OBJECTIVETo assess DNA repair capacity of human lymphocytes with comet assay.

METHODSFresh lymphocytes form twelve 26-year old donors (6 males, 6 females) were exposed to ultraviolet C (UVC, 254 nm) at the dose rate of 1.5 J/m(2). The lymphocytes of each donor were divided into three parts: UVC group, UVC + aphidicolin (APC) group, UVC + novobiocin (NOV) group. DNA single strand breaks were detected with comet assay in UVC-irradiated cells and unirradiated cells incubated for 30, 60, 90, 120, 180 and 240 min. DNA repair rate (DRR) was calculated and served as an indicator of DNA repair capacity.

RESULTSThe maximum average comet tail length (MTL) in three groups appeared 90 min after UVC exposure. The DRR range of UVC group was 81.84% (62.84% - 98.71%); There was no significant difference in DRR between males and females (P > 0.05). However, the average DRRs of UVC + NOV group and UVC + APC group (52.98% and 39.57% respectively) were significantly lower than that of UVC group (P < 0.01).

CONCLUSIONComet assay is a rapid and simple screening test to assess DNA repair capacity. DRR, as an indicator, may express the individual DNA repair capacity.

Aphidicolin ; pharmacology ; Comet Assay ; methods ; DNA ; drug effects ; genetics ; radiation effects ; DNA Repair ; Enzyme Inhibitors ; pharmacology ; Female ; Humans ; Lymphocytes ; drug effects ; metabolism ; radiation effects ; Male ; Novobiocin ; pharmacology ; Ultraviolet Rays

OBJECTIVETo determine the interaction between 2450-MHz microwaves (MW) radiation and mitomycin C (MMC).

METHODSThe synergistic genotoxic effects of low-intensity 2450-MHz microwave and MMC on human lymphocytes were studied using single cell gel electrophoresis (SCGE) assay (comet assay) and cytokinesis-blocked micronucleus (CBMN) test in vitro. The whole blood cells from a male donor and a female donor were either only exposed to 2450-MHz microwaves (5.0 mW/cm2) for 2 h or only exposed to MMC (0.0125 microgram/mL, 0.025 microgram/mL and 0.1 microgram/mL) for 24 h; and the samples were exposed to MMC for 24 h after exposure to MW for 2 h.

RESULTSIn the comet assay, the comet lengths (29.1 microns and 25.9 microns) of MW were not significantly longer than those (26.3 microns and 24.1 microns) of controls (P > 0.05). The comet lengths (57.4 microns, 68.9 microns, 91.4 microns, 150.6 microns, 71.7 microns, 100.1 microns, 145.1 microns) of 4 MMC groups were significantly longer than those of controls (P < 0.01). The comet lengths (59.1 microns, 92.3 microns, 124.5 microns, 182.7 microns and 57.4 microns, 85.5 microns, 137.5 microns, 178.3 microns) of 4 MW plus MMC groups were significantly longer than those of controls too (P < 0.01). The comet lengths of MW plus MMC groups were significantly longer than those of the corresponding MMC doses (P < 0.05 or P < 0.01) when the doses of MMC were > or = 0.025 microgram/mL. In the CBMN, the micronucleated cell (MNC) rates of MW were 5@1000 and 6@1000, which showed no difference compared with those (4@1000 and 4@1000) of controls (P > 0.05). The MNC rates of 4 MMC groups were 8@1000, 9@1000, 14@1000, 23@1000 and 8@1000, 8@1000, 16@1000, 30@1000 respectively. When the doses of MMC were > or = 0.05 microgram/mL, MNC rates of MMC were higher than those of controls (P < 0.05). MNC rates of 4 MW plus MMC groups were 12@1000, 13@1000, 20@1000, 32@1000 and 8@1000, 9@1000, 23@1000, 40@1000. When the doses of MMC were > or = 0.05 microgram/mL, MNC rates of MW plus MMC groups were much higher than those of controls (P < 0.01). MNC rates of 4 MW plus MMC groups were not significantly higher than those of the corresponding MMC doses.

CONCLUSIONThe low-intensity 2450-MHz microwave radiation can not induce DNA and chromosome damage, but can increase DNA damage effect induced by MMC in comet assay.

Antibiotics, Antineoplastic ; adverse effects ; Cell Culture Techniques ; Chromosome Aberrations ; chemically induced ; Comet Assay ; DNA Damage ; Female ; Humans ; Lymphocytes ; Male ; Micronucleus Tests ; Microwaves ; adverse effects ; Mitomycin ; adverse effects ; Mutagenicity Tests

The release behavior of single pellet was investigated by LC/MS/MS method with tamsulosin hydrochloride (TSH) as the model drug of the research and then the pellets were divided into four groups according to the drug loading. Comparison of dissolution profiles of each group and capsule were performed using f1 and f2 factor methods to study the difference and similarity. The release profiles of single pellet, each group and capsule were analyzed using principle component analysis (PCA). The particle system was built through Matlab to get the target release profile. The result of this research demonstrated the release behavior of single pellet correlated well with the drug loading. While the dissolution profile of capsule as a reference, the similarity factor of dissolution profiles of the lower drug loading groups were 62.2, 67.1, 53.9, respectively and, 43.3 for highest drug loading group. The particle systems with different pellet distribution and same release profiles were built through release behavior of single pellet. It is of significance to investigate the release behavior of single pellets for studying the release regularity of multiple-unit drug delivery system.
Capsules ; Chemistry, Pharmaceutical ; Chromatography, Liquid ; Delayed-Action Preparations ; Drug Delivery Systems ; Drug Liberation ; Principal Component Analysis ; Sulfonamides ; administration & dosage ; chemistry ; Tandem Mass Spectrometry ; Technology, Pharmaceutical

