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Biomedical subjects

Y Zhong

Publications and source records attributed to Y Zhong.

At least 19 recordsLinked to original sources
PubMed2006

Study of metabolites from the degradation of polycyclic aromatic hydrocarbons (PAHs) by bacterial consortium enriched from mangrove sediments.

The PAH metabolites produced during degradation of fluorene, phenanthrene and pyrene by a bacterial consortium enriched from mangrove sediments were analyzed using the on-fiber silylation solid-phase microextraction (SPME) combining with gas chromatography-mass spectrometry (GC-MS) method. Seventeen metabolites at trace levels were identified in different PAH degradation cultures based on the full scan mass spectra. In fluorene degradation cultures, 1-, 2-, 3- and 9-hydroxyfluorene, fluorenone, and phthalic acid were detected. In phenanthrene and pyrene degradation cultures, various common metabolites such as phenanthrene and pyrene dihydrodiols, mono-hydroxy phenanthrene, dihydroxy pyrene, lactone and 4-hydroxyphenanthrene, methyl ester, and phthalic acid were found. The detection of various common and novel metabolites demonstrates that SPME combining with GC-MS is a quick and convenient method for identification as well as monitoring the real time changes of metabolite concentrations throughout the degradation processes. The knowledge of PAH metabolic pathways and kinetics within indigenous bacterial consortium enriched from mangrove sediments contributes to enhance the bioremediation efficiency of PAH in real environment.

Bacteria↗
PubMed2006

Three-dimensional direct writing of B35 neuronal cells.

We have demonstrated two-dimensional and three-dimensional transfer of B35 neuronal cells onto and within polymerized Matrigel substrates, using matrix-assisted pulsed laser evaporation-direct write (MDW). The B35 cells were transferred from a quartz ribbon to depths of up to 75 microm by systematically varying the fluence emitted from the ArF (lambda = 193 nm) laser source. MDW-transferred cells were examined using terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL), 4',6-diamidino-2-phenylindole (DAPI), and alpha-tubulin staining. Confocal microscopy has shown that the transferred B35 cells extended their axons outward in three dimensions within the polymerized Matrigel substrate. The B35 cells made axonal connections and formed a three-dimensional neural network within 72 h after MDW transfer. In addition, TUNEL staining demonstrated that only 3% of the B35 cells underwent apoptosis after being transferred using the MDW process. MDW and other emergent direct write processes may provide unique approaches for creating layered, heterogeneous, three-dimensional cell-seeded scaffolds for use in peripheral nerve repair.

Animals↗
PubMed2006

Endoscopic mucosal resection of early esophageal squamous cell cancer using the Duette mucosectomy kit.

BACKGROUND AND STUDY AIM: Endoscopic mucosal resection (EMR) is a less invasive alternative treatment strategy to surgery for intramucosal esophageal squamous cell carcinoma (SCC). This study described our initial experience with the newly introduced Duette Multiband Mucosectomy Kit (Cook Ireland Ltd, Limerick, Ireland) for the treatment of extensive early esophageal SCC. PATIENTS AND METHODS: Five patients with extensive early esophageal SCC, covering at least half of the circumference of the esophageal wall and measuring a mean of 2.8 cm longitudinally, underwent EMR after EUS staging. RESULTS: EMR was successfully completed in one session in five patients. Post-EMR stricture occurred in four patients but was successfully treated with bougienage. One patient did not return for follow-up after bougienage and died from ischemic heart disease 3 months later. For the remaining four patients, there was no recurrence over a mean follow up of 14.7 months. CONCLUSION: This new device obviates the need for repeated insertion of the endoscope during the process of ligation and resection and thus facilitates EMR of extensive SCC.

Aged↗
PubMed2006

Primary precutting versus conventional over-the-wire sphincterotomy for bile duct access: a prospective randomized study.

