Biomedical subjects

Z Jiang

Publications and source records attributed to Z Jiang.

At least 91 records · Page 5Linked to original sources

PubMed2001

[The study of countermeasures on measles control in infants].

OBJECTIVE: To understand: a) measles antibody levels in purpura and their newborns, and the relation between them, b) maternal transferred measles antibody level of different age group infants, c) immunization rates of success in 6 and 8 month old infants, d) to study measles control countermeasures on infants. METHOD: To test measles IgG antibody levels of infant's blood using ELISA method. RESULTS: Antibody levels of measles in 58 pairs of mother and their newborns, 51 pairs were the same, while 7 pairs were different. Measles antibody levels in newborns was not high and reduced to 50% in 3 months, 20% in 6 months, and 15% in 8 months. The antibody levels in 6 and 8 month olds were low, nearly no protection to children. It was found that rates of immunization success and the antibody distribution were not statistically different between 6 and 8 months olds after measles vaccination. CONCLUSION: It was found that the measles antibody level in most matured women was low. Since mother's measles antibody level has close relation to their newborns, it seems that the newborn's antibody level can be improved by vaccination to matured women. In order to reduce morbidity of infant measles, the age of first vaccination of measles vaccine should be changed from 8 months old to 6 months old in some regions.

Age Factors↗

PubMed2001

[Pathomorphologic features of clinical stage A prostate carcinoma and causes for misdiagnosis and missed diagnosis].

OBJECTIVE: To study the pathomorphologic features and causes for misdiagnosis and missed diagnosis of clinical stage A prostate carcinoma. METHODS: Prostate samples from a series of 1 020 prostate resections performed in five Shanghai hospitals were obtained, from which 50 clinical stage A carcinoma were studied by immunohistochemistry, according to tumor differentiation and their volume, they were divided into stage A1 and A2 disease. The pathomorphologic features of stage A1 and A2 disease were compared, and the causes for misdiagnosis were analysed. RESULTS: Stage A1 cancer were well- or moderately well-differentiated, of low volume and tended to be multifocal; Stage A2 cancers were poorly differentiated, of high volume, diffuse infiltration and with high grade prostatic intraepithelial neoplasia. 8 cases were misdiagnosed of which 7 cases were stage A1 and misdiagnosed as benign proliferous small gland lesions and 1 case of A2 disease was misdiagnosed as epithelioid histiocytic reactive proliferation. CONCLUSIONS: Stage A1 cancer tended to be initiated in the transition zone and the central zone of the hyperplastic prostate. Stage A2 cancers were mostly middle grade to high grade cancers initiated in the peripheral region and then invaded the central area. The lower incidence of stage A carcinoma in China is related to the small amount of biopsy tissue, careless microscopic observation, or lack of the ability to diagnose stage A1 cancer.

Aged↗

PubMed2001

[Study on the working noise in BYPC and the effects caused by working noise on the workers' vestibular and auditory function].

OBJECTIVE: In order to observe the kinds and intensity of the working noise of Yansan Petrochemical Co. and the effects caused by the working noise on the workers' vestibular and auditory function. METHOD: The intensity and frequency of the working noise were recorded by exactolnoisemeter in the workshop. One hundred and seventeen workers were tested in routine pure-tone tested method. The SPVN and ABR were tested within fifty-one workers of all. RESULT: The working noise of Yansan Petrochemical Co. belongs to the broad band and steady noise. The intensity of the working noise were during 85.7-104.0 dB(A) and the main frequency were during 1-8 kHz. About 59 percent workers who exposed to the working noise had hearing loss. The most hearing-loss were in the high frequency. The hearing-loss of speech frequency were slight. Workers who have more six years standing have obviously increased hearing-loss than the workers who have less five years standing. There were significant differences the ABR thresholds and wave-interval between the tested and controlled groups. The SPVN and CP were abnormal in more than 17.4 percent workers with hearing loss. CONCLUSION: The working noise of Yansan Petrochemical Co. belongs to the broad band and steady noise. Working noise can lead to workers' hearing loss of certain degrees who exposed in the noise for a long time. Obvious correlation was not defined between the hearing-loss and the abnormal vestibular response group.

