[Relationship between carotid atherosclerotic plaque characteristics in magnetic resonance imaging and perioperative hemodynamic instability]

Objective: To analyze the relationship between carotid atherosclerotic plaque characteristics in magnetic resonance imaging (MRI) and perioperative hemodynamic instability in patients with severe carotid artery stenosis undergoing carotid artery stenting (CAS). Methods: A total of 89 patients with carotid artery stenosis who underwent CAS treatment at Beijing Tsinghua Changgung Hospital affiliated to Tsinghua University from January 1, 2017, to December 31, 2021, were prospectively included. Among them, 74 were male and 15 were female, with an age range of 43 to 87 years (mean age: 67.8±8.2 years). Preoperative examinations included carotid artery MRI vessel wall imaging to analyze the existence of large lipid-rich necrotic core (LRNC), intraplaque hemorrhage (IPH), and fibrous cap rupture in carotid artery plaques. Plaques without the above-mentioned risk factors were defined as stable plaque group (34 cases), while those with such risk factors were defined as vulnerable plaque group (55 cases). The number of risk factors present in each plaque was also calculated. Intraoperative changes in blood pressure and heart rate were recorded, and the use of dopamine postoperatively was noted. Using the risk factors that the plaque has as independent variables and the clinical outcomes as dependent variables, the RR values were calculated, and the differences in clinical outcomes of patients with different risk factors were compared. Results: The incidence rates of hypotension and bradycardia were higher in patients with vulnerable plaques than those with stable plaques (60.0% (33/55) vs 14.7%(5/34) and 38.2%(21/55) vs 14.7%(5/34), respectively; both P<0.05). Based on MRI imaging features, the large LRNC was present in 45 cases, with RR values for hypotension and bradycardia of 3.15 (1.69-5.87) and 2.20 (1.07-4.53), respectively; IPH was present in 37 cases, with RR values for hypotension and bradycardia of 2.70 (1.61-4.55) and 2.25 (1.15-4.39), respectively; and fibrous cap rupture was present in 29 cases, with RR values for hypotension and bradycardia of 1.50 (0.94-2.40) and 1.29 (0.67-2.49), respectively. The higher the number of risk factors in vulnerable plaques, the higher the incidence of intraoperative blood pressure and heart rate decrease: when the number of risk factors ranged from 0 to 3, the incidence of blood pressure decrease was 14.7% (5/34), 9/18, 11/18, and 13/19, respectively (P<0.001), and the incidence of heart rate decrease was 14.7% (5/34), 6/18, 7/18, and 8/19, respectively (P=0.022). There was no significant difference in the number of cases of dopamine use between the two groups (P>0.05). Conclusion: Patients with a higher number of risk factors for vulnerable carotid plaques, as indicated by carotid artery MRI vessel wall imaging, are at a higher risk of experiencing blood pressure and heart rate decrease during CAS surgery.

[Clinical cohort study of imaging evaluation and postoperative pathology of carotid vulnerable plaque]

Objective: To evaluate the accuracy of contrast-enhanced ultrasound(CEUS) scanning in identifying vulnerable plaque in carotid artery. Methods: The study included a total of 25 patients who suffered from carotid artery stenosis and underwent carotid endarterectomy from January 2016 to December 2017 in Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University. Preoperative carotid artery contrast enhanced ultrasound and High-resolution MRI were performed to all patients to determine whether the plaques were stable. All patients then underwent carotid endarterectomy, during which, plaques were completely removed. Biopsies were performed using HE staining and CD31, CD34 and SMA immunohistochemistry was used to identify the plaques properties, including the thickness and integrity of the fiber cap, neovascular endothelium, hemorrhage, and inflammatory cells in the removed plaques.The results of these tests were compared with the diagnosis through the pre-operative imaging. Results: Among twenty-five cases, the pre-operative CEUS revealed sixteen with unstable plaques and nine with stable plaques. Meanwhile the post-operation pathology confirmed seventeen cases with unstable plaque components. The sensitivity of CEUS in the identification of carotid vulnerable plaque was 88.2%(15/17), the specificity was 87.5%(7/8), and the overall diagnostic accuracy was 88%(22/25). The sensitivity, specificity and overall diagnostic accuracy of high resolution MR for vulnerable plaque identification were 83.3%(10/12), 71.4%(5/7), 78.9%(15/19), respectively. There were no significant difference between two groups(χ(2)=0.003, P>0.05). Conclusions: The sensitivity, specificity and overall diagnostic accuracy of the CEUS for vulnerable plaque identification are high.Therefore, CEUS is recommended as one of the pre-operative diagnostic method for unstable plaque in carotid stenosis.

