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Biomedical subjects

X Gu

Publications and source records attributed to X Gu.

At least 127 records · Page 7Linked to original sources
PubMed1999

Epinephrine absorption after different routes of administration in an animal model.

BACKGROUND: The administration of epinephrine is the most important initial treatment in systemic anaphylaxis. PURPOSE: We wanted to determine the relationship between the route of epinephrine administration and the rate and extent of epinephrine absorption. METHODS: In a prospective, randomized, five-way crossover study in rabbits, we measured plasma epinephrine concentrations before, and at intervals up to 180 min after epinephrine administration by intramuscular or subcutaneous injection, or by inhalation, with intravenous epinephrine and intramuscular saline as the positive and negative controls, respectively. RESULTS: Maximum plasma epinephrine concentrations were higher, and occurred more rapidly, after intramuscular injection than after subcutaneous injection or inhalation, and were 7719+/-3943 (S.E.M.) pg/mL at 32.5+/-6.6 min, 2692+/-863 pg/mL at 111.7+/-30.8 min and 1196+/-369 pg/mL at 45. 8+/-19.2 min, respectively. Intravenous injection of epinephrine resulted in a plasma concentration of 3544+/-422 pg/mL at 5 min, and an elimination half-life (t(1/2)) of 11.0+/-2.5 min. In the saline control study, the endogenous epinephrine concentration peaked at 518+/-142 pg/mL. CONCLUSION: In this model, absorption of epinephrine was significantly faster after intramuscular injection than after subcutaneous injection or inhalation. The extent of absorption was satisfactory after both intramuscular and subcutaneous injections. Neither the rate nor the extent of absorption was satisfactory after administration by inhalation.

Absorption↗
PubMed1999

Diversity and evolution of T-cell receptor variable region genes in mammals and birds.

The receptor of a T lymphocyte (TCR) recognizes nonself antigens in the company of major histocompatibility complex (MHC) molecules presented to it by the antigen-presenting cell. The variable region of TCR is encoded by either a concatenation of variable region (TCR-V), diversity region (TCR-D), and joining region (TCR-J) genes, or a concatenation of TCR-V and TCR-J genes. The TCR-V genes exist as a multigene family in vertebrate species. Here we study the evolutionary relationships of TCR-V genes from humans, sheep, cattle, rabbits, mice, and chicken. These six species can be classified into two groups according to the frequency of gamma(delta) T-cells in their peripheral T-cell populations. The "gamma(delta) low" group of species includes humans and mice, in which gamma(delta)T-cells constitute very limited portion of the T-cell population. The "gamma(delta) high" group includes sheep, cattle, rabbits, and chicken, in which gamma(delta) T-cells comprise up to 60% of the T-cell population. Here, we compiled TCR-V sequences from the six species and conducted a phylogenetic analysis. We identified various TCR-V gene subgroups based on the analysis. We found that humans and mice have representatives from nearly all of the subgroups identified, while other species have lost subgroups to different extent. Therefore, the gamma(delta) low species have a high degree of diversity of TCR-V genes, while gamma(delta) high species all have limited diversity of TCR-V genes. This pattern is similar to that found for immunoglobulin variable region (IGV) genes.

Animals↗
PubMed1999

Perventricular [correction of Periventricular] closure of ventricular septal defects without cardiopulmonary bypass.

BACKGROUND: Minimally invasive techniques are currently in use to close atrial and ventricular septal defects (VSD). Cardiopulmonary bypass (CPB) is instituted via the femoral vessels, which may cause injury to these vessels, especially in younger patients. The objectives of this study were to demonstrate the feasibility of perventricular [corrected] closure of muscular VSD (MVSD) and paramembranous VSD (PVSD) without CPB, using the Amplatz VSD device. METHODS: Five Yucatan pigs with naturally occurring PVSD (3- to 7-mm diameter) and 5 dogs with surgically created MVSD (6- to 14-mm diameter) were subjects of this study. The VSDs were closed intraoperatively with a 7-French delivery sheath inserted through the free wall of the right (n = 5) or left ventricle (n = 5), under epicardial echocardiogram guidance. The animals were followed for 3 months. RESULTS: There was no operative mortality. All MVSD closed after placement of the device. Closure rate of PVSD was 4 of 5 after placement and 3 of 5 after 3 months. One pig developed aortic incompetence at the last follow-up. CONCLUSIONS: Perventricular closure of MVSD and PVSD is feasible. Avoidance of CPB can decrease recovery time, its complications, and trauma to the femoral vessels.

