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1.
Curr Med Sci ; 39(3): 379-384, 2019 Jun.
Article in English | MEDLINE | ID: mdl-31209806

ABSTRACT

Small cell lung cancer (SCLC) is recognized as one of the most aggressive and fatal malignant tumors. No significant improvement has been made to prolong the survival of SCLC patients. This study aimed to examine the mutation status of K-Ras (KRAS) and phosphatase and tensin homolog (PTEN) in SCLC patients in order to identify potential therapeutic targets for SCLC. Nineteen primary SCLC tumor specimens were enrolled in the study. Direct sequencing was performed to detect the mutations of KRAS exon 3 and PTEN exon 7 in the specimens. Kaplan- Meier and Cox regression analysis was performed to determine the overall survival (OS) of these SCLC patients. KRAS exon 3 mutation was found in 4 (21%) SCLC patients, and PTEN exon 7 mutation in only 1 (5%) SCLC patient. Kaplan Meier analysis showed that clinical stage and brain metastasis were significantly associated with OS (both P<0.05), but neither KRAS exon 3 mutation nor PTEN exon 7 mutation was significantly associated with OS (P>0.05). Cox proportional hazards regression model indicated that extensive stage of disease was the only independent negative prognostic factor for OS in SCLC patients. In conclusion, KRAS exon 3 and PTEN exon 7 mutations had no significant impact on OS of SCLC patients. Further study is still necessary to validate the molecular profiles of SCLC.


Subject(s)
Brain Neoplasms/genetics , Lung Neoplasms/genetics , Mutation , PTEN Phosphohydrolase/genetics , Proto-Oncogene Proteins p21(ras)/genetics , Small Cell Lung Carcinoma/genetics , Aged , Brain Neoplasms/diagnosis , Brain Neoplasms/mortality , Brain Neoplasms/secondary , DNA Mutational Analysis , Exons , Female , Gene Expression , Humans , Lung/metabolism , Lung/pathology , Lung Neoplasms/diagnosis , Lung Neoplasms/mortality , Lung Neoplasms/pathology , Male , Middle Aged , Neoplasm Staging , Prognosis , Proportional Hazards Models , Prospective Studies , Small Cell Lung Carcinoma/diagnosis , Small Cell Lung Carcinoma/mortality , Small Cell Lung Carcinoma/secondary
2.
Onco Targets Ther ; 11: 2217-2226, 2018.
Article in English | MEDLINE | ID: mdl-29720878

ABSTRACT

BACKGROUND: Small cell lung cancer (SCLC) is an aggressive and deadly neuroendocrine tumor derived from bronchial epithelial cells. Although it results in a 95% mortality rate, the development of targeted therapies for SCLCs has lagged behind. The aim of this study is to better research mutation characteristics of SCLC and identify potential biomarkers for target therapy. METHODS: We utilized high-resolution melting analysis to identify the mutations in epidermal growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene (KRAS), v-raf murine sarcoma viral oncogene homolog B1 (BRAF), phosphatase and tensin homolog (PTEN), and phosphatidylinositol-3-kinase catalytic (PIK3CA) from the blood. A cohort of 99 SCLC patients including 44 limited-stage disease patients and 55 extensive-stage disease patients were prospectively collected. RESULTS: EGFR 18 (G719X) mutation was found in 5 patients, EGFR 19 (del) mutation in 2, EGFR 20 (T790M) in 3, EGFR 21 (L858R) in 2, KRAS 2 (G13D) in 5, BRAF 15 (V600E) in 1, PIK3CA 9 (E542K) in 1, and no mutations in PTEN 5 (R130G), PTEN 6 (R173C), PTEN 8 (T319fs*1), and PIK3CA 20 (H1047R) were identified. Among these patients, two harbored EGFR double mutation, one patient with EGFR double mutation and KRAS 2 (G13D) mutation. CONCLUSION: The mutation form of EGFR may differ from lung adenocarcinoma, and mutations of KRAS, BRAF, and PIK3CA were rare in SCLC. These results aided us in comprehensively analyzing genetic features and laid the foundation for exploring the possibility of target therapy.

