[Long-term high-fat diet's impact on synaptic plasticity in the visual cortex and hippocampus neurons: an experimental study]

Objective: To investigate the effects and mechanisms of long-term high-fat diet on synaptic plasticity in the visual cortex and hippocampus neurons of juvenile mice. Methods: This was an experimental study. Twenty-four 4-week-old male C57BL/6J mice were randomly divided into two groups, using a randomized numerical table, with 12 mice in each group. The ND group was fed a normal diet, while the HFD group was fed a high-fat diet. After 12 weeks of feeding, mouse body weight, body fat percentage, glucose tolerance, and blood lipid levels were recorded. Six mice from each group were randomly selected using a randomized numerical table, and long-term potentiation (LTP) in the lateral geniculate nucleus (LGN)-primary visual cortex binocular zone (V1B area) and hippocampus CA3-CA1 were recorded in vitro. Field excitatory postsynaptic potentials (fEPSPs) were measured, and the normalized fEPSP slope was calculated to evaluate changes in cortical synaptic plasticity. Subsequently, brain tissue was collected for Golgi staining to observe the development of pyramidal neurons in layers Ⅱ-Ⅲ of the primary visual cortex and CA1 region of the hippocampus, and changes in dendritic spine morphology and quantity were compared. The remaining six mice from each group were euthanized, and brain tissue was collected for transmission electron microscopy to observe ultrastructural changes in the visual cortex V1B area and hippocampus CA1 region neurons. Independent samples t-test was used for statistical analysis. Results: After 12 weeks of feeding, the body weight of mice in the HFD group was (29.17±1.63) g, significantly lower than the ND group which was (37.99±6.87) g (t=4.33, P<0.001). The body fat percentage in the HFD group was 1.09%±0.22%, which was higher than the ND group with 0.85%±0.09% (t=2.50, P=0.032). HFD mice showed a significant increase in blood glucose level 30 minutes after glucose injection, reaching (17.80±3.94) mmol/L, compared to the ND group with (23.10±1.48) mmol/L (t=3.07, P=0.013). At 60 minutes after glucose injection, the difference in blood glucose levels between the ND group [(13.58±2.39) mmol/L] and the HFD group [(23.70±3.56) mmol/L] was statistically significant (t=5.40, P<0.001). Subsequently, both groups showed a decline in blood glucose levels, and at 120 minutes after glucose injection, the blood glucose level in the ND group decreased to (8.50±1.05) mmol/L, while the HFD group remained at a higher level of (16.03±4.17) mmol/L, showing a statistically significant difference (t=3.91, P=0.004). The serum total cholesterol levels in the ND and HFD groups were (4.08±0.35) mmol/L and (10.80±0.90) mmol/L, respectively, with the HFD group higher than the ND group (t=15.23, P<0.001). However, there was no significant difference in triglyceride levels (P>0.05). The high-density lipoprotein cholesterol level in the ND group was (2.12±0.57) mmol/L, while in the HFD group, it was (1.28±0.15) mmol/L, with the HFD group lower than the ND group (t=3.15, P=0.014). Non-high-density lipoprotein cholesterol level in the HFD group was (11.06±1.46) mmol/L, significantly higher than the ND group with (2.28±0.43) mmol/L (t=12.88, P<0.001). In the hippocampal CA3-CA1 pathway, the fEPSP slope increased by 239.1%±88.8% of baseline in the ND group, while in the HFD group, it was only 147.6%±31.6% of baseline, indicating lower LTP compared to the ND group (t=7.20, P<0.001). For the LGN-V1 pathway, the fEPSP slope increased by 204.8%±67.0% of baseline in the ND group, while in the HFD group, it was 121.1%±15.7% of baseline, showing reduced LTP compared to the ND group (t=9.11, P<0.001). Regarding the visual cortex, in the V1B area of the ND group, the number of dendritic spines per 10 μm was (1.31±1.14), while in the HFD group, it was (0.77±0.43), demonstrating a significant decrease in dendritic spine density (t=3.45, P<0.001). The proportion of mature dendritic spines in the ND group was 69.98%, while non-mature dendritic spines accounted for 30.02%. In contrast, the HFD group had 45.76% mature dendritic spines and 54.24% non-mature dendritic spines. Regarding changes in hippocampal CA1 pyramidal neurons, the cell bodies and axons were not damaged, but HFD group neurons exhibited simplified dendritic structures with reduced branching. The number of dendritic spines per 10 μm was (10.25±3.84) in the HFD group and (25.22±8.21) in the ND group, indicating significantly lower dendritic spine density in the HFD group (t=12.42, P<0.001). The proportion of mature dendritic spines in the ND group was 70.88%, while non-mature dendritic spines accounted for 29.12%. In contrast, the HFD group had 47.37% mature dendritic spines and 52.63% non-mature dendritic spines. Moreover, the ultrastructure of neurons in the visual cortex V1B area and hippocampus CA1 region of HFD mice showed evident damage, with disrupted cell structures, swollen and vacuolated mitochondria, reduced or even disappeared mitochondrial cristae, and decreased synaptic quantity with damaged structure. Conclusions: Long-term high-fat diet in juvenile mice leads to abnormal development and functional maturation of synapses in the visual cortex and hippocampal regions. Dendrites, as the foundation of synaptic structures, undergo abnormal development, which can cause alterations in synaptic plasticity of related neural circuits.

