Intensity-dependent scattering rings in high order above-threshold ionization.
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Journal Article↗
Biomedical subjects
B Yang
Publications and source records attributed to B Yang.
Comparison between thermoluminescence and cathodoluminescence spectra of KBr and KCl.
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Journal Article↗
Identification of two hyaluronan-binding domains in the hyaluronan receptor RHAMM.
We have identified two discrete hyaluronan- (HA) binding domains in the HA receptor RHAMM (Receptor for HA-Mediated Motility) that mediates the locomotion of H-ras transformed fibroblasts. A complete RHAMM cDNA (1.43 kilobases (kb)) was expressed as a fusion protein with pGEX-2T in Escherichia coli HB101 and was shown to bind specifically to both biotin-labeled HA in a transblot assay and to HA-Sepharose. The complete cDNA was truncated with restriction endonucleases from the 3' end resulting in 1.30-, 1.02-, 0.71-, and 0.41-kb cDNAs which were then expressed in HB101. Only the fusion peptide expressed from the complete cDNA and the 1.30-kb cDNA bound to HA indicating that the region located between 1.02-1.30 kb of RHAMM cDNA was critical for recognition of this glycosaminoglycan. Deletion of 114 bases in this region virtually eliminated HA binding activity thus defining the major glycosaminoglycan binding region to amino acids 400-434 located near the carboxyl terminus of RHAMM. Two domains containing clusters of basic amino acids were identified within this region. Synthetic peptides mimicking these two domains both inhibited HA binding to the complete 1.43-kb expressed glutathione s-transferase-RHAMM fusion protein, and also directly bound to HA-Sepharose. Random peptides and peptides mimicking other regions in RHAMM did not inhibit HA-RHAMM interactions and bound weakly to HA-Sepharose. Oligonucleotides encoding either of these two peptides were linked to the NH2-terminal 0.71 kb of RHAMM which encoded a peptide that did not contain HA binding activity. Fusion proteins containing either of these recombinant peptides acquired HA binding activity as assessed with a transblot assay. Thus, we have identified two domains within RHAMM that are responsible for its HA binding activity.
Amino Acid Sequence↗
Role of oligosaccharides in the processing and function of human transferrin receptors. Effect of the loss of the three N-glycosyl oligosaccharides individually or together.
When the coding sequence for human transferrin receptors was expressed in a Chinese hamster ovary cell line lacking endogenous transferrin receptors, 86-kDa molecules containing three N-glycosidically linked oligosaccharides were synthesized. These rapidly dimerized to form 172-kDa molecules which increased in size to 190 kDa. After site-directed mutagenesis of all three N-glycosylation sites, 80-kDa receptors were synthesized and only a few dimers were formed. 84-kDa monomers were synthesized in the absence of the oligosaccharide attached to Asn727 or Asn317. Dimerization and maturation through the Golgi body of the Asn727 mutant receptors were much slower than the wild type whereas the Asn317 mutant receptors behaved more similarly to the wild type. Lack of the oligosaccharide at Asn251 gave rise to 73-kDa monomers because of proteolytic processing (Hoe, M. H., and Hunt, R. C. (1992) J. Biol. Chem. 267, 4916-4923), but a second mutation at a potential cleavage site allowed the formation of 84-kDa receptors. These also dimerized at a similar rate to wild type receptors. The three-site mutant receptors were degraded in the endoplasmic reticulum but all three 84-kDa single site mutant receptor species migrated to the cell surface. However, receptors lacking the oligosaccharide at Asn727 bound and internalized little transferrin as a result of reduced affinity.
Animals↗
Above threshold ionization beyond the high harmonic cutoff.
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Journal Article↗
The effect of domestic and economic stress on suicide rates in Canada and the United States.
The study of the variation in societal suicide rates still is guided primarily by Durkheim's (1897) theory. He proposed primarily a social integration/regulation theory of suicide. One useful way of exploring this theory is from a cross-cultural perspective. Rates of birth, divorce, marriage, and unemployment were analyzed in comparison to rates of suicide from 1950 to 1985 in Canada and the United States. Results generally supported Durkheim's theory except for marriage. There was no association between marriage and suicide in Canada, whereas in the United States marriage had a protective effect once other variables were taken into account. Divorce rates were associated positively and birth rates associated negatively with suicide in both countries. Unemployment rates added little predictive power to suicide rates. A historical perspective and caution about overgeneralizing the results are presented.
Birth Rate↗
Quantitative polymerase chain reaction by monitoring enzymatic activity of DNA polymerase.
