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Houweling M, Cui Z, Anfuso CD, Bussière M, Chen MH, Vance DE. CTP: phosphocholine cytidylyltransferase is both a nuclear and cytoplasmic protein in primary hepatocytes. Eur J Cell Biol 1996; 69:55-63. [PMID: 8825024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
CTP:phosphocholine cytidylyltransferase (CT) has recently been reported to be a predominantly intranuclear enzyme in several cell lines (Wang et al., J. Biol. Chem. 268, 5899-5904 (1993)). This contrasts with previous reports that CT was a cytosolic protein that translocated to the endoplasmic reticulum upon activation. The aim of the present study was to compare the localization of CT in CHO cells and in primary rat hepatocytes. Indirect immunofluorescence of CHO cells revealed a largely nuclear localization of the CT. On the other hand, immunogold electron microscopy and biochemical studies showed a similar density of distribution of CT between the nucleus and cytoplasm. In primary rat hepatocytes immunofluorescence studies indicated that CT was largely cytoplasmic. Studies by immunogold electron microscopy of rat hepatocytes demonstrated that the enzyme was homogeneously distributed throughout all cytoplasmic regions and the nucleoplasm. This result was confirmed by biochemical studies using digitonin and streptolysin O, which permeabilizes the plasma membrane of cells. Enucleation studies indicated that in CHO cells 76% of the CT activity was in the nuclear fraction, whereas in hepatocytes only 32% was recovered in this fraction. The data indicate that CT is found both in nuclear and cytoplasmic fractions of primary hepatocytes and is not predominantly a nuclear enzyme.
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Tsai CM, Chang KT, Wu LH, Chen JY, Gazdar AF, Mitsudomi T, Chen MH, Perng RP. Correlations between intrinsic chemoresistance and HER-2/neu gene expression, p53 gene mutations, and cell proliferation characteristics in non-small cell lung cancer cell lines. Cancer Res 1996; 56:206-9. [PMID: 8548764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Using a panel of 20 non-small cell lung cancer (NSCLC) cell lines established from previously untreated patients, we investigated the relationships between intrinsic chemoresistance (to four agents used commonly in the therapy of NSCLC) and HER-2/neu gene expression (which encodes glycoprotein p185neu), p53 gene mutations, and cell proliferation characteristics. Our results demonstrated that high p185neu expression was correlated with chemoresistance, low S-phase fractions, and long doubling times. By contrast, cell lines expressing relatively low levels of p185neu were relatively chemosensitive and had higher S-phase fractions and shorter doubling times. Although mutation of the p53 gene was a common event in this panel of cell lines (present in 18 of 20 lines), there was no relationship between mutations at any specific codon and chemoresistance or cell proliferation characteristics. Multivariate analysis revealed that the level of p185neu was the only independent predictor for chemoresistance to doxorubicin, etoposide, and probably cisplatin. Although intrinsic chemoresistance almost certainly is a multifactorial process, overexpression of p185neu may be an important factor in the chemoresistance of NSCLC.
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Wu SH, Huang HT, Lin CF, Chen MH. Effects of a program on symmetrical posture in patients with hemiplegia: A single-subject design. Am J Occup Ther 1996; 50:17-23. [PMID: 8644832 DOI: 10.5014/ajot.50.1.17] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
OBJECTIVES Asymmetrical posture during static stance has been identified as a common problem in persons with hemiplegia. This study examined the effect of an activity-based therapy regimen on symmetric weight bearing and midline position of center of gravity (COG) in three adult subjects with hemiplegia. METHOD An ABAB single-subject design was used. The intervention program, including sanding in front of a standing table and play a bean bag game, was introduced for 30 min each day during each intervention phase. Quantitative measurements of the weight distribution and the midline position of COG were taken with the Balance Master System (version 2.20). RESULTS Visual inspection and statistical analysis of the data revealed a significant improvement in symmetric weight distribution and midline position of COG. The study suggests that this program may be a promising alternative to a variety of postural rehabilitation programs for persons with hemiplegia. CONCLUSION Insecurity caused by poor stabilization and abnormal reactions to body weight bearing in an antigravity position might contribute to asymmetric postures. Results of this study suggest that an activity-oriented program can be effective in helping the persons with hemiplegia achieve symmetric stances.
