Biomedical subjects

L Shao

Publications and source records attributed to L Shao.

At least 73 records · Page 4Linked to original sources

PubMed1997

Semi-automated radioassay for determination of dihydropyrimidine dehydrogenase (DPD) activity. Screening cancer patients for DPD deficiency, a condition associated with 5-fluorouracil toxicity.

Dihydropyrimidine dehydrogenase (DPD) catalyzes the reduction of the naturally occurring pyrimidines, uracil and thymine, and the fluoropyrimidine anticancer drug, 5-fluorouracil (FUra) to 5,6-dihydropyrimidines. Previous studies have demonstrated that cancer patients who are DPD deficient exhibit severe toxicity (including death) following treatment with FUra. To date, the direct measurement of DPD enzyme activity has been the only reliable method to identify DPD deficient cancer patients. We now report a semi-automated radioassay for measuring DPD activity in human peripheral lymphocytes. Following incubation of lymphocyte cytosol (at a fixed protein concentration of 200 micrograms) with [6-14C]FUra at timepoints ranging from 0 to 30 min, samples are ethanol precipitated, filtered and analyzed by HPLC. Determination of radioactivity is accomplished using an in-line flow scintillation analyzer with automatic quantitation of peaks. This method provides the first specific assay for DPD enzyme activity which is rapid, reproducible and sensitive enough to be used in the routine screening of cancer patients for DPD deficiency prior to treatment with FUra.

Antimetabolites, Antineoplastic↗

PubMed1997

[Generation of suppressive protein after heavy physical stress in athletes].

Our previous work showed that under the condition of restraint stress and the control of central nervous system, a suppressive protein (neuroimmune protein, NIP) was generated in peripheral lymph tissue and released into the blood stream, which acts as an immune suppressor. In the present study the serum from the athletes performed a heavy athletic training for 18 days was also able to suppress the lymphocyte proliferation of normal mice. The molecular weight at the suppressive factor in athlete serum determined by gel filtration HPLC was similar to that in mice and rats. In vitro experiment, the normal human lymphocytes were incubated with the serum from restraint stressed rats for 12 h and then the extract of human lymphocyte was made for testing the effect on normal lymphocyte proliferation. The result showed that it suppressed normal mouse lymphocyte proliferation. This result was similar to our previous experiment by using normal mouse lymphocyte incubated with the rat serum treated with restraint stress. It was also found that the serum and the extract of lymph node from restraint stressed mice suppressed human lymphocyte proliferation induced by PHA. The results suggest that suppressive protein induced by stress in mice and rats could also be induced in human beings and there is no distinct species specificity among them.

Adult↗

PubMed1997

Three-dimensional imaging characteristics of the HEAD PENN-PET scanner.

UNLABELLED: A volume-imaging PET scanner, without interplane septa, for brain imaging has been designed and built to achieve high performance, specifically in spatial resolution and sensitivity. The scanner is unique in its use of a single annular crystal of Nal(Tl), which allows a field of view (FOV) of 25.6 cm in both the transverse and axial directions. Data are reconstructed into an image matrix of 128(3) with (2 mm)3 voxels, using three-dimensional image reconstruction algorithms. METHODS: Point-source measurements are performed to determine spatial resolution over the scanner FOV, and cylindrical phantom distributions are used to determine the sensitivity, scatter fraction and counting rate performance of the system. A three-dimensional brain phantom and 18F-FDG patient studies are used to evaluate image quality with three-dimensional reconstruction algorithms. RESULTS: The system spatial resolution is measured to be 3.5 mm in both the transverse and axial directions, in the center of the FOV. The true sensitivity, using the standard NEMA phantom (6 liter), is 660 kcps/microCi/ml, after subtracting a scatter fraction of 34%. Due to deadtime effects, we measure a peak true counting rate, after scatter and randoms subtraction, of 100 kcps at 0.7 mCi for a smaller brain-sized (1.1 liter) phantom, and 70 kcps for a head-sized (2.5 liter) phantom at the same activity. A typical 18F-FDG clinical brain study requires only 2 mCi to achieve high statistics (100 million true events) with a scan time of 30 min. CONCLUSION: The HEAD PENN-PET scanner is based on a cost-effective design using Nal(Tl) and has been shown to achieve high performance for brain studies and pediatric whole-body studies. As a full-time three-dimensional imaging scanner with a very large axial acceptance angle, high sensitivity is achieved. The system becomes counting-rate limited as the activity is increased, but we achieve high image quality with a small injected dose. This is a significant advantage for clinical imaging, particularly for pediatric patients.

