PubMed Health⌕ Search

Biomedical subjects

K Qiu

Publications and source records attributed to K Qiu.

12 recordsLinked to original sources
PubMed2006

Biodegradable porous calcium polyphosphate scaffolds for the three-dimensional culture of dental pulp cells.

AIM: To develop a three-dimensional culture model of human dental pulp cells (DPCs) with biodegradable porous calcium polyphosphate (CPP) scaffolds. METHODOLOGY: Human DPCs were isolated from three donors. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate the cytotoxicity of CPP compared with hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP). Values were analysed using unpaired t-tests. Cells were seeded onto porous CPP scaffolds with pore sizes in the range of 200-300 microm. The nature of cellular adaptation in the three-dimensional culture model was then evaluated visually by scanning electronic microscopy (SEM) and confocal laser scanning microscopy (CLSM). The apoptotic property of cells on the scaffolds was also assessed by DNA staining with CLSM. RESULTS: The cytotoxicity assay indicated that there was no significant difference between CPP and HA for each donor's original cells (P>0.05). Calcium polyphosphate had no cytotoxic effect on DPCs, whilst SEMs showed that cells successfully adhered to CPP scaffolds and spread amongst pores. On the cell surface, fine processes and matrix secretory granules were found. Confocal laser scanning microscopy showed that cells took on a three-dimensional structure with signs of vitality. CONCLUSION: Porous CPP scaffolds are promising for the establishment of a three-dimensional culture model of DPCs.

Apoptosis↗
PubMed2001

[Experimental and mechanism analyses on HCl emission control during PVC combustion in fixed beds].

Incineration of chloridated plastic (PVC) in solid wastes contributes much to HCl pollutant in air environment. The characteristics of HCl emissions and reduction during PVC combustion were conducted in a nearly isothermal, externally heated, horizontal quartz-tube reactor. With increasing temperature from 700 to 900 degrees C, the conversion of HCl increased leniently from 82.5% to 88.3%. High excess air factor enhanced a small amount of HCl existing in form of Cl2. The calcium-based sorbents including CaCO3, Ca(OH)2, Ca(CH3COO)2 exhibited high HCl capture efficiencies from 68% to 79%, while magnesium-based sorbent less than that of 3%. Influences of operational variables, i.e., size of sorbent, Ca/Cl molar ratio and combustion fume compositions, on the HCl reduction were discussed. From a point of view of equilibrium constant of dechloridization reaction the experimental results were explained in detail.

Hot Temperature↗
PubMed2000

[Phacoemulsification in white cataract].

OBJECTIVE: To evaluate the value and technique of Phacoemulsification in white cataract. METHODS: Ninty eyes of senile cataract were divided into two groups by the density of the nuclei. Different operative technique was done in two groups. RESULTS: The success rate of the continuous curvilinear capsulorhexis was 88.9%. Seventy five eyes have got the visual acuity over 0.5 on the first day after the operation. There was significant difference between two groups. The complications of operation were mild corneal edema and posterior capsule tear. CONCLUSIONS: It's difficult to complete the phacoemulsification of white cataract. The surgeons are required the skillful technique and experience. However, phacoemulsification is valuable in white cataract.

Adult↗
PubMed1997

Epstein-Barr virus in gastric carcinoma in Suzhou, China and Osaka, Japan: association with clinico-pathologic factors and HLA-subtype.

Information on geographic differences of Epstein-Barr virus (EBV) positivity and association with HLA in gastric carcinoma are limited. Therefore, the association of gastric carcinoma with EBV was examined in 118 patients from Suzhou, China, where the incidence of nasopharyngeal carcinoma (NPC) is high, and in 216 patients from Osaka, Japan, where the incidence of NPC is low, NPC being one of the EBV-associated carcinomas. Expression of HLA-A2 was also examined in some of these cases. The EBV genome was evidenced by PCR and in the tumor cells by in situ hybridization in 7/90 and 9/151 of cases from Suzhou and Osaka, respectively. Immunohistochemistry revealed that cancer cells in all cases with EBV did not express latent membrane protein-I. Type A was found in all cases positive for EBV. Among several histologic and clinical factors, only age of patients showed a correlation with EBV positivity: patients over 60 showed a higher frequency than patients below 60 years of age (p < 0.05). Typing of the HLA-A locus was possible in 16 cases positive for the EBV genome: 3 of 4 cases from Suzhou and 4 of 7 from Osaka were positive for HLA-A2 products. Severe lymphoid cell infiltration was found in 2 of 7 cases and 1 of 4 cases with and without the HLA-A2 type, respectively. The reported frequency of EBV positivity in Chinese living in Taiwan and in Japanese living in Hawaii is higher than in Suzhou, China, and Osaka, Japan, respectively. Our findings suggest that EBV association with gastric carcinoma is influenced by environmental and cultural factors.

Adenocarcinoma↗
PubMed1997

Epstein-Barr virus in lymphoproliferative diseases in the sino-nasal region: close association with CD56+ immunophenotype and polymorphic-reticulosis morphology.

