1
|
Yin Y, Yan Y, Jiang X, Mai J, Chen NC, Wang H, Yang XF. Inflammasomes are differentially expressed in cardiovascular and other tissues. Int J Immunopathol Pharmacol 2009; 22:311-22. [PMID: 19505385 DOI: 10.1177/039463200902200208] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
To determine the expression of components in Toll-like receptors (TLRs)/Nod-like receptors (NLRs)/inflammasome/caspase-1/interleukin (IL-1)-beta pathway, we examined the expression profiles of those genes by analyzing the data from expression sequence tag cDNA cloning and sequencing. We made several important findings: firstly, among 11 tissues examined, vascular tissues and heart express fewer types of TLRs and NLRs than immune and defense tissues including blood, lymph nodes, thymus and trachea; secondly, brain, lymph nodes and thymus do not express proinflammatory cytokines IL-1beta and IL-18 constitutively, suggesting that these two cytokines need to be upregulated in the tissues; and thirdly, based on the expression data of three characterized inflammasomes (NALP1, NALP3 and IPAF inflammasome), the examined tissues can be classified into three tiers: the first tier tissues including brain, placenta, blood and thymus express inflammasome(s) in constitutive status; the second tier tissues have inflammasome(s) in nearly-ready expression status (with the requirement of upregulation of one component); the third tier tissues, like heart and bone marrow, require upregulation of at least two components in order to assemble functional inflammasomes. Our original model of three-tier expression of inflammasomes would suggest a new concept of tissue inflammation privilege, and provides an insight to the differences among tissues in initiating acute inflammation in response to stimuli.
Collapse
|
Journal Article |
16 |
145 |
2
|
Mai J, Finley RL, Waisman DM, Sloane BF. Human procathepsin B interacts with the annexin II tetramer on the surface of tumor cells. J Biol Chem 2000; 275:12806-12. [PMID: 10777578 DOI: 10.1074/jbc.275.17.12806] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
To study potential roles of plasma membrane-associated extracellular cathepsin B in tumor cell invasion and metastasis, we used the yeast two-hybrid system to screen for proteins that interact with human procathepsin B. The annexin II light chain (p11), one of the two subunits of the annexin II tetramer, was one of the proteins identified. We have confirmed that recombinant human procathepsin B interacts with p11 as well as with the annexin II tetramer in vitro. Furthermore, procathepsin B could interact with the annexin II tetramer in vivo as demonstrated by coimmunoprecipitation. Cathepsin B and the annexin II tetramer were shown by immunofluorescent staining to colocalize on the surface of human breast carcinoma and glioma cells. Taken together, our results indicate that the annexin II tetramer can serve as a binding protein for procathepsin B on the surface of tumor cells, an interaction that may facilitate tumor invasion and metastasis.
Collapse
|
|
25 |
141 |
3
|
Kinsella JE, Shimp JL, Mai J, Weihrauch J. Fatty acid content and composition of freshwater finfish. J AM OIL CHEM SOC 1977; 54:424-9. [PMID: 915171 DOI: 10.1007/bf02671025] [Citation(s) in RCA: 134] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
|
48 |
134 |
4
|
Mai J, Waisman DM, Sloane BF. Cell surface complex of cathepsin B/annexin II tetramer in malignant progression. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1477:215-30. [PMID: 10708859 DOI: 10.1016/s0167-4838(99)00274-5] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cysteine protease cathepsin B is upregulated in a variety of tumors, particularly at the invasive edges. Cathepsin B can degrade extracellular matrix proteins, such as collagen IV and laminin, and can activate the precursor form of urokinase plasminogen activator (uPA), perhaps thereby initiating an extracellular proteolytic cascade. Recently, we demonstrated that procathepsin B interacts with the annexin II heterotetramer (AIIt) on the surface of tumor cells. AIIt had previously been shown to interact with the serine proteases: plasminogen/plasmin and tissue-type plasminogen activator (tPA). The AIIt binding site for cathepsin B differs from that for either plasminogen/plasmin or tPA. AIIt also interacts with extracellular matrix proteins, e.g., collagen I and tenascin-C, forming a structural link between the tumor cell surface and the extracellular matrix. Interestingly, cathepsin B, plasminogen/plasmin, t-PA and tenascin-C have all been linked to tumor development. We speculate that colocalization through AIIt of proteases and their substrates on the tumor cell surface may facilitate: (1) activation of precursor forms of proteases and initiation of proteolytic cascades; and (2) selective degradation of extracellular matrix proteins. The recruitment of proteases to specific regions on the cell surface, regions where potential substrates are also bound, could well function as a 'proteolytic center' to enhance tumor cell detachment, invasion and motility.
