterinary , Creatine Kinase/metabolism , Female , Horse Diseases/pathology , Horses , Infusions, Intravenous/veterinary , Isometric Contraction , Jejunum/drug effects , L-Lactate Dehydrogenase/metabolism , Lidocaine/analysis , Lidocaine/blood , Lidocaine/pharmacokinetics , Male , Muscle, Smooth/blood supply , Muscle, Smooth/pathology , Reperfusion Injury/drug therapy , Reperfusion Injury/pathology
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