Biomedical subjects

H Yang

Publications and source records attributed to H Yang.

At least 343 records · Page 19Linked to original sources

PubMed2000

Effects of dietary lysine intake during lactation on blood metabolites, hormones, and reproductive performance in primiparous sows.

Effects of three dietary lysine (protein) concentrations during lactation on metabolic state, protein metabolism, reproductive hormones, and performance were investigated in 36 primiparous sows. Sows were assigned randomly to one of three diets containing .4% (low lysine, LL), 1.0% (medium lysine, ML), or 1.6% (high lysine, HL) total lysine from intact protein sources. All diets contained 2.1 Mcal NE/kg and exceeded the recommended requirements for all other nutrients. Actual lysine intakes over an 18-d lactation were 16, 36, and 56 g/d for sows fed LL, ML, and HL, respectively. Fractional breakdown rate of muscle was determined on d 4 and 15 of lactation by using a three-compartment kinetic model of 3-methylhistidine metabolism. Increasing lysine intake during lactation did not affect fractional breakdown rate of muscle on d 4 of lactation but decreased it on d 15 (P < .05). Sows fed LL had a reduced number of LH pulses on d 12 and 18 (P < .05) and reduced serum estradiol (E2) concentration on d 18 of lactation compared with sows fed ML and HL treatments. However, LH pulses and E2 concentrations were similar between ML and HL treatments (P > .35). Increasing lysine intake increased serum urea nitrogen (SUN) and postprandial insulin concentrations (P < .05) during lactation but had no effect on plasma glucose concentrations (P > .20). Sows fed HL had greater serum IGF-I on d 6 and 18 than sows fed ML (P < .05). Number of LH peaks was correlated with serum insulin concentration 25 min after feeding on d 6 and 18 (r = .31 to .41; P < .1) and pre- (r = .33 to .46) and postprandial (r = .30 to .58) SUN concentrations (P < .05) during different stages of lactation. Results indicate that, compared with medium lysine intake, low lysine intake increased muscle protein degradation and decreased concentrations of insulin, SUN, and estradiol and LH pulsatility. In contrast, high lysine (protein) intake increased SUN, insulin, and IGF-I, but did not increase secretion of estradiol and LH compared with medium lysine intake. Furthermore, nutritional impacts on reproduction may be mediated in part through associated effects on circulating insulin concentration.

Animals↗

PubMed2000

Impact of dietary lysine intake during lactation on follicular development and oocyte maturation after weaning in primiparous sows.

Primiparous sows (n = 36) were used to evaluate the effects of dietary lysine intake in lactation on follicular development and oocyte maturation after weaning. Sows were assigned randomly to one of three diets containing .4% (low lysine, LL), 1.0% (medium lysine, ML), or 1.6% (high lysine, HL) total lysine. All diets contained 2.1 Mcal NE/kg and exceeded NRC (1988) requirements for all other nutrients. Actual lysine intakes over an 18-d lactation were 16, 36, and 56 g/d for sows consuming LL, ML, and HL, respectively. Ovarian data were analyzed for sows determined to have been slaughtered during the first proestrus period after weaning, using previously established criteria. Compared with sows fed ML and HL, sows fed LL tended to have lower uterine weight, follicular fluid volume, and follicular fluid (FF) estradiol (E2) content (P < .15), but similar ovarian weight and follicular fluid IGF-I concentration. Within the largest 15 preovulatory follicles, sows fed LL had a lower percentage of large (> or = 7.0 mm) follicles (33 vs 50 and 58%; P < .01) and a higher percentage of medium (5.5 to 7.0 mm) follicles (62 vs 44 and 39%; P < .01) but a similar percentage of small (< or = 5.5 mm) follicles (4.4 vs 5.9 and 3.7%; P > .15), respectively, compared with sows fed ML or HL. Standardized pools of oocytes aspirated from follicles of prepubertal gilts were incubated for 44 h with pooled FF recovered from the largest 15 follicles of each experimental sow. Fewer oocyte nuclei matured to metaphase II of meiosis when cultured with FF recovered from sows fed LL, than from sows fed ML or HL (47.1 vs 59.8 and 63.8%, respectively; P < .01). Our results suggest that low lysine (protein) intake in primiparous lactating sows impaired follicular development and reduced the ability of follicles to support oocyte maturation. However, high compared with medium lysine (protein) intake had no further positive effects on ovarian function.

