Biomedical subjects

Deng Pan

Publications and source records attributed to Deng Pan.

11 recordsLinked to original sources

PubMed2006

Method of x-ray anomalous diffraction for lipid structures.

The structures of the unit cells of lipid phases that exhibit long-range crystalline order but short-range liquid-like disorder are of biological interests. In particular, the recently discovered rhombohedral phase has a unit cell containing either the structure of a membrane fusion intermediate state or that of a peptide-induced transmembrane pore, depending on the lipid composition and participating peptides. Diffraction from such systems generally presents a difficult phase problem. The existing methods of phase determination all have their limitations. Therefore it is of general interest to develop a new phasing method. The method of multi-wavelength anomalous dispersion is routinely used in protein crystallography, but the same method is difficult for lipid systems for the practical reason that the commonly used lipid samples for diffraction do not have a well-defined thickness. Here we describe a practical approach to use the multi-wavelength anomalous dispersion method for lipid structures. The procedure is demonstrated with the lamellar phase of a brominated lipid. The method is general to all phases as long as anomalous diffraction is applicable.

Bromine↗

PubMed2006

Chain packing in the inverted hexagonal phase of phospholipids: a study by X-ray anomalous diffraction on bromine-labeled chains.

Although lipid phases are routinely studied by X-ray diffraction, construction of their unit cell structures from the diffraction data is difficult except for the lamellar phases. This is due to the well-known phase problem of X-ray diffraction. Here we successfully applied the multiwavelength anomalous dispersion (MAD) method to solve the phase problem for an inverted hexagonal phase of a phospholipid with brominated chains. Although the principle of the MAD method for all systems is the same, we found that for lipid structures it is necessary to use a procedure of analysis significantly different from that used for protein crystals. The inverted hexagonal phase has been used to study the chain packing in a hydrophobic interstice where three monolayers meet. Hydrophobic interstices are of great interest, because they occur in the intermediate states of membrane fusion. It is generally believed that chain packing in such a region is energy costly. Consequently, it has been speculated that the inverted lipid tube is likely to deviate from a circular shape, and the chain density distribution might be nonuniform. The bromine distribution obtained from the MAD analysis provides the information for the chain packing in the hexagonal unit cell. The intensity of the bromine distribution is undulated around the unit cell. The analysis shows that the lipid chains pack the hexagonal unit cell at constant volume per chain, with no detectable effect from a high-energy interstitial region.

Cholesterol↗

PubMed2006

[Population genetics of Rhinopithecus bieti: a study of the mitochondrial control region].

Yunnan snub-nose monkey (Rhinopithecus bieti) is a famous endangered primate in China. So far, however, studies on its population genetics based on DNA sequences are not available. In this paper, the whole mitochondria control region of the samples from Weixi, Yunan Province as well as the whole cytochrome b gene in some individuals were sequenced. A deep divergence was observed within the Weixi population, which was confirmed after excluding the possibility of it being a nuclear pseudogene. Nonetheless, if the effects of population structure and migration are considered, the true level of polymorphism of the Weixi population may be not as high as observed.

Animals↗

PubMed2005

The integral inner nuclear membrane protein MAN1 physically interacts with the R-Smad proteins to repress signaling by the transforming growth factor-{beta} superfamily of cytokines.

Smad proteins are critical intracellular mediators of the transforming growth factor-beta, bone morphogenic proteins (BMPs), and activin signaling. Upon ligand binding, the receptor-associated R-Smads are phosphorylated by the active type I receptor serine/threonine kinases. The phosphorylated R-Smads then form heteromeric complexes with Smad4, translocate into the nucleus, and interact with various transcription factors to regulate the expression of downstream genes. Interaction of Smad proteins with cellular partners in the cytoplasm and nucleus is a critical mechanism by which the activities and expression of the Smad proteins are modulated. Here we report a novel step of regulation of the R-Smad function at the inner nuclear membrane through a physical interaction between the integral inner nuclear membrane protein MAN1 and R-Smads. MAN1, through the RNA recognition motif, associates with R-Smads but not Smad4 at the inner nuclear membrane in a ligand-independent manner. Overexpression of MAN1 results in inhibition of R-Smad phosphorylation, heterodimerization with Smad4 and nuclear translocation, and repression of transcriptional activation of the TGFbeta, BMP2, and activin-responsive promoters. This repression of TGFbeta, BMP2, and activin signaling is dependent on the MAN1-Smad interaction because a point mutation that disrupts this interaction abolishes the transcriptional repression by MAN1. Thus, MAN1 represents a new class of R-Smad regulators and defines a previously unrecognized regulatory step at the nuclear periphery.

