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Biomedical subjects

S Su

Publications and source records attributed to S Su.

At least 19 recordsLinked to original sources
PubMed2005

Use of the z-transform to investigate nanopulse penetration of biological matter.

Short duration, fast rise time electromagnetic ultra-wideband (UWB) pulses ("nanopulses") are generated by numerous electronic devices. Many new technologies involving nanopulses are under development and expected to become widely available soon. Study of nanopulse bioeffects therefore is needed to ensure human safety and to probe the useful range of nanopulses in possible biomedical and biotechnological applications. In this article, we present a new approximation of the Cole-Cole expression for the frequency dependence of the dielectric properties of tissues. The approximation is based on a z-transformation of the electric displacement and a second-order Taylor approximation of the Cole-Cole expression. The approach has been applied to investigating the penetration of nanopulses into biological matter as a function of the dielectric properties of tissue and pulse width. Solutions to Maxwell's equations are calculated using the finite difference time domain method (FDTD).

Algorithms↗
PubMed2004

Regional metabolism in primary torsion dystonia: effects of penetrance and genotype.

BACKGROUND: The authors have previously used [18F]fluorodeoxyglucose (FDG) PET to identify a reproducible pattern of regional glucose metabolism that was expressed in both manifesting and nonmanifesting carriers of the DYT1 primary dystonia mutation. OBJECTIVE: To identify specific regions that discriminated subjects according to clinical penetrance and genotype. METHODS: FDG PET was used to scan 12 nonmanifesting and 11 manifesting DYT1 gene carriers, 6 nonmanifesting DYT6 gene carriers and 7 manifesting DYT6 gene carriers, as well as 11 control subjects. The data from all five groups were analyzed with statistical parametric mapping and analysis of variance with posthoc contrasts. RESULTS: A dissociation of metabolic changes was found related to phenotype and genotype. Manifesting gene carriers of both genotypes exhibited bilateral hypermetabolism in the presupplementary motor area (Brodmann area [BA] 6) and parietal association cortices (BA 40/7) compared with the respective nonmanifesting counterparts. By contrast, genotype-specific increases in metabolism were found in the putamen, anterior cingulate (BA 24/32), and cerebellar hemispheres of DYT1 carriers. Genotype-specific changes in DYT6 involved hypometabolism of the putamen and hypermetabolism in the temporal cortex (BA 21). CONCLUSIONS: Dystonia may be associated with abnormal movement preparation caused by defective sensorimotor integration. Whereas clinical manifestations are related to cortical dysfunction, metabolic abnormalities in subcortical structures may represent trait features that are specific for individual dystonia genotypes.

Adolescent↗
PubMed2001

Overexpression of HER-2/neu enhances the sensitivity of human bladder cancer cells to urinary isoflavones.

Soybean foods have been suggested to be practical chemopreventives for human urinary tract cancers. Recently, we demonstrated that the co-operative action of isoflavones results in an increased dose-dependent growth inhibition and apoptosis than any single isoflavone compound. This study aimed to examine the potential of HER-2/neu as a biological target for soy isoflavones. The sensitivity of the bladder cancer cell lines (n=7) to the isoflavones was inversely related to the amount of HER-2/neu expressed. By using HER-2/neu transfection experiments, all three stable transfectants showed a significant growth inhibition by the isoflavone mixture at concentrations attainable in normal adult urine. An increased inhibition of tyrosine phosphorylation of proteins immunoprecipitated by HER-2/Neu was observed in the neu-transfectants compared with controls. The results of this study suggest that HER-2/neu may be a practical biochemical target for urinary isoflavones in vivo.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Chiropractic and a new taxonomy of primary care activities.

