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Biomedical subjects

H Zhu

Publications and source records attributed to H Zhu.

At least 271 records · Page 15Linked to original sources
PubMed1999

Glycyl-glutamine-enriched long-term total parenteral nutrition attenuates bacterial translocation following small bowel transplantation in the pig.

BACKGROUND: Improvements in immunosuppression, operative procedure, and posttransplant management have made clinical small bowel transplantation (SBT) feasible. Ischemia and reperfusion injury, total parenteral nutrition (TPN), and devoidment of enteral feeding lead to graft atrophy, gut barrier dysfunction, and bacterial translocation. Glutamine (Gln) is the principal fuel for the enterocyte. The influence of Gln dipeptide-supplemented TPN, especially long-term TPN, on intestinal graft permeability and bacterial translocation is not clear following SBT in the large animal model. Therefore, we studied the effect of glutamine dipeptide, glycyl-glutamine (Gly-Gln), on bacterial translocation following SBT in the pig, which has a physiology similar to humans. MATERIALS AND METHODS: The outbred pigs underwent segmental small bowel autotransplantation and were divided into two groups. In the STPN group (n = 5), the animal received standard TPN devoid of Gly-Gln for 28 days. In the GTPN group (n = 5), the animal received isonitrogenous (0.3 g/kg.day) and isocaloric (33 kcal/kg.day) TPN solution with 2% Gly-Gln for 28 days. RESULTS: At the end of the experiment, Gly-Gln-enriched TPN could maintain the plasma Gln level, graft mucosal Gln and protein concentrations, and skeletal muscle Gln and protein concentrations. Gly-Gln-enriched TPN significantly decreased the bacterial number of mesenteric lymph nodes in the liver and spleen and intestinal permeability to 99mTc-DTPA. There were no significant differences in body weight gain. CONCLUSIONS: The Gly-Gln-enriched long-term TPN may maintain the plasma Gln level, mucosal and muscle Gln, and protein concentrations and attenuate the intestinal permeability to 99mTc-DTPA and bacterial translocation following small bowel transplantation in the pig.

Animals↗
PubMed1999

Clinical effects and mechanism of chanlibao in accelerating second stage of labor.

To observe the clinical effects and the mechanism of Chanlibao (CLB, a preparation of Chinese herbal medicine) in accelerating second stage of labor, primiparae were divided into 3 groups at random. CLB or oxytocin (OTC) was given to the CLB group (n = 80) and the OTC group (n = 52) respectively. The third group served as controls (n = 29). The control group consisted of women experiencing natural labor and to whom no drug was given. The time of second stage of labor and prognosis of mother and newborn of different groups were observed and compared. And intrauterine pressure and fetal heart rate were monitored by means of electronic monitoring. Isolated uterine muscular tissue was used to observe the reactivity to CLB. The results showed that the time of second stage of labor and postpartum hemorrhage in the CLB group were less than those in the control group and the average intrauterine pressure in the former was higher than that in latter, so was the contraction strength of isolated uterine muscle, but with no difference as compared with the OTC group. No side effect of CLB was found. It is concluded that CLB could obviously strengthen uterine contraction and accelerate second stage of labor. Moreover, it is inexpensive, convenient and free of side effect. It can be used as a new, safe and effective alternative for improving prognosis of mother and newborn, especially those not indicated for oxytocin or profuse infusion.

Adult↗
PubMed1999

Preparation and characterization for bispecific antibodies of anti-CD3 x anti-idiotype to B cell lymphocytic leukemia.

Bispecific antibodies (BsAbs) of anti-CD3 x anti-idiotype (Id) to B-cell lymphocytic leukemia (CLL) were prepared by chemical conjugation and direct hybridization technique of hybridoma and hybridoma without screening markers. The specificity of BsAbs from culture supernatants or ascites was assayed by indirect ELISA and indirect immunoflourescence (IF). The results showed that BsAbs could specifically react with homologous serum IgM from patients with B-CLL and cells carrying CD3 marker respectively. Cell combination test and LDH assay demonstrated that BsAb significantly increased the conjugate formation between lymphocyte activated kill (LAK) cells and Daudi cells, and enhanced the cytotoxic activity of LAK cells against Daudi cells.