3.
Adv Clin Exp Med ; 26(7): 1091-1094, 2017 Oct.
Article in English | MEDLINE | ID: mdl-29211356

ABSTRACT

BACKGROUND: Small cell lung cancer (SCLC) includes pure SCLC and SCLC combined with other pathologies (C-SCLC). C-SCLC accounts for about 28% of all SCLCs subjected to surgical resection, but only about 1%-3% of C-SCLCs are detected by biopsy. Since less than 5% of SCLC patients are eligible for surgery, it is necessary to develop alternative methods for the detection of C-SCLC. OBJECTIVES: We determined whether serum carcinoembryonic antigen (CEA) levels, which are usually elevated in lung adenocarcinomas, could be used to differentiate between pure SCLC and SCLC combined with adenocarcinoma. MATERIAL AND METHODS: We reviewed the records of 41 SCLC patients (35 with pure SCLC, 6 with C-SCLC) who underwent surgical resection between 2000 and 2014 in Zhejiang Cancer Hospital. Their preoperative serum CEA levels were noted, and the relationship between CEA level and the type of SCLC was analyzed. RESULTS: Serum CEA levels >6ng/mL were found more frequently in C-SCLC patients than in pure SCLC patients (p = 0.031). No such difference was observed when a CEA cut-off of 5ng/mL was used (p = 0.316). CONCLUSIONS: A preoperative serum CEA of >6ng/mL may be used as a reference in the diagnosis of SCLC combined with adenocarcinoma.


Subject(s)
Adenocarcinoma/diagnosis , Carcinoembryonic Antigen/blood , Lung Neoplasms/diagnosis , Small Cell Lung Carcinoma/diagnosis , Adenocarcinoma/blood , Adenocarcinoma/surgery , Adenocarcinoma of Lung , Adult , Aged , Female , Humans , Lung Neoplasms/blood , Lung Neoplasms/surgery , Male , Middle Aged , Small Cell Lung Carcinoma/blood , Small Cell Lung Carcinoma/surgery
4.
Adv Clin Exp Med ; 25(3): 397-402, 2016.
Article in English | MEDLINE | ID: mdl-27629725

ABSTRACT

BACKGROUND: Despite advances in chemotherapy and radiotherapy in recent decades, the prognosis for small cell lung cancer (SCLC) patients is still poor. Targeted therapies in SCLC must be applied systemically to target not only the primary tumor but also metastases. The phosphatidylinositol 3-kinase (PI3K)/AKT pathways play a key regulatory function in the survival, proliferation, energy metabolism and cellular architecture advantages of malignant cells. The phosphatidylinositol 3-kinase catalytic α (PIK3CA) gene, which encodes the p110α catalytic subunit, plays a key role in the activation of AKT downstream signaling and mammary tumor progression. More than 75% of PIK3CA mutations are clustered in the helical (exon 9) and catalytic domains (exon 20). There have been very few studies reporting the PIK3CA mutations status of patients with SCLC who have undergone surgical treatment in mainland China. OBJECTIVES: The aim of the study was to investigate the PIK3CA mutation in SCLC. MATERIAL AND METHODS: Reverse transcription polymerase chain reaction (RT-PCR) and direct sequencing technology was used to detect the PIK3CA mutation in 14 cases of retrospectively collected SCLC patients who underwent surgical treatment at Zhejiang Cancer Hospital, Hangzhou, PRC, between 2002 and 2010. RESULTS: The research revealed no mutations in exons 9 and 20 of the PIK3CA gene. A nucleotide alteration of A1634C (E545A) of exon 9 turned out to be a pseudogene-positive, because the mutation disappeared when near-duplicate detection was employed. CONCLUSIONS: The incidence of PIK3CA mutation is low in SCLC patients, and the pseudogene-positive alteration of A1634C is prone to occur in exon 9 of PIK3CA mutations in human cancers.


