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Biomedical subjects

Li Sheng

Publications and source records attributed to Li Sheng.

31 records · Page 2Linked to original sources

Clinical and biologic analysis of pancreatoblastoma.

Since the first description of pancreatoblastoma as a malignant pancreatic tumor of childhood in 1957, approximately 200 cases have been reported. We describe an 18-year-old boy who presented with pain and jaundice and was found to have an abdominal mass. The patient initially presented with abdominal pain. During laparotomy, a 10 x 8 x 8-cm3 tumor was discovered in the pancreatic body and tail, and with 3 cystic masses, 15, 10, and 8 cm in diameter, respectively, involving the right lobe of the liver. Pathologic examination of the resected tumor revealed findings characteristic of pancreatoblastoma. The tumor formed acinar and glandular structures and solid areas and contained many "squamoid corpuscles," a defining feature of pancreatoblastoma. In spite of adjuvant chemotherapy with Adriamycin and gemcitabine, the patient returned 11 months later with several large hepatic masses, invading the pancreatic head and enlarged tracheobronchial lymph nodes. Radiotherapy, transcatheter arterial embolization therapy, and chemotherapy were performed. Unfortunately, the patient died 26 months later from disseminated tumor progression. A review of the literature reveals that pancreatoblastoma in childhood must be considered malignant but usually has a favorable prognosis in contrast to pancreatic neoplasms in adult patients. Biologic study will investigate the molecular biology of this rare tumor. The biology may help define prognosis and therapy for this kind of tumor.

Adolescent↗

[Subcellular localization and tissues expression profile of hGPCRc: an orphan G protein-coupled receptor].

As a member of orphan G protein-coupled receptors (oGPCRs), hGPCRc was cloned from human colon tissue and analyzed by bioinformatic softwares. It was showed that the corresponding amino acids of hGPCRc formed seven-transmembrane domains as the key characteristic of GPCRs. Then, the recombinant GFP-hGPCRc was constructed by fussing hGPCRc into pEGFP-N1 carrying green fluorescent protein (GFP) gene, and CHO-K1 cells were subsequently transfected with the GFP-hGPCRc or pEGFP-N1. The green fluorescence protein expression in the two different transfected cells was observed under the laser scanning confocal microscopy (LSCM). It was showed that green fluorescence protein was distributed in the whole bodies of the cells transfected with pEGFP-N1, but mainly distributed on the plasma membrane and cytoplasm membrane transfected with GFP-hGPCRc. Thus, the localization on the membrane of hGPCRc was accorded with the predication by bioinformatic analysis. The expression analysis of hGPCRc by RT-PCR indicated that hGPCRc was abundantly expressed in heart, kidney, cerebel and colon etc., but absent in liver, cerebra, small intestine and muscle etc. The expressing profile of hGPCRc could provide some useful clues to understanding its effects on embryonic development and physiological functions.

Amino Acid Sequence↗

[Preliminary study on anti-tumor function of resveratrol and its immunological mechanism].

AIM: To explore the immunological mechanism of the anti-tumor function of resveratrol (Res) through in vitro or vivo experiments. METHODS: The tumor cell growth repression rate was measured by MTT colorimetry. Flow cytometry was used to analyze the cell cycle of Hep2 cells (laryngeal squamous cancer cell line). The immune function and cytokine levels in the serum of the tumor-bearing mice were determined by MTT colorimetry, hemolysis spectrophotography, improved Mayer's method and ELISA. RESULTS: Res inhibited the tumor cell growth and enhanced the apoptosis of tumor cells in time-concentration-dependent manners showing the phenomenon of obvious G(0)/G(1) blocking and apoptotic peak. The maximal tumor inhibition rate came up to 42.76%. Furthermore, Res improved function of T, B lymphocytes, killing activity of NK cells, release of antibodies, and the total complement activity in serum. It also increased contents of IL-2 and TGF-beta1 but reduced that of IL-8 and VEGF. CONCLUSION: Res can not only affect tumor cells directly but also exert anti-tumor efficiency through reinforcing cell-mediated, humoral immune response and accommodating lymphocytes to secrete cytokines.

Animals↗

[Design of multifocal visual electrophysiology examining system based on fast m-transform].

The multifocal visual electrophysiology is an objective and non-invasive method to examine visual function. It can examine many tiny areas of retina at the same time and have a particular advantage in diagnosing the early diseases of ocular fundus. This paper introduces the design of multifocal visual electrophysiology examining system. The system uses multidisplay technology exclusively owned by Windows 98 or above operating system to control graphics stimulator which generates specified hexagonal array. The white or black transition of each hexagon controlled by a binary m-sequence stimulates corresponding area of retina. The specified Burian-Allen electrode is used to extract the mixed signal originated from many areas of retina. The signal is amplified and A/D transformed. The computer separates the mixed signal through fast m-transform and gets the response of each area of retina. The fast m-transform is a fast computation of cross-correlations with binary m-sequences and can reduce cross-correlation computation to a single Fast Walsh Transform. So a lot of time can be saved.

Electrophysiology↗

[Research on resveratrol's effects on suppressing growth and inducing apoptosis of GBC cells].

