Influencing factors of negative conversion time of nucleic acid detection in 228 patients infected with Omicron variant of SARS-CoV-2 in Shanghai / 中国热带医学

@#Abstract: Objective To analyze and compare the effects of different clinical characteristics on the negative conversion time of nucleic acid detection after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant infection, and to provide a scientific basis for the isolation and treatment of coronavirus disease 2019 (COVID-19). Methods　The epidemiological and clinical data of 228 mild SARS-CoV-2 Omicron variant infected patients diagnosed in Shanghai were retrospectively collected from April 27, 2022 to June 8, 2022 in Wujiaochang designated Hospital, Yangpu District, Shanghai. The negative conversion time of nucleic acid detection was used as the outcome variable, and the patients were divided into A (≤18 days) and B (>18 days). Univariate and multivariate logistic regression analysis were used to analyze the influencing factors of the negative conversion time of nucleic acid detection. Results　The mean nucleic acid conversion time of 228 patients was (18.7±12.1) d, with the median time of 18 (2-46) d. Among them, 120 patients in group A had an average nucleic acid conversion time of (13.2±2.0) d, and 108 cases in group B had an average nucleic acid conversion time of (20.8±1.3) d. Univariate analysis showed that there were no statistically significant differences in the effects of hypertension, coronary heart disease, diabetes, hypokalemia, malignant tumors, neuropsychiatric diseases, chronic digestive diseases on the negative nucleic acid conversion time (P>0.05); however, there were significant differences in the effects of combined cerebrovascular disease, leukopenia, chronic respiratory system diseases and vaccination on the negative nucleic acid conversion time (P<0.05). Further multivariate logistic regression analysis revealed that the combination of chronic respiratory diseases and non-vaccination were significant risk factors for prolongation of negative nucleic acid conversion time (P<0.05). Conclusions The results of this study show that gender, age and whether hypertension, coronary heart disease, diabetes mellitus, hypokalemia, malignant tumor, neuropsychiatric disease and chronic digestive disease have no significant effect on the nucleic acid conversion time, whereas chronic respiratory disease and no vaccination are significantly correlated with the prolongation of nucleic acid conversion time in SARS-CoV-2 Omicron-infected patients.

Promising Therapeutic Functions of Bone Marrow Mesenchymal Stem Cells Derived-Exosome in Asthma.

Asthma is a chronic inflammatory disturbance of the airways in which many cells and cellular elements are involved. Wheezing, breathlessness, chest tightness, and coughing, especially at night or in the early morning, are typical symptoms of asthma. At present, inhaled corticosteroid (ICS) and long-acting ß-agonists (LABAs) are standard treatments for regular management. Oral corticosteroids (OCSs) were recommended for controlling asthma exacerbation but only for a short-term treatment because of the side effects on organs. Biologic therapies have achieved exciting and notable effects in clinical treatment but are not applicable for all phenotypes of asthma. At present, some new approaches are under exploration to lessen side effects and improve curative effects. Studies have revealed that bone marrow mesenchymal stem cells (BMMSCs) hold various curative effects in asthma and may benefit in the long term with high safety. Extracellular vesicles (EVs) enriched in body fluid were characterized as subcomponents of extracellular vesicles and delivered carriers combined with genetic messages in vivo. The therapeutic potential of exosomes has become a research hotspot in many diseases. BMMSC-derived exosomes were considered as the dominant part of BMMSCs in cell-to-cell communications and playing curative effects. Points also hold that BMMSC-Exo could interfere with airway inflammation and airway remolding in asthma via modulating the immune response, regulating gene expression, adjusting the phenotype of macrophage, etc. However, BMMSC-Exo still lacked more clinical trials for evaluating the effects on asthma, and the technology of extraction and purification still needs to be improved for wide use. This review aims to draw the relationship among asthma, BMMSC, and exosome, which may provide innovate ideas for treatment of asthma, and arouse attention about the curative potential of BMMSC-Exo.

