WGX50 mitigates doxorubicin-induced cardiotoxicity through inhibition of mitochondrial ROS and ferroptosis

BACKGROUND

Doxorubicin (DOX)-induced cardiotoxicity (DIC) is a major impediment to its clinical application. It is indispensable to explore alternative treatment molecules or drugs for mitigating DIC. WGX50, an organic extract derived from Zanthoxylum bungeanum Maxim, has anti-inflammatory and antioxidant biological activity, however, its function and mechanism in DIC remain unclear.

METHODS

We established DOX-induced cardiotoxicity models both in vitro and in vivo. Echocardiography and histological analyses were used to determine the severity of cardiac injury in mice. The myocardial damage markers cTnT, CK-MB, ANP, BNP, and ferroptosis associated indicators Fe2+, MDA, and GPX4 were measured using ELISA, RT-qPCR, and western blot assays. The morphology of mitochondria was investigated with a transmission electron microscope. The levels of mitochondrial membrane potential, mitochondrial ROS, and lipid ROS were detected using JC-1, MitoSOX™, and C11-BODIPY 581/591 probes.

RESULTS

Our findings demonstrate that WGX50 protects DOX-induced cardiotoxicity via restraining mitochondrial ROS and ferroptosis. In vivo, WGX50 effectively relieves doxorubicin-induced cardiac dysfunction, cardiac injury, fibrosis, mitochondrial damage, and redox imbalance. In vitro, WGX50 preserves mitochondrial function by reducing the level of mitochondrial membrane potential and increasing mitochondrial ATP production. Furthermore, WGX50 reduces iron accumulation and mitochondrial ROS, increases GPX4 expression, and regulates lipid metabolism to inhibit DOX-induced ferroptosis.

CONCLUSION

Taken together, WGX50 protects DOX-induced cardiotoxicity via mitochondrial ROS and the ferroptosis pathway, which provides novel insights for WGX50 as a promising drug candidate for cardioprotection.

Selective Clearance of Senescent Chondrocytes in Osteoarthritis by Targeting Excitatory Amino Acid Transporter Protein 1 to Induce Ferroptosis

Aims: This study aimed at exploring the mechanism of ferroptosis (an iron-dependent form of nonapoptotic cell death) resistance in senescent chondrocytes (SenChos). Results: In this study, by utilizing metabolomics and single-cell RNA sequencing, we found that hyperactivation of ferroptosis metabolism was one of the most prominent metabolic features in SenChos. Interestingly, however, SenChos were able to survive in this state and were resistant to ferroptosis-induced cell death. Next, we elucidated that this survival mechanism of SenChos could be primarily attributed to overexpression of the membrane protein excitatory amino acid transporter protein 1 (EAAT1), which can increase intracellular glutamate (Glu) levels and activate the glutathione system to counteract ferroptosis. In addition, 2-amino-5,6,7,8-tetrahydro-4-(4-methoxyphenyl)-7-(naphthalen-1-yl)-5-oxo-4H-chromene-3-carbonitrile (UCPH-101) (a specific inhibitor of EAAT1) and siRNA-EAAT1 were able to substantially increase the sensitivity of SenChos to ferroptosis and to induce cell death, with no apparent effects on the normal cells. Administration of an intraarticular injection of UCPH-101 caused inhibition of EAAT1 selectively, cleared SenChos from cartilage, improved the cartilage homeostasis, and significantly delayed the progression of osteoarthritis (OA). Innovation: This work supports a relevant role for EAAT1 in ferroptosis resistance mechanism for SenChos, revealing a potential therapeutic target of OA. Conclusions: EAAT1-Glu-glutathione peroxidase 4 anti-ferroptosis axis is a key survival mechanism for SenChos, and EAAT1 is an effective and specific target for anti-senescence therapy in OA. Antioxid. Redox Signal. 39, 262-277.

Serum levels of tumor markers and their clinical significance in epithelial ovarian cancer

OBJECTIVES

Tumor markers have been widely used clinically. Detection of serum CA125 is one of the commonly used clinical methods for early screening and early diagnosis of epithelial ovarian cancer, but it is difficult to diagnose epithelial ovarian cancer with a single specific tumor marker. In this study, the combinatorial tumor marker detection method was used to compare the value of each tumor marker alone and different combinations in the diagnosis of epithelial ovarian cancer.

METHODS

The clinical data of patients with epithelial ovarian cancer (n=65) and ovarian benign disease (n=29) were collected. Multiple tumor marker protein chip was used to detect cancer antigen 125 (CA125), carbohydrate antigen 242 (CA242), alpha-fetoprotein (AFP), beta-human chorionic gonadotropin (β-HCG), carcinoembryonic antigen (CEA), cancer antigen 199 (CA199), neuron-specific enolase (NSE), Ferritin, cancer antigen 153 (CA153), and human growth hormone (HGH) serum levels, and to compare the differences between the benign and malignant ovarian tumors. The correlation between tumor markers and clinicopathologic features for ovarian epithelial carcinoma was analyzed by χ2 test. Spearman rank analysis showed the correlation between CA125 expression level and other tumor markers in epithelial ovarian cancer and the correlation between age and the above 10 tumor markers. Sensitivity, specificity, positive predictive value, negative predictive value, Youden index, and diagnostic efficiency were used to evaluate the diagnostic value of single tumor marker and the combination of tumor markers.

RESULTS

The levels of β-HCG, NSE, CA153, and CA125 in the epithelial ovarian cancer group were higher than those in the ovarian benign disease group. The level of NSE in the serum of patients with epithelial ovarian cancer was related to the clinical stage of patients. In addition, the levels of CA242, β-HCG, CEA, NSE, Ferritin, CA153 in the serum of patients with epithelial ovarian cancer were positively correlated with CA125 (rs=0.497, P<0.001; rs=0.612, P<0.001; rs=0.358, P=0.003; rs=0.680, P<0.001; rs=0.322, P=0.009; rs=0.609, P<0.001, respectively), and the levels of β-HCG, Ferritin, CA153 were positively correlated with the patient's age (rs=0.256, P=0.040; rs=0.325, P=0.008; rs=0.249, P=0.046, respectively). In the diagnosis of epithelial ovarian cancer, the sensitivity, Youden index, and diagnostic efficiency of CA125 detection alone were higher than the results of the other 9 separate detections. When CA153, CA199, CA242, Ferritin, and CEA were combined with CA125, the sensitivity of the combined detection of different combinations was higher than that of CA125 alone. The combined detection sensitivities of CA125+CEA and CA125+Ferritin+CEA were 89.2% and 90.8%, respectively, and the diagnostic efficiencies were both 84.1%, which were higher than those of other combinations. The Youden index of CA125+CEA joint detection was 0.616, which was higher than those of other combinations.

CONCLUSIONS

CA125 has a high diagnostic value in the diagnosis of epithelial ovarian cancer. The detection of combined tumor markers in serum has higher sensitivity and specificity in epithelial ovarian cancer.