Brain↗

PubMed1997

Maximal aerobic capacity and its relationship with physical growth in Chinese children.

Maximal aerobic capacity and its relationship to physical growth in 463 Chinese children and adolescents aged 10-19 is reported. Results show that VO2max, VO2max/height and VO2max/HRmax positively relate to measures of physical growth such as height, weight and lean body mass (LBM). Correlation of VO2max/weight with physical growth variables is high and positive in boys and low and negative in girls. The sample is divided to two groups on each variable: well-developed and relatively poorly-developed according to height, weight and LBM. SDS values of VO2max, VO2max/height and VO2max/HRmax are higher in the first group than in the second group. In contrast, SDS values of VO2max/weight and VO2max/LBM are greater in second group. The similarity of results between SDS values with correlation analysis suggest that weight and LBM are probably the decisive factors that influence VO2max.

Adolescent↗

PubMed1997

Detection of hepatitis G virus RNA in patients with hepatitis B, hepatitis C, and non-A-E hepatitis by RT-PCR using multiple primer sets.

Hepatitis G virus(HGV)/GB virus C(GBV-C) is a newly identified virus associated with human hepatitis. The preliminary prevalence studies of HGV infection in Japan were entirely based on the detection of HGV RNA by RT-PCR. However, the selection of the different primer sets in such assay may influence sensitivity of the test because of the extensive genetic heterogeneity of HGV, and influence the estimation of the prevalence of HGV. To address this potential problem, we designed two primer sets from well conserved domains in the 5'NC and NS5 regions of HGV genome, and tested them together with the NS3-derived primer set in RT-PCR for their ability to detect HGV RNA in serial dilution of synthetic viral RNA templates. Subsequently, we used these three primer sets to detect HGV RNA in the sera of 371 Japanese patients with hepatitis B, hepatitis C, and non-A-E hepatitis. The results indicated that the primer set derived from the 5'NC region appeared to be most effective in detecting HGV RNA. The results also showed that only two out of the 126 patients (1.6%) with non-A-E hepatitis were positive for HGV RNA although the RNA were detected more frequently in patients with hepatitis B (2/38; 5.3%) and hepatitis C (17/207; 8.2%), suggesting that HGV is not a common causative agent for non-A-E hepatitis in Japan.

Base Sequence↗

PubMed1997

[A prevalence study on risk factors of cardiovascular disease during childhood].

A small size of sample for risk factors of cardiovascular disease, such as blood pressure, plasma lipids profile, obesity, dietary status, and family history of cardiovascular disease, etc. were studied in children aged eight to eleven years. Results showed that prevalence of hypertension, systolic blood pressure > 16.0 kPa (120 mmHg) or/and diastolic blood pressure > 10.7 kPa (80 mmHg), in them was 7.2 percent, blood lipid level in 21.9 percent of the children exceeded the recommended criteria of dietary intervention, and prevalence of simple obesity was 11.7 percent. The most prominent problem in dietary status was high cholesterol intake, with a daily intake of 483.4 mg in average, and 72 percent of the children exceeded 300 mg daily, as compared with previous data, and they exposure to higher level of risk factors for cardiovascular disease. It suggests that it is necessary to strengthen surveillance for risk factors of cardiovascular disease and intervention.

Cardiovascular Diseases↗

PubMed1997

Presence of methylthioadenosine phosphorylase (MTAP) in hematopoietic stem/progenitor cells: its therapeutic implication for MTAP (-) malignancies.

