126
|
Lyles RH, Fan D, Chuachoowong R. Correlation coefficient estimation involving a left censored laboratory assay variable. Stat Med 2001; 20:2921-33. [PMID: 11568949 DOI: 10.1002/sim.901] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
When assessing a correlation between two exposure or biological marker variables, one sometimes encounters the problem of indeterminate values for one of the variables due to an assay detection limit. In this event, investigators often report correlation coefficients computed after removing the pairs involving non-detectable values, or after substituting some small constant for those values. These ad hoc practices can lead to bias in both point and confidence interval estimates of the true correlation coefficient. To address this issue, we consider two parametric techniques for estimating the correlation in the presence of left censoring for one of the variables. The first is a maximum likelihood approach, and the second is an adaptation of multiple imputation motivated primarily by potential benefits in confidence interval coverage. Both of the estimators studied reduce to the standard Pearson's correlation coefficient in the event of no censoring, and hence are valid in cases where this measure would be appropriate for the complete data. We assess these approaches empirically and contrast them with ad hoc methods for estimating the correlation between cervicovaginal human immunodeficiency virus (HIV) viral load measurements and CD4+ lymphocyte counts from HIV positive women enrolled in a clinical trial conducted in Bangkok, Thailand.
Collapse
|
127
|
Houang E, Lam D, Fan D, Seal D. Microbial keratitis in Hong Kong: relationship to climate, environment and contact-lens disinfection. Trans R Soc Trop Med Hyg 2001; 95:361-7. [PMID: 11579873 DOI: 10.1016/s0035-9203(01)90180-4] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Microbial keratitis has been studied in Hong Kong as a representative sub-tropical climate of south China. An 18-month investigation in 1997/98 of 223 cases of ulcerative keratitis (presumed microbial) was conducted in the 2 million population of Shatin and Kowloon at the Prince of Wales and Hong Kong Eye Hospitals respectively with comprehensive microbiology. A case-control study was pursued at the same time between 45 contact-lens wearers (CLW) developing microbial keratitis and 135 lens-wearing volunteers matched for age, sex, educational status and visual acuity. Home water supplies were sampled for Acanthamoeba. Previous ocular surface disease and trauma (preventable by wearing goggles for grinding) were common predisposing causes while cosmetic wear of contact lenses was responsible for 26% of cases overall. Pseudomonas aeruginosa was the commonest bacterium isolated, from both CLW and non-CLW, with infection being acquired within the community. These 28 pseudomonads remained fully sensitive to the third-generation cephalosporins, aminoglycosides and quinolone antibiotics, which is very encouraging. Fungi were isolated, predominantly Fusarium sp., but less commonly than expected. A fungal/bacterial ratio was obtained of 1/17, while in comparison, the expected ratio for a tropical climate ranges from 1/5 (Singapore) to 1/2 (South India). Acanthamoeba was the second commonest microbe isolated from keratitis of CLW. The domestic water environment of 8% of homes of both patients and controls wearing contact lenses was colonized with Acanthamoeba. Lack of hygiene, use of tap water for storing lenses, failure to air-dry lens-storage cases or use of one-step hydrogen peroxide disinfectant were identified as risk factors for keratitis in CLW. The study results commend use of multipurpose solutions by CLW in Hong Kong to achieve the lowest expected rates of infection.
Collapse
|
128
|
Wang X, Wu K, Zhang Z, Lan M, Jin J, Fan D. [The effect of calponin and caldesmon in regulation of the gastrointestinal motility during pathophysiological adaptation]. ZHONGHUA NEI KE ZA ZHI 2001; 40:459-62. [PMID: 11798615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To investigate the expression of calponin (CaP) and caldesmon (CaD) in the gastrointestinal tract and their effect in regulating gastrointestinal motility during physiological and pathological adaptation. METHODS Models of chronic gastrointestinal motility hyperfunction in mice were induced by intragastric administration of senna extraction and models of chronic gastrointestinal motility hypofunction in rats were established with carbon tetrachloride induced cirrhosis, CaP and CaD were detected in the gastrointestinal tract of different model groups using SDS-PAGE and Western blot. The color development of Western blots was scanned using densitometric scanning. The relative contents of gastrointestinal CaP and CaD were compared with control animals with different state of gastrointestinal motility. RESULTS Animal models of abnormal gastrointestinal motility were established in mice and rats. Densitometric quantification of CaP and CaD blots by CP1 and C98 mAbs showed that normal animal colon contained higher amounts of h1-CaP and CaD. In normal mice and rats, the content of CaP and CaD was successively in this order :colon > stomach > small intestine. The content was reduced in mice of chronic gastrointestinal motility hyperfunction, but the expression of CaP and CaD was promoted in rats with cirrhosis and declined to normal level after treatment with L-NAME. CONCLUSION There is close relation between expression of CaP and CaD and state of gastrointestinal motility. CaP and CaD may inhibit gastrointestinal motility. These suggest that CaP and CaD may play a role in the regulation of gastrointestinal motility during physiological and pathological adaptation.
