Biomedical subjects

D Yang

Publications and source records attributed to D Yang.

At least 145 records · Page 8Linked to original sources

PubMed2000

Integrative physiology of splanchnic glutamine and ammonium metabolism.

The substrates for hepatic ureagenesis are equimolar amounts of ammonium and aspartate. The study design mimics conditions in which the liver receives more NH(+)(4) than aspartate precursors (very low-protein diet). Fasted dogs, fitted acutely with transhepatic catheters, were infused with a tracer amount of (15)NH(4)Cl. From arteriovenous differences, the major NH(+)(4) precursor for hepatic ureagenesis was via deamidation of glutamine in the portal drainage system (rather than in the liver), because there was a 1:1 stoichiometry between glutamine disappearance and NH(+)(4) appearance, and the amide (but not the amine) nitrogen of glutamine supplied the (15)N added to the portal venous NH(+)(4) pool. The liver extracted all this NH(+)(4) from glutamine deamidation plus an additional amount in a single pass, suggesting that there was an activator of hepatic ureagenesis. The other major source of nitrogen extracted by the liver was [(14)N]alanine. Because alanine was not produced in the portal venous system, we speculate that it was derived ultimately from proteins in peripheral tissues.

Acid-Base Equilibrium↗

PubMed2000

Quality measures for mental health care: results from a national inventory.

The National Inventory of Mental Health Quality Measures was funded by the Agency for Healthcare Research and Quality to (1) inventory process measures for assessing the quality of mental health care; (2) identify clinical, administrative, and quality domains where measures have been developed; and (3) identify areas where further research and development is needed. Among the 86 measures identified, most evaluated treatment of major mental disorders, for example, schizophrenia (24 percent) and major depression (21 percent). A small proportion focused on children (8 percent) or the elderly (9 percent). Domains of quality included treatment appropriateness (65 percent), continuity (26 percent), access (26 percent), coordination (13 percent), detection (12 percent), and prevention (6 percent). Few measures were evaluated for reliability (12 percent) or validity (3 percent). Measures imposing a lower burden were more likely to be in use (chi 2 = 4.41, p = .036). Further measures are needed to assess care for several priority clinical and demographic groups. Research should focus on measure validity, reliability, and implementation costs. In order to foster quality improvement activities and use of common measures and specifications for mental health care, the inventory of quality measures will be made available at www.challiance.org/cqaimh.

Adult↗

PubMed2000

Cytokine profiles in eye muscle tissue and orbital fat tissue from patients with thyroid-associated ophthalmopathy.

Eye muscle (EM) and retroorbital fat tissue are two major sites of involvement in thyroid-associated ophthalmopathy (TAO). Lymphocytic infiltration in these tissues is a prominent histological feature of TAO. We have investigated the cytokine gene profiles in EM and orbital fat (OF) tissues from patients with TAO. Total RNA was isolated from EM tissue of 14 patients and from OF tissues of 29 patients with TAO. Cytokine gene expression was assessed by RT-PCR using paired primers for interferon gamma (IFNgamma), tumor necrosis factor alpha (TNFalpha), interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-10, CD4, CD8, and glyceraldehyde-3-phosphate dehydrogenase. IFNgamma, TNFalpha, IL-1beta, and IL-6 messenger RNA (mRNA) were mainly detected in EM tissue, whereas IL-4 and IL-10 mRNA were detected in only one patient. On the other hand, in OF tissue, IL-4 and IL-10 mRNA were detected in 24% and 38% of the patients, respectively, and IFNgamma, IL-1beta, and IL-6 mRNA were less often detected compared with EM tissue. The enlargement of EM tissue as assessed by computed tomography correlated significantly with TNFalpha mRNA expression in EM tissue. The orbital volume was positively correlated with IL-6 mRNA expression and negatively correlated with IL-4 mRNA and IL-10 mRNA expression in OF tissue. These results suggest that T helper (Th) 1-like cytokines predominate in EM tissue in most patients and that the predominant cytokine profile in OF tissue varies from patient to patient. Both Th1-like and Th2-like immune responses may play roles in the development of two components of ophthalmopathy.