Methylthioadenosine phosphorylase (MTAP) is important for the salvage of adenine and methionine. Recently, we found frequent deletion of MTAP in T-cell acute lymphoblastic leukemia (T-ALL) patients both at diagnosis and at relapse (A. Batova et al., Blood, 88: 3083-3090, 1996). In addition, MTAP deficiency has been reported in other cancers. Thus, MTAP deficiency in cancer may offer opportunities for developing selective therapy, which would spare normal cells. It is therefore important to document the presence of MTAP activity in hematopoietic stem/progenitor cells. Our approach was to investigate whether hematopoietic stem/progenitor cells can be rescued from the cytotoxicity of an AMP synthesis inhibitor, L-alanosine, by 5'-deoxyadenosine, a process that requires MTAP. Erythroid burst-forming unit, granulocyte/monocyte colony-forming unit, or granulocyte/erythrocyte/macrophage/megakaryocyte colony-forming unit progenitors and the primitive high proliferative potential colony-forming cells in the purified CD34(+) cells were cultured in horse serum-containing medium, and their colony growth was found to be suppressed by incubation with 5 microM or greater concentrations of L-alanosine. However, in the presence of 5-10 microM of 5'-deoxyadenosine, colony formation of hematopoietic stem/primitive progenitors was restored. On the other hand, 5'-deoxy-5'-methylthioadenosine, the endogenous substrate of MTAP, was toxic to hematopoietic stem/progenitors (ID50 < 1 microM), presumably due to inhibition of methylation reactions or polyamine synthesis. We also compared the effects of L-alanosine and 5'-deoxyadenosine on MTAP (+) and MTAP (-) T-ALL cell lines. Treatment of MTAP (+) Molt 4 and MTAP (-) CEM cell lines with L-alanosine in the presence of 5'-deoxyadenosine resulted in killing of MTAP (-), but not MTAP (+) cells. Therefore, our findings demonstrate the presence of MTAP in human hematopoietic stem/progenitor cells and support the possibility of targeting MTAP in the design of an enzyme-selective therapy for T-ALL and other MTAP-deficient malignancies.

Alanine↗

PubMed1996

Regulation of rat interstitial collagenase gene expression in growth cartilage and chondrocytes by vitamin D3, interleukin-1 beta, and okadaic acid.

The interstitial collagenase produced by the rat growth plate chondrocytes is the homologue of the human collagenase-3, or matrix metalloproteinase-13. This enzyme is responsible for the loss of collagen during hypertrophy of chondrocytes and for the degradation of transverse septa in long bone growth. Rachitic rats (42 days, male Sprague-Dawley) had an 8-fold higher level of collagenase mRNA in the hypertrophic versus proliferative zone of growth plate cartilage. Intramuscular injection of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3; 1.0 micrograms/kg body weight) in rachitic rats increased collagenase mRNA another 1.5-fold in the hypertrophic zone. The regulation of collagenase gene by 1,25-(OH)2D3 and interleukin (IL)-1 beta in cultured proliferative chondrocytes was studied by means of steady-state mRNA and half-life determination of mRNA using the transcriptional inhibitor actinomycin D, and nuclear run-on transcription analyses. Treatment of cells with 1,25-(OH)2D3 (10(-6) M) and IL-1 beta (2 ng/ml) increased collagenase mRNA 8- and 13-fold, respectively. Additionally, the collagenase mRNA half-life was increased by 1,25-(OH)2D3 and IL-1 beta. In the presence of a protein kinase C inhibitor, staurosporine, 1,25-(OH)2 D3 induction of collagenase mRNA was blocked. Here the addition of phorbol 12-myrisate 13-acetate (PMA) to activate protein kinase C increased collagenase mRNA 10-fold. However, in the presence of staurosporine (50 nM), PMA induction was blocked, whereas IL-1 beta was not. IL-1 beta is known to activate several phosphorylation pathways. Okadaic acid (500 nM), a protein phosphatase inhibitor, increased the relative collagenase mRNA abundance 10-fold. The rate of the rat collagenase gene transcription in nuclei was increased with 1,25-(OH)2D3, IL-1 beta and okadaic acid. In separate experiments, the collagenase promoter was ligated to a reporter plasmid and the plasmid was transfected into chondrocytes. The results showed that 1,25-(OH)2D3, IL-1 beta, and PMA increased reporter activity 2.5-, 2.8-, and 3.27-fold, respectively. Thus, there are multiple nuclear and cytoplasmic mechanisms by which cartilage modulators regulate rat interstitial collagenase gene expression.

Actins↗

PubMed1996

Sequence of hepatitis G virus genome isolated from a Japanese patient with non-A-E-hepatitis: amplification and cloning by long reverse transcription-PCR.