OBJECTIVE: To explore the contribution of resveratrol (Res) to the proliferation and apoptosis of gallbladder carcinoma (GBC) cell line as well as fibroblast 3T3 cell line in vitro. METHODS: The tumor cell growth repressing rate was measured by the MTT method,and flow cytometry was used to analyse cell cycle. The gene expression of bcl-2 c-myc p53 were examined by SABC. RESULTS: Res obviously suppressed the proliferation (P <0. 01) in concentration and time dependent manner, it's tiptop was 54%. Res could induce apoptosis of tumor cells. The maximum apoptosis rate of tumor was 30. 52%, experiment group compared with comparison group Gl's cells rised from 34. 88% to 55.47 +/- 3. 95%, S's cells reduced 8.41 - 17.54%, which showed obvious phenomenon of G0/G1 blocking. The GBC cell's bcl-2, c-myc gene reduced expression,while p53 gene increased expression. CONCLUSION: The results of this study confirm the ability of Res to suppress the proliferation of gallbladder carcinoma (GBC) cell with a typical apoptotic feature in vitro. Therefore, Res may be considered as a possible treatment strategy for gallbladder carcinoma.

Animals↗

[Atorvastatin upregulates the expression of PPAR alpha/gamma and inhibits the hypertrophy of cardiac myocytes in vitro].

OBJECTIVE: To investigate the effects of atorvastatin on angiotensin II (Ang II)-induced hypertrophy of cardiac myocytes (MC) and the changes of mRNA expression of peroxisome proliferators-activated receptor alpha, gamma (PPAR alpha, gamma) subtypes in vitro. METHODS: Hypertrophy in neonatal rat MC was established with Ang II and treated with atorvastatin. The surface area of MC was analyzed by the aid of NIH Image J software, and the synthetic rate of protein in MC was detected by (3)H-leucine incorporation. mRNA expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), matrix metalloproteinase (MMP) 9, MMP2, interleukin1beta (IL-1beta) and PPARalpha, gamma was measured by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Changes of MC were detected induced by Ang II, including increases in surface area, mRNA expression of ANP, BNP, MMP9, MMP2 and IL-1beta, and (3)H-leucine incorporation, as well as a decrease in mRNA expression of PPARalpha, gamma. Treatment with atorvastatin inhibited the changes above in a dose-dependent manner, but no change was found in treated with DMSO. CONCLUSION: Atorvastatin inhibits cardiac hypertrophy in vitro. It is suggested that atorvastatin has a potential role in the prevention and treatment of cardiac diseases such as cardiac hypertrophy, and PPAR alpha and gamma maybe involved in this process.

Angiotensin II↗

Chlorobis[N-ethoxycarbonyl-N'-(p-methoxyphenyl)thiourea-kappaS]copper(I).

The title copper(I) complex, [CuCl(C(11)H(14)N(2)O(3)S)(2)], was synthesized by the redox reaction of cupric chloride with the corresponding thiourea derivative as reducing agent. The Cu(I) coordination environment is trigonal planar, involving two S atoms and one Cl atom. The presence of intramolecular hydrogen bonds leads to the formation of a cis conformation and promotes the stability of the complex.

Journal Article↗

Ab initio direct dynamics studies on the reaction of H atom with CH3CH2Cl.

The multiple channel reaction H + CH(3)CH(2)Cl --> products has been studied by the ab initio direct dynamics method. The potential energy surface information is calculated at the MP2/6-311G(d,p) level of theory. The energies along the minimum energy path are further improved by single-point energy calculations at the PMP4(SDTQ)/6-311+G(3df,2p) level of theory. For the reaction, four reaction channels (one chlorine abstraction, one alpha-hydrogen abstraction, and two beta-hydrogen abstractions) have been identified. The rate constants for each reaction channel are calculated by using canonical variational transition state theory incorporating the small-curvature tunneling correction in the temperature range 298-5000 K. The total rate constants, which are calculated from the sum of the individual rate constants, are in good agreement with the experimental data. The calculated temperature dependence of the branching fractions indicates that for the title reaction, H-abstraction reaction is the major reaction channel in the whole temperature range 298-5000 K.

Journal Article↗

Theoretical study on the rate constants for the C2H5 + HBr --> C2H6 + Br reaction.

The reaction C(2)H(5) + HBr --> C(2)H(6) + Br has been theoretically studied over the temperature range from 200 to 1400 K. The electronic structure information is calculated at the BHLYP/6-311+G(d,p) and QCISD/6-31+G(d) levels. With the aid of intrinsic reaction coordinate theory, the minimum energy paths (MEPs) are obtained at the both levels, and the energies along the MEP are further refined by performing the single-point calculations at the PMP4(SDTQ)/6-311+G(3df,2p)//BHLYP and QCISD(T)/6-311++G(2df,2pd)//QCISD levels. The calculated ICVT/SCT rate constants are in good agreement with available experimental values, and the calculate results further indicate that the C(2)H(5) + HBr reaction has negative temperature dependence at T < 850 K, but clearly shows positive temperature dependence at T > 850 K. The current work predicts that the kinetic isotope effect for the title reaction is inverse in the temperature range from 200 to 482 K, i.e., k(HBr)/k(DBr) < 1.

