Biomedical subjects

J Yin

Publications and source records attributed to J Yin.

At least 73 records · Page 4Linked to original sources

PubMed2000

Apoptosis of vascular smooth muscle cells induced by cholesterol and its oxides in vitro and in vivo.

The ability of cholesterol and its oxides to induce apoptosis in vascular smooth muscle cells in tissue culture and in a rabbit model of atherosclerosis was evaluated. Apoptosis was detected using DNA laddering and in situ end-labelling of fragmented DNA. Cholesterol oxides, but not cholesterol, were found to inhibit proliferation and induce apoptosis of vascular smooth muscle cells in tissue culture. 7-ketocholesterol was found to be the most potent inhibitor of proliferation, while 25-hydroxycholesterol was found to be the most potent inducer of apoptosis. These data suggest that the inhibition of proliferation and the induction of apoptosis by cholesterol oxides within vascular smooth muscle cells use different pathways, suggesting a differential role for these cholesterol oxides within the arterial wall. Cholesterol feeding after balloon injury in a rabbit model of atherosclerosis is known to result in the accumulation of cholesterol oxides. However, we found that cholesterol feeding had no effect on the level of apoptosis in the rabbit aortic wall after balloon injury, suggesting that the major factor determining apoptosis in our model was the balloon injury.

Animals↗

PubMed2000

Construction and selection of the novel recombinant Escherichia coli strain for poly(beta-hydroxybutyrate) production.

Heterogeneous cloning of Vitreoscilla hemoglobin gene (vgb), lytic genes of phage lambda with S amber mutation (S(-)RRz) and PHB biosynthetic genes (phbCAB) in the same host strain E. coli JM105 was carried out for production of poly(beta-hydroxybutyrate) (PHB). A superior novel strain, VG1 (pTU14), was constructed and selected, which contained the vgb gene in the chromosomal DNA and the plasmid pTU14 containing S(-)RRz and phbCAB genes. When cultured in 100 ml of LBG medium in a 300-ml flask, all of the exogenous genes in VG1 (pTU14) were expressed. The cell concentration of VG1 (pTU14) grown by batch culture in a flask reached 10.2 gl(-1); PHB concentration, PHB content and PHB yield, which is the ratio of the PHB accumulation to the glucose consumption, were 8.54 gl(-1), 84% and 0.43 gg(-1), respectively. When cultured by batch-feeding of glucose in a 300-ml shaking flask, the cell concentration and PHB content reached 26 gl(-1) and over 96%, respectively.

Journal Article↗

PubMed2000

Alkylation of cysteine-containing peptides to mimic palmitoylation.

Numerous proteins that are involved in cell signaling and viral replication require post-translational modification by palmitoylation to function properly. The molecular details by which this palmitoyl modification affects protein function remain poorly understood. To facilitate in vitro biochemical and structural studies of the role of palmitoylation on protein function, a method was developed for alkylating peptides with saturated C16 groups at cysteine residues and demonstrated using peptides derived from the palmitoylated region of Sindbis virus E2 glycoprotein. The synthetic approach takes advantage of disulfide chemistry to specifically modify only the cysteine residues within peptides and covalently links C16 groups via disulfide bridges using a new thioalkylating reagent, hexyldexyldithiopyridine. The chemistry presented here takes place in solution under mild conditions without the need for protection of the peptide functional groups. A method for purifying these modified peptides is also described. This protocol can be of general use to investigators studying the role of palmitoylation in biological systems.

Alkylation↗

PubMed2000

Tryptophan 140 is important, but serine 141 Is essential for the formation of the integrated conformation of staphylococcal nuclease.

A series of N-terminal fragments of staphylococcal nuclease with different chain lengths has been taken as an in vitro nascent peptide folding model. Previous studies have shown that nascent peptide folding of the nuclease may begin early in the synthetic process with the content of ordered secondary structure increases with increasing peptide chain length, and that conformational adjustments are observed at certain stages during nascent peptide folding. Here, we focus attention on the conformational changes in the later stage of nascent peptide folding of the nuclease when the N-terminal fragment elongates nearly to the C-terminus of the nuclease in order to determine the role of the C-terminal region of the nuclease in the formation of the integrated conformation of the nuclease. We compared the conformational features of SNase R and its larger N-terminal fragments SNR135, SNR139, SNR140, and SNR141 using circular dichroism spectra, ANS-binding fluorescence and intrinsic fluorescence spectra. The results show that Trp140 is important for the enrichment of ordered secondary structure and for producing a greater ability to fold into a native-like conformation, but Ser141 is essential for the formation of the integrated conformation of the nuclease with a tightly packed tertiary structure. Note that the addition of only one residue to the C-terminus of elongating peptide chain can cause a dramatic change in conformation. The data also show the occurrence of continuous adjustments in conformation during peptide elongation, even after a rigid tertiary structure has formed, suggesting that the last eight residues (residues 142-149), which are disordered at the C-terminus of the nuclease, also possess a structural role, forming the native tertiary structure to provide a framework for the active site, even though they are remote from the active site in both sequence and spatial structure.