[C-reactive protein is associated with impaired working capacity in Chinese patients with ankylosing spondylitis in paid employment: the real-world evidence from Smart-phone SpondyloArthritis Management System]

To investigate the relationship between serum C-reactive protein (CRP) levels and work impairment in patients with ankylosing spondylitis (AS) based on real-world evidence. Outpatients with confirmed AS at Chinese PLA General Hospital were recruited consecutively by Smart-phone SpondyloArthritis Management System (SpAMS) from April 2016 to April 2018. The relationship between CRP and work productivity and activity impairment questionnaire (WPAI) were evaluated. Five hundred and fifty-one outpatients with AS in paid employment were recruited. The presenteeism, overall work impairment, and activity impairment rates increased by 1.4% (1.1%, 1.8%), 1.1% (0.5%, 1.6%), and 1.7% (1.3%, 2.1%), respectively, for every 10 mg/L increase in the CRP level (all P value<0.01). However, the CRP level was not associated with absenteeism after adjusting for covariates [0.5%(-0.4%, 1.0%),P>0.05]. There is a significant association between increased serum CRP levels at baseline and the previous 7-day work impairment in patients with AS. Higher CRP levels contribute to worse presenteeism, overall work impairment, and activity impairment rates, which suggests the necessity of monitoring CRP on treatment, and also indicates that anti-inflammatory therapy may be effective for improving work productivity.

Timing of continuous renal replacement therapy in severe acute kidney injury patients with fluid overload: A retrospective cohort study

PURPOSE

We aimed to evaluate the association of early versus late initiation of Continuous renal replacement therapy (CRRT) with mortality in patients with fluid overload.

METHODS

This was a retrospective cohort study of patients with fluid overload (FO) treated with CRRT due to severe acute kidney injury (AKI) between January 2015 and December 2017 in a mixed medical intensive care unit of a teaching hospital in Beijing, China. Patients were divided into early (≤15 h) and late (>15 h) groups based on the median time from ICU admission to CRRT initiation. The primary outcome was all-cause mortality at day 60. Multivariable Cox model analysis was used for analysis.

RESULTS

The study patients were male predominant (84/150) with a mean age of 64.8 ± 16.7 years. The median FO value before CRRT initiation was 10.1% [6.2-16.1%]. The 60-day mortality rates in the early vs the late CRRT groups were 53.9% and 73%, respectively. On multivariable Cox modelling, the late initiation of CRRT was independently associated with an increased risk of death at 60 days (HR 1.75, 95% CI 1.11-2.74, p = 0.015).