Antibodies, Anti-Idiotypic↗
PubMed1999

Anti-proliferative effects induced by anti-CD4 human/murine chimeric antibody and murine anti-CD4 monoclonal antibody.

The effects of chimeric anti-CD4 human/murine chimeric antibody and murine anti-CD4 monoclonal antibody (McAb) on the proliferation induced by anti-CD3 McAb, phytohemagglutinin (PHA), IL-2, and allogeneic cells were studied. The results showed that chimeric anti-CD4 antibody and murine anti-CD4 McAb could inhibit the proliferation induced by the above inducers and the inhibitory effects were related to the dosage of the antibodies.

Animals↗
PubMed1999

Flow requirements in ventricular fibrillation: An in vivo nuclear magnetic resonance analysis of the left ventricular high-energy phosphate pool.

STUDY OBJECTIVE: We sought to determine whether flow rates of approximately 60% of normal values are sufficient to preserve the left ventricular myocardial high-energy phosphate pool during ventricular fibrillation (VF). METHODS: Mixed-breed swine (weight 22. 4+/-2.5 kg) were anesthetized with alpha-chloralose, placed in a state of VF, and perfused with extracorporeal circulation at a target flow of 50 mL.kg(-1).min(-1). In vivo whole-wall (average of left ventricular wall) and spatially localized phosphorous-31 nuclear magnetic resonance (NMR) spectra were acquired at baseline and during VF. RESULTS: Mean flow during VF was 58+/-20 mL.kg(-1). min(-1) (+/-SD; 95% confidence interval, 44 to 71) or about 60% of baseline cardiac output (n=13). Whole-wall adenosine triphosphate (ATP) decreased during perfused VF (P <.05), whereas creatine phosphate (CP) remained unchanged from baseline. With spatially localized NMR, the ratios of CP/ATP were similar at baseline in all layers (endocardium --> epicardium) of the left ventricular wall. However, during perfused VF, subepicardial CP/ATP ratios increased by 14% to 40% compared with baseline values, whereas subendocardial CP/ATP ratios remained unchanged (1% to 3% increase). An additional 4 animals perfused at 72+/-10 mL.kg(-1).min(-1) (+/-SD; 95% confidence interval, 56 to 92) during VF had preservation of CP and ATP levels. CONCLUSION: Flow levels equivalent to 60% of baseline cardiac output were insufficient to maintain normal high-energy phosphate levels in the in vivo fibrillating myocardium. At this level of flow, myocardial high-energy phosphate loss is nonhomogeneous within the left ventricular wall.

Adenosine Triphosphate↗
PubMed1999

Cognitive, cardiac, and physiological safety studies in ultra high field magnetic resonance imaging.

A systematic analysis of the effect of an 8.0 tesla static magnetic field on physiological and/or cognitive function is presented in the normal volunteer and in the swine. A study of ten human subjects revealed no evidence of detectable changes in body temperature, heart rate, respiratory rate, systolic pressure, and diastolic blood pressure after 1 hour of exposure. In addition, no cognitive changes were detected. Important ECG changes were noted which were related both to the position of the subject in the magnet and to the absolute strength of the magnetic field. As such, the ECG tracing at 8 tesla was not diagnostically useful. Nonetheless, all subjects exhibited normal ECG readings both before and following exposure to the 8 tesla field. Cardiac function was also examined in detail in the swine. No significant changes in body temperature, heart rate, left ventricular pressure, left ventricular end diastollic pressure, time rate of change of left ventricular pressure, myocardial stiffness index, cardiac output, systolic volume, troponin, and potassium levels could be detected following 3 h of exposure to a field strength of 8.0 tesla. It is concluded that no short term cardiac or cognitive effects are observed following significant exposure to a magnetic field of up to 8.0 tesla.

