[Treatment of palbociclib in hormone receptor positive breast cancer: a real-world study and efficacy prediction model]

Objective: To summarize the clinical use of palbociclib and evaluate its efficacy and safety in hormone-receptor (HR)-positive advanced breast cancer patients. Methods: We retrospectively analyzed data from 66 HR-positive metastatic breast cancer patients treated with palbociclib and endocrine therapy at the Department of Oncology in the First Affiliated Hospital with Nanjing Medical University between 2018 and 2020. We evaluated the factors affecting the efficacy of palbociclib using Kaplan-Meier method and Log-rank test for survival analysis and Cox regressions for multivariate analysis. Nomogram model was built for predicting prognosis among HR-positive breast cancer patients who received palbociclib. Concordance index (C-index) and calibration curve were used for internal validation to assess the predictive ability and conformity of the model. Results: Of the 66 patients treated with palbociclib, 33.3%(22), 42.4%(28) and 24.2%(16) patients were treated without endocrine therapy, first-line endocrine therapy, second-line or above endocrine therapy after recurrence, respectively. 36.4%(24) patients had hepatic metastasis, 16.7% (11) patients were sensitive to previous endocrine therapy, 27.3%(18/66) patients had primary resistance to endocrine therapy, while 56.1% (37) patients had secondary resistance to endocrine therapy. The overall response rate was 14.3% (95% CI: 6.7%, 25.4%) and clinical benefit rate was 58.7% (95% CI: 45.6%, 71.0%). Better clinical outcomes were associated with non-hepatic metastasis (P=0.001), sensitive/secondary resistant to previous endocrine therapy (P=0.004), no or only one line of chemotherapy for metastatic breast cancer (P=0.004), recent pathological confirmation of immunohistochemical analysis (P=0.025). Hepatic metastasis (P=0.005) and primary resistance to endocrine therapy (P=0.016) were the independent risk factors of progression free survival. The C-index of predictive probability for the nomogram constructed from the patient clinical characteristics (whether liver metastasis, whether primary endocrine resistance, lines of chemotherapy after metastasis, lines of endocrine therapy, number of metastatic sites, and time to last immunohistochemistry) to predict the progression-free survival at 6 and 12 months for patients was 69.7% and 72.1%, respectively. The most common adverse events were hematologic toxicities. Conclusions: Our report indicates that palbociclib combined with endocrine therapy for HR-positive recurrent metastatic breast cancer is effective and safe; patients with hepatic metastases and primary resistance to endocrine therapy have worse prognoses and are independent risk factors for progression after palbociclib therapy. The constructed nomogram could help predict the survival and guide the use of palbociclib.

[A real-world study on the efficacy and safety analysis of paclitaxel liposome in advanced breast cancer]

Objective: To explore the application and efficacy of paclitaxel liposome in the treatment of advanced breast cancer among Chinese population in the real world. Methods: The clinical characteristics of patients with advanced breast cancer who received paclitaxel liposome as salvage treatment from January 1, 2016 to August 31, 2019 in 11 hospitals were collected and retrospectively analyzed. The primary outcome was progression free survival (PFS), and the secondary outcome included objective response rate (ORR) and safety. The survival curve was drawn by Kaplan-Meier analysis and the Cox regression model were used for the multivariate analysis. Results: Among 647 patients with advanced breast cancer who received paclitaxel liposome, the first-line treatment accounted for 43.3% (280/647), the second-line treatment accounted for 27.7% (179/647), and the third-line and above treatment accounted for 29.1% (188/647). The median dose of first-line and second-line treatment was 260 mg per cycle, and 240 mg in third line and above treatment. The median period of paclitaxel liposome alone and combined chemotherapy or targeted therapy is 4 cycles and 6 cycles, respectively. In the whole group, 167 patients (25.8%) were treated with paclitaxel liposome combined with capecitabine±trastuzumab (TX±H), 123 patients (19.0%) were treated with paclitaxel liposome alone (T), and 119 patients (18.4%) were treated with paclitaxel liposome combined with platinum ± trastuzumab (TP±H), 108 patients (16.7%) were treated with paclitaxel liposome combined with trastuzumab ± pertuzumab (TH±P). The median PFS of first-line and second-line patients (5.5 and 5.5 months, respectively) were longer than that of patients treated with third line and above (4.9 months, P<0.05); The ORR of the first line, second line, third line and above patients were 46.7%, 36.8% and 28.2%, respectively. Multivariate analysis showed that event-free survival (EFS) and the number of treatment lines were independent prognostic factors for PFS. The common adverse events were myelosuppression, gastrointestinal reactions, hand foot syndrome and abnormal liver function. Conclusion: Paclitaxel liposomes is widely used and has promising efficacy in multi-subtype advanced breast cancer.

