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Yang SS, Wong P, Ma S, Cooks RG. SiCl 3 (+) and SiCl (+) affinities for pyridines determined by using the kinetic method with multiple stage mass spectrometry: Agostic effects in the gas phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1996; 7:198-204. [PMID: 24203242 DOI: 10.1016/1044-0305(95)00630-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/1995] [Revised: 09/07/1995] [Accepted: 09/07/1995] [Indexed: 06/02/2023]
Abstract
Cluster ions, Py1SiCl 3 (+) Py2 and Py1SiCl(+)Py2, where Py1 and Py2 represent substituted pyridines, formed upon reactive collisions of mass-selected SiCl 3 (+) or SiCl(+) cations with a mixture of pyridines, are shown to have loosely bound structures by multiple stage mass spectrometry experiments in a pentaquadrupole mass spectrometer. The fragment ion abundance ratio, ln([Py1SiCl n (+) ]/[Py2SiCl n (+) ]) (n=1 or 3) is used to estimate the relative SiCl 3 (+) or SiCl(+) affinities of the constituent pyridines by the kinetic method. In the case of clusters comprised of meta- and/or para-substituted pyridines (unhindered pyridines), the SiCl 3 (+) and SiCl(+) affinities are shown to display excellent linear correlations with the proton affinities (PAs). On the assumption that the effective temperatures of the SiCl 3 (+) - and SiCl(+)-bound dimers are 555 K (i. e., the same as those of the corresponding Cl(+)-bound dimers), SiCl 3 (+) and SiCl(+) affinities of the substituted pyridines, relative to pyridine, are estimated to be 3-MePy (2.1 kcal/mol), 4-MePy (3.2 kcal/mol), 3-EtPy (3.7 kcal/mol), 4-EtPy (4.2 kcal/mol), 3,5-diMePy (4.8 kcal/mol), and 3,4-diMePy (5.4 kcal/mol). The SiCl 3 (+) and SiCl(+) cation affinities are related to the proton affinities by the expressions: relative (SiCl 3 (+) ) affinity = 0.95 ΔPA and relative (SiCl(+)) affinity = 0.60 ΔPA. The smaller constant in the relationship between the relative SiCl affinity and the relative proton affinity is the result of weaker bonding.Steric effects between the ortho-substituted alkyl group and the central SiCl 3 (+) cation reduce the SiCl 3 (+) affinities of dimers that contain ortho-substituted pyridines. The magnitude of the steric acceleration of fragmentation is used to measure a set of gas-phase steric parameters (S (k)). The steric effects in the SiCl 3 (+) dimers are similar in magnitude to those in the corresponding Cl(+)-bound dimers but weaker than those produced by the bulky [OCNCO](+) group. An inverted steric effect is observed in those SiCl(+)-bound dimers that incorporate ortho-substituted pyridines and is ascribed to auxiliary Si-H-C bonding, which stabilizes the ortho-substituted pyridine-SiCl(+) bond. This auxiliary bonding appears to correspond to agostic bonding, which is well characterized in solution and occurs in competition with steric effects that weaken the pyridine-SiCl(+) interaction.Ion-molecule reactions of pyridines with halosilicon radical cations SiCl 2 (+) and SiCl 4 (+) as well as alkylated halosilicon cations Si(CH3)2Cl(+) and Si(CH3)Cl 2 (+) also are investigated. In these cases, charge exchange and associated reactions are the main reaction channels, and clustering is not observed.
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502
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Ma S, Thompson J, Hu H, Neville DM. Expression and characterization of a divalent chimeric anti-human CD3 single chain antibody. Scand J Immunol 1996; 43:134-9. [PMID: 8633192 DOI: 10.1046/j.1365-3083.1996.d01-22.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Murine anti-CD3 monoclonal antibodies (MoAbs) are used in clinical practice for immunosuppression. However, there are two major drawbacks to this treatment: the associated cytokine release syndrome and human anti-mouse antibody response. To overcome these side-effects, the authors generated a chimeric anti-human CD3 single chain antibody, scUCHT1. It is an IgM variant of UCHT1, a mouse IgG1 MoAb directed against human CD3. scUCHT1 consists of the light and heavy variable chain binding domains of UCHT1 and a human IgM Fc region (CH2 to CH4). scUCHT1 was produced by COS-7 and SP2/0 transfectants, and mainly assembled in a dimeric form. It retained the binding specificity and affinity of the parental MoAb UCHT1. In contrast to UCHT1, scUCHT1 did not induce T-cell proliferation and cytokine release (TNF-alpha and IFN-gamma) in in vitro assays. These results suggest that the engineered chimeric anti-CD3 single chain antibody (scUCHT1) may be useful in clinical immunosuppressive treatment.
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503
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Ma S, Kálmán F, Kálmán A, Thunecke F, Horváth C. Capillary zone electrophoresis at subzero temperatures. I. Separation of the cis and trans conformers of small peptides. J Chromatogr A 1995; 716:167-82. [PMID: 8574385 DOI: 10.1016/0021-9673(95)00555-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The cis-trans conformers of two dipeptides, Phe-Pro and Leu-Pro, and two opioid heptapeptides containing one or two proline residues were separated by capillary zone electrophoresis (CZE) in borate buffer at low temperatures down to -17 degrees C. At temperatures near ambient, the relaxation time of the cis-trans isomerization is on the time-scale of minutes for the dipeptides and thus commensurate with the migration times in CZE under usual operating conditions. The conformers of both dipeptides could be separated with baseline resolution below 10 degrees C in neat aqueous 100 mM sodium borate (pH 8.4). The conformer peaks on the electropherograms were identified by using authentic samples of the cis and trans forms of Phe-Pro and Leu-Pro that were obtained by reversed-phase HPLC at 0 degree C, validated by NMR spectroscopy and stored in liquid nitrogen. The interplay of the electrophoretic migration and on-column isomerization reaction in CZE of Phe-Pro under various conditions was analyzed in the light of the Damköhler number (Da). The results showed that besides employing low temperature increasing the voltage and/or decreasing the capillary length also reduce the magnitude of Da to bring about the separation of interconverting species. In this work the use of low temperature in this work was preferred due to the experimental simplicity. The separation of cis-trans conformers of two opioid heptapeptides was carried out by CZE at subzero temperatures with aqueous sodium borate containing 23% (v/v) glycerol at pH* 11.3 as measured with a glass electrode. The two conformers of Tyr-Pro-Phe-Asp-Val-Val-Gly-NH2 were baseline separated at -12 degrees C and the four conformers of Tyr-Pro-Phe-Gly-Tyr-Pro-Ser-NH2 due to the presence of two peptidyl-proline bonds in the molecule, were also resolved at -12 degrees C. From the electrophoretic mobilities, the hydrodynamic radii of the cis-trans conformers of the dipeptides Phe-Pro and Leu-Pro were estimated. In both cases, the trans isomers had 1.3 times greater Stokes radii than the cis conformers. This agrees with the observed migration order and molecular modeling results. The hydrodynamic radii of the Phe-Pro conformers were smaller than those of the Leu-Pro isomers despite the lower molecular mass of the latter. The results demonstrate that CZE is suitable for measuring certain molecular properties and suggest that the methods introduced here are applicable to the study of other systems of interconverting conformers.