[A meta-analysis of totally percutaneous access versus open femoral exposure for endovascular aortic aneurysm repair]

Objective: This study was aim to compare the efficacy and safety of percutaneous access and open femoral exposure for endovascular aortic aneurysm repair. Methods: Eligible studies were searched from PubMed, Embase, and Corchrane databases published in English from January 1999 to December 2015. Data extracted from each study were synthesized into overall odds ratios (OR) for technical success rates and complications. The outcomes on technical success rates and complications of both totally percutaneous access and open femoral exposure group were compared. Results: After a systematic review of English language articles, ten studies including 1 504 patients were eligible for the Meta-analysis. The technical success rates of the percutaneous endovascular aortic aneurysm repair (PEVAR) group was 95.1%, close to that of femoral exposure (FE) group (97.5%). The difference did not show significantly (OR=0.57, 95% CI: 0.31-1.04, P>0.05). However, the incidence of total postoperative complications in PEVAR group was 8%, significantly lower than that in FE group (15.9%) (OR=0.52, 95% CI: 0.37-0.42, P<0.01). Conclusion: PEVAR is associated with a similar technical success rate and lower complication incidence rate comparing with FE. Therefore, it could be as a preferred approach of endovascular aortic aneurysm repair.

Development of dual-wavelength fiber ring laser and its application to step-height measurement using self-mixing interferometry

A dual-wavelength erbium-doped fiber (EDF) ring laser was developed and its application to step-height measurement using two-wavelength self-mixing interferometry (SMI) was demonstrated. The fiber laser can emit two different wavelengths without any laser mode competition. It is composed of two EDF laser cavities and employs fiber Bragg gratings to determine which wavelengths are emitted. The step heights can be measured using SMI of the two wavelengths, and the maximum height that can be measured is half the synthetic wavelength of the two wavelengths. A step height of 1mm was constructed using two gauge blocks and then measured using the laser. The measurement was repeated ten times, and the standard deviation of the measurements was 2.4nm.

Evidence for inbreeding depression in the tree Robinia pseudoacacia L. (Fabaceae)

The magnitude of inbreeding depression within populations is important for the evolution and maintenance of mixed mating systems. However, data are sparse on the magnitude of inbreeding depression in Robinia pseudoacacia. In this study, we compared differences in the mature seed set per fruit, seed mass, germination success, and seedling growth between self- and cross-pollination treatments and estimated the inbreeding depression at 3 stages: seed maturation, seedling emergence, and seedling growth at 10 and 20 weeks. We found that progenies resulting from cross-pollination treatments showed significantly higher fitness than progenies resulting from self-pollination, causing high levels of inbreeding depression. Inbreeding depression was not uniformly manifested, however, over the 3 stages. Inbreeding depression was the greatest between fertilization and seed maturation stage (δ = 0.5419), and the seedling emergence (0.3654) stage was second. No significant differences in seedling growth were observed between selfed and crossed progenies. The cumulative inbreeding depression (δ) across all 3 stages averaged 0.7452. Inbreeding depression may promote outcrossing in R. pseudoacacia by acting as a post-pollination barrier to selfing. The large difference in the seed set between self- and cross-pollination that we detected indicated that inbreeding depression would probably be a reasonable explanation for the high abortion and low seed set in R. pseudoacacia.

[Preliminary study on etiology of Budd-Chiari syndrome through clinic and experiment]

OBJECTIVE

To investigate the etiology of Budd-Chiari syndrome (BCS) preliminarily.

METHODS

The clinical findings of radical surgery of 109 cases with BCS from March 2001 to May 2009 were analyzed. The pathological components of membranous tissue (MT) from inferior vena cava (IVC) or hepatic vein (HV) of BCS patients were compared with that of thrombus from deep venous thrombosis (DVT), as well as the expression of transforming growth factor beta receptor (TGF-beta R), platelet derived growth factor receptor (PDGFR), endothelin (ET-1), factor VIII related antigen (FVIII-rAg), ferritin and alpha1-antitrypsin in MTs and thrombus through immunohistochemical method.

