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Biomedical subjects

L Liang

Publications and source records attributed to L Liang.

At least 91 records · Page 5Linked to original sources
PubMed1999

[Study on therapeutic effect of carnitine on hepatic steatosis caused by total parenteral nutrition in rats].

OBJECTIVE: To study the hepatic steatosis-minimizing effects of carnitine supplemented total parenteral nutrition (TPN). METHODS: Eighteen normal Wistar rats and nineteen cirrhotic Wistar rats were randomly divided into three groups, respectively: group A (12), chow and libitum; group B (13), TPN for one week group C (12), TPN with carnitine. Liver functions were tested at the seventh day, and also, the liver was resected for histological studies and lipid content determination. RESULTS: Hepatic lipid content was significantly elevated and hepatic steatosis was noted in group B. Hepatic lipid content and hepatic lipid deposit were significantly lowered when carnitine was added to the TPN solution. CONCLUSIONS: Carnitine can minimize hepatic steatosis caused by TPN.

Animals↗
PubMed1999

[Hepatic arterial infusion of 32P-radionuclide microspheres for radiation therapy of hepatocellular carcinoma].

OBJECTIVE: To investigate the efficacy of internal radiation of (32)P-glass microspheres ((32)P-GMS) in unresected hepatocellular carcinoma (HCC) via subcutaneous arterial port. METHODS: Hepatic arterial (99)technetium-macroaggregate albumin ((99)Tc-MAA) scanning via subcutaneous arterial port was undertaken to measure lung/liver shunting ratio and tumor/liver ratio. Hepatic arterial infusion of (32)P-GMS was performed in 17 cases of HCC with a dose from 1.11 to 1.30 GBq. Twenty cases of HCC undergoing hepatic arterial chemoembolization (HACE) in the same period served as controls group. RESULTS: There was no treatment-related death in the 17 cases. In 7 of the 17 cases, AFP level and/or tumor size decreased by 50% after treatment, with a response rate of 64.7%. The median survival time was 5.5 months, and the 3-, 6-, 9-, 12-month survival rates were 94.1%, 44.1%, 31.0%, 24.4%, respectively. The therapeutic efficacy was better than that of HACE. The survival time was significantly longer in patients with T/N ratio >or= 2 than in those with T/N < 2 (P < 0.05). CONCLUSIONS: Hepatic arterial infusion of (32)P-GMS is an alternative treatment for unresected HCC.

Adult↗
PubMed1999

[Analysis of the isomers of dihydroxybenzenes by micellar electrokinetic capillary chromatography with on-column amperometric detection at carbon-fiber microelectrode].

The effects of the concentrations of beta-cyclodextrin(CD) in electrolyte on the cyclic voltammetric properties of o-, m-, p-dihydroxybenzenes at carbon-fiber microelectrode were studied. The inclusion between o-, m-, p-dihydroxybenzenes and beta-CD was investigated based on the molecular structures and experimental results. The study showed that the order of the inclusion interaction, from strong to weak, between dihydroxybenzenes and beta-CD, was m-, o- and p-dihydroxybenzenes. The effects of the concentrations of NH4Cl, SDS and beta-CD, and the pH values of the electrophoretic buffer on the migration time of o, m, p-dihydroxybenzenes were investigated. The assay of o, m, p-dihydroxybenzenes by micellar electrokinetic capillary chromatography with on-column amperometric detection at carbon-fiber microelectrode was developed. The recovery ranged from 98% to 103%.

Carbon↗
PubMed1998

Growth hormone-dependent tyrosine phosphorylation of a GH receptor-associated high molecular WEIGHT protein immunologically related to JAK2.

A critical step in growth hormone (GH) signalling is the GH-induced activation of the GH receptor (GHR)-associated tyrosine kinase, JAK2. JAK2 is a 120 kD member of the Janus family of tyrosine kinases, whose other mammalian members include JAK1, JAK3, and TYK2. Using 3T3-F442A murine preadipocytes, we now report detection of a Mr approximately 170 kD protein, referred to as HMW ("high molecular weight") JAK2, that is specifically reactive in immunoprecipitation and immunoblotting experiments with three independently-derived anti-JAK2 antibodies--two directed at carboxyl-terminal regions of the molecule and one directed at the amino-terminus. Like JAK2, HMW JAK2 is tyrosine phosphorylated in response to GH treatment of cells and is coimmunoprecipitated with anti-GHR serum. Thus, HMW JAK2 is a protein not heretofore described that is immunologically related to JAK2 and is physically and functionally associated with the GHR.

