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It has been shown that many of the axons that escape the initial injury become demyelinated cheap 80mg super levitra otc erectile dysfunction doctors in south jersey, possibly due to inflammation order 80mg super levitra impotence versus erectile dysfunction, excitotoxicity, and apoptotic death of oligodendrocytes. Demyelina- © 2005 by CRC Press LLC tion causes redistribution of sodium channels and unmasks potassium channels, both of which interfere with the conduction of action potentials. Allowing even a small number of neurons to escape the initial injury could produce profound functional benefit. Conversely, inducing even a small population of neurons to regenerate effectively could restore a significant amount of neurolog- ical function. The neurons confined to the CNS do not upregulate the expression of growth-associated genes unless they are injured close to their cell bodies. One approach to repairing an injured spinal cord would be to find ways to turn on the regenerative machinery and effectively enhance axonal regrowth. A second approach would be to bridge the injury gap or replace cells with neural grafts, stimulating axon regrowth across the bridge or providing new cellular elements that could promote regeneration. Expression of the GAP-43 and CAP-23 genes in transgenic mice is sufficient to induce a regenerative response following isolated CNS injury. Other researchers have found that inosine, perhaps through the activation of these same kinases, can induce the regeneration of layer 5 pyramidal axons and promote reinnervation following SCI in rats. The most promising of these appears to be NT-3, which not only promotes the © 2005 by CRC Press LLC regeneration of neurons following axotomy, but also minimizes atrophy and cell loss following SCI. Removing myelin from the CNS or using grafts lacking central myelin, for example, are two ways to promote regeneration. Three inhibitory molecules identified thus far are all components of CNS myelin: nogo, myelin-associated glycoprotein, and oligodendrocyte myelin glycoprotein. Despite this clearly erroneous regeneration, the animals regained use of their affected limbs, suggest- ing a role for enhanced plasticity. Hopefully, the interests of pharmaceutical companies in inhibitors of nogo, will soon bring this mode of therapy to human trials. These are expressed on astrocytes, oligodendrocyte precursors, and meningeal cells, which are all avidly recruited to the site of a CNS injury. Recently, the intrathecal infusion of one such enzyme, chondroitinase ABC, following SCI in rats was shown to degrade CS-GAGs at the injury site, up- regulate GAP-43 in injured neurons, and promote regeneration of both ascending sensory projections and descending corticospinal tract axons. Postsynaptic activity below the lesion was restored and significant recovery of locomotor and proprioceptive behaviors ensued. In an interesting set of experiments, researchers used a PVC polymer tube filled with SCs to reattach the two stumps of a completely transected spinal cord. However, they also noticed that very few corticospinal axons had grown into the graft; that virtually no axons had grown out of the graft; and that noticeable tissue loss occurred at the graft–cord interfaces on both sides. Treating with MP prevented scaring and tissue loss at the interfaces and caused limited growth of axons back into the CNS environment. Treatment with BDNF and NT-3 caused brainstem nuclei to extend axons into the graft and increased the total number of axons in the graft. For example, optic nerve axons have been shown to grow through an SC graft and extend into the superior colliculus where they can form synapses. Axons are simply not easily persuaded to leave whatever growth- promoting environment that might be presented to them to enter the relatively inhospitable environment of the CNS. One study with embryonal spinal cord implants showed that when neurotro- phins were delivered with the implants, some host axons grew all the way through the implants. Furthermore, host axons formed synapses with the implanted cells and axons from the grafts extended for some distance into the host spinal cords. Recent advances in the understanding of the olfactory system have led to what might be the most promising approach to overcoming CNS growth inhibition. Neurons in the olfactory mucosa are constantly dying and are replaced by new neurons that must extend their axons into the CNS. A special group of cells known as olfactory ensheathing glia (OEG) form sheaths around these axons, express growth-promoting phenotypes, and accompany these growing axons into the CNS. One study showed significant recovery of function even when transplantation was delayed for 7 days following injury. Based on positive research findings, OEGs hold great promise for the future surgical treatment of human SCI. They found that when sufficient macrophages were transplanted, partial recovery of both functional and electrophysiological activities occurred. For example, the problem remains of ensuring that correct synaptic patterns are reestablished after regeneration takes place.

