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Dou L, Wong AB, Yu Y, Lai M, Kornienko N, Eaton SW, Fu A, Bischak CG, Ma J, Ding T, Ginsberg NS, Wang LW, Alivisatos AP, Yang P. Atomically thin two-dimensional organic-inorganic hybrid perovskites. Science 2015; 349:1518-21. [DOI: 10.1126/science.aac7660] [Citation(s) in RCA: 991] [Impact Index Per Article: 99.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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10 |
991 |
2
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Chan ATC, Teo PML, Ngan RK, Leung TW, Lau WH, Zee B, Leung SF, Cheung FY, Yeo W, Yiu HH, Yu KH, Chiu KW, Chan DT, Mok T, Yuen KT, Mo F, Lai M, Kwan WH, Choi P, Johnson PJ. Concurrent chemotherapy-radiotherapy compared with radiotherapy alone in locoregionally advanced nasopharyngeal carcinoma: progression-free survival analysis of a phase III randomized trial. J Clin Oncol 2002; 20:2038-2044. [PMID: 11956263 DOI: 10.1200/jco.2002.08.149] [Citation(s) in RCA: 368] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
PURPOSE Nasopharyngeal carcinoma (NPC) is highly sensitive to both radiotherapy (RT) and chemotherapy. This randomized phase III trial compared concurrent cisplatin-RT (CRT) with RT alone in patients with locoregionally advanced NPC. PATIENTS AND METHODS Patients with Ho's N2 or N3 stage or N1 stage with nodal size > or = 4 cm were randomized to receive cisplatin 40 mg/m(2) weekly up to 8 weeks concurrently with radical RT (CRT) or RT alone. The primary end point was progression-free survival (PFS). RESULTS Three hundred fifty eligible patients were randomized. Baseline patient characteristics were comparable in both arms. There were significantly more toxicities, including mucositis, myelosuppression, and weight loss in the CRT arm. There were no treatment-related deaths in the CRT arm, and one patient died during treatment in the RT-alone arm. At a median follow-up of 2.71 years, the 2-year PFS was 76% in the CRT arm and 69% in the RT-alone arm (P =.10) with a hazards ratio of 1.367 (95% confidence interval [CI], 0.93 to 2.00). The treatment effect had a significant covariate interaction with tumor stage, and a subgroup analysis demonstrated a highly significant difference in favor of the CRT arm in Ho's stage T3 (P =.0075) with a hazards ratio of 2.328 (95% CI, 1.26 to 4.28). For T3 stage, the time to first distant failure was statistically significantly different in favor of the CRT arm (P =.016). CONCLUSION Concurrent CRT is well tolerated in patients with advanced NPC in endemic areas. Although PFS was not significantly different between the concurrent CRT arm and the RT-alone arm in the overall comparison, PFS was significantly prolonged in patients with advanced tumor and node stages.
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Clinical Trial |
23 |
368 |
3
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Zhang H, Li Y, Huang Q, Ren X, Hu H, Sheng H, Lai M. MiR-148a promotes apoptosis by targeting Bcl-2 in colorectal cancer. Cell Death Differ 2011; 18:1702-10. [PMID: 21455217 DOI: 10.1038/cdd.2011.28] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Apoptosis has a vital role in maintaining tissue homeostasis, and dysregulation of the apoptotic pathway is now widely recognized as a key step in tumourigenesis. Increasingly, evidence has demonstrated that microRNA (miRNA) can exert various biological functions in tumours by targeting oncogenes or tumour suppressors. Nevertheless, the role of miRNA in apoptosis remains unclear. Here we show that ectopical expression of miR-148a can induce apoptosis in colorectal cancer cells. In addition, MYB can inhibit miR-148a by directly acting on the transcription factor binding site in miR-148a gene and miR-148a can posttranscriptionally silence Bcl-2. Subsequently, the intrinsic apoptosis pathway is activated by releasing cytochrome c, cleaving caspase 9, caspase 3 and PARP, which eventually induce cancer-cell apoptosis. These findings are part of a hitherto undocumented apoptotic regulatory pathway in which a pleiotropic transcription factor controls the expression of a miRNA and the miRNA inhibits the target, leading to activation of an intrinsic mitochondrial pathway and tumour apoptosis.
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Research Support, Non-U.S. Gov't |
14 |
172 |
4
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van Oosten BW, Lai M, Hodgkinson S, Barkhof F, Miller DH, Moseley IF, Thompson AJ, Rudge P, McDougall A, McLeod JG, Adèr HJ, Polman CH. Treatment of multiple sclerosis with the monoclonal anti-CD4 antibody cM-T412: results of a randomized, double-blind, placebo-controlled, MR-monitored phase II trial. Neurology 1997; 49:351-7. [PMID: 9270561 DOI: 10.1212/wnl.49.2.351] [Citation(s) in RCA: 166] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We report the results of a randomized, double-blind, placebo-controlled exploratory trial of the chimeric monoclonal anti-CD4 antibody cM-T412 in 71 patients suffering from active relapsing-remitting and secondary progressive multiple sclerosis. Infusion of the antibody produced frequent but usually minor side effects and resulted in a long-lasting reduction of circulating CD4-positive T cells. There was no significant effect on the primary measure of efficacy, the number of active lesions on monthly gadolinium-enhanced MRI over 9 months. Further statistical evaluation provided evidence that the degree of depletion of CD4-positive cells was important with regard to treatment efficacy; using CD4 counts as a covariate there was a statistically significant effect on the number of active lesions over 18 months (p = 0.04). There was a statistically significant reduction of 41% in the number of clinical relapses (a secondary efficacy parameter) after 9 months (p = 0.02), which was still present after 18 months, but this finding may be partly due to physician unblinding. Other secondary efficacy parameters (Expanded Disability Status Scale progression, number of courses of methylprednisolone) were not influenced by anti-CD4 treatment. We conclude that intravenous treatment with the monoclonal antibody cM-T412 in the dosage we used results in a substantial and sustained reduction of the number of circulating CD4-positive cells, but is not able to reduce MS activity as measured by monthly gadolinium-enhanced MRI, and is therefore unlikely to have a beneficial effect on the clinical disease course. We found preliminary evidence suggesting that more aggressive depletion of CD4-positive cells might lead to a more substantial reduction in MRI activity.