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Chen MH, Shen ZM, Bobin S, Kahn PC, Lipke PN. Structure of Saccharomyces cerevisiae alpha-agglutinin. Evidence for a yeast cell wall protein with multiple immunoglobulin-like domains with atypical disulfides. J Biol Chem 1995; 270:26168-77. [PMID: 7592821 DOI: 10.1074/jbc.270.44.26168] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
alpha-Agglutinin of Saccharomyces cerevisiae is a cell wall-associated protein that mediates cell interaction in mating. Although the mature protein includes about 610 residues, the NH2-terminal half of the protein is sufficient for binding to its ligand a-agglutinin. alpha-Agglutinin20-351, a fully active fragment of the protein, has been purified and analyzed. Circular dichroism spectroscopy, together with sequence alignments, suggest that alpha-agglutinin20-351 consists of three immunoglobulin variable-like domains: domain I, residues 20-104; domain II, residues 105-199; and domain III, residues 200-326. Peptide sequencing data established the arrangement of the disulfide bonds in alpha-agglutinin20-351. Cys97 is disulfide-bonded to Cys114, forming an interdomain bond between domains I and II. Cys202 is bonded to Cys300, in an atypical intradomain disulfide bond between the A and F strands of domain III. Cys227 and Cys256 have free sulfhydryls. Sequencing also showed that at least two of three potential N-glycosylation sites with sequence Asn-Xaa-Thr are glycosylated. At least one of three Asn-Xaa-Ser sequences is not glycosylated. No residues NH2-terminal to Ser282 were O-glycosylated, whereas Ser282, and all hydroxy amino acid residues COOH-terminal to this position were modified. Therefore O-glycosylated Ser and Thr residues cluster in the COOH-terminal region of domain III, and the O-glycosylation continues into a Ser/Thr-rich sequence that extends from domain III to the COOH-terminal of the full-length protein.
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Chen MH, Osterheld AL. Effects of autoionizing resonances on electron-impact excitation rates and gain calculations for Ni-like tantalum. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1995; 52:3790-3795. [PMID: 9912685 DOI: 10.1103/physreva.52.3790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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181
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Beiersdorfer P, Osterheld A, Elliott SR, Chen MH, Knapp D, Reed K. Structure and Lamb shift of 2s1/2-2p3/2 levels in lithiumlike Th87+ through neonlike Th80+. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1995; 52:2693-2706. [PMID: 9912551 DOI: 10.1103/physreva.52.2693] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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182
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Chen MH, Reed KJ, McWilliams DM. Resonant effects on electron-impact ionization of sodiumlike selenium. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1995; 52:2881-2884. [PMID: 9912572 DOI: 10.1103/physreva.52.2881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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183
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Lipke PN, Chen MH, de Nobel H, Kurjan J, Kahn PC. Homology modeling of an immunoglobulin-like domain in the Saccharomyces cerevisiae adhesion protein alpha-agglutinin. Protein Sci 1995; 4:2168-78. [PMID: 8535254 PMCID: PMC2142996 DOI: 10.1002/pro.5560041023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The Saccharomyces cerevisiae adhesion protein alpha-agglutinin is expressed by cells of alpha mating type. On the basis of sequence similarities, alpha-agglutinin has been proposed to contain variable-type immunoglobulin-like (IgV) domains. The low level of sequence similarity to IgV domains of known structure made homology modeling using standard sequence-based alignment algorithms impossible. We have therefore developed a secondary structure-based method that allowed homology modeling of alpha-aggulutinin domain III, the domain most similar to IgV domains. The model was assessed and where necessary refined to accommodate information obtained by biochemical and molecular genetic approaches, including the positions of a disulfide bond, glycosylation sites, and proteolytic sites. The model successfully predicted surface exposure of glycosylation and proteolytic sites, as well as identifying residues essential for binding activity. One side of the domain was predicted to be covered by carbohydrate residues. Surface accessibility and volume packing analyses showed that the regions of the model that have greatest sequence dissimilarity from the IgV consensus sequence are poorly structured in the biophysical sense. Nonetheless, the utility of the model suggests that these alignment and testing techniques should be of general use for building and testing of models of proteins that share limited sequence similarity with known structures.
