Objective:To investigate the effect of chrysophanol(CHR)on cartilage injury in rats with osteoarthritis and its mechanism of regulating SIRT1/HMGB1/NF-κB signal pathway.Methods:Rat models of osteoarthritis were established and divided into negative control group,chrysophanol low(CHR-L,10 mg/kg),middle(CHR-M,20 mg/kg),high dose group(CHR-H,40 mg/kg),SIRT1 inhibitor(sirtinol 5 mg/kg)+chrysophanol high dose group(sirtinol+CHR-H),and normal healthy control group was set up.The degree of joint swelling was measured,and the inflammatory index was evaluated;the pain threshold(tenderness and heat pain)was measured;HE staining and safranine O staining were applied to detect the pathological changes of rat articular cartilage;the levels of serum inflammatory factors(IL-6,IL-1β,TNF-α)were detected by ELISA method;oxidative stress indexes(MDA,SOD,GSH-PX)were detected by micro method;TUNEL staining was used to detect apoptosis;Western blot was used to detect the protein expressions of SIRT1,HMGB1,NF-κB p65,p-NF-κB p65,MMP-13 and C-Caspase-3.Results:Compared with the normal healthy control group,the rats in negative control group had obvious pathological injury,such as destruction of articular cartilage structure,necrosis and reduction of chondrocytes,the joint swelling degree,arthritis index,levels of IL-6,IL-1β,TNF-α,content of MDA,chondrocyte apoptosis rate,expressions of apoptotic protein C-Caspase-3,HMGB1,NF-κB p65/p-NF-κB p65,MMP-13 proteins increased obviously,the tenderness threshold,heat pain threshold,activities of SOD,GSH-PX,and the expression of SIRT1 protein decreased obviously(P<0.05);compared with negative control group,the pathological injury of articular cartilage in CHR group improved obviously with the increase of dosage,the joint swelling degree,arthritis index,levels of IL-6,IL-1β,TNF-α,content of MDA,chondrocyte apoptosis rate,expression of apoptotic protein C-Caspase-3,HMGB1,NF-κB p65/p-NF-κB p65,MMP-13 proteins decreased obviously,the tenderness threshold,heat pain threshold,activities of SOD,GSH-PX,and the expression of SIRT1 protein increased obviously(P<0.05);compared with CHR-H group,sirtinol+CHR-H group was able to reverse the protective effect of CHR on cartilage injury to a certain extent.Conclusion:CHR can reduce the inflammation of articular cartilage,inhibit the apoptosis of chondrocytes and play a protective role in the cartilage injury of osteoarthritis rats by up-regulating the expression of SIRT1 and down-regulating the expressions of HMGB1 and NF-κB p65/p-NF-κB p65.

Objective:To evaluate the effect of dexmedetomidine on the viability of dopaminergic neurons in the ventral tegmental area (VTA) of morphine-addicted mice.Methods:Experiment Ⅰ Thirty SPF healthy adult male C57BL/6 mice, aged 8 weeks, weighing 20-25 g, were divided into 3 groups ( n=10 each) using the random number table method: normal saline group (NS group), dexmedetomidine 50 μg/kg group (DEX50 group), and dexmedetomidine 100 μg/kg group (DEX100 group). A morphine addiction model was established by intraperitoneal injection of increasing doses of morphine (10, 20, 30, 40, 50 and 50 mg/kg) for 6 consecutive days in mice. After the successful establishment of the model, dexmedetomidine 50 and 100 μg/kg were intraperitoneally injected for 14 consecutive days in group DEX50 and group DEX100 respectively, while normal saline was given instead in group C. The conditioned place preference (CPP) experiment was conducted every other day. Experiment Ⅱ Thirty SPF healthy adult male C57BL/6 mice, aged 8 weeks, weighing 20-25 g, were divided into 3 groups ( n=10 each) by the random number table method: control group (C group), morphine group (Mor group) and dexmedetomidine 50 μg/kg group (DEX50 group). Normal saline was intraperitoneally injected for 10 consecutive days in group C. Morphine with increasing doses was intraperitoneally injected for 6 days, and then normal saline was intraperitoneally injected for 4 consecutive days in group Mor. Morphine with increasing doses was intraperitoneally injected for 6 days, and then dexmedetomidine 50 μg/kg was intraperitoneally injected for 4 consecutive days in group DEX50. The mice were anesthetized at 90 min after the last intraperitoneal injection, brain tissues were harvested, and the corresponding brain slices of the VTA were selected for c-Fos immunofluorescence staining. Experiment Ⅲ Ten dopamine transporter-Cre recombinase mice were divided into 2 groups ( n=5 each) by the random number table