Biomedical subjects

Z X Wu

Publications and source records attributed to Z X Wu.

At least 19 recordsLinked to original sources

PubMed2001

Role of intrinsic airway neurons in ozone-induced airway hyperresponsiveness in ferret trachea.

Exposure to ozone (O(3)) enhances airway responsiveness, which is mediated partly by the release of substance P (SP) from airway neurons. In this study, the role of intrinsic airway neurons in O(3)-induced airway responses was examined. Ferrets were exposed to 2 ppm O(3) or air for 1 h. Reactivity of isolated tracheal smooth muscle to cholinergic agonists was significantly increased after O(3) exposure, as were contractions to electrical field stimulation at 10 Hz. Pretreatment with CP-99994, a neurokinin type 1 receptor antagonist, partially abolished the O(3)-induced reactivity to cholinergic agonists and electrical field stimulation. The O(3)-enhanced airway responses were present in tracheal segments cultured for 24 h, a procedure shown to deplete sensory nerves while maintaining viability of intrinsic airway neurons, and all the enhanced smooth muscle responses were also diminished by CP-99994. Immunocytochemistry showed that the percentage of SP-containing neurons in longitudinal trunk and the percentage of neurons innervated by SP-positive nerve fibers in superficial muscular plexus were significantly increased at 1 h after exposure to O(3). These results suggest that enhanced SP levels in airway ganglia contribute to O(3)-induced airway hyperresponsiveness.

Acetylcholine↗

PubMed2001

Chronic smoking enhances tachykinin synthesis and airway responsiveness in guinea pigs.

This study tests the hypothesis that the bronchial hyperreactivity induced by chronic cigarette smoke (CS) exposure involves the increased expression and release of tachykinins and calcitonin gene-related peptide (CGRP) from afferent nerve fibers innervating the airways. In guinea pigs chronically exposed to CS (20 min twice daily for 14-17 d), peak response in total lung resistance to capsaicin (1.68 microg/kg, intravenously) was significantly greater than that evoked by the same dose of capsaicin in control (air-exposed) animals. This augmented response in CS-exposed animals was abolished after treatment with CP-99994 and SR-48968, the neurokinin (NK)-1 and NK-2 receptor antagonists, suggesting the involvement of tachykinins in chronic CS-induced airway hyperresponsiveness (AHR). Further, substance P (SP)-like immunoreactivity (LI) and CGRP-LI in the airway tissue were significantly greater in the CS animals than in the control animals. Finally, beta-preprotachykinin (PPT, a splice variant from the PPT A gene encoding tachykinins including SP and NKA) messenger RNA levels as measured by in situ hybridization histochemistry displayed a significant increase in jugular ganglion neurons but not in dorsal root or nodose ganglion neurons. These data suggest that chronic CS-induced AHR is related to an increase in SP synthesis and release in jugular ganglion neurons innervating the lungs and airways.

Analysis of Variance↗

PubMed2001

[Aneurysmal model induced by elastase].

OBJECTIVE: To induce the aneurysms by corrosion of aneurysmal wall with elastase, imitating clinical intracranial aneurysms patho-morhologically. METHODS: The elastase-corroded arterial segments were transplanted onto lateral walls of carotid arteries. Follow-up and pathological examination of the aneurysms were made at two weeks and one month after construction. RESULTS: The aneurysms formed by the transplantation of elastase-corroded arterial segments were found persistent or enlarge a little within one month. The aneurysms were purplish red and easy to rupture when exposed. The walls were deprived of elastic layer, and constructed by thin connective tissue. CONCLUSIONS: The aneurysms made by transplanting elastase-corroded arterial segments are simple to built, while morphological and pathological characteristics are demonstrated good clinical mimicry, we believe our aneurysm model may well substitute the most popularly used aneurysms made of venous pouches.

Aneurysm↗

PubMed2000

Airway hyperresponsiveness to cigarette smoke in ovalbumin-sensitized guinea pigs.

