Rie Nishikata

Oxidative stress may be involved in distant organ failure in tourniquet shock model mice

Crush syndrome is characterized by prolonged shock resulting from extensive muscle damage and multiple organ failure. However, the pathogenesis of multiple organ failure has not yet been completely elucidated. Therefore, we investigated the molecular biological and histopathological aspects of distant organ injury in crush syndrome by using tourniquet shock model mice. DNA microarray analysis of the soleus muscle showed an increase in the mRNA levels of Cox-2, Hsp70, c-fos, and IL-6, at 3h after ischemia/reperfusion injury at the lower extremity. In vivo staining with hematoxylin and eosin (HE) showed edema and degeneration in the soleus muscle, but no change in the distant organs. Immunohistological staining of the HSP70 protein revealed nuclear translocation in the soleus muscle, kidney, liver, and lung. The c-fos mRNA levels were elevated in the soleus muscle, kidney, and liver, displaying nuclear translocation of c-FOS protein. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) analysis suggested the involvement of apoptosis in ischemia/reperfusion injury in the soleus muscle. Apoptotic cells were not found in greater quantities in the kidney. Oxidative stress, as determined using a free radical elective evaluator (d-ROM test), markedly increased after ischemia/reperfusion injury. Therefore, examination of immunohistological changes and determination of oxidative stress are proposed to be useful in evaluating the extent of tourniquet shock, even before changes are observed by HE staining.

Critical contact pressure and transferred energy for soft tissue injury by blunt impact in human-robot interaction

The peak mean contact pressure and the total transferred energy are discussed as the dominant parameters of bruise tolerance by blunt impact in order to obtain safety criteria for robot design in human-robot interaction. Impact tests are conducted using live pigs with the permission of the ethical committee. A 25 mm-diameter cylindrical impactor is used to represent moving parts of robots. Samples of soft tissue are stained, and capillary damages are investigated by microscopy. The results show that there is no capillary damage if the peak mean contact pressure is less than 1.3 MPa and the total transferred energy is less than 87 kJ/m2. The probability of injury as a function of these parameters is obtained using logistic regression of the the experiment results.

Sudden infant deaths from undiagnosed ventricular septal defect - Report of two autopsy cases

Ventricular septal defect (VSD) has a relatively non-aggressive clinical course; either spontaneous closure or causing congestive heart failure treatable with surgical intervention. We present two autopsy cases of sudden infant deaths from clinically undiagnosed VSDs. Case 1 was an 18-day-old boy. As the deceased coughed and became limp after feeding, he was carried to a hospital. Heart murmur was not auscultated there, so he was brought back to home. He presented severe dyspnea and then he was pronounced dead the next day. Case 2 was a 3-week-old boy. Any abnormality was pointed out at physical examination, although his mother felt his wheeze. He developed respiratory arrest at home in the morning and then he was confirmed dead at the hospital. Heart weights of these babies were heavier than mean weights of each normal development. There were perimembranous VSDs in both cases. Histology revealed that the pulmonary arterial walls were thickened. We diagnosed the cause of death in these cases was cardiac collapse with pulmonary hypertension due to VSD. Congenital heart diseases can be diagnosed as early as before birth, because echocardiograph and fetal echography are prevalent in these days. Most VSDs can be noticed by systolic murmur even today. We consider that the failure of initial clinical diagnosis of VSD in primary physical assessment could lead unexpected sudden death. These two cases reminded us to the importance of auscultation which is conventional but as one of the indispensable measure to find a clue for the congenital abnormality.