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Biomedical subjects

Hui Zhao

Publications and source records attributed to Hui Zhao.

141 records · Page 8Linked to original sources
PubMed2002

Visualization of Proteus mirabilis within the matrix of urease-induced bladder stones during experimental urinary tract infection.

The virulence of a urease-negative mutant of uropathogenic Proteus mirabilis and its wild-type parent strain was assessed by using a CBA mouse model of catheterized urinary tract infection. Overall, catheterized mice were significantly more susceptible than uncatheterized mice to infection by wild-type P. mirabilis. At a high inoculum, the urease-negative mutant successfully colonized bladders of catheterized mice but did not cause urolithiasis and was still severely attenuated in its ability to ascend to kidneys. Using confocal laser scanning microscopy and scanning electron microscopy, we demonstrated the presence of P. mirabilis within the urease-induced stone matrix. Alizarin red S staining was used to detect calcium-containing deposits in bladder and kidney tissues of P. mirabilis-infected mice.

Animals↗
PubMed2002

Murine model of gastrointestinal ischemia associated with complement-dependent injury.

Gastrointestinal ischemia-reperfusion (I/R) injury is often associated with remote tissue injury. Complement activation plays an important role in local and remote tissue injury associated with gastrointestinal I/R. We developed a new murine model of gastrointestinal I/R that has complement-dependent local and remote tissue injury. Twenty, but not thirty, minutes of gastrointestinal ischemia followed by 3 h of reperfusion induced a significant loss of intestinal lactate dehydrogenase that was significantly prevented by a murine anti-murine C5 monoclonal antibody. Anti-C5 also significantly decreased neutrophil infiltration into the gut and lung. Gastrointestinal I/R significantly increased pulmonary intercellular adhesion molecule-1 mRNA and protein expression that was significantly inhibited by anti-C5. Pulmonary macrophage inflammatory protein-2 mRNA was significantly induced by gastrointestinal I/R and inhibited by anti-C5 treatment. These data demonstrate that brief periods of murine gastrointestinal I/R activate complement, leading to tissue injury and neutrophil accumulation. Anti-C5 treatment attenuates tissue injury, neutrophil recruitment, and leukocyte adherence molecule and chemokine expression in the mouse. This model will be well suited to investigate the role of complement-mediated tissue injury and gene expression after gastrointestinal I/R.

Animals↗
PubMed2002

Comprehensive and definitive structural identities of Pneumocystis carinii sterols.

Pneumocystis causes a type of pneumonia in immunodeficient mammals, such as AIDS patients. Mammals cannot alkylate the C-24 position of the sterol side chain, nor can they desaturate C-22. Thus, the reactions leading to these sterol modifications are particularly attractive targets for the development of drugs against fungal and protozoan pathogens that make them. In the present study, the definitive structures of 43 sterol molecular species in rat-derived Pneumocystis carinii were elucidated by nuclear magnetic resonance spectroscopy. Ergosterol, Delta(5,7) sterols, trienes, and tetraenes were not among them. Most (32 of the 43) were 24-alkylsterols, products of S-adenosyl-L-methionine:C-24 sterol methyl transferase (SAM:SMT) enzyme activity. Their abundance is consistent with the suggestion that SAM:SMT is highly active in this organism and that the enzyme is an excellent anti-Pneumocystis drug target. In contrast, the comprehensive analysis strongly suggest that P. carinii does not form Delta(22) sterols, thus C-22 desaturation does not appear to be a drug target in this pathogen. The lanosterol derivatives, 24-methylenelanost-8-en-3 beta-ol and (Z)-24-ethylidenelanost-8-en-3 beta-ol (pneumocysterol), previously identified in human-derived Pneumocystis jiroveci, were also detected among the sterols of the rat-derived P. carinii organisms.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Free and total insulin-like growth factor (IGF)-I levels decline during fasting: relationships with insulin and IGF-binding protein-1.

