Biomedical subjects

Jin Liu

Publications and source records attributed to Jin Liu.

100 records · Page 6Linked to original sources

PubMed2002

Stereoselective Stobbe condensation of ethyl methyl diphenylmethylenesuccinate with aromatic aldehydes.

The E configuration of benzylidene(diphenylmethylene)succinic anhydride (R = H), obtained by the Stobbe condensation of ethyl methyl diphenylmethylenesuccinate with benzaldehyde, was determined by single-crystal X-ray diffraction. Noncovalent pi stacking interaction between two stacked phenyl groups is suggested as a stabilizing energy for the highly crowded molecule. The nature and the position of substituents (R) on the aromatic rings of substituted benzaldehydes showed no effect on the E stereoselectivity in the condensation. [structure: see text]

Journal Article↗

PubMed2002

[Incidence of senile dementia and depression in elderly population in Xicheng District, Beijing, an epidemiologic study].

OBJECTIVE: To investigate the incidence of senile dementia and depression in the elderly and the factors correlative with these disorders. METHODS: All the non-case subjects investigated in a survey of prevalence of senile dementia and depression conducted among the elderly population in Xicheng District, Beijing in 1997 were followed up in 1999. The investigation procedure, instruments and diagnostic criteria were identical with those used in 1997 survey. RESULTS: The annual incidence rates of senile dementia was 0.89% in those aged 60 and over. The incidence rate of old males and that of the old females were not significantly different. The annual incidence rate of senile dementia in groups aged 60 approximately 64, 64 approximately 69, 70 approximately 74 75 approximately 79 80 approximately 84 85 approximately 89, and 90 and over were 0.15% 0.68 % 0.44% 1.32% 2.41% 5.72% and 5.13% respectively. The incidence rate in the elderly over 90 was lower than that in the group aged 85 approximately 89. The minimum annual incidence rate of depression in the elderly aged 60 and over was 1.28%. The incidence rate of depression was higher in the group with poorer health than in the group with better health. The incidence rates of moderate and severe dementia were not significantly different from those in 1989. CONCLUSION: The incidence rate of senile dementia in the elderly remains rather stable during this period of 10 years in Beijing city. The incidence rate of senile dementia is closely correlated with age. The incidence rate of depression in the elderly is remarkably correlated with health status. Senile dementia and depression may coexist in the same person.

Aged↗

PubMed2002

Study of alpha-crustacyanin utilizing halogenated canthaxanthins.

[structure: see text] The preparations and spectroscopic characteristics of five all-trans halogenated canthaxanthins are described in this letter. The air/light-sensitive halogenated canthaxanthins were used to study alpha-crustacyanin, a blue astaxanthin-protein complex, which is isolated from the carapace of the lobster. Steric and electronegative effects of the halogen substituents on the noncovalent interaction between astaxanthin and the protein in alpha-crustacyanin were observed.

Animals↗

PubMed2002

Tissue solubility of four volatile anesthetics in fresh and frozen tissue specimens from swine.

OBJECTIVE: To determine tissue solubilities of desflurane, sevoflurane, enflurane, and halothane in swine and to evaluate the effects of freezing specimens on tissue solubility, SAMPLE POPULATION: Arterial blood samples and specimens of brain, heart, liver, kidney, muscle, and subcutaneous fat from 5 healthy female adult Chinese Meishan pigs. PROCEDURE: Each tissue specimen was divided into 2 parts. One part was used to measure tissue-gas partition coefficients immediately after collection. The other part was frozen at -20 C for 6 days prior to determination of tissue-gas partition coefficients. Tissue-gas and blood-gas partition coefficients were measured by use of gas chromatography, and tissue-blood partition coefficients were calculated. Regression analysis was performed to determine whether fat-gas partition coefficients were correlated with lean tissue-gas partition coefficients. RESULTS: Tissue-gas and blood-gas partition coefficients of halothane were greater than those of enflurane followed by coefficients of sevoflurane and desflurane. However, the order of anesthetic agents with the greatest to smallest tissue-blood partition coefficients was sevoflurane, halothane, enflurane, and desflurane. Muscle-gas partition coefficients of sevoflurane and enflurane, liver-gas partition coefficients of desflurane and halothane, and the kidney-gas partition coefficient of enflurane were significantly greater in frozen specimens, compared with fresh specimens. Lean tissue-gas partition coefficients of all 4 volatile anesthetics correlated directly with fat-gas partition coefficients. CONCLUSIONS AND CLINICAL RELEVANCE: The fat content of lean tissue is an important factor in determining the tissue solubility of volatile anesthetics. Freezing specimens before determination of tissue-gas partition coefficients may result in a false increase in tissue solubility.

