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By W. Tom. Air University. 2018.

The technique of free-basing basing or smoking crack can lead to pul- cocaine buy super viagra 160mg mastercard, which gained popularity in the monary complications buy super viagra 160 mg low cost. Chronic use of 1980s discount 160mg super viagra mastercard, involves heating a flammable sol- intranasal cocaine may cause ulceration or vent such as petroleum or ether buy super viagra 160mg visa, and then perforation of the nasal septum super viagra 160mg for sale. The process intoxication can produce neurologic effects, “frees” cocaine hydrochloride from its such as confusion, anxiety, hyperexcitabil- salts and adulterants, converting it to a ity, agitation, and violence. The effects are the result of acute cocaine toxi- free-base cocaine can be inhaled or city, which is dose related, in which indi- smoked, usually with a water pipe, for viduals can experience stroke or seizures, direct absorption through the alveoli in severe hyperthermia (increased body the lungs. The technique rapidly delivers temperature), arrhythmia (irregular heart- high concentrations of cocaine to the beat), myocardial infarction (heart brain and results in blood levels as high attack), and, in some instances, sudden as those for self-injection. Cocaine psychosis, another side The free-basing technique can cause effect of cocaine use, is manifested by additional disability caused by the burns paranoia, panic, hallucinations, insomnia, from fires started during the free-basing and picking at the skin. The level of tolerance for cocaine episode can last from 24 to 36 hours. Dependence is produced profit on its sale, may cause additional very rapidly. Its concentrated form and its route result from the nature of the substance of administration make its potency many used to cut the cocaine or from the dosage times greater than that of cocaine alone. Adulterants such as talc or corn- The euphoric effect produced by crack starch can cause complications ranging Use Disorders Involving Other Substances 217 from inflammation to embolus (undis- psychoactive responses to the drug depend solved matter in the blood). Often, users report a sense of time tain of cocaine’s potency, the effects are slowing and an impairment in their abil- not always predictable. The withdrawal ity to learn new facts while they are under syndrome from cocaine consists of a crav- the influence of the drug. Because it is not unusu- an increase in heart rate, dilation of the al for individuals who are cocaine depend- bronchioles, and dilation of the peripher- ent to also be dependent on other drugs, al blood vessels. Because of the stimulato- a withdrawal reaction from other sub- ry effect on the heart, cannabis use may stances may be experienced as well. Chronic smoking amphetamine is crystalline methampheta- of cannabis produces inflammatory mine (“ice”), which is highly addictive changes in the lungs that contribute to the physically and psychologically (Lukas, development of chronic conditions such 1997). The technique is similar to that more, the use of other drugs, including of smoking free-base cocaine. Ice has alcohol and tobacco, may compound greater strength and more enduring the adverse effects of cannabis. Greater ple, the combination of tobacco and stimulation to the brain makes it more cannabis use is thought to increase the risk dangerous mentally because it creates a of lung cancer. Toxic lev- orally, oral consumption can delay its els can produce severe paranoid thinking effects for up to an hour, and the effects with hallucinations. Chronic use of form of THC, is also smoked and has con- methamphetamine in any form can result siderably more potency than does cannabis. The degree to which can- When cannabis (marijuana) is smoked, nabis creates physical dependence has not the active compound (THC) that it con- been established; however, it may be pos- tains produces euphoria, relaxation, dream- sible to develop psychological dependence like states, and sleepiness. Individuals may report height- severely hampers individuals’ functioning, ened sensitivity and clarity, increased treatment most often involves psycho- insights, a sense of time moving more therapeutic techniques directed at under- slowly, and distortions of visual images. Because cannabis may be Some individuals experience adverse abused in combination with other drugs, effects from LSD, such as a panic state treatment may occasionally be multifocal with severe anxiety. The physical consequences of hallucino- gen abuse in and of themselves are not sig- Hallucinogens nificant. Adverse effects of Sometimes called psychedelics, hallu- hallucinogens vary from acute psychosis to cinogens are drugs that, at some dosage, self-mutilation or suicide. Accidents can produce hallucinations or distortions in per- result from misjudgment or impairment. Individuals under the Some individuals experience “flashbacks” influence of hallucinogens report in- in which hallucinations reappear briefly creased awareness of sensory input and a even months after the last drug dose. An subjective feeling of enhanced mental overdose of hallucinogens can result in activity. Common hallucinogens are LSD, exceedingly high body temperatures, PCP (angel dust), and mescaline. Controlled substance analogues, or Because hallucinogens produce no designer drugs, can have dangerous, perma- physical dependence, there is no specific nent effects.