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504
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Ma S, Lin L, Raghavan R, Cohenour P, Lin PY, Bennett J, Lewis RJ, Enwall EL, Kostrzewa R, Lehr RE. In vivo and in vitro studies on the neurotoxic potential of 6-hydroxydopamine analogs. J Med Chem 1995; 38:4087-97. [PMID: 7562944 DOI: 10.1021/jm00020a024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In an attempt to determine which physical and biological properties could best be correlated with neurotoxic potential, seven analogs of 1-(2,4,5-trihydroxyphenyl)-2-aminoethane (1), better known as 6-hydroxydopamine, were synthesized and compared to 1 in a variety of ways both in vivo and in vitro. The analogs, in combination with the standard 1, include all eight of the 2,4,5-trisubstituted-phenyl derivatives of phenethylamine and alpha-methylphenethylamine in which the substitution is of the trihydroxy or aminodihydroxy form. Low (60 nmol) and high (300 nmol) intracerebroventricular doses of all analogs produced long-term (7 day) reduction of mouse whole brain norepinephrine (NE) and lesser depletions of dopamine (DA), and effects on serotonin were varied. The analog 1-(5-amino-2,4-dihydroxyphenyl)-2-aminopropane (8) was both more complete and more selective than the standard 1 in depleting NE. Using a histofluorometric glyoxylic acid method and Fink-Heimer silver degeneration stain, it was determined that overt neural degeneration was produced by 8. In vitro, the ease of oxidation of the eight analogs was found to be represented by a formal potential range of -130 to -212 mV vs SCE. However, there was no obvious relationship between ease of oxidation and the extent of monoamine depletion from mouse brain. Using kinetic analysis of synaptosomal accumulation of [3H]NE and [3H]DA, it was found that the standard 1 is more potent in its interaction with the DA uptake site (Ki = 12 +/- 0 microM) than the NE uptake site (Ki = 51 +/- 1 microM). A correlation analysis was used to determine that differences in NE and DA depletion by each analog could not be explained by differences in potency for in vitro uptake blockade. However, there was a correlation between the Ki for [3H]NE uptake blockade and the EC50 for synaptosomal release of preloaded [3H]NE for the eight analogs (R2 = 0.96; for log:log plot, R2 = 0.54), indicating that the results for these two in vitro tests both reflect interaction with the same NE neuronal membrane transport site. A similar correlation between Ki and EC50 was shown for all eight analogs using [3H]DA (R2 = 0.92; for log:log plot, R2 = 0.52), indicating interaction with the same DA neuronal membrane transport site. These findings demonstrate that there is no single property that can account for selectivity of action and/or potency of catecholamine neurotoxins related to 6-hydroxydopamine.
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505
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Lai ML, Hsu YI, Ma S, Yu CY. Magnetic resonance spectroscopic findings in patients with subcortical ischemic stroke. ZHONGHUA YI XUE ZA ZHI = CHINESE MEDICAL JOURNAL; FREE CHINA ED 1995; 56:31-35. [PMID: 7553407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
BACKGROUND Biochemical changes inside the brain during acute ictus have been extensively studied by means of magnetic resonance spectroscopy (MRS). Previous reports revealed that cerebral cortical infarction causes reduction of N-acetylaspartate (NAA) and elevation of lactate. This study was designed to evaluate the biochemical changes in subcortical infarction. METHODS Nine normal controls and four patients, including two thalamic infarct, one basal ganglia infarct, and one putamen infarct cases were examined using MRS in addition to magnetic resonance imaging (MRI). Evaluation experiments were performed on a Siemens Wagnetom 63SP machine. A spin echo sequence with TE 270 msec was applied for the measurement. The voxel was located at basal ganglia in the controls and at the lesion site, as well as at the contralateral corresponding region in the patients. RESULTS Three resonance signals were present in the spectrum-NAA, choline-containing compounds (Cho) and creatine-phosphocreatine (Cr). The NAA/Cho and NAA/Cr ratios were reduced significantly on the lesion side compared with the controls. NAA/Cho also decreased on the lesion side compared with the healthy side. CONCLUSIONS There is a remarkable reduction of NAA concentration even in subcortical infarction. Further study is needed for the detection of changes in lactate in patients with subcortical lesion.
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506
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Yu Y, Ma Y, Xia T, Ma S, Zhu M, Wan F, Wang Y. [Action of Rhodobrum roserm Limpr on changes of red cell aggregation and yield-shear stress in dogs with acute experimental coronary occlusion]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1995; 20:429-31, 449. [PMID: 7576145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Following acute occlusion of the left anterior descending coronary artery in dogs, significant increases were observed in the red cell aggregation index, yield-shear stress and red cell electrophoretic time in blood drained from ischemic area. When transfusion was performed with Rhodobrum roseum solution from the right femoral vein, significant rises of the above-said items were observed.
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507
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Abstract
The electrophoretic migration behavior of 12 S. nuclease variants from Staphylococcus aureus with small but well defined structural differences from site directed mutation was investigated in free solution capillary electrophoresis at pH 2.8 to 9.5. The nucleases are basic proteins; the pI and the M(r) of the wild type are 10.3 and 16.811 kd, respectively. With specially selected oligoamino buffers and with an inert, hydrophilic wall coating in 75 microns I.D. quartz capillary tubes, most of the proteins could be separated by CZE without interference by wall adsorption even at pH 9.5 where the selectivity was the highest. At pH 2.8, 4.1 and 7.0, S. nucleases are known to be in the random coil, "swollen" and the tight native state. Assuming that in a given state, i.e., at a certain pH, the molecular radii of the nucleases are the same, their hydrodynamic radii were calculated from their pertinent electrophoretic mobilities. The respective radii of 50.1, 26.8, and 25.0 Angstrum thus obtained agreed very well with the corresponding radii of gyration obtained from X-ray scattering. In fact, from the electrophoretic mobilities at pH 9.5, the existence of a hitherto unknown swollen basic state of the nuclease having a hydrodynamic radius of 30.5 Angstrum was postulated. In addition, a method was described to evaluate the valence of the protein at different pH from their pertinent electrophoretic mobilities. A general advantage of this method is that only the differences between the valences of the mutants and the wild type are needed; and for none of the proteins is required the knowledge of the actual valence. The results of the methods allowed the construction of a pH profile of the protein's valence. For the wild type, this profile was compared to the H+ titration curve and the agreement was excellent. Both methods employed some novel structure-electrophoretic mobility relationships and the predicted protein properties compared remarkably well to the values obtained by exoelectrophoretic methods such as pH titration and X-ray scattering. Surprisingly, certain S. nucleases having the same valence could also be readily separated by CZE in some cases under the same conditions used for the others. Close examination of appropriate X-ray crystallography and/or NMR data indicated subtle differences in the molecular structure of these proteins that could be responsible for slight alteration in their hydrodynamic radii.(ABSTRACT TRUNCATED AT 400 WORDS)
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508
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Ma S, Kalousek DK, Yuen BH, Moon YS. The chromosome pattern of embryos derived from tripronuclear zygotes studied by cytogenetic analysis and fluorescence in situ hybridization. Fertil Steril 1995; 63:1246-50. [PMID: 7750595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE To detect the chromosomal complement of embryos, which developed from tripronuclear zygote, using nonradioactive centromeric probes. DESIGN The chromosome pattern of embryos developing from tripronuclear zygote, studied by fluorescence in situ hybridization, was compared with that of embryos studied by standard cytogenetic methods. SETTING These embryos were obtained from superovulated patients undergoing IVF treatment. RESULTS We have attempted to examine the chromosomal complement of 72 embryos derived from tripronuclear zygotes using both traditional cytogenetic analysis and fluorescence in situ hybridization. Of these 72 embryos, 22 were analyzed with fluorescence in situ hybridization and 50 were analyzed with traditional cytogenetic analysis. For fluorescence in situ hybridization analysis, probes specific for the centromeric regions of chromosomes 1, 16, and X were used, with results being obtained from 18 embryos. One embryo was haploid (5.6%), five were triploid (27.8%), and one was hexaploid (5.6%). Eleven (61%) embryos were mosaic. Traditional cytogenetic analysis could be performed on 25 of 50 embryos. Five (20%) were haploid, one (4%) was diploid, seven (28%) were triploid, one (4%) were tetraploid, and two were hexaploid. Nine (36%) were mosaic. CONCLUSION These findings indicate that not all tripronuclear human zygotes develop into triploid embryos. This study also demonstrates the usefulness of fluorescence in situ hybridization for preimplantation diagnosis and screening for chromosome abnormalities.
