[A study on the end criteria of forced vital capacity curve in adults].

Objective: To explore the end criteria of forced vital capacity(FVC) curve in adults. Methods: A multicenter cross-sectional study was performed in Zhongshan Hospital Affiliated to Fudan University, the First Affiliated Hospital of Fujian Medical University, and the Third Affiliated Hospital of Inner Mongolia Medical University from January 2017 to August 2017. A consecutive sample of subjects who completed the spirometry test and FVC curves met end criteria of no volume change (<0.025 L) for ≥ 1 s were qualified in this study. Subjects were divided into a normal group (n=610), an obstructive group (n=536), and a restrictive group(n=306) according to pulmonary function test results. The FET values in different groups were compared. The side effects in the 3 groups and the diagnostic accuracy, specificity and security of different FET in the obstructive group were assessed. Results: The FET values of the normal group, the obstructive group, and the restricted group were (4.00±1.07) s, (8.08±1.56) s and (2.97±0.76) s respectively, and the 95% CI of FET in the 3 groups were between 3.88-4.12 s, 7.02-10.14 and 2.21- 3.73 s (F=2 263.80, P<0.01). When the exhalation platform was used as the standard of FVC curve, the adverse reaction rate in the normal group and the restricted group were 1.1% and 1.3% respectively, lower than the rate of 17.2% in the obstructive group (χ(2)=92.73, χ(2)=48.49 respectively; all P<0.05). In the obstructive group, 7 s as the ending criterion had similar incidence of adverse reactions to 6 s (χ(2)=0.01, P=0.93). With further extension of expiration time, the incidence of adverse reactions increased significantly. In the obstructive group, the sensitivity of FEV(1)/FEV(7) was 99.25%, higher than that at FEV(1)/FEV(6) (χ(2)=4.06, P=0.04), and the specificity of diagnosis was very similar and 100%. Conclusions: FET was variable in subjects with different lung function status. It is not appropriate to use a fixed FET≥ 6 s as the end criterion of spirometry for adults. For patients with normal lung function or restrictive lung function defect, exhalation platform should be used as the end of exhalation standard. For patients with obstructive lung function defect, an FET of up to 7 s is appropriate.

[The inhibition effects of apatinib on cell proliferation, migration and apoptosis in esophageal carcinoma via Ras/Raf/MEK/ERK and JAK2/STAT3 pathways].