Subject(s)
Lung Neoplasms/genetics , Mutation, Missense , Phosphatidylinositol 3-Kinases/genetics , Small Cell Lung Carcinoma/genetics , Adult , Aged , Base Sequence , Class I Phosphatidylinositol 3-Kinases , DNA Mutational Analysis , Exons/genetics , Female , Gene Frequency , Humans , Lung Neoplasms/surgery , Male , Middle Aged , Pseudogenes/genetics , Small Cell Lung Carcinoma/surgery
5.
Oncotarget ; 7(21): 31299-310, 2016 May 24.
Article in English | MEDLINE | ID: mdl-27121317

ABSTRACT

Blood-tumor barrier (BTB) reduce the permeability for drugs into tumor tissues. We found that histamine might serve as an essential regulator of BTB function. Further, we aim to determine the role of H2 receptor expression in BTB permeability, and elucidate the underlying mechanisms thereof. Transmission electron microscopy showed that histamine disrupted the integrity of tight junctions (TJ) and increased the number of pinosomes in the cytoplasm. Horseradish peroxidase (HRP) and trans-endothelial resistance detection (TEER) assays revealed that histamine could open BTB and this action was inhibited by cimetidine. Western blot and immunofluorescence assays showed that histamine decreased the expression of tight junction proteins zonula occluden-1(ZO-1), occludin, and claudin-5. Further, quantitative RT-PCR assay showed that the expression of H2 receptor could represent and predicted histamine-induced BTB permeability. In conclusion, histamine opened BTB by down-regulating the TJ-associated proteins. The levels of H2 receptor expression was correlated with the histamine-induced BTB permeability.


Subject(s)
Blood-Brain Barrier/drug effects , Histamine/pharmacology , Tight Junctions/drug effects , Animals , Blood-Brain Barrier/metabolism , Blood-Brain Barrier/physiopathology , Blotting, Western , Brain Neoplasms/blood supply , Brain Neoplasms/metabolism , Brain Neoplasms/pathology , Cell Line, Tumor , Cells, Cultured , Coculture Techniques , Endothelial Cells/cytology , Endothelial Cells/metabolism , Glioma/blood supply , Glioma/metabolism , Glioma/pathology , Microscopy, Electron, Transmission , Permeability/drug effects , Rats, Sprague-Dawley , Receptors, Histamine H2/metabolism , Tight Junctions/metabolism , Tight Junctions/ultrastructure , Zonula Occludens-1 Protein/metabolism
6.
Onco Targets Ther ; 9: 171-81, 2016.
Article in English | MEDLINE | ID: mdl-26793001

ABSTRACT

FGFR1 amplification is recognized as a novel therapy target for non-small-cell lung cancer (NSCLC), especially in squamous cell carcinoma (SCC). However, the association between FGFR1 amplification and the clinicopathological characteristics of NSCLC remains controversial. We performed a meta-analysis of 17 eligible studies to examine the correlation between FGFR1 gene amplification and clinicopathological characteristics. FGFR1 amplification was closely related to these clinicopathological features, including sex (odds ratio [OR] 2.05, 95% confidence interval [CI] 1.50-2.80), smoking (OR 3.31, 95% CI 2.02-5.44), and histology (OR 3.60, 95% CI 2.82-4.59). FGFR1 amplification was associated with shorter overall survival, and no significant heterogeneity existed between studies (I (2)=3.8%). We should note that publication bias may partly account for these results, but our findings remained significant after the trim-and-fill method (hazard ratio 1.22, 95% CI 1.06-1.40). However, no significant correlation was found with poor disease-free survival (hazard ratio 1.43, 95% CI 0.96-2.12). In conclusion, this study showed that FGFR1 amplification was significantly associated with sex, smoking, and histology. FGFR1 amplification could be a marker of poor prognosis in NSCLC patients, especially in SCC patients.

7.
Adv Clin Exp Med ; 23(2): 191-5, 2014.
Article in English | MEDLINE | ID: mdl-24913109

ABSTRACT

BACKGROUND: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) such as erlotinib and gefitinib are targeted drugs for the kinase domain of EGFR. They are widely used for the treatment of non-small cell lung cancer (NSCLC). The EGFR exon 19 deletion mutation and the L858R mutation in exon 21 comprise approximately 90% of the somatic mutations in NSCLC patients that respond to EGFR TKI. Several recent studies have also reported that small cell lung cancer (SCLC) patients with EGFR mutations responded to gefitinib. Further study, however, has been limited due to the difficulty obtaining tumor specimens from SCLC patients. OBJECTIVES: The aim of this study was to explore the EGFR mutation status in SCLC patients by plasma analysis. MATERIAL AND METHODS: Plasma samples from SCLC patients were collected for mutant-enriched liquidchip (MEL) analysis to identify the EGFR mutations in exon 19 and 21. RESULTS: The exon 19 deletion mutation was detected in one out of 35 patients (a female non-smoker). No exon 21 mutations were found. CONCLUSIONS: A prevalence of EGFR mutations in SCLC is rare, and occurs most frequently in females and nonsmokers.