The nucleotide sequence of hepatitis G virus (HGV) genome was determined by analysis of cDNA clones obtained by long reverse transcription-polymerase chain reaction (long RT PCR) and 5'- and 3'-rapid amplification of cDNA ends (RACE) from a Japanese patient (Iw) with non A-E hepatitis. The HGV-Iw genome, consisting of 9375 nucleotides, contains a long open reading frame encoding 2873 amino acid residues. Comparison of HGV-Iw with two American isolates of HGV and one African isolate of GB virus C (GBV-C) indicates that although the nucleotide sequences of these isolates were considerably divergent (86.2% to 93.3%), the deduced amino acid sequences shared an extremely high degree of identity (96.1% to 100%). It was also found that HGV-Iw was more closely related to the HGV isolates from USA than to the GBV-C isolate from Africa.

Cloning, Molecular↗

PubMed1996

Intracellular localization of the herpes simplex virus type-1 origin binding protein, UL9.

UL9 is the origin binding protein of herpes simplex virus type-1 (HSV-1). A UL9-specific monoclonal antibody (17B) whose epitope maps to the N-terminal 33 amino acids was used to study the localization of UL9 in infected and transfected cells. We demonstrate the colocalization of UL9 and the HSV-1 single-strand DNA binding protein (ICP8 or UL29) in replication compartments, sites of viral DNA synthesis. On the other hand, UL9 does not completely colocalize with ICP8 in prereplicative sites, structures observed under conditions that inhibit viral DNA polymerase. Cells transfected with various deletion or pyruvate kinase fusion constructs were analyzed by indirect immunofluorescence assay to define the nuclear localization signal (NLS) of UL9. Deletion analysis showed that the region required for nuclear localization lies within the C-terminal DNA binding domian (amino acids 535-851). Various regions of UL9 were tested in fusion constructs for their ability to direct the normally cytoplasmic chicken pyruvate kinase protein to the nucleus. A fusion construct containing the carboxy-terminal 107 residues (amino acids 745-851) localized efficiently to the nucleus, whereas a fusion construct containing the N-terminal 660 amino acids of UL9 was unable to do so. Mutations designed to alter a potential NLS sequence (793-KREFAGARFKLR-804) within the C-terminal 107 residues result in a mutant UL9 protein which falls to localize efficiently to the nucleus. These results suggest that the major NLS of UL9 maps within the C-terminal 107 amino acids.

Animals↗

PubMed1996

The product of a 1.9-kb mRNA which overlaps the HSV-1 alkaline nuclease gene (UL12) cannot relieve the growth defects of a null mutant.

Alkaline nuclease, a relatively abundant viral phosphoprotein in herpes simplex virus type 1 (HSV-1)- or HSV-2-infected cells, is encoded by a 2.3-kb mRNA (R. H. Costa, K. G. Draper, L. Banks, K. L. Powell, G. Cohen, R. Eisenberg, and E. K. Wagner, 1983. J. Virol. 48, 591-603). This mRNA is a member of a family of five unspliced 3'-coterminal messages. Costa et al. proposed that another member of this family of mRNAs (1.9-kb) may encode an N-terminally truncated protein which shares its carboxy-terminus with the alkaline nuclease protein. We previously described the isolation of AN-1, a deletion/insertion mutant of the alkaline nuclease gene (S. K. Weller, R. M. Seghatoleslami, L. Shao, D. Rowse, and E. P. Carmichael, 1990. J. Gen. Virol. 71, 2941-2952). The deletion in AN-1 would be predicted to abolish gene products of both the 2.3- and the 1.9-kb mRNAs. To investigate whether the putative truncated version of alkaline nuclease encoded by the 1.9-kb mRNA has enzymatic activity and plays a role in the viral life cycle, a viral mutant (AN-F1) was constructed which is predicted to abolish the gene product of the 2.3-kb mRNA (full-length alkaline nuclease) but leave intact the putative product of the 1.9-kb mRNA. Using a highly sensitive polyclonal antiserum raised against a bacterially expressed full-length alkaline nuclease, we observed a 60-kDa protein in KOS- and AN-F1-infected cells but not in AN-1-infected cells. This suggests that the 60-kDa protein is likely to be expressed from the 1.9-kb mRNA; the open reading frame is now designated UL12.5. Despite the presence of the 60-kDa band, AN-F1 failed to exhibit any alkaline exonuclease activity. This result suggests that the truncated polypeptide (UL12.5) is not enzymatically active, has low levels of activity, or possesses enzymatic activity which is not detected because of the low abundance of the polypeptide. AN-1 and AN-F1 are both severely restricted with respect to growth in Vero cells, as viral yields are 100- to 1000-fold lower than those of wild-type virus. We previously reported that the major defect in AN-1 is in the ability of DNA-containing capsids which form in the nucleus to mature into the cytoplasm (L. Shao, L. M. Rapp, and S. K. Weller, 1993. Virology 196, 146-162); AN-F1 exhibits the same defect. These results indicate that although the 1.9-kb mRNA encodes a 60-kDa protein presumably from the UL12.5 open reading frame, this polypeptide cannot substitute for the full-length UL12 product.

