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Biomedical subjects

Z X Wang

Publications and source records attributed to Z X Wang.

At least 19 recordsLinked to original sources
PubMed2006

[Epidemic situation analysis of Japanese encephalitis in 2005.].

BACKGROUND: To investigate the epidemic situation of Japanese encephalitis (JE) in three provinces, Guizhou, Sichuan, and Hubei in 2005. METHODS: Information about epidemic situation of JE, mosquitoes specimens were collected and titers of JE virus in hosts in the above three surveillance sites were determined. RESULTS: The reported cases of JE in Guizhou, Sichuan, and Hubei province accounted for 40.7% of total cases in 2005 in China. The numbers of cases in Guizhou and Sichuan ranked at the first two in China, morbidity exceeded 1/100,000, which was higher than average level in China. Zero to 10 years old children accounted for 90% in reported cases. Most of the cases were children lived at home. Almost all JE cases were presented from June to September, but most cases were reported between July and August. Investigaton of the density of vector showed that the dominant mosquitoes were Culex, especially the Culex tritaeniorhynchus. CONCLUSION: The epidemic status of JE was similar among the three provinces and the whole country. The number of JEV cases in Guizhou and Sichuan were the highest in China.

Animals↗
PubMed2005

Nematode biology and larval development of Thelazia callipaeda (Spirurida, Thelaziidae) in the drosophilid intermediate host in Europe and China.

Thelazia callipaeda, commonly known as the 'oriental eyeworm', has been recently reported in Italy and other European countries. The insect/s that act as intermediate hosts and details of larval development inside the vector remain unclear. In order to (1) demonstrate the species of fly that may act as vector/s for T. callipaeda in southern Italy (Site A) and China (Site B) and (2) describe the larval development of the nematode in the body of flies, 847 Phortica (Drosophilidae) flies were collected from the above two sites, each with a history of human and/or canine thelaziosis. Flies were identified as Phortica variegata (245 - site A) and Phortica okadai (602 - site B), experimentally infected by 1st-stage larvae (L1), kept at different temperatures and dissected daily until day 180 post-infection (p.i.). Dead flies from site A were subjected to specific polymerase chain reaction (PCR) assay to detect T. callipaeda. To demonstrate the role of Phortica as vectors of T. callipaeda, 3rd-stage larvae (L3) recovered from the proboscis of flies were deposited onto the cornea of the eyes of dogs and rabbits. Following dissection, 3 (2.9%) of P. variegata in site A were found to be infected by L3 in the proboscis on days +14, +21 and +53 p.i., compared with 26 (18.4%) of Phortica flies recorded as being positive by PCR. Sequences from positive PCR products were 99% identical to sequences of the corresponding species available in GenBank (AY207464). At site B, 106 (17.6%) of 602 dissected P. okadai were found to be infected by T. callipaeda larvae (different stages) and in total 62 L3 were recovered from the proboscis of 34 (5.6%) flies. The shortest time in which L3 were found was at day +14, +17, +19, and +50 p.i. respectively, depending on the environmental temperatures. Of 30 flies overwintered for 6 months, 6 L3 were detected at day +180 p.i. in 3 flies (10%). The biology of larval development was reconstructed on the basis of the dissection of 602 P. okadai-infected flies and the morphology of larval stages in the insect body described. The present work provides evidence that P. variegata and P. okadai act as vectors for T. callipaeda in southern Europe and in China, respectively. The phenomenon of overwintering is described here for the first time for T. callipaeda and discussed. Finally, the relationship between T. callipaeda and its fly vector is considered in light of disease prophylaxis and to model its dissemination into habitats and environments favourable to Phortica flies.

Animals↗
PubMed2005

Reduction of blood pressure with calcium and potassium supplementation in children with salt sensitivity: a 2-year double-blinded placebo-controlled trial.

An investigation of the reductive effect of blood pressure and increment of urinary sodium excretion with calcium and potassium supplementation in children with sodium sensitivity is conducted. In total of 261 school children who had completed a 2-year double-blinded, placebo-controlled trial with calcium and potassium supplementation salt sensitivity, with a salt volume expansion and contraction protocol, was determined. The results showed that in children with salt sensitivity, the increase in blood pressure in the supplementary group was lower by 4.3/4.8 mmHg than that in the placebo group (P<0.05), while no significant change was found between the supplementary group and placebo group in children with nonsalt sensitivity. With calcium and potassium supplementation, the night urinary sodium excretion in children with salt sensitivity was significantly increased (P<0.01), and it is negatively correlated with the increase in blood pressure. It was suggested that a moderate increase of calcium and potassium intake in children with salt sensitivity, through interaction with sodium, can promote urinary sodium excretion and may play contribute to the prevention of hypertension.

Blood Pressure↗
PubMed2005

Musca domestica is not a vector of Thelazia callipaeda in experimental or natural conditions.

