scholarly journals Study On The Biomechanical Properties Of Rabbit Venous Arterialization

2019 ◽  
Author(s):  
Yuhao Zhang ◽  
Pei Niu ◽  
Zhimin Zhang ◽  
Xiaolong Niu ◽  
Wenzeng Shen ◽  
...  

Abstract Objective : To investigate the mechanisms underlying restenosis following coronary artery bypass grafting using bridging veins.Method : We established a rabbit model of venous arterialisation, by transplanting veins into the arterial system as bridging vessels and investigated vessel tensile mechanical and histomorphological properties. Result : Control vein elasticity (k = 16.20) was less than that of the control artery (k = 58.04; P < 0.05), and vein walls were thinner. Following venous arterialisation, proliferating cell nuclear antigen and alpha-actin were upregulated and vein walls thickened (P < 0.05), with elasticity after venous arterialisation (k = 86.26) significantly higher than that of control veins (P < 0.05). Conclusion : This indicates that venous intima is damaged by high pressure following arterialisation, resulting in gradual restenosis, with thickening of the venous intima and an increase in vessel elasticity. Clinically, there is potential to repeat these experiments to determine the elastic extremum of the great saphenous vein and control the pressure in the lumen of this vessel, to ensure minimal damage to the intima before anastomosis, thereby facilitating improvement of long-term patency rates following vein bridge surgery. Whether the increase in venous bridge elasticity after venous arterialisation can be controlled, with the aim of preventing early-stage restenosis, warrants investigation.

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ho Seok Chung ◽  
Seung Hwan Moon ◽  
Soon-Suk Kang ◽  
Minseop Kim ◽  
Hun Lee ◽  
...  

This study aimed to evaluate and compare the effectiveness of a newly developed epithelial removal brush with conventional methods in a rabbit model of corneal epithelial defects. The corneal epithelia of thirty-seven rabbits were removed by three different methods including blades (blade group), newly developed epithelial brushes (Ocu group), and conventional rotating brushes (Amo group). The defect area was measured with light microscopy immediately and at 4, 18, 24, and 50 hours after removal. Corneas were obtained immediately and at 24 and 50 hours and subjected to hematoxylin and eosin (H&E) and immunofluorescence staining using proliferating cell nuclear antigen (PCNA) and phosphorylated heat shock protein 27 (pHSP27) antibodies. The residual stromal surface was observed by scanning electron microscopy (SEM). In the Ocu group, epithelia were significantly recovered at 18, 24, and 50 hours compared with immediately after removal, and in the blade and Amo groups, epithelia were significantly recovered only at 50 hours after epithelial removal. The expression levels of PCNA and pHSP27 did not differ among three groups. There was significantly more inflammatory cell infiltration in the blade group than in the other groups. SEM showed a more regular and uniform residual stromal surface in the Ocu group than in the other groups. The newly developed epithelial brush showed better polishing ability and led to earlier significant epithelial recovery and a more regular and uniform stromal surface than conventional methods in this rabbit model of epithelial defects. Accumulation of clinical data is expected to expand the scope of application of new brushes for laser surface ablation.


1996 ◽  
Vol 09 (03) ◽  
pp. 95-100 ◽  
Author(s):  
G. Li ◽  
A. H. R. W. Simpson ◽  
J. Kenwright ◽  
J. T. Triffitt

SummaryAn experimental model of leg lengthening has been used to study the cellular responses of the regenerating bone to different rates of distraction. Cell proliferation were assessed by detection of proliferating cell nuclear antigen using a monoclonal antibody, PC10. The technique was verified by comparison with bromodeoxyuridine uptake and subsequent detection with specific antibody (Bu20A). The positive staining index (PSI) was calculated for a variety of tissues and the PC10 PSI was greater than that of Bu20A, as described by the expression: PC10 PSI = 1.6 Bu20A PSI + 12.9, with a correlation coefficient 0.79. The results suggest that PC10 may be used as an alternative marker to assess cell proliferation in rabbit regenerating bone tissue. In addition, the rate of cell proliferation during leg-lengthening was found to reach a maximum at a distraction rate of 0.7 mm/day without further change at higher rates.Cell proliferation was assessed in an experimental system of leg-lengthening by two separate methods. The presence of proliferating cell nuclear antigen or the uptake of bromodeoxyuridine were determined immuno-histochemically. Both methods indicated cell proliferation during leg-lengthening reaches a maximum at a distraction rate of 0.7 mm/day.


