Genomic Searches

In most cases, no a priori information is available on the nature or location of the gene in question. A random search of the genome for QTL is then the most viable strategy employed. A first strategy is sib pair analysis. As in classical pedigree studies, several hundred DNA markers are obtained from siblings and (optimally) their parents. Siblings in a sib pair study, however, come from different families rather than from a few single pedigrees. By definition, the differences between two...

Trichloroethylene

Trichloroethylene (TCE) is commonly used as a degreasing solvent in industrial settings. The neuro-toxic effects of TCE are associated with exposure to the parent molecule and to its environmental degradation product, dichloroacetylene (DCA). Because DCA is derived from TCE, individuals working with TCE or encountering it in nonoccupational settings are at risk for the neurotoxic effects of both chemicals. Acute exposure to TCE induces narcosis characterized by subtle behavioral changes and...

L Toxic Encephalopathy

Although a wide spectrum of substances have toxic effects that can ultimately result in cerebral edema, a direct causal relationship has been established for only a few toxins of clinical significance. Children and adolescents appear to be particularly vulnerable to these toxic exposures. Adolescents ingesting large doses of vitamin A may develop pseudotumor cerebri and visual loss. Organic tin compounds used for the treatment of furunculosis and the use of hexachlor-ophene as a disinfectant...

M Vomiting

The act of vomiting involves patterned contraction of striated muscles of the abdominal wall, pharynx, larynx, tongue, and face, together with a reversal of normal smooth muscle action in the upper intestine and stomach and a relaxation of the esophageal sphincter. This complex sequence of events can be initiated either in the gastrointestinal tract or in the brain. Axons of the vagus nerve innervate the upper gastrointestinal tract. Serotonin, released by emetic agents from small cells in the...

Neurologic Rehabilitation

Clinical rehabilitation has developed in an ad hoc fashion. The first formal stroke rehabilitation method, published by Frenkel in the mid- 19th century, emerged from a program that a nonprofessional wife had developed to successfully rehabilitate her husband. Rehabilitation clinicians still rely on nontheory-related methodologies. Little has been written about the fact that rehabilitation as currently practiced has such meager carryover to real-life activities, and even little carryover from...

Management And Treatment A Presenting the Diagnosis

The way in which a diagnosis of conversion or somatoform illness is presented can have a considerable effect on the doctor-patient relationship it may also be an important factor in whether the patient cooperates with the management plan. Coming to terms with a diagnosis of conversion or somatization is difficult for many patients, who often believe that their suffering is being dismissed as all in the mind'' or, worse, deliberately faked. Understandably, many patients find it difficult to...

The Nucleus of the Solitary Tract

The nucleus of the solitary tract consists of medial and lateral divisions, which are innervated in a highly selective manner by the terminals of the vagal sensory neurons this provides the basis for a central sensory viscerotopy. The solitary nucleus is a complex integration center subserving many functions and also receives information from the parvocellular vasopres-sin containing neurons in the hypothalamus increased levels of vasopressin are associated with nausea. Further, the amygdala...

The Preferred Treatment of Nausea and Vomiting Is Removal of the Cause

Persistent nausea or vomiting may be indicative of gastrointestinal, neurologic, or metabolic disorders that require direct treatment, and it may be desirable to withhold antiemetic therapy until a diagnosis has been made. However, it remains clear that the treatment ofa cardiovascular pathology such as migraine with su-matriptan will relieve the neurologic manifestations, headache, gastrointestinal effects, nausea, and vomiting. Yet sumatriptan has no direct effect on the emetic reflex....

Lead

The acute symptoms of exposure to lead include abdominal colic, constipation, anorexia, vomiting, headaches, lightheadedness, dizziness, forgetfulness, anxiety, depression, irritability, excessive sweating, and muscle and joint pain. Acute symptoms subside following cessation of exposure and the reduction of blood lead levels. Chronic lead exposure results in more persistent neurological manifestations, including peripheral neuropathy and encephalopathy. Encepha-lopathy is the most serious...

Pathophysiology

The concept of cerebral edema has been recognized for more than 2000 years, yet an understanding of the complex physiology of this condition has evolved only within the past 30 years. Ancient Greek authors used the term oidzma to describe the swelling of the brain that resulted from compound skull fractures. Hippocrates noted that removal of the overlying skull bones allowed the injured brain to swell outward, thus minimizing compression of normal tissue trapped within the cranial vault. The...

Stimuli Arising from the Vestibular Labyrinth and Visual System

All animals that move must remain oriented to their surroundings, and for most movements this requires maintenance of balance and posture, measurement of the changes of bodily position, and the adjustment of eye position when the head is moving. This is also important for the maintenance of homeostasis upon a change of posture compensation must be rapid to maximize respiratory requirements and direct blood flow to the areas of need. However, unlike most sensations, orientation, movement...

The Expression Of Fear And Anxiety

Emotion is composed of several elements, including affective valence and arousal. Fear, like anger, is a protective emotion. It is a feeling of agitation and anxiety caused by the presence or imminence of danger and refers to a state or condition marked by this feeling. Fear has evolved as a vitally important physiological response to dangerous situations that prepares one to evade or confront a threat in the environment. Fear has played a critical role in survival, and therefore efficient fear...

Brain Stem Dysfunction In Disease

Squiggly Line Brain Stem Mri

Most people are used to the idea that dysfunction of one cerebral hemisphere can lead to paralysis of the other side of the body. This may occur, for example, with ischemia of brain tissue supplied by the internal carotid artery or the middle cerebral artery. Sudden impairment of the blood supply is also a common cause of brain stem dysfunction, but in this case it is the vertebrobasilar system of arteries that is at fault. Other disease processes infection, neoplasm, and inflammation may also...