Collapse
|
Review |
25 |
129 |
5
|
Balsiger BM, Poggio JL, Mai J, Kelly KA, Sarr MG. Ten and more years after vertical banded gastroplasty as primary operation for morbid obesity. J Gastrointest Surg 2000; 4:598-605. [PMID: 11307094 DOI: 10.1016/s1091-255x(00)80108-0] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Long-term follow-up (>10 years) after vertical banded gastroplasty (VBG) is almost nonexistent. The aim of this study was to determine long-term outcome after VBG in a group of 71 patients studied prospectively. Seventy-one consecutive patients with morbid obesity (54 women and 17 men; mean age 40 years [range 22 to 71 years]) underwent VBG from 1985 to 1989 and were followed prospectively. Follow-up was obtained in 70 (99%) of the 71 patients. Weight (mean +/- standard error of the mean) preoperatively was 138 +/- 3 kg and decreased to 108 +/- 2 kg 10 or more years postoperatively. Body mass index decreased from 49 +/-1 to 39 +/- 1. Only 14 (20%) of 70 patients lost and maintained the loss of at least half of their excess body weight with the VBG anatomy. Vomiting one or more times per week continues to occur in 21% and heartburn in 16%. Fourteen patients have undergone conversion from VBG to Roux-en-Y gastric bypass (11 patients) or other procedures (3 patients) because of a combination of inadequate weight loss in 13 patients, gastroesophageal reflux in five, and frequent vomiting in four. Only 26% of patients after VBG have maintained a weight loss of at least 50% of their excess body weight; 17% underwent bariatric reoperation with good results. Thus VBG is not an effective, durable bariatric operation.
Collapse
|
Comparative Study |
25 |
117 |
6
|
Kinsella JE, Bruckner G, Mai J, Shimp J. Metabolism of trans fatty acids with emphasis on the effects of trans, trans-octadecadienoate on lipid composition, essential fatty acid, and prostaglandins: an overview. Am J Clin Nutr 1981; 34:2307-18. [PMID: 6794350 DOI: 10.1093/ajcn/34.10.2307] [Citation(s) in RCA: 111] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Information concerning the metabolism of trans isomers of dietary unsaturated fatty acids is presented. Dietary trans-octadecenoic and trans,trans-octadecadienoic acids are apparently absorbed, activated, oxidized, and acylated into ester lipids much like saturated fatty acids although differences have been observed with regard to their metabolism by different organs. Because of the important role of linoleic acid as the principal precursor of cyclic endoperoxides, prostaglandins and leukotrienes, the potential deleterious effects of trans isomers of this acid are discussed. High levels of dietary trans,trans lineoleate can impair delta 6 desaturase activity and decrease prostaglandin production in rats on experimental diets.
