Protein-protein interactions probed by nuclear magnetic resonance spectroscopy.
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Binding Sites↗
Biomedical subjects
J Qin
Publications and source records attributed to J Qin.
Semiparametric analysis of truncated data.
Randomly truncated data are frequently encountered in many studies where truncation arises as a result of the sampling design. In the literature, nonparametric and semiparametric methods have been proposed to estimate parameters in one-sample models. This paper considers a semiparametric model and develops an efficient method for the estimation of unknown parameters. The model assumes that K populations have a common probability distribution but the populations are observed subject to different truncation mechanisms. Semiparametric likelihood estimation is studied and the corresponding inferences are derived for both parametric and nonparametric components in the model. The method can also be applied to two-sample problems to test the difference of lifetime distributions. Simulation results and a real data analysis are presented to illustrate the methods.
Acquired Immunodeficiency Syndrome↗
Avoiding premature apoptosis of normal epidermal cells.
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Apoptosis↗
Macrophage-derived chemokine expression in classical Hodgkin's lymphoma: application of tissue microarrays.
Hodgkin's disease (HD) is a lymphoid malignancy characterized by the presence of Reed-Sternberg (RS) and Hodgkin's cells in a background of mixed inflammatory cells and stromal reaction. Studies have documented that HD is a neoplasm associated with abnormal cytokine and chemokine production. To define the expression of macrophage-derived chemokine (MDC) in HD, 57 cases (18 lymphocyte predominant, 11 mixed cellularity, 28 nodular sclerosis) were stained for MDC by immunohistochemistry and compared with reactive lymph nodes as controls. MDC was expressed by RS cells in classical HD (CHD) and showed a distinct cytoplasmic and Golgi localization. Accumulating evidence suggests that lymphocyte-predominant HD (LPHD) represents an entity distinct from CHD, with different biological properties and clinical course. On the basis of the high level of MDC staining alone, CHD could be distinguished from LPHD (P <.001), which showed only faint staining of scattered histiocytes similar to control tissues. CHD cases with high MDC mRNA levels showed high levels of MDC protein expression by immunohistochemistry (P <.001) and significant eosinophil infiltration, suggesting that MDC may represent another molecule that plays a critical role in eosinophil recruitment. We also analyzed 102 cases of non-Hodgkin's lymphoma and normal spleen, lymph node, and thymic tissue. High levels of MDC expression were specific to CHD cases because only low levels of MDC were observed in a minor subset of LPHD, NHL or normal lymphoid tissues.
Adolescent↗
Branched nanowire based guanine rich oligonucleotides.
Self-assembly and aggregation of guanine rich sequences can provide useful insights into DNA nanotechnology and telomeric structure and function. In this paper, we designed a guanine rich sequence d(GGCGTTTTGCGG). We found that it can form stable structure in appropriate condition and it exhibits an anomalous CD spectra. This structures can be imaged in ambient environment with a Nanoscope III AFM (Digital Instruments). We found it forms branch structure and long multistrand DNA nanowire after incubation at 37 degrees C for 6-12 hours in 25 mM TE (pH=8.0) + 5 mM Mg2+ + 50 mM K+. The ability to self-assemble into branches and long wires not only clearly demonstrate its potential as scaffold structures for nanotechnology, but also give aids to understand telomeric structure further. We have proposed a model to explain how these structures formed.
Circular Dichroism↗
Detection of early gene expression changes during activation of human primary lymphocytes by in vitro synthesis of proteins from polysome-associated mRNAs.
The rapid increase in protein synthesis during the mitogenic stimulation of human peripheral blood lymphocyte is the result of global and specific translational control mechanisms. To study some of these mechanisms, we examined the in vitro translatability of mRNAs associated with the polyribosome fraction. Polyribosome fractions were isolated from lymphocytes after activation with ionomycin and the phorbol ester PMA. The associated PAmRNAs were translated in the presence of mRNA-depleted rabbit reticulocyte lysate and [(35)S]Met, and the protein products were analyzed by SDS--PAGE and autoradiography. There was little synthesis of protein from the PAmRNAs isolated from unactivated T cells, but the PAmRNAs isolated from activated T cells showed a rapid increase in translatability. Translation of the PAmRNAs was sensitive to edeine and m7GTP, suggesting their cap-dependent translation. With activation, the majority of proteins showed increasing in vitro translation, but two proteins, p72 and p33, were found to have increased synthesis within 30 min, which decreased in 1 h. Transcription inhibitors were used to ascertain if regulation of their expression was transcriptional or translational. To identify these proteins, we used biotinylated lysine during the in vitro translation reaction, and we extracted the biotinylated protein by using streptavidin magnetic beads. The protein product was analyzed by mass spectrometry. p33 was identified as a prohibitin-like protein (BAP37), but the identification of p72 was not found in the databases. The distinct up-regulation and down-regulation of their protein expression suggest their tightly controlled regulation during early T cell activation.
