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H Hsieh

Publications and source records attributed to H Hsieh.

At least 19 recordsLinked to original sources
PubMed2001

Towards a full karyotype screening of interphase cells: 'FISH and chip' technology.

Numerical chromosome aberrations are incompatible with normal human development. Our laboratories develop hybridization-based screening tools that generate a maximum of cytogenetic information for each polar body or blastomere analyzed. The methods are developed considering that the abnormality might require preparation of case-specific probes and that only one or two cells will be available for diagnosis, most of which might be in the interphase stage. Furthermore, assay efficiencies have to be high, since there is typically not enough time to repeat an experiment or reconfirm a result prior to fertilization or embryo transfer. Structural alterations are delineated with breakpoint-spanning probes. When screening for numerical abnormalities, we apply a Spectral Imaging-based approach to simultaneously score as many as ten different chromosome types in individual interphase cells. Finally, DNA micro-arrays are under development to score all of the human chromosomes in a single experiment and to increase the resolution with which micro-deletions can be delineated.

Blastomeres↗
PubMed2001

Apoptosis and Fas-ligand expression correlate to the histopathological grade of gastric smooth muscle tumors.

BACKGROUND: Apoptosis is associated with the tumor grade in various types of carcinomas or lymphomas, but less is understood about the association of apoptosis in mesenchymal tumors. In the prior studies, expression of apoptotic regulatory proteins, Bcl-2, Fas and its ligand, Fas-ligand, has been related to apoptotic index (AI) and histopathological grade of tumors. Our study investigated the incidence of apoptosis in gastric smooth muscle tumor and the correlation of the apoptotic index (AI) with the histopathological grade of the tumors. We evaluated the relationship of apoptotic regulatory proteins to the AI and tumor grade. METHODS AND MATERIALS: Using immunohistochemistry and the terminal deoxynucleotidyl transferase (TdT)-mediated digoxigenin-dUTP nick end-labeling (TUNEL) assay, we analyzed the expression of Bcl-2, Fas, Fas-ligand, and AI in 26 cases of gastric smooth muscle tumors. RESULTS: The incidence of greater than 10 apoptotic cells per 10 high-power fields (HPFs) was 73% (19/26 cases). The AI was significantly associated with malignant tumors (P = 0.006) and mitotic counts (P = 0.006) but not with tumor size. Bcl-2, Fas, and Fas-ligand were detected in 13 (50%), 14 (53.8%), and 19 (73%) cases, respectively. Interestingly, Fas-ligand was significantly correlated to malignancy (P = 0.006), mitotic counts (P = 0.006), and AI (P = 0.035) but not to tumor size. Fas expression was significantly associated with high levels of AI (P = 0.014). In contrast, Bcl-2 expression was inversely associated with AI (P = 0.004). Expression of Bcl-2 and Fas did not show a statistically significant correlation with tumor grade, mitotic counts, or tumor size. CONCLUSION: Apoptosis and Fas-ligand expression are statistically correlated to the histopathological grade of gastric smooth muscle tumors. This suggests that detection of apoptotic cells and Fas-ligand expression using the TUNEL assay or immunohistochemistry are useful for the evaluation of the malignant potential of gastric smooth muscle tumors.

Adult↗
PubMed2000

Identification and characterization of an equilibrium intermediate in the unfolding pathway of an all beta-barrel protein.

The guanidinium hydrochloride (GdnHCl)-induced unfolding of an all beta-sheet protein, the human acidic fibroblast growth factor (hFGF-1), is studied using a variety of biophysical techniques including multidimensional NMR spectroscopy. The unfolding of hFGF-1 in GdnHCl is shown to involve the formation of a stable equilibrium intermediate. Size exclusion chromotagraphy using fast protein liquid chromatography shows that the intermediate accumulates maximally at 0.96 m GdnHCl. 1-Anilinonapthalene 8-sulfonate binding, one-dimensional (1)H NMR, and limited proteolytic digestion experiments suggest that the intermediate has characteristics resembling a molten globule state. Chemical shift perturbation and hydrogen-deuterium exchange monitored by (1)H-(15)N heteronuclear single quantum coherence spectra reveal that profound structural changes in the intermediate state (in 0.96 m GdnHCl) occur in the C-terminal, heparin binding region of the protein molecule. Additionally, results of the stopped flow fluorescence experiments suggest that the kinetic refolding of hFGF-1 proceeds through the accumulation of an intermediate at low concentrations of the denaturant. To our knowledge, the present study is the first report wherein an equilibrium intermediate is characterized in detail in an all beta-barrel protein.

