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Objective@#To compare and quantify the differences in size-specific dose estimates (SSDE) obtained by effective diameter and water-equivalent diameter from the central slice of the scan range in head CT examination.@*Methods@#A total of 111 consecutive adult patients who underwent head CT examination were enrolled in this study. All of CTDIvol values in the dose report were documented. The dataset was assigned into group A and group B, based on the individual size-dependent conversion factors (f) of effective diameter (deff) and water-equivalent diameter (dw) at the central slice multiplied by normalized volume computed tomography dose index (CTDIvol ) respectively. Body size, f and SSDE were calculated. With SSDEgross served as the reference level, the performance of SSDEdeff and SSDEdw was evaluated.@*Results@#Statistically significant differences were found in body size (t=47.587, P<0.05) and f(z=-9.242, P<0.05) between group A and group B. Statistically significant difference also existed in SSDE (t=-46.687, P<0.05), (56.20±2.66) and (53.49±2.48) mGy for group A and group B respectively. Strongly positive correlation was shown in body size (r=0.873, R2 =0.761) and SSDE (r=0.974, R2 =0.949) between group A and group B(all P<0.05). Positive correlation was also found between SSDEdeff and SSDEgross(r=0.900, R2 =0.809), SSDEdw and SSDEgross (r=0.904, R2 =0.817, all P<0.05). Mean absolute difference was 2.34 and 0.78 mGy, for SSDEdeff vs. SSDEgross and SSDEdw vs. SSDEgross respectively; mean absolute relative difference was 4.38%, 1.40%; root mean square difference was 1.17 mGy (2.17%), 1.06 mGy (1.91%). Interquartile range and full range of SSDEdeff and SSDEdw were 3.22 vs. 2.39 mGy, 13.65 vs. 12.48mGy, respectively. A less degree of variation was observed in SSDEdw than that in SSDEdeff.@*Conclusions@#SSDEdw values based on the water-equivalent diameter at the central slice of the scan range got better agreement with those derived from all slices, which could serve as a simpler and more valid indicator to represent the average value of size-specific dose estimates of the whole scan range in head CT examination.
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Objective To explore the validity of the size-specific dose estimate (SSDE) derived from the water-equivalent diameter (Dw)value of the slice located in the middle of the scan range in the head CT examination. Methods A total of 197 patients underwent head CT nonenhanced scan were enrolled in this retrospective study. The Dw, size-dependent conversion factor (f), normalized volume CT dose index (CTDIvol) and SSDE values of all slices were calculated. Two sets of SSDE, SSDEgroand SSDEcenbased on the Dwvalues slice by slice (Dw-gro) and the Dwvalues of the slices in the middle of the scan range (Dw-cen), were obtained across all patients. Pearson correlation analysis and linear regression analysis were performed for Dw-grovs Dw-cen, Spearman correlation analysis and linear regression analysis for SSDEgrovs SSDEcen, SSDE vs Dw, CTDIvolvs Dw. With the reference of SSDEgrovalue, mean absolute relative difference (MARD) of SSDEcen values were calculated to assess its accuracy and the correlated factors of MARD was analyzed with multivariate linear stepwise regression analysis. Results The minimal Dwvalue close to the roof of the skull corresponded to the maximal value of f and SSDE, which was the minimal value of CTDIvol. The significant positive correlation was showed between Dw-grovs Dw-cen, SSDEgrovs SSDEcen, SSDE vs Dw, CTDIvolvs Dw(r=0.947, 0.931, 0.416, 0.626;P＜0.05). The values of Dw,groand Dw-cenwere (16.94±0.69) and (18.50±0.62) cm respectively. The values of SSDEgroand SSDEcenwere [54.10 (52.29, 56.39)] mGy and [53.77 (51.85, 55.25)] mGy respectively. An approximation of SSDEcenvalues with an average of 1.62% of the gross MARD was found to match the reference value. Multivariate linear stepwise regression analysis indicated that MARD had negative correlation with Dw(β=–1.319,P＜0.05), positive correlation with CTDIvol(β=0.202,P＜0.05), and f was not included in the multivariate regression equation. Conclusion SSDEcenbased on the Dwvalue of the slice located at the center of the scan range yields small MARD value and can represent a reliable SSDE estimation in the head CT examination.