Regardless of the bio- ing to this theory discount super viagra 160mg without prescription, when one hormone molecule binds to its logical pathway or process being considered discount super viagra 160mg online, cells typically receptor discount 160 mg super viagra overnight delivery, it causes a decrease in the affinity of nearby un- exhibit an intrinsic basal level of activity in the absence of occupied receptors purchase 160mg super viagra free shipping, making it more difficult for additional added hormone discount 160mg super viagra free shipping, even well after any previous exposure to hormone molecules to bind. As the hormone concentration surrounding the hormone bound, the lower the affinity of unoccupied re- cells increases, a minimal threshold concentration must be ceptors. At higher hormone concentra- tions, a maximal response by the target cell is produced, A and no greater response can be elicited by increasing the hormone concentration. The concentration of hormone re- quired to produce a response half-way between the maxi- mal and basal responses, the median effective dose or Slope = -K ED50, is a useful index of the sensitivity of the target cell a Bound hormone for that particular hormone (see Fig. For some peptide hormones, the maximal response may Free hormone occur when only a small percentage (5 to 10%) of the total X-intercept = receptor population is occupied by hormone. The remain- receptor ing 90 to 95% of the receptors are called spare receptors number (R0) Bound hormone Maximal response 100 B Bound hormone -Ka1 Free hormone -Ka 50 2 R0 R0 1 2 Bound hormone Threshold Basal FIGURE 31. A, A straight-line plot typical of hor- mone binding to a single class of receptors. B, A curvilinear Log hormone concentration Scatchard plot typical of some hormones. Several models have been proposed to account for nonlinearity of Scatchard plots. CHAPTER 31 Endocrine Control Mechanisms 579 because on initial inspection they do not appear necessary A B to produce a maximal response. This term is unfortunate, because the receptors are not “spare” in the sense of being unused. While at any one point in time only 5 to 10% of the receptors may be occupied, hormone-receptor interactions are an equilibrium process, and hormones continually dis- sociate and reassociate with their receptors. Therefore, from one point in time to the next, different subsets of the total population of receptors may be occupied, but presum- ably all receptors participate equally in producing the bio- logical response. Physiological or pathophysiological alterations in target Log hormone concentration Log hormone concentration tissue responses to hormones can take one of two general Altered target tissue responses reflected by FIGURE 31. A change in responsiveness is indicated by an ber of receptors for that hormone per cell. This phenomenon increase or decrease in the maximal response of the target is referred to as down-regulation. In the case of peptide hor- tissue and may be the result of one or more factors (Fig. Altered responsiveness can be caused by a change of receptors from the cell surface to intracellular sites usually in the number of functional target cells in a tissue, by a occurs as part of the process of down-regulation. Therefore, change in the number of receptors per cell for the hormone there may be fewer total receptors per cell, and a smaller per- in question or, if receptor function itself is not rate-limiting centage may be available for hormone binding on the cell sur- for hormone action, by a change in the specific rate-limiting face. Although somewhat less prevalent than down-regula- postreceptor step in the hormone action pathway. Changes in rates of receptor synthesis may also con- a right shift indicates decreased sensitivity and a left shift tribute to long-term down- or up-regulation. Changes in sensitivity reflect (1) an alteration in cells can regulate receptor function. Chronic exposure of receptor affinity or, if submaximal concentrations of hor- cells to a hormone may cause the cells to become less re- mone are present, (2) a change in receptor number. Dose- sponsive to subsequent exposure to the hormone by a response curves may also reflect combinations of changes process termed desensitization. If the exposure of cells to in responsiveness and sensitivity in which there is both a a hormone has a desensitizing effect on further action by right or left shift of the curve (a sensitivity change) and a that same hormone, the effect is termed homologous de- change in maximal biological response to a lower or higher sensitization. If the exposure of cells to one hormone has level (a change in responsiveness). The principal mineralocorticoid in the globulin (CBG) completions of the statement. The ability of hormones to be effective ONE lettered answer or completion that is Aldosterone regulators of biological function BEST in each case. A shift to the right in the biological (D) Cortisol Transport proteins activity dose-response curve for a 4.