Nucleic acid amplification by polymerase chain reaction (PCR) is a very powerful technique in terms of sensitivity but is limited in terms of ability to perform accurate quantitation. While there is a theoretical correlation between copies of input target sequence and those of PCR product, the quantitative nature of this relationship is obscured by unpredictable variations in reaction conditions and by inhibitory and/or stimulatory substances which might be present in sample preparations, especially those derived from biological fluids. To reliably estimate copies of input DNA target from PCR product, we designed a combination of internal and external control systems coupled to DNA/RNA hybridization and enzymatic immunodetection techniques. The internal control system served to monitor amplification efficiency and to correct for the effects of inhibitors or stimuli on the efficiency of the DNA amplification. The assay is quantitative, nonisotopic, and can be widely applied to assessment of the quantity of DNA present in a wide range of preparations.
Base Sequence↗
Quantitative measurement of nonisotopically labeled polymerase chain reaction product.
A novel approach for evaluation of polymerase chain reaction product was described. A biotin-labeled DNA (or RNA) probe is hybridized to the digoxigenin-labeled target PCR product. The hybrids are retained on an anti-biotin antibody-coated plate. An anti-digoxigenin Fab conjugated with alkaline phosphatase is used for generating either a fluorescence or a chromagenic substance. Both fluorogenic and chromagenic systems can be used for quantitative measurement of the PCR product/probe hybrids. The method is specific, fast, nonisotopic, sensitive, quantitative, and practical.
Base Sequence↗
A microsatellite-based multipoint index map of human chromosome 22.
Utilizing the CEPH (Centre d'Etude du Polymorphism Humain) reference panel and genotyping data for 24 simple tandem repeat polymorphism (STRP) markers, we have constructed a 15-locus multipoint genetic framework map of human chromosome 22. The markers form a continuous linkage group of 51 cM in males and 81 cM in females. Likely genetic locations are provided for 9 additional STRP sequences. The map was constructed employing the CRIMAP computational methodology to build the multipoint map via a stepwise algorithm. The quality of the framework map was evaluated using a battery of statistical diagnostics that suggest a typing error frequency of 0.1% for markers within the map.
Base Sequence↗
Verapamil and aspirin modulate platelet-mediated vasomotion in arterial segments with intact or disrupted endothelium.
OBJECTIVES: This study was designed to examine the effects of verapamil and aspirin, which decrease thromboxane A2 and serotonin release, on the modulation of vascular tone by platelets. BACKGROUND: Aggregating platelets cause constriction of de-endothelialized arterial segments through thromboxane A2 and serotonin release. These cells cause relaxation of arterial segments with intact endothelium through release of the endothelium-derived relaxing factor. METHODS: Healthy subjects were given either no drug, verapamil or aspirin for > or = 5 days before their platelets were obtained. The effects of platelets obtained from subjects before and after treatment with aspirin or verapamil on the tone of rat aortic rings were determined. RESULTS: As expected, control platelets (before verapamil or aspirin treatment) induced concentration-dependent relaxation of rat aortic rings with intact endothelium and a concentration-dependent contraction of de-endothelialized rings. Verapamil treatment enhanced (p < 0.02) the platelet-mediated relaxation in rings with intact endothelium and abolished platelet-mediated constriction (p < 0.01) in the de-endothelialized rings. Aspirin treatment also abolished (p < 0.05) platelet-mediated constriction of the de-endothelialized rings. The de-endothelialized rings contracted normally in response to the synthetic thromboxane A2 analogue U46,619, as well as to serotonin, indicating that the vascular smooth muscle response to thromboxane A2 and serotonin was intact. CONCLUSIONS: This study provides evidence for the modulation of platelet-mediated vasoconstriction of de-endothelialized arterial segments by prior treatment of subjects with verapamil or aspirin. In clinical syndromes characterized by endothelial dysfunction or disruption, treatment with verapamil or aspirin may modify platelet-vessel wall interactions.
Animals↗
Human dystroglycan: skeletal muscle cDNA, genomic structure, origin of tissue specific isoforms and chromosomal localization.
Dystroglycan is a novel laminin binding component of the dystrophin-glycoprotein complex which provides a linkage between the subsarcolemmal cytoskeleton and the extracellular matrix. Here we report the cDNA and genomic structure of human dystroglycan. The human dystroglycan is encoded by a single gene (DAG1) mapped to chromosome 3 band p21. The coding sequence is organized into two exons, separated by a large intron. The predicted amino acid sequence of human and rabbit dystroglycan are 93% identical with predicted glycosylation sites being conserved. Human dystroglycan is expressed in a variety of fetal and adult tissues. Our data suggest that muscle and non-muscle isoforms of dystroglycan differ by carbohydrate moieties but not protein sequence. Therefore, we hypothesize that variable glycosylation of the conserved protein core might modulate laminin binding. The relationship of dystroglycan to human diseases is discussed.
