Biomedical subjects

K Wang

Publications and source records attributed to K Wang.

At least 127 records · Page 7Linked to original sources

PubMed2001

Intestinal neuronal dysplasia-like pathology in Ncx/Hox11L.1 gene-deficient mice.

BACKGROUND/PURPOSE: Ncx/Hox11L.1-deficient (Ncx-/-) mice specifically created by the authors had mega-ileo-ceco-colon (mega-ICC) with a caliber change in the proximal colon. The authors studied the nerve distribution in the bowel of these Ncx-/- mice to determine the cause of their bowel dysmotility. METHODS: Four-week-old Ncx-/- mice (n = 10; 5 with mega-ICC, 5 without mega-ICC) were killed and the bowel harvested. Half of each specimen was snap frozen for AchE and NADPH-diaphorase histochemistry, and the other half were fixed with 10% formalin for H&E staining and immunohistochemistry using PGP9.5 antibody (a marker for neurons), C-kit antibody (a marker for intestinal pacemaker cells), and stem cell factor antibody (a marker for C-kit ligand). Age-matched wild-type normal mice (n = 5) served as controls. RESULTS: In the ileum, cecum, and proximal colon from all Ncx-/- mice (irrespective of the association of mega-ICC), typical findings of human intestinal neuronal dysplasia (IND) ie, obvious hyperganglionosis in neuronal plexuses on PGP9.5 immunohistochemistry, ectopic ganglia in the mucosal and muscular layers on AchE histochemistry, and ghostlike ganglia on NADPH-diaphorase histochemistry were found. Likewise, in normal caliber distal colon from these mice, the distribution of ganglion cells, C-kit, and stem cell factor was normal. In control specimens, there was no ectopic ganglia or hyperganglionosis. CONCLUSIONS: These findings suggest that the Ncx/Hox11L.1 gene is required for the proper innervation of the enteric nervous system in mice, and our deficient strain may be useful as a model for studying IND in humans.

Animals↗

PubMed2001

Optimal dosing of intravascular low-power red laser light as an adjunct to coronary stent implantation: insights from a porcine coronary stent model.

BACKGROUND: It is believed that restenosis following coronary interventions is the result of endothelial denudation that leads to thrombus formation, vascular remodeling, and smooth muscle cell proliferation. Low-power red laser light (LPRLL) irradiation enhances endothelial cell growth in vitro and in vivo, and reduces restenosis in animal models. The present study investigated the optimal dose of intravascular LPRLL therapy in the prevention of in-stent stenosis in a porcine coronary stent model. METHODS AND RESULTS: Selected right coronary artery segments were pretreated with a LPRLL balloon, delivering a dose of 0 mW during 1 min (group 1, n = 10), 50 mW during 1 min (group II, n = 10), or 100 mW during 1 min (group III, n = 10) before stenting. Quantitative coronary analysis of the stented vessel was performed before stenting, immediately after stenting, and at 6 weeks follow-up. The pigs were sacrificed, and histologic and morphometric analyses were conducted. At 6 weeks, minimal luminal stent diameter was significantly narrower in the control group compared to the 50-mW dose group (p < 0.05). These results were confirmed by morphometric analysis. Neointimal area was also significantly decreased in the 50-mW dose group. CONCLUSIONS: Intravascular LPRLL contributes to reduction of angiographic in-stent restenosis and neointimal hyperplasia in this animal model. The optimal dose using the LPRLL balloon system seems to be approximately 5 mW delivered during 1 min.

Animals↗

PubMed2001

Prolonged Hya-disparate skin graft survival in ethanol-consuming mice: correlation with impaired delayed hypersensitivity.