Animal Nutritional Physiological Phenomena↗

PubMed2000

Complete genomic sequence of 195 Kb of human DNA containing the gene GABRG2.

GABA (gamma-aminobutyric acid), as the main inhibitory neurotransmitter in the brain, plays an essential role for the overall balance between neuronal excitation and inhibition by acting on GABAA receptors, which are ligand-gated chloride channels. Impaired GABAergic function contributes to certain forms of epilepsy, schizophrenia, Alzheimer's Disease, and other neurological disorders. In order to identify possible genetic features and to further study biological regulation of GABAA receptor genes whose promoter elements and sequence anomalies may contribute to epileptic disorders, as an initial step, we shot-gun sequenced a BAC clone, dj082c10 (195,909-bp in size), encompassing human gamma(2) subunit of GABAA receptor (GABRG2). It is, we believe, the first genomic sequence of the GABA receptor gamma subunit family. Four contigs were assembled from 2950 reads prior to gap in an average redundancy of eight folds over the entire region. The precision of the consensus sequence was predicted to be 99.999% after closing gaps and finishing weak regions. The nine exons of GABRG2 spans an 85-kb region that had 81 SINEs comprising 22.32%, and nine L1 elements comprising 3.40%, respectively. However, the density of L1 in the regions flanking GABRG2 gene (29.45% by 45 elements) is significantly higher than that within the gene. The length of GABRG2 introns varies in the range of 1.5 kb to 38.1 kb.

Amino Acid Sequence↗

PubMed2000

Vascularization of the human fetal retina: roles of vasculogenesis and angiogenesis.

PURPOSE: To characterize the topography of and the cellular processes that underlie vascularization of the human retina. METHODS: The vasculature of human eyes obtained from fetuses ranging in age from 14 to 38 weeks of gestation (WG) was examined in Nissl-stained, whole-mount preparations and by anti-CD34 immunohistochemistry. RESULTS: The first event in retinal vascularization, apparent before 15 WG, was the migration of large numbers of spindle-shaped mesenchymal precursor cells from the optic disc. These cells proliferated and differentiated to produce cords of endothelial cells. By 15 WG, some cords were already patent and formed an immature vascular tree in the inner retinal layers that was centered on the optic disc. These processes are consistent with vessel formation by vasculogenesis. Angiogenesis then increased the vascular density of this immature plexus and extended it peripherally and temporally. Maturation of the plexus was characterized by substantial remodeling, which involved the withdrawal of endothelial cells into neighboring vascular segments. The outer plexus was formed as a result of the extension of capillary-sized buds from the existing inner vessels, a process that began around the incipient fovea between 25 and 26 WG. CONCLUSIONS: These observations suggest that the formation of primordial vessels in the central retina is mediated by vasculogenesis, whereas angiogenesis is responsible for increasing vascular density and peripheral vascularization in the inner retina. In contrast, the outer plexus and the radial peripapillary capillaries are formed by angiogenesis only. These mechanisms of retinal vascularization appear similar to those of vascularization of the central nervous system during development.

Antigens, CD34↗

PubMed2000

Anatomic evaluation of the first three sacral vertebrae and dorsal screw placement.

Although the anthropometric studies of the first sacral vertebra have been previously described, there are few studies that define and compare the morphological features of the S-1 to S-3 vertebrae. Twenty sacra were directly measured, and then digitized images of macroscopic cross-sectional specimens were measured by using Color Image 1.31 software. Measurements, including parameters from sacral vertebral bodies, sacral canal, and auricular articular surfaces of the first three sacral vertebrae, were obtained. The contributions by the first, second, and third sacral vertebrae to the auricular articular surface area were 50%, 35%, and 15%, respectively. The parameters related to the S-1 and S-2 medial and lateral screw placement were also determined. All measured parameters of the upper three sacral vertebral bodies and the sacral canal gradually decreased from S-1 to S-3. This study provides morphometric data of the first three sacral vertebrae that may prove helpful for better understanding the unique anatomy of the sacrum and transpedicular and lateral mass screw placement.

