Erratum: Critical dimensionalities of phase transitions on fractals
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Journal Article↗
Biomedical subjects
Y Shi
Publications and source records attributed to Y Shi.
Promotion and inhibition of activation-induced apoptosis in T-cell hybridomas by oncogenes and related signals.
The Two Signal: Death/Survival Model suggests that cellular proliferation and physiological cell death should be intimately associated such that, in the absence of external influences, a normal cell departing from rest will have an equal probability of undergoing either process. The c-Myc protooncogene product has been implicated in cell cycle progression and in the control of gene expression, and more recently c-Myc has also been seen to promote apoptotic cell death. As predicted from the model, c-Myc-induced apoptosis is inhibited by growth factors or other anti-apoptotic signals including those provided by some oncogenes. Here, we discuss experiments that test the Two Signal: Death/Survival Model in the phenomenon of activation-induced apoptosis in T-cell hybridomas. Ligation of the antigen receptor on these cells leads to activation, resulting in cytokine production and apoptosis. Inhibition of c-Myc expression by addition of antisense oligodeoxynucleotides or transforming growth factor beta inhibits this form of apoptosis. Because c-Myc is known to bind to several cellular proteins, including Max, we further examined the effects of expression of a dominant negative Max on activation-induced apoptosis. We found that this Max mutant, which interferes with the function of the Myc/Max heterodimer, inhibits the induction of apoptosis by antigen receptor ligation. Thus, both Myc and Max play roles in activation-induced apoptosis, presumably via control of gene expression. Further, as predicted, signals generated from growth factor receptors or the v-Abl oncogene interfere with activation-induced apoptosis. In contrast, the anti-apoptotic effects of Bcl-2 are not active in this form of apoptosis. Finally, a role for Fas/Fas-ligand interactions in activation-induced apoptosis is considered.
Animals↗
Cloning, sequencing, and expression in Escherichia coli of the gene encoding a 45-kilodalton protein, elongation factor Tu, from Chlamydia trachomatis serovar F.
The gene encoding a 45-kDa protein (45K) of Chlamydia trachomatis serovar F was cloned, sequenced, and overexpressed in Escherichia coli. Alignment of the deduced peptide sequence with E. coli elongation factor Tu (EF-Tu) demonstrated 69% identity. The 45K was recognized by a Chlamydia genus-specific monoclonal antibody GP-45 and cross-reacted with a monospecific polyclonal antibody to E. coli EF-Tu. Purified recombinant 45K has the capability to bind GDP, and the binding was enhanced in the presence of E. coli elongation factor Ts (EF-Ts). The GDP binding was specifically inhibited by the monoclonal antibody GP-45. These data suggest that the 45K is a chlamydial EF-Tu, and it forms a functional complex with E. coli EF-Ts protein.
Amino Acid Sequence↗
YY1 is the cellular factor shown previously to bind to regulatory regions of several leaky-late (beta gamma, gamma 1) genes of herpes simplex virus type 1.
We have recently reported that a cellular factor, the leaky-late binding factor (LBF), binds to sites in a number of leaky-late (beta gamma or gamma 1) genes of herpes simplex virus type 1 and that an LBF site is essential for maximum viral transactivation of the major capsid protein (VP5) gene. The results of binding competition, partial proteolysis, and monoclonal antibody inhibition assays presented here establish that LBF is identical to the transcription factor YY1. This, along with our previous observations, suggests that YY1 plays a role in herpes simplex virus type 1 gene regulation.
Antibodies, Monoclonal↗
Transcatheter delivery of c-myc antisense oligomers reduces neointimal formation in a porcine model of coronary artery balloon injury.
BACKGROUND: Smooth muscle cell proliferation and extracellular matrix accumulation are the principal mechanisms leading to vascular restenosis. We have previously demonstrated the growth-inhibitory effect of antisense oligomers targeting the c-myc proto-oncogene in human smooth muscle cells. The goal of this study was to investigate whether c-myc antisense oligomers reduce neointimal formation in balloon-denuded porcine coronary arteries. METHODS AND RESULTS: First, type I collagen synthesis, which reflects synthetic function, was markedly reduced following c-myc antisense oligomers in porcine vascular smooth muscle cells independent of the growth inhibition. These effects in vitro provided the rationale for assessing c-myc antisense oligomers in the prevention of neointima in vivo. Second, the efficiency of single transcatheter delivery of oligomers into denuded porcine coronary arteries was determined. Despite rapid plasma clearance following local delivery, oligomers persisted at the site of injection for at least 3 days, exceeding by severalfold their concentration in peripheral organs. Third, morphometric analyses were carried out in balloon-denuded coronary arteries at 1 month after transcatheter c-myc antisense oligomer administration. Maximal neointimal area was reduced from 0.80 +/- 0.17 mm2 in the control group (n = 12) to 0.24 +/- 0.06 mm2 in the antisense-treated group (n = 13, P < .01). Likewise, a significant reduction in maximal neointimal thickness was observed in the antisense-treated group (P < .01). These changes in vascular remodeling following denuding injury resulted in an increase in residual lumen from 64 +/- 6% in the control group to 81 +/- 5% in the antisense-treated group (P < .05). CONCLUSIONS: (1) Single transcatheter administration allowed for endoluminal delivery of oligomers to the site of coronary arterial injury. (2) C-myc antisense oligomers reduced the formation of neointima in denuded coronary arteries, implying a therapeutic potential of this approach for the prevention of coronary restenosis. (3) It is postulated that the c-myc proto-oncogene is involved in the process of vascular remodeling, regulating smooth muscle cell proliferation and extracellular matrix synthesis.