Research progress on icariin, a traditional Chinese medicine extract, in the treatment of asthma.

Bronchial asthma is a common chronic airway disease, and long-term management of asthma is the focus and challenge of clinical treatment. Glucocorticoids are often used as the first choice for the treatment of asthma. However, the occurrence of hormone dependence, hormone resistance, and local and systemic adverse reactions caused by hormone application also creates problems for the treatment of asthma. Finding new, safe, and effective therapeutic drugs is an important research direction at present. Icariin is an effective ingredient of the traditional Chinese medicine, Epimedium. It has various biological attributes such as anti-inflammatory and antioxidative activities, and immune regulation. It has high safety and a wide range of clinical applications. Icariin has the characteristics of multitargeted intervention in the treatment of asthma. Here, we review the specific mechanisms of icariin in treating asthma, and icariin is considered a novel therapy in controlling asthma; however, the mechanism is still worth further investigation.

Optimization modeling of single-chain antibody against hepatoma based on similarity algorithm.

The purposes was to establish optimal modeling of single-chain antibody molecules based on similarity algorithm and seek the connecting peptides that had the minimal effect on the structure and bioactivity of the variable region of heavy chain (VH) and that of light chain (VL) in a single-chain antibody against liver cancer. After the Linker with different lengths (n=0~7) had been added into single chain fragment variable (ScFv), modeling of the overall sequences of VH, VL and ScFv were conducted respectively. Meanwhile, the peptide chain structure of (Gly4Ser)n was adopted for the connecting peptide. Then the spatial spherical shell layer alignment algorithm based on spherical polar coordinates was utilized for comparing the structural similarity of VH and VL before and after adding connecting peptide. Equally, in order to determine the stability of VH and VL, MATLAB was applied for analysis of the fore and aft distances and the diffusion radius. Indirect ELISA method was used to detect single-chain antibody immunological activity of Linker with different lengths. The MTT assay was utilized for the examination of the inhibition rate of single-chain antibody with different lengths of Linker to liver cancer cell. When n=4, the structural similarity between VH together with VL and their original ones was the highest. When n=3, the influence of connecting peptide on the stability of VH and VL was minimum. When n>3, the fore and aft distances changed little due to the increase and fold of the length of peptide chain. The results of ELISA detection showed that when n=4, affinity of single chain antibody to liver cancer cells was much higher. The MTT test also indicated that when n=4, the inhibition rate of the connecting peptide on hepatoma carcinoma cell reached the highest, and that came second when n=3. When n=4, the structural stability and biological functions of anti-hepatoma single-chain antibody were both favorable. This study has provided a basis for the design and construction of single-chain antibody.

Ultrasonic diagnosis and vasoactive substances examination in patients with cirrhosis.

OBJECTIVE: To investigate hemodynamic change of patients with cirrhosis by using Color Doppler ultrasound technique and to explore the significance of change in the content of vasoactive substances-plasma endothelin-1 (ET-1) and calcitonin gene-related peptide (CGRP). METHODS: A total of 178 cases with cirrhosis were regarded as study groups, and were divided into three degrees: A, B and C according to child-pugh and meanwhile 60 cases were regarded as normal control group. Portal vein and splenic vein of patients were explored by adopting Color Doppler ultrasound technique, related indexes were recorded and the blood flow as well as their ration in the two groups was calculated. Radio immunoassay was adopted to detect the content of plasma ET-1 and CGRP in both study group and contrast group. RESULTS: Compared with the healthy cases in the contrast group, there was abnormal hemodynamics in the system of portal vein of patients with cirrhosis and the content of plasma ET-1 and CGRP was increased obviously. In the Child-Pugh liver function grades, the content of ET-1 and CGRP was increased as the degree of cirrhosis became more and more serious. There was no significant difference in the comparison between those without ascites and those in contrast group (P>0.05), the content of plasma ET-1 and CGRP in patients without ascites was increased remarkably. Besides, there was positive correlation between the content of plasma ET-1 and CGRP and Dpv, Dsv and Qsv. CONCLUSION: Detection of abnormal hemodynamics of portal vein and splenic vein by Color Doppler ultrasound technique can be one of the means for diagnosis of hypertension. Plasma ET-1 and CGRP of patients with cirrhosis reflect the serious degree of the damage in live function and play an important role in the formation and development of portal hypertension.