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US demonstrates a hypoe- is diagnosed when the tendon cannot be appreciated at choic area of tendinosis (arrows) at the common extensor insertion buy discount super viagra 160mg on-line, the level of the injury and the swollen end is detected in which a partial tear (asterisk) is noted proximally discount 160 mg super viagra free shipping. Microtraumatic tendon diseases cheap super viagra 160 mg mastercard, including De Quervain disease and trigger finger generic super viagra 160mg on-line, are due to repetitive movements that induce friction at the level of the osteofibrous tunnel (Fig cheap super viagra 160 mg free shipping. US can easily detect partial tears, calcifications, or synovitis [27, 28]. Com- tendon swelling, echo texture changes, and synovial plete tendon disruption represents a FTT. Cortical irreg- sheath effusion, and eventually guide a local steroid in- ularity or spur formation can be detected at the epi- jection. Intratendinous neo-angiogenesis or peri- tendinous hyperemia can be demonstrated using power Doppler evaluation. Typical signs of a distal biceps tendon rupture are: a retracted distal biceps tendon causing acoustic shadow- ing, and a triangular-shaped blood-filled cavity at the musculotendinous junction. Ultrasound can also demonstrate non-retracted tears and PTT with abnormal undulation of tendon fibers. A thickened heteroge- neous tendon is present in tendinosis; a fluid-filled bicip- ito-radial bursa can also be demonstrated. The ulnar nerve measures 2-3 mm and should be eval- uated comparatively and dynamically during flexing of the elbow. In cubital tunnel syndrome, the ulnar nerve is thickened, hypoechoic and can be subluxed. US can reveal underlying masses, large joint effusions, synovial proliferations, bony protuberances, and an an- coneus epitrochlearis muscle. Sonogram of the dorsal aspect of the wrist wall thickening, hypoechoic fluid and echogenic fibrous shows a hyperechoic foreign body (white arrowhead) surrounded by a hypoechoic inflammatory halo (empty arrowheads). Surgical clots), gout (hyperechoic nodular crystal depositions± exploration revealed a wood splinter acoustic shadowing), or infection (intermediate echogenic fluid, surrounding edema, positive power Doppler, for- eign body). Hand and Wrist Small-size US probes, utilizing frequencies ranging from 10 to 17 MHz, allow accurate assessment the superficial tissues of the hand and wrist. The combination of standard radiographs with US works well in the evalua- Fig. Longitudinal sonogram of tion of a large spectrum of disorders, although several the first extensor compartment of the wrist. Longitudinal (a) and conditions cannot be diagnosed by US and require MR or transverse (b) images show the thickened, hypoechoic retinaculum MR-arthrography for proper evaluation. Marcelis Arthritis and Tenosynovitis Soft-Tissue Tumors US allows diagnosis and follow-up of inflammatory dis- As discussed above, the most common masses of the orders affecting the hand and wrist. At early stages, hand and wrist are ganglia and giant-cell tumor of when osseous erosions are not detected by standard ra- the tendon sheath. Ganglia are depicted as well-demar- diographs, it demonstrates paraarticular edema as well cated, anechoic masses with regular borders without in- as joint- and tendon-sheath effusions. In older le- the synovial membrane (pannus) producing marginal sions, internal septa and fibrosis explain the hypoechoic erosions can also be detected (Fig. US-guided aspiration and local steroid in- can be differentiated from active vascular hypertrophy jection can be performed in selected cases. US aids in guiding a diagnostic tumors of the tendon sheath appear on US as paraartic- joint puncture and allows proper intraarticular injection ular or paratendinous, solid, hypoechoic well-marginat- of steroids. They may also cause pressure erosions on the Entrapment Neuropathies cortical bone of the phalanges. Although the US find- ings are not specific, US is invaluable in accurate eval- Entrapment neuropathies of the wrist concern the medi- uation of tumor size, location and relationship to sur- an nerve at the carpal tunnel and the ulnar nerve at rounding structures, as well as in the early diagnosis of the Guyon tunnel. The cause of the compression (tenosynovitis, ganglia, amyloid deposits) can also be de- Hip Sonography tected by US. In carpal tunnel syndrome, US allows: (1) confirmation of the diagnosis when invasive nerve con- Ultrasound detects different types of joint effusions in the duction studies are not accepted by the patient, (2) aid in hip when an anterior approach is used. The effusion can planning surgery by demonstration of anatomic variants, be demonstrated between the hyperechoic linings of the such as a bifid median nerve or the presence of median iliofemoral ligament and the femoral neck (transient syn- artery, and by detection of expansible masses that cannot ovitis, septic arthritis, rheumatoid arthritis, osteoarthritis, be successfully treated by endoscopy. Longitudinal (a) and trans- verse (b) US images obtain- ed over the pal- Fig. Longitudinal (a) and transverse mar aspect of (b) color Doppler images obtained over the dorsal aspect of the the third finger.