Adipose Tissue↗

PubMed2002

[The observation of local immune response in the lungs from antigen-sensitized and challenged mice].

OBJECTIVE: To evaluate the local immune response after allergic sensitization and challenge in the lungs of mice. METHODS: C57BL/6 mice were sensitized with keyhole limpet hemocyanin (KLH) by intratracheal instillation and challenged 2 approximately 4 weeks later. Bronchoalveolar lavage fluid (BALF) and plasma were collected and cells from the lung-associated lymph node (LALN), the lungs and the spleen were cultured and collected. Anti-KLH IgA, total IgA and albumin levels were measured by ELISA. RESULTS: Intratracheal instillation of KLH induced local BAL antigen-specific IgA response, and further challenge expanded this response. The ratio of anti-KLH IgA/albumin in BALF was significantly higher than that in serum after both sensitization and challenge by KLH. In vitro, cells from the LALN and the lungs released anti-KLH IgA after sensitization and challenge by KLH, but spleen cells released lower levels of anti-KLH IgA compared to the LALN and the lungs. CONCLUSIONS: Allergic sensitization by intratracheal instillation of KLH into the mouse lungs induced a local pulmonary response of specific IgA, and it was amplified by challenge with KLH. The accumulation of anti-KLH IgA in the respiratory lumen was the result of local production but not the result of simple transudation or leakage from the serum. The LALN and the lung lymphocytes were major sources of anti-specific IgA.

Animals↗

PubMed2002

Combined effect of hypothermia and crystalloid hemodilution on the solubility of volatile anesthetics in human blood.

OBJECTIVE: To determine the combined effect of hypothermia and crystalloid hemodilution on blood solubility of volatile anesthetics. METHODS: Two hundred and thirty ml blood samples obtained from each of twelve healthy male volunteers were adjusted to a hematocrit of 40% and then diluted with normal saline to hematocrits of 36%, 32%, 28%, 24%, and 20%. Blood/gas partition coefficients of desflurane, sevoflurane, isoflurane, enflurane and halothane were measured at 37 degrees C,33 degrees C, 29 degrees C, 25 degrees C, 21 degrees C and 17 degrees C using a two-stage headspace double equilibration method. RESULTS: As the temperature decreased, the logarithm of the blood/gas partition coefficient increased linearly (P < 0.05). As the hematocrit decreased, the logarithm of the blood/gas partition coefficient decreased linearly (P < 0.05). The combined effect of hypothermia and crystalloid hemodilution on blood solubility of anesthetics was expressed by multiple linear regression equations as follows: Desflurane: log(e)lambda(B/G)=-0.0302 x T+0.0094 x HCT+0.119 R(2)=0.973. Sevoflurane: log(e)lambda(B/G)=-0.0295 x T+0.0092 x HCT+0.306 R(2)=0.961. Isoflurane: log(e)lambda(B/G)=-0.0382 x T+0.0154 x HCT+1.120 R(2)=0.997. Enflurane: log(e)lambda(B/G)=-0.0408 x T+0.0198 x HCT+1.408 R(2)=0.982. Halothane: log(e)lambda(B/G)=-0.0417 x T+0.0218 x HCT+1.649 R(2)=0.994. Where lambda(B/G) is the blood/gas partition coefficient, T is temperature (degrees C) and HCT is hematocrit (%). CONCLUSIONS: Hypothermia increases, while crystalloid hemodilution decreases the blood solubility of volatile anesthetics. The combined effect of hypothermia and hemodilution on blood solubility at any cross point of temperature from 37 degrees C to 17 degrees C and hematocrit from 40% to 20% could be predicted by the multiple linear regression equations developed in this study.

Adult↗

PubMed2002

[Construction of recipient strain of expression-secretion system in filamentous fungi].

