Biomedical subjects

Yanfeng Zhong

Publications and source records attributed to Yanfeng Zhong.

5 recordsLinked to original sources

PubMed2005

Multiple organ infection and the pathogenesis of SARS.

After >8,000 infections and >700 deaths worldwide, the pathogenesis of the new infectious disease, severe acute respiratory syndrome (SARS), remains poorly understood. We investigated 18 autopsies of patients who had suspected SARS; 8 cases were confirmed as SARS. We evaluated white blood cells from 22 confirmed SARS patients at various stages of the disease. T lymphocyte counts in 65 confirmed and 35 misdiagnosed SARS cases also were analyzed retrospectively. SARS viral particles and genomic sequence were detected in a large number of circulating lymphocytes, monocytes, and lymphoid tissues, as well as in the epithelial cells of the respiratory tract, the mucosa of the intestine, the epithelium of the renal distal tubules, the neurons of the brain, and macrophages in different organs. SARS virus seemed to be capable of infecting multiple cell types in several organs; immune cells and pulmonary epithelium were identified as the main sites of injury. A comprehensive theory of pathogenesis is proposed for SARS with immune and lung damage as key features.

Adult↗

PubMed2005

Severe acute respiratory syndrome associated coronavirus is detected in intestinal tissues of fatal cases.

OBJECTIVES: A significant percentage of confirmed severe acute respiratory syndrome (SARS) patients experienced gastrointestinal symptoms, and the viral sequence was detectable in the stool of most patients. At present, the knowledge of the pathology of the digestive system in SARS patients is limited. Because a resurgence of the SARS epidemic is constantly possible, there is an urgent need to understand the involvement of the digestive system in this new disease. METHODS: We performed seven SARS autopsies in which samples of alimentary tract and digestive glands were examined with routine pathology, electron microscopy (EM), in situ hybridization (ISH), immunohistochemistry, and real-time polymerase chain reaction (PCR). RESULTS: The main histopathological finding was atrophy of the mucosal lymphoid tissue. A few mucosal epithelial cells and lymphocytes in the intestine were positively stained for coronavirus with ISH. SARS-coronavirus (CoV)-like particles were found in the mucosal epithelial cells under EM and mild focal inflammation was detected in the alimentary tract. One patient who experienced severe diarrhea had pseudomembranous enteritis of the ileum. Fatty degeneration and central lobular necrosis were observed in the liver. No evidence of direct viral infection was found in the esophagus, the stomach, the salivary gland, the liver, or the pancreas. CONCLUSIONS: In addition to the lungs, the gastrointestinal tract is another target of SARS-CoV infection, as the intestinal epithelial cells and mucosal lymphoid tissue are infected. The findings provide possible explanations for the gastrointestinal symptoms and the presence of virus in the stool of SARS patients.

Adult↗

PubMed2003

[Integrin alpha6 beta4 and experimental allergic neuritis].

OBJECTIVE: To explore the relationship between integrins alpha6,beta4 and the process of the injury and repair of the myelin, their expressions in experimental allergic neuritis were analyzed. METHODS: Experimental allergic neuritis (EAN) models were induced in Lewis rats. The expressions of integrins alpha6 and beta 4 and their receptor laminin, both in the acute phase and recovery phase of EANs, were analyzed by in situ hybridization and immunohistochemistry. RESULTS: The expression of beta4 decreased in the acute phase P<0.05 and showed no significant changes in the recovery phase(P=0.6840). There were no significant changes of the expression of alpha6 and laminin both in the acute phase and recovery phase of EANs by immunohistochemistry (alpha6 P=0.0751;laminin P=0.2047). The similar results were obtained by in situ hybridization (beta4 in acute phase P<0.05;beta4 in recovery phase P=0.823;alpha6 P= 0.81). CONCLUSION: The expressions of integrins of Schwann cells were affected by inflammation injury, and their patterns of expression were similar to those of integrins alpha6, beta1 and beta4 during embryogenesis. It is inferred that integrin beta4 and the reformation of myelin have a more imitate relationship. The expression changes of alpha6 and beta4 correlate with the injury and repair of myelin during EAN.

Animals↗

PubMed2003

[Effects of different pH values of fixatives and antigen retrieval buffers on immunohistochemical staining].

OBJECTIVE: To evaluate the influence of pH values of fixatives and antigen retrieval buffers on immunostains. METHODS: Samples of normal skin, gastric mucosa, uteri leiomyoma and breast carcinoma were fixed in buffered formalin with different pH values, namely 3.0, 5.0, 7.0, 8.0 and 10.0 to detect EMA, SMA, ER and CK (AE1/AE3) expression. Evinision two-step method was employed. Antigen retrieval was achieved by microwave using sodium citrate solution with pH 6.0, 7.0, 8.0 or pH 8.0 EDTA solution respectively. RESULTS: The number and intensity of positive cells varied due to different conditions. The change of positive cell's number is important for CK (AE1/AE3) expression, and the change of positive intensity is important for SMA and EMA expression. CONCLUSIONS: (1) The best results could be obtained by the use of 10% neutral or alkalescent buffered formalin. (2) Antigen retrieval effect is better in the solution of pH 7.0, 8.0 than in that of pH 6.0. EDTA(pH 8.0) appears better for skin. The best effect of Estrogen Receptor needs pH 8.0 sodium citrate solution. (3) The background could be easily induced by the fixative over pH 8.0. Antigen retrieval solution over pH 8.0 could result in detachment.

Buffers↗

PubMed2003

[Continual and quantitative analysis of cellular apoptosis by electron and fluorescence microscope].

OBJECTIVE: To evaluate the usage of fluorescent microscope in analyzing cellular apoptosis. METHODS: VP16 (the inhibitor of Top-II) and Azard Sodium(NaN3, the chemical toxic agent) were used to induce cellular apoptosis and necrosis respectively. The cellular changes were analyzed continually and quantitatively by transmission electromicroscope and fluorescent microscope stained by Hoechst 33258. RESULTS: Under the observation of fluorescent microscope and electromicroscope, HL60 cells showed pyknosis, chromatin aggregation and karyorrhexis (the features of apoptosis) in the induction of VP16; whereas the cells in the induction of NaN3 presented necrotic changes of karyolysis and chromatin diffusion. This indicated that there were different features in cellular apoptosis and necrosis under fluorescent microscope. In a time course observation of fluorescent microscope, the pyknosis began at 4 h after induction and peaked at 8 h, whereas karyorrheix reached 80% at 24 h, suggesting that the pyknosis preceded the karyorrheix. CONCLUSION: The fluorescent microscopic observation is a technique in continual and quantitative analysis of apoptosis, which may be used to distinguish the cellular apoptosis and necrosis.

Apoptosis↗