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509
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Ma S, Feldman AG. Two functionally different synergies during arm reaching movements involving the trunk. J Neurophysiol 1995; 73:2120-2. [PMID: 7623104 DOI: 10.1152/jn.1995.73.5.2120] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
1. To address the problem of the coordination of a redundant number of degrees of freedom in motor control, we analyzed the influence of voluntary trunk movements on the arm endpoint trajectory during reaching. 2. Subjects made fast noncorrected planar movements of the right arm from a near to a far target located in the ipsilateral work space at a 45 degrees angle to the sagittal midline of the trunk. These reaching movements were combined with a forward or a backward sagittal motion of the trunk. 3. The direction, positional error, curvature, and velocity profile of the endpoint trajectory remained invariant regardless of trunk movements. Trunk motion preceded endpoint motion by approximately 175 ms, continued during endpoint movement to the target, and outlasted it by 200 ms. This sequence of trunk and arm movements was observed regardless of the direction of the endpoint trajectory (to or from the far target) or trunk movements (forward or backward). 4. Our data imply that reaching movements result from two control synergies: one coordinates trunk and arm movements leaving the position of the endpoint unchanged, and the other produces interjoint coordination shifting the arm endpoint to the target. The use of functionally different synergies may underlie a solution of the redundancy problem.
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510
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Ma S, Shieh LI, Huang CC. High-resolution proton nuclear magnetic resonance studies of urine from asphyxiated newborn infants. Appl Biochem Biotechnol 1995; 53:37-51. [PMID: 7625824 DOI: 10.1007/bf02783480] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
High-resolution proton nuclear magnetic resonance spectroscopy was used to study human urine obtained from 10 normal babies and twenty babies with various degrees of neonatal asphyxia, respiratory distress syndrome (RDS), and meconium aspiration syndrome (MAS). All sick babies showed different degrees of oxygen deficiency, indicated by an obvious increase of the lactate signal level in the urine spectra. Changes in the concentration of other urinary metabolites produced from the citric acid cycle were also observed. In extremely serious cases, the signals of some of the major components, including citrate, alpha-ketoglutarate, and succinate, simply disappeared. The spectra of urine, serum, and CSF of an infant suffering from SIDS showed common characteristics of the metabolites.
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511
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Kálmán F, Ma S, Hodel A, Fox RO, Horváth C. Charge and size effects in the capillary zone electrophoresis of nuclease A and its variants. Electrophoresis 1995; 16:595-603. [PMID: 7588531 DOI: 10.1002/elps.1150160196] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The migration behavior of nuclease A from Staphylococcus aureus and 11 of its variants in capillary zone electrophoresis (CZE) was investigated in the light of their three-dimensional structure known from X-ray crystallography and nuclear magnetic resonance (NMR) measurements. Nuclease A (molecular mass 16.8 kDa, pKa 10.3) and the variants differ only in a single amino acid residue and have a very similar crystal structure. With the use of coated quartz capillaries and suitable buffers, the protein migration was investigated at pH from 2.8 to 9.5 without interference by wall adsorption. Although the selectivity of the electrophoretic system for the proteins was mainly determined by their charge differences, certain variants having the same net charge could also be readily separated under nondenaturing conditions. For instance, the mobility of variant K116A was sufficiently higher than that of K116G so that they could be separated by CZE. The structures of both variants are the same except for the solvent-exposed loop containing residue 116. For this reason, the difference in electrophoretic mobilities can be attributed to the fact that in K116G the backbone of the 112 to 117 amino acids protrudes slightly from the protein, with a concomitant increase in the hydrodynamic radius with respect to that of K116A. Consequently, K116G shows a smaller mobility than K116A due to its larger hydrodynamic radius despite its smaller molecular mass. The interpretation of the experimentally measured mobilities of such closely related proteins therefore requires not only consideration of their electrostatic charge but also the fine details of their molecular structures.
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512
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Ma S, Lin D, Sun J. [Adenocarcinoma of the cervix--analysis of 363 cases]. ZHONGHUA ZHONG LIU ZA ZHI [CHINESE JOURNAL OF ONCOLOGY] 1995; 17:149-51. [PMID: 7656810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Form 1959 through to May, 1993, 363 patients with adenocarcinoma of uterine cervix were initially treated which accounted for 2.5% of all initially treated cases of cervical carcinoma. Patients' mean age was 50.5 years. Forty-six percent of the patients were post-menopausal. The main symptom was irregular vaginal and/or discharge. Over 88% of the cases were in stage II and III of the disease. They were treated with radiotherapy alone. The overall 5-year survival rate was 51.8%. The recurrence rate was 17.4% with a mean time to recurrence of 33.3 months. Thirteen patients recurred beyond 5 years. Recurrence was accompanied with lung metastasis in 17 patients and supraclavicular eymph node metastases in 11. Among patients whose tumor recurred the 1- and 2-year survival rate were 35.2% and 19.2% respectively. The most significant prognostic factors were the stage of disease, the size of the tumor and the histologic subtypes
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513
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Gurram R, Rakheja S, Gouw GJ, Ma S. Influence of power tool-related parameters on the response of finger flexor muscles. Int Arch Occup Environ Health 1995; 66:393-8. [PMID: 7782123 DOI: 10.1007/bf00383146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Surface electromyography (EMG) and statistical analysis techniques were applied to investigate the response of finger flexor muscles to hand-transmitted vibration in all the three orthogonal directions. The trends in measured data were examined to derive the influence of variations in the tool-related parameters. Single-factor and multi-factor statistical analyses were performed to establish the significance of influence of different individual and coupled power tool-related parameters. The analysis of variance (ANOVA) results indicated that the vibration direction, acceleration and grip force influence the EMG of finger flexor muscles in a significant manner (P < 0.001), while the effect of vibration frequency was observed to be insignificant (P > 0.9). The electrical activity measured under different vibratory test conditions was observed to be 1.5-6.0 times higher than that measured under the static loads. The increase in electrical activity of the finger flexor muscles with an increase in the grip force was observed to be most significant under static as well as dynamic loading conditions.
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514
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Ma S, Reich DH, Broholm C, Sternlieb BJ, Erwin RW. Spin correlations at finite temperature in an S=1 one-dimensional antiferromagnet. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:3289-3292. [PMID: 9979131 DOI: 10.1103/physrevb.51.3289] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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515
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Ma S, Abboud FM, Felder RB. Effects of L-arginine-derived nitric oxide synthesis on neuronal activity in nucleus tractus solitarius. THE AMERICAN JOURNAL OF PHYSIOLOGY 1995; 268:R487-91. [PMID: 7864245 DOI: 10.1152/ajpregu.1995.268.2.r487] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The purpose of these studies was to determine the effects of L-arginine-derived nitric oxide (NO) synthesis on neuronal activity in solitary tract nucleus (NTS) neurons. Single unit activity was recorded extracellularly from medial NTS neurons in Fischer-344 rats in vivo and in vitro. In anesthetized rats with arterial pressure maintained constant, NG-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg iv), an inhibitor of NO synthesis, decreased the discharge rate in 12 of 14 neurons and increased the discharge rate in two. After injection of L-NAME, the slowing of neuronal activity began within 2-5 min, and maximal responses were observed 12-15 min after injection. The decreases in activity were reversed within 12-15 min with L-arginine (30 mg/kg iv) or immediately with nitroglycerin (NTG, 10-30 micrograms/kg iv). In superfused rat brain slices, the discharge rate was reduced by 1 mM L-NAME in seven neurons, increased in two, and unchanged in one. The decreases in discharge rate were reversed by 2 mM L-arginine (4 of 6 neurons) and by 10-30 microM NTG (6 of 7 neurons). The results show that L-arginine-derived NO can affect the spontaneous discharge rate of NTS neurons. We conclude that NO may influence the excitability of NTS neurons involved in central autonomic control.
