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Applications of finite element simulation in orthopedic and trauma surgery

World Journal of Orthopedics 2012年第4期3卷 25-41页

作者： Antonio Herrera Elena Ibarz José Cego?ino Antonio Lobo-Escolar sergio Puértolas Enrique López Jesús Mateo Luis Gracia Department of Orthopaedic and Trauma surgery Miguel Servet University HospitalMedicine SchoolUniversity of Zaragoza Department of Mechanical Engineering University of Zaragoza

Research in different areas of orthopedic and trauma surgery requires a methodology that allows both a more economic approach and the ability to reproduce different situations in an easy way. simulation models have been introduced recently in bioengineering and could become an essential tool in the study of any physiological unity, regardless of its complexity. The main problem in modeling with finite elements simulation is to achieve an accurate reproduction of the anatomy and a perfect correlation of the different structures, in any region of the human body. Authors have developed a mixed technique, joining the use of a three-dimensional laser scanner Roland Picza captured together with computed tomography(CT) and 3D CT images, to achieve a perfect reproduction of the anatomy. Finite element(FE) simulation lets us know the biomechanical changes that take place after hipprostheses or osteosynthesis implantation and biological responses of bone to biomechanical changes. The simulation models are able to predict changes in bone stress distribution around the implant, so allowing preventing future pathologies. The development of a FE model of lumbar spine is another interesting application of the simulation. The model allows research on the lumbar spine, not only in physiological conditions but also simulating different load conditions, to assess the impact on biomechanics. Different degrees of disc degeneration can also be simulated to determine the impact on adjacent anatomical elements. Finally, FE models may be useful to test different fixation systems, i.e., pedicular screws, interbody devices or rigid fixations compared with the dynamic ones. We have also developed models of lumbar spine and hip joint to predict the occurrence of osteoporotic fractures, based on densitometric determinations and specific biomechanical models, including approaches from damage and fracture mechanics. FE simulations also allow us to predict the behavior of orthopedic splints applied to the correction of deformities, providing the

关键词： Finite element simulation Hip prosthesis Lumbar spine Lumbar fixations Osteoporotic fractures splints

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Probiotic Lactic Acid Bacteria: A Review

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Food and Nutrition sciences 2014年第18期5卷 1765-1775页

作者： Emiliano J. Quinto Pilar Jiménez Irma Caro jesús Tejero Javier mateo Tomás Girbés Department of Food science and Nutrition Faculty of Medicine and CINAD (Centro de Investigación en Nutrición Alimentación y Dietética Edificio Lucia) University of Valladolid Valladolid Spain Department of Food Hygiene and Technology Faculty of Veterinary Medicine University of León León Spain

Lactic acid bacteria (LAB) play a critical role in food production and health maintenance. There is an increasing interest in these species to reveal the many possible health benefits associated with them. The actions of LAB are species and strain specific, and depend on the amount of bacteria available in the gastrointestinal tract. Consumers are very concerned of chemical preservatives and processed foods. However, products with or processed with LAB are accepted as a natural way to preserve food and promote health. This paper aimed to review the recent data in regard to the role of probiotic LAB in the preservation of foods, in the immunomodulation in the gastrointestinal tract, and in its health

关键词： Lactic Acid Bacteria Probiotic Gastrointestinal Tract Health

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Male osteoporosis: A review

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World Journal of Orthopedics 2012年第12期3卷 223-234页

作者： Antonio Herrera Antonio Lobo-Escolar Jesús Mateo Jorge Gil Elena Ibarz Luis Gracia Department of Orthopedic and Trauma surgery Miguel Servet University Hospital 50009 Zaragoza Spain Department of Mechanical Engineering University of Zaragoza 50009 Zaragoza Spain

Osteoporosis in men is a heterogeneous disease that has received little attention.However,one third of worldwide hip fractures occur in the male population.This problem is more prevalent in people over70 years of age.The etiology can be idiopathic or secondary to hypogonadism,vitamin D deficiency and inadequate calcium intake,hormonal treatments for prostate cancer,use of toxic and every disease or drug use that alters bone metabolism.Risk factors such as a previous history of fragility fracture should be assessed for the diagnosis.However,risk factors in men are very heterogeneous.There are significant differences in the pharmacological treatment of osteoporosis between men and women fundamentally due to the level of evidence in published trials supporting each treatment.New treatments will offer new therapeutic prospects.The goal of this work is a revision of the present status knowledge about male osteoporosis.

