Fluctuations and entropy indices of QCD parton showers.
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Journal Article↗
Biomedical subjects
Z Cao
Publications and source records attributed to Z Cao.
The role of betagamma and alphagamma complexes in the assembly of human fibrinogen.
The role of alphagamma and betagamma dimers as intermediates in the assembly of fibrinogen was examined in cell fusion experiments using stably transfected baby hamster kidney cell lines expressing one or combinations of fibrinogen chains. Fibrinogen was readily formed and secreted into the culture media when cells co-expressing beta and gamma chains and generating betagamma complexes were fused with cells expressing only the alpha chain. Likewise, when cells co-expressing alpha and gamma chains and generating alphagamma complexes were fused with cells expressing only the beta chain, fibrinogen was also formed and secreted. The relative amounts of alphagamma or betagamma intermediates observed during fibrinogen biosynthesis were determined by the levels of the component chains; i.e. when the beta chain was limiting, the alphagamma dimer was the predominant intermediate; likewise, when the alpha chain was limiting, the betagamma complex was the predominant intermediate. The incorporation of preformed alphagamma and betagamma complexes into secreted fibrinogen did not require concurrent protein synthesis, as shown by experiments employing cycloheximide. These data strongly support the role of alphagamma and betagamma complexes as functional intermediates in the assembly of fibrinogen.
Animals↗
TRAF6 is a signal transducer for interleukin-1.
Many cytokines signal through different cell-surface receptors to activate the transcription factor NF-kappaB. Members of the TRAF protein family have been implicated in the activation of NF-kappaB by the tumour-necrosis factor (TNF)-receptor superfamily. Here we report the identification of a new TRAF family member, designated TRAF6. When overexpressed in human 293 cells, TRAF6 activates NF-kappaB. A dominant-negative mutant of TRAF6 inhibits NF-kappaB activation signalled by interleukin-1 (IL-1) but not by TNF. IL-1 treatment of 293 cells induces the association of TRAF6 with IRAK, a serine/threonine kinase that is rapidly recruited to the IL-1 receptor after IL-1 induction. These findings indicate that TRAF proteins may function as signal transducers for distinct receptor families and that TRAF6 participates in IL-1 signalling.
Amino Acid Sequence↗
A 50th order reaction predicted and observed for sickle hemoglobin nucleation.
Sickle hemoglobin polymerization exhibits a striking sensitivity to initial concentration, with characteristic reaction times that exhibit 30th power dependence on concentration. This extraordinary reaction order is encompassed by a novel double nucleation mechanism that predicts 50th power dependence of the homogeneous nucleation rate. Using a technique that allows individual homogeneous nucleation events to be monitored, we have measured a concentration dependence of 47+/-, in excellent agreement with the predictions of the model. Absolute nucleation rates agree with predictions as well.
Biopolymers↗
IRAK: a kinase associated with the interleukin-1 receptor.
The pleiotropic biological activities of interleukin-1 (IL-1) are mediated by its type I receptor (IL-1RI). When the ligand binds, IL-1RI initiates a signaling cascade that results in the activation of the transcription regulator nuclear factor kappa B (NF-kappa B). A protein kinase designated IRAK (IL-1 receptor-associated kinase) was purified, and its complementary DNA was molecularly cloned. When human embryonic kidney cells (cell line 293) over-expressing IL-1RI or HeLa cells were exposed to IL-1, IRAK rapidly associated with the IL-1RI complex and was phosphorylated. The primary amino acid sequence of IRAK shares similarity with that of Pelle, a protein kinase that is essential for the activation of a NF-kappa B homolog in Drosophila.
Amino Acid Sequence↗
NF-kappa B-mediated chromatin reconfiguration and transcriptional activation of the HIV-1 enhancer in vitro.