BACKGROUND: Ethanol consumption impairs cell-mediated immunity and enhances humoral immunity. Among cell-mediated immune reactions, little is known of the effect of ethanol on chronic graft rejection. Allograft responses against the male-specific minor histocompatibility antigen, Hya, are widely used to study chronic graft rejection. METHODS: Female C57BL/6 (B6) mice were fed ethanol-containing liquid diets, were pair-fed an isocaloric liquid control diet, or were fed solid diet and water ad libitum. One week after diet initiation, the mice were grafted with split thickness, orthotopic male tail skin grafts, and the integrity of the grafts was monitored as the diet continued. Delayed hypersensitivity (DTH) was also determined in these same mice. In addition, Hya-cytolytic T-cell-deficient syngeneic major histocompatibility complex mutant B6.C-H2bm13 (bm13) and B6.C-H2bm14 (bm14) mice were assessed for skin graft rejection, DTH, and cytotoxic T-lymphocyte (CTL) activity. RESULTS: Ethanol-consuming female B6 mice are impaired in their ability to reject syngeneic male skin grafts and to develop Hya-specific DTH responses. To address the underlying mechanism, we show that Hya graft rejection correlates with DTH and not with CTL activity. Female B6 mice clearly differ from female bm13 and bm14 mice in their ability to generate CTLs against Hya antigen. Despite their inability to make Hya-specific CTL responses, bm13 and bm14 female mice, nevertheless, make Hya-specific DTH responses and ultimately reject Hya-disparate skin grafts, indicating that Hya-specific graft rejection results from DTH. Ethanol, by impairing Hya-specific DTH, inhibits Hya-specific skin graft rejection. CONCLUSIONS: We demonstrate that ethanol consumption impairs Hya-specific graft rejection. In addition, experiments with mice unable to generate anti-Hya CTLs support previous observations suggesting that DTH responses are sufficient to cause rejection of Hya-incompatible grafts.

Alcohol Drinking↗

PubMed2001

Development of novel dye-doped silica nanoparticles for biomarker application.

We report the development of novel luminescent nanoparticles composed of inorganic luminescent dye, Tris(2,2'-bipyridyl) dichlororuthenium (II) hexahydrate, doped inside a silica network. These dye doped silica (DDS) nanoparticles have been synthesized using a water-in-oil microemulsion technique in which controlled hydrolysis of the tetraethyl orthosilicate leads to the formation of monodispersed nanoparticles. They are prepared with a variety of sizes: small (5+/-1 nm), medium (63+/-4 nm), and large (400+/-10 nm), which shows the efficiency of the microemulsion technique for the synthesis of uniform nanoparticles. All these nanoparticles are suitable for biomarker application since they are much smaller than cellular dimension. These nanoparticles are highly photostable in comparison to most commonly used organic dyes. These nanoparticles have been characterized by various microscopic and spectroscopic techniques. The amount of dye content in these nanoparticles has been optimized to eliminate self-quenching. It has been observed that maximum luminescence intensity is achieved when the dye content is around 20 wt%. Silica surface of DDS nanoparticles is available for surface modification and bioconjunction. For demonstration as a biomarker, the DDS nanoparticle's surface has been biochemically modified to attach membrane-anchoring groups and applied successfully to stain human leukemia cells.

2,2'-Dipyridyl↗

PubMed2001

Comparison between visual and passive acoustic detection of finless porpoises in the Yangtze River, China.

Recently, sonar signals and other sounds produced by cetaceans have been used for acoustic detection of individuals and groups in the wild. However, the detection probability ascertained by concomitant visual survey has not been demonstrated extensively. The finless porpoises (Neophocaena phocaenoides) have narrow band and high-frequency sonar signals, which are distinctive from background noises. Underwater sound monitoring with hydrophones (B&K8103) placed along the sides of a research vessel, concurrent with visual observations was conducted in the Yangtze River from Wuhan to Poyang Lake in 1998 in China. The peak to peak detection threshold was set at 133 dB re 1 ,EPa. With this threshold level, porpoises could be detected reliably within 300 m of the hydrophone. In a total of 774-km cruise, 588 finless porpoises were sighted by visual observation and 44 ,864 ultrasonic pulses were recorded by the acoustical observation system. The acoustic monitoring system could detect the presence of the finless porpoises 82% of the time. A false alarm in the system occurred with a frequency of 0.9%. The high-frequency acoustical observation is suggested as an effective method for field surveys of small cetaceans, which produce high-frequency sonar signals.

Animals↗

PubMed2001

Cardiac myosin autoimmunity in acute Chagas' heart disease.