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516
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Campbell P, Ma S, Yeom B, McKellop H, Schmalzried TP, Amstutz HC. Isolation of predominantly submicron-sized UHMWPE wear particles from periprosthetic tissues. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1995; 29:127-31. [PMID: 7713952 DOI: 10.1002/jbm.820290118] [Citation(s) in RCA: 291] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A method of tissue digestion using sodium hydroxide was applied to the isolation and recovery of ultra-high-molecular-weight polyethylene (UHMWPE) particles from tissues around failed total hip replacements. Density gradient ultracentrifugation of the digested tissues was performed to separate the UHMWPE from cell debris and other particulates. Fourier transform infrared spectroscopy and differential scanning calorimetry (DSC) verified that the recovered particles were UHMWPE. When viewed by scanning electron microscopy, individual particles were clearly observed and were either rounded or elongated. The majority were submicron in size. The application of this method to the study of particles from periprosthetic tissues may elucidate aspects of biomaterial particle size and shape that are important to the biologic response to, and clinical outcome of, total joint replacement.
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517
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L'Abbé D, Banville D, Tong Y, Stocco R, Masson S, Ma S, Fantus G, Shen SH. Identification of a novel protein tyrosine phosphatase with sequence homology to the cytoskeletal proteins of the band 4.1 family. FEBS Lett 1994; 356:351-6. [PMID: 7805871 DOI: 10.1016/0014-5793(94)01305-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Use of the polymerase chain reaction (PCR) in conjunction with Southern hybridization, using probes corresponding to known phosphatase sequences, resulted in the identification of rat cDNA clones encoding a novel protein tyrosine phosphatase which was termed rPTP2E. The cDNAs comprise 5,543 bp and predict a polypeptide of 1175 amino acids possessing a single catalytic domain at its C-terminus. The N-terminal region of the deduced polypeptide displays high sequence homology to the cytoskeleton-associated proteins of the band 4.1 family. A variant form, termed rPTP2E1, was also identified which contains the catalytic domain only. rPTP2E and rPTP2E1 were expressed in various rat tissues, particularly abundantly in adrenal glands. The catalytic domain of PTP2E was expressed in Escherichia coli and was shown to possess specific protein tyrosine phosphatase activity. The identification of rPTP2E suggests the existence of a subfamily of band 4.1 domain-containing PTPs which may play an important role in signalling pathway and control of cytoskeletal integrity.
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518
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Gout PW, Horsman DE, Fox K, De Jong G, Ma S, Bruchovsky N. The rat Nb2 lymphoma: a novel model for tumor progression. Anticancer Res 1994; 14:2485-92. [PMID: 7872671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Tumor progression of cancers is manifested by phenotypic property changes including development of hormone/growth factor independence and metastatic ability. The progression results from acquired genomic alterations leading to clonal heterogeneity and outgrowth of more aggressive and therapy-resistant sublines. Previously, a cultured rat "Nb2 lymphoma" cell line was established, whose viability depends critically on the hormone, prolactin, acting as the principal growth factor. By prolactin starvation, prolactin-independent sublines were generated which possessed the parent karyotype plus extra acquired chromosomal changes (clonal evolution). In this study, the parent line (Nb2-U17) and a cloned subline (SFJCD1) were compared for metastatic ability using single s.c. tumor transplants in Noble rats. Rats (22) bearing Nb2-U17 tumors showed no evidence of metastases at autopsy, even when tumors at implantation site reached a size of 9 cm (length + width). In contrast, rats (19) bearing SFJCD1 tumors showed multiple metastases (liver, kidney) when transplants exceeded 5 cm. This difference in metastatic ability may be related to the acquisition of an inversion in chromosome 1, i.e. inv(1)(q31q41). The 1q41 locus is adjacent to the reported H-ras-1 proto-oncogene locus (1q41-q42). In another subline, tetraploidization (flow cytometric analysis, karyotyping) occurred spontaneously following prolonged culturing (20 mo). Together, the parent Nb2 lymphoma line and its clonal derivatives provide a novel system for studying cellular and molecular mechanisms underlying tumor progression to the metastatic phenotype.
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519
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Abstract
The improvement of endoscopic technology has revolutionized surgery, and endoscopy has become a trend in recent years. In plastic surgery, endoscopic release of the carpal tunnel and endoscopic face-lifting have been used clinically. However, no report has been noted that deals with the bone of the face. Using pigs as the animal model, endoscopic resection of the mandibular angles was undertaken. The result was satisfactory; it appears that it can also be effective in humans.
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520
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Liu K, Liu W, Li X, Xia Y, Wan G, Yang S, Ma S, Huang X, Qi X, Liang J. Pericardiocentesis and drainage by a silicon rubber line without echocardiographic guidance. Experience in 55 consecutive patients. JAPANESE HEART JOURNAL 1994; 35:751-6. [PMID: 7897821 DOI: 10.1536/ihj.35.751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Pericardiocentesis and drainage with a silicon rubber line were performed safely in 55 patients via the subxiphoid (80 times) or apical (1 time) approach at the bedside without echocardiographic guidance. The subxiphoid approach, which is close to the posterior of the sternum or the costal cartilage with a small acute-angle (15-30 degrees) to the parietal pericardium in front of the right ventricle, can avoid injuring the heart, liver and lungs. A line with sideholes near the distal end, which provides convenient drainage and has better histocompatibility, can be kept in place for a long period of time (1-82 days). It was also convenient to inject air, drugs or fluid through the line. There were no procedure-related serious complications or deaths. Emergency drainage with the Seldinger technique, especially for small to moderate effusions, is safe and simple.
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521
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Ma S, Kalousek DK, Yuen BH, Gomel V, Katagiri S, Moon YS. Chromosome investigation in in vitro fertilization failure. J Assist Reprod Genet 1994; 11:445-51. [PMID: 7633164 DOI: 10.1007/bf02215706] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
PURPOSE A chromosomal complement of 227 human oocytes was studied to provide information on the frequency and type of chromosomal abnormalities in oocytes failing in vitro fertilization. RESULTS Normal haploid chromosome complement was found in 54.6%; chromosomal abnormalities consisting of diploid sets were identified in 16.7% and aneuploidy was observed in 26%. Premature condensation of sperm chromosomes of the GI-phase was observed in 22.9% oocytes. Male infertility was correlated with an increase in the rate of aneuploidy when compared with tubal infertility. The rate of chromosome abnormalities for the oocytes recovered from women who had no fertilized oocytes was significantly higher compared to those with at least one oocyte fertilized. CONCLUSION A high frequency of chromosome abnormalities in unfertilized oocytes suggests that natural selection against chromosome abnormalities may occur even prior to fertilization.
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522
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Wu WH, Ma S, Lin JT, Tang YW, Fang RH, Yeh FL. Surgical treatment of axillary osmidrosis: an analysis of 343 cases. Plast Reconstr Surg 1994; 94:288-94. [PMID: 8041819 DOI: 10.1097/00006534-199408000-00011] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
From July of 1986 to July of 1992, 343 patients have received surgery for axillary osmidrosis by partially removing skin and cellular tissue en bloc and removing the subcutaneous cellular tissue of the adjacent area. A total of 102 patients were followed for 4 months to 6 years, with an average of 32 months. The total satisfaction rate was 91 percent (93 of 102). The wound complication rate was 6.715 percent (46 of 685). There were no scar contractures or limitations of arm abduction. In this paper we emphasize three merits of our procedure. One is that partially removing the skin promises definite excision of more than half the eccrine glands which were located in the dermis of the operative field. The second merit is good exploration for undermining and defatting of the under-surface of the adjacent area. The third merit is a low wound complication rate because the width of the skin excision is less than 3 cm. Therefore, partial removal of skin and cellular tissue en bloc and the subcutaneous cellular tissue of the adjacent area is the choice for surgical treatment for axillary osmidrosis.
