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Biomedical subjects

X Gu

Publications and source records attributed to X Gu.

At least 109 records · Page 6Linked to original sources
PubMed2000

[The effects of EGF, TGF-beta and insulin on the growth of rabbit's skeletal muscle satellite cell].

OBJECTIVE: To investigate the effects of epithelium growth factor (EGF), transforming growth factor-beta(TGF-beta) and insulin on the growth of cultured rabbit's skeletal muscle satellite cells. METHODS: After treatment with EGF, TGF-beta and insulin, MTT method was used to study the proliferation of the cells. RESULTS: EGF and insulin could promote the growth of the satellite cells more significantly than that of TGF-beta. CONCLUSION: It implied that there was a close relationship between the effects of three agents and the regeneration of injured muscles. This kind of positive effect appeared in a dose- and time-dependent manner.

Animals↗
PubMed2000

[Effect of green and yellow vegetables on serum carotenoid in children].

OBJECTIVE: To assay the effect of green and yellow vegetables on serum carotenoid concentration and its relation to serum retinol level in children. METHODS: A ten-week green and yellow vegetable intervention study was conducted in children aged 5.3 to 6.4 years of two classes in a kindergarten in Tai'an City of Shandong Province in early September 1996, one class of light-colored vegetable supplemented with daily 193 grams of light colored vegetables, such as cabbage, Chinese cabbage, potato, cucumber, cauliflower and turnip, and 56 grams of yellow-green vegetables, such as spinach, Chinese chive, carrots and red yams; and the other one of yellow-green vegetables with daily 238 grams of yellow-green vegetables and 34 grams of light colored vegetables, both without change in regular diet. Venous blood specimens were collected before and after the experiment from each of the subjects. Serum retinol and carotenoid were determined with high performance liquid chromatography. RESULTS: Serum level of carotenoid, including all-trans-beta-carotene, cis-beta-carotene, cryptoxanthin and lutein were significantly higher after intervention in yellow-green vegetable group, as compared to their baseline levels. However, in the light-colored vegetable group, all those components, including all-trans-beta-carotene, 13-cis-beta-carotene and lutein, decreased significantly after intervention, as compared with those at their baseline levels. Serum carotene level correlated significantly with that of retinol, and their coefficient of correlation was greater in the winter than in the autumn. CONCLUSION: Carotenoid nutrition status can be improved by supplementation of green and yellow vegetables.

Carotenoids↗
PubMed2000

[A cost-benefit evaluation of neonatal screening for phenylketonuria and congenital hypothyroidism].

OBJECTIVE: In order to make the best use of health care resources, to achieve the maximal social and economic benefits and to lay a foundation for popularizing neonatal screening for phenylketonuria (PKU) and congenital hypothyroidism (CH), a cost-benefit analysis of the screening program was conducted. METHODS: Cost for and benefit gained from screening were calculated according to the average incidence of two diseases recommended by the Ministry of Health, mean charge for neonatal screening, sampling extraction of medical history and data published in national economic statistics. RESULTS: The cost of neonatal screening, treatment for PKU with low phenylalanine milk powder and follow up, the total add up to 128 793 Yuan However the direct and indirect financial benefits is 481 263 Yuan, ratio of cost to benefit was 1:3.7. The cost of neonatal screening for CH is 129 175 Yuan. However the financial benefits including the money saved in treatment, nursing care, special education and the loss of income avoided is 468 470 Yuan, ratio of cost to benefit was 1:3.6. CONCLUSION: Neonatal screening for PKU and CH in this country reflects a better economic and social benefit and merits further popularization.

Congenital Hypothyroidism↗
PubMed2000

[The expressions of transcription factor c-fos mRNA and its protein in the burn wound of rats].

