The main composition of MRI system is introduced including magnet,gradient-RF system,cooling system,reconstruction system and operation system.According to the principle and functions of every component,the common troubles and the corresponding reasons of MRI system in using are analyzed,and the solutions are presented.[Chinese Medical Equipment Journal,2008,29(2):90,93]

Objective To prove whether it is availble to define the penumbra histopathologically and immunohistopathologically by observing the MRI T 2 imaging,cytoskeleton and neuron changing. Methods Seven cases of autopsy infarct brain with different ischemic time were studied in our program. By MRI T 2 imaging, the fixed brains were examined. Large section of whole brain, and small section of different parts,in and out of the infarct area, and the opposite hemisphere were observed. After observing the neuron, cytoskeleton, microglia, astrocyte, vessel, and also some cytokines by histological and immunohistochemical methods, we divide the ischemic and surrounding areas into four different parts as to seeing the different changes. Results In area 0, the neuron, gliocyte and vessel were all necrotic, eosinocytes developed, and cytoskeletons disappeared. In area 1, there were large number of dark neurons, shrinking cells with heavily destroyed, cytoskeleton, active microglia and inflammatory cells. In area 2, there were a few ischemic neurons , a few dark neurons, and normal neurons,and were also lots of active astrocyte and microglial. The proportion of area 2 was reduced sharply in two days. The ischemic proportion shown by MRI was smaller than that shown by large section of the whole brain. MRI T 2 imaging showed only the area 0 and area 1 with T 2 value increasing, and not showed the area 2 with normal T 2 value. In area 3, the cells were all in normal shape.However,the active microglia and astrocyte hyperplasia, together with the positive TGF ? and TNF? expression, existed in area 3 in all seven brains.Conclusions Area 0 is the infracted mature area, area 1 is the irreversible area, both of them are centers of the necrotic area. Combined with MRI, neuron and cytoskeleton changes, we conclude that area 2 is the possible reversible damage area, or the equal area of penumbra. Area 3 is the response area to ischemic damage, which in some authors’studies was called‘penumbra’.

The present study evaluated the effect of non-thermal plasma on skin wound healing in BalB/c mice. Two 6-mm wounds along the both sides of the spine were created on the back of each mouse (n=80) by using a punch biopsy. The mice were assigned randomly into two groups, with 40 animals in each group: a non-thermal plasma group in which the mice were treated with the non-thermal plasma; a control group in which the mice were left to heal naturally. Wound healing was evaluated on postoperative days (POD) 4, 7, 10 and 14 (n=5 per group in each POD) by percentage of wound closure. The mice was euthanized on POD 1, 4, 7, 10, 14, 21, 28 and 35 (n=1 in each POD). The wounds were removed, routinely fixed, paraffin-embedded, sectioned and HE-stained. A modified scoring system was used to evaluate the wounds. The results showed that acute inflammation peaked on POD 4 in non-thermal plasma group, earlier than in control group in which acute inflammation reached a peak on POD 7, and the acute inflammation scores were much lower in non-thermal group than in control group on POD 7 (P<0.05). The amount of granular tissue was greater on POD 4 and 7 in non-thermal group than in control group (P<0.05). The re-epithelialization score and the neovasularization score were increased significantly in non-thermal group when compared with control group on POD 7 and 10 (P<0.05 for all). The count of bacterial colonies was 10(3) CFU/mL on POD 4 and <20 CFU/mL on POD 7, significantly lower than that in control group (10(9) CFU/mL on POD 4 and >10(12) CFU/mL on the POD 7) (P<0.05). It was suggested that the non-thermal plasma facilitates the wound healing by suppressing bacterial colonization.

The present study evaluated the effect of non-thermal plasma on skin wound healing in BalB/c mice.Two 6-mm wounds along the both sides of the spine were created on the back of each mouse (n=80) by using a punch biopsy.The mice were assigned randomly into two groups,with 40animals in each group:a non-thermal plasma group in which the mice were treated with the non-thermal plasma; a control group in which the mice were left to heal naturally.Wound healing was evaluated on postoperative days (POD) 4,7,10 and 14 (n=5 per group in each POD) by percentage of wound closure.The mice was euthanized on POD 1,4,7,10,14,21,28 and 35 (n=1 in each POD).The wounds were removed,routinely fixed,paraffin-embedded,sectioned and HE-stained.A modified scoring system was used to evaluate the wounds.The results showed that acute inflammation peaked on POD 4 in non-thermal plasma group,earlier than in control group in which acute inflammation reached a peak on POD 7,and the acute inflammation scores were much lower in non-thermal group than in control group on POD7 (P＜0.05).The amount of granular tissue was greater on POD 4 and 7 in non-thermal group than in control group (P＜0.05).The re-epithelialization score and the neovasularization score were increased significantly in non-thermal group when compared with control group on POD 7 and 10 (P＜0.05 for all).The count of bacterial colonies was 103 CFU/mL on POD 4 and ＜20 CFU/mL on POD 7,significantly lower than that in control group (109 CFU/mL on POD 4 and ＞1012 CFU/mL on the POD 7) (P＜0.05).It was suggested that the non-thermal plasma facilitates the wound healing by suppressing bacterial colonization.