By Q. Bandaro. High Point University. 2018.
Ultrasonic waves can be compared to a strong wind striking biological materials with power proportional to ultrasound intensity buy viagra 25 mg otc erectile dysfunction doctor miami. This wind causes order viagra 25mg on line erectile dysfunction wiki, depending on its strength, displacements, ruptures, and variations in the shape of biological molecules. The mechanical drive may cause displacement of macromolecules out of their normal cell compartments and, thus, disorders in cell function. Biological functions of macromolecules are conditioned by their presence in the site of reaction. When mechanical waves achieve enough strength, macromolecule ﬂexion and even rupture can occur with its consequent functional loss. Formation of highly reactive oxygen free radicals is another mechanism involved in the damage of surrounding biological structures. The most common process of ultrasound micromechanical activity is protein denaturation. SURGICAL TREATMENT E: ULTRASONIC HYDROLIPOCLASIS & 243 From a stereochemical viewpoint, proteins are made up of primary, secondary, and tertiary structures. Primary structures are possible thanks to peptide bonds—covalent bonds requiring high energy supply to be split. On the other hand, the remaining struc- tures are possible thanks to weak bonds (polar, or hydrogen) requiring a certain spatial closeness of the constituent groups. Because they are weak bonds, weak energy is enough to split them and to separate the constituent chemical groups. Spatial distance hinders, then, the new formation of the same bonds. This causes serious functional damage because it is precisely due to secondary and tertiary structures that proteins form active loci. The thermic effects of ultrasound are attributable to the so-called Joule effect. The mechanical waves of ultrasound cause molecular movements that increase the kinetic energy of molecules: according to Joule’s law, the potential energy of electric charges in movement is partly ceded under the form of heat. This causes the temperature of biologi- cal materials to increase, and when the physiological value of 37 C (98. Cavitation occurs in liquids subjected to ultrasound at frequencies higher than 900 kHz. This determines the formation of vapor and air bubbles inside the liquids; a real explosion of these microbubbles is produced damaging the surrounding structures. For cavitation to occur, tissues require ultrasound intensities 1000 times higher than liquids. However, it must be considered that the human body is made up of 60% water and has anatomical cavities (cerebral ventricles, heart, great vessels, gall bladder, and urinary bladder) with liquid contents. It is known that the application of ultrasound on biological materials soaked in water causes notable damage. This damage does not occur through the cavitation of bio- logical materials, but through the explosion of the microbubbles produced by the cavita- tion of the water present. Water inﬁltration in tissues and the subsequent application of ultrasound cause water cavitation, microbubble formation and explosion, and rupture of surrounding bio- logical materials. It is understood that the more delicate structures (endothelial cells, adipose cells, etc. Ultrasonic hydrolipoclasis (ILCUS) is employed to cause volumetric reduction of tis- sues made up of structures highly sensitive to the mechanical damage resulting from the microbubble explosions caused by cavitation. Indications should be limited to the nonsur- gical treatment of lipomas and to the treatment of localized adiposities as an alternative to liposuction. Because of the inverse relation between ultrasound frequency and penetration, its beam activity is limited to the more superﬁcial strata of the body. In addition, cavitation of the inﬁltrated liquid absorbs quite a large amount of energy so that the ultrasound power that penetrates beneath becomes irrelevant.