Collapse
|
|
44 |
111 |
7
|
Mi Z, Mai J, Lu X, Robbins PD. Characterization of a class of cationic peptides able to facilitate efficient protein transduction in vitro and in vivo. Mol Ther 2000; 2:339-47. [PMID: 11020349 DOI: 10.1006/mthe.2000.0137] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Protein transduction domains (PTDs), such as the third helix of the Drosophila Antennapedia homeobox gene (Antp) and the HIV TAT PTD, possess a characteristic positive charge on the basis of their enrichment for arginine and lysine residues. To determine whether cationic peptides are able to function as protein transduction domains, 12-mer peptide sequences from an M13 phage library were selected for synthesis on the basis of their varying cationic charge content. In addition, polylysine and polyarginine peptides were synthesized in order to assess the effect of charge contribution in protein transduction. Coupling of the biotinylated peptides to avidin-beta-galactosidase facilitated transduction in a wide variety of cell lines and primary cells, including islet beta-cells, synovial cells, polarized airway epithelial cells, dendritic cells, myoblasts, and tumor cells. Two of the peptides, PTD-4 and PTD-5, mediated transduction nearly 600-fold more efficiently than a random control peptide, but with an efficiency similar to the TAT PTD and the 12 mers of polylysine and polyarginine. Furthermore, confocal analysis of biotinylated peptide-streptavidin-Cy3 conjugates demonstrated that the internalized PTDs are found in both the nuclei and the cytoplasm of treated cells. When tested in vivo, the PTDs were able to facilitate efficient and rapid protein delivery into rabbit synovium and mouse solid tumors following intraarticular and intratumoral administration, respectively. These novel PTDs can be used to transfer therapeutic proteins and DNA for the treatment of a wide variety of diseases, including arthritis and cancer.
Collapse
|
|
25 |
107 |
8
|
Balsiger BM, Murr MM, Mai J, Sarr MG. Gastroesophageal reflux after intact vertical banded gastroplasty: correction by conversion to Roux-en-Y gastric bypass. J Gastrointest Surg 2000; 4:276-81. [PMID: 10769090 DOI: 10.1016/s1091-255x(00)80076-1] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Symptomatic gastroesophageal reflux disease is common in our experience after vertical banded gastroplasty. Our aim was to determine the safety and efficacy of Roux-en-Y gastric bypass in the treatment of symptomatic gastroesophageal reflux disease complicating vertical banded gastroplasty. We evaluated prospectively collected data on 25 patients who underwent revisional bariatric surgery because of severe gastroesophageal reflux disease after vertical banded gastroplasty. Only 4 of 25 patients had gastroesophageal reflux disease symptoms prior to vertical banded gastroplasty. Endoscopic findings in 24 patients included esophagitis (58%), Barrett's esophagus (28%), pouchitis (29%), and gastritis (21%);7 (28%) of 25 patients had evidence of stenosis at the pouch outlet. Mean follow-up (complete in all 25) after Roux-en-Y gastric bypass was 37 +/- 7 months (range 3 to 102 months). There were no deaths. Postoperative complications occurred in six patients: pneumonia in two, wound infection in two, prolonged drainage of the defunctionalized stomach via gastrostomy in one, and fever in one. Median hospitalization was 7 days (range 5 to 43 days). At follow-up (37 +/- 7 months), 24 (96%) of 25 are completely or almost completely symptom free. Body mass index was 33 +/- 2 kg/m(2) before and 28 +/- 2 kg/m(2) after Roux-en-Y gastric bypass (P = 0. 001). Symptoms of gastroesophageal reflux disease are common after vertical banded gastroplasty. Conversion to Roux-en-Y gastric bypass is safe, relieves gastroesophageal reflux disease, and promotes further weight loss. Moreover, maladaptive eating (vomiting, and so forth) induced by vertical banded gastroplasty is relieved.