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184
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Chen MH, Scofield JH. Relativistic effects on angular distribution and polarization of dielectronic satellite lines of hydrogenlike ions. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1995; 52:2057-2061. [PMID: 9912464 DOI: 10.1103/physreva.52.2057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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185
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Chan PD, Findlay JM, Vollrath B, Cook DA, Grace M, Chen MH, Ashforth RA. Pharmacological and morphological effects of in vitro transluminal balloon angioplasty on normal and vasospastic canine basilar arteries. J Neurosurg 1995; 83:522-30. [PMID: 7666232 DOI: 10.3171/jns.1995.83.3.0522] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Despite growing clinical use of transluminal balloon angioplasty (TBA) to treat cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH), the precise mechanism of action of balloon dilation on the cerebral arterial wall is unknown. In this experiment the authors examined the pharmacological and morphological changes in 10 normal and 12 vasospastic canine basilar arteries following in vitro silicone microballoon TBA. For the SAH group in which the double-hemorrhage model was used, vasospasm was confirmed by angiography and the animals were killed on Day 7 after the first SAH. In vitro TBA was performed on basilar arteries from normal and SAH dogs immediately after sacrifice and removal of the brain. The procedure was performed while the arteries were maintained in oxygenated Krebs buffer. In the pharmacological studies, potassium chloride, prostaglandin F2 alpha, serotonin, and noradrenaline were used as vasoconstrictors, and bradykinin and calcium ionophore A23187 were used to produce an endothelium-dependent dilation. In both normal and vasospastic groups, the pharmacological responses of dilated segments of basilar arteries were compared to those of nondilated segments of the same arteries. Vessels from all groups were examined using scanning electron microscopy (EM) and transmission EM. Scanning EM was used to study the intact vessel wall, the smooth-muscle cell layer obtained after digestion with hydrochloric acid, and the extracellular matrix obtained after digestion with bleach. Cross-sections of the vessel wall were examined using transmission EM. The most striking finding was that immediately after in vitro TBA of both normal and vasospastic canine basilar arteries, there was a significant reduction (p < 0.05) of responses to both vasoconstrictors and vasorelaxants. As revealed by scanning EM and transmission EM, both normal and vasospastic vessels dilated with TBA showed flattening and patchy denudation of the endothelium, and straightening and occasional rupturing of the internal elastic lamina. In addition, vasospastic vessels dilated with TBA showed decreased surface rippling and mild stretching and straightening of smooth-muscle cells, and mild thinning of the tunica media. There was no gross vascular disruption or obvious change in the extracellular matrix of the vessel walls of either normal or vasospastic arteries after TBA. These results suggest that functional impairment of vasoreactivity in the vessel wall as a result of mechanical stretching of the smooth-muscle layer plays a more important role than structural alteration, at least in the immediate dilation produced in vasospastic arteries by TBA.
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MESH Headings
- Analysis of Variance
- Angioplasty, Balloon
- Animals
- Basilar Artery/drug effects
- Basilar Artery/physiopathology
- Basilar Artery/ultrastructure
- Bradykinin/pharmacology
- Calcimycin/pharmacology
- Collagen/ultrastructure
- Dinoprost/pharmacology
- Dogs
- Dose-Response Relationship, Drug
- Elastin/ultrastructure
- Endothelium, Vascular/ultrastructure
- In Vitro Techniques
- Ischemic Attack, Transient/diagnostic imaging
- Ischemic Attack, Transient/etiology
- Ischemic Attack, Transient/therapy
- Microscopy, Electron
- Microscopy, Electron, Scanning
- Muscle, Smooth, Vascular/ultrastructure
- Norepinephrine/pharmacology
- Potassium Chloride/pharmacology
- Radiography
- Serotonin/pharmacology
- Subarachnoid Hemorrhage/complications
- Vasoconstriction/drug effects
- Vasodilation/drug effects
- Vasodilation/physiology
