Objective To optimize the enamel electron paramagnetic resonance (EPR) spectral processing by using the EPR spectral simulation method to improve the accuracy of enamel EPR dosimetry and reduce artificial error.Methods The multi-component superimposed EPR powder spectral simulation software was developed to simulate EPR spectrum models of the background signal(BS) and the radiation- induced signal (RS) of irradiated enamel respectively.RS was extracted from the multi-component superimposed spectrum of irradiated enamel and its amplitude was calculated.The dose-response curve was then established for calculating the doses of a group of enamel samples.The result of estimated dose was compared with that calculated by traditional method.Results BS was simulated as a powder spectrum of gaussian line shape with the following spectrum parameters:g =2.00 35 and Hpp =0.65 - 1.1 mT,RS signal was also simulated as a powder spectrum but with axi-symmetric spectrum characteristics.The spectrum parameters of RS were:g(1) =2.0018,g (11) =1.996 5,Hpp =0.335 - 0.4 mT.The amplitude of RS had a linear response to radiation dose with the regression equation as y =240.74x + 76 724 ( R2 =0.9947 ).The expectation of relative error of dose estimation was 0.13.Conclusions EPR simulation method has improved somehow the accuracy and reliability of enamel EPR dose estimation.

Objective To evaluate the quality of the portal images acquired by computed radiography(CR)system and conventional screen-film system,respectively.Methods imaging plates (IP)and X-ray films of a home-devised lead phantom with a leakage of 6.45% were acquired,and modulation transfer function(MTF)curves of the both images were measured using edge method.Portal images of 40 nasopharyngeal cancer patients were acquired by IP and screen-film system respectively.Two doctors with similar experience evaluated the damage degree of petrosa] bone,the receiver operating characteristic(ROC)curve of CR images and general images were drawn according to two doctors evaluation results.Results The identification frequency of CR system and screen-film system were 1.159 and 0.806 Lp/mm respectively.For doctor one,the area under ROC curve of CR images and general images were 0.802 and 0.742 respectively.For doctor two,the area under ROC curve of CR images and general images were 0.751 and 0.600 respectively.The MTF curve and ROC curve of CR are both better than those of screen-film system.Conclusion The image quality of CR portal imaging is much better than that of screen-film system.The utility of CR in linear accelerator for portal imaging is promising in clinic.

OBJECTIVETo study the features of micro satellite alterations and their association with clinicopathological characteristics of hepatocellular carcinoma (HCC).

METHODSTen high-polymorphic micro satellite markers on chromosome 4 were selected to be detected for loss of heterozygosity (LOH), micro satellite instability (MSI) and allelic imbalance (AI) in 56 HCC using PCR-simple sequence length polymorphism (PCR-SSLP) analysis.

RESULTSLOH was found in 40 of 56 HCC (71.4%) on at least 1 locus, the top two loci were D4S426 (61%), D4S1534 (53.7%). LOH on D4S406 was significantly higher in cases with positive serum HBsAg than in those with negative HBsAg. Similarly, LOH on D4S1538 occurred more frequently in patients with HBsAg negative than those with HBsAg positive [76.9% (20/26) vs 12.5% (2/16), chi2=13.999, P<0.01]. LOH on D4S426, D4S1615 and D4S165 were more frequent in poorly or moderately differentiated HCC than in well-differentiated HCC [76.7%(23/30) vs 18.2%(2/11), chi2=9.242, P<0.01; 53.8% (14/26) vs 16.7% (2/12), P<0.05; 60.7% (17/28) vs 18.2% (2/11), P<0.01]. LOH on loci D4S2921 was more frequently detected in tumors with intrahepatic metastasis than in those without [63.6% (21/33) vs 18.2% (2/11), chi2=5.132, P<0.01]. MSI was found in 8.9% (5/56) cases. AI was found in 26.8% (15/56) of all cases examined.

CONCLUSIONFrequent micro satellite alterations on chromosome 4 were existed in HCC. LOH, which represents tumor suppressor gene pathway, plays a more important role in hepatocarcinogenesis of HCC; MSI, representing mismatch repair gene pathway, arranges as the next.

Adult ; Aged ; Carcinoma, Hepatocellular ; genetics ; Chromosomes, Human, Pair 4 ; Female ; Humans ; Liver Neoplasms ; genetics ; Loss of Heterozygosity ; Male ; Microsatellite Repeats ; Middle Aged

OBJECTIVETo evaluate the possible association of the MTHFR C677T polymorphism with genetic susceptibility to hepatocellular carcinoma (HCC) in a Chinese population.

METHODSFive hundred and eight HCC cases and 543 controls were studied. The MTHFR genotypes were determined using a PCR-based restriction fragment length polymorphism (RFLP) method. Odds ratios (ORs) for HCC and 95% confidence intervals (CIs) from unconditional logistic regression models were used to evaluate relative risks. Potential HCC risk factors were included in the logistic regression models as covariates in the multivariate analyses on genotypes and HCC risks.

