Biomedical subjects

M Bai

Publications and source records attributed to M Bai.

At least 19 recordsLinked to original sources

PubMed2006

Air quality improvement estimation and assessment using contingent valuation method, a case study in Beijing.

The aim of the paper is to estimate and assess residents' willingness to pay to improve air quality in the urban area of Beijing using the Contingent Valuation Method (CVM). The mean willingness to pay (WTP) for a 50% reduction of harmful substances in the air was 143 CNY per household per year, and the total WTP of the residents in the study area was 336 million CNY per year. As a proportion of household annual income, the mean WTP amounted to 0.7%. Four socio-economic variables were found to have significant impacts on residents' willingness to pay. The analysis results illustrated that WTP increases with income and education level, and decreases with household population and age. The willingness was larger for residents in the urban districts than those in the suburban districts. It was found that most of the protest bids lay on interviewees' incomplete perception of the values of environmental amenity. The influence of household income on people's willingness to pay illustrated in this study reflects a causal force of Beijing's transition to market economy that households created to have disposable income are more likely to care about environmental quality. The results of this study strike an optimistic note on the possibility of measuring the total economic value of environmental quality improvement by using the CVM in China. Suggestions on implication of the CVM for both academics and policy makers are provided in the paper.

Air↗

PubMed2006

Polarized proton collisions at 205 GeV at RHIC.

The Brookhaven Relativistic Heavy Ion Collider (RHIC) has been providing collisions of polarized protons at a beam energy of 100 GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the intrinsic spin resonances beyond 100 GeV are about a factor of 2 stronger than those below 100 GeV making it important to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were first accelerated to the record energy of 205 GeV in RHIC with a significant polarization measured at top energy in 2005. This Letter presents the results and discusses the sensitivity of the polarization survival to orbit distortions.

Journal Article↗

PubMed2005

Psychological distress and personality traits in early rheumatoid arthritis: A preliminary survey.

OBJECTIVES: To investigate psychiatric manifestations, personality traits, and ego mechanisms of defense involved in early rheumatoid arthritis (RA). METHODS: Twenty-two unselected early RA outpatients with disease duration less than 1 year participated in the study. The majority of participants were females (72.7%), married (81.8%), aged 51.0+/-14.6 years. Thirty-four subjects matched for age, sex and educational level served as "healthy" controls. General Heath Questionnaire, Symptom Distress Checklist, Defense Style Questionnaire and Hostility and Direction of Hostility Questionnaire were used; disease activity was estimated by disease activity for 28-joint indices score. RESULTS: Seven patients (31.8%) presented psychological distress scores indicative of possible psychiatric caseness, expressing obsessive-compulsive symptoms and depression, as compared to six (17.6%) of controls. Social dysfunction distress and somatization were prominent psychiatric manifestations in early RA group. Early RA patients tend to adopt a less adaptive defense style than controls. Although disease activity was not correlated to psychological distress, a significant association between disease activity and patients' defensive style was observed: as the disease is exacerbated, there was a shift from "non-adaptive" to "immature image distorting or borderline" defense style, suggesting a rather fragile underlying personality structure. CONCLUSION: Psychological distress is a relatively common experience in early RA. Social dysfunction, along with the less adaptive defense style, which under the stress of the disease exacerbation turns to "borderline", underlines the importance of a careful assessment and consultation in early RA patients in order to face the distress shortly after diagnosis and highlights potential risk factors for future adaptation to exacerbations of the disease.

Adaptation, Psychological↗

PubMed2005

Laryngeal involvement in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting the synovial membrane, which causes joint damage and bone destruction. Extra-articular manifestations are numerous, involving multiple organ systems. Rheumatoid nodules are common extra-articular findings occurring in 20% RA patients. They develop most commonly in pressure areas (elbows and finger joints) and may occasionally affect internal organs including pleura, lungs, meninges, larynx, and others. Furthermore, RA affects the ear, nose, and throat, causing various otorhinolaryngological symptoms. In this report we describe two patients with RA and laryngeal involvement, mostly rheumatoid nodule formation, with a review of the literature.

Aged↗

PubMed2005

Multiple brown tumors of the ribs simulating malignancy.

Bone disease associated with primary hyperparathyroidism, known as osteitis fibrosa cystica, is now very rarely encountered, since the parathyroid disorder is most often diagnosed at the early stage of asymptomatic hypercalcemia. Here, we report the case of a patient with multiple pleural-based masses and hypercalcemia, which led to the presumptive diagnosis of malignancy. However, histological and laboratory data were consistent with the development of brown tumors of the ribs due to underlying severe hyperparathyroidism.