This study was carried out to determine if the bronchoconstrictive effect of cigarette smoke (CS) is enhanced when airway hyperresponsiveness is induced by ovalbumin (Ova) sensitization, and if so, whether an increase in endogenously released tachykinins is involved. The bronchoconstrictive effects of an acute CS inhalation challenge (15 ml; 50% concentration) were compared between guinea pigs sensitized with aerosolized Ova and matching control animals (receiving saline aerosol). In Ova-sensitized animals, there were marked increases in the numbers of eosinophils and neutrophils in the bronchoalveolar lavage fluid (BALF), which was accompanied by an elevated bronchomotor response to acetylcholine (ACh). The baseline lung resistance (RL) and dynamic pulmonary compliance (Cdyn) were not significantly different between the two groups; however, the same CS inhalation challenge evoked a significantly more intense bronchoconstriction in the Ova-sensitized group (control group: DeltaRL = 68 +/- 8%, DeltaCdyn = -26 +/- 6%; Ova group: DeltaRL = 425 +/- 76%; DeltaCdyn = -47 +/- 8%). The levels of substance P-like immunoreactivity (SP-LI) and calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) measured in the bronchoalveolar lavage (BAL) collected after CS inhalation challenge were also significantly greater in Ova-sensitized animals than in control animals. Furthermore, pretreatment with SR-48968, a selective antagonist of neurokinin-2 (NK(2)) receptor, inhibited more than 85% of the enhanced bronchomotor responses to CS challenge, but did not significantly reduce the airway hyperresponsiveness to ACh in Ova-sensitized guinea pigs. These results show that Ova sensitization induces airway hyperresponsiveness to inhaled CS, and that the endogenous tachykinins evoked by CS-induced activation of lung C fibers play a primary role in this augmented response.

Acetylcholine↗

PubMed2000

An external-sample liquid scintillation counting for 75Se and its application to selenoprotein detection.

An external-sample liquid scintillation (LS) counting for the gamma emitter 75Se has been developed. An expressly designed well-type LS vial and a 2,5-diphenyoxazole-1,4-bis(5-phenyl-2-oxazoyl)-benzene-xylene solution containing 35% tertrabutylzinn allow 75Se to be counted in a standard LS counter with counting efficiency up to 43.2%, much higher than that of conventional LS counting method. This external sample LS has a good count rate linearity and exhibits low background count rates. After in vivo labeling with [75Se]selenite, 75Se distributions and the Se-containing proteins present in tissues of male rat were investigated by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, external-sample LS and gamma-detector. Eight Se-containing proteins or protein subunits were detected to be Se-containing proteins or protein subunits in arterial wall, and their apparent molecular masses (Mr) were 76.4, 67.0, 57.4, 30.3, 25.4, 22.7, 21.7, and 15.1 kDa, respectively. In addition, eight 75Se-labeled proteins (Mr: 66.8, 57.0, 43.1, 30.0, 24.8, 19.8, 18.0, and 14.8 kDa) were found in brain homogenates, and nine 75Se-labeled proteins (Mr: 117.0, 78.0, 66.6, 57.2, 43.0, 38.1, 25.0, 20.1, and 18.0 kDa) were detected in testis homogenates. Some of them should be new biologically important selenoproteins that have not been identified so far.

Animals↗

PubMed1999

Airway hyperresponsiveness induced by chronic exposure to cigarette smoke in guinea pigs: role of tachykinins.

This study was carried out to determine whether tachykinins released from lung C-fiber afferents play a part in the bronchial hyperreactivity induced in guinea pigs by chronic exposure to cigarette smoke (CS). Two matching groups of young guinea pigs were exposed to either mainstream CS (CS group) or air (control group) for 20 min twice daily for 14-17 days. There was no difference in the baseline total pulmonary resistance (RL) between the two groups, but the baseline dynamic lung compliance was reduced ( approximately 19%) in CS animals. The responses of RL to intravenous injections of ACh, neurokinin (NK) A, and capsaicin were all markedly increased in CS animals; for example, ACh at the same dose of 5.06 microg/kg increased RL by 207% in the control group and by 697% (n = 8; P < 0. 001) in the CS group. The increased responsiveness was accompanied by significant increases in the numbers of neutrophils, eosinophils, and macrophages in the bronchoalveolar lavage fluid in CS animals. Pretreatment with SR-48968 and CP-99994, antagonists of NK(1) and NK(2) receptors, respectively, did not alter the response of RL to ACh in control animals, but it abolished the elevated bronchoconstrictive response in the CS animals. Furthermore, the immunoreactivities of substance P and calcitonin gene-related peptide in the bronchoalveolar lavage fluid collected after capsaicin challenge were significantly increased in CS animals. These results show that chronic exposure to CS induced airway mucosal inflammation accompanied by bronchial hyperreactivity in guinea pigs and that the tachykininergic mechanism plays an important role in this augmented responsiveness.

