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Biomedical subjects

Y L Hu

Publications and source records attributed to Y L Hu.

At least 37 records · Page 2Linked to original sources
PubMed1997

Usefulness of magnetic resonance imaging early after acute myocardial infarction.

In patients, early after acute myocardial infarction (AMI), rapid magnetic resonance imaging (MRI) techniques have been used to assess left ventricular (LV) structure, global and regional function, infarct artery patency, or contrast uptake individually. We hypothesized that MRI could be used as a comprehensive evaluation of the post-AMI patient, studying all of these parameters in < 1 hour. Twenty-seven patients were studied after first AMI. Complete examinations were performed in 23 patients, 16 with anterior and 7 with inferior wall myocardial infarction, on day 5 +/- 2 after the event. For measurement of LV structure and regional function, a breath-hold segmented k-space gradient echo tagging sequence was used. A fat-suppressed segmented k-space breath-hold sequence was used for coronary artery imaging. MRI contrast-enhanced images during bolus gadoteridol transit through the myocardium were obtained to assess first-pass contrast uptake. No adverse events were noted during the MRI scanning, which was completed in 46 +/- 5 minutes. The LV mass index, end-diastolic and end-systolic volume indexes, and ejection fraction were (mean +/- SD) 107 +/- 13 g/m2, 87 +/- 23 ml/m2, 54 +/- 20 ml/m2, and 39 +/- 12%, respectively. Intramyocardial percent circumferential shortening was 11 +/- 6% at the apex, 14 +/- 4% in the midventricle, and 15 +/- 4% at the base. Flow within all infarct arteries was visualized. Seventeen of 23 patients had regions of reduced contrast uptake on first-pass imaging with mean signal intensity of 47 +/- 24% that of remote regions. In patients with recent AMI, comprehensive assessment of LV structure and function, infarct artery patency, and regional myocardial contrast uptake was safe and feasible with MRI of < 1 hour.

Adult↗
PubMed1997

Effects of shear stress on protein kinase C distribution in endothelial cells.

We studied the effects of shear stress on protein kinase C (PKC) in cultured human umbilical vein endothelial cells by use of a flow channel and a monoclonal antibody (MAb 1.3) that recognizes the PKC beta-isozyme. The fluorescence intensity (FI) of the secondary antibody, crystalline tetramethylrhodamine isothiocyanate, was determined by image analysis. The results on each of five shearing experiments were normalized by using the paired stationary control. After 30-min shearing at 2 N/m2, FI per cell increased to 1.6 times that of control, as did the mean FI per unit cell area. The FI per unit stained area and the stained area/cell area ratio were also increased significantly by shearing. The distribution of immunostaining in each cell was determined for its cortical, cytoplasmic, perinuclear, and nuclear regions. The normalized FI per unit area in all four regions and the stained area/cell area ratio in cortical and cytoplasmic regions were significantly higher in the sheared cells than in control; the increases were greatest in the cortical area. Double staining with rhodamine-phalloidin and MAb 1.3 showed the association of actin with the PKC isozyme in both stationary and sheared cells.

Actins↗
PubMed1996

A comparative study of the risk factors for lung cancer in Guangdong, China.

A case-control study involving 390 lung cancer cases, matched 1:1 with controls, was carried out in Guangdong Province to compare risk factors for different histopathologic types of lung cancer in both sexes. Female and male lung cancers appear to differ in epidemiological characteristics, pathologic types, and risk factors. The 291 lung cancer cases in males were predominantly squamous cell lung carcinoma (squamous cell carcinoma/adenocarcinoma = 1:0.5), whereas the 99 female lung cancer cases were predominantly adenocarcinoma (squamous cell carcinoma/adenocarcinoma = 1:2.7). The age at which lung cancer was first diagnosed was lower for females than for males (P < 0.0001). Single-factor conditional logistic regression analysis showed an association of lung cancer with family history of tumors, family history of lung cancer, history of chronic bronchitis/emphysema, history of tuberculosis, history of other lung disease, smoking, exposure to environmental tobacco smoke (ETS) in the home and in the workplace, being professional drivers, use of oral contraceptives, and consumption of pickled and salted fish (P < 0.05). Further multivariate logistic regression analysis showed that family history of tuberculosis, history of chronic bronchitis/emphysema, family history of tumors, smoking, exposure to ETS in the home and in the workplace, and consumption of pickled and salted fish were independent risk factors for lung cancer. Using log-linear model analysis, it was confirmed that lung cancer had significant interactions with chronic bronchitis/emphysema, exposure to ETS, history of tuberculosis and smoking. Smoking, however, could only explain 1/5 of the incidence of female lung cancers. Family history of lung cancer and the use of oral contraceptives were related to lung cancer in women. Except for a weak relationship with history of chronic bronchitis/emphysema, adenocarcinoma was found to have no association with the other risk factors.

