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S Qiu

Publications and source records attributed to S Qiu.

At least 19 recordsLinked to original sources
PubMed2006

Calibration of a 220Rn flow-through source.

Two reference methods have been established to calibrate the yield of a self-made 220Rn flow-through source. These reference methods include (a) a small scintillation cell flow-through method and (b) a gamma spectrometry method that takes advantage of an activated charcoal. The methods were validated theoretically and experimentally including intercomparison measurements. It is shown that the source is stable with a relative deviation less than 2.5% over 5 years, when the relative humidity ranged from 50 to 90%, and the temperature from 5 to 38 degrees C. The 220Rn monitor used in these reference methods is calibrated without a 220Rn gas source with determinate yield. On the basis of the calibration of the 220Rn source by the methods mentioned above, the accurate calibration of any 220Rn monitor by the self-made 220Rn source with stable yield is feasible.

Calibration↗
PubMed2002

Age and distance from the surface but not menopause reduce osteocyte density in human cancellous bone.

Previous studies of osteocyte density in human cancellous bone have relied mainly on autopsy samples and have demonstrated an age-related decline in men, but there are insufficient data in women. Using previously obtained transiliac bone biopsies from 94 healthy white women, aged 20-73 years, 38 premenopausal and 56 postmenopausal, we measured osteocytes and lacunae in ten randomly selected areas using 5-microm-thick sections stained with Goldner trichrome. For each subject, the number of osteocytes (Ot.N/B.Ar), empty lacunae (EL.N/B.Ar), and total lacunae (Tt.L.N/B.Ar) per bone area, and the proportion of occupied lacunae (Ot.N/Tt.L.N), were calculated. In 92 cases the measurements were made separately in superficial bone (<25 microm from the surface) and in deep bone (>45 microm from the surface). Mean values and differences between extreme values (DEV) for each variable were computed from the ten measured areas. In addition, confocal microscopic examination was performed on 100 microm sections. We found that Ot.N/B.Ar, Tt.L.N/B.Ar, and Ot.N/Tt.L.N decreased, but EL.N/B.Ar increased significantly with age (p < 0.001). The rates of decline were most rapid initially, falling exponentially with increasing age; the linear regressions for all four variables were significant in premenopausal, but not postmenopausal, women. At all ages, there were significantly more osteocytes in superficial than in deep bone; there was no significant decline with age in superficial bone, but a steeper exponential decline in deep bone than in whole trabeculae. DEV did not change with age for any variable. Confocal images revealed that the morphology of the osteocyte network was heterogeneous in different regions and trabeculae. The trabeculae with lower osteocyte density contained acellular areas, especially in interstitial bone. We conclude: (1) osteocyte density declines with age in women as it does in men; (2) the decline occurs exclusively in deep bone, not in superficial bone, suggesting that it is the age of the bone rather than the age of the subject that is important; (3) the rate of age-related decline falls exponentially with age and is not significant in postmenopausal women alone; (4) except for the differences between superficial and deep bone, the pattern of osteocyte distribution within and between trabeculae was not affected by age or menopause; and (5) the data raise the possibility that one function of remodeling in iliac cancellous bone is to maintain osteocyte viability.

Adult↗
PubMed2002

Relationships between osteocyte density and bone formation rate in human cancellous bone.

Iliac cancellous osteocyte density decreases with age in deep bone but not in superficial bone, most likely because of remodeling. It has been suggested that osteocytes can inhibit bone remodeling. Accordingly, we examined the relationship between osteocyte density and bone formation rate in 92 healthy women. In superficial bone (<25 microm from the surface), we found a weak but significant (p < 0.03) inverse correlation between BFR/BS and Ot. N/B.Ar that was unaffected by menopause and independent of age. A weaker positive relationship with empty lacunar density improved significance. The data appear to suggest a negative feedback loop, but osteocytes explain only 10% of the variance in BFR/BS, and 97% of the variance in osteocyte density is explained by total lacunar density. This measure of initial osteocyte density during bone formation has a high coefficient of variation (20%) indicating large individual differences. We conclude that: (1) our data support the proposal that osteocytes can inhibit bone remodeling; (2) osteocyte density in superficial bone depends mainly on initial osteocyte density during bone formation and is maintained but not regulated by bone remodeling; and (3) the inverse relationship between BFR/BS and osteocyte density may reflect the homeostatic need to maintain calcium exchangeability in the lining cell-osteocyte syncytium.

Adult↗
PubMed2001

The crystal structure of the influenza matrix protein M1 at neutral pH: M1-M1 protein interfaces can rotate in the oligomeric structures of M1.