Animals↗
Pairwise rank-based likelihood for estimation and inference on the mixture proportion.
We consider the problem of estimation and inference on the mixture parameter in the two-sample problem when sample data from the two distributions as well as from a third population consisting of a mixture of the two are used. Under a general nonparametric model, where the relationship between the two populations is unspecified, we develop a pairwise rank-based likelihood. Simultaneous inference on the mixture proportion and a parameter representing the probability an observation from one population is greater than an observation from the other population is based on this likelihood. Under some regularity conditions, it is shown that the maximum pairwise rank likelihood estimator is consistent and has an asymptotic normal distribution. Simulation results indicate that the performance of this statistic is satisfactory. The methodology is demonstrated on a data set in prostate cancer.
Biometry↗
Modular structure of PACT: distinct domains for binding and activating PKR.
PACT is a 35-kDa human protein that can directly bind and activate the latent protein kinase, PKR. Here we report that PKR activation by PACT causes cellular apoptosis in addition to PKR autophosphorylation and translation inhibition. We analyzed the structure-function relationship of PACT by measuring its ability to bind and activate PKR in vitro and in vivo. Our studies revealed that among three domains of PACT, the presence of either domain 1 or domain 2 was sufficient for high-affinity binding of PACT to PKR. On the other hand, domain 3, consisting of 66 residues, was absolutely required for PKR activation in vitro and in vivo. When fused to maltose-binding protein, domain 3 was also sufficient for efficiently activating PKR in vitro. However, it bound poorly to PKR at the physiological salt concentration and consequently could not activate it properly in vivo. As anticipated, activation of PKR by domain 3 in vivo could be restored by attaching it to a heterologous PKR-binding domain. These results demonstrated that the structure of PACT is modular: it is composed of a distinct PKR-activation domain and two mutually redundant PKR-interacting domains.
2',5'-Oligoadenylate Synthetase↗
Biologic role of fetal lung fibroblast triglycerides as antioxidants.
The pulmonary response to hyperoxia is highly variable, depending on such seemingly disparate biologic factors as gestational age, sex, hormonal milieu, and nutritional status. Descriptively, the magnitude and direction of these biologic differences in response to hyperoxia correlate with the triglyceride content of developing fetal rat lung fibroblasts (FRLFs). Mechanistically, these same factors affect the triglyceride content of FRLFs, e.g. d 21 FRLFs contain more triglyceride than d 18 FRLFs; female FRLFs contain more triglyceride than male FRLFs (d 20); dexamethasone increases FRLF triglyceride content, dihydrotestosterone decreases it; nutritionally, exposure of FRLFs to graded amounts of serum triglyceride (0%, 2%, 10%, 20%) results in increased intracellular FRLF triglyceride content. To test the hypothesis that these biologic differences in intracellular triglyceride content may account for differences in the cytoprotection of lung fibroblasts against oxidant injury, fibroblast cultures representing each of these biologic groups were challenged with graded doses of the reactive oxygen species hydrogen peroxide (0.1-1.0 mM for 5 min). The number of surviving cells and their antioxidant status, as measured by lipid peroxidation and glutathione content of the surviving cells, were determined. We found that in response to hydrogen peroxide 1) d 21 FRLFs were more resistant than d 18 FRLFs; 2) female FRLFs were more resistant than male FRLFs; 3) dexamethasone-treated FRLFs were more resistant than dihydrotestosterone-treated fibroblasts; 4) fibroblasts fed increasing amounts of serum triglycerides were increasingly resistant to hydrogen peroxide; 5) cell survival in different serum triglyceride- and hormone-treated groups was not related to the antioxidant status as measured by glutathione content. These data are consistent with the hypothesized role of FRLF triglycerides as antioxidants.