Adult↗
PubMed1996

cis-acting elements and trans-acting proteins in the transcription of chorionic gonadotropin/luteinizing hormone receptor gene in human choriocarcinoma cells and placenta.

We investigated the cis-acting elements and trans-acting proteins responsible for a higher basal rate of transcription of hCG/LH receptor gene in human choriocarcinoma JEG-3 cells compared with normal term pregnancy placenta. Sequential deletion of the 5'-flanking region of the gene revealed that there are three negative control regions (NCRs) designated NCR1 (-1457 to -1373 bp), NCR2 (-1051 to -835 bp), and NCR3 (-480 to -184 bp), and a promoter (-184 to -1 bp). NCR3 was more inhibitory than the other two; nearly 60-70% of the inhibitory activity resides in a sequence between -480 to -276 bp, and the rest resides in the sequence between -276 to -184 bp. Gel mobility shift assays showed that the nuclear extracts from JEG-3 cells contained proteins that form three complexes with NCR1, two with NCR2, and six with NCR3. Many of the proteins that form the complexes in NCR3 are shared with the other two NCRs. Most of the proteins that form these complexes are less abundant in nuclear extracts from JEG-3 cells than in those from placenta. The JEG-3 cell nuclear extracts also contained proteins that form three complexes with the proximal promoter of the hCG/LH receptor gene. These proteins were identified as Ap2, Ap2-like I, and Sp1 from the competition studies with synthetic excess unlabeled Ap2, Sp1, and CTF/NF1 consensus oligodeoxynucleotides and/or supershift in gel mobility assays with anti-Ap2 antibody. Although the JEG-3 cell nuclear extracts contained abundant Ap2-like protein I and low levels of Ap2 and Sp1 proteins, the placental nuclear extracts contained low levels of Ap2-like protein I and very low to nondetectable levels of Ap2 and Sp1 proteins. Deoxyribonuclease I footprinting revealed that the nuclear extracts from JEG-3 cells and placent protected the -116 to -93 bp and -65 to -45 bp regions in the proximal promoter of the hCG/LH receptor gene that contain Sp1 and Ap2 binding sites, respectively. However, the nuclear extracts from placenta only partially protected these regions, which is consistent with lower levels of proteins that bind to the proximal promoter of the gene. In summary, we conclude that the presence of low levels of proteins that bind to the NCRs and the high levels of proteins, especially Ap2-like I, that bind to the proximal promoter can potentially explain higher transcription of the hCG/LH receptor gene in JEG-3 cells compared with that in normal term pregnancy human placenta.

Adaptor Protein Complex 2↗
PubMed1996

[An epidemiological analysis on the relationship between motorization and traffic mortality in China].

In order to explore the road accident which brings about a threat against residents' life. We applied motorized extent of city (MEC, the rate per 1,000 persons possessing the number of vehicles), level of traffic safety (LTS, the mortality rate per 10,000 registered vehicles), level of personal safety (LPS, the mortality rate per 100,000 persons) to evaluate the relationship between secular trend of motorization and traffic mortality in China. Although increased by 100 times from 1949 to 1992, MEC was considered rather low in the whole country (MEC = 11.2%). When MEC was progressing while LPS was decreasing year after year, LTS has been improved since the late 1970s. The best records of MEC and LTS were noticed in Beijing and the best LPS was in Inner Mongolia. Throughout the 30 administrative areas, LPS has taken a favourable turn, while MEC and LTS abtained distinct improvement in certain areas. Thus one's personal safety is affected by both the synergism of motorization and the road safety level.

