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Abstract
CONTEXT Previous studies have suggested that minority medical school faculty are at a disadvantage in promotion opportunities compared with white faculty. OBJECTIVE To compare promotion rates of minority and white medical school faculty in the United States. DESIGN AND SETTING Analysis of data from the Association of American Medical Colleges' Faculty Roster System, the official data system for tracking US medical school faculty. PARTICIPANTS A total of 50,145 full-time US medical school faculty who became assistant professors or associate professors between 1980 and 1989. Faculty of historically black and Puerto Rican medical schools were excluded. MAIN OUTCOME MEASURES Attainment of associate or full professorship among assistant professors and full professorship among associate professors by 1997, among white, Asian or Pacific Islander (API), underrepresented minority (URM; including black, Mexican American, Puerto Rican, Native American, and Native Alaskan), and other Hispanic faculty. RESULTS By 1997, 46% of white assistant professors (13,479/28,953) had been promoted, whereas 37% of API (1123/2997; P<.001), 30% of URM (311/1053, P<.001), and 43% of other Hispanic assistant professors (256/598; P =.07) had been promoted. Similarly, by 1997, 50% of white associate professors (7234/14,559) had been promoted, whereas 44% of API (629/1419; P<.001), 36% of URM (101/280; P<.001), and 43% of other Hispanic (122/286; P =.02) associate professors had been promoted. Racial/ethnic disparities in promotion were evident among tenure and nontenure faculty and among faculty who received and did not receive National Institutes of Health research awards. After adjusting for cohort, sex, tenure status, degree, department, medical school type, and receipt of NIH awards, URM faculty remained less likely to be promoted compared with white faculty (relative risk [RR], 0.68 [99% confidence interval CI, 0.59-0.77] for assistant professors and 0.81 [99% CI, 0.65-0.99] for associate professors). API assistant professors also were less likely to be promoted (RR, 0.91 [99% CI, 0.84-0.98]), whereas API associate professors and other Hispanic assistant and associate professors were promoted at comparable rates. CONCLUSION Our data indicate that minority faculty are promoted at lower rates compared with white faculty. JAMA. 2000;284:1085-1092
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Qiu L, Joazeiro C, Fang N, Wang HY, Elly C, Altman Y, Fang D, Hunter T, Liu YC. Recognition and ubiquitination of Notch by Itch, a hect-type E3 ubiquitin ligase. J Biol Chem 2000; 275:35734-7. [PMID: 10940313 DOI: 10.1074/jbc.m007300200] [Citation(s) in RCA: 251] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Genetic studies identified Itch, which is a homologous to the E6-associated protein carboxyl terminus (Hect) domain-containing E3 ubiquitin-protein ligase that is disrupted in non-agouti lethal mice or Itchy mice. Itch-deficiency results in abnormal immune responses and constant itching in the skin. Here, Itch was shown to associate with Notch, a protein involved in cell fate decision in many mammalian cell types, including cells in the immune system. Itch binds to the N-terminal portion of the Notch intracellular domain via its WW domains and promotes ubiquitination of Notch through its Hect ubiquitin ligase domain. Thus, Itch may participate in the regulation of immune responses by modifying Notch-mediated signaling.
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Fang D, Liu YC. Proteolysis-independent regulation of PI3K by Cbl-b-mediated ubiquitination in T cells. Nat Immunol 2001; 2:870-5. [PMID: 11526404 DOI: 10.1038/ni0901-870] [Citation(s) in RCA: 234] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cbl-b, a ring-type E3 ubiquitin protein ligase, is implicated in setting the threshold of T lymphocyte activation. The p85 regulatory subunit of phosphatidylinositol 3 kinase (PI3K) was identified as a substrate for Cbl-b. We have shown that Cbl-b negatively regulated p85 in a proteolysis-independent manner. Cbl-b is involved in the recruitment of p85 to CD28 and T cell antigen receptor zeta through its E3 ubiquitin ligase activity. The enhanced activation of Cbl-b(-/-) T cells was suppressed by the inhibition of PI3K. The results suggest a proteolysis-independent function for Cbl-b in the modification of protein recruitment.
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Wang S, Liu Y, Fang D, Shi S. The miniature pig: a useful large animal model for dental and orofacial research. Oral Dis 2008; 13:530-7. [PMID: 17944668 DOI: 10.1111/j.1601-0825.2006.01337.x] [Citation(s) in RCA: 220] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Compared with small animal models such as rodents, large animal models are superior in many aspects for the study of human diseases and pre-clinical therapies. Since the development of the Minnesota miniature pig in 1949 at the Hormel Institute (USA), miniature pigs have been used as a large animal model in medical studies for scientific, economic, and ethical reasons. The oral maxillofacial region of miniature pigs is similar to that of humans in anatomy, development, physiology, pathophysiology, and disease occurrence. In this review, we describe the anatomical characteristics of the oral maxillofacial system of the miniature pig, established models of oral diseases in this animal, and other uses of the miniature pig in orofacial research.