3T3 Cells↗
PubMed1998

H+ISFET-based biosensor for determination of penicillin G.

A biosensor based on an H+ ion sensitive field effect transistor (H+(-)ISFET) and penicillin G acylase has been developed. The response time of the sensor to different concentrations of penicillin G was 30 s. In a 20 mM phosphate buffer at pH 7.0, the linear range of the calibration curve was from 0.5 to 8 mM. The coefficients of variation for three samples with 20 repeated measurements were below 5%. Stability of the sensor could reach about 6 months and more than 1000 runs were performed without a significant decrease of the output value. The sensor was tested for measurement of the penicillin G content in penicillin fermentation both. Forty samples with low and high concentrations of penicillin G were chosen for the correlation test. The values assayed by the sensor method were compared with the values assayed by HPLC method, the correlation coefficient (r) was 0.9944 and the regression equation was y = 1.034X - 2083.7, respectively. The different measuring methods are discussed in the text.

Biosensing Techniques↗
PubMed1998

Structural requirements for major histocompatibility complex class II invariant chain endocytosis and lysosomal targeting.

The invariant chain (Ii) targets newly synthesized major histocompatibility complex class II complexes to a lysosome-like compartment. Previously, we demonstrated that both the cytoplasmic tail (CT) and transmembrane (TM) domains of Ii were sufficient for this targeting and that the CT contains two di-leucine signals, 3DQRDLI8 and 12EQLPML17 (Odorizzi, C. G., Trowbridge, I. S., Xue, L., Hopkins, C. R., Davis, C. D., and Collawn, J. F. (1994) J. Cell Biol. 126, 317-330). In the present study, we examined the relationship between signals required for endocytosis and those required for lysosomal targeting by analyzing Ii-transferrin receptor chimeras in quantitative transport assays. Analysis of the Ii CT signals indicates that although 3DQRDLI8 is necessary and sufficient for endocytosis, either di-leucine signal is sufficient for lysosomal targeting. Deletions between the two signals reduced endocytosis without affecting lysosomal targeting. Transplantation of the DQRDLI sequence in place of the EQLPML signal produced a chimera that trafficked normally, suggesting that this di-leucine sequence coded for an independent structural motif. Structure-function analysis of the Ii TM region showed that when Ii TM residues 11-19 and 20-29 were individually substituted for the corresponding regions in the wild-type transferrin receptor, lysosomal targeting was dramatically enhanced, whereas endocytosis remained unchanged. Our results therefore demonstrate that the structural requirements for Ii endocytosis and lysosomal targeting are different.

Amino Acid Sequence↗
PubMed1998

Virtual MRI endoscopy of the intracranial cerebrospinal fluid spaces.

We used constructive interference in steady state (CISS) 3D Fourier transform (3DFT) MRI data sets to obtain three-dimensional (3D) virtual MRI endoscopic views of the intracranial cerebrospinal fluid (CSF) spaces, processing them with a commercially available perspective endoscopic algorithm. We investigated the potential of the intracranial virtual MRI endoscopy applied to visualisation of the pathology in 13 patients with surgically confirmed trigeminal neuralgia (3), hemifacial spasm (3), acoustic neuroma (3), suprasellar germinoma (1), Langerhans cell histiocytosis (1), lateral ventricle nodules (1) and pituitary dwarfism (1). All images were acquired using a 1.5-T imager employing a circular polarised head coil. The CISS-3DFT data sets were transferred to a workstation for processing with the perspective endoscopic algorithm. Postprocessing for virtual MRI endoscopy was possible for all data sets. The lesions in 12 patients, and their complex anatomical relationships with the surrounding structures, were well seen on the 3D images. A small acoustic neuroma in the internal auditory meatus was not seen using virtual endoscopy. Although virtual MRI endoscopy has limitations, it provides 3D images which cannot be acquired using any other procedure.

Adolescent↗
PubMed1998

Anti-p53 antibodies in patients with Barrett's esophagus or esophageal carcinoma can predate cancer diagnosis.