Aged↗

PubMed2005

Clinical correlation of bone marrow microvessel density in essential thrombocythemia.

The aim of this study was to investigate the prognostic relevance of angiogenesis expressed as bone marrow microvessel density (MVD) in 40 patients with essential thrombocythemia (ET). Bone marrow MVD was visualized in paraffin tissue sections using immunohistochemical staining for CD34 protein. Increased MVD of bone marrow specimens was not significantly correlated with clinical (sex, age, microvascular disturbances, liver and spleen size, complications, treatment or no before biopsy), laboratory (peripheral blood count), bone marrow histopathological parameters (cellularity, megakaryocyte clumping and reticulin fibrosis) and overall survival. These preliminary findings suggest that angiogenesis has no prognostic value in patients with ET.

Adult↗

PubMed2004

Sinus histocytosis with massive lymphadenopathy (Rosai-Dorfman disease) in a patient with primary Sjogren's syndrome.

Sinus histocytosis with massive lymphadenopathy is a rare disease that has been described by Rosai and Dorfman. It is characterized by massive, cervical lymphadenopathy, with extranodal manifestations in about 40% of patients. It occurs as a distinct entity, never associated with other diseases, and in most cases the prognosis is good. Lymphadenopathy is also a frequent sign of patients with primary Sjogren's syndrome (SS), usually associated with disease activity or concurrent infection. However, excessive lymphadenopathy in SS patients is a sign of lymphoproliferative disorder development. In this report, we describe a patient with primary SS, and excessive lymphadenopathy and splenomegaly who developed Rosai-Dorfman disease, and we discuss the possible aetiopathophysiological mechanism linking these two entities.

Biopsy, Needle↗

PubMed2004

Angiogenesis in chronic myeloproliferative diseases detected by CD34 expression.

Increased bone marrow angiogenesis estimated as bone marrow microvessel density (MVD), or as serum angiogenic factor levels and/or immunohistochemical expression of these factors in bone marrow biopsy has been demonstrated in a variety of hematological disorders including chronic myeloproliferative diseases (MPDs). The aim of this study was to investigate the MVD in 25 cases of myelofibrosis with myeloid metaplasia (MMM). MVD was estimated by CD34 immunohistochemical expression in bone marrow biopsies. A control group of 27 patients without bone marrow disease, eight cases of polycythemia vera (PV), 41 cases of essential thrombocythemia (ET) and nine cases of chronic myeloid leukemia (CML) were also studied. Moreover, in cases with MMM, MVD was correlated with clinical, laboratory, histological parameters and the outcome of the patients. Our study confirmed a significantly higher degree of angiogenesis in MMM, PV, ET and CML compared with controls (P < 0.001, P = 0.0007, P < 0.001 and P = 0.0008, respectively). Angiogenesis was higher in MMM than PV, ET and CML cases (P < 0.001, P < 0.001 and P = 0.008). Increased angiogenesis was correlated with hypercatabolic symptoms in MMM patients (P = 0.009). No correlation with other clinicopathological parameters or clinical outcome was found. However, definitive conclusions regarding the prognostic value of increased angiogenesis may require additional follow-up and a larger group of patients.

Aged↗

PubMed2003

Increased expression of the bcl6 and CD10 proteins is associated with increased apoptosis and proliferation in diffuse large B-cell lymphomas.

There is increasing evidence that bcl6 and CD10 expression may be related to apoptosis and cell cycle progression. Therefore, 79 cases of de novo diffuse large B-cell lymphomas were studied for the expression of bcl6 and CD10 proteins in relation to 1) the apoptotic index; 2) the proliferation-associated proteins Ki67, cyclin A, and cyclin B1; and 3) the expression of the bcl2, p53, Rb, p16, and p27 proteins. Expression of bcl6, CD10, and bcl2 proteins was found in 54/79 (68%), 28/79 (35%), and 47/74 (63%) cases, respectively. The bcl6/CD10 patterns were as follows: bcl6+/CD10+ (26 cases, 32%), bcl6+/CD10- (28 cases, 33%), bcl6-/CD10- (23 cases, 31%), and bcl6-/CD10+ (2 cases, 4%). Significant positive correlations were found between bcl6/Ki67 (r =.328, P =.003), bcl6/cyclin A (r =.265, P =.018), bcl6/apoptotic index (r =.327, P =.010), CD10/Ki67 (r =.296, P =.008), and CD10/apoptotic index (r =.397, P =.001). In addition, high expression of bcl6 showed significant correlation with negative (null/low) bcl2 expression (chi(2) test, P =.002). The above findings indicate that increased expression of the bcl6 and CD10 proteins is associated with increased apoptosis and proliferation in diffuse large B-cell lymphomas. The association between increased bcl6 expression and enhanced apoptosis might be due, at least in part, to the null/low bcl2 expression because previous in vitro data showed that bcl6 overexpression induces apoptosis accompanied by bcl2 and bcl-xl downregulation. Moreover, significant correlation was found between increased apoptotic index and the bcl6+/CD10+ pattern (t test: P =.014, Mann-Whitney test: P =.046). This finding and the positive correlation of the apoptotic index with bcl6 and CD10 expression may be related to previous results showing that the expression of these proteins has favorable effects on the clinical outcome of diffuse large B-cell lymphomas.