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Chen C, Li L, Chen LL, Prada JV, Chen MH, Fallon JT, Weyman AE, Waters D, Gillam L. Incremental doses of dobutamine induce a biphasic response in dysfunctional left ventricular regions subtending coronary stenoses. Circulation 1995; 92:756-66. [PMID: 7641353 DOI: 10.1161/01.cir.92.4.756] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Dobutamine stress echocardiography has been proposed as a diagnostic tool to identify viable myocardium. How regional wall thickening responds to dobutamine in the ischemic or short-term hibernating myocardium has not been adequately defined. We hypothesized that regional wall thickening would improve initially and subsequently deteriorate with incremental doses of dobutamine in viable myocardial regions supplied by a stenotic coronary artery. This study was undertaken to determine whether this biphasic pattern of regional function characterizes the response of ischemic or hibernating myocardium to dobutamine and to explore the factors and mechanisms that determine this response. METHODS AND RESULTS Twenty-six pigs in four groups were studied: a control group (n = 5) to assess the response of myocardium perfused by nonstenotic coronary artery to incremental doses of dobutamine, and three experimental groups with a left anterior descending coronary artery stenosis producing acute myocardial ischemia (n = 7), short-term myocardial hibernation for 90 minutes (n = 7), and short-term hibernation for 24 hours (n = 7) to determine the functional and metabolic response to dobutamine under these conditions. Regional coronary flow was reduced to 40% to 60% of baseline, with significant reductions of regional wall thickening as measured by two-dimensional echocardiography and sonomicrometers. An incremental dobutamine infusion from 2.5 to 25 micrograms.kg-1.min-1 increased wall thickening and coronary flow without lactate production in the control group. In the other three groups, during the incremental dobutamine infusion, regional wall thickening improved initially, from 11.4 +/- 7.5% to 19.8 +/- 11.4%, P < .01, at dobutamine doses of 2.5 to 10 (4.5 +/- 2.2) micrograms.min-1.kg-1 but deteriorated subsequently to 5.0 +/- 5.8% at the maximal dose of dobutamine of 12.6 +/- 4.1 micrograms.min-1.kg-1. The initial improvement of regional wall thickening was associated with a small increase in regional coronary flow (from 0.53 +/- 0.18 to 0.68 +/- 0.25 mL.min-1.g-1 myocardium, P < .05) and with regional lactate production. High doses of dobutamine did not further increase regional coronary flow but markedly increased lactate production and induced regional myocardial acidosis (pH 7.26 +/- 0.07). The biphasic pattern of response to dobutamine was observed in each of the three experimental groups. Both peak improvement and peak deterioration occurred earlier and at lower dobutamine dose levels in the group with acute ischemia compared with the group with short-term hibernation for 24 hours (P < .05). CONCLUSIONS A biphasic response of wall thickening to incremental dobutamine with initial improvement and subsequent deterioration is characteristic of ischemic or short-term hibernating myocardium. The initial low-dose dobutamine infusion improved wall thickening in the ischemic or hibernating myocardial region to a modest level. This initial modest improvement was transient and at the expense of metabolic deterioration of myocardial ischemia, so that at higher doses during prolonged dobutamine infusion, wall thickening deteriorated, lactate accumulated, and myocardial acidosis developed.
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187
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Chen MH, Murphy EA, Halpern V, Faust GR, Cosgrove JM, Cohen JR. Laparoscopic-assisted abdominal aortic aneurysm repair. Surg Endosc 1995; 9:905-7. [PMID: 8525445 DOI: 10.1007/bf00768889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Since the advent of laparoscopy, the sweeping changes seen in general surgery have not been paralleled in vascular surgery. There have been case reports of laparoscopic-assisted aortobifemoral bypass for occlusive disease. Because aneurysmal disease comprises the majority of aortic surgery, we pursued animal and cadaveric feasibility studies for laparoscopic-assisted abdominal aortic aneurysm (AAA) repair. We present a case report of the first clinical case performed under Institutional Review Board protocol using this technique. The patient was a 62-year-old male with a 6-cm infrarenal AAA. After obtaining a pneumoperitoneum, a modified fish retractor was used to exclude the bowel. Ten 11-mm ports provided access to laparoscopically dissect the neck of the aneurysm and the iliac vessels. Then, a 10-cm minilaparotomy was performed and standard vascular clamps were inserted via the port incisions. Standard aneurysmorraphy was performed with a polytetrafluoroethylene (PTFE) tube graft. Laparoscopy conferred three major benefits: better visualization of the aneurysm neck, less bowel manipulation, and avoidance of hypothermia. This case report illustrates the feasibility of laparoscopic-assisted aneurysm repair. Controlled human studies will define the role of laparoscopy in AAA surgery.
