Intrauterine fetal brain death is a rare cause of a fixed fetal heart rate pattern. Seven cases have been previously reported in the literature, but only two of them were diagnosed prenatally and all the newborns died soon after delivery. Two additional cases of antepartum diagnosis of intrauterine fetal brain death, managed expectantly, are reported. We had the unique opportunity to document progressive sonographic cerebral changes during the follow-up period, following the neurological event, while the fetus continued life and growth in utero. The cardiographic and sonographic findings suggesting intrauterine fetal brain death were a prolonged fixed fetal heart rate, even following a vibroacoustic and contraction stress test; an atonic fetus without breathing and body movement; and the appearance of hydramnios and the development of ventriculomegaly. 相似文献
4-methylimidazole (4MI) is a compound widely used in various industrial and consumer applications. The most important sources of exposure include chemical caramel coloring, ammoniated molasses, dyes and pigments, rube, cleaning and agricultural chemicals. Toxicity attributed to 4MI in foods has recently become a focus of research. Recent studies showed that 4MI induced adverse changes in various target tissues. Brain is known to be a target organ for 4MI-induced toxicity but its cytotoxic mechanisms have not yet been elucidated. In this study, experiments were divided into two parts: (1) using in vivo methodology, doses of 4MI at 100, 200, or 300 mg/kg were administered orally to mice daily for 14 to obtain brain mitochondria; and (2) utilizing in vitro methodology, brain mitochondria were incubated with 4MI at 400, 800, or 1600 μM concentrations. Subsequently, the neurotoxicity of 4MI was assessed using mitochondrial dysfunction tests, including reactive oxygen species (ROS) formation, mitochondrial membrane potential (MMP) collapse, mitochondrial swelling, and cytochrome c release. Our results from both in vivo and in vitro experiments on isolated brain mitochondria showed a significant decrease in complex II activity and also marked elevation in the ROS formation, MMP collapse, mitochondrial swelling, and enhanced release of cytochrome c. Data indicated that 4MI induced neurotoxicity through the impairment of electron transfer chain especially at complex II and elevated ROS formation leading to subsequent oxidative stress events including mitochondrial membrane depolarization, mitochondrial swelling, and release of cytochrome c, which is the starting point of mitochondrial-mediated apoptosis signaling and neurodegeneration. 相似文献
Abstract The effect of dichlorvos (DDVP) (0–0, dimethyl 2: 2‐dichlorovinyl phosphate), on various lipid fractions and lipid peroxidation in the discrete areas of the brain and spinal cord were studied in the fresh water teleost (Heteropneustes fossilis). Fishes were exposed to three different doses (3.0, 6.0 and 9.0 ppm) of DDVP daily for 7 days. Dose‐related increase in the levels of total lipids, cholesterol and esterified fatty acids was detected in the fore brain, optic lobes, cerebellum, medulla oblongata and spinal cord. However, phospholipids were significantly decreased in the aforementioned regions of the central nervous system. The rate of lipid peroxidation was significantly increased in all the regions of the CNS. 相似文献
Background: Although numerous observational studies have demonstrated a protective effect of motorcycle helmets against head injury, the degree of protection against specific head injury types remains unclear. Experimental biomechanics studies involving cadavers, animals, and computer models have established that head injuries have varying etiologies. This retrospective cross-sectional study compared helmet protection against skull fracture, cerebral contusion, intracranial hemorrhage, and cerebral concussion in a consecutive series of motorcycle operators involved in recent traffic crashes in Kentucky.
Methods: Police collision reports linked to hospital inpatient and emergency department (ED) claims were analyzed for the period 2008 to 2012. Motorcycle operators with known helmet use who were not killed at the crash scene were included in the study. Helmet use was ascertained from the police report. Skull fracture, cerebral contusion, intracranial hemorrhage, and cerebral concussion were identified from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes on the claims records. The relative risks of each type of head injury for helmeted versus unprotected operators were estimated using generalized estimating equations.
Results: Helmets offer substantial protection against skull fracture (relative risk [RR] = 0.31, 95% confidence interval [CI], 0.23, 0.34), cerebral contusion (RR = 0.29, 95% CI, 0.16, 0.53), and intracranial hemorrhage (RR = 0.47, 95% CI, 0.35, 0.63). The findings pertaining to uncomplicated concussion (RR = 0.80, 95% CI, 0.64, 1.01) were inconclusive. A modest protective effect (20% risk reduction) was suggested by the relative risk estimate, but the 95% confidence interval included the null value.
Conclusions: Motorcycle helmets were associated with a 69% reduction in skull fractures, 71% reduction in cerebral contusion, and 53% reduction in intracranial hemorrhage. This study finds that current motorcycle helmets do not protect equally against all types of head injury. Efforts to improve rotational acceleration management in motorcycle helmets should be considered. 相似文献