Reproduction ◽  
2005 ◽  
Vol 129 (1) ◽  
pp. 89-102 ◽  
Author(s):  
L M McClusky

To understand the processes involved in the spatial and temporal maturation of testicular cells in Squalus acanthias, we used standard morphometry, proliferating-cell nuclear antigen (PCNA) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) immunohistochemistry. Except for immature spermatocysts (germinal zone, GZ; early-stage pre-meiotic, E-PrM), the number of cysts in all subsequent stages and the total number of cysts in the spermatogenic progression varied seasonally. The spermatogenic cycle spans about 2 years and is interrupted by germcell clone deletion via apoptosis at the mitosis–meiosis transition in April/May, manifesting as a zone of degeneration (ZD). Rate of displacement of the ZD across the testis diameter indicates that late-stage premeiotic (L-PrM) generations 12–13 require 9–10 months to reach the mature-spermatid stage. Also, the number of cysts completing spermatogenesis is approximately 4–5-fold less than the number that entered spermatogenesis proper 2 years earlier. Pronounced gonocytogenesis in the germinal ridge was coincident with ZD formation in April/May, but it was absent in the fall when mature spermatogonial and meiotic activities had resumed. Whereas strong Sertoli cell PCNA immunoreactivity dominated the GZ cyst cell-cycle activities throughout the year, except during the spring/summer months, the spermatogonial- and Sertoli-cell PCNA indices in E-PrM cysts were inversely related. PCNA immunoreactivity in spermatocytes was seasonal and dependent on the stage of meiosis. TUNEL labelling was limited to spermatogonia and increased stage-dependently in the PrM region (L-PrM = mid-stage PrM ≫E-PrM ≫GZ), correlating with ZD formation, in a season-dependent manner. Results imply that effects of normal regulatory factors in Squalus are stage- and process-specific.


2016 ◽  
pp. 86-90
Author(s):  
Gerald Caspers ◽  
Klaus Nammert ◽  
Holger Fersterra ◽  
Hartmut Hafemann

Fluidised-bed steam dryers have been in use for industrial-scale drying of pressed beet pulp for more than 20 years. This highly energy-efficient process can be considered to be state of the art in the industry. Scientific laboratory and pilot-plant testing have provided the basis for a detailed description of the principles of fluidisation and drying in superheated water vapour. Advances in production data acquisition, in particular regarding the options for the real-time presentation and evaluation of high-resolution operating data (Industry 4.0), have opened up new potentials for optimisation of the drying process in fluidised-bed steam dryers. By analysing and interpreting sequences of events, or simultaneous events, it is now possible to analyse process behaviour in great depth. This allows malfunctions to be avoided by improved design or, assisted by suitable measuring and control systems, to be detected at an early stage. Failures can then be prevented altogether by initiating automated countermeasures. On the basis of more recent insights gained from the analysis of faults and disruptions using modern operating data acquisition, BMA’s fluidised-bed steam dryer (WVT) has been subjected to fundamental technological and technical improvements, so it now meets today’s demands for efficiency and reliability. Modifications include the product inlet, the distribution plate and several other parts, in addition to the known and patented PPS (Plug Protection System; EP 2457649 B1), and the patented rotary weir (EP 2146167 B1).


Pathology ◽  
2021 ◽  
Vol 53 ◽  
pp. S47
Author(s):  
Christine Bundell ◽  
Mathew Krummenacher ◽  
Elina Tan ◽  
Paul Sjollema ◽  
Nick Acquarola ◽  
...  

Author(s):  
Jinbao Zhang ◽  
Jaeyoung Lee

Abstract This study has two main objectives: (i) to analyse the effect of travel characteristics on the spreading of disease, and (ii) to determine the effect of COVID-19 on travel behaviour at the individual level. First, the study analyses the effect of passenger volume and the proportions of different modes of travel on the spread of COVID-19 in the early stage. The developed spatial autoregressive model shows that total passenger volume and proportions of air and railway passenger volumes are positively associated with the cumulative confirmed cases. Second, a questionnaire is analysed to determine changes in travel behaviour after COVID-19. The results indicate that the number of total trips considerably decreased. Public transport usage decreased by 20.5%, while private car usage increased by 6.4%. Then the factors affecting the changes in travel behaviour are analysed by logit models. The findings reveal significant factors, including gender, occupation and travel restriction. It is expected that the findings from this study would be helpful for management and control of traffic during a pandemic.


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