method: morphine group (Mor group) and morphine+ dexmedetomidine 50 μg/kg group (Mor+ DEX group). Stereotaxic viral injection was performed in the brain. rAAV-EF1α-DIO-GCaMP6s was injected into the VTA and an optical fiber was implanted. Three weeks later, a morphine addiction model was established based on Experiment Ⅰ for the CPP experiment, morphine was intraperitoneally injected in group Mor, and morphine and dexmedetomidine were intraperitoneally injected in group Mor+ DEX. The viral fluorescence signals were recorded at 5 min before and 20 min after the drug administration in the three groups. Results:Experiment Ⅰ There was no statistically significant difference in the CPP scores after developing the morphine addiction model among the three groups ( P>0.05). Compared with group NS, the CPP scores were significantly decreased at 4-14 days of the continuous administration in group DEX50 and group DEX100 ( P<0.05). Experiment Ⅱ Compared with group C, the number of c-Fos positive cells in the VTA was significantly increased in group Mor ( P<0.05). Compared with group Mor, the number of c-Fos positive cells in the VTA was significantly decreased in group DEX ( P<0.05). Experiment Ⅲ Compared with that before administration, the calcium signals of dopaminergic neurons in the VTA were significantly enhanced in group Mor ( P<0.05), and no statistically significant difference was found in the calcium signals of dopaminergic neurons in the VTA in group Mor+ DEX ( P>0.05). Compared with group Mor, no statistically significant difference was found in the calcium signals of dopaminergic neurons in the VTA before drug administration ( P>0.05), and the calcium signals of dopaminergic neurons in the VTA were significantly weakened after administration in group Mor+ DEX ( P<0.05). Conclusions:The mechanism by which dexmedetomidine promotes the extinction of morphine addiction is related to the inhibition of the viability of dopaminergic neurons in the VTA of mice.

Objective:To elucidate the epidemiological characteristics and temporal trends of out-of-hospital cardiac arrest (OHCA) in Shenzhen.Methods:Retrospective data on OHCA cases managed by emergency medical services (EMS) and admitted to network hospitals in Shenzhen from January 1, 2011 to December 31, 2022, were collected following the Utstein template. Demographic characteristics, event information, treatment, and resuscitation outcomes were included. Descriptive statistics, Joinpoint time trend analysis and a multivariate logistic regression were employed to identify factors influencing the return of spontaneous circulation (ROSC) after prehospital resuscitation.Results:A total of 46 053 EMS-accessed OHCA were included, of which 16 330 (35.46%) received EMS resuscitation. The crude incidence of EMS-accessed OHCA increased significantly from 15.51 per 100 000 in 2011 to 44.73 per 100 000 in 2022, with a significant overall upward trend (AAPC=11.83%, 95% CI: 8.33%-15.44%, P<0.001). Among EMS-treated OHCA, the bystander cardiopulmonary resuscitation (CPR) rate rose from 5.11% to 20.90% (AAPC=13.68%, 95% CI: 9.11%-18.44%, P<0.001), while prehospital ROSC rates increased from 2.33% to 8.62% (AAPC=17.53%, 95% CI: 13.01%-22.23%, P<0.001), both showing significant upward trends. Among EMS-treated OHCA patients, those with events occurring in public places (a OR=1.28, 95% CI: 1.06-1.55, P=0.006), presumed cardiovascular etiology (a OR=1.95, 95% CI: 1.65-2.32, P<0.001), initial shockable rhythm on monitoring (a OR=2.56, 95% CI: 1.08-3.15, P<0.001), bystander CPR (a OR=1.43, 95% CI: 1.16-1.76, P<0.001), airway opening (a OR=2.39, 95% CI: 1.70-3.46, P<0.001), and defibrillation (a OR=1.29, 95% CI: 1.06-1.57, P=0.010) had higher ROSC rates. Conversely, males (a OR=0.67, 95% CI: 0.55-0.81, P<0.001), the older (a OR=0.99, 95% CI: 0.98-0.99, P<0.001), and longer symptom onset to call 120 time of [10, 20) min (a OR=0.52, 95% CI: 0.39-0.70, P<0.001), [20, 30) min (a OR=0.33, 95% CI: 0.24-0.47, P<0.001), and ≥ 30 min (a OR=0.35, 95% CI: 0.25-0.49, P<0.001) were associated with lower prehospital resuscitation success rates. Conclusions:The incidence of OHCA in Shenzhen exhibited a significant upward trend from 2011 to 2022. Public location of arrest and early recognition-intervention were critical determinants of outcomes. Enhancing prehospital ROSC requires targeted improvements in the prehospital survival chain, including widespread public CPR training and optimized EMS accessibility.