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Clinical Trial |
28 |
166 |
5
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Graus F, Saiz A, Lai M, Bruna J, López F, Sabater L, Blanco Y, Rey MJ, Ribalta T, Dalmau J. Neuronal surface antigen antibodies in limbic encephalitis: clinical-immunologic associations. Neurology 2008; 71:930-6. [PMID: 18794496 DOI: 10.1212/01.wnl.0000325917.48466.55] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To report the frequency and type of antibodies against neuronal surface antigens (NSA-ab) in limbic encephalitis (LE). METHODS Analysis of clinical features, neuropathologic findings, and detection of NSA-ab using immunochemistry on rat tissue and neuronal cultures in a series of 45 patients with paraneoplastic (23) or idiopathic (22) LE. RESULTS NSA-ab were identified in 29 patients (64%; 12 paraneoplastic, 17 idiopathic). Thirteen patients had voltage-gated potassium channels (VGKC)-ab, 11 novel NSA (nNSA)-ab, and 5 NMDA receptor (NMDAR)-ab. nNSA-ab did not identify a common antigen and were more frequent in paraneoplastic than idiopathic LE (39% vs 9%; p = 0.03). When compared with VGKC-ab or NMDAR-ab, the nNSA associated more frequently with intraneuronal antibodies (11% vs 73%; p = 0.001). Of 12 patients (9 nNSA-ab, 2 VGKC-ab, 1 NMDAR-ab) with paraneoplastic LE and NSA-ab, concomitant intraneuronal antibodies occurred in 9 (75%). None of these 12 patients improved with immunotherapy. The autopsy of three of them showed neuronal loss, microgliosis, and cytotoxic T cell infiltrates in the hippocampus and amygdala. These findings were compatible with a T-cell mediated neuronal damage. In contrast, 13 of 17 (76%) patients with idiopathic LE and NSA-ab (8 VGKC-ab, 4 NMDAR-ab, 1 nNSA-ab) and 1 of 5 (20%) without antibodies had clinical improvement (p = 0.04). CONCLUSIONS In paraneoplastic limbic encephalitis (LE), novel antibodies against neuronal surface antigens (nNSA-ab) occur frequently, coexist with antibodies against intracellular antigens, and these cases are refractory to immunotherapy. In idiopathic LE, the likelihood of improvement is significantly higher in patients with NSA-ab than in those without antibodies.
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Research Support, Non-U.S. Gov't |
17 |
150 |
6
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Grimaud J, Lai M, Thorpe J, Adeleine P, Wang L, Barker GJ, Plummer DL, Tofts PS, McDonald WI, Miller DH. Quantification of MRI lesion load in multiple sclerosis: a comparison of three computer-assisted techniques. Magn Reson Imaging 1996; 14:495-505. [PMID: 8843362 DOI: 10.1016/0730-725x(96)00018-5] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Several computer-assisted techniques for measuring multiple sclerosis lesion load on MR images have been developed to provide a quantitative and sensitive means for monitoring disease activity, particularly in the context of treatment trials. We have evaluated three techniques: manual outlining (similar to that of the North American interferon beta-1b trial), semiautomated lesion contouring (local lesion based threshold), and intensity-based thresholding for the whole brain. Contiguous, 5 mm-thick, axial, T2-weighted images of the brain were obtained on a 1.5T MR imager in eight patients with clinically definite multiple sclerosis. Analyses of the scans were performed twice, independently by three operators, using the three different techniques. The coefficient of variation of the measurement techniques was: (a) intrarater precision, 9.0 +/- 5.2 (mean +/- SD) (range 0.4-18.5) for the manual outlining, 2.5 +/- 2.1 (0.1-7.7) for the contour technique, and 7.5 +/- 6.9 (0.2-22.0) for the global threshold technique; (b) interrater precision, 11.0 +/- 5.8 (4.9-21.7) for the manual outlining, 4.5 +/- 1.6 (1.8-6.6) for the contour technique, and 11.4 +/- 4.9 (2.8-19.2) for the global threshold technique (0.0 = perfect precision). The absolute lesion loads measured were very similar using the manual outlining and the contour techniques but were significantly smaller using the global threshold technique. We conclude that the contour technique is a promising tool for use in treatment trials. Further studies are needed to assess sensitivity to changes in lesion load over time.
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Comparative Study |
29 |
133 |
7
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Horsfield MA, Lai M, Webb SL, Barker GJ, Tofts PS, Turner R, Rudge P, Miller DH. Apparent diffusion coefficients in benign and secondary progressive multiple sclerosis by nuclear magnetic resonance. Magn Reson Med 1996; 36:393-400. [PMID: 8875409 DOI: 10.1002/mrm.1910360310] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The diffusion characteristics of water in brain white matter were studied in patients with benign and secondary progressive multiple sclerosis (MS), and also in normal controls. In the MS patients, both lesions and normal-appearing white matter (NAWM) were examined to assess whether pathological differences might be evident from the diffusion behavior. A volume-selective technique was used to reduce data acquisition time and improve the reliability and precision of the measurements. This also allowed the time-dependence of apparent diffusion coefficients to be assessed. While lesions from both patient groups showed an elevated diffusion coefficient, no differences between the two groups were found. In addition, NAWM was elevated for both patient groups compared with the control group, although this was only statistically significant for patients with a benign disease course. The degree of elevation of the diffusion coefficient within the individual lesions measured was not related to the disability of the patient. Pathological differences between lesions in patients with different disease courses, if they exist, have not been detected in this study of brain water diffusion.