BACKGROUND AND STUDY AIMS: Precut is a well-known technique that is used if repeated attempts at common bile duct (CBD) cannulation fail. Opinions on the complication rate of precut are conflicting, however. The aim of the present study was to compare the efficacy and complication rate of precut used as a primary method of CBD access with the efficacy and safety of the conventional technique. PATIENTS AND METHODS: During the 19-month study period, consecutive patients who were scheduled for first-time endoscopic sphincterotomy (ES) for a variety of biliary disorders were randomized into two groups: patients in group A underwent conventional wire-guided biliary cannulation followed by ES (with precut being performed only when this failed); in patients in group B precut was used as a primary technique to gain biliary access, followed by wire-guided ES. We used a specially designed, modified Erlangen type of sphincterotome for precutting. RESULTS: A total of 291 patients (100 men, 191 women; mean +/- SD age 65 +/- 17.5 years) were recruited: 146 patients were assigned to group A (conventional approach) and 145 to group B (primary precut approach). The indications for ES were comparable in the two groups. In group A, wire-guided cannulation of the CBD failed in 42 patients. Secondary precut was successful in 41 of these patients, leading to an overall success rate of 99.3 %. In group B, the ES success rate using primary precut was 100 % at the first attempt. The mean time to successful deep CBD cannulation was 8.3 +/- 2.1 minutes in group A and 6.9 +/- 1.8 minutes in group B ( P < 0.001). The incidence of mild to moderate pancreatitis was similar in the two groups (2.9 % in group A vs. 2.1 % in group B, P > 0.05). Mild bleeding occurred in only one patient (from group A) and this was controlled by epinephrine injection. None of the study patients developed severe pancreatitis or perforation. CONCLUSIONS: In experienced hands, an approach using primary precut appears to be at least as successful and safe as a conventional approach using guide-wire-based CBD cannulation followed by ES, and might also be a quicker method.

Adolescent↗
PubMed2006

Identification of Vibrio harveyi using PCR amplification of the toxR gene.

AIMS: The aim of this study was to develop an effective method for the identification of Vibrio harveyi based on using the toxR gene as a taxonomic marker. METHODS AND RESULTS: Primers for the toxR gene were designed for specificity to V. harveyi, and incorporated in a polymerase chain reaction (PCR). The results of the PCR, which took <5 h from DNA extraction to amplification, revealed positive amplification of the toxR gene fragment in 20 V. harveyi isolates including type strains, whereas DNA from 23 other Vibrionaceae type strains and 13 Vibrio parahaemolyticus strains were negative. The detection limit of the PCR was 4.0 x 10(3) cells ml(-1). In addition, the technique enabled the recognition of V. harveyi from diseased fish. CONCLUSIONS: The PCR was specific and sensitive, enabling the identification of V. harveyi within 5 h. SIGNIFICANCE AND IMPACT OF THE STUDY: The PCR allowed the rapid and sensitive detection of V. harveyi.

Animals↗
PubMed2006

Separation of heart rate variability components of the autonomic nervous system by utilizing principal dynamic modes.

This work introduces a modified Principal Dynamic Modes (PDM) methodology using eigenvalue/eigenvector analysis to separate individual components of the sympathetic and parasympathetic nervous contributions to heart rate variability. We have modified the PDM technique to be used with even a single output signal of heart rate variability data, whereas the original PDMs required both input and output data. This method specifically accounts for the inherent nonlinear dynamics of heart rate control, which the current method of power spectrum density (PSD) is unable to do. Propranolol and atropine were administered to normal human volunteers intravenously to inhibit the sympathetic and parasympathetic activities, respectively. With separate applications of the respective drugs, we found a significant decrease in the amplitude of the waveforms that correspond to each nervous activity. Furthermore, we observed near complete elimination of these dynamics when both drugs were given to the subjects. Comparison of our method to the conventional low/high frequency ratio of PSD shows that PDM methodology provides much more accurate assessment of the autonomic nervous balance by separation of individual components of the autonomic nervous activities. The PDM methodology is expected to have an added benefit that diagnosis and prognostication of a patient's health can be determined simply via a non-invasive electrocardiogram.

Adult↗
PubMed2005

Cadmium contamination in orchard soils and fruit trees and its potential health risk in Guangzhou, China.