Apoptosis↗

PubMed2003

Expression and characterization of the extracellular Ca(2+)-sensing receptor in melanotrope cells of Xenopus laevis.

The extracellular Ca(2+)-sensing receptor (CaR) is expressed in many different organs in various species, ranging from mammals to fish. In some of these organs, this G protein-coupled receptor is involved in the control of systemic Ca(2+) homeostasis, whereas in other organs its role is unclear (e.g. in the pituitary gland). We have characterized the CaR in the neuroendocrine melanotrope cell of the intermediate pituitary lobe of the South African clawed toad Xenopus laevis. First, the presence of CaR mRNA was demonstrated by RT-PCR and in situ hybridization. Then it was shown that activation of the CaR by an elevated extracellular Ca(2+) concentration and different CaR-activators, including L-phenylalanine and spermine, stimulates both Ca(2+) oscillations and secretion from the melanotrope. Furthermore, it was revealed that activation of the receptor stimulates Ca(2+) oscillations through opening of voltage-operated Ca(2+) channels in the plasma membrane of the melanotropes. Finally, it was shown that the CaR activator L-phenylalanine could induce the biosynthesis of proopiomelanocortin in the intermediate lobe. Thus, in this study it is demonstrated that the CaR is present and functional in a defined cell type of the pituitary gland, the amphibian melanotrope cell.

Animals↗

PubMed2003

Expression of cyclin D3 and cyclin E and identification of distinct clusters of proliferation and apoptosis in diffuse large B-cell lymphomas.

In the present study 79 cases of de novo Diffuse Large B-cell Lymphomas (DLBCL) were studied in order: a) to analyse the expression of cyclin D3, cyclin E and cyclin D1 in relation to other proliferative features (expression of Ki67, cyclin A and cyclin B1), the apoptosis status and the expression of p53, Rb, p16 and p27; and b) to determine whether distinct clusters of proliferation and apoptosis could be identified in DLBCL. Overexpression of cyclin D3 and cyclin E was found in 35/79 (43%) and 18/79 (22%) cases, respectively, whereas overexpression of cyclin D1 was not detected in any case. In most cases (39/46) overexpression of cyclin D3 and cyclin E was mutually exclusive possibly reflecting different underlying pathways inducing deregulated expression of these cyclins. In most cases (29/35) overexpression of cyclin D3 was mutually exclusive with Rb/p16 aberrant expression status supporting an oncogenic role for cyclin D3 and suggesting that the pathogenetic effect of cyclin D3 overexpression occurs through perturbation of the Rb1 pathway. Combined alterations of the P53 and the Rb/p16/cyclin D3 expression status were significantly associated with higher mean values of cyclin A (p=0.023) and cyclin B1 (p=0.033) indicating that concurrent impairment of the p53 and Rb1 pathways induces increased tumour cell proliferation in DLBCL. Cluster analysis of the apoptosis and the proliferation status permitted separation of DLBCL into distinct groups with low (44 cases) and high (18 cases) apoptotic activity and into distinct groups with low (32 cases), intermediate (36 cases) and high (11 cases) proliferative activity. The identification of distinct clusters with respect to the proliferation and the apoptosis status indicates that groups with distinct cellular kinetic properties can be defined in the histological group of DLBCL.

Apoptosis↗

PubMed2003

Solitary extramedullary plasmacytoma of the maxillary sinus. Case report.

Solitary extramedullary plasmacytomas are rare tumors that often affect head and neck region. Because of the non-specific associated symptomatology, they frequently are misdiagnosed. We briefly describe a 69-year-old woman who developed solitary plasmacytoma in the left maxillary sinus and was initially treated as having sinusitis. We also report the diagnostic work-up that is necessary to establish a correct diagnosis in such cases. This case highlights that an appropriate investigation for neoplastic disease should be performed in patients presenting with persistent symptoms that resemble those of sinusitis, especially if these do not resolve after conservative medical treatment.