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29 |
125 |
8
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Felisari G, Martinelli Boneschi F, Bardoni A, Sironi M, Comi GP, Robotti M, Turconi AC, Lai M, Corrao G, Bresolin N. Loss of Dp140 dystrophin isoform and intellectual impairment in Duchenne dystrophy. Neurology 2000; 55:559-64. [PMID: 10953192 DOI: 10.1212/wnl.55.4.559] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Mental retardation is a clinical feature of Duchenne dystrophy (DD) and affects about one-third of patients. No clear association has been found between DNA mutations, protein expression, and IQ scores, although distal deletions in the dystrophin gene have been reported in association with intellectual impairment. A role for the brain distal dystrophin isoform Dp140 was suggested. OBJECTIVE To explore the possible association between cognitive impairment and DNA macrodeletions in the distal part of the gene, including Dp140 gene region. METHODS Sixty-six patients with DD received general intelligence assessment by Wechsler Intelligence Scales measuring full, verbal, and performance IQ. PCR analysis was performed to detect deletions in the dystrophin gene, and the Dp140 regulatory region was analyzed in a subgroup of 12 patients. Statistical analysis was performed by nonparametric Wilcoxon rank signed and rank sum tests. RESULTS Comparison of neuropsychological and genetic data revealed an association between distal macrodeletions and cognitive impairment (p < 0.001). Comparing deletions involving the Dp140 gene region with deletions presumably not altering Dp140 expression resulted in even greater significance. CONCLUSIONS These data suggest that in DD, distal dystrophin deletions are associated with intellectual impairment. This study highlights a possible role for the brain distal isoform Dp140 in normal cognitive development.
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Comparative Study |
25 |
97 |
9
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MacLennan AJ, Brecha N, Khrestchatisky M, Sternini C, Tillakaratne NJ, Chiang MY, Anderson K, Lai M, Tobin AJ. Independent cellular and ontogenetic expression of mRNAs encoding three alpha polypeptides of the rat GABAA receptor. Neuroscience 1991; 43:369-80. [PMID: 1656319 DOI: 10.1016/0306-4522(91)90301-4] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Previous studies have shown that several distinct but related polypeptides can serve as alpha subunits of functional GABAA receptors. Furthermore, the diversity of these polypeptides at least partially accounts for the functional heterogeneity of GABAA receptors. In this paper, we report the results of in situ hybridization studies using probes derived from our recently reported cDNAs for alpha 1, alpha 2, and alpha 4 GABAA receptor polypeptides. We show that the mRNAs that encode these isoforms have distinct regional and cellular distributions and are present at widely varying levels within the rat brain. In addition, our Northern blot analyses indicate that each of these three alpha mRNAs has a distinct pattern of ontogenetic regulation. Differential regulation of alpha polypeptide isoforms may lead to changes in GABAA receptor function during ontogeny as well as to distinct cellular responses to GABA and GABA-related drugs.
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34 |
94 |
10
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Wu DD, Lai M, Hughes PE, Sirimanne E, Gluckman PD, Williams CE. Expression of the activin axis and neuronal rescue effects of recombinant activin A following hypoxic-ischemic brain injury in the infant rat. Brain Res 1999; 835:369-78. [PMID: 10415398 DOI: 10.1016/s0006-8993(99)01638-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Neurotrophic factors are induced in the brain in response to injury and may restrict the extent of neuronal loss and facilitate recovery. We have previously reported a strong neuronal induction of activin betaA subunit mRNA expression after a hypoxic-ischemic (HI) injury in the rat brain. Here, we further extended our studies to examine a role for the activin inhibitory binding protein, follistatin after injury and also to determine the potential of activin as a neuronal rescue agent. Ribonuclease protection assay (RPA) was used to quantify the time course of the mRNA expression of activin betaA subunit and follistatin, following a 60-min HI brain injury. Activin betaA subunit mRNA level increased in the contralateral hemisphere 5 h after injury and returned to normal at 10 h post injury. In contrast, follistatin mRNA levels decreased in the same hemisphere at 5 and 10 h after injury. The effect of intracerebroventrically (i. c.v.) administered recombinant human activin A or its antagonist, inhibin A, on neuronal death after a 15-min HI brain injury was determined for a number of brain regions. One microgram activin A (n=23) reduced the neuronal loss in the hippocampal CA1/2 region, dorsolateral striatum but not in the parietal cortex. In contrast, 1 microg of inhibin A (n=18) did not have a significant effect on the extent of neuronal loss in any of the affected regions. This pattern of neuroprotection was consistent with the distribution of immunoreactivity for the activin receptor type II subunit. These results demonstrate that activin A, but not its functional antagonist inhibin A, can enhance the survival of injured hippocampal and striatal neurons. Since follistatin is thought to exert a neutralising effect on activin A activity, the down-regulation of follistatin expression post injury may be allowing activin A to become more accessible to neurons after injury. Overall, these results suggest a role of the activin axis in modulating the survival of specific populations of injured neurons.
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83 |
11
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Lai M, Chandrasekera PC, Barnard ND. You are what you eat, or are you? The challenges of translating high-fat-fed rodents to human obesity and diabetes. Nutr Diabetes 2014; 4:e135. [PMID: 25198237 PMCID: PMC4183971 DOI: 10.1038/nutd.2014.30] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 06/18/2014] [Accepted: 06/25/2014] [Indexed: 12/16/2022] Open
Abstract
Obesity and type 2 diabetes mellitus (T2DM) are rapidly growing worldwide epidemics with major health consequences. Various human-based studies have confirmed that both genetic and environmental factors (particularly high-caloric diets and sedentary lifestyle) greatly contribute to human T2DM. Interactions between obesity, insulin resistance and β-cell dysfunction result in human T2DM, but the mechanisms regulating the interplay among these impairments remain unclear. Rodent models of high-fat diet (HFD)-induced obesity have been used widely to study human obesity and T2DM. With >9000 publications on PubMed over the past decade alone, many aspects of rodent T2DM have been elucidated; however, correlation to human obesity/diabetes remains poor. This review investigates the reasons for this translational discrepancy by critically evaluating rodent HFD models. Dietary modification in rodents appears to have limited translatable benefit for understanding and treating human obesity and diabetes due—at least in part—to divergent dietary compositions, species/strain and gender variability, inconsistent disease penetrance, severity and duration and lack of resemblance to human obesogenic pathophysiology. Therefore future research efforts dedicated to acquiring translationally relevant data—specifically human data, rather than findings based on rodent studies—would accelerate our understanding of disease mechanisms and development of therapeutics for human obesity/T2DM.