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188
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Vazquez de Prada JA, Jiang L, Chen MH, Padial LR, Guerrero JL, Schwammenthal E, King ME, Weyman AE, Chen C, Levine RA. Intracardiac ultrasonographic assessment of atrial septal defect area: in vitro validation and technical considerations. Am Heart J 1995; 130:302-6. [PMID: 7631611 DOI: 10.1016/0002-8703(95)90444-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Assessment of atrial septal defect (ASD) size and shape is important for planning and guiding its transcatheter occlusion and can potentially be achieved by intracardiac ultrasonography (ICUS). ICUS accuracy, however, must first be established against stable standards and technical imaging requirements defined. We therefore used 10, 20, and 30 MHz ICUS catheters to examine 17 ASDs that were 0.16 to 6.7 cm2 in area and were surgically created in excised ovine hearts with 10, 20, and 30 MHz ICUS catheters. ASD shape and area by ICUS were compared with direct video images of the actual ASD. In all instances minimal area by ICUS pullback agreed well with actual values (y = 1.04x + 0.2, SEE = 0.23 cm2, r = 0.99) and corresponded well with defect shapes. The maximum angle between ultrasonography beam and septal plane allowing for complete ASD visualization was 20 degrees. The angle depended on transducer frequency and septal thickness. This new technique has potential value for the accurate assessment of ASD shape and size and may be especially useful in the setting of transcatheter occlusion.
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189
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Patchett AA, Nargund RP, Tata JR, Chen MH, Barakat KJ, Johnston DB, Cheng K, Chan WW, Butler B, Hickey G. Design and biological activities of L-163,191 (MK-0677): a potent, orally active growth hormone secretagogue. Proc Natl Acad Sci U S A 1995; 92:7001-5. [PMID: 7624358 PMCID: PMC41459 DOI: 10.1073/pnas.92.15.7001] [Citation(s) in RCA: 245] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A potent, orally active growth hormone (GH) secretagogue L-163,191 belonging to a recently synthesized structural class has been characterized. L-163,191 releases GH from rat pituitary cells in culture with EC50 = 1.3 +/- 0.09 nM and is mechanistically indistinguishable from the GH-releasing peptide GHRP-6 and the prototypical nonpeptide GH secretagogue L-692,429 but clearly distinguishable from the natural GH secretagogue, GH-releasing hormone. L-163,191 elevates GH in dogs after oral doses as low as 0.125 mg/kg and was shown to be specific in its release of GH without significant effect on plasma levels of aldosterone, luteinizing hormone, thyroxine, and prolactin after oral administration of 1 mg/kg. Only modest increases in cortisol were observed. Based on these properties, L-163,191 has been selected for clinical studies.
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190
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Chen MH, Cheng KT, Johnson WR, Sapirstein J. Relativistic configuration-interaction calculations for the n=2 states of lithiumlike ions. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1995; 52:266-273. [PMID: 9912244 DOI: 10.1103/physreva.52.266] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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191
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Hu PJ, Li YY, Lin HL, Zhou SM, Du G, Chen MH, Mitchell HM, Hazell SL. Gastric atrophy and regional variation in upper gastrointestinal disease. Am J Gastroenterol 1995; 90:1102-6. [PMID: 7611205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To compare the upper gastrointestinal disease profiles of Helicobacter pylori-infected patients drawn from two distinct regions of China, one with a low incidence of gastric cancer (Guangzhou) and the other with a high incidence of gastric cancer (Lanzhou). The age-standardized prevalence of H. pylori within the populations of these two cities was similar (approximately 56%). In these patient groups, the prevalence of different gastrointestinal disease states and the occurrence and severity of gastritis, gastric atrophy, and intestinal metaplasia were compared. METHODS This study was based on consecutive patients: 265 from Guangzhou and 275 from Lanzhou. The grading of gastritis and the detection of H. pylori was determined by histology using the "Sydney System". RESULTS The ratio of cases of duodenal to gastric ulceration for the two cities was: Guangzhou 14:1 and Lanzhou 3:1. Gastric cancer was more prevalent in the patients from Lanzhou (9.8%) than from Guangzhou (3%). In nonulcer dyspepsia patients from Guangzhou, gastritis was predominantly antral, whereas, in Lanzhou, gastritis was predominantly uniform. The amount and severity of atrophy was significantly greater in Lanzhou compared with Guangzhou. CONCLUSIONS The prevalence of atrophy, rather than age of acquisition and prevalence of H. pylori infection, appears to be a marker of the major upper gastrointestinal disease profiles of a region. Development of atrophy, although apparently related to H. pylori infection, may be a multifactorial condition. Differences in diet, as seen between Guangzhou and Lanzhou, may be important in this regard. Understanding the factors leading to the development of atrophy may enhance our understanding of processes leading to gastric malignancy.