Aged↗

PubMed2002

Measurement of analyzing power for proton-carbon elastic scattering in the coulomb-nuclear interference region with a 22-GeV/c polarized proton beam.

The analyzing power for proton-carbon elastic scattering in the Coulomb-nuclear interference region of momentum transfer, 9.0x10(-3)<-t<4.1x10(-2) (GeV/c)(2), was measured with a 21.7 GeV/c polarized proton beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory. The ratio of hadronic spin-flip to nonflip amplitude, r(5), was obtained from the analyzing power to be Rer(5)=0.088+/-0.058 and Imr(5)=-0.161+/-0.226.

Journal Article↗

PubMed2002

Polyvalent cation receptor proteins (CaRs) are salinity sensors in fish.

To determine whether calcium polyvalent cation-sensing receptors (CaRs) are salinity sensors in fish, we used a homology-based cloning strategy to isolate a 4.1-kb cDNA encoding a 1,027-aa dogfish shark (Squalus acanthias) kidney CaR. Expression studies in human embryonic kidney cells reveal that shark kidney senses combinations of Ca(2+), Mg(2+), and Na(+) ions at concentrations present in seawater and kidney tubules. Shark kidney is expressed in multiple shark osmoregulatory organs, including specific tubules of the kidney, rectal gland, stomach, intestine, olfactory lamellae, gill, and brain. Reverse transcriptase-PCR amplification using specific primers in two teleost fish, winter flounder (Pleuronectes americanus) and Atlantic salmon (Salmo salar), reveals a similar pattern of CaR tissue expression. Exposure of the lumen of winter flounder urinary bladder to the CaR agonists, Gd(3+) and neomycin, reversibly inhibit volume transport, which is important for euryhaline teleost survival in seawater. Within 24-72 hr after transfer of freshwater-adapted Atlantic salmon to seawater, there are increases in their plasma Ca(2+), Mg(2+), and Na(+) that likely serve as a signal for internal CaRs, i.e., brain, to sense alterations in salinity in the surrounding water. We conclude that CaRs act as salinity sensors in both teleost and elasmobranch fish. Their tissue expression patterns in fish provide insights into CaR functions in terrestrial animals including humans.

Amino Acid Sequence↗

PubMed2001

In vivo cell kinetics in breast carcinogenesis.

BACKGROUND: Disruption of the balance between apoptosis and proliferation is considered to be an important factor in the development and progression of tumours. In the present study we determined the in vivo cell kinetics along the spectrum of apparently normal epithelium, hyperplasia, preinvasive lesions and invasive carcinoma, in breast tissues affected by fibrocystic changes in which preinvasive and/or invasive lesions developed, as a model of breast carcinogenesis. MATERIALS AND METHODS: A total of 32 areas of apparently normal epithelium and 135 ductal proliferative and neoplastic lesions were studied. More than one epithelial lesion per case were analyzed. The apoptotic index (AI) and the proliferative index (PI) were expressed as the percentage of TdT-mediated dUTP-nick end-labelling (TUNEL) and Ki-67-positive cells, respectively. The PI/AI (P/A index) was calculated for each case. RESULTS: The AIs and PIs were significantly higher in hyperplasia than in apparently normal epithelium (P = 0.04 and P = 0.0005, respectively), in atypical hyperplasia than in hyperplasia (P = 0.01 and P = 0.04, respectively) and in invasive carcinoma than in in situ carcinoma (P < 0.001 and P < 0.001, respectively). The two indices were similar in atypical hyperplasia and in in situ carcinoma. The P/A index increased significantly from normal epithelium to hyperplasia (P = 0.01) and from preinvasive lesions to invasive carcinoma (P = 0.04) whereas it was decreased (non-significantly) from hyperplasia to preinvasive lesions. A strong positive correlation between the AIs and the PIs was found (r = 0.83, P < 0.001). CONCLUSION: These findings suggest accelerating cell turnover along the continuum of breast carcinogenesis. Atypical hyperplasias and in situ carcinomas might be kinetically similar lesions. In the transition from normal epithelium to hyperplasia and from preinvasive lesions to invasive carcinoma the net growth of epithelial cells results from a growth imbalance in favour of proliferation. In the transition from hyperplasia to preinvasive lesions there is an imbalance in favour of apoptosis.

Adult↗

PubMed2001

Interleukin 18 transfection enhances antitumor immunity induced by dendritic cell-tumor cell conjugates.