Kung fu means “skill” in Chinese buy 80 mg super levitra with visa erectile dysfunction which doctor to consult, and is the generic Many martial arts combine internal and external methods buy cheap super levitra 80mg on line erectile dysfunction medicine. On the meridians there are certain Kung fu consists of thousands of hard and soft tech- points (acupoints) where qi accumulates. Yin and yang are the two separate but com- to invent a martial art that emphasized non-aggression. GALE ENCYCLOPEDIA OF ALTERNATIVE MEDICINE 2 1295 In Japanese, aikido means “connecting with life energy. Aikido Some schools allow students to attend as many classes also teaches internal methods of cultivating qi energy. Two to three classes per week are recom- teaches the philosophical ideals of love and harmony as mended. Some schools charge a flat fee for Judo means “gentle way” in Japanese and was de- training from beginner to expert. Many schools require veloped as an educational tool by a teacher named Jigoro students to regularly participate in competitions, and fees Kano in the 1800s. Students are required to pur- moves as holds and grappling, and teaches students how chase uniforms and equipment as well. Uniforms may to disarm attackers by applying pressure to specific sen- cost $100 or more, and protective equipment may cost sitive points on the body. Prospective martial arts students should search for These movements emphasize posture and the flow of the the style of martial arts that best meets their objectives. Although considered a martial art and Students should attend classes at various schools (dojos), consisting of fighting postures, tai chi is used more as a and should talk to students and teachers to find the right meditation and health technique. Finding a good instructor may be even more people, particularly the elderly, use tai chi daily to im- important than finding the right school. Kendo is traditional Japanese sword fighting, quired to take blows and falls as part of the learning teaching students how to use various weapons with agili- process, as well as to fight with weapons. Kendo also emphasizes dis- should search for teachers and schools who teach these cipline and ethics. People with health condi- tions and injuries should consult a physician before at- tempting a martial art, and should find a teacher familiar A martial arts session with their condition. Then, depending on the school, certain exercises will be performed to improve strength, Martial arts teachers are usually certified with the speed, and stamina. Sparring is often used, with students achievement of an advanced black belt status. Some schools require students large schools of martial arts have organizations which to stop short of striking one another, while other schools oversee and certify the granting of belt ranks. The Aikido require students to wear equipment to protect them from Association of America recognizes training programs authentic blows. The USA Karate Federation is the largest organiza- Most martial arts use the colored belt system to rank tion for certifying ranking systems and schools of karate. In general, white belts signify beginners, kung fu schools, ranking systems, and contests. Yin/Yang—Universal characteristics used to de- The roots of modern, scientific massage therapy go scribe aspects of the natural world. Ling established the Royal Central Gymnastic Institute in Sweden in 1813 to teach Resources his methods. Berkeley, physicians, brothers George and Charles Taylor, who had CA: North Atlantic, 1998. New in the United States were opened by two Swedish physi- York: Thames and Hudson, 1981. Hartwig Nissen opened the Swedish Health Institute near the Capitol in Washington, D. Frey, PhD • reduction of muscle tension and stiffness • relief of muscle spasms • greater flexibility and range of motion • increase of the ease and efficiency of movement Massage therapy • relief of stress and aide of relaxation Definition • promotion of deeper and easier breathing Massage therapy is the scientific manipulation of • improvement of the circulation of blood and movement the soft tissues of the body for the purpose of normaliz- of lymph ing those tissues and consists of manual techniques that include applying fixed or movable pressure, holding, • relief of tension-related conditions, such as headaches and/or causing movement of or to the body. In beating percus- sion, use a loose fist to gently beat the fleshy areas of the body.

