Dilantin

By T. Sancho. Edinboro University of Pennsylvania.

Eventually buy discount dilantin 100mg, I found the biomolecular model of disease applicable only to a narrow segment of patients who seek medical care order 100mg dilantin otc. We need to draw clear distinctions between the reductionist research model and the need for an ex- panded clinical model that encompasses the psychological and social aspects of human beings. Human biology and clinical med- icine overlap, but they are also quite different and are too often confused. When I did, I was heavily influenced by his writings and began to understand some of the clinical problems I was encountering. Balint studied general practitioners for several years in the United Kingdom as if they were pharmacologic agents. He was examining the correct dos- age, underdosage, overdosage, and duration of action of physicians themselves as a drug. Balint developed the term apostolic function of a physician to describe the beliefs and teachings of physicians as these affected their relationships with their patients. Of the apostolic function, Balint (1955, 684) writes: We meant that every doctor has a set of fairly firm beliefs as to which illnesses are acceptable and which are not; how much pain, suffering, fears, and deprivations a patient should tolerate, and when he has the right to ask for help and relief: how much nuisance the patient is allowed to make of himself and to whom, etc. Tese beliefs are hardly ever stated explicitly but are nevertheless very strong. Tey compel the doctor to do his best to convert all of his patients to accept his own standards and to be ill or to get well according to them. Te effect of the apostolic function on the ways the doctor can administer himself to his patients is fundamental. Abram and I jointly published a chapter in his book Basic Psychiatry for the Primary Care Physician. It is this narrow version under which I had attempted to function during the early years after I graduated from medical school. Te hypothetical statement says: I believe my job as a physician is to find and classify each disease of my patient, prescribe the proper medicine, or recommend the appropriate surgical procedure. Medical disease (real or organic disease) is caused by a single physi- cochemical defect such as by invasion of the body by a foreign agent (virus, bacterium, or toxin) or from some metabolic de- rangement arising within the body. It was only by an accumulation of confounding clinical expe- riences, described in the early chapters of this book, that I came to reject the narrow model. When I was in full-time private practice in Selma, Alabama, in the early 1960s, the senior partner in my practice group got pneu- monia. For about three months, I saw all of his patients in addition to my own growing practice. I was surprised to find that many of his patients carried diagnoses of diseases they did not have. Upon my return to Birmingham and full-time academic life in 1963, I continued to encounter patients who carried diagnoses of nonexistent disease. I wrote a satire called the Art and Science of Nondisease and published it in the New England Journal of Medi- cine (Meador 1965). I thought of it as a tongue-in-cheek poke at the foibles of medical practice. Te continued responses to that article tell me that I hit on some deep nerve in the way medicine is prac- ticed—that I uncovered some fundamental problem. I remained puzzled by what to make of this seemingly com- mon error in medical practice until I began to write this book. It is now clear to me that making a false diagnosis of a disease is a con- sequence of adhering rigidly to the narrow biomolecular model. Tis view of diseases says, If a patient has symptoms in the body, then there must be a disease of the body. However, there is not a de- finable medical disease behind every physical symptom. In this book, I tell the stories of a series of patients who had symptoms in their bodies but who had no demonstrable medical disease to explain them. Additionally, I raise and explore answers Introduction xiii to a set of questions about patients who carry diagnoses of diseases they do not have: 1.

