[Estimation of postmortem interval by detecting thickness of cornea using ultrasonic method].

OBJECTIVE: To explore the postmortem changes of cornea thickness measured by ultrasonic pachymetry. METHODS: Eleven rabbits were randomly divided into two groups: one group with intact corneal epithelium and another group without intact corneal epithelium. In the later group, the corneal epithelium of the rabbit was scraped using mechanical elimination method. The corneal thickness was monitored continuously by ultrasonic pachymetry at several postmortem interval points in rabbits of the two groups. The changes of corneal thickness and postmortem interval were explored by relative regression analysis. RESULTS: The thickness of the cornea showed a strong non-linear correlation with the postmortem interval in the group with intact corneal epithelium. The group with intact corneal epithelium showed the correlation coefficient 0.922 and the group without intact corneal epithelium showed the correlation coefficient 0.822, respectively. CONCLUSION: The corneal thickness measured by ultrasonic pachymetry shows a potential value for estimating early postmortem interval. The intact corneal epithelium is a crucial factor for the measurement of cornea thickness by ultrasonic pachymetry.

[Recent progress in research on positional asphyxia of restraint].

Positional asphyxia of restraint means that when an individual was limited in an abnormal body position, asphyxia would take place owing to the disorder of spontaneous respiratory function, and finally it lead to die. So, it belongs to a special type of the mechanical asphyxia. From the cases reported, we could found that it would take place in several conditions. Because the cases were not caused enough recognition, the study has been researched carefully only in recent years. Following the more cases reported, many experts of forensic medicine had investigated it on the mechanism of death and the standard of identification, but they could not reach to agreements. So, they have changed the directions of the researches, began to value the factors of risk and research how to avoid it. In the following text, the mechanism of death, factors of risk, preventive methods, standard of identification and prospecting of positional asphyxia of restraint were reviewed.

[The role of diaphgram fatigue in the death from hanging with bound upper limbs of rabbits].

OBJECTIVE: To explore the role of diaphgram fatigue in the death from hanging with bound upper limbs of rabbits. METHODS: Rabbits were hanged with upper limbs bound, then the data of EMGdi were gathered RESULTS: By analyzing power spectral of EMGdi in experiment, we compare the ratio change of H/L between pre-experiment and post-experiment. There is a significance decrease of the ratio of H/L, so it indicates that diaphgram fatigue does exist. CONCLUSION: Diaphgram fatigue plays an important role in the death from hanging with limbs of rabbits bound.

[Immunohistochemical study of fibronectin in multiple organ dysfunction syndrome in elderly rats].

OBJECTIVE: To study the characteristic of endothelial injuries and the mechanisms of coagulation disorder in multiple organ dysfunction syndrome in elderly rats by observing the distribution and the intensity of fibronectin (FN) expression in important viscerae including the heart, brain, lung, kidney, liver. METHODS: Fifty Wistar rats (one half of them were 3 months old, another half 20 months old) were anaesthetized and cecal ligation puncture (CLP) was done. They were defined as MODS group and MODSE group. Forty Wistar rats (one half of them 3 months old, another half 20 months old) were anaesthetized and laparotomy was done as sham operation group (SOG) and sham operation group in elderly (SOGE). The heart, brain, lung, liver and kidney were harvested and were examined histologically at 6, 12, 24, 48 or 72 hours after operation. They were also stained immunohistochemically by using anti-FN as the first antibody. RESULTS: The expression of FN on the surfaces of vascular endothelial cells in hearts, brains, lungs, livers, kidneys was weakly positive or positive in MODSE, MODS or SOGE group, but it was positive or strongly positive in SOG group. The differences were significant (P<0.05). CONCLUSION: The injury of endothelial cells and the disorders of coagulation system are observed in MODSE, MODS, SOGE groups, especially in MODSE.