This study examines cadmium (Cd) contamination in orchard soils and fruit trees in Guangzhou, China, and assesses its potential health risk. Soils and tissues samples of three species of fruit trees were collected from three orchards. The average soil Cd concentration was 1.27, 1.84 and 0.68 mg/kg in orchards I, II, and III, respectively. The carambola (Averrhoa carambola) accumulated exceptionally high concentrations of Cd (7.57, 10.84, 9.01 and 2.15 mg/kg dw in root, twig, leaf and fruit, respectively), being 6.0-24 times and 4.0-10 times the corresponding tissue Cd in the longan (Dimocarpus longan) and wampee (Clausena lansium), respectively. Furthermore, all Cd concentrations (0.04-0.25 mg Cd/kg fw) of the fruits exceeded the tolerance limit of cadmium in foods of PR China (0.03 mg/kg fw). Our results indicate that the carambola tree has high Cd accumulation capacity and might be a Cd accumulator; and its fruit, among the three species of fruits studied, also poses the highest potential health risk to local residents.

Agriculture↗
PubMed2003

Bladder and cutaneous sensory neurons of the rat express different functional P2X receptors.

The expression and functional responses of P2X receptors in bladder and cutaneous sensory neurons of adult rats and mice have been studied using immunohistochemistry and patch clamp techniques. Cell bodies of bladder pelvic afferents were identified in L6 and S1 dorsal root ganglia (DRG), following Fast Blue injection into the muscle wall of the urinary bladder. Similarly, cutaneous sensory neurons were identified in L3 and L4 DRG, following Fast Blue injection into the saphenous nerve innervating the skin. Bladder sensory neurons contained only weak to moderate P2X(3)-immunoreactivity (IR), in contrast to strong P2X(3)-IR observed in a sub-population of cutaneous afferents. Whole-cell patch-clamp recordings revealed that approximately 90% of bladder afferent neurons responded to alpha beta-methylene ATP (alpha beta meATP) and ATP (30 microM) with persistent currents, which were inhibited by 2',3'-O-trinitrophenyl-ATP (TNP-ATP) (0.3 microM) to 6.4+/-1.9% and 8.0+/-2.6% of control, respectively (n=8). The remaining bladder sensory neurons demonstrated biphasic, transient or no response to P2X agonists. In contrast, only 24% of cutaneous afferent neurons gave persistent currents to alpha beta meATP (30 microM), with 66% of cells giving transient or biphasic currents and the remaining 10% being non-responsive. Our results suggest that, in contrast to DRG neurons in general, bladder sensory neurons projecting via pelvic nerves express predominantly P2X(2/3) heteromeric receptors, which are likely to mediate the important roles of ATP as a signaling molecule of urinary bladder filling and nociception.

Adenosine Triphosphate↗
PubMed2003

Lactose intolerance: analysis of underlying factors.

BACKGROUND: We studied the degree of lactose digestion and orocecal transit time (OCTT) as possible causes for the variability of symptoms of lactose intolerance (LI) in a sample of a population with genetically determined low lactase activity. METHODS: Lactose digestion index (LDI) was measured by the recently developed 13C-lactose/2H-glucose test. The OCTT was determined using the breath hydrogen test. Based on a 6-h symptom score (SSC) after a challenge dose of 25 g of lactose the subjects were divided into a tolerant group (T: n= 15; SSC = 0) and an intolerant group (IT: n= 28; SSC 1-40). The intolerant group was subdivided according to the severity of symptoms: group ITa (n = 17; mild symptoms without diarrhoea) and group ITb (n = 11; with diarrhoea). RESULTS: The LDI was lower in the intolerant group (0.34 +/- 0.14) (mean +/- SD) than in the tolerant group (0.47 +/- 0.14) (P = 0.008). The OCTT of group IT (60, 30-90 min) (median, quartiles) was significantly shorter than that of group T (105, 60-120 min) (P = 0.003) and was positively correlated with the LDI (P = 0.050). In groups ITa and ITb the OCTT (60, 30-90 min; 60, 26-83 min) and LDI (0.30 +/- 0.14; 0.39 +/- 0.14) were similar. CONCLUSIONS: Lactose digestion capacity, which is determined by small intestinal lactase activity as well as by OCTT, affects the occurrence of lactose intolerance. However, the major difference in intolerance symptoms is caused by differences in the colonic processing of maldigested lactose.