Dendritic cell (DC)-based tumor vaccine represents a promising approach to the immunotherapy of malignant tumors. We prepared a novel type of DC-based vaccine, stable conjugates of DCs and EL4 cells transduced with cDNA of OVA (E.G7). Immunization with DC-E.G7 conjugates led to generation of T helper (Th) 1 cytokine-producing cells, antigen-specific CD8(+) T cells, and strong antitumor immunity that is dependent on both CD4(+) T cells and CD8(+) T cells. To further increase the potency of the vaccine, interleukin 18-transfected DCs were used to prepare the IL18DC-E.G7 conjugates. Immunization with such conjugates significantly increased the production of Th1 cytokine-producing cells and the number of antigen-specific CD8(+) T cells, as well as stronger antitumor immunity. Furthermore, the increased Th1 cytokine production and stronger antitumor effect were not observed in mice depleted of IFN-gamma. These data indicated that DC-tumor cell conjugates are a potent tumor vaccine. Interleukin 18 can be administrated using gene-transfected cells and enhances antitumor immunity, which is mainly mediated by IFN-gamma.

Animals↗

PubMed2001

Serum levels of IL-6 and its soluble receptor (sIL-6R) in Waldenström's macroglobulinemia.

BACKGROUND: Interleukin-6 (IL-6) is a multifunctional cytokine that plays roles in the immune response, inflammation and hematopoiesis. Serum IL-6 levels have reported to reflect disease severity and high tumor burden in multiple myeloma (MM) patients and to correlate with several other laboratory parameters. Serum-soluble IL-6 receptor (sIL-6R) plays an agonist role in IL-6 signaling, enhancing its biological activity tenfold. PURPOSE-METHODS: We measured IL-6 and sIL-6R levels in 11 patients (7 male, 4 female, mean age 66.9 yr) with Waldenström's macrobulinemia (WM) using a commercially available enzyme-linked immunoassay in order to investigate their biological role and to find any possible relationship with disease severity, tumor burden or response to treatment. RESULTS: Serum IL-6 and sIL-6R concentrations at diagnosis were significantly higher than in healthy controls (Mann Whitney U-test, p < 0.001 and p < 0.01, respectively). Patients who were effectively treated had a significant reduction in IL-6 levels (p = 0.017). With regard to sIL-6R levels, no specific tendency was observed. In some of the responsive patients the levels increased whereas in others they decreased. No correlation was found between IL-6 and sIL-6R levels at diagnosis (p = 0.9, r = 0.036) or after treatment (p = 0.083, r = 0.3). CONCLUSIONS: Our results suggest that IL-6 may be a marker reflecting tumor burden, disease severity and response to treatment in WM. With regard to sIL-6R, we believe that it does not seem to be of much value, and its role remains to be clarified. However, future studies are needed to confirm and further extend the present results.

Adult↗

PubMed2001

Low expression of p27 protein combined with altered p53 and Rb/p16 expression status is associated with increased expression of cyclin A and cyclin B1 in diffuse large B-cell lymphomas.

The expression of the cyclin-dependent kinase inhibitor (CDKI) p27 protein was investigated in relation to (1) the expression of the cell cycle regulators p53, Rb and p16 and (2) the proliferation profile as determined by the expression of Ki67, cyclin A, and cyclin B1 in 80 cases of de novo diffuse large B-cell lymphomas (DLBCL). P27 expression was low/null in large tumor cells in 58/80 cases and intermediate/high in 22/80 cases. Increased expression of p53 protein was observed in 39/80 cases. Decreased expression of Rb and p16 proteins was mutually exclusive and was observed in 5/80 and 14/80 cases, respectively. The analysis of the p27 expression status (low/null versus intermediate/high) with respect to the p53 and/or Rb/p16 expression status showed that low/null p27 expression was significantly correlated with increased p53 expression (P =.018) and showed a strong trend for correlation with concurrent increased p53 expression and decreased Rb or p16 expression (P =.050). These findings suggest a tendency for concurrent alterations of the cell cycle regulators p27, p53, and Rb or p16 in DLBCL, which might result in impaired tumor growth control. Indeed, the analysis of the combined p27/p53/Rb/p16 expression status with respect to the proliferation profile showed that (1) three alterations in the combined p27/p53/Rb/p16 status (i.e., low/null P27 expression, increased expression of p53, and decreased expression of Rb or p16) were significantly correlated with increased expression of cyclin B1 (P =.005) and (2) two or three alterations were significantly correlated with increased expression of cyclin A (P =.014). These findings suggest combined impairment of a complex cell-cycle control network involving the CDK inhibitor p27, the P53 pathway, and the Rb1 pathway, which exerts a cooperative effect resulting in enhanced tumor cell proliferation.

Analysis of Variance↗