Collapse
|
129
|
Liu X, Ding J, Guo Y, Miao J, Sun A, Fan D. A case of pyrexia, hepatosplenomegaly, cytopenia and hypergammaglobulinemia. Chin Med J (Engl) 2001; 114:207-9. [PMID: 11780210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
|
130
|
Fan D, Reese L, Ren X, Weers PM, Ryan RO, Wang J. Complete 1H, 15N, and 13C assignments of an exchangeable apolipoprotein, Locusta migratoria apolipophorin III. JOURNAL OF BIOMOLECULAR NMR 2001; 19:83-84. [PMID: 11246860 DOI: 10.1023/a:1008398720439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
131
|
Chui WS, Cho P, Fan D. Topographical mapping and in-office modification in the management of an orthokeratology patient. Cont Lens Anterior Eye 2001; 24:121-4. [PMID: 16303465 DOI: 10.1016/s1367-0484(01)80027-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2001] [Revised: 03/19/2001] [Indexed: 10/26/2022]
Abstract
A 20-year-old female was fitted with rigid gas permeable (RGP) orthokeratology (ortho-k) lenses for overnight wear. Both lenses decentred nasally due to the tight fit of the alignment zone (AZ) and the peripheral zone (PZ). The AZ and PZ of both lenses were flattened using an in-office modification unit. Centration of the right lens improved but a small central island was also observed. The left lens still decentred nasally. Both findings indicated that the AZ and PZ of the right lens were too steep leading to 'lens vaulting' or excessive central clearance and inadequate tear exchange, respectively. The AZ and PZ of both lenses were flattened further using the modification unit and after the adjustment, both lenses centred well and the central island in the right eye was eliminated. This case demonstrates the usefulness of topographical corneal mapping and in-office modification of lenses in the management of ortho-k patients.
Collapse
|
132
|
Fan X, Fan D, Gewant H, Royce CL, Nanes MS, Rubin J. Increasing membrane-bound MCSF does not enhance OPGL-driven osteoclastogenesis from marrow cells. Am J Physiol Endocrinol Metab 2001; 280:E103-11. [PMID: 11120664 DOI: 10.1152/ajpendo.2001.280.1.e103] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Macrophage colony-stimulating factor (MCSF) and osteoprotegerin ligand (OPGL), both produced by osteoblasts/stromal cells, are essential factors for osteoclastogenesis. Whether local MCSF levels regulate the amount of osteoclast formation is unclear. Two culture systems, ST-2 and Chinese hamster ovary-membrane-bound MCSF (CHO-mMCSF)-Tet-OFF cells, were used to study the role of mMCSF in osteoclast formation. Cells from bone marrow (BMM) or spleen were cultured with soluble OPGL on glutaraldehyde-fixed cell layers; osteoclasts formed after 7 days. Osteoclast number was proportional to the amount of soluble OPGL added. In contrast, varying mMCSF levels in the ST-2 or CHO-mMCSF-Tet-OFF cell layers, respectively by variable plating or by addition of doxycycline, did not affect BMM osteoclastogenesis: 20-450 U of mMCSF per well generated similar osteoclast numbers. In contrast, spleen cells were resistant to mMCSF: osteoclastogenesis required > or = 250 U per well and further increased as mMCSF rose higher. Our results demonstrate that osteoclast formation in the local bone environment is dominated by OPGL. Increasing mMCSF above basal levels does not further enhance osteoclast formation from BMMs, indicating that mMCSF does not play a dominant regulatory role in the bone marrow.
Collapse
|
133
|
Zhao Y, Xiao B, Chen B, Qiao T, Fan D. Upregulation of drug sensitivity of multidrug-resistant SGC7901/VCR human gastric cancer cells by bax gene transduction. Chin Med J (Engl) 2000; 113:977-80. [PMID: 11776130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
OBJECTIVE To investigate the role of bax in a vincristine (VCR)-induced multidrug-resistant (MDR) human gastric cancer cell line, SGC7901/VCR, in which the Bax protein expression level was significantly lower compared with that in parent cells. METHODS A bax eukaryotic expression vector was constructed and transfected into SGC7901/VCR cells by lipofectamine, and resistant clones were selected by G418. Western blotting detected Bax expression in transfectants. Tetrazolium blue (MTT) assay evaluated the differences in drug sensitivity and cell cycle changes of transfectants were analyzed using flowcytometry (FCM). RESULTS The bax eukaryotic expression vector was constructed and transfected into SGC7901/VCR cells. Through G418 selection, resistant clones were obtained. Western blotting demonstrated that the expression of Bax protein was markedly increased in bax transduced cells. These cells were more sensitive to adriamycin (ADR) and VCR than mock vector transducted cells. Moreover, bax transfection enhanced ADR-induced apoptosis and VCR-induced G2/M phase arrest of SGC7901/VCR cells. CONCLUSION Bax was involved in the MDR of SGC7901/VCR cells.
