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Objective To observe the MRI findings of limb gunshot wound and investigate their pathomorphological basis through animal models.Methods Sixteen mongrel dogs were divided into four groups randomly. The hind legs of dogs shot with handgun were undergone 0.5 T MRI scans at 5 h, 24 h, 48 h, and 72 h after wounded, respectively. The gross changes, HE staining light microscopic findings and MRI findings of wounds were observed.Results Permanent tract was a zone of tissue defect. In the tract, blood of 5 h group′s and pus of 24 h, 48 h, and 72 h groups showed T 1WI hypointense signal and T 2WI hyperintense signal. In contusion zone, the main pathological change was homogeneous coagulating necrosis of muscle fibers. MRI images showed irregular line, dot, or block T 1WI isointense signal, T 2WI hypointense signal, and no enhanced after Gd-DTPA injected in all groups. In concussion zone, the main pathological changes of 5 h group were edema, degeneration, and lysis of cells and lots of erythrocytes in the tissue interspace. Besides these, a large quantity of leucocytes and pus cells appeared, the lysis of degenerated cells near the contusion zone and the edema of such area, with passage of time, were more obviously in groups 24 h, 48 h, and 72 h. In MRI, concussion zone showed slightly hypointense T 1WI signal, hyperintense T 2WI, signal and T 2WI signal got higher and the adjacent contusion zone got clearer with time pass. Concussion zone could be enhanced obviously.Conclusion MRI can reflect the lesion of tissue in limb gunshot wound accurately during seventy-two hours after wound. The T 2WI and contrast-enhanced T 1WI are valuable. The special tissue-defect area, coagulating necrosis of cells, and large range injury of blood vessels and cells are the important pathomorphological basis which cause the MRI findings of gunshot wound different from normal trauma.
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The histological and ultrastructural changes in cerebellum of mice exposed whole-body irradiation with high doses of 60Coy-ray were studied in this paper. The animals suffered from acute radiation sickness of CNS form, intermediate form and intestinal form after 16000, 8000 and 4000 rads irradiation respectively. The nuclear shrinkage of the cerebellar granular cells was the most prominent change after irradiation. The cellular necrosis was found only in individural cells. The shrinkage of nucleus, different from necrosis, with characteristic ultrastructural features, tended to recover as manifested by the appearance of nucleolus, increase of free polysomes and well development of Golgi apparatus. It was considered that the cerebellar granular cells were rather resistent to, the radiation. Some pathological changes of small blood vessels in cerebellum were also observed, but was not responsible for the degeneration of the neurons.
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The histopathological and ultrastructural changes in myocardial biopsy material of 6 patients suffering from primary dilated-congestive cardiomyopathy (DCM P) were studied with following findings: 1. In the hypertrophic myocardial cells there were proliferation and hypertrophy of mitochondria, many of which acummulated beneath the cell membrane, producing finger-like projections as well as increasing the cellular volume. The contractile elements of myocardia did not increase in number and showed so- me degenerative changes. 2. Degeneration of myocardia menifested mainly as condensation of myofila-ments, and seemed to be the contributing factor to impairment of myocardial contraction. Hypertrophy and degeneration seemed to be two different stages of the same pathology as transitional changes from one to another were found. 3. Edema, which might proceed to cellular lysis or necrosis, was another manifestation of degeneration of the myocardium. These findings gave the morphologic basis of impairment of myocardial contraction in primary dilated-congestive cardiomyopathy.