Objective: To investigate the in vitro and in vivo effects of apatinib in esophageal squamous cell carcinoma and the underlying mechanisms. Methods: The esophageal cancer cells, KYSE-150 and ECA-109, were divided into control group and apatinib treatment group at the concentrations of 2.5, 5, 10, 20 and 40 µmol/L respectively. All of experiments were performed in triplicate. MTT and colony formation assays were used to measure cell proliferation. Transwell assay was used to determine the migration capacity. The effect of apatinib on cell cycle and apoptosis was analyzed by flow cytometry. The expression of VEGF and VEGFR-2 was measured by real-time quantitative PCR (qRT-PCR). The concentration of VEGF in the cell supernatant was assessed by enzyme-linked immunosorbent assay (ELISA). The expression levels of MEK, ERK, p-MEK, p-ERK, JAK2, STAT3 and p-STAT3 after VEGF stimulation were detected by Western blot. Furthermore, the nude mice xenograft model was established. The tumor-bearing mice were randomly divided into control group, apatinib low dose treatment group (250 mg) and apatinib high dose treatment group (500 mg), respectively. Tumor inhibition rates of different groups were calculated. And then the expressions of VEGF and VEGFR2 were detected in xenograft tissues by immunohistochemical staining. Results: In the presence of 20 µmol/L and 40 µmol/L of apatinib for 24 hours, the migration cell numbers of KYSE-150 and ECA-109 were 428.67±4.16 and 286.67±1.53 as well as 1 123.67±70.00 and 477.33±26.84, respectively, that were significantly lower than control group (P<0.05 for all). In addition, after treatment with 10 µmol/L, 20 µmol/L and 40 µmol/L of apatinib for 7 days on KYSE-150 and ECA-109, the colony formation rates were (65.12±25.48)%, (58.19±24.73)% and (29.10±22.40)% as well as (70.61±15.14)%, (61.12±17.21)% and (43.09±11.13)%, respectively. The colony formation rates of 20 µmol/L and 40 µmol/L of apatinib treatment groups were significantly lower than control group (100.00±0.00, P<0.05). The cell cycle ratio of G(2)/M phase and apoptosis rate of control group and 20 µmol/L apatinib group in KYSE-150 cells were (12.14±2.13)% and (3.49±0.74)% as well as (26.27±3.30)% and (15.65±1.54)%, respectively. The corresponding ratios in ECA-109 cells were (3.44±0.57)% and (6.31±1.43)% as well as (22.64±2.36)% and (49.26±1.62)%, respectively. The results show that apatinib suppressed cell cycle progression at G(2)/M phase and induced cell apoptosis in both KYSE-150 and ECA-109 cells (P<0.05 for all). In the presence of 20 µmol/L and 40 µmol/L of apatinib in KYSE-150 cells, the relative levels of VEGF mRNA were (42.57±10.43)% and (25.69±1.24)%, and those of VEGF-2 mRNA were (36.09±10.82)% and (13.99±6.54)%, which were all significantly decreased compared to control group (100.00±0.00, P<0.05 for all). For ECA-109 cells, the relative expression of VEGF and VEGFR2 showed similar tendency (P<0.05 for all). Moreover, after treatment with 20 µmol/L and 40 µmol/L of apatinib in KYSE-150 cells, the VEGF concentrations were (766.48±114.27) pg/ml and (497.40±102.18)pg/ml, which were significantly decreased compared to control group [(967.41±57.75) pg/ml, P<0.05)]. The results in ECA-109 were consistent (P<0.05). Furthermore, after treatment with 40 µmol/L of apatinib in KYSE-150 and ECA-109, the relative expression of p-MEK and p-ERK were 0.49±0.05 and 0.28±0.03 as well as 0.63±0.03 and 1.22±0.15, which were significantly lower than control group (1.23±0.19 and 0.66±0.07 as well as 1.03±0.20 and 1.76±0.20; P<0.05). The relative expression of STAT3, p-STAT3 in control group and experimental group were 0.96±0.15 and 0.85±0.16 as well as 0.62±0.09 and 0.36±0.13, respectively. The results showed that the protein levels of STAT3 and p-STAT3 were significantly lower than the control group (P<0.05 for all). The inhibition rates of apatinib in xenograft nude mice were 29.25% and 19.96% for 250 mg and 500 mg treatment groups. The concentration of VEGF were (25.11±4.12) pg/ml, (16.40±2.81) pg/ml and (15.04±4.88)pg/ml for control, 250 mg and 500 mg treatment groups, respectively. Conclusions: Apatinib can inhibit cell proliferation, induce apoptosis and suppress migration of esophageal cancer cells in vitro and in vivo. This effect was mainly mediated via the alterations of Ras/Raf/MEK/ERK pathway and JAK2/STAT3 pathway.

Inflammation in lung after acute myocardial infarction is induced by dendritic cell-mediated immune response.

The present study was performed to describe the changes of lung tissues in mice with acute myocardial infarction (AMI) and also explain the cell mechanism involved in inflammation in lung. AMI was established by left coronary ligation in mice. Then mice were divided into three groups: control group, MW1 group (sampling after surgery for one week) and MW2 group (sampling after surgery for two weeks). Afterwards, measurement of lung weight and lung histology, cell sorting in bronchoalveolar lavage (BAL) fluid and detection of several adhesive molecules, inflammatory molecules as well as enzyme associated with inflammation were performed. Moreover, dendritic cells (DCs) were isolated from bone marrow of C57B/L6 mice. After incubating with necrotic myocardium, the expression of antigen presenting molecules, co-stimulatory molecules and inflammatory molecules were detected by flow cytometry or immunohistochemistry in DCs. We also detected T-cell proliferation after incubating with necrotic myocardium-treated DCs. AMI induced pathological changes of lung tissue and increased inflammatory cell amount in BAL fluid. AMI also increased the expression of several inflammatory factors, adhesive molecules and enzymes associated with inflammation. CD11c and TLR9, which are DC surface markers, showed a significantly increased expression in mice with AMI. Additionally, necrotic myocardium significantly increased the expression of co-stimulatory factors including CD83 and CD80, inflammatory cytokines including TNF-α, IFN-γ and NF-κB in DCs. Furthermore, DCs treated with necrotic myocardium also significantly promoted T-cell proliferation. AMI induced inflammation in lung and these pathological changes were mediated by DC-associated immune response.