Collapse
|
|
25 |
82 |
9
|
Guo L, Yang J, Mai J, Du X, Guo Y, Li P, Yue Y, Tang D, Lu C, Zhang WH. Prevalence and associated factors of myopia among primary and middle school-aged students: a school-based study in Guangzhou. Eye (Lond) 2016; 30:796-804. [PMID: 26965016 DOI: 10.1038/eye.2016.39] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/04/2016] [Indexed: 11/09/2022] Open
Abstract
PurposeTo estimate the prevalence of myopia among primary and middle school-aged students in Guangzhou and to explore the potentially contributing factors to myopia.MethodsThis cross-sectional study was based on a sample of students in grades 1-6 and grades 7-9. Data were collected from refractive error measurements and a structured questionnaire.ResultsA total of 3055 participants were involved in this analysis, and the overall prevalence of myopia was 47.4% (95% confidence interval (CI)= 45.6-49.2%). The prevalence of myopia in students increased along with the growth of grade level; the prevalence of myopia in students in grade 1 was only 0.2%, as it increased to 38.8% in students in grade 3, and the rate was the highest (68.4%) in students in grade 9. Girls were at a higher risk of myopia than boys (adjusted odds ratio=1.22, 95% CI=1.04-1.44). Both male and female students whose distance of reading was longer than 25 cm were less likely to have myopia and who have one or two myopic parents were at a higher risk of myopia. In addition, reading for pleasure more than 2 h per day (adjusted odds ratio=1.84, 95% CI=1.09-3.12) was only positively associated with myopia in boys and spending time watching television per week was only positively associated with myopia in girls.ConclusionMyopia in students is a significant public health problem in Guangzhou. Female gender, higher grade, longer time spent for near work, shorter distance of near work, and parental myopia were shown to be associated with the increasing risk of myopia in children.
Collapse
|
Journal Article |
9 |
78 |
10
|
Lam LT, Peng Z, Mai J, Jing J. The association between internet addiction and self-injurious behaviour among adolescents. Inj Prev 2010; 15:403-8. [PMID: 19959733 DOI: 10.1136/ip.2009.021949] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To examine the association between internet addiction and self-injurious behaviour (SIB) in adolescence. METHODS Population-based cross-sectional survey of 1618 high school students aged 13-18 years in Guangzhou city, Guangdong Province, PR China. Deliberate SIB was measured using self-reported questionnaire; internet addiction was assessed using the Internet Addiction Test (IAT). RESULTS 263 (16.3%) participants reported having committed some form of SIB in the past 6 months. 73 (4.5%) had committed SIB 6 times or more, and 157 (9.7%) 1-5 times. The majority of respondents were classified as normal users of the internet (n = 1392, 89.2%), with 158 (10.2%) moderately and 10 (0.6%) severely addicted to the internet. After adjusting for potential confounders, the odds ratio for SIB was 2.0 (95% CI 1.1 to 3.7) for those who were classified as moderately and severely addicted to the internet when compared to the normal group. CONCLUSIONS SIB is common in adolescence in the study population in China. Addiction to the internet is detrimental to mental health and increases the risk of self-injury among adolescents. Clinicians need to be aware of potential co-morbidities of other addictions among adolescent self-injured patients.
Collapse
|
Journal Article |
15 |
70 |
11
|
Greve E, Mai J. Cluster headache-like headaches: a symptomatic feature? A report of three patients with intracranial pathologic findings. Cephalalgia 1988; 8:79-82. [PMID: 3401920 DOI: 10.1046/j.1468-2982.1988.0802079.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
This report concerns three patients with cluster headache-like headaches associated with intracranial pathologic findings. The question whether the occurrence of cluster headache-like headaches may be a symptomatic feature is still not solved. In two of the three presented cases the cluster headache-like headaches disappeared when the intracranial abnormalities were treated.
Collapse
|
Case Reports |
37 |
50 |
12
|
Kermer P, Krajewska M, Zapata JM, Takayama S, Mai J, Krajewski S, Reed JC. Bag1 is a regulator and marker of neuronal differentiation. Cell Death Differ 2002; 9:405-13. [PMID: 11965493 DOI: 10.1038/sj.cdd.4400972] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2001] [Accepted: 10/10/2001] [Indexed: 11/08/2022] Open
Abstract
Bag 1 acts as a co-chaperone for Hsp70/Hsc70. We report here that stable over-expression of Bag1 in immortalized neuronal CSM14.1 cells prevents death following serum deprivation. Bag1 over-expression slowed the proliferative rate of CSM14.1 cells, resulted in increased levels of phospo-MAP kinases and accelerated neuronal differentiation. Immunocytochemistry revealed mostly nuclear localization of Bag1 protein in these cells. However, during differentiation in vitro, Bag1 protein shifted from predominantly nuclear to mostly cytosolic in CSM14.1 cells. To explore in vivo parallels of these findings, we investigated Bag1 expression in the developing mouse nervous system using immunohistochemical methods. Early in brain development, Bag1 was found in nuclei of neuronal precursor cells, whereas cytosolic Bag1 staining was observed mainly after completion of neuronal precursor migration and differentiation. Taken together, these findings raise the possibility that the Bag1 protein is expressed early in neurogenesis in vivo and is capable of modulating neuronal cell survival and differentiation at least in part from a nuclear location.