Anilino Naphthalenesulfonates↗

PubMed2000

Effectiveness of early physical therapy in the treatment of acute low back musculoskeletal disorders.

This study was designed to evaluate the effects of early physical therapy intervention on treatment outcomes for workers with acute low back injuries. A total of 3867 cases were randomly selected from the database of a large occupational health care provider. Cases were assigned to either the early therapy intervention group or one of the two comparison groups on the basis of their delay to physical therapy. The treatment outcomes for the three groups were compared. The results showed that patients in the early therapy intervention had more favorable outcomes than the two comparison groups. Specifically, patients in the early intervention group had fewer physician visits, fewer restricted workdays, fewer days away from work, and shorter case duration. These results provide a strong indication for the effectiveness of early therapy intervention. The financial implications of the findings is discussed.

Absenteeism↗

PubMed2000

Toward antiviral strategies that resist viral escape.

We studied the effect on viral growth of drugs targeting different virus functions using a computer simulation for the intracellular growth of bacteriophage T7. We found that drugs targeting components of negative-feedback loops gain effectiveness against mutant viruses that attenuate the drug-target interaction. The greater inhibition of such mutants than of the wild type suggests a drug design strategy that would hinder the development of drug resistance.

Antiviral Agents↗

PubMed2000

A method to determine the fractal dimension of the cross-sectional jaggedness of the infarct scar edge.

This study describes the use of a shareware software package available from the National Institutes of Health for computing the fractal dimension. Specifically, when fractal analysis is used in its correct context it provides for a quantitative description of the space filling properties of two-dimensional objects. A rabbit model of post myocardial infarction is described where the cross-sectional infarct edge is reconstructed and its jaggedness determined by calculating its fractal dimension via the pixel dilation method. The fractal dimensions of the anterior and posterior lateral infarct edges were calculated to have a mean of 1.16 and 1.29, respectively. In conclusion, the fractal technique can be used to describe the complex jaggedness of the infarct edge. This case study also illustrates the fact that the complexity of an infarcted area is not uniform across the scar. For example, we found that the space filling properties of the anterior and posterior borders of a myocardial infarct can differ by more than 2-fold.

Animals↗

PubMed2000

Genetic polymorphism of group-specific component/vitamin-D-binding protein subtypes in six populations from north-eastern China.

On six populations from North-Eastern China the frequencies of Gc subtypes were studied by isoelectric focusing on ultra-thin polyacrylamidegel followed by the improved sulfosalicylic acid precipitation. The following Gc subtype allele frequencies could be observed in the Han (Harbin), Ewenki, Tahur, Mongolian, Oroquen and Xibe populations: Gc*1F = 0.4246, 0.4941, 0.4479, 0.4077, 0.4606 and 0.4503; Gc*1S = 0.2587, 0.2936, 0.3151, 0.2822, 0.3370 and 0.3035; Gc*2 = 0.3065, 0.2064, 0.2266, 0.3006, 0.2022 and 0.2388. In addition to this 16 individuals of five populations showed rare Gc variant alleles (1A3, 1A8, 1A9, 1A14, 1C?).

Alleles↗

PubMed2000

[Rational range and optimum proportion of energy input in farmland].

There exists a rational range of artificial supplemental energy inputs in fields. In the range, the inputs can improve the yield and the output/input ratio. The rational range of energy input in total energy output is bigger than that in the output/input ratio. It is bigger in low yield fields than high yield fields, which suggests that increasing artificial supplemental energy input can increase the production of low yield fields as same as high yield fields. In the rational range of energy input, there exist high efficient lines in water and fertilizer inputs. The highest efficiency occurs when the rational inputs of water and fertilizer occur in these two lines. There also exist optimum lines of energy and economy input proportions. In the two lines, the proportions of energy and economy output/input of water and fertilizer inputs are the highest, which are the optimum of water and fertilizer inputs. Water and fertilizer may replace each other for equal yields, but would result in a decrease in the output/input ratio.

Crops, Agricultural↗

PubMed2000

[Imaging diagnosis for abdominal tuberculous lymphadenopathy].