Animals↗
PubMed1999

Entrapment of Rhodobacter sphaeroides RV in cationic polymer/agar gels for hydrogen production in the presence of NH4+.

Cationic polyelectrolytes (chitosan, poly-L-lysine (PLL), polyethyleneimine (PEI) and trimethylammonium glycol chitosan iodide (TGCI)) were used to entrap anoxygenic phototrophic bacteria in order to prevent the inhibitory effect of NH4+ on hydrogen production. When combined with agar gel, chitosan and PLL demonstrated no obvious repressive effect on hydrogen production by Rhodobacter sphaeroides under light-anaerobic conditions with lactate and glutamate as the carbon and nitrogen sources, respectively. On the other hand, both PEI and TGCI exerted a detrimental effect on hydrogen production under these conditions. Hydrogen production in the presence of NH4+ by the bacteria entrapped in the complex gel containing chitosan and agar improved considerably compared to that in the control containing only agar. Evidence shows that chitosan improves the hydrogen production via various effects. Diffusion tests demonstrated that the addition of chitosan increased to some extent the resistance to the diffusion of positively charged NH4+, but had no effect on negatively charged lactate. A buffer effect in the complex gels was also revealed.

Journal Article↗
PubMed1999

Effect of divergent selection for total plasma phosphorus on plasma and yolk very low density lipoproteins and plasma concentrations of selected hormones in laying Japanese quail.

Japanese quail lines were divergently selected over 32 generations for laying hen plasma yolk precursor, as measured by total plasma phosphorus (TPP). The high (HP) and low (LP) lines were developed from a randombred control population (R1) that was maintained without conscious selection. The purpose of the present study was to characterize the composition of very low density lipoproteins (VLDL) in laying Japanese quail hens (VLDLy) and the concentration of selected hormones in laying hens from the HP, LP, and R1 lines. The changes in TPP because of genetic selection in the Japanese quail lines were associated with large alterations in plasma VLDLy concentration (HP > R1 > LP), but only minor changes in lipid composition and size (HP > LP = R1; P< or =0.01) of plasma VLDLy particles. Basal plasma levels of hormones associated with reproduction and lipid metabolism were also different among lines, with luteinizing hormone (LH) ranking HP >R1 = LP and triiodothyronine (T3), thyroxine (T4), and 17beta-estradiol ranking HP > R1 > LP (P< or =0.05). The results suggest possible increased rates of hepatic lipogenesis, hepatic VLDLy assembly and secretion, and plasma VLDLy concentration in association with increases in concentrations of plasma LH, T3, T4, and 17beta-estradiol. Concentrations of total lipids in yolk VLDL were not different among lines, and only minor line differences in the concentration of different classes of yolk VLDL neutral lipids were detected. The data indicate a preferential uptake of a specific plasma VLDLy subpopulation into rapidly growing ovarian follicles, resulting in a constant composition of yolk VLDL of laid eggs among lines of Japanese quail with large differences in plasma VLDLy concentration.

Animals↗
PubMed1999

Sequence specificity, statistical potentials, and three-dimensional structure prediction with self-correcting distance geometry calculations of beta-sheet formation in proteins.

A statistical analysis of a representative data set of 169 known protein structures was used to analyze the specificity of residue interactions between spatial neighboring strands in beta-sheets. Pairwise potentials were derived from the frequency of residue pairs in nearest contact, second nearest and third nearest contacts across neighboring beta-strands compared to the expected frequency of residue pairs in a random model. A pseudo-energy function based on these statistical pairwise potentials recognized native beta-sheets among possible alternative pairings. The native pairing was found within the three lowest energies in 73% of the cases in the training data set and in 63% of beta-sheets in a test data set of 67 proteins, which were not part of the training set. The energy function was also used to detect tripeptides, which occur frequently in beta-sheets of native proteins. The majority of native partners of tripeptides were distributed in a low energy range. Self-correcting distance geometry (SECODG) calculations using distance constraints sets derived from possible low energy pairing of beta-strands uniquely identified the native pairing of the beta-sheet in pancreatic trypsin inhibitor (BPTI). These results will be useful for predicting the structure of proteins from their amino acid sequence as well as for the design of proteins containing beta-sheets.