Adipose Tissue↗

PubMed2000

Heregulin regulates the actin cytoskeleton and promotes invasive properties in breast cancer cell lines.

The metastatic process requires changes in tumor cell adhesion properties, cell motility and remodeling of the extracellular matrix. The erbB2 proto-oncogene is overexpressed in approximately 30% of breast cancers and is a major prognostic parameter when present in invasive disease. A ligand for the erbB2 receptor has not yet been identified but it can be activated by heterodimerization with heregulin (HRG)-stimulated erbB3 and erbB4 receptors. The HRGs are a family of polypeptide growth factors that have been shown to play a role in embryogenesis, tumor formation, growth and differentiation of breast cancer cells. The erbB3 and erbB4 receptors are involved in transregulation of erbB2 signaling. The work presented here suggests biological roles for HRG including regulation of the actin cytoskeleton and induction of motility and invasion in breast cancer cells. HRG-expressing breast cancer cell lines are characterized by low erbB receptor levels and a high invasive and metastatic index, while those which overexpress erbB2 demonstrate minimal invasive potential in vitro and are non-tumorigenic in vivo. Treatment of the highly tumorigenic and metastatic HRG-expressing breast cancer cell line MDA-MB-231 with an HRG-neutralizing antibody significantly inhibited proliferation in culture and motility in the Boyden chamber assay. Addition of exogenous HRG to non-invasive erbB2 overexpressing cells (SKBr-3) at low concentrations induced formation of pseudopodia, enhanced phagocytic activity and increased chemomigration and invasion in the Boyden chamber assay. The specificity of the chemomigration response to HRG is demonstrated by inhibition with the anti-HRG neutralizing antibody. These results suggest that either HRG can act as an autocrine or paracrine ligand to promote the invasive behavior of breast cancer cells in vitro or thus may enhance the metastatic process in vivo.

Actins↗

PubMed2000

[Significance and expression of insulin-like growth factor II and its receptor in hepatocellular carcinogenesis].

OBJECTIVE: To provide information on the potential role of insulin-like growth factor II (IGF-II) and insulin-like growth factor II receptor (IGF-IIR) during different liver diseases and hepatocarcinogenesis. METHODS: Southern hybridization was used to detect HBV DNA integration in various kinds of liver tissues, and DNA-RNA in situ hybridization to observe and analyze the mRNA of IGF-II and IGF-II receptor in chronic hepatitis, cirrhosis and hepatocellular carcinoma (HCC). RESULTS: The expression of IGF-II and IGF-II receptor mRNA was observed not only in HCC, but also in chronic hepatitis and cirrhosis. An increasing gradient of IGF-II and IGF-IIR Mrna expression was in turn from chronic hepatitis (33. 3%), HCC (66.7%) to cirrhosis (72.0%). Strongly positive expression was found in liver cell dysplasia, regenerative nodules and poorly differentiated HCC cells. CONCLUSION: IGF-II and its receptor might play an important role in the development of HCC.

Adult↗

PubMed2000

Detection of transfusion transmitted virus in hepatic and extra hepatic tissues using in situ hybridization.

OBJECTIVE: To investigate the location, distribution and significance of transfusion transmitted virus (TTV) in the liver and extra hepatic tissues. METHODS: A 123 bp fragment of TTV DNA within ORF(2) was amplified by PCR reaction and cloned into PCR2.1 vector. DNA sequencing revealed that the inserted fragment was highly isogenous with Japan ABO11494 strain. The inserted fragment was labeled with digoxigenin. Segment of liver, spleen, kidney, stomach and intestine tissues from 22 patients dead of liver diseases were detected by in situ hybridization with this digoxigenin labeled TTV DNA probe. RESULTS: TTV DNA was detected in 8 livers, 4 kidneys, 3 spleens, 2 intestines, and 2 stomachs. The positive cells of TTV DNA in livers were higher than that in other tissues. No obvious pathological topographical relationship of tissue inflammatory reaction with positive cells was found. CONCLUSION: TTV can infect hepatic and ex-hepatic tissues and may cause persistent infection.

Adolescent↗

PubMed2000

Human neutrophil defensins selectively chemoattract naive T and immature dendritic cells.