关键词： Male osteoporosis skeleton involution Etiology Fracture risk Osteoporosis Non-pharmacological treatments Pharmacological treatments

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Instability of the lumbar spine due to disc degeneration. A finite element simulation

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Advances in Bioscience and Biotechnology 2013年第4期4卷 548-556页

作者： Elena Ibarz Yolanda Más Jesús Mateo Antonio Lobo-Escolar Antonio Herrera Luis Gracia Aragón Health sciences Institute Zaragoza Spain Aragón Institute for Engineering Research (I3A) Zaragoza Spain Department of Mechanical Engineering University of Zaragoza Zaragoza Spain Department of Orthopaedic surgery and Traumatology Miguel Servet University Hospital Zaragoza Spain Department of surgery University of Zaragoza Zaragoza Spain

Low back pain, which most common cause is degenerative disc disease, currently represents a serious problem due to its socio-economic repercussions. Different factors are involved in the degenerative process, being the most common: the loads on the spine, repeated flexion movements and individual genetic characteristics. Nowadays, there is no agreement on whether instability is the main cause of low back pain, or only one reason among many, and on whether increased spinal mobility, associated with instability, occurs either locally or at the lumbar spine as a whole. In this work, the simulation of disc degeneration is based on a finite element model of lumbar spine. A parametric study based on mechanical properties was established, for each lumbar spine movement, by evaluating the disc degeneration in 10% steps, from healthy disc to maximum degeneration. The results show as general trend a progressive mobility increase as the disc degeneration level raises. As main conclusion, disc degeneration causes increased mobility at all vertebral levels, with moderate values for incipient degeneration and much higher values for advanced degeneration, affecting more severely to the levels closest to degenerated disk. The great mobility increase detected at L5 could explain the instability detected as a clinical symptom.

关键词： Lumbar spine Finite Elements Biomechanics Kinematics Mobility Disc Degeneration

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Probability of Osteoporotic Vertebral Fractures Assessment Based on DXA Measurements and Finite Element simulation

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Advances in Bioscience and Biotechnology 2014年第6期5卷 527-545页

作者： Enrique López Elena Ibarz Antonio Herrera Jesús Mateo Antonio Lobo-Escolar sergio Puértolas Luis Gracia Aragón Health sciences Institute Zaragoza Spain Department of Design and Manufacturing Engineering University of Zaragoza Zaragoza Spain Department of Mechanical Engineering University of Zaragoza Zaragoza Spain Department of Orthopaedic surgery and Traumatology Miguel Servet University Hospital Zaragoza Spain Department of surgery University of Zaragoza Zaragoza Spain

Osteoporotic vertebral fractures represent major cause of disability, loss of quality of life and even mortality among the elderly population. Decisions on drug therapy are based on the assessment of risk factors for fracture, from bone mineral density measurements. The combination of biomechanical models with clinical studies could better estimate bone strength and support the specialists in their decision. A model to assess the probability of fracture, based on the Damage and Fracture Mechanics has been developed, evaluating the mechanical magnitudes involved in the fracture process from clinical bone mineral density measurements. The model is intended for simulating the degenerative process in the skeleton, with the consequent lost of bone mass and hence the decrease of its mechanical resistance which enables the fracture due to different traumatisms. Clinical studies were chosen, both in non-treatment conditions and receiving drug therapy, and fitted to specific patients according their actual bone mineral density measures. The predictive model is applied in a finite element simulation of the lumbar spine. The fracture zone would be determined according loading scenario (fall, impact, accidental loads, etc.), using the mechanical properties of bone obtained from the evolutionary model corresponding to the considered time. Bone mineral density evolution in untreated patients and in those under different treatments was analyzed. Evolutionary curves of fracture probability were obtained from the evolution of mechanical damage. The evolutionary curve of the untreated group of patients presented a marked increase of the fracture probability, while the curves of patients under drug treatment showed variable decreased risks, depending on the therapy type. The finite element model allowed obtaining detailed maps of damage and fracture probability, identifying high-risk local zones at vertebral body, which are the usual localization of osteoporotic vertebral fractures. The developed model is suitable for being used in

关键词： Osteoporosis Osteoporotic Vertebral Fracture Predictive Model Finite Elements Fracture Risk Fracture Probability

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Clinical value of rapid urine trypsinogen-2 test strip, urinary trypsinogen activation peptide, and serum and urinary activation peptide of carboxypeptidase B in acute pancreatitis