Snail-induced epithelial-mesenchymal transition in gastric carcinoma cells and generation of cancer stem cell characteristics.

Biological changes in Snail-overexpressed SGC7901 cells were studied by establishing a pEGFP-C1-Snail carrier. The significance of Snail in epithelial-mesenchymal transition (EMT) as well as the invasion and metastatic capacity of gastric cancer cells was also discussed; moreover, we attempted to verify the probable cancer stem cell characteristics of Snail-overexpressed cells. A pEGFP-C1-Snail eukaryotic expression plasmid was constructed and pEGFP-C1(-) and pEGFP-C1-Snail plasmids were extracted and transfected into SGC7901 cells using Lipofectamine 2000. Stably expressed SGC7901-N [control group containing pEGFP-C1(-)] and SGC7901-S (test group containing pEGFP-C1-Snail) cells were screened using a G418 resistance medium. Snail, E-cadherin, b-catenin, vimentin, and fibronectin gene and protein expressions were detected by real-time quantitative PCR, western blot, and immunofluorescence. Cell invasion and metastasis were tested by scratch test, invasion assay, and an adhesion experiment. The positive rate of aldehyde dehydrogenase-1 (ALDH-1) expression was analyzed by flow cytometry. The results indicated the occurrence of EMT, accompanied by morphological changes in the cells and a weakening of the cell adhesion capacity. We also observed a decrease in the expression of epithelial markers E-cadherin and b-catenin and an increase in mesenchymal (Snail and vimentin) marker expression. Moreover, the cells showed increased invasiveness and metastatic capacity, and decreased proliferative ability. Moreover, the Snail-treated SGC7901 cells moved towards the scratch and produced fewer clones compared to the control cells. Owing to its capacity for self-renewal, SGC7901-S cells produced new clones and expressed ALDH-1. Therefore, we concluded that Snail overexpression induced EMT and endowed cells with tumor stem cell characteristics.

Proline-rich tyrosine kinase 2 and its phosphorylated form pY881 are novel prognostic markers for non-small-cell lung cancer progression and patients' overall survival.

BACKGROUND: Our previous study revealed that proline-rich tyrosine kinase 2 (Pyk2) is implicated in both anchorage-independent growth and anoikis resistance in lung cancer cells. This study aims to explore the expression and clinical significance of Pyk2 and its phosphorylated forms in non-small-cell lung cancer (NSCLC). METHODS: The mRNA and protein levels of Pyk2 or cancer stem cell markers (ALDH1a1, ABCG2 and Bmi-1) were either examined by reverse transcription-PCR or western blotting. An immunohistochemistry (IHC) assay was conducted to analyse the expression of Pyk2 and its phosphorylated forms in 128 NSCLC cases. RESULTS: The levels of Pyk2 mRNA, total protein, and its phosphorylated form pY881 were higher in lung cancer lesions than in the paired noncancerous tissues. The IHC analysis showed the levels of the Pyk2 and Pyk2[pY881] proteins were highly expressed in 70 (54.7%) and 77 (60.2%) cases, respectively. Both Pyk2 and Pyk2[pY881] were independent prognostic factors for NSCLC patients. The gain and loss study of Pyk2 function revealed that Pyk2 could upregulate the expression of ALDH1a1, ABCG2 and Bmi-1 and enhance the ability of colony formation in soft agar assay in A549 and H460 cells. CONCLUSION: Both Pyk2 and phosphorylated Pyk2[pY881] are potential prognostic factors and therapeutic targets for NSCLC.