OBJECTIVE: To investigate the rule of the expression in different time points of wound tissue transcription factor c-fos mRNA and its protein after burn, so as to explore the role of c-fos in the initiation of burn wound injury and repairing. METHODS: Male Wistar rats were inflicted with partial thickness scalding of 30% TBSA on the back. In situ hybridization and immunohistochemical methods were used to evaluate the characteristics and pattern of the changes in the expressions of the c-fos mRNA and its protein in normal skin and in the wounded skin at 3 h, 6 h, 1 d, 3 d, 7 d and 14 d postburn, respectively. RESULTS: It was found by light microscopy (LM) that c-fos mRNA and its protein could be found expressed in normal skin and obviously increasingly expressed in wounded skin. The expression of fos protein reached peak level at 3 postburn hour (PBH) and that of its mRNA at 6 PBH. CONCLUSION: The expression of c-fos mRNA and its protein could be induced during burn injury. But the postburn increase in the expression of its gene appeared later than that of its protein, suggesting that the early-appeared fos protein acted through its post-translational modification of preexisting fos molecule.

Animals↗
PubMed2000

[Impacts of clinicopathologic parameters on lymphatic metastasis of oral squamous cell carcinoma].

OBJECTIVE: To evaluate the effects of clinicopathologic parameters on lymphatic metastasis of oral squamous cell carcinoma. METHODS: One hundred and ninety-three patients who underwent therapy in our department were included in this study. Ten parameters (T and N stages, location, patterns of invasion, thickness, lymphocyte infiltration, karyokinesis count, degrees of differentiation, degrees of cell keratinization and nuclear polymorph) were evaluated to determine their effects on lymphatic metastasis of oral carcinoma using univariate and multivariate analysis. RESULTS: By using the univariate analysis, five parameters (T and N stage, pattern and depth of invasion, lymphocyte infiltration) showed significant impacts on pathologic nodal metastasis. From multivariate analysis, however, only patterns of invasion were independent predictors of metastasis. Also, patterns of invasion were the only significant factors that influence the post-operative metastasis besides pattern of neck treatment. CONCLUSION: The pattern of invasion is the most important parameter that influences the metastasis of oral squamous cell carcinoma.

Adult↗
PubMed2000

[Studies on Euphorbia fischeriana diterpenoide lactones inhibitory effect on human tumor cells in vitro].

In this paper, two diterpenoide lactones 16-hydroxypseudojolkinolide B and jolkinolide B were isolated from Euphorbia fischeriana Steud. They showed inhibitory effect on human tumor cells both the K562 cell and CNE2 cell and significant dose-effect relationship. The IC50 values of 16-hydroxypseudojolkinolide B on the two human tumor cells were near to that of ADM's.

Antineoplastic Agents, Phytogenic↗
PubMed1999

The mechanism of pseudouridine synthase I as deduced from its interaction with 5-fluorouracil-tRNA.

tRNA pseudouridine synthase I (PsiSI) catalyzes the conversion of uridine to Psi at positions 38, 39, and/or 40 in the anticodon loop of tRNAs. PsiSI forms a covalent adduct with 5-fluorouracil (FUra)-tRNA (tRNA(Phe) containing FUra in place of Ura) to form a putative analog of a steady-state intermediate in the normal reaction pathway. Previously, we proposed that a conserved aspartate of the enzyme serves as a nucleophilic catalyst in both the normal enzyme reaction and in the formation of a covalent complex with FUra-tRNA. The covalent adduct between FUra-tRNA and PsiSI was isolated and disrupted by hydrolysis and the FUra-tRNA was recovered. The target FU39 of the recovered FUra-tRNA was modified by the addition of water across the 5,6-double bond of the pyrimidine base to form 5,6-dihydro-6-hydroxy-5-fluorouridine. We deduced that the conserved aspartate of the enzyme adds to the 6-position of the target FUra to form a stable covalent adduct, which can undergo O-acyl hydrolytic cleavage to form the observed product. Assuming that an analogous covalent complex is formed in the normal reaction, we have deduced a complete mechanism for PsiS.

Fluorouracil↗
PubMed1999

Characterization of ESE-2, a novel ESE-1-related Ets transcription factor that is restricted to glandular epithelium and differentiated keratinocytes.