Collapse
|
|
23 |
49 |
13
|
Pedersen E, Arlien-Soborg P, Mai J. The mode of action of the gaba derivative baclofen in human spasticy. Acta Neurol Scand 2009; 50:665-80. [PMID: 4155219 DOI: 10.1111/j.1600-0404.1974.tb02813.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
|
16 |
47 |
14
|
Wu Y, Vollmer WM, Buist AS, Tsai R, Cen R, Wu X, Chen P, Li Y, Guo C, Mai J, Davis CE. Relationship between lung function and blood pressure in Chinese men and women of Beijing and Guangzhou. PRC-USA Cardiovascular and Cardiopulmonary Epidemiology Research Group. Int J Epidemiol 1998; 27:49-56. [PMID: 9563693 DOI: 10.1093/ije/27.1.49] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Previous studies of western populations have shown an inverse association between lung function and blood pressure. METHODS As part of a People's Republic of China-United States cardiopulmonary epidemiology study, we investigated the cross-sectional relationship between lung function and blood pressure in 6757 Chinese men and women, aged 35-54, from Beijing and Guangzhou, China. We also evaluated the longitudinal association between lung function and incident hypertension among 4818 initially normotensive subjects followed up between 2 and 4 years later. RESULTS In our cross-sectional analyses of baseline data, lung function varied inversely with baseline systolic (SBP) and diastolic blood pressure (DBP) in all women and in Beijing men. This association held for absolute and height-standardized forced vital capacity (FVC) and one-second forced expiratory volume (FEV1) (correlations: 0.10, -0.18, P < 0.0001), but was weaker after adjustment for age (correlations: -0.02, -0.11). The longitudinal follow-up showed that lower initial lung function levels were associated with a higher incidence of hypertension (SBP > or = 140 mmHg or DBP > or = 90 mmHg or currently using antihypertensive medications), but only among women in Guangzhou. Relative risks for hypertension incidence for those in the two lowest quintiles for FEV1 and FVC, compared to those in the two highest quintiles, ranged from 1.9 to 2.3 for Guangzhou women and from 0.9 to 1.4 for all other gender-city subgroups. Logistic regression analyses adjusting for age, baseline SBP, body mass index, smoking, education, and urban versus rural setting generally confirmed these patterns. CONCLUSIONS These results suggest a statistically significant, though weak, inverse relationship between lung function and blood pressure in Chinese men and women. This association is largely attributable to age and is present prospectively only in women.
Collapse
|
|
27 |
34 |
15
|
Mai J, Goswami SK, Bruckner G, Kinsella JE. A new prostaglandin, C22-PGF4 alpha, synthesized from docosahexaenoic acid (C22:6n3) by trout gill. PROSTAGLANDINS 1981; 21:691-8. [PMID: 6280241 DOI: 10.1016/0090-6980(81)90226-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The concentrations of prostaglandins PGE3 and PGF3 alpha were 214 and 1500 ng/g wet trout gill tissue, respectively. A new prostaglandin, tentatively identified by gas chromatography/mass spectrometry as C22-PGF4 alpha (590 ng/g wet tissue) was discovered. This was synthesized from docosahexaenoic acid.