Accidents, Traffic↗
PubMed1996

[An new index to evaluate the elderly health care-geracomia effect index].

This paper introduced a new index--geracomia effect index (GEI) which is expressed by the ratio of survival years of the elderly after their retirement to the expected survival years in order to evaluate the health care service to the elderly. The application of this index was discussed using the mortality data of cardiovascular diseases of a city from 1983 to 1994. The results showed that coronary heart disease, pulmonary heart disease and cerebrovascular disease had a stable influence on the survival years of the elderly during this period while the negative effect of diabetes had been weaken with the calendar years. However, myocardial infarction had begun to threaten the younger groups. The author realized that it needs further practice to make the index applicable.

Aged↗
PubMed1995

[A case-control study on the risk factors of lung cancer in Guangdong].

A case-control study on interaction among the risk factors of primary lung cancer with 390 matched pairs was carried out in Guangdong from 1990 to 1993. The subjects of study were the in-patients with primary lung cancer (age 32-78), which consisted of 171 cases of primary lung squamous cell cancer (L. S), 138 cases of primary lung adenocarcinoma (L. A), and 81 cases of other pathological type (L. S:L. A = 1:0.8). Primary lung squamous cell cancer accounted for the majority (51.55%) of 291 male cases (L. S:L. A = 1:0.5). Primary lung adenocarcinoma made up the majority (57.57%) of 99 female cases (L. S:L. A = 1:2.7). Single factor conditional logistic regression analysis showed that the occurrence of lung cancer was closely associated with history of chronic bronchitis, emphysema, pulmonary tuberculosis and other pulmonary diseases (OR = 2.9-3.6, chi 2 = 13.52-37.55, P < 0.01) other risk factors were smoking, passive smoking from spouse or in the working place and family history of tumour (OR = 2.7-3.6, chi 2 = 8.53-33.15, P < 0.01). Driver, taking oral contraceptive, liking pickles or salted fish and bad ventilation in kitchen could be the risk factors of lung cancer (OR = 1.3-3.0, chi 2 = 4.78-5.0, P < 0.05). Further multiple conditional logistic regression analysis turned out that history of chronic bronchitis, emphysema, pulmonary tuberculosis, smoking, family history of tumour, passive smoking from spouse or in the working place, liking pickles were the independent risk factors of lung cancer (OR = 1.7-3.5). In search of the interaction between lung cancer and the risk factors which included history of chronic bronchitis, emphysema, pulmonary tuberculosis, smoking and passive smoking, a loglinear model analysis was performed. The results revealed that there was significant interaction between two factors in one-stage analysis. Although the interaction existed between chronic bronchitis and tuberculosis, chronic bronchitis and smoking or passive smoking, tuberculosis and passive smoking in the meantime, it had not attained the level of significance among three or more factors (including the principal effect of lung cancer) in two-stage analysis (chi 2 = 1.31-2.27, P > 0.13), and therefore the interaction of the former was not affected by the effects of the latter as yet.

Adenocarcinoma↗
PubMed1994

Protein crystallization in space.

The microgravity environment of space is an ideal place to study the complicated protein crystallization process and to grow good-quality protein crystals. A series of crystal growth experiments of 10 different proteins was carried out in space on a Chinese re-entry satellite FSW-2 in August, 1992. The experiments were performed for about two weeks at a temperature of 18.5 +/- 0.5 degrees C using a tube-like crystallization apparatus made in the Shanghai Institute of Technical Physics, Academia Sinica. More than half of 48 samples from 6 proteins produced crystals, and the effects of microgravity on protein crystal growth were observed, especially for hen-egg white lysozyme and an acidic phospholipase A2 from the venom of Agkistrodon halys Pallas. Analyses of the crystallization of these two enzymes in this mission showed that the microgravity environment in space may be beneficial to improve size, external perfection, morphology, internal order, and nucleation of protein crystals. Some of these positive microgravity effects were also demonstrated by the growth of protein crystals in gelled solution with the above two enzymes. A structural analysis of the tetragonal lysozyme crystal grown in space is in progress.