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523
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Ma S, McGregor MJ, Cohen FE, Pallai PV. Conformation of CD4-derived cyclic hexapeptides by NMR and molecular dynamics. Biopolymers 1994; 34:987-1000. [PMID: 8075393 DOI: 10.1002/bip.360340802] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Two cyclic hexapeptides, cyclo[Ala1-D-Ala2-Ser3-Phe4-Gly5-Ser6] and cyclo[Ala1-Gly2-Ser3-Phe4-Gly5-Ser6], derived from the loop portion of the C'C" ridge of CD4, were characterized by high-resolution nmr spectroscopy and simulated annealing studies. In DMSO-d6 both of these peptides display a single conformer on the nmr time scale with two intramolecular H-bond (1<--4) stabilized beta-turns at positions 2-3 and 5-6. The nmr derived distance constraints were used in simulated annealing calculations to generate the solution structures. These structures adopt energetically comparable conformational substates that are not resolvable on the nmr time scale. In aqueous solution, the H-bond stabilized beta-turn conformation for cyclo[Ala-D-Ala-Ser-Phe-Gly-Ser] is no longer the predominant structural form. Structures generated using molecular dynamics simulations with no experimental constraints were compared with those from nmr analysis. The correlation between these two sets of structures allows the use of molecular simulations as a predictive tool for the conformational analysis of small peptides.
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524
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Bürger H, Kuna R, Ma S, Breidung J, Thiel W. The vibrational spectra of krypton and xenon difluoride: High‐resolution infrared studies and ab initio calculations. J Chem Phys 1994. [DOI: 10.1063/1.468170] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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525
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Ma S, Zhou S. [Effects of phenytoin and cabamazepine on sex hormones in male patients with epilepsy: a controlled study]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 1994; 25:212-4. [PMID: 7806203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We measured the levels of estradiol (E2), total testosterone (TT) and free testosterone (FT) in 24 male patients with epilepsy receiving phenytoin (DPH), 21 male patients with epilepsy receiving cabamazepine (CBZ), 23 male epileptics receiving no treatment, and in 10 healthy age-matched male controls. The FT and TT levels of the DPH group were significantly lower and higher than those of the normal control group, respectively. The E2, FT and TT of the CBZ group were all lower than those of the normal controls. The results showed the difference between DPH and CBZ in the mechanism of affecting the levels of sex hormones; therefore, the treatments should not be the same.
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526
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Shi Y, Shi H, Ma S. [Molecular cytogenetic study of Turner's syndrome with the 45, X/46,X,r(?) karyotype]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 1994; 16:218-21. [PMID: 7805169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Two small marker chromosomes were identified as X-derived ring chromosomes by using the high-resolution banding technique and in situ hybridization with a radioactively labelled human X-chromosome-specific satellite DNA probe. This procedure clearly determined the origin of the marker chromosome, which had been impossible using conventional cytogenetic techniques. The clinical significance of this work is briefly discussed.
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527
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Campbell P, Ma S, Schmalzried T, Amstutz HC. Tissue digestion for wear debris particle isolation. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1994; 28:523-6. [PMID: 8006056 DOI: 10.1002/jbm.820280415] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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528
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Roy S, Martel J, Ma S, Tenenhouse HS. Increased renal 25-hydroxyvitamin D3-24-hydroxylase messenger ribonucleic acid and immunoreactive protein in phosphate-deprived Hyp mice: a mechanism for accelerated 1,25-dihydroxyvitamin D3 catabolism in X-linked hypophosphatemic rickets. Endocrinology 1994; 134:1761-7. [PMID: 8137741 DOI: 10.1210/endo.134.4.8137741] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
X-Linked Hyp mice exhibit rachitic bone disease, hypophosphatemia, impaired renal phosphate reabsorption, and abnormal regulation of renal 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] metabolism. We demonstrated that phosphate deprivation of Hyp mice, but not normal littermates, elicits a dramatic fall in serum 1,25-(OH)2D levels and an increase in renal 1,25-(OH)2D3 catabolism that can be ascribed to an increase in the activity of renal mitochondrial 25-hydroxyvitamin D3-24-hydroxylase (24-hydroxylase), the first enzyme in the C-24 oxidation pathway. The present study was undertaken to elucidate the mechanism for the increase in renal 24-hydroxylase activity in phosphate-deprived Hyp mice. Phosphate deprivation of Hyp mice resulted in a 3-fold increase in the maximum velocity for 24-hydroxylase (n = 5; P < 0.001) accompanied by an increase in 24-hydroxylase immunoreactive protein relative to the level of ornithine aminotransferase. Phosphate deprivation of Hyp mice also elicited a 3-fold increase in renal 24-hydroxylase mRNA abundance relative to that of beta-actin mRNA (n = 7; P < 0.001). The increase in 24-hydroxylase mRNA was specific to the kidney and was evident as early as 1 day of the low phosphate diet. Phosphate deprivation had no effect on renal 24-hydroxylase immunoreactive protein or mRNA in normal littermates. In contrast to the abnormal 24-hydroxylase response to dietary phosphate, Hyp mice exhibited an appropriate increase in renal 24-hydroxylase mRNA and catalytic activity in response to increasing doses of 1,25-(OH)2D3. The present results demonstrate that elevated renal 24-hydroxylase activity in phosphate-deprived Hyp mice can be ascribed to an increase in the abundance of 24-hydroxylase mRNA and protein and suggest that inappropriate regulation of 1,25-(OH)2D3 catabolism in Hyp mice occurs at the pretranslational level.
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529
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Kubo M, Matsuda H, Tokuoka K, Kobayashi Y, Ma S, Tanaka T. Studies of anti-cataract drugs from natural sources. I. Effects of a methanolic extract and the alkaloidal components from Corydalis tuber on in vitro aldose reductase activity. Biol Pharm Bull 1994; 17:458-9. [PMID: 8019518 DOI: 10.1248/bpb.17.458] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The inhibitory of Corydalis tuber (Corydalis turtschaninovii Besser forma yanhusuo Y. H. Chou et C. C. Hsu) was tested on crude rat lens aldose reductase, an enzyme involved in the complications of diabetes. The methanolic extract (CM-ext) inhibited aldose reductase, while the aqueous extract (CA-ext) was ineffective. Only dehydrocorydaline, of the seven alkaloidal components isolated from CM-ext, inhibited aldose reductase. It is suggested that the inhibitory effect of CM-ext on aldose reductase may be partially attributed to dehydrocorydaline.