NF-kappa B is a potent inducible transcription factor that regulates many genes in activated T cells. In this report we examined the ability of different subunits of NF-kappa B to enhance HIV-1 transcription in vitro with chromatin templates. We find that the p65 subunit of NF-kappa B is a strong transcriptional activator of nucleosome-assembled HIV-1 DNA, whereas p50 does not activate transcription, and that p65 activates transcription synergistically with Sp1 and distal HIV-1 enhancer-binding factors (LEF-1, Ets-1, and TFE-3). These effects were observed with chromatin, but not with nonchromatin templates. Furthermore, binding of either p50 or p65 with Sp1 induces rearrangement of the chromatin to a structure that resembles the one reported previously for integrated HIV-1 proviral DNA in vivo. These results suggest that p50 and Sp1 contribute to the establishment of the nucleosomal arrangement of the uninduced provirus in resting T cells, and that p65 activates transcription by recruitment of the RNA polymerase II transcriptional machinery to the chromatin-repressed basal promoter.
Base Sequence↗
Phantom evaluation of simultaneous thallium-201/technetium-99m aquisition in single-photon emission tomography.
This study investigated downscatter effects in cardiac single-photon emission tomographic studies with simultaneous thallium-201/technetium-99m acquisition, and evaluated a previously proposed subtraction technique for downscatter compensation. Ten studies were carried out with different defect sizes and locations and varying activity distributions using four energy windows: 70+/-10% keV, 140+/-10% keV, 100+/-10% KeV, and 103+/-16% keV. The subtraction technique used the 100- or 103-keV data to remove scattered 99mTc counts from the 70-keV data. The size and contrast of infarcts in the dual-isotope 70-keV image were artificially decreased compared to those in the 140-keV image, caused by scattered 99mTc counts that were comparable to the primary 201Tl counts in the 70-keV window. The subtraction technique produced larger defects and more heterogeneous activity in the myocardial wall in dual-isotope 70-keV images compared to the corresponding 201Tl-only images. These artifacts were caused by the markedly different spatial distributions of scattered 99mTc counts in the 100-keV (or 103-keV) window as compared with the 70-keV window. It is concluded that scattered 99mTc photons may cause overestimation of ischemia and myocardial viability in simultaneous dual-isotope patient studies. The proposed subtraction technique was inaccurate and produced image artifacts. Adequate downscatter compensation methods must be developed before applying simultaneous 201Tl/99mTc acquisition in clinical practice.
Artifacts↗
A perfume odour-sensing system using an array of piezoelectric crystal sensors with plasticized PVC coatings.
Using PVC polymer as membrane matrix and di-n-octylphenyl phosphate (DOPP) as plasticizer, a piezoelectric crystal sensor (PCS) array with 12 adsorptive materials selected from 68 compounds by cluster analysis has been constructed as a perfume odour-sensing system. The frequency shift data obtained from the sensor array responding to four commercial perfume odours are first autoscaled and then treated by principal component analysis. The experimental results show that the plasticized PVC membrane PCS array provides improved performance of pattern recognition compared with the single adsorptive coating PCS array. The frequency shift response characteristics of these sensors have been investigated experimentally. The proposed sensor array has also been applied to the classification of commercial spirituous liquor, wine and soft drink samples, as well as aliphatic alcohol homologues and isomers.
Journal Article↗
The beta 1 sodium channel subunit modifies the interactions of neurotoxins and local anesthetics with the rat brain IIA alpha sodium channel in isolated membranes but not in intact cells.
Mammalian brain sodium channels consist of an alpha subunit and two smaller beta subunits. The role of the beta 1 subunit in modulating ligand interactions at these channels was examined using a cell line stably expressing human beta1 and rat brain IIA alpha subunits. Coexpression of the beta 1 subunit had no effect on the potencies of sodium channel blockers in inhibiting whole cell [3H]batrachotoxinin A benzoate ([3H]BTX) binding or veratridine-stimulated [14C]guanidinium influx. Coexpression of the beta 1 subunit also had no effect on the potencies of alpha scorpion toxin, brevetoxin, or RU 39568 in stimulating [14C]guanidinium influx. By contrast, coexpression of the beta 1 subunit had dramatic effects on ligand interactions in isolated membranes. In isolated membranes of cells expressing only the alpha subunit, the neurotoxins had no stimulatory effect on [3H]BTX binding and the potencies of local anesthetic-like channel inhibitors were 10-100-fold lower than those at native sodium channels. Whereas in membranes of cells coexpressing the beta 1 subunit, the neurotoxins increased [3H]BTX binding 30-fold and the potencies of the sodium channel inhibitors closely matched those found at native sodium channels. These findings indicate that the beta 1 subunit is not required for the binding of sodium channel activators or inhibitors but rather, that the beta 1 subunit may stabilize the alpha subunit in a functional conformation thereby allowing detection of these interactions in disrupted membranes.
