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Biomedical subjects

Jin Liu

Publications and source records attributed to Jin Liu.

At least 73 records · Page 4Linked to original sources
PubMed2005

A pilot study of continuous transtracheal mixed venous oxygen saturation monitoring.

UNLABELLED: In this study, we investigated the feasibility and the accuracy of transtracheal mixed venous oxygen saturation (Svo(2)) monitoring. Ten patients undergoing thoracic surgery were included in this study. A single-use pediatric pulse oximetry sensor was attached to the double-lumen tube between the tracheal and bronchial cuff. After anesthesia was induced, the double-lumen tube was inserted into the trachea and adjusted to the proper position. During surgery, the pulmonary arterial blood was sampled every 3 min for 15 min to measure the Svo(2). The measurements made by the transtracheal pulmonary pulse oximeter (Sto(2)) were recorded at the same time that blood was sampled from the pulmonary artery for Svo(2) measurements. The levels of measurement agreement between the Sto(2) and the Svo(2) were analyzed using the Bland and Altman method. The mean +/- sd (range) oxygen saturation values during the data collecting period were 82.0% +/- 4.9% (72%-91%) for the Sto(2) and 82.2% +/- 5.5% (71%-91%) for the Svo(2), respectively. The linear correlation coefficient of the regression analysis between the Sto(2) and the Svo(2) was 0.934 (P < 0.05). A 95% confidence interval for absolute difference between the Sto(2) and the Svo(2) was 1.58%-2.09%. The mean +/- 2 sd difference between the Sto(2) and the Svo(2) was 0.12% +/- 3.97% on the Bland and Altman graph. We conclude that it is feasible to monitor the pulmonary artery oxygen saturation continuously by a transtracheal pulse oximetry technique and that it can be done so accurately. IMPLICATIONS: Mixed venous oxygen saturation (Svo2) is a measure of the balance between oxygen supply and consumption throughout the whole body. Svo2 can be measured invasively by inserting a pulmonary artery catheter with the associated disadvantages of cost and potential for patient injury. In this study, we investigated the feasibility of noninvasive Svo2 measurement using a transtracheal pulse oximetry technique.

Adult↗
PubMed2005

Doxapram only slightly reduces the shivering threshold in healthy volunteers.

We determined the effects of doxapram on the major autonomic thermoregulatory responses in humans. Nine healthy volunteers were studied on 2 days: control and doxapram (IV infusion to a plasma concentration of 2.4 +/- 0.8, 2.5 +/- 0.9, and 2.6 +/- 1.1 microg/mL at the sweating, vasoconstriction, and shivering thresholds, respectively). Each day, skin and core temperatures were increased to provoke sweating, then reduced to elicit peripheral vasoconstriction and shivering. We determined the sweating, vasoconstriction, and shivering thresholds with compensation for changes in skin temperature. Data were analyzed with paired t-tests and presented as mean +/- sd; P < 0.05 was considered statistically significant. Doxapram did not change the sweating (control: 37.5 degrees +/- 0.4 degrees C, doxapram: 37.3 degrees +/- 0.4 degrees C; P = 0.290) or the vasoconstriction threshold (36.8 degrees +/- 0.7 degrees C versus 36.4 degrees +/- 0.5 degrees C; P = 0.110). However, it significantly reduced the shivering threshold from 36.2 degrees +/- 0.5 degrees C to 35.7 degrees +/- 0.7 degrees C (P = 0.012). No sedation or symptoms of panic were observed on either study day. The observed reduction in the shivering threshold explains the drug's efficacy for treatment of postoperative shivering; however, a reduction of only 0.5 degrees C is unlikely to markedly facilitate induction of therapeutic hypothermia as a sole drug.

Adult↗
PubMed2005

Overexpression of cyclooxygenase-2 in gastric cancer correlates with the high abundance of vascular endothelial growth factor-C and lymphatic metastasis.

Cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF)-C are closely related with the development and metastasis of tumors. The gene expression of COX-2 and VEGF-C in gastric cancer and the correlation between them were investigated; 64 paraffin-embedded gastric cancer samples and 22 flesh gastric cancer samples were tested by using immunohistochemistry and the reverse transcription polymerase chain reaction (RT-PCR) technology, respectively. The mean expressive density of COX-2 and VEGF-C mRNA in gastric cancer, with beta-actin coamplified as an internal standard, were both significantly higher than those in non-cancerous gastric mucosa (1.363 +/- 0.351 vs 0.763 +/- 0.304, 0.972 +/- 0.331 vs 0.314 +/- 0.215, p < 0.001). The positive rates of COX-2 and VEGF-C in 64 gastric cancer samples were 72% and 64% respectively. Their expression in the lymph-node metastasis groups were higher than that of the non-lymph-node metastasis groups (p < 0.05). Moreover, there was a close correlation between COX-2 and VEGF-C expression levels (p < 0.05). The study indicates gastric tumor tissues that produce COX-2 and VEGF-C may have a higher lymphatic invasion and metastatic potential. COX-2 may participate in VEGF-C lymphangiogenic pathway and the high expression of them may play an important role in the lymphatic proliferation and spread in gastric cancer.

Adenocarcinoma↗
PubMed2005

Combination of acute preoperative plateletpheresis, cell salvage, and aprotinin minimizes blood loss and requirement during cardiac surgery.

Acute preoperative plateletpheresis (APP), cell salvage (CS) technique, and the use of aprotinin have been individually reported to be effective in reducing blood loss and blood component transfusion while improving hematological profiles in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). In this prospective randomized clinical study, the efficacy of these combined approaches on reducing blood loss and transfusion requirements was evaluated. Seventy patients undergoing primary coronary artery bypass grafting (CABG) were randomly divided into four groups: a control group (group I, n = 10) did not receive any of the previously mentioned approaches. An APP and CS group (group II, n = 20) experienced APP in which preoperative platelet-rich plasma was collected and reinfused after reversal of heparin, along with the cell salvage technique throughout surgery. The third group (group III, n = 22) received aprotinin in which 5,000,000 KIU Trasylol was applied during surgery, and a combination group (group IV, n = 18) was treated with all three approaches, i.e., APP, CS, and aprotinin. Compared with group I (896+/-278 mL), the postoperative total blood loss was significantly reduced in groups II, III, and IV (468+/-136, 388+/-122, 202+/-81 mL, respectively, p < 0.05). The requirements of packed red blood cells in the three approached groups (153+/-63, 105+/-178, 0+/-0 mL, respectively) also were reduced when compared with group I (343+/-118 mL, p < 0.05). In group I, six patients (6/10) received fresh-frozen plasma and three patients (3/10) received platelet transfusion, whereas no patients in the other three groups required fresh-frozen plasma and platelet. In conclusion, both plateletpheresis concomitant with cell salvage and aprotinin contribute to the improvement of postoperative hemostasis, and the combination of these two approaches could minimize postoperative blood loss and requirement.

Acute Disease↗
PubMed2005

[The influence of leukocyte depletion filter-LD-1 on leukocytes, IL-6, MPO and the pathologic changes of myocardic tissues during cardiopulmonary bypass].

OBJECTIVE: To elucidate the influence of the leukocyte depletion filter (LD-1) on leukocytes, IL-6, myeloperoxidase enzyme (MPO) and the pathological changes of myocardic tissues during cardiopulmonary bypass(CPB). METHODS: Twelve dogs were used in this study. The LD-1, designed and made by ourselves, was fixed on the venous line in the trial group (n=6). It was used during the first 5 min after 2 min of CPB. LD-1 was not installed in the control group (n=6). Circulating leukocytes were counted before CPB, at 10 min, 40 min, 75 min during CPB, at the end of CPB, and 2 h after CPB. Plasma levels of IL-6 and MPO were also determined at the same time. The pathologic changes of left ventricular biopsies were observed before CPB, 5 min after protamine was given, and 2 h after CPB. RESULTS: The CPB 10 min WBC Count fell to 36% of that Before CPB in LD-1 group, which was lower than the WBC count in the control group synchronously (P < 0.01). But after CPB 2 h, both of them were close to the levels Before CPB in the two groups. In LD-1 group, IL-6 increased at CPB 40 min and reached to the top. But after wards it dropped continuously. The changes were of no significance in MPO and in the pathological examination of myocardic tissues (P > 0.05). CONCLUSION: The LD-1 on venous line was capable of decreasing WBC count effectively. As a result, the inflammation factors that leukocytes released were lower, so the program chain of inflammation by CPB was shorter. But LD-1 was not superior in myocardial preservation.