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Review |
11 |
82 |
12
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Silver NC, Lai M, Symms MR, Barker GJ, McDonald WI, Miller DH. Serial magnetization transfer imaging to characterize the early evolution of new MS lesions. Neurology 1998; 51:758-64. [PMID: 9748023 DOI: 10.1212/wnl.51.3.758] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To explore the temporal relation of demyelination and blood-brain barrier breakdown during new lesion formation. BACKGROUND Conventional MRI appears sensitive for detecting changes due to MS, but may be limited by poor pathologic specificity. By indirectly assessing protons bound to rigid macromolecules, magnetization transfer (MT) imaging may provide information relating to tissue structure and, by inference, myelin integrity. METHODS Gadolinium contrast-enhanced MRI and MT imaging were performed at weekly intervals for 3 months in three patients with MS. For each enhancing lesion, the largest corresponding area of proton density hyperintensity seen during the study was outlined and magnetization transfer ratio (MTR) calculated at each time point from coregistered calculated MTR images. Lesions greater than 20 mm2, not affected by partial volume effects, and first enhancing after the baseline study were analyzed. Two-dimensional registration software allowed accurate evaluation of MTR in regions both before and after the initial appearance of MS lesions. RESULTS Mean lesion MTR decreased significantly during the first week of enhancement (29.6 percent units [pu] immediately pre-enhancement versus 28.2 pu at first documented stage of enhancement). No significant MTR reduction was noted before this. CONCLUSION The lack of observable change in MTR before the first detectable gadolinium enhancement within MS lesions suggests that blood-brain barrier disruption is closely related to, but not preceded by, demyelination.
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27 |
77 |
13
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Coraddu F, Sawcer S, D'Alfonso S, Lai M, Hensiek A, Solla E, Broadley S, Mancosu C, Pugliatti M, Marrosu MG, Compston A. A genome screen for multiple sclerosis in Sardinian multiplex families. Eur J Hum Genet 2001; 9:621-6. [PMID: 11528508 DOI: 10.1038/sj.ejhg.5200680] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2000] [Revised: 04/18/2001] [Accepted: 05/09/2001] [Indexed: 11/09/2022] Open
Abstract
The prevalence of multiple sclerosis in Sardinia is significantly higher than in neighbouring Mediterranean countries, suggesting that the isolated growth of the population has concentrated genetic factors which increase susceptibility to the disease. The distinct HLA association of multiple sclerosis in Sardinia supports this interpretation. We have performed a whole genome screen for linkage in 49 Sardinian multiplex families using 327 markers. Non parametric linkage analysis of these data reveal suggestive linkage in the region of Chr 1q31, Chr 10q23 and Chr 11p15.
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24 |
77 |
14
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Corongiu FP, Lai M, Milia A. Carbon tetrachloride, bromotrichloromethane and ethanol acute intoxication. New chemical evidence for lipid peroxidation in rat tissue microsomes. Biochem J 1983; 212:625-31. [PMID: 6882388 PMCID: PMC1153136 DOI: 10.1042/bj2120625] [Citation(s) in RCA: 77] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Second-derivative spectroscopy was used to determine the conjugated-diene shift that measures the extent of the first step of lipid peroxidation after carbon tetrachloride (CCl4), bromotrichloromethane (BrCCl3) and ethanol intoxication. The conjugated-diene signal was recorded in the second-derivative spectra as a minimum peak at 233 nm. The use of this method enabled us to show that, under our experimental conditions, CCl4- and BrCCl3-dependent conjugated-diene formation in rat liver microsomes is not dose-dependent and increases linearly with time up to 3h. Proportionality was not obtained between the second-derivative-spectroscopy method, and the thiobarbituric acid and difference-spectra methods. In addition, whereas the thiobarbituric acid and difference-spectra methods gave positive results at zero time, second-derivative spectroscopy showed no evidence of formation of conjugated dienes under the same experimental conditions. Intoxication with ethanol was shown by the appearance of the conjugated-diene signal in liver microsomes 24 h after the administration of the toxin. Intoxication with either of the haloalkanes or ethanol did not give rise to any similar peak in lung and brain microsomes. The results obtained are discussed.
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research-article |
42 |
77 |
15
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Zhou W, Liu H, Zhang F, Tang S, Zhu H, Lai M, Kalivas PW. Role of acetylcholine transmission in nucleus accumbens and ventral tegmental area in heroin-seeking induced by conditioned cues. Neuroscience 2006; 144:1209-18. [PMID: 17184925 PMCID: PMC1868450 DOI: 10.1016/j.neuroscience.2006.11.013] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 11/06/2006] [Accepted: 11/08/2006] [Indexed: 01/21/2023]
Abstract
The involvement of cholinergic transmission in heroin self-administration and the reinstatement of heroin-seeking was examined in rats trained to nose-poke for i.v. heroin. Systemic treatment with physostigmine, an inhibitor of acetylcholinesterase, modestly reduced the acquisition and rate of heroin self-administration, and this suppression of heroin intake was reversed by pretreatment with scopolamine but not by mecamylamine. Following 10-14 days of self-administration, rats were left in the home environment for 14 days. Subsequently, rats were evaluated for extinction of nose-pokes during the first hour after being returned to the self-administration apparatus. One hour later a conditioned stimulus (house light, light in the nose-poke hole, sound of the infusion pump) was presented to initiate cue-induced reinstatement. Physostigmine produced a dose-dependent inhibition of cue-induced reinstatement, but only the dose of 0.5 mg/kg significantly decreased nose-poke responding in the extinction test. Chronic treatment with physostigmine (0.1 mg/kg) did not impair performance during acquisition of heroin self-administration. However, during a subsequent reinstatement test conducted in the absence of physostigmine pretreatment, heroin seeking was significantly below that of rats chronically pretreated with saline. To evaluate brain regions mediating the effects of systemic drug treatment on reinstatement, physostigmine was microinjected into the nucleus accumbens (NAc) or ventral tegmental area (VTA). Microinjection of physostigmine into the NAc prior to presenting conditioned cues inhibited the reinstatement of heroin-seeking, without affecting extinction responding. In contrast, microinjection of physostigmine into the VTA augmented the reinstatement induced by conditioned cues and extinction responding. Inactivation of either NAc or VTA by microinjecting tetrodotoxin blocked both extinction responding and cue-induced reinstatement. These data demonstrate that cholinergic transmission influences heroin self-administration and reinstatement. Moreover, cue-induced reinstatement was inhibited by physostigmine in the NAc and potentiated by cholinergic stimulation in the VTA.