Defensins, a family of cationic, structurally related, antimicrobial peptides, contribute to host defense by disrupting the cytoplasmic membrane of microbes. Here we show that human neutrophil defensins selectively induce the migration of human CD4+/CD45RA+ naive and CD8+, but not CD4+/CD45RO+ memory, T cells. Moreover, human neutrophil defensins are chemotactic for immature human dendritic cells derived from either CD34+ progenitors or peripheral blood monocytes. Upon maturation induced by treatment with tumor necrosis factor alpha (TNF-alpha), dendritic cells lose their responsiveness to human neutrophil defensins. The chemotactic effect of human neutrophil defensins on both T and dendritic cells is pertussis toxin-sensitive, suggesting that a G(ialpha) protein-coupled receptor is responsible. Human neutrophil defensins are also chemotactic for immature murine dendritic cells. These data suggest that, in addition to their antimicrobial role, human neutrophil defensins also contribute to adaptive immunity by mobilizing T cells and dendritic cells.

Adult↗

PubMed2000

Molecular cloning and expression of an inwardly rectifying K(+) channel from bovine corneal endothelial cells.

PURPOSE: To determine the presence of a putative inwardly rectifying K(+) channel in bovine corneal endothelial (BCE) cells and to characterize its molecular and electrophysiological properties. METHODS: An RT-PCR strategy was used to clone an IRK1 channel sequence from BCE mRNA. Northern blot analysis was used to confirm expression of this sequence in cultured BCE cells. Two-electrode voltage-clamp and whole-cell patch-clamp recordings were used to characterize the cloned channel expressed in Xenopus oocytes and the native channels in cultured BCE cells, respectively. RESULTS: A full-length (1284 bp) coding sequence that shares 99.7% nucleotide sequence and 100% amino acid sequence identity to bovine lens IRK1 (Kir2.1) was cloned. The authors designate this sequence BCE IRK1 or BCIRK1. Northern blot analysis indicated that BCIRK1 mRNA is expressed in cultured BCE cells with two major transcripts of 7.5 and 5.5 kb. BCIRK1 cDNA was subcloned into the vector, pcDNA3.1(-), and cRNA transcribed from the BCIRK1 cDNA clone was injected into Xenopus oocytes. Two-electrode voltage-clamp recordings from injected oocytes revealed inwardly rectifying K(+) currents that were blocked by external Ba(2+) and Cs(+) in a concentration- and voltage-dependent manner. Whole-cell patch-clamp recordings from dissociated cultured BCE cells revealed strongly inwardly rectifying K(+) currents with similar properties. CONCLUSIONS: Corneal endothelial cells express IRK1 (Kir2.1) inwardly rectifying K(+) channels. Consistent with the properties of IRK1 channels, BCIRK1 is likely involved in regulating membrane potential and possibly other cellular functions in corneal endothelial cells.

Amino Acid Sequence↗

PubMed2000

A meta-analysis of soyfoods and risk of stomach cancer: the problem of potential confounders.

It has been suggested that consumption of soyfoods may be associated with a reduction in risk of various cancers, including nonhormonally dependent cancers. The purpose of this meta-analysis was to examine the relationship between fermented and nonfermented soyfoods and risk of stomach cancer. We searched the reference lists of English language publications of diet and stomach cancer studies that were conducted in Asia or among Asians living in the United States or elsewhere between 1966 and 1999. All of the analytic epidemiological studies that obtained individual data on intake of soyfoods and presented risk estimates of the association between intake of soyfoods and risk of stomach cancer were identified and included in this review. Our pooled analysis of 14 studies with data on fermented soyfoods yielded an odds ratio/relative risk of 1.26 (95% confidence interval, 1.11-1.43) in association with high intake of such foods. In contrast, our pooled analysis of 10 studies with data on nonfermented soyfoods found an odds ratio/relative risk of 0.72 (95% confidence interval, 0.63-0.82) in association with high intake of these foods. However, further analyses suggest that fermented and nonfermented soyfoods may be associated with salt and fruit/vegetable intake, respectively; salt and fruit/vegetable intake are directly associated with stomach cancer risk. In almost all of the studies we reviewed, the possible confounding role of salt, fruit/vegetable, and other dietary factors had not been considered in the soyfood analyses. In conclusion, the role of soyfoods in the etiology of stomach cancer cannot be determined with confidence until the roles of potential confounders, including salt, fruit/vegetables, and other dietary factors, are more adequately adjusted for.