Efficacy and safety evaluation of intensive statin therapy in older patients with coronary heart disease: a systematic review and meta-analysis.

PURPOSE: To reveal and evaluate the efficacy and safety of intensive statin therapy in older patients (age ≥ 65 years) with coronary heart disease (CHD). METHODS: Electronic databases were searched for randomized controlled trials (RCTs) that involved intensive statin therapy use in older patients with CHD. Data was extracted and used to calculate risk ratios (RR) by software Revman 5.1. RESULTS: Five RCTs and 11,132 patients were included in. Compared with non-intensive statin therapy, intensive statin therapy had significant effect on reducing low density lipoprotein cholesterol (LDL-C) levels (55.4 %) and total cholesterol (TC) and triglyceride (Tg). Although the results showed that intensive statin therapy had no superior effect on reduction of mortality (both all-cause mortality [RR = 0.97, p = 0.65] and cardiac death [RR = 0.95, p = 0.57]) and cardiac arrest (RR = 1.09, p = 0.81), it possessed significant effects on prevention of nonfatal myocardial infarction (MI) (RR = 0.78, p = 0.008), stroke (RR = 0.72, p = 0.02) and coronary revascularization (RR = 0.69, p = 0.007). In terms of side effects, intensive statin therapy was associated with small absolute increase in incidence of drug discontinuation, due to adverse events (3.9 %) and liver enzymes abnormalities (1.7 %). And the occurrence rates of myopathy, rhabdomyolysis and creatine kinase (CK) elevation were very low. CONCLUSIONS: This results show that intensive statin therapy has excellent effects on reduction of serum lipid level including LDL-C, TC, Tg, and also on prevention of nonfatal MI, stroke and coronary revascularization with small absolute increased risk of side effects. Our analysis supports the use of intensive statin therapy in patients ≥ 65 years old with CHD.

A gene mutated in X-linked myotubular myopathy defines a new putative tyrosine phosphatase family conserved in yeast.

X-linked recessive myotubular myopathy (MTM1) is characterized by severe hypotonia and generalized muscle weakness, with impaired maturation of muscle fibres. We have restricted the candidate region to 280 kb and characterized two candidate genes using positional cloning strategies. The presence of frameshift or missense mutations (of which two are new mutations) in seven patients proved that one of these genes is indeed implicated in MTM1. The protein encoded by the MTM1 gene is highly conserved in yeast, which is surprising for a muscle specific disease. The protein contains the consensus sequence for the active site of tyrosine phosphatases, a wide class of proteins involved in signal transduction. At least three other genes, one located within 100 kb distal from the MTM1 gene, encode proteins with very high sequence similarities and define, together with the MTM1 gene, a new family of putative tyrosine phosphatases in man.

[Variables associated with hematological remission and survival in patients with acute myeloid leukemia after induction failure and relapse].

Objective: This study aimed to explore variables associated with remission rate and survival in patients with acute myeloid leukemia (AML) after induction failure and relapse. Methods: Data of 373 consecutive patients with AML were analyzed after induction failure and relapse. Binary logistics and the Cox model regression were used to identify variables associated with remission rate and outcomes. Results: In patients with AML after induction failure and relapse, the total CR+CRi rates were 50.6% and 40.3%, respectively; among those who achieved CR/CRi, the 3-year RFS rates were 34.4% and 30.4%, respectively, and the 3-year overall survival rates were 40.1% and 31.6%, respectively. In the multivariate analyses, using CLAG or FLAG regimen as a re-induction chemotherapy regimen, age <39 years and SWOG low-risk were significantly associated with higher remission rates in patients with induction failure. Male, secondary AML, SWOG high-risk, the interval from the first remission to relapse within 12 months, and bone marrow blasts ≥20% at the time of relapse were significantly associated with lower remission rates in relapsed patients. Transplantation was significantly associated with prolonged relapse-free survival and overall survival in patients achieving hematologic remission; the SWOG low-risk group was significantly associated with longer overall survival in those with induction failure; and achieving CR (not CRi) or having female gender was associated with longer RFS or overall survival in relapsed patients. Conclusion: Reinduction chemotherapy regimen, age, gender, SWOG risk, secondary AML, the interval from the first remission to relapse, and bone marrow blast percentage at the time of relapse were significantly associated with remission rates in the patients with AML after induction failure and relapse. Transplantation, SWOG low-risk, achieving CR, or female gender were associated with longer survivals in those achieving remission.