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Fang D, Wang HY, Fang N, Altman Y, Elly C, Liu YC. Cbl-b, a RING-type E3 ubiquitin ligase, targets phosphatidylinositol 3-kinase for ubiquitination in T cells. J Biol Chem 2001; 276:4872-8. [PMID: 11087752 DOI: 10.1074/jbc.m008901200] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cbl-b is implicated in setting the threshold of T lymphocyte activation. In Cbl-b-deficient T cells, the activation of Vav, a guanine nucleotide exchange factor, is significantly enhanced. The molecular mechanism underlying Cbl-b-regulated Vav activation was unclear. Here it is shown that Cbl-b interacts with and induces ubiquitin conjugation to the p85 regulatory subunit of phosphatidylinositol 3-kinase, an upstream regulator of Vav. A functional RING finger of Cbl-b was essential for p85 ubiquitination. However, a loss of function mutation at the well-conserved amino-terminal variant src homology (SH) 2 domain of Cbl-b did not affect its ligase activity. A distal carboxyl-terminal proline-rich region in Cbl-b was mapped to contain the primary binding sequences for the SH3 domain of p85. Deletion of either the distal proline-rich region in Cbl-b or the SH3 domain of p85 severely reduced ubiquitin conjugation to p85. The data suggest a molecular link for Cbl-b-mediated negative regulation of Vav, with phosphatidylinositol 3-kinase as a direct target for Cbl-b E3 ubiquitin ligase.
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Wang HY, Altman Y, Fang D, Elly C, Dai Y, Shao Y, Liu YC. Cbl promotes ubiquitination of the T cell receptor zeta through an adaptor function of Zap-70. J Biol Chem 2001; 276:26004-11. [PMID: 11353765 DOI: 10.1074/jbc.m010738200] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Triggering of the T cell antigen receptor (TCR).CD3 complex induces its ubiquitination. However, the molecular events that lead to ubiquitin conjugation to these cell surface molecules have not been defined. Here we report that Cbl, a RING-type E3 ubiquitin-protein ligase, promotes ubiquitination of TCR zeta chain, which requires its functional variant Src homology 2 domain and an intact RING finger. The tyrosine kinase Zap-70, which binds to both TCR zeta and Cbl, plays an adaptor role in these events. Mutations in TCR zeta, Zap-70, or Cbl that disrupt the interaction between TCR zeta and Zap-70 or between Zap-70 and Cbl reduce ubiquitination of TCR zeta. Our results suggest a novel mechanism by which Cbl negatively regulates T cell development and activation by inducing ubiquitination of the TCR.CD3 components.
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Research Support, U.S. Gov't, P.H.S. |
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Lee SM, Yang H, Tartar DM, Gao B, Luo X, Ye SQ, Zaghouani H, Fang D. Prevention and treatment of diabetes with resveratrol in a non-obese mouse model of type 1 diabetes. Diabetologia 2011; 54:1136-46. [PMID: 21340626 PMCID: PMC4036531 DOI: 10.1007/s00125-011-2064-1] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 12/23/2010] [Indexed: 12/15/2022]
Abstract
AIMS/HYPOTHESIS We recently found that activation of the type III histone deacetylase sirtuin 1 suppresses T cell immune responses. Here we sought to determine the therapeutic potential of the sirtuin 1 activator resveratrol in the treatment of diabetes in the NOD mouse model of type 1 diabetes and the mechanisms underlying such potential. METHODS NOD mice were fed or subcutaneously injected with resveratrol and evaluated for development of diabetes. Splenocytes from resveratrol-treated and control mice were analysed by gene array. The altered expression of inflammatory genes induced by resveratrol was validated and the role of changed gene expression in prevention of diabetes was determined. RESULTS Resveratrol administration potently prevented and treated type 1 diabetes in NOD mice. Gene array analysis indicated a dramatic decrease in expression of Ccr6, which encodes chemokine (C-C motif) receptor (CCR) 6, in the splenocytes from resveratrol-treated mice. CCR6 abundance on IL-17-producing cells and CD11b(+)F4/80(hi) macrophages was inhibited by resveratrol treatment. Interestingly, CCR6(+) IL-17-producing cells and CD11b(+)F4/80(hi) macrophages accumulated in the spleens and pancreatic lymph nodes, but their presence in the pancreas was reduced, suggesting that resveratrol blocks their migration from peripheral lymphoid organs to the pancreas. Indeed, the migration of splenocytes toward media containing chemokine (C-C motif) ligand 20 (CCL20) was impaired by resveratrol treatment. CCL20 peptides, which block CCR6 binding to CCL20, inhibited development of type 1 diabetes. CONCLUSIONS/INTERPRETATION Inhibition of CCR6-mediated migration of inflammatory cells by resveratrol may provide a powerful approach for treatment of type 1 diabetes and possibly of other inflammatory diseases.
