[Show abstract][Hide abstract] ABSTRACT: Objective:
The aim of this study was to determine whether radiofrequency ablation (RFA) of the pancreas and subsequent transection of the main pancreatic duct may avoid the risk of both necrotizing pancreatitis and postoperative pancreatic fistula (POPF) formation.
Thirty-two rats were subjected to RFA and section of the pancreas over their portal vein. Animals were killed at 3, 7, 15, and 21 days (groups 0-3, respectively). Two additional control groups (sham operation and user manipulation only, respectively) of 15 days of postoperative period were considered. Postoperative complications, histological changes (including morphometric and immunohistochemical analysis), and incidence of POPF were evaluated.
A significant increase in serum amylase levels (P < 0.05) on the third postoperative day, which return to baseline levels in the following weeks, was noted in groups 0 to 3. Those groups showed a rapid atrophy of the distal pancreas by apoptosis with no signs of necrotizing pancreatitis or POPF. The distal pancreas in groups 1 to 3 compared with group 0 and control groups showed a significant increase of small islets (<1000 µm).
The rapid acinar atrophy of the distal pancreas after RFA and section of the pancreatic ducts in this model does not lead to necrotizing pancreatitis.
[Show abstract][Hide abstract] ABSTRACT: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal (non-epithelial) neoplasms of the human gastrointestinal (GI) tract. They are thought to derive from interstitial cells of Cajal (ICCs) or an ICC progenitor based on immunophenotypical and ultrastructural similarities. Because ICCs show primary cilium, our hypothesis is based on the possibility that some of these neoplastic cells could also present it. To determine this, an exhaustive ultrastructural study has been developed on four gastric GISTs. Previous studies had demonstrated considerable variability in tumour cells with two dominating phenotypes, spindly and epithelioid. In addition to these two types, we have found another cell type reminiscent of adult ICCs with a voluminous nucleus surrounded by narrow perinuclear cytoplasm with long slender cytoplasmic processes. We have also noted the presence of small undifferentiated cells. In this study, we report for the first time the presence of primary cilia (PCs) in spindle and epithelioid tumour cells, an ultrastructural feature we consider of special interest that has hitherto been ignored in the literature dealing with the ultrastructure of GISTs. We also point out the frequent occurrence of multivesicular bodies (MVBs). The ultrastructural findings described in gastric GISTs in this study appear to be relevant considering the critical roles played by PCs and MVBs recently demonstrated in tumourigenic processes.
Journal of Cellular and Molecular Medicine 05/2013; 17(7). DOI:10.1111/jcmm.12067 · 4.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The primary cilium is a non-motile cilium whose structure is 9+0. It is involved in co-ordinating cellular signal transduction pathways, developmental processes and tissue homeostasis. Defects in the structure or function of the primary cilium underlie numerous human diseases, collectively termed ciliopathies. The presence of single cilia in the central nervous system (CNS) is well documented, including some choroid plexus cells, neural stem cells, neurons and astrocytes, but the presence of primary cilia in differentiated neurons of the enteric nervous system (ENS) has not yet been described in mammals to the best of our knowledge. The enteric nervous system closely resembles the central nervous system. In fact, the ultrastructure of the ENS is more similar to the CNS ultrastructure than to the rest of the peripheral nervous system. This research work describes for the first time the ultrastructural characteristics of the single cilium in neurons of rat duodenum myenteric plexus, and reviews the cilium function in the CNS to propose the possible role of cilia in the ENS cells.
Journal of Cellular and Molecular Medicine 12/2012; 17(1). DOI:10.1111/j.1582-4934.2012.01657.x · 4.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Bone marrow-derived mesenchymal stem cells (BM-MSCs) are widely used in regenerative medicine in horses. Most of the molecular characterisations of BM-MSCs have been made at 20% O(2), a higher oxygen level than the one surrounding the cells inside the bone marrow. The present work compares the lifespan and the tri-lineage potential of equine BM-MSCs expanded in normoxia (20% O(2)) and hypoxia (5% O(2)). No significant differences were found in long-term cultures for osteogenesis and adipogenesis between normoxic and hypoxic expanded BM-MSCs. An up-regulation of the chondrogenesis-related genes (COL2A1, ACAN, LUM, BGL, and COMP) and an increase of the extracellular sulphated glycosaminoglycan content were found in cells that were expanded under hypoxia. These results suggest that the expansion of BM-MSCs in hypoxic conditions enhances chondrogenesis in equine BM-MSCs.