Thelazia callipaeda Railliet and Henry (Spirurida: Thelaziidae), commonly called oriental eyeworm for its widespread presence in the Far East, has been recently found to affect dogs, cats and foxes in northern and southern Italy. Although the biology of T. callipaeda in the definitive hosts has been recently investigated, many doubts still remain about its biology in insect vectors. It has been suggested that more than one species of Diptera, namely Musca domestica Linnaeus (Diptera: Muscidae) and Amiota okadai Maca (Diptera: Drosophilidae), may be involved in the transmission of T. callipaeda in China. The aim of the work described here was to verify the role of M. domestica as a vector of T. callipaeda both in experimental and natural conditions. A total of 310 m. domestica (Group 1) were put in a cage and allowed to feed for 14 days around the eyes of a dog naturally infected by T. callipaeda. Ten flies were collected daily for 14 days. A total of 149 houseflies (Group 2) were fed with T. callipaeda first stage larvae (L1) and dissected at 1, 2 and 7 days post-infection. From June to August 2003, flies were netted (Group 3) in two different sites every 10 days both from the environment and directly from the periocular region of dogs affected by thelaziosis. Musca flies were examined for eyeworms by dissection and visual inspection of house flies (Groups 1 and 2) and using a molecular approach (Groups 1-3) via a specific amplification of the ribosomal internal transcribed spacer 1 (ITS1) sequence of T. callipaeda. On the whole, 180 pools of M. domestica flies were processed molecularly and all the experimentally infected flies (Groups 1 and 2) were found to be negative both at the visual dissection and at the molecular assay. Similarly, the 234 M. domestica collected from Group 3 were negative for T. callipaeda. The results clearly suggest that M. domestica is unlikely to act as a vector of T. callipaeda in southern Europe, in contrast with a single previous report.

Animals↗
PubMed2003

Nucleus accumbens oxytocin and dopamine interact to regulate pair bond formation in female prairie voles.

Although oxytocin (OT) and dopamine (DA) have been implicated in pair bond formation in monogamous prairie voles (Microtus ochrogaster), the nature of potential interactions between these two neurochemical systems and the brain circuits important for such interactions in the regulation of pair bonding have not been explored. Here, we demonstrated that access to both OT and DA D2-type receptors is necessary for pair bond formation, as blockade of either type of receptor prevented partner preferences induced by OT or a D2-type agonist. We also demonstrated that the nucleus accumbens (NAcc) is a brain area important for such OT-DA interactions. In NAcc, blockade of OT receptors prevented partner preferences induced by a D2-type agonist whereas blockade of D2-type, but not D1-type, DA receptors blocked OT-induced partner preferences. Together, our data suggest that concurrent activation of OT and DA D2-type receptors in NAcc is essential for pair bond formation in female prairie voles.

Animals↗
PubMed2001

Analysis of the origin of through-space proton NMR deshielding by selected organic functional groups.

GIAO-HF and IGLO-DFT computations of isotropic magnetic shieldings were used to map the NMR shielding environments of small molecules exemplifying selected organic functional groups. Two different probes were employed: a methane molecule and NICS (nucleus-independent chemical shifts) based on computed absolute isotropic shieldings. The reason for the different results obtained using these two probes is perturbation of the wave function by the proximity of methane to the pi bond, as analyzed by the localized orbital contributions to the shieldings. [structure: see text]

Journal Article↗
PubMed2001

Molecular anatomy of CCR5 engagement by physiologic and viral chemokines and HIV-1 envelope glycoproteins: differences in primary structural requirements for RANTES, MIP-1 alpha, and vMIP-II Binding.

Molecular analysis of CCR5, the cardinal coreceptor for HIV-1 infection, has implicated the N-terminal extracellular domain (N-ter) and regions vicinal to the second extracellular loop (ECL2) in this activity. It was shown that residues in the N-ter are necessary for binding of the physiologic ligands, RANTES (CCL5) and MIP-1 alpha (CCL3). vMIP-II, encoded by the Kaposi's sarcoma-associated herpesvirus, is a high affinity CCR5 antagonist, but lacks efficacy as a coreceptor inhibitor. Therefore, we compared the mechanism for engagement by vMIP-II of CCR5 to its interaction with physiologic ligands. RANTES, MIP-1 alpha, and vMIP-II bound CCR5 at high affinity, but demonstrated partial cross-competition. Characterization of 15 CCR5 alanine scanning mutants of charged extracellular amino acids revealed that alteration of acidic residues in the distal N-ter abrogated binding of RANTES, MIP-1 alpha, and vMIP-II. Whereas mutation of residues in ECL2 of CCR5 dramatically reduced the binding of RANTES and MIP-1 alpha and their ability to induce signaling, interaction with vMIP-II was not altered by any mutation in the exoloops of the receptor. Paradoxically, monoclonal antibodies to N-ter epitopes did not block chemokine binding, but those mapped to ECL2 were effective inhibitors. A CCR5 chimera with the distal N-ter residues of CXCR2 bound MIP-1 alpha and vMIP-II with an affinity similar to that of the wild-type receptor. Engagement of CCR5 by vMIP-II, but not RANTES or MIP-1 alpha blocked the binding of monoclonal antibodies to the receptor, providing additional evidence for a distinct mechanism for viral chemokine binding. Analysis of the coreceptor activity of randomly generated mouse-human CCR5 chimeras implicated residues in ECL2 between H173 and V197 in this function. RANTES, but not vMIP-II blocked CCR5 M-tropic coreceptor activity in the fusion assay. The insensitivity of vMIP-II binding to mutations in ECL2 provides a potential rationale to its inefficiency as an antagonist of CCR5 coreceptor activity. These findings suggest that the molecular anatomy of CCR5 binding plays a critical role in antagonism of coreceptor activity.