The close proximity of astrocytes to neurons is essential to neuronal long-term survival buy dilantin 100mg free shipping. One strategy to achieve the benefits of astrocytes while poten- tially obviating their deleterious e¤ects is to develop a method for selective attach- ment of neurons and glia to specific compartments of a neural prosthesis discount 100mg dilantin overnight delivery. Our initial approach will involve di¤erential surface coatings of specific cell adhesion molecules, such as decapeptide (KHIFSDDSSE) or L1, to bind glial cells and repulsion mole- cules, such as the integrin-ligand peptide RGDS (arginine-glycine-aspartate-serine) or the amino acids serine or polyethylene glycol (Mohajeri et al. An alternative approach could use inhibitors of glial proliferation (cycloheximide) at the time of implantation to permit neuronal contact and adhesion with the neuro- prosthetic electrodes to occur and then allow normal glial proliferation to proceed. The risk of this approach is that while antiproliferative agents would inhibit the pro- liferative response of activated and hence inflammatory glial cells, they would also inhibit proliferation of neural progenitor and stem cells, thereby potentially eliminat- ing a crucial source of neurons necessary for successful interfacing between the bio- mimetic device and the brain tissue surrounding the device. A third approach could be to couple surface coatings of CAMs and repulsion molecules with hydrogels for release of chondroitinase to inhibit the chondroitin sulfate proteoglycans required for glial scarring and/or inflammatory response inhibitors such as vasopressin or anti-interleukin 1 (figure 11. The aforementioned strategies of creating biomimetic surfaces with membrane proteins found on the extracellular side of the membrane, such as cell adhesion mol- ecules, coupled with anti-inflammatory strategies that capitalize on the advances in neuroimmunology, may prove to be su‰cient to sustain the viability of a neural prosthesis over the lifetime of the user. Conclusions The goal of this chapter was to bring into focus several of the major challenges for the development of implantable neural prostheses that can coexist and bidirectionally communicate with living brain tissue. Although these problems are formidable, advances in the field of microelectronics, surface chemistry, materials science, neuro- immunology, neuroscience, and therapeutic formulation provide the scientific and engineering sca¤olding necessary to generate solutions to the challenges at the biotic/abiotic interface. It shows a diagrammatic representation of a multifunctional system to achieve long-term neuron survival and a neu- ronal interface with an electrode (pads or penetrating) while simultaneously suppressing glial proliferation, activation, invasion, and the ensuing inflammatory response. Conformal multisite electrode arrays can be coated with specific adhesion substrates, followed by microstamping of hydrogel matrices that contain neu- ronal survival and glial suppression factors around the electrode. Hippocampal slices can be cultured on top of the electrode-adhesion substrate-hydrogel matrix to test for optimal in vitro conditions prior to in vivo analyses. Acknowledgments This work was supported by O‰ce of Naval Research grants to T. IV HARDWARE IMPLEMENTATIONS Brain-Implantable Biomimetic Electronics as a Neural Prosthesis for 1 Hippocampal Memory Function Theodore W. One of the true frontiers in the biomedical sciences is repair of the human brain: developing prostheses for the central nervous system to replace higher thought pro- cesses that have been lost through damage or disease. The type of neural prosthesis that performs or assists a cognitive function is qualitatively di¤erent than the coch- lear implant or artificial retina, which transduce physical energy from the environ- ment into electrical stimulation of nerve fibers (Loeb, 1990; Humayun et al. Instead, we consider here a neural prosthe- sis designed to replace damaged neurons in central regions of the brain with silicon neurons that are permanently implanted into the damaged region. The replacement neurons would have the same functional properties as the damaged neurons, and would receive electrical activity as inputs and send it as outputs to regions of the brain with which the damaged region previously communicated. Thus, the prosthesis being proposed is one that would replace the computational function of damaged brain areas, and restore the transmission of that computational result to other regions of the nervous system. Although the barriers to creating intracranial, electronic neural prostheses have seemed insurmountable in the past, the biological and engineering sciences are on the threshold of a unique opportunity to achieve such a goal. The tremendous growth in the field of neuroscience has allowed a much more detailed understanding of neurons and their physiology, particularly with respect to the dynamic and adap- tive cellular and molecular mechanisms that are the basis for information processing in the brain. Likewise, there have been major breakthroughs in the mathematical 242 Theodore W. Berger and colleagues modeling of nonlinear and nonstationary systems that are allowing quantitative rep- resentations of neuron and neural system functions to include the very complexity that is the basis of the remarkable computational abilities of the brain. The con- tinuing breakthroughs in electronics and photonics o¤er opportunities to develop hardware implementations of biologically based models of neural systems that allow simulation of neural dynamics with true parallel processing, a fundamental charac- teristic of the brain, and real-time computational speed. Fundamental advances in low-power designs have provided the essential technology to minimize heat gen- eration by semiconductor circuits, thus increasing compatibility with temperature- sensitive mechanisms of the brain. Finally, complementary achievements in materials science and molecular biology o¤er the possibility of designing compatible neuron/ silicon interfaces to facilitate communication between silicon computational devices and the living brain. Essential Requirements for an Implantable Neural Prosthesis In general terms, there are six essential requirements for an implantable microchip to serve as a neural prosthesis. First, if the microchip is to replace the function of a given brain tissue, it must be truly biomimetic; that is, the neuron models incorpo- rated in the prosthesis must have the properties of real biological neurons. This demands a fundamental understanding of the information-processing capabilities of neurons that is experimentally based. Second, a neural prosthesis is desired only when a physiological or cognitive function is detectably impaired (according to neurological or psychiatric criteria).