Aged↗

PubMed2000

[Investigation of infiltration glass of the machinable infiltrated ceramic(MIC)].

To explore the manufacture arts and determine the properties of the infiltration glass of the MIC. In order to determine the glass forming range of the MIC infiltration glass, molten glass was prepared in Al2O3 crucibles by heating the components to 1450 degrees C. Thermal analytic device was employed to study the thermal properties of the glass. Its crystal phases after micro-crystallization were analyzed with XRD. Flexural strength was measured by means of 3-point bending test. The chemical components of MIC glass were determined. Conventional fluorophlogopite glass was converted into an infiltration glass with low viscosity, good infiltration capability and low fusing temperature by introducing B2O3, La2O3 and Li2O into the glass. Fluorophlogopite crystals formed after crystallization. Conventional mica glass can be changed according to the requirements of properties. Modified mica MIC glass in this study has good infiltration ability in Al2O3 matrix while remains machinability.

Aluminum Silicates↗

PubMed2000

Prediction of renal transplant survival from early postoperative radioisotope studies.

UNLABELLED: It has been routine at the University of Alabama Medical Center to obtain a radionuclide renal function study immediately after transplantation (usually within 3 d) that includes estimation of effective renal plasma flow (ERPF) from a single plasma sample in addition to imaging. We present here the correlation between baseline measurements and the 1-y graft survival. METHODS: Two cohort years were reviewed: 1988, when 131I-orthoiodohippurate (OIH) was used; and 1995, when 99mTc-mercaptoacetyltriglycine (MAG3) was used. ERPF was measured concurrently with gamma-camera imaging by previously published single-injection, single-sample methods (converting MAG3 clearance to ERPF by means of a correction factor). RESULTS: Graft survival during the first postoperative year improved significantly in the interval between cohort years, from 74% of 147 cadaver (CD) grafts in 1988 to 91% of 200 CD grafts in 1995 (log rank test, P < 0.05). In contrast, for living related donor (LRD) grafts there was no significant change, from 91% of 66 in 1988 to 91% of 83 in 1995. The baseline ERPF was a significant predictor of graft survival in both 1988 and 1995 (Wilcoxon test, P > 0.05). For LRD grafts the association was not significant in either year. Using MAG3 (1995), the peak time and the ratio of counting rate (R) at 20 min to that at 3 min (R20:3) were also significant predictors for CD graft survival. Using OIH (1988 cohort), the correlation with peak time did not reach significance, and the R20:3 measurement was not available. Although multivariate combinations (Cox proportional hazards model) did not have significantly more predictive value at the 95% confidence level than ERPF or R20:3 alone, some statisticians suggest a 75% confidence level for adding an additional covariate to a multivariate model. Use of this level led to a model including both ERPF and R20:3. CONCLUSION: Single-sample ERPF measured in the immediate post-transplant period, whether from OIH clearance or MAG3 clearance, was a statistical predictor of graft survival for CD transplants. For MAG3, the peak time and R20:3 were also significant predictors. These associations held only for CD transplants and not for LRD transplants.

Cohort Studies↗

PubMed2000

Signal transduction and biochemical targeting of ovarian carcinoma.

UNLABELLED: The purpose was to identify novel targets for the chemotherapy of ovarian carcinoma. METHODS: Assays were worked out to measure the activities of P1 kinase, PIP kinase and PLC in ovarian carcinoma samples and in OVCAR-5 cells and to compare the activities to those in normal ovaries. A method was also designed for measuring the concentration of the end product of signal transduction, IP3. RESULTS AND DISCUSSION: Signal transduction activity was markedly increased in ovarian cancer cells as shown by the increased steady-state activities of the three enzymes and the elevated concentrations of IP3. Inhibitors blocked activities of PI kinase (quercetin), PIP kinase (genistein), and lowered GTP concentration required for PLC (tiazofurin). Combinations of tiazofurin with quercetin, tiazofurin with genistein, and quercetin with genistein yielded a synergistic kill of ovarian cancer cells. Tiazofurin, quercetin and genistein are in various stages of clinical trials. CONCLUSION: The increased signal transduction activity provides novel, sensitive targets to chemotherapy in ovarian cancer cells.