[A descriptive analysis of tea consumption in adult twins in China]

Objective: To describe the distribution characteristics of tea consumption in adult twins recruited in the Chinese National Twin Registry (CNTR) and provide clues to genetic and environmental influences on tea consumption. Methods: Enrolled in CNTR during 2010-2018, 25 264 twin pairs aged 18 years and above were included in subsequent analysis. Random effect models were used to estimate tea consumption in the population and regional distribution characteristics. The concordance rate of the behavior and difference in consumption volume of tea within pairs were also described. Results: The mean age of all subjects was (35.38±12.45) years old. The weekly tea consumers accounted for 17.0%, with an average tea consumption of (3.36±2.44) cups per day. The proportion of weekly tea consumers was higher among males, 50-59 years old, southern, urban, educated, and the first-born in the twin pair (P<0.05), and lower among unmarried individuals (P<0.001). Within-pair analysis showed that the concordance rate of tea consumption of monozygotic (MZ) twins was higher than that of dizygotic (DZ) twins and the overall heritability of tea consumption was 13.45% (11.38%-15.51%). Stratified by the characteristics mentioned above, only in males, the concordance rate of MZ showed a tendency to be greater than that of DZ (all P<0.05). The differences in consumption volume of tea within twin pairs were minor in MZ among males (P<0.05), while the differences were not significant in female twins. Conclusion: There were discrepancies in the distribution of tea consumption among twins of different demographic and regional characteristics. Tea consumption was mainly influenced by environmental factors and slightly influenced by genetic factors. The size of genetic factors varied with gender, age, and region, and gender was a potential modified factor.

[A descriptive analysis on coronary heart disease in adult twins in China]

Objective: To describe the distribution characteristics of coronary heart disease in adult twins recruited from Chinese Twin Registry (CNTR), and provide clues and evidence for the effect of genetic and environmental influences on coronary heart disease. Methods: By using the data of CNTR during 2010-2018, a total of 34 583 twin pairs aged ≥18 years who completed questionnaire survey and had related information were included in the current study to analyze the population and area distribution characteristics of coronary heart disease. Random effect models were used to compare the differences between groups. The concordane rate of coronary heart disease were calculated respectively in monozygotic (MZ) twin pairs and dizygotic (DZ) twin pairs to estimate the heritability. Results: The twin pairs included in this analysis were aged (34.2±12.4) years. The overall prevalence rate of coronary heart disease in twin pairs was 0.7%. Twin pairs who were women, older, obese and lived in northern China had higher prevalence of coronary heart disease (P<0.05). Intra-pair analysis in the same-sex twin pairs found that the concordane rate of coronary heart disease was higher in MZ twin pairs (25.3%) than in DZ twins (7.4%), and the difference was statistically significant (P<0.001). The overall heritability of coronary heart disease was 19.3% (95%CI: 11.8%-26.8%). Stratified by gender, age and area, the concordane rate was still higher in MZ twin pairs than in DZ pairs. Participants who were women, aged 18-30 years or ≥60 years and lived in northern China had a higher heritability of coronary heart disease. Conclusion: The distribution of coronary heart disease in twin pairs differed in populations and areas. The prevalence of coronary heart disease was affected by genetic factors, but the effect varied with age, gender and area.