BACKGROUND & AIMS: We previously discovered anti-p53 antibodies predating a cancer diagnosis in subjects at increased risk for liver, lung, breast, and prostate cancer. Recently, we reported a significant correlation (P < 0.017) between p53 antibodies and p53 mutations in patients with late-stage esophageal carcinoma. Because others have reported p53 mutations and overexpression of p53 protein in Barrett's esophagus, we studied p53 antibodies in plasma of 88 serially endoscoped patients: 36 with Barrett's metaplasia, 23 with esophageal squamous cell carcinoma, 10 with esophageal adenocarcinoma, and 19 with esophagitis or normal esophagus. METHODS: We used enzyme immunoassay, immunoblotting, and immunoprecipitation assays for p53 antibodies; polymerase chain reaction, denaturant gradient gel electrophoresis, and sequencing for p53 mutations; and immunohistochemistry for p53 protein. RESULTS: p53 antibodies were detected in 4 patients with Barrett's esophagus, including 1 with dysplasia that later progressed to adenocarcinoma, and in 10 cancer patients (P = 0.002) (8 squamous and 2 adenocarcinoma), 2 of whom (1 squamous, 1 adenocarcinoma) had antibodies before cancer was diagnosed. Other patient groups were too small for informative statistical analysis. Six antibody-positive cancer patients had p53 mutations, whereas 2 patients with cancer and 1 with Barrett's esophagus with antibodies had p53 protein overexpressed in esophageal tissues. CONCLUSIONS: Patients with Barrett's esophagus and esophageal cancer can develop p53 antibodies that may predate the clinical diagnosis of malignancy.

Adenocarcinoma↗
PubMed1998

Aiolos regulates B cell activation and maturation to effector state.

Aiolos encodes a zinc finger DNA-binding protein that is highly expressed in mature B cells and is homologous to Ikaros. In the periphery of mice homozygous for an Aiolos-null mutation, B cells exhibit an activated cell surface phenotype and undergo augmented antigen receptor (BCR)-mediated in vitro proliferative responses, even at limiting amounts of stimulant. In vivo, T cell-dependent B cell responses, including the formation of germinal centers and elevated serum IgG and IgE, are detected in Aiolos-deficient mice in the absence of immunization. Auto-antibodies and development of B cell lymphomas are frequently seen among aging Aiolos mutants. In sharp contrast to conventional B cells, B cells of the peritoneum, of the marginal zone, and the recirculating bone marrow population are greatly reduced.

Animals↗
PubMed1998

A crystallographic and molecular modeling study of butyrophenones.

The X-ray crystal structures of four butyrophenone analogues have been completed and are reported herein. These include spiperone hydrochloride (I), N-methylspiperone hydrochloride (II), pimozide (III), and fluspirilene (IV). These structures were compared to other structurally similar molecules with similar pharmacological activity. In addition, a molecular modeling study was done in order to determine the low energy conformations of these molecules. It was found that calculations of parameters that describe the molecular conformations showed that all four molecules were structurally similar. Crystallographic data: [see text]

Butyrophenones↗
PubMed1998

Inhibition of herpes simplex virus replication by a 2-amino thiazole via interactions with the helicase component of the UL5-UL8-UL52 complex.

With the use of a high-throughput biochemical DNA helicase assay as a screen, T157602, a 2-amino thiazole compound, was identified as a specific inhibitor of herpes simplex virus (HSV) DNA replication. T157602 inhibited reversibly the helicase activity of the HSV UL5-UL8-UL52 (UL5/8/52) helicase-primase complex with an IC50 (concentration of compound that yields 50% inhibition) of 5 microM. T157602 inhibited specifically the UL5/8/52 helicase and not several other helicases. The primase activity of the UL5/8/52 complex was also inhibited by T157602 (IC50 = 20 microM). T157602 inhibited HSV growth in a one-step viral growth assay (IC90 = 3 microM), and plaque formation was completely prevented at concentrations of 25 to 50 microM T157602. Vero, human foreskin fibroblast (HFF), and Jurkat cells could be propagated in the presence of T157602 at concentrations exceeding 100 microM with no obvious cytotoxic effects, indicating that the window between antiviral activity and cellular toxicity is at least 33-fold. Seven independently derived T157602-resistant mutant viruses (four HSV type 2 and three HSV type 1) carried single base pair mutations in the UL5 that resulted in single amino acid changes in the UL5 protein. Marker rescue experiments demonstrated that the UL5 gene from T157602-resistant viruses conferred resistance to T157602-sensitive wild-type viruses. Recombinant UL5/8/52 helicase-primase complex purified from baculoviruses expressing mutant UL5 protein showed complete resistance to T157602 in the in vitro helicase assay. T157602 and its analogs represent a novel class of specific and reversible anti-HSV agents eliciting their inhibitory effects on HSV replication by interacting with the UL5 helicase.