Collapse
|
134
|
Fan K, Fan D, Cheng LF, Li C. Expression of multidrug resistance-related markers in gastric cancer. Anticancer Res 2000; 20:4809-14. [PMID: 11205224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND To detect the expression of glutathione S-transferase Pi(GST-pi), multidrug resistance-associated protein (MRP), lung-resistance protein(LRP), multidrug resistance gene1 (MDR1) and MGr1 antigen(MGr1-Ag) in the patients with primary gastric cancer and without any prior chemotherapy and to evaluate the correlations between them. PATIENTS AND METHODS The expression of GST-pi, MRP, LRP and MDR1 in cancer tissue and the adjacent non-cancerous tissue from 50 patients was examined by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). The expression of MGr1-Ag in these tissues was also examined by immunohistochemistry. RESULTS The positive rate of GST-pi mRNA, MRP mRNA, LRP mRNA, MDR1mRNA and MGr1-Ag in gastric cancer tissue was 36.00%, 12.00%, 10.00%, 10.00% and 18.00% respectively. The overall positive rate of their expression was 58.00%. Clinicopathological factors were not significantly related to their expression. No significant correlation was observed between these markers. CONCLUSION These MDR markers are differently over-expressed and no coexpression exists in gastric cancer. MGr1-Ag was a novel MDR protein.
Collapse
|
135
|
Shinohara H, Fan D, Ozawa S, Yano S, Van Arsdell M, Viner JL, Beers R, Pastan I, Fidler IJ. Site-specific expression of transferrin receptor by human colon cancer cells directly correlates with eradication by antitransferrin recombinant immunotoxin. Int J Oncol 2000; 17:643-51. [PMID: 10995873 DOI: 10.3892/ijo.17.4.643] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
We determined the efficacy of HB21(Fv)PE40, a single-chain immunotoxin made by fusing the variable regions of a monoclonal antibody directed at the human transferrin receptor (TfR) with a truncated mutant of Pseudomonas exotoxin (PE), against metastatic human colon carcinoma KM12L4 cells growing in the liver or subcutis of nude mice. Organ-specific modulation of TfR expression was examined by immunohistochemistry and flow cytometry using anti-human CD71 antibody. KM12L4 cells expressed human TfR and were lysed in vitro by HB21(Fv)PE40 but not LMB-7 (a control immunotoxin specific for a Lewis Y-related carbohydrate antigen). KM12L4 cells growing in the liver expressed higher levels of TfR than cells growing s.c. Systemic administration of HB21(Fv)PE40 eliminated KM12L4 liver metastasis, whereas administration of LMB-7 did not. Treatment of mice with HB21(Fv)PE40 only delayed the growth of s.c. tumors. KM12L4 cells recovered from liver metastases, expressed higher levels of TfR, and were more sensitive to lysis by HB21(Fv)PE40 than KM12L4 cells recovered from s.c. tumors. Indeed, collectively, the data show that the expression level of the TfR by human colon cancer cells is modulated by the organ microenvironment which can be advantageous for the use of therapeutic immunotoxins.
Collapse
MESH Headings
- Animals
- Antibodies, Monoclonal/genetics
- Antibodies, Monoclonal/immunology
- Antigens, CD/analysis
- Antigens, Differentiation, B-Lymphocyte/analysis
- Cell Survival/drug effects
- Colonic Neoplasms/metabolism
- Colonic Neoplasms/pathology
- Dose-Response Relationship, Drug
- Humans
- Immunoglobulin Fragments/genetics
- Immunoglobulin Fragments/immunology
- Immunohistochemistry
- Immunotoxins/genetics
- Immunotoxins/therapeutic use
- Liver Neoplasms/metabolism
- Liver Neoplasms/prevention & control
- Liver Neoplasms/secondary
- Male
- Mice
- Mice, Nude
- Neoplasm Transplantation
- Neoplasms, Experimental/metabolism
- Neoplasms, Experimental/pathology
- Neoplasms, Experimental/prevention & control
- Receptors, Transferrin/biosynthesis
- Receptors, Transferrin/genetics
- Receptors, Transferrin/immunology
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- Recombinant Fusion Proteins/therapeutic use
- Transplantation, Heterologous
- Tumor Cells, Cultured/cytology
- Tumor Cells, Cultured/drug effects
- Tumor Cells, Cultured/metabolism
- Xenograft Model Antitumor Assays
Collapse
|
136
|
Zhang F, Zhang X, Fan D, Deng Z, Wu H. [Effects of antisense human telomerase RNA on growth of human gastric cancer cells]. ZHONGHUA BING LI XUE ZA ZHI = CHINESE JOURNAL OF PATHOLOGY 2000; 29:367-9. [PMID: 11866938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To observe the inhibitory effects of antisense human telomerase RNA (hTR) on growth of human gastric cancer cells. METHODS SGC7901 cell line was transfected with antisense hTR expression vector (pBBS-hTR) by lipofectAMINE. The gene transfected cells were cultured in vitro and then inoculated into nude mice. RESULTS Antisense hTR expression was enhanced and sense hTR expression inhibited in clones containing antisense hTR after hygromycin resistant selection which induced tumor cells apoptosis. The growth rate of the major gene transfected cells in culture and tumorigenesis of the transfected cells in nude mice were significantly reduced in comparison with those of controls. The survival time of nude mice inoculated with the gene transfected cells was markedly prolonged when compared to controls. CONCLUSIONS The malignant proliferation of gastric cancer cell can be reversed by antisense hTR induced cell apoptosis. Thus antisense hTR may serve as a potential therapeutic approach to the treatment of human cancer.