Amino Acids↗
PubMed1999

In-vivo myocardial substrate alteration during perfused ventricular fibrillation.

OBJECTIVES: Earlier work suggests the in-vivo heart alters its substrate utilization as a function of cardiac work. Previous work has also demonstrated the high oxygen requirements of the heart during ventricular fibrillation (VF). The authors hypothesized that myocardial substrate utilization during VF with perfusion is similar to the normal beating heart under conditions of increased workload. METHODS: Myocardial substrate selection was studied in the in-vivo porcine myocardium using 13carbon nuclear magnetic resonance (13C NMR) under conditions of increased cardiac work (dobutamine group) and VF with extracorporeal perfusion (VF group). Once the animal preparation was completed, metabolic steady state was achieved with the infusion of unlabeled acetate into the left anterior descending (LAD) coronary artery. The infused substrate was then changed to [2-13C] acetate and glutamate pool labeling was monitored by 13C NMR. The glutamate C4 resonance areas at baseline and after intervention of either increased workload (dobutamine group) or perfused VF (VF group) were compared within groups using paired t-tests. RESULTS: Baseline aortic and great cardiac vein lactates, glucose levels, blood gases, hemoglobin levels, and temperatures were similar between groups. In both groups, there was a significant decrease from baseline in the labeling of C4 glutamate peaks (dobutamine group: 20.2+/-14.9 vs 84.7+/-32.7, p = 0.002; and VF group: 49.8+/-24.4 vs 83.9+/-24.4, p = 0.02), indicating selection against acetate oxidation in favor of other endogenous substrates. CONCLUSIONS: In the in-vivo heart, despite the absence of functional contractions, changes in substrate utilization during perfused VF are similar to changes that occur with increased workload in the normal beating heart.

Acetates↗
PubMed1999

IkappaB kinase (IKK)-associated protein 1, a common component of the heterogeneous IKK complex.

Activation of the transcription factor NF-kappaB is controlled by the sequential phosphorylation, ubiquitination, and degradation of its inhibitory subunit, IkappaB. We recently purified a large multiprotein complex, the IkappaB kinase (IKK) signalsome, which contains two regulated IkappaB kinases, IKK1 and IKK2, that can each phosphorylate IkappaBalpha and IkappaBbeta. The IKK signalsome contains several additional proteins presumably required for the regulation of the NFkappaB signal transduction cascade in vivo. In this report, we demonstrate reconstitution of IkappaB kinase activity in vitro by using purified recombinant IKK1 and IKK2. Recombinant IKK1 or IKK2 forms homo- or heterodimers, suggesting the possibility that similar IKK complexes exist in vivo. Indeed, in HeLa cells we identified two distinct IKK complexes, one containing IKK1-IKK2 heterodimers and the other containing IKK2 homodimers, which display differing levels of activation following tumor necrosis factor alpha stimulation. To better elucidate the nature of the IKK signalsome, we set out to identify IKK-associated proteins. To this end, we purified and cloned a novel component common to both complexes, named IKK-associated protein 1 (IKKAP1). In vitro, IKKAP1 associated specifically with IKK2 but not IKK1. Functional analyses revealed that binding to IKK2 requires sequences contained within the N-terminal domain of IKKAP1. Mutant versions of IKKAP1, which either lack the N-terminal IKK2-binding domain or contain only the IKK2-binding domain, disrupt the NF-kappaB signal transduction pathway. IKKAP1 therefore appears to mediate an essential step of the NF-kappaB signal transduction cascade. Heterogeneity of IKK complexes in vivo may provide a mechanism for differential regulation of NF-kappaB activation.

