ObjectiveTo investigate the changes of ultrastructure of global cerebral ischemia and reperfusion damage in rats.MethodsSix adult male Wistar rats were randomly divided into the ischemia group (n=3), and sham injury group (n=3). Global cerebral ischemia and reperfusion model were established with Pulsinelli's method. Cortical ultrastructure changes were investigated on the first hour after reperfusion.ResultsIn the ischemia group, different degrees of pyconosis neurons, abnormal organell and microtube of neurons were observed. In addition, glial cell and microvessels were damaged in ischemia group, but that in sham injury group were not demaged.ConclusionCortical neurons, neuroglia cells, cytoskeleton and blood-brain barrier changed at early stage of reperfusion damage.

Objective To observe the pathology in temporal lobe cortexes and hippocampus in protopathic intractable temporal lobe epileptics.Methods The cortexes of spike foci in temporal lobe and hippocampus were obtained from 9 cases with protopathic intractable temporal lobe epilepsy who accepted operation.The samples were observed under the transmission electron microscope.Results The ultrastructure changes in spike focus of temporal lobe cortexes are similar to those in hippocampus.It is common that neurons were pycnotic and decreased.Astrocytes were hydropic and degenerative.Gliosis were found in some cases.The number of synapses increased or decreased in different cases and positions.Blood-brain barriers were destroyed because foot processes of astrocytes around capillaries were edematous.Conclusion Neuronal loss,gliosis and synaptic reorganization which occur in epileptic hippocampus and maybe also in epileptic temporal lobe cortexes destroy the balance between excitatory and inhibitory neurotransmission.The abnormalities probably associate with protopathic intractable temporal lobe epileptic seizures.

Objective: To investigate the ultrastructural features of muscle in patients with mitochondrial encephalomyopathy for its diagnosis and differential diagnosis. Methods: The clinical data of 27 mitochondrial encephalomyopathy patients who underwent left or right biceps brachii muscle biopsy at Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University from July 2006 to August 2017 were analyzed retrospectively. The muscle biopsy specimens were examined underlight microscope and transmission electron microscope. Results: There were 27 patients (17 males, 10 females) with an age range of 12 to 62 years (mean 29 years). The age of onset ranged from 3 to 38 years. The course of disease ranged from 1 month to 24 years. Twenty-two cases presented with lactic acidosis and stroke-like episodes (MELAS) syndrome, four with myoclonic epilepsy with ragged red fibers (MERRF) syndrome, and one with chronic progressive paralysis of extraocular muscle (CPEO) syndrome. Skeletal muscle biopsy showed abundant ragged red fibers and strongly SDH-reactive vessel. Genetic studies showed 17 of 22 cases of MELAS syndrome had A3243G mutation, and the other 5 cases had no abnormality. A8344G mutation was found in 3 of 4 cases of MERRF syndrome. No single or multiple mtDNA mutations were found in the single case of CPEO. Transmission electron microscopy of all 27 cases showed diffuse proliferation of mitochondria between the myofibrils and beneath the sarcolemma, with increased spacing between muscle cells. Seven cases showed numerous glycogen and four showed subsarcolemmal lipid droplets, 13 cases showed unusual mitochondrial morphology, including mitochondrial electron-dense substances and paracrystal line inclusions ("parking lot" change)in eight cases. Conclusions Transmission electron microscopy shows significant differences in ultrastructural pathological changes among different patients with mitochondrial encephalomyopathy. Some patients with mild clinical symptoms have increased mitochondrial number, increased metabolism of glycogen and lipid droplets, while others with severe clinical symptoms have abnormal mitochondrial morphology. Typical crystalloid inclusions are found in mitochondria, which are of great value in the diagnosis of this disease.