Collapse
MESH Headings
- Animals
- Cell Division/genetics
- Cell Division/physiology
- Genetic Therapy/methods
- Humans
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Nude
- Microscopy, Electron
- Neoplasm Transplantation
- Neoplasms, Experimental/mortality
- Neoplasms, Experimental/pathology
- Neoplasms, Experimental/therapy
- RNA/genetics
- RNA, Antisense/genetics
- Stomach Neoplasms/genetics
- Stomach Neoplasms/pathology
- Survival Rate
- Telomerase/genetics
- Telomerase/metabolism
- Transplantation, Heterologous
- Tumor Cells, Cultured/metabolism
- Tumor Cells, Cultured/ultrastructure
Collapse
|
137
|
He F, Chen B, Nie Y, Han Z, Qiao T, Fan D. [Production of phage-displayed single chain variable fragments of monoclonal antibody MGb1]. ZHONGHUA NEI KE ZA ZHI 2000; 39:585-7. [PMID: 11798521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To lay a foundation for obtaining a tumor-targeting vehicle for in vivo study on diagnosis and treatment of gastric carcinoma by generating single chain variable fragments (ScFv) of monoclonal antibody MGb1 directed against the cancer. METHODS mRNA was isolated from MGb1-producing mouse hybridoma cell line, and the variable regions of heavy and light chain cDNAs were amplified separately and assembled into ScFv DNAs with a specially constructed linker DNA by PCR. The ScFv DNAs were ligated into the phagemid vector pCANTAB5E and the ligated sample was transformed into competent E. coli TG1. The transformed cells were infected with M13KO7 helper phage to yield recombinant phage, which display ScFv fragments as a fusion with gene 3 protein on the tips of the phage M13. After two rounds of panning with gastric carcinoma cell line KATO III highly expressing MGb1-binding antigen, the phage clones displayed ScFv fragments of the antibody were selected by enzyme-linked immunosorbent assay (ELISA) from the enriched phages. The affinity of the positive phage clones was detected by competition ELISA. RESULTS The VH, VL and ScFv DNAs were about 340 bp, 320 bp and 750 bp respectively. 17 phage clones displayed ScFv of MGb1 were selected from 40 enriched phage clones. 4 out of the 17 phage clones could strongly compete with the original hybridoma antibody MGb1 for binding to the antigen expressed on KATOIII cells. CONCLUSION The phage-displayed ScFv fragments of monoclonal antibody MGb1 are successfully produced by phage antibody technology, which may be useful to widen the range of application of the antibody.
Collapse
|
138
|
Biskobing DM, Fan D. Acid pH increases carbonic anhydrase II and calcitonin receptor mRNA expression in mature osteoclasts. Calcif Tissue Int 2000; 67:178-83. [PMID: 10920224 DOI: 10.1007/s00223001107] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Numerous resorptive stimuli have been shown to enhance osteoclast differentiation, increasing osteoclast numbers and accelerating bone resorption. Currently, there is much less understanding of regulation of mature osteoclast activity. Indeed, there is presently only minimal evidence of changes in gene expression as a mechanism for altering bone resorption. We investigate here, in the mature osteoclast, regulation of 2 genes-carbonic anhydrase II (CAII) and calcitonin receptor (CTR) in response to acidosis, which is known to increase bone resorption. We studied the effect of acid pH on CAII and CTR mRNA expression in mature osteoclasts raised in coculture of ST-2 and primary marrow cells. On day 6 of culture, stromal cells were removed with collagenase, the remaining osteoclasts were incubated overnight, and then exposed to varying pH. RT-PCR was performed on total RNA using primers for CAII, CTR, or glyceraldehyde dehydrogenase phosphate (GAP). Expression of CTR mRNA was increased 2.14 +/- 0.41 and 2.56 +/- 0.45 (P < 0.05)-fold by a 4-hour exposure to pH 6.75 and 6.5, respectively. CAII mRNA was similarly increased 2.18 +/- 0.42 and 2.63 +/- 0.48 (P < 0.05)-fold by pH 6.75 and 6.5, respectively. Increased expression of CAII and CTR mRNA was seen by 2 hours and maximally by 4 hours. Increased expression of CTR and CAII mRNA was not explained by increases in osteoclast numbers: pH 7.4-100 +/- 3.7, 6.75-133 +/- 8.3, 6.5-124 +/- 7.8. These results demonstrate upregulation of two osteoclast genes in response to acidosis, illustrating the ability of the mature osteoclast to respond to resorptive signals with increased functional gene expression.