Objective:To evaluate the effect of dexmedetomidine on the viability of dopaminergic neurons in the ventral tegmental area (VTA) of morphine-addicted mice.Methods:Experiment Ⅰ Thirty SPF healthy adult male C57BL/6 mice, aged 8 weeks, weighing 20-25 g, were divided into 3 groups ( n=10 each) using the random number table method: normal saline group (NS group), dexmedetomidine 50 μg/kg group (DEX50 group), and dexmedetomidine 100 μg/kg group (DEX100 group). A morphine addiction model was established by intraperitoneal injection of increasing doses of morphine (10, 20, 30, 40, 50 and 50 mg/kg) for 6 consecutive days in mice. After the successful establishment of the model, dexmedetomidine 50 and 100 μg/kg were intraperitoneally injected for 14 consecutive days in group DEX50 and group DEX100 respectively, while normal saline was given instead in group C. The conditioned place preference (CPP) experiment was conducted every other day. Experiment Ⅱ Thirty SPF healthy adult male C57BL/6 mice, aged 8 weeks, weighing 20-25 g, were divided into 3 groups ( n=10 each) by the random number table method: control group (C group), morphine group (Mor group) and dexmedetomidine 50 μg/kg group (DEX50 group). Normal saline was intraperitoneally injected for 10 consecutive days in group C. Morphine with increasing doses was intraperitoneally injected for 6 days, and then normal saline was intraperitoneally injected for 4 consecutive days in group Mor. Morphine with increasing doses was intraperitoneally injected for 6 days, and then dexmedetomidine 50 μg/kg was intraperitoneally injected for 4 consecutive days in group DEX50. The mice were anesthetized at 90 min after the last intraperitoneal injection, brain tissues were harvested, and the corresponding brain slices of the VTA were selected for c-Fos immunofluorescence staining. Experiment Ⅲ Ten dopamine transporter-Cre recombinase mice were divided into 2 groups ( n=5 each) by the random number table method: morphine group (Mor group) and morphine+ dexmedetomidine 50 μg/kg group (Mor+ DEX group). Stereotaxic viral injection was performed in the brain. rAAV-EF1α-DIO-GCaMP6s was injected into the VTA and an optical fiber was implanted. Three weeks later, a morphine addiction model was established based on Experiment Ⅰ for the CPP experiment, morphine was intraperitoneally injected in group Mor, and morphine and dexmedetomidine were intraperitoneally injected in group Mor+ DEX. The viral fluorescence signals were recorded at 5 min before and 20 min after the drug administration in the three groups. Results:Experiment Ⅰ There was no statistically significant difference in the CPP scores after developing the morphine addiction model among the three groups ( P>0.05). Compared with group NS, the CPP scores were significantly decreased at 4-14 days of the continuous administration in group DEX50 and group DEX100 ( P<0.05). Experiment Ⅱ Compared with group C, the number of c-Fos positive cells in the VTA was significantly increased in group Mor ( P<0.05). Compared with group Mor, the number of c-Fos positive cells in the VTA was significantly decreased in group DEX ( P<0.05). Experiment Ⅲ Compared with that before administration, the calcium signals of dopaminergic neurons in the VTA were significantly enhanced in group Mor ( P<0.05), and no statistically significant difference was found in the calcium signals of dopaminergic neurons in the VTA in group Mor+ DEX ( P>0.05). Compared with group Mor, no statistically significant difference was found in the calcium signals of dopaminergic neurons in the VTA before drug administration ( P>0.05), and the calcium signals of dopaminergic neurons in the VTA were significantly weakened after administration in group Mor+ DEX ( P<0.05). Conclusions:The mechanism by which dexmedetomidine promotes the extinction of morphine addiction is related to the inhibition of the viability of dopaminergic neurons in the VTA of mice.