Bone Morphogenetic Protein 2↗

PubMed2005

Differential gene expression profile in hepatopancreas of WSSV-resistant shrimp (Penaeus japonicus) by suppression subtractive hybridization.

In order to find the immune-relevant factors responsible for the virus resistance in the WSSV-resistant shrimp, a suppression subtractive hybridization method was employed to identify differentially expressed genes and their expression profile in the hepatopancreas of the virus-resistant penaeid shrimp. Thirty five genes were identified from more than 400 clones, of which eight are found for the first time in penaeid shrimp. betaGBP is the most abundant gene in our subtractive library except hemocyanin. Lectin, ferritin, oxygenase and chitinase of the virus-resistant shrimp all showed up-regulation in expression compared with those of normal shrimp. In addition, Ranbp, Rho and Rab were found in the subtractive library. This is the first evidence indicating that small GTPases are involved in the signal transduction in shrimp defense response. Furthermore, a number of genes encoding apoptotic-related proteins and antioxidant enzymes were expressed at a higher level in the virus-resistant shrimp. In short, the high expression of immuno-related genes in response to the virus infection and the involvement of small GTPases in the antiviral response provide a new insight for further study in the crustacean innate immunity.

Amino Acid Sequence↗

PubMed2005

Cross-cultural adaptation and validation of the Brazilian Portuguese version of the short musculoskeletal function assessment questionnaire: the SMFA-BR.

BACKGROUND: This study was designed to translate, culturally adapt, and validate a Brazilian Portuguese version of the Short Musculoskeletal Function Assessment Questionnaire (SMFA-BR). METHODS: The SMFA was translated from English into Brazilian Portuguese. Translations were synthesized, translated back into English, and then submitted to a committee of clinical, psychometric, and language experts. The questionnaire was then administered to 220 trauma patients at a midsize hospital in southern Brazil. Test-retest reliability was examined at one and seven days. Scale reliability and validity were assessed, and factor structure was analyzed. RESULTS: Patients with only one region of dysfunction reported less dysfunction than did patients with two or three regions of dysfunction. Both the SMFA-BR dysfunction and the SMFA-BR bother scores had significant correlations with all Brazilian Short Form-36 (SF-36) subscales except for bodily pain. Test-retest reliabilities, as determined by intraclass correlation analyses, were 0.99 (95% confidence interval, 0.97, 1.00) at one day (n = 10) and 0.99 (95% confidence interval, 0.96, 1.00) at seven days (n = 17) for the dysfunction index and 0.99 (95% confidence interval, 0.98, 1.00) at one day (n = 10) and 0.97 (95% confidence interval, 0.97, 1.00) at seven days (n = 17) for the bother index. Cronbach alpha reliabilities were 0.95 (95% confidence interval, 0.93, 0.97) and 0.91 (95% confidence interval, 0.89, 0.94) for the dysfunction and bother indices, respectively. Minimal ceiling and floor effects were observed for the bother subscale only. Exploratory factor analysis yielded a three-factor structure: upper-extremity dysfunction, lower-extremity dysfunction, and bother. CONCLUSIONS: A reliable and valid Brazilian Portuguese version of the SMFA was developed. It will facilitate the examination of functional performance within a large patient population as well as allow cross-cultural comparisons.

Adolescent↗

PubMed2005

The impact of diabetes on patient outcomes after ankle fracture.