Amino Acid Sequence↗
Dietary fish oil supplementation attenuates myocardial dysfunction and injury caused by global ischemia and reperfusion in isolated rat hearts.
To determine the effect of dietary fish oil supplementation on myocardial dysfunction following ischemia-reperfusion, independent of plasma and blood cells, Sprague-Dawley rats were fed fish oil-rich nonpurified diet or butter-enriched diet for 5 d. Myocardial content of long-chain and (n-3) polyunsaturated fatty acids was greater in the fish oil-fed rats (P < 0.01), whereas (n-6) fatty acid content was lower compared with controls (P < 0.01). Platelet aggregation in fish oil-fed rats was also inhibited. Hearts from all rats were subjected to 15 min of global ischemia and 10 min of reperfusion. In hearts of control rats, ischemia-reperfusion resulted in a marked decrease in force of cardiac contraction, increase in coronary perfusion pressure, appearance of ventricular arrhythmias and release of creatine kinase and thromboxane B2 in the coronary effluent. Dietary fish oil supplementation attenuated myocardial dysfunction induced by ischemia-reperfusion, as indicated by smaller change in force of cardiac contraction (-77% vs. -89%, P < 0.05) and coronary perfusion pressure (+37% vs. +71%, P < 0.001). Concomitantly, release of creatine kinase as well as thromboxane B2 in coronary effluent was lower (P < 0.01). Ventricular arrhythmias occurred less frequently in hearts from fish oil-fed rats. Thus, short-term dietary fish oil supplementation attenuates myocardial dysfunction caused by ischemia-reperfusion by a direct effect on the heart independent of blood and plasma components.
Analysis of Variance↗
Double ionization in the perturbative and tunneling regimes.
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Journal Article↗
Identification of hyaluronan binding proteins using a biotinylated hyaluronan probe.
A method for detecting hyaluronan (HA)-binding proteins in transblot assays using biotinylated HA (BHA) is described. Some of the binding characteristics of a novel HA receptor termed RHAMM (Receptor for HA-Mediated Motility) are characterized using this assay. The method is also used to detect other HA-binding proteins in tissue homogenates. This method is semiquantitative, rapid, reproducible, sensitive and therefore of potential use in identifying the levels of HA-binding proteins in different cells and tissues.
Animals↗
[The role of substance P and somatostatin in acupuncture and moxibustion-induced postsynaptic inhibition].
AIM OF INVESTIGATION: Our previous work indicated that acupuncture and moxibustion (heating acupoints with a special lamp) could produce inhibitory effects on the tail flick reflex and the nociceptive response of dorsal horn neurons. In the present study the role of somatostatin (SS) and substance P (SP) in acupuncture and moxibustion-induced postsynaptic inhibition was further investigated. METHODS: The experiments were performed on male adult Wistar rats. The antidromic action potential (AAP) induced by cervical cord stimulation was extracellulary recorded at lumbar cord (L3-4). The latency of AAP was used to represent the excitability of postsynaptic projecting neurons. The effects of acupuncture (0.5 ms, 3.3 Hz, 2 mA) for five minutes or moxibustion (the temperature up to 45-46 degrees C) for six minutes at Huantiao points on the latency of AAP were observed. And then the effects of topical administration of SS or SP antiserum on either acupuncture or moxibustion-induced postsynaptic inhibition were observed. RESULTS: The latency of AAP was markedly prolonged by acupuncture and moxibustion. The maximal prolongation was 0.196 +/- 0.071 ms (n = 12, P < 0.02) and 0.176 +/- 0.062 ms (n = 11, P < 0.02) respectively. After topical administration of SS antiserum (1:40, 10 microliters), the latency of AAP was slightly prolonged by either acupuncture or moxibustion. The maximal prolongation (0.041 +/- 0.029 ms and 0.016 +/- 0.020 ms) was significantly reduced by SS antiserum (P < 0.05). While pretreated with SP antiserum, the latency was still prolonged by moxibustion (0.142 +/- 0.067 ms), but not by acupuncture (-0.003 +/- 0.046 ms). CONCLUSION: It is referred that postsynaptic inhibition may be involved in both acupuncture analgesia and moxibustion analgesia. The former is predominately mediated by SP and partially by SS, while the latter mainly by SS but not by SP.
