Biomedical subjects

Y Hong

Publications and source records attributed to Y Hong.

At least 73 records · Page 4Linked to original sources

PubMed2001

[Clinical study of decompression of optic nerve through combined orbit, ethmoid and sphenoid approach].

OBJECTIVE: To improve the level of diagnosis and treatment of optic nerve trauma at the canalicular segment. METHOD: Fifty-two patients with optic nerve trauma at the canalicular segment received decompression of optic canal through combined orbit, ethmoid and sphenoid approach. RESULT: The visual improvement rate of all 52 patients was 42.3%, 73.9% in 23 patients with secondary optic trauma and 17.2% in 29 patients with primary optic trauma. Patients's vision covered from 0.05 to 0.6 after six months. CONCLUSION: The advantages of decompression of optic nerve through combined orbit, ethmoid and sphenoid approach include easily operation and location, short approach, wide visual field and clear anatomy mark, so it is very safe and suited for those patients with dysplasia and osteosclerosis of ethmoidal or sphenoidal sinus. Orbital CT scan facilitates the diagnosis of optic canal fracture without false positive results. The curative effect is associated with the type of optic nerve trauma and the chance of surgery. Amaurosis shortly after trauma is a dangerous factor of poor prognosis, but it isn't impossible to improve vision if patients receive operation as early as possible.

Adolescent↗

PubMed2000

A comparative structural analysis of the ADF/cofilin family.

Actin-depolymerizing factor (ADF) and cofilin define a family of actin-binding proteins essential for the rapid turnover of filamentous actin in vivo. Here we present the 2.0 A crystal structure of Arabidopsis thaliana ADF1 (AtADF1), the first plant crystal structure from the ADF/cofilin (AC) family. Superposition of the four AC isoform structures permits an accurate sequence alignment that differs from previously reported data for the location of vertebrate-specific inserts and reveals a contiguous, vertebrate-specific surface opposite the putative actin-binding surface. Extending the structure-based sequence alignment to include 30 additional isoforms indicates three major groups: vertebrates, plants, and "other eukaryotes." Within these groups, several structurally conserved residues that are not conserved throughout the entire AC family have been identified. Residues that are highly conserved among all isoforms tend to cluster around the tryptophan at position 90 and a structurally conserved kink in alpha-helix 3. Analysis of surface character shows the presence of a hydrophobic patch and a highly conserved acidic cluster, both of which include several residues previously implicated in actin binding.

Actin Depolymerizing Factors↗

PubMed2000

Rb-independent induction of apoptosis by bovine papillomavirus type 1 E7 in response to tumor necrosis factor alpha.

Bovine papillomavirus type 1 (BPV-1) is a small DNA virus that causes fibropapillomas of the host. BPV-1 has served as the prototype for studies of the molecular biology of the papillomaviruses. BPV-1 efficiently induces anchorage-independent growth and focus formation in murine C127 cells. The transforming properties of BPV-1 primarily reside in two genes, E5 and E6. Each of these genes is sufficient to transform cells. Although no independent transformation activity has been detected for E7, it was shown to be required for full transformation of C127 by BPV-1. We investigated the biological activities of BPV-1 E7 in several assays. Our results indicate that expression of BPV-1 E7 sensitizes cells to tumor necrosis factor alpha (TNF)-induced apoptosis. The TNF-induced apoptosis in E7-expressing cells was accompanied by increased release of arachidonic acid, indicating that phospholipase A(2) was activated. Unlike the E7 proteins from the cancer-related human papillomaviruses, the BPV-1 E7 protein does not associate efficiently with the retinoblastoma protein (pRB) in vitro, nor does it significantly affect the pRB levels in cultured cells. Furthermore, BPV-1 E7 sensitizes Rb-null cells to TNF-induced apoptosis. These studies indicate that BPV-1 E7 can sensitize cells to apoptosis through mechanisms that are independent of pRB.

Animals↗

PubMed2000

An ethylene-induced cDNA encoding a lipase expressed at the onset of senescence.