RESULTSNo overall significant difference in genotype distribution was found when comparing all HCC cases to controls (P = 0.258). However, a significantly increased risk of HCC was observed among T/T homozygotes (adjusted OR = 1.66, 95% CI = 1.08-2.54, P<0.05) compared to C-allele carriers (CC or CT). When stratified with sex, this trend was more prominent in females, but not in males. Females who were homozygous (T/T) for the C677T polymorphism were at a 2.64-fold (95% CI = 1.19-5.88, P<0.05) increased risk of developing HCC when compared to C-allele carriers. However in males, T/T homozygotes had a similar risk with C-allele carriers.

CONCLUSIONThe MTHFR C677T polymorphism may be associated with a higher HCC risk in females, but not in males in this population.

Aged ; Carcinoma, Hepatocellular ; genetics ; Female ; Genetic Predisposition to Disease ; Humans ; Liver Neoplasms ; genetics ; Logistic Models ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Middle Aged ; Polymorphism, Genetic

OBJECTIVETo study the features of microsatellite alterations and their association with clinicopathological characteristics of hepatocellular carcinoma (HCC).

METHODSTen high-polymorphic microsatellite markers on chromosome 8 were selected to detect the loss of heterozygosity (LOH), microsatellite instability (MSI) and allelic imbalance (AI) in 56 HCCs using automatic capillary array electrophoresis DNA analysis system.

RESULTSLOH was found in 37 of 56 HCCs (66.1%) on at least 10 locus. The three most frequently altered loci were D8S261 (53.5%, 23/43), D8S1721 (52.5%, 21/40) and D8S1771 (52.5%, 21/40). LOH on D8S277 was significantly higher in cases with positive serum HBsAg than in those with negative HBsAg (P < 0.01). Similarly, LOH on D8S261, D8S298 and D8S1733 occurred more frequently in patients with negative HBsAg than those with positive HBsAg (P < 0.01). LOH on D8S298 and D8S1771 were more frequent in tumors larger than 3 cm in size (P < 0.05 and P < 0.01 respectively). LOH frequencies of D8S1721 were significantly higher in cases with absent or partially encapsulated tumor than in those with intact tumor capsule (P < 0.05). LOH on D8S298 and D8S1771 were more frequently detected in tumors with intrahepatic metastasis than those without (P < 0.01). MSI was found in 12.5% (7/56) cases. AI was found in 19.6% (11/56) of all cases examined.

CONCLUSIONSMicrosatellite alterations on chromosome 8 were frequent in HCC. LOH, possibly representing alterations of the tumor suppressor pathway, may play an important role in hepatocarcinogenesis. MSI, reflecting a dysfunction of the mismatch repair pathway, may also contribute to this process, but in a less significant way. LOH at some particular loci is associated with certain clinicopathological parameters of human HCC.

Adult ; Aged ; Allelic Imbalance ; Carcinoma, Hepatocellular ; genetics ; pathology ; Chromosomes, Human, Pair 8 ; Female ; Humans ; Liver ; pathology ; Liver Neoplasms ; genetics ; pathology ; Loss of Heterozygosity ; Male ; Microsatellite Repeats ; Middle Aged

OBJECTIVETo scrutinize the immunohistochemical spectrum to differentiate hepatocellular carcinoma (HCC) from intrahepatic cholangiocarcinoma (ICC) and metastatic adenocarcinoma (MAC) in the liver.

METHODSSeven antibodies including AFP, Hep Par 1, CK18, CK19, CA19-9, CD34 and pCEA were immunohistochemically stained in resected specimens of 300 HCC, 35 ICC and 30 MAC. The specificity and sensitivity of the antibodies were evaluated by comprehensive capability score (CCS), with only those with CCS > or = 8 considered as having highly diagnostic value.

RESULTSAntibodies CCS > or = 8 were observed as Hep Par 1 and CD34 in HCC, and CK19 in ICC, but none in MAC. For HCC, CCS of Hep Par 1 was higher than that of AFP (9 vs. 7) with 83.7% in sensitivity and 96.7% in specificity.

CONCLUSIONFor HCC, Hep Par 1 and CD34 can be used as the first line antibodies, AFP and pCEA as the second line ones. CK19 is the first line antibody for ICC, and CA19-9 as the second. Hep Par 1, CD34 and CK19 are definitely helpful for the routine immunohistochemical stain to differentiate HCC from ICC and MAC.