Once a hormone binds to a receptor on or in a target Anterior cell 80 mg super levitra visa erectile dysfunction medication names, it affects cell activities generic 80 mg super levitra with visa impotence injections medications, regulating pituitary the manufacture of proteins, changing the permeability of the membrane, or affecting metabolic reactions. Hormone Chemistry Thyroid Stimulates gland Chemically, hormones fall into two main categories: High level of thyroid Inhibits hormones inhibits ◗ Amino acid compounds. The anterior pitu- All hormones except those of the ad- itary releases thyroid stimulating hormone (TSH) when the blood level of thyroid hor- renal cortex and the sex glands fall mones is low. This is a typical example of the kind of self- also includes information on the effects of hypersecretion regulating system that keeps hormone levels within a set (oversecretion) or hyposecretion (undersecretion) of a normal range. That is, they produce substances that act on other Chapter 1, and the release of some hormones in the men- tissues, usually at some distance from where they are strual cycle, as described in Chapter 23. Hormones The pituitary is often called the master gland because The remainder of this chapter deals with hormones and it releases hormones that affect the working of other the tissues that produce them. By this circulatory “detour,” Ovaries some of the blood that leaves the hy- Testes pothalamus travels to capillaries in the anterior pituitary before returning to the heart. For example, the 248 ✦ CHAPTER TWELVE Table 12•1 The Endocrine Glands and Their Hormones GLAND HORMONE PRINCIPAL FUNCTIONS Anterior pituitary GH (growth hormone) Promotes growth of all body tissues TSH (thyroid-stimulating hormone) Stimulates thyroid gland to produce thyroid hormones ACTH (adrenocorticotropic hormone) Stimulates adrenal cortex to produce cortical hor- mones; aids in protecting body in stress situations (injury, pain) PRL (prolactin) Stimulates secretion of milk by mammary glands FSH (follicle-stimulating hormone) Stimulates growth and hormone activity of ovarian follicles; stimulates growth of testes; promotes development of sperm cells LH (luteinizing hormone); ICSH (interstitial Causes development of corpus luteum at site of cell-stimulating hormone) in males ruptured ovarian follicle in female; stimulates secretion of testosterone in male Posterior pituitary ADH (antidiuretic hormone) Promotes reabsorption of water in kidney tubules; at high concentration stimulates constriction of blood vessels Oxytocin Causes contraction of uterine muscle; causes ejection of milk from mammary glands Thyroid Thyroxine (T4) and triiodothyronine(T3) Increases metabolic rate, influencing both physical and mental activities; required for normal growth Calcitonin Decreases calcium level in blood Parathyroids Parathyroid hormone (PTH) Regulates exchange of calcium between blood and bones; increases calcium level in blood Adrenal medulla Epinephrine and norephinephrine Increases blood pressure and heart rate; activates cells influenced by sympathetic nervous system plus many not affected by sympathetic nerves Adrenal cortex Cortisol (95% of glucocorticoids) Aids in metabolism of carbohydrates, proteins, and fats; active during stress Aldosterone (95% of mineralocorticoids) Aids in regulating electrolytes and water balance Sex hormones May influence secondary sexual characteristics Pancreatic islets Insulin Needed for transport of glucose into cells; required for cellular metabolism of foods, especially glucose; decreases blood sugar levels Glucagon Stimulates liver to release glucose, thereby increasing blood sugar levels Testes Testosterone Stimulates growth and development of sexual organs (testes, penis) plus development of secondary sexual characteristics, such as hair growth on body and face and deepening of voice; stimulates maturation of sperm cells Ovaries Estrogens (e. In- uretic hormone, or ADH, and oxytocin) are actually pro- hibiting hormones suppress both growth hormone, duced in the hypothalamus and stored in the posterior pi- which stimulates growth and metabolism, and prolactin, tuitary. THE ENDOCRINE SYSTEM: GLANDS AND HORMONES ✦ 249 Table 12•2 Disorders Associated with Endocrine Dysfunction HORMONE EFFECTS OF HYPERSECRETION EFFECTS OF HYPOSECRETION Growth hormone Gigantism (children), acromegaly (adults) Dwarfism (children) Antidiuretic hormone Syndrome of inappropriate antidiuretic Diabetes insipidus hormone (SIADH) Aldosterone Aldosteronism Addison disease Cortisol Cushing syndrome Addison disease Thyroid hormone Graves disease, thyrotoxicosis Infantile hypothyroidism (cretinism) in chil- dren; myxedema in adults Insulin Hypoglycemia Diabetes mellitus Parathyroid hormone Bone degeneration Tetany (muscle spasms) Internal-external