[Status and associated factors of pre-exposure prophylaxis use among men who have sex with men in 24 cities in China]

Objective: To understand the cognition and medication use of pre-exposure prophylaxis (PrEP) among men who have sex with men (MSM) in China and its associated factors. Method: From August 25 to September 5, 2021, 2 447 MSM were recruited in 24 cities to complete the online questionnaire through a male social interaction platform, Blued 7.5 software. The survey contents included demographic information of the respondents, PrEP awareness and usage, and risk behaviors. Descriptive analysis and multi-level logistic regression were performed for data analysis. SPSS 24.0 and SAS 9.4 software were used for statistical analysis. Results: Among the 2 447 respondents of MSM, 1 712 (69.96%) had heard of PrEP, 437 (17.86%) ever used PrEP, 274 (11.20%) were on PrEP, and 163 (6.66%) had discontinued PrEP; among the 437 cases (whoever used PrEP), more than 61.88% (388/627) adopted emtricitabine/tenofovir disoproxil fumarate regimen, and most of them adopted on-demand regimen. The average PrEP dosage reported in the past year is 1.12 tabletsper person per week. PrEP purchase was primarily via an online channel, and the most concerned factor was the PrEP effectiveness on HIV prevention. The most common reasons for discontinuing PrEP, reported by 163 cases, were the lack of HIV risk perception, the use of a condom to prevent HIV, and the economic burden of PrEP use. The logistic regression analysis showed that PrEP use among MSM in 24 cities was statistically associated with age, monthly income, ever having unprotected anal sex in the past year, used sexual drugs and sexually transmitted disease (STD) diagnosis in the past year. Compared with MSM aged 18-24, the proportion of MSM was relatively lower among those aged 25-44, who discontinued the PrEP (aOR=0.54,95%CI:0.34-0.87) or never used PrEP (aOR=0.62,95%CI:0.44-0.87). The proportion of unprotected anal sex among MSM currently on PrEP use was higher than those who have stopped PrEP and never used PrEP (all P<0.05). Those MSM group, with monthly income higher than 5 000 Yuan, used sexual drugs and STD diagnosis in the past year were more likely to have a higher rate for PrEP usage (all P<0.05). Conclusions: Currently, pre-exposure prophylaxis in the MSM group is primarily obtained via the online channel and adopted in an on-demand mode. Although the PrEP users have reached a certain proportion, it is still necessary to strengthen health education on the PrEP effects and side effects of MSM and to improve the awareness and use rate, especially for young MSM group, which can be combined with the advantages of the internet targeting its needs and use barriers.

[The prevalence of HIV, hepatitis C virus and syphilis and related factors among cross-border couples in Mangshi county, Dehong Dai and Jingpo Autonomous Prefecture of Yunnan province from 2017 to 2019]

Objective: To understand the prevalence of HIV, hepatitis C virus (HCV) and syphilis and related factors among cross-border couples in Mangshi county, Dehong autonomous prefecture, Yunnan province. Methods: From May, 2017 to April, 2019, 2 500 couples with 5 000 cross-border marriages were selected by using cluster sampling method. The demographic characteristics, AIDS-related health services, HIV, HCV, syphilis infection and other information were collected through questionnaires and laboratory tests. The influencing factors of HIV, HCV and syphilis infection were analyzed by multivariate logistic regression model. Results: A total of 2 500 couples with cross-border marriage were investigated, among which 2 438 (97.5%) couples were Chinese men with Myanmar women. The average age of 5 000 participants was (34.16±9.00) years. Most of them were minority groups (59.9%), farmers (98.5%), education years ≤6 years (81.4%), marriage years>3 years (80.0%), and from mountainous areas (61.7%). The HIV prevalence of Chinese and Myanmar populations was 1.7% (43/2 500) and 2.0% (49/2 500), respectively. The HCV infection rates were 2.0% (49/2 500) and 1.3% (32/2 500), respectively and the infection rates of syphilis were 0.4% (10/2 500) and 0.2% (4/2 500), respectively. There were no statistically significant differences in the prevalence of three diseases among Chinese and Myanmar populations (P>0.05). The multivariate analysis showed that compared with those aged ≤ 30 years, having lower AIDS awareness, never receiving HIV testing, without HCV and syphilis infection, HIV prevalence was higher among those aged>30 years (OR=3.21, 95%CI: 1.80-5.73), having higher AIDS awareness (OR=17.41, 95%CI: 4.27-70.91), receiving HIV testing (OR=4.93, 95%CI: 2.72-8.92), with HCV infection (OR=5.64, 95%CI: 2.72-11.70) and syphilis infection (OR=8.37, 95%CI: 1.63-43.08). Compared with those aged ≤ 30 years, having marriage years ≤ 3 years, and with HIV negatives, HCV infection rate was higher among those age>30 years (OR=3.02, 95%CI: 1.69-5.38), having marriage years>3 years (OR=2.24, 95%CI: 1.34-3.74), and with HIV positives (OR=6.69, 95%CI: 3.29-13.59). Compared with those having HIV negatives, the syphilis infection rate was relatively higher among participants with HIV positives (OR=9.07, 95%CI: 2.00-41.10). Conclusion: The prevalence of HIV, HCV, and syphilis among cross-border couples in Mangshi county, Dehong autonomous prefecture of Yunnan province is relatively high. Age, AIDS awareness, HIV testing history, and the length of marriage are associated with the HIV, HCV, and syphilis infection.

[Evaluation of China Comprehensive AIDS Response Program in 2020]

Objective: To analyze the work indicators of China Comprehensive AIDS Response Program (China CARES) and provide reference for future work of the program. Methods: The scores of each indicator were calculated, and different scores among different types of program areas were compared. The M(Q₁,Q₃) was used to describe the score of each indicator. The entropy weight method was used to calculate the composite score of each indicator and the composite score was translated into a 100-point system and compared among indicators. Results: In terms of the first-level indicators, organizational leadership and management (96.0 points), publicity and education (94.0 points), and innovative strategies and measures (98.0 points) got relatively high scores; while comprehensive social governance of AIDS prevention (72.0 points) was with the lowest score. The scores of publicity and education and comprehensive intervention in county-level program areas were significantly lower than those in urban areas. For secondary indicators, the indicator with relatively lower scores included "condom use among female sex workers last time" (70.0 points)", "at least one local key population has an increase in the number of people receiving HIV testing compared with the previous year" (70.0 points)", "colleges and occupational schools set up AIDS-related self-service facilities" (65.0 points), "HIV testing among the arrested people suspected of prostitution, adultery, drug users and traffickers" (55.0 points) and "condom use among men who have sex with men during last episode" (50.0 points). The "indicator 3 comprehensive intervention" contributed most to the evaluation, while "indicator 7 innovation strategies and measures" played a minor role in the evaluation results. Conclusions: The overall situation of AIDS Response Program in 2020 was good, but the progress in different word areas was not yet balanced. The two areas of comprehensive intervention and comprehensive social governance of AIDS prevention should be strengthened. It is also suggested that relevant indicators be adjusted appropriately to improve evaluation indicators system and comprehensively promote the program.