Adenocarcinoma ; chemistry ; Antibodies ; immunology ; Carcinoma, Hepatocellular ; chemistry ; Cholangiocarcinoma ; chemistry ; Humans ; Immunohistochemistry ; Liver Neoplasms ; chemistry ; Tumor Cells, Cultured

A set of L-band electron spin resonance imaging (ESRI) equipment suitable for biological species was developed and an ESRI experiment model for viable skin samples was established. The mechanic process of nitroxide free radical TEMPO (2,2, 6, 6-tetramethyl-1-piperidinyloxy) penetrating through skin sample and the spin density distribution of TEMPO after it interacted with skin sample were detected by the developed ESRI method. Skin samples were extracted from mice back. The experimental samples were prepared by cutting the skin pieces into square shape of 2 x 2 cm2 and then the samples were divided into three groups by treating them with three different methods: Method A, simple treatment by simply cutting the hair; method B, 8% Na2S depilation treatment for 10 min; method C, 8% Na2S depilation and then 5% pancreatic digestion treatment for 2 hours. The liposoluble solvent DMSO (dimethyl sulfoxide) and distilled water were used as two kinds of solvent for the TEMPO liquor. The results indicated that the skin-penetration properties of TEMPO were significantly different among samples treated with different methods and the surface cornifin of skin offered remarkable resistance to TEMPO. The TEMPO liquor of water could hardly penetrate through skins, whereas about 20%-30% of the original TEMPO compounds that solved in liposoluble solvent DMSO could penetrate through the skin sample treated with method C after 16 hours of interaction. Furthermore, the penetration rate of TEMPO through the skin tissue was a strong time dependent process. The preliminary application results suggested that ESRI technique could provide an effective and applicable method for dynamically researching skin-penetration properties of some special kinds of materials such as paramagnetic compounds.
Animals ; Cyclic N-Oxides ; pharmacokinetics ; Dimethyl Sulfoxide ; chemistry ; Electron Spin Resonance Spectroscopy ; methods ; Free Radical Scavengers ; pharmacokinetics ; Mice ; Piperidines ; pharmacokinetics ; Skin Absorption ; physiology ; Skin Physiological Phenomena ; drug effects ; Spin Labels

OBJECTIVETo study the effects of intense electromagnetic pulse(EMP) on the biological effects of mitochondrial membrane.

METHODRat liver mitochondrial suspension was exposed to EMP at 60 kV/m level. The changes of membrane lipid fluidity and membrane protein mobility were detected by ESR and spin label technique. Malondialdehyde(MDA) was detected by spectrophotometer.

RESULTSThe mobility of membrane protein decreased significantly(P < 0.05). Correlation time (tau c) of control group was (0.501 +/- 0.077) x 10(-9)s, and tau c of EMP group was (0.594 +/- 0.049) x 10(-9)s, indicating that the mobility of protein was restricted. The fluidity of mitochondrial membrane increased significantly(P < 0.05) at the same time. Order parameter(S) of mitochondrial membrane lipid in control group was 0.63 +/- 0.01, while S of EMP group was 0.61 +/- 0.01(P < 0.05). MDA decreased significantly.

CONCLUSIONThe mobility and lipid peroxidation of mitochondrial membrane may be disturbed after EMP exposure.

Animals ; Electromagnetic Phenomena ; Lipid Peroxidation ; radiation effects ; Membrane Fluidity ; radiation effects ; Mitochondria, Liver ; metabolism ; radiation effects ; Mitochondrial Membranes ; metabolism ; radiation effects ; Rats

OBJECTIVE: To investigate the optimal doses of X-ray irradiation and plasmid injection in the anti-tumor effect of the pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy in vivo. METHODS: We observed the anti-tumor effect of the pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy with different doses of X-ray irradiation (2, 10, 20 Gy) and plasmid injection (10, 20, 30 microg) in nude mice with JF-305 pancreatic carcinoma, and detected the expression of p16 in tumor by RT-PCR. RESULTS: The tumor growth rate of the nude mice irradiated locally with 20 Gy X-rays after the plasmid injection was significantly lower (P < 0.05 ) than that of the nude mice irradiated locally with 2 Gy or 10 Gy X-ray 3 days after the irradiation. The tumor growth rate of the nude mice injected locally with 20 microg or 30 microg plasmid was significantly lower (P <0.05 ) than that of the nude mice injected locally with 10 microg plasmid. Both pcDNA3. 1-Egr. 1p-p16 group and pcDNA3. 1-Egr. 1p-p16 +20 Gy group had p16 mRNA expression, but the mRNA level of pcDNA3. 1-Egr. 1p-p16 +20 Gy group was higher than that of pcD- NA3. 1-Egr. 1p-p16 group. CONCLUSION In the pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy in vivo the optimal dose of X-ray irradiation was 20 Gy and the optimal dose of plasmid injection was 20 microg. The anti-tumor effect of pcDNA3. 1-Egr. 1p-p16 combined with radiotherapy is better than that of radiotherapy or gene therapy alone, which may be related with the enhanced p16 expression in tumor after the irradiation.
Animals ; Combined Modality Therapy ; DNA ; genetics ; Early Growth Response Protein 1 ; genetics ; Female ; Genes, p16 ; Genetic Therapy ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Transplantation ; Pancreatic Neoplasms ; radiotherapy ; therapy ; Recombinant Proteins ; metabolism