Effect of Chinese herbal compound on liver fibrosis in rabbits with schistosomiasis by B-ultrasound.

OBJECTIVE: To explore the value of B-ultrasound on the evaluation of the effects of traditional Chinese medicine compound of Radix astragali, Salvia miltiorrhiza and Angelica sinensis, and TCM + praziquantel on liver fibrosis in rabbits with schistosomiasis. METHODS: The hepatic fibrosis model in rabbits with schistosomiasis was established. The experimental animals (24 rabbits) were randomly divided into four groups (group A, B, C and D, n=6). Group A (control group) was only treated by praziquantel; Group B was treated by mixture of Radix astragali and Salvia miltiorrhiza + praziquantel; Group C was treated by mixture of Radix astragali and Angelica sinensis + praziquantel; Group D was treated by mixture of Radix astragali, Salvia miltiorrhiza and Angelica sinensis + praziquantel. Then B-ultrasonogram was used to evaluate the effects. RESULTS: Each group showed certain curative effect on liver fibrosis in rabbits with schistosomiasis. The efficacy of group B, C and D was better than group A, and that of group D was the best. The differences in long diameter, thickness diameter, transverse diameter and portal vein inner diameter of liver before and after treatment were statistically significant (P<0.05). The liver function indexes and liver fibrosis indexes were significantly improved after treatment (P<0.05). CONCLUSIONS: The mixture of Radix astragali, Salvia miltiorrhiza and Angelica sinensis combined with Western medicine treatment can obviously improve the efficacy on liver fibrosis of schistosomiasis.

Efficacy and safety of alcohol sclerotherapy involving single-session multiple injections to treat simple renal cysts: a multicenter, prospective, randomized, controlled trial.

BACKGROUND: Alcohol has been used for treating simple renal cysts since 1981. Since then, various observational studies have examined the technique, but they differ significantly in the details of the procedures and efficacy measures used. This has made it difficult to assess the safety and efficacy of this technique. We carried out a randomized controlled trial to evaluate the efficacy and safety of ultrasound-guided alcohol sclerotherapy involving single-session multiple injections to treat simple renal cysts. METHODS: A total of 144 patients with simple renal cysts were randomly allocated to either the treatment group (ultrasound-guided percutaneous drainage and alcohol sclerotherapy with single-session multiple injections) or control group (ultrasound-guided simple percutaneous drainage). Follow-up CT scans of ablated cysts were collected 3 and 6 months after the procedure. The outcome was considered successful if cyst volume between baseline and 6 months decreased by at least 87.5%. RESULTS: Intention-to-treat analysis revealed an average volume reduction of 94.2% in the treatment group and 50.8% in the control group (P < 0.0001). The percentage of patients achieving successful outcomes was 88.9% (95%CI 77.0% - 100.0%) in the treatment group and 22.2% (95%CI 6.54% - 37.9%) in the control group (P < 0.0001). The corresponding results in the per-protocol analysis were an average volume reduction of 96.4% in the treatment group and 50.8% in the control group (P < 0.0001). The percentage of patients achieving a successful outcome was 94.3% (95%CI 85.6% - 100.0%) in the treatment group and 22.2% (95%CI 6.54% - 37.9%) in the control group (P < 0.0001). CONCLUSION: Alcohol sclerotherapy involving single-session multiple injections is safe and efficacious in the treatment of renal cysts.

[Predicting prostate cancers using a logistic regression model with transrectal ultrasound characteristics, age and serum PSA].