Adult↗

PubMed2000

E2F1 and p53 are dispensable, whereas p21(Waf1/Cip1) cooperates with Rb to restrict endoreduplication and apoptosis during skeletal myogenesis.

We describe temporal and genetic analyses of partially rescued Rb mutant fetuses, mgRb:Rb-/-, that survive to birth and reveal specific defects in skeletal muscle differentiation. We show that in the absence of Rb, these fetuses exhibit increased apoptosis, bona fide endoreduplication, and incomplete differentiation throughout terminal myogenesis. These defects were further augmented in composite mutant fetuses, mgRb:Rb-/-:p21-/-, lacking both Rb and the cyclin-dependent kinase inhibitor p21(Waf1/Cip1). Although E2F1 and p53 mediate ectopic DNA synthesis and cell death in several tissues in Rb mutant embryos, both endoreduplication and apoptosis persisted in mgRb:Rb-/-:E2F1-/- and mgRb:Rb-/-:p53-/- compound mutant muscles. Thus, combined inactivation of Rb and p21(Waf1/Cip1) augments endoreduplication and apoptosis, whereas E2F1 and p53 are dispensable during aberrant myogenesis in Rb-deficient fetuses.

Animals↗

PubMed2000

Unique biochemical, cytotoxic, and antitumor activity of camptothecin and 4beta-amino-4'-O-demethylepipodophyllotoxin conjugates.

Two compounds having a camptothecin (CPT) analog conjugated to the 4beta-amino-4'-O-demethylepipodophyllotoxin analog were evaluated for their biochemical and biological activities. W1[camptothecin-(para)-4beta-amino-4'-O-demethylepipodophyllotoxin] had no activity against topoisomerase II (TOP II), but inhibited topoisomerase I (TOP I) with an IC(50) value 2-fold higher than CPT. W2 [camptothecin-(ortho)-4beta-amino-4'-O-demethylepipodophyllotoxin] had inhibitory activity against TOP I and TOP II with IC(50) values 1.5-fold higher than either CPT or etoposide (VP-16). Both conjugates had similar cytotoxicity against the KB cell line, although the protein-linked DNA breaks (PLDBs) generated by W2 in KB cells were about 4-fold more than those of W1. No cross-resistance with the two conjugates was seen in a VP-16-resistant KB subline, which showed down-regulation of TOP II and overexpression of the multiple drug resistance-associated protein, or in a vincristine-resistant KB subline with overexpression of gp-170/mdr-1. The CPT-resistant KB variant (KB CPT 100), which has a reduction in TOP I content and another mechanism that occurs post-PLDB formation, was partially resistant to both compounds. W1 was not affected by this post-PLDB resistance mechanism. Cell cycle analysis demonstrated that W1 and W1 had similar cell cycle effects on KB and KB CPT 100 cells, which accumulated in S-phase upon drug treatment. These results suggested that W1 and W2 exerted their cytotoxicity through TOP I. In CPT-resistant cells, however, an unidentified target also may be involved in the cytotoxic action of W1 and TOP II may still be a target for W1. In vivo, W1 was more effective against the growth of human prostate cancer cells in nude mice than VP-16, CPT, or W2. Given its antitumor activity and unique biochemical mechanism of action, W1 warrants exploration as an antitumor compound.

Animals↗

PubMed2000

Characteristics of intestinal absorption and disposition of glycyrrhizin in mice.