Cell Survival↗

PubMed2000

[Reactivation of denatured lysozyme with immobilized molecular chaperones GroE].

The molecular chaperones GroEL and GroES were expressed in recombinant E. coli and purified by anion exchange chromatography. The renaturation of the denatured lysozyme with the free and immobilized GroEL/ES or GroEL was studied. We show here that using free GroEL alone could reactive the denatured lysozyme up to a relative activity of over 90%. The immobilized GroEL was also effective for promoting lysozyme refolding. Moreover, the optimal temperature (i.e., 37 degrees C) and (pH(i.e., 6 to 8) for the immobilizde GroEL-facilitated lysozyme refolding operation were determined. Under the optimal condition, the activity of lysozyme could be recovered up to 85%. In addition, the immobilized GroEL was repeatedly used five times without loss of its renaturation ability, indicating its potentiality to be used in practical downstream bioprocesses.

Chaperonin 10↗

PubMed2000

Actions of NO and INOS on endotoxin induced rat acute lung injury and effect of rhubarb on them.

This study is to explore the actions of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) on endotoxin (lipopolysaccharide, LPS) induced rat acute lung injury (ALI) and effect of Rhubarb on them. LPS was injected into the sublingual vein of male Wistar rats to prepare ALI animal models. The rats were divided into 4 groups: LPS, control, Rhubarb, and dexamethasone. Macroscopic and histopathological examinations of the lung specimens were performed and the biological indexes of lung, including wet weight/dry weight, the rate of neutrophils and protein content in the pulmonary alveolar lavage fluid, pulmonary vascular permeability and pulmonary alveolar permeability were observed. In the mean time, the contents of serum NO and the activities of lung tissue homogenate iNOS were measured. The results showed that in the LPS group, the injury and celluar infiltration in the pulmonary stroma and alveoli were more prominent than that in the control group. Lung wet weight/dry weight, the rate of neutrophils, protein content, pulmonary alveolar permeability, pulmonary vascular permeability were significantly increased (P < 0.01); NO and iNOS were also markedly elevated (P < 0.01). In the groups of dexamethasone and Rhubarb, the histopathological changes were significantly milder, and all the above biological indexes of lung injury and the contents of NO and the activities of iNOS were correspondingly decreased (P < 0.05). The above data demonstrate that NO and iNOS play an important role in the onset of ALI; dexamethasone and Rhubarb interfering treatment can ameliorate lung injury and decrease the concentrations of NO and the activities of iNOS, showing that through inhibiting the levels of NO and the activities of iNOS, these 2 agents exert protective effect on ALI induced LPS.

Animals↗

PubMed2000

Location of the first and second sacral nerve roots in relation to pedicle screw placement.

Dissection and measurements of the first 2 sacral nerve roots with regard to the commonly used entrance points for S1 and S2 pedicle screw placement were performed to determine the location of the first 2 sacral nerve roots in relation to the pedicle screw entrance points in the upper 2 sacral vertebrae. The sacral nerve roots, dural sac, and pedicles were exposed after laminectomy. The mean distance from the reference point to the adjacent nerve roots superiorly and inferiorly at the S2 pedicle level was smaller than those at the S1 pedicle level. The medial angle of the sacral nerve roots progressively decreased from L5 to S3. The nerve root passing through the next foramen formed an immediate medial relation to the sacral pedicle rather than the dural sac. Pedicle screw placement in the first 2 sacral vertebral pedicles has been recommended for lumbosacral fusion and internal fixation of sacral fractures. No anatomic study is available regarding the location of the sacral nerve roots relative to the entrance points of sacral pedicle screw placement. Violation of the sacral canal and foramina by a sacral pedicle screw may injure the sacral nerve roots, especially at the level of the S2 pedicle.

Bone Screws↗

PubMed2000

Analysis of DYS19 and DYS287 polymorphisms in the Han population and three other ethnic groups of northeast China.