Subject(s)
Carcinoma, Small Cell/genetics , ErbB Receptors/genetics , Lung Neoplasms/genetics , Mutation , Polymerase Chain Reaction/methods , Carcinoma, Small Cell/blood , Female , Humans , Lung Neoplasms/blood , Male , Middle Aged
8.
Anat Rec (Hoboken) ; 296(4): 604-10, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23401468

ABSTRACT

Pancreatic cancer is one of the most lethal human malignancies with a very low 5-year survival rate, which highlights urgent needs for more effective therapeutic strategies. In this study, we examined the potential therapeutic effects of an adenovirus encoding human interferon gamma (Ad-IFNγ) on pancreatic carcinoma cells Capan-2 in vitro and in vivo. The results indicated that Ad-IFNγ could significantly inhibit tumor cell growth via inducing cell apoptosis. After infection, IFNγ expressed durably and stably in xenografts, predominantly in tumor tissue, while much less in blood and liver. Thus, adenovirus-mediated intratumoral injection of human IFNγ gene could be an effective gene therapeutic system for the treatment of pancreatic carcinoma.


Subject(s)
Adenoviridae/genetics , Apoptosis , Carcinoma/therapy , Genetic Therapy/methods , Genetic Vectors , Interferon-gamma/biosynthesis , Pancreatic Neoplasms/drug therapy , Animals , Carcinoma/genetics , Carcinoma/metabolism , Carcinoma/pathology , Cell Line, Tumor , Cell Proliferation , Female , Humans , Immunohistochemistry , Interferon-gamma/genetics , Mice , Mice, Nude , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/pathology , Time Factors , Transfection , Tumor Burden , Xenograft Model Antitumor Assays
9.
Oncol Lett ; 5(1): 3-11, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23255884

ABSTRACT

Lung cancer is the leading cause of cancer-related mortality. Small cell lung cancer (SCLC) accounted for 12.95% of all lung cancer histological types in 2002. Despite trends toward modest improvement in survival, the outcome remains extremely poor. Chemotherapy is the cornerstone of treatment in SCLC. More than two-thirds of patients who succumb to lung cancer in the United States are over 65 years old. Elderly patients tolerate chemotherapy poorly and need novel therapeutic agents. Targeted drugs have less toxicity than chemotherapy drugs, but no targeted agents have been approved for use in the treatment of SCLC patients to date. Certain new targeted agents, including gefitinib, bevacizumab and Bcl-2 inhibitors, offer a promise of improved outcomes, however negative results are more commonly reported than positive. This review focuses on targeted therapies in SCLC.

10.
Oncol Lett ; 4(1): 89-93, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22807968

ABSTRACT

Small cell lung cancer (SCLC) is a highly aggressive and lethal type of cancer in humans. SCLC is sensitive to chemotherapy and radiotherapy, but long-term survival is low and the majority of patients eventually develop progressive disease. With the success of imatinib mesylate in the treatment of gastrointestinal stromal tumors expressing c-kit, its use in SCLC serves as a novel molecular therapeutic approach. The activity of imatinib mesylate is correlated with the mutation of c-kit gene exons 9 and 11 in gastrointestinal stromal tumors. The incidence of epidermal growth factor receptor mutation in non-small cell lung cancer is higher in China than in the United States of America and European countries. There may be also differences in the incidence of c-kit mutation between China and European countries. At present, no study examining imatinib mesylate treatment for SCLC in China is available. To investigate the expression and mutation of c-kit and the correlation with prognosis of SCLC in China, immunohistochemistry was used to detect the expression of c-kit, and a pyrosequencing assay was used to detect mutations in c-kit exons 9 and 11 of 36 SCLC patients who received surgical treatment at the Zhejiang Cancer Hospital, Hangzhou, China, between 1998 and 2010. All 36 patients were followed up to analyze the correlation between prognosis and expression and mutation of c-kit. The incidence of c-kit-positive expression was 83.3%, including 25.0% weak staining, 22.2% moderate staining and 36.1% strong staining. The overall survival of patients with c-kit strong staining was shorter compared to patients with c-kit not strong staining. No mutation in c-kit exons 9 and 11 was detected. In conclusion, the findings showed that the expression of c-kit is high, and strong staining is a prognostic factor for worse survival.

