Background: Hepatic Myelopathy (HM) is a rare complication of chronic liver disease usually associated with extensive portosystemic shunt of blood, which has been created surgically or has occurred spontaneously, causing progressive... more
Background: Hepatic Myelopathy (HM) is a rare complication of chronic liver disease usually associated with extensive portosystemic shunt of blood, which has been created surgically or has occurred spontaneously, causing progressive spastic paraparesis. Some single cases or short clinical reports describing patients suffering from HM have been published worldwide, but are often scattered. Material and method: One additional case of HM with typical symptoms was presented, and a retrospective survey of the literature in a manner of comprehensive review was undertaken. Results: 46 case reports with 98 patients of HM including ours have been eligibly selected. General information on all cases was summarized. Detailed analysis of the clinical characteristics of HM patients was undertaken. Conclusion: Liver cirrhosis caused by hepatitis B infection and alcoholism is the most frequent causes of HM. Portosystemic shunt which resulted in chronic exposure to toxic substances bypassing the liver play an important role in the pathogenesis. The pathology study consistently disclosed a selective and symmetrical severe loss of myelin in both lateral pyramidal tracts. The predominant neurologic abnormality of HM is the progressive spasticity and weakness in the lower extremities. A typical manifestations, such as triparesis or quadriparesis, sensory deficit, urinary or bladder incontinence and non-pyramidal manifestations such as dysarthria, tremor and ataxia can also occur, which render the disorder more complicated to be diagnosed. Plasma ammonia concentrations were frequently found to be elevated. MEP provides evidence of the early diagnosis of HM and assesses different degrees of neurological involvement. The spinal cord MRI imaging shows no abnormality. Abnormalities of brain magnetic resonance combined with syndrome of brain dysfunction, hepatocerebral degeneration should be taken into consideration. Appending case studies suggest that liver transplantation is a promising therapeutic strategy.
Animal-mediated seed dispersal by frugivorous birds and mammals is central to the ecology and functioning of ecosystems, but whether and how frugivory-related traits have affected plant speciation remains little explored. Fruit size is... more
Animal-mediated seed dispersal by frugivorous birds and mammals is central to the ecology and functioning of ecosystems, but whether and how frugivory-related traits have affected plant speciation remains little explored. Fruit size is directly linked to plant dispersal capacity and therefore influences gene flow and genetic divergence of plant populations. Using a global species-level phylogeny with comprehensive data on fruit sizes and plant species distributions, we test whether fruit size has affected speciation rates of palms (Arecaceae), a plant family characteristic of tropical rainforests. Globally, the results reveal that palms with small fruit sizes have increased speciation rates compared with those with large (megafaunal) fruits. Speciation of small-fruited palms is particularly high in the understory of tropical rainforests in the New World, and on islands in the Old World. This suggests that frugivory-related traits in combination with geography and the movement behavi...
