Central nervous system definition

There is a definite trend of bidirectional cross-talk between opioid and chemokine receptors in the central nervous system. In vitro, as well as in vivo studies, have shown desensitization of CXCR4 by MOR and thus prevent the neuroprotective action of this chemokine. Although the precise molecular mechanism underlying this cross-talk is still under investigation, based on the evidences in literature several possible pathways can be expected to act independently or in concert and lead to the deficit of CXCR4 function. Our studies have shown that p opioids can increase the brain levels of FHC which can subsequently block CXCR4 signaling. Eurther studies... 

TABLE 67-3. Pathogen-Based Definitive Treatment for Central Nervous System Infections... 

The transport of information from sensors to the central nervous system and of instructions from the central nervous system to the various organs occurs through electric impulses transported by nerve cells (see Fig. 6.17). These cells consist of a body with star-like projections and a long fibrous tail called an axon. While in some molluscs the whole membrane is in contact with the intercellular liquid, in other animals it is covered with a multiple myeline layer which is interrupted in definite segments (nodes of Ranvier). The Na+,K+-ATPase located in the membrane maintains marked ionic concentration differences in the nerve cell and in the intercellular liquid. For example, the squid axon contains 0.05 MNa+, 0.4 mK+, 0.04-0.1 m Cl-, 0.27 m isethionate anion and 0.075 m aspartic acid anion, while the intercellular liquid contains 0.46 m Na+, 0.01 m K+ and 0.054 m Cl-. 

CDC Case Definition Laboratory criteria for diagnosis is (1) a positive direct fluorescent antibody test (preferably performed on central nervous system tissue) or (2) isolation of rabies virus (in cell culture or in a laboratory animal). 

CDC Case Definition Arboviral infections may be asymptomatic or may result in illnesses of variable severity sometimes associated with central nervous system (CNS) involvement. When the CNS is affected, clinical syndromes ranging from febrile headache to aseptic meningitis to encephalitis may occur, and these are usually indistinguishable from similar syndromes caused by other viruses. Arboviral meningitis is characterized by fever, headache, stiff neck, and pleocytosis. Arboviral encephalitis is characterized by fever, headache, and altered mental status ranging... 

Grossly elevated concentrations of dissolved copper produce teratogenicity in fish embryos. A significant number of malformed fish larvae came from eggs treated with 500 pg Cu/L (Birge and Black 1979). In studies with laboratory animals and elevated concentrations of copper salts, copper penetrates the placental barrier into the fetus intramuscular injection of 4 mg Cu/kg BW early in pregnancy adversely affects fetal central nervous system development (Aaseth and Norseth 1986). In humans, no definitive data are available on whether copper can cause birth defects however, incubation of human spermatozoa with metallic copper results in loss of sperm motility (Aaseth and Norseth 1986). 

The autonomic nervous system is by definition that part of the nervous system that innervates smooth muscle, cardiac muscle and glands. It is thus a motor system. Perception arising from the viscera involves pathways similar to those arising from the body surface and skeletal muscle. Thus there are visceral afferent fibres that pass from the viscera to the central nervous system. Such impulses then ascend the spinal cord to the thalamus and are thence relayed to the post-central gyrus of the brain (or sensory cortex). Visceral reflex arcs use visceral afferent fibres to convey impulses to the cord, but the efferent limb of such a visceral reflex is the autonomic nervous system. Although visceral reflexes are under higher central control, it is usually impossible to bring them under the control of the will. 

Reproductive Effects. It has not been definitively determined whether chloroform exposure induces reproductive effects in humans. No studies were located regarding reproductive effects in humans after inhalation or dermal exposure to chloroform. Only one study was located regarding reproductive effects in humans after oral exposure to chloroform. Bove et al. (1995) studied the effects of drinking-water consumption on birth outcomes and found that exposure to TTHM at levels >0.1 ppm resulted in reduced birth weight and size as well as an increased risk of oral cleft, central nervous system, and neural tube defects. These results should be viewed with caution since the authors did not specifically monitor chloroform levels. The effects seen may be due to exposure to other THMs or non-THM contaminants in the drinking water. 

Epilepsy is a chronic often progressive disorder of the central nervous system (CNS). Periodic and unpredictable epileptic seizures caused by the abnormal electrical discharge of neurones in various anatomic structures of the CNS is the characteristic feature. This is an approximate definition based on international classifications of seizures and syndromes which take into account the extremely variable clinical and electroencephalographic expression of the disease. The annual incidence of epilepsy is an estimated 20-70 cases per 100,000 inhabitants with a prevalence of 0.4-0.8%. Globally, incidence is higher during childhood, remaining rather stable... 

The usual definition of a neuroprotectant is an agent that aims to prevent neuronal death by inhibiting one or more of the pathophysiological steps in the processes that follow injury to the central nervous system (CNS) or ischemia due to occlusion of an artery or hypoxia due to any cause. This definition has now been extended to include protection against neurodegeneration and neurotoxins. The extended definition includes interventions that slows or halts the progression of neuronal degeneration. 

The medical school definition of multiple sclerosis (MS) is demyelination within the central nervous system that varies in space and time. The term refers to a disorder in which patches of demyelination develop during exacerbations. In the most common forms of MS, exacerbations are separated by varying periods of time in which the disease does not appear to progress. Whether progressive demyelination without clear periods of remission should be considered a form of MS is a matter of definition, about which clinicians specializing in the care of patients with this disorder have argued. Conventional medical nomenclature classifies as distinct entities a number of disorders of myelin that can mimic MS clinically. These include, for instance, the sometimes devastating demyelination localized to the pons or the demyelination that can follow infectious diseases and/or vaccinations. 

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