Collapse
|
|
44 |
32 |
16
|
Johannsen P, Velander G, Mai J, Thorling EB, Dupont E. Glutathione peroxidase in early and advanced Parkinson's disease. J Neurol Neurosurg Psychiatry 1991; 54:679-82. [PMID: 1940936 PMCID: PMC1014468 DOI: 10.1136/jnnp.54.8.679] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A defective antioxidant scavenging system plays a major role in one of the theories of the pathogenesis of Parkinson's disease. The aim of this study was to investigate whether there is a general difference in antioxidant activity between early and advanced cases of Parkinson's disease. Twenty five recently diagnosed patients, without any clinical fluctuations (group A), and 25 patients in a late phase of the disease with severe fluctuations in response to levodopa therapy (group B) were included in the study. Erythrocyte glutathione peroxidase was determined as a measure of antioxidant activity and significantly lower values were found in group B than in group A. Regression analyses in groups A and B showed significant correlation between glutathione peroxidase and duration of disease, but not between glutathione peroxidase and age of patients.
Collapse
|
research-article |
34 |
31 |
17
|
Mai J, Sokolov IM, Blumen A. Directed particle diffusion under "burnt bridges" conditions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 64:011102. [PMID: 11461220 DOI: 10.1103/physreve.64.011102] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2000] [Indexed: 05/23/2023]
Abstract
We study random walks on a one-dimensional lattice that contains weak connections, so-called "bridges." Each time the walker crosses the bridge from the left or attempts to cross it from the right, the bridge may be destroyed with probability p; this restricts the particle's motion and directs it. Our model, which incorporates asymmetric aspects in an otherwise symmetric hopping mechanism, is very akin to "Brownian ratchets" and to front propagation in autocatalytic A+B-->2A reactions. The analysis of the model and Monte Carlo simulations show that for large p the velocity of the directed motion is extremely sensitive to the distribution of bridges, whereas for small p the velocity can be understood based on a mean-field analysis. The single-particle model advanced by us here allows an almost quantitative understanding of the front's position in the A+B-->2A many-particle reaction.
Collapse
|
|
24 |
27 |
18
|
Mai J, Erickson B, Rownd J, Gillin M. Comparision of four different dose specification methods for high-dose-rate intracavitary radiation for treatment of cervical cancer. Int J Radiat Oncol Biol Phys 2001; 51:1131-41. [PMID: 11704338 DOI: 10.1016/s0360-3016(01)01771-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To compare the dose delivered to target tissues and dose-limiting structures as defined by specific dose points with high-dose-rate intracavitary brachytherapy using tandem and ring or tandem and ovoids applicators, and to provide a reasonable approach to dose optimization. METHODS AND MATERIALS Dosimetry was obtained using four different dose specifications: (1) 100% of the dose prescribed in a tapered fashion along the tandem and 140% at the ovoid/ring surface, (2) 100% of the dose prescribed along the tandem and 100% at the ovoid/ring surface, (3) 100% of the dose prescribed to point A without any additional applicator specification points, and (4) nonoptimized plan using relative dwell weighting to simulate classic Fletcher low-dose-rate (LDR) loading with the dose specified at point A. Point doses were recorded at A, B, and T (cervical tumor point), ICRU rectum, and ovoid/ring surface. RESULTS For the tandem and ovoids applicators, significant differences were found among the four different dose specification methods for point T and vaginal mucosal doses. When the dose was optimized to point A alone, the ovoid dwell weights were reduced, resulting in higher point T doses and underdosing of the vaginal mucosa. Fixed weighting based on Fletcher LDR loading specifications resulted in higher vaginal mucosa doses. For the tandem and ring applicators, significant differences were observed for vaginal mucosal doses and the ICRU rectal dose. Optimization to point A alone resulted in widely varying dosimetric distributions and vaginal mucosa doses up to 632% of the prescription dose. With nonoptimized fixed weighting, the vaginal wall dose and ICRU rectal dose were increased. CONCLUSION Prescribing to dose optimization points in a tapered fashion along the tandem and at the ovoid/ring surface results in a pear-shaped dose distribution resembling classic LDR systems. The other dose specification methods may result in underdosing of important target tissues or overdosing of adjacent dose-limiting structures.