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Research Support, N.I.H., Extramural |
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Pun WK, Chow SP, Fang D, Cheng CL, Leong JC, Ng C. Post-traumatic oedema of the foot after tibial fracture. Expert Rev Mol Diagn 1990; 15:735-47. [PMID: 2592102 DOI: 10.1586/14737159.2015.1039515] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A total of 97 patients with diaphyseal tibial fractures treated with functional bracing were studied prospectively. Persistent ipsilateral foot swelling was present in 84.5 per cent of the patients. Most of the swellings subsided with time, but a small percentage of them persisted for a duration of 2 years or more after injury. The time for disappearance of the swelling in 50 per cent of the patients was 18.6 weeks. The development of oedema is not related to the age and sex of the patients, the configuration, type and level of the fractures, or the association of a fibular fracture. The bone healed quicker in those who did not have swelling of the foot. Once the swelling has developed, it seems to run its own course and its disappearance is not related to the age and sex, the configuration, type and level of fractures, the association of a fibular fracture, or the time for fracture healing. This complication does not have any adverse effect on the functional recovery of the patients.
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Li X, Wang E, Yin B, Fang D, Chen P, Wang G, Zhao J, Zhang H, Chen W. Effects of Lactobacillus casei CCFM419 on insulin resistance and gut microbiota in type 2 diabetic mice. Benef Microbes 2017; 8:421-432. [PMID: 28504567 DOI: 10.3920/bm2016.0167] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The antidiabetic effect of Lactobacillus is increasingly recognized worldwide. In this research, the hypoglycemic activity of Lactobacillus casei CCFM419 was investigated in mice with high-fat and low-dose streptozotocin induced type 2 diabetes. Oral L. casei CCFM419 administration favourably regulated blood glucose balance, increased glucose tolerance and protected islets in the diabetic mice, accompanied by an improvement in lipid metabolism. The homeostasis model of insulin resistance, insulin level and insulin tolerance test and mRNA expression of PI3K/Akt signalling pathway indexes revealed that L. casei CCFM419 had a positive effect on insulin resistance. Furthermore, treatment with L. casei CCFM419 recovered the level of short-chain fatty acids and increased the abundance of butyrate-producing bacteria, such as Allobaculum and Bacteriodes. These results demonstrated that L. casei CCFM419 had the potential ability to ameliorate insulin resistance and hyperglycaemic in type 2 diabetic mice through underlying PI3K/Akt signalling pathway and short-chain fatty acids/gut microbiota pathways.
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Abstract
A series of 40 patients is presented at least ten years following anterior spinal fusion for intervertebral disc prolapse. The proportion of patients who had complete relief or only isolated transient symptoms at the five-year review (67.5%) showed only a very slight fall over the years (65.0%). The union rate was shown to improve with time. There was no clear evidence that anterior spinal fusion led to accelerated degeneration of adjacent intervertebral discs. The significance of posterior extension of the fusion is discussed.
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Fang D, Leong JC, Fang HS. Tuberculosis of the upper cervical spine. THE JOURNAL OF BONE AND JOINT SURGERY. BRITISH VOLUME 1983; 65:47-50. [PMID: 6822601 DOI: 10.1302/0301-620x.65b1.6822601] [Citation(s) in RCA: 78] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Six patients, aged between 3 and 51 years, with tuberculosis of the upper cervical spine were studied. Prominent features of the disease included pain and stiffness, paralysis, swelling of the retropharyngeal soft tissue, osteolytic erosions, and atlanto-axial subluxation. Cure was obtained with antibiotics, transoral decompression and C1-2 fusion.