We have previously demonstrated that IGF-binding protein-1 (IGFBP-1) levels rise steadily during fasting, following an inverse relationship with insulin. The function of the IGFBP-1 rise is unknown, but it has been hypothesized that IGFBP-1 serves as a glucose counterregulatory hormone during fasting and hypoglycemia by binding free IGFs, thus inhibiting IGF interactions with IGF receptors. Our objective in this study was to determine levels of free and total IGFs during fasting together with their interrelationships with simultaneous IGFBP-1, insulin, and glucose levels. Our patient population consisted of 22 children, aged 6 months to 15 yr, who underwent diagnostic fasting studies in the General Clinical Research Center. Blood was sampled at baseline and at 6-h intervals for glucose, IGFBP-1, free and total IGF-I, and insulin. The fasting studies lasted 14-40 h and were terminated at a glucose concentration of less than 50 mg/dl (n = 11) or for the completion of the allotted fasting duration (n = 11). Of the children studied, 11 had ketotic hypoglycemia, 8 had no disorder, 2 had steroid-induced adrenal suppression, and 1 had recovered transient hyperinsulinism. During fasting, IGFBP-1 levels rose above mean initial levels of 27.1 +/- 13.4 ng/ml to a mean of 318.4 +/- 29.9 ng/ml at the end point (P < 0.001). Insulin levels declined from a mean initial level of 7.4 +/- 1.3 mU/ml to a mean level of 1.4 +/- 0.4 mU/ml at the end point (P < 0.001). Concomitantly, free and total IGF-I levels declined from initial levels of 0.48 +/- 0.08 and 180.3+/- 27 ng/ml, respectively, to mean levels of 0.10 +/- 0.02 ng/ml (P < 0.001) and 119.3 +/- 22 ng/ml (P = 0.001), respectively, at the end point. Levels of free IGF-I were inversely associated with IGFBP-1 over the course of fasting (P = 0.002). Similarly, total IGF-I was negatively associated with IGFBP-1 (P = 0.01). We conclude that free and total IGF-I levels decline steadily over the course of fasting. This decline in free IGF-I appears to be the result of the steady rise in IGFBP-1 that occurs as insulin declines. We speculate that the decline in IGF levels, controlled by the rise in IGFBP-1, serves to protect against possible insulin-like activity of the IGFs during fasting.

Adolescent↗
PubMed2002

Neuroimmunal regulation of electroacupuncture (EA) on the traumatic rats.

EA has a wide range of function, many of them is mediated by the release of the endogenous opioid peptides. Using surgical traumatic stress model, it was observed that EA could improve the depression of cell mediated immune response. Based on the above results, we focused our work on the elucidation of the mechanism of EA in the central nervous system. The results showed that trauma amplified the activity of peritoneal macrophage, but inhibited Orphanin FQ and its receptor NP4 transcripts in the central nervous system, in the mean time, IL-1beta transcripts in the central nervous system was also augmented. EA stimulation of"Zusanli" (St. 36) and "Lanwei" (Extra. 37) points could inhibit all the above responses, but it had no influence on the normal rat. The results suggested that EA could modulate immune response via the interaction between Orphanin FQ and IL-1beta.

Animals↗
PubMed2002

[Sedative and anticonvulsant effect of jujuboside A]

OBJECTIVE: To study the sedative effects of Jujuboside A (JuA) on the Central Nervous System of mice. METHODS: Using a novel jiggle-cage test, we compared the sedative effect of JuA with that of Diazepam (DZP) both with a single and cumulative dose of JuA. We also assessed the anticonvulsant effect of JuA on pentylenetetrazol (PTZ)-induced seizures in mice. RESULTS: JuA significantly decreased total activity intensity and increased the quiet state time of mice. The sedative effects of JuA were more stable and more lasting than that of DZP. However, JuA failed to resist and delay the induced seizure activity in mice. CONCLUSION: Though JuA has sedative effects on mice CNS, it has no anticonvulsant effect on PTZ-induced seizures.

Journal Article↗
PubMed2002

Immunomodulatory activity of orphanin FQ/nociceptin on traumatic rats.

AIM: To explore the neuro-immune modulatory effect of orphanin FQ/nociceptin (OFQ) and opioid receptor like 1 (ORL1) receptor on the traumatic rats. METHODS: The quantitative method of immuno-cytochemistry and i n situ hybridization combined with cytokine bioassay were used to detect the expression of endogenous OFQ and ORL1 and the production of interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) from peritoneal macrophage. RESULTS: Strong signals for both OFQ immuno-reactive cells and ORL1 mRNA were detected in cerebral cortex, hippocampus, and hypothalamus in normal condition, whereas they were significantly reduced after trauma (P<0.05). However, the production of IL-1 and TNF-alpha from peritoneal macrophage was increased, when expressed as percentage of enhancement, the increment attained to 233 % and 521 % (sample dilution 1:4), 195 % and 566 % (1:8), 233 % and 757 % ( 1:16), 214 % and 622 % (1:32), respectively, after trauma. After icv injection of OFQ at doses of 0.055 nmol, 0.55 nmol, and 2.75 nmol, the units of IL-1 and TNF-alpha were reversed (P<0.05); however, the action of OFQ (0.55 nmol) was blocked by ORL1 selective antagonist [phe1psi(CH2-NH)Gly2]nociceptin-(1-13)-NH2. CONCLUSION: OFQ and ORL1, the new opioid peptide system, are involved in the immune response elicited by traumatic stress.

Animals↗
PubMed2002

[Preliminary experience of video-mediastinoscopy in clinical application].