Infection with Trypanosoma cruzi, the agent of Chagas' disease, may induce antibodies and T cells reactive with self antigens (autoimmunity). Because autoimmunity is generally thought to develop during the chronic phase of infection, one hypothesis is that autoimmunity develops only after long-term, low-level stimulation of self-reactive cells. However, preliminary reports suggest that autoimmunity may begin during acute T. cruzi infection. The goal of the present study was to investigate whether cardiac autoimmunity could be observed during acute T. cruzi infection. A/J mice infected with the Brazil strain of T. cruzi for 21 days developed severe myocarditis, accompanied by humoral and cellular autoimmunity. Specifically, T. cruzi infection induced immunoglobulin G (IgG) autoantibodies and delayed type hypersensitivity (DTH) to cardiac myosin. This autoimmunity resembles that which develops in A/J mice immunized with myosin in complete Freund's adjuvant in that myosin-specific antibodies and DTH responses both develop by 21 days postinfection or postimmunization. While the levels of myosin IgG in T. cruzi-infected mice were slightly lower than those in myosin-immunized mice, the magnitude of myosin DTH in the two groups was statistically equivalent. In contrast, C57BL/6 mice, which are resistant to myosin-induced myocarditis and its associated autoimmunity, developed undetectable or low levels of myosin IgG and did not exhibit myosin DTH or myocarditis upon T. cruzi infection. Therefore, humoral and cellular cardiac autoimmunity can develop during acute T. cruzi infection in the genetically susceptible host.

Animals↗

PubMed2001

The 2.2-kilobase latency-associated transcript of herpes simplex virus type 2 does not modulate viral replication, reactivation, or establishment of latency in transgenic mice.

To better understand the mechanisms responsible for the observed effects of deletions in the promoter region of the latency-associated transcript (LAT) gene in impairing herpes simplex virus (HSV) reactivation, we generated mice transgenic for a 5.5-kb HSV type 2 (HSV-2) genomic fragment spanning the major LAT, along with the LAT promoter and flanking regions, in the C57BL/6 background. The mice expressed abundant 2.2-kb major LATs in trigeminal ganglia (TG) and other tissues. The effects of the transgene on HSV-2 infection, latency, and reactivation were assessed. When infected with wild-type (WT) HSV-2 or its LAT promoter deletion (LAT(-)) mutant, primary lung fibroblast lines established from normal C57BL/6 and transgenic mice supported virus growth equally well. The replication of these viruses in the mouse eye and their spread to TG and brains were similar. The quantities of latent viral DNA in TG of transgenic and normal mice, as determined by real-time PCR, were comparable. UV light-induced reactivation of the LAT(-) mutant from transgenic mice (0 to 7%) was no more frequent than that from normal mice (0 to 14%), while WT virus was reactivated from 13 to 54% of normal mice and 22 to 54% of transgenic mice. The cumulative data indicate that, when expressed transgenically, the HSV-2 major LAT cannot influence HSV-2 infection or latency and cannot complement the defect in reactivation of the LAT(-) mutant. These results imply that the phenotype of reduced reactivation associated with the LAT(-) mutant is related to a function encoded in the LAT promoter but not to the major LAT itself.

Animals↗

PubMed2001

Power to detect linkage based on multiple sets of data in the presence of locus heterogeneity: comparative evaluation of model-based linkage methods for affected sib pair data.

The development of rigorous methods for evaluating the overall strength of evidence for genetic linkage based on multiple sets of data is becoming increasingly important in connection with genomic screens for complex disorders. We consider here what happens when we attempt to increase power to detect linkage by pooling multiple independently collected sets of families under conditions of variable levels of locus heterogeneity across samples. We show that power can be substantially reduced in pooled samples when compared to the most informative constituent subsamples considered alone, in spite of the increased sample size afforded by pooling. We demonstrate that for affected sib pair data, a simple adaptation of the lod score (which we call the compound lod), which allows for intersample admixture differences can afford appreciably higher power than the ordinary heterogeneity lod; and also, that a statistic we have proposed elsewhere, the posterior probability of linkage, performs at least as well as the compound lod while having considerable computational advantages. The companion paper (this issue, pp 217-225) shows further that in application to multiple data sets, familiar model-free methods are in some sense equivalent to ordinary lod scores based on data pooling, and that they therefore will also suffer dramatic losses in power for pooled data in the presence of locus heterogeneity and other complicating factors.