Action Potentials↗
[Evidences for the appearance of peripheral activator during the advance of PSM].
Investigation on mechanism underlying the formation of the propagated sensation along meridians (PSM) is one of the important problems in meridian research. In order to interpret the problem more satisfactorily, we had advanced a hypothesis in 1987, that is, 'integration of periphery' and CNS under the domination of substantial process proceeding along the meridians". According to this hypothesis, "periphery" and "central mechanism" are operated as a whole. However, it also emphasized that the peripheral substantial process is the determinant factor in the formation of PSM. And then, is there really a peripheral substantial process, or, in other word, a peripheral activator during the advance of PSM. The afferent discharges were directly led from the superficial branch of radial nerve. Nineteen volunteers with marked PSM were under observation. The preliminary results demonstrated that as PSM, evoked by stimulating Jianyu (LI15) or Ying Xiang Acupoint (LI20), travelled along the course of Large Intestine Meridian to the hand or index finger, the corresponding afferent impulses could be recorded from that nerve branch in a part of experiments. Through a series of control observations, it has been proved that the impulses recorded was not resulted from other responses, but really the afferent impulse discharged by the neuroreceptor apparatus distributing along the meridian, which was activated by certain stimulation. The facts demonstrated that "the peripheral activator" really appeared during the advance of PSM. It is of significance for the investigation on the mechanism underlying the formation of PSM.
Acupuncture Points↗
[Observation on the functional characteristics of cortical somatosensory area during the advance of the propagated sensation along meridians].
It is still not clear what role is played by cortical somatosensory system during the advance of propagated sensation along meridians (PSM). In this paper the short-latent somatosensory evoked potential (SLSEP) was taken as an indication to observe the characteristics of functional activity in cortical somatosensory area I (SI) during the advance of PSM. The observation was preformed on 10 subjects with marked PSM, which were clear and kept stable. Sixteen subjects without SPM were taken as control. Electrical stimulation was delivered to the acupoint Jiaxi (GB43) or Hegu (LI4). The SLSEP were recorded simultaneously from 3 scalp points corresponding to the representative areas of foot, arm and face contralateral to the stimulated side. The results are shown as follows. When Jiaxi was stimulated, the amplitudes of SLSEP component C2 (P45-N55) from above three scalp points in subjects without PSC were 0.85 +/- 0.17, 0.51 +/- 0.11 and 0.31 +/- 0.07 microv respectively. The amplitude was largest in the foot representative area, but attenuated successively in arm and face areas and a stair-shaped distribution was thus formed. During stimulating the acupoint Hegu (LI4) the amplitude of SLSEP component C2 (P25-N55) from the representative area of arm in subjects without PSM was larger than that from the representative areas of foot and face, and a distribution with high-medium and low-bilateral character was shaped. However, no matter whether stimulating Jiaxi or Hegu the amplitude of SLSEP C2 in subjects with marked PSM was nearly the same from three scalp points.(ABSTRACT TRUNCATED AT 250 WORDS)
Acupuncture Points↗
[Localization of the meridian track over body surface by the method of blocking the acupuncture effect with mechanical pressure].
Plotting out the meridian course with objective methods is one of the important projects in the research of meridian at present. Therefore, selecting a proper indication to plot out the meridian track over the body surface during acupuncture is significant for elucidating the essence of meridian. The purpose of this paper was to plot out the Large Intestine Meridian track by blocking the acupuncture effect with mechanical pressure, when electroretinogram (ERG) was taken as a responsive indication. The plotting out the track was carried out on 5 subjects with marked propagated sensation along meridians (PSM) and 5 without PSM. The pressure was applied on Wenliu (LI 7), Shoushanli (LI 10), Quchi (LI 11), Binao (LI 14) and Jianyu (LI 15) respectively, when Hegu (LI 4) was punctured. Under such condition the variation of ERG amplitude decreased markedly or even disappeared. But the variation rate of ERG amplitude was still distinctly increased when the pressure was applied on both sides of any above points. The difference is highly significant (P < 0.01). The results revealed that the meridian track over the body surface during acupuncture could be plotted out not only in the subjects with marked PSM, but also in those without PSM, when the proper objective indication was used. Its course basically coincided with that of the meridian described in the books of traditional Chinese medicine. Now it is safe to say the meridian track over the body surface is existed in human in common. It provides a new approach to plot out the meridian course with objective methods and opens up broad prospects for further application.
Acupuncture Points↗