Biomedical subjects

T Hu

Publications and source records attributed to T Hu.

At least 73 records · Page 4Linked to original sources

PubMed1999

[Ischemic preconditioning reduces lung ischemia reperfusion injury in vivo rabbits].

Thirty male Japanese white rabbits were randomized into two groups. Fifteen rabbits were treated with ischemic preconditioning(their left lung hilus clamped for 10 min and released for 15 min; Group IP). Fifteen rabbits were not treated with ischemic preconditioning(Group C). Then the left lung hilus of both groups were occlused for 60 min and reperfused for 60 min. The results were that after 60 min of reperfusion, in Group IP, the contents of angiotensin II (Ang II) and artery oxygen tension(PaO2) in blood samples and the contents of superoxide dismutase in lung tissue were significantly higher, while the mean pulmonary artery pressure in blood samples, the wet/dry ratio and malondialdehyde content in lung tissue were significantly lower than those in Group C; Histological findings showed less damage in Group IP. It is suggested that lung ischemic preconditioning can reduce normothermic rabbit lung ischemia-reperfusion injury.

Angiotensin II↗

PubMed1998

cDNA cloning and analysis of the expression of nucleoporin p45.

The p62 complex is an assembly of four O-linked glycoproteins (p62, p58, p54, and p45) localized in the central region of the nuclear pore complex. It has been suggested to provide a substrate binding site near the central gated channel of the pore during nuclear protein import. The sequences of p62, p58, and p54 from rat have been reported previously. We have now carried out cDNA cloning of rat p45. The authenticity of the p45 clone was confirmed by two-dimensional gel analysis of the in vitro translated product of this clone. Sequence comparison showed that p45 is mostly identical to the amino terminal four-fifths of p58. p45 contains an N-terminal FG (Phe-Gly) repeat region, a middle coiled-coil region, and a truncated C-terminal FG repeat region (compared to p58). The sequence data and genomic Southern hybridization results strongly support the possibility that p45 and p58 are generated by mRNA alternative splicing. The sequences of three other p58-related cDNA clones indicate that the p58/p45 gene transcript gives rise to additional alternatively spliced mRNAs in mammalian cells. Interestingly, the expression level of p45 relative to p58 varies in different cultured cell lines, indicating that the p62 complex is heterogeneous with respect to these two subunits.

Amino Acid Sequence↗

PubMed1998

Extracellular Ca2+ regulates the respiratory burst of human neutrophils.

The role of extracellular calcium in the activation of respiratory burst in human neutrophils was studied by using the receptor agonist, N-formyl-methionyl-leucyl-phenylalanine (fMLP), and the activator of protein kinase C phorbol myristate acetate (PMA). The level of intracellular free calcium was measured by using both cell suspensions and single cells in the presence and absence of extracellular calcium. The Ca2+-ATPase inhibitor, thapsigargin, was used to activate higher Ca2+ influx, while a novel calcium channel blocker, panax notoginseng saponins (PNGS) was used to block the Ca2+ entry from extracellular space during the responding period of cells. It was found that about two-thirds of the activation of respiratory burst initiated by the receptor agonist were attributed to the Ca2+ influx under normal physiological conditions. The higher Ca2+ influx resulted in tremendous enhancement of the intensity of respiratory burst initiated by fMLP and marked acceleration of the onset of the respiratory burst stimulated by PMA. It is evident that both intra- and extracellular Ca2+ are required for full activation of the respiratory burst of human neutrophils, and the Ca2+ influx from extracellular space plays an important role either in generation of reactive oxygen metabolites or in activation of protein kinase C.

Calcium↗

PubMed1998

Analysis of a core domain in Drosophila DNA topoisomerase II. Targeting of an antitumor agent ICRF-159.