CONCLUSIONS

Early initiation of CRRT was independently associated with survival benefits in severe AKI patients with fluid overload.

MRI findings of central nervous system involvement in children with haemophagocytic lymphohistiocytosis: correlation with clinical biochemical tests

AIM

To investigate the brain magnetic resonance imaging (MRI) features of children with haemophagocytic lymphohistiocytosis (HLH) with central nervous system (CNS) involvement, and to investigate the correlation with clinical biochemical tests.

MATERIAL AND METHODS

Clinical and MRI data were collected from 118 children with HLH-CNS between January 2012 and June 2019. Patients were grouped according to their MRI findings, and statistical methods were used to test for correlations between the MRI findings and biochemical variables.

RESULTS

Patients were divided into three groups, including normal appearance (Group 1, 17/118), diffuse parenchymal volume loss (Group 2, 44/118), and brain parenchyma lesions (Group 3, 57/118) containing three subtypes of brain lesions and HLH-CNS complications. Comparing biochemical values among the three groups revealed a significant difference for all values (p<0.05), except for cell counts in the cerebrospinal fluid (CSF). A pairwise comparison further showed significant inter-group differences for most of the variables. Spearman's rank correlation coefficient also demonstrated that CSF cell counts (r=0.193, p=0.036), CSF microprotein content (r=0.379, p<0.001), serum aspartate aminotransferase (AST; r=0.521, p<0.001), serum lactate dehydrogenase (LDH; r=0.514, p<0.001) and activated partial thromboplastin time (APTT; r=0.326, p<0.001) correlated positively with the MRI groups, while platelet count (PLT; r=-0.633, p<0.001) and plasma fibrinogen (FIB; r=-0.258, p=0.005) correlated negatively.

CONCLUSION

Classification of brain MRI findings of HLH-CNS correlates well with the results of several key biochemical tests. Brain MRI is a promising method to elucidate illness severity and clinical outcomes.

[Clinical characteristics of patients with ankylosing spondylitis and inflammatory bowel disease]

Objective: To analyze the clinical characteristics of patients with ankylosing spondylitis (AS) with inflammation bowel disease (IBD). Methods: AS patients fulfilling the 1984 modified New York diagnostic criteria were recruited in Chinese AS Prospective Imaging Cohort (CASPIC) consecutively from April 2016 to June 2017 in Chinese People's Liberation Army General Hospital by using smart management system for spondyloarthritis (SpAMS). The diagnosis of IBD was confirmed by tissue pathology via ileocolonoscopy. Demographic, clinical and biochemical data were collected. Results: In total, 893 patients with AS were recruited with the mean age 30.8 years. The majority were men (739, 82.8%). There were 64 (7.2%) patients concomitant with IBD. The mean age [(34.5±7.5) years vs. (30.5±8.8) years, P<0.001] was older and the disease duration [(10.8±6.9) years vs. (8.1±5.9) years, P=0.001] was longer in patients with IBD than patients without. Compared with patients without IBD, patients with IBD had more frequent involvement of the cervical spine [(21.9% (14/64) vs. 10.5% (87/829), P=0.006) and thoracic spine [29.7% (19/64) vs. 12.3% (102/829), P<0.001]. Uveitis [28.1% (18/64) vs. 16.4% (136/829), P=0.017] and psoriasis [7.8% (5/64) vs. 2.3% (19/829), P=0.009] were also more common in patients concomitant with IBD. In addition, patients with IBD had significantly higher scores in BASDAI (3.3±2.1 vs. 2.4±1.8, P<0.001), BASFI [2.2 (1.0,3.3) vs. 1.1(0.2,2.4), P<0.001)] and ASAS HI (7.1±4.3 vs. 5.3±3.7, P= 0.001) than patients without IBD. Conclusions: Compared with patients without IBD, AS patients concomitant with IBD have more severe disease activity and organ dysfunction. Furthermore, the uveitis and psoriasis are more frequently accompanied in AS patients with IBD.