Identification and Validation of N6-Methyladenosine-Related Biomarkers for Bladder Cancer: Implications for Immunotherapy

N6-methyladenosine (m⁶A) has emerged as one of the most important modifications of RNA. Based on the expression of 23 different modes of m⁶A regulatory factors, we identified three different m⁶A modification patterns in bladder cancer. The effects of the three different modes of m⁶A modification on clinicopathological characteristics, immune cell infiltration levels and expression levels of immune checkpoint genes were comprehensively analyzed. In addition, the effects of different modes of m⁶A modification on the therapeutic efficacy of anti-PD-L1 immunotherapy (atezolizumab) are also discussed. Our results confirm that m⁶A methylation plays an important role in immune cell recruitment in the tumor microenvironment of bladder cancer, which influences the efficacy of anti-PD-L1 therapy for bladder cancer. We further confirmed the important role of FTO protein in the biological function of bladder cancer cells by performing in vitro experiments. FTO functions as an oncogene in bladder cancer cells, and upon FTO knockdown, the level of m⁶A enzyme activity in bladder cancer cells was significantly increased, apoptosis was increased, and cell proliferation and cell invasion were reduced. In addition, our study also confirmed that K216H and K216E are probably important targets for regulating FTO. We provide new insights into the regulatory pathways of the immune microenvironment and the methylation function of m⁶A in bladder cancer, which will help in designing novel diagnostic methods, prognostic tools, and therapeutic targets.

Wireless power transfer system with enhanced efficiency by using frequency reconfigurable metamaterial

The wireless power transfer (WPT) system has been widely used in various fields such as household appliances, electric vehicle charging and sensor applications. A frequency reconfigurable magnetic resonant coupling wireless power transfer (MRCWPT) system with dynamically enhanced efficiency by using the frequency reconfigurable metamaterial is proposed in this paper. The reconfigurability is achieved by adjusting the capacitance value of the adjustable capacitor connected in the coil of the system. Finite element simulation results have shown that the frequency reconfigurable electromagnetic metamaterial can manipulate the direction of the electromagnetic field of the system due to its abnormal effective permeability. The ultra-thin frequency reconfigurable metamaterial is designed at different working frequencies of 14.1 MHz, 15 MHz, 16.2 MHz, 17.5 MHz, 19.3 MHz, 21.7 MHz and 25 MHz to enhance the magnetic field and power transfer efficiency (PTE) of the system. Frequency reconfigurable mechanism of the system with the frequency reconfigurable metamaterial is derived by the equivalent circuit theory. Finally, further measurement which verifies the simulation by reasonable agreement is carried out. PTE of the system by adding the metamaterial are 59%, 73%, 67%, 66%, 65%, 60% and 58% at different working frequencies. PTE of the system with and without the metamaterial is 72% and 49% at the distance of 120 mm and the frequency of 15 MHz, respectively.

CircRNA-011235 Counteracts The Deleterious Effect of Irradiation Treatment on Bone Mesenchymal Stem Cells by Regulating The miR-741-3p/CDK6 Pathway

OBJECTIVE

The present work was aimed at uncovering the effect of circRNA-011235 (circ-011235) on irradiation-induced bone mesenchymal stem cells (BMSCs) injury and its regulatory mechanism, with a view to establish a scientific basis for its possible medical applications.

MATERIALS AND METHODS

In this experimental study, after irradiation with different doses (0, 2, 4, 6 GY), the relative expression levels of circ-011235, miR-741-3p, and cyclin-dependent kinases 6 (CDK6) were detected in the BMSCs, using the real time-quantitative polymerase chain reaction (RT-qPCR). The overexpression effects of circ-011235 and CDK6 on the cell proliferation in irradiation-treated BMSCs were measured by the Cell Counting Kit-8 (CCK8) assay. And also, their effects on the cell cycle were evaluated by flow cytometry. RT-qPCR and immunoblotting were performed to detect the effects of pcDNA-circ-011235 and pcDNA-CDK6 on the expression of cyclin D1 and cyclindependent kinases 4 (CDK6) at the gene and protein levels, respectively.

RESULTS

Irradiation treatment elevated the expression of circ-011235 and CDK6, but reduced miR-741-3p expression in the BMSCs with a dose-dependent effect. The proliferation of BMSCs was significantly inhibited in the irradiation treatment group, while the overexpression of circ-011235 and CDK6 effectively attenuated this inhibition. Also, overexpression of circ-011235 and CDK6 elevated the expression of cyclin D1 in irradiation-treated BMSCs, but had no significant effect on the CDK4 expression.

CONCLUSION

Our results demonstrated that circ-011235 up-regulated the expression of cyclin D1 via miR-741-3p/ CDK6 signal pathway, thereby promoting cell cycle progression and proliferation of irradiation-treated BMSCs. This finding suggested circ-011235/ miR-741-3p/CDK6 pathway exerted a protective role in the response to irradiation and will be a potential new target for future research on the mechanism involved in the resistance of BMSCs to radiation.

[A cohort study on the incidence of HIV infection in drug abusers among men who have sex with men in Shanghai and Tianjin]

Objective: To analyze the incidence of HIV infection and identify associated risk factors in drug abusers among men who have sex with men (MSM) in Tianjin and Shanghai through a cohort study and provide a basis for HIV prevention in this population. Methods: A prospective cohort study was conducted among MSM who had a history of drug abuse in the past six months from June 2016 to June 2018 in the two cities. MSM were investigated to obtain information on sociodemographic characteristics, HIV-related sexual behaviors, and drug abuse. Follow-up investigation and HIV testing were carried out based on the baseline survey and testing. Cox regression analysis was conducted to identify the risk factors for HIV infection. Results: There were 455 eligible subjects, and 16 new HIV infection cases were identified in the 2-year follow-up survey. The cumulative follow-up time was 586.08 person-years, and the incidence of HIV infection was 2.73/100 person-years. The multivariate Cox regression analysis results showed that compared with those aged ≥25 years, consistent condom use during anal sex with men in the past six months, without mixed-use of drugs, these aged <25 years (HR=5.01, 95%CI: 1.09-23.11), inconsistent condom use during anal sex with men in the past six months (HR=1.58, 95%CI: 1.04-2.41) and mixed-use of drugs (HR=1.92, 95%CI: 1.08-3.40) were significantly associated with HIV infection in this cohort. Conclusions: The younger age, inconsistent condom use during anal sex with men, and mixed drug use appeared as risk factors of new HIV infection in drug abusers among MSM. HIV prevention and intervention in this population should be further strengthened.

[Value of maximum area stenosis combined with perivascular fat attenuation index in predicting hemodynamically significant coronary artery disease]

OBJECTIVE

To investigate the combined value of coronary computed tomography angiography (CCTA) indicators and perivascular fat attenuation index (FAI) in predicting hemodynamically significant coronary artery disease.

METHODS

We retrospectively analyzed the data of patients undergoing CCTA in Chinese PLA General Hospital from 2017 to 2019, who were also examined for fractional flow reserve (FFR) with invasive coronary angiography within one month before inclusion. The CCTA indicators at the vascular level were measured, including plaque distribution, coronary artery calcification score, lesion length, maximum diameter stenosis, maximum area stenosis (MAS), total plaque burden (TPB), perivascular FAI, and CT-FFR based on machine learning. Lesion-specific hemodynamically significant coronary artery disease was diagnosed for an invasive FFR≤0.8.

RESULTS

A total of 99 patients with 124 involved coronary arteries were included in this analysis. At the vascular level, according to the results of invasive FFR, coronary artery calcification score, maximum diameter stenosis, MAS and the total plaque burden were significantly higher in patents with a FFR≤0.8 than in those with a FFR>0.8; the perivascular FAI (P < 0.01) and CT-FFR (P < 0.01) also differed significantly between the two groups. The AUC of MAS combined with perivascular FAI was 0.818, which was not significantly different from that of CT-FFR (P=0.076).

CONCLUSION

The combination of MAS and perivascular FAI has good diagnostic performance in predicting hemodynamically significant coronary stenosis, which is comparable with that of CT-FFR.