Journal Article↗

[Study on relationship among thyroid hormone relativity and Syndrome Differentiation-types of TCM in patients with congestive heart failure].

OBJECTIVE: To study the relationship between the TCM Syndrome Differentiation-types of congestive heart failure (CHF) and thyroid hormones, including triiodothyronine (T3), thyroxine (T4) and thyroid stimulating hormone (TSH), and atrial natriuretic peptide (ANP), as well as cardiac function parameters, including left ventricular ejection fraction (LVEF), mean velocity of circumferentid fiber shortening (mVcf) and A peak/E peak (A/E). METHODS: One hundred patients with CHF were divided into 4 Syndrome Differentiation-type groups, their cardiac function parameters, ANP and thyroid hormones were determined and compared with those in the 23 subjects in the control group. RESULTS: In CHF patients with edema and blood stasis Syndrome type, the level of plasma ANP was significantly higher than that in the control group (P < 0.05); level of T3 was significantly lower than that in the control group and in CHF patients of other three (Xin-qi deficiency, Yin-deficiency and blood stasis) Syndrome groups (P < 0.01, P < 0.01, P < 0.05 and P < 0.01); levels of LVEF and mVcf were significantly lower than those in the other three Syndrome groups (all P < 0.01). Level of T4 in other three Syndrome groups significantly increased than that in the edema and blood stasis Syndrome type. A/E value showed a higher level in patients of all TCM type than that in the control (P < 0.01). Correlation analysis showed that T3 was positively correlated with LVEF and T4 (r = 0.200, P < 0.05, and r = 0.293, P < 0.01), and negatively correlated with ANP (r = -0.263, P < 0.01); T4 was negatively correlated with A/E (r = -0.226, P < 0.05). CONCLUSION: The lowering of T3 and T4 and increasing of ANP may be one of the important reasons for lowering of LVEF in CHF patients with edema and blood stasis Syndrome-type. The decrease of T4 may be one of the important reasons for elevation of A/E and aggravation of left ventricular diastolic dysfunction in CHF patients of all the 4 TCM Syndrome-types.

Adult↗

DFT and ab initio direct dynamics studies on the hydrogen abstraction reactions of chlorine atoms with CH(4-n)F(n) (n = 1-3).

A direct dynamics study is carried out for the hydrogen abstraction reactions Cl + CH(4-n)F(n) (n = 1-3) in the temperature range of 200-1,000 K. The minimum energy paths (MEPs) of these reactions are calculated at the BH&H-LYP/6-311G(d,p) level, and the energies along the MEPs are further refined at the QCISD(T)/6-311+G(2df,2p) and QCISD(T)/6-311+G(d,p) (single-point) level. The rate constants obtained by using the improved canonical variational transition state theory incorporating small-curvature tunneling correction (ICVT/SCT) are in good agreement with the available experimental results. It is shown that the vibrational adiabatic potential energy curves for these reactions have two barriers, a situation similar to the analogous reactions CH(3)X+Cl (X=Cl, Br). The theoretical results show that for the title reactions the variational effect should not be neglected over the whole considered temperature range, while the small-curvature tunneling effect is only important in the lower temperature range. The effects of fluorine substitution on the rate of this kind of reactions are also examined.

Journal Article↗

Comprehensive two dimensional separation based on coupling micellar electrokinetic chromatography with capillary isoelectric focusing.

Concentrating properties of the Capillary Isoelectric Focusing (CIEF) system with continuous whole-column-imaging detection were investigated for application as a second dimension in a comprehensive two-dimensional (2D) separation process. The concentration/separation/detection was completed within 4 min in a 300 microm inner diameter capillary. As the key to the successful coupling of CIEF to a first dimension separation, a novel interface was developed. A 10-port valve with two conditioning loops was used to perform both comprehensive collection and dialysis desalting of the first dimensional effluent, and as an interface coupling Micellar Electrokinetic Chromatography (MEKC) to CIEF. In the loop, salt and other unwanted first dimension effluent components were eliminated by dialysis and carrier ampholytes (CAs) were added. Peak broadening during the dialysis did not have significant impact on the CIEF separation because of its concentrating effect. Protein digests were first separated by MEKC followed by isoelectric point (pI) using whole-column-imaged CIEF. The dialysis interface allows general coupling of the whole-column-imaged CIEF to microscale separations.

Animals↗

Prosodic and lexical-syntactic aspects of the therapeutic register.

The current study examined features of speech addressed to younger versus older and impaired versus normal listeners and explored factors that might motivate speech modification in the therapeutic register. Ten speech-language clinicians in training were engaged in a simulated storytelling task and produced narrations to four imaginary listener groups. Results revealed that clinicians modified their speech at multiple levels according to both the age and the diagnostic status of their listeners. As a group, the clinicians demonstrated decreased speaking rate, elongation of pauses, and use of shorter and less complex sentences when speaking to young children and individuals with language impairments. Despite these group trends there was notable individual variability between clinicians. Findings from this constrained experimental context may be extended to real life clinician-client interactions and have implications for therapeutic success.

Acoustics↗