Acetylcholine↗

PubMed1997

The non-randomness of the distribution of Trichuris trichiura and Ascaris lumbricoides eggs in faeces and the effect of stirring faecal specimens.

Experiments were performed to describe the distribution of Trichuris trichiura and Ascaris lumbricoides eggs in faeces and to test for the effect of stirring faecal specimens prior to sampling. For each of 5 volunteers infected with A. lumbricoides and 7 volunteers infected with T. trichiura, helminth eggs were counted in 150 samples from a single stool specimen using the Kato-Katz smear technique. No significant differences between the distribution of eggs in samples from the surface and the centre of the specimens were found. Prior to stirring, eggs were found to be aggregately distributed in four of the specimens with T. trichiura and all of the specimens with A. lumbricoides. The distributions of eggs were not significantly altered by stirring the stool prior to sampling except in the case of one volunteer infected with A. lumbricoides for whom stirring reduced variability.

Animals↗

PubMed1997

Role of tachykinins in ozone-induced airway hyperresponsiveness to cigarette smoke in guinea pigs.

Acute exposure to ozone (O3) induces airway hyperresponsiveness to various inhaled bronchoactive substances. Inhalation of cigarette smoke, a common inhaled irritant in humans, is known to evoke a transient bronchoconstrictive effect. To examine whether O3 increases airway responsiveness to cigarette smoke, effects of smoke inhalation challenge on total pulmonary resistance (RL) and dynamic lung compliance (Cdyn) were compared before and after exposure to O3 (1.5 ppm, 1 h) in anesthetized guinea pigs. Before O3 exposure, inhalation of two breaths of cigarette smoke (7 ml) at a low concentration (33%) induced a mild and reproducible bronchoconstriction that slowly developed and reached its peak (DeltaRL = 67 +/- 19%, DeltaCdyn = -29 +/- 6%) after a delay of >1 min. After exposure to O3 the same cigarette smoke inhalation challenge evoked an intense bronchoconstriction that occurred more rapidly, reaching its peak (DeltaRL = 620 +/- 224%, DeltaCdyn = -35 +/- 7%) within 20 s, and was sustained for >2 min. By contrast, sham exposure to room air did not alter the bronchomotor response to cigarette smoke challenge. Pretreatment with CP-99994 and SR-48968, the selective antagonists of neurokinin type 1 and 2 receptors, respectively, completely blocked the enhanced responses of RL and Cdyn to cigarette smoke challenge induced by O3. These results show that O3 exposure induces airway hyperresponsiveness to inhaled cigarette smoke and that the enhanced responses result primarily from the bronchoconstrictive effect of endogenous tachykinins.

Acetylcholine↗

PubMed1997

Combinations of three immunological assays for detecting anti-Toxoplasma IgG in the sera of patients infected with Toxoplasma gondii.

Enzyme-linked immunosorbent assay (ELISA), Dot-ELISA and Dot-immunogold silver staining (Dot-IGSS) were simultaneously used to detect the specific IgG against Toxoplasma gondii in 65 patients infected with the protozoa. The positive rates were 86.51%, 92.51% and 98.64%, respectively. When ELISA and Dot-ELISA results were put together, the positive rate increased to 95.38%. When Dot-IGSS results were combined with those of ELISA or Dot-ELISA, the positive rate was raised to 100%. The difference in positive rate between ELISA and Dot-IGSS was significant (x2 = 6.93, p < 0.01), but no statistically significant differences were found between ELISA and Dot-ELISA or between Dot-ELISA and Dot-IGSS. Paired comparison of the reacting intensities of the sera in the 3 assays showed the correlations were highly significant (p < 0.001), with r = 0.608 between Dot-IGSS and Dot-ELISA, r = 0.8194 between Dot-IGSS and ELISA and r = 0.517 between Dot-ELISA and ELISA. Hence combination of different serological assays may increase their sensitivity and specificity for detecting the anti-Toxoplasma antibodies.