Dosimetric verification of stereotactic body radiotherapy treatment plan via ArcCHECK-3DVH system

OBJECTIVES

To study the feasibility of ArcCHECK-3DVH system in dosimetric verification for stereotactic body radiaotherapy (SBRT) with flattening filter free (FFF) model.

METHODS

SBRT treatment plans for 57 patients were introduced into ArcCHECK phantom and recalculated. The calculated dose distribution of treatment planning system and the measured dose distribution of ArcCHECK phantom were compared by γ analysis. Then the 3 dimensional dose distribution of target and organs at risk was reconstructed by 3DVH software. The reconstructed dose and calculated dose with treatment planning system (TPS) were compared, and the dose volume γ pass rate and deviation of dose volume parameters to the target and organs at risk were quantitatively valuated.

RESULTS

Based on the threshold criteria (3%, 3 mm, 10%), namely the deviation of measuring points between the planned value and the measured value was less than 3%, and the proportion of points with similar values in the plane or sphere with the center of the point and the radius of 3 mm was 10%, the relative and absolute dose pass rates of SBRT treatment plans in ArcCHECK system via γ analysis were greater than 95%. Based on the stricter threshold criteria (2%, 2 mm, 10%), the relative and absolute dose pass rates of SBRT treatment plan in ArcCHECK system via γ analysis were about 93%. In 3DVH dose verification, the γ pass rate of target and organs at risk was exceed 97%, and the deviations in 3DVH of the target and organs at risk were less than ±5%.

CONCLUSIONS

The ArcCHECK-3DVH system in dose verification can provide more comprehensive dose distribution information to reasonably evaluate the SBRT plan, with more significance for guiding clinical treatment.

CircRNA-016901 silencing attenuates irradiation-induced injury in bone mesenchymal stem cells via regulating the miR-1249-5p/HIPK2 axis

Currently, bone marrow transplantation remains the basic treatment for various hematological tumors and irradiation is one of the most important pretreatment methods. However, irradiation pretreatment may result in damage to bone mesenchymal stem cells (BMSCs). The present study aimed to investigate the effect of circular RNA-016901 (circ-016901) on the injury of irradiation-induced BMSCs and the underlying mechanism. The expression levels of circ-016901, microRNA-1249-5p (miR-1249-5p) and homeodomain interacting protein kinase 2 (HIPK2) in irradiation-induced mouse BMSCs at various irradiation doses were detected via reverse transcription-quantitative PCR (RT-qPCR). The effect of circ-016901 on cell proliferation was examined using Cell Counting Kit-8 assays following silencing or overexpression of circ-016901. Cell apoptosis was detected by flow cytometry and caspase-3/7 activity. The expression of autophagy-related markers, including Beclin-1 and LC3-II/I, was detected at the mRNA and protein levels by RT-qPCR and western blotting, respectively. Irradiation treatment upregulated the expression of circ-016901 and HIPK2 and downregulated miR-1249-5p expression. The expression levels of LC3-II/I and Beclin-1 in BMSCs were downregulated in a dose-dependent manner. Silencing of circ-016901 promoted proliferation of irradiation-induced BMSCs and attenuated irradiation-induced apoptosis. Moreover, silencing of circ-016901 elevated the expressions of LC3-II/I and Beclin-1 in irradiation-induced BMSCs. Similar results were obtained with miR-1249-5p overexpression and HIPK2 silencing. These results demonstrated that circ-016901 silencing attenuated injury in irradiation-induced mouse BMSCs by regulating the miR-1249-5p/HIPK2 axis, providing a novel target for future research on the mechanism of radiation resistance in BMSCs.

Volatile anaesthesia and peri-operative outcomes related to cancer: a feasibility and pilot study for a large randomised control trial

Published data suggest that the type of general anaesthesia used during surgical resection for cancer may impact on patient long-term outcome. However, robust prospective clinical evidence is essential to guide a change in clinical practice. We explored the feasibility of conducting a randomised controlled trial to investigate the impact of total intravenous anaesthesia with propofol vs. inhalational volatile anaesthesia on postoperative outcomes of patients undergoing major cancer surgery. We undertook a randomised, double-blind feasibility and pilot study of propofol total intravenous anaesthesia or volatile-based maintenance anaesthesia during cancer resection surgery at three tertiary hospitals in Australia and the USA. Patients were randomly allocated to receive propofol total intravenous anaesthesia or volatile-based maintenance anaesthesia. Primary outcomes for this study were successful recruitment to the study and successful delivery of the assigned anaesthetic treatment as per randomisation arm. Of the 217 eligible patients approached, 146 were recruited, a recruitment rate of 67.3% (95%CI 60.6-73.5%). One hundred and forty-five patients adhered to the randomised treatment arm, 99.3% (95%CI 96.2-100%). Intra-operative patient characteristics and postoperative complications were comparable between the two intervention groups. This feasibility and pilot study supports the viability of the protocol for a large, randomised controlled trial to investigate the effect of anaesthesia technique on postoperative cancer outcomes. The volatile anaesthesia and peri-operative outcomes related to cancer (VAPOR-C) study that is planned to follow this feasibility study is an international, multicentre trial with the aim of providing evidence-based guidelines for the anaesthetic management of patients undergoing major cancer surgery.

[A survey on sexual needs and factors of HIV risky sexual behaviors among elderly men at different ages in two communities of Qiandongnan Miao and Dong autonomous prefecture]

Objective: To understand sexual needs and factors of risky sexual behaviors among elderly men at different ages in two communities of Qiandongnan Miao and Dong autonomous prefecture and provide basis for targeted HIV prevention and intervention. Methods: Two communities in the prefecture were selected as study sites. Questionnaire surveys were carried out among elderly men aged 50 and over who visited or consulted in the communities from June to December 2018, and they were tested for HIV and syphilis antibodies. Results: Among 400 elderly men, 209 (52.2%) were 50-64 years old, and 191(47.8%) were above 65 years old. They were mainly Miao people, accounting for 66.3% (265/400), and 235 (58.8%) had an education no more than 6 years. HIV awareness of the two age groups were only 25.8% (54/199) and 26.2% (50/191), respectively. Among those aged 50-64, 142 (68.0%) felt normal sexual desire, and 153 (73.6%) reported penile erections or erections in most cases whenever sex, and 52.9% (110) ejaculated most of the time. HIV prevalence was 1.0% (4/400). Compared with the over 65-year-old group, the proportion of having sex with spouse/stable partners (89.5%, 179/200), proportion of no condom use with their spouse/stable sexual partners during the most recent sex (93.8%, 168/179), proportion of having casual sex (11.0%, 23/209) and commercial sex (3.8%, 8/209) were all higher among 50-64 age group. In comparison to those aged over 65 years old, average monthly income>3 000, and use of sex helper, aged 50-64 (OR=2.70, 95%CI: 1.22-5.95), average monthly income ≤1 000 yuan (OR=2.79, 95%CI: 1.25-6.21), and no use of sex helper (OR=3.78) (95%CI: 1.65-8.67) were related factors of HIV risky sexual behavior last time. Conclusion: Elderly men in the minority prefecture had low HIV awareness. Compared with those≥65 years old, the 50-64 age group had more active sexual behaviors and higher sexual needs. Those from 50-64 age group, with lower economic level and good sexual ability were more likely to have HIV risky sexual behaviors.