A cDNA clone encoding a lipase (lipolytic acyl hydrolase) expressed at the onset of petal senescence has been isolated by screening a cDNA expression library prepared from carnation flowers (Dianthus caryophyllus). The cDNA contains the lipase consensus sequence, ITFAGHSLGA, and encodes a 447-amino acid polypeptide with a calculated molecular mass of 50.2 kDa that appears to be a cytosolic protein. Over-expression of the clone in Escherichia coli yielded a protein of the expected molecular weight that proved capable of deesterifying fatty acids from p-nitrophenylpalmitate, tri-linolein, soybean phospholipid, and Tween in both in vitro and in situ assays of enzyme activity. The abundance of the lipase mRNA increases just as carnation flowers begin to senesce, and expression of the gene is also induced by treatment with ethylene. Southern blot analyses of carnation genomic DNA have indicated that the lipase is a single copy gene. The lipase gene is also expressed in carnation leaves and is up-regulated when the leaves are treated with ethylene. Deesterification of membrane lipids and ensuing loss of membrane structural integrity are well established early events of plant senescence, and the expression pattern of this lipase gene together with the lipolytic activity of its cognate protein indicate that it plays a fundamentally central role in mediating the onset of senescence.

Amino Acid Sequence↗

PubMed2000

Requirement of PIG-F and PIG-O for transferring phosphoethanolamine to the third mannose in glycosylphosphatidylinositol.

Many eukaryotic proteins are anchored by glycosylphosphatidylinositol (GPI) to the cell surface membrane. The GPI anchor is linked to proteins by an amide bond formed between the carboxyl terminus and phosphoethanolamine attached to the third mannose. Here, we report the roles of two mammalian genes involved in transfer of phosphoethanolamine to the third mannose in GPI. We cloned a mouse gene termed Pig-o that encodes a 1101-amino acid PIG-O protein bearing regions conserved in various phosphodiesterases. Pig-o knockout F9 embryonal carcinoma cells expressed very little GPI-anchored proteins and accumulated the same major GPI intermediate as the mouse class F mutant cell, which is defective in transferring phosphoethanolamine to the third mannose due to mutant Pig-f gene. PIG-O and PIG-F proteins associate with each other, and the stability of PIG-O was dependent upon PIG-F. However, the class F cell is completely deficient in the surface expression of GPI-anchored proteins. A minor GPI intermediate seen in Pig-o knockout but not class F cells had more than three mannoses with phosphoethanolamines on the first and third mannoses, suggesting that this GPI may account for the low expression of GPI-anchored proteins. Therefore, mammalian cells have redundant activities in transferring phosphoethanolamine to the third mannose, both of which require PIG-F.

Amino Acid Sequence↗

PubMed2000

Molecular basis of competition between HSF2 and catalytic subunit for binding to the PR65/A subunit of PP2A.

We recently identified the existence of a novel interaction between heat shock transcription factor 2 (HSF2) and the PR65/A subunit of protein phosphatase 2A (PP2A) and showed that HSF2 is able to compete with the PP2A catalytic subunit for binding to PR65. To elucidate the mechanistic basis of this competition between HSF2 and catalytic subunit at the molecular level we have sought to characterize sequences within PR65 that are important for interaction with HSF2. The results identify the intra-repeat loop within HEAT repeat 11 of PR65 as critical for interaction with HSF2. Analysis of point mutants within this loop region of PR65 identify lysine 416 as a residue critical for interaction with HSF2. Interestingly, this same lysine residue of PR65 is important for its binding to catalytic subunit. These results suggest that HSF2's ability to interfere with catalytic subunit binding to PR65 is due to competition between HSF2 and catalytic subunit for at least one amino acid residue of PR65, lysine 416. These data support the hypothesis that HSF2 represents a new type of PP2A regulatory protein.

Amino Acid Sequence↗

PubMed2000

Artificial recruitment of Sp1 or TBP can replace the role of IE1 in the synergistic transactivation by IE1 and IE2.

The IE1 and IE2 proteins of human cytomegalovirus transactivate various viral and cellular promoters in a synergistic manner, but the mechanism of their action has not been well elucidated. Here we have examined the IE1-IE2 synergy by artificial recruitment of either Sp1 or TBP to the promoter. We found that in the presence of Sp1, the synergistic effect of IE1 on IE2-mediated transactivation dramatically decreased. Furthermore, a 117-amino acids glutamine-rich fragment of Sp1, which can interact with dTAF(II)110 and hTAF(II)130, was sufficient to replace the role of IE1 in IE1-IE2 synergism. It was also found that TBP recruitment to the promoter markedly decreased the synergistic effect of IE1 on IE2-mediated transactivation. These results suggested that in the context of the synergism between IE1 and IE2, the function of IE1 might overlap with that of Sp1, for example by recruiting the TFIID complex.