BACKGROUND: Ankle fracture is one of the most common injuries treated by orthopaedic surgeons, and the presence of diabetes complicates treatment and recovery from this injury. Although a higher prevalence of adverse postoperative events has been found in small series of diabetic patients with an ankle fracture, we are not aware of any large national series with specific documentation of the outcomes following ankle fracture in patients with diabetes. METHODS: We analyzed data from the Nationwide Inpatient Sample database for the years 1988 through 2000. Information regarding the hospitalizations of 160,598 adult patients with an ankle fracture who underwent subsequent surgical procedures was extracted from the database. Multiple linear and logistic regression models were used to ascertain whether patients with diabetes mellitus were more likely than patients without diabetes mellitus to die while in the hospital, to have in-hospital postoperative complications, to stay longer in the hospital, to have a higher incidence of non-routine discharge, and to have a higher total cost associated with the hospital stay. RESULTS: Significant increases in in-hospital mortality, the rate of in-hospital postoperative complications, the length of hospital stay, the rate of non-routine discharge, and the total charges were found in the diabetic patient group (p < 0.001). Specifically, we found that diabetic patients across all levels of fracture severity (closed unimalleolar, closed bimalleolar or trimalleolar, and dislocated or open fractures) stayed in the hospital for about one additional day (mean, 4.7 compared with 3.6 days) and incurred more than dollar 2000 in increased charges (mean, dollar 12,898 compared with dollar 10,794). CONCLUSIONS: This nationally representative study of inpatients in the United States provides evidence that diabetic patients with an operatively treated ankle fracture are likely to have worse results than non-diabetic patients with regard to postoperative complications, mortality, rate of non-routine discharge, length of hospital stay, and total hospital charges.

Ankle Injuries↗

PubMed2005

[Immunohistochemical evidence for HIV-1 infection in the liver of HIV-infected patients].

OBJECTIVE: To detect p24 antigen of human immunodeficiency virus (HIV)-1 in the liver biopsy specimens of patients with HIV infection. METHODS: Liver biopsy samples from 14 patients with HIV/AIDS (11 man, 3 women; age range 27-52 years; infection time range 8-13 years) were examined by immunohistochemistry prospectively. RESULTS: Intracellular expression of HIV-1 p24 antigen was detected in Kupffer cells, endothelial cells and hepatocytes. There were more HIV-positive liver cells in the patients with severer liver damage than those with milder liver damage (t=2.5189, P=0.0270). CONCLUSION: These findings indicate that HIV-1 could replicate in the liver of HIV-infected patients and might be related to the liver cells apoptosis.

Adult↗

PubMed2004

Identification of the thymidylate synthase within the genome of white spot syndrome virus.

Thymidylate synthase (TS) (EC 2.1.1.45) is essential for the de novo synthesis of dTMP in prokaryotic and eukaryotic organisms. Within the white spot syndrome virus (WSSV) genome, an open reading frame (WSV067) that encodes a 289 amino acid polypeptide showed significant homology to all known TSs from species including mammals, plants, fungi, protozoa, bacteria and DNA viruses. In this study, WSV067 was expressed in Escherichia coli, and the purified recombinant protein showed TS activity in dUMP-folate-binding assays using ultraviolet difference spectroscopy. RT-PCR and Western blot analyses showed that WSV067 was a genuine and early gene. Phylogenetic analysis revealed that WSSV-TS was more closely related to the TSs of eukaryotes than to those from prokaryotes.

Amino Acid Sequence↗

PubMed2003

[Clinical pathology and pathogenesis of severe acute respiratory syndrome].