CGRP Modulates Orofacial Pain through Mediating Neuron-Glia Crosstalk

Calcitonin gene-related peptide (CGRP) plays a crucial role in the modulation of orofacial pain, and we hypothesized that CGRP mediated a neuron-glia crosstalk in orofacial pain. The objective of this study was to elucidate the mechanisms whereby CGRP mediated trigeminal neuron-glia crosstalk in modulating orofacial pain. Orofacial pain was elicited by ligating closed-coil springs between incisors and molars. Trigeminal neurons and satellite glial cells (SGCs) were cultured for mechanistic exploration. Gene and protein expression were determined through immunostaining, polymerase chain reaction, and Western blot. Orofacial pain was evaluated through the rat grimace scale. Our results revealed that the expressions of CGRP were elevated in both trigeminal neurons and SGCs following the induction of orofacial pain. Intraganglionic administration of CGRP and olcegepant exacerbated and alleviated orofacial pain, respectively. The knockdown of CGRP through viral vector-mediated RNA interference was able to downregulate CGRP expressions in both neurons and SGCs and to alleviate orofacial pain. CGRP upregulated the expression of inducible nitric oxide synthase through the p38 signaling pathway in cultured SGCs. In turn, L-arginine (nitric oxide donor) was able to enhance orofacial pain by upregulating CGRP expressions in vivo. In cultured trigeminal neurons, L-arginine upregulated the expression of CGRP, and this effect was diminished by cilnidipine (N-type calcium channel blocker) while not by mibefradil (L-type calcium channel blocker). In conclusion, CGRP modulated orofacial pain through upregulating the expression of nitric oxide through the p38 signaling pathway in SGCs, and the resulting nitric oxide in turn stimulated CGRP expression through N-type calcium channel in neurons, building a CGRP-mediated positive-feedback neuron-glia crosstalk.

Comprehensive analysis of serum tumor markers and BRCA1/2 germline mutations in Chinese ovarian cancer patients

Background

The serum tumor markers has been widely used in ovarian cancer diagnosis. BRCA1/2 germline mutations are the most common predisposing factors for ovarian cancer development. This study aimed to comprehensively investigate serum tumor markers and BRCA1/2 germline mutations and analyze their associations with ovarian cancer.

Methods

Levels of 11 serum tumor markers were examined in ovarian cancer patients and controls with benign gynecologic diseases. By integrating multiplex PCR and next‐generation sequencing technologies, BRCA1/2 germline mutations were analyzed and confirmed by Sanger sequencing. The discriminative models with serum tumor markers and BRCA1/2 mutation status were constructed for ovarian cancer detection and patient stratification.

Results

Among 11 markers, six of them were significantly elevated and only beta‐human chorionic gonadotropin (β‐HCG) was significantly reduced in ovarian cancer patients. A total of 54 (23.3%) ovarian cancer patients were found to harbor BRCA1/2 deleterious mutations, and BRCA1/2 mutations were significantly associated with Hereditary Breast and Ovarian Cancer‐related tumors and family history of cancer. Carbohydrate antigen 125 showed a good performance in ovarian cancer detection as a single marker (AUC = 0.799), while a panel of eight markers showed a good performance in BRCA1 mutation detection with an AUC value of 0.974. In addition, a panel of five serum tumor markers combined with BRCA1/2 mutation status showed a good performance in lymph node metastasis prediction (AUC = 0.843).

Conclusions

We found the association between BRCA1/2 germline mutation status and serum tumor marker levels, and identified discriminative models that combined serum tumor markers with BRCA1/2 mutation status for ovarian cancer detection and patient stratification.

Intraarticular senescent chondrocytes impair the cartilage regeneration capacity of mesenchymal stem cells

Background

Senescent cells exert a significant influence over their surrounding cellular environment. Senescent chondrocytes (SnChos) were found to be accumulated in degenerated cartilage present in joints affected by osteoarthritis. The influence of SnChos on exogenously transplanted stem cells has yet to be reported.

Methods

In this study, we evaluated the interactions between SnChos and bone marrow mesenchymal stem cells (BMSCs) when co-cultured as well as in the intra-articular senescent microenvironment (IASM). The effect of IASM on cartilage regeneration was also assessed.

Results

It was found that a small fraction of SnChos induced BMSC cellular senescence and apoptosis. SnChos also inhibited proliferation, facilitated stemness, and suppressed chondrogenic differentiation of BMSCs. BMSCs induced the apoptosis of SnChos, reduced the proportion of SnChos, stimulated SnChos proliferation, and revealed a bidirectional effect on SnChos inflammaging. IASM significantly suppressed the survival, proliferation, and appropriate differentiation of grafted BMSCs in vivo, all of which impaired cartilage regeneration. Anti-senescence agent ABT-263 was able to partly rescue the cells from the negative effects of SnChos.

Conclusions

The SnChos and BMSCs interacted with each other at cellular senescence, apoptosis, proliferation, differentiation, and cell functions. This interaction impaired the cartilage repair of MSCs. Anti-senescence agent provided a possible solution for this impairment.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1193-1) contains supplementary material, which is available to authorized users.

[Dosimetric verification of flattening filter free model based on TrueBeam accelerator using ArcCheck system]

OBJECTIVE

To study the feasibility of ArcCheck verification system in dosimetric verification for stereotactic radiotherapy (SRT) the stereotactic radiotherapy (SRT) with flattening filter free (FFF) model.
 Methods: A total of 76 cases under SRT treatment plans were introduced into ArcCheck phantom and recalculated. Threshold criteria was set as (3%, 3 mm, 10%) or (2%, 2 mm, 10%). The calculated dose distribution and the measured dose distribution of ArcCheck phantom were compared by means of distance to agree (DTA) and Gamma analysis method respectively.
 Results: Based on the threshold criteria (3%, 3 mm, 10%), the relative and absolute mean pass rates of SRT treatment plans by DTA and Gamma analysis were greater than 95%. Based on the threshold criteria (2%, 2 mm, 10%), the relative and absolute mean pass rates of SRT treatment plan by DTA and Gamma analysis were about 90%. The dose pass rate of Gamma analysis method was slightly higher than that of DTA analysis method (P<0.001).
 Conclusion: The ArcCheck verification system is a rapid and accurate method for SRT dose verification, and discrepancies are found in different analysis methods.

Purinergic signaling and energy homeostasis in psychiatric disorders

Purinergic signaling regulates numerous vital biological processes in the central nervous system (CNS). The two principle purines, ATP and adenosine act as excitatory and inhibitory neurotransmitters, respectively. Compared to other classical neurotransmitters, the role of purinergic signaling in psychiatric disorders is not well understood or appreciated. Because ATP exerts its main effect on energy homeostasis, neuronal function of ATP has been underestimated. Similarly, adenosine is primarily appreciated as a precursor of nucleotide synthesis during active cell growth and division. However, recent findings suggest that purinergic signaling may explain how neuronal activity is associated neuronal energy charge and energy homeostasis, especially in mental disorders. In this review, we provide an overview of the synaptic function of mitochondria and purines in neuromodulation, synaptic plasticity, and neuron-glia interactions. We summarize how mitochondrial and purinergic dysfunction contribute to mental illnesses such as schizophrenia, bipolar disorder, autism spectrum disorder (ASD), depression, and addiction. Finally, we discuss future implications regarding the pharmacological targeting of mitochondrial and purinergic function for the treatment of psychiatric disorders.