Amino Acid Sequence↗
PubMed1999

Association between the C825T polymorphism of the G protein beta3-subunit gene and hypertension in blacks.

A polymorphism (C825T) of the G protein beta3-subunit gene has been associated with low renin hypertension in whites. The aim of this study was to examine the C825T polymorphism in relation to hypertension in a population-based study of black people of African origin who have high prevalence of low renin, salt-sensitive hypertension. A total of 428 men and women, aged 40 to 59 years (270 Caribbeans and 158 West Africans), who took part in a population-based survey were studied. All were blacks and first-generation immigrants. The C825T polymorphism was detected by polymerase chain reaction followed by restriction-enzyme digestion. The prevalence of hypertension (supine blood pressures >/=160 systolic and/or 95 mm Hg diastolic or on drug therapy) was 43%. The distribution of the genotypes (CC, CT, and TT) was in Hardy-Weinberg equilibrium with observed frequencies of 4.0% (n=17), 33.6% (n=144), and 62.4% (n=267), respectively. Allele frequencies were 20.8% for C and 79.2% for T. No difference was detected between Caribbeans and West Africans. A 3-fold higher risk of hypertension was found among the carriers of the T variant both as heterozygotes (odds ratio [OR], 3.43 [95% CI, 0.94 to 12.4]) and homozygotes (OR, 3.87 [95% CI, 1. 09 to 13.8]). The estimate of effect and the blood pressure values in the groups carrying the T variant suggested a dominant model for the T allele. This was confirmed by a significant association between the T allele and hypertension (OR, 3.71 [95% CI, 1.05 to 13. 1]), even when adjusted for age, sex, and body mass index (OR, 4.14 [95% CI, 1.11 to 15.4]). The study shows, for the first time, a high frequency of the 825T allele in black people, and it provides evidence that the T allele may be a susceptibility factor for the development of hypertension in blacks. Given the high frequency of the T allele, even a 2-fold increased risk of hypertension among the carriers of the T allele might account for 44% of the cases of hypertension in blacks.

Adult↗
PubMed1999

Physical map and organization of chromosome 7 in the rice blast fungus, Magnaporthe grisea.

The rice blast fungus Magnaporthe grisea is a highly destructive plant pathogen and one of the most important for studying various aspects of host-plant interactions. It has been widely adopted as a model organism because it is ideally suited for genetic and biological studies. To facilitate map-based cloning, chromosome walking, and genome organization studies of M. grisea, a complete physical map of chromosome 7 was constructed using a large-insert (130 kb) bacterial artificial chromosome (BAC) library. Using 147 chromosome 7-specific single-copy BAC clones and 20 RFLP markers on chromosome 7, 625 BAC clones were identified by hybridization. BAC clones were digested with HindIII, and fragments were size separated on analytical agarose gels to create DNA fingerprints. Hybridization contigs were constructed using a random cost algorithm, whereas fingerprinting contigs were constructed using the software package FPC. Results from both methods were generally in agreement, but numerous anomalies were observed. The combined data produced five robust anchored contigs after gap closure by chromosomal walking. The genetic and physical maps agreed closely. The final physical map was estimated to cover >95% of the 4.2 Mb of chromosome 7. Based on the contig maps, a minimum BAC tile containing 42 BAC clones was created, and organization of repetitive elements and expressed genes of the chromosome was investigated.

Algorithms↗
PubMed1999

[Studies on the spectrum features of nasalized vowels].

OBJECTIVE: To study the spectrum features of nasalized vowels and set up effective indexes to reflect the features. METHODS: The acoustic features of 100 children's speech, aged 5 to 12 years old, consisted of 40 unrepaired cleft palate children, 28 VPI children and 32 normal children, were studied by the application of digital spectrograph. RESULTS: No significant changes in the frequency of inherent formants of each vowel, appearance of one relatively fixed extra formant in the low frequency area, and the energy of high frequency area being damped obviously were the main spectrum features of nasalized vowels. CONCLUSION: There are three main features on the spectrums of nasalized vowels compared to that of oral vowels. Nasal resonance index (NRI) can effectively distinguish the extra formant in low frequency area of oral vowel /a/ from nasalized vowel /a/. Energy damping index (EDI) can effectively reflect that the energy of high frequency area of each nasalized vowel is damped obviously.