The Veterinary Journal 07/2012; 195(2). DOI:10.1016/j.tvjl.2012.06.008 · 1.76 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Electrical bioimpedance (BI) has been used to indirectly measure steatosis. This method has not yet been established in the clinics thus experimental studies are needed in big animals. We assessed BI to measure liver steatosis in porcine animals.
Twelve large-white × Landrace pigs weighing 35 kg were allocated to a study (n = 9) and a control group (n = 3). A special diet was used to promote steatosis among the study group: methionine deficient and choline-restricted diet that contains supplements of cholesterol, collate and excess of saturated fat. Control group animals were fed a normal diet. A new tetrapolar electrode model was used for BI measurement, which were performed during open laparotomy by inserting a probe into one of the lobes. Measurements were done in the third and fourth segments of the pig liver, placing the probe either on the surface or inserted into the parenchyma of the liver. Open biopsies were obtained at the end of the measurements. Histological samples were processed and stained with hematoxylin-eosin to estimate macrosteatosis. Pearson correlation coefficient between BI and percentage steatosis were calculated at different frequencies.
After 4 months of the special diet all the animals in the study group developed steatosis (90% to 20%), whereas none of the control group was affected. Pearson correlation coefficients between BI and percentage of steatosis were significant (0.877-0.878) with the best correlations obtained with a probe placed on the fourth segment of the liver surface and the best frequency to perform the measurements being 50 and 75 kHz.
BI is an accurate, fast method for steatosis measurements, that is easier and cheaper than either open or needle biopsy.
[Show abstract][Hide abstract] ABSTRACT: Mesenchymal stem cells (MSCs) are self-renewing, multipotent cells that could potentially be used to repair injured cartilage in diseases such as osteoarthritis (OA). In this study we used bone marrow, adipose tissue from articular and subcutaneous locations, and synovial fluid samples from 18 patients with knee OA to find a suitable alternative source for the isolation of MSCs with high chondrogenic potential. MSCs from all tissues analysed had a fibroblastic morphology, but their rates of proliferation varied. Subcutaneous fat-derived MSCs proliferated faster than bone marrow- and Hoffa's fat pad-derived MSCs, while synovial fluid-derived MSCs grew more slowly. CD36 and CD54 expression was similar across all groups of MSCs with several minor differences. High expression of these surface markers in subcutaneous fat-derived MSCs was correlated with poor differentiation into hyaline cartilage. Synovial fluid-derived MSCs presented a relatively small chondrogenic differentiation capacity while Hoffa's fat pad-derived MSCs had strong chondrogenic potential. In conclusion, MSCs from elderly patients with OA may still display significant chondrogenic potential, depending on their origin.
[Show abstract][Hide abstract] ABSTRACT: This study analyzed the phenotype and the chondrogenic differentiation of bone marrow-derived MSCs from old patients undergoing knee osteoarthritis or femoral fracture surgery. Twenty patients (12 females), with a mean age of 77.35±8.76 years, were studied. Ten patients suffered of knee osteoarthritis (OA) pathology and underwent surgery for arthroplasty, and the other 10 patients suffered femoral fracture. A comparative study of bone marrow-derived cultured human MSCs was carried out, and the main morphological parameters, proliferative activity and expression of surface markers were characterized. Bone marrow was obtained from the femur in all cases. The χ2-test, Mann-Whitney U-test, correlation coefficient and the Spearman test were applied. Bone marrow MSCs from old patients were able to differentiate into chondrocytic lineages. Proliferation and flow cytometry data showed no difference associated to the gender. No significant differences between the knee arthroplasty group or the femoral fracture group were found, except for higher CD49d % in MSC from fracture, and higher CD49f % in MSC from knee OA patients at passage one. MSCs from old patients suffering knee OA can be differentiated into chondrocytic lineages, and these present no differences with MSCs from femoral fracture patients.