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Research Support, Non-U.S. Gov't |
19 |
74 |
16
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Rodgers M, Epstein D, Bojke L, Yang H, Craig D, Fonseca T, Myers L, Bruce I, Chalmers R, Bujkiewicz S, Lai M, Cooper N, Abrams K, Spiegelhalter D, Sutton A, Sculpher M, Woolacott N. Etanercept, infliximab and adalimumab for the treatment of psoriatic arthritis: a systematic review and economic evaluation. Health Technol Assess 2011; 15:i-xxi, 1-329. [PMID: 21333232 DOI: 10.3310/hta15100] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Etanercept, infliximab and adalimumab are licensed in the UK for the treatment of active and progressive psoriatic arthritis (PsA) in adults who have an inadequate response to standard treatment. OBJECTIVE To determine the clinical effectiveness, safety and cost-effectiveness of these biologic agents in the treatment of active and progressive PsA. DATA SOURCES Systematic reviews were performed, with data sought from 10 electronic databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Science Citation Index, Conference Proceedings Citation Index - Science, ClinicalTrials.gov, metaRegister of Current Controlled Trials, NHS Economic Evaluation Database, Health Economic Evaluations Database and EconLit) up to June 2009. REVIEW METHODS Full paper manuscripts of titles/abstracts considered relevant were obtained and assessed for inclusion by two reviewers according to criteria on study design, interventions, participants and outcomes. Data on study and participant characteristics, efficacy outcomes, adverse effects, costs to the health service and cost-effectiveness were extracted, along with baseline data where reported. The primary efficacy outcomes were measures of anti-inflammatory response, skin lesion response and functional status, and the safety outcome was the incidence of serious adverse events. The primary measure of cost-effectiveness was incremental cost per additional quality-adjusted life-year (QALY). Standard meta-analytic techniques were applied to efficacy data. Published cost-effectiveness studies and the economic analyses submitted to the National Institute for Health and Clinical Excellence (NICE) by the biologic manufacturers were reviewed. An economic model was developed by updating the model produced by the York Assessment Group for the previous NICE appraisal of biologics in PsA. RESULTS Pooled estimates of effect demonstrated a significant improvement in patients with PsA for all joint disease and functional status outcomes at 12-14 weeks' follow-up. The biologic treatment significantly reduced joint symptoms for etanercept [relative risk (RR) 2.60, 95% confidence interval (CI) 1.96 to 3.45], infliximab (RR 3.44, 95% CI 2.53 to 4.69) and adalimumab (RR 2.24, 95% CI 1.74 to 2.88), with 24-week data demonstrating maintained treatment effects. Trial data demonstrated a significant effect of all three biologics on skin disease at 12 or 24 weeks. Evidence synthesis found that infliximab appeared to be most effective across all outcomes of joint and skin disease. The response in joint disease was greater with etanercept than with adalimumab, whereas the response in skin disease was greater with adalimumab than with etanercept, although these differences are not statistically significant. Under base-case assumptions, etanercept was the most likely cost-effective strategy for patients with PsA and mild-to-moderate psoriasis if the threshold for cost-effectiveness was £20,000 or £30,000 per QALY. All biologics had a similar probability of being cost-effective for patients with PsA and moderate-to-severe psoriasis at a threshold of £20,000 per QALY. LIMITATIONS Limited available efficacy data and difficulty in assessing PsA activity and its response to biologic therapy. CONCLUSIONS The data indicated that etanercept, infliximab and adalimumab were efficacious in the treatment of PsA compared with placebo, with beneficial effects on joint symptoms, functional status and skin. Short-term data suggested that these biologic agents can delay joint disease progression and evidence to support their use in the treatment of PsA is convincing. Future research would benefit from long-term observational studies with large sample sizes of patients with PsA to demonstrate that beneficial effects are maintained, along with further monitoring of the safety profiles of the biologic agents. FUNDING The National Institute for Health Research Health Technology Assessment programme.
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Systematic Review |
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Baldessarini RJ, Bolzani L, Cruz N, Jones PB, Lai M, Lepri B, Perez J, Salvatore P, Tohen M, Tondo L, Vieta E. Onset-age of bipolar disorders at six international sites. J Affect Disord 2010; 121:143-6. [PMID: 19560827 DOI: 10.1016/j.jad.2009.05.030] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 05/27/2009] [Accepted: 05/28/2009] [Indexed: 11/25/2022]
Abstract
BACKGROUND Onset-age is a stable characteristic of bipolar disorder (BPD) patients of clinical and probable psychobiological importance, but large pooled clinical samples from multiple sites employing modern diagnostic criteria to quantify onset-age remain rare. METHODS We pooled diagnostic, demographic, and clinical data from 1566 BPD patients from six international sites (5 European, 1 US) to compare onset-ages in subgroups. RESULTS Median+/-IQR onset in 1090 BP-I patients was 5.8 years younger than 476 BP-II cases (24.3+/-18.3 vs. 30.1+/-13.8 years; p<0.0001). Onset-age ranked: [a] BP-I men (23.0+/-12.8); [b] BP-I women (26.0+/-14.2); [c] BP-II men (29.7+/-19.1); and [d] BP-II women (30.1+/-17.5 years. Juvenile-onset (<or=age 20) was more common in Europe than the US (27% vs. 16%), as was childhood-onset (<13 years: 3.3% vs. 0%; both p<0.001). Proportion of all cases, and median onset for first episodes ranked: [a] BP-I psychotic (6.3%; 22.7+/-9.2); [b] BP-I manic (29.3%; 24.0+/-12.1); [c] BP-I depressed (25.1%; 24.5+/-14.9); [d] BP-I mixed (9.7%; 27.9+/-16.0); [e] BP-II depressed (26.9%; 30.0+/-19.5); and [f] BP-II hypomanic (2.8%; 33.6+/-15.1 years; p<0.0001). Among BP-I patients, onset was similar for various forms of mania and major depression; in BP-II patients initial depression was 9.6-times more frequent and diagnosed earlier than hypomania. LIMITATIONS There was some variance among sites and only 34.1% of patients were evaluated at onset. CONCLUSIONS Type I BPD began much earlier than type II; its mainly psychotic presentations occurred earliest, but BP-I men were younger than women, especially at psychotic or mixed onsets.