The allelic distribution of the Y-chromosome specific microsatellite DYS19 in the Han population and in the Daur, Oroqen and Ewenki ethnic groups (Northeast China) was analyzed by PCR and denatured polyacrylamide gel electrophoresis. The allelic distribution in the Han population group is as follows: A = 2.90%, B = 26.09%, C = 26.09%, D = 29.98%, E = 15.94%. This allelic distribution differs statistically significant from that observed in the three other ethnic groups (p < 0.05). Furthermore the polymorphism of the Y-chromosome specific Alu insert sequence DYS287 was tested in these four groups. However, no Alu sequence insert was found.

Alleles↗

PubMed2000

Analysis of polymorphic mitochondrial DNA in the Han population and three other ethnic groups of northeast China.

By means of the PCR-RFLP technique the polymorphism of a 465 fragment of mtDNA D loop was analyzed in 36 individuals of the Northeast Han, 30 individuals of the Daur, 32 individuals of the Oroqen and 30 individuals of the Ewenki. All these individuals were randomly selected and are healthy. 27 restriction patterns were obtained by assaying the RFLP fragments of the mtDNA D loop. The mean nucleid acid substitute frequencies at each site are the following: Northeast Han = 0.0291, Oroqen = 0.0477, Ewenki = 0.0563, Daur = 0.0541. The genetic relationship between these four populations was analyzed by the UPG cluster analysis.

Asian People↗

PubMed2000

Humalog Mix25 offers better mealtime glycemic control in patients with type 1 or type 2 diabetes.

To compare the postprandial glucodynamics of Humalog Mix25, (Humalog Mix75/25 in the US; Mix25), to human insulin 30/70 (Humulin 70/30 in the US; 30/70) in patients with type 1 or type 2 diabetes. Ninety-three patients with type 1 diabetes and 84 patients with type 2 diabetes were evaluated in two separate but identical protocols using a randomized, multicenter, double-blind, crossover design. Patients consumed test meals 5 minutes after equal doses of Mix25 or 30/70. Plasma glucose was measured at baseline and 15 minute intervals for 4 hours after the meal. Two-hour postprandial glucose (2pp), 2-hour glucose excursion (2pp(ex) ), glucose versus time area under the curve 0 to 4 hours (AUC(0-4) ) and glucose excursion area under the curve 0 to 2 and 0 to 4 hours (AUCex(0-2), AUCex(0-4) ) were calculated. For the combined patient population, Mix25 resulted in significantly lower 2pp (12.45 +/- 3.59 vs. 13.47 +/- 3.62 mmol/L; p <0.001), AUC(0-4) (44.45 +/- 12.20 vs. 47.25 +/- 11.97 mmol x h/L; p <0.001), and glucose excursion parameters: 2pp(ex) (3.20 +/- 2.72 vs. 4.40 +/- 2.81 mmol/L; p <0.001), AUCex(0-2) (5.45 +/- 3.15 vs 6.60 +/- 3.13 mmol x h/L; p <0.001), and AUCex(0-4) (7.57 +/- 8.37 vs. 11.02 +/- 8.47 mmol x h/L; p <0.001) compared to 30/70. Further analysis of the treatment by type of diabetes indicated that Mix25 provided nearly identical glucose excursion responses in type 1 and type 2 diabetes up to 2 hours after the test meal, in contrast to 30/70. Pre-meal injection of Mix25 resulted in lower postprandial blood glucose levels compared to 30/70. The postprandial blood glucose response following Mix25 was similar in patients with either type 1 or type 2 diabetes.

Adult↗

PubMed2000

[Expression of bcl-2 gene in relation to histologic type and grade, and prognosis of breast cancer].

OBJECTIVE: To ascertain whether bcl-2 gene expression is related to histologic type and grade, and prognosis of breast cancer and its prognosis. METHODS: Expression of bcl-2 protein was examined immunohistochemically in 85 cases of breast cancer patients with > or = 5 years of follow-up. RESULTS: Expression of bcl-2 protein was detectable in 68.2% of breast cancer specimens. It was not related to histologic type, but to histologic grade of the cancer. In grade I, bcl-2 was positive in 95.2% of the specimens which was significantly higher than that in grade II (64.6%) and grade III (25.0%)(P < 0.01). The positive rate of bcl-2 expression was 75.9% in patients who survived > or = 5 years as compared to that (51.6%) in patients survived < 5 years (P < 0.05). CONCLUSION: Expression of bcl-2 occurs more frequently in well differentiated breast cancer. It is associated with better prognosis of the patients.