Styrene/Isoprene/Styrene Thermoplastic Elastomer Prepared by Anionic Bulk Polymerization in a Twin-Screw Extruder

In this study, a styrene/isoprene/styrene (SIS) triblock copolymer was synthesized in an intermeshing, co-rotating, twin-screw extruder. N-butyl lithium was used as the initiator. The styrene and isoprene monomer as well as 1,2-dibromoethane were sequentially added into the extruder. The weight content of isoprene in this copolymer was above 60%. Gel permeation chromatography (GPC) results showed that the polystyrene in the copolymer chains was mainly comprised of only one long block. Dynamic mechanical analysis (DMA) and transmission electron microscopy (TEM) showed that the polystyrene phase transferred from larger numbers of small microdomains to a continuous aggregation after the coupling reaction. As a result, the tensile stress and ultimate elongation was significantly improved, similar to the commercial product. Traditionally, SIS has only been synthesized by solution polymerization. The present work offers the capacity to synthesize it with very little or no solvent. This method fits the environmentally friendly trend.

Update on the neurobiology of schizophrenia: a role for extracellular microdomains

The glutamate system includes presynaptic glutamatergic terminals, complex post-synaptic densities found on diverse types of neurons expressing glutamate receptors, as well as glutamate transporters and enzymes that facilitate the glutamate/glutamine cycle. Abnormalities of this system have been implicated in schizophrenia based on an accumulating body of evidence from postmortem, imaging, and preclinical studies. However, recent work has suggested that astrocytes may have more than a bystander role in the synchronization of neuronal responses in the brain. Converging evidence suggests that extrasynaptic glutamate microdomains are formed by astrocytes and may facilitate neuroplasticity via the modulation of extra-synaptic glutamate receptors on neuronal membranes within these domains. In this article the authors propose that the composition and localization of protein complexes in glutamate microdomains is abnormal in schizophrenia, leading to pathological neuroplastic changes in the structure and function of glutamate circuits in this illness.

Disclosure of HIV-positive serostatus to sexual partners and associated factors in southern China

In light of an increased push for disclosure of HIV-positive serostatus to sexual partners (partner disclosure, PD) in China as reflected by national and local policies, the objective of this study was to determine the proportion and evaluate associated factors of PD among people living with HIV/AIDS (PLWHA) in HIV/AIDS high-risk areas in southern China. Of the 946 HIV-positive individuals, the proportion of those who disclosed positive serostatus results to their sexual partners was 90.2% (625/693). Variables independently associated with non-disclosure included testing in Guangxi province (adjusted relative ratio [ARR] = 0.33), becoming infected with HIV via injecting drug use (IDU) transmission (ARR = 0.32), having not reported discussing disclosure with health department staff during post-test counselling (ARR = 0.41) and having a sexual relationship of ≤2 years' duration (ARR = 0.31). This study also identified a relatively larger differential between the proportion of disclosure to regular partners and the proportion of disclosure to casual partners (94.8% versus 13.0%) in comparison with other studies. Findings from this study may aid policies for future consideration.

Frequency coding of positional information by an identified neuron, the AP cell, in the leech, Whitmania pigra

The synaptic connections from pressure-sensitive receptors (P cells) to identified neurons of unknown function (known as anterior pagoda or AP cells) were used to study the way in which leeches process information about the position of a mechanical stimulus on its skin. We elicited spikes in P cells by injecting current intracellularly while recording from AP neurons. The postsynaptic responses consisted of an increase in impulse frequency. We show here that the AP neuron can encode positional information in terms of the frequency of its action potentials. Thus, the AP neuron can serve as an indicator of integrative mechanisms used in the processing of sensory information that is important for the behavior of the animal.

Synergistic effects of the fenretinide (4-HPR) and anti-CD20 monoclonal antibodies on apoptosis induction of malignant human B cells

Retinoids have been shown to be clinically useful in the biological therapy of certain myeloid and T-cell malignancies, whereas CD20 has proven to be an effective target in B-cell lymphoma immunotherapy. Both retinoic acid derivatives and anti-CD20 monoclonal antibodies have also been shown to induce apoptosis of malignant cells in vitro. Retinoid-induced apoptosis is thought to be mediated by nuclear retinoid receptor binding and transcriptional activation, whereas CD20 ligation appears to initiate transmembrane Ca(2+) influx with resultant programmed cell death. In this report, we evaluate the in vitro effects of N-(4-hydroxyphenyl) retinamide (4-HPR) with and without anti-CD20 antibodies in B-cell lymphoma lines. We demonstrate that 4-HPR inhibits the growth of malignant B-cells beyond that of all-trans-retinoic acid and 13-cis-retinoic acid. We also show that this 4-HPR-mediated growth inhibition is attributable to apoptosis, is consistent across a variety of malignant B-cell lines (Ramos, Ramos AW, SU-DHL4, and Raji), peaks at 96 to 144 h, and is attainable with concentrations as low as 2 microM. As with CD20-mediated apoptosis, we show that the final common pathway includes caspase activation that can be blocked by 2-val-Ala-Asp-fluoromethyl ketone (z-VAD), a specific inhibitor of caspase function. Coincubation of a 2 microM concentration of 4-HPR and the anti-CD20 antibodies rituximab and tositumomab exhibited a supra-additive increase in levels of apoptosis induction of 24% (P = 0.009) and 42% (P = 0.0019) relative to expected additive levels of these same agents. These in vitro findings suggest that the potential in vivo synergy of these well-tolerated drugs may augment the previously demonstrated clinical activity of anti-CD20 monoclonal antibodies in the treatment of B-cell malignancies.

A facilitated cyclic ether formation and its potential application in solid-phase peptide and organic synthesis

A "trimethyl lock" system has been known to facilitate lactonization reactions through what has been termed a stereopopulation control mechanism. We have found that a similar trimethyl lock system can also facilitate cyclic ether formation with the concomitant release of a carboxylic acid in the presence of anhydrous tetrabutylammonium fluoride. To study this base-mediated trimethyl lock-facilitated cyclic ether formation, we synthesized fifteen model compounds. All model compounds underwent base-mediated cyclic ether formation in high yields at 0 degree C to room temperature (r.t.) with the concomitant release of the attached carboxylate. Such a system potentially could be used for the development of a two-dimensional linker for solid phase peptide and organic synthesis.

Characterization of scFv-Ig constructs generated from the anti-CD20 mAb 1F5 using linker peptides of varying lengths

The heavy (VH) and light (VL) chain variable regions of the murine anti-human CD20 mAb 1F5 were cloned, and four single-chain Ab (scFv) molecules were constructed using linker peptides of variable lengths to join the VH and VL domains. Three constructs were engineered using linker peptides of 15, 10, and 5 aa residues consisting of (GGGGS)3, (GGGGS)2, and (GGGGS)1 sequences, respectively, whereas the fourth was prepared by joining the VH and VL domains directly. Each construct was fused to a derivative of human IgG1 (hinge plus CH2 plus CH3) to facilitate purification using staphylococcal protein A. The aggregation and CD20 binding properties of these four 1F5 scFv-Ig derivatives produced were investigated. Both size-exclusion HPLC column analysis and Western blots of proteins subjected to nonreducing SDS-PAGE suggested that all four 1F5 scFv-Ig were monomeric with m.w. of approximately 55 kDa. The CD20 binding properties of the four 1F5 scFv-Ig were studied by ELISA and flow cytometry. The 1F5 scFv-Ig with the 5-aa linker (GS1) demonstrated significantly superior binding to CD20-expressing target cells, compared with the other scFv-Ig constructs. Scatchard analysis of the radiolabeled monovalent GS1 scFv-Ig revealed a binding avidity of 1.35 x 108 M-1 compared with an avidity of 7.56 x 108 M-1 for the native bivalent 1F5 Ab. These findings suggest that the GS1 scFv-Ig with a short linker peptide of approximately 5 aa is the best of the engineered constructs for future studies.