Adult↗

PubMed2000

[Study on the relationship of alteration and expression of p16 gene to pancreatic carcinoma].

OBJECTIVE: To directly investigate the effect of genetic alteration(homozygous deletion and point mutation) and expression of p16 gene on pancreatic carcinomas. METHODS: Thirty-five cases were analyzed for genetic alteration and expression of p16 gene by polymerase chain reaction(PCR), single strand conformation polymorphism(SSCP), DNA sequencing and immunohistochemical method. RESULTS: The analysis of pancreatic carcinoma for p16 gene revealed alteration in 19 of 35 cases, among which 12 pancreatic carcinomas had 522 bp homozygous deletion at least and 7 cases had two point mutations at the same site. One of them is 126th codon GTC --> AAT (Val126Asn); the other is 127th codon GCA --> GCG (A127A). The 3D (three-dimensional) structure of P16 protein determined by computer techniques according to PDB indicated that Val126Asn influenced the space structure of P16 protein and affected the function of P16 protein. Twelve cases revealed no P16 protein and 9 cases showed low level expression of P16 protein. CONCLUSION: The alteration of p16 gene and abnormal expression of P16 protein are significantly correlated with the biological behavior and clinical staging of pancreatic carcinoma and may hence be helpful to prognostication

Adult↗

PubMed2000

Developing a quality management system for behavioral health care: the Cambridge Health Alliance Experience.

The rapid pace of change in the health care system presents tremendous challenges for clinicians and managers charged with the delivery of mental health and substance abuse services. Declining reimbursement, new incentive structures, and increasing competition are placing unprecedented pressure on providers to deliver care efficiently. Regulatory scrutiny, consumer dissatisfaction, and a growing awareness of gaps between actual and ideal practice have led to intensifying pressure to improve quality. Yet system change has also presented new opportunities for managing cost and quality of care. Consolidation of facilities and practices into integrated networks, developments in information systems technology, and the emergence of models to facilitate change have led to the rise of "quality management," a framework for assessing and improving clinical, operational, and financial performance within a health care organization. This article reviews some of the precipitating factors and theoretical structures underlying quality management and then, through a case study of one organization's experience, describes the implementation of a quality management program in a behavioral health care delivery system. The case study emphasizes how theoretical frameworks were operationalized and how organizational structure and process were shaped to address challenges well known in quality management, such as authority, accountability, and follow-through. A multiphase model of quality management program development is formulated and used to provide context for this program's development.

Adolescent↗

PubMed2000

Effects of a 6-month vitamin intervention on DNA damage in heavy smokers.

Because their formation is associated with tumor development in specific tissues, DNA adducts have potential usefulness as intermediate end points in chemoprevention studies. To determine the efficacy of a combination of antioxidant vitamins (vitamins C and E and beta-carotene), a randomized clinical trial was conducted among heavy smokers using DNA damage as the end point. Immunological methods were used to measure polycyclic aromatic hydrocarbon-DNA adducts and oxidative DNA damage (8-oxo or hydroxydeoxyguanosine) in mononuclear and oral cells. A total of 121 subjects were randomized to the 6-month intervention and received either vitamins or placebo. Dropout rates were higher in the placebo than in the vitamin group; 65% of subjects in the vitamin group, but only 47% in the placebo group, provided specimens at 6 months. Plasma levels of all three antioxidants rose significantly in the vitamin group but not in the placebo group. All four measures of DNA damage decreased in both groups; the between-group differences were not statistically significant. These data do not provide clear evidence that antioxidant vitamin intake prevents DNA damage. However, the study demonstrates that DNA damage is a useful end point in chemoprevention trials.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2000

[The development of a computer-based visual field analyzer].