The influenza matrix protein (M1) forms a protein layer under the viral membrane and is essential for viral stability and integrity. M1 mediates the encapsidation of the viral RNPs into the viral membrane by its membrane and RNP-binding activities. In order to understand the roles of M1-M1 protein interactions in forming the M1 layer, X-ray crystallographic studies of a M1 fragment (1-162) were carried out at neutral pH and compared with an acidic pH structure. At neutral pH the asymmetric unit was a stacked dimer of M1. A long molecular ribbon of neutral stacked dimers was formed by translation as dictated by the P1 space group. The elongated ribbon had a positively charged stripe on one side of the ribbon. A similar M1-M1 stacking interface was also found in the acidic asymmetric unit. However, within the acidic stacked dimer the molecules were not straight, but rotated in relation to each other by slightly changing the M1-M1 stacking interface. The acidic structure possessed an additional M1-M1 twofold interface. Protein docking confirmed that the M1-M1 stacking and M1-M1 twofold interfaces could be used to form a double ribbon of M1 molecules. By iterative repetition of the rotated relationship among the M1 molecules, a helix of M1 was generated. These studies suggest that M1 has the ability to form straight or bent elongated ribbons and helices. These oligomers are consistent with previous electron microscopic studies of M1, which demonstrated that isolated M1 formed elongated and flexible ribbons when isolated from what appeared to be a helical shell of M1 in the influenza virus.

Crystallography, X-Ray↗
PubMed2001

Mesoporous aluminosilicates with ordered hexagonal structure, strong acidity, and extraordinary hydrothermal stability at high temperatures.

Highly ordered hexagonal mesoporous aluminosilicates (MAS-5) with uniform pore sizes have been successfully synthesized from assembly of preformed aluminosilcate precursors with cetyltrimethylammonium bromide (CTAB) surfactant. The aluminosilicate precursors were obtained by heating, at 100--140 degrees C for 2--10 h, aluminasilica gels at the Al(2)O(3)/SiO(2)/TEAOH/H(2)O molar ratios of 1.0/7.0--350/10.0--33.0/500--2000. Mesoporous MAS-5 shows extraordinary stability both in boiling water (over 300 h) and in steam (800 degrees C for 2 h). Temperature-programmed desorption of ammonia shows that the acidic strength of MAS-5 is much higher than that of MCM-41 and is comparable to that of microporous Beta zeolite. In catalytic cracking of 1,3,5-triisopropylbenzene and alkylation of isobutane with butene, MAS-5 exhibits greater catalytic activity and selectivity, as compared with MCM-41 and HZSM-5. The MAS-5 samples were characterized with infrared, UV--Raman, and NMR spectroscopy and numerous other techniques. The results suggest that MAS-5 consists of both mesopores and micropores and that the pore walls of MAS-5 contain primary and secondary structural building units, similar to those of microporous zeolites. Such unique structural features might be responsible for the observed strong acidity and high thermal stability of the mesoporous aluminosilicates with well-ordered hexagonal symmetry.

Journal Article↗
PubMed2001

Preferential production of interferon-gamma by CD4+ T cells expressing the homing receptor integrin alpha4/beta7.

Recent studies indicate that T helper type 1 (Th1) and 2 (Th2) lymphocytes differ in their expression of molecules that control T-cell migration, including adhesion molecules and chemokine receptors. We investigated the relationship between cytokine production and expression of the homing receptor integrin alpha4/beta7 on T cells. We began by analysing cytokine production by human CD4+ CD45RA- memory/effector T cells following brief (4 hr) stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin. alpha4/ beta7high CD4+ T cells were more likely to produce the Th1 cytokine interferon-gamma (IFN-gamma) than were alpha4/beta7- CD4+ T cells in all six subjects studied. In contrast, production of the Th2 cytokine interleukin-4 (IL-4) was similar on alpha4/ beta7high and alpha4/beta7- CD4+ T cells. In addition, we found that human CD4+ CD45RA- T cells that adhered to the alpha4/beta7 ligand mucosal addressin cell adhesion molecule-1 (MAdCAM-1) had a greater capacity to produce IFN-gamma than did non-adherent cells, suggesting that the association between alpha4/beta7 expression and IFN-gamma production has functional significance. These results suggested that primary activation under Th1-promoting conditions might favour expression of alpha4/beta7. We directly examined this possibility, and found that naïve murine CD4+ T cells activated under Th1-promoting conditions expressed higher levels of alpha4/beta7 compared to cells activated under Th2-promoting conditions. The association between alpha4/beta7 expression and IFN-gamma production by CD4+ T cells may help to determine the cytokine balance when MAdCAM-1 is expressed at sites of inflammation in the intestine or elsewhere.