Animals↗
PubMed2005

[Analytical algorithms improving the reconstruction of SPECT image].

Single photon emission computed tomography (SPECT) is a cost-effective, widely-used diagnostic modality for the assessment of cardiac and cerebral functions. However, most SPECT protocols for clinical use support only qualitative reconstruction. Its lack of quantitative capability compromises the accurate evaluation of diseases. Quantitative SPECT by simultaneous compensation for different degradation factors is in great demand and should improve the diagnosis greatly. The variety of the existing SPECT algorithm can be split into a family of analytical methods and a wide class of iterative techniques. By reviewing the research work published in the past decades, this paper tries to make a state of arts and comprehensive outline of efficient, analytical solutions to SPECT reconstruction problem, which could compensate scatter, photon attenuation, and detector response, as well as suppression of Poisson noise, respectively.

Algorithms↗
PubMed2005

[The in vitro model of inhalation anesthesia using rodent ventilator].

OBJECTIVE: To set up a method of applying inhalation anesthesia in rodent using rodent ventilator and to study the dynamic procedure of the in vitro model. METHODS: The output port of the anesthesia machine was connected to the input port of the rodent ventilator, which was connected to a syringe simulating the lung. After supply of anesthetic gas, the gas samples from the input port of the ventilator and the syringe in the end-expiratory phase were collected at 10, 20, 30, 40, 50, 60, 90, 120, 180, 300, 600 and 900 seconds respectively and were determined using the gas chromatography(GC). The ratios of the anesthetic concentrations of the syringe to that of the input port were calculated (CE/CI). In elimination phase, the gas samples from the syringe were collected at 0,10, 20, 30, 40, 50, 60, 90, 120, 180, 300, 600 and 900 seconds respectively and were determined by GC. The ratios of the anesthetic concentrations of the gas at 10, 20, 30, 40, 50, 60, 90, 120, 180, 300, 600 and 900 seconds to that at 0 second were calculated(C'E/C0). RESULTS: CE/CI increased in the inhalation phase, there was an inverse relationship between CE/CI and time, the correlation coefficients were 0.90, 0.95 and 0.93 respectively (P < 0.01). The mathematical fitting equations were y = -0.19 + 0.19x(-1), y = -7.75 + 0.99x(-1), and y = -7.21 + 0.97x(-1) respectively. C'E/C0 decreased in the elimination phase,the correlation coefficients were 0.90, 0.94 and 0.95 respectively (P < 0.01). The mathematic fitting eqations were y = 5.65-0.02x(-1), y = 7.82-0.01x(-1),and y = 8.20-0.01x(-1), respectively. CONCLUSION: The in vitro model of rodent inhalation anesthesia using the rodent ventilator was set up. The establishment of this model has provided a basis for studies on inhalation anesthesia in rodents.

Anesthesia, Inhalation↗
PubMed2005

[Synchronization of the activity of gamma oscillation and ERP components].

In the present study the activity of the gamma oscillation synchronized with the stimuli and ERP is investigated by means of unimodal and bimodal experiments. The multiresolution wavelet algorithm is used for signal extraction and Gabor transform is employed to represent the temporal evolution of the selected frequency components. The results show that the gamma oscillation is strongly phase-locked not only with the exogenous stimuli in the three experiments, but also with the endogenous components of ERPs (N2b, P300). And the ERP and the gamma oscillation induced by the bimodal stimuli show the audio-visual bisensory integration and relationship. In addition, the results from the experiments with the auditory stimuli show that the gamma oscillation may be closely related to the perception of auditory signals.

Adult↗
PubMed2005

[Intergration and epression of porcine endogenous retrovinus in the immortal cell line of Banna Minipig Inberd Line-Mesenhymal Stem Cells].

OBJECTIVE: To detect the integration and expression of porcine endogenous retrovirus (PERV) in the immortal cell line of Banna Minipig Inbred Line-Mesenchymal Stem Cells (BMI-MSCs). METHODS: DNA and total RNA of the immortal cell line of BMI-MSCs were extracted and PCR, RT-PCR were performed to detect PERV-gag, pol and env gene, and the type of PERV was also detected. RESULTS: PERV-gag, pol and env gene were all detected in the primary culture and immortal cell line (passage 150 and passage 180) of BMI-MSCs, and the type of PERV was PERV-A, B. Functional expression of PERV-gag and pol mRNA was also detected. CONCLUSION: In this laboratory, PERV was not lost during the proceeding of pig inbred and since has been in long-term culture of pig cells in vitro. PERV has integrated into the genome of its natural host, and virus mRNA can effectively express. So it is very essential to evaluate the possibility of xenozoonoses in pig-to-human xenotransplantation.