[A descriptive analysis on type 2 diabetes in twins in China]

Objective: To describe the distribution characteristics of type 2 diabetes in twins in Chinese National Twin Registry (CNTR), provide clues and evidence for revealing the influence of genetic and environmental factors for type 2 diabetes. Methods: Of all twins registered in the CNTR during 2010-2018, a total 18 855 twin pairs aged ≥30 years with complete registration information were included in the analysis. The random effect model was used to describe the population and area distribution characteristics and concordance of type 2 diabetes in twin pairs. Results: The mean age of the subjects was (42.8±10.2) years, the study subjects included 10 339 monozygotic (MZ) twin pairs and 8 516 dizygotic (DZ) twin pairs. The self-reported prevalence rate of type 2 diabetes was 2.2% in total population and there was no sighificant difference between MZ and DZ. Intra-twin pairs analysis showed that the concordance rate of type 2 diabetes was 38.2% in MZ twin pairs, and 16.0% in DZ twin pairs, the difference was statistically significant (P<0.001). The concordance rate of type 2 diabetes in MZ twin parts was higher than that in DZ twin pairs in both men and women, in different age groups and in different areas (P<0.05). Further stratified analysis showed that in northern China, only MZ twin pairs less than 60 years old were found to have a higher concordance rate of type 2 diabetes compared with DZ twin pairs (P<0.05). In southern China, the co-prevalence rate in male MZ twin pairs aged ≥60 years was still higher than that in DZ twin pairs (P<0.05). Conclusion: The twin pairs in this study had a lower self-reported prevalence of type 2 diabetes than the general population. The study results suggested that genetic factors play a role in type 2 diabetes prevalence in both men and women, in different age groups and in different areas, however, the effect might vary.

MiR-181a promotes cell proliferation and migration through targeting KLF15 in papillary thyroid cancer

INTRODUCTION

Papillary thyroid cancer (PTC) is the predominant histological type of thyroid cancer, accounting for 80% of thyroid cancers. MiR-181a is a novel microRNA that is usually upregulated in multiple cancers. This study aims to explore the role and underlying mechanism of miR-181a in PTC.

METHODS

CCK8 and Transwell assays were performed to evaluate cell viability and migration. The mRNA level of miR-181a and KLF15 was calculated by qRT-PCR. The protein level of E-Cadherin, N-Cadherin and GAPDH was evaluated by western blot. Dual luciferase assay was conducted to validate that miR-181a directly targeting the 3'-UTR of KLF15 mRNA in TPC-1 cells.

RESULTS

We observed that miR-181a was overexpressed and KLF15 was low expressed in PTC tissues and cell lines. Upregulation of miR-181a or downregulation of KLF15 predicted poor outcomes in PTC patients. MiR-181a improved cell growth of PTC, migration and epithelial-mesenchymal transition (EMT) in TPC-1 cells. KLF15 was a target gene of miR-181a and its expression was mediated by miR-181a. KLF15 partially reversed the facilitating effect of miR-181a on cell proliferation and migration in TPC-1 cells.

CONCLUSION

We discovered that miR-181a served as an oncogene downregulating KLF15, thereby inhibiting cell proliferation, migration and the EMT. These findings demonstrate that miR-181a plays a significant role in PTC progression and could be a therapeutic target for PTC.

[Analysis on prevention and control of some infectious diseases in the elderly aged 60 years and above in China and countermeasure recommendation]

As the progress of population aging in China, the proportion of elderly population is increasing. Both chronic diseases and infectious diseases can threaten the health of the elderly. There are many kinds of infectious diseases, including vaccine preventable infectious diseases affecting the health of adults, such as influenza, pneumococcal diseases and herpes zoster. In addition, the newly emerged COVID-19 has caused a pandemic in the world, resulting the highest proportion of deaths occurred in the elderly and posing a serious threat to the health of the elderly. This paper mainly summarizes the prevention and control of vaccine preventable diseases and COVID-19 to which the elderly are susceptible, analyzes the infectious disease problems affecting the health of elderly population, and recommends countermeasures for the prevention and control of these diseases in elderly population.