Animals↗
PubMed1999

Balance and physical impairments after stroke.

OBJECTIVE: To investigate the relationship among laboratory and clinical balance measures and physical impairments. DESIGN: A descriptive correlational study. SETTING: Research laboratory. PARTICIPANTS: Thirty subjects with stroke, recruited through convenience sampling. MAIN OUTCOME MEASURES: Postural sway was calculated in terms of center of pressure (COP) parameters including spectral characteristics. Clinical balance was measured using the Balance Scale. The assessed physical impairments included stages of lower limb motor recovery, ankle proprioception, and passive dorsiflexion range of the involved limb. RESULTS: The Balance Scale was correlated with COP speed (r = -.57), COP root mean square speed (r = -.50), and COP mean frequency (r = -.50) in the anterior-posterior direction only. Moderate to high correlations were found among most of the COP parameters except spectral characteristics. Significant differences in postural sway were found among different stance in eyes-open (p = .00 to .02) and eyes-closed conditions (p = .00 to .04). Subjects with impaired ankle proprioception had significantly increased postural sway and decreased Balance Scale scores when compared with the subjects with intact ankle proprioception. CONCLUSIONS: Some of the clinical and laboratory balance assessments were related, indicating that some components of the tests are similar, but some measured different aspects of balance. Postural sway was related to visual condition, stance position, and proprioception.

Activities of Daily Living↗
PubMed1999

The clinical pharmacology of brompheniramine in children.

BACKGROUND: Brompheniramine has been widely used in the treatment of allergic rhinitis and other disorders during the past 4 decades. There are no published studies of its clinical pharmacology in children. OBJECTIVES: This study was performed to test the hypothesis that brompheniramine would have a prompt onset of action and a 24-hour duration of action in children. METHODS: Before brompheniramine 4 mg was ingested, and at intervals from 0.5 to 30 hours thereafter, blood samples were obtained for quantitation of plasma brompheniramine concentrations by means of HPLC. Concurrently, epicutaneous tests with histamine phosphate were performed; wheals and flares were traced at 10 minutes, and the areas were measured by using a computerized digitizing system. RESULTS: In 14 children, mean age 9.5 +/- 0.4 years (SEM), the peak brompheniramine concentration was 7.7 +/- 0.7 ng/mL, and the time at which peak concentrations occurred was 3.2 +/- 0.3 hours. The terminal elimination half-life was 12.4 +/- 1.1 hours, and the oral clearance was 20.2 +/- 2.1 mL/min/kg. Compared with predose areas, the wheals and flares produced by histamine phosphate 1 mg/mL were significantly decreased from 0.5 to 30 hours and from 1 to 30 hours, respectively (P <.05), with mean maximum inhibition at 12 (52% +/- 9%) and 6 hours (72% +/- 10%), respectively. CONCLUSIONS: In children a single dose of brompheniramine produces prompt, long-lasting peripheral H1 -blockade. Revised dosage regimens may be needed in this population.

Adolescent↗
PubMed1999

The nitinol vascular occlusion plug: preliminary experimental evaluation in peripheral veins.