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Fang D, Setaluri V. Expression and Up-regulation of alternatively spliced transcripts of melastatin, a melanoma metastasis-related gene, in human melanoma cells. Biochem Biophys Res Commun 2000; 279:53-61. [PMID: 11112417 DOI: 10.1006/bbrc.2000.3894] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Loss of expression of a novel suppressor of metastasis, melastatin (MLSN1), has recently been reported to correlate with metastatic potential of melanoma cells. Using differential display analysis, we identified MLSN1 among genes overexpressed in pigmented metastatic human melanoma cells treated with the differentiation inducer hexamethylene bisacetamide (HMBA). In this study, we show that multiple short transcripts of MLSN1 are present in melanocytes and pigmented metastatic melanoma cell lines while the full-length 5. 4-kb mRNA is detectable only in melanocytes. Treatment of pigmented melanoma cells with the differentiation-inducing agent, HMBA, results in up-regulation of the 5.4-kb MLSN1 mRNA as well as short RNAs. Analysis of a panel of nonpigmented primary and metastatic melanoma cell lines showed weak expression of a 1.8-kb mRNA in a few melanoma cell lines. Northern blot and RT-PCR analyses with DNA probes and oligonucleotide primers that correspond to distinct regions of full-length MLSN1 mRNA indicated that the short transcripts contained sequences corresponding primarily to either 5'- or 3'-end of the 5.4-kb mRNA. HMBA appears to up-regulate MLSN1 transcripts derived mainly from the 5'-end. Modulators of cAMP and protein kinase C pathways had no significant effect on MLSN1 expression. Our data show that multiple MLSN1 transcripts, both constitutively expressed and inducible, are present in cultured pigmented melanoma cells, and suggest that MLSN1 expression can be regulated at the level of both transcription and mRNA processing.
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Abstract
Only four established odontoblast-like cell lines have been reported in the literature (1-6). Of the four, only two synthesize dentin-specific proteins. These studies report that the cell line MO6-G3 synthesizes phosphophoryn (DPP), dentin sialoprotein (DSP) and dentin matrix protein-1 (DMP-1) while MDPC-23 synthesizes DSP, but not DMP-1. The objective of the present study was to determine whether polyclonal antibodies to rat DSP and DPP would label odontoblasts on microscopic sections of day-19 fetal mouse incisor odontoblasts as well as cultured cells of the MDPC-23 cell line. The spontaneously immortalized MDPC-23 cell line was derived from fetal mouse molar papillae, made continuous by the 3T6 method and cloned by dilution. These cultures have been passaged 77 times after cloning, form multilayered nodules, and have high alkaline phosphatase activity. The data show positive reactivity in odontoblasts in 19-d mouse fetal incisors as well as in cultures of MDPC-23 cells by fluorescence and confocal microscopy. In addition, these cultures were characterized by phase microscopy and scanning and transmission electron microscopy. These findings suggest that MDPC-23 cells are of the odontoblast lineage.
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Li X, Wang N, Yin B, Fang D, Jiang T, Fang S, Zhao J, Zhang H, Wang G, Chen W. Effects of Lactobacillus plantarum CCFM0236 on hyperglycaemia and insulin resistance in high-fat and streptozotocin-induced type 2 diabetic mice. J Appl Microbiol 2017; 121:1727-1736. [PMID: 27552342 DOI: 10.1111/jam.13276] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 07/31/2016] [Accepted: 08/15/2016] [Indexed: 01/10/2023]
Abstract
AIMS The aim of this study was to rapidly screen potential hypoglycaemic strain by α-glucosidase inhibitory activity in vitro, then explored the antidiabetic effect of Lactobacillus plantarum CCFM0236 in vivo. METHODS AND RESULTS The cell-free supernatant of Lact. plantarum CCFM0236 significantly inhibited α-glucosidase activity in vitro. Therefore, the effects of Lact. plantarum CCFM0236, with potential hypoglycaemia activity, on insulin resistance and hyperglycaemia were explored in high-fat and streptozotocin-induced type 2 diabetes mice. Oral administration of Lact. plantarum CCFM0236 was found to decrease food intake, blood glucose level, glycosylated haemoglobin level and leptin level. Treatments of Lact. plantarum CCFM0236 also favourably regulated insulin level, AUCglucose , and HOMA-IR index, and increased the activities of glutathione peroxidase and the levels of glutathione, high-density lipoprotein cholesterol and interleukin-10. In addition, Lact. plantarum CCFM0236 reduced levels of malondialdehyde and tumour necrosis factor-α and protected pancreas function. CONCLUSIONS Lactobacillus plantarum CCFM0236 has potential hypoglycaemic ability by ameliorating insulin resistance, antioxidant capacity and systemic inflammation in mice. SIGNIFICANCE AND IMPACT OF THE STUDY The method of α-glucosidase inhibitory activity could be effectively used to screen potential hypoglycaemic products and Lact. plantarum CCFM0236 might be a promising therapeutic agent for ameliorating type 2 diabetes.