Visual field is one of the important visual functions; it is the extent of the visual field defect that can be employed in judging whether the visual function is impaired. The rapid achievements in computer technologies do provide an impulse for improvement of visual field detection, making possible the automatic, rapid, accurate, detailed and large-scaled visual field detection. This paper gives a thorough description about development of the visual field analyzer, model TEC-2A, which is based on PC windows platform, Visual Basic software developing tool, ISA peripheral circuits, standard Goldmann visual field half-ball and standard stimulus.

Adolescent↗

PubMed2000

Modulation of transforming growth factor beta to platelet-derived growth factor receptor-alpha of human osteoblasts.

OBJECTIVE: To investigate the mechanism and the significance of TGF beta in modulating the expression of Platelet-Derived Growth Factor Receptor-alpha (PDGFR-alpha) in human osteoblasts. METHODS: The osteoblasts were isolated from human fetal calvaria. The percentage of cell increase (PCI) in every 4 hours was calculated to demonstrate the proliferation of osteoblasts affected by PDGF-AA and TGF beta. The osteoblasts were cultured with TGF beta for 24 hours and with PDGF-AA for another 24 hours, and the cells proliferation was shown by PCI too. The osteoblasts were cultured with TGF beta for 24 h, and the PDGFR-alpha of the cells were measured by immunofluorescent analysis. RESULTS: PCI was increased by 48.2% and 22.4% after PDGF-AA and TGF beta were added into the medium for 24 hours respectively (P < 0.05), and PCI decreased after the removal of the two cytokines. Preincubated with TGF beta for 24 hours and then stimulated with PDGF-AA, PCI grew slowly. TGF beta downregulated the expression of the PDGFR-alpha. CONCLUSION: TGF beta can downregulate the mitogenesis of PDGF-AA by lowering the number of PDGFR-alpha.

Cell Division↗

PubMed2000

Intravesical immunotoxin as adjuvant therapy to prevent the recurrence of bladder cancer.

OBJECTIVE: To assess the intravesical application of immunotoxin as adjuvant therapy to prevent recurrence after tumor resection in bladder cancer patients. METHODS: An anti-human immunotoxin against bladder carcinoma, BDI-1-RT, was prepared and its in vitro targeting cytotoxicity estimated. The immunoreactivity of BDI-1-RT with human bladder cancer tissue of different grades and stages was detected by immunohistochemical analysis. After safety test, intravesical administration of BDI-1-RT was performed in 31 patients while mitomycin C (MMC) was used in 36 patients serving as a control group. The recurrence rates and side effects in both groups were recorded. In addition, the development of human anti-mouse antibodies (HAMA) was determined by ELISA, to assess the potential safety of this immunotoxin. RESULTS: In our study, BDI-1-RT had immunoreactivity with 81.6% of bladder transitional cell carcinomas. The immunoreactivity of BDI-1-RT correlated with tumor grade. High-grade carcinoma had stronger staining than low-grade (P < 0.05). There was no significant difference between the BDI-1-RT group (10%) and MMC group (19.3%) in recurrence rate (P > 0.05). Side effects, including systemic and local, were more frequent in the MMC group (11 of 36 patients versus 2 of 31, P < 0.05). HAMA was not detected in any of 7 patients. CONCLUSION: Immunotoxin may have considerable potential in the prophylaxis of bladder transition cell carcinoma.

Administration, Intravesical↗

PubMed2000

[To probe into the practicability of using the jaw position of eliminating TMJ clicks as the therapeutic position of repositioning splint].

OBJECTIVE: To evaluate that it was practicable to use the jaw position of eliminating TMJ clicks as the therapeutic position of repositioning splint and to probe into the therapeutic mechanism of repositioning splint. METHODS: 25 patients with reducible disc displacement were treated with repositioning splint. The therapeutic jaw position was the position without TMJ clicking, then verified by Arthrography. The treatment effect was observed. RESULTS: Among 25 cases, 19 discs were completely recaptured, 5 incompletely recaptured, 1 not recaptured. Once the splints inserted, the movements of disc-condyle complex were smooth. After treatment finished, the opening types were improved, the clicks were lessened. CONCLUSIONS: It's practicable to use the jaw position of eliminating clicks as the treatment jaw position of repositioning splint. The therapeutic mechanism of repositioning splint may be that it altered the relationship of disc and condyle and improved their movement. That was favorable to fibrize the retrodiscal tissue and to strengthen the posterior band of disc.