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Aim To investigate the expression of stro-mal interaction molecule 1 (STIM1) in rat pulmonary arterial hypertension ( PAH ) tissues and effects of STIM1 on arterial muscle cells proliferation. Methods PAH was induced by a single intraperitoneal injec-tion of MCT at a dose of 60 mg·kg - 1 . The mRNA or protein expressions of STIM1 in monocrotaline-induced pulmonary hypertensive rats were measured by real-time PCR or Western blot, respectively. The arterial smooth muscle cells A7R5 were transiently transfected with STIM1 plasmids to prepare STIM1 overexpressed cells. Cell proliferations were detected by using CCK-8 kits. The expressions of Akt/ mTOR pathway molecules of A7R5 were measured by Western blot. Results The right ventricular systolic blood pressure ( RVSP) and right ventricular mass index ( RVMI ) were markedly elevated in MCT-treated rats (P < 0. 01) in comparison to control rats. The mRNA and protein ex-pression levels of STIM1 in monocrotaline-induced pul-monary hypertensive rats were 2. 19 and 1. 66 folds of control rats, respectively. STIM1 were transiently over-expressed in cultured A7R5. Cells transfected with STIM1 grew more quickly than non-transfected control. Overexpression of STIM1 significantly increased the phosphorylation of Akt, mTOR, p70-S6K, and 4E-BP1, but did not change their protein expression lev-els. Conclusion STIM1 are over-expressed in rat PAH tissues. Overexpression of STIM1 can promote ar-terial smooth muscle cells proliferation by regulating Akt/ mTOR pathway.
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Aim To investigate the effect of store-oper-ated calcium channel( SOCC) on autophagy in rat arte-rial smooth muscle cells A7 R5 . Methods Lentiviruses containing STIM1 or Orai1 gene were packaged in 293 T cells and then were used to infect rat arterial smooth muscle cells A7 R5 . The expression levels of STIM1 , Orai1 and Beclin 1 , a critical autophagy-regu-lating protein, of lentivirus-infected A7R5 cells, were detected by Western-blot. Autophagy in lentivirus-in-fected A7 R5 cells was induced by starvation or rapamy-cin, an inhibitor of mammalian target of rapamycin ( mTOR ) . Autophagy marker LC3 of these cells was detected by Western-blot. Results The constructions of vector pLV-STIM1 and pLV-Orai1 were confirmed by restriction enzymes digestion analysis. Compared with the control group, expressions of STIM1 or Orai1 protein was significantly increased after lentivirusLV-STIM1 and LV-Orai1infection, whereas the expressions of autophagy related protein Beclin-1 were down-regu-lated. Starvation or rapamycin stimulated A7R5 auto-phagy but overexpression of STIM1 or Orai1 significant-ly inhibited starvation or rapamycin induced autoph-agy. Conclusion Overexpression of store-operated calcium channel components STIM1 and/or Orai1 in rat arterial smooth muscle cells A7 R5 inhibit autoph-agy. This mechanism might contribute to the develop-ment of pulmonary arterial hypertension.
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Objective To explore significance of alpha‐fetoprotein isoform L2(AFP‐L2) in the screening of Down syndrome in pregnant women ,so as to provide references for clinical application .Methods A total of 250 healthy pregnant women and 22 preg‐nant women with Down syndrome were enrolled in this study .Serum specimens were collected and AFP‐12 was separated and cap‐tured by using the magnetic bal ,time‐resolved fluorescence immunoassay was used to detect levels of AFP and AFP‐L2 ,and the percentage of AFP‐L2 (AFP‐L2% ) was calculated .Results The serum level of AFP of pregnant women with Down syndrome [(20.2±4.2)ng/mL]was lower than that of healthy pregnant women[(46.7±19.9)ng/mL],and had statistically significant difference(P<0 .05) .Serum AFP‐L2% of pregnant women with Down syndrome was higher than that of healthy pregnant women , and had statistically significant difference(P<0 .05) .Conclusion Detection of AFP level and AFP‐L2% could be an indicator for Dow n syndrome screening .
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It is difficult to select the appropriate ventilation mode in clinical mechanical ventilation. This paper presents a nonlinear multi-compartment lung model to solve the difficulty. The purpose is to optimize respiratory airflow patterns and get the minimum of the work of inspiratory phrase and lung volume acceleration, minimum of the elastic potential energy and rapidity of airflow rate changes of expiratory phrase. Sigmoidal function is used to smooth the respiratory function of nonlinear equations. The equations are established to solve nonlinear boundary conditions BVP, and finally the problem was solved with gradient descent method. Experimental results showed that lung volume and the rate of airflow after optimization had good sensitivity and convergence speed. The results provide a theoretical basis for the development of multivariable controller monitoring critically ill mechanically ventilated patients.