Toxoplasmosis of the central nervous system

Toxoplasmosis is usually an asymptomatic infection, but symptomatic cases are becoming more common with the rise in AIDS cases and the increased number of patients receiving immunosuppressive therapy. Toxoplasmosis of the central nervous system occurs most often in immunocompromised hosts. Brain biopsy may be necessary for diagnosis. Pyrimethamine and sulfadiazine are active against T. gondii, but they do not affect the encysted organisms.     

Clinical polymorphism of herpetic lesions of the central nervous system

Four groups of herpetic affection of the central nervous system have been described: meningitis, meningoencephalitis, encephalitis and encephalomyelitis. Each condition has a variety of neurological manifestations. Clinico-pathogenic aspects of the problem are discussed.     

Animal models, hypertension, and central nervous system mechanisms.

Accumulating evidence suggests that the central nervous system plays a fundamental role in chronic hypertension. On the other hand, the means by which nervous factors influence the long-term control of blood pressure remain obscure. Animal models that replicate some of the functional aspects of essential hypertension in man have been of value and continue to provide insight into the complexity of the problem. Although none of the experimental models gives definitive answers, separate and combined analyses suggest the multiplicity of sites at which the stimulus must be applied for blood pressure to remain elevated.     

HIV and the central nervous system

Neurological complications of HIV infection are common with clinically recognized disorders ultimately affecting between 40% and 75% of patients. The spectrum of neurological disease is broad. This article highlights the common disorders of the central nervous system associated with HIV/AIDS.     

Alcohol and the central nervous system

Acute Wernicke-Korsakoff syndrome is an underdiagnosed cause of reversible coma in the alcoholic patient. Chronic toxic effects of ethanol include nutritional polyneuropathy, cerebellar degeneration, and diffuse cortical damage with resultant alcoholic dementia. The rapid correction of hyponatremia can result in the iatrogenic syndrome of central pontine myelinolysis.     

Clinical concerns in the ultrasound exposure of the developing central nervous system

Neurosonography is used as a primary imaging modality worldwide for visualization of the developing brain and spinal cord in fetuses, infants and children. During the entire process of brain development, there is rapid cell turnover, a condition that is favorable for genetic mutations once external stimuli are applied. No clinical studies in humans have been performed specifically to discuss the long-term impact of postnatal ultrasound exposure of the central nervous system. Currently published studies concerning the prenatal and postnatal use of Doppler or of ultrasound contrast agent use and the developing central nervous system are insufficient to draw meaningful conclusions regarding safety. By instituting a standardized examination and following appropriate patient handling guidelines, the risk of an adverse outcome associated with neurosonography is minimized. This paper recommends adoption of the ALARA principle and offers suggestions as to how to minimize the risk of adverse effects in neurosonography.     

Hemoglobin potentiates central nervous system damage.

Iron and iron compounds--including mammalian hemoglobins--catalyze hydroxyl radical production and lipid peroxidation. To determine whether hemoglobin-mediated lipid peroxidation might be important in hemorrhagic injuries to the central nervous system (CNS), we studied the effects of purified hemoglobin on CNS homogenates and injected hemoglobin into the spinal cords of anesthetized cats. Hemoglobin markedly inhibits Na/K ATPase activity in CNS homogenates and spinal cords of living cats. Hemoglobin also catalyzes substantial peroxidation of CNS lipids. Importantly, the potent iron chelator, desferrioxamine, blocks these adverse effects of hemoglobin, both in vitro and in vivo. Because desferrioxamine is not known to interact with heme iron, these results indicate that free iron, derived from hemoglobin, is the proximate toxic species. Overall, our data suggest that hemoglobin, released from red cells after trauma, can promote tissue injury through iron-dependent mechanisms. Suppression of this damage by desferrioxamine suggests a rational therapeutic approach to management of trauma-induced CNS injury.     

肾移植后中枢神经系统并发症的临床诊疗

背景：目前国内外关于肾移植后中枢神经系统并发症的研究较少。目的：探讨肾移植后中枢神经系统并发症的临床诊疗方案。方法：对河南中医学院第一附属医院2008-01/2010-08收治的277例同种异体肾移植后出现中枢神经系统并发症的15例患者进行回顾性分析。结果与结论：15例（5.41%）出现中枢神经系统并发症的患者中：弥漫性脑病7例（2.52%）,脑血管意外4例（1.44%）,癫痫发作3例（1.08%）,中枢神经系统感染1例（0.36%）。提示肾移植后中枢神经系统原因较复杂,包括感染、缺氧、代谢、电解质紊乱、移植后排斥反应及免疫抑制剂（钙调蛋白抑制剂）等。     

AIDS of the central nervous system

The central nervous system of nearly every HIV-positive patient becomes affected by the AIDS virus itself or by one of the associated diseases during the course of the illness. Early diagnosis of lesions which demand therapeutic consequences is of the most importance concerning prolongation of life and improvement in its quality. In spite of the frequent underestimation of cerebral involvement by imaging methods and their unspecific findings they are often the only diagnostic means which permit-timely diagnosis and, at least in some diseases, therapeutic monitoring. Indications for cranial computed tomography (CCT) or magnetic resonance tomography (MRT) are already present with mild or transient neurological or psychiatric symptoms or the extracerebral manifestation of neurotropic organisms or tumours which metastasize to the brain, even in patients without subjective complaints.     

Ultrasound and the developing central nervous system

The potential risk of ultrasonography resulting in adverse biologic effects is particularly important in neurosonographic applications of diagnostic ultrasound in medicine. Key issues relate to the likelihood of producing bioeffects from the level of acoustic output emitted from modern diagnostically powerful ultrasound equipment. Important elements in the assessment of risk include the sensitivity of the tissue structures under examination, the standards of practice in clinical use and the presence of biologic effects identified from laboratory experimentation or from human studies. The World Federation for Ultrasound in Medicine and Biology continues to support activities related to evaluating bioeffects and safety of ultrasound. This paper includes extracts of some of the presentations given during the latest safety meeting, a mini-symposium on "ultrasound and the developing fetal central nervous system" held in conjunction with the WFUMB Congress in May 2000. The speakers covered topics ranging from physics of estimating heating from ultrasound equipment in clinical use to actual measurement of ultrasound-induced intracranial temperature increases in animal fetuses. Finally, some practical scanning strategies were proposed to minimise risk of adverse outcome in various clinical neurosonographic practices.     

Relationship between the immune system and the diseases of the central nervous system.

Considering the eventual role of non-specific cell-mediated immune reactions in the pathogenesis of Parkinson's syndrome based on the destruction of dopaminergic cells of the substantia nigra the killer cell activity of patients suffering from this disease has been examined. According to the results the killer cell activity of Parkinson patients is significantly lower in the age group below 60 years as compared to the higher age groups. When comparing the age groups below 60 years, significantly lower activity was measured in the patients than in the controls. Killer cell activity is significantly higher in patients suffering from more severe conditions (Hoehn-Yahr's stage IV-V) when compared to the milder cases. These results suggest the possibility that killer cell-mediated ADCC reaction may play a role in the pathogenesis of the disease. The results of these examinations open new therapeutic perspectives. It may be hoped that, as a result of our increasing knowledge and technical progress in immunology, the damaged immune system could be selectively influenced and target specific immune therapy could be used in the near future by means of for instance inactivations of cytotoxic cells, elimination of antibodies or other immunological methods.