As basic studies to apply an intestinal pressure-controlled colon delivery capsule (PCDC) for glycyrrhizin (GZ), the characteristics of intestinal absorption and disposition of GZ were investigated in mice. In the in vivo study, after intravenous (iv) administration of GZ, 10 mg/kg dose, plasma GZ disappeared from the systemic circulation with t(1/2(alpha)) of 0.0063 h, thereafter, it slowly declined with t(1/2(beta)) of 15.23 h. The area under the plasma drug concentration versus time curve (AUC) values of iv (10 mg/kg), intracolonic (50 mg/kg) and intraduodenum (50 mg/kg) administrations were 115.1, 16.7 and 2.7 microgh/mL, respectively. The AUC values of plasma glycyrrhetic acid (GA), a degradation product after intracolonic and intraduodenum administrations were 2.8 and 8.4 microgh/mL, respectively. In the in situ closed loop study, the concentrations of GZ in plasma and liver after intracolonic administration were significantly increased (p<0.05) in comparison with those after intrajejunum or intraileum administration, while the concentration of GA in plasma and liver after intracolonic administration had trends to increase. These observations clearly suggest that the intracolonic administration is a useful way to improve the oral bioavailability of GZ and to enhance its pharmacological efficacy. These pharmacokinetic results of GZ suggest that GZ is a subject drug to be applied for the PCDC system we previously developed. The PCDCs formulation of GZ will enable us to carry GZ to the colon and enhance the oral bioavailability of GZ.

Animals↗

PubMed2000

Ceramides induce apoptosis in HeLa cells and enhance cytochrome c-induced apoptosis in Xenopus egg extracts.

Ceramide has been reported to induce typical apoptotic changes in nuclei incubated in a cell-free system, and that the addition of ceramide bypasses the requirement for mitochondria. Here, we explore the possible pathways by which ceramide induces apoptosis either in intact cells or in a cell-free system which we have developed. We found that in the cell-free system, C2-ceramide is not able to induce apoptosis in nuclei whereas cytochrome c does, but it is able to induce HeLa cells to undergo apoptosis. Ceramide is also not able to induce apoptosis when added into the cell-free system together with purified mitochondria. Further investigation showed that C2-ceramide at certain concentrations greatly increases nuclear apoptosis caused by cytochrome c in the cell-free system. From these results we conclude that the induction of apoptosis by ceramide may require intact cells in which some unknown signal transduction pathways are involved.

Animals↗

PubMed2000

Study of the adsorption behavior of heavy metal ions on nanometer-size titanium dioxide with ICP-AES.

A new method using nanoparticle TiO2 as solid-phase extractant coupled with ICP-AES was proposed for simultaneous determination of trace elements. The adsorption behavior of nanometer TiO2 towards Cu, Cr, Mn and Ni was investigated by ICP-AES, and the adsorption pH curves, adsorption isotherms and adsorption capacities were obtained. It was found that the adsorption rates of the metal ions studied were more than 90% in pH 8.0-9.0, and 2.0 mol L-1 HCl was sufficient for complete elution. Nanometer TiO2 possesses a significant capacity for the sorption of the metal ions studied which is higher than the capacity of silica, the commonly used extractant. The method has been applied to the analysis of some environmental samples with satisfactory results.

Journal Article↗

PubMed2000

Comparative mapping between humans and pigs: localization of 58 anchorage markers (TOASTs) by use of porcine somatic cell and radiation hybrid panels.

To increase the number of Type I markers that are directly informative for comparative mapping, 58 anchorage markers, TOASTs (Traced Orthologous Amplified Sequence Tags), were mapped in pig. With specific consensus primers, 76 TOASTs were tested in pig: 50 were regionally localized in pig on a somatic cell hybrid panel (SCHP), and 51 were mapped on the whole genome, INRA/University of Minnesota porcine Radiation Hybrid panel (IMpRH). Comparison of marker positions on RH and cytogenetic maps indicated general concordance except for two chromosomal regions. For RH mapping, all markers, apart from one, were significantly linked (LOD > 4.8) to a marker of the first-generation radiation hybrid map. Localization of new markers on the initial map is necessary for drawing a framework map as shown for Chromosome Sscr 14. The addition of four TOASTs has enabled us to propose an improved map, using a threshold likelihood ratio of 1000/1. At the whole-genome level, this work significantly increased (by 50%) the number of precisely mapped genes on the porcine RH map and confirmed that the IMpRH panel is a valuable tool for high-resolution gene mapping in pig. Porcine PCR products were sequenced and compared with human sequences to verify their identity. Most of the localizations made it possible to either confirm or refine the previous comparative data between humans and pigs obtained through heterologous chromosomal painting or gene mapping. Moreover, the use of TOASTs in mapping studies appears to be a complement to other strategies using CATS, human ESTs, or heterologous FISH with BACs which had already been applied to improve the gene density of comparative genomic maps for mammals.