[The effect of arthroscopic synovectomy on refractory knee arthritis with popliteal cyst in 153 patients]

Objective: To investigate the efficacy of arthroscopic synovectomy on refractory knee arthritis complicated with popliteal cyst. Methods: Patients diagnosed as rheumatoid arthritis (RA) or spondyloarthritis (SpA) with refractory knee arthritis who underwent knee arthroscopic synovectomy in our hospital from 2010 to 2017 were enrolled, including 20 patients (16 RA, 4 SpA) with popliteal cyst. Clinical data, RA disease activity score (DAS28), SpA back pain score, etc, were collected to evaluate the efficacy of knee surgery. Results: Erythrocyte sedimentation rate (ESR) [58(17, 79)mm/1h vs. 19(9, 30)mm/1h, P< 0.001],C reactive protein (CRP) [3.72(0.92,8.14) mg/L vs. 0.85(0.10,3.08) mg/L,P<0.001], rheumatoid factor [64.6(20.2,193.3) vs. 20.5(10.0,58.4),P<0.001], DAS28 score(4.67±1.25 vs. 2.81±1.23,P<0.001), knee joint discomfort score [5(4,6) vs. 2(1,3),P<0.001] and the volume of knee joint effusion by ultrasound (P<0.05) in 95 RA patients were significantly decreased compared to those before operation. ESR [27(12,54)mm/1h vs. 20 (16,28) mm/1 h,P<0.001], CRP [3.27(1.06,6.95) mg/L vs. 1.41(0.34,3.03)mg/L,P<0.001],knee discomfort score [2(0,5) vs. 1(0,3),P<0.05], back pain visual analogue score (VAS) [5(4,5) vs. 2(1,3), P<0.001], and the volume of knee joint effusion by ultrasound (P<0.001) in 58 SpA patients were significantly lower than those before the operation.The rate [16.84%(16/95) vs. 6.32%(6/95),P=0.023] and grading (P=0.007) of popliteal cyst in RA were decreased after the operation. No statistically difference was observed in the rate [6.90% (4/58) vs. 5.17%(3/58), P=0.697] of popliteal cyst in patients with SpA, yet with a trend of decrease in 4 patients. Conclusion: This study provide evidence that knee arthroscopic synovectomy has a good effect for refractory knee arthritis, which can reduce disease activity, improve joint symptoms and decrease the grading of popliteal cyst.

[Therapeutic effect of combined use of interferon alpha-1b, interleukin-2 and thalidomide on reversing minimal residual disease in acute myeloid leukemia]

目的

探讨干扰素α-1b、白细胞介素2联合沙利度胺（“干白沙”方案）对急性髓系白血病（AML）患者微小残留病（MRD）的影响。

方法

对2016年7月至2018年6月收治的18例（17例来自郑州大学附属肿瘤医院，1例来自平顶山市第一人民医院）处于血液学完全缓解但MRD阳性的AML患者应用不同剂量的“干白沙”方案，监测其MRD水平变化。

结果

18例患者接受常规剂量“干白沙”方案1~2个月，7例患者MRD转阴，3例患者MRD水平明显下降，3例MRD水平升高，5例复发。MRD水平升高的3例患者接受加量的“干白沙”方案，2例MRD转阴，1例MRD水平下降。“干白沙”方案干预治疗MRD阳性AML总有效率为72.2%。根据治疗前MRD水平分组，MRD≥1.0%的患者有效率为57.1%（4/7），MRD<1.0%的患者有效率为81.8%（9/11）。

结论

“干白沙”方案可使血液学完全缓解但MRD阳性的AML患者MRD转阴或下降，增加方案药物剂量后疗效增加，疗效与治疗前MRD水平可能呈负相关。

[Risk factors associated with delirium for patients with hip fracture under the orthogeriatric unit mode]