Adult↗
PubMed2003

Validation of a modified PCR-based method for identifying mutant restricted ovulator chickens: substantiation of genotypic classification by phenotypic traits.

Upon photostimulation, restricted ovulator (RO) female chickens exhibit endogenous hyperlipidemia, develop atherosclerotic lesions, and generally fail to lay eggs. This phenotype results from a point mutation in the gene specifying the very low density lipoprotein receptor (VLDLR), whose protein product normally mediates the massive oocytic uptake of egg yolk precursors from the circulation. Taking advantage of the single base change in the mutant VLDLR allele, a PCR-based method for the rapid identification of RO chickens was developed at the Biocenter and University of Vienna, Austria. However, this procedure was incompletely validated because phenotypic data were not obtained and conventional progeny testing of sons and grandsons was not performed. Here, the assay validation was completed by providing plasma lipid concentrations, plasma very low density lipoprotein particle sizes, or egg production records of PCR-genotyped females and their brothers and sires to demonstrate that each bird's phenotypic traits substantiated their genotypic classification. Moreover, several methodological modifications resulted in improved chemical safety, speed, and cost of preparing and analyzing genomic DNA from chicken erythrocytes. Because the ovaries of mutant RO females generally contain numerous vitellogenic follicles in the absence of a functional oocyte plasma membrane VLDLR, the existence of an alternate system for the oocytic uptake of plasma very low density lipoprotein and vitellogenin is suggested, whereas a physiological explanation as to why some, but not all, mutant RO hens are able to ovulate and lay eggs is lacking.

Animals↗
PubMed2002

Assessment of reproductive function in mutant restricted ovulator carrier roosters.

Two splice variant forms of the chicken very low density lipoprotein receptor (VLDLR) have recently been shown to exist in both male and female chicken gonads. The longer form, containing an O-linked sugar domain, is produced in the somatic cells of the testes and ovaries, whereas the shorter form, which lacks this domain, is expressed in the male and female germ cells. The latter is essential for female reproduction, because a naturally occurring point mutation in the gene encoding the short form of the VLDLR causes its functional absence, resulting in atherosclerosis and a general failure to lay eggs. Thus, the term restricted ovulator (RO) was originally coined to describe females with the mutant gene. In contrast, the roles of the VLDLR gene products in male reproduction have yet to be defined, because only heterozygous RO roosters, which have a mutant allele of the VLDLR gene (short form) on one of their two Z (sex) chromosomes, can be obtained. However, the question of whether two normal alleles of the VLDLR gene are needed for optimal male reproductive performance can be addressed. Here, the reproductive abilities of heterozygous RO roosters were compared to their wild-type siblings. The RO roosters were found to be phenotypically normal, suggesting that only one normal allele for the VLDLR gene is needed for optimal male reproductive performance. Alternately, it is also possible that the one normal allele compensated for the presence of the mutant one in terms of VLDLR gene product production (i.e., a dosage compensation).

Alternative Splicing↗
PubMed2002

A DNA vaccine encoding a cell-surface protein antigen of Streptococcus mutans protects gnotobiotic rats from caries.

A cell-surface protein antigen (PAc) of Streptococcus mutans is considered a virulence factor because it may mediate initial attachment of Streptococcus mutans to tooth surfaces. Thus, inhibiting PAc is predicted to provide protection against caries. To develop vaccines against dental caries, we constructed a DNA vaccine, pCIA-P, which encodes two high-conservative regions of PAc. Expression of the recombinant protein was obtained in eukaryotic cells in vitro and in vivo. In this report, we provide evidence that fewer caries lesions, and high levels of PAc-specific salivary IgA antibody and serum IgG antibody, were observed in gnotobiotic rats following targeted salivary gland (TSG) administration of pCIA-P. This study shows that the recombinant DNA vaccine pCIA-P could induce protective anti-caries immune responses and that TSG immunization is a promising strategy for the inhibition of dental caries.