Animals↗

PubMed1996

Circular dichroism studies of the mitochondrial channel, VDAC, from Neurospora crassa.

The protein that forms the voltage-gated channel VDAC (or mitochondrial porin) has been purified from Neurospora crassa. At room temperature and pH 7, the circular dichoism (CD) spectrum of VDAC suspended in octyl beta-glucoside is similar to those of bacterial porins, consistent with a high beta-sheet content. When VDAC is reconstituted into phospholipid liposomes at pH 7, a similar CD spectrum is obtained and the liposomes are rendered permeable to sucrose. Heating VDAC in octyl beta-glucoside or in liposomes results in thermal denaturation. The CD spectrum irreversibly changes to one consistent with total loss of beta-sheet content, and VDAC-containing liposomes irreversibly lose sucrose permeability. When VDAC is suspended at room temperature in octyl beta-glucoside at pH < 5 or in sodium dodecyl sulfate at pH 7, its CD spectrum is consistent with partial loss of beta-sheet content. The sucrose permeability of VDAC-containing liposomes is decreased at low pH and restored at pH 7. Similarly, the pH-dependent changes in the CD spectrum of VDAC suspended in octyl beta-glucoside also are reversible. These results suggest that VDAC undergoes a reversible conformational change at low pH involving reduced beta-sheet content and loss of pore-forming activity.

Amino Acids↗

PubMed1996

A suppressive protein generated in peripheral lymph tissue induced by restraint stress.

The results discussed here indicate that under the conditions of restraint stress and under the control of CNS, a suppressive protein (NIP) was generated in peripheral lymph tissue and released into the blood stream, which acts as a immune suppressor. It is potentially a very important molecule that could be very important to our understanding of the interaction between CNS and immune function.

Animals↗

PubMed1996

[Clinical evaluation of cervical esophageal reconstruction after resection of thoracic esophageal carcinoma].

From Apr. 1979 to Dec. 1994, a total of 3,714 patients with thoracic esophageal carcinoma were surgically treated. As a standard operative procedure for thoracic esophageal cancer, cervical esophagogastrostomy was performed. While this operative procedure was rarely used (accounting for only 8.8% the treated cases) in early years, it has been recently carried out in the overwhelming majority of our patients (94.1%). This technic offers the advantages of resecting the lesions radically, dissecting the regional lymph nodes in both the neck and the mediastinum, reducing the incidence of postoperative complications and improving the quality of life after operation. In this paper the operative indication, approach and the surgical efficacy are discussed.

Adult↗

PubMed1996

[A comparative study of cervical and thoracic anastomoses after esophagectomy for esophageal carcinoma].

From April 1979 to December 1984, esophagectomy was performed in 552 cases of esophageal cancer of which 108 received cervical anastomosis and 444 intrathoracic anastomosis. The total postoperative complications and operative mortality rates of the two groups were very close. Leakage was significantly more frequent after cervical anastomosis, but mortality due to leakage was less frequent than that in thoracic anastomosis. The 1-, 3-, 5-, 10-year survival rates of cervical anastomosis were apparently higher than those of intrathoracic anastomosis, but the differences were not statistically significant. The 5-year survival rates of patients with the same TNM stage failed to demonstrate any significant difference between the two groups. The quality of life among the groups was satisfactory. There was no deterioration of the quality of life in cervical anastomosis. It caused less gastroesophageal reflux than did intrathoracic anastomosis. We hold that esophagectomy with cervical anastomosis and extensive lymphadenectomy is a better treatment of choice for carcinoma of the esophagus.