Nitrogen utilisation and metabolism in maize (Zea mays L.) plants under different rates of biochar addition and nitrogen input conditions

Biochar (BC) application could improve plant nitrogen (N) utilisation and potentially reduce N fertiliser requirements. However, the fate of N in crop-soil systems and the metabolic responses of crops under conditions of BC co-applied with reduced N are not well understood. The urea-¹⁵ N isotope and pot experiments with three BC rates (0%, 5% and 15%; w/w) combined with three N fertiliser levels (100% N, 85% N and 55% N) were conducted for maize. The metabolome, ¹⁵ N abundance and gene expression in plants were analysed using nuclear magnetic resonance, gas isotope mass spectrometry and quantitative real-time reverse transcription PCR, respectively. The results showed that recovery of N by maize ranged from 27.4% to 23.6% and decreased as the N application rate decreased (from 100% to 55%) without BC addition, but ranged from 24.6% to 29.4% when BC was added at a rate of 5% and increased as the N application rate decreased. BC addition had major effects on global metabolic profiles and metabolic networks at the metabolomics level as well as on the expression of related genes (zmGS1and zmAS1) and the content of mineral N (NO₃ ^- , NO₂ ^- and NH₄ ⁺ ) in maize seedlings; moreover, the interaction effects of the BC application rates and N fertiliser levels were evident (P ≤ 0.001). BC addition induced a decrease in the flux toward sugar hydrolysis and maintained homeostasis in the amino acid pool, which was perturbed by reduced N levels; after which the maize plants adapted to the reduced N condition, and the N recovery efficiency ultimately improved with reduced N loss.

[Outcomes of splenectomy in relapsed/refractory autoimmune hemolytic anemia]

Objective: To evaluate the outcomes of splenectomy in the treatment of relapsed/refractory autoimmune hemolytic anemia (AIHA). Methods: Retrospective analysis was performed in 30 cases with relapsed/refractory AIHA who were treated with splenectomy in our hospital. The pre- and post-operative blood routine indexes and responses were followed up. Results: Among the 30 relapsed/refractory AIHA patients, 20 were pure AIHA (including 13 patients with warm antibody AIHA, 2 with warm-cold double antibody AIHA and 5 with Coombs negative AIHA) and 10 were Evans syndrome. The short-term response was evaluated 10-14 days after operation, and the overall response rate (ORR) of short-term response was 90% [12 cases in complete response (CR), 6 cases in partial response (PR)] in 20 therapeutic evaluable cases. Among 13 patients with long-term follow-up data, except 3 patients with Evans syndrome died (2 cases were refractory to splenectomy, 1 case relapsed after surgery), the ORR of 10 patients with relapsed/refractory pure AIHA at 6 months and 12 months were 90% (9/10) and 70% (7/10), respectively, with a median follow-up of 14 (4-156) months. At the end of follow-up, 3 cases had maintained CR for more than 3 years. Conclusion: The short-term response of splenectomy as a second-line treatment for relapsed/refractory AIHA is satisfactory, and long-term outcome of splenectomy is up to 70% at 1 year. Approximately one-third of patients could maintain sustained remission.

[Mediating effect of work engagement between job stress and depressive symptoms in State Grid employees]

Objective: To explore the relationship between job stress, work engagement and depressive symptoms of State Grid workers, and to analyze the mediating effect of work engagement between job stress and depressive symptoms. Methods: A cross-sectional survey was conducted to investigate 845 employees from a State Grid company, using the brief job stress questionnaire, the Patient Health Questionnaire (PHQ-9) and 9-item Utrecht Work Engagement Scale (UWES-9) in March 2017. Results: The average score of work engagement was 4.49±1.42, the mean value of job stress was 1.15±0.33, the average score of depressive symptoms was 6.44±4.30, and the positive rate of depressive symptoms was 66.9%.There was a negative correlation between work engagement with both job stress and depressive symptoms (r=-0.193, -0.397, both P<0.01) , and job stress was positively correlated with depressive symptoms (r=0.260, P<0.01) . The relationship between job stress and depressive symptoms was partly mediated by work engagement, and the mediating effect accounted for 27.2% of the total effect. Conclusion: The work engagement of State Grid staff acts as the mediator between job stress and depressive symptoms, alleviating the depressive symptoms caused by job stress.