Association between Epstein-Barr virus (EBV) and nasal T-cell lymphoma (NTL) has been demonstrated. NTL has 2 types of histologic figures: one is ordinary non-Hodgkin's lymphoma (NHL) with monomorphous proliferation, and the other is polymorphic-reticulosis (PR) morphology. The presence of the EBV genome and its sub-types (A and B) were examined on paraffin-embedded specimens from 36 cases of sino-nasal lymphomas (SNL) collected from Seoul, Republic of Korea, where the frequency of NTL is high. Patients' ages ranged from 2 to 74 years (median 54 years) with a male-to-female ratio of 2.5:1. Immunophenotypically, 8 cases were B-cell type, 11 were T-cell type with CD56-, 14 were CD56+ type, and 3 were null-cell type. Five of 11 cases with ordinary NHL of T-cell type and 9 of 14 cases with PR were CD56+. The EBV genome was found by polymerase chain reaction (PCR) and in the tumor cells by in situ hybridization (ISH) in 1 of 4 B-cell type (25%), 5 of 10 T-cell type (50%), 11 of 13 CD56+ type (85%), and in both of null-cell type (100%). Of 16 cases with PR morphology, 15 (94%) were positive for the EBV genome. All of the 5 NTLs of ordinary NHL with CD56- were negative for EBV. Concerning the sub-type of EBV, 16 cases had type A, while none had type-B EBV. These findings suggest that NTL comprises 2 groups: EBV-positive NTLs are CD56+ and/or histologically PR, and EBV-negative NTLs are CD56- and histologically ordinary NHL. The current results on Korean patients, together with earlier studies on Japanese and Malaysian patients, have shown the predominance of type-A EBV in sino-nasal lymphoma in Asia.

Adolescent↗
PubMed1995

Local projections of GABAergic neurons in the dentate gyrus and CA1 region in the rat hippocampal formation.

Using retrograde transport of wheat germ agglutinin conjugated colloidal gold (WGA-gold) combined with immunoreactivity for glutamate decarboxylase (GAD), a specific synthesizing enzyme for gamma-aminobutyric acid (GABA), local projections of GABAergic neurons in the dentate gyrus and CA1 were examined. In the hilus of the dentate gyrus, it was found that GABAergic neurons in the granule cell layer projected to the ipsilateral upper leaf of the molecular layer, with a mediolateral extension of more than 1.2 mm and a rostrocaudal extension of over 0.8 mm. Non-GABAergic neurons in nearly the entire hilar area were found to project to the ipsilateral upper leaf of the molecular layer. In the dorsal CA1 region, GABAergic neurons in the stratum pyramidale and radiatum converged onto the ipsilateral stratum pyramidal/oriens, with a mediolateral extension of over 1 mm and a rostrocaudal extension of over 0.7 mm. These results provide direct evidence that in both the dentate gyrus and CA1, GABAergic interneurons from a fairly large field converge onto a very small target area. This suggests that the output signals from GABAergic neurons in the dentate gyrus and CA1, and non-GABAergic neurons in the dentate gyrus, may propagate beyond the anatomical limits contained in conventional slice preparations of the hippocampal formation.

Animals↗
PubMed1992

Limited cell-cycle dependence of the merocyanine 540-sensitized photoinactivation of L1210 leukemia cells.

L1210 leukemia cells were synchronized by a double thymidine block technique and then characterized with regard to their susceptibility to merocyanine 540 (MC540)-sensitized photoinactivation. Cells harvested 5 (G2/M phase) h after release from the second thymidine block were most susceptible to MC540-sensitized photoinactivation followed, in order of decreasing sensitivity, by cells harvested 2 (S phase) h and by cells harvested 7 (G1 phase) h after release from the second block. The expression of dye-binding sites changed very little during the cell cycle.

Animals↗
PubMed1992

Merocyanine 540-sensitized photoinactivation of leukemia cells: effects of dose fractionation.

The differential sensitivity to merocyanine 540 (MC540)-sensitized photoirradiation of leukemia cells, selected solid tumor cells, and normal pluripotent hematopoietic stem cells has been successfully exploited for the extracorporeal purging of simulated autologous remission bone marrow grafts. In this communication, we compare the effects of fractionated vs continuous irradiation upon the MC540-sensitized photoinactivation of L1210 and K562 leukemia cells. Exposure to MC540 (15 micrograms/mL) and fractionated doses of white light inactivated fewer in vitro clonogenic cells than exposure to an equivalent dose of continuous irradiation, provided the irradiation doses were small (8.1-16.2 kJ/m2) and spaced 1-2 h apart. The dye-sensitized photoinactivation of leukemia cells was enhanced when cells were stored at 4 degrees C instead of 37 degrees C between irradiation periods, most likely in part because the cells were unable to repair sublethal photodynamic damages at the lower temperature. These data suggest that cells can recover from sublethal damage inflicted by the plasma membrane-active photosensitizer, MC540.

Animals↗
PubMed1991

Effect of argon laser and Photofrin II on murine neuroblastoma cells.