This constitutes a cauldron for cultivating the spirit in the practice called the sealing of the five sense organs purchase viagra 100mg online impotence prostate. Pineal Gland (Human Compass) The pineal gland is a cone-shaped body cheap viagra 100 mg otc guaranteed erectile dysfunction treatment, reddish in color, about half an inch in length, and not much larger than a grain of wheat. It is attached to, and situated over, the third ventricle of the brain, weighing about two grains. It is composed, in part, of nerve cells containing a pigment similar to that present in the cells of the retina. This strengthens the argument for its function as an eye in earlier animal species. In the Taoist terminology, the Niwan-Kung corresponds to this gland. In the cauldron, it is considered to cultivate the highest level of the spirit in the practice: Congress of Heaven. When the gland is fully developed it will tell us where our destination is. The material contained herein is not intended to provide specific advice or recommendations for any specific situation. Trademark notice: Product or corporate names may be trademarks or registered trademarks and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress. ISBN: 0-8247-4294-X This book is printed on acid-free paper. For more information, write to Special Sales/Professional Marketing at the headquarters address above. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage and retrieval system, without permission in writing from the publisher. Current printing (last digit): 1 PRINTED IN THE UNITED STATES OF AMERICA Preface This reference text Biomaterials in Orthopedics contains cutting-edge presentations by leading authorities dealing with the critical issues surrounding materials for bone repair and reconstruc- tion. The chapters cover the use of a wide range of biomaterials from bioabsorbables to ceramics and metals. With input from scientific, engineering, and clinical professionals the text highlights the multi-disciplinary nature of biomaterial development and application. Beginning with discussions of the fundamental aspects of biocompatibility and interfacial phenomena, the text then moves on to discussions of emerging bioabsorbable materials and novel advancements in time-honored ceramic and metallic bone repair biomaterials. Applications to traditional orthopedic sectors are considered along with those to oral and maxillofacial recon- struction and ever-challenging spinal applications. Despite the long history of orthopedic bioma- terials, it is amazingly clear that the field begs for new solutions to clinical demands. Active lifestyles and aging populations drive a market that showcases the need for a strengthening in the battery of biomaterials in the surgeon’s toolcase. This text offers a wealth of valuable data and experience that will be of use to all bioengi- neers, materials scientists, and clinicians concerned with the properties, performance, and use of bone repair biomaterials—from research engineers faced with designing materials to surgeons interested in material biocompatibility and performance. The chapters, some of which include case studies, provide rich insights into our experiences today with a broad spectrum of contribut- ing authors. The book focuses on discussion of the following: Issues of biomaterial performance and biocompatibility The rationale for designing bioabsorbable biomaterials for bone repair Techniques for enhancing the surface properties of biomaterials Developments in mechanical optimization of orthopedic biomaterials, and Advances in fillers, cements and devices. The orthopedic industry is currently one of the strongest market performers, and biomateri- als are a key ingredient to this dynamic growth. Optimization of orthopedic biomaterials is in a constant state of activity, as old materials fail to withstand the tests of time and modern techniques and procedures drive the demand for new materials and devices. This text highlights the aggressive approaches necessary to address this demand. Trantolo Kai-Uwe Lewandrowski Vasif Hasirci David E. Wise iii Contents Preface iii PART I: BIOCOMPATIBILITY AND THE BIOMATERIAL–TISSUE INTERFACE 1.