To investigate the biochemical properties of individual domains of eukaryotic topoisomerase (topo) II, two truncation mutants of Drosophila topo II were generated, ND406 and core domain. Both mutants lack the ATPase domain, corresponding to the N-terminal 406 amino acid residues in Drosophila protein. The core domain also lacks 240 amino acid residues of the hydrophilic C-terminal region. The mutant proteins have lost DNA strand passage activity while retaining the ability to cleave the DNA and the sequence preference in protein/DNA interaction. The cleavage experiments carried out in the presence of several topo II poisons suggest that the core domain is the key target for these drugs. We have used glass-fiber filter binding assay and CsCl density gradient ultracentrifugation to monitor the formation of a salt-stable, protein-clamp complex. Both truncation mutant proteins can form a clamp complex in the presence of an antitumor agent, ICRF-159, suggesting that the drug targets the core domain of the enzyme and promotes the intradimeric closure at the N-terminal interface of the core domain. Furthermore, the salt stability of the closed protein clamp induced by ICRF-159 depends on the presence and closure of the N-terminal ATPase domain.

Adenosine Triphosphatases↗

PubMed1998

Identifying Lys359 as a critical residue for the ATP-dependent reactions of Drosophila DNA topoisomerase II.

Substituting Lys359 with either Gln or Glu in the highly conserved QTK-loop in the DNA gyrase B protein homologous domain of Drosophila topoisomerase II inactivates its catalytic activities. Although strand passage and DNA-dependent ATPase activities are affected in these mutant proteins, their DNA cleavage activity is comparable with the wild-type enzyme and can be stimulated to the same level by topoisomerase-targeting anticancer drugs. The sequence specificity in the DNA cleavage reaction remains unaltered for the mutant proteins. We have used both glass fiber filter binding assay and CsCl density gradient ultracentrifugation to monitor the formation of a salt-stable, protein-clamp complex. Both Gln and Glu mutant proteins can form a clamp complex in the presence of 5'-adenylyl-beta,gamma-imidodiphosphate, albeit with a lower efficiency than the wild-type enzyme. However, the mutant proteins can form a stable complex either in the presence of ATP or in the absence of any cofactors. These results are in an interesting contrast with the wild-type enzyme, which cannot form a stable complex under similar conditions. Our data suggest that Lys359 is critical for the catalytic activity of topoisomerase II and may have an important function in the ATP signaling process.

Adenosine Triphosphate↗

PubMed1998

A capitated model for a cross-section of severely mentally ill clients: hospitalization.

Hospitalization outcomes are examined in a three year random assignment controlled study of two capitated Integrated Service Agencies (ISAs) in California. Study participants were a cross-section of severely mentally ill clients. Using the flexibility of capitated funding, the urban ISA reduced inpatient length of stay and days, but not admissions. Elements of the capitated ISA model worked together to produce clinically appropriate and less costly use of inpatient services. At the rural ISA, admissions were reduced substantially during the first two years of the demonstration but not costs.

Adult↗

PubMed1998

[Regeneration of costal cartilage by pectus excavatum and thoracic cage remodeling].

In order to identify whether the regeneration of costal cartilage is the basis of post-surgical repair of pectus excavatum and thoracic cage remodeling, 151 cases were followed up for 0.25 to 14 years. The main procedures in treatment were 3 steps: To curve the mental strut as a bow, to repair the perichondrium as a tube, and to persist in post-operative therapy. The results showed that regeneration of the costal cartilages appeared 3 months postoperatively in the cases treated by this method. It was concluded that a satisfactory thoracic cage could be remodeled by improving the technique of repairing pectus excavatum and persisting in postoperative therapy according to the regeneration regularity.

Adolescent↗

PubMed1998

Treatment of atrophic cholecystitis by regulating the function of the spleen--a report of 50 cases.

Fifty cases of atrophic cholecystitis were treated mainly by regulation of the function of the spleen. Of them, 21 cases were cured, 18 markedly effective, and 7 effective. The total effective rate was 92.0%. By comparison of results of ultrasonography B performed before and after treatment, it was shown that both the longitudinal and transverse inner diameters of gallbladder cross section increased evidently, and the condition of atrophy was improved remarkably after treatment.

Adolescent↗

PubMed1998

Reversed-phase high-performance liquid chromatographic measurement of the P-aminobenzoic acid synthesized by Streptococcus sanguis.