Adult↗

PubMed1995

PET imaging studies of dopamine D2 receptors: comparison of [18F]N-methylspiperone and the benzamide analogues [18F]MABN and [18F]MBP in baboon brain.

A series of positron emission tomography (PET) imaging studies was conducted in a baboon with the benzamide derivatives [18F]2,3-dimethoxy-N-[9-(4-fluorobenzyl)-9-azabicyclo[3.3.1]non an-3 beta-yl]benzamide ([18F]MABN) and [18F]2,3-dimethoxy-N-[1-(4-fluorobenzyl)piperidin-4-yl]be nza mide ([18F]MBP). Studies were also conducted with the butyrophenone [18F]N-methylspiperone (NMSP) for comparison. Tissue-time activity curves of [18F]MABN are similar to those of [18F]NMSP since both compounds displayed approximately the same uptake in the basal ganglia and displayed irreversible binding kinetics in vivo. However, the rapid rate of clearance from the cerebellum and high basal ganglia:cerebellum ratio of [18F]MABN indicate that this compound has a much lower amount of nonspecific binding than [18F]NMSP. [18F]MBP displayed a higher uptake in the basal ganglia relative to [18F]NMSP and [18F]MABN and exhibited reversible binding kinetics in vivo. This property of [18F]MBP is desirable since the uptake of radioactivity in D2-rich ligands is less likely to be influenced by changes in cerebral blood flow. The current data suggest that both [18F]MABN and [18F]MBP are promising ligands for studying dopamine D2 receptors with PET.

Animals↗

PubMed1995

Identification of hepatitis C virus by immunoelectron microscopy.

Sequencing of the hepatitis C virus (HCV) has provided a better understanding of the natural history, immunology, and epidemiology of this virus. However, the morphology of HCV has not been definitively characterized. In this study, through a sequence of concentration processes, virus-like particles were isolated from human serum and liver tissue, visualized by transmission electron microscopy and identified as hepatitis C virion by immunoelectron microscopy. Spherical flavi-like virus particles, approximately 70 nm in diameter, were observed in the fraction with 1.04-1.12 g ml-1 sucrose density and bound to immunogold particles with monoclonal antibodies (mAb) against hepatitis C. The nucleocapsid of the particles, which were 50 nm in diameter, appeared to be icosahedral in structure and surrounded by an envelope covered with surface projections. A 'tadpole' form of particles was also observed. The findings indicate that the low buoyant density in sucrose and the morphological features of the hepatitis C virion are consistent with the characteristics of flaviviruses and pestiviruses.

Animals↗

PubMed1995

[Effect of intracerebroventricular injection of IL-1 beta on generation of immuno-suppressive factor in lymphocytes in stressed mice].

Our previous work showed that a suppressive factor (a protein with large molecular weight) in serum was induced by restraint stress in mice and rats, which suppressed Con A induced lymphocyte proliferation. It was also found that the generation of serum suppressive factor was under control of the central nervous system. Our further study showed that intracerebroventricular (icv) injection of interleukin 1 receptor antagonist (IL-1Ra) antagonised the generation of serum suppressive factor induced by restraint stress and icv injection of interleukin-1 beta (IL-1 beta) increased the generation of the suppressive factor. Our experiment also showed that the serum suppressive factor induced by restraint stress was first made in lymph tissue and then released into blood. The present work was designed to investigate the role of IL-1 in the brain in generation of the suppressive factor in lymph node in mice. Icv injection of IL-1 beta (1 pg/mouse) was shown to significantly increase the generation of the suppressive factor in lymph node. Icv injection of IL-1Ra, however, antagonised generation of the suppressive factor. In mice without restraint stress, both the suppressive factor in serum and in lymph node were found to be induced in dose-dependent manner by icv injection of IL-1 beta. Taken together, these results suggest that IL-1 beta in brain played a very important role in generation of the suppressive factor in lymph node. The positive correlation between the suppressive action of lymph node and of serum added to the evidence that lymph tissue is probably the source of the serum suppressive factor.

Animals↗