Objective: To explore postoperative delirium (POD)risk factors for geriatric patients who suffered hip fracture under the care of orthogeriatric unit mode. Methods: Patients aged 65 years or older, who were admitted to the orthogeriatric unit in Beijing Jishuitan Hospital from April to October 2017 for hip fracture surgery, were eligible for this prospective cohort study. After univariable analysis, significant risk factors associated with POD were further evaluated with multivariable analysis, to establish independent risk factors associated with POD. Results: A total of 203 patients with an average age of 80(65-96)years were enrolled in the study. The overall incidence of POD was 9.4%(19/203)in which hyperactive and hypoactive type accounting for 84.2%(16/19)and 15.8%(3/19), respectively. Significant difference was found between POD and non-POD groups in patients' age (P=0.003), albumin(P=0.006), TSH(P=0.018), PaCO(2) level(P=0.003), visual analogue scale (VAS )both at rest (P=0.013)and movement(P=0.010) on post-operative day 1.The further Logistic stepwise regression analysis showed that significant differences existed between groups in age(P=0.027), albumin(P=0.003), PaCO(2)(P=0.014)and VAS at rest(P=0.002). Conclusion: The independent risk factors of POD in geriatric patients undergoing hip fracture under the orthogeriatric unit mode include patients' age, pre-operative albumin as well as PaCO(2) level and post-operative VAS at rest.

[Comparison of clinical manifestations according to HLA-B(27) genotype in ankylosing spondylitis patients: real-world evidence from smart management system for spondyloarthritis]

Objective: The aim of this study was to set up a large, longitudinal and prospective database to compare the clinical manifestations in human leucocyte antigen (HLA)-B(27) positive and negative patients with ankylosing spondylitis(AS) based on real-world evidence in Chinese population. Methods: A total of 897 outpatients with confirmed AS were recruited consecutively by smart management system for spondyloarthritis (SMSP) from April 13, 2016 to June 6, 2017 in Chinese PLA General Hospital from 30 provinces and autonomous regions. 801 patients with HLA-B(27) data were included in the analysis. Demographic and clinical parameters including Bath ankylosing spondylitis disease activity index (BASDAI), Bath ankylosing spondylitis functional index (BASFI), ankylosing spondylitis disease activity score (ASDAS), arthritis, enthesitis, Bath ankylosing spondylitis metrology index (BASMI), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were compared between HLA-B(27) positive and negative groups. Results: A total of 801 patients were included in the analysis with an average age of (30.7±8.8) years. There were 659 males and 142 females and HLA-B(27) was present in 88.0%(705/801). Males were significantly more in HLA-B(27) positive patients [83.3%(587/705) vs. 75.0%(72/96); P=0.047].The average age at disease onset was (22.3±7.6)years in HLA-B(27) positive patients and (24.4±8.7) years in HLA-B(2)7 negative ones (P=0.028).There was significant difference in diagnose delay between two groups [14.3(2.5,43.6)months in HLA-B(27) positive patients vs. 20.3(5.0,67.4) months in HLA-B(27) negative ones, P=0.041]. Anterior uveitis was found to be significantly more common in HLA-B(27) positive patients [18.9% (133/705)vs.7.3%(7/96),P=0.005], and knee involvement less common in HLA-B(27) positive patients [4.0%(27/682) vs.10.0%(9/90), P=0.010], conversely. CRP[6.5(3.0, 16.4)mg/L vs. 3.5(1.6, 12.3)mg/L] and ESR[11.0(4.0, 24.0)mm/1h vs. 7.0(3.0, 16.0)mm/1h] were significantly higher in HLA-B(27) positive patients(P=0.005,0.013, respectively).But no differences in BASDAI,ASDAS,BASFI and BASMI were obtained between two groups. Conclusions: HLA-B(27) positive patients had a higher proportion of males, a younger age of onset and a greater risk for occurrence of anterior uveitis, suggesting a poorer prognosis.