Animals↗

PubMed1997

The effects of temperature, light and water upon the hatching of the ova of Schistosoma japonicum.

Eggs of Schistosoma japonicum were obtained from infected patients' feces from Yujiang City, China to observe the effects of temperature, light and water on the hatching of eggs. The temperature of water and light played important roles on the hatching of S. japonicum, but the type of water did not. A constant temperature of 28 degrees C and electrical light produced the highest rate of hatching, and reproducible results, whereas a temperature of 4 degrees C or 37 degrees C, and the absence of light inhabited the hatching of eggs. The percentage of eggs hatched during the first 8 hours of 24 hours incubation was 94.90%, so that using the hatching rate of the first 8 hours could approximate the total hatching rate of samples.

Animals↗

PubMed1996

Dot-immunogold-silver staining in the diagnosis of cysticercosis.

Dot-immunogold-silver staining (Dot-IGSS) and Dot-ELISA were used, with Taenia solium cyst fluid antigen, to detect specific antibodies in the sera of patients with cysticercosis. All 40 confirmed cases of cysticercosis were found to be positive when tested by 2 methods. The average titer of the sera detected by Dot-IGSS was 1:27,470, which was significantly higher than that detected by Dot-ELISA. The false positive rates were 2% and 4% in 50 healthy controls for Dot-IGSS and Dot-ELISA, respectively, with a low titer of 1:20.

Antibodies, Helminth↗

PubMed1996

[Endotoxin causes release of calcitonin gene-related peptide (CGRP) from the isolated mesenteric arterial bed in rat].

Our previous work has shown that CGRP is released into the circulation during endotoxin or hemorrhagic shock in animals and septic shock in patients. We have also identified the blood vessels as a major source of production of circulating CGRP in the endotoxic rat. In the present study we determined whether ETX could directly trigger release of CGRP from CGRP-containing perivascular nerves in isolated mesenteric arterial bed (MAB) of rat. The results showed that ETX caused time- and concentration (10-100 micrograms/ml) -dependent release of CGRP. ETX (50 micrograms/ml) is increased by 20 fold CGRP in perfusate 10-15 min after ETX. Characterization of CGRP in perfusates by reverse-phase HPLC showed one predominant peak which coeluted with synthetic rat CGRP. Pretreated MAB with capsaicin or ruthenium red inhibited ETX-induced release of CGRP by 90% and 65% respectively. ETX-induced CGRP release was decreased under Ca2+-free perfusion by 80%. The data suggest that ETX directly trigger the release of CGRP from capsaicin-sensitive sensory nerve innervating blood vessels. The release of CGRP is dependent on extra-cellular Ca2+ and Ca2+-induced Ca2+ release from the intracellular Ca2+ store which is sensitive to ruthenium red.

Animals↗

PubMed1996

[Effects of inflammatory mediators on the release of CGRP from isolated mesenteric arterial bed of rat].

The purpose of the present study was to observe whether inflammatory mediators, such as: Prostaglandin E2 (PGE2), Bradykinin (BK), Histamine (HIS), Platelet active factor (PAF) and 5-hydroxytryptamine (5-HT), directly triggered the release of CGRP from perivascular nerves in isolated rat mesenteric arterial bed. The results showed that PGE2 (1-100 mumol/L) and BK (5-10 mumol/L) caused time- and concentration-dependent CGRP release, but HIS, PAF and 5-HT did not show significant effects. Our data indicate that PGE2 and BK are the major inflammatory mediators in triggering the release of CGRP from the perivascular CGRP-containing nerve.

Animals↗

PubMed1996

[The roles of nitric oxide and prostaglandins in the endotoxin-induced release of calcitonin gene-related peptide (CGRP) in rat mesenteric artery].