Adolescent↗

PubMed2000

[Effect of yimai jiangya extract on platelet activation and fibrinolytic activity and angiotensin II in aged patients with essential hypertension].

OBJECTIVE: To observe the effect of Yimai Jiangya extract (YMJYE) on platelet alpha-granule membrane protein (GMP-140), tissue-type plasminogen activator (t-PA) and its inhibitor (PAI), angiotensin II (AngII) in aged patients with essential hypertension (EH) of stage 2 caused by Qi deficiency and blood stasis. METHODS: Radioimmunoassay (RIA) and colorimetric analysis were used to examine the levels of GMP-140, t-PA, PAI and AngII before and after treatment with YMJYE in 42 aged patients (treated group), compared with that of 30 aged patients before and after treatment with captopril (control group) and 30 aged healthy subjects (healthy group). RESULTS: Before treatment, GMP-140, PAI and AngII were significantly higher (P < 0.01), and t-PA were obviously lower (P < 0.01) in the treated and the control group compared with those in the healthy group. After treatment, the improvement of GMP-140, t-PA, PAI and AngII in the treated group were obvious (P < 0.05, P < 0.01). The improvement of GMP-140, t-PA, PAI in the treated group was more significant than that of control group (P < 0.05, P < 0.01), while the improvement of AngII in the treated group was worse than that of the control group (P < 0.01). After treatment, there was insignificant changes about the levels of blood pressure between the treated group and the control group (P > 0.05). CONCLUSIONS: In the aged patients, GMP-140, PAI and AngII were increased, t-PA reduced. The effects of YMJYE in inhibiting platelet activation and improving fibrinolytic activity were better than that of captopril. These findings indicated that the mechanisms of inhibiting platelet activation and improving fibrinolytic activity and lowering blood pressure of YMJYE were correlated with decreasing the levels of AngII, but other mechanisms may also exist.

Aged↗

PubMed2000

[Relations of chemotherapy-induced tumor necrosis to plasma platin concentration and primary tumor temperature in patients with osteosarcoma in the lower extremities treated by hyperthermic isolation limb perfusion with cisplatin].

OBJECTIVES: To study the relations of chemotherapy-induced tumor necrosis to plasma concentration of platin and primary tumor temperature in hyperthermic isolation limb perfusion (HILP) with cisplatin, and to investigate the correlation between the tumor necrosis rate and the relapse-free survival (RFS). METHODS: Fifteen patients with II B osteosarcoma in the lower extremities were treated with neoadjuvant chemotherapy. Among them, 10 were male and 5 female. The average age was 18 years (ranging from 13 to 29). Chemotherapy included a single bonus dose of HILP with cisplatin (CDDP, 15 mg/m(2)). The plasma concentration of platin and the tumor temperature in the affected limb were measured during the course of the HILP with CDDP. Limb salvage surgery was performed in 9 patients and amputation in 6. After surgery, serial sections of the excised tumor specimens were made to determine the tumor necrosis rate. All of the patients were followed up for more than 5 years. RESULTS: The highest attained tumor temperature was between 41.4 degrees C - 43.0 degrees C (mean 42.3 degrees C +/- 0.46 degrees C), and the platin concentration ranged from 4.56 microg/mL to 14.66 microg/mL (mean 8.93 microg/mL +/- 3.16 microg/mL) during the course of HILP with CDDP. Thirteen patients with a necrosis rate of over 90% were well responded, and the remaining two with a necrosis rate 87.2% and 86.3% were poor responded. Eight patients remained tumor-free for 5 years. Primary tumor temperature and platin concentration were significantly related to the tumor necrosis rate (P = 0.001 and P < 0.001, respectively). No significant correlation was noted between the long-term survival rate and the three parameters in the regression analysis. CONCLUSIONS: HILP with CDDP is useful in the treatment of primary osteosarcoma. Increased tumor necrosis ensure a successful surgical excision of tumor. HILP however is still limited to the patients who are not candidates for lime salvage surgery, because the same condition of high temperature and high concentration of platin are not applicable to distant metastasis.

Adolescent↗