Epithelial cell differentiation is tightly controlled by distinct sets of transcription factors that regulate the expression of stage-specific genes. We recently isolated the first epithelium-specific Ets transcription factor (ESE-1). Here we describe the characterization of ESE-2, a second epithelium-restricted ESE-1-related Ets factor. Like ESE-1, ESE-2 is induced during keratinocyte differentiation. However, whereas ESE-1 is expressed in the majority of epithelial cell types, ESE-2 expression is restricted to differentiated keratinocytes and glandular epithelium such as salivary gland, prostate, mammary gland, and kidney. In contrast to ESE-1, full-length ESE-2 binds poorly to DNA due to the presence of a negative regulatory domain at the amino terminus. Furthermore, although ESE-1 and the amino-terminally deleted ESE-2 bind with similar affinity to the canonical E74 Ets site, ESE-2 and ESE-1 differ strikingly in their relative affinity toward binding sites in the c-MET and PSMA promoters. Similarly, ESE-1 and ESE-2 drastically differ in their ability to transactivate epithelium-specific promoters. Thus, ESE-2, but not ESE-1, transactivates the parotid gland-specific PSP promoter and the prostate-specific PSA promoter. In contrast, ESE-1 transactivates the keratinocyte-specific SPRR2A promoter Ets site and the prostate-specific PSMA promoter significantly better than ESE-2. Our results demonstrate the existence of a unique class of related epithelium-specific Ets factors with distinct functions in epithelial cell gene regulation.

Alternative Splicing↗
PubMed1999

[Evaluation on the nutritional status of carotenoid in healthy elder people].

The possible relations between carotenoid status and their health indicators were investigated in an elderly group aged 60-75 years. Fasting serum samples were taken from 41 healthy subjects (20 men and 21 women). The concentrations of carotenoids and vitamin A of serum samples were assayed by HPLC. The results showed that vitamin A level of seven subjects was lower than 0.3 mg/L. Lutein and Zeaxanthin were the predominant carotenoids in serum. The concentration of total carotenoids had inverse correlations with blood glucose, serum cholesterol and triglyceride, and blood pressure. Carotenoids were inversely and significantly correlated with diastolic pressure and body mass index.

Aged↗
PubMed1999

Vascular endothelial growth factor signals endothelial cell production of nitric oxide and prostacyclin through flk-1/KDR activation of c-Src.

Vascular endothelial growth factor (VEGF) is a potent endothelial cell-specific mitogen that promotes angiogenesis, vascular hyperpermeability, and vasodilation by autocrine mechanisms involving nitric oxide (NO) and prostacyclin (PGI(2)) production. These experiments used immunoprecipitation and immunoassay procedures to characterize the signaling pathways by which VEGF induces NO and PGI(2) formation in cultured endothelial cells. The data showed that VEGF stimulates complex formation of the flk-1/kinase-insert domain-containing receptor (KDR) VEGF receptor with c-Src and that Src activation is required for VEGF induction of phospholipase C gamma1 activation and inositol 1,4,5-trisphosphate formation. Reporter cell assays showed that VEGF promotes a approximately 50-fold increase in NO formation, which peaks at 5-20 min. This effect is mediated by a signaling cascade initiated by flk-1/KDR activation of c-Src, leading to phospholipase C gamma1 activation, inositol 1,4,5-trisphosphate formation, release of [Ca(2+)](i) and nitric oxide synthase activation. Immunoassays of VEGF-induced 6-keto prostaglandin F(1alpha) formation as an indicator of PGI(2) production revealed a 3-4-fold increase that peaked at 45-60 min. The PGI(2) signaling pathway follows the NO pathway through release of [Ca(2+)](i), but diverges prior to NOS activation and also requires activation of mitogen-activated protein kinase. These results suggest that NO and PGI(2) function in parallel in mediating the effects of VEGF.

Animals↗
PubMed1999

Quantitative analyses of neurons projecting to primary motor cortex zones controlling limb movements in the rat.