PURPOSE: To compare the nitinol occlusion plug with standard stainless steel coils for the occlusion of moderate-size peripheral veins. MATERIALS AND METHODS: The nitinol plug is a braided multilayered vascular occlusion device filled with thrombogenic polyester fibers. It is self-expanding and can be recaptured into its 6-F introducing sheath for repositioning prior to detachment. Ten occlusion procedures were performed in five dogs from a retrograde transjugular venous approach. Five nitinol plugs (diameter: 7.4 mm +/- 0.5) were deployed in five femoropopliteal veins (diameter: 6.5 mm +/- 0.7; mean oversizing 14.6%). Two sequential Gianturco coils (diameter: 7.4 mm +/- 0.9) were deployed in the corresponding contralateral veins (diameter: 6.2 mm +/- 0.8; mean oversizing 19.6%). Follow-up venography was performed at 1 month, following which the animals were killed and the vessels were explanted. RESULTS: Time-to-occlusion was significantly shorter with the nitinol plug as compared to two Gianturco coils (4.2 minutes +/- 3.4 vs 25.6 minutes +/- 14.1, respectively [P < .03]). At 1 month all but one coil-doublet (80%) had recanalized or migrated, compared to only one nitinol occluder (20%, P < .04). Histopathologic examination of plug-occluded veins showed a uniform organized matrix and underlying intimal proliferative response. CONCLUSION: A single nitinol occluder resulted in significantly faster occlusion time and significantly lower recanalization or migration rate than two Gianturco coils, in moderate-size peripheral veins.

Alloys↗
PubMed1999

Injury potential to venous valves from the Amplatz thrombectomy device.

PURPOSE: To evaluate the acute effects of the Amplatz thrombectomy device (ATD) on peripheral venous valves in a canine model. MATERIALS AND METHODS: ATD thrombectomy was performed in 17 veins, and control experiments with use of an 8-F sheath-dilator were performed in four veins. Prethrombectomy ascending venography was performed, followed by device passage across the vein segment. Post-thrombectomy ascending venography was then performed, followed by heparinization and euthanasia. The treated veins were carefully explanted and stored in formaldehyde for histopathologic examination. Severity of valve injury was graded on a scale of 0 to 4. RESULTS: In ATD-treated veins: 10 veins sustained no injury [grade 0] (diameter, 6.7 mm +/- 1.7; antegrade/retrograde approach, 5/5), five veins sustained mild injury [grade 1-2] (diameter, 5.2 mm +/- 0.8; antegrade/retrograde, 3/2), while the remaining two veins sustained moderate-to-severe injury [grade 3-4] (diameter, 5 and 6 mm; antegrade/retrograde, 1/1). In sheath-dilator treated veins: no injury [grade 0] in any of the four treated veins (mean diameter, 5.5 mm +/- 0.6; all retrograde). In ATD-treated veins, valve injury (of any grade) was significantly more frequent in veins 6 mm or less in diameter than in veins at least 7 mm in diameter (seven of 12 vs zero of five; P < .03). There was no significant association between thrombectomy approach and injury grade. CONCLUSION: Veins 7 mm or greater in diameter were associated with no significant valve injury during ATD thrombectomy. However, long-term and short-term effects on valvular function will need to be assessed.

Animals↗
PubMed1999

Capillary electrophoretic determination of resveratrol in wines.

A rapid and sensitive capillary electrophoretic method for analysis of resveratrol in wine was established. The protocol consists of sample preparation using a C-18 solid-phase extraction cartridge. Baseline separation of trans- and cis-resveratrol from other compounds in wine was achieved in approximately 8 min using a micellar mode. The limits of detection for trans- and cis-resveratrol were 0.1 and 0.15 micromol/L, respectively. Recovery rates for trans-resveratrol using the protocol described ranged from 94.6 +/- 8.5 to 101.9 +/- 7.2%. These procedures were used to analyze the trans- and cis-resveratrol levels in 26 wines. It was found that the concentration of trans-resveratrol ranged from 0.987 to 25.4 micromol/L, whereas the concentration of cis-resveratrol was much lower.

Antioxidants↗
PubMed1999

Three-dimensional structure of Selenocosmia huwena lectin-I (SHL-I) from the venom of the spider Selenocosmia huwena by 2D-NMR.