[Screening and follow-up for congenital heart disease in children aged 0-3 years in rural areas of Chongqing, China]

OBJECTIVE

To examine the incidence of congenital heart disease (CHD) in children aged 0-3 years in the rural areas of Chongqing, and to determine the suitable "screening-diagnosis-follow-up" system and screening indicators for CHD in these areas.

METHODS

Children aged 0-3 years from rural areas of the Fuling Disctrict of Chongqing were selected by cluster sampling. Using the "screening-diagnosis-evaluation system" employed at the levels of village/town, district/county, and province/city, the children were screened for seven indicators, i.e., family history of CHD, dyspnea, cyanosis, unique facial features, other congenital malformations, heart murmurs, and blood oxygen saturation (SpO₂<95%). Children who were positive for one or more indicators accepted echocardiography (ECG) for the diagnosis of CHD. CHD patients were evaluated for disease progression, given guided treatments, and followed-up by pediatric cardiologists.

RESULTS

Screening was performed for 10 005 out of the 10 281 children enrolled in the study (97.32% response rate). Among the 175 children who were positive for the indicators, 166 underwent ECG and 60 (0.6‰) were diagnosed with CHD, including 46 cases of simple CHD (76.65%), 11 cases of combined CHD (18.33%), and 3 cases of complex CHD (5.00%). Of the 7 screening indicators, heart murmur had the largest area under the ROC curve for the diagnosis of CHD. In addition, a combination of screening indicators (heart murmur, unique facial features, and other congenital malformations) was most effective for screening out CHD. The CHD patients were given surgical or intervention treatments, and followed up for 6 to 18 months. Ten patients improved without treatment, 13 patients received interventional or surgical treatment, 1 patient died of non-cardiac reasons. The remaining 36 patients were subjected to further follow-up.

CONCLUSIONS

Heart murmur alone and in combination with unique facial features and other congenital malformations are valuable tools for CHD screening in children aged 0-3 years. The "village/town-district/county-province/city" screening-diagnosis-evaluation systems are useful for the early detection, diagnosis, and treatment of CHD in infants and young children from the rural areas of Chongqing.

[Clinical value of Short Form-36 and clinical measures in a prospective cohort study of ankylosing spondylitis patients]

OBJECTIVE

To evaluate the clinical value of Short Form-36 (SF-36) questionnaire and the most commonly used clinical measures in a prospective cohort study of ankylosing spondylitis (AS) patients.

METHODS

A total of 517 AS patients were collected from the Department of Rheumatology, Chinese PLA General Hospital from August 2013 to September 2015. The Quality of Life (QoL) was assessed by SF-36 questionnaire and compared with the general population. The correlations between QoL and clinical measures of AS, including the Bath AS disease activity index (BASDAI), Bath AS functional index (BASFI), Bath AS metrology index (BASMI) et al, were analyzed.

RESULTS

BASDAI and BASFI were significantly correlated with SF-36 scores (r>0.3, P<0.01). Logistic multiple regression analysis showed that BASDAI, BASFI, BASMI and education had close correlation with the baseline global QoL, physical and mental health. Among these clinical measures, BASDAI variation showed the most important influence on the change of global QoL, physical health and mental health (OR=0.235, 0.209, 0.125; P<0.01).

CONCLUSIONS

SF-36 can objectively reflect the QoL of patients with AS. Clinical measures such as BASDAI and BASFI show great application value in this prospective cohort study of AS patients.