The objective was to determine if projections of single neurons to primary motor cortex preferentially terminate in several efferent zones that could form synergies for the execution of limb movements. Intracortical microstimulation was used to identify zones evoking hip flexion (HF), elbow flexion (EF), and both plantarflexion (PF) and dorsiflexion (DF) about the ankle. Histological examination showed that the zones from which some movements were evoked extended beyond the agranular cortex into granular cortex. Fluorogold, Fast blue, and propridium iodide or rhodamine-labeled dextran were injected into three of these four efferent zones in each rat. There was a virtual absence of multiple-labeled cells despite having an intermingling of different-colored cells of which 15% in frontal cortex were less than 1.2 mm away from a neighboring neuron that projected to a different efferent zone. This suggests that single neurons projecting to the motor cortex do not hard-wire specific synergies but rather project to single efferent zones in order to offer the greatest degree of freedom for the generation of movements. The distribution of ventral posterolateral and ventrolateral thalamic nucleus labeling depended on whether the injections were in granular or agranular cortex. Conversely, frontal cortex projections to motor efferent zones were made irrespective of their location in either granular or agranular cortex and thereby supporting their presumed role in the control of movements. Hindlimb motor cortex injections yielded retrograde labeling that extended into the more localised distribution of frontal cortex neurons retrogradely labeled from forelimb injections. This may allow hindlimb movements to be synchronized by forelimb movements during walking on challenging terrain.

Animals↗
PubMed1999

New device for closure of muscular ventricular septal defects in a canine model.

BACKGROUND: Repair of muscular ventricular septal defects (MVSDs) has always been challenging to the surgeon. Long-term morbidity and mortality are significantly increased if the defects are closed via left ventriculotomy or if they are associated with other complex congenital anomalies. The purpose of this study was to close MVSDs with the Amplatz ventricular septal defect device. This device is constructed from 0.004-in nitinol wire mesh filled with polyester fibers. It is retrievable, repositionable, self-centering, and of low profile. METHODS AND RESULTS: MVSDs were created with the help of a sharp punch in 10 dogs. The location of the defects was anterior muscular (n=3), midmuscular (n=3), apical (n=3), and inlet muscular (n=1). The diameter of the defects ranged from 6 to 14 mm. All defects were closed in the catheterization laboratory. The device was placed with the help of transesophageal echocardiography and fluoroscopy. A 7F sheath was used to deploy the device from the right ventricular side in 8 and the left ventricular side in 2 dogs. Placement was successful in all animals. The complete closure rate was 30% (3/10) immediately after placement and 100% at 1-week follow-up. Pathological examination of the heart revealed complete endothelialization of the device in dogs killed after 3 months. CONCLUSIONS: The Amplatz ventricular septal defect device appears highly efficacious in closing MVSDs. The advantages include a small delivery sheath, complete retrievability before release, and the fact that it is self-centering and self-expanding, thereby making it an attractive option in smaller children.

Alloys↗
PubMed1999

Solution structure of the major alpha-amylase inhibitor of the crop plant amaranth.

alpha-Amylase inhibitor (AAI), a 32-residue miniprotein from the Mexican crop plant amaranth (Amaranthus hypochondriacus), is the smallest known alpha-amylase inhibitor and is specific for insect alpha-amylases (Chagolla-Lopez, A., Blanco-Labra, A., Patthy, A., Sanchez, R., and Pongor, S. (1994) J. Biol. Chem. 269, 23675-23680). Its disulfide topology was confirmed by Edman degradation, and its three-dimensional solution structure was determined by two-dimensional 1H NMR spectroscopy at 500 MHz. Structural constraints (consisting of 348 nuclear Overhauser effect interproton distances, 8 backbone dihedral constraints, and 9 disulfide distance constraints) were used as an input to the X-PLOR program for simulated annealing and energy minimization calculations. The final set of 10 structures had a mean pairwise root mean square deviation of 0.32 A for the backbone atoms and 1.04 A for all heavy atoms. The structure of AAI consists of a short triple-stranded beta-sheet stabilized by three disulfide bonds, forming a typical knottin or inhibitor cystine knot fold found in miniproteins, which binds various macromolecular ligands. When the first intercystine segment of AAI (sequence IPKWNR) was inserted into a homologous position of the spider toxin Huwentoxin I, the resulting chimera showed a significant inhibitory activity, suggesting that this segment takes part in enzyme binding.

Amino Acid Sequence↗
PubMed1999

The alpha v beta 6 integrin induces gelatinase B secretion in colon cancer cells.