Angioplasty, Balloon, Coronary↗
Molecular basis of thyroid cancer.
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Amino Acid Sequence↗
Transgene expression in the coronary circulation: transcatheter gene delivery.
Therapeutic and research applications of direct gene transfer in the coronary vasculature are limited by varying transgene activity found in the vessel wall. It remains to be determined whether this is due to difficulties in delivery of recombinant DNA into the coronary arteries or if it relates to the state of recipient cells in the arterial wall. Accordingly, using a clinically applicable protocol, we have examined the time course of transgene (luciferase) expression in porcine coronary vasculature following transcatheter gene transfer (1 day to 4 weeks). Liposome-mediated transfection by means of a transcatheter approach resulted in detectable luciferase activity in all transfected vessels at 1 day after gene delivery. However, the activity of a reporter gene rapidly declined at 7 days thereafter, with only 33% of coronary arteries demonstrating luciferase activity. Comparable levels of transgene sequences were present in transfected vessels, although no correlation with luciferase activity was found. To further determine possible mechanisms responsible for rapidly declining transgene expression in vivo, cell proliferation was induced in the vessel wall by means of either balloon denudation or by intramural injections of platelet derived growth factor BB (PDGF-BB) into the porcine coronary vasculature at the time of gene transfer. Luciferase activity was significantly augmented (23-fold) following mitogenic stimulation in vivo as compared with the control transfected coronary arteries. These data demonstrate that a practical transcatheter approach provides an effective route to deliver recombinant DNA sequences into the coronary arterial wall.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Monoclonal antibody production and purification using miniature hollow-fiber cell culture technology.
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Animals↗
[Molecular cytogenetic study of Turner's syndrome with the 45, X/46,X,r(?) karyotype].
Two small marker chromosomes were identified as X-derived ring chromosomes by using the high-resolution banding technique and in situ hybridization with a radioactively labelled human X-chromosome-specific satellite DNA probe. This procedure clearly determined the origin of the marker chromosome, which had been impossible using conventional cytogenetic techniques. The clinical significance of this work is briefly discussed.
Adolescent↗
Epidemiology of back injury in university hospital nurses from review of workers' compensation records and a case-control survey.
Reviewing Workers' Compensation records for back injury from a large university hospital for a 2-year period, we found a yearly incidence of lost work time back injury among nurses of 2.0% per year, exceeded only by physical plant staff, who had a rate of 3.5%. Nurses' aides had an injury rate 3.3-fold higher than registered nurses and licensed practical nurses and higher than any other occupational group. We compared 100 cases of nurses with back injury in the previous 2 years with 197 noninjured control subjects using a mailed 40-item questionnaire. Multivariate logistic modelling showed that prior nonback injury and performing combined lifting activities were statistically significant risk factors for back injury, and being overweight approached significance, after adjusting for the effects of age, gender, and each of the evaluated risk factors.
Accidents, Occupational↗
[The treatment of lenticular magnetic foreign body using tri-combined operation].
Fourteen patients with lenticular magnetic foreign bodies are reported. All received magnetoperation extraction of foreign bodies combined with extracapsular cataract extraction and primary posterior chamber IOL implantation. Of them, 3 patients underwent a suture fixation of haptic in ciliary sulcus during operation due to tear of posterior capsule of lens. The operation we performed can effectively resolve the problems of the wounders' monocular blindness caused by lenticular foreign bodies and recover their binocular vision simultaneously. The results indicate that this method is good for lenticular foreign bodies. The operative method, opportunity, complication and its management are also discussed.
Adult↗
[Experimental study on compatible application of heat-clearing and detoxifying drugs with blood circulation improving drugs].
The article describes the effectiveness of compatible application of heat-clearing and detoxifying drugs with blood circulation improving drugs to the animal model with endotoxemia and nonspecific inflammation. The compatible application reduces PGE2, endotoxin blood concentration and reduced viscosity of whole blood, decreases Evans blue extravasation volume and pes swelling percentage, increases serum cortisol content and enhances fibrinolytic activity. The experimental result shows that in most cases these two drugs work better when used in combination which implies that compatible application is more effective in detoxification, antiinflammation and inflammation recovery.