Amino Acid Sequence↗
PubMed1998

Correlation of MR imaging-determined cerebral blood volume maps with histologic and angiographic determination of vascularity of gliomas.

OBJECTIVE: Our purpose was to evaluate the relationships between the ratio of maximum relative cerebral blood volume (rCBV) (rCBV ratio = rCBV[tumor]/rCBV[contralateral white matter]) and histologic and angiographic vascularities of gliomas using the gradient-echo echoplanar MR imaging technique. We also evaluated the usefulness of rCBV maps for grading gliomas. SUBJECTS AND METHODS: We examined 30 patients with histologically verified gliomas. Gliomas were classified as glioblastoma, anaplastic glioma with enhancement, anaplastic glioma without enhancement, and low-grade glioma. The maximum rCBV ratio of each glioma was compared with both histologic and angiographic vascularities, and the relationship between the maximum rCBV ratios and each type of glioma was established. RESULTS: The maximum rCBV ratios of the gliomas significantly correlated with both histologic and angiographic vascularities (p < .001). Mean values and SDs of maximum rCBV ratios of each type of tumor were 7.32+/-4.39 for glioblastomas, 5.84+/-1.82 for anaplastic gliomas with enhancement, 1.53+/-0.75 for anaplastic gliomas without enhancement, and 1.26+/-0.55 for low-grade gliomas. The maximum rCBV ratios of the glioblastomas were significantly higher than those of the anaplastic gliomas without enhancement (p = .002) and the low-grade gliomas (p < .001). The maximum rCBV ratios of the anaplastic gliomas with enhancement were higher than those of the anaplastic gliomas without enhancement and the low-grade gliomas, but the differences were not statistically significant (p = .08 and p = .03, respectively). CONCLUSION: The results of perfusion-sensitive MR imaging with gradient-echo echoplanar technique correlated with both histologic and angiographic vascularities.

Adolescent↗
PubMed1998

The phosphodiesterase inhibitors pentoxifylline and rolipram prevent diabetes in NOD mice.

Interleukin (IL)-12, interferon (IFN)-gamma, and other inflammatory cytokines play an important role in the pathogenesis of autoimmune insulitis and diabetes in NOD mice, and inhibition of these cytokines is likely to be beneficial. In this study, we found that Pentoxifylline (PTX) and Rolipram (phosphodiesterase [PDE] inhibitors that induce increased intracellular cAMP) can block inflammatory cytokine production. Inhibition of IL-12 and IFN-gamma secretion was demonstrated in macrophages activated with lipopolysaccharide or T-cells stimulated through the CD3/T-cell receptor complex, respectively. Moreover, strong inhibition of IL-12 was demonstrated in vivo in superantigen-immunized mice. Rolipram was inhibitory at concentrations as low as 10(-8) to 10(-7) mol/l, and on a molar basis, it was 100-fold more effective than PTX. Tumor necrosis factor-alpha was also inhibited, but IL-4 was less sensitive to suppression. In NOD mice, both PTX and Rolipram reduced the severity of insulitis and prevented diabetes, with or without cyclophosphamide administration (which precipitates onset of disease). This protection of NOD mice was still apparent over 10 weeks after withdrawal of the drug treatment. It appears that blocking the activity of type IV PDE is sufficient to mediate the effects reported in this study, since Rolipram inhibits only this isoform, unlike PTX (a general inhibitor). PTX and Rolipram may be effective in the treatment of autoimmune diabetes or other conditions characterized by excessive production of inflammatory cytokines.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1998

[Immunoprotection in guinea pigs using DNA recombinant plasmid rpDJt and expressed protein P68 in L. interrogans serovar lai].