Involvement of mutations in the DPC4 promoter in endometrial carcinoma development

To define the target of chromosome 18q loss of heterozygosity, which is prevalent in endometrial carcinomas, we made a deletion map from 64 tumors. Loss of heterozygosity on 18q was found in 20 tumors. Among these, 14 tumors carried deletions at the 18q21.1 region, where the DPC4 gene is located. DPC4 transcription was disturbed in all six of the tumors with deletions at 18q21.1 examined, which sharply contrasted with the positive transcription in 12 tumors that retained heterozygosity at the 18q21.1 region. However, in the 14 tumors with the 18q21.1 deletions, the remaining allele had the wild-type sequence of the DPC4 coding region instead of somatic mutations in the DPC4 coding region. We found a one- and two-base substitutions in the DPC4 promoter in two of the six tumors that showed disturbed DPC4 transcription. Chloramphenicol acetyltransferase assays clearly demonstrated that the mutant promoters had the potential to suppress or silence DPC4 transcription, implicating the DPC4 gene in endometrial carcinoma.

Synthesis and evaluation of the physicochemical properties of esterase-sensitive cyclic prodrugs of opioid peptides using coumarinic acid and phenylpropionic acid linkers

In an attempt to improve the membrane permeabilities of opioid peptides, we have synthesized cyclic prodrugs of [Leu5]-enkephalin and DADLE using a coumarinic acid or a phenylpropionic acid linker. The synthesis of the coumarinic acid- and phenylpropionic acid-based cyclic prodrugs followed similar strategies. Key intermediates were the compounds with the C-terminal amino acids of opioid peptides (L-Leu, [Leu5]-enkephalin; D-Leu, DADLE) attached to the phenol hydroxyl group and the remaining amino acids of the peptide linked via the N-terminal amino acid (L-Tyr) attached to the carboxylic acid groups of the prodrug moieties (coumarinic acid or propionic acid). Cyclization of these linear precursors gave the cyclic prodrugs in 30-50% yields. These cyclic prodrugs exhibited excellent transcellular permeation characteristics across Caco-2 cell monolayers, an in vitro model of the intestinal mucosa. To correlate the cellular permeabilities of these cyclic prodrugs with their physicochemical properties, we calculated their Stokes-Einstein molecular radii from their diffusion coefficients which were determined by NMR and we determined their membrane interaction potentials using immobilized artificial membrane (IAM) column chromatography. The cyclic prodrugs exhibited molecular radii similar to those of the parent compounds, [Leu5]-enkephalin and DADLE. However, these cyclic prodrugs were shown to have much higher membrane interaction potentials than their corresponding opioid peptides. Therefore, the enhanced cellular permeation of the cyclic prodrugs is apparently due to the alteration of their lipophilicity and hydrogen bonding potential, but not their molecular sizes.

Coumarinic acid-based cyclic prodrugs of opioid peptides that exhibit metabolic stability to peptidases and excellent cellular permeability

To evaluate the cellular permeation characteristics and the chemical and enzymatic stability of coumarinic acid-based cyclic prodrugs 1 and 2 of the opioid peptides [Leu5]-enkephalin (H-Tyr-Gly-Gly-Phe-Leu-OH) and DADLE (H-Tyr-D-Ala-Gly-Phe-D-Leu-OH), respectively.

METHODS

The rates of conversion of the cyclic prodrugs 1 and 2 to [Leu5]-enkephalin and DADLE, respectively, in HBSS, pH 7.4 (Caco-2 cell transport buffer) and in various biological media having measurable esterase activity were determined by HPLC. The cell permeation characteristics of [Leu5]-enkephalin, DADLE and cyclic prodrugs 1 and 2 were measured using Caco-2 cell monolayers grown onto microporus membranes and monitored by HPLC.

RESULTS

In HBSS, pH 7.4, cyclic prodrugs 1 and 2 degraded chemically to intermediates that further degraded to [Leu5]-enkephalin and DADLE, respectively, in stoichiometric amounts. In 90% human plasma and rat liver homogenate, the disappearance of cyclic prodrugs 1 and 2 was significantly faster than in HBSS, pH 7.4. The half-lives in 90% human plasma and in rat liver homogenate were substantially longer after pretreatment with paraoxon, a known inhibitor of serine-dependent esterases. When applied to the AP side of a Caco-2 cell monolayer, cyclic prodrug 1 exhibited significantly greater stability against peptidase metabolism than did [Leu5]-enkephalin. Cyclic prodrug 2 and DADLE exhibited similar stability when applied to the AP side of the Caco-2 cell monolayer. Prodrug 1 was 665-fold more able to permeate the Caco-2 cell monolayers than was [Leu5]-enkephalin, in part because of its increased enzymatic stability. Prodrug 2 was shown to be approximately 31 fold more able to permeate a Caco-2 cell monolayer than was DADLE.

CONCLUSIONS

Cyclic prodrugs 1 and 2, prepared with the coumarinic acid promoiety, were substantially more able to permeate Caco-2 cell monolayers than were the corresponding opioid peptides. Prodrug 1 exhibited increased stability to peptidase metabolism compared to [Leu5]-enkephalin. In various biological media, the opioid peptides were released from the prodrugs by an esterase-catalyzed reaction, which is sensitive to paraoxon inhibition.

Apoptosis of malignant human B cells by ligation of CD20 with monoclonal antibodies

CD20 is a nonglycosylated 33 to 37 kD phosphoprotein involved in B-cell signaling that subserves important functions in the regulation of B-cell proliferation and differentiation. In addition, this B-cell surface antigen has been shown recently to be an effective target for immunotherapy of B-cell malignancies using chimeric (mouse/human) or radiolabeled murine monoclonal anti-CD20 antibodies. In this report we show that extensive crosslinking of CD20 with murine anti-CD20 monoclonal antibodies (MoAbs) in the presence of either goat anti-mouse IgG or Fc receptor (FcR)-expressing cells directly inhibits B-cell proliferation, induces nuclear DNA fragmentation, and leads to cell death by apoptosis. The apoptotic effects of these MoAbs can be inhibited by chelation of extracellular or intracellular Ca2+ by EGTA or Bapta AM, indicating that anti-CD20-mediated apoptosis may be related to changes in Ca2+ concentration. These findings suggest that ligation of CD20 in vivo by anti-CD20 antibodies in the presence of FcR-expressing cells may initiate signal transduction events that induce elevation of [Ca2+]i and lead to apoptosis of malignant B cells, thereby contributing to the impressive tumor regressions observed in mouse models and clinical trials using anti-CD20 MoAbs.