Collapse
|
139
|
Fan D, Lai W. [Application of studies on popular words in the systematization of ancient medical books]. ZHONGHUA YI SHI ZA ZHI (BEIJING, CHINA : 1980) 2000; 30:151-4. [PMID: 11624687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Based on the arrangement of Renho Temple edition of Taisu (Extremely Plain), as an example, it can be seen that by correcting the wrong popular words in ancient medical books, the causes of mistakes of ancient editions and solution for annotations of difficult terms of ancient words in the medical books are of significance.
Collapse
|
140
|
Li K, Xin Y, Gu Y, Xu B, Fan D, Ni B. Effects of direct current on dog liver: possible mechanisms for tumor electrochemical treatment. Bioelectromagnetics 2000; 18:2-7. [PMID: 9125228 DOI: 10.1002/(sici)1521-186x(1997)18:1<2::aid-bem2>3.0.co;2-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Mechanisms of tumor electrochemical treatment (ECT) were studied using normal dog liver. Five physical and chemical methods were used. Two platinum electrodes were inserted into an anesthetized dog's liver at 3 cm separation. A voltage of 8.5 V direct current (DC) at an average current of 30 mA was applied for 69 min; total charge was 124 coulombs. Concentrations of selected ions near the anode and cathode were measured. The concentrations of Na+ and K+ ions were higher around the cathode, whereas the concentration of Cl- ions was higher around the anode. Water contents and pH were determined near the anode and the cathode at the midpoint between the two electrodes and in an untreated area away from the electrodes. Hydration occurred around the cathode, and dehydration occurred around the anode. The pH values were 2.1 near the anode and 12.9 near the cathode. Spectrophotometric scans of the liver sample extract were obtained, and the released gases were identified by gas chromatography as chlorine at the anode and hydrogen at the cathode. These results indicate that a series of electrochemical reactions take place during ECT. The cell metabolism and its environment are severely disturbed. Both normal and tumor cells are rapidly and completely destroyed in this altered environment. We believe that the above reactions are the ECT mechanisms for treating tumors.
Collapse
|
141
|
Ma Y, Bi X, Ma D, Fan D. [Meckel's diverticulum and its complications in children]. HUNAN YI KE DA XUE XUE BAO = HUNAN YIKE DAXUE XUEBAO = BULLETIN OF HUNAN MEDICAL UNIVERSITY 2000; 23:561-2, 565. [PMID: 10806769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Seventy-two cases of Meckel's diverticulum were treated surgically in recent four years. There were 61 boys and 11 girls with a mean age of 5.2 years. Of the 65 symptomatic patients, 31(43%) had rectal bleeding, 16(23%) suffered from bowel obstruction and 17(24%) peritonitis. Patients with diverticulitis(8 cases) had acute abdominal pain in the periumbilical region or in the right lower quadrant compatible with appendicitis. Ectopic mucosa was found in 47 cases(65.3%). Gastric(36 cases) and pancreatic(11 cases) were the most common ectopic tissues. A nuclear medicine Meckel scan was positive in 26 of 31 patients(84%). It is emphasized that 99mmTcO4- scintiphoto is more specific in diagnosis of the Meckel's diverticulum. The best choice of the surgery is resection of the diverticulum and end-to-end intestinal anastomosis.