OBJECTIVE: This study investigated the biosynthesis of P-aminobenzoic acid by Streptococcus sanguis and the role of P-aminobenzoic acid in the interaction between Streptococcus sanguis and Streptococcus mutans. METHODS: A reversed-phase high-performance liquid chromatographic technique was used to analyze the P-aminobenzoic acid synthesized by Streptococcus sanguis in an anaerobic atmosphere. RESULTS: The results showed, that (1) the chromatographic method established in this study had good linear relation and the average recovery of P-aminobenzoic acid was 80%, and (2) Streptococcus sanguis did synthesize P-aminobenzoic acid, and the mean concentration of P-aminobenzoic acid was 1.23 micrograms/mL. CONCLUSIONS: The results of this study will help further studies of the factors that may have effects on P-aminobenzoic acid synthesis by Streptococcus sanguis and on the role of P-aminobenzoic acid in the microbial homeostasis of dental plaque.

4-Aminobenzoic Acid↗

PubMed1998

[Esophageal reconstruction using ilecolon in children--a report of ten cases].

The use of the ileocolon as a substitute for esophagus in children has been a well-established surgical procedure. Between 1992 and 1995, ten retrosternal esophageal substitutions using an ileocolic interposition were performed. The ages of the children ranged from 2 to 8 years. The esophageal strictures were secondary to ingestion of caustic liquid. No death occurred in the intra- and post-operation period. Cervical ileoesophageal anastomotic leaks took place in 2 cases as the early major postoperative complications, which healed spontaneously. Three cases of ileoesophageal anastomotic strictures were noted in the follow-up period. The surgical indications, the treatments of anastomotic leaks and strictures, and the importance of long-term follow-up were discussed.

Burns, Chemical↗

PubMed1998

[Myocardioprotective effects of preconditioning in patients undergoing open heart operation].

OBJECTIVE: To investigate the myocardial protective effects of ischemic preconditioning (IP) on adult patients who undergoing prolonged open heart operation for complex heart diseases. METHODS: 30 patients were evenly divided into two groups at random. IP was elicited twice for 2 minutes ischemia from occlusion of vena cava and aorta followed by 3 minutes of reperfusion under cardiopulmonary bypass. Dynamic changes of ATP and purine metabolites in myocardium were measured. Electrocardiogram, leakage of myocardial enzymes, activities of SOD and LPO in serum and myocardial mechanics were investigated. RESULTS: IP reduced ATP repletion and maintained a higher ATP content in ischemic myocardium (P < 0.05 vs control group at 30, 60, and 90 minutes of ischemia). Reduced inosine content was found in IP group (P > 0.05). The inosine/adenosine ratio at 30, 60 and 90 minutes of ischemia was 4.2 vs 14.1, 17.6 vs 28.2, 29.2 vs 71.3 for the IP and control groups, respectively, P < 0.05). There were also significant differences between the two groups in changes of ST-segment shifting, myocardial contractile and early postoperative recovery. CONCLUSIONS: IP can reduce ischemia-reperfusion injury on prolonged ischemic myocardium in humans even when combined with cold cardioplegia. Decreased inosine production and inosine/adenosine ratio in ischemic myocardium may be an important mechanism of IP, by which the production of oxygen free radicals are decreased during early reperfusion.

Adenosine Triphosphate↗

PubMed1998

[Treatment of acute optic neuritis with high dose of prednisone].

OBJECTIVE: The benefit of glucocorticoid for the treatment of acute optic neuritis remains controversial. The efficacy of oral prednisone in 12 patients (14 eyes) with acute optic neuritis was reviewed. METHODS: The time of visual symptoms before treatment was 3-15 days. The visual acuities were worse than 0.1 in all patients, with positive relative afferent pupillary defect. Visual field defect and delay latency of P100 in pattern VEP were also found. The regimen of glucocorticoid therapy was oral prednisone, starting with 160 mg daily followed by reducing the dosage by 20 mg every three days until 40 mg per day was attained and then tapering the dosage at 70 mg every other day until stoppage of the drug. The treatment was 3-11 months and 9 patients were followed up more than one year. RESULTS: The visual acuities improved rapidly and stable. After 4 days, the visual acuity was 0.2 or better in 10 eyes. It was better than 0.6 in 12 eyes at 15 days. At 6 months, all had the visual acuity better than 0.7, with 85.7% equal or better than 1.0. CONCLUSIONS: The regimen of oral prednisone beginning with 160 mg followed by tapering for three months would be feasible. Pattern VEP was a sensitive and credible sign for evaluating the extent of demyelination.