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Heslop KA, Rovini A, Hunt EG, Fang D, Morris ME, Christie CF, Gooz MB, DeHart DN, Dang Y, Lemasters JJ, Maldonado EN. JNK activation and translocation to mitochondria mediates mitochondrial dysfunction and cell death induced by VDAC opening and sorafenib in hepatocarcinoma cells. Biochem Pharmacol 2020; 171:113728. [PMID: 31759978 PMCID: PMC7309270 DOI: 10.1016/j.bcp.2019.113728] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/20/2019] [Indexed: 02/07/2023]
Abstract
The multikinase inhibitor sorafenib, and opening of voltage dependent anion channels (VDAC) by the erastin-like compound X1 promotes oxidative stress and mitochondrial dysfunction in hepatocarcinoma cells. Here, we hypothesized that X1 and sorafenib induce mitochondrial dysfunction by increasing reactive oxygen species (ROS) formation and activating c-Jun N-terminal kinases (JNKs), leading to translocation of activated JNK to mitochondria. Both X1 and sorafenib increased production of ROS and activated JNK. X1 and sorafenib caused a drop in mitochondrial membrane potential (ΔΨ), a readout of mitochondrial metabolism, after 60 min. Mitochondrial depolarization after X1 and sorafenib occurred in parallel with JNK activation, increased superoxide (O2•-) production, decreased basal and oligomycin sensitive respiration, and decreased maximal respiratory capacity. Increased production of O2•- after X1 or sorafenib was abrogated by JNK inhibition and antioxidants. S3QEL 2, a specific inhibitor of site IIIQo, at Complex III, prevented depolarization induced by X1. JNK inhibition by JNK inhibitors VIII and SP600125 also prevented mitochondrial depolarization. After X1, activated JNK translocated to mitochondria as assessed by proximity ligation assays. Tat-Sab KIM1, a peptide selectively preventing the binding of JNK to the outer mitochondrial membrane protein Sab, blocked the depolarization induced by X1 and sorafenib. X1 promoted cell death mostly by necroptosis that was partially prevented by JNK inhibition. These results indicate that JNK activation and translocation to mitochondria is a common mechanism of mitochondrial dysfunction induced by both VDAC opening and sorafenib.
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Research Support, N.I.H., Extramural |
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Fang D, Leong JC, Ho EK, Chan FL, Chow SP. Spinal pseudarthrosis in ankylosing spondylitis. Clinicopathological correlation and the results of anterior spinal fusion. THE JOURNAL OF BONE AND JOINT SURGERY. BRITISH VOLUME 1988; 70:443-7. [PMID: 3372569 DOI: 10.1302/0301-620x.70b3.3372569] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We reviewed 40 extensive destructive vertebral lesions in 35 patients with established ankylosing spondylitis. Of these, 31 had presented with localised pain while three had a neurological deficit. The radiographs suggested ununited fractures through either ankylosed discs (37) or vertebral bodies (3). Corresponding fractures were seen in the posterior column in 34 cases. Sixteen patients with 18 lesions underwent anterior spinal fusion, and pseudarthrosis was consistently proven by histopathology. Two pseudarthroses healed in conservatively treated patients. Thirteen of the operated patients were followed for an average of 7 years 7 months. There were two cases of non-union and one required an additional posterior fusion; in the remainder fusion was sound.
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Fang D, Kute T, Setaluri V. Regulation of tyrosinase-related protein-2 (TYRP2) in human melanocytes: relationship to growth and morphology. PIGMENT CELL RESEARCH 2001; 14:132-9. [PMID: 11310793 DOI: 10.1034/j.1600-0749.2001.140209.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Treatment of human melanoma cells with the differentiation-inducing agent hexamethylene bisacetamide (HMBA) results in reciprocal changes in expression of melanocyte-specific genes tyrosinase-related proteins-1 and -2 (TYRP1 and TYRP2). In this study, we investigated the effects of HMBA on cultured neonatal human cutaneous melanocytes. Flow cytometric analysis showed that HMBA inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-dependent growth of melanocytes by reducing the population of cells entering the DNA synthesis phase of cell cycle. Melanocyte growth inhibition was accompanied by an increase in the number of cells exhibiting polydendritic morphology. This morphologic change was less pronounced when HMBA was added to melanocytes in the absence of TPA. Northern blot analyses of total cellular RNA showed that expression of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), TYRP1, Silver (SILV/Pmel17) gene was down-regulated by HMBA, while TYRP2 mRNA was up-regulated (> 10-fold). When the inducer was added to cells in the absence of TPA, there was > 50-fold increase in TYRP2 mRNA with a moderate increase in MITF, tyrosinase and SILV gene mRNAs and complete repression of TYRP1 gene. Studies using inhibitors for protein kinases involved in cell signaling pathways suggested that stress-activated kinase p38 and mitogen-activated protein kinase kinase MEK are involved in TPA-independent regulation of TYRP2 expression in melanocytes. These data show that treatment of proliferating melanocytes with the differentiation inducer HMBA results in a distinct change in morphology and up-regulation of TYRP2, while quiescent melanocytes respond by a dramatic increase in expression of TYRP2 without change in morphology. These results suggest an inverse relationship of TYRP2 gene regulatory mechanisms to melanocyte growth regulatory pathways.