The three-dimensional structure of native SHL-I, a lectin from the venom of the Chinese bird spider Selenocosmia huwena, has been determined from two-dimensional 1H NMR spectroscopy recorded at 500 and 600 MHz. The best 10 structures have NOE violation <0.3 A, dihedral violation <2 deg, and average root-mean-square differences of 0.85 + 0.06 A over backbone atoms. The structure consists of a three-stranded antiparallel beta-sheet and three turns. The three disulfide bridges and three-stranded antiparallel beta-sheet form a inhibitor cystine knot motif which is adopted by several other small proteins, such as huwentoxin-I, omega-conotoxin, and gurmarin. The C-terminal fragment from Leu28 to Trp32 adopts two sets of conformations corresponding to the cis and trans conformations of Pro31. The structure of SHL-I also has high similarity with that of the N-terminus of hevein, a lectin from rubber-tree latex.

Amino Acid Sequence↗
PubMed1999

HLA-DR-DQ alleles and HLA-DP alleles are independently associated with susceptibility to different stages of post-schistosomal hepatic fibrosis in the Chinese population.

Abstract: Evaluation of human leukocyte antigen (HLA) class I and class II genes was performed on patients from China with Schistosomiasis japonica. Patients were categorized as grade 0 (n=44), grade I (n=81), grade II (n=99), or grade III (n=6) based on increasing severity of hepatic fibrosis due to repeated Schistosoma japonicum infections. These results show that the HLA-DRB1*1101-DQA1*0501-DQB1*0301 (Pc<0.02) and HLA-DRB1*1501-DRB5*0101 (Pc<0.02) haplotypes are associated with protection and susceptibility to grade I fibrosis, respectively, and that the HLA-DPA1*0103 -DPB1*0201 haplotype (Pc<0.02) is associated with protection from both grade II and III severe fibrosis. There was no association between HLA-B DNA haplotypes and the disease. These findings indicate that the HLA-class II molecules play a role in preventing or promoting fibrotic liver change after deposition with Schistosome eggs. Moreover, a tendency was observed within the HLA class II genes for the HLA-DR-DQ alleles to be associated with protection against early changes in liver fibrosis, whereas HLA-DP alleles were associated with protection from the late phase of fibrosis or severe hepatosplenic schistosomiasis.

Alleles↗
PubMed1999

Green and yellow vegetables can maintain body stores of vitamin A in Chinese children.

BACKGROUND: Vitamin A activity of plant provitamin A carotenoids is uncertain. OBJECTIVE: The objective was to determine whether plant carotenoids can sustain or improve vitamin A nutrition during the fall season in kindergarten children in the Shandong province of China. DESIGN: The serum vitamin A concentration of 39% of the children was <1.05 micromol/L and of 61% of the children was > or = 1.05 micromol/L. For 5 d/wk for 10 wk, 22 children were provided approximately 238 g green-yellow vegetables/d and 34 g light-colored vegetables/d. Nineteen children maintained their customary dietary intake, which included 56 g green-yellow vegetables/d and 224 g light-colored vegetables/d. Octadeuterated and tetradeuterated vitamin A were given before and after the interventions, respectively, and their enrichments in the plasma were determined by gas chromatography-mass spectrometry. Serum retinol and carotenoid concentrations were measured by HPLC. RESULTS: Carotenoid nutrition improved after consumption of green-yellow vegetables. Serum concentrations of retinol were sustained in the group fed green-yellow vegetables but decreased in the group fed light-colored vegetables (P < 0.01). The isotope-dilution tests confirmed that total-body vitamin A stores were sustained in the group fed green-yellow vegetables, but decreased 27 micromol (7700 microg retinol) per child, on average, in the group fed light-colored vegetables (P < 0.06). CONCLUSION: Green-yellow vegetables can provide adequate vitamin A nutrition in the diet of kindergarten children and protect them from becoming vitamin A deficient during seasons when the provitamin A food source is limited.