Collapse
|
Comparative Study |
24 |
26 |
19
|
Mai J, Sørensen PS, Hansen JC. High dose antioxidant supplementation to MS patients. Effects on glutathione peroxidase, clinical safety, and absorption of selenium. Biol Trace Elem Res 1990; 24:109-17. [PMID: 1702664 DOI: 10.1007/bf02917200] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
High-dose antioxidant supplementation has recently been recommended for multiple sclerosis (MS) patients. This study tests the clinical safety, the glutathione peroxidase (GSH-px) activity, and the absorption of selenium during such supplementation. Eighteen MS patients were given 6 tablets especially made for this study, equivalent to 6 mg sodium selenite, 2 g vitamin C, and 480 mg vitamin E a day for five wk. GSH-px, which was lower than in non-MS controls before the start of treatment, increased fivefold during 5 wk of treatment. Side effects were scarce. Ten MS patients were subjected to a 24-h selenium absorption study after ingestion of 2 active tablets, equivalent to 2 mg sodium selenite. Selenium, which was low initially, increased 24% during the first 3 h and then stabilized. It is concluded that the tested antioxidant treatment seems to be safe and that MS patients have low GSH-px, which may be increased by the tested antioxidant treatment.
Collapse
|
|
35 |
24 |
20
|
Moin K, Demchik L, Mai J, Duessing J, Peters C, Sloane BF. Observing proteases in living cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2001; 477:391-401. [PMID: 10849765 DOI: 10.1007/0-306-46826-3_40] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The lysosomal cysteine protease cathepsin B has been implicated in tumor progression and metastasis in part due to its altered trafficking. In order to analyze the trafficking of cathepsin B in living cells, we utilized enhanced green fluorescent protein (EGFP) fused to various cathepsin B constructs for transfecting two cell lines: an invasive human breast adenocarcinoma cell line (BT20) and a cathepsin B deficient mouse embryonic fibroblast cell line (MEF T -/-). The cells were transiently transfected with four cathepsin B-EGFP fusion constructs: full-length preprocathepsin B-EGFP, cathepsin B preregion-EGFP, cathepsin B prepro region-EGFP, and cathepsin B prepro region-EGFP with a mutation of the glycosylation site in the pro region. The full length construct showed vesicular distribution throughout the cells in both cell lines. In both BT20 and MEF T -/- cells, preregion-EGFP was localized in a ring tightly associated with the cell nucleus, suggesting distribution to the endoplasmic reticulum. The distribution of the prepro region-EGFP construct was similar except that it also included some patchy areas adjacent to the nucleus. This suggested that the cathepsin B prepro region-EGFP might have entered the Golgi. Distribution of the mutated cathepsin B prepro region-EGFP was similar to that of wild-type prepro region-EGFP in the MEF T -/-. In the invasive BT20 cells, however, the mutated prepro region-EGFP showed a vesicular distribution throughout the cytoplasm and in cell processes. This distribution is similar to that of endogenous cathepsin B in these cells. Our results suggest that: 1) tumor cells have an alternative mechanism for trafficking of cathepsin B which is independent of the mannose-6-phosphate receptor pathway, and 2) the pro region of cathepsin B may contain the sorting sequence necessary for its trafficking via this pathway.
Collapse
|
|
24 |
23 |
21
|
Goswami S, Mai J, Bruckner G, Kinsella JE. Extraction and purification of prostaglandins and thromboxane from biological samples for gas chromatographic analysis. PROSTAGLANDINS 1981; 22:693-702. [PMID: 7330223 DOI: 10.1016/0090-6980(81)90208-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
An efficient extraction procedure for the isolation of prostaglandins (PGs) from biological samples for their subsequent quantification by gas chromatography-electron capture detection (GC-ECD) is described. PGs were extracted from lung, kidney, spleen and stomach fundus into ethyl acetate at different pHs. The highest recovery and least extraction of contaminating pigments was obtained at pH 4.5. Pigments and other contaminants are removed by thin layer chromatography using a solvent system chloroform-isopropyl alcohol-ethanol-formic acid (45:5:0.5:0.3). The isolated PGs were determined by GC-ECD after appropriate derivatization. The overall recovery of PGs using this procedure is 60%.