Animals↗

PubMed2000

Genetic modulation of tumor antigen presentation.

An effective cancer-cell vaccine is created by expressing major-histocompatibility-complex (MHC) class II molecules without the invariant chain protein (Ii) that normally blocks the antigenic-peptide-binding site of MHC class II molecules at their synthesis in the endoplasmic reticulum. Such tumor-cell constructs are created either by the transfer of genes for MHC class IIalpha and beta chains, or by the induction of MHC class II molecules and Ii protein with a transacting factor, followed by Ii suppression using antisense methods. Preclinical validation of this approach is reviewed with the goal of using this immunotherapy for metastatic human cancers.

Animals↗

PubMed2000

In vitro validation of volumetric blood flow measurement using Doppler flow wire.

Determination of any volumetric blood flow requires assessment of mean blood flow velocity and vessel cross-sectional area. For evaluation of coronary blood flow and flow reserve, however, assessment of average peak velocity alone is widely used, but changes in velocity profile and vessel area are not taken into account. We studied the feasibility of a new method for calculation of volumetric blood flow by Doppler power using a Doppler flow wire. An in vitro model with serially connected silicone tubes of known lumen diameters (1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 mm) and pulsatile blood flow ranging from 10 to 200 mL/min was used. A Doppler flow wire was connected to a commercially available Doppler system (FloMap(R), Cardiometrics) for online calculation of the zeroth (M(0)) and the first (M(1)) Doppler moment, as well as mean flow velocity (V(m)). Two different groups of sample volumes (at different gate depths) were used: 1. two proximal sample volumes lying completely within the vessel were required to evaluate the effect of scattering and attenuation on Doppler power, and 2. distal sample volumes intersecting completely the vessel lumen to assess the vessel cross-sectional area. Area (using M(0)) and V(m) (using M(1)/M(0)) obtained from the distal gates were corrected for scattering and attenuation by the data obtained from the proximal gates, allowing calculation of absolute volumetric flow. These results were compared to the respective time collected flow. Correlation between time collected and Doppler-derived flow measurements was 0.98 (p < 0.0001), with a regression line close to the line of equality indicating an excellent agreement of the two measurements in each individual tube. The mean paired flow difference between the two techniques was 1.5 +/- 9.0 mL/min (ns). Direct volumetric blood flow measurement from received Doppler power using a Doppler flow wire system is feasible. This technique may potentially be of great clinical value because it allows an accurate assessment of coronary flow and flow reserve with a commercially available flow wire system.

Blood Flow Velocity↗

PubMed2000

Apolipoprotein B-100 gene Xba I polymorphism and cholesterol gallstone disease.

The apolipoprotein (apo) B gene Xba I polymorphism is associated with alterations in serum lipids. Disturbances in serum lipids may be a risk factor for cholesterol gallstone disease. However, the relation between the Xba I polymorphism and cholesterol gallstones is unknown. This study was aimed at characterizing the polymorphism of the apo B gene Xba I in patients with gallbladder stones and the association of Xba I polymorphism with serum lipids. Xba I genotypes were measured by PCR-RFLP, and serum lipids assayed in 190 patients with gallbladder stones and 441 control subjects. The frequency of the X+/- genotype (20.63 vs. 7.94%) and X+ allele (10.79 vs. 3.97%) was significantly higher in the patient group than in the control group. Patients with the X+/- genotype had a significantly higher concentration of total cholesterol, low-density lipoprotein (LDL)-cholesterol, and apo B in serum than patients with the X-/- genotype. The X+ allele of the apo B gene is characterized by a higher cholesterol concentration and a higher LDL-cholesterol concentration in serum, and it may be a marker for increased risk of cholesterol gallstone disease.