[Association between Long Working Hours and Job Stress and Depression among Employees from a State Grid Company]

Objective: This study was to understand the current situation of long working hours and identify the association of long working hours and job stress and depression among workers from one district company of state grid. Methods: The project was done with the cross-sectional survey. All questionnaires were completed by self-administered with informed consent. Employees' weekly working hours was reported by themselves; Using the PHQ-9 scale to assess depression, the JDC Model to evaluate job stress, and SPSS software to analyze data, the single factor chi-square test and multivariate Logistic analysis were performed to identify the association between long working hours and job stress, depression. Results: there were 35.3 percent employees with over 44 hours a week. The association between increasing weekly working hours and job stress and depression was statistically significant. Compared to the reference group (≤44 h) , for those who worked more than 44 hours per week, the odds ratio of job stress was 2.02 (95%CI=1.27-3.23) times increased, and the odds ratio of depression was 1.60 (95%CI=1.01-2.55) times increased, especially for those (≥60 h) , the odds ratio was 3.69 (95%CI=1.45-9.41) and 2.76 (95%CI=1.09-7.03) respectively. Conclusion: Long working hours can significantly increase the risk of job stress and depression among workers. When their weekly working hours exceeds 60, long working hours will be the independent risk factor for both job stress and depression.

Plastic responses in the metabolome and functional traits of maize plants to temperature variations

Environmentally inducible phenotypic plasticity is a major player in plant responses to climate change. However, metabolic responses and their role in determining the phenotypic plasticity of plants that are subjected to temperature variations remain poorly understood. The metabolomic profiles and metabolite levels in the leaves of three maize inbred lines grown in different temperature conditions were examined with a nuclear magnetic resonance metabolomic technique. The relationship of functional traits to metabolome profiles and the metabolic mechanism underlying temperature variations were then explored. A comparative analysis showed that during heat and cold stress, maize plants shared common plastic responses in biomass accumulation, carbon, nitrogen, sugars, some amino acids and compatible solutes. We also found that the plastic response of maize plants to heat stress was different from that under cold stress, mainly involving biomass allocation, shikimate and its aromatic amino acid derivatives, and other non-polar metabolites. The plastic responsiveness of functional traits of maize lines to temperature variations was low, while the metabolic responsiveness in plasticity was high, indicating that functional and metabolic plasticity may play different roles in maize plant adaptation to temperature variations. A linear regression analysis revealed that the maize lines could adapt to growth temperature variations through the interrelation of plastic responses in the metabolomes and functional traits, such as biomass allocation and the status of carbon and nitrogen. We provide valuable insight into the plastic response strategy of maize plants to temperature variations that will permit the optimisation of crop cultivation in an increasingly variable environment.

Metabolic response of maize plants to multi-factorial abiotic stresses

Clarification of the metabolic mechanisms underlying multi-stress responses in plants will allow further optimisation of crop breeding and cultivation to obtain high yields in an increasingly variable environment. Using NMR metabolomic techniques, we examined the metabolic responses of maize plants grown under different conditions: soil drought, soil salinity, heat and multiple concurrent stresses. A detailed time-course metabolic profile was also performed on maize plants sampled 1, 3 and 7 days after initiation of soil drought and heat stress. The metabolic profile of maize plants subjected to soil drought was more similar to plants exposed to salt stress than to heat-stressed plants. Drought-stressed maize plants subjected to salt or heat stress showed distinct integrated metabolic profiles compared with those exposed to either stressor individually. These differences show the considerable metabolic plasticity of maize in response to different growth conditions. Moreover, glucose, fructose, malate, citrate, proline, alanine, aspartate, asparagine, threonine and one unknown compound fluctuated obviously between maize plants grown in controlled growth cabinet and a natural regime. These changes were associated with the TCA cycle and core nitrogen metabolism, and could be related to their multiple functions during plant growth. The evident stress-induced trajectory of metabolic changes in maize indicated that the primary metabolic responses to soil drought, heat and combined drought and heat stresses occurred in a time-dependent manner. Plasticity at the metabolic level may allow maize plants to acclimatise their metabolic ranges in response to changing environmental conditions.

Designed fabrication of anatase mesocrystals constructed from crystallographically oriented nanocrystals for improved photocatalytic activity

In this article, we report a new route to synthesize octahedral anatase mesocrystals (MCs), polycrystals (PCs) and single crystals (SCs) in the TiCl₄–CH₃COOH system just by tuning the reaction time and Ti-source concentration.