OBJECTIVE: To specify the procedural and cognitive content of primary care and to discuss potential chiropractic primary care roles. DATA COLLECTION: Data were collected through use of two expert panels and a consensus process to create a list of primary care activities. The first panel was an interdisciplinary mix of physicians, mainly allopathic ones; most of the members of the second panel were chiropractors. Each panel rated primary care activities across a number of dimensions, such as importance for good health, frequency in a typical office-based practice, necessity for medical doctor involvement in the activity, competence of the majority of chiropractic physicians, and interest among chiropractors in performing the activity. RESULTS: There was no real difference between the panels in terms of taxonomy scope or importance of the activities for good health. Many of the activities are performed more frequently in a typical medical office than in a typical chiropractic office. With respect to a set of primary care activities that occur daily in medical offices, chiropractors are able to make diagnoses in 92% of the activities and to make therapeutic contributions in more than 50% of the activities. Medical doctor involvement was perceived as required more frequently by the chiropractic panel than by the interdisciplinary panel. Moreover, chiropractors' interests and self-assessments of competence showed some limits with regard to their assumption of total care for some frequently occurring primary care activities. CONCLUSIONS: The most important finding of this activity is the overriding sense of agreement between allopathic and chiropractic physicians in terms of the scope of primary care activities, suggesting that there is opportunity for chiropractors and medical doctors to work together on patient care and organizational strategy. However, the levels of self-assessed competence and interest on the part of chiropractors for many frequently occurring primary care activities reveal some important limits for assumption of total primary care.

Chiropractic↗
PubMed2001

Mass transport analysis: inhalation rfc methods framework for interspecies dosimetric adjustment.

In 1994, the U.S. Environmental Protection Agency introduced dosimetry modeling into the methods used to derive an inhalation reference concentration (RfC). The type of dosimetric adjustment factor (DAF) applied had to span the range of physicochemical characteristics of the gases listed on the Clean Air Act Amendments in 1991 as hazardous air pollutants (HAPs) and accommodate differences in available data with respect to their toxicokinetic properties. A framework was proposed that allowed for a hierarchy of dosimetry model structures, from optimal to rudimentary, and a category scheme that provided for limiting model structures based on physicochemical and toxicokinetic properties. These limiting cases were developed from restricting consideration to specific properties relying on an understanding of the generalized system based on mass transport theory. Physiochemical characteristics included the solubility and reactivity (e.g., propensity to dissociate, oxidize, or serve as a metabolic substrate) of the gas and were used as major determinants of absorption. Dosimetric adjustments were developed to evaluate portal of entry (POE) effects as well as remote (systemic) effects relevant to the toxicokinetic properties of the gas of interest. The gas categorization scheme consisted of defining three gas categories: (1) gases that are highly soluble and/or reactive, absorbing primarily in the extrathoracic airways; (2) gases that are moderately soluble and/or reactive, absorbing throughout the airways, as well as accumulating in the bloodstream; and (3) gases that have a low water solubility and are lipid soluble such that they are primarily absorbed in the pulmonary region and likely to act systemically. This article presents the framework and the mass transport theory behind the RfC method. Comparison to compartmental approaches and considerations for future development are also discussed.

Algorithms↗
PubMed2001

[Initiative report of the hydroxyapatite orbital implant drilling procedure].

OBJECTIVE: To evaluate the clinical effect of drilling procedure following the hydroxyapatite orbital implantation. METHODS: From February 1996 to April 2000, 146 consecutive patients who received hydroxyapatite orbital implant were drilled and inserted a motility peg 6 to 16 months after hydroxyapatite implantation. Among them, there were 97 males and 49 females, aged from 18 to 60 years old, of the 146 motility pegs, 36 were sleeved pegs and 110 were nonsleeved. Goldman visual field analyzer was applied to measure the degree of artificial eye's movement before and after drilling. RESULTS: Followed up for 1 to 40 months, no secondary infection occurred. The mobility of the prosthesis increased from (18.7 +/- 3.8) degrees preoperatively to (42.3 +/- 3.7) degrees postoperatively. CONCLUSION: The delayed drilling procedure and motility peg insertion improve the range of movement and the sensitivity of the artificial eye with a low rate of complications.

Adolescent↗
PubMed2000

Crystal structures of the chromosomal proteins Sso7d/Sac7d bound to DNA containing T-G mismatched base-pairs.