In human cancers, the co-operative role between cell-adhesion receptors and proteases capable of degrading matrix barriers remains poorly understood. We have previously reported that the epithelium-restricted integrin alpha(v)beta6 becomes highly expressed in colon cancer compared with normal mucosa and that heterologous expression of alpha(v)beta6 in colon cancer cells is associated with enhanced cell growth. Herein, we report that alpha(v)beta6 expression in colon cancer cells leads to a relative increase in secretion of the matrix metalloproteinase gelatinase B over its respective inhibitor and that this secretion parallels the level of cell-surface beta6 expression. The alpha(v)beta6-mediated gelatinase B secretion is associated with increased proteolysis of denatured collagen at the cell surface, and inactivation of gelatinase B in beta6-expressing tumour cells inhibits cell spreading and proliferation within 3-dimensional collagen matrices. Our findings suggest that alpha(v)beta6-mediated gelatinase B secretion is important in the progression of human colon cancer.

Antigens, Neoplasm↗
PubMed1999

A new technique for sizing of atrial septal defects.

This article evaluates a new compliant balloon catheter for sizing of Atrial Septal Defects (ASDs) in vitro and in vivo using X-ray and echo measurements. A phantom consisting of a plastic plate with 17 circular holes varying from 8 to 30 mm was used to determine the accuracy of the measurements. The catheter has a 7 Fr shaft with a double lumen. The balloon is made from a 0.002" plastic membrane. Four platinum marker bands on the shaft of the catheter allow radiographic measurements. The balloon catheter was placed through various holes of the phantom and inflated with 38% contrast medium. X-ray measurement by video and cine recording were performed and compared with the true measurement of the model. The study was carried out in a double blind fashion. For echo measurements, the plastic model was immersed in a water bath. The balloon was inflated with water and measured in a long-axis view. The actual diameters were compared with the measurements obtained by video, cine, and echo recordings. One young pig with a surgically created ASD was used for in vivo measurement. The balloon catheter was passed through the ASD over an exchange wire, inflated with diluted contrast medium until a waist was observed, which was measured by video and cine techniques. The animal was euthanized, and the defect was measured by a tapered measuring probe. The difference between the actual size and measurements obtained by video recordings was 0.54 +/- 0.30 mm, by cine 0.62 +/- 0.20 mm, and by echo measurements 0.60 +/- 0.43 mm. All measurements were less than 1 mm in error except for four measurements (<1.5 mm). A strong correlation was present between each two groups (r = 0.99, P < 0.0001). In the in vivo study, the size of the video and cine recordings (14.2 and 13.9 mm, respectively) were very closer to the actual size (14 mm) as measured by a probe in the postmortem specimen. The new balloon catheter provides a more rapid and precise determination of the stretched diameter of atrial septal defects. It eliminates the error of pulling a catheter through the communication. This new technique should be of benefit to all investigators using septal occlusion devices and will facilitate the selection of the properly sized Amplatzer septal occluder.

Animals↗
PubMed1999

New self-expanding patent foramen ovale occlusion device.

Our purpose was to evaluate a new self-expanding device for closure of the patent foramen ovale (PFO). A transeptal catheter passage through the flap of the fossa ovalis was performed with a transeptal needle inside a catheter, creating a PFO in two minipigs. In an additional five animals, a naturally occurring PFO was found. The device is made from 0.005 inch nitinol wire mesh with polyester fabric inside, similar in construction to the Amplatzer atrial septal occluder. However, the left atrial disc is smaller (18 mm) than the right atrial disc (26 mm). Both discs are connected by a very short flexible waist (3 mm) that allows free movement of both retention discs. Pulmonary and right atrial angiography were performed after placement, at 1 month, and at 3 months follow-up. Placement of the device was technically successful in six animals. One animal died from ventricular fibrillation during placement. Pulmonary angiography and echocardiography showed complete occlusion of the PFO in six animals. Two animals were sacrificed after 1 month and four animals after 3 months. In the animals sacrificed at 1 month, histopathological examination showed partial (n = 2) endothelialization, and in the 3 months follow-up group (n = 4) endothelialization was complete. The device appears to be highly effective for occlusion of PFOs. This procedure may be performed as an outpatient procedure due to the small 7 Fr delivery system sheath. Cathet. Cardiovasc. Intervent. 47:370-376, 1999.

Alloys↗