Objective:To investigate the effect of chrysophanol(CHR)on cartilage injury in rats with osteoarthritis and its mechanism of regulating SIRT1/HMGB1/NF-κB signal pathway.Methods:Rat models of osteoarthritis were established and divided into negative control group,chrysophanol low(CHR-L,10 mg/kg),middle(CHR-M,20 mg/kg),high dose group(CHR-H,40 mg/kg),SIRT1 inhibitor(sirtinol 5 mg/kg)+chrysophanol high dose group(sirtinol+CHR-H),and normal healthy control group was set up.The degree of joint swelling was measured,and the inflammatory index was evaluated;the pain threshold(tenderness and heat pain)was measured;HE staining and safranine O staining were applied to detect the pathological changes of rat articular cartilage;the levels of serum inflammatory factors(IL-6,IL-1β,TNF-α)were detected by ELISA method;oxidative stress indexes(MDA,SOD,GSH-PX)were detected by micro method;TUNEL staining was used to detect apoptosis;Western blot was used to detect the protein expressions of SIRT1,HMGB1,NF-κB p65,p-NF-κB p65,MMP-13 and C-Caspase-3.Results:Compared with the normal healthy control group,the rats in negative control group had obvious pathological injury,such as destruction of articular cartilage structure,necrosis and reduction of chondrocytes,the joint swelling degree,arthritis index,levels of IL-6,IL-1β,TNF-α,content of MDA,chondrocyte apoptosis rate,expressions of apoptotic protein C-Caspase-3,HMGB1,NF-κB p65/p-NF-κB p65,MMP-13 proteins increased obviously,the tenderness threshold,heat pain threshold,activities of SOD,GSH-PX,and the expression of SIRT1 protein decreased obviously(P<0.05);compared with negative control group,the pathological injury of articular cartilage in CHR group improved obviously with the increase of dosage,the joint swelling degree,arthritis index,levels of IL-6,IL-1β,TNF-α,content of MDA,chondrocyte apoptosis rate,expression of apoptotic protein C-Caspase-3,HMGB1,NF-κB p65/p-NF-κB p65,MMP-13 proteins decreased obviously,the tenderness threshold,heat pain threshold,activities of SOD,GSH-PX,and the expression of SIRT1 protein increased obviously(P<0.05);compared with CHR-H group,sirtinol+CHR-H group was able to reverse the protective effect of CHR on cartilage injury to a certain extent.Conclusion:CHR can reduce the inflammation of articular cartilage,inhibit the apoptosis of chondrocytes and play a protective role in the cartilage injury of osteoarthritis rats by up-regulating the expression of SIRT1 and down-regulating the expressions of HMGB1 and NF-κB p65/p-NF-κB p65.

Ketosis in dairy cows is often accompanied by apoptotic and inflammatory responses in adipose tissue.In order to investigate the effect of pro-apoptotic protein Bid on adipocyte apoptosis in cows with ketosis,the adipose tissue was stained by TUNEL staining technique in this study to observe the apoptotic changes in adipose tissue of cows with ketosis.In the in vivo test,protein ex-pression of apoptosis-related factors Bid,Bax,C-Caspase-3,Bcl-2 and inflammation marker factors C1q,IL-1β,IL-10 and IL-6 in adipose tissues of healthy cows and ketosis cows were detected by Western blot.In the in vitro assay,the adipocyte lipolysis model was constructed by culturing pri-mary bovine adipocytes in vitro to inhibit Bid and adding isoproterenol(ISO),and the protein ex-pression levels of apoptosis-related molecules and inflammation-related molecules in adipocytes were detected by Western blot technique.The results of TUNEL staining showed that the protein expression of pro-apoptotic factors Bid,Bax and C-Caspase-3,and pro-inflammatory markers TNF-a,IL-1β,and IL-6 were significantly higher,and the protein expression of complement C1q,anti-ap-optotic factor Bcl-2,and anti-inflammatory factor IL-10 were significantly lower in adipose tissues of ketosis cows compared with that of healthy cows.The in vitro results showed that the protein expression levels of apoptosis and inflammation-related factors in adipocytes treated with the ISO group were significantly higher compared with those in the control group,while the protein ex-pression levels of apoptosis and inflammation-related factors in adipocytes treated with the addi-tion of the Bid inhibitor group were significantly lower.The above results showed that inhibition of Bid could alleviate the apoptotic and inflammatory responses of ISO on adipocytes.This will fur-ther clarify the role of Bid/C1q in the regulation of adipose tissue and cell apoptosis and inflamma-tion in ketosis cows.