Laser-induced fluorescence (LIF) of photosensitizers is used to detect cancer. The effect of argon laser light with an average irradiance of 31 mW cm-2 and Photofrin II (Dihematoporphyrin ether, DHE) at concentrations of 1.0 and 5.0 micrograms ml-1 on C1300 murine neuroblastoma cells (MNB, NB41A3) in vitro was investigated. Growth curves and cell viability (trypan blue dye exclusion) were determined at 1, 24, 96, and 144 hr post-irradiation. Light doses of 1.8 and 9.0 J cm-2 combined with 5.0 micrograms DHE ml-1 decreased both cell numbers and viability, immediately and up to 144 hr postirradiation. Argon laser light alone at a fluence of 9.0 J cm-2 caused reversible injury to the cells. This in vitro study shows that both low energy argon laser light and low dose DHE are cytocidal to C1300 MNB cells. LIF promises to aid in the detection and destruction of neuroblastoma. Surgeons should be aware that tissue irreversible damage is likely to occur when performing LIF detection of neuroblastoma. The doses of laser light and of Photofrin II found to be toxic to neuroblastoma cells in culture may provide guidelines for photodynamic therapy ablation of neuroblastoma clinically.

Animals↗
PubMed1988

Comparison of local tumor recurrence following excision with the CO2 laser, Nd:YAG laser, and Argon Beam Coagulator.

This study compares the incidence of local tumor recurrence following primary excision with the CO2 laser, Nd:YAG laser (contact), Argon Beam Coagulator, or electrocautery. One hundred eight Fisher 344 rats with R3230AC mammary tumors (1.6 +/- 0.04 [SD] cm diameter) were used. All animals were randomized into groups of similar tumor size. In groups C and CS, excision was performed with a Sharplan 1060 CO2 laser (TEMoo, 25 W, continuous wave [CW], 0.2-mm spot size). Wounds in group CS were "sterilized" (0.5-mm spot size, 25 W, CW) by gently heating the wound without causing blanching or charring. In group N, a 0.4-mm contact Laser Blade and a Cooper 8000 Nd:YAG laser at 20 W CW was used. In groups SA1 and SA2, tumors were excised with the scalpel, and hemostasis and wound "sterilization" were accomplished with the Bard System 6000 Argon Beam Coagulator (ABC) at 40 W and 4 liters/min argon gas flow in SA1 and 12 liters/min in SA2. In group E, excision was accomplished at 40 W blend mode, 10 W spray mode. In group EA, excision was accomplished at 60 W cutting current, and hemostasis was achieved with the ABC. The animals were examined for evidence of recurrence for 34 days postoperatively. Mortalities were excluded from analysis. The incidence of recurrence was 11/14 (79%) in C, 6/16 (38%) in CS, 10/14 (71%) in SA1, 6/13 (46%) in SA2, 6/15 (40%) in N, 7/10 (70%) in EA, and 3/15 (20%) in E. Group E is statistically different (P less than .01) from groups EA, C, and SA1. Group C was different (P less than .01) from groups E, CS, and N. These results demonstrate an inverse relationship between tumor recurrence and local thermal effects at the surgical site. The ABC did not increase tumor recurrence. Contact YAG surgery was similar to CO2 laser excision and "sterilization." An attempt to study the influence of gas flow and pressure on local tumor recurrence and metastases should be made.

Adenocarcinoma↗
PubMedDate not supplied

Plasmacytoma of the gastrointestinal tract in Korea: higher incidence than in Japan and Epstein-Barr virus association.

As a result of a systematic review of non-Hodgkin's lymphoma of the gastrointestinal tract (GI) at the Yonsei University, Seoul, Korea and the Osaka University, Osaka, Japan, we found an extramedullary plasmacytoma in 5 of a total of 78 cases (6.4%) in Korea and 1 of 136 cases (0.7%) in Osaka, which represents an approximately 9-fold difference in frequency. The presence of the Epstein-Barr virus (EBV) genome was examined in paraffin-embedded specimens from the 5 cases with GI plasmacytoma from Korea together with 17 patients collected by a nationwide study in Japan. There were no clinical findings suggestive of the presence of immunodeficiency in these Korean and Japanese patients. There were no prominent differences in the age distribution or sex ratio between the patients of the two countries. Histologically, the proliferation of mature plasma cells was almost monomorphous with occasional bi- or multinucleated forms. The immunohistochemistry revealed a restricted cytoplasmic expression of immunoglobulin light chain, kappa type in 8 cases and lambda type in 14. A polymerase chain reaction of preserved DNA from 4 Korean and 16 Japanese patients found that only 2, both Korean, were positive for EBV of subtype A. The difference in the frequency of EBV positivity between Korean and Japanese cases was significant (p < 0.05). In situ hybridization revealed positive signals in the nucleus of the tumor cells. IHC revealed that the tumor cells in these two cases were positive for latent membrane protein-1 and EB nuclear antigen-2, showing latent infection of EBV. These findings suggest a close association of EBV and Korean GI plasmacytoma, and might partly explain the remarkable number of cases in this country.

Adolescent↗