Alleles↗

PubMed2000

Characterization of calcium currents in functionally mature mouse spinal motoneurons.

Motoneurons integrate synaptic input and produce output in the form of trains of action potentials such that appropriate muscle contraction occurs. Motoneuronal calcium currents play an important role in the production of this repetitive firing. Because these currents change in the postnatal period, it is necessary to study them in animals in which the motor system is 'functionally mature', that is, animals that are able to weight-bear and walk. In this study, calcium currents were recorded using whole-cell patch-clamp techniques from large (> 20 microm) ventral horn cells in lumbar spinal cord slices prepared from mature mice. Ninety percent (nine out of 10) of the recorded cells processed for choline acetyltransferase were found to be cholinergic, confirming their identity as motoneurons. A small number of motoneurons were found to have currents with low-voltage-activated (T-type) characteristics. Pharmacological dissection of the high-voltage-activated current demonstrated omega-agatoxin-TK- (P/Q-type), omega-conotoxin GVIA- (N-type), and dihydropyridine- and FPL-64176-sensitive (L-type) components. A cadmium-sensitive component of the current that was insensitive to these chemicals (R-type) was also seen in these cells. These results indicate that the calcium current in lumbar spinal motoneurons from functionally mature mice is mediated by a number of different channel subtypes. The characterization of these calcium channels in mature mammalian motoneurons will allow for the future study of their modulation and their roles during behaviours such as locomotion.

Animals↗

PubMed2000

Dendritic L-type calcium currents in mouse spinal motoneurons: implications for bistability.

The intrinsic properties of mammalian spinal motoneurons provide them with the capability to produce high rates of sustained firing in response to transient inputs (bistability). Even though it has been suggested that a persistent dendritic calcium current is responsible for the depolarizing drive underlying this firing property, such a current has not been demonstrated in these cells. In this study, calcium currents are recorded from functionally mature mouse spinal motoneurons using somatic whole-cell patch-clamp techniques. Under these conditions a component of the current demonstrated kinetics consistent with a current originating at a site spatially segregated from the soma. In response to step commands this component was seen as a late-onset, low amplitude persistent current whilst in response to depolarizing-repolarizing ramp commands a low voltage clockwise current hysteresis was recorded. Simulations using a neuromorphic motoneuron model could reproduce these currents only if a noninactivating calcium conductance was placed in the dendritic compartments. Pharmacological studies demonstrated that both the late-onset and hysteretic currents demonstrated sensitivity to both dihydropyridines and the L-channel activator FPL-64176. Furthermore, the alpha1D subunits of L-type calcium channels were immunohistochemically demonstrated on motoneuronal dendrites. It is concluded that there are dendritically located L-type channels in mammalian motoneurons capable of mediating a persistent depolarizing drive to the soma and which probably mediate the bistable behaviour of these cells.

Animals↗

PubMed2000

Uncoupling of betaIIPKC from its targeting protein RACK1 in response to ethanol in cultured cells and mouse brain.

Protein kinase C (PKC) is involved in many neuroadaptive responses to ethanol in the nervous system. PKC activation results in translocation of the enzyme from one intracellular site to another. Compartmentalization of PKC isozymes is regulated by targeting proteins such as receptors for activated C kinase (RACKs). It is possible, therefore, that ethanol-induced changes in the function and compartmentalization of PKC isozymes could be due to changes in PKC targeting proteins. Here we study the response of the targeting protein RACK1 and its corresponding kinase betaIIPKC to ethanol, and propose a novel mechanism to explain how ethanol modulates signaling cascades. In cultured cells, ethanol induces movement of RACK1 to the nucleus without affecting the compartmentalization of betaIIPKC. Ethanol also inhibits betaIIPKC translocation in response to activation. These results suggest that ethanol inhibition of betaIIPKC translocation is due to miscompartmentalization of the targeting protein RACK1. Similar events occurred in mouse brain. In vivo exposure to ethanol caused RACK1 to localize to nuclei in specific brain regions, but did not affect the compartmentalization of betaIIPKC. Thus, some of the cellular and neuroadaptive responses to ethanol may be related to ethanol-induced movement of RACK1 to the nucleus, thereby preventing the translocation and corresponding function of betaIIPKC.