Acute Disease↗

PubMed1998

[The mechanisms of antioxidant against inflammatory lesion in animal oral mucosa. II. A study of glutathione peroxidase].

In order to understand the mechanisms of superoxide dismutase (SOD) against inflammatory lesion in hamster cheek pouch, glutathione peroxidase (GPx) activity in the cheek pouch mucosa was assayed in different time. The efficacy of GPx scavenging lipid peroxide was also measured. In the SOD group GPx activity decreased significantly in the early stage (8 h). But the level of lipid peroxide in the SOD group not increase at the same time. The results of the model group were contrary. It was implied that exigenous SOD scavenged lipid peroxide in the oral mucosa sufficiently in stead of GPx.

Animals↗

PubMed1998

[Study on the biosynthesis of para-aminobenzoic acid by S. sanguis. I. Establishment of a reversed-phase high-performance liquid chromatography].

In order to study the synthesis of para-aminobenzoic acid (PABA) by S. mutans and the role of PABA in the interaction between S. mutans and S. sanguis, a reversed-phase high-performance liquid chromatography (RP-HPLC) for analysis of PABA was developed. The results showed that the optimal chromatographic parameters were flow rate of 1.5 ml/min, T = 55 +/- 2 degrees C, methanol/phosphate buffer of 10/90(by vol) (pH 2.2 0.1 mol/L), m-hydroxybenzoic acid as an internal standard. The method is simple, rapid accurate and useful.

4-Aminobenzoic Acid↗

PubMed1998

[Study on the biosynthesis of para-aminobenzoic acid by S. sanguis. II. Qualitative and quantitative analysis].

In this study, the method established in paper 1 was used to analyze PABA synthesized by S. sanguis S34. The results showed: 1. S. sanguis S34 did synthesize PABA and the mean concentration of PABA was 1.236 micrograms/ml. 2. the components had good linear relation and average recovery was 80%. The results of this paper will be helpful to studying influencing factors on PABA synthesis of S. sanguis and the roles of PABA in microbial homeostasis of dental plaque.

4-Aminobenzoic Acid↗

PubMed1998

[Investigation on the luminescence properties of Er ions in Er-doped sol-gel silica glasses].

Er-doped sol-gel silica glasses which have room temperature photoluminescence at 1.54 microm and doped concentration of 10(20)/cm(3) have been prepared. The examination results Indicated: (1) PL spectrum has largest intensity at the 0.5W% doped concentration; (2) the intensity of PL decreased 74%, when the temperature raised form 4K to 300K; (3) The Er ion and O ions formed complexes with coordinated numbers of 8 or 9.

English Abstract↗

PubMed1997

Observations on the treatment of natural haemosporidia infections by total alkaloid of Peganum harmala L. in cattle.

Eighty two cattle naturally infected with haemosporidians were treated with total alkaloid hydrochloride of Peganum harmale L. (0.5 mg/kg/day). Fifty eight cases with Theileria sergenti showed a cure rate of 86%; thirteen cases with Theileria annulata showed a cure rate of 85%; eight cattle infected with Babesia bigemina showed a cure rate of 88% and three cases of Anaplasma marginale were completely cured. The results suggested that the curative effect of total alkaloid of P. harmale was better than that of diminazene aceturate and produced minimal side effects. The alkaloid could also be administered to pregnant animals. It was concluded that the total alkaloid of P. harmale showed a marked effect as a treatment for haemosporidican infections in cattle.

Alkaloids↗

PubMed1997

Effect of total alkaloid of Peganum harmala L. in the treatment of experimental haemosporidian infections in cattle.

Cattle experimentally infected with Babesia bigemina or Theileria sergenti or mixed infestations of the two parasites were treated with Total Alkaloid of Peganum harmala L. The results showed that treatment was effective against B. bigemina infection, had a marked effect on the course of infection with T. sergenti and some effect on the course of the mixed infection.

Alkaloids↗