Archives of gerontology and geriatrics 03/2011; 52(2):239-42. DOI:10.1016/j.archger.2010.03.026 · 1.85 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective: To study the influence of platelets on cartilage growth in articular defects in the sheep knee. Material and methods: Male Rasa Aragonesa sheep (6 months) were operated under general anaesthesia. A 4. mm diameter and 3. mm deep defect was made in the femoral trochlea in both knees. The right knee defect was filled with platelet concentrate 5. min after being activated with ClCa in group A (n=6), and similarly activated platelets + collagen scaffold in group B (n=6). Platelets were obtained by centrifuging 10. ml arterial blood from the sheep prior to the surgical procedure. The left knee defect was not filled. The sheep were sacrificed 10 weeks after surgery. Macroscopic and microscopic studies were performed. Results: In group A, hyaline cartilage was observed in the right knee defect at the end of the experiment in four cases. None of the defects of the left knees showed hyaline cartilage growth. In group B, hyaline cartilage was not observed in any right knee defect. However, in group B, all sheep showed better chondral cellularity and regeneration and lower fibrosis in the defects treated with platelets than in non-treated ones. Conclusions: This technique for articular defect reconstruction with platelets has shown satisfactory results in our study. However, collagen scaffolds may decrease this positive effect.
Revista Espanola de Cirugia Ortopedica y Traumatologia 11/2010; 54(6):378-382. DOI:10.1016/S1988-8856(10)70265-0
[Show abstract][Hide abstract] ABSTRACT: 3-Hydroxy-3-methylglutaric aciduria is a rare human autosomal recessive disorder caused by deficiency of 3-hydroxy-3-methylglutaryl CoA lyase (HL). This mitochondrial enzyme catalyzes the common final step of leucine degradation and ketogenesis. Acute symptoms include vomiting, seizures and lethargy, accompanied by metabolic acidosis and hypoketotic hypoglycaemia. Such organs as the liver, brain, pancreas, and heart can also be involved. However, the pathophysiology of this disease is only partially understood. We measured mRNA levels, protein expression and enzyme activity of human HMG-CoA lyase from liver, kidney, pancreas, testis, heart, skeletal muscle, and brain. Surprisingly, the pancreas is, after the liver, the tissue with most HL activity. However, in heart and adult brain, HL activity was not detected in the mitochondrial fraction. These findings contribute to our understanding of the enzyme function and the consequences of its deficiency and suggest the need for assessment of pancreatic damage in these patients.
[Show abstract][Hide abstract] ABSTRACT: Mesenchymal stem cells (MSCs) are multipotent cells capable of differentiating into several mesoderm lineages. They have been isolated from different tissues, such as bone marrow, adult peripheral blood, umbilical cord blood, and adipose tissue. The aim of this study was to analyze the differences in proliferation and phenotype of adipose tissue-derived MSCs from three different species, and to evaluate their capacity to differentiate into chondrocytes in vitro. A comparative study of cultured human, rabbit, and sheep mesenchymal cells from adipose tissue was carried out, and the main morphological parameters, proliferative activity, and expression of surface markers were characterized. Proliferation and flow cytometry data showed species-related differences between animal and human MSCs. Histological staining suggested that rabbit and sheep mesenchymal cells were able to differentiate into chondrocytic lineages. Human mesenchymal cells, though they could also differentiate, accomplished it with more difficulty than animal MSCs. These results could help to explain the differences in the chondrogenic capacity of sheep and rabbit MSCs when they are used as animal models compared to human mesenchymal cells in a clinical assay.
Journal of Orthopaedic Research 11/2009; 27(11):1499-507. DOI:10.1002/jor.20898 · 2.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Efficient and safe transection of biological tissue in liver surgery is strongly dependent on the ability to address both parenchymal division and hemostasis simultaneously. In addition to the conventional clamp crushing or finger fracture methods other techniques based on radiofrequency (RF) currents have been extensively employed to reduce intraoperative blood loss. In this paper we present our broad research plan for a new RF-assisted device for bloodless, rapid resection of the liver.
