PubMed Health⌕ Search

Biomedical subjects

Rong Zhu

Publications and source records attributed to Rong Zhu.

27 records · Page 2Linked to original sources
PubMed2005

Visualization of single receptor molecules bound to human rhinovirus under physiological conditions.

Dynamic force microscopy (DFM) was used to image human rhinovirus HRV2 alone and complexed with single receptor molecules under near physiological conditions. Specific and site-directed immobilization of HRV2 on a model cell membrane resulted in a crystalline arrangement of virus particles with hexagonal symmetry and 35 nm spacing. High-resolution imaging of the virus capsid revealed about 20 resolvable structural features with 3 nm diameters; this finding is in agreement with protrusions seen by cryo-electron microscopy. Binding of receptor molecules to individual virus particles was observed after injection of soluble receptors into the liquid cell. Virus-receptor complexes with zero, one, two, or three attached receptor molecules were resolved. The number of receptor molecules associated to virions increased over time. Occasionally, dissociation of single receptor molecules from viral particles was also observed.

Capsid↗
PubMed2004

Dynamic force microscopy for imaging of viruses under physiological conditions.

Dynamic force microscopy (DFM) allows imaging of the structure and the assessment of the function of biological specimens in their physiological environment. In DFM, the cantilever is oscillated at a given frequency and touches the sample only at the end of its downward movement. Accordingly, the problem of lateral forces displacing or even destroying bio-molecules is virtually inexistent as the contact time and friction forces are reduced. Here, we describe the use of DFM in studies of human rhinovirus serotype 2 (HRV2) weakly adhering to mica surfaces. The capsid of HRV2 was reproducibly imaged without any displacement of the virus. Release of the genomic RNA from the virions was initiated by exposure to low pH buffer and snapshots of the extrusion process were obtained. In the following, the technical details of previous DFM investigations of HRV2 are summarized.

Journal Article↗
PubMed2004

A real-time articulated human motion tracking using tri-axis inertial/magnetic sensors package.

A basic requirement in virtual environments is the tracking of objects, especially humans. A real time motion-tracking system was presented and evaluated in this paper. System sensors were built using tri-axis microelectromechanical accelerometers, rate gyros, and magnetometers. A Kalman-based fusion algorithm was applied to obtain dynamic orientations and further positions of segments of the subject's body. The system with the proposed algorithm was evaluated via dynamically measuring Euler orientation and comparing with other two conventional methods. An arm motion experiment was demonstrated using the developed system and algorithm. The results validated the effectiveness of the proposed method.

Acceleration↗
PubMed2004

Monitoring RNA release from human rhinovirus by dynamic force microscopy.

Human rhinoviruses were imaged under physiological conditions by dynamic force microscopy. Topographical images revealed various polygonal areas on the surfaces of the 30-nm viral particles. RNA release was initiated by exposure to a low-pH buffer. The lengths of the RNAs that were released but still connected to the virus capsid varied between 40 and 330 nm, whereas RNA molecules that were completely released from the virus were observed with lengths up to 1 micro m. Fork-like structure elements with 30-nm extensions were sometimes resolved at one end of the RNA molecules. They possibly correspond to the characteristic multi-stem-loop conformation, the internal ribosomal entry site, located at the 5' region of the genome. This study demonstrates that dynamic force microscopy can be used to study viral RNA release in situ under physiological conditions.

Capsid↗
PubMed2004

Imaging morphological details and pathological differences of red blood cells using tapping-mode AFM.

The surface topography of red blood cells (RBCs) was investigated under near-physiological conditions using atomic force microscopy (AFM). An immobilization protocol was established where RBCs are coupled via molecular bonds of the membrane glycoproteins to wheat germ agglutinin (WGA), which is covalently and flexibly tethered to the support. This results in a tight but non-invasive attachment of the cells. Using tapping-mode AFM, which is known as gentle imaging mode and therefore most appropriate for soft biological samples like erythrocytes, it was possible to resolve membrane skeleton structures without major distortions or deformations of the cell surface. Significant differences in the morphology of RBCs from healthy humans and patients with systemic lupus erythematosus (SLE) were observed on topographical images. The surface of RBCs from SLE patients showed characteristic circular-shaped holes with approx. 200 nm in diameter under physiological conditions, a possible morphological correlate to previously published changes in the SLE erythrocyte membrane.