Collapse
|
142
|
Bruns CJ, Solorzano CC, Harbison MT, Ozawa S, Tsan R, Fan D, Abbruzzese J, Traxler P, Buchdunger E, Radinsky R, Fidler IJ. Blockade of the epidermal growth factor receptor signaling by a novel tyrosine kinase inhibitor leads to apoptosis of endothelial cells and therapy of human pancreatic carcinoma. Cancer Res 2000; 60:2926-35. [PMID: 10850439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
We determined whether down-regulation of the epidermal growth factor-receptor (EGF-R) signaling pathway by oral administration of a novel EGF-R tyrosine kinase inhibitor (PKI166) alone or in combination with gemcitabine (administered i.p.) can inhibit growth and metastasis of human pancreatic carcinoma cells implanted into the pancreas of nude mice. Therapy beginning 7 days after orthotopic injection of L3.6pl human pancreatic cancer cells reduced the volume of pancreatic tumors by 59% in mice treated with gemcitabine only, by 45% in those treated with PKI166 only, and by 85% in those given both drugs. The combination therapy also significantly inhibited lymph node and liver metastasis, which led to a significant increase in overall survival. EGF-R activation was significantly blocked by therapy with PKI166 and was associated with significant reduction in tumor cell production of VEGF and IL-8, which in turn correlated with a significant decrease in microvessel density and an increase in apoptotic endothelial cells. Collectively, our results demonstrate that oral administration of an EGF-R tyrosine kinase inhibitor decreased growth and metastasis of human pancreatic cancer growing orthotopically in nude mice and increased survival. The therapeutic effects were mediated in part by inhibition of tumor-induced angiogenesis attributable to a decrease in production of proangiogenic molecules by tumor cells and increased apoptosis of tumor-associated endothelial cells.
Collapse
|
143
|
Yang J, Fan D, Wang S, Gu Y. Moiré technique for spatial coherence measurements of soft-x-ray lasers. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2000; 17:790-793. [PMID: 10757188 DOI: 10.1364/josaa.17.000790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present a novel moiré diagnostic that allows the time-averaged spatial coherence properties of soft-x-ray lasers to be measured. The technique is an extension of the theoretical work in a recent paper [J. Opt. Soc. Am. A 16, 323 (1999)] and is based on the concept of decompositions of the far-field divergence for partially coherent beams. An appealing feature of the approach is that the spatial coherence width at other planes can be evaluated from the measured one at a given plane on the assumption of shape-invariant beams.
Collapse
|
144
|
Rubin J, Fan D, Wade A, Murphy TC, Gewant H, Nanes MS, Fan X, Moerenhout M, Hofstetter W. Transcriptional regulation of the expression of macrophage colony stimulating factor. Mol Cell Endocrinol 2000; 160:193-202. [PMID: 10715553 DOI: 10.1016/s0303-7207(99)00212-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The regulatory regions for transcriptional control of the MCSF gene are unknown. We examined regulatory control in a 774-bp murine MCSF promoter transfected into MC3T3-E1 osteoblast-like and COS-7 cells. Deletion of upstream sequence from -635 increased basal activity of the promoter by at least four-fold, an increase that was maintained when PU.1, NFkappaB and Egr1/Sp1 consensus sequences were subsequently removed. Mutagenesis identified a suppressor element between -635 and -642 from the transcriptional start site and an oligonucleotide representing this sequence was retarded by nuclear cell protein. TNFalpha (1 ng/ml), PTH (5x10(-8) M), and IL-1alpha (100 pg/ml), which increased MCSF protein secretion, failed to enhance the transcriptional rate of the full-length promoter. TNFalpha was able to stimulate transcription of a heterologous reporter transfected into COS-7 containing multiple copies of the murine MCSF NFkappaB site inserted before a minimal promoter. In contrast, deletion of the same NFkappaB response element increased basal activity in the native promoter. Thus, the NFkappaB sequence may act as a negative regulator in the context of the endogenous promoter. Our results indicate that constitutive transcriptional activity conferred by the MCSF promoter may be damped by a suppressor protein. Transcriptional regulation, however, does not appear to be a major stimulatory mechanism for MCSF secretion.
Collapse
|
145
|
Rohanizadeh R, LeGeros RZ, Fan D, Jean A, Daculsi G. Ultrastructural properties of laser-irradiated and heat-treated dentin. J Dent Res 1999; 78:1829-35. [PMID: 10598913 DOI: 10.1177/00220345990780121001] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Previous studies using scanning electron microscopy and infrared absorption spectroscopy reported that laser irradiation causes compositional changes in enamel. The purpose of this study was to evaluate the ultrastructural and compositional changes in dentin caused by irradiation with a short-pulse laser (Q-switched Nd:YAG). The irradiated and non-irradiated areas of the lased dentin samples were investigated by scanning (SEM) and transmission electron microscopy (TEM), micro-micro electron diffraction, and electron microprobe analysis of dispersive energy (EDX). Heat-treated dentin was similarly investigated. This study demonstrated that laser irradiation resulted in the recrystallization of dentin apatite and in the formation of additional calcium phosphate phases consisting of magnesium-substituted beta-tricalcium phosphate, beta-TCMP, beta-(Ca,Mg)3(PO4)2, and tetracalcium phosphate, TetCP, Ca4(PO4)O. TEM analyses of the modified and unmodified zones of the irradiated areas showed two types of crystal populations: much larger crystals from the modified zone and crystals with size and morphology similar to those of dentin apatite in the unmodified zone. The morphology of crystals in the modified zones in the irradiated dentin resembled those of dentin sintered at 800 or 950 degrees C. In the irradiated areas (modified and unmodified zones), the Ca/P ratio was lower compared with that in the non-irradiated dentin. The Mg/Ca ratio in the modified zones was higher than that in the unmodified zones and in the non-irradiated dentin. In sintered dentin, the Mg/Ca ratio increased as a function of sintering temperature. The ultrastructural and compositional changes observed in laser-irradiated dentin may be attributed to high temperature and high pressure induced by microplasma during laser irradiation. These changes may alter the solubility of the irradiated dentin, making it less susceptible to acid dissolution or to the caries process.