OBJECTIVE: To evaluate the value of X-ray imaging for diagnosing abdominal tuberculous lymphadenopathy. METHODS: 27 cases of tuberculous lymphadenopathy proved by clinical or pathohistological evidence were collected, all of which were examined with radiological imaging methods. RESULTS: The typical CT findings enlarged lymph nodes with peripheral or multilocular enhancement. Enlarged lymph nodes with multiple flecked or massive calcifications were important for diagnosis. Ultrasound examination showed enlarged lymph nodes with uniform echo (less than 2 cm) and with heterogeneous echo (larger than 2 cm). The aim of the barium meal examination of the gastrointestinal tract was to find tuberculous lymphadenopathy encroaching on intestine or merged with intestinal tuberculosis. Abdominal X-ray plain film was helpful to find the calcified tuberculous lymphadenopathy and intestinal obstruction. CONCLUSIONS: Various imaging methods have shown their diagnostic value, but CT was the most important tool for definite diagnosis of tuberculous lymphadenopathy. Ultrasound was more useful for follow-up cases.

Adolescent↗

PubMed2000

[Combined phacoemulsification, foldable intraocular lens implantation and trabeculectomy for cataract patients with glaucoma].

OBJECTIVE: To evaluate the therapeutic effects and safety of the combined phacoemulsification, foldable intraocular lens implantation and trabeculectomy (triple procedure) and compare the outcomes of the operation with two different small incisions, conventional scleral flap and scleral tunnel flap. METHODS: Triple procedure was performed through a 3.5 mm incision by means of conventional scleral flap or scleral tunnel flap on 44 eyes of 42 patients with cataract and glaucoma. RESULTS: After follow-up for 3 -- 6 months, the mean intraocular pressure (IOP) was (14.33 +/- 3.68) mm Hg (1 mm Hg = 0.133 kPa) with a mean pressure reduction of 10.35 mm Hg from that before the operation (P < 0.001). Postoperatively, the visual acuities were >or= 0.5 in 33 eyes (75.0%) at 1 week and in 37 eyes (84.1%) during 3 - 6 months. The mean postoperative astigmatism was (1.29 +/- 0.93) D at 1 week and only 0.17D more than the mean preoperative one (P > 0.05). There was also no statistical difference between the mean preoperative astigmatism and postoperative astigmatism at 3 - 6 months, which was (1.12 +/- 0.73) D. The filtering blebs of type I and II (functional) by Kronfeld's classification presented in 79.5% of the eyes and type III (non-functional) in 20.5% of the eyes. There were no statistical differences for the postoperative outcomes of IOP, visual acuity, astigmatism and filtering bleb between two different procedure groups (P > 0.05). CONCLUSIONS: The triple procedure is an effective, quick, repeatable and safe procedure for cataract patients with glaucoma. There are no differences at the surgical outcomes of two different incisions by means of the conventional scleral flap vs scleral tunnel flap.

Adult↗

PubMed2000

[Study on production of poly-beta-hydroxybutyrate by recombinant strain VG1(pTU14)].

Cloning and expression of Vitreoscilla hemoglobin gene (vgb) and lambda phage lytic genes (S-RRz) in production of Poly-beta-hydroxybutyrate(PHB) was studied in different Escherichia coli hosts such as E. coliJM105, E. coliJM109 and VG1. In the recombinant strains, VG1(pTU14) was a superior one which simultaneously contained three exogenes including vgb, S-RRz and PHB biosynthesis genes(phbCAB). The experimental results showed that after 82 hours fed-batch cult ure in LBG medium in shaking flask, cell concentration of VG1(pTU14) could reach 25.9 g/L, which was the highest PHB production ever reported, and till 52 h PHB content could be higher than 95%. Additionally, inducible cell lysis was also attained successfully in recombinant VG1(pTU14) accompanying with its high cell density culture. Therefore, VG1(pTU14) is a novel potential strain with promising prospect in industrial production of PHB.

Bacterial Proteins↗

PubMed2000

[Pharmacodynamic effects of the extracts from Orobanche cumana].

Pharmacodynamic effects of the extracts from Orobanche cumana were studied for the first time. The result showed that it has the effects of antifatigue, facilitating immune function and an andrin-like action. It is consided that Orobanche cumana can be developed as a new medicinal resource plant.

Adjuvants, Immunologic↗

PubMed1999

Amplification and spread of viruses in a growing plaque.

The two-dimensional propagation of viruses through a "lawn" of receptive hosts, commonly called plaque growth, reflects the dynamics of interactions between viruses and host cells. Here we treat the amplification of viruses during plaque growth as a reaction-diffusion system, where interactions among the virus, uninfected host cells, and virus-producing host-virus complexes are accounted for using rates of viral adsorption to and desorption from the host-cell surface, rates of reproduction and release of progeny viruses by lysis of the host, and by the coupling of these reactions with diffusion of free virus within the agar support. Numerical solution of the system shows the development of a traveling wave of reproducing viruses, where the velocity of the wave is governed by the kinetic and diffusion parameters. The model has been applied to predict the propagation velocity of a bacteriophage plaque. Different mechanisms may account for the dependence of this velocity on the host density during early stages of a growing plaque. The model provides a means to explore how changes in the virus-host interactions may be manifest in a growing plaque.