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192
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Pindzola MS, Robicheaux FJ, Badnell NR, Chen MH, Zimmermann M. Photorecombination of highly charged uranium ions. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1995; 52:420-425. [PMID: 9912264 DOI: 10.1103/physreva.52.420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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193
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Tsay TP, Chen MH, Oyen OJ, Hahn SS, Marty JJ. The effect of cobalt-60 irradiation on bone marrow cellularity and alveolar osteoclasts. PROCEEDINGS OF THE NATIONAL SCIENCE COUNCIL, REPUBLIC OF CHINA. PART B, LIFE SCIENCES 1995; 19:185-95. [PMID: 7480365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The purpose of this study was to investigate the mechanisms of bone resorption in the rat dentoalveolar complex occurring as a result of orthodontic appliance therapy. Utilizing whole body radioactive cobalt 60 (Co60) irradiation in combination with orthodontic tooth movement, the activation, recruitment, and life span of osteoclasts was studied. Thirty-four adult Fischer 344 rats were irradiated with 10 and 20 Gray of Co60. Twelve days after irradiation, each rat was fitted with an orthodontic appliance; the rats were sacrificed 7, 14, or 21 days after appliance placement. To serve as controls, another group of 12 rats was subjected to orthodontic treatment only. Histologic sections were prepared from decalcified maxillary alveolar process, and osteoclasts were counted. In the control group, osteoclasts were presence in the periodontal membrane for four weeks after appliance placement, and the largest number of osteoclasts was observed in the second week. The smaller total irradiation dose (10 Gray, administered in 5 daily fractions) induced a transient reduction in the bone marrow cell count of more than 90%, followed by a complete rebound. The peak osteoclst number also was increased 110%. In contrast, the higher total dose (20 Gray, administered in 10 daily fractions) resulted in a reduction of 60% in bone marrow cellularity and a decrease in the peak osteoclast number by 40%. Fluctuations in bone marrow cellularity generally corresponded to similar variations in the osteoclast number, but there was an apparent lack of correspondence between bone marrow cell and white blood cell values. The total period of osteoclastic presence in the periodontal membrane following orthodontic activation, normally four weeks in duration, was reduced by one week in the irradiated animals. These findings lead us to speculate that the mechanisms of osteoclast activation and recruitment following orthodontic appliance therapy may involve three consecutive waves of osteoclast maturation. The total duration of osteoclastic bone resorption lasts 4 weeks, but the osteoclast lie span is calculated to be 9 to 10 days (9 days x 3 waves = 27 days). If the results of this study are proved to be reproducible, a scientific basis may have been provided to support the common practice in orthodontics wherein the duration between orthodontic appointments is 4-5 weeks.
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194
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Huang SC, Lin WW, Chen MH. Time-division multiplexing of polarization-insensitive fiber-optic Michelson interferometric sensors. OPTICS LETTERS 1995; 20:1244-1246. [PMID: 19859487 DOI: 10.1364/ol.20.001244] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A system of time-division multiplexing of polarization-insensitive fiber-optic Michelson interferometric sensors that uses Faraday rotator mirror elements is demonstrated. This system is constructed with conventional low-birefringence single-mode fiber and is able to solve the polarization-fading problem by a combination of Faraday rotator mirrors with unbalanced Michelson interferometers. The system is lead-fiber insensitive and has potentials for practical field applications.