11.
Oncol Lett ; 3(6): 1288-1292, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22783435

ABSTRACT

The mutation status of epidermal growth factor receptor (EGFR) is correlated with the response of tumors to EGFR tyrosine kinase inhibitors in non-small cell lung cancer (NSCLC), suggesting its usefulness as a biomarker in NSCLC. The incidence of EGFR mutation in NSCLC is higher in China than in the United States and European countries. There have been some case reports concerning cases of gefitinib-responsive small cell lung cancer (SCLC) with EGFR mutations. However, few large studies concerning the mutation status of SCLC patients have been performed. We detected EGFR mutations in exons 19 and 21 of 40 SCLC patients, three of whom had combined SCLC, from the Zhejiang Cancer Hospital using xTAG technology. Only two patients with combined SCLC had an EGFR mutation in exon 19. To determine the EGFR mutation status and clinical features of combined SCLC, we retrospectively analyzed the clinical features of seven patients with combined SCLC who had undergone surgical treatment in Zhejiang Cancer Hospital between 2007 and 2010. EGFR mutations in exons 19 and 21 were detected using the pyrosequencing assay. Of the seven patients with combined SCLCs, 71.4% were male, 71.4% were heavy smokers, most were over 60 years old and 71.4% of the cases were combined adenocarcinoma. Chemotherapy treatment and tumor stage were correlated with survival time. Of the seven cases, one had a mutation in exon 19 of EGFR in both the conventional SCLC and SCLC combined adenocarcinoma components. Combined SCLC commonly occurs in patients who are heavy smokers, male and over 60 years old, and most of the combined type cases are adenocarcinoma. The treatment of combined SCLC may be applied to cases of conventional SCLC. EGFR mutations may therefore occur in combined SCLCs, especially in SCLC combined adenocarcinoma in China.

12.
Oncol Lett ; 3(2): 415-420, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22740923

ABSTRACT

Individual therapy based on various pathohistological types and biological characteristics may be the practical trend of advanced non-small cell lung cancer (NSCLC) treatment. To provide a molecular criterion for drug selection, we investigated the incidence of somatic mutation and mRNA expression levels of common genes relevant to treatment response in a population with locally advanced NSCLC. Mutant-enriched and branched DNA-liquidchip technology (bDNA-LCT) were used to detect the somatic mutations in the epidermal growth factor receptor (EGFR), KRAS, BRAF and phosphatidylinositol-3-kinase catalytic α (PIK3CA) genes, and mRNA levels of EGFR, ERCC1, class III ß-tubulin (TUBB3) and TYMS, separately, in paraffin tissue blocks from 30 patients with stage IIIA NSCLC. Our current findings revealed that 6, 4 and 2 out of 30 samples were found with mutations in exons 19, 21 and 20 of the EGFR gene, respectively. The mutation incidence of exons 19 and 21 had a positive correlation with EGFR mRNA expression. Mutations in exons 12 and 13 of the K-ras gene were found in 2 out of 30, and 1 out of 30 samples, separately. Three out of 30 samples were found with mutations in codon 542 of the PIK3CA gene. No mutations were found in the BRAF gene. The expression levels of ERCC1 and TUBB3 mRNAs were higher in patients with adenocarcinoma than those in patients with squamous cell carcinoma. The expression of TYMS mRNA in patients with adenocarcinoma was lower than that in patients with squamous cell carcinoma. In conclusion, mutations and mRNA expression of these commonly studied genes provides a basis for the selection of suitable molecular markers for individual treatment in a population with locally advanced NSCLC.