Sso7d and Sac7d are two small chromatin proteins from the hyperthermophilic archaeabacterium Sulfolobus solfataricus and Sulfolobus acidocaldarius, respectively. The crystal structures of Sso7d-GTGATCGC, Sac7d-GTGATCGC and Sac7d-GTGATCAC have been determined and refined at 1.45 A, 2.2 A and 2.2 A, respectively, to investigate the DNA binding property of Sso7d/Sac7d in the presence of a T-G mismatch base-pair. Detailed structural analysis revealed that the intercalation site includes the T-G mismatch base-pair and Sso7d/Sac7d bind to that mismatch base-pair in a manner similar to regular DNA. In the Sso7d-GTGATCGC complex, a new inter-strand hydrogen bond between T2O4 and C14N4 is formed and well-order bridging water molecules are found. The results suggest that the less stable DNA stacking site involving a T-G mismatch may be a preferred site for protein side-chain intercalation.

Amino Acid Sequence↗
PubMed2000

N36, a synthetic N-terminal heptad repeat domain of the HIV-1 envelope protein gp41, is an activator of human phagocytes.

Human immunodeficiency virus type 1 (HIV-1) envelope protein gp41 mediates viral fusion with human host cells. In this study we show that N36, a synthetic peptide derived from the N-terminus of gp41, induced directional migration and calcium mobilization in human monocytes and neutrophils. The activity of N36 on phagocytes was pertussis toxin sensitive, suggesting involvement of a Gi-coupled seven-transmembrane receptor(s). Since high concentrations of the bacterial chemotactic peptide fMet-Leu-Phe (fMLF) partially desensitized the calcium mobilizing activity of N36 in phagocytes, we postulated that N36 might use a low-affinity fMLF receptor. By using cells stably expressing fMLF receptor FPR or FPRL1, we demonstrate that N36 uses FPRL1 as a functional receptor. Our results suggest that HIV-1 gp41 may contain a fragment(s) that activates the innate host immune cells through FPRL1. Since the activation of FPRL1 in monocytes has been shown to heterologously desensitize chemokine receptors, the reduced phagocyte response to chemoattractants seen in AIDS patients may be attributed, at least in part, to heterologous desensitization.

Anti-HIV Agents↗
PubMed2000

[Molecular epidemiological study on HIV-1 infection in Shandong Province].

OBJECTIVE: The aim of this study was to understand the distribution of HIV-1 strain subtypes and their variation in Shandong Province and to analyze their source and predict their epidemic trend. METHODS: We collected the whole blood from 25 anti-HIV-1 antibody positive cases and separated the peripheral blood mononuclear cells. The provirus DNA was extracted and amplified by nested-PCR, after which the HIV-1 membrane protein gene (env) C2-V3 region was sequenced and its subtype was analyzed. RESULTS: Among 25 HIV-1 antibody positive cases, 24 HIV-1 env gene fragments were amplified and analyzed.5 subtypes of Group HIV-1 M were identified among these cases,that are subtypes A, B, B', C and E. 13 occupational blood donors were all classified as subtype B' (Thailand B'). A, B, C or E subtypes were discovered in 10 returned laborers working abroad and 1 female spouse of one laborer. CONCLUSIONS: The condition of HIV-1 subtype infection was complicated in Shandong Province. So, it is important to strengthen the surveillance and control of HIV-1 subtype strain infection in high risk populations especially the occupational blood donors and returned laborers working abroad to prevent its spread in Shandong Province.

Adult↗
PubMed2000

[The study of expression and distribution of PCNA in hypertrophic scar tissue].

OBJECTIVE: To analyze the expression and the distribution of proliferation cell nuclear antigen (PCNA) in hypertrophic scar for identifying its certain characteristics during the fibroblast proliferation. METHODS: Bioptic samples were taken form 12 cases of hypertrophic scar, 8 cases of matured scars and 20 cases of controlled normal skin. Each sample was immunohistochemically stained and examined with monoclonal antibody[PCNA(pc10)] technique. The level of PCNA expression was decided for evaluation of the fibroblast proliferation. RESULTS: The level of PCNA in the hypertrophic scar(45.4 +/- 12.3) was significantly higher than mature scar(17.4 +/- 6.2), also normal skin(13.5 +/- 4.1, P < 0.01). But, there was no significant deference between the matured scar and the normal skin. The PCNA intracellular particles may sometimes be bound in the keratinocytes and the fibroblasts of some connective tissue. CONCLUSION: The fibroblast proliferation in the hypertrophic scar has kept a high level. During the process of hypertrophic scar formation it may play an important role.