OBJECTIVE: To determine the value of transrectal ultrasound characteristics in combination with age and prostate specific antigen (PSA) for predicting prostate cancers. METHODS: 579 patients with prostate diseases were examined with color doppler, followed by biopsies of prostates. A logistic regression model was developed to determine the relationship between prostate cancers and transrectal ultrasound characteristics, age and PSA levels. RESULTS: The biopsy confirmed 194 (33. 5%) prostate cancer cases and 385 (66. 5%) noncancerous patients with prostate diseases. The prostate cancer patients showed hypoechoic nodule, uneven echo, abnormal blood flow, abnormal prostate shape, unclear boundary of internal and external glands, unclear dividing line of prostate and seminal vesicle glands, unclear dividing line of prostate and rectal, and lymph node metastasis. Our prediction model had a 83.59% accuracy, 64.95% sensitivity, 92.99% specificity, 82.35% positive predictive value, and 84.04% negative predictive value. CONCLUSION: Transrectal ultrasound characteristics in combination with patients age and serum PSA is a good predictor of prostate cancer.

Application of ultrasound contrast in identification and diagnosis of ocular spaceoccupying lesions.

AIM: To analyze the application significance of ultrasound contrast agent in identification and diagnosis of ocular spaceoccupying lesions, and mainly analyze its advantages and problems. METHODS: Thirty-two representative literatures about the application of ultrasound contrast agent in diagnosis of spaceoccupying lesions at home and abroad were collected after focused on sorting the literature reporting the application of ultrasound contrast diagnostic technology in the diagnosis and identification of ocular spaceoccupying lesions in recent years. Its advantages and problems were retrospectively analyzed, and reasonable assessment on existing problems was made and possible solutions to the problems were proposed. RESULTS: As a new imaging diagnostic technique, the contrast-enhanced ultrasound, which can enhance the display of tumor microcirculation vessels and improve the tumor's ultrasound diagnostic capability, was analyzed. Through sorting and comprehensively analyzing the collected literatures, the positive rate of ocular spaceoccupying lesion diagnosis could be significantly improved with ultrasound contrast technology. Thus, the vascular perfusion in normal tissues and lesions was reflected objectively. According to the lesion's perfusion characteristics of the contrast agent plus with the performance features of two-dimensional ultrasound, the ocular spaceoccupying lesions can be accurately diagnosed, and this could provide clinicians with reliable research basis in this field. CONCLUSION: Ultrasound contrast examination is a new testing method, and ultrasound contrast agent can significantly enhance the ultrasonic detection signal, clearly show the blood perfusion in vessels and tissues, increase the image contrast resolution, and improve the lesion's detection capability in the microcirculation perfusion level, especially its important value in the diagnosis of ocular tumor.

Application of ultrasound microbubble contrast technology in ophthalmic targeted therapy: literature analysis.

AIM: To analyze the application of microbubble contrast technology in the treatment of ophthalmic diseases, mainly analyzing its advantages and existing problems. METHODS: A total of 30 representative literatures about the application of ultrasound contrast agent in gene targeted therapy at home and abroad were collected, and focusing on sorting out the literature reporting the treatment of ophthalmic diseases with microbubble contrast technology in recent years, then recalling its advantages and problems, finally making reasonable assessment on existing problems and proposing possible solutions to the problems. RESULTS: DUE TO ITS UNIQUE SAFETY AND EFFICACY, THE TREATMENT OF OPHTHALMIC DISEASES WITH MICROBUBBLE CONTRAST TECHNOLOGY HAS INCREASINGLY DRAWN THE ATTENTION OF CLINICIANS, BUT TWO RELEVANT ISSUES SHOULD BE CONSIDERED: first, the nature of contrast agent and the choice of corresponding ultrasound parameters; second, relative incidence of tissue bleeding, intravascular hemolysis, moderate or severe allergy as well as other side effects. CONCLUSION: Microbubble may become the carrier of targeted therapy, and as a kind of new non-invasive delivery system, the ultrasound contrast agent has broad application prospects, but its application in ophthalmic research is still in its initial stage and the safety of contrast-enhanced ultrasound still needs further study.