Animals↗

PubMed2000

Detection of an RNA-dependent RNA polymerase in mitochondria from a mitovirus-infected isolate of the Dutch Elm disease fungus, Ophiostoma novo-ulmi.

RNA-dependent RNA polymerase (RdRp) activity has been detected in mitochondria from an isolate of Ophiostoma novo-ulmi infected with O. novo-ulmi mitovirus 6 (OnuMV6). The reaction products corresponded to the double-stranded and single-stranded forms of OnuMV6 RNA. Western blot analysis using antibodies raised against a conserved RdRp region has detected a protein of ca. 80 kDa in OnuMV6-infected mitochondria, close to the predicted size of the OnuMV6 RdRp. No RdRp activity or protein was detected in mitochondria from an uninfected O. novo-ulmi isolate. This is the first detection of a virus RdRp in fungal mitochondria and the results are consistent with the use of UGA tryptophan codons in its synthesis.

Ascomycota↗

PubMed2000

Effect of hypoxia on nitric oxide production and its synthase gene expression in rat smooth muscle cells.

It has not been clarified yet as to whether hypoxia and inflammation affect NO synthesis. In this study, we investigated the transcription of inducible nitric oxide synthase (iNOS) mRNA and the production of nitric oxide (NO) in rat smooth muscle cells (SMCs) cultured under hypoxic conditions in the presence and absence of proinflammatory cytokine interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS). We found that hypoxia inhibited the production of NO but did not affect the transcription of iNOS mRNA in rat SMCs treated with IFN-gamma, LPS, or both. These results indicate that O(2) is involved in the regulation of NO synthesis in inflammatory tissues.

Animals↗

PubMed2000

Physical and functional interaction between the HCMV IE2 protein and the Wilms' tumor suppressor WT1.

Human cytomegalovirus (HCMV) is a major renal pathogen in congenitally infected infants and renal allograft recipients. It has been shown that human kidney cells of glomerular, tubular, and vascular origin were all infected by HCMV in vitro. It has previously been demonstrated that the IE2 protein of HCMV directly associates with the zinc finger domain of Egr-1. The zinc finger region of WT1 is a sequence-specific DNA-binding domain which also recognizes the consensus DNA binding site (5'-CGCCCCCGC-3') of Egr-1, thus suggesting a possible interaction between WT1 and IE2. Here we demonstrate that HCMV IE2 binds to the C-terminal region of WT1 containing zinc finger domain in vivo as well as in vitro and that WT1 can inhibit IE2-driven transactivation of the responsive promoter. Our results suggest that WT1 may be able to regulate the functional activity of HCMV IE2. Furthermore, these data may provide new insights into the possible involvement of HCMV in WT1-related pathogeneses.

Animals↗

PubMed2000

Alcohol consumption and plasminogen activator inhibitor type 1: the National Heart, Lung, and Blood Institute Family Heart Study.

BACKGROUND: Plasminogen activator inhibitor type 1 (PAI-1) plays a key role in fibrinolytic activity, which is important for thrombotic cardiovascular events. It has been suggested that moderate alcohol consumption may protect against coronary heart disease and ischemic stroke. However, little is known about the effects of moderate doses of alcohol on PAI-1. METHODS AND RESULTS: We assessed the association between different levels of alcohol consumption and PAI-1 among 1862 participants of the National Heart, Lung, and Blood Institute Family Heart Study. We fitted a regression model, adjusting for anthropometric, metabolic, and lifestyle factors. Individuals in the highest alcohol intake category were leaner, had higher high-density lipoprotein cholesterol levels, smoked more cigarettes, and consumed less dietary fiber compared with never-drinkers. For drinking categories of never-drinkers, ex-drinkers, and current drinkers of 0.1 to 1.4, 1.5 to 4.9, 5.0 to 14.9, and > or =15 g/d of alcohol, multivariate adjusted geometric mean PAI-1 levels among women were 10.77, 9.41, 9.99, 11.21, 11.28, and 16.40 ng/mL, respectively. With similar categories except the top category divided into 15.0 to 29.9 and > or =30 g/d, PAI-1 levels among men were 18.43, 15.77, 15.19, 16.20, 17.27, 24.02, and 29.46 ng/mL, respectively. CONCLUSIONS: These results show that alcohol consumption up to 14.9 g/d is not associated with increased PAI-1, whereas the findings suggest increased PAI-1 with greater alcohol intake.