Increased efficiency of testicular tumor chemotherapy by ultrasound microbubble-mediated targeted transfection of siMDR1

The MDR1 gene encoding P-glycoprotein (P-gp) is an ATP-dependent drug efflux transporter and is related to drug resistance of yolk sac tumors. Drug resistence may be an important factor for the low efficiency of chemotherapy in the treatment of testicular tumors. P-gp, encoded by the MDR1 gene, is an ATP-binding cassette transporter. P-gp exhibits high expression in capillary endothelial cells of the testis and prevents the intracellular accumulation of chemotherapy agents in testicular tumor cells, resulting in drug resistance. In the present study, we aimed to use specific siRNA to silence the expression of the MDR1 gene and P-gp, leading to the reversal of multidrug resistance of testicular tumors and contributing a suitable condition for chemotherapy. Ultrasound microbubble-mediated delivery is a safe and effective tool for gene delivery. In the present study, we demonstrated that ultrasound microbubble-mediated delivery effectively improved the siMDR1 gene transfection in interstitial capillary endothelial cells of the testis, inhibited the expression of P-gp and increased daunorubicin accumulation. The testis tumor model was successfully constructed by injecting 1x10(7) yolk sac tumor cells in 3-week-old Sprague-Dawley rats. Ultrasound microbubble-mediated siMDR1 gene therapy improved the effect of chemotherapy on the testicular tumors. The testicular volume was reduced, the number of tumor cells within the testicular tissues decreased, and pathological changes were mostly recovered. Therefore, the present study indicated that ultrasound microbubble-mediated siMDR1 gene therapy in vivo reversed drug resistance by regulating P-gp expression, providing a promising method for the treatment of testicular tumors.

In vivo DNA-protein interactions at hypersensitive site 3.5 of the human beta-globin locus control region

Using ligation-mediated polymerase chain reaction and in vivo footprinting methods to study the status of DNA-protein interactions at hypersensitive site 3.5 (HS3.5) of the locus control region in K562 and HEL cells, we found that there was protein occupancy in vivo at HS3.5 in both cell lines and the status of DNA-protein interaction was different between K562 and HEL. These data provide direct evidence that specific nuclear factor-DNA complexes form in vivo at functionally important sequence motifs of the HS3.5 in erythroid cells. This indicates that HS3.5 may play an important role in the regulation of the beta-globin gene cluster. K562 is a human erythroleukemia cell line in which the embryonic epsilon-globin gene is predominantly expressed, while the HEL cell line expresses predominantly the fetal beta-globin genes. Thus, HS3.5 might also be involved in the regulation of developmental stage-specific expression of beta-globin genes. Our results are also consistent with the model that each hypersensitive site acts as a functional unit and HS3.5 may facilitate the formation of the HS3 functional unit.

Induction of differentiation and down-regulation of c-myb gene expression in ML-1 human myeloblastic leukemia cells by the clinically effective anti-leukemia agent meisoindigo

Meisoindigo, a second generation derivative of indirubin, is an effective chemotherapeutic agent with very low toxicity used in the treatment of chronic myeloid leukemia. To determine the nature of this activity, the effect of a nontoxic concentration (0.72 micrograms/mL) of this compound on ML-1 human myeloblastic leukemic cells was examined. At such a concentration, differentiation induction was found to be the most pronounced drug effect. During the 3-day drug incubation period, the viable cell number remained essentially constant, with approximately 48% of the cells demonstrating a mature phenotype with increased acid phosphatase activity and nitroblue tetrazolium dye reduction. As observed with other DNA-specific agents, induction of ML-1 differentiation by meisoindigo was accompanied by the down-regulation of c-myb gene expression. These data suggest that induction of leukemic cell differentiation associated with decreased c-myb expression may be one of the mechanisms of the antitumor action of meisoindigo.

[Pharmacokinetics of zinc acexamate (ZAC) in rats]

Zinc acexamate (ZAC) is a new antiulcer drug. This paper reports the pharmacokinetics of ZAC in rats after single oral administration. The concentrations in biological samples were detected by spectrophotometry. This study shows that the concentration-time curve of ZAC in blood conformed to a single-compartment open model after 250, 500 and 750 ng.kg-1 ig. ZAC absorption was fast and the peak plasma level appeared in 1.5 h. The Cmax, AUC and CL/F were shown to be dose dependent. Two hours after oral administration of ZAC to normal rats, the highest level of ZAC was present in the gastrointestinal tract, while appreciable ZAC was present in the kidney, liver, plasma and lung. The level of ZAC in heart, spleen and brain was lower, no drug was detected in muscles and uterus. Six hours after oral administration, the drug concentration in various tissues decreased rapidly, but that of the gastrointestinal decreased very slowly. Feces excretion was an important route of excretion. ZAC excretion was about 11.7% of the administered dosage in feces within 48 h period, and the excreted amount from urine and bile was very small.