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Wang G, Yang X, Zhang Y, Wang Q, Chen H, Wei H, Xing G, Xie L, Hu Z, Zhang C, Fang D, Wu C, He F. Identification and characterization of receptor for mammalian hepatopoietin that is homologous to yeast ERV1. J Biol Chem 1999; 274:11469-72. [PMID: 10206950 DOI: 10.1074/jbc.274.17.11469] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hepatopoietin (HPO) is a novel polypeptide mitogen specific for hepatocytes and hepatoma cell lines, which is derived from liver and supports its regeneration. To determine whether HPO acts via a receptor-based signal transduction, recombinant human hepatopoietin was labeled by iodination and used to characterize its binding activity by specific displacement test and Scatchard analysis in primarily cultured rat hepatocytes and human hepatoma Hep-G2 cells. The binding was saturable and specific because it was replaceable by HPO but not by epidermal growth factor, transforming growth factor-alpha, or insulin. Scatchard analysis indicated the presence of a single class of high affinity receptor with dissociation constant (Kd) of 2 and 0.7 pM, and a receptor density of about 10, 000 sites/cell and 55,000 sites/cell in the rat hepatocytes and human hepatoma cells, respectively. The Kd values were consistent with the half-maximum dose of HPO activity. Affinity cross-linking of the receptor with 125I-HPO revealed a polypeptide of molecular mass approximately 90 kDa by SDS-polyacrylamide gel electrophoresis. Thus, the molecular mass of the HPO receptor was calculated to be about 75 kDa. These data demonstrated the existence of an HPO receptor in hepatocytes and hepatoma cells, which may account for biological effect.
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Ikejima K, Enomoto N, Iimuro Y, Ikejima A, Fang D, Xu J, Forman DT, Brenner DA, Thurman RG. Estrogen increases sensitivity of hepatic Kupffer cells to endotoxin. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:G669-76. [PMID: 9575848 DOI: 10.1152/ajpgi.1998.274.4.g669] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The relationship among gender, lipopolysaccharide (LPS), and liver disease is complex. Accordingly, the effect of estrogen on activation of Kupffer cells by endotoxin was studied. All rats given estrogen intraperitoneally 24 h before an injection of a sublethal dose of LPS (5 mg/kg) died within 24 h, whereas none of the control rats died. Mortality was prevented totally by pretreatment with gadolinium chloride, a Kupffer cell toxicant. Peak serum tumor necrosis factor-alpha (TNF-alpha) values as well as TNF-alpha mRNA in the liver after LPS were twice as high in the estrogen-treated group as in the untreated controls. Plasma nitrite levels and inducible nitric oxide synthase in the liver were also elevated significantly in estrogen-treated rats 6 h after LPS. Furthermore, Kupffer cells isolated from estrogen-treated rats produced about twice as much TNF-alpha and nitrite as controls did in response to LPS. In addition, Kupffer cells from estrogen-treated rats required 15-fold lower amounts of LPS to increase intracellular Ca2+ than controls did, and Kupffer cells from estrogen-treated animals expressed more CD14, the receptor for LPS/LPS binding protein, than controls. Moreover, estrogen treatment increased LPS binding protein mRNA dramatically in liver in 6-24 h. It is concluded that estrogen treatment in vivo sensitizes Kupffer cells to LPS, leading to increased toxic mediator production by the liver.