Adult↗
PubMed2000

Study of the assembly of vesicular stomatitis virus N protein: role of the P protein.

To derive structural information about the vesicular stomatitis virus (VSV) nucleocapsid (N) protein, the N protein and the VSV phosphoprotein (P protein) were expressed together in Escherichia coli. The N and P proteins formed soluble protein complexes of various molar ratios when coexpressed. The major N/P protein complex was composed of 10 molecules of the N protein, 5 molecules of the P protein, and an RNA. A soluble N protein-RNA oligomer free of the P protein was isolated from the N/P protein-RNA complex using conditions of lowered pH. The molecular weight of the N protein-RNA oligomer, 513,879, as determined by analytical ultracentrifugation, showed that it was composed of 10 molecules of the N protein and an RNA of approximately 90 nucleotides. The N protein-RNA oligomer had the appearance of a disk with outer diameter, inner diameter, and thickness of 148 +/- 10 A, 78 +/- 9 A, and 83 +/- 8 A, respectively, as determined by electron microscopy. RNA in the complexes was protected from RNase digestion and was stable at pH 11. This verified that N/P protein complexes expressed in E. coli were competent for encapsidation. In addition to coexpression with the full-length P protein, the N protein was expressed with the C-terminal 72 amino acids of the P protein. This portion of the P protein was sufficient for binding to the N protein, maintaining it in a soluble state, and for assembly of N protein-RNA oligomers. With the results provided in this report, we propose a model for the assembly of an N/P protein-RNA oligomer.

Cloning, Molecular↗
PubMed2000

Proteolytic processing of the astrovirus capsid.

To further characterize the nature of proteolytic processing of the astrovirus capsid, we infected Caco-2 cells with a high multiplicity of astrovirus without trypsin in the presence of 5 to 10% fetal calf serum. These infections were characterized by pulse-chase labeling with [35S]Smethionine, electron microscopy, gel electrophoresis of purified viral particles, and analysis of infectivity of such particles with and without added trypsin. Pulse-chase experiments showed that the astrovirus capsid protein was initially translated as an approximately 87-kDa protein. The 87-kDa capsid protein was rapidly converted intracellularly to a 79-kDa form which was found in smaller amounts in the cell supernatant. Purification by differential centrifugation yielded particles that appeared quite similar to trypsin-grown astrovirus particles by negatively stained electron microscopy. These particles were antigenically distinct from trypsin-treated virions as demonstrated by their various reactions with monoclonal antibodies in a solid-phase immunoassay. The purified trypsin-free particles were mainly composed of the 79-kDa capsid protein which was found to have an amino terminus at residue 71 of the entire open reading frame 2 (ORF2) product. The cleavage site was identified in a highly conserved region of the astrovirus ORF2 product. These trypsin-free particles were minimally infectious in cultured Caco-2 cells but became highly infectious (10(5)-fold increase) after trypsin but not chymotrypsin treatment. This trypsin-enhanced infectivity correlated with conversion of the 79-kDa capsid protein to three smaller peptides of approximately 34, 29, and 26 kDa.

Antigens, Viral↗
PubMed2000

[A preliminary study on the activation of superoxide dismutase by Tiopronin in patients with chronic hepatitis B].

OBJECTIVE: To observe the clearance effect of Tiopronin on oxygen free radicals in chronic hepatitis B patients. METHODS: The ranthine oxidase assay was used to detect superoxide dismutase (SOD) in 80 chronic hepatitis B patients, the ALT, TBil, TP and AIG ratio of the patients were also tested. The 80 chronic hepatitis B patients were divided into two groups, the control group was treated with routine liver protective and jaundice regressing drugs while the treated group was additionally administered with Tiopromin besides the routine treatment. RESULTS: In two groups of patients with similar ages and sexes, there showed no differences in levels of SOD, ALT, TBil, TP and ALB before treatment, as the SOD in treated group and control group were 106.57 (40.68 NU/ml and 105.18(44.59 NU/ml respectively, while the normal value for SOD in 16 normal persons was 165.9(23.36 NU/ml. After treatment, there were significant differences (P< 0.01) in SOD, ALT, TBil and ALB levels which showed SOD 187.93(35.24 NU/ml, ALT 38.41(22.22 U/L, TBil 23.15(12.46 micromol/L, ALB 43.28 (4.21 g/L in the treated group and SOD 157.96(47.29 NU/ml, ALT 68.52(34.19 U/L, TBil 30.38(21.80 micromol/L and ALB 40.36(5.19 g/L in the control group. CONCLUSIONS: There showed a good therapeutic effect of Tiopronin on the clearance of oxygen free radicals in chronic hepatitis B patients and also it can improve the liver function.