Animals↗
Molecular genetics of neuroblastoma and the implications for clinical management: a review of the MSKCC experience.
Neuroblastoma (NB) is a biological, genetic, and morphological heterogeneous neoplasm and demonstrates diverse clinical behavior. There exist at least three clinical patterns of NB: A) spontaneously regressing widespread disease; B) not metastatic local-regional disease, and C) metastatic disease (stage 4), frequently with lethal consequences. Patients with non-stage 4 NB are expected to survive even without medical treatment whereas stage 4 patients have an overall survival rate of 20% despite multimodality therapy protocols. The clinical management of patients with NB is therefore challenged by the objective identification of cases in which noncytotoxic approaches can be safely taken. Experience in the last decade at Memorial Sloan-Kettering Cancer Center supports the hypothesis that the natural history of disease defines relevant clinical groups of NB and has distinct molecular genetic profiles allowing therapeutic approaches tailored for each group. Here we review the natural history and clinicobiological features of 113 NB cases managed uniformly in our institution in an attempt to characterize useful genetic markers to support the decision making of noncytotoxic versus cytotoxic approaches for each category of NB.
Humans↗
Loss of heterozygosity at 19q13.3 is associated with locally aggressive neuroblastoma.
A genome-wide allelic analysis of neuroblastoma (NB) revealed a previously undescribed increased incidence of loss of heterozygosity (LOH) on chromosome arm 19q13 primarily affecting stages 3 and 4N disease. Further allelic analysis of chromosome 19q13 in a cohort of 116 NB patients using 17 polymorphic microsatellite markers identified the shortest common region of loss between D19S606 and D19S112 at 19q13.3. In some cases, clonal LOH at 19q13 was acquired during the course of disease, and deleted clones remained after cytotoxic therapy. In multivariant analysis, 19q13 LOH was associated with overall survival in local-regional International Neuroblastoma Staging System stages 1, 2, and 3 patients and was specifically present in tumors at the site of recurrence.
Chromosomes, Human, Pair 19↗
Source ROCs are (typically) curvilinear: comment on Yonelinas (1999).
On the basis of his assumption that recollection is a threshold process, A. P. Yonelinas (1999) predicted linear source-identification receiver operating characteristics (ROCs) and recently reported data that were consistent with this prediction. In this article, the authors present data showing curvilinear source-identification ROCs across various encoding and test conditions. On the basis of the source-monitoring framework (e.g., M. K. Johnson, S. Hashtroudi, & D. S. Lindsay, 1993), the authors argue that curvilinearity of source-identification ROCs is a result of differences in the qualitative characteristics of memories rather than simply the influence of undifferentiated familiarity as the dual-process model might suggest.
Adult↗
[Effects of surface pattern of polymers on adhesion characteristics of transformed human embryonic tendon cells].
Effects of surface pattern of polymers on adhesion characteristics of transformed human embryonic tendon cells (THETCs) have been examined by using a micropipette aspiration technique, which is a cellular mechanical method. The results showed that the adhesion characteristics of THETCs depend on the surface pattern of polymers, and the adhesion force of THETCs to porous films is higher than that to non-porous films and fibers. The adhesion force bears relationships with the aperture of porous films and has a stronger dependence on the large aperture (150-500 microns) than on the small aperture (< 150 microns) of porous films. The adhesion force of THETCs to fibers is increased slightly with the diameter of fibers (P > 0.05). These demonstrate that the tissue-engineered tendon scaffolds made of porous polymer foam with specially designated aperture, or of polymer fiber with specially designated diameter, may serve as a good attachment substrate for THETCs.
Biopolymers↗
Aortic and mitral valve replacement with retrograde perfusion in the beating heart.