[The efficacy and safety of low-dose chemotherapy combined with tyrosine kinase inhibitors in the treatment of Philadelphia-chromosomal-positive acute lymphoblastic leukemia].

Objective: The study aims to explore the efficacy and safety of low-dose chemotherapy combined with tyrosine kinase inhibitor (TKI) as an induction therapy for Philadelphia-chromosomal-positive acute lymphoblastic leukemia (Ph(+) ALL) . Methods: The data of the consecutive newly diagnosed patients with Ph(+) ALL were reviewed. The efficacy and safety of low-dose chemotherapy and conventional-dose chemotherapy combined with TKI were compared. Results: A total of 217 patients with a median age of 38 (10-69) years old were included in this study. 78 patients were in the low-dose chemotherapy group, and 139 patients were in the conventional-dose chemotherapy group. There were no significant differences in the 4-week complete remission (CR) rate (98.7% vs 97.0%, P=0.766) and overall CR rate (100% vs 100%, P=1.000) between the two groups. Multivariate analyses showed that the chemotherapy intensity was not related to the disease-free survival rate and overall survival rate. However, the lower incidence of infection (P=0.017) , the shorter duration of neutropenia (P=0.001) and PLT<20 × 10(9)/L (P=0.057) , and the lower red blood cell transfusion volume (P=0.002) were more common in the low-dose chemotherapy group than in the conventional-dose chemotherapy group. Conclusions: The low-dose chemotherapy is superior to the conventional-dose chemotherapy combined with TKI as induction therapy in Ph(+) ALL with similar efficacy but is safer.

Venous thromboembolism risk in rheumatoid arthritis patients: a systematic review and updated meta-analysis.

OBJECTIVE: Rheumatoid arthritis (RA) patients are prone to develop thromboembolic complications due to the chronic inflammatory nature of RA. Only one systematic review and meta-analysis has attempted to evaluate venous thromboembolism risk in RA patients. However, this review has become outdated due to the recent publication of several high-quality retrospective cohort studies. The aim of the study was to evaluate the risks of deep vein thrombosis, pulmonary embolism, and overall venous thromboembolism event incidence in RA patients. MATERIALS AND METHODS: Five databases (Web of Science, EMBASE, CENTRAL, Scopus, and MEDLINE) were systematically searched according to PRISMA guidelines for eligible studies. With the available literature, we conducted a random-effect meta-analysis to evaluate odds ratios of deep vein thrombosis, pulmonary embolism, and venous thromboembolism incidence in RA patients and healthy controls. RESULTS: We found 12 eligible studies detailing 272,884 RA patients and 2,280,454 age and sex-matched healthy controls. Meta-analysis revealed elevated risks for deep vein thrombosis (Odd's ratio: 2.25), pulmonary embolism (2.15), and overall venous thromboembolism incidence (2.23) in RA patients. CONCLUSIONS: This meta-analysis provides evidence concerning the elevated risks of deep vein thrombosis, pulmonary embolism, and venous thromboembolism in RA patients. The findings herein may aid in developing clinical awareness and assisting best practice guideline development for RA patients with thromboembolic complications.

MiR-449b-5p inhibits human glioblastoma cell proliferation by inactivating WNT2B/Wnt/ß-catenin signaling pathway.