Alanine↗
PubMed2001

Identification and characterization of a novel human hepatocellular carcinoma-associated gene.

To investigate liver cancer-associated genes and to explore the molecular basis of liver cancer genesis, we have cloned a novel hepatocellular carcinoma (HCC)-related gene with a transcript of 2520 base pairs in length named HCCA2 by mRNA differential display polymerase chain reaction (DDPCR) and screening a placenta cDNA library. No significant homologous protein with known genes was found. Western blot analysis showed that HCCA2 could be expressed in transfected 293 cells. Northern hybridization analysis showed that HCCA2 mRNA was expressed in 79% (34/43) patients with HCC, most of whom had significantly high expression in HCC tissues, while not expressed in corresponding noncancerous liver tissues. The clinical pathological data showed that the HCCA2 was significantly associated with the invasion of tumour capsule (P = 0.0007) and the expression of ki-67 protein (P = 0.0022). Immunohistochemical staining confirmed that the HCCA2 protein was localized in cytoplasm of liver cancer tissues. According to amino acid analysis of the protein and its localization, it may play a role in a cascade of intracellular signal transduction because the protein was characterized with two Src homology 3 (SH3) binding-domains and several functional motifs of phosphorylation.

Adult↗
PubMed2001

Construction principles of "hyparenes": families of molecules with planar pentacoordinate carbons.

Density-functional theory calculations predict that three borocarbon units with planar pentacoordinate carbons -C3B3-, -C2B4-, and -CB5-, can replace the -(CH)3- subunits in aromatic or even in antiaromatic hydrocarbons to construct "hyparenes" (families of molecules with planar pentacoordinate carbons). These borocarbon units contribute two, one, and zero electrons, respectively, to the parent pi system. Depending on the choice of these units, the hyparenes (judging from computed proton and nucleus-independent chemical shifts), can maintain or can interconvert the aromatic or antiaromatic character of the parent compounds. The hyparenes are low-lying local minima with normal carbon-boron, boron-boron, and carbon-carbon bond lengths. The multicenter bonding in the hyparenes involves contributions of partial sigma and partial pi bonds to the planar pentacoordinate carbons; the octet rule is not violated. Borocarbon species, for which there is some mass spectrometric evidence, might be observed and identified, for example, in matrix isolation by vibrational spectroscopy.

Journal Article↗
PubMed2001

(E)-1-(2'-deoxy-beta-D-ribofuranosyl)-2,4-difluoro-5-(2-iodovinyl)benzene.

This analysis of the title compound, C13H13F2IO3, establishes the orientation of (E)-5-(CH=CH-I) as antiperiplanar (ap) to the C-C bond (5-6 position) of the 2,4-difluorophenyl ring system, with the (E)-5-(CH=CH-I) H atom located in close proximity (2.17 A) to the F4 atom of the 2,4-difluorophenyl moiety.

Antiviral Agents↗
PubMed2001

A theoretical prediction of potentially observable lithium compounds with planar tetracoordinate carbons.

Several potentially experimentally accessible lithiated heterocyclic and heteroatom compounds with planar tetracoordinate carbons (ptC) have been predicted computationally. These utilize the strong electron-donating ability and the bridging proclivity of lithium to achieve the ptC preferences. As the p orbitals on the central carbons are only partially occupied, their electronic structures are similar to those of the related carbenes, e.g. imidazole-2-ylidene, rather than to the other ptC compounds such as dilithiocyclopropane.

Journal Article↗
PubMed2001

Effects of leukaemia inhibitory factor on endometrial receptivity and its hormonal regulation in rabbits.

The effects of hormones on production of leukaemia inhibitory factor (LIF) and the uterine receptivity in rabbits were studied. In ovariectomised rabbits, LIF protein was not detected in control but upregulated by progesterone alone. Oestrogen had a slightly negative effect when the rabbits were treated with both oestrogen and progesterone. Mifepristone (Mi) inhibited the progesterone-stimulated production of LIF in rabbit uterus. The transfer of embryos to LIF-treated recipients significantly increased pregnancy rate (70%) and implantation rate (27%) as compared with control (pregnancy rate=40% and implantation rate=17%). The transfer of embryos to LIF and mifepristone-treated recipients significantly decreased pregnancy rate (30%) and implantation rate (9%). The results indicated that LIF protein had a beneficial effect on uterine receptivity and mifepristone prevented this effect.

Animal Population Groups↗