Anesthetics, Local↗
Vascular hypertrophy and albumin permeability in a rat model combining hypertension and diabetes mellitus. Effects of calcium antagonism, angiotensin converting enzyme inhibition, and angiotensin II-AT1-receptor blockade.
The aim of this study was to compare the effects of angiotensin converting enzyme (ACE) inhibition, angiotensin II (AII) AT1-receptor blockade, and dihydropyridine calcium antagonism on hypertrophy and on vascular albumin permeability in kidney, heart, and mesenteric artery in a model combining genetic hypertension and diabetes mellitus. Diabetes mellitus was induced by streptozotocin in 8-week-old spontaneously hypertensive rats. The animals were randomized to receive no treatment, the angiotensin converting enzyme inhibitor ramipril, the AII AT1-receptor blocker valsartan, or the dihydropyridine calcium antagonist lacidipine for 3 weeks. Vascular albumin permeability was measured as the tissue content of intravenously injected Evans blue dye (EB) in kidney, heart, and mesenteric artery and the tissue/plasma EB ratio was calculated. Systolic blood pressure was reduced by all three antihypertensive regimens. Glycemic control was similar in all diabetic groups. Kidney hypertrophy was not affected by any of the antihypertensive drugs. Hypertrophy of the mesenteric artery was enhanced by lacidipine but was not affected by ramipril or valsartan. Relative heart weight was also increased by lacidipine. Vascular albumin permeability, expressed as EB content in micrograms/gram dry weight or as tissue/plasma EB ratio, was higher in the kidneys of lacidipine-treated rats than in any other group of diabetic rats. There was a positive correlation between kidney weight/body weight and kidney/plasma EB ratio in the diabetic rats. These findings indicate that the dihydropyridine calcium antagonist lacidipine is associated with an unfavorable effect on vascular hypertrophy and on vascular albumin permeability in the kidneys in rats with hypertension and diabetes mellitus. Furthermore, there seems to be a coupling in the diabetic kidney between hypertrophy and increased vascular albumin permeability.
Analysis of Variance↗
Quark-hadron phase transition with surface fluctuations.
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Journal Article↗
Chaotic behavior of particle production in branching processes.
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Journal Article↗
Optimal number of views in 360 degrees SPECT imaging.
UNLABELLED: This study examined SPECT-reconstructed image quality as a function of the number of views, and determined the minimum number of views necessary to remove aliasing artifacts in 360 degrees SPECT. METHODS: Computer simulation was performed using a two-dimensional Shepp-Logan head phantom and a high-resolution parallel-beam collimator with and without photon attenuation. RESULTS: In 360 degrees SPECT, aliasing artifacts were reduced by changing the number of views from an even number 16 to its neighboring odd numbers 15 or 17, from 32 to 31 or 33 and from 64 to 63 or 65. Image quality of 15 or 17 views, 31 or 33 views and 63 or 65 views was similar to that of 32, 64 and 128 views, respectively. CONCLUSION: Replacing an even number of views by its neighboring odd numbers in 360 degrees SPECT significantly decreased aliasing artifacts. Thirty-one or 33 views are sufficient to remove most of the aliasing artifacts in 360 degrees SPECT with a matrix of 64 x 64 pixels. This method can be applied to fast 360 degrees SPECT since fewer views are used.
Artifacts↗
Comparison of continuous step-and-shoot versus step-and-shoot acquisition SPECT.
UNLABELLED: This study compared the quality of SPECT images obtained with step-and-shoot mode (SSM) and continuous step-and-shoot mode (CSSM). METHODS: Computer simulations of SSM and CSSM were performed with a two-dimensional Shepp-Logan head phantom and a high-resolution parallel-hole collimator. The effects of noise and photon attenuation were examined. RESULTS: Without noise and without attenuation, small structures in reconstructed images obtained using fast CSSM (less than 4 sec per view plus the moving time from one view to the next) were slightly blurred and rotated in the opposite direction of detector motion. With both noise and attenuation, these artifacts were not visible, and the image quality obtained from CSSM, especially from fast CSSM, was improved as compared to that resulting from the corresponding SSM due to the increasing number of counts. The improvement of image quality became less significant with increasing acquisition time and in the presence of attenuation. CONCLUSION: For fast SPECT, CSSM provided better image quality than the corresponding SSM, especially when attenuation effects were not present. For relatively long time SPECT without attenuation compensation that is typical for clinical studies, the image quality of CSSM was similar to that of SSM.