[In vivo transfer of human chemokine-like factor 1 gene increases peripheral blood CD34+ stem cells after myocardial infarction in rats].

OBJECTIVE: To assess the influence of different doses of CKLF1 plasmid on the dynamics and magnitude of the mobilization of the mobilization bone of marrow stem cells in a rat AMI model. METHODS: Different doses of plasmid DNA encoding CKLF1 gene, empty plasmid or saline were injected into male SD rats intramuscularly with in vivo electroporation. Rats were subjected to left coronary artery ligation 6 days after gene transfer. Peripheral blood samples were drawn and CD34+ cells were assayed by FACS calibur flow-cytometer. The changes in absolute number of CD34+ cells were evaluated. RESULTS: Expressions of CKLF1 mRNA and protein were detected in the injection site 7 days after gene transfer. Five days after gene transfer, the CD34+ cells numbers in CKLF1 groups were significantly higher than those in empty plasmid group, especially in CKLF1 100 microg group (16.63x10(6)/L vs 4.98x10(6)/L, P<0.01). On the 5-7 days, the CD34+ cell numbers in CKLF1 groups reached the peak and the peak number was 3.88 times that of baseline in CKLF1 100 microg group (P<0.01). After AMI, the cell numbers of 1 day to 7 days were significantly higher than those of the baseline in empty plasmid group and saline group. In comparison to empty plasmid group, CKLF1 groups were associated with still higher numbers of cells 1 day after AMI (P< 0.05), especially in CKLF1 100 microg group (14.61x10(6)/L vs 7.85x10(6)/L, P<0.01). CONCLUSION: CKLF1 gene transfer significantly increases the mobilization of CD34+ stem cells in acute myocardial infarction rats.

[A new method for the detection of platelet derived microparticles by cytometric bead array and its evaluation].

OBJECTIVE: To establish a new method for the detection of platelet derived microparticles (PMPs) by cytometric bead array and to evaluate the characteristic of this method. METHODS: Using detection beads coated with monoclonal antibody against platelet glycoprotein IIIa to capture PMPs, then using CD41 PE to react with PMPs captured by detection beads, finally using flow cytometer detect beads-PMPs-CD41 PE complex. Anticoagulant, reaction time and other condition were optimized. Then reproducibility and linear range of this method were evaluated. PMPs of 45 health adults were determined by this method. RESULTS: Detection beads were stable in 4 degrees C for over 90 days (coefficient of variance was 0.65%) which matched the basic request of clinical detection. CTAD could restrain the in vitro release of PMPs efficiently; The reaction could reach maximum combination at room temperature after 4 hour; Non-specific absorbance of detection beads could be eliminated by washing of PBS. This method had preferable reproducibility (CV in batch was 6.8%; CV between batch was 10.4%) and a wide linear range from 0 to 200 microl of platelet activation suspension (r = 0.9962). PMP level of 45 health adults was 1.031-1.766. CONCLUSION: PMPs can be detected exactly by cytometric bead array, and it's important for PMPs detection to be an assistant for diagnosis of haemorrhagic and thrombotic diseases.

[Incidence of deep venous thrombosis (DVT) in patients undergoing thoracotomy and changes of hemostasis].