Ancrod↗
PubMed1994

Protein crystal growth in microgravity.

Protein crystal growth is quite important for the determination of protein structures which are essential to the understanding of life at molecular level as well as to the development of molecular biotechnology. The microgravity environment of space is an ideal place to study the complicated protein crystallization and to grow good-quality protein crystals. A number of crystal-growth experiments of 10 different proteins were carried out in August, 1992 on the Chinese re-entry satellite FSW-2 in space using a tube crystallization equipment made in China. A total of 25 samples from 6 proteins produced crystals, and the effects of microgravity on protein crystal growth were observed, especially for an acidic phospholipase A2 and henegg-white lysozyme which gave better crystals in space than earth-grown crystals in ground control experiments. The results have shown that the microgravity in space favors the improvement of the size, perfection, morphology and internal order of the grown protein crystals.

Crystallization↗
PubMed1994

[Effect of combined chemotherapy against human intestinal nematode eggs].

The effect of a combination of albendazole and mebendazole was evaluated by stool examination in 7 patients with Ascaris lumbricoides eggs, 7 patients with Trichuris trichiura eggs and 9 patients with hookworm eggs. Albendazole and mebendazole were given at 300 mg and 375 mg, respectively. Both drugs were divided into 3 parts, one part b. id., and given in 1.5 days. The fecal eggs turned negative in all the patients with Ascaris infection in 3 days, while the fecal eggs were negative in all patients with Trichuris or hookworm infection in 5 days. The development rates of the eggs were remarkably lower post-treatment than pre-treatment. It was found that the ovicidal rates in human ascariasis, trichuriasis and ancylostomiasis were 98.8%, 100% and 100%, respectively on the second day following the initiation of treatment. The results showed that the worm-repelling and ovicidal effect of the combined chemotherapy was more evident.

Adolescent↗
PubMed1993

Human monocyte colony-stimulating factor stimulates the gene expression of monocyte chemotactic protein-1 and increases the adhesion of monocytes to endothelial monolayers.

The stimulation of the human umbilical vein endothelial cell (HUVEC) with recombinant human monocyte-derived colony-stimulating factor (MCSF) increased the gene expression of monocyte chemotactic protein (MCP-1). Northern blot analysis indicated that 50 U/ml of MCSF is the optimal concentration for this effect. The elevation of MCP-1 mRNA started as early as 1 h after stimulation and was maintained for at least 8 h. An increased MCP-1 level in MCSF-treated HUVEC was also demonstrated at the protein level by immunocytochemical staining using a polyclonal MCP-1-specific antibody. HUVEC activated by 50 U/ml of MCSF for 5 h showed a stronger immunofluorescence staining than control cells. Micropipette separation of THP-1 monocytes from HUVEC showed that the activation of both THP-1 and endothelium by MCSF led to an increase in the separation force by more than three times (36.2 +/- 6.7 x 10(-4) vs. 9.6 +/- 3.6 x 10(-4) dyn). An increased adhesiveness was also observed after MCSF activation of peripheral blood monocytes and HUVEC (16.7 +/- 2.7 x 10(-4) vs. 5.2 +/- 0.9 x 10(-4) dyn). The increased adhesive force in both systems was blocked by the use of anti-MCP-1 (5.5 +/- 0.8 x 10(-4) and 6.8 +/- 1.1 x 10(-4) dyn). Similar results were obtained in experiments in which only HUVEC, but not monocytes, were activated by MCSF. This increased adhesion of untreated monocytes to MCSF-activated HUVEC was also blocked by the addition of anti-MCP-1. In contrast, experiments in which only THP-1 or peripheral blood monocytes, but not HUVEC, were treated with MCSF did not show a significant increase of adhesion between these cells. These results indicate that MCSF augments monocyte-endothelium interaction primarily by its action on the endothelial cell and that this function is probably mediated through an increased expression of MCP-1. The MCSF/MCP-1-dependent adhesive mechanism might be operative in the arterial wall in vivo to lead to the trapping of the infiltrated monocyte-macrophage in the subendothelial space during atherogenesis.