Adolescent↗
PubMed2000

[Analysis on the characteristic and trend of AIDS epidemics in Shandong].

OBJECTIVE: To analyse the data thru labs and field epidemiological investigation from 1987 to 1999, in order to find out the characteristics, sources of infections and its trend which would lead to the development of strategy, prevention and control of AIDS in Shandong. METHODS: Anti-HIV antibody was detected by ELISA and WB in the serum of high-risk groups. When Anti-HIV antibody was positive, personal and epidemiological history was investigated. The anticoagulated blood was repeatedly collected to verify the infected people. PBMCs were separated from the anticoagulated blood to collect previrus DNA. Gene sequence was then detected and subtype analysed by PCR using ABI company kit. RESULTS: Eight hundred five thousand eight hundred and one specimens were detected in the whole province from 1987 to 1999. 52 cases showed Anti-HIV antibody positive, with a rate of 0.06 per thousand. Of the 52 cases, 2 died. Sequence detection and subtype analysis of PBMC in 24 infected people showed that there were five HIV-1 subtypes M: A, B, B', C, E which were from 7 cities of the province. Blood and sexual transmission took the majority with proportions, 59.62% and 30.76% respectively. The subtypes from 13 blood donors were all B'. Among 10 labourers refurned from abroad and 1 spouse six cases were C, two were B, and another two were A and E subtypes respectively. Epidemiologic data showed that most of the infected people were mobile, making sexual transmission easy to occur. CONCLUSION: The moods of HIV/AIDS transmission in Shandong were mainly through blood and sexual contacts.

Acquired Immunodeficiency Syndrome↗
PubMed2000

[Changes of plasma nitric oxide and tumor necrosis factor-alpha in lung elastase injury induced inflammatory response of hamster].

OBJECTIVE: To investigate the role of the NO and TNF-alpha in lung elastase injury induced inflammatory response of hamster. METHODS: Lung elastase injury induced inflammatory hamster model was established. NOS activity in airway epithelial cells and lung monocytes/macrophage, as well as the serum content of NO and TNF-alpha were measured respectively. RESULTS: The results indicated that iNOS activity in epithelium and monocytes/macrophages were significantly enhanced. In the early period of inflammation the NO and TNF-alpha content in serum increased obviously and maintained in a high level (P < 0.001). CONCLUSIONS: This Study suggested that both NO and TNF-alpha are important mediators participating in the lung elastase injury-induced inflammatory response. Our data suggested NO might play a regulatory role in the release of TNF-alpha.

Animals↗
PubMed1999

Serum lysozyme activity can differentiate infection from rejection in organ transplant recipients.

BACKGROUND: The presentation of infection in immunocompromised patients can be subtle. Patients often undergo extensive testing and empiric treatment for rejection and infection while awaiting the results of the biopsy and culture results. Delay in diagnosis of either entity can result in a worse clinical outcome. Lysozyme activity has been found to be both a sensitive and a specific marker for infection in laboratory animals and trauma patients. Our goal was to determine whether lysozyme activity could serve as a reliable marker for infection in immunocompromised organ transplant recipients. METHODS: Transplant recipients from three clinical categories were enrolled in this study. Group 1 (n = 16) were patients hospitalized for sepsis (culture-positive), and Group 2 (n = 13) for biopsy-proven rejection. Group 3 (n = 51) were recipients who had routine blood sampling in the clinic. In Groups 1 and 2, blood was collected within 24 h of hospital admission and centrifuged, and serum samples were stored at 80 degrees C until processing. Lysozyme activity was assayed by turbidimetric measurement on a sample of a standard suspension (0.15 mg/ml) of Micrococcus lysodeikticus in buffer using a spectrophotometer to read the optical density at 450 nm. The lysozyme activity level was then determined by the measuring activity at 1 min subtracted from activity at 4 min. White blood cell count was determined by using a flow cytometer. Statistical comparisons between groups were made using paired Student's t test. RESULTS: Serum lysozyme was found to be significantly elevated in Group 1; the mean level of activity was 60.1 +/- 13 (P < 0.05) compared to the level of activity in Group 2, mean 41.1 +/- 11, and Group 3, mean 40.8 +/- 13. A level of 45 units of activity/ml of serum or above indicated infection and not rejection in the patients admitted to the hospital. CONCLUSIONS: These findings indicate that the lysozyme activity assay appears to be useful in differentiating infection from rejection in transplant recipients.