Animals↗
PubMed2005

[Automated anesthesia record system].

Based on Client/Server architecture, a software of automated anesthesia record system running under Windows operation system and networks has been developed and programmed with Microsoft Visual C++ 6.0, Visual Basic 6.0 and SQL Server. The system can deal with patient's information throughout the anesthesia. It can collect and integrate the data from several kinds of medical equipment such as monitor, infusion pump and anesthesia machine automatically and real-time. After that, the system presents the anesthesia sheets automatically. The record system makes the anesthesia record more accurate and integral and can raise the anesthesiologist's working efficiency.

Anesthesia↗
PubMed2004

A comparison of acetyl- and methoxycarbonylnitrenes by computational methods and a laser flash photolysis study of benzoylnitrene.

Density functional theory (DFT), CCSD(T), and CBS-QB3 calculations were performed to understand the chemical and reactivity differences between acetylnitrene (CH(3)C(=O)N) and methoxycarbonylnitrene (CH(3)OC(=O)N) and related compounds. CBS-QB3 theory alone correctly predicts that acetylnitrene has a singlet ground state. We agree with previous studies that there is a substantial N-O interaction in singlet acetylnitrene and find a corresponding but weaker interaction in methoxycarbonylnitrene. Methoxycarbonylnitrene has a triplet ground state because the oxygen atom stabilizes the triplet state of the carbonyl nitrene more than the corresponding singlet state. The oxygen atom also stabilizes the transition state of the Curtius rearrangement and accelerates the isomerization of methoxycarbonylnitrene relative to acetylnitrene. Acetyl azide is calculated to decompose by concerted migration of the methyl group along with nitrogen extrusion; the free energy of activation for this concerted process is only 27 kcal/mol, and a free nitrene is not produced upon pyrolysis of acetyl azide. Methoxycarbonyl azide, on the other hand, does have a preference for stepwise Curtius rearrangement via the free nitrene. The bimolecular reactions of acetylnitrene and methoxycarbonylnitrene with propane, ethylene, and methanol were calculated and found to have enthalpic barriers that are near zero and free energy barriers that are controlled by entropy. These predictions were tested by laser flash photolysis studies of benzoyl azide. The absolute bimolecular reaction rate constants of benzoylnitrene were measured with the following substrates: acetonitrile (k = 3.4 x 10(5) M(-1) (s-1)), methanol (6.5 x 10(6) M(-1) s(-1)), water (4.0 x 10(6) M(-1) s(-1)), cyclohexane (1.8 x 10(5) M(-1) s(-1)), and several representative alkenes. The activation energy for the reaction of benzoylnitrene with 1-hexene is -0.06 +/- 0.001 kcal/mol. The activation energy for the decay of benzoylnitrene in pentane is -3.20 +/- 0.02 kcal/mol. The latter results indicate that the rates of reactions of benzoylnitrene are controlled by entropic factors in a manner reminiscent of singlet carbene processes.

Journal Article↗
PubMed2004

Photoreactions of cisoid 1,4-diphenyl-1,3-butadienes. Direct irradiation in solution and in low temperature organic glass.

The photoreactions of 1,4-diphenyl-1,3-butadienes (DPB) fused with a bicyclo[2.2.1]heptano ring under direct irradiation were examined in solution at room temperature and in organic glass at liquid nitrogen temperature. Photocyclization yielding a phenylnaphthalene compound was shown to be preceded by facile E,E to E,Z photoisomerization. The reverse E,Z to E,E isomerization took place with equal ease in low temperature organic glass and in solution at room temperature. The pattern of reaction at low temperature is consistent with the involvement of the Hula-twist mechanism. However, complexity in conformational population, suggested by ab initio calculated data, made the experimental evidence less clear-cut than in previously reported examples of HT.

Journal Article↗
PubMed2004

Recent pharmacological studies on natural products in China.