Computer Simulation↗
[Standardization in the treatment of gynecologic malignancies should be emphasized].
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Female↗
[Monoclonal antibodies to human progesterone receptors: production, indentification and clinical application].
A peptide with 15 amino acid of human progesterone receptor (PR) was synthesized and used as antigen. Five hybridoma cells were obtained by cloning technique. In tests to hybridoma cell H4, the site specificity of the antibody to PR was found. The antibody reacted specifically with PR, but did not cross-react with ER, AR, or GR. Five women who used clomiphene citrate (CC) 100mg/d x 5 days were involved in a study of serum pregesterone (P) and endometrial histology in early luteal phase. There was no difference in serum P level in two groups. Three cases in CC group showed abnormal secretory endometrium. PR concentration in the nuclei of glandular cells of endometrium in CC group was significantly lower than that in the control group. In women with abnormal secretory endometrium, PR concentration in the nuclei of glandular cells was lower than that in women with normal endometrial histology. CC can influence endometrial histology by changing-PR concentration in the nuclei of glandular cells. The endometrium can not respond to the stimulus of P at normal levels and thus results in luteal phase defect.
Animals↗
A one-hand operation gun for transrectal prostate biopsy.
OBJECTIVE: To develop a new automatic biopsy device (ABD) that enables a radiologist to obtain multiple samples with one hand and free the other hand to handle the ultrasonic scanner for continuous monitoring. MATERIALS AND METHODS: The new ABD developed by us in April 1994 enabled a radiologist to complete all the biopsy procedures including loading and reloading the spring system, firing the device, emptying the specimen, selecting the depth of needle advancement, and multiple sampling, simply by pressing 3 buttons in turn with his/her right thumb. Using this new ABD, transrectal prostate biopsy under the guidance of transrectal ultrasonic imaging was performed in 60 consecutive cases of prostate diseases. Each biopsy procedure was completed by a single radiologist, who was able to obtain multiple specimens with one biopsy needle, using only one hand and freeing the other hand for the manipulation of the ultrasonic scanner for guidance. RESULTS: A total of 265 satisfactory core tissue specimens of 285 needle passes (93%) were obtained from the 60 patients. Definite pathologic diagnoses were made for all the 60 patients (100%). No serious biopsy-related complications were observed. The main complications were hematuria in 24 of 60 (40%) patients and fever in 5 (8.3%). CONCLUSION: On the basis of our experience with the 60 patients, this new ABD can be operated smoothly and effectively with the right hand, while the left hand is freed to handle the ultrasonic transducer for continuous monitoring.
Biopsy, Needle↗
[Persistent and recurrent gynecologic malignant tumor treated within one year: analysis of 1,753 cases from 61 hospitals in China].
OBJECTIVE: To analyze the causes of persistent and recurrent gynecologic malignant tumors treated within 1 year. METHODS: 20,974 cases of gynecologic malignant tumors from 61 hospitals in 24 provinces admitted between 1983-1993 were collected. Out of the total, 1753 cases treated within 1 year with tumor persistence, recurrence or death were retrospectively analysed. RESULTS: The ovarian carcinoma and vaginal cancer had the highest rates of tumor persistence, recurrence or death. Among the 1587 cases of tumor persistence or recurrence, pathological grading were not performed in 56.52% of the cases. For surgical treatment, inappropriate operation were done in 81.68% (767/939) of the ovarian carcinoma, 64.38% (103/160) of the cervical carcinoma, and 70.08% (89/127) of the endometrial cancer. 55.47% (532/959) of ovarian cancer and 38.31% (59/154) of choriocarcinoma and malignant mole had insufficient chemotherapy. For cervical cancer, 54.90% (235/396) of the cases did not receive enough doses of radiotherapy. CONCLUSION: Accurate staging and standardized therapy are important for improving 1 year survival rate in malignant gynecologic tumors.
Choriocarcinoma↗