Anilino Naphthalenesulfonates↗
PubMed1999

LlaFI, a type III restriction and modification system in Lactococcus lactis.

We describe a type III restriction and modification (R/M) system, LlaFI, in Lactococcus lactis. LlaFI is encoded by a 12-kb native plasmid, pND801, harbored in L. lactis LL42-1. Sequencing revealed two adjacent open reading frames (ORFs). One ORF encodes a 680-amino-acid polypeptide, and this ORF is followed by a second ORF which encodes an 873-amino-acid polypeptide. The two ORFs appear to be organized in an operon. A homology search revealed that the two ORFs exhibited significant similarity to type III restriction (Res) and modification (Mod) subunits. The complete amino acid sequence of the Mod subunit of LlaFI was aligned with the amino acid sequences of four previously described type III methyltransferases. Both the N-terminal regions and the C-terminal regions of the Mod proteins are conserved, while the central regions are more variable. An S-adenosyl methionine (Ado-Met) binding motif (present in all adenine methyltransferases) was found in the N-terminal region of the Mod protein. The seven conserved helicase motifs found in the previously described type III R/M systems were found at the same relative positions in the LlaFI Res sequence. LlaFI has cofactor requirements for activity that are characteristic of the previously described type III enzymes. ATP and Mg2+ are required for endonucleolytic activity; however, the activity is not strictly dependent on the presence of Ado-Met but is stimulated by it. To our knowledge, this is the first type III R/M system that has been characterized not just in lactic acid bacteria but also in gram-positive bacteria.

Amino Acid Sequence↗
PubMed1996

Computerized analysis of fetal heart rate changes after antepartum external cephalic version.

OBJECTIVE: To assess the fetal heart rate (FHR) changes following external cephalic version using a computerized FHR monitor. STUDY DESIGN: We performed 116 external cephalic versions on 106 pregnant women at 36-40 weeks' gestation. Tocolysis (magnesium sulfate) was given to 39 patients (34%). Computerized FHR monitoring was performed for 20-30 minutes before and for 20-30 minutes after the procedure. In addition, we analyzed the results of the FHR tracing obtained during the first 10 minutes following the procedure. RESULTS: External cephalic version was successful in 40% of the patients. In the group of patients who were not treated with magnesium sulfate, FHR variation and the number of accelerations per 10 minutes were significantly reduced during the first 10 minutes following the procedure as compared with those factors on the FHR tracings obtained before or 20-30 minutes following the procedure (P < .05). In the group of patients who were treated with magnesium sulfate, FHR variation and the number of accelerations per 10 minutes were significantly reduced before and 10 minutes after the procedure as compared with the FHR tracings obtained 20-30 minutes following the procedure (P < .05). In both groups the basal FHR was significantly lower during the first 20-30 minutes following the procedure (P < .05). FHR decelerations were observed following the procedure in only two patients. None of the 106 fetuses had a low Apgar score or were admitted to the neonatal intensive care unit. CONCLUSION: External cephalic version appears to be safe for the mother and fetus, although transient FHR changes may occur following the procedure.

Adult↗
PubMed1995

Which birthweight groups contributed most to the overall reduction in the neonatal mortality rate in the United States from 1960 to 1986?

We determined the relative contributions of individual birthweight groups to the reduction in neonatal mortality rate (NMR) of US singleton livebirths from 1960 to 1986, the period during which neonatal intensive care was introduced and became established. Changes in the NMR for each race (non-white/white) and birthweight group were assessed in terms of three components of NMR (1) birthweight-specific neonatal mortality rate (BWS-NMR), (2) birthweight distribution, and (3) the interaction resulting from simultaneous changes in BWS-NMR and birthweight distribution. Overall, NMR decreased from 16.7 per 1000 livebirths in 1960 to 5.5 per 1000 livebirths in 1986. This reduction was achieved mainly by improvements in the BWS-NMRs of all birthweight groups. Neonates who weighted > 1.5 kg at birth were the major contributors to the overall reduction in the NMR; approximately two-thirds of total reduction in NMR between 1960 and 1980 and 52.6% of the total reduction between 1980 and 1986 occurred in the > 1.5 kg birthweight groups. Our study demonstrates that with the introduction of neonatal intensive care, survival of infants with birthweights > 1.5 kg improved markedly and that this improvement accounted for most of the decline in the neonatal mortality rate in the United States from 1960 to 1986. Therefore, in measuring the effectiveness of neonatal intensive care, the assessment should include not only very low birthweight (< 1.5 kg) but all birthweight groups.

Birth Weight↗