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World Journal of Gastroenterology 2005年第46期11卷 7261-7265页

作者： jesús sáez Juan Martínez Celia Trigo José sánchez-Payá Luis Compay Raquel Laveda Pilar Grió Cristina García Miguel Pérez-mateo section of Gastroenterology and Department of Internal Medicine Hospital General Universitario de Alicante Alicante Spain service of Clinical Laboratory Hospital General Universitario de Alicante Alicante Spain service of Preventive Medicine Hospital General Universitario de Alicante Alicante Spain section of Gastroenterology and Department of Internal MedicineHospital General Universitario de Alicante AlicanteSpain

AIM: To assess the usefulness of urinary trypsinogen-2 test strip, urinary trypsinogen activation peptide (TAP),and serum and urine concentrations of the activation peptide of carboxypeptidase B (CAPAP) in the diagnosisof acute pancreatitis.METHODs: Patients with acute abdominal pain and hospitalized within 24 h after the onset of symptoms were prospectively studied. Urinary trypsinogen-2 was considered positive when a clear blue line was observed (detection limit 50 μg/L). Urinary TAP was measured using a quantitative solid-phase ELIsA, and serum and urinary CAPAP by a radioimmunoassay method.REsULTs: Acute abdominal pain was due to acute pancreatitis in 50 patients and turned out to be extrapancreatic in origin in 22 patients. Patients with acute pancreatitis showed significantly higher median levels of serum and urinary CAPAP levels, as well as amylase and lipase than extrapancreatic controls. Median TAP levels were similar in both groups. The urinary trypsinogen-2 test strip was positive in 68% of patients with acute pancreatitis and 13.6% in extrapancreatic controls (Ps the most reliable test for the diagnosis of acute pancreatitis (sensitivity 66.7%, specificity 95.5%, positive and negative predictive values 96.6% and 56.7%, respectively), with a 14.6 positive likelihood ratio for a cut-off value of 2.32 nmol/L.CONCLUsION: In patients with acute abdominal pain,hospitalized within 24 h of symptom onset, CAPAP in serum and urine was a reliable diagnostic marker of acute pancreatitis. Urinary trypsinogen-2 test strip showed a clinical value similar to amylase and lipase.Urinary TAP was not a useful screening test for the diagnosis of acute pancreatitis.

关键词：尿胰蛋白酶原-2 羧肽酶活化肽胰腺炎

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Comparative Analysis of the Antioxidant and Free-Radical scavenging Activities of Different Water-soluble Extracts of Green, Black and Oolong Tea samples

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Food and Nutrition sciences 2014年第22期5卷 2157-2166页

作者： jesús Tejero sara Gayoso Irma Caro Damián Cordoba-Diaz Javier mateo José E. Basterrechea Tomás Girbés Pilar Jiménez Nutrició n y Bromatologí a Facultad de Medicina and CINAD (Centro de Investigaci&oacute n en Nutrició n Alimentaci&oacute n y Dietética Edificio Lucia-Parque Cientí fico) Universidad de Valladolid Valladolid Spain Farmacia y Tecnologí a Farmacéutica Facultad de Farmacia and IUFI (Instituto Universitario de Farmacia Industrial) Universidad Complutense de Madrid Madrid Spain Higiene de los Alimentos y Tecnologí a Facultad de Veterinaria Universidad de Le&oacute n Le&oacute n Spain

Extracts of 40 green, black or oolong high quality tea samples from China, Japan or India among others, have been prepared according to the manufacturer instructions and assayed for total polyphenols content using the Folin-Ciocalteu phenol reagent. In addition, the antioxidant activity was assessed by the CUPRAC method and the free-radical scavenging activity was determined using the antioxidant-promoting decay of the stable free-radical DPPH. Caffeine and the most important catechins were identified using RP-HPLC previously validated method. Results from this study suggest that teas, even though they content similar amounts of caffeine, differ considerably in polyphenolic content and therefore in antioxidant and free-radical scavenging activities, depending on the part of the plant used and the process applied to the material for the preparation of the final tea presentation. Correlations among Folin-Ciocalteau’s reactivity of tea samples, the neocuproine reactivity, the DPPH decolourization and the HPLC analysis suggest that the antioxidant activity is due essentially to polyphenolic compounds present in teas, mainly EGCG. The best extraction method of tea powder was the one indicated by dealers. In general, the richest samples belong to green teas and the poorest samples belong to the black teas.

关键词： Tea Polyphenols Antioxidants Free-Radical scavenging

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