Glucoamylase overproducing A. niger T21 was mutated by UV mutagensis. An extracellular acid protease-deficient mutant, A. niger T21-201, which produced only 0.76% extracellular acid protease activity of the parent strain, was screened by casein-degradating plate and determination of protease activity. Moreover, the growth properties and the ability to secrete glucoamylase of A. niger T21-201 are identical to these of starting strain T21. The comparison of expression-secretion levels of heterologous gene in A. niger T21-201 and T21 was carried out with bacterial vhb as reporter, the level of expression-secretion of VHb in A. niger T21-201 was 6-7 times higher than that in T21, but the transcriptional levels of vhb gene in both strains were similar revealed by Northern blot. Therefore, it was demonstrated that the deficiency of acid protease of recipient T21-201 has significant effect on the protection of heterologous protein.

Aspergillus niger↗

PubMedDate not supplied

Effect of developmental lead exposure on the expression of specific NMDA receptor subunit mRNAs in the hippocampus of neonatal rats by digoxigenin-labeled in situ hybridization histochemistry.

The N-methyl-D-aspartate (NMDA) receptor has an important role in learning and memory. In this study, the effects of chronic Pb exposure on NMDA receptor subunit mRNAs expression in the developing rat hippocampus were examined by digoxigenin (DIG)-labeled in situ hybridization. In Pb-exposed rats, hippocampal NR1-2a mRNA levels were significantly increased in CA1, CA4 and DG subfields at 15 days of age and CA4 and DG subfields at 20 days of age. The lead (Pb) exposure resulted in a significant increase of NR2D mRNA levels in CA1, CA2, CA4 and DG hippocampal subfields at 20 days of age. Hippocampal NR2A mRNA levels were significantly decreased in CA1, CA2, CA3 and DG subfields from 15-day-old Pb-exposed rats and CA1, CA3 and DG subfields from 20-day-old Pb-exposed rats. Hippocampal NR3A mRNA levels were also significantly decreased in CA1, CA4 and DG subfields at 15 days of age and CA1 and DG subfields at 20 days of age in Pb-exposed rats. The Pb-induced subunit specific changes in hippocampal NMDA receptor subunit mRNA expression may lead to abnormality of natural NMDA stoichiometry and interfere with the physiological function of the NMDA receptor in the development of defined neuronal connections.

Age Factors↗

PubMedDate not supplied

Development of proteomic patterns for detecting lung cancer.

Lung cancer is at present the number one cause of cancer death and no biomarker is available to detect early lung cancer in serum samples so far. The objective of this study is to find specific biomarkers for detection of lung cancer using Surface Enhanced Laser Desorption/Ionization (SELDI) technology. In this study, serum samples from 30 lung cancer patients and 51 age-and sex-matched healthy were analyzed by SELDI based ProteinChip reader, PBSII-C. The spectra were generated on WCX2 chips and protein peaks clustering and classification analyses were performed utilizing Biomarker Wizard and Biomarker Patterns software packages, respectively. Three protein peaks were automatically chosen for the system training and the development of a decision classification tree. The constructed model was then used to test an independent set of masked serum samples from 15 lung cancer patients and 31 healthy individuals. The analysis yielded a sensitivity of 93.3%, and a specificity of 96.7%. These results suggest that the serum is a capable resource for detection of specific lung cancer biomarkers. SELDI technique combined with an artificial intelligence classification algorithm can both facilitate the discovery of better biomarkers for lung cancer and provide a useful tool for molecular diagnosis in future.

Adenocarcinoma↗

PubMedDate not supplied

Mechanisms of photoisomerization of polyenes in confined media: from organic glasses to protein binding cavities.

Photochemical reactivities of model organic systems (stilbene and diphenylbutadiene) in organic glasses were first examined and compared with those in solution and in organized media. These observations were in turn compared with reactivities of polyene chromophores in protein binding cavities (specifically PYP, rhodopsin and bacteriorhodopsin). The obvious conclusion is that the preference for the most volume-conserving Hula-twist mechanism isomerization in organic glasses is because of the close interaction between the guest and the host molecules. In organized media (zeolites, crystals and protein binding cavities), the residual empty space coupled with any specific guest-host interactions that are characteristic of a given system, could lead to involvement of the more volume-demanding one-bond-flip (i.e. torsional relaxation) or bicycle-pedal or an extended HT process in photoisomerization.

Bacterial Proteins↗