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195
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Padial LR, Chen MH, Vuille C, Guerrero JL, Weyman AE, Picard MH. Pulsatile pressure affects the disappearance of echocardiographic contrast agents. J Am Soc Echocardiogr 1995; 8:285-92. [PMID: 7640022 DOI: 10.1016/s0894-7317(05)80039-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The purpose of this study was to determine in an in vitro model the effect of pulsatile pressure on the decay of echocardiographic contrast agents. Use of contrast agents for quantitative assessment of perfusion requires understanding of the factors controlling their rates of disappearance. Prior studies have shown that constant pressure affects the rate of disappearance of these agents. It is not known whether pulsatile pressure influences the rate of decay of contrast agents. In an in vitro chamber, three contrast agents (Albunex, hand-agitated saline solution, and hand-agitated Angiovist) were exposed to pulses of pressure at three rates (30, 60, and 120 pulsations/min), keeping pressure characteristics (peak, nadir, and mean) within a narrow range. Five injections were performed for each agent at each rate. Two-dimensional echocardiographic images of the effects of contrast material were recorded from injection until total disappearance. Videointensity was measured and time-intensity curves were generated. These curves of intensity decay were fitted to an exponential decay function (I = Ae-lambda t) and the velocity of decay (lambda) was used for comparisons. For all agents, intensity of contrast decreased over time. Saline solution and Angiovist, but not Albunex, showed pulsatile decreases in intensity of contrast with each peak pressure and partial recovery of contrast intensity with each nadir pressure. (ABSTRACT TRUNCATED AT 250 WORDS)
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196
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Zou YL, Zhang JD, Chen MH, Shi GQ, Cocito C. Comparative cutaneous testing with purified protein derivative and the antigen complex A60 in vaccinated subjects and tuberculosis patients. Med Microbiol Immunol 1995; 184:9-15. [PMID: 8538579 DOI: 10.1007/bf00216784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Some 840 bacille Calmette-Guérin (BCG)-vaccinated healthy controls and tuberculosis patients from two Chinese hospitals were submitted to comparative skin tests with purified protein derivative of tuberculin (PPD; as reference) and with the antigen complex A60 from Mycobacterium bovis BCG. In a first trial, including 581 persons (185 healthy juveniles, 180 healthy adults and 216 tuberculosis patients), a limited dose of A60 (1 microgram) was used. Performance of the A60 test was similar to that of 5 I.U. PPD for controls (cut-off values = 5 mm induration diameter), but lower than that seen for tuberculosis patients (10 mm cut-off values). A second survey was conducted on 259 persons (109 recently revaccinated healthy persons, considered as tuberculin-negative in the first trial, and 150 tuberculosis patients), using a higher dose of A60 (2 micrograms) and the same dose of PPD (5 I.U.). Similar results were obtained with the two tests in all cases, thus supporting the possibility of PPD replacement by A60 in cutaneous testing. The pattern of induration diameter distribution in healthy subjects who took part in the first testing round (64% positively rate) was displaced to the inactivity side (with a peak at 5 to 9-mm diameter), in comparison with the second round (90% positivity rate and peak at 10-14 mm). This indicates a progressive fading of cellular immunity reactions after BCG vaccination. In tuberculosis patients, no correlation was found among the following three parameters: positivity at cutaneous testing (with PPD or A60), titer of anti-A60 mycobacterial immunoglobulins in blood (IgG titer higher than cut-off line) and presence of mycobacteria in sputum.
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Hendel RC, Chen MH, L'Italien GJ, Newell JB, Paul SD, Eagle KA, Leppo JA. Sex differences in perioperative and long-term cardiac event-free survival in vascular surgery patients. An analysis of clinical and scintigraphic variables. Circulation 1995; 91:1044-51. [PMID: 7850940 DOI: 10.1161/01.cir.91.4.1044] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Little information is available regarding the occurrence of perioperative and late cardiac events in women with vascular disease. The current study was performed to examine whether sex-specific differences exist in these outcomes in a large population of vascular surgery patients and to determine the value of clinical and dipyridamole thallium variables in predicting myocardial infarction and cardiac death. METHODS AND RESULTS Preoperative dipyridamole thallium imaging was performed in 567 vascular surgery patients, including 380 men and 187 women. The incidence of nonfatal myocardial infarction and cardiac death was noted during the perioperative period and during a follow-up period of 50 +/- 5 months. Fixed and reversible thallium perfusion abnormalities were more common in men than in women (P < .001 and P = .004, respectively). Perioperative cardiac event rates were similar in men and women, 8.4% and 7.5%, respectively (P = .07). A transient thallium defect was associated with an increased risk of cardiac events by 3.9-fold in men (CI, 1.5 to 10.2) and 5.5-fold in women (CI, 1.4 to 22). Various clinical factors also were predictive of events but demonstrated substantial sex differences. For example, dipyridamole-induced ST-segment depression was strongly associated with perioperative events in men but not in women. There were 22 nonfatal myocardial infarctions and 29 cardiac deaths in men during the follow-up period, with comparable event rates noted for women. Cardiac event-free survival rates also were similar for men and women (P = .40). Multivariate analysis demonstrated that a history of heart failure was an important prognostic variable for both sexes, as was a fixed thallium defect. Significant sex differences in the predictive value of other clinical factors for late cardiac events was apparent. CONCLUSIONS The present study demonstrates that (1) thallium perfusion defects are more common in men; (2) transient thallium defects are associated with perioperative myocardial infarction and cardiac death in both sexes; (3) long-term survival rates after vascular surgery are similar between men and women; (4) a fixed perfusion defect is predictive of late cardiac events in women, with a trend noted in men; and (5) sex-specific differences were noted with regard to the prognostic value of various clinical risk factors. Therefore, dipyridamole thallium plays a significant role in the assessment of perioperative and long-term prognosis for both male and female vascular surgery patients. On the basis of these observations, modifications in risk stratification based on sex may be appropriate for men and women with vascular disease.