OBJECTIVE: To survey the incidence of deep venous thrombosis (DVT) in high risk patients undergoing thoracotomy and observe the changes of hemostatic activity. METHODS: Fifty-two consecutive patients (ages that ranged from 35 to 79, 34 men and 18 women) with lung or esophagus cancer were enrolled into this prospective trial. The patients included underwent major thoracic surgery from February 2003 to April 2003. Bilateral lower extremity duplex ultrasonography for DVT screening was performed 3-10 days post surgery in all 52 patients and 57 matched clinic normal controls. Venous blood was collected to determine fibrinogen (FIB), D-dimer(D-D), plasminogen activator inhibitor (PAI), antithrombin (AT)i thrombin antithrombin complex (TAT), prothrombin time (PT), international normalized ratio (INR), and activated partial thromboplastin time (APTT) immediately before surgery, the third and tenth days postoperatively. No patient had a prior thromboembotic history. Risk factors for DVT were evaluated. RESULTS: Of the 52 patients, 28 (53.8%) had an acute postoperative DVT detected in the calf. One patient died of suspected pulmonary embolism postoperatively. Plasma levels of FIB and D-D increased significantly up to 7 d after operation. AT level decreased significantly 3 d after operation and returned to normal 7 d latter. TAT increased significantly 3 d post operation and decreased to normal on day 7. PAI level was lowered 3 d after surgery, but increased significantly on day 7 compared with that on day 3. With the addition of risk factors related to thrombosis, the incidence of DVT was increased correspondingly. CONCLUSION: Of the patients undergoing major thoracic surgery,53.8% of them had a postoperative DVT by postoperative screening duplex ultrasound. In Chinese population, incidence of DVT appears to be high without prophylaxis, which is similar to other reports of westerners. These patients had a number of risk factors for the development of DVT, which include older age, overweight, hypertension, diabetes, and history of thromboembolism, etc. Prophylactic measures should be taken against postoperative venous thromboembolism in major thoracic surgery with high risk, including early mobilization, anticoagulant therapy with heparins, and intermittent pneumatic compression (IPC).

Construction and identification of recombinant vectors carrying herpes simplex virus thymidine kinase and cytokine genes expressed in gastric carcinoma cell line SGC7901.

AIM: To construct and identify the recombinant vectors carrying herpes simplex virus thymidine kinase (HSV-TK) and tumor necrosis factor alpha (TNF-alpha) or interleukin-2 (IL-2) genes expressed in gastric carcinoma cell line SGC7901. METHODS: The fragments of HSV-TK, internal ribosome entry sites (IRES) and TNF-alpha or IL-2 genes were inserted in a TK-IRES-TNF-alpha or TK-IRES-IL-2 order into pEGFP-N(3) and pLXSN to generate the therapeutic vectors pEGFP-TT, pEGFP-TI, pL(TT)SN and pL(TI)SN respectively, which were structurally confirmed by the digestion analysis of restriction endonuclease. The former two plasmids were used for the transient expression of recombinant proteins in the target cells while pL(TT)SN and pL(TI)SN were transfected into SGC7901 cells by lipofectamine for the stable expression of objective genes through G418 selection. The protein products expressed transiently and stably in SGC7901 cells by the constructed vectors were confirmed by fluorescent microscopy and Western blot respectively. RESULTS: The inserted fragments in all constructed plasmids were structurally confirmed to be consistent with that of the published data. In the transient expression, both pEGFP-TT and pEGFP-TI were shown expressed in nearly 50% of the transfected SGC7901 cells. Similarly, the G418 selected vectors PL(TT)SN and PL(TI)SN were confirmed to be successful in the stable expression of the objective proteins in the target cells. CONCLUSION: The constructed recombinant vectors in the present study that can express the suicide gene TK in combination with cytokines genes may serve as the potential tools to perform more effective investigations in future for the gene therapy of gastric carcinoma.

Do there exist synergistic antitumor effects by coexpression of herpes simplex virus thymidine kinase with cytokine genes on human gastric cancer cell line SGC7901?