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Usai P, Usai Satta P, Lai M, Corda MG, Piras E, Calcara C, Boy MF, Morelli A, Balestrieri A, Bassotti G. Autonomic dysfunction and upper digestive functional disorders in untreated adult coeliac disease. Eur J Clin Invest 1997; 27:1009-1015. [PMID: 9466129 DOI: 10.1046/j.1365-2362.1997.2340781.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
There is recent evidence that upper-gut motor abnormalities may be present in coeliac disease. However, to date, the pathophysiological mechanisms responsible for the above have not been explored. The purpose of the present study was to investigate upper-gut motor activity in coeliac disease and explore the role played by the autonomic nervous system in motility disturbances. Thirty untreated adult coeliac patients were recruited into the study. Oesophageal manometry and cardiovascular autonomic tests were performed in all patients; oesophageal pH-metry was carried out in 20 patients, gastrointestinal manometry in eight and scintigraphic gastric emptying in 13. Oesophageal motor abnormalities were detected in about 50% of patients, pH-metry was abnormal in 30% of them, and up to 75% of coeliac patients displayed gastrointestinal motility alterations. Delayed gastric emptying was documented in about 50% of patients and was correlated with manometric post-prandial hypomotility. Autonomic tests were positive in 45% of patients as a group, and reached pathological score in 19% of them. Autonomic score correlated significantly with the percentage of bi-peaked waves and with the number of fasting intestinal clusters. This study confirms that upper-gut motor abnormalities are frequently present in adult coeliac disease. Extrinsec autonomic neuropathy may play a role, although other pathophysiological mechanisms are likely to occur.
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Chien UH, Lai M, Shih TY, Verma IM, Scolnick EM, Roy-Burman P, Davidson N. Heteroduplex analysis of the sequence relationships between the genomes of Kirsten and Harvey sarcoma viruses, their respective parental murine leukemia viruses, and the rat endogenous 30S RNA. J Virol 1979; 31:752-60. [PMID: 229250 PMCID: PMC353503 DOI: 10.1128/jvi.31.3.752-760.1979] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The sequence relations between Kirsten murine sarcoma virus (Ki-SV), Harvey murine sarcoma virus (Ha-SV), and a rat endogenous 30S RNA were studied by electron microscope heteroduplex analysis. The sequence relationships between the sarcoma viruses and their respective parental murine leukemia viruses (Kirsten and Moloney murine leukemia viruses), as well as between the two murine leukemia viruses, were also studied. The only observed nonhomology feature of the Kirsten murine leukemia virus/Moloney murine leukemia virus heteroduplexes was a substitution loop with two arms of equal length extending from 1.80 +/- 0.18 kilobases (kb) to 2.65 +/- 0.27 kb from the 3' end of the RNA. It is believed that this feature lies in the env gene region of the viral genomes. The Ha-SV and Moloney murine leukemia virus genomes (respective lengths, 6.0 and 9.0 kb) were homologous in a 1.0 +/- 0.05-kb region at the 3' end and possibly over a 200-nucleotide region at the 5' ends; otherwise, they were nonhomologous. Ha-SV and Ki-SV (length, 7.5 kb) were homologous in the first 4.36 +/- 0.37-kb region from the 3' end and in a 0.70 +/- 0.15-kb region at the 5' end. In between, there was a nonhomology region, possibly containing a short (0.23-kb) region of partial or total homology. The heteroduplex analysis between rat endogenous 30S RNA and Ki-SV shows that there are mixed regions of sequence homology and nonhomology at both the 5' and 3' ends. However, there is a large (4-kb) region of homology between Ki-SV and the rat 30S RNA in the center of the genomes, with only a small nonhomology hairpin feature. These studies help to define the regions of homology between the Ha-SV and Ki-SV genomes with each other and with the rat endogenous 30S RNA. These regions may be related to the sarcoma genicity of the viruses. In particular, the 0.7-kb region of homology of Ha-SV with Ki-SV at the 5' ends may be related to the formation of a 21,000-dalton phosphoprotein in cells transformed by either virus.
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Christie MR, Genovese S, Cassidy D, Bosi E, Brown TJ, Lai M, Bonifacio E, Bottazzo GF. Antibodies to islet 37k antigen, but not to glutamate decarboxylase, discriminate rapid progression to IDDM in endocrine autoimmunity. Diabetes 1994; 43:1254-9. [PMID: 7926297 DOI: 10.2337/diab.43.10.1254] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Apart from islet cell antibodies (ICAs), antibodies to glutamate decarboxylase (GAD), insulin autoantibodies (IAAs), and a novel islet antigen (37k antigen) are potential markers for insulin-dependent diabetes mellitus (IDDM). GAD is also an antigen in stiff-man syndrome (SMS), and both SMS and IDDM are associated with ICAs and autoimmunity to other endocrine organs. We investigated possible links between antibody responses to islet antigens with autoimmunity to other endocrine organs and determined which specific antibodies can identify individuals who progress to IDDM. Antibodies to GAD were detected in > or = 90% of both diabetic and nondiabetic patients with ICAs and other endocrine autoimmunity, in 59% of ICA-positive IDDM patients without endocrine autoimmunity, in all patients with SMS, but in only 1-3% of healthy (nondiabetic) and autoimmune disease control subjects. GAD antibody levels were increased in ICA-positive IDDM patients with polyendocrine autoimmunity compared with those without. In contrast, antibodies to 37k antigen were only detected in patients who developed acute-onset IDDM. IAAs were also associated with IDDM. Thus, certain factors enhance antibody responses to GAD in polyendocrine autoimmunity, but this does not necessarily lead to development of IDDM or SMS. Antibodies to 37k antigen are strongly associated with acute-onset IDDM and are useful serological markers for disease.