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Psychiatric Disorders Involve the Limbic System Current research is focused on finding the subtype of The major psychiatric disorders buy super viagra 160mg amex, including affective disor- dopamine receptor that mediates mesocortical/mesolimbic ders and schizophrenia generic super viagra 160 mg mastercard, are disabling diseases with a ge- dopaminergic transmission but does not affect the nigrostri- netic predisposition and no known cure buy 160 mg super viagra with visa. So basis for these disorders remains obscure 160 mg super viagra free shipping, particularly the far generic 160mg super viagra, neuroleptic drugs that block one pathway almost always role of environmental influences on individuals with a ge- block the other as well, leading to unwanted neurological netic predisposition to developing a disorder. Altered side effects, including abnormal involuntary movements (tar- states of the brain’s monoaminergic systems have been a dive dyskinesia) after long-term treatment or parkinsonism major focus as possible underlying factors, based on ex- in the short term. Similarly, some patients with Parkinson’s tensive human studies in which neurochemical imbalances disease who receive L-DOPA to augment dopaminergic in catecholamines, acetylcholine, and serotonin have been transmission in the nigrostriatal pathway must be taken off observed. Another reason for focusing on the monoamin- the medication because they develop psychosis. The affective disorders include ma- Memory and learning are inextricably linked because part jor depression, which can be so profound as to provoke sui- of the learning process involves the assimilation of new in- cide, and bipolar disorder (or manic-depressive disorder), formation and its commitment to memory. The most likely in which periods of profound depression are followed by sites of learning in the human brain are the large association periods of mania, in a cyclic pattern. Biochemical studies areas of the cerebral cortex, in coordination with subcorti- indicate that depressed patients show decreased use of cal structures deep in the temporal lobe, including the hip- brain NE. The association areas draw on Whether in depression or in mania, all patients seem to sensory information received from the primary visual, audi- have decreased brain serotonergic transmission, suggesting tory, somatic sensory, and olfactory cortices and on emo- that serotonin may exert an underlying permissive role in tional feelings transmitted via the limbic system. This in- abnormal mood swings, in contrast with norepinephrine, formation is integrated with previously learned skills and whose transmission, in a sense, titrates the mood from stored memory, which presumably also reside in the asso- highest to lowest extremes. The most effective treatments for depression, including The learning process itself is poorly understood, but it antidepressant drugs such as MAOIs and selective serotonin can be studied experimentally at the synaptic level in iso- CHAPTER 7 Integrative Functions of the Nervous System 131 lated slices of mammalian brain or in more simple inver- An early demonstration of the dichotomy between de- tebrate nervous systems. Synapses subjected to repeated clarative and procedural memory came from studies by Dr. An early event in long-term potentiation is ber ever having done the task before. Declarative memory can be di- a host of intracellular proteins and altered excitability. In vided into that which can be recalled for only a brief period addition to biochemical changes in synaptic efficacy as- (seconds to minutes), and that which can be recalled for sociated with learning at the cellular level, structural al- weeks to years. The number of connections between sets readily recalled for only a few minutes or more using short- of neurons increases as a result of experience. An example of short-term memory is look- Much of our knowledge about human memory forma- ing up a telephone number, repeating it mentally until you tion and retrieval is based on studies of patients in whom finish dialing the number, then promptly forgetting it as stroke, brain injury, or surgery resulted in memory dis- you focus your attention on starting the conversation. Such knowledge is then examined in more rigor- Short-term memory is a product of working memory; the ous experiments in nonhuman primates capable of cog- decision to process information further for permanent stor- nitive functions. From these combined approaches, we age is based on judgment as to its importance or on whether know that the prefrontal cortex is essential for coordi- it is associated with a significant event or emotional state. The conversion of short-term to input from the parietal, occipital, and temporal lobes long-term memory is facilitated by repetition, by adding and emotional input from the limbic system. Drawing on more than one sensory modality to learn the new experience skills such as language and mathematical ability, the pre- (e. The prefrontal cortex can thus experience (through the limbic system) to a strong, mean- be considered the site of working memory, where new ingful emotional context. The role of the hippocampus in experiences are processed, as opposed to sites that con- consolidating the memory is reinforced by its participation solidate the memory and store it. The processed infor- in generating the emotional state with which the new expe- mation is then transmitted to the hippocampus, where it rience is associated. As determined by studying patients is consolidated over several hours into a more permanent such as H. Once a long-term memory is formed, the hippocampus Declarative and Procedural Memory. Nor was there loss of intellectual ca- Declarative memory refers to memory of events and facts pacity, mathematical skills, or other cognitive functions. Mil- bilateral medial temporal lobectomies lose their ability to ner, who worked with him for years, had to introduce her- form any new declarative memories. However, they retain self to her patient every time they met, even though he their ability to learn and remember new skills and proce- could readily remember people and events that had oc- dures. This type of memory is called procedural memory curred before his surgery. The primacy of the hip- tive memory, structures in the medial temporal lobe are pocampus and its connections with the base of the fore- not involved in procedural memory.

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