Adult↗
PubMed2000

CT via percutaneous splenoportography: experiment and application.

OBJECTIVE: To introduce computed tomography via percutaneous splenoportography (CTSP), a new method for determining hepatic diseases. METHODS: Ten hybrid dogs and 31 patients with primary hepatic cancer (PHC) were included in the study. Each dog was examined by CT, computed tomography via arterial portography (CTAP), and CTSP to compare the enhanced density of the liver. The 31 patients were examined by CTSP and the appearance of PHC was compared with their pathological results to evaluate the diagnostic significance of CTSP. RESULTS: The animal experiment showed that both CTAP and CTSP could obviously enhance the density of the liver (P < 0.01), but no significant difference was observed in the enhanced densities between the two methods (P > 0.05). On the CTSP images of the 31 patients, the density of the livers was increased to 168-192 Hu, whereas the density of the cancers was as low as that on the images of CT scans (< 58 Hu). The CTSP findings were consistent with the surgical ones from space occupying lesions. The diagnostic value of CTSP was obviously superior to that of general enhanced CT. However, it was difficult for CTSP to show nodules less than 1 cm in size located on the surface of the liver or the hepatic portal zone. CONCLUSIONS: Like CTAP, CTSP is also a sensitive method for showing occupant in the liver. But the equipments and the procedures are simpler for CTSP than for CTAP. CTSP is an alternative procedure in clinical practice.

Animals↗
PubMed2000

[Treatment of non iatrogenic injury of retrohepatic inferior vena cava].

OBJECTIVE: To study a repair method for injured retrohepatic inferior vena cava (IVC) associated with liver trauma. METHODS: Laceration of IVC was sutured bloodlessly after the injured retrohepatic IVC was occluded by compression combined with occlusion of the first hepatic hilus. RESULTS: From April 1996 to January 1999, the injured IVC was successfully repaired in 6 patients. The length of laceration was 2.9 cm (1.5 - 4 cm). The occlusion time was 9.2 min (6 - 15 min) for the IVC and 20.5 min (15 - 29 min) for the first hepatic hilus, respectively. All patients recovered uneventfully, and the IVC was patency without stricture as showed by B-mode ultrasonography and CT. CONCLUSION: The injured retrohepatic IVC can be repaired by direct compression when the laceration of the IVC is caused by liver trauma.

Adolescent↗
PubMed2000

[Use of Hopkins rod-lens coupled with grasping forceps sheaths for extraction of tracheobronchial foreign bodies].

OBJECTIVE: To study the clinical application of Hopkins rod-lens coupled with gasping forceps sheaths in the extraction of tracheobronchial foreign bodies. METHODS: Sixty-two patients with tracheobronchial foreign bodies were operated on with Hopkins rod-lens coupled with grasping forceps sheaths under direct telescopic view or TV watching. High frequency jet ventilation was used and BPs ECGs SaO2 were monitored in all cases. RESULTS: Sixty-two patients were all successfully operated on. The extraction was primarily successful in 90% of the cases; and secondarily successful in 7% of the cases. No death and serious complication occurred. CONCLUSION: Compared with conventional bronchoscopic foreign body extraction, this new instrument and technique make it possible for the operator to clamp and extract foreign body under direct telescopic view or TV watching. It has increased the accuracy and safety of bronchoscopic extraction of tracheobronchial foreign bodies.

Adolescent↗
PubMed1999

Preparation of Cu Nanoparticles from Water-in-Oil Microemulsions.

Spherical Cu nanoparticles were synthesized in sodium dodecyl sulfate (SDS)/isopentanol/cyclohexane/water microemulsions with sodium borohydride as a reducing agent. Nanoparticles formed in microemulsions were characterized by transmission electron microscopy (TEM), x-ray diffractometry (XRD), and small-angle X-ray scattering (SAXS). The size and polydisperity of particles were greatly affected by the mole ratio of water to surfactant (w) and the concentration of precursor salt. The ideal size and monodispersity of nanoparticles can be obtained at the smaller w value and lower concentration of Cu(2+) solution. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Surgical treatment of hepatocellular carcinoma and related basic research with special reference to recurrence and metastasis.