The mechanism of endotoxin (ETX) -induced release of CGRP was studied in isolated mesenteric arterial bed. ETX (50 micrograms/ml) caused a 16-fold increase of the release of CGRP. The effect of ETX was enhanced by L-arginine (L-Arg), a substratum of nitric oxide synthase (NOS), by 41%, but inhibited by NG-nitro-L-arginine (L-NNA), an selective inhibitor of NOS, L-NNA, and methylium blue (MB), an inhibitor of guanylate cyclase, respectively by 35% and 36%. These observations suggested that the effect of ETX is, at least partially, mediated by elevation of intracellular cGMP induced by NO. When endothelial cells were removed, the above responses of L-NNA and L-Arg still existed, indicating that ETX activated neuronal, rather than endothelial, NOS. Indomethacin and ibupofen, inhibitors of cyclooxygenase, also inhibited ETX-induced CGRP release by 34% and 39% respectively. When L-NNA and indomethacin were both incubated, no additive effects were discernible. The data suggest that ETX triggers CGRP release partially through activation of NOS located in perivascular sensory nerve and increase of NO, which is followed by activation of cyclooxygenase.

Animals↗

PubMed1995

Application of dot-immunogold-silver staining in the diagnosis of clonorchiasis.

All 35 confirmed clonorchiasis cases showed a positive reaction in dot-immunogold-silver staining (Dot-IGSS) with a mean serum titre of 1:1656, while none of the sera from 35 normal individuals reacted. A seroepidemiological survey of middle-school students revealed a positive rate of 17.0% (142/836), and 76.1% (105/138) of the serologically positive students were egg positive in stool examination. The egg positive rates in those with antibody at levels of 1+ to 4+ were 57.1% (28/49), 75.7% (28/37), 94.7% (36/38) and 92.9% (13/14) respectively. It is believed that Dot-IGSS can be used for the clinical diagnosis and epidemiological survey of clonorchiasis.

China↗

PubMed1995

[Effects of some physical and chemical factors on CGRP release from mesenteric arterial bed].

We have shown that calcitonin gene-related peptide (CGRP) is released into the circulation during endotoxin or hemorrhagic shock. In the present study, it was observed that low pH, elevated levels of lactic acid, hypertonic NaCl and hypertonic sucrose caused CGRP release from isolated mesenteric arterial bed (MAB) of rat. All the responses were blocked when MAB was pretreated with capsaicin. Ruthenium red, an inhibitor of Ca(2+)-induced Ca2+ release from intracellular Ca2+ pools, significantly inhibited the release of CGRP. In Ca2+ free medium, low pH, lactic acid and hypertonic solutions became no longer capable of inducing the release of CGRP. The above results suggest that the observed release of CGRP in MAB was mediated by capsaicin-sensitive sensory nerve endings, as a result of Ca(2+)-induced Ca2+ release from the intracellular Ca2+ store which is sensitive to ruthenium red.

Animals↗

PubMed1994

The population biology and control of Necator americanus in a village community in south-eastern China.

The population dynamic parameters of Necator americanus infections were estimated from longitudinal intensity and prevalence data from a village in south-eastern China. The theoretical predictions of a deterministic model incorporating these parameters were then compared with observed, horizontal, age-prevalence data from an infected population (N = 565), and an estimate of the basic reproduction rate (R0 = 3.7) of N. americanus was obtained. The findings indicate that populations of N. americanus might be easier to control by mass-treatment chemotherapy (eradication requiring only 63% of the population to be treated every year for 4 years) than those of Ascaris lumbricoides and Trichuris trichiura.

Adolescent↗

PubMed1994

Comparative study of Dot-immunogold silver staining and Dot-ELISA for the detection of serum antibodies against Wuchereria bancrofti.

Dot-immunogold silver staining (Dot-IGSS) and Dot-ELISA, using the soluble antigen of Brugia malayi, were employed to detect anti-Wuchereria bancrofti antibodies in 50 cases of Wuchereria bancrofti microfilaremia. The positive rates were 100% and 90% in Dot-IGSS and Dot-ELISA respectively. The average titer in the 45 positive cases was 1:184 (1:10-1:2560) for Dot-IGSS and 1:150 (1:10-1:2560) for Dot-ELISA, with 30 cases showing the same titer in both tests, 13 cases showing higher titer in Dot-IGSS than in Dot-ELISA and 2 cases in the former showing lower titers than in the latter. There was a linear relationship between the titers of antibodies detected by Dot-IGSS and by Dot-ELISA (r = 0.8443). Dot-IGSS, similar to Dot-ELISA, is easy to carry out and the result is easy to read. It is seen that Dot-IGSS is highly sensitive and specific and is practicable for immunodiagnosis and surveillance of filariasis.

Animals↗