Oxidative degradation of propachlor by ferrous and copper ion activated persulfate

The process of in situ chemical oxidation (ISCO) by persulfate (S(2)O(8)(2-)) can be accelerated by metal ion activation, which more effectively degrades subsurface pollutants by enhancing sulfate radical (SO(4)(-)) generation. This study compared the results of propachlor degradation by Cu(2+) and Fe(2+) activated persulfate and revealed differing degradation kinetics and mechanisms between the two types of activation system. The activation of persulfate by Fe(2+) ions generally resulted in rapid degradation in the early stage, but was accompanied by a dramatic decrease in efficiency due to the rapid depletion of Fe(2+) by the sulfate radicals generated. In contrast, the Cu(2+) activated persulfate had a longer lasting degradation effect and a proportionally greater degradation enhancement at elevated Cu(2+) concentrations. An optimal Fe(2+) concentration should be sought to activate the persulfate, as a high Fe(2+) concentration of 2.5mM or above, as was used in this study, may inhibit propachlor degradation due to the competitive consumption of sulfate radicals by the excess Fe(2+) ions. Higher temperatures (55°C compared with 30°C) resulted in enhanced metal activation, particularly with the Cu(2+) activated system. Furthermore, acidic conditions were found to be more favorable for propachlor degradation by metal activated persulfate. The ecotoxicity of degraded propachlor samples, which was indicated by average well color development (AWCD) for its microbial community activity, was confirmed to be decreased during the degradation processes with these two ions activated persulfate.

Electrooxidation of Methanol on upd-Ru and upd-Sn Modified Pt Electrodes

The electrochemical oxidation of methanol has been investigated on underpotentially deposited-ruthenium-modified platinum electrode (upd-Ru/Pt) and on underpotentially deposited-tin-modified platinum electrode (upd-Sn/Pt). The submonolayers of upd-Ru and upd-Sn on a Pt electrode increased the rate of methanol electrooxidation several times as large as that on a pure Pt electrode. The best performance for methanol electrooxidation was obtained on a ternary platinum based catalyst modified by upd-Ru and upd-Sn simultaneously. The influence of the submonolayers of upd-Ru adatoms and upd-Sn adatoms on the oxidation of methanol in acid has been investigated. The effect of Ru on methanol electrooxidation lies on the distribution of Ru adatoms on a Pt surface. It has been shown that as long as the amount of upd-Ru deposits were controlled in a proper range, upd-Ru deposits would enhance the methanol oxidation obtained on a Pt electrode at whichever deposition potential the upd-Ru deposits were obtained. The effects of tin are sensible to the potential range. The enhancement effect of upd-Sn adatoms for the oxidation of methanol will disappear as the electrode potential is beyond a certain value. It is speculated that there exists a synergetic effect on the Pt electrode as adatoms Ru and Sn participate simultaneously in the methanol oxidation.

The biological behaviour of human adenoid cystic carcinoma cells transduced with interleukin-2-gene

Adenoid cystic carcinoma (ACC) of the salivary glands is a highly infiltrative malignant tumour with a tendency for lung metastasis. Gene therapy could be a potentially effective therapy for ACC and its metastasis. The aims of the study were: To transduce interleukin-2 (IL-2) gene into an ACC cell line with predisposition for lung metastasis (ACC-M); to compare the bioactivity of the gene-transduced cells and the parent cell line in vitro and in vivo. The IL-2 gene was transduced via a bicistronic retroviral vector into the ACC-M cells. The growth rate and DNA cell cycles of the parent ACC-M, the control viral vector AmGCEN, and the gene transduced AmIL-2 cell cultures were compared quantitatively and by flow cytometry, respectively. The tumourigenic ability of the three cell lines was verified by inoculation in athymic nude mice. The tumours developed were extracted and compared quantitatively and histologically. There was no difference in the growth rate and the DNA count between the ACC-M, AmGCEN, and AmIL-2 cell cultures. In the animal experiment, both the ACC-M and AmGCEN cells stimulated lung metastasis in all the mice, whereas there was no tumour found in the 1 x 10(6) AmIL-2 cells inoculation. On 3 x 10(6) AmIL-2 cells stimulation, three out of six mice developed tumours but the mass and volume of the tumours were smaller than the other two groups. Under light microscopy, the ACC-M tumours were mainly poorly differentiated with minimal cellular matrix, whereas the AmIL-2 tumours were well differentiated with ample matrix. The transduction of IL-2 gene can reduce the tumourigenicity of ACC-M cells and induces tumour cell differentiation in mice. The IL-2 gene can be a potential effective gene for the treatment of adenoid cystic carcinoma of salivary glands and its lung metastasis.