OBJECTIVE: To summarize the progress of surgical treatment of hepatocellular carcinoma (HCC) and related basic research at the Liver Cancer Institute of Shanghai Medical University in the recent years, with special reference to recurrence and metastasis. METHODS: Published and unpublished update clinical and experimental data in the above-mentioned areas are summarized. RESULTS: Surgical resection has played an important role in improving prognosis of HCC, the 5-year survival were 63.4% for small HCC resection (n = 806), 39.6% for large HCC resection (n = 1061), 64.7% for cytoreduction (using hepatic artery cannulation and ligation) and sequential resection of initially unresectable HCC (n = 93), 56.0% for cytoreduction using transcatheter arterial chemoembolization (TACE) and followed by resection (n = 65), and 22.4% for hepatic resection with removal of tumor thrombi in portal vein (n = 103). Unfortunately, the 5-year recurrent rate after curative resection of HCC was up to 61.5%, which was mainly a result of intrahepatic "metastasis" and multicentric origin of HCC. Clinically, re-resection of subclinical recurrence yielded 56% of 5-year survival (n = 202); prevention of recurrence by transcatheter arterial chemoembolization (TACE) + Interferon, or LAK/IL-2 therapy have decreased 3-year recurrent rate from 33% to 11%-18%. In experimental aspect, metastatic human HCC model in nude mice (LCI-D20) and HCC cell line with metastatic potential (MHCC97) have been established; studies on HCC invasiveness in the molecular level revealed similar results that reported in other solid cancers, and small HCC showed slightly better biological characteristics as compared with large HCC; microvessel density (MVD) that reflecting angiogenesis adversely correlated with 5-year survival of small HCC; experimental interventions using antisense H-ras, bispecific antibody, BB94, as well as anti-angiogenic agents (TNP470, suramin, CAI, heparin, antisense VEGF, etc.) have been demonstrated to inhibit tumor growth and lung metastasis in nude mice model. CONCLUSIONS: Recurrence and metastasis are the major obstacle to further improve prognosis of HCC, studies should be conducted both in clinical and experimental aspects, "HCC invasiveness" will be the major target to be studied, particularly in the molecular level, and anti-angiogenesis will be one of the important approach.

Angiogenesis Inhibitors↗
PubMed1999

[Hepatic resection with removal of tumor thrombi for hepatocellular carcinoma with tumor thrombi in portal vein and curative analysis].

OBJECTIVE: To study the therapeutic effects of surgical treatment for hepatocellular carcinoma (HCC) with tumor thrombi in the main trunk or the first branch of the portal vein (PVTT) and factors affecting prognosis. METHODS: 111 HCC patients with PVTT underwent hepatic resection with removal of tumor thrombi in the first left or the right branch of the portal vein or removal of tumor thrombi by direct opening of the main trunk of the portal vein. Hepatic artery infusion and/or portal vein infusion were performed after hepatic resection with removal of tumor thrombi for HCC with PVTT in 22 of the patients. Among 111 patients, 32 received postoperative transhepatic arterial chemoembolization and/or portal vein chemotherapy. Conservative treatment and surgical exploration or hepatic artery ligation (HAL) and infusion (HAI) and/or portal vein infusion (PVI) were performed in other 14 and 20 HCC patients with PVTT, respectively. RESULTS: The 1-, 2-, 3-, 4- and 5- year survival rates were 61.7%, 36.2%, 32.3%, 24.4% and 22.4% in the resected group, respectively, whereas 14 HCC patients with PVTT treated conservatively died in three months and the 1-, 2- year survival rates were 6.0% and 0 in the 20 patients with surgical exploration or HAL and HAI and/or PVI respectively. CONCLUSIONS: Hepatic resection with removal of tumor thrombi for HCC with PVTT should be encouraged for the prolongation of life span and quality of life.

Adult↗
PubMed1999

[Pharmacological comparison between volatile oil and water extract].

OBJECTIVE: To compare the pharmacological differences between volatile oil and water extract in eight aromatic drugs for resolving dampness. METHOD: Volatile oil and water extract of eight commonly used aromatic drugs for resolving dampness were ig administered to rats respectively, and the effects of volatile oil and water extract on the secretion of gastric juice, volume of gastric mucous blood flow and activity of SOD in gastric mucous membrane were studied. RESULT: It was shown that the effects of aromatic volatile oil in eight drugs on the indexes mentioned above were generally equal or similar to those of water extract, and it was obvious that the volatile oil in some high oil content drugs such as Amonum cardamomum L(Baidoukou), Alpinia katsumadai Hagata (Caodoukou), Amomum villosum Lour (Saren), and Amomum tsao-ko Crevost et Lem (Caogou) had better effects on the secretion of gastric juice and volume of gastric mucous blood flow that those of water extract. CONCLUSION: It has been pharmacologically proved that in using aromatic drugs for resolving dampness, the loss of aromatic (volatile) components should be avoided.

Animals↗