Antibodies↗
PubMed1993

Interaction between HMG proteins (1 + 2) and the negative regulatory region 1 (NCR1) in the 5'-flanking sequence of the human beta-globin gene.

The pattern of high mobility group proteins 1 and 2 (HMG1,2) interaction with the 5'-flanking sequence of the human beta-globin gene has been analyzed by scanning tunnelling microscopy (STM). A 200 bp negative regulatory region in the 5'-flanking sequence of the human beta-globin gene can be folded by HMG proteins 1 and 2 into a circular structure (diameter 70 +/- 6 A) with a linear tail which seems to be a left-handed double helix structure.

Base Sequence↗
PubMed1993

Binding of HMG proteins to the 5'-flanking sequence of human beta-globin gene.

Our previous studies have identified that there are at least three regulatory regions (two negative regions and one positive region) in the 5'-flanking sequence of human beta-globin gene (-610 to +1 bp). The binding of HMG proteins to both negative regulatory regions was examined by the gel mobility shift and DNase I protection assays. In gel mobility shift assay, we observed that HMG proteins 1 and 2 could bind to both negative regulatory regions (NCR1 and NCR2). Using the gel shift competition assay, we identified that the binding proteins between the two regions are different from each other. DNase I protection analysis shows that HMG proteins 1 and 2 only bind to one site (between -560 and -533 bp) in NCR1. However, two protected regions can be detected in NCR2, one between -272 and -252 bp relative to the cap site, the other between -306 and -329 bp. We also observed that HMG proteins 14 and 17 could not bind to both negative regions, so it seems that HMG proteins 1 and 2 may play an important role in the regulation of beta-globin expression through DNA-protein interaction or through protein-protein interaction.

Animals↗
PubMed1991

A new model to account for the order in which enantiomers of alkylarylcarbinols elute from a Pirkle chiral HPLC column: preparation, absolute stereochemistry, and chromatographic properties of (+)-1,2-benzocyclononen-3-ol and (+)-1,2-benzocyclodecen-3-ol.

Samples enriched in (-)- and (+)-1,2-benzocyclononen-3-ol were prepared by microbially mediated reactions. An enriched sample of (+)-1,2-benzocyclodecen-3-ol was prepared by fractional crystallization of the diastereoisomeric camphanates, followed by hydrolysis. The absolute stereochemistry of both alcohols was established by chemical transformations. The elution order of their enantiomers from a chiral Pirkle HPLC column [(R)-N-(3,5-dinitrobenzoyl)phenyl glycine ionically bound to gamma-aminopropyl silanized silica] was determined. The information in conjunction with other data was used to formulate a rule to predict the configuration of an enantiomer of an alkylarylcarbinol from its elution order from this column.

Chromatography, High Pressure Liquid↗
PubMed1991

Transformation by carboxyl-deleted Myb reflects increased transactivating capacity and disruption of a negative regulatory domain.

Carboxyl-truncated forms of the product of the c-myb proto-oncogene (Myb) are encoded by the v-myb oncogene, the rearranged c-myb genes of certain murine cell lines and a transforming recombinant c-myb retrovirus. We report here an examination of the abilities of a series of carboxyl deletions of Myb to transform hemopoietic cells. Increasing degrees of truncation resulted in increasing transforming capacity until the deletions removed the region responsible for transactivation by Myb. Because the effects of these deletions on transformation paralleled their previously described effects on the transactivating capacity of Myb but did not correlate with their ability to repress transcription, our results imply that removal of a domain which negatively regulates transactivation is responsible for oncogenic activation of carboxyl-truncated forms of Myb. Moreover, these data support the view that activated forms of myb transform by increasing and/or deregulating the expression of other genes.

Animals↗