Prodrug strategies based on intramolecular cyclization reactions

Several new prodrug systems for amines, alcohols, and peptides are reviewed. The design of these new prodrug systems takes advantage of several facile intramolecular cyclization reactions, that permit separate manipulation of the release kinetics independent of the structural features of the drug moiety. Such systems can be used for the preparation of esterase-, phosphatase-, and redox-sensitive prodrugs of amines and alcohols and esterase-sensitive cyclic prodrugs of peptides and peptide mimetics.

Machado-Joseph disease: clinical, molecular, and metabolic characterization in Chinese kindreds

Machado-Joseph disease, an autosomal dominant multisystem motor degeneration, has been described mainly in people of Portuguese descent. Our report documents the presence of Machado-Joseph disease in the Chinese population, based on the specific molecular marker of a CAG repeat array in the 3' end of the MJD gene. We screened 21 Chinese families with dominant spinocerebellar ataxia. The results showed that Machado-Joseph disease with CAG expansion accounted for 52% of families with autosomal dominant cerebellar ataxia in this series. The clinical characteristics, besides the well-documented cerebellar ataxia, dysarthria, nystagmus, corticospinal dysfunctions, a variable degree of facial muscle fasciculation, and proprioceptive loss, included loss of optokinetic nystagmus and autonomic nervous system dysfunction. The CAG repeat number in the MJD gene ranged from 14 to 39 among normal alleles, and from 63 to 81 among MJD alleles. There was a strong inverse correlation (gamma = -0.77) between number of CAG repeats and age at symptom onset, accounting for 60% of the variance of age at onset. A strong clinical anticipation of age at onset existed in successive generations. Mild instabilities of expanded CAG repeat numbers during meiotic transmission occurred, with no significant difference according to the gender of the transmitting parent. Finally, brain metabolism in Machado-Joseph disease, studied with positron emission tomography, was characterized by significant progressive regional hypometabolism in the occipital cortex, as well as the cerebellar hemispheres, vermis, and brainstem.

Comparative metabolism and retention of iodine-125, yttrium-90, and indium-111 radioimmunoconjugates by cancer cells

Radiolabeled antibodies have produced encouraging remissions in patients with chemotherapy-resistant hematological malignancies; however, the selection of therapeutic radionuclides for clinical trials remains controversial. In this study, we compared the internalization, lysosomal targeting, metabolism, and cellular retention of radiolabeled murine and humanized monoclonal antibodies targeting the CD33 antigen (monoclonal antibodies mP67 and hP67, respectively) on myeloid leukemia cell lines (HEL and HL-60) and of anti-carcinoma antibodies (monoclonal antibodies hCTM01 and hA33) targeting breast cancer and colorectal carcinoma cell lines (MCF7 and Colo 205, respectively). Each antibody was labeled with 125I (by the IodoGen method) and with 111In and 90Y using macrocyclic chelation technology. Targeted tumor cells were analyzed for retention and metabolism of radioimmunoconjugates using cellular-radioimmunoassays, Percoll gradient fractionation of cell organelles, SDS-PAGE, and TLC of cell lysates and culture supernatants. Our results suggest that antibodies are routed to lysosomes after endocytosis, where they are proteolytically degraded. [125I]monoiodotyrosine is rapidly excreted from cells after lysosomal catabolism of antibodies radioiodinated by conventional methods, whereas small molecular weight 111In and 90Y catabolites remain trapped in lysosomes. As a consequence of the differential disposition of small molecular weight catabolites, 111In and 90Y conjugates displayed superior retention of radioactivity compared with 125I conjugates when tumor cells were targeted using rapidly internalizing antibody-antigen systems (e.g., hP67 with HEL cells and hCTM01 with MCF7 cells). When tumor cells were targeted using antibody-antigen systems exhibiting slow rates of endocytosis (e.g., hP67 on HL-60 cells and hA33 on Colo 205 cells), little differences in cellular retention of radioactivity was observed, regardless of whether 125I, 111In, or 90Y was used.

Constitutive endocytosis and degradation of CD22 by human B cells

The CD22 B lymphocyte-surface Ag is an important component of the B cell-surface IgM (sIgM)/B cell receptor complex and has been shown to regulate B cell activation. In addition, this molecule has been shown to be an effective target for immunotherapy of B cell malignancies using immunotoxins and radioimmunoconjugates. In this report we describe the internalization and metabolic degradation of this molecule under constitutive conditions and after stimulation of B cells with phorbol dibutyrate or mAbs binding to sIgM, CD19, and CD22. Flow cytometry, "neuraminidase protection," and "neuraminidase shift" assays demonstrated that CD22 is internalized constitutively by unstimulated B cell lines and subsequently degraded in an acidic intracellular compartment (presumably lysosomes) without detectable recycling of the molecule back to the cell surface. Ligation of CD22 with anti-CD22 mAbs markedly increased CD22 internalization but did not affect the rate of intracellular degradation of CD22, suggesting that anti-CD22 mAbs perturb the intracellular trafficking of CD22. In contrast, CD22 internalization and degradation was unaffected by stimulation of B cell lines with phorbol dibutyrate or ligation of other components of the B cell receptor complex (e.g. CD19, sIgM) with mAbs. These patterns of internalization and degradation under constitutive and stimulated conditions contrast with those reported for other lymphoid differentiation Ags (e.g., the TCR, CD3, CD4, and the transferrin receptor), and may help explain the utility of this molecule as a target for immunoconjugate therapy.

Constitutive endocytosis and degradation of CD22 by human B cells

The CD22 B lymphocyte-surface Ag is an important component of the B cell-surface IgM (sIgM)/B cell receptor complex and has been shown to regulate B cell activation. In addition, this molecule has been shown to be an effective target for immunotherapy of B cell malignancies using immunotoxins and radioimmunoconjugates. In this report we describe the internalization and metabolic degradation of this molecule under constitutive conditions and after stimulation of B cells with phorbol dibutyrate or mAbs binding to sIgM, CD19, and CD22. Flow cytometry, "neuraminidase protection," and "neuraminidase shift" assays demonstrated that CD22 is internalized constitutively by unstimulated B cell lines and subsequently degraded in an acidic intracellular compartment (presumably lysosomes) without detectable recycling of the molecule back to the cell surface. Ligation of CD22 with anti-CD22 mAbs markedly increased CD22 internalization but did not affect the rate of intracellular degradation of CD22, suggesting that anti-CD22 mAbs perturb the intracellular trafficking of CD22. In contrast, CD22 internalization and degradation was unaffected by stimulation of B cell lines with phorbol dibutyrate or ligation of other components of the B cell receptor complex (e.g. CD19, sIgM) with mAbs. These patterns of internalization and degradation under constitutive and stimulated conditions contrast with those reported for other lymphoid differentiation Ags (e.g., the TCR, CD3, CD4, and the transferrin receptor), and may help explain the utility of this molecule as a target for immunoconjugate therapy.

Nerve growth factor and neuronal cell death

The regulation of neuronal cell death by the neuronotrophic factor, nerve growth factor (NGF), has been described during neural development and following injury to the nervous system. Also, reduced NGF activity has been reported for the aged NGF-responsive neurons of the sympathetic nervous system and cholinergic regions of the central nervous system (CNS) in aged rodents and man. Although there is some knowledge of the molecular structure of the NGF and its receptor, less is known as to the mechanism of action of NGF. Here, a possible role for NGF in the regulation of oxidant--antioxidant balance is discussed as part of a molecular explanation for the known effects of NGF on neuronal survival during development, after injury, and in the aged CNS.