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Clinical Trial |
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Lai M, McCormick JA, Chapman KE, Kelly PAT, Seckl JR, Yau JLW. Differential regulation of corticosteroid receptors by monoamine neurotransmitters and antidepressant drugs in primary hippocampal culture. Neuroscience 2003; 118:975-84. [PMID: 12732243 DOI: 10.1016/s0306-4522(03)00038-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hyperactivity of the hypothalamic-pituitary-adrenal axis is a characteristic feature of depressive illness. The centrally located corticosteroid receptors, the glucocorticoid and mineralocorticoid receptors, are thought to be important modulators of this axis and changes in the levels of these receptors, particularly in the hippocampus, may underlie the hyperactivity observed. Various antidepressant drugs increase hippocampal mineralocorticoid and glucocorticoid receptor levels in vivo. These effects are thought to be mediated via alterations in monoaminergic neurotransmission. We examined whether serotonin (5HT) and noradrenaline (NA) have direct effects on glucocorticoid receptor and mineralocorticoid receptor expression in primary hippocampal neurones, and whether antidepressants also exert direct effects on target neurones. Exposure of hippocampal cells to 5HT for 4 days increased both glucocorticoid and mineralocorticoid receptor mRNA and protein expression. The induction of mineralocorticoid receptor mRNA was completely blocked by the 5HT(7) receptor antagonist SB 269970. In contrast glucocorticoid receptor induction was insensitive to the 5HT(7) receptor, whilst studies with the 5HT(1A) receptor agonist 8-hydroxy-2-(di-n-proplamino) tetralin hydrochloride and the 5HT(1A) receptor antagonist N-[2-[4-2-[O-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexane carboxamide trihydrochloride (WAY 100635) suggest a partial role for 5HT(1A) receptors in hippocampal glucocorticoid receptor regulation. Treatment with NA for 4 days also increased glucocorticoid receptor expression but had no effect on mineralocorticoid receptor expression. This was blocked by propanolol suggesting action via beta-adrenergic receptors. Similarly to NA, fluoxetine and amitriptyline also selectively increased glucocorticoid receptor mRNA and protein levels over this time course. However, glucocorticoid receptor induction by fluoxetine or amitriptyline was not blocked by WAY 100635 or propanolol. These results show that 5HT, NA and antidepressants act directly but via distinct mechanisms on hippocampal neurones to regulate mineralocorticoid and glucocorticoid receptor expression. Thusly, manipulation of neurotransmitter or antidepressant levels in the brain may aid in reversing hypothalamic-pituitary-adrenal axis hyperactivity by restoring hippocampal corticosteroid receptor balance.
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MESH Headings
- 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology
- Adrenergic beta-Antagonists/pharmacology
- Amitriptyline/pharmacology
- Animals
- Animals, Newborn
- Antidepressive Agents/pharmacology
- Biogenic Monoamines/pharmacology
- Blotting, Western/methods
- Carrier Proteins/biosynthesis
- Carrier Proteins/genetics
- Culture Techniques
- DNA Primers/metabolism
- DNA, Complementary/biosynthesis
- Drug Interactions/genetics
- Female
- Fluoxetine/pharmacology
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Hippocampus/drug effects
- Hippocampus/metabolism
- Membrane Glycoproteins/biosynthesis
- Membrane Glycoproteins/genetics
- Membrane Transport Proteins
- Nerve Tissue Proteins
- Phenols/pharmacology
- Piperazines/pharmacology
- Pregnancy
- Propranolol/pharmacology
- Pyridines/pharmacology
- RNA, Messenger/biosynthesis
- Rats
- Rats, Wistar
- Receptors, Adrenergic/biosynthesis
- Receptors, Adrenergic/genetics
- Receptors, Serotonin/biosynthesis
- Receptors, Serotonin/genetics
- Receptors, Steroid/genetics
- Receptors, Steroid/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Serotonin Plasma Membrane Transport Proteins
- Serotonin Receptor Agonists/pharmacology
- Selective Serotonin Reuptake Inhibitors/pharmacology
- Sulfonamides/pharmacology
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Comparative Study |
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Giovannoni G, Lai M, Thorpe J, Kidd D, Chamoun V, Thompson AJ, Miller DH, Feldmann M, Thompson EJ. Longitudinal study of soluble adhesion molecules in multiple sclerosis: correlation with gadolinium enhanced magnetic resonance imaging. Neurology 1997; 48:1557-65. [PMID: 9191766 DOI: 10.1212/wnl.48.6.1557] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVE To assess whether serial serum levels of soluble forms of intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1) are useful as surrogate markers of disease activity in multiple sclerosis (MS). BACKGROUND Increased levels of sICAM-1 and sVCAM-1 have been described in cross-sectional, but not longitudinal, studies of patients with MS. Although they appear to correlate with clinical and MRI markers of disease activity, their role as potential surrogate markers remains undefined. METHODS Serial serum levels of sICAM-1 and sVCAM-1 were measured in patients with MS undergoing monthly gadolinium-enhanced MRI studies of the brain (462 gadolinium-enhanced MRI in 57 patients) and in 12 normal control subjects. Ten patients had primary progressive (PP), 22 relapsing remitting (RR), and 25 secondary progressive (SP) disease. RESULTS Levels of sICAM-1 and sVCAM-1 were increased intermittently in patients with all subtypes of MS. Median levels of sICAM-1 were elevated in patients with MS compared with normal controls (normal controls median [interquartile range] = 176[119-209] compared with PP = 502[194-1768], RR = 419[158-481], and SP = 352[196-469] ng/mL; p = 0.04). After excluding patients with PP MS, patients with high sICAM-1 levels had a greater number of gadolinium-enhancing lesions per study (1.9[0.9-4.3]) than patients with normal levels (0.4[0-2.7], p = 0.03), and patients with MRI studies with no gadolinium-enhancing lesions had lower associated sICAM-1 levels (200 ng/mL[85-561]) than patients with only persistent (349 ng/mL[82-615]) or new enhancing lesions (497 ng/mL[108-667], p = 0.03). Patients with RR or SP disease that progressed clinically during the study had a greater number of gadolinium-enhancing lesions per MRI study (3.5[0.4-5.5]) than did patients in whom disease did not progress (1.2 [0.3-2.7], p = 0.03). The patients with progressive disease tended to have higher sICAM-1 levels (469 ng/mL [196-1019]) than patients in whom disease did not progress (353 ng/mL [171-469], p = 0.07). Although MS patients tended to have higher sVCAM-1 levels than did normal controls, this finding was not significant. No correlation could be found between levels of sVCAM-1 and gadolinium enhancement on MRI. CONCLUSIONS Patients with MS have elevated levels of sICAM-1, which correlate with gadolinium enhancement on MRI and possibly short-term disease progression. Soluble ICAM-1, and not sVCAM-1, may therefore be suitable as a long-term surrogate marker of disease activity in MS.