OBJECTIVE: As the most common primary brain cancer in adults, glioblastoma shows an extremely poor prognosis. Glioblastoma-associated deaths account for approximately 3%-4% of all malignancy-associated deaths. Numerous microRNAs (miRNAs) play important roles in the occurrence and progression of solid tumors. Herein, identifying functional miRNAs and the central molecular mechanisms would provide novel proofs for the development of targeted cancer therapies. In this study, we described the role of miR-449b-5p in restraining ontogenesis and progression of glioblastoma. PATIENTS AND METHODS: Human glioblastoma tissues were provided by our hospital. Human U251 glioblastoma cells were infected with lentivirus induced miR-449b-5p mimics or miR-449b-5p siRNA. Real-time qPCR was carried out to determine miRNA expression. Tumor spheres formation, MTT assay, and BrdU cell proliferation assay were used to evaluate the growth ability of U251 cells. Western blot assay was performed to measure protein expression. ChIP was used to detect the capacity of ß-catenin to recruit its downstream genes. Dual-Luciferase assay was conducted to detect the ability of miR-449b-5p to regulate the 3'UTR (untranslated regions) of WNT2B. TOP/FOP ratio was used to evaluate the activity of Wnt/ß-catenin signaling pathway. RESULTS: Down-regulation of miR-449b-5p expression was found in both human glioblastoma tissues and cell lines, which was negatively associated with the clinical stages. Up-regulation of miR-449b-5p inhibited tumor spheres formation, cell viability and proliferation ability of glioblastoma cells. The expression levels of WNT2B and nuclear ß-catenin were negatively associated with miR-449b-5p levels in glioblastoma cells. MiR-449b-5p inhibited Wnt/ß-catenin signaling by targeting WNT2B. CONCLUSIONS: MiR-449b-5p acts as a tumor suppressor and retards the oncogenesis of glioblastoma, which is achieved via inactivation of Wnt/ß-catenin signaling by directly targeting WNT2B.

[Effects of artesunate combined with bortezomib on apoptosis and autophagy of acute myeloid leukemia cells in vitro and its mechanism].

Objective: To investigate the effects of artesunate combined with bortezomib on the proliferation, apoptosis and autophagy of human acute myeloid leukemia cell lines MV4-11, and its mechanisms. Methods: MTT method was used to determine the anti-proliferation effect of different concentrations of artesunate, bortezomib and their combination on MV4-11 cells. The cell apoptosis were analyzed by flow cytometry. The expression of cleaved-Caspase-3, Bcl-2 family protein (Bcl-2, Mcl-1, Bim, Bax) and autophagy-related protein LC3B were assayed by Western blot. Results: Artesunate displayed a proliferation inhibition effect on MV4-11 with dose- and time-dependent manner, the IC(50) of artesunate on MV4-11 after 48 hours was 1.44 µg/ml. Bortezomib displayed a proliferation inhibition effect on MV4-11 with dose-dependent manner, the IC(50) of bortezomib on MV4-11 after 48 hours was 8.97 nmol/L. The combination of artesunate (0.75, 1.0 µg/ml) and Bortezomib (6, 8 nmol/L) showed higher inhibition on MV4-11 than artesunate or bortezomib alone in the same concentration gradient after 48 hours (P<0.05) . The cooperation index of the two drugs were all less than 1. The 48 h apoptotic rate of artesunate (1.5 µg/ml) on MV4-11 was (15.27±2.18) %, (19.85±3.23) % of bortezomib (8 nmol/L) , (81.67±5.96) % of combination of the two drugs, significantly higher than the single group (P<0.05) . When combination of the two drugs on MV4-11 after 24 hours, the levels of pro-apoptotic protein Bim and the cleaved activation of Caspase-3 and autophagy-related protein LC3B were up-regulated and the anti-apoptotic protein Bcl-2 expressions was down-regulated. Conclusion: Combination of artesunate with bortezomib shows a significant synergistic effects on proliferation, apoptosis and autophagy of MV4-11 cell lines, which may be associated with Bcl-2 family proteins expression.

Subthreshold depression is associated with impaired resting-state functional connectivity of the cognitive control network.