OBJECTIVE: To explore the genetic basis for four patients suspected for Marfan syndrome (MFS). METHODS: Four male patients with suspected MFS and their family members who were treated at West China Second Hospital of Sichuan University from September 12, 2019 to March 27, 2021 were selected as the study subjects. Peripheral venous blood samples were collected from the patients and their parents or other pedigree members for the extraction of genomic DNA. Whole exome sequencing was carried out, and candidate variants were validated by Sanger sequencing. The pathogenicity of the variants was determined based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). RESULTS: Genetic testing revealed that all four patients have harbored variants of the FBN1 gene, including c.430_433del (p.His144fs) deletional variant in exon 5, c.493C>T (p.Arg165*) nonsense variant in exon 6, c.5304_5306del (p.Asp1768del) deletional variant in exon 44 and c.5165C>G (p.Ser1722Cys) missense variant in exon 42. According to the ACMG guidelines, the c.430_433del and c.493C>T were classified as pathogenic variants (PVS1+PM2_Supporting+PP4; PVS1+PS1+PS2+PM2_Supporting+PP4). c.5304_5306del and c.5165C>G were classified as likely pathogenic variants (PS2+PM2_Supporting+PM4+PP4; PS2_Moderate+PS1+PM1+PM2_Supporting). CONCLUSION The c.430_433del and c.5304_5306del variants of the FBN1 gene identified in this study were unreported previously. Above results have enriched the variation spectrum of the FBN1 gene and provided a basis for genetic counseling and prenatal diagnosis of patients with MFS and acromicric dysplasia.
Female ; Pregnancy ; Humans ; Male ; Exons ; China ; Family ; Genetic Counseling ; Genetic Testing ; Marfan Syndrome/genetics* ; Mutation ; Fibrillin-1/genetics*

AIM: To investigate the effects of phorbol ester (TPA) on the anti-tumor effect and renal toxicity of cisplatin (CP). METHODS: MTT assay was used to examine the effect of TPA on the proliferation inhibition of CP in A549 and SPC-A-1 lung cancer cells. Also the effect of TPA on acute toxicity of CP was observed by once injection of high dose CP through caudal vein; The tumor-bearing mice model was explored to investigate the effect of TPA on tumor inhibition ratio and renal toxicity of CP in vivo. And the effect of TPA on renal oxidative stress induced by CP was detected. RESULTS: 1 ng/mL TPA could significantly enhance the inhibitory effect of CP on cell proliferation. In acute toxicity test, TPA could significantly reduce the toxicity of CP and prolong the survival time of animals. And the tumor weight (P<0.05), serum creatinine (P<0.05) and urea nitrogen levels (P<0.01) in TPA combined with CP group were significantly lower than those in CP group. Meanwhile, the results of HE staining showed that the renal tissue damage was significantly reduced in the combined group compared with CP group. The contents of MDA in renal tissue were decreased (P<0.01). However, the contents of GSH and the activity of SOD were increased (P<0.05) in TPA and CP combined group. CONCLUSION: TPA can enhance the inhibitory effect of CP on cell proliferation and inhibit tumor growth in tumor-bearing mice. At the same time, TPA can reduce the renal toxicity of CP, which may be related to the inhibition of renal oxidative stress induced by CP.