Child↗
PubMed1999

[The changes of transforming growth factor beta 1 in periodontal tissue during orthodontic tooth movement].

OBJECTIVE: To observe the distribution and change of transforming growth factor beta 1 (TGF-beta 1) in periodontal tissue and understand the role of TGF-beta 1 in orthodontic tooth movement. METHODS: Apply force on right maxillary first molars in rats, and examine the decalcified alveolodental connected tissue in different stage of tooth movement with immunohistochemical staining technique (SP method). RESULTS: TGF-beta 1 exists in normal periodontal tissue. The expression of it in periodontium increases during orthodontic tooth movement. Especially from 5 to 10 days after force application, the expression at tension side is much more than those at pressure side. CONCLUSION: TGF-beta 1 plays an important role in remodeling of periodontal tissue during orthodontic tooth movement, and can powerfully promote bone formation.

Animals↗
PubMed1999

[Origin and progress of myelodysplastic syndrome with hypoplasia].

OBJECTIVE: To study the origin and progress of myelodysplastic syndrome (MDS) with hypoplasia. METHODS: The data of twenty-five cases of hypomyeloplastic MDS diagnosed by our department in the last ten years were analyzed. 17 of the 25 cases were followed up for a long time. RESULTS: (1) The percentage of hypomyeloplastic MDS was 11.4% of the total 219 MDS patients. The median age of the 25 cases was (44.8 +/- 14.7) years. (2) FAB subtype: There were 11 cases of RA and 14 of RAEB. (3) Hypomyeloplastic MDS seems to be a developmental phase in the clinical course in some of the patients and not a special type of MDS. Hyper- and hypo-myeloplasia could be transformed from one to another. The transformation of myelodysplasia could occur either in the same or and different FAB subtype. (4) Seven of the seventeen cases transformed to acute leukemia (41.2%), 6 cases were AML and 1 was ALL. 3 of the 7 cases transformed to hypomyeloplastic leukemia and the remaining 4 transformed to hypermyeloplastic leukemia. (5) The median time from the diagnosis of RAEB to leukemia transformation, was 27 months in 7 cases with hypoplastic RAEB. (6) No relationship was found between therapeutic medicines and development of hypomyeloplastic MDS. CONCLUSION: It is suggested that hypomyeloplastic MDS is probably a developmental phase in the clinical course of MDS, but not a special type.

Adult↗
PubMed1999

[The effect of inhaled ipratropium bromide on airway and lung tissue muscarinic receptors in a rat model of COPD].

OBJECTIVE: To observe the effect of inhaled ipratropium bromide on airway and lung tissue muscarinic receptors (MR) in a rat model of chronic obstructive pulmonary disease (COPD). METHODS: The rat model of COPD was established by chronic exposure with high concentrations of SO(2) gas, COPD rats inhaled aerosolized 0.025% ipratropium bromide solution 10 ml (twice/d, 20min/time). The MR was determined by radioligand binding studies with (3)H-QNB as the ligand. RESULTS: Compared with that of control, there was a marked increase in MR density on day 30 of treatment with ipratropium but not on day 5. The MR density decreased and close to normal level on the 6th day after cessation of regular therapy with inhaled ipratropium for 30 days. No significant difference was observed in antagonist affinity (Kd) among different time groups of ipratropium therapy. CONCLUSIONS: Chronic exposure to the anticholinergic agent ipratropium bromide produces an up-regulation of airway MR. The airway MR density can recover to normal when treatment stopped. Up-regulation of airway MR is associated with transient bronchoconstriction following cessation of regular ipratropium therapy and lung function deteriorated following long-term inhaled ipratropium bromide.

Administration, Inhalation↗