ABSTRACT
Objective To explore the feasibility,reproducibility and reliability of the T 2* MRI technique in quantifying different concentrations of MnCl2water phantoms at 3.0T.Methods The water phantoms with different concentrations of MnCl2underwent T2* imaging at both 1.5T and 3.0T MRI,and repeated imaging at 3.0T MRI after 1 month.A Spearman correlation was used to determine the relationship of T2* values and Mn concentrations,and established the linear regression equations by using the simple linear regression.W ilcoxon signed-rank sum test and Bland-Altman method were used to evaluate the reproducibility of twice T 2* measurements at 3.0T,and the interclass correlation coefficient(ICC)was calculated.Results T2* values of the phantoms were negatively correlated to Mn concentrations(r= -1.000,P<0.001),and R2* values of the phantoms were positively correlated to Mn concentrations(r=1.000,P<0.001). T2* values of the phantoms measured at 3.0T were positively correlated to that measured at 1.5T(r=1.000,P<0.001).The linear regression equation was T2* 3.0T =0.651T2* 1.5T +0.041.There was no statistical difference of T2* values between the two measurements at 3.0T (Z= -1.732,P=0.083),and ICC was 1.000.Conclusion 3.0T MRI is feasible to quantify cardiac iron deposition.
ABSTRACT
Objective To investigate the protective effects of intra-peritoneal fluid resuscitation on small intestinal mucosa in rats with hemorrhagic shock. Method Fifty Sprague-Dawley (SD) rats were randomly (random number) divided into five groups, namely sham operation group (group I ), hemorrhagic shock group (group Ⅱ ), intra-venous fluid resuscitation group (group Ⅲ ) . intravenous fluid resuscitation plus intra-peritoneal saline resuscitation (group Ⅳ ) and intravenous fluid resuscitation plus intra-peritoneal PD-2 solution resuscitation group (group Ⅴ ). The rats of 5 groups were processed with cannulations of right common carotid artery, right femoral vein and left femoral artery with systemic heparinization. The rat models of hemorrhagic shock were established with modified Wigger' s method by which the blood exsanguinated from left femoral artery. The rats of group Ⅲ were resuscitated with shed blood plus twice equal volume of Ringer's solution after modeling of hemorrhagic shock.The rats of group Ⅳ and group Ⅴ were administered intra-peritoneally with 30 mL saline and 30 mL of 2.5% PD-2 solution, respectively as adjuncts to those used in the group Ⅲ . The specimens of blood and small intestine of rats of all groups were collected 60-120 minutes after modeling and resuscitation. The activity of plasma diamine oxidase (DAO) was determined with chromatometry, the level of plasma D-lactic acid (D-LA) with spectorophotometry and the level of plasma lipopolysaccharide (LPS) with nephelometry. The histopathological and ultrastructure changes of small intestine tissue of rats were observed under light microscope and electronic microscope. Results There were remarkable differences in activity of DAO, and the levels of D-LA and IPS in rats between those ingroup Ⅱ and group I (P <0.01), and between those in group V and groups Ⅱ , Ⅲ or Ⅳ (P <0.05 or P < 0.01) The pathomorphology and ultra-structure of small intestine tissues were severely damaged in group Ⅱ compared with those in group Ⅰ , and those markedly lessened in group V compared with groups Ⅱ , Ⅲ and Ⅳ . Conclusions Intraperitoneal fluid resuscitation with PD-2 solution can significantly protect the integrity of intestinal mucosa and the normal permeability of intestinal wall, and blunts the histopathological changes, and restrains bacterial translocation from gut and reduces the level of plasma endotoxin.
ABSTRACT
Objective To introduce a new design of interlocking system which is easy in use, makes the distal fracture fragments well aligned and rigidly fixated, reduces exposure to radiation for the surgeon and patient, and allows for a decrease in operating time. Methods The new interlocking system was designed to be a self-locking nail with bevels (b-SLN). According to the bevel principle, the axial force of the nail should be turned into a transverse force so as to control the transverse nail's movement. 10 dry-bone simples were made into the fracture model of the middle-femur to test the prototype nail. The retention of the nail in the intramedullary cavity was evaluated by the radiogram. The mechanical properties of a simulated model of single leg loading were tested on the instron-1342 type MTS. Results The prototype nail performed well as designed. The process was stable and reliable. The retention in the intramedullary cavity was fine. The shearing force between the transverse nail and main nail was enough to cut anything around them. The mechanical properties of b-SLN were similar to those of the Grosse-Kempf nail, better than auto fork compress locked intramedullary nail, and much better than MHUA nail and Ender's nail. Conclusions The structure of b-SLN is simple and reliable. There is no focus-point under stress. Its biomechanic properties are satisfactory. It is easy to use with no need of fluoroscopes in the operating theatre.