Objective:To evaluate the role of CXC chemokine receptor 6 (CXCR6)-mediated activation of natural killer T (NKT) cells in renal fibrosis following acute kidney injury (AKI) in mice.Methods:Eighteen male wild-type C57BL/6 mice and 18 CXCR6 knockout C57BL/6 mice, aged 8-10 weeks, weighing 20-30 g, were divided into 6 groups ( n=6 each) using a random number table method: wild-type mouse control group (group WT-CON), CXCR6 knockout mouse control group (group CXCR6 -/--CON), wild-type mouse with AKI group (group WT-AKI), CXCR6 knockout mouse with AKI group (group CXCR6 -/--AKI), wild-type mouse with AKI + NKT cell adoptive transfer group (group WT-AKI-NKT) and CXCR6 knockout mouse with AKI + NKT cell adoptive transfer group (group CXCR6 -/--AKI-NKT). Folic acid 250 mg/kg was intraperitoneally injected to establish the model of renal fibrosis in mice with AKI.NKT cellsuspension 250 μl(1×10 6 cells) was injected through the tail vein on the 4th and 9th days after folic acid injection in group WT-AKI-NKT and group CXCR6 -/--AKI-NKT, respectively.Blood samples were taken from orbital at day 14 after folic acid injection for determination of the concentrations of serum blood urea nitrogen (BUN) and creatinine (Cr). The animals were sacrificed, and renal tissues were obtained for observation of the area of renal fibrosis (by Sirius red staining) and renal injury (using H&E staining) which was scored and for determination of the proportion of CD1d Tetramer+ cells (by flow cytometry), the number of CD206 and α-smooth muscle actin (α-SMA) double positive (CD206 + -α-SMA + ) cells (by immunofluorescence) and expression of interleukin (IL)-4 and IL-13 mRNA (by real-time polymerase chain reaction). Results:Compared with group WT-CON, the BUN and Cr levels, renal injury scores, area of renal fibrosis, proportion of CD1d Tetramer + cells and CD206 + -α-SMA + cell count were significantly increased, and the expression of IL-4 and IL-13 mRNA was up-regulated in group WT-AKI and WT-AKI-NKT ( P<0.05). Compared with group WT-AKI, the BUN and Cr levels, renal injury scores, area of renal fibrosis, proportion of CD1d Tetramer + cells and CD206 + -α-SMA + cell count were significantly increased, and the expression of IL-4 and IL-13 mRNA was up-regulated in group WT-AKI-NKT ( P<0.05), and the BUN and Cr levels, renal injury scores, area of renal fibrosis, proportion of CD1d Tetramer + cells and CD206 + -α-SMA + cell count were significantly decreased, and the expression of IL-4 and IL-13 mRNA was down-regulated in group CXCR6 -/--AKI ( P<0.05). Compared with group CXCR6 -/--CON, the BUN and Cr levels, renal injury scores, area of renal fibrosis, proportion of CD1d Tetramer + cells and CD206 + -α-SMA + cell count were significantly increased in group CXCR6 -/--AKI and group CXCR6 -/--AKI-NKT ( P<0.05). Compared with group CXCR6 -/--AKI, the BUN and Cr levels, renal injury scores, area of renal fibrosis, proportion of CD1d Tetramer + cells and CD206 + -α-SMA + cell count were significantly increased, and the expression of IL-4 and IL-13 mRNA was up-regulated in group CXCR6 -/--AKI-NKT ( P<0.05). Conclusion:CXCR6-mediated activation of NKT cells is involved in renal fibrosis following AKI in mice, and the mechanism may be related to promoting Th2 cytokine-mediated M2 macrophage-myofibroblast transformation.

Objective:To investigate the effects of PDCA method on improving the accuracy of the Autar Deep Venous Thrombosis (DVT) Scale used by nurses to assess the risk of deep venous thrombosis in surgical patients.Methods:Applied the way of PDCA, namely, raising questions, analyzing reasons, implementing measures, feeding back effects to professional explanate the difficulty in using the scale, moreover, training the nurses used level education method between August 2017 and December2018.The accuracy and consistency of the scale were compared before and after interventions.Results:A total 396 patients were evaluated in the study. There were significant differences in the consistency of evaluation among hospitalized, post-operative and discharged patients after intervention compared with before intervention ( P< 0.0167).The consistency of assessment of team members and responsible nurses increased from 68 to 120 cases, and the consistency of assessment reached 90.91%. The Kappa consistency of assessment of responsible nurses and team members increased from 0.354 before intervention to 0.879 after intervention. The effect was remarkable. Conclusions:PDCA cycle method is based on the problems found in clinical practice. It clarifies the professional terms and rules used in the scale, improves the accuracy and consistency of the Autar DVT scale used by nurses, correctly reflects the risk of thrombosis, ensures the safety of patients, and is worthy of promotion and reference.