Analysis of Variance↗
PubMed2001

Rapid activation of ERK1/2 mitogen-activated protein kinase by corticosterone in PC12 cells.

Although the nongenomic effects of glucocorticoids have been well acknowledged, its precise intracellular signal transduction pathway remains to be elucidated. The present study using Western immunoblot and protein kinase activity assay, for the first time, showed that corticosterone (B) can induce a rapid activation of Erk1/2 mitogen-activated protein kinase (MAPK) in PC12 cells. The dose-response curve was bell shaped, with the maximal activation at 10(-9) M in 15 min. The results from immunofluorescence staining also revealed that the activated Erk1/2 MAPK was translocated from cytoplasm to nucleus of PC12 cells in 15 min. Activation of Erk1/2 MAPK by B was apparently not mediated by the classical cytosolic steroid receptors, for B-BSA can induce the phosphorylation of Erk1/2 MAPK, but the antagonist (RU38486) cannot block the phosphorylation of Erk1/2 MAPK induced by B. Phosphorylation of Erk1/2 MAPK induced by B was not affected by a tyrosine kinase inhibitor (genistein), suggesting that the pathway did not involve the tyrosine kinase activity. On the other hand, protein kinase C activator (PMA) can activate and protein kinase C inhibitor (Gö6976) can block the activation of Erk1/2 MAPK induced by B. Taken together, these data clearly demonstrated that B might act via putative membrane receptor and rapidly activate Erk1/2 MAPK through protein kinase C alpha in PC12 cells.

Active Transport, Cell Nucleus↗
PubMed2001

Corticosterone-induced rapid phosphorylation of p38 and JNK mitogen-activated protein kinases in PC12 cells.

The present study showed that corticosterone (B) could induce a rapid activation of p38 and c-Jun NH(2)-terminal protein kinase (JNK) in PC12 cells. The dose-response and time-response curves were bell-shaped with maximal activation at 10(-9) M and at 15 min. RU38486 had no effect, and bovine serum albumin-coupled B could induce the activation. Genistein failed to block the phosphorylation, suggesting the pathway was not involved in tyrosine kinase activity. Phorbol 12-myristate 13-acetate could mimic, while Gö6976 could abolish the actions. These results demonstrated that B might act via a putative membrane receptor to activate p38 and JNK rapidly through a protein kinase C-dependent pathway.

Animals↗
PubMed2001

Characterization of polyethylene glycol-modified proteins by semi-aqueous capillary electrophoresis.

A new program to characterize polyethylene glycol-modified (PEGylated) proteins is outlined using capillary zone electrophoresis (CZE). PEGylated ribonuclease A and lysozyme were selected as examples. Five separation procedures were compared to select out the mixed buffer of acetonitrile-water (1:1, v/v) at pH 2.5 as the best to characterize the PEGylated proteins without sample pretreatment. Polyethylene oxide (PEO) with a high molecular mass of 8 x 10(6) was applied to rinse the capillary to form a dynamic coating which would decrease the undesirable proteins adsorbed to the inner wall of the silica. The electroosmotic flow (EOF) mobility of the five procedures was determined, respectively. It is found that acetonitrile is mainly responsible for the good resolution of PEGylated proteins with the help of PEO coating in the semi-aqueous system. The low EOF mobility and current in the semi-aqueous system might also have some responsibility for the high resolution. The semi-aqueous procedure described in this paper also demonstrates higher resolution of natural proteins than aqueous ones.

Electrophoresis, Capillary↗
PubMed2001

Effect of human oviductal epithelial cell cultural medium on cryopreserved human sperm survival.

The human oviduct is known as a functional site for gamete transportation, retention, fertilization and zygote development. Previous studies have shown that human oviductal epithelial cell cultural medium (OECCM) has a positive effect on prolongation of sperm motility for some cryopreserved human sperm without cryodamage. However, for most cryopreserved sperm, OECCM could not improve their survival prolongation. In this study, we assessed the influence of human OECCM on the motility longevity of cryopreserved human sperm with an in vitro incubation method.

Cell Survival↗