Analysis of Variance↗
PubMed1999

Statistical methods for testing functional divergence after gene duplication.

Functional innovations after gene duplication may result in altered functional constraints between member gene clusters of a gene family. This type (type I) of functional divergence is measured by the coefficient of functional divergence (theta lambda), which can be interpreted as the decrease in rate correlation between gene clusters, or the probability that the evolutionary rate at a site is statistically independent between two gene clusters. A simple stochastic model has been developed for estimating theta lambda and testing its statistical significance. The current model includes the model of rate variation among sites as a special case when theta lambda = 0. Moreover, we have developed a site-specific profile based on the hidden Markov model to identify critical amino acid residues that are responsible for these functional differences between two gene clusters, which may have great potential in functional genomics.

Gene Duplication↗
PubMed1999

Locus specificity of polymorphic alleles and evolution by a birth-and-death process in mammalian MHC genes.

We have conducted an extensive phylogenetic analysis of polymorphic alleles from human and mouse major histocompatibility complex (MHC) class I and class II genes. The phylogenetic tree obtained for 212 complete human class I allele sequences (HLA-A, -B, and -C) has shown that all alleles from the same locus form a single cluster, which is highly supported by bootstrap values, except for one HLA-B allele (HLA-B*7301). Mouse MHC class I loci did not show locus-specific clusters of polymorphic alleles. This was considered to be because of either interlocus genetic exchange or the confusing designation of loci in different haplotypes at the present time. The locus specificity of polymorphic alleles was also observed in human and mouse MHC class II loci. It was therefore concluded that interlocus recombination or gene conversion is not very important for generating MHC diversity, with a possible exception of mouse class I loci. According to the phylogenetic trees of complete coding sequences, we classified human MHC class I (HLA-A, -B, and -C) and class II (DRB1) alleles into three to five major allelic lineages (groups), which were monophyletic with high bootstrap values. Most of these allelic groups remained unchanged even in phylogenetic trees based on individual exons, though this does not exclude the possibility of intralocus recombination involving short DNA segments. These results, together with the previous observation that MHC loci are subject to frequent duplication and deletion, as well as to balancing selection, indicate that MHC evolution in mammals is in agreement with the birth-and-death model of evolution, rather than with the model of concerted evolution.

Alleles↗
PubMed1999

Bone marrow-derived dendritic cells incorporate and process hydrophobized polysaccharide/oncoprotein complex as antigen presenting cells.

We have previously shown that a novel hydrophobized polysaccharide/oncoprotein complex vaccine can induce immune responses against the HER2/neu/c-erbB2 (HER2) expressing tumors. Bone marrow-derived dendritic cells (DCs), as antigen presenting cells (APCs), are the first candidates for presentation of tumor antigens. The aim of this study was to see whether DCs are able to elicit antigen specific host immune responses by stimulating the proliferation of T cells after exposure to cholesteryl group bearing pullulan (CHP) and HER2 protein complex. Vaccination by CHP-HER2 complex was as effective as cholesteryl group bearing mannan (CHM) and HER2 complex on which we reported previously. Immunization of mice with HER2 expressing CMS17HE tumor cells generated both CD4+ T cells and CD8+ T cells reactive with CHP-HER2 complex pretreated DCs. In addition, immunization with either CHP-HER2 complex or HER2 protein alone could also generate both CD4+ T cells and CD8+ T cells specifically reactive with CHP-HER2 complex pretreated DCs. The complete rejection of tumors occurred when immunization with CHP-HER2 complex pretreated DCs was started 10 days after tumor inoculation. Therefore, bone marrow-derived DCs pretreated with hydrophobized polysaccharide/oncoprotein complex are a powerful tool for enhancing the effectiveness of oncoprotein for anti-tumor vaccination, opening new options for immune cell therapy.

Animals↗
PubMed1999

Expression of folate receptor alpha in the mammalian retinol pigmented epithelium and retina.