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Lau JS, Baumeister P, Kim E, Roy B, Hsieh TY, Lai M, Lee AS. Heterogeneous nuclear ribonucleoproteins as regulators of gene expression through interactions with the human thymidine kinase promoter. J Cell Biochem 2000; 79:395-406. [PMID: 10972977 DOI: 10.1002/1097-4644(20001201)79:3<395::aid-jcb50>3.0.co;2-m] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In search for nuclear proteins that interact with the human thymidine kinase (htk) promoter, we discovered that p37AUF, a hnRNP C-like protein, and hnRNP A1, both members of the heterogeneous ribonucleoprotein family, can bind with high affinity to an ATTT sequence motif contained within the cell cycle regulatory unit (CCRU). We report here that over-expression of p37AUF stimulates gene expression mediated by the htk promoter in a promoter-sequence specific manner, whereas hnRNP A1 suppresses it. Both recombinant p37AUF and hnRNP A1 can bind the htk CCRU, suggesting that their binding to the DNA target does not require additional cellular components. We further discovered that hnRNP K is a potent suppressor of htk mediated gene activity. However, its mechanism of action is mediated through protein-protein interaction, since hnRNP K itself cannot bind the htk CCRU but can competitively inhibit the binding of other hnRNPs. The binding site for the hnRNPs on the htk CCRU is not required for S-phase induction of the htk promoter. However, in stable but not transient transfectants, the mutation of the hnRNP binding site results in 5- to 10-fold reduction of htk mediated gene activity in synchronized and exponentially growing cells. Collectively, these findings support emerging evidence that hnRNPs, in addition to their traditional role in RNA biogenesis, could be regulators of gene expression through direct DNA binding or interaction with other proteins.
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Comparative Study |
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Lai M, Sirimanne E, Williams CE, Gluckman PD. Sequential patterns of inhibin subunit gene expression following hypoxic-ischemic injury in the rat brain. Neuroscience 1996; 70:1013-24. [PMID: 8848164 DOI: 10.1016/0306-4522(95)00413-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Injury to the central nervous system initiates a series of signals that control cell survival and rearrangement, leading to some functional recovery. Using a unilateral model of hypoxic-ischemic brain injury, we report strong induction of inhibin beta A and alpha subunit messenger RNA in several regions of the brain and provide evidence for novel roles for the inhibin/activin family of peptides in modulating neural function. Expression was visualized by in situ hybridization and the beta A subunit was observed as early as 1 h after injury in the dentate gyrus of the non-ligated hemisphere. Strong induction was seen in the hippocampus, piriform cortex and amygdala on the non-ligated hemisphere 24 h after injury. The early induction of inhibin beta A was associated with seizure activity, since administration of the anticonvulsant carbamazepine (8 mg/kg) markedly attenuated the signal. Only background expression was observed for the alpha and beta B subunits at these early time points. A bilateral induction of both beta A and alpha subunit messenger RNA was demonstrated in the meningeal membrane from three to seven days after injury. This second wave was not blocked by carbamazepine. Thirdly, beta A and alpha subunit expression was observed in the infarct from days 5 to 7. However, expression was not co-localized with isolectin B4 staining for reactive microglia or astrocytes, but instead the pattern of distribution strongly suggested that inhibin/activin was induced around microvessels. These data demonstrated three distinct waves of beta A subunit expression following hypoxic-ischemic injury, two of which coincided with alpha subunit expression. The early induction of beta A subunit was seizure related, whereas subsequent co-induction of beta A and alpha subunit suggested involvement in vascular and meningeal reactions. These results suggest specific roles for both activin and inhibin in the central nervous system during recovery from injury.
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Rossetti ZL, Lai M, Hmaidan Y, Gessa GL. Depletion of mesolimbic dopamine during behavioral despair: partial reversal by chronic imipramine. Eur J Pharmacol 1993; 242:313-5. [PMID: 8281997 DOI: 10.1016/0014-2999(93)90257-i] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Exposure of rate to the behavioral despair test (an animal model of depression) for 40 min resulted in a long-lasting depletion of mesolimbic dopamine output to about 40% of baseline values. The decrease in extracellular dopamine was partially prevented by chronic pretreatment with imipramine (20 mg/kg per day i.p. for 21 days). The results suggest that a fall in mesolimbic dopamine output may be associated with depressive states and indicate that changes in the functional status of the dopamine system contribute to the mechanism of action of imipramine.
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