Collapse
|
146
|
Liu X, Ye L, Wang J, Fan D. Expression of heat shock protein 90 beta in human gastric cancer tissue and SGC7901/VCR of MDR-type gastric cancer cell line. Chin Med J (Engl) 1999; 112:1133-7. [PMID: 11721455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
OBJECTIVE To examine the expression of heat shock protein (HSP) 90 beta in human gastric cancer tissue and SGC7901/VCR of MDR-type gastric cancer cell line. METHODS Immunohistochemical staining and in situ hybridization methods. RESULTS Heat shock protein 90 beta was mainly located in the cell cytoplasma and weakly expressed in non-cancerous gastric mucosa. The expression rates of HSP90 beta in normal gastric mucosa, gastritis and paracancer tissues were 11.76%, 13.04% and 11.42% respectively, and there were no significant differences between them (P > 0.05). The expression of HSP90 beta was increased in gastric cancer. The positive rate of HSP90 beta in gastric cancer tissue was 30.00%, and was higher than non-cancerous gastric mucosa (P < 0.05). The expression rates of HSP90 beta in well differentiated, moderately differentiated, poorly differentiated gastric cancer and mucinous carcinoma were 15.38%, 31.25%, 33.33%, and 42.85% respectively. The expression of HSP90 beta in SGC7901/VCR of MDR-type gastric cell line was higher than in its parental cell line SGC7901. In situ hybridization showed that the positive signal of HSP90 beta was mainly located in the cell cytoplasma. CONCLUSIONS The expression of HSP90 beta was higher in gastric cancer tissue than in non-cancerous gastric mucosa. In gastric cancer tissue, the expression of HSP90 beta was greater in poorly differentiated cancer tissue, and in SGC7901/VCR of MDR-type gastric cancer cell line the expression of HSP90 beta was higher than that in its parental cell line SGC7901.
Collapse
|
147
|
Multani AS, Ozen M, Sen S, Mandal AK, Price JE, Fan D, Radinsky R, Ali-Osman F, Von Eschenbach AC, Fidler IJ, Pathak S. Amplification of telomeric DNA directly correlates with metastatic potential of human and murine cancers of various histological origin. Int J Oncol 1999; 15:423-9. [PMID: 10427120 DOI: 10.3892/ijo.15.3.423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Telomeres, repeated DNA sequences (T2AG3)n that guard the ends of chromosomes, serve as a checkpoint for cell-cycle progression and regulate cell senescence and apoptosis. Loss of the telomeric repeats promotes genomic instability, which is the hallmark of most cancer cells. Whether this loss differs among tumor cells with malignant potential is unknown and was the goal of this study. An all-human telomeric DNA probe was used to perform fluorescence in situ hybridization (FISH) and the telomeric signals in interphase nuclei were quantitated using a computer software package. Southern blot analysis was carried out to measure terminal restriction fragment length (TRFL) in multiple cancer cell lines, including nonmetastatic and metastatic human breast, lung, prostate, colon, brain, and renal carcinomas, as well as human and murine melanoma clones and somatic cell hybrids. The metastatic capability of all cell lines, clones and somatic cell hybrids was evaluated subsequent to orthotopic implantation into nude mice. FISH preparations with telomeric DNA probes showed that the mean percent telomeric area in the metastatic nuclei was significantly greater than their nonmetastatic counterparts and Southern blotting in selected samples confirmed our findings. These data suggest that amplification of telomeres is directly correlated with invasive and metastatic potential of murine or human tumor cells.