Animals↗
Comparing ethnic group-specific DAI equations with the standard DAI.
The Standard DAI is an orthodontic index based on public perceptions of dental aesthetics in the USA and is a regression equation linking the relative social acceptability of dental appearance and the objective, physical measurements of ten occlusal traits. It can be used in surveys of need for orthodontic treatment and as a screening tool in public programmes providing orthodontic care. To determine if the Standard DAI could be used internationally, 200 stimuli (photographs of dental configurations) were rated for dental aesthetics by 413 Chinese students, 418 Latvian students and 428 Native Americans. To develop ethnic group-specific DAI equations these ratings were linked by regression procedures to the occlusal trait measurements available for each of the 200 stimuli. Using these equations, group-specific DAI scores were calculated for the 200 stimuli. At all levels on the DAI scale the percentage agreements, sensitivities and specificities ranged from 73 to 100 per cent indicating that the Standard DA can be used without modification to calculate DAI scores among Chinese, Latvians and Native Americans.
Adolescent↗
Role of tumor necrosis factor in neonatal sepsis.
In order to assess the role of tumor necrosis factor (TNF) in neonatal sepsis, plasma TNF levels were determined by a method using L929 cells at the time of septic work-up in 67 neonates. Thirty-three patients with sepsis were found to have significantly higher TNF levels (533.33 +/- 468.74 U/ml; 1 U corresponding to 1.67 pg recombinant TNF) as compared with 34 non-sepsis patients (100.0 +/- 188.97 U/ml) and 30 healthy newborns (27.33 +/- 16.17 U/ml, P < 0.05, respectively). The upper limit of normal plasma TNF levels was 60 U/ml and the best cutoff value for predicting neonatal sepsis was 160 U/ml. This had remarkable sensitivity (88%), specificity (82%), positive predictive value (83%), and negative predictive value (88%). Plasma TNF levels were significantly associated with the occurrence of shock, organ failure, scleroma and outcome. Thus, anti-TNF antibodies might be used in protecting newborns from septic death.
Acinetobacter Infections↗
Action of toosendanin on the membrane current of mouse motor nerve terminals.
By perineurial recording, the actions of toosendanin on three potassium currents and two calcium currents in the nerve terminal were observed in the intercostal nerve triangularis stein muscle of the mouse. Toosendanin partially blocked the voltage-dependent fast K+ current and irreversibly increased the voltage-dependent slow Ca2+ current. The increase in the Ca2+ current of the nerve terminal accounts for the facilitation of transmitter release and the antibotulismic effect of toosendanin.
Animals↗
Morphology and ordering in thin liquid-crystal films on flat glass substrates.
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Journal Article↗
Pedicle morphology of the lower thoracic and lumbar spine in a Chinese population.
Knowledge of pedicle diameter and surface landmarks is crucial for safe placement of screws. Little attention has been paid to variations of entrance points for pedicle screws, differentiation of male and female pedicle sizes and pedicle size differences in nonwhite populations. Forty thoracolumbar spinal columns from T9 to L5 were measured using vernier calipers. Cephalad-caudad and medial-lateral diameter of the pedicle, length of the pedicle from posterior cortex to anterior cortex at the midline and parallel to midline was measured. Relation of the centre of the pedicle to the transverse process (TP) and to the superior facet joint was noted. Twenty-five male and 15 female specimens were measured. Average pedicle width in the female was 5.2 mm at T9 (SD 0.9) to 13 mm at L5 (SD 2.7) and in the male 6.0 mm at T9 (SD 1.1) to 12.8 mm at L5 (SD 2.7). Cephalad caudad diameter was 12.5 mm (SD 1.2) at T9 to 20.5 mm (SD 3.6) at L5 in the male and in the female 12.2 mm (SD 1.3) at T9 to 18.7 mm (SD 3.9) at L5. All specimens had starting points cephalad to the midpoint of the TP at T9. At L5, 37 of 40 specimens had starting points at the midpoint of the TP. Starting points were parallel to the middle or lateral third of the superior facet joint at T9. At L5 starting points were at least one third of the facet joint lateral to the lateral border of the facet. Female pedicle width was smaller than male at T9 (P = 0.03) and T12 (P = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)
Asian People↗
A rapid, multiwell colorimetric assay for chemotaxis.
This paper describes a colorimetric assay for the rapid quantification of chemotaxis in multiple samples. In this assay, cells that have migrated through polycarbonate membrane filters are collected onto the bottom wells of a chemotaxis chamber after centrifugation then the number of viable cells collected in the bottom well is quantified by measurement of the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenol tetrazolium bromide (MTT). The degree of MTT reduction, which corresponds to the relative cell number, is measured automatically with an ELISA reader. The MTT method of quantitation is as sensitive as the standard manual method, is especially useful for large numbers of samples and requires no specialized laboratory equipment.
Animals↗