Chromosome Mapping↗

PubMed2001

Sequential sampling plans for western flower thrips (Thysanoptera: Thripidae) on greenhouse cucumbers.

The development of cost-effective and reliable sampling programs for the management of western flower thrips, Frankliniella occidentalis (Pergande), on greenhouse cucumbers is important for getting growers to adopt economic injury levels and economic thresholds. The objectives of this study were to develop two sequential sampling plans. A fixed-precision sequential sampling plan was designed for estimating F. occidentalis adult density at a fixed-precision level on cucumber flowers. Also, a sequential sampling plan for classifying thrips population levels as below or above economic thresholds was developed to assist in decision making for the timing of pesticide applications. Both sequential sampling plans were validated using a resampling simulation technique on nine independent data sets ranging in density from 1.25 to 12.95 adults per flower. With the fixed-precision sampling plan, average means obtained in 100 repeated simulation runs were within the 95% CI of the estimated mean for all data sets. Appropriate levels of precision for the different population densities were recommended based on the simulation results. With sequential sampling for classifying the population levels of thrips in terms of an economic threshold, it has the advantage of requiring smaller sample sizes to determine the population status when the population densities differ greatly from the critical density (i.e., economic threshold). However, this plan needs a great number of samples when population density is close to the critical density. In this case, use of a combination of both sampling plans is recommended.

Animals↗

PubMed2001

Ultrasensitive optical DNA biosensor based on surface immobilization of molecular beacon by a bridge structure.

A novel biotinylated molecular beacon (MB) probe was developed to prepare a DNA biosensor using a bridge structure. MB was biotinylated at the quencher side of the stem and linked on a biotinylated glass cover slip through streptavidin, which acted as a bridge between MB and glass matrix. An efficient fluorescence microscope system was constructed to detect the fluorescence change caused by the conformation change of MB in the presence of complementary DNA target. The proposed biosensor was used to directly detect, in real-time, the target DNA molecules. The bridge immobilization method caused the proposed DNA biosensor to have a faster and more stable response. Under the optimal conditions, the newly developed DNA biosensor showed a linear response toward ssDNA in the range of 5-100 nM with a detection limit of 2 nM. It was interesting to note that the described biosensor was reproducible after being regenerated by urea.

Biosensing Techniques↗

PubMed2001

Visual p3 in female alcoholics.

BACKGROUND: The P300 (P3) component of the event related potential has been established as a sensitive risk marker of vulnerability to alcoholism. Most alcoholism studies have focused on men; recent studies indicate that women are equally vulnerable to developing alcoholism. METHODS: Visual P3 recorded from 31 electrode positions was evaluated in 44 alcoholic and 60 control women, 24-50 years of age. P3 amplitudes and latencies of the two groups were statistically compared using Analysis of Variance; source localization of surface amplitude values from each group were plotted using a low-resolution brain electromagnetic tomography. RESULTS: The results indicated that alcoholic women had significantly smaller P3 amplitudes in the frontal and central regions compared with controls. Source localization showed lowered activation in alcoholic women in right dorso-lateral prefrontal cortex and the ventro-medial fronto-central regions. CONCLUSIONS: The results suggest that P3 is an equally sensitive endophenotypic marker of vulnerability to alcoholism in women. The findings are discussed in terms of functional and physiologic significance of the P3 amplitude in alcoholic women and its relationship to drinking behaviors.

Adult↗

PubMed2001

[Phosphorus loss potential of soil-water in sites of the main rice-yield area in the Northern Zhejiang].

