Objective To observe the morphologic characteristics of the post-traumatic cerebral infarction and discriminate it from brain contusion. Methods From 81 severe brain injury samples 15 were selected which met the criteria of the secondary necrosis and hemorrhage of brain. Another 15 simple brain contusion samples were selected as control. They were cut according to various requirements either coronary or saggittally or horizontally and observed grossly and histologically. Results The post-traumatic cerebral infarctions were found mainly in 5 localities: basal ganglia (3 cases), cingulate gyrus (2 cases), both cuneus of the occipital lobes (2 cases), lateral occipito-temporal gyrus (6 cases, 5 of them complicated with hemorrhage in the midbrain and pons), and occipital gyrus (2 cases). All of the infarctions were located not at the point of coup or contrecoup. They were localized and had clear boundaries. All of the lesions could be traced back to be related to brain hernia. Microscopically, there were extravasation of blood, and necrosis in the infarction, and usually severe congestion and edema with white blood cells infiltration and glia cell reaction. If the lesion was in the cerebrum, it was usually located at the junction of cortex and medulla, in severe cases extended to whole thickness of the cortex and the subarachnoid space, but the pia mater was not ruptured. There were marked ischemic and hypoxia changes in the neurons. The lesions of brain contusion, on the contrary, were always ruptured. The contused brain tissue may be necrotic. Conclusion The Post-traumatic cerebral infarction is synonymous with secondary necrosis and hemorrhage of the brain. The mechanism of the infarction is compression of intra-cerebral blood vessels due to cerebral hernia. It could be differentiated from cerebral contusion by the relation with cerebral hernia, the location of the lesion, the in-tactness of the pia mater, as well as other related histological changes.

Objective To investigate the relationship between the type of gliding contusion and its mechanism with site of force.Methods The site undergoing contusion and ways of force are respectively determined by skull anatomy location and details of these cases.Then,the 132 specimens of brain,which have been fixed by formalin,are sliced in coronal section and sagittal section and stained with HE,observed under microscope.ResultsGliding brain contusion could appeared at the top and bottom region of brain respectively.Top-injury type,were observed in 65 cases(49.24%),base-injury type,were found in 38 cases(28.78%).There were 29 cases(21.96%) in which contusion could be found at both top and base of brain,we called mixed type.We found that the injury area depend on the ways of force-act:the top-injury type mostly caused by the force on cupular part of pars zygomatica in acceleration,the base-injury type mainly caused by the force on occipitalia in deceleration and the mixed type caused by the force on the boundry of the calvaria and occipital in deceleration.Conclusion The type of gliding contusion is relevant with mechanism and site of force.

To explore the demarcation between the normal variation and the developemental anomaly of the cardiac conduction system (CCS). Using the method of sampling CCS designed by this research group, CCS of 737 cases died of non cardiac causes of death and 149 cases died of sudden cardiac deaths were sampled, serial sections were made, stained with HE method or Masson trichrome method,and observed under the light microscope.Results:(1)There were morphological variations in size, position and structure of normal human CCS; (2) In 4 cases died of sudden cardiac deaths, developemental anomalies were found in both AVN and HB. The morphological variations observed in our cases include: displacement of the bifurcation of HB into the pars membrancea of the interventricular septum,of the HB toward the left or the left lower sides of the interventricular septum or of less than 1/2 AVN into the central fibrous body , as well as of ordinary cardiomyfibers into the HB or BB. The developmental anomalies observed in our cases include: preservation of fetal type AVN in adults, displacement of whole AVN into the central fibrous body, complete division of HB into more than 3 bundles, and the displacement of the bifurcating portion of HB into the root of tricupid valves.

Objective To study the pathological changes related to cardiac sudden death. Methods The CCS from 179 cases with cardiac sudden death were examined histopathologically. Result There were 8 cases with hemorrhage, inflammation, or tumor infiltration in the cardiac nervous tissue or cardiac ganglion. Pathological changes such as edema, degeneration or necrosis could be found in the nervous tissue. However, no lethal pathological changes were observed out of cardiac nervous tissue. Conclusion Either primary or sencondary pathological changes in the cardiac nervous tissue might cause sudden death.

Objective To study the ultrastructural changes of gunshot wounds at the brain stem and the cause of the death. Method A case died of the head injury and two cases died of gunshot wounds of the brain stem were studied. Brain stem tissues were taken 25 min after death. Tissue blocks from the tegmentum of the midbrain and the pons as well as the gray matter of the medulla oblongata in the deep portion of the base of the fourth ventricle were taken and were examined with ultramicroscopy and scanning electron microscopy. Results (1) The gunshot wound injuries inside the brain including burn and injuries caused by punch and pressure; (2) Although the primary gunshot wounds were located at the midbrain, the pathological changes extended to the whole brain stem; (3)The injuries of the axons and the nerve cells were more severe and extensive than those of the glia fibers. (4)The changes of the burn included condensation and degeneration of the myelin sheath and axonal cytoplasm, especially the mitochondria as well as edema of the myelin sheath and the axonal cytoplasm. The punch and pressure injuries included the torsion, deformation, fusion, compression, breach, torn and displacement of the axons with loss of cytoplasm as well as the deviation of mitochondria, micro ?neuro - fibrils and micro - tubules in the axons. Conclusion The severe and extensive injuries of the axons of nerve fibers in the brain stem might play an important role in the cause of death of gunshot.