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530
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Tenenhouse HS, Werner A, Biber J, Ma S, Martel J, Roy S, Murer H. Renal Na(+)-phosphate cotransport in murine X-linked hypophosphatemic rickets. Molecular characterization. J Clin Invest 1994; 93:671-6. [PMID: 8113402 PMCID: PMC293897 DOI: 10.1172/jci117019] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The X-linked Hyp mouse is characterized by a specific defect in proximal tubular phosphate (Pi) reabsorption that is associated with a decrease in Vmax of the high affinity Na(+)-Pi cotransport system in the renal brush border membrane. To understand the mechanism for Vmax reduction, we examined the effect of the Hyp mutation on renal expression of Na(+)-Pi cotransporter mRNA and protein. Northern hybridization of renal RNA with a rat, renal-specific Na(+)-Pi cotransporter cDNA probe (NaPi-2) (Magagnin et al. 1993. Proc. Natl. Acad. Sci. USA. 90:5979-5983.) demonstrated a reduction in a 2.6-kb transcript in kidneys of Hyp mice relative to normal littermates (NaPi-2/beta-actin mRNA = 57 +/- 6% of normal in Hyp mice, n = 6, P < 0.01). Na(+)-Pi cotransport, but not Na(+)-sulfate cotransport, was approximately 50% lower in Xenopus oocytes injected with renal mRNA extracted from Hyp mice when compared with that from normal mice. Hybrid depletion experiments documented that the mRNA-dependent expression of Na(+)-Pi cotransport in oocytes was related to NaPi-2. Western analysis demonstrated that NaPi-2 protein is also significantly reduced in brush border membranes of Hyp mice when compared to normals. The present data demonstrate that the specific reduction in renal Na(+)-Pi cotransport in brush border membranes of Hyp mice can be ascribed to a proportionate decrease in the abundance of Na(+)-Pi cotransporter mRNA and protein.
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531
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Kubo M, Matsuda H, Tokuoka K, Ma S, Shiomoto H. Anti-inflammatory activities of methanolic extract and alkaloidal components from Corydalis tuber. Biol Pharm Bull 1994; 17:262-5. [PMID: 7515744 DOI: 10.1248/bpb.17.262] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A methanolic extract (CM-ext) from Corydalis tuber (Corydalis turtschaninovii Besser forma yanhusuo Y. H. Chou et C. C. Hsu) has been screened for activity in experimental models of inflammation. CM-ext (200 or 500 mg/kg, p.o.) inhibited an increase in vascular permeability in mice induced by acetic acid, and reduced acute paw edema in rats induced by compound 48/80 or carrageenin. CM-ext suppressed the development of adjuvant-induced edema in arthritic rats. CM-ext and its alkaloidal components, dehydrocorydaline, d-glaucine and l-tetrahydrocoptisine inhibited compound 48/80-induced histamine release from peritoneal mast cells of rats. Since these substances from C. tuber were found to be effective in both the acute and chronic phases of inflammation, the crude drug C. tuber can be considered to exert anti-inflammatory activity.
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532
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Abstract
One of the primary goals of phalloplasty on female to male transsexuals is to void while standing. However, achieving competence of the neourethra, sensation, and rigidity of the neophallus still present a challenge. Over a 5 year period (1988-1993), 56 phalloplasties using sensate free forearm flaps were performed for 56 primary female transsexuals. The urethrocutaneous fistula rate was 38/56 and one flap totally necrosed. However, when the flap was prefabricated with a tubed graft of vaginal mucosa for the 28 cases (the later part of the series), there were less complications and a lower fistula rate within this portion of the neourethra. Although the whole procedure was time consuming, it was worthwhile and patient satisfaction was high.
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533
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Ma S. [Severe acute pancreatitis and ARDS]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1993; 31:517-20. [PMID: 8033713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A survey was done in 28 cases of severe acute pancreatitis with main interest on their respiratory appearance. It was noticed that at the early stage of the disease process the patients did develop some degree respiratory disorders but they were mild in severity. Only after successful resuscitation of septic shock and its accompanying diffuse body tissue injury, then followed severe clinical respiratory failure symptom which is now known as acute respiratory distress syndrome (ARDS). ARDS in this disease usually had two phases, one immediately after the early resuscitation, which was usually 2-3 days after the disease and followed by a period of recovery of respiratory syndrome and the second ARDS phase with fulminante clinical respiratory failure usually developed 10-14 days after the disease. The reburning phase of ARDS, was clinically very serious and went together with pulmonary infections in all cases. A discussion was made in this retrospective study about all the clinical findings, the risk factors and their reasonable treatments.
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534
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Ma S, Richardson JF, Spatola AF. Crystal structures of two cyclic pseudopentapeptides containing psi[CH2S] and psi[CH2SO] backbone surrogates. Biopolymers 1993; 33:1101-10. [PMID: 8343587 DOI: 10.1002/bip.360330712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The solid state conformations of cyclo [Gly-Pro psi[CH2S] Gly-D-Phe-Pro] and cyclo [Gly-Pro psi[CH2-(S)-SO]Gly-D-Phe-Pro] have been characterized by X-ray diffraction analysis. Crystals of the sulfide trihydrate are orthorhombic, P2(1)2(1)2(1), with a = 10.156(3) A, b = 11.704(3) A, c = 21.913(4) A, and Z = 4. Crystals of the sulfoxide are monoclinic, P2(1) with a = 10.662(1) A, b = 8.552(3) A, c = 12.947(2) A, beta = 94.28(2), and Z = 2. Unlike their all-amide parent, which adopts an all-trans backbone conformation and a type II beta-turn encompassing Gly-Pro-Gly-D-Phe, both of these peptides contain a cis Gly1-Pro2 bond and form a novel turn structure, i.e., a type II' beta-turn consisting of Gly-D-Phe-Pro-Gly. The turn structure in each of these peptides is stabilized by an intramolecular H bond between the carbonyl oxygen of Gly1 and the amide proton of D-Phe4. In the cyclic sulfoxide, the sulfinyl group is not involved in H bonding despite its strong potential as a hydrogen-bond acceptor. The crystal structure made it possible to establish the absolute configuration of the sulfinyl group in this peptide. The two crystal structures also helped identify a type II' beta-turn in the DMSO-d6 solution conformers of these peptides.
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535
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Ma S. [Experimental study on the effect of unilateral mastication on the morphology of mandibular joint]. ZHONGHUA KOU QIANG YI XUE ZA ZHI = ZHONGHUA KOUQIANG YIXUE ZAZHI = CHINESE JOURNAL OF STOMATOLOGY 1993; 28:151-3. [PMID: 8275806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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536
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Ma S, Fang RH. Iatrogenic bilateral femoral mycotic aneurysms: a case report following burns. Burns 1993; 19:83-4. [PMID: 8435125 DOI: 10.1016/0305-4179(93)90109-l] [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: 01/30/2023]
Abstract
Haemodynamic monitoring is important in severely burned patients and repeated catheterization of the arteries of these victims seems to be inevitable. We present a 46-year-old female with 54 per cent TBSA burns who suffered from bilateral femoral mycotic aneurysms due to repeated arterial punctures.
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537
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Ma S, Spatola AF. Conformations of psi [CH2NH] pseudopeptides. Cyclo[Gly-Pro psi [CH2NH]Gly-D-Phe-Pro]-TFA and cyclo[Gly-Pro psi [CH2NH]Gly-D-Phe-Pro]. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1993; 41:204-6. [PMID: 8458694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The cyclic pseudopentapeptide cyclo[Gly-Pro psi [CH2NH]Gly-D-Phe-Pro] and its TFA salt were synthesized by solution methods, and their conformations were studied by NMR spectroscopy in both DMSO-d6 and CDCl3. While intramolecular hydrogen bonding is observed with some conformers, the nature of the solvent and the presence of TFA affects the relative structural rigidities of the compounds. No evidence was found for the psi [CH2NH] or psi [CH2NH2+] units acting as H donors in this series.
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538
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Ma S. [Rapid screening of the Duchenne muscular dystrophy gene deletion by two multiplex PCR]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 1993; 15:74-8. [PMID: 8324844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Duchenne muscular dystrophy (DMD) is one of the most common lethal X-linked disorders. Partial intragenic deletions account for up to 60% of DMD deletions, and approximately one-third of all cases arise via new mutations. In this paper, two sets of primers were used for two multiplex PCR screenings of DMD gene deletions. The first set consists of 5 pairs of primers which amplify 5 exons with higher deletion frequencies, and the second set includes other 4 pairs of primers. Fifty-one DMD samples were screened by the first set, and then those not found to have deletions were screened by the second set. In total, 25 deletions were identified in the Fifty-one DMD samples: That is, about 49% of all cases studied were found to have deletions.