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Hu PJ, Li YY, Zhou MH, Chen MH, Du GG, Huang BJ, Mitchell HM, Hazell SL. Helicobacter pylori associated with a high prevalence of duodenal ulcer disease and a low prevalence of gastric cancer in a developing nation. Gut 1995; 36:198-202. [PMID: 7883217 PMCID: PMC1382404 DOI: 10.1136/gut.36.2.198] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This study examines the relationship between Helicobacter pylori infection and peptic ulcer disease and gastric cancer--in particular, the presence or absence of bacteria, the grading of gastritis, and the degree of inflammation in the antral and oxyntic mucosae. The grading of gastritis and the detection of H pylori were determined by histology using the Sydney system. Of the 1006 patients examined, 34.5% had duodenal ulcer disease, 3.5% gastric ulcer disease, and 2% with coexistent ulceration. Most patients (50.2%) were classified as having non-ulcer dyspepsia. Altogether 2.4% of patients had gastric cancer and two further patients had carcinoma in the gastric stump. Of the ulcer disease patients, 87.2% had histological evidence of H pylori infection. After patients who had taken antibiotics or bismuth compounds in the preceding four weeks were excluded, 98.9% of the duodenal ulcer disease, 100% of the gastric ulcer disease, and 100% of the coexistent ulcer disease patients had evidence of H pylori infection. In patients with gastric cancer who had not taken antimicrobial agents in the four weeks before endoscopy, 83.3% had evidence of H pylori infection. Thus, there was a high rate of duodenal ulcer disease and a low rate of gastric ulcer disease in southern China, an area of low gastric cancer mortality. There was a specific topographical relationship between H pylori, the histological response, and gastroduodenal disease. Our data suggest that the status of a nation as either 'developed' or 'developing' can not be used to predict the upper gastrointestinal disease profile of its population.
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Knapp DA, Beiersdorfer P, Chen MH, Scofield JH, Schneider D. Observation of interference between dielectronic recombination and radiative recombination in highly charged uranium ions. PHYSICAL REVIEW LETTERS 1995; 74:54-57. [PMID: 10057697 DOI: 10.1103/physrevlett.74.54] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Zou YL, Zhang JD, Chen MH, Shi GQ, Prignot J, Cocito C. Serological analysis of pulmonary and extrapulmonary tuberculosis with enzyme-linked immunosorbent assays for anti-A60 immunoglobulins. Clin Infect Dis 1994; 19:1084-91. [PMID: 7888538 DOI: 10.1093/clinids/19.6.1084] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
IgA, IgG, and IgM antibodies to mycobacterial antigen A60 were measured by ELISA in blood, pleural fluid, and cerebrospinal fluid from 560 patients with pulmonary and/or extrapulmonary tuberculosis who were being treated at hospitals in northern China and from 734 uninfected controls. Among 529 healthy persons (most of whom had been vaccinated with bacille Calmette-Guérin [BCG] and 287 of whom were tuberculin-positive), the rate of false-positive results was negligible; this observation ruled out interference of remote BCG vaccination with A60 assays at the chosen cutoff level. Rates of positivity for IgM and IgG, respectively, were 80% and 36% among patients with active primary pulmonary tuberculosis, 31% and 88.5% among patients with active postprimary pulmonary tuberculosis, 0 and 41% among patients with inactive pulmonary tuberculosis, and 30%-61% and 69%-86% among patients with extrapulmonary tuberculosis. Paired samples of blood and pleural fluid from patients with pleurisy contained IgA antibody to A60 at equal titers; in contrast, most patients with tuberculous meningitis (100% of whom had a positive ELISA result) had higher levels of IgG antibody to A60 in cerebrospinal fluid than in blood--proof of intrathecal synthesis.
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