Objective To study the relations between the site of head injury and the position of brain edema induced tentorial notch herniation (TNH). Method The formalin fixed brain specimens of 91 cases were cut either coronally, or sagittally or horizontally, according to different requirement. Then, the characteristics of injury were observed. Results There were three types of brain edema induced TNH after cerebral injury: 65 cases with anterior herniation (71.4%), 5 cases with posterior herniation (5.5%), and 21 cases with unilateral or bilateral total herniation (23.1%). Anterior herniation was notable among 16 cases with total herniation. Conclusion Frontotemporal anterior herniation was the most common type of TNH after cerebral injury. The occurrence of TNH was related to the site and manner of injury, as well as the strength of force and survival interval after injury.

Objectlve To study the significance of injury and posthumous changes to the axonal in brain stem and provide evidence to the forensic discrimination of brainstem injury. Methods Select the cases that died of the primary brainstem injury or other disease randomly, All cases were divided into control group and experimental group, control group and experimental group that were autopsied at the postmortem interval less than 24h or 48h, or longer than 24h or 48h. The brainstem tissue were cut and stained by silver; Two hundred four samples were observed in microscope and selected 9～10 widest axonal to measure its diameter, then analysis the data. Results There is significant difference in axonal diameter of midbrain and mudella between control group (not including those cases died of cardiovascular diseases) and experiment group (P0.05). Conclusion The axonal swelling of the brainstem is closely related with the traumatic injury, so axonal swelling is a finding useful for identification of traumatic brainstem lesions, but death from cardiovascular diseases should be excluded.

Objective Observe the injuries to the cranial nerves in cases of brain stem injury following head trauma;explore the mechanism of injuries and their relations to the mode and point of impact on the head. Method Brain stem specimens of 465 cases of head trauma were designed to take cross sections at the roots of the 3rd～12th cranial nerves. Among the 465 cases, 171 were proven to have contusion of the brain stem. On these cases, the cranial nerves were observed meticulously. Results Cranial nerve injuries were found in all cases suffering from brain stem contusion. The nerves included were: oculomotor nerve (120 cases, 70.2%), facial and acoustic nerve (92 cases, 53.8%), trigeminal nerve (85 cases, 49.7%), abducent nerve (45 cases, 26.3%), hypoglossal nerve (31 cases, 18.1%), vagus nerve (27 cases, 15.8%), glosso-pharyngeal nerve (24 cases, 14.0%), and trochlear nerve and accessory nerve (10 cases each, 5.8%). The nerve injuries may be unilateral or bilateral, involving single or multiple nerves in a case. The pathological changes included hemorrhage (42 cases, 24.6%), edema (26 cases, 15.2%), structural deformation at the root of the nerves (71 cases, 41.5%), tear of the nerve roots (32 cases, 18.7%). Conclusion Cranial nerve injury is an important part of the cranio-cerebral injury, and also an accompaniment of the brain stem injury. The features of interesting in the injuries were the higher frequencies in the nerves at the upper level and the nerves of larger diameter; of highest frequency were oculomotor nerve, facial nerve and acoustic nerve.

BACKGROUND:Epithelial cel s are commonly used as the seed cel in tissue engineering;however, there is stil a lack of an effective in vivo noninvasive trace technology. OBJECTIVE:To investigate the feasibility of labeling canine oral epithelial cel s with ultrasmal superparamagnetie iron oxide (USPIO) and magnetic resonance imaging (MRI) in vitro. METHODS:Oral epithelial cel s from beagles were primary cultured, and then labeled by 0.75 mg/L poly-L-lysine combined with USPIO (0, 5, 10, 25, 50 and 100 mg/L), respectively. To determine the optimal dosage, the intracel ular iron expression was identified by Prussian blue staining, and the cel viability in different groups was detected by cel counting kit-8. Final y, 2×105 labeled cel s were suspended with 1 mL PBS buffer, and were screened using 3.0 T MR on T2*WI sequences in vitro. RESULTS AND CONCLUSION:USPIO prepared with 0.75 mg/L poly-L-lysine could successful y label dog oral epithelial cel s. Prussian blue staining showed intracel ular blue spots, and the intracel ular blue spots became more with the concentration increasing and saturated at the concentration of 25 mg/L. Cel counting kit-8 indicated that the cel viability did not change when the concentration<25 mg/L. Among the T2*WI sequences, the MRI signal intensity decreased with the concentration increasing. In conclusion, canine oral epithelial cel s can be effectively labeled with USPIO making no impact on cel viability when the concentration<25 mg/L, and MRI can be used to track these labeled cel s in vitro.

Tumors of the cardiac conduction system (CCS) have rarely been reported. The CCS from 198 cardiac-related deaths (GroupⅠ),and 838 deaths from non-cardiovascular diseases or trauma (Group Ⅱ ), were studied. Sampling was done of the sinoatrial node (SAN)and atrio-ventricular node (AVN) along their long axis of each node as a single block and the His bundle (HB) perpendicular to its long axis in 2-4 blocks. Five-micron serial sections were made; tissue slices were taken intermittently, every 20th from the SAN, every 10th from the AVN, and every 30th from the HB and bundle branches (BB), by continuous slices three times. Tumors in the CCS were found in 12 cases (1.155 %), where 10 (0.965%) were primary tumors, and 2 (0.193%) were metastatic tumors. The primary tumors included 4 fibromata compressing the HB (0.386 %), 4 hemangiomata (0.386%), 1 AVN tumor (0.097 %), and 1 rhabdomyoma (0.097 %). In 8 of the 10 cases, the tumors were located in the AVN or HB. The metastatic tumors originated from lymphocytic leukemia and malignant lymphoma (histiocytic type) in lung, and were all found in the SAN. Of the 12 cases, 2 were from the group Ⅰ. Tumors in the CCS are the smallest tumors in different parts of the body, which can cause sudden death.