Insulin-sensitizing agents of acne and hirsutism [121–123] and have been intro- have recently been investigated for their role in the short duced in clinical studies order viagra 100mg with amex impotence caused by diabetes. Controlled studies have shown that metformin Antisense Molecules administration cheap viagra 25mg otc next generation erectile dysfunction drugs, by promoting body weight loss, can de- The androgen receptor is involved in the development crease fasting and stimulated plasma insulin levels. How- of acne and its expression can classically be regulated by ever, other studies have shown metformin 500 mg 3! A more elegant way is the daily to decrease insulin secretion and to reduce ovarian transient transfection of skin cells with antisense oligonu- production of 17·-hydroxyprogesterone with recovery of cleotides against the androgen receptor . The devel- spontaneous or clomifene-induced ovulation, indepen- opment of thioat- and ribosyl-antisense oligonucleotides dently of weight loss. These findings suggest a new indica- against the androgen receptor led with high specificity in a tion for metformin and present insulin-sensitizing agents transient diminished protein expression of the receptor as a novel approach in the treatment of ovarian hyperan- and to a strong inhibition of the biological activity of drogenism. Peroxisomes play an important role in regulating cellu- Such experiments are only in an initial phase. The future lar proliferation and differentiation as well as in the mod- clinical use of such highly specific compounds is depen- ulation of inflammatory mediators. In addition, peroxi- dent on several factors, among them being the effective somes have broad effects on the metabolism of lipids, hor- administration pathway and the kind of transfection sys- mones, and xenobiotics . PPAR-Á1 Despite the interest on the development of topical mRNA was also demonstrated in rat preputial gland cells treatments for acne in the last decades, systemic but not in epidermal cells. These findings are compatible treatment is still a milestone, especially in the treatment with the concepts that PPAR-Á1 gene expression plays a of moderate-to-severe scarring types of the disease. The unique role in the differentiation of sebocyte-like cells. Among all why lipoxygenase inhibitors inhibit lipid synthesis : pathogenetic factors of acne, inflammation seems to be The lipoxygenase products LTB4 and 15-HETE are natu- rediscovered and anti-inflammatory concepts seem ral ligands of PPAR-· and PPAR-Á, respectively. Despite the fact that several steroidal and non-steroidal inhibitors have been synthesized and experimented in pharmacological models, only finasteride has been extensively used for clinical purposes, namely benign prostate hyperplasia and male baldness with positive results. In women, finasteride has been used in some control trials for treatment of hirsu- tism with an objective favorable response. On the basis of experimental observations on distribution of 1 and 2 iso- enzymes in human skin, scalp and prostate, the pure 5·- 50 Dermatology 2003;206:37–53 Zouboulis/Piquero-Martin References 1 Gollnick H, Zouboulis ChC, Akamatsu H, Ku- 20 Orfanos CE, Adler YD, Zouboulis ChC: The 38 Leyden JJ: Current issues in antimicrobial rokawa I, Schulte A: Pathogenesis and patho- SAHA syndrome. Horm Res 2000;54:251– therapy for the treatment of acne. Lancet and hormonal therapy for women with difficult Revuz J: Comedonal diffusion of minocycline 1998;351:1871–1876. Dermatol Experiences 22 Madden WS, Landells ID, Poulin Y, Searles tivity syndrome with hypotension mimicking 1999;1:6–37. GE, Smith KC, Tan JK, Toole J, Zip CM, septic shock. Pediatr Dermatol 2001;18:295– 4 Piquero-Martı´n J: Acné – Manejo racional, ed Degreef H: Treatment of acne vulgaris and pre- 298. J Cutan Med Surg 2000;4(suppl 1): Jackson E, Roszman T, Goebel J: Interstitial date on the pathogenesis and treatment of acne. Derma- Azziz R: Hyperandrogenemia in patients pre- ney Dis 2001;38:E36. Fertil Steril 2001;75:889– 42 Seaman HE, Lawrenson RA, Williams TJ, Ma- 7 Stern R: Medication and medical service utili- 892. J Am Acad Derma- 24 Zouboulis ChC: Human skin: An independent associated with minocycline: A comparative tol 2000;43:1042–1048. Austr J Dermatol 2001;42: 26 Chen W, Thiboutot D, Zouboulis ChC: Cuta- Strategy of acne therapy with long-term antibi- 98–101. J Invest Dermatol, in 45 Berson DS, Shalita AR: The treatment of acne: bull JR, Boschnakow A: Sebaceous glands; in press. J Am Acad Hoath SB, Maibach H (eds): Neonatal Skin – 27 Shaw JC: Hormonal therapies in acne. Derma- oral minocycline with oral isotretinoin in se- GI: Comedogenesis: Some new aetiological, tology 1998;196:140–147. Dermatolo- 29 Zouboulis ChC, Korge B, Akamatsu H, Xia L, 47 Strauss JS, Rapini RP, Shalita AR, Konecky E, gy 2003;206:11–16.