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Fang D, Hallman J, Sangha N, Kute TE, Hammarback JA, White WL, Setaluri V. Expression of microtubule-associated protein 2 in benign and malignant melanocytes: implications for differentiation and progression of cutaneous melanoma. THE AMERICAN JOURNAL OF PATHOLOGY 2001; 158:2107-15. [PMID: 11395388 PMCID: PMC1892002 DOI: 10.1016/s0002-9440(10)64682-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cutaneous melanocytic neoplasms are known to acquire variable characteristics of neural crest differentiation. Melanocytic nevus cells in the dermis and desmoplastic melanomas often display characteristics of nerve sheath differentiation. The extent and nature of neuronal differentiation characteristics displayed by primary and metastatic melanoma cells are not well understood. Here, we describe induction of a juvenile isoform of microtubule-associated protein 2 (MAP-2c) in cultured metastatic melanoma cells by the differentiation inducer hexamethylene bisacetamide. Up-regulation of this MAP-2 isoform, a marker for immature neurons, is accompanied by extended dendritic morphology and down-regulation of tyrosinase-related protein 1 (TYRP1/gp75), a melanocyte differentiation marker. In a panel of cell lines that represent melanoma tumor progression, MAP-2c mRNA and the corresponding approximately 70-kd protein could be detected predominantly in primary melanomas. Immunohistochemical analysis of 61 benign and malignant melanocytic lesions showed abundant expression of MAP-2 protein in melanocytic nevi and in the in situ and invasive components of primary melanoma, but only focal heterogeneous expression in a few metastatic melanomas. In contrast, MAP-2-positive dermal nevus cells and the invasive cells of primary melanomas were TYRP1-negative. This reciprocal staining pattern in vivo is similar to the in vitro observation that induction of the neuronal marker MAP-2 in metastatic melanoma cells is accompanied by selective extinction of the melanocytic marker TYRP1. Our data show that neoplastic melanocytes, particularly at early stages, retain the plasticity to express the neuron-specific marker MAP-2. These observations are consistent with the premise that both benign and malignant melanocytes in the dermis can express markers of neuronal differentiation.
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Li M, Lei H, Xu Y, Li H, Yang B, Yu C, Yuan Y, Fang D, Xin Z, Guan R. Exosomes derived from mesenchymal stem cells exert therapeutic effect in a rat model of cavernous nerves injury. Andrology 2018; 6:927-935. [PMID: 30009463 DOI: 10.1111/andr.12519] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 04/25/2018] [Accepted: 06/05/2018] [Indexed: 01/08/2023]
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Wang P, Yang Y, Hong H, Zhang Y, Cai W, Fang D. Aptamers as therapeutics in cardiovascular diseases. Curr Med Chem 2012; 18:4169-74. [PMID: 21848510 DOI: 10.2174/092986711797189673] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Revised: 05/26/2011] [Accepted: 05/28/2011] [Indexed: 12/18/2022]
Abstract
With many advantages over other therapeutic agents such as monoclonal antibodies, aptamers have recently emerged as a novel and powerful class of ligands with excellent potential for diagnostic and therapeutic applications. Typically generated through Systematic Evolution of Ligands by EXponential enrichment (SELEX), aptamers have been selected against a wide range of targets such as proteins, phospholipids, sugars, nucleic acids, as well as whole cells. DNA/RNA aptamers are single-stranded DNA/RNA oligonucleotides (with a molecular weight of 5-40 kDa) that can fold into well-defined 3D structures and bind to their target molecules with high affinity and specificity. A number of strategies have been adopted to synthesize aptamers with enhanced in vitro/in vivo stability, aiming at potential therapeutic/diagnostic applications in the clinic. In cardiovascular diseases, aptamers can be developed into therapeutic agents as anti-thrombotics, anti-coagulants, among others. This review focuses on aptamers that were selected against various molecular targets involved in cardiovascular diseases: von Willebrand factor (vWF), thrombin, factor IX, phospholamban, P-selectin, platelet-derived growth factor, integrin α(v)β(3), CXCL10, vasopressin, among others. With continued effort in the development of aptamer-based therapeutics, aptamers will find their niches in cardiovascular diseases and significantly impact clinical patient management.