Erythrocyte Membrane↗
PubMed2004

[Clinical study on treatment of mid-advanced crescentic nephritis by qingre huoxue recipe].

OBJECTIVE: To evaluate the therapeutic effect of integrative Chinese and Western medicine in treating mid-advanced crescentic nephritis (MACN). METHODS: Thirty-two patients, their diagnosis was confirmed as MACN by renal biopsy, were divided, adopting randomized, controlled method, into two groups, the treated group and the control group, they were all, excepting one, treated with impact therapy of methyl-prednisolone followed with oral intake of prednisone, to part of them cyclophosphamide or mycophenolate mofetil was given in addition, to those with hypo-hemoglobin (< 90 g/L), subcutaneous injection of erythropoietin was administered. Decoction of Qingre Huoxue recipe (QHR), consisted of oldenlandia herb 30 g, honey-suckle stem 30 g, violet herb 30 g, red peony root 15 g, rehmannia root 15 g, solomonseal rhizome 15 g, asiabell root 30 g, red sage root 30 g, prepared rhubarb 12 g and giant-hyssop herb 12 g, were additionally given one dose per day to patients in the treated group. The renal function, improvement of anemia and immunosuppressive agents needed in patients were observed after 3 months treatment. RESULTS: After treatment, renal function was improved in both groups, but the effect in the treated group was better than that in the control group (P < 0.05). Anemia was partially alleviated in the two groups with no significant difference. The dosage of glucocorticoids used in the treated group was obviously lesser than that used in the control group (P < 0.01). CONCLUSION: Integrative Chinese and western medicine could treat crescentic nephritis to obtain good effect, and reduce the quantity of glucocorticoid necessity for treatment.

Adult↗
PubMed2003

[Advance in the study on liquid fermentation for medicinal fungi].

The fermentation technology of medicinal fungi has been used widely. Improving the condition during the fermentation, getting more product, raising the quality of the product and cutting down the cost can minimize the ratio of input to outcome. People are working hard to achieve the aim. By the alteration of medium and culture condition on Ganoderma lucidum, Grifola frondosa and so on, different fermented products are got, especially secondary metabolires are remarkably different. Ultraviolet is used in selecting high quality Grifola frondosa (Gr 9801), Ganoderma lucidum strain. New high quality strain are selected. With the development of medicinal fungi fermentation, new analysis methods, such as HPCE are developed. The technology can be produced in mass in industry. It has a bright future for its virtues.

Agaricales↗
PubMed2002

Analysis of RNA flexibility by scanning force spectroscopy.

Scanning force spectroscopy was used to measure the mechanical properties of double stranded RNA molecules in comparison with DNA. We find that, similar to the B-S transition in DNA, RNA molecules are stretched from the assumed A' conformation to a stretched conformation by applying a defined force (plateau force). The force depends on the G + C content of the RNA and is distinct from that required for the B-S transition of a homologous DNA molecule. After the conformational change, DNA can be further extended by a factor of 0.7 +/- 0.2 (S-factor) before melting occurs and the binding of the molecule to the cantilever is finally disrupted. For RNA, the S-factor was higher (1.0 +/- 0.2) and more variable. Experiments to measure secondary structures in single stranded RNA yielded a large number of different force-distance curves, suggesting disruption and stretching of various secondary structures. Oriented attachment of the molecules to the substrate, a defined pick-up point and an increased resolution of the instrument could provide the means to analyse RNA secondary structures by scanning force spectroscopy.

Base Composition↗