stimuli Neurotransmitters Hypothalamus 12 Releasing hormones secreted ADH Oxytocin Infundibulum Portal system Posterior pituitary Hormones feed back to anterior pituitary Anterior pituitary and hypothalamus Breast Oxytocin Thyroid TSH ADH Uterus Thyroid hormones ACTH Adrenal Kidney PRL FSH Ovary FSH GH Adrenocorticosteroids LH LH (ICSH) Estrogen Corpus Breast luteum Testes Bone and Progesterone soft tissues Testosterone Figure 12-3 The hypothalamus, pituitary gland, and target tissues. This ◗ Growth hormone (GH), or somatotropin (so-mah-to- type of diabetes should not be confused with diabetes TRO-pin), acts directly on most body tissues, promot- mellitus, which is due to inadequate amounts of in- ing protein manufacture that is essential for growth. Tumors of the Pituitary The effects of pituitary tu- ◗ Follicle-stimulating hormone (FSH) stimulates the devel- mors depend on the cell types in the excess tissue. A person who develops ovulation in females and sex hormone secretion in both such a tumor in childhood will grow to an abnormally tall males and females; in males, the hormone is sometimes stature, a condition called gigantism (ji-GAN-tizm) (see called interstitial cell–stimulating hormone (ICSH). FSH and LH are classified as gonadotropins (gon-ah- If the GH-producing cells become overactive in the do-TRO-pinz), hormones that act on the gonads to regu- adult, a disorder known as acromegaly (ak-ro-MEG-ah- late growth, development, and function of the reproduc- le) develops. The fingers resemble a spatula, and the face takes on a coarse appearance: the nose widens, the Hormones of the Posterior Lobe lower jaw protrudes, and the forehead bones may bulge. In hu- itary tries to compensate for decreased glucocorticoid levels mans, though, MSH levels are usually so low that its role as a by increasing POMC production. This is so because pituitary regulating pigmentation, women do produce more MSH dur- cells do not produce ACTH directly but produce a large pre- ing pregnancy and often have darker skin. Calcitonin works with parathyroid hor- exhibit signs of underactivity of other endocrine glands mone and with vitamin D to regulate calcium metabo- that are controlled by the pituitary, such as the ovaries, lism, as described below. Disorders of the Thyroid Gland A goiter (GOY- Evidence of tumor formation in the pituitary gland ter) is an enlargement of the thyroid gland, which may may be obtained by radiographic examinations of the or may not be associated with overproduction of hor- skull. Computed tomography (CT) and magnetic res- adenomatous (ad-eh-NO-mah-tus), or nodular, goiter onance imaging (MRI) scans are also used to diagnose pi- is an irregular-appearing goiter accompanied by tumor tuitary abnormalities. Underactivity of the thy- roid, known as hypothyroidism (hi-po-THI-royd-izm), The thyroid, located in the neck, is the largest of the en- shows up as two characteristic states related to age: docrine glands (Fig. The thyroid has two roughly oval lateral lobes on either side of the larynx (voice box) ◗ Infantile hypothyroidism, also known as cretinism connected by a narrow band called an isthmus (IS-mus). Iodine deficiency is rare now myxedema regains health easily, although treatment due to widespread availability of this mineral in iodized must be maintained throughout life. Hyperthyroidism is the opposite of hypothyroidism, Another hormone produced by the thyroid gland is that is, overactivity of the thyroid gland with excessive se- calcitonin (kal-sih-TO-nin), which is active in calcium cretion of hormone. A common form of hyperthyroidism is Graves disease, which is characterized by a goiter, a strained appearance of the face, intense nervousness, Epiglottis weight loss, a rapid pulse, sweating, tremors, and an ab- normally quick metabolism. Another characteristic symp- Thyroid gland Hyoid bone (right lobe) tom is protrusion (bulging) of the eyes, known as exoph- thalmos (ek-sof-THAL-mos), which is caused by swelling of the tissue behind the eyes (Fig. Treatment of Isthmus of Larynx thyroid gland hyperthyroidism may take the following forms: ◗ Suppression of hormone production with medication Trachea ◗ Destruction of thyroid tissue with radioactive iodine ◗ Surgical removal of part of the thyroid gland Figure 12-4 Thyroid gland (anterior view). The two lobes An exaggerated form of hyperthyroidism with a sud- and isthmus of the thyroid are shown in relation to other struc- den onset is called a thyroid storm. The secretion of these glands, parathyroid hormone (PTH), promotes calcium release from bone tissue, thus increasing the amount of calcium circulating in the bloodstream. The four and measuring the amount and distribution of radiation small parathyroid glands are embedded in the posterior surface that accumulates in the thyroid gland.