BACKGROUND: To explore the pathological features and pathogenesis of severe acute respiratory syndrome (SARS) to provide evidence for the clinical treatment and prevention of SARS. METHODS: Pathological features of 2 cases of full autopsy and 4 cases of needle biopsy tissue samples from the patients who died from SARS were studied by light and electron microscopy. The distribution and quantity of lymphocyte subpopulations in the lungs and immune organs from SARS patients were analyzed by immunohistochemistry. The location and semi-quantitative analysis of SARS coronavirus in the tissue specimens were studied by electron microscopy, in situ hybridization and immunohistochemistry. RESULTS: In total of 6 cases, diffuse alveolar damage and alveolar cell proliferation were common. The major pathological changes of 2 autopsy cases of SARS in lung tissues were acute pulmonary interstitial and alveolar exudative inflammation, and 2 autopsy and one biopsy lung tissues showed alveolar hyaline membrane formation. Terminal bronchiolar and alveolar desquamation of lung tissues in one autopsy and 2 biopsy cases were noted. Among 6 cases, 2 biopsy cases presented early pulmonary fibrosis and alveolar organization. Meanwhile, the immune organs, including lymph nodes and spleens from 2 autopsy cases of SARS whose disease courses were less than 12 days showed extensive hemorrhagic necrosis, reactive macrophage/histocyte proliferation, with relative depression of mononuclear and granulocytic clones in the bone marrows. However, spleen and bone marrow biopsy tissue samples from 4 dead SARS cases whose clinical course lasted from 21 to 40 days presented repairing changes. SARS coronaviruses were mainly identified in type I and II alveolar epithelia, macrophages, and endothelia; meanwhile, some renal tubular epithelial cells, cardiomyocytes, mucosal and crypt epithelial cells of gastrointestinal tracts, parenchymal cells in adrenal glands, lymphocytes, testicular epithelial cells and Leydig's cells were also detected by electron microscopy combined with in situ hybridization. The semi-quantitative analysis of lymphocyte subpopulations revealed that the proportion of CD8+ T lymphocytes were about 80% of the total infiltrative inflammatory cells in the pulmonary interstitium, with a few CD4+ lymphocytes CD3+, CD4+, CD8+ or CD20+ lymphocyte subpopulations were obviously decreased and there was imbalance in number and proportion, while CD57+, CD68+, S-100+ and HLA-DR+ cells were relatively increased in lymph nodes and spleens. CONCLUSIONS: Histologically, the pulmonary changes could be divided into acute inflammatory exudative, terminal bronchiolar and alveolar desquamative and proliferative repair stages or types during the pathological process of SARS. SARS coronavirus was found in multi-target cells in vivo, which means that SARS coronavirus might cause multi-organ damages which were predominant in lungs. There were varying degrees of decrease and imbalance in number and proportion of lymphocyte subpopulations in the immune organs of the patients with SARS. However, these changes may be reversible. It was found that cellular immune responses were predominant in the lungs of SARS cases, which might play an important role in getting rid of coronaviruses in infected cells and inducing immune mediated injury.

Aged↗

PubMedDate not supplied

National trends in health care utilization and racial and socioeconomic disparities in pediatric pyogenic arthritis.

PURPOSE: To determine national trends and putative racial and socioeconomic disparities in health care utilization in pediatric patients with pyogenic arthritis over a 13-year period. STUDY DESIGN: We assessed trends in length of hospital stay, hospital disposition, and inflation-adjusted charges for pediatric patients hospitalized with pyogenic arthritis based on 13 consecutive years (1988-2000) of the Nationwide Inpatient Sample. Patients with an International Classification of Diseases, Ninth Revision code of pyogenic arthritis were selected for this study. Trends in health care utilization were analyzed, stratified by age, prematurity, joint location, socioeconomic status, and race. RESULTS: The median length of stay (LOS) decreased from 10 to 5 days in 1988 and 2000, respectively (P < 0.05). Whites had a shorter mean LOS (7.8 days) than nonwhites (10.7 days; P < 0.05). For both whites and nonwhites, LOS decreased significantly (P < 0.05), but the difference between the 2 groups remained constant. For patients with a higher socioeconomic status, LOS was shorter (P'< 0.05). The percentage of patients discharged to home'health care increased from 3.8% in 1988 to 18.9% in 2000 (P'< 0.05), but the increase was much greater for whites than nonwhites (P < 0.05). Inflation adjusted total charges increased over time, from a median total charge of 10,098 dollars in 1988 to a median total charge of 11,155 dollars in 2000 (P < 0.05). CONCLUSIONS: There was a trend toward decreased health care utilization, but no decrease in charges for pediatric pyogenic arthritis from 1988 to 2000. Racial disparities still exist, with little improvement over time.

Adolescent↗