Biomedical subjects

Dongsheng Zhang

Publications and source records attributed to Dongsheng Zhang.

23 records · Page 2Linked to original sources

PubMed2002

Identification of chronic cocaine-induced gene expression through dopamine d1 receptors by using cDNA microarrays.

A major goal of drug abuse research is to understand the molecular mechanisms underlying the behavioral changes caused by repeated exposure to cocaine. Enduring behavioral changes, such as behavioral sensitization, can be induced in rodents by repeated cocaine administration. The neurobiological mechanisms underlying such behavioral changes are associated with the brain mesocorticolimbic dopamine (DA) pathway. Moreover, the DA D1 receptors are involved in mediating the long-term behavioral effects of cocaine. The long-lasting behavioral effects of repeated cocaine exposure are highly likely to be associated with underlying changes in gene expression. To examine this possibility, we have started to combine the use of D1 receptor mutant mice with cDNA microarrays to identify gene expression changes mediated through the D1 receptors induced by repeated cocaine administration. Our initial experiments focused on a target of the mesocorticolimbic DA pathway, the nucleus accumbens (NAc), which is the primary neural substrate for mediating the long-term effects of cocaine. We found that multiple genes are differentially expressed in wild-type and D1 receptor mutant mice after chronic cocaine treatment. Further studies are in progress to determine the physiological significance of the differential expression of these genes in chronic cocaine-induced behaviors.

Animals↗

PubMed2002

A study of the ultrastructure and gene location of hereditary gingival fibromatosis.

OBJECTIVE: To ascertain histology changes of hereditary gingival fibromatosis (HGF) and the location of HGF gene. METHODS: A pedigree analyses of HGF; and the ultrastructure of gingival overgrowth tissue was observed with electron microscopy. The overgrowth of the HGF gene was defined with microsatellite markers. RESULTS: The connective tissue of HGF consisted of coarse collagen bundles and several kinds of cells arranged abnormally, such as: epithelial cells, smooth muscle cells and so on; the HGF locus had been mapped to chromosome 5q13-q22. CONCLUSIONS: The gingival pathologic changes resemble "hamartoma"; the findings has implications for identification of the underlying genetic basis of HGF.

Child↗

PubMed2000

[Effect of Arsenic Trioxide on Myelomonocytic Progenitor Cells in Patients with Myelodysplastic Syndrome in Vitro]

The Effect of arsenic trioxide (As(2)O(3)) on myelomonocytic progenitor cells of patients with myelodysplastic syndrome was studied. Bone marrow CFU-GM was assayed in the agar semi-solid culture, and the bone marrow cells were incubated in liquid culture and the expressions of CD33, CD15 and bcl-2 on the marrow cells were detected by APAAP method in 24 patients. The suppressive effects of As(2)O(3) to CFU-GM were increased with the rise of As(2)O(3) concentrations. The suppression of As(2)O(3) (0.388 micro mol/L) to cluster formation was stronger than to colony formation, the suppressive rates were 70.78% vs 34.05% in low-risk group, and 86.76% vs 65.86% in high-risk group (P < 0.01), respectively. 0.194 micro mol/L of As(2)O(3) decreased clusters and increased colonies in low-risk group, but decreased clusters and did not change colonies in high-risk group. High concentration (1.94 micro mol/L) of As(2)O(3) downregulated the expression rate of CD33 and CD15 in both groups, and low concentration (0.194 micro mol/L) downregulated the expression rate of CD33 and upregulated the expression rate of CD15 in low-risk group, but decreased expression of CD33 and did not alter CD15 in high-risk group. At the same time, the high concentration of As(2)O(3) downregulated expression of bcl-2 and resulted in karyopyknosis and cytoplasm condensation; low concentration generated similar effect on expression of bcl-2 and cell morphology in high-risk group, but did not affect in low-risk. It is concluded that As(2)O(3) suppressed myelopoiesis and impelled myelomonocytic cells to apoptosis, low concentration of As(2)O(3) induced the proliferation and differentiation of myelomonocytic cells in low-risk group, however, suppressed the growth of myelomonocytic cells and accelerated the cells apoptosis in high-risk group.

Journal Article↗

PubMedDate not supplied

Phase 2 study of the g209-2M melanoma peptide vaccine and low-dose interleukin-2 in advanced melanoma: Cancer and Leukemia Group B 509901.

High-dose interleukin-2 (IL-2) is the only approved immunologic therapy for advanced melanoma, but response rates are low and significant toxicities limit treatment to otherwise healthy patients. g209-2M is a nanopeptide engineered to mimic an epitope of the gp100 melanocyte differentiation protein that is recognized in a human leukocyte antigen (HLA)-restricted manner by melanoma tumor-infiltrating lymphocytes in some patients. Previous reports indicated that administration of the g209-2M peptide could induce g209-reactive circulating T cells in patients with melanoma and that the combination of g209-2M and high-dose IL-2 might be a more active treatment than high-dose IL-2 alone. Low-dose IL-2 is not active but has significant biologic effects, and because of a different toxicity profile, it can be offered to most patients. The primary objective of this cooperative group phase 2 study was to determine the activity of the combination of g209-2M and low-dose IL-2 in advanced melanoma. Twenty-six HLA appropriate patients with advanced melanoma received subcutaneous g209-2M peptide once every 3 weeks and subcutaneous IL-2 (5 million IU/m) daily for 5 days during the first and second weeks. Patients were monitored for tumor response, toxicity, and induction of g209-reactive circulating T cells. There were no objective responses. There were no toxic deaths and no grade 4 toxicities. More than half of the patients experienced some grade 2 toxicity and one quarter experienced grade 3 toxicity. There was no convincing evidence by enzyme-linked immunospot or tetramer analysis of induction of g209-reactive circulating T cells. The combination of g209-2M and low-dose IL-2 is safe and tolerable but inactive against advanced melanoma. Absence of evidence of immunization raises concerns for peptide-based immunization strategies with concurrent IL-2.

Adult↗

PubMedDate not supplied

Applications of digital image correlation to biological tissues.

Optical methods are becoming commonplace in investigations of the physical and mechanical behavior of biological tissues. Digital image correlation (DIC) is a versatile optical method that shows tremendous promise for applications involving biological tissues and biomaterials. We present the fundamentals of DIC with an emphasis on the application to biological materials. An approach for surface preparation is described that facilitates its application to hydrated substrates. Three examples are presented that highlight the use of DIC for biomedical research. The first example describes the use of DIC to study the mechanical behavior of arterial tissues up to 40% elongation. The second example describes an evaluation of the mechanical properties of bovine hoof horn in the dehydrated and fully hydrated states. Uniaxial tension experiments are performed to determine the elastic modulus (E) and Poisson's ratio (nu) of both the arterial and dermal tissues. Spatial variations in the mechanical properties are evident from the full-field characterization of both tissues. Finally, an application of DIC to study the evolution of loosening in cemented total hip replacements is described. The noncontact analysis enables measurement of the relative displacement between the bone/bone cement and bone cement/prosthesis interfaces. Based on the elementary optical arrangement, the simple surface preparation, and the ability to acquire displacement/strain measurements over a large range of deformation, DIC should serve as a valuable tool for biomedical research. Further developments will enable the use of DIC for in vivo applications.

Algorithms↗