Collapse
|
Comparative Study |
44 |
21 |
22
|
Kinsella JE, Hwang DH, Yu P, Mai J, Shimp J. Prostaglandins and their precursors in tissues from rats fed on trans, trans-linoleate. Biochem J 1979; 184:701-4. [PMID: 540059 PMCID: PMC1161857 DOI: 10.1042/bj1840701] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Feeding trans,trans-9,12-linoleate to rats as 50 and 100% of the dietary fat decreased the concentrations of n-6 fatty acids, i.e. 18:2, 20:3 and 20:4, in heart, kidney, lung, adipose tissue and platelets of rats. The concentrations of prostaglandin products prostaglandins E1, E2 and F2 alpha in serum were significantly decreased in rats receiving high concentrations of dietary trans, trans-linoleate.
Collapse
|
research-article |
46 |
21 |
23
|
Tran A, O'Mahoney T, Rey E, Mai J, Mumford JP, Olive G. Vigabatrin: placental transfer in vivo and excretion into breast milk of the enantiomers. Br J Clin Pharmacol 1998; 45:409-11. [PMID: 9578192 PMCID: PMC1873959 DOI: 10.1046/j.1365-2125.1998.t01-1-00693.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AIMS Vigabatrin is a new antiepileptic medication consisting of a racemic mixture of 50% active S enantiomer and 50% inactive R enantiomer. Since patients suffering from epilepsy may become pregnant, it is important to understand the extent of placental transfer of such medication. METHODS During steady-state, vigabatrin enantiomer concentrations were measured in maternal and umbilical blood and in breast milk of two patients. RESULTS The concentration ratios from the umbilical vein to maternal plasma were R:0.068, S:0.16; 4h25 min after drug administration (case 1) and R: 1.39, S: 0.91; 9h after drug administration (case 2). The milk: plasma concentration ratio was lower than 1 at pre dose sampling in both cases, as well as 3 and 6 h post dose in one case. An estimate of the maximum amount of R and S enantiomers of vigabatrin that a suckling infant would ingest in a day is 3.6% and 1% of the weight-adjusted daily dose respectively. CONCLUSIONS These results would suggest a slow placental transfer of the vigabatrin enantiomers and that the quantity ingested through milk is small.
Collapse
|
research-article |
27 |
21 |
24
|
Daugbjerg P, Brems M, Mai J, Ankerhus J, Knudsen FU. Intermittent prophylaxis in febrile convulsions: diazepam or valproic acid? Acta Neurol Scand 1990; 82:17-20. [PMID: 2239131 DOI: 10.1111/j.1600-0404.1990.tb01581.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In an open, prospective, randomized, and hospital-based study, comprising 219 consecutive children, 169 were given intermittent prophylaxis for one year, receiving either diazepam or valproic acid after their first febrile convulsion. Children admitted on odd dates (n = 89) were given rectal diazepam in solution every 12 h, whenever the temperature was 38.5 degrees C or more. Children admitted on even dates (n = 80) were given valproic acid as suppositories at times of fever. Twenty-three children in the diazepam group had a recurrence within 1 year versus 14 in the valproic acid group. On an intention-to-treat basis the 12-month recurrence rates in the 2 groups were similar, 27% vs 20%. The latter is well below figures for untreated controls from Denmark (32%), suggesting that intermittent valproic acid at times of fever may be effective, but further studies are needed. The number of complex recurrences, however, were significantly higher in the valproic acid group than in the diazepam group. Parental non-compliance was a major problem, and in the 2 study groups only 5 and 12 children, respectively, with recurrences were treated adequately. Sixty-nine children receiving diazepam had side-effects vs 37 receiving valproic acid. None were serious.
Collapse
|
Clinical Trial |
35 |
19 |
25
|
Yu PH, Mai J, Kinsella JE. The effects of dietary trans, trans methyl octadecadienoate acid on composition and fatty acids of rat heart. Am J Clin Nutr 1980; 33:598-605. [PMID: 7355844 DOI: 10.1093/ajcn/33.3.598] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
|
|
45 |
19 |