Adult↗

PubMed2000

Clinical observation on the long-term therapeutic effects of traditional Chinese medicine for treatment of liver fibrosis.

48 patients with liver fibrosis due to hepatitis B were treated for 2 years with the drugs for tonifying the kidney, supplementing qi, cooling and invigorating the blood and detoxification. The symptoms were markedly improved, and serum ALT and bilirubin were recovered and kept normal in most of the cases. The mean levels of serum hyaluronic acid, procollagen peptide III and circulating immune complex were decreased and returned to normal after the treatment. B-ultrasonography showed that the portal vein kept in normal size in 82% of the patients, the enlarged portal vein diminished in diameter, and the enlarged spleen reduced.

Adult↗

PubMed2000

Effect of anti-digoxin antiserum on endoxin and membrane ATPase activity in hypoxia-reoxygenation induced myocardial injury.

AIM: To evaluate the protective effect of anti-digoxin antiserum on hypoxia-reoxygenation induced injured myocardium and its mechanism. METHODS: Anti-digoxin antiserum of different concentrations was used, its effect on endoxin and ATPase activity in cell membrane in hypoxia-reoxygenation myocardium model was observed. RESULTS: The level of endoxin was remarkably higher, ATPase activities in cell membrane were remarkably lower in hypoxic group and hypoxia-reoxygenation injury group than those of normal group; anti-digoxin antiserum could resume ATPase activity in a concentration-dependent manner. CONCLUSION: Rise of endoxin was the molecular biological basis of myocardial damage during myocardial hypoxia-reoxygenation. Anti-digoxin antiserum had lessened myocardial injury and had a protective effect on hypoxia-reoxygenation myocardium by antagonizing effect of endoxin.

Animals↗

PubMed2000

[The effect of ginkgo biloba on hypoxic pulmonary hypertension and the role of protein kinase C].

OBJECTIVE: To elucidate whether the mechanism of relieving hypoxic hypertension by ginkgo biloba involves attenuation of the function of protein kinase C(PKC) signal channel. METHODS: 1. Wistar rats were randomly divided into control(C), hypoxic(H) and ginkgo biloba treatment(GB + H) (200 mg.kg-1.d-1, orally) groups (n = 7). Each rat was first measured mean pulmonary arterial pressure (mPAP), mean systemic arterial pressure (mSAP) and the ratio of the weight of right ventricle to that of left ventricle plus septum [RV/(LV + S)], than two main pulmonary artery rings were isolated to exposed to PDBu(a specific activator of PKC) to observe the time-response curve and the dose-response curve in response to 500 nmol/L PDBu and 10-11,000 nmol/L PDBu respectively to evaluate the function of protein kinase C signal channel. 2. Intrapulmonary artery rings of human(IARH) from pneumolobectomy were randomly divided into PDBu, RO318220 (inhibitor of PKC) + PDBu and ginkgolide B(BN52021) + PDBu groups(n = 6), the IARH of three groups were exposed to 1-25 nmol/L PDBu to achieve dose-response curves respectively. RESULTS: (1) mPAP, RV/(LV + S) of the H group were greater than those of C and GB + H groups respectively (P < 0.05). mPAP of GB + H group was greater than that of C group (P < 0.05). In PA experiments, the function of protein kinase C of H group was higher than those of C and GB + H groups respectively(P < 0.05). (2) In IARH experiments, the function of protein kinase C of PDBu group was higher than those of RO318220 + PDBu and BN52021 + PDBu groups respectively(P < 0.05). CONCLUSIONS: Ginkgo biloba can reduce chronic hypoxic pulmonary hypertension and relieve the hypertrophy of right ventricle, which is partly related to attenuation of the function of PKC signal channel.

Animals↗