13.
Anat Rec (Hoboken) ; 294(6): 941-4, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21548109

ABSTRACT

Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) was used to screen serum samples to identify protein markers for early breast cancer relapse. We collected 67 serum samples from patients with breast cancer (24 preoperative; 23 postoperative without breast cancer relapse; 20 postoperative with breast cancer relapse). Eight protein peaks varied between the presurgical group and the postsurgical group without breast cancer relapse; 4 protein peaks were differentially expressed between the postsurgical patients without relapse and patients with relapse. The peak at 3964 m/z dropped after surgery and rebounded after relapse (P < 0.01). These results indicate that there are differences in serum protein expression among the three different groups of patients. SELDI-TOF MS could be used to screen blood samples for the early detection of relapse in primary breast cancer patients. Specifically, protein peak at 3964 m/z is a potential biomarker for the detection of early breast cancer relapse.


Subject(s)
Biomarkers, Tumor/blood , Breast Neoplasms/blood , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Adult , Aged , Biomarkers/blood , Blood Proteins/analysis , Breast Neoplasms/diagnosis , Female , Humans , Middle Aged
14.
Zhonghua Yi Xue Za Zhi ; 87(25): 1749-51, 2007 Jul 03.
Article in Chinese | MEDLINE | ID: mdl-17919379

ABSTRACT

OBJECTIVE: To compare the curative effects and expenses of pleural drainage by using central venous catheter and of simple aspiration by thoracentesis in treatment of spontaneous pneumothorax. METHODS: 46 patients with spontaneous pneumothorax were randomly divided into 2 equal groups: Group A, treated with pleural drainage by using central venous catheter, and Group B, treated with simple aspiration by thoracentesis. The curative rate and average residual volume after treatment were used to evaluate the curative effects. The average hospitalization days, duration of treatment, and expenses for medical materials were used to evaluate as the economic index. RESULTS: (1) The effective rates were 100% and 91.30% in Groups A and B respectively. (2) The average residual volume of pneumothorax at the time of discharge from hospital of Group A was 4.17%, significantly lower than that of Group B (18.62%, P < 0.05). (3) The average residual volume of pneumothorax 1 week after discharge of Group A was 0.53%, significantly lower than that of Group B (7.59%, P < 0.01). (4) The expense for medical materials of Group A was 264.79 Yuan RMB, a little bit more than that of Group B (233.62 Yuan RMB). (5) The hospitalization time of Group A was 5.32 days, significantly shorter than that of Group B (7.68 days, P < 0.05). The duration of treatment with antibiotics of Group A was 3.46 days, significantly shorter than that of Group B (5.59 days, P < 0.05). The time of oxygen inhalation of Group A was 86.4 hours, significantly shorter than that of Group B (133.1 hours, P < 0.01). CONCLUSION: With higher curative effect and lower expenses, pleural drainage by using central venous catheter is superior to simple aspiration in treatment of spontaneous pneumothorax, and can be the first choice.


Subject(s)
Catheterization, Central Venous/methods , Drainage/methods , Minimally Invasive Surgical Procedures/methods , Pneumothorax/therapy , Adult , Anti-Bacterial Agents/therapeutic use , Catheterization, Central Venous/economics , Catheters, Indwelling , Female , Humans , Male , Minimally Invasive Surgical Procedures/economics , Pleural Cavity/surgery , Pneumothorax/pathology , Punctures , Treatment Outcome
15.
J Colloid Interface Sci ; 316(1): 160-7, 2007 Dec 01.
Article in English | MEDLINE | ID: mdl-17719056

ABSTRACT

Nanocrystalline TiO(2) rods and hollow tubes with an engraved pattern on the surface have been prepared by a novel anionic template-assisted sol-gel synthesis via urea treatment and under hydrothermal condition. X-ray diffractometry (XRD) results indicate that these nanocrystallines consist predominantly of anatase TiO(2), with minor amounts of rutile and brookite. Scanning and transmission electron microscopy (SEM and TEM) analyses reveal these rods and hollow tubes may result from the aggregates of nanorods of approximately 10 nm in diameter. The crystallographic faceting found from TEM further reveals the polymorphic nature of the nanocrystalline TiO(2) thus prepared. A "reverse micelle" formation mechanism taking into account the hydrothermal temperature, the pH effect of the sol-gel system, the isoelectric point, the formation of micelles, and the electrostatic interaction between the anionic surfactant and the growing TiO(2) particulates is proposed to illustrate the competition between the physical micelle assembly of the ionic surfactants and the chemical hydrolysis and condensation reactions of the Ti precursors.

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