Subthreshold depression (StD) is a prevalent condition associated with social morbidity and increased service utilization, as well as a high risk of developing into a major depressive disorder (MDD). The lack of well-defined diagnostic criteria for StD has limited research on this disorder, with very few brain-imaging studies examining the neurobiology of StD. Yet, identifying the neural pathology of StD has the potential to elucidate risk factors and prognostic markers for major depression and is crucial for developing tailored treatments for patients at mild stages of depression. We investigated resting-state functional connectivity (rs-FC) of the cognitive control network (CCN), known to be dysregulated in MDD, using the bilateral dorsolateral prefrontal cortex (DLPFC) as a seed, focusing on two cohorts of StD subjects (young and middle aged) as well as matched controls. Irrespective of age, we found a significant rs-FC decrease in the CCN of the StD subjects, compared with matched controls, particularly between the DLPFC and the brain regions associated with the representation of self and other mental states (temporo-parietal junction (TPJ) and precuneus), as well as salience detection and orienting (insula). The functional connectivity between the DLPFC and the left TPJ was also associated with depressive symptom scores measured by the Center for Epidemiologic Studies Depression Scale. This finding may shed light on the neural pathology of StD, leading to better understanding of mild stages of depression, its diagnosis and the development of new treatments.

Genomic organization of the MTM1 gene implicated in X-linked myotubular myopathy.

X-linked recessive myotubular myopathy (XLMTM) is a very severe congenital muscular disease characterised by an impaired maturation of muscle fibres, and caused by defects in the MTM1 gene. This gene defines a new family of putative tyrosine phosphatases conserved through evolution. We have determined intronic flanking sequences for all the 15 exons to facilitate the detection of mutations in patients and genetic counselling. We characterised a new polymorphic marker in the immediate vicinity of the gene, which might prove useful for linkage analysis. Sequencing of the TATA-less predicted promoter provides the basis for transcriptional regulatory studies.

Cytotoxicity and cell-cycle effects of paclitaxel when used as a single agent and in combination with ionizing radiation.

PURPOSE: This study aimed to determine the extent of paclitaxel-induced cytotoxicity and cell-cycle perturbations when used alone and in combination with radiation in human glioma cells. METHODS AND MATERIALS: The effect of paclitaxel alone on three human glioma cells lines--SF-126, U-87 MG, and U-251 MG--was assessed after 24, 48, 72, or 96 h treatment. For experiments in combination with radiation, cells were exposed to either a long (48-h) or short (8-h) duration of paclitaxel treatment prior to irradiation. Cell survival was determined by clonogenic assay. Cell cycle perturbations were assessed by using flow cytometry to measure the proportion of cells in G1, S, and G2/M phases. RESULTS: When cells were treated with paclitaxel alone for > or = 24 h, cytotoxicity increased up to a threshold dose, after which it plateaued. When treatment duration was < or = 24 h, cytotoxicity was appreciably greater in U-251 MG cells than in SF-126 and U-87 MG cells. After 24 h of paclitaxel treatment, cells in plateau phase growth had increased survival compared to cells in log phase growth. In contrast, after 8 h paclitaxel treatment, mitotic cells had reduced survival compared to cells from an asynchronous population. Cell-cycle perturbations were consistent with the presence of a mitotic block after paclitaxel treatment, although changes in other cell-cycle phase fractions varied among cell lines. For experiments in combination with radiation, cytotoxicity was increased when cells were irradiated after 48 h of paclitaxel treatment but not after 8 h of treatment. CONCLUSION: The duration of paclitaxel treatment and the location of cells in the cell cycle modify the degree of radiation cytotoxicity. The mechanisms of paclitaxel cytotoxicity are likely to be multifactorial because varying effects are seen in different cell lines. Furthermore, it is clear that simply increasing the number of cells in G2/M is insufficient in itself to increase the response of cells to radiation.

Radiopotentiation of human brain tumor cells by the spermine analog N1,N14-bis(ethyl)homospermine.