Immunoprotection against the infection by Leptospira interrogans serogroup Icterohemorrhagiae serovar lai strain 017 was demonstrated in guinea pigs vaccinated with DNA recombinant plasmid rpDJt and expressed protein P68 derived from genomic library of Leptospira strain 017. Thirty days after active immunization, each group received intraperitoneally (1/2 dose) and subcutaneously (1/2 dose) inoculum of L. interrogans serovar lai stain 017; cultures were adjusted to 5 x 10(8) cells/ml. All guinea pigs were observed for 10 days after challenge. Survival (%) of P68 group was 100(7/7); P23 group was 75(3/4); group rpDJt was 77(10/13); group lack recombinant (control) pT7-7 was 25 (3/12), and group with whole-cell inactivated vaccine was 93(13/14). Although the protective antigen in the leptospires has yet to be determined, it is evident that expressed protein P68 conferred a high degree of immunoprotection in guinea pigs.

Animals↗
PubMed1998

[Antiandrogen treatment for nude mice model with ectopic transplanted human HCC].

OBJECTIVE: To investigate the effect of antiandrogen on hepatocellular carcinoma (HCC). METHODS: Nude mice model with orthotopic transplanted human HCC was constructed and the androgen receptor (AR) in tumor and surrounding liver tissue was assayed dynamically. Nude mice with ectopic transplanted HCC were treated with flutamide (blocker of AR) at two different dosages (Group F1, F2), normal saline(Group C), and anticancer drug(Group M). The effect of treatments was compared among the groups. RESULTS: The quantity of AR in nucleus and cytoplasm in tumor and tumor-surrounding tissue decreased with the increasing size of tumor in proper order. AR in tumor was significantly less in F1 and F2 groups than in other groups. The tumor weight of group F1, F2 and C had no significant difference (1.36 +/- 0.82 g, 2.66 +/- 1.40 g, 1.66 +/- 0.79 g, respectively), but was significantly higher than that of group M. CONCLUSION: Androgen may play a role at the initial stage of hepatocarcinogenesis, and antiandrogen therapy may be ineffective in the established tumor.

Androgen Antagonists↗
PubMed1998

[Hepatectomy for hepatolithiasis treatment of 354 cases].

OBJECTIVE: To evaluate the effect of hepatectomy for hepatolithiasis. METHOD: 354 patients with hepatolithiasis underwent hepatectomy in the past 10 years. The results were analysed retrospectively, including clinical findings, distribution of stones, patterns of operation, postoperative complications, and residual stones. The clinical data of the patients before 1990 were compared with those thereafter. RESULT: Left hepatolithiasis was the most common form (323 patients). Left lateral lobectomy and left hepatectomy were most commonly employed (91.2%). 166 of the patients underwent concurrent cholangiojejunostomy. 13.8% patients had residual stones, and postoperative complications occurred in 60 patients, including 4 deaths. Few patients were reoperated on and the incidence of residual stones was lower after 1990. 88% the patients showed excellent or good result. CONCLUSION: Hepatectomy is a procedure for the management of hepatolithiasis, but still requires combined plasty of stenotic intrahepatic bile ducts and cholangiojejunostomy to reduce the incidence of residual stones and recurrence.

Adolescent↗
PubMed1998

[Dynamic change of androgen-receptor in tumor and surrounding liver tissue of nude mice model with transplanted human HCC].

OBJECTIVE: To research into the law of androgen-receptor (AR) dynamic change in developing course of human HCC. METHOD: Dynamic measurement of AR in tumor and peritumorous tissue was performed in nude mice model with orthotopic transplanted human HCC. RESULT: Tumor nodules were present in 90% nude mice 4 weeks after transplantation, tumor necrosis was found in the 10th week, and remarkable necrosis occurred in the 12th week. The quantity of AR in tumor and peritumorous tissue was highest in the early stage of tumor (102.32 +/- 21.42 fmol/mg protein and 72.45 +/- 10.11 fmol/mg protein respectively), and then decreased progressively with time to the 10th week (40.98 +/- 21.11 fmol/mg protein and 53.39 +/- 7.01 fmol/mg protein respectively). The difference in AR between each two weeks was significant. CONCLUSION: Androgen promotes the development of tumor because of existence of AR, and its action may decline after establishment of tumor. Therefore, antiandrogen treatment may be ineffective after establishment of tumor.

Animals↗