Animals↗

PubMed2000

Analysis of the M-shell spectra emitted by a short-pulse laser-created tantalum plasma

The spectrum of tantalum emitted by a subpicosecond laser-created plasma, was recorded in the regions of the 3d-5f, 3d-4f, and 3d-4p transitions. The main difference with a nanosecond laser-created plasma spectrum is a broad understructure appearing under the 3d-5f transitions. An interpretation of this feature as a density effect is proposed. The supertransition array model is used for interpreting the spectrum, assuming local thermodynamic equilibrium (LTE) at some effective temperature. An interpretation of the 3d-4f spectrum using the more detailed unresolved transition array formalism, which does not assume LTE, is also proposed. Fitted contributions of the different ionic species differ slightly from the LTE-predicted values.

Journal Article↗

PubMed2000

Aberrant splicing of tau pre-mRNA caused by intronic mutations associated with the inherited dementia frontotemporal dementia with parkinsonism linked to chromosome 17.

Frontotemporal dementia accounts for a significant fraction of dementia cases. Frontotemporal dementia with parkinsonism linked to chromosome 17 is associated with either exonic or intronic mutations in the tau gene. This highlights the involvement of aberrant pre-mRNA splicing in the pathogenesis of neurodegenerative disorders. Little is known about the molecular mechanisms of the splicing defects underlying these diseases. To establish a model system for studying the role of pre-mRNA splicing in neurodegenerative diseases, we have constructed a tau minigene that reproduces tau alternative splicing in both cultured cells and in vitro biochemical assays. We demonstrate that mutations in a nonconserved intronic region of the human tau gene lead to increased splicing between exon 10 and exon 11. Systematic biochemical analyses indicate the importance of U1 snRNP and, to a lesser extent, U6 snRNP in differentially recognizing wild-type versus intron mutant tau pre-mRNAs. Gel mobility shift assays with purified U1 snRNP and oligonucleotide-directed RNase H cleavage experiments support the idea that the intronic mutations destabilize a stem-loop structure that sequesters the 5' splice site downstream of exon 10 in tau pre-mRNA, leading to increases in U1 snRNP binding and in splicing between exon 10 and exon 11. Thus, mutations in nonconserved intronic regions that increase rather than decrease alternative splicing can be an important pathogenic mechanism for the development of human diseases.

Adult↗

PubMed2000

Overexpression of Na(+)-dependent myo-inositol transporter gene in mouse lens led to congenital cataract.

PURPOSE: Maintaining appropriate osmotic pressure is essential for maintaining lens transparency. This study was performed to investigate whether high levels of myo-inositol, one of the major organic osmolytes in the lens, would lead to cataract development. METHODS: Transgenic mouse lines carrying the bovine Na(+)-dependent myo-inositol transporter (bSMIT) cDNA under the control of the mouse alphaA-crystallin promoter were generated. RESULTS. Increased bSMIT expression was accompanied by increased myo-inositol level in the lens and increased uptake of (3H) myo-inositol by the lens in culture. The transgenic mice developed observable cataract under normal rearing conditions beginning at 2 to 8 weeks of age, and the severity of cataract development was correlated to the level of bSMIT gene expression and lens myo-inositol accumulation. For transgenic mouse line 3352, heterozygous mice did not develop cataract, whereas homozygous ones did. Prenatal feeding of heterozygous 3352 mice with high myo-inositol diet led to cataract development, indicating that cataract development was not merely due to a nonspecific effect of SMIT overexpression. Introducing aldose reductase overexpressing transgene into heterozygous 3352 mice also led to cataract development, indicating that this type of cataract is primarily due to osmotic stress. CONCLUSIONS: The present results indicate that high levels of myo-inositol and sorbitol in the lens contribute to cataract development. This is a useful model to study the role of osmotic stress in cataractogenesis during lens development.

Aldehyde Reductase↗