OBJECTIVE: To estimate the value of aortic valves and combined mitral valve replacement with retrograde perfusion in beating hearts. METHODS: Continuous retrograde coronary sinus perfusion with beating hearts was used in 83 patients undergoing aortic valve or aortic valve combined with mitral valve replacement, without application of cardioplegia. After aortic valve replacement, the retrograde perfusion was changed to antegrade perfusion for mitral valve replacement or correction of the other deformities (group A). Cold blood cardioplegia solution (15 degrees C) was infused at intervals in 20 cases (group B). The following parameters were tested: lactate, ET, CTn-T and MDA in blood; myocardial ultra-structure; and cardiac rhythm and cardiac output (CO). RESULTS: All biochemical values increased after cardiopulmonary bypass (P < 0.05-0.01). Empty and beating heart sinus rhythm was maintained in group A. Myocardial ultrastructure did not change significantly. The pump was stopped smoothly as the surgical procedure finished. No postoperative low cardiac output syndrome or arrhythmia was observed. Eight-one patients recovered smoothly, two died from renal failure or infective shock. When the pump stopped, all patients in group B were supported by 5-10 micrograms.kg-1.min-1 dopamine. Transient pacing was used in 9 patients. One patient died from low cardiac output syndrome. CONCLUSION: This method is a good myocardial protection which simulates physiologic status. It is applicable to aortic valve and combined mitral valve replacement of patients with large heart or heart failure and long time aortic cross-clamping. Ideal clinical effect can be achieved.
Adolescent↗
Cell cycle analysis by cyclin E + A/DNA multiparameter flow cytometry in exponential growth MOLT-4 cells.
OBJECTIVE: To establish a new method for analyzing the cell cycle in tumor which is a kind of cell cycle disease. METHODS: Mixtures of cyclin E and cyclin A antibodies were incubated with fixed MOLT-4 cells, and measured by flow cytometry. RESULTS: We developed a cyclin E + A/DNA flow cytometry analysis method, which may distinguish G0, early G1, late G1, S, G2 and M phase cells, rather than three phases in the DNA content histogram. CONCLUSION: Cyclin E + A/DNA multiparameter flow cytometry can simultaneously differentiate in the same sample six cell groups: G0, early G1, late G1, S, G2 and M phase cells. It performed better than any other cell cycle analysis methods that we have used and has a definite cell biology foundation.
Cell Cycle↗
[Effect of hypertonic saline solution on the viscoelasticities of erythrocyte membrane in rats subjected to hemorrhagic shock].
We have studied the effect of hypertonic saline solution on the viscoelasticities of erythrocyte membrane in hemorrhage-shocked rats using micropippette aspiration technique. Wistar rats were randomly divided into three groups of 0.9% NaCl(NS), 7.5% NaCl (HS) and 5% NaCl-3.5% NaAc (HSA), respectively. The animals were bled to reach a mean arterial pressure of 5.3 kPa in 10 minutes and maintained in shock for 90 minutes. 4 ml/kg NS, HS and HSA was given intravenously and respectively in 5 minutes following hemorrhagic shock. The blood was collected to determine the viscoelasticities of erythrocyte membrane at baseline, shock and after treatment. The results showed that the elastic moduli and viscous coefficients of erythrocyte membrane were increased obviously following hemorrhagic shock. HS raised elastic moduli and reduced viscous coefficients significantly compared with NS after treatment. The elastic moduli and viscous coefficients of erythrocyte membrane were decreased remarkably in HSA group than in NS and HS group. These data suggested that HSA could improve the viscoelasticities of erythrocyte membrane significantly in rats subjected to hemorrhagic shock.
Animals↗
[Epidemiological observation on effect of Leptospiral outer membrane vaccine].
OBJECTIVE: To study the safety and effect of Leptospiral outer membrane vaccine. METHODS: Eighty thousands dosages of Leptospiral outer membrane vaccine were vaccinated in Jingzhou and Shishou city Hubei prevince. Temperaure, side-effects such as Local edema with in 48 hours as well as the incidence of Leptospirsis within a year among those were vaccinated and unvaccinated were observed. RESULTS: (1) No any severe side-effect and abnormal reaction, was found, only 2 case suffered from slight fever and local edema which receded in 48 hrs. (2) Effects of Leptospiral outer membrane vaccine were as follows: 2 cases were attacked by lacterohaemorrhagiae in vaccination group and 47 cases in control group, so the protection rate 95.57% and confidence interval (CI) was 85.43% - 98.20%. Fifteen hebdomadis cases were found in control group. The protection rate of this vaccine reached 100.00%, CI 77.08% - 100.00%. CONCLUSION: Safty and protective effect were well showed when type of bacteria was concordant with that in vaccination district.
Adolescent↗
[Microplate test of non-specific esterase detection for insecticide resistance of Culex pipiens pallens].
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Animals↗