OBJECTIVE: To determine the value of video-mediastinoscopy in clinical application. METHODS: The clinical data of 54 patients receiving video-mediastinoscopy were reviewed retrospectively. This operation consisted of cervical mediastinoscopy in 44 patients, parasternal mediastinoscopy in 6, and combined procedures in 4. Of these patients, 18 underwent video-mediastinoscopy for the evaluation of undifferentiated mediastinal disease. Thirty-six patients with suspected lung cancer showed enlarged mediastinal lymph nodes radiographically in the chest and underwent video-mediastinoscopy. RESULTS: Seventeen of 18 patients with undetermined mediastinal diseases had a definitive pathologic diagnosis, with an accuracy of 94.4% (17/18). In the 36 patients with suspected lung cancer, 22 were positive, and 14 negative. In the negative patients who underwent thoracotomy with resection, mediastinal lymph nodes revealed no evidence of metastasis. There were no postoperative complication and deaths. CONCLUSION: Video-mediastinoscopy as a highly effective and safe procedure could be used in the diagnosis and staging of thoracic diseases.

Adolescent↗
PubMed2002

[Electronic fiberesophagoscopy in video-assisted thoracoscopic surgery for benign esophageal diseases].

OBJECTIVE: To evaluate the effect of electronic fiberesophagoscopy in video-assisted thoracoscopic surgery for benign esophageal diseases. METHODS: We determined the position of lesion, separated the lesion from the esophageal wall, resected the lesion and protected the esophageal mucosa during the process of video-assisted thoracoscopic surgery for benign esophageal diseases. RESULTS: Thirty-six patients with benign esophageal disease underwent the operation successfully and recovered uneventfully. There was no operative death or severe perioperative complications such as esophago pleural fistula. Two patients were changed to undergo thoracotomy. CONCLUSIONS: Electronic fiberesophagoscopy is an essential equipment in video-assisted thoracoscopic surgery for benign esophageal diseases. It should be adopted as a routine equipment to ensure the accuracy, safety, reliability and convenience of this kind of operations.

Adolescent↗
PubMed2002

[Allelopathic potential of volatile oil from Mikania micrantha].

Mikania micrantha, an exotic plant species, is an important weed in south China. The volatile oil of the weed species had significant biological activities on plants and their pathogens, particularly Pyricularia grisea. The results showed that the seeding growth of 6 plant species decreased obviously when exposed to increasing concentration (200, 400, 800, 1600 mg.L-1) of the volatile oil. The fresh weight of all test plants decreased, and the emergence of all test plants delayed for 1-2 days under soil treatment (2500 g.hm-2). The inhibitory effect of volatile oil of M. micrantha at its medium concentration was the most strong on Pyricularia grisea; secondary on Fusarium oxysporum; but weak on Phytophthora nicotianae. The inhibitory rate was 53.38%, 28.66% and 18.69% for the three plant pathogens, respectively.

Ascomycota↗
PubMed1999

Identification of protease and rpoN-associated genes of uropathogenic Proteus mirabilis by negative selection in a mouse model of ascending urinary tract infection.

Proteus mirabilis, a motile gram-negative bacterium, is a principal cause of urinary tract infections in patients with functional or anatomical abnormalities of the urinary tract or those with urinary catheters in place. Thus far, virulence factors including urease, flagella, haemolysin, various fimbriae, IgA protease and a deaminase have been characterized based on the phenotypic traits conferred by these proteins. In this study, an attempt was made to identify new virulence genes of P. mirabilis that may not have identifiable phenotypes using the recently described technique of signature-tagged mutagenesis. A pool of chromosomal transposon mutants was made through conjugation and kanamycin/tetracycline selection; random insertion was confirmed by Southern blotting of chromosomal DNA isolated from 16 mutants using the aphA gene as a probe. From the total pool, 2.3% (9/397) auxotrophic mutants and 3.5% (14/397) swarming mutants were identified by screening on minimal salts agar and Luria agar plates, respectively. Thirty per cent of the mutants, found to have either no tag or an unamplifiable tag, were removed from the input pool. Then 10(7) c.f.u. from a 96-mutant pool (approximately 10(5) c.f.u. of each mutant) were used as an input pool to transurethrally inoculate seven CBA mice. After 2 d infection, bacteria were recovered from the bladders and kidneys and yielded about 10(5) c.f.u. as an output pool. Dot blot analysis showed that two of the 96 mutants, designated B2 and B5, could not be hybridized by signature tags amplified from the bladder output pool. Interrupted genes from these two mutants were cloned and sequenced. The interrupted gene in B2 predicts a polypeptide of 37.3 kDa that shares amino acid similarity with a putative protease or collagenase precursor. The gene in B5 predicts a polypeptide of 32.6 kDa that is very similar to that encoded by ORF284 of the rpoN operon controlling expression of nitrogen-regulated genes from several bacterial species. The virulence of the two mutants was tested further by co-challenging CBA mice with each mutant and the parental strain. After 1 week of infection, the B2 and B5 mutants were recovered in numbers 100-fold and 1000-fold less than the parental strain, respectively. Using an in vitro assay, it was shown that the B2 mutant had significantly less (P = 0.0001) extracellular protease activity than the wild-type strain. These findings demonstrate that signature-tagged mutagenesis is a viable approach to identify bacterial genes associated with the ability to infect the urinary tract.