Our research plan includes computer modeling and in vivo studies. Computer modeling was based on the Finite Element Method (FEM) and allowed us to estimate the distribution of electrical power deposited in the tissue, along with assessing the effect of the characteristics of the device on the temperature profiles. Studies based on in vivo pig liver models provided a comparison of the performance of the new device with other techniques (saline-linked technology) currently employed in clinical practice. Finally, the plan includes a pilot clinical trial, in which both the new device and the accessory equipment are seen to comply with all safety requirements.
The FEM results showed a high electrical gradient around the tip of the blade, responsible for the maximal increase of temperature at that point, where temperature reached 100 degrees C in only 3.85 s. Other hot points with lower temperatures were located at the proximal edge of the device. Additional simulations with an electrically insulated blade produced more uniform and larger lesions (assessed as the 55 degrees C isotherm) than the electrically conducting blade. The in vivo study, in turn, showed greater transection speed (3 +/- 0 and 3 +/- 1 cm2/min for the new device in the open and laparoscopic approaches respectively) and also lower blood loss (70 +/- 74 and 26 +/- 34 mL) during transection of the liver, as compared to saline-linked technology (2 +/- 1 cm2/min with P = 0.002, and 527 +/- 273 mL with P = 0.001).
A new RF-assisted device for bloodless, rapid liver resection was designed, built and tested. The results demonstrate the potential advantages of this device over others currently employed.
[Show abstract][Hide abstract] ABSTRACT: The aim of the present article was to study the influence of platelets and different time activation on cartilage growth in articular defects in the rabbit knee.
Twelve male New Zealand rabbits (12 weeks) were divided in two groups. Under general anaesthesia, a 4 mm diameter and 2 mm deep defect was performed in medial condyles in both knees. The right knee defect was filled with platelet concentrate 5 min after being activated with ClCa in group A, and 2 min afterwards in group B. Platelets were obtained by centrifuging 10 ml arterial blood from the rabbit prior to the surgical procedure. The left knee defect was not filled. Rabbits were sacrificed 6 weeks after surgery. Macroscopic and microscopic studies were performed.
In group A, hyaline cartilage was observed in the right knee defect at the end of the experiment in five rabbits. None of the defects of the left knees showed hyaline cartilage growth. In group B, hyaline cartilage was observed in the right knee defect in only one rabbit. Nevertheless, in group B, all rabbits presented better chondral cellularity and regeneration and lower fibrosis in defects treated with platelets than in non-treated ones.
This technique for articular defect reconstruction with platelets is simple and easy, and has shown satisfactory results in our study. Platelets may be useful as an autologous source of multiple growth factors for articular defect reconstruction. Nevertheless, this is a preliminary study and further research is required.
The Knee 09/2008; 15(4):314-7. DOI:10.1016/j.knee.2008.02.006 · 1.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Radiofrequency ablation (RFA) of tumors by means of internally cooled (ICE) or multitined expandable electrodes combined with infusion of saline into the tissue may improve results. Our aim was to determine the efficacy of a previously optimized hybrid ICE system (ICE combined with infusion of saline into the tissue at a distance of 2mm) in comparison with a conventional ICE cluster electrode in porcine liver in vivo.
A total of 32 RFA were performed on a total of 10 farm pigs using two RFA systems: Group A (n=16): Cluster electrode. Group B (n=16): Hybrid system (with continuous infusion of 100ml/h of 20% NaCl at 2mm distance from the electrode shaft by an independent isolated needle). Livers were removed for macroscopic and histological assessment after the procedure. Coagulation volume, coagulation diameters, coefficient of variability (CV) of coagulation volume, sphericity ratio (SR), deposited power (DP), deposited energy (DE), deposited energy per coagulation volume (DEV) and rise of animal temperature during the procedure were compared and correlated among groups. Additionally, linear regression analysis was modeled to study the relationship between deposited energy and either coagulation volume and rise of animal temperature during the procedure in both groups.