Phosphorus (P) loss potential and its environmental impact from soil-water were surveyed in Jiashan Yuyao, Deqing and Yuhang, named main rice-yield areas in Northern Zhejiang province China. High P input has resulted in soil P accumulation. Higher soil Olsen-P contributed its bio-available P, water extracted P and increased soil P loss potential. The role of P in paddy soils is of environmental rather than agronomic concern in the process of soil P build-up. During the no-rice time, total P (TP) concentration in the various water including ditch drain inside/outside field, field surface water and pipe drain et al are over the critical values associated with accelerated waters eutrophication. The average proportion of dissolved reactive P (DRP) concentration in TP was 40%, however, these current DRP levels in partly ditch drain outside field and surface or ground water in no-rice time could not caused serious impact to the outside waters nearby rice-yield agriculture area. No significant line correlation between soil P tests and P in field surface water was found in no-rice time due to differences in field tillage among rice-yield areas, while P application increased both soil P and its correspondingly field surface P level after rice was planted at the same time.

Oryza↗

PubMed2001

[The expression of uridine diphosphate glucuronosyltransferase mRNA regulated by alcohol].

OBJECTIVE: To investigate whether ethanol and isopentanol could modulate the drug metabolism by regulating uridine diphosphate glucuronosyltransferase (UGT) expression in rat livers and cultured rat hepatocytes. METHODS: Rat livers and primary rat hepatocyte cultures have been used to determine the mRNA levels of five UGT isoenzymes following treatment with ethanol and isopentanol. RESULTS: Following treatment with alcohol in rats, UGT1A1 mRNA and UGT1A5 mRNA were increased to a mean of 177% and 166% of control, respectively. The mRNA levels of UGT2B1 and UGT2B3 were also increased in alcohol-treated rats to 178% and 132% of control, respectively. Incubation of hepatocytes with ethanol and isopentanol significantly increased the mRNA expression of UGT1A1, UGT1A5, UGT2B1 and UGT2B3 mRNA. CONCLUSIONS: The expression of UGT can be regulated by ethanol and isopentanol. As a result, chronic alcohol consumption may modify the metabolism of numerous endogenous and exogenous compounds, in particular some drugs, which are substrates of these UGT isoenzymes.

Animals↗

PubMed2001

Bladder transplantation in rats using FK-506.

PURPOSE: We created viable bladder tissue by transplantation with immunosuppression. MATERIALS AND METHODS: For bladder transplantation the bladder of newborn Brown-Norway rats was excised and each was transplanted into a pouch created in the distal omentum of a 5-week-old Lewis rat. In 15 group 1 rats no immunosuppressive agent was used. In 20 group 2 rats 0.6 mg./kg. FK-506 daily were given intramuscularly until a predetermined day of harvest. Recipient rats were sacrificed on day 3, 5, 7 or 14 after bladder transplantation, and the bladder grafts were harvested and formalin fixed. Hematoxylin and eosin staining was done to examine bladder graft survival and the degree of rejection, and immunohistochemical testing was performed for assessing the vesical nervous system. In 5 rats in the control group bladder augmentation was performed by anastomosing the bladder graft to the native bladder. Each augmented bladder was harvested 21 days later for histopathological assessment. RESULTS: Overall bladder graft survival was 96.4%. Each successfully transplanted bladder graft appeared macroscopically as a thin walled cyst. In group 1 all bladder grafts showed rejection with cellular infiltration. In group 2 there was mild rejection in 5 rats and no evidence of rejection in the remaining 15. All group 2 bladder grafts had intact nerve distribution. Bladder augmentation was successful in all 5 cases and the mucosa was normal throughout each augmented bladder. CONCLUSION: Because FK-506 successfully prevents rejection, our technique would appear to have the potential for creating viable bladder tissue that may be used for bladder augmentation in cases of vesical exstrophy or neurogenic bladder.

Animals↗

PubMed2001

[Therapeutic potential of recombinant adenovirus expressing p53 in hepatocellular carcinoma cell lines].

OBJECTIVE: To investigate the effects of the recombinant adenoviral vector Ad-p53 on the biological behavior of hepatocellular carcinoma (HCC) cells in vitro and in vivo. METHODS: With recombinant adenoviral vector expressing WT-p53 (Ad-p53), p53 gene was transfected into the HCC cell line, PLC/PRF/5. The cytotoxicities of Ad-p53 to cells were measured by MTT assay. Cell growth properties and cell cycle patterns were assessed with flow cytometry. The animal model was developed by injecting HCC cells into the dorsum of nude mice. Ad-p53 was injected intratumorally. The animals were killed, and then excised tumors were weighed and analyzed for p53 and p21 protein expression using western blot assay. RESULTS: The introduction of exogenous wild-type p53 resulted in the inhibition of cell growth, high G2/M ratio and cell apoptosis, and low S ratio in PLC/PRF/5. The expression of both p53 and p21 proteins was upregulated in the cells. CONCLUSIONS: Replication-deficient adenoviral vector expressing WT-p53 may be useful for gene therapy of HCC.