Amino Acid Sequence↗
PubMedDate not supplied

Sterol composition of Pneumocystis jirovecii with blocked 14alpha-demethylase activity.

Several drugs that interact with membrane sterols or inhibit their syntheses are effective in clearing a number of fungal infections. The AIDS-associated lung infection caused by Pneumocystis jirovecii is not cleared by many of these therapies. Pneumocystis normally synthesizes distinct C28 and C29 24-alkylsterols, but ergosterol, the major fungal sterol, is not among them. Two distinct sterol compositional phenotypes were previously observed in P. jirovecii. One was characterized by delta7 C28 and C29 24-alkylsterols with only low proportions of higher molecular mass components. In contrast, the other type was dominated by high C31 and C32 24-alkylsterols, especially pneumocysterol. In the present study, 28 molecular species were elucidated by nuclear magnetic resonance analysis of a human lung specimen containing P. jirovecii representing the latter sterol profile phenotype. Fifteen of the 28 had the methyl group at C-14 of the sterol nucleus and these represented 96% of the total sterol mass in the specimen (excluding cholesterol). These results strongly suggest that sterol 14alpha-demethylase was blocked in these organisms. Twenty-four of the 28 were 24-alkylsterols, indicating that methylation of the C-24 position of the sterol side chain by S-adenosyl-L-methionine:sterol C-24 methyl transferase was fully functional.

Cytochrome P-450 Enzyme Inhibitors↗
PubMedDate not supplied

SBD.4 stimulates regenerative processes in vitro, and wound healing in genetically diabetic mice and in human skin/severe-combined immunodeficiency mouse chimera.

In search of novel angiostimulators, we performed a high-throughput screening of medicinal plants beneficial for blood circulation. From the panel of positive hits, Angelica sinensis was selected for further investigation. Purified down to a low-molecular-weight fraction and characterized by high-performance liquid chromatography-mass spectrometry, the material, named SBD.4A, revealed a particularly strong wound healing activity in the diabetic mouse wound-healing model, and in the human/severe combined immunodeficiency mouse chimera wound-healing model. In both models, SBD.4A compared favorably with the Food and Drug Administration-approved wound-healing drug becaplermin, suggesting that this botanical product could be a valuable treatment for difficult-to-heal wounds. Further high-performance liquid chromatography fractionation of SBD.4A yielded a hydrophilic fraction, which strongly stimulated endothelial cell proliferation, tridimensional endothelial cell network formation, as well as the proliferation of human dermal fibroblasts and type I collagen secretion. Because angiogenesis and fibroblast proliferation are essential for wound healing, we propose that this liquid chromatography-mass spectrometry-defined hydrophilic fraction is at least partially responsible for the wound-healing activity of SBD.4A.

Angelica sinensis↗
PubMedDate not supplied

Emission spectra of bioluminescent reporters and interaction with mammalian tissue determine the sensitivity of detection in vivo.

In vivo bioluminescence imaging depends on light emitted by luciferases in the body overcoming the effect of tissue attenuation. Understanding this relationship is essential for detection and quantification of signal. We have studied four codon optimized luciferases with different emission spectra, including enzymes from firefly (FLuc), click beetle (CBGr68, CBRed) and Renilla reniformins (hRLuc). At 25 degrees C, the in vitro lambda(max) of these reporters are 578, 543, 615, and 480 nm, respectively; at body temperature, 37 degrees C, the brightness increases and the firefly enzyme demonstrates a 34-nm spectral red shift. Spectral shifts and attenuation due to tissue effects were evaluated using a series of 20-nm bandpass filters and a cooled charge-coupled device (CCD) camera. Attenuation increased and the spectra of emitted light was red shifted for signals originating from deeper within the body relative to superficial origins. The tissue attenuation of signals from CBGr68 and hRLuc was greater than from those of Fluc and CBRed. To further probe tissue effects, broad spectral emitters were created through gene fusions between CBGr68 and CBRed. These resulted in enzymes with broader emission spectra, featuring two peaks whose intensities are differentially affected by temperature and tissue depth. These spectral measurement data allow for improved understanding of how these reporters can be used in vivo and what they can reveal about biological processes in living subjects.

Animals↗