Adult↗

PubMed2000

Evaluation of fluorescent dyes for the detection of mitochondrial membrane potential changes in cultured cardiomyocytes.

OBJECTIVE: Maintenance of the mitochondrial membrane potential (Deltapsim) is fundamental for the normal performance and survival of cells such as cardiomyocytes, that have a high energy requirement. Measurement of Deltapsim is therefore essential in order to develop an understanding of the molecular mechanisms controlling cardiomyocyte function. Here we have evaluated various potentiometric dyes for their ability to detect alterations of Deltapsim, using flow cytometry and confocal microscopy. METHODS: Primary cultures of cardiomyocytes from neonate rats were treated with mitochondrial uncouplers before or after loading with Rho123, DiOC(6)(3), CMXRos or JC-1, and then analysed by flow cytometry. Apoptotic cells were identified by light scatter and Annexin V staining. RESULTS: The four potentiometric dyes tested were able to discriminate between viable and apoptotic cells. However, only JC-1 was able to detect the collapse of Deltapsim induced by uncouplers of mitochondrial respiration. Confocal microscopic analysis confirmed that JC-1 stained mitochondria in a potential-dependent manner. In contrast, CMXRos stained cardiomyocytes irrespective of alterations in Deltapsim. CONCLUSIONS: We conclude that JC-1 is the optimal dye to use when measuring Deltapsim in cardiomyocytes.

Animals↗

PubMed2000

Molecular characterisation of the Theileria buffeli/orientalis group.

Benign bovine Theileria parasites known as either Theileria buffeli, Theileria orientalis or Theileria sergenti are classified on basis of their morphology, vector specificity, pathogenicity and 18S small subunit ribosomal RNA or major piroplasm protein (MPSP) sequences. Since most isolates have been characterized on only some of these criteria and the existing confusion in nomenclature, an analysis was performed on eight different isolates to combine 18S rRNA data with MPSP data and the results were compared with available biological parameters. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) approach for both genes was used in combination with reverse line blot hybridisation for the 18S rRNA gene. Both MPSP and 18S rRNA genes were cloned and sequenced from parasites displaying aberrant MPSP RFLP profiles. Phylogeny based on published and determined 18S rRNA and MPSP sequences did correlate within the same isolate but there was no obvious correlation between molecular and biological data. Based on these findings, we suggest that the appropriate name for all these parasites is Theileria buffeli. A more specific nomenclature should be assigned when new molecular markers may become available.

Animals↗

PubMed2000

No evidence of linkage between the very-low-density lipoprotein receptor gene and fasting serum insulin or homeostasis model assessment insulin resistance index: the National Heart, Lung, and Blood Institute Family Heart Study.

A major gene effect on the fasting insulin level and insulin resistance has been suggested in previous studies. Several candidate genes for insulin resistance in rare syndromes have been proposed. However, there has been limited success in finding genes for common forms of insulin resistance. There is accumulating evidence of a relationship between insulin resistance and a disturbance of free fatty acid (FFA) metabolism. The very-low-density lipoprotein (VLDL) receptor, which is associated with FFA metabolism, could serve as a possible candidate gene for insulin resistance. We performed linkage analyses between the VLDL receptor gene and fasting insulin and the homeostasis model assessment (HOMA) insulin resistance index (fasting insulin x fasting glucose/22.5) in 1,050 sibpairs participating in the phase II physical examination of the National Heart, Lung, and Blood Institute Family Heart Study (FHS). Data analyses were completed using the SIBPAL component of the SAGE software package (SAGE, Statistical Analysis for Genetic Epidemiology, Version 3.1; Computer program package available from the Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH, 1997). We did not find evidence for linkage of the fasting insulin or the HOMA insulin resistance index with a polymorphic marker at the VLDL locus (P = .316 and .402, respectively). Adjustment of fasting insulin and the HOMA insulin resistance index for the body mass index (BMI) did not change the results (P = .319 and .472, respectively). In conclusion, no evidence was found for a linkage between a locus controlling the fasting insulin level or HOMA insulin resistance index and a VLDL polymorphism in the present study. Additional adjustment of fasting insulin or the HOMA insulin resistance index for the BMI did not change the linkage results significantly.

Blood Glucose↗

PubMed2000

A genetic study of dehydroepiandrosterone sulfate measured before and after a 20-week endurance exercise training program: the HERITAGE Family Study.