Adenoviridae↗

PubMed2001

[Correlation of c-myc gene amplification, MTS1/p16 gene alternation, and HBV infection in human hepatocellular carcinoma].

OBJECTIVE: To observe the roles of c-myc gene amplification, MTS1/p16 gene alternation, and HBV infection in the pathogenesis and progression of hepatocellular carcinoma (HCC). METHODS: A d-PCR-PAGE-laser scanning technique was used to define amplifications of c-myc oncogene. Alternations of MTS1/p16 gene exon1 and exon2 were analysed by PCR and single-strand conformation polymorphism (SSCP) silver stain method. HBV-DNA was assayed by PCR. RESULTS: (1)The positive rates of c-myc gene amplification of HCCs and their paired non-cancerous liver tissues were 44.83% (13/29) and 51.72% (15/29). The discrepancies between them were not significant (P>0.05), but they were both significantly higher than that of cirrhotic liver tissues (8.33%, 1/12, P<0.05). (2)A total of 3 homozygous deletions and no mutations of MTS1/p16 gene exon1 and exon2 in HCCs were found in the subset of HCCs. (3)The discrepancies of the positive rates of HBV-DNA among normal liver (14.29%, 2/14), cirrhotic liver (66.67%, 8/12) and HCCs (96.55%, 28/29) were significant (P<0.001). Moreover, the HBV-DNA positive rates increased according to the development of liver lesions (b=0.3986, P<0.001). CONCLUSIONS: (1)C-myc gene amplification and HBV infection are closely related to the development and progression in a subset of HCCs. However, c-myc gene amplification does not correlate with the HBV infection in HCCs. (2)The homozygous deletions and mutations of MTS1/p16 gene are infrequently encountered in the subset of HCCs.

Carcinoma, Hepatocellular↗

PubMed2001

[Phosphorus behavior in soil-water system of paddy field and its environmental impact].

A field experiment with rice showed that P fertilizer application increased the concentrations of resin P in soil and total P in soil surface water, and both of them declined subsequently over time. Compared with applying mineral P fertilizer only, the integrated application of mineral-P and manure resulted in a higher resin P level within 20 days after P application. The total P concentration in soil surface water in the treatment of integrated application of mineral-P and manure was 3.4 times higher than that in the treatment of mineral-P fertilizer application only after 7 days of P application, and also, was 2.8 times higher than that in the treatment where P application rate was doubled. The potential of Ploss from surface water in the treatment of integrated application with manure was more than that in the treatment of applying-P fertilizer only. The effect of applied P sorts on P concentration in soil surface water could be ignored after 33 days of P application. Two drainages were conducted for rice growth, which caused the net P loss loading and its apparent P loss ratio in range of -0.038-0.076 kg.m-2 and 0.034-0.100%, respectively. To minimize P loss from rice production area, field drainage should be avoided in the initial week of P-fertilizer application or field harrowing.

Environment↗

PubMed2001

[Diagnosis of breast-duct disease by breast duct endoscope].

OBJECTIVES: To study the pathological characteristics of breast-duct disease under breast duct endoscope in diagnosis and treatment of breast diseases. METHODS: The images of breast duct of 62 patients with nipple discharge were obtained by hard breast duct endoscope (Olympus Inc) and computer assistant analysis system. RESULTS: Of the 62 patients, malignant tumor was found in 4, premalignancy in 6, intradutal papilloma in 15, and mammary duct or plasma cell mastitis in 37. CONCLUSIONS: Intraductal lesions of patients with nipple discharge can be observed and be followed up with breast duct endoscope. The accuracy of etiological diagnosis of patients with nipple discharge, after the use of breast duct endoscope can partly modify the indications for operation in patients with nipple discharge.

Adolescent↗