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539
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Ma S, Long JP. Hypotensive and bradycardiac responses to reflex sympathetic inhibition produced by nitroglycerin in rats with sinoaortic deafferentation. J Cardiovasc Pharmacol 1993; 21:136-43. [PMID: 7678669 DOI: 10.1097/00005344-199301000-00020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Nitroglycerin (NTG) may cause paradoxical bradycardia and occasional life-threatening hypotension. The mechanism is unclear. In this study, we compared the cardiovascular responses of sodium nitroprusside (SNP) with that of NTG in rats with sinoaortic deafferentation (SAD). Intravenous (i.v.) injection of SNP and NTG produced dose-dependent decreases in mean arterial pressure (MAP). SNP was more effective than NTG in increasing heart rate (HR). After SAD, tachycardiac responses to i.v. SNP were abolished, but i.v. NTG caused bradycardia. SAD enhanced the hypotensive responses of both NTG or SNP after i.v. administration. The bradycardic and hypotensive effects of NTG were attenuated by either bilateral vagotomy or intracisternal (i.c.) pretreatment with 20 nmol rauwolscine, but the responses were not altered by i.v. atropine methylbromide (M-atropine), 0.6 mumol. In contrast, cardiovascular responses to i.v. SNP after SAD were not altered by these pretreatments. Tachycardiac responses to intracerebroventricular (i.c.v.) injection of NTG were reduced by SAD, but SAD did not alter bradycardic responses to i.c. injection of NTG. These results suggest that NTG induces inhibitory reflexes that may contribute to its complex cardiovascular responses in rats. The drug may stimulate peripheral sensory receptors with vagal afferents to the medulla, which then triggers an alpha 2-adrenoceptor-mediated sympathoinhibition.
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540
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Ma S, Broholm C, Reich DH, Sternlieb BJ, Erwin RW. Dominance of long-lived excitations in the antiferromagnetic spin-1 chain NENP. PHYSICAL REVIEW LETTERS 1992; 69:3571-3574. [PMID: 10046855 DOI: 10.1103/physrevlett.69.3571] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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541
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Ripamonti U, Ma S, Cunningham NS, Yeates L, Reddi AH. Initiation of bone regeneration in adult baboons by osteogenin, a bone morphogenetic protein. MATRIX (STUTTGART, GERMANY) 1992; 12:369-80. [PMID: 1484504 DOI: 10.1016/s0934-8832(11)80033-8] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Osteogenin, and related bone morphogenetic proteins, induce endochondral bone differentiation through a cascade of events which include formation of cartilage, hypertrophy and calcification of the cartilage, vascular invasion, differentiation of osteoblasts, and formation of bone. These events have been studied in a postnatal model of bone development in rodents. Information concerning the morphogenetic potential of osteogenin in primates is a prerequisite for potential clinical application in man. The efficacy of allogeneic osteogenin in primates was investigated in both extraskeletal and skeletal sites in 19-Chacma baboons (Papio ursinus). Osteogenin was isolated from demineralized baboon bone matrix and purified by chromatography on heparin-Sepharose, hydroxyapatite, and Sephacryl S-200. Protein fractions with a molecular mass range of 26-42 kDa induced cartilage and bone differentiation in the subcutaneous space of rats. Final purification to homogeneity was obtained by electroendosmotic elution from a preparative sodium dodecyl sulphate (SDS) polyacrylamide gel, resulting in a single band on a SDS-polyacrylamide gel with an apparent molecular mass of 30-34 kDa, with biological activity in rats. The osteoinductive potential of osteogenin in primates was tested first in intramuscular sites in baboons and found to be active. The bone regeneration potential was investigated in nonhealing calvarial defects surgically prepared in adult male baboons. Baboon osteogenin induced complete regeneration of the cranial wound. These findings in adult primates establish a primary role for osteogenin in initiation and promotion of osteogenesis, and imply a potential therapeutic application based on cell biology of extracellular matrix-cell interactions.
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542
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Ripamonti U, Ma S, Reddi AH. The critical role of geometry of porous hydroxyapatite delivery system in induction of bone by osteogenin, a bone morphogenetic protein. MATRIX (STUTTGART, GERMANY) 1992; 12:202-12. [PMID: 1328828 DOI: 10.1016/s0934-8832(11)80063-6] [Citation(s) in RCA: 172] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The collagenous extracellular matrix of bone obtained after dissociative extraction with 4 M guanidine-HCl is an optimal substratum for bone induction by osteogenin, a bone morphogenetic protein. As a proteinaceous substratum, this matrix and other collagen-based materials may be immunogenic. Thus, the search and discovery of a non-immunogenic substratum is a necessary prerequisite for the therapeutic application of the principle of bone induction to skeletal repair. Bovine osteogenin, purified greater than 50,000-fold and with an apparent molecular mass of 28-42 kilodaltons, was delivered into nonresorbable porous hydroxyapatite in granular and disc configuration. A total of 328 preparations were bioassayed for osteogenic activity by subcutaneous implantation into 164 Long-Evans rats. Specimens were harvested at day 7, 11 and 21 after implantation and subjected to alkaline phosphatase activity determination and histologic analysis. Osteogenin combined with discs of porous hydroxyapatite induced in vivo differentiation of the osteogenic phenotype in mesenchymal cells invading the three-dimensional porous space of the inorganic substratum. The geometry of the substratum had a profound influence on bone induction, since the expression of the osteogenic phenotype was solely confined in porous hydroxyapatite with disc configuration. Osteogenin did not induce bone differentiation when combined with granules of porous hydroxyapatite with identical pore dimensions. The finding that the biological activity of osteogenin can be restored and delivered by a substratum with defined geometry other than the insoluble collagenous matrix may form the basis of the potential therapeutic application of bone morphogenetic proteins.
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543
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Ma S, Long JP, Bhatnagar RK. Further studies on central actions of nitroglycerin and lack of evidence for nitroglycerin interacting on [3H]clonidine binding sites in cortex membranes. J Pharmacol Exp Ther 1992; 261:1187-94. [PMID: 1318374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Decerebration and transection of the spinal cord totally abolished the hypotensive and tachycardiac responses to i.c.v injection of nitroglycerin (NTG) and reduced the tachycardia induced by i.v. injection of the drug. The hypotensive responses to i.v. injection of sodium nitroprusside were not altered by decerebration. Microinjection of NTG (0.1-1.0 nmol) into anterior hypothalamic medial preoptic area (AH/POA) produced dose-dependent decreases in mean arterial pressure and heart rate, but minimal responses were induced when the same doses of NTG were injected into the rostral ventrolateral medulla. Pretreatment with rauwolscine (2.5 nmol), injected into the AH/POAs, antagonized the depressor responses to NTG when it was administered into the areas or given i.v. However, rauwolscine did not alter the depressor responses induced by i.v. sodium nitroprusside. Prazosin (1.5 nmol) in the AH/POA did not alter the bradycardic effects induced by microinjection of NTG into the areas. (minus)-Epinephrine significantly interacted with alpha-2 adrenoceptor binding sites, but serotonin and NTG did not interact with [3H] clonidine binding sites in cortex membranes. Results suggest that cardiovascular responses after i.v. injection of NTG involve central and peripheral component. AH/POA is one of the central sites involved in the depressor effects of NTG. NTG-induced modulation of noradrenergic transmission appears to stimulate alpha-2 adrenoceptors in the central nervous system, but the drug does not involve direct interaction with alpha-2 adrenoceptors. Hypotensive effects of sodium nitroprusside result from its action at peripheral sites.