Familial aggregation and possible major gene effects were evaluated for the baseline serum dehydroepiandrosterone sulfate (DHEAS) level and the change in DHEAS in response to a 20-week exercise training program in a sample of 481 individuals from 99 Caucasian families who were sedentary at baseline and who participated in the HERITAGE Family Study. Baseline DHEAS levels were not normally distributed, and were therefore logarithmically transformed and adjusted for the effects of age and sex prior to genetic analysis. The DHEAS response to training was computed as the simple difference, post-training minus baseline, and was adjusted for the baseline DHEAS level, age, and sex. Maximal (genetic and familial environmental) heritabilities (using a familial correlation model) reached 58% and 30% for the baseline and the response to training, respectively. Our estimate for the baseline is generally in agreement with previous reports, suggesting that the magnitude of the familial effect underlying this phenotype in these sedentary families is similar to that in the general population. However, segregation analysis showed no evidence for a multifactorial familial component in data for either the baseline or the response to training. Rather, a major additive gene controlling the baseline was found. For the response to training in the complete sample, transmission of the major effect from parents to offspring was ambiguous, but in a subset of 56 "responsive" families (with at least 1 family member whose response to training was greater than 1 standard deviation) this major effect was Mendelian in nature. The putative major genes accounted for 50% and 33% of the variance for the baseline and the response to training, respectively. The novel finding in this study is that the baseline DHEAS level and the change in DHEAS in response to training may be influenced by major gene effects.

Adult↗

PubMed2000

Changes in gait patterns in 10-year-old boys with increasing loads when walking on a treadmill.

This study examined the gait pattern, heart rate and blood pressure in children carrying school bags of 0 (as control), 10, 15 and 20% of their own body weight whilst walking on a treadmill. When compared to the 0% load condition, the 20% load condition induced a significant increase in trunk forward lean, double support and stance duration, and decreased trunk angular motion and swing duration and a prolonged blood pressure recovery time. The 15% load condition induced a significant increase in trunk forward lean and prolonged blood pressure recovery time. No significant difference was found in the measured parameters between the 10 and 0% load conditions. We concluded that back pack weight should not exceed 10% of body weight in 10-year-old boys.

Biomechanical Phenomena↗

PubMed2000

Development and clinical assessment of an artificial cornea.

Keratoprosthesis research has been a gradual, rather fragmentary process with advances being made by isolated groups of researchers. This has arisen partly because of poor funding in the area; research groups which have achieved commercial support have often had constraints upon the full disclosure of their findings. Despite these difficulties there has been real progress over the last decade by several independent groups. This article concentrates upon our own development of a hydrogel core-and-skirt keratoprosthesis, the Chirila KPro, in order to illustrate the scientific and clinical problems common to keratoprosthesis research. Pilot data from a clinical trial is presented and the priorities for future research are discussed.

Animals↗

PubMed2000

Evidence of pleiotropic loci for fasting insulin, total fat mass, and abdominal visceral fat in a sedentary population: the HERITAGE family study.

OBJECTIVE: To examine whether there is a major gene effect on fasting insulin and pleiotropic loci for fasting insulin, total fat mass (FM), and abdominal visceral fat (AVF). RESEARCH METHODS AND PROCEDURES: A major gene hypothesis for fasting plasma insulin levels was assessed using segregation analyses of data on 495 members in 98 normolipidemic sedentary families of white descent who participated in the HERITAGE Family Study. RESULTS: Segregation analyses were performed on insulin adjusted for age, on insulin adjusted for age and FM, and on insulin adjusted for age and AVF. Before adjustment for AVF and FM, a major gene effect on fasting insulin levels was indicated. The putative locus accounted for 54% of the variance under a recessive inheritance pattern, affecting 11% of the sample (i.e., allele frequency = 0.33). However, after adjusting for the effects of AVF or FM, neither a major effect alone nor a multifactorial component alone could be rejected, and support for a major gene was equivocal, i.e., neither the hypothesis of Mendelian tau values or that of the equal tau(s) were rejected and the equal tau model fit the data better than the Mendelian tau model. This pattern (i.e., major gene evidence for insulin before but not after adjustment for AVF or FM) suggests that there is a putative locus with pleiotropic effects on both insulin and FM and another pleiotropic locus for both insulin and AVF. DISCUSSION: Although these data do not directly support an additional major gene for insulin independent of AVF and FM, such support cannot be ruled out because there is still a significant major effect on FM- or AVF-adjusted insulin (albeit the Mendelian nature of this effect is ambiguous).

Abdomen↗