Collapse
|
148
|
Fan D, Grooms SY, Araneda RC, Johnson AB, Dobrenis K, Kessler JA, Zukin RS. AMPA receptor protein expression and function in astrocytes cultured from hippocampus. J Neurosci Res 1999; 57:557-71. [PMID: 10440906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Glutamate receptors guide the proliferation, migration, and differentiation of glial cells. Here, we characterize AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid) and NMDA receptor protein expression and function and mRNA expression in hippocampal glial cultures. By immunocytochemistry, GluR2 (the subunit that limits the Ca(2+) permeability of AMPA receptors) exhibited prominent labeling in hippocampal glial cultures. Double-labeling of GluR2 with GFAP and with A2B5 revealed GluR2 subunit expression on type-1 and type-2 astrocyte lineage cells. GluR1 subunit expression was more prominent in type-1 than in type-2 astrocytes. To characterize functional properties of glutamate receptors expressed in cultured hippocampal astrocytes, we performed whole-cell patch clamp recording. Application of L-glutamate, AMPA, and kainate, but not NMDA, to small, rounded cells (morphologically identified as type-2 astrocytes) elicited inward currents which were blocked by the AMPA/kainate antagonist 6-cyano-7-nitroquinoxaline-2, 3-dione (CNQX). Cyclothiazide potentiated AMPA- and kainate-elicited currents, indicative of AMPA-preferring receptors. Current voltage analysis indicated that type-2 astrocyte AMPA receptors were electrically linear, indicative of GluR2-containing, Ca(2+)-impermeable AMPA receptors. By Northern blot analysis, GluR1 mRNA was highest in astrocyte cultures from cerebellum and hippocampus and moderate in astrocyte cultures from neocortex and striatum. GluR3 mRNA was detectable in astrocyte cultures from cerebellum and neocortex. GluR2 and NR1 mRNA expression were not detected in astrocytes cultured from any brain region examined. In situ hybridization studies showed wide expression of GluR1 mRNA in cultured astrocytes; GluR2 and GluR3 mRNAs were near background levels. Thus, cultured type-2 astrocytes express functional AMPA receptors in a cell-specific and region-specific manner, consistent with their role in neuronal-glial communication.
Collapse
|
149
|
Norris JD, Paige LA, Christensen DJ, Chang CY, Huacani MR, Fan D, Hamilton PT, Fowlkes DM, McDonnell DP. Peptide antagonists of the human estrogen receptor. Science 1999; 285:744-6. [PMID: 10426998 DOI: 10.1126/science.285.5428.744] [Citation(s) in RCA: 304] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Estrogen receptor alpha transcriptional activity is regulated by distinct conformational states that are the result of ligand binding. Phage display was used to identify peptides that interact specifically with either estradiol- or tamoxifen-activated estrogen receptor alpha. When these peptides were coexpressed with estrogen receptor alpha in cells, they functioned as ligand-specific antagonists, indicating that estradiol-agonist and tamoxifen-partial agonist activities do not occur by the same mechanism. The ability to regulate estrogen receptor alpha transcriptional activity by targeting sites outside of the ligand-binding pocket has implications for the development of estrogen receptor alpha antagonists for the treatment of tamoxifen-refractory breast cancers.
Collapse
|
150
|
Isaacs SD, Fan X, Fan D, Gewant H, Murphy TC, Farmer P, Taylor WR, Nanes MS, Rubin J. Role of NFkappaB in the regulation of macrophage colony stimulating factor by tumor necrosis factor-alpha in ST2 bone stromal cells. J Cell Physiol 1999; 179:193-200. [PMID: 10199558 DOI: 10.1002/(sici)1097-4652(199905)179:2<193::aid-jcp9>3.0.co;2-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Expression of MCSF in bone is important to the regulation of osteoclastogenesis. We show here that tumor necrosis factor-alpha (TNFalpha) increases the production of both soluble (sMCSF) and membrane-bound (mMCSF) macrophage colony stimulating factor by ST2 bone stromal cells. Treatment of ST2 cells with TNFalpha caused sMCSF levels to increase by 394+/-5% from basal; mMCSF rose by 316+/-66% from 30+/-10 per 100,000 cells in the same time. These increases were consistent with increased expression of mRNAs encoding both isoforms. Increases in MCSF mRNA are also seen after stimulation with dexamethasone. To investigate the potential role of NFkappaB in this TNFalpha effect, we treated cells with sodium salicylate (NaS), an inhibitor of NFkappaB translocation. NaS decreased TNFalpha-stimulated NFkappaB activation by 50% as assessed by EMSA. Despite inhibition of NFkappaB signaling, NaS enhanced TNFalpha-stimulated MCSF secretion and did not prevent TNFalpha-stimulated increases in sMCSF mRNA, suggesting that NFkappaB was not involved in TNFalpha effect on the gene. TNFalpha failed to stimulate transcription of a 774 nucleotide MCSF promoter-luciferase reporter transfected into ST2 cells which contained the NFkappaB consensus sequence. Deletion of the seven nucleotides containing the NFkappaB homology response sequence from the MCSF promoter increased basal gene transcription by twofold. TNFalpha thus contributes to an osteoclastogenic environment through upregulation of bone expression of both MCSF isoforms. Our data suggests that NFkappaB is not the major signaling pathway through which this occurs.
Collapse
|