Natural products have been used as medicinal agents for many years. In addition, these compounds have also served as the starting points for semisynthetic analogs with improved properties. This review focuses on recent advances in the pharmacological studies on natural products mainly performed and published in China. Emphasis will be placed on those compounds that show the greatest promise clinically such as huperzine A (9-amino-13-ethylidene-11-methyl-4-azatricyclo[7.3.1.0(3.8)]trideca-3(8),6,11-trien-5-one), s-(-)-3-n-butylphthalide (s-(-)-3-butyl-1(3H)-isobenzofuranone), (-)-clausenamide (3-hydroxy-4-phenyl-5a-hydroxybenzyl-N-methyl-gamma-lactam) and Ginkgo biloba extract and its active components.

Alkaloids↗
PubMed2004

Phase transition of a single lipid bilayer measured by sum-frequency vibrational spectroscopy.

In this communication, we demonstrate the first use of sum-frequency generation (SFG) vibrational spectroscopy to measure directly the phase transition temperature (Tm) of a single planar supported lipid bilayer (PSLB). Three saturated phospholipids, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-diheptadecanoyl-sn-glycero-3-phosphocholine (DHPC), and 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), were studied. Lipid bilayer films were prepared by the the Langmuir-Blodgett method at a surface pressure of 30 nN/m. The symmetric nature of the bilayer was used to determine the Tm of bilayers by measuring the intensity of the symmetric methyl stretch at 2875 cm-1 from the lipid fatty acid chains as a function of temperature. A maximum in the CH3 symmetric stretch transition was observed at the Tm of the lipid film due to the reduction of symmetry in the bilayer. The SFG measured Tm for DPPC, DHPC, and DSPC were 41.0 +/- 0.4, 52.4 +/- 0.7, and 57.9 +/- 0.5 degrees C, respectively. These values correlate well with the literature values of 41.3 +/- 1.8, 49 +/- 3, and 54.5 +/- 1.5 degrees C for DPPC, DHPC, and DSPC, respectively obtained by differential scanning calorimetry (DSC) of lipid vesicles in solution. The high degree of correlation between the SFG spectroscopic measurements and the DSC results suggests the Tm of these lipids is not significantly altered upon immobilization on a surface.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2004

Direct measurement of the transbilayer movement of phospholipids by sum-frequency vibrational spectroscopy.

The direct measurement of the transbilayer movement of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) in a planar supported lipid bilayer (PSLB) at the fused silica/D2O interface was obtained with sum-frequency generation (SFG) vibrational spectroscopy. The intrinsic sensitivity of SFG to the symmetry of an interface was used to measure the asymmetric distribution of DSPC and perdeuterated DSPC (DSPC-d83) lipids in asymmetrically prepared DSPC/DSPC-d83 PSLBs. Changes in the membrane lipid composition due to exchange between leaflets was monitored by measuring the decay in the CH3 symmetric stretch intensity at 2875 cm-1 with time. The activation energy for transverse motion was determined directly from spectral relaxation measurements at several temperatures and was determined to be 206 +/- 18 kJ/mol. At room temperature (25 degrees C) the half-time of lipid flip-flop was calculated to be approximately 25 days. At 51 degrees C, only 7 degrees C below the main phase-transition temperature of DSPC, the half-time decreases to 25 min. These results have important implications for understanding the transbilayer movement of lipids in biological membranes.

Kinetics↗
PubMed2004

Differential regulation of resveratrol on lipopolysacchride-stimulated human macrophages with or without IFN-gamma pre-priming.

Resveratrol, a polyphenol compound found in grapes and red wines, is a prominent anti-cancer agent. In this study, we demonstrate that resveratrol enhanced TNF-alpha, IL-12 and IL-1beta production from LPS activated phorbol myristate acetate (PMA) differentiated THP-1 human macrophages. Expression of CD86 on macrophages was enhanced by resveratrol alone and with LPS. When macrophages were primed with IFN-gamma, resveratrol suppressed the expression of HLA-ABC, HLA-DR, CD80, CD86 and inhibited production of TNF-alpha, IL-12, IL-6 and IL-1beta induced by LPS. The differential impact of resveratrol on expression of CD14 might be correlated with differential response of macrophages to LPS with or without IFN-gamma priming.

Antigen-Presenting Cells↗