Objective To analysis and determine the possibility of the Citellus undulatus infected with Yersinia pestis surviving the winter in an experimental study, and to provide scientific experimental basis for the study on the mechanism of Yersinia pestis preservation. Method In 2006,09 to 2007,04 and 2007,09 to 2008,04 in Xinjiang Wusu-Gurtu natural foci of plague, under natural conditions, the over the winter process of Citellus undulatus carrying the plague bacteria was simulated, and 178 Citellus undulatus were infected with Yersinia pestis (1×107 Bacteria/mouse) using artificial injection method. One hundred seventy-eight Citellus undulatus infected with Yersinia pestis were kept into a construction of the black (1-5 ℃) basement (2 meters under the ground) in the plague focus. In doing so, these Citellus undulatuses almost simultaneously stepped into hibernation. After waking up from hibernation in following year in April, the survived mice carrying the plague bacteria were observed. Results Sixty-eight mice survived among the 178 infected with Yersinia pestis after 6 months of hibernation (through October to the following year in April), and the remaining 110 were all dead without pulling through the hibernation period. The survival rate was 38.2% (68/178). The organ culture of Yersinia pestis of the 110 dead mice(Citellus undnlatus) were tested, 67 were negative(-), 43 positive(+), with a positive rate of 39.1%(43/110). Among the rats with positive plague bacteria, the congestive pulmonary edema and the pathological changes of the hemorrhagic inflammation of the heart, liver, spleen, kidney and injection site could be seen clearly; the plague-free mice were not found to have any pathological changes. The survived 68 mice over the winter were autopsied and observed after being fed up for 20 days. No any pathological changes were found among these mice, and culturing of Yersinia pestis of the heart, liver, spleen, lungs and the tissue of injection site of these mice were all negative (-). Conclusions Citellus undulatus can carry Yersinia pestis during hibernation, but some fail to carry the bacteria through the entire process of hibernation persistently. Yersinia pestis was negative in the survived mice at the end of hibernation. The results showed that Citellus undulatus can not carry Yersinia pestis over the winter.

OBJECTIVETo determine the indication, optimal operative procedures, plan and the estimation of the prognosis depending on the subtype of aortic dissection defined by the extension and extent of dissection.

METHODSThe outcome of 708 patients with aortic dissection between January 1994 and December 2004 was analyzed. Among them 477 patients suffered from Stanford type A aortic dissection were treated. Type A dissection can be classified into 3 subtypes based on the pathological change of the aortic root. Type A1 (No pathological change type): 212 patients underwent ascending aorta replacements; Type A2 (mild pathological change type): 63 patients underwent ascending aortic replacement with concomitant aortic valve and valsalva sinus plasty and David procedure was performed in 9 patients; Type A3 (severe pathological change type): 193 patients underwent Bentall procedure. The method of aortic arch repair was determined by the pathological type of distal aorta. Total aortic arch replacement was performed in 78 patients with complex type (type C). There hundred and ninety-nine patients with simple type (type S) underwent partial aortic arch replacement. 231 patients suffered from Stanford type B aortic dissection. Type B dissection can be classified into 3 subtypes based on dilated extension of proximal descending aorta. Type B1 (no dilation was confined in the proximal of thoracic descending aorta): endoluminal stent graft repair was performed in 103 patients. Replacement of the partial proximal thoracic descending aorta and replacement combined with stented elephant trunk procedure were performed in 32 and 12 patients respectively; Type B2 (aneurysm in thoracic descending aorta): 32 patients underwent the part proximal thoracic descending aorta replacement combined with aorta plasty. 21 patients underwent the replacement of entire thoracic descending aorta; Type B3 (aneurysm in thoracic descending and abdominal aorta): thoracoabdominal aortic replacement was operated in 31 patients with deep hypothermia circulatory arrest; Type BC (complex type): 44 patients were performed the operation with the use of deep hypothermia circulatory arrest because their left subclavian arteries or distal aortic arch were affected by the dissection; Type BS (simple type): 103 patients were underwent endoluminal stent graft repair. In the 60 patients, the operations were performed by using the technique which preserved blood was transfused back by pump via the femoral artery. Femoro-femoral bypass was performed in 24 patients.

RESULTSType A: the operative mortality was 4.6% (27/477), and the hospital morbidity was 14.5% (69/477). Type B: the hospital mortality of endoluminal stent graft repair was 1.9% (2/103). 9.7% (10/103) had mild leakage from proximal communications. The morbidity was 2.9% (3/103) in stent group. The mortality was 3.1% (4/128), and the hospital morbidity was 18.8% (24/128) in the operative group.

CONCLUSIONThe subtype of aortic dissection is much useful in determining the optimal procedure, operative indication and plan, estimating the prognosis.

Adult ; Aged ; Aged, 80 and over ; Aneurysm, Dissecting ; classification ; pathology ; therapy ; Aortic Aneurysm ; classification ; pathology ; therapy ; Female ; Humans ; Male ; Middle Aged ; Prognosis ; Retrospective Studies ; Stents ; Treatment Outcome ; Vascular Surgical Procedures ; methods