A sensitive, rapid and specific liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method for quantification of gabapentin in human plasma has been developed. After a single plasma protein precipitation with methanol, gabapentin and metformin (internal standard) were chromatographed on a Inertsil ODS-3 column (50 mm x 2.1 mm ID, 3 microm) with mobile phase consisting of methanol-0.2% formic acid aqueous solution (80:20, v/v) at a flow-rate of 0.2 mL x min(-1). Electrospray ionization (ESI) source was applied and operated in the positive ion mode. Multiple reaction monitoring (MRM) mode with the transitions of m/z 172 --> m/z 154 and m/z 130 --> m/z 71 were used to quantify gabapentin and metformin, respectively. The run time was 2.2 min. The linear calibration curve was obtained in the concentration range of 40.8-8.16x10(3) ng x mL(-1). The lower limit of quantification was 40.8 ng x mL(-1). The intra- and inter-day precision (RSD) was less than 12%, and the accuracy (RE) was within +/-6.4% calculated from quality control (QC) samples. The method was used to determine the concentration of gabapentin in human plasma after a single oral administration of 600 mg gabapentin capsule to 20 healthy male Chinese volunteers. The method was proved to be selective, sensitive, rapid and suitable for pharmacokinetic study of gabapentin in human plasma.
Administration, Oral ; Amines ; administration & dosage ; blood ; pharmacokinetics ; Anticonvulsants ; administration & dosage ; blood ; pharmacokinetics ; Area Under Curve ; Chromatography, High Pressure Liquid ; Cyclohexanecarboxylic Acids ; administration & dosage ; blood ; pharmacokinetics ; Humans ; Male ; Spectrometry, Mass, Electrospray Ionization ; Tandem Mass Spectrometry ; gamma-Aminobutyric Acid ; administration & dosage ; blood ; pharmacokinetics

OBJECTIVETo study the combined damage-effects of low-intensity 2,450 MHz microwave (MW) with three chemical mutagens on human lymphocyte DNA.

METHODSDNA damage of lymphocytes exposed to microwave and(or) with chemical mutagens were observed at different incubation time (0 h or 21 h) with comet assay in vitro. Three combination-exposure ways of MW with chemicals were used: MW irradiation before chemical exposures, simultaneously exposed to MW and chemicals and MW irradiation after chemical exposures. The three chemical mutagens were mitomycin C (MMC, DNA crosslinker), bleomycin (BLM, radiometric agent), methyl methanesulfonate (MMS, alkylating agent). The exposure time of MW and chemical mutagens were 2 h and 3 h respectively.

RESULTSThe differences of comet tail length between MW group and control group were not significant when lymphocytes were incubated for 0 h or 21 h (P > 0.05). However, when lymphocytes were incubated for 21 h with 30.00 micro mol/L of MMC, the comet tail lengths of MW + MMC group, MW-MMC group and MMC + MW group were (18.00 +/- 5.96), (21.79 +/- 11.47) and (22.32 +/- 8.10) micro m respectively; while with 3.00 micro mol/L of MMC, the comet tail lengths were (8.99 +/- 3.75), (12.40 +/- 5.35) and (14.00 +/- 5.38) micro m respectively, which were significantly higher than those of corresponding MMC groups [(9.42 +/- 3.34) and (6.50 +/- 2.89) micro m, P < 0.01 or P < 0.05]. The DNA damage of MW plus BLM groups and MW plus MMS groups were not significantly different from the corresponding BLM and MMS groups (P < 0.05).

CONCLUSION2 450 MHz MW (5 mW/cm(2)) did not induce DNA damage directly, but could enhance the DNA damage effects induced by MMC. The synergistic effects of 2 450 MHz MW with BLM and MMS were not obvious.

Bleomycin ; pharmacology ; Comet Assay ; DNA ; drug effects ; genetics ; radiation effects ; DNA Damage ; Humans ; Lymphocytes ; drug effects ; metabolism ; radiation effects ; Methyl Methanesulfonate ; pharmacology ; Microwaves ; adverse effects ; Mitomycin ; pharmacology ; Mutagens ; pharmacology ; Time Factors

OBJECTIVETo explore the secular trend in incidence and mortality rate of gastric cancer in Tianjin and to provide evidence and reference for making prevention and control strategy for gastric cancer.

METHODSData derived from Tianjin cancer registry system were analyzed by descriptive epidemiological method and Joinpoint model. A total of 17990 gastric cancer cases reported in Tianjin from 1981 to 2002, including 12755 males and 5235 females were studied.

RESULTSThe annual percent change (APC) of crude incidence rate for males and females was -0.92% (Z = -3.85, P = 0.001) and -0.79% (Z = -2.67, P = 0.015), while the APC of standard incidence rate was -3.55% (Z = -13.52, P = 0.000) and -3.47% (Z = -12.85, P = 0.000). There was a descending trend of incidence rate in males