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544
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Ma S. [The effects of nitroglycerin on refractory congestive heart failure by intravenous infusion]. ZHONGHUA XIN XUE GUAN BING ZA ZHI 1992; 20:160-2, 195. [PMID: 1289026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Noninvasive hemodynamic and clinical studies were carried out in 24 patients with congestive heart failure refractory to digitalis, diuretics and vasodilators. Nitroglycerin was given by intravenous infusion for 5-7 days. The results showed that the symptoms, signs and hemodynamic parameters were markedly improved. The overall clinical effective rate was 96% and no serious side effect was noted.
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545
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Zhu Z, Shen Y, Zhang M, Chen G, Ma S. [Pharmacological study on spleen-stomach warming and analgesic actions of Aconitum carmichaeli Debx]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1992; 17:238-41, inside backcover. [PMID: 1418555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This study presents an observation of the anti-inflammatory effect of Aconitum carmichaeli decoction on water-immersion stress induced gastric ulcer in mice and 0.6 mol/L HCl induced gastric ulcer in rats. The observation showed that the decoction was resistant to the castor oil induced and Cassia angustifolia leaf induced experimental diarrhea in mice, and also had marked analgesic action. It is thus suggested that Aconitum carmichaeli is useful clinically as a spleen-stomach warming and analgesic agent in traditional Chinese medicine.
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546
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Fang RH, Chen CF, Ma S. A new method for clitoroplasty in male-to-female sex reassignment surgery. Plast Reconstr Surg 1992; 89:679-82; discussion 683. [PMID: 1546080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Sex reassignment surgery has proved to be the best resolution for primary transsexuals. In 1980, Dr. Rubin stated that preservation of the glans to reconstruct the clitoris in male-to-female sex reassignment surgery gave good cosmetic and functional results. In his series, Rubin used the corpus spongiosum as the vascular pedicle of the neoclitoris, but urine leakage is a complication. From 1988 to the present, the dorsal portion of the glans penis with the dorsal neurovascular pedicle has been used here for clitoroplasty in nine male-to-female primary transsexuals. All neoclitorides survived well, with good preservation of light touch and sexual sensation. No urine leakage has occurred. Six patients who were followed reported sexual satisfaction.
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547
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Wang Y, Cheng Z, Gao C, Fu S, Wang S, Fu H, Ye L, Ma S. Molecular cytogenetic study of short arm aberrations in human D, G group chromosomes. CHINESE MEDICAL SCIENCES JOURNAL = CHUNG-KUO I HSUEH K'O HSUEH TSA CHIH 1992; 7:27-31. [PMID: 1421359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Six cases of Dp+/Gp+, 10 cases of D/G translocation, 1 case of supernumerary marker chromosome, and 1 case of Yqs were studied using molecular and cytogenetic techniques. The Ag-NOR frequencies of the Dp+ and Gp+ groups were found to be higher than those of normal controls, while their satellite association frequencies were lower. Autoradiographic silver grains were not significantly distributed along the p+ part of the marker chromosome as revealed by chromosomal in situ hybridization using an rRNA probe. This result differs from our previous report. It is suggested that there might be different mechanisms for the formation of p+ on acrocentric chromosomes. D/G translocation cases were found to have lost their NOR. A study of supernumerary marker chromosomes and Yqs cases suggested that the marker chromosome and Yqs exerted no phenotypic effect. The mechanism of their formation is discussed.
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548
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Zou D, Ma S, Guan R, Park M, Sun L, Aklonis JJ, Salovey R. Model filled polymers. V. Synthesis of crosslinked monodisperse polymethacrylate beads. ACTA ACUST UNITED AC 1992. [DOI: 10.1002/pola.1992.080300118] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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549
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Ripamonti U, Magan A, Ma S, van den Heever B, Moehl T, Reddi AH. Xenogeneic osteogenin, a bone morphogenetic protein, and demineralized bone matrices, including human, induce bone differentiation in athymic rats and baboons. MATRIX (STUTTGART, GERMANY) 1991; 11:404-11. [PMID: 1787832 DOI: 10.1016/s0934-8832(11)80195-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Subcutaneous implantation of xenogeneic demineralized bone matrix does not initiate endochondral bone differentiation. Dissociative extraction in 4 M guanidine-HCl or 6 M urea has shown that the apparent species-specificity of intact bone matrix resides in its insoluble immunogenic component, since there is homology in solubilized osteogenic proteins amongst mammals. To further investigate the species-specificity and cross-species reactivity of bone matrix components, baboon and human demineralized bone matrix (DBM) and bovine osteogenin, purified greater than 50,000-fold and with an apparent molecular mass of 28-42 kilodaltons, were implanted in the subcutaneous space of athymic and euthymic rats and into the rectus abdominis of 16 baboons (Papio ursinus). Baboon DBM was also implanted in athymic and euthymic mice. Alkaline phosphatase activity and histology of implants harvested at day 11 and 30 showed that baboon and human DBM induced endochondral bone differentiation both in athymic rats and baboons. Bovine osteogenin in conjunction with baboon insoluble collagenous matrix induced extensive bone differentiation in athymic rats and baboons. Baboon and human DBM did not induce bone differentiation in euthymic rats and, in athymic mice, baboon DBM failed to induce bone differentiation, determining instead the recruitment of multinucleated giant cells. The results indicate that in rodents bone differentiation induced by intact bone matrix is species specific and that T-cell functions are not a requirement for bone induction, although immunologically competent rats block bone differentiation from xenogeneic matrix. Bone differentiation induced by human DBM in baboons suggests that intact bone matrices may not be species-specific amongst primates.(ABSTRACT TRUNCATED AT 250 WORDS)
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550
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Bowers G, Felton F, Middleton C, Glynn D, Sharp S, Mellonig J, Corio R, Emerson J, Park S, Suzuki J, Ma S, Romberg E, Reddi AH. Histologic comparison of regeneration in human intrabony defects when osteogenin is combined with demineralized freeze-dried bone allograft and with purified bovine collagen. J Periodontol 1991; 62:690-702. [PMID: 1753322 DOI: 10.1902/jop.1991.62.11.690] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A bone-inductive protein, osteogenin, has been isolated from long bones of humans and offers promise as a grafting material. Studies, however, suggest that osteogenin must be combined with a bone-derived matrix in order to initiate bone differentiation. The purpose of this study was to determine if osteogenin combined with demineralized freeze dried bone allograft (DFDBA), a bone-derived matrix, and with a bovine tendon-derived matrix will enhanced regeneration of intrabony defects in humans. The tendon-derived matrix and DFDBA used alone served as controls. The ability of each material to form a new attachment apparatus was evaluated independently in submerged and nonsubmerged environments in 2 patient populations. Lymphocyte testing was performed to assess development of an immune reaction to osteogenin. The most apical level of calculus on the root served as the histologic reference point to measure regeneration. Biopsies were obtained at 6 months and regeneration was measured histomorphometrically by 2 blinded evaluators. Serial sections from 36 submerged defects in 8 patients and 50 nonsubmerged defects in 6 patients were submitted for statistical analysis. Mean results indicate that osteogenin combined with DFDBA significantly enhanced regeneration of a new attachment apparatus and component tissues in a submerged environment. DFDBA plus osteogenin and DFDBA alone formed significantly more new attachment apparatus and component tissues than either the tendon-derived matrix plus osteogenin or the tendon-derived matrix alone in both submerged and nonsubmerged environments. There were no significant differences between the tendon-derived matrix plus osteogenin and the tendon-derived matrix alone in either the submerged or nonsubmerged environment. Osteogenin does not impair normal lymphocyte blastogenesis at 6 months postsurgical challenge.
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