AIM: To evaluate the synergistic antitumor effects of herpes simplex virus thymidine kinase (HSV-TK) together with tumor necrosis factor alpha (TNF-alpha) or interleukin-2 (IL-2) gene expression on gastric cancer cell line SGC7901. METHODS: Recombinant vectors pL(TT)SN and pL(TI)SN, which express TK-IRES-TNF-alpha and TK-IRES-IL-2 genes separately, as well as the control plasmids pL(TK)SN and pLXSN were employed to transfect PA317 cells respectively to generate the viruses that can stably express the objective genes through G418 selection. The gastric cancer cells were then transfected by the retroviral serum from the package cells and maintained in culture to determine the cell growth and apoptosis. The cytotoxic effects of HSV-TK together with TNF-alpha or IL-2 gene expression on the transfected cancer cells were evaluated by the cell viability and bystander effects in the presence of GCV supplemented in the cultural medium. RESULTS: Expression of recombinant proteins including TNF-alpha and IL-2 by stable transfectants was confirmed by Western blotting. The percentage of cell apoptosis in the SGC/0, SGC/TK-TNF-alpha, SGC/TK-IL-2 and SGC/TK clone was 2.3%, 12.3%, 11.1% and 10.9% respectively at 24 h post-transfection. Cell growth status among all the experimental groups as judged by cell absorbance (A) at 570nm did not exhibit any significant difference (P>0.05); although it was noted to be slightly lower in the SGC/TT group. Cell survival rate in SGC/TI, SGC/TT and SGC/TK group was significantly decreased in a dose-dependent manner of GCV compared with that of the SGC/0 group (P<0.05-0.01). Among all studied cells, the SGC/TT was shown most sensitive to GCV with a half lethal dose of 0.5 mg/L(-1). In contrast, the survival rate of SGC/0 cells was not affected by the presence of GCV with the doses less than 10 mg/L(-1). The half lethal dose of GCV for SGC/0 cells was more than 100 mg/L(-1). Marked bystander effect induced by SGC/TI, SGC/TT and SGC/TK cells was confirmed by the fact that 20% of these stable transfectants could kill 50% of the co-cultured cells, in which the most prominent bystander effect was found in the circumstance of SGC/TT presence. However, no significant difference of these variables was found among SGC/TI, SGC/TT and SGC/TK cells (P>0.05). CONCLUSION: The synergistic antitumor effects produced by the co-expression of HSV-TK with TNF-alpha or IL-2 genes were not present in the transfected SGC7901 cells. The mechanism underlying these phenomena was not known.

[Reversal effect of berbamine on multidrug resistance of K562/A02 cells and its mechanism].

This preject is to explore the reversal efficacy of calmodulin antagonist berbamine (BBM) on multidrug resistance (MDR) and its mechanism. Human erythroleukemic cell line K562 and its adriamycin-resistant counterpart K562/A02 were used in the study. The cells were co-cultured with ADR and BBM in different concentrations. MTT assay was used to analyze the effect of BBM on cell growth inhibition. According to the MTT assay, the 50% inhibitory concentration (IC(50)), the multiples of drug resistance and increased sensitivity of ADR were calculated. The concentration of intracellular ADR and expression level of P-gp were detected by flow cytometry (FCM). The expression level of mdr1 mRNA and survivin mRNA was detected by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) with beta-actin as internal reference. The results showed that IC(50) of ADR in K562 and K562/A02 cells was 1.16 +/- 0.09 micro mol/L and 37.47 +/- 1.76 micro mol/L, respectively. The resistant multiple of K562/A02 cells to ADR was 32.30 higher than that of K562 cells. BBM increased the chemo-sensitivity of ADR in K562/A02 cells with dose-dependent relationship, i.e. when 5, 10 and 20 micro mol/L BBM was added in the culture the chemo-sensitivity of ADR was increased to 2.01-, 9.68-, and 41.18-fold (P < 0.01), respectively. After treating K562/A02 cells by 5 or 10 micro mol/L BBM for 2 hours the accumulation of intracellular ADR was increased to 1.41- and 1.52-fold (P < 0.01), respectively. Treating by BBM for 72 hours decreased 4.12% (P < 0.05) and 27.09% (P < 0.01) of P-gp expression, respectively, meanwhile down-regulated expression of mdr1 mRNA and survivin mRNA was found. In conclusion, BBM could increase intracellular concentration of ADR in K562/A02 that down-regulated expression level of mdr1 mRNA and P-gp and survivin so that the sensitivity of K562/A02 to ADR was increased significantly.