These are the neurons that receive The reticular formation discount viagra 75mg on line coke causes erectile dysfunction, RF purchase viagra 100mg with visa erectile dysfunction at 20, is the name for a group of the various inputs to the reticular formation, neurons found throughout the brainstem. Using the ventral including those from the anterolateral system view of the brainstem, the reticular formation occupies (pain and temperature, see Figure 34), the the central portion or core area of the brainstem from trigeminal pathway (see Figure 35), as well as midbrain to medulla (see also brainstem cross-sections in auditory and visual input. These This collection of neurons is a phylogenetically old neurons are larger in size and project their set of neurons that functions like a network or reticulum, axons upward and downward. The RF receives afferents projection from the midbrain area is particularly from most of the sensory systems (see next illustration) involved with the consciousness system. Nuclei and projects to virtually all parts of the nervous system. The importance of which use the catecholamine serotonin for neu- this knowledge was discussed in reference to rotransmission. The best-known nucleus of this the clinical emergency, tonsillar herniation group is the nucleus raphe magnus, which plays (with Figure 9B). In summary, the reticular formation is connected with • Ascending projection system: Fibers from the almost all parts of the CNS. Although it has a generalized reticular formation ascend to the thalamus and inﬂuence within the CNS, it also contains subsystems that project to various nonspeciﬁc thalamic nuclei. The most clin- From these nuclei, there is a diffuse distribution ically signiﬁcant aspects are: of connections to all parts of the cerebral cortex. This whole system is concerned with con- • Cardiac and respiratory centers in the medulla sciousness and is known as the ascending retic- • Descending systems in the pons and medulla ular activating system (ARAS). These are not always tem © 2006 by Taylor & Francis Group, LLC Functional Systems 115 Ascending reticular activating system (ARAS) Locus ceruleus Lateral group Medial group Raphe nuclei Reticulo-spinal tracts FIGURE 42A: Reticular Formation 1 — Organization © 2006 by Taylor & Francis Group, LLC 116 Atlas of Functional Neutoanatomy FIGURE 42B located within the core region. These include the periaq- ueductal gray and the locus ceruleus. RETICULAR FORMATION 2 The periaqueductal gray of the midbrain (for its location see Figure 65 and Figure 65A) includes neurons that are found around the aqueduct of the midbrain (see RETICULAR FORMATION: NUCLEI also Figure 20B). This area also receives input (illustrated In this diagram, the reticular formation is being viewed but not labeled in this diagram) from the ascending sen- from the dorsal (posterior) perspective (see Figure 10 and sory systems conveying pain and temperature, the antero- Figure 40). Various nuclei of the reticular formation, RF, lateral pathway; the same occurs with the trigeminal sys- which have a signiﬁcant (known) functional role, are tem. This area is part of a descending pathway to the spinal depicted, as well as the descending tracts emanating from cord, which is concerned with pain modulation (as shown some of these nuclei. Functionally, there are afferent and efferent nuclei in The locus ceruleus is a small nucleus in the upper the reticular formation and groups of neurons that are pontine region (see Figure 66 and Figure 66A). In some distinct because of the catecholamine neurotransmitter species (including humans), the neurons of this nucleus used, either serotonin or noradrenaline. The afferent and accumulate a pigment that can be seen when the brain is efferent nuclei of the RF include: sectioned (prior to histological processing, see photograph of the pons, Figure 66). Output from this small nucleus is • Neurons that receive the various inputs to the distributed widely throughout the brain to virtually every RF are found in the lateral group (as discussed part of the CNS, including all cortical areas, subcortical with the previous illustration). In this diagram, structures, the brainstem and cerebellum, and the spinal these neurons are shown receiving collaterals cord. The neurotransmitter that is used by these neurons (or terminal branches) from the ascending ante- is noradrenaline and its electrophysiological effects at var- rolateral system, carrying pain and temperature ious synapses are still not clearly known. It has been implicated in reticular formation, at various levels. These a wide variety of CNS activities, such as mood, the reac- cells project their axons upward or downward. The nucleus gigantocellularis of the medulla, The cerebral cortex sends ﬁbers to the RF nuclei, and the pontine reticular nuclei, caudal, and including the periaqueductal gray, forming part of the oral portions, give rise to the descending tracts cortico-bulbar system of ﬁbers (see Figure 46). The nuclei that emanate from these nuclei — the medial that receive this input and then give off the pathways to and lateral reticulo-spinal pathways, part of the the spinal cord form part of an indirect voluntary motor indirect voluntary and nonvoluntary motor sys- system — the cortico-reticulo-spinal pathways (discussed tem (see Figure 49A and Figure 49B). In addition, this system is known to play an and project to all parts of the CNS. Recent extremely important role in the control of muscle tone studies indicate that serotonin plays a signiﬁ- (discussed with Figure 49B). One special nucleus CLINICAL ASPECT of this group, the nucleus raphe magnus, Lesions of the cortical input to the reticular formation in located in the upper part of the medulla, plays particular have a very signiﬁcant impact on muscle tone. This is the physiological basis nervous system at multiple levels.
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