Cloning and identification of differentially expressed transcripts in primary culture of GABAergic neurons

A RNA based arbitrarily primed polymerase chain reaction (RAP-PCR) was used to identify differentially expressed transcripts in primary cultures of cerebral cortical neurons prepared from E16 mouse cerebral cortex. The majority of neurons found in this culture preparation are known to be GABAergic. Different primer combinations were used, and the PCR products were separated on PAGE. Visualization by silver staining revealed a high resolution RNA fingerprint pattern with a total of about 200 transcripts. Six differentially expressed cDNA fragments were recovered, cloned and sequenced. The results of a NCBI database search showed that 6 clones were highly homologous to known genes and expressed sequence tags (ESTs), and that they were either up-regulated or down-regulated during development. Among these clones, Clone 3.1.7 shared 99% sequence homology to mouse Reelin, a neuronal migration and positioning related protein. Clone 4.6.2 shared 91% homology to Rat prepro bone morphogenetic protein-3 mRNA. Clone 6.10.2 had 90% homology to a novel orphan gene of calcium-independent alpha-latrotoxin receptor, which stimulates presynaptic neurotransmitter release. Northern blot analysis confirmed the up-regulated expression profile of Clone 6.10.2 in neuron from Day 2 to 7 during stages of differentiation and development.

The NF2 interactor, hepatocyte growth factor-regulated tyrosine kinase substrate (HRS), associates with merlin in the "open" conformation and suppresses cell growth and motility

The neurofibromatosis 2 tumor suppressor protein, merlin or schwannomin, functions as a negative growth regulator; however, its mechanism of action is not known. In an effort to determine how merlin regulates cell growth, we analyzed a recently identified novel merlin interactor, hepatocyte growth factor-regulated tyrosine kinase substrate (HRS). We demonstrate that regulated overexpression of HRS in rat schwannoma cells results in similar effects as overexpression of merlin, including growth inhibition, decreased motility and abnormalities in cell spreading. Previously, we showed that merlin forms an intramolecular association between the N- and C-termini and exists in "open" and "closed" conformations. Merlin interacts with HRS in the unfolded, or open, conformation. This HRS binding domain maps to merlin residues 453-557. Overexpression of C-terminal merlin has no effect on HRS function, arguing that merlin binding to HRS does not negatively regulate HRS growth suppressor activity. These results suggest the possibility that merlin and HRS may regulate cell growth in schwannoma cells through interacting pathways.

[A brief introduction to the methods for novel gene cloning]

There are a lot of methods for novel gene cloning, but how to clone candidate gene(s) quickly and correctly? This is a brief introduction to methods of novel gene cloning, these methods includes: differential display reverse transcriptase polymerase chain reaction(DD RT-PCR), suppression subtractive hybridization(SSH), RNA arbitrarily primed PCR(RAP-PCR), representational difference analysis(RDA), yeast two-hybrid system, cDNA capturation, et al. We not only introduced these methods, but also discussed the advantages and disadvantages of them. However, no single method is omnipotent, one should pick up the method most suitable for a special purpose.

Antibacterial peptides from pig intestine: isolation of a mammalian cecropin

Pig small intestine was used as starting material for a batchwise isolation of a peptide fraction enriched in antibacterial activities against Escherichia coli (anti-Ec factor) and against Bacillus megaterium (anti-Bm factor). Separation and further purification were by different types of chromatography. Sequence analysis showed the anti-Bm factor to be apparently similar to vasoactive intestinal peptide. The anti-Ec factor was found to have a 31-residue sequence that was cecropin-like. It was named cecropin P1 and its structure was confirmed by solid-phase synthesis. Synthetic cecropin P1 with and without C-terminal amide was assayed on eight different bacteria. Mobility comparison between synthetic and natural cecropin P1 indicates that the natural peptide has a free C-terminal carboxyl group.