Bizzi and colleagues57–60 have shown discount super levitra 80mg erectile dysfunction treatment himalaya, in experiments in the frog and rat purchase super levitra 80 mg otc erectile dysfunction symptoms age, that a set of “motor primitives,” which could form the basis of activating specific sets of muscles during multiple joint movement, can be elicited through microsimulation of the spinal gray matter. These primitives may form the building blocks for voluntary movement by translating spatial signals from the motor cortex into appropriate muscle output. Recent data from experiments using long trains of intracortical microstimulation suggest that the motor cortex may be able to access such primitives directly. These propriospinal interneurons may participate in the integration of reaching movements at a spinal level, and may effectively translate signals from cells in the motor cortex that relate to the direction of force output of the whole limb55 into appropriate patterns of muscle activation. It is likely that the association between motor cortex cell activity and motor primitive “modules” at another level in the motor system is established through learning and adaptation. Though conceptually attractive, the idea of successive coordinate transforma- tions in frontal motor areas culminating in a muscle or joint based coding of motor output in motor cortex63 does not have strong experimental support and should be abandoned, at least as applied to skilled movements. The search for a direct reflection of the motor periphery in the motor cortex is likely to be as futile as the quest for the representation of the single muscle. The well- defined goal, moving the hand to a spatial location, makes it a popular paradigm for exploring sensorimotor function. This conversion of sensory to motor signals involves many cortical and subcortical regions of the CNS, and a major focus of research is to identify the role played by each of these regions. While cells are unlikely literally to code any engineering- inspired variable, it is nonetheless valuable (and even necessary) to relate neural activity to some features of behavior reflecting sensory, cognitive, or motor aspects of the task. How one chooses which variable to correlate depends highly on the conceptual framework used to develop the experiment. This chapter starts with the important issue of how theoretical concepts guide experimental design and data analysis. I will describe two conceptual frameworks for interpreting neural activity during reaching: sensorimotor transformations and inter- nal models. Both frameworks address the same biological problem: How does the brain control the limb to reach toward a spatial target? The key difference is that each framework focuses attention on a different aspect of the motor task and thus each leads to different experiments. The sensorimotor transformations framework has been used extensively over the past 20 years to guide neurophysiological exper- iments on reaching, whereas the internal models framework has only recently had an impact on experimental design. The second half of this chapter illustrates how the notion of internal models can be used to explore the neural basis of movement. A new experimental facility is described that can sense and perturb multiple-joint planar movements and this is followed by a brief description of the mechanics of limb movement. Finally some preliminary observations are presented on neural correlates in the primary motor cortex (M1) of the mechanical properties of the limb and of external mechanical loads. The use of intermediary repre- sentations to plan and control movement seems like a reasonable assumption, par- ticularly given the ubiquitous observation that hand trajectories are relatively straight for point-to-point reaching movements. As described below, some experiments Copyright © 2005 CRC Press LLC A Target Hand Joint Joint Muscle Location Kinematics Kinematics Torques Activity B Muscle + Activity Desired State Internal Model + Musculoskeletal Limb Movement (Limb Position) of Musculoskeletal System - System - Central Sensory Feedback: Nervous System (Vision, Proprioception) FIGURE 6. This framework leads to the scientific problem of identifying how these representations are reflected in the discharge pattern of neurons in different brain regions. This framework leads to the scientific problem of identifying how information related to the motor periphery and physical loads is reflected in the discharge pattern of neurons. In other cases, a specific class of variable has been chosen a priori, either based on the results of previous studies or simply for technical reasons. One of the first studies to record neural activity in the motor cortex during reaching found that cell discharge was broadly tuned to the direction of hand motion. Further, the direction of hand motion could be predicted from the discharge pattern of an ensemble of neurons; this was termed the population vector hypothesis. A recent theoretical study by Todorov13 reiterated this point by illustrating how a broad range of observations between hand movement and neural activity, both at the single-cell and at the population level, could be explained if cells were simply coding multidimensional muscle activation patterns. While the correct explanation of the precise details of all hand-based correlations is a matter of debate,14–17 the article by Todorov illustrates how difficult it is to interpret the discharge of neurons with simple correlation methods.