PURPOSE: Folic acid is essential for DNA, RNA, and protein synthesis, and deficiencies in folate can lead to nutritional amblyopia and optic neuropathy. The transport of folate from the choroidal blood supply to the retina is only now beginning to be understood. The reduced-folate transporter was reported recently to be present in cultured human retinal pigment epithelial (RPE) cells and is thought to be localized to the apical region of these cells. The authors hypothesize that the RPE plays a role in the vectorial transport of folate from the choroidal blood to the neural retina and uses not only the reduced-folate transporter but also the folate receptor alpha in mediating this transport. The purpose of the present study was to determine whether the folate receptor alpha was present in the RPE and, if so, whether it was distributed along the basolateral membrane of the RPE, supporting a role for the protein in the initial steps of folate transport into the RPE. METHODS: The expression of the folate receptor alpha in mouse RPE was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), functional assays, in situ hybridization, immunohistochemistry, and laser scanning confocal microscopy. RESULTS: RT-PCR analysis, cloning of the RT-PCR product, and subsequent sequencing established that folate receptor alpha mRNA transcripts are expressed in the mouse RPE/choroid and are expressed also in the neural retina. A heterologous functional expression assay using MTX(R)-ZR-75-1 cells showed that the folate receptor alpha cDNA obtained by RT-PCR from the RPE/choroid complex and the neural retina was functional as assessed by the binding of folic acid and by the uptake of N5-methyltetrahydrofolate. In situ hybridization localized the folate receptor alpha mRNA to the mouse RPE cells and to cells of the neural retina. The folate receptor alpha was detected immunohistochemically in the mouse and rat RPE and in several layers of the neural retina. Laser scanning confocal microscopy revealed the distribution of the folate receptor alpha along the basolateral region of the RPE and not the apical region. CONCLUSIONS: The present work represents the first analysis of the folate receptor alpha expression in intact mammalian retina. The receptor is present and functional in mouse RPE. It is distributed specifically along the basolateral surface of the RPE and is proposed to work in a coordinated manner with the reduced-folate transporter in the vectorial transport of folate from the choroidal blood to the neural retina.

Animals↗
PubMed1999

[Mutation in the promoter region of 21-hydroxylase gene of patients with congenital adrenal hyperplasia].

OBJECTIVE: To investigate the mutations in the 21-hydroxylase gene promoter region of patients with congenital adrenal hyperplasia (CAH). METHODS: The authors amplified a 1.6 kb fragment of the CYP21 gene which was confirmed by endonuclease digestion. The PCR product was re-amplified with promoter-region-specific primers. The amplified fragments were analyzed using SSCP and endonuclease digestion methods. RESULTS: Among 12 patients, 6 patients presented an abnormal band on SSCP analysis. By endonuclease digestion test, the authors found a patient who presented one mutation in KpnI recognition site located in the CK-2 (-101) binding region and one in Taq I recognition site located -201. These mutations were confirmed by sequencing. CONCLUSION: Novel mutations were found in the promoter of 21-hydroxylase gene in CAH patients and the findings spurred on further expression studies.

Adrenal Hyperplasia, Congenital↗
PubMed1999

[Effects of low-dose FP therapy for advanced gastric cancer cases].

The clinical application of low-dose FP therapy has spread rapidly in Japan. We examined the effects of this form of chemotherapy on patients with advanced gastric carcinoma in China. One cycle of this therapy consisted of intermittent infusion of CDDP (10 mg/body/3 hr), followed by intermittent infusion of 5-FU (250 mg/body/6 hr) and suppository administration of tegafur (500 mg) at night for 5 days with 2-day intervals. As a result, a partial response for the primary lesion and lymph nodes was obtained in some cases, 2 of which are described in this paper. No serious side effects were noted, although administration continued over a long period. Our results suggest that neoadjuvant chemotherapy with low-dose FP may be useful as an inductive approach for advanced gastric cancer, and that the regimen can become a standard therapy for gastric cancer.

Antineoplastic Combined Chemotherapy Protocols↗