Adolescent↗
PubMed1999

Expression of the tissue inhibitor of metalloproteinases (TIMP) gene family in normal and osteoarthritic joints.

The pathophysiological and biological significance of tissue inhibitor of the metalloproteinases-3 (TIMP-3) gene compared to other TIMPs was investigated in osteoarthritic (OA) human and normal bovine joint tissues. Human OA synovial fibroblasts in culture constitutively expressed TIMP mRNAs. TIMP-3, TIMP-1 and gelatinase A mRNAs were elevated in most human OA synovia over controls, while TIMP-2 expression was similar. TIMP-3 and TIMP-1 mRNAs present in bovine cartilage were inducible by serum factors. Transforming growth factor beta (TGF-beta 1) induced TIMP-3 RNA and protein in human OA and normal bovine chondrocytes. TIMP mRNAs were low (TIMP-1) or undetectable in human fetal chondrocytes but were expressed at all other ages. Thus, the two main joint tissues, synovial membranes and cartilage, express TIMP genes. Due to their matrix protecting activities, the presence of multiple TIMPs may be beneficial for normal joints, while increased TIMP-3 and TIMP-1 expression in arthritic joints may be associated with pathological remodeling.

Aged↗
PubMed1999

Applications of knowledge discovery to molecular biology: identifying structural regularities in proteins.

In recent years, there has been an explosive amount of molecular biology information obtained and deposited in various databases. Identifying and interpreting interesting patterns from this massive amount of information has become an essential component in directing further molecular biology research. The goal of this research is to discover structural regularities in protein sequences by applying the Subdue discovery system to databases found in the Brookhaven Protein Data Bank. In this paper we report the results of applying Subdue to several classes of protein structures and discuss the potential significance of these results to the study of proteins.

Amino Acid Sequence↗
PubMed1999

Induction of stromelysin gene expression by tumor necrosis factor alpha is inhibited by dexamethasone, salicylate, and N-acetylcysteine in synovial fibroblasts.

Proinflammatory cytokines, altered connective tissue metabolism, and overexpression of matrix metalloproteinases (MMPs) such as stromelysin compared to tissue inhibitors of metalloproteinases (TIMPs) result in synovial inflammation and erosion of arthritic cartilage. Tumor necrosis factor alpha (TNF-alpha) is a major synovial inflammatory mediator responsible for inhibiting extracellular matrix (ECM) synthesis and stimulating degradation of cartilage ECM by activated MMPs in arthritic joints. To suppress these effects and to gain insight into the mechanism of TNF-alpha action, we identified the inhibitors of TNF-alpha stimulation of stromelysin gene expression. In bovine synovial fibroblasts, TNF-alpha did not affect a recently identified inhibitor, TIMP-3, but induced stromelysin mRNA expression in a dose- and time-dependent fashion (3- to 5-fold) which required de novo protein synthesis. Stimulation by TNF-alpha was potently inhibited (99-100%) by the synthetic glucocorticoid, dexamethasone. Sodium salicylate dose-dependently inhibited (100%) the TNF-alpha action. Indomethacin and ibuprofen were partially inhibitory. Free radical scavenger antioxidant, N-acetylcysteine (but not other antioxidants) also suppressed the TNF-alpha induction (36-100%) of stromelysin suggesting involvement of reactive oxygen species in the induction process. TNF-alpha induction of stromelysin gene expression can therefore be inhibited at the gene expression level by several pharmacological agents which are likely to function via arachidonic acid metabolites, free radical scavenging or interference with the activator protein 1, polyoma virus enhancer A-binding protein 3, and nuclear factor kappaB classes of transcription factors. Our results may help to elucidate the mechanism of TNF-alpha action and explain the beneficial role of these agents in the treatment of inflammatory diseases.

Acetylcysteine↗