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Fang D, Zhang D, Huang G, Zhang R, Wang L, Zhang D. Results of surgical resection of patients with primary lung cancer: a retrospective analysis of 1,905 cases. Ann Thorac Surg 2001; 72:1155-9. [PMID: 11603429 DOI: 10.1016/s0003-4975(01)02932-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Surgical resection, combined therapies, and lymphadenectomy are extensively utilized in the treatment of patients with lung cancer. In the present study, we summarized the clinical data of patients with primary lung cancer after surgical resection alone or combined with adjuvant therapy, and evaluate the main factors influencing long-term survival. METHODS A retrospective review of 1,905 consecutive patients with primary lung cancer treated at the Cancer Institute of the Chinese Academy of Medical Sciences from March 1961 through December 1995 was performed. Statistical analysis was done using STATA software. The survival rate was estimated using the life-table method. Survival differences were performed using the log-rank test. The modified 1997 TNM staging system was used. RESULTS There was a 12.28% morbidity rate and a 1.31% hospital mortality in our series. The 5-year survival rate for the complete resection was 49.5% and for the palliative resection 18.8% (p < 0.01). The 5-year survival rate was 72.0% in stage IA and 61.0% in stage IB (p < 0.05), 32.9% in stage IIA and 34.5% in stage IIB, 22.6% in stage IIIA and 15.9% in stage IIIB (p < 0.05), and 7.1% in stage IV. CONCLUSIONS Multiple factors influence the long-term survival of patients with primary lung cancer after surgery. They include TNM staging, the extent of surgical resection (complete or palliative), resection margin (positive or negative), pathologic type of tumors, and type of resection.
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Fang D, Seisen T, Yang K, Liu P, Fan X, Singla N, Xiong G, Zhang L, Li X, Zhou L. A systematic review and meta-analysis of oncological and renal function outcomes obtained after segmental ureterectomy versus radical nephroureterectomy for upper tract urothelial carcinoma. Eur J Surg Oncol 2016; 42:1625-1635. [PMID: 27612412 DOI: 10.1016/j.ejso.2016.08.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/03/2016] [Accepted: 08/06/2016] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVE To perform a systematic review and meta-analysis of the comparative studies reporting oncological and renal function outcomes of segmental ureterectomy (SU) versus radical nephroureterectomy (RNU) for upper tract urothelial carcinomas (UTUC). MATERIALS AND METHODS A literature search on Pubmed, Embase, and the Cochrane library was conducted according to the PRISMA guidelines, and a meta-analysis was performed to assess cancer-specific survival (CSS), overall survival (OS), recurrence-free survival (RFS), intravesical recurrence free survival (IVRFS) and surgery-related variations in estimated glomerular filtration rate (eGFR). RESULTS A total of 11 retrospective studies with 3963 patients who underwent either SU (n = 983; 24.8%) or RNU (n = 2980; 75.2%) were included. Although patients treated with SU were more likely to be diagnosed with favorable pathological features, the meta-analysis of unadjusted data revealed no significant difference between both groups in terms of CSS (HR 0.90, p = 0.33) and OS (HR 0.98, p = 0.93). Accordingly, the meta-analysis of adjusted data confirmed equivalent CSS (HR = 0.90, p = 0.47) between SU and RNU. Similarly, no significant difference was found in terms of RFS (HR 1.06, p = 0.72) and IVRFS (HR 1.35, p = 0.39). However, a significant decreased risk of impaired renal function was observed after SU when compared to RNU (mean eGFR difference = 9.32 ml/1.73 m2, p = 0.007). CONCLUSION Although adverse patient and tumor characteristics were not equally balanced between treatment arms, our systematic review and meta-analysis supports similar oncological outcomes between SU and RNU, with better preservation of renal function after SU. As such, SU should be preferably used as the first-line treatment for low-risk ureter tumors, while considered for selected cases of high-risk disease.
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Fang D, Kurebayashi H, Wunderlich J, Výborný K, Zârbo LP, Campion RP, Casiraghi A, Gallagher BL, Jungwirth T, Ferguson AJ. Spin-orbit-driven ferromagnetic resonance. NATURE NANOTECHNOLOGY 2011; 6:413-417. [PMID: 21602814 DOI: 10.1038/nnano.2011.68] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 04/07/2011] [Indexed: 05/30/2023]
Abstract
Ferromagnetic resonance is the most widely used technique for characterizing ferromagnetic materials. However, its use is generally restricted to wafer-scale samples or specific micro-magnetic devices, such as spin valves, which have a spatially varying magnetization profile and where ferromagnetic resonance can be induced by an alternating current owing to angular momentum transfer. Here we introduce a form of ferromagnetic resonance in which an electric current oscillating at microwave frequencies is used to create an effective magnetic field in the magnetic material being probed, which makes it possible to characterize individual nanoscale samples with uniform magnetization profiles. The technique takes advantage of the microscopic non-collinearity of individual electron spins arising from spin-orbit coupling and bulk or structural inversion asymmetry in the band structure of the sample. We characterize lithographically patterned (Ga,Mn)As and (Ga,Mn)(As,P) nanoscale bars, including broadband measurements of resonant damping as a function of frequency, and measurements of anisotropy as a function of bar width and strain. In addition, vector magnetometry on the driving fields reveals contributions with the symmetry of both the Dresselhaus and Rashba spin-orbit interactions.
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