RESULTS

One hundred and four cases of BCS were due to IVC and/or HV membrane or thrombosis except that 4 cases due to IVC tumor or 1 case due to compression of fiber. The new-formed IVC membrane was found in 2 recurred cases whose IVC thrombus was excised before 1 year and 7 years. The development from organized thrombus to MT was found in 3 cases of segmental obstruction of IVC. The IVC membrane located below HV outlet was in 8 cases. Both MTs and thrombus had the pathological components such as fibroblast, neutrophil, granulation tissue, newly-formed blood vessels and so on under the light microscope. The expressions of TGF-beta R, PDGFR, ET-1, FVIII-rAg, and ferritin in MTs and thrombus were as follows: MT 72.3%, thrombus 50.0% (P > 0.05); MT 45.5%, thrombus 100% (P < 0.05); MT 100%, thrombus 0 (P < 0.05); MT 90.9%, thrombus 12.5% (P < 0.05); MT 72.3%, thrombus 100% (P > 0.05).

CONCLUSIONS

The membranous tissues and thrombus have the similar homogeneity and cytokines expression. The membrane and thrombus may be different pathological phases.

[The pilot study of the effect of paclitaxel by local slow delivery on intimal hyperplasia of vascular anastomosis after vascular graft bypass]

OBJECTIVE

To develop a new way to prevent restenosis in the anastomotic site due to intimal hyperplasia after vascular graft bypass (VGB) in peripheral arteries.

METHODS

Five mongrel dogs received bilateral iliac-femoral VGB and their arteries between the graft were ligated and cut off under general anaesthesia. The mixture of the paclitaxel and fibrin gel (FG) were randomly sprayed onto one side of grafts including distal and proximal anastomotic site, and the fibrin gel served as control were sprayed onto the other one. The bilateral grafts including distal and proximal anastomotic site were harvested four weeks postoperationally and the anastomotic sites were observed grossly, pathologically and by electron microscopy. The intimal thickness and area of each anastomotic site were measured, then the data were analysed statistically.

RESULTS

The bilateral grafts of all dogs were patent and the neointima of all anastomotic sites have been seen grossly. The neointimal thickness and area of the experimental side were significantly reduced compared with the control side (P < 0.05). Scanning electron microscopy showed that the anastomotic intima of the experimental side was covered with one layer of intact and regular endothelium cells with deposition of little blood components, but the anastomotic intima of the control side was covered with irregular endothelium cells and deposited with a lot of blood cells and fibrins. Transmission electron microscopy showed the anastomotic intima of the control side that rich in vascular smooth muscle cells and the matrix of the intima was composed of regular collagenous fibers, and that of the experimental side consisted of several types of cells with a lot of foreign particles in the matrix.

CONCLUSION

It is safe and effective to locally use low dose of paclitaxel carried by FG in the prevention of vascular anastomotic site intimal hyperplasia. Paclitaxel molecules can penetrate the graft wall and stay in the anastomotic intima more than four weeks postoperationally.

Pharmacokinetics of lactosaminated recombinant human growth hormone in mice

AIM

To study the pharmacokinetic characteristics of lactosaminated recombinant human growth hormone (hGH-L) in mice.

METHODS

The biodistribution was studied with in vivo radioactive tracer technique. The pharmacokinetics was investigated by radioimmunoassay (RIA) method of hGH-L. The results were compared with that of recombinant human growth hormone (hGH).

RESULTS

125I-hGH-L has remarkable livertaxis. The area under drug concentration-time curve (32686.9 microg . min . L-1) in blood and serum mean residence time (21.4 min) of hGH-L are less than that of hGH (36913.1 microg . min . L-1 and 24.9 min) (P < 0.05). In target organ liver, hGH-L distribution half life (1.8 min) and elimination half life (11.1 min) are shorter than that of hGH (2.1 min and 27.7 min) (P < 0.05). The area under drug concentration-time curve (17621.9 microg . min . L-1) of hGH-L is bigger than that of hGH(12148.2 microg . min . L-1) (P < 0.05) in liver.

CONCLUSION

The pharmacokinetic parameters of hGH-L has obvious advantage over that of hGH.