PURPOSE: To determine whether the cytotoxicity produced by radiation can be increased by the spermine analog N1,N14-bis(ethyl)homospermine (BE-4-4-4). METHODS AND MATERIALS: Two human tumor cell lines, SF-126 and U-251 MG, were either treated with 0.1 or 0.4 microM BE-4-4-4 for 3 or 4 days, or with 0.2 microM BE-4-4-4 for 4 days. At the end of BE-4-4-4 treatment, cells were irradiated and assayed immediately. Polyamine levels, cell survival, and cell number were determined. RESULTS: In SF-126 cells, treatment with 0.2 microM BE-4-4-4 for 4 days killed about 50% of the cells and also increased the cytotoxicity of radiation. The dose enhancement ratio was approximately 1.3:1.5, which is similar to that reported for alpha-difluoromethylornithine. Polyamine levels were partially depleted, and growth was inhibited to about 60% of control levels. Pretreatment of cells with either 0.1 or 0.4 microM BE-4-4-4 for 3 or 4 days produced less of an increase in radiation-induced cytotoxicity, even though these exposures killed 30-40% or 60-90% of the cells, respectively. Similar treatment with 0.1-0.4 microM BE-4-4-4 in U-251 MG cells had minimal effects on cytotoxicity and growth inhibition, while treatment with 1.0 microM and 2.0 microM BE-4-4-4 for 4 days produced more than a 50% depletion in polyamine levels and partial inhibition in growth, but failed to demonstrate radiopotentiation. CONCLUSION: The cytotoxic polyamine analog BE-4-4-4 can increase the cytotoxicity caused by radiation in at least one cell line. The amount of potentiation depends on the concentration of the analog, with the most occurring at the intermediate concentration. Because we did not observe potentiation in both cell lines, and because of the dose dependence seen in SF-126 cells, the clinical efficacy produced by combined BE-4-4-4 and radiation protocols may be limited.

Radiopotentiation of human brain tumor cells by sodium phenylacetate.

Phenylacetate (PA) inhibits the growth of tumor cells in vitro and in vivo and shows promise as a relatively nontoxic agent for cancer treatment. A recent report shows that prolonged exposure of cells to low concentrations of PA can enhance the radiation response of brain tumor cells in vitro, opening up the possibility of using this drug to improve the radiation therapy of brain tumor patients. We investigated the cytotoxicity produced by sodium phenylacetate (NaPA) alone and in combination with X-rays in SF-767 human glioblastoma cells and in two medulloblastoma cell lines, Masden and Daoy. Exposure of all three cell lines to relatively low concentrations of NaPA for up to 5 days did not enhance the subsequent cell killing produced by X-irradiation. However, enhanced cell killing was achieved by exposing either oxic or hypoxic cells to relatively high drug concentrations ( > 50-70 mM) for 1 h immediately before X-irradiation. Because central nervous system toxicity can occur in humans at serum concentrations of approximately 6 mM PA, translation of these results into clinical trials will likely require local drug-delivery strategies to achieve drug concentrations that can enhance the radiation response. The safety of such an approach with this drug has not been demonstrated.

Non-specific X-linked mental retardation: linkage analysis in MRX2 and MRX4 families revisited.

We have previously reported linkage analysis in 3 families with non-specific X-linked mental retardation (XLMR). This used RFLPs and was limited by the relatively low informativeness and density of markers available. We have performed a new linkage analysis using microsatellites (including new Genethon markers) in the two most informative families. In the MRX2 family, a lod score of 2.61 at theta = 0.05 had previously been obtained with DXS85 in Xp22.2. We now report a tighter linkage with AFM 135xe7 (DXS989, z = 4.62 at theta = 0.00) and established the order DXS85-DXS207-DXS999 (AFM234 y12)-MRX2, DXS365, DXS1052 (AFM 163yh2), DXS989-DXS1065 (AFM224zf2), DMD 3'. The localization of MRX2 in Xp22.2-p22.1 is thus clearly different from the more distal MRX gene defined by patients with contiguous gene syndromes. In the MRX4 family, a maximum lod score of 2.53 at theta = 0.00 had been obtained with DXS159 in Xq13. Our present study did not show recombination from ALAS2 in Xp11.21 to DXS441 in Xq13.3 (z = 3.38 at theta = 0.00 for the latter marker) and the closest flanking markers are DXS255 in Xp11.22 and DXYS1 in Xq21.3. Reduced recombination around the centromere prevents precise mapping. The localisation of MRX4 overlaps with that of several other MRX families.