Escherichia coli↗

PubMed1999

Delay in opening the infarct related coronary artery increases plasma atrial natriuretic peptide levels.

Plasma atrial natriuretic peptide (ANP) levels were measured in rabbits during the late healing phase of myocardial infarcts. Significant differences in plasma ANP levels (P < 0.02) were found between rabbits that had undergone very late (6 h) or early reperfusion (20 and 45 min of ischemia) of the infarct related coronary artery. Differences in ANP levels were independent of infarct size, ventricular remodeling and infarct expansion. We conclude late reperfusion of infarct related artery, independent of myocardial salvage, is associated with increased circulating ANP plasma levels.

Animals↗

PubMed1999

Experimental studies on affinity chromatography in an electric field.

A multicompartment electrolyzer, which has been used for preparative electrophoresis [Z. Liu, Z. Huang, J.-Y. Cong, et al., Sep. Sci. Technol. 31 (1996) 427], is applied for carrying out affinity chromatography in an alternating electric field. The effect of electric field strength on the adsorption and desorption characteristics is experimentally examined with human serum albumin and Blue Sepharose Fast Flow as a model system. It is shown that the existence of an electric field leads to a significant change in the adsorption capacity of the blue dye, which may be used for establishing a preferential adsorption to achieve a high resolution. The adsorption speed increases slightly with respect to the increase of electric field strength, while adsorption capacity in the presence of an electric field is independent of the electric field strength. Different elution behavior is observed as function of adsorption condition and a high recovery of the adsorbed protein is obtained when the adsorption is carried out in the presence of an electric field.

Buffers↗

PubMed1999

The antiapoptotic decoy receptor TRID/TRAIL-R3 is a p53-regulated DNA damage-inducible gene that is overexpressed in primary tumors of the gastrointestinal tract.

Both DR4 and DR5 have recently been identified as membrane death receptors that are activated by their ligand TRAIL to engage the intracellular apoptotic machinery. TRID (also named as TRAIL-R3) is an antagonist decoy receptor and lacks the cytoplasmic death domain. TRID protects from TRAIL-induced apoptosis by competing with DR4 and DR5 for binding to TRAIL. TRID has been shown to be overexpressed in normal human tissues but not in malignantly transformed cell lines. DR5 is a p53-regulated gene and we have recently reported that DR5 expression is induced in response to genotoxic stress in both a p53-dependent and independent manner (Sheikh et al., 1998). In the current study, we demonstrate that TRID gene expression is also induced by the genotoxic agents ionizing radiation and methyl methanesulfonate (MMS) in predominantly p53 wild-type cells, whereas UV-irradiation does not induce TRID gene expression. Consistent with these results, exogenous wild-type p53 also upregulates the expression of endogenous TRID in p53-null cells. Thus, TRID appears to be a p53 target gene that is regulated by genotoxic stress in a p53-dependent manner. Using primary gastrointestinal tract (GIT) tumors and their matching normal tissue, we also demonstrate for the first time that TRID expression is enhanced in primary tumors of the GIT. It is, therefore, possible that TRID overexpressing GIT tumors may gain a selective growth advantage by escaping from TRAIL-induced apoptosis.

Adenocarcinoma↗

PubMed1999

Expression of the wild-type insulin-like growth factor II receptor gene suppresses growth and causes death in colorectal carcinoma cells.

The insulin-like growth factor II receptor (IGFIIR) has been implicated as a tumor suppressor gene in human malignancy. Frequent mutation, loss of heterozygosity, and microsatellite instability (MSI) directly affecting the IGFIIR gene have been reported in several primary human tumor types. However, to our knowledge, dynamic functional evidence of a growth-suppressive role for IGFIIR has not yet been provided. We identified one MSI-positive colorectal carcinoma cell line, SW48, with monoallelic mutation in IGFIIR identical to that seen in primary colorectal carcinomas. A zinc-inducible construct containing the wild-type IGFIIR cDNA was stably transfected into SW48 cells. Growth rate and apoptosis were compared between zinc-treated, untreated, and untransfected cells. A twofold increase in IGFIIR protein expression was detected after zinc treatment in discrete clonal isolates of transfected SW48 cells. Moreover, zinc induction of exogenous wild-type IGFIIR expression reproducibly decreased growth rate and increased apoptosis. These data prove that wild-type IGFIIR functions as a growth suppressor gene in colorectal cancer cells and provide dynamic in vitro functional support for the hypothesis that IGFIIR is a human growth suppressor gene.

Adenocarcinoma↗