Determination of DNA topoisomerase II activity from L1210 cells--a target for screening antitumor agents

DNA topoisomerase II was isolated from mouse leukemia L1210 cells and the activity was determined by using P4 phage knotted DNA and pBR 322 DNA as the substrates. Based on these results, a method for screening antitumor agents by using DNA topoisomerase II as a target was established. The experiments showed that DNA topoisomerase II catalyzed pBR 322 DNA breaking and relaxing which were reversible and dependent on ATP. The activity was increased 2-4 times in the presence of ATP 1 mmol.L-1. In contrast with type II enzyme, the activity of DNA topoisomerase I was completely inhibited in the presence of ATP 1 mmol.L-1 and had full activity in the absence of ATP. Type II enzyme also showed the unknotting activity by using p4 phage knotted DNA as a substrate. DNA cleavage and relaxing reaction induced by type II enzyme increased 5-fold in the presence of Doxorubicin (Dox) 1 microgram.ml-1 or daunorubicin (Dau). Etoposide (Eto) and aclarubicin B (Acl B) also stimulated the reaction at 100 micrograms.ml-1. The cleavage reaction resulted from topoisomerase II was inhibited by other agents, such as frankincense extracts, terpenic compounds (BC series).

Establishment and biological properties of mouse granulocytic leukemic cell line-L833

A granulocytic leukemic cell line, called L833 has been established through culturing in vitro from mouse bone marrow of transplantable granulocytic leukemia. More than 280 passages have been performed in 3 years. Cell growth has been rapid and stable. Incidence of tumour formation was 100% with various routes of inoculation. The nature of granulocytic leukemia was confirmed by examination of cytology, cytochemistry, pathology and ultrastructural changes. Analysis proved chromosomes to be hypodiploid with model number of 39, loss of chromosomes, and presence of a marker. Besides the chromosomal change as mentioned above, both L883-A and L833-B derived from colonies formed from the L833 cells cultured in semi-solid agar medium, have their own marker. The cell line was sensitive to various types of antitumour agents in varying degrees. It was also sensitive to ionizing radiation. D0 values of L833 and L883-A cells were 98.8 and 104.9 rad, respectively. The results were similar to that of L801. Establishment of this cell line is of important significance for studying leukemia and screening anti-tumour agents, as well as provides a useful direct, economic and precisely quantitative tool for other relative studies.

Establishment of a model of transplantable myelocytic leukemia (L801) in LACA mice

A transplantable myelocytic leukemia model of LACA mice, designated by the name of L801, was established by intravenous injection of spleen cell suspension from mice with radiation-induced myelocytic leukemia into mice of the same strain. Until now, for more than three years, the L801 has maintained stable and rapid growth and has been reproduced for over 130 serial passages. The incidence of leukemia in inoculated animals was approximately 100% and mean survival time was 10.9 +/- 2.1 days. The L801 is of myelocytic type which has been determined by cytological, cytochemical, pathological and ultrastructural observations. Its karyotype was hypodiploid, characterized by modal number of 39, loss of Y chromosome and an abnormal huge marker chromosome. The cell cycle duration of the L801 was 16 h. C-type viral particles were observed under the electron-microscope. The L801 was sensitive, to varying extents, to various anti-tumor agents. We presume that the L801 is a useful tool in studies on mechanism of leukemogenesis, anti-tumor agent screening and treatment of experimental tumors.