Both coagulation volume and short diameter of coagulation were significantly greater (p<0.05) in group B compared to group A (22.7+/-11.0 cm(3) and 3.1+/-0.7 cm vs. 13.5+/-7.7 cm(3) and 2.5+/-0.5 cm, respectively). A similar CV and SR was observed among groups (57.1% and 1.4+/-0.3 vs. 48.6% and 1.3+/-0.2 for groups B and A, respectively). In group B, DE and DP were more than double group A, but DEV was nearly twice as high (9782 J/cm(3) vs. 5342 J/cm(3), for groups B and A, respectively). No significant relationship between DE and coagulation volume was encountered.
Efficacy of a single ICE may be improved with continuous infusion of saline at around 2 mm from the electrode shaft. Coagulation volume obtained with this improved system may be even greater than that obtained with a cluster electrode.
European journal of surgical oncology: the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology 07/2008; 34(7):822-30. DOI:10.1016/j.ejso.2007.09.029 · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Efficient and safe liver parenchymal transection is dependent on the ability to address both parenchymal division and hemostasis simultaneously. In this article we describe and compare with a saline-linked instrument a new radiofrequency (RF)-assisted device specifically designed for tissue thermocoagulation and division of the liver used on an in vivo pig liver model.
In total, 20 partial hepatectomies were performed on pigs through laparotomy. Two groups were studied: group A (n=8) with hepatectomy performed using only the proposed RF-assisted device and group B (n=8) with hepatectomy performed using only a saline-linked device. Main outcome measures were: transection time, blood loss during transection, transection area, transection speed and blood loss per transection area. Secondary measures were: risk of biliary leakage, tissue coagulation depth and the need for hemostatic stitches. Tissue viability was evaluated in selected samples by staining of tissue NADH.
In group A both blood loss and blood loss per transection area were lower (p=0.001) than in group B (70+/-74 ml and 2+/-2 ml/cm(2) vs. 527+/-273 ml and 13+/-6 ml/cm(2), for groups A and B, respectively). An increase in mean transection speed when using the proposed device over the saline-linked device group was also demonstrated (3+/-0 and 2+/-1cm(2)/min for group A and B, respectively) (p=0.002). Tissue coagulation depth was greater (p=0.005) in group A than in group B (6+/-2 mm and 3+/-1 mm, for groups A and B, respectively). Neither macroscopic nor microscopic differences were encountered in transection surfaces between both groups.
The proposed RF-assisted device was shown to address parenchymal division and hemostasis simultaneously, with less blood loss and faster transection time than saline-linked technology in this experimental model.
European journal of surgical oncology: the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology 06/2008; 34(5):599-605. DOI:10.1016/j.ejso.2007.05.008 · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of any device designed for liver resection is to allow blood saving and quick resections. This may be optimized using a minimally invasive approach. A radiofrequency-assisted device is described that combines a cooled blunt-tip electrode with a sharp blade on one side in an in vivo preliminary study using hand-assisted laparoscopy to perform partial hepatectomies.
Eight partial hepatectomies were performed on pigs with hand-assisted laparoscopy using the radiofrequency-assisted device as the only method for transection and hemostasis. The main outcome measures were transection time, blood loss, transection area, transection speed, blood loss per transection area, and tissue coagulation depth. The risk for biliary leak also was assessed using the methylene blue test.
The transection time was 13 +/- 7 min for a mean transected area of 34 +/- 11 cm(2). The mean total blood loss was 26 +/- 34 ml. The mean transection speed was 3 +/- 1 cm(2)/min, and the blood loss per transection area was 1 +/- 1 ml/cm(2). Abdominal examination showed no complications in nearby organs. One biliary leak was identified in one case using the methylene blue test. The transection surface was 34 +/- 11 cm(2), and the mean tissue coagulation depth was 9 +/- 2 mm. The inviability of the coagulated surface was assessed by adenine dinucleotide (NADH) staining.
The radiofrequency-assisted device has shown with a laparoscopic approach that it can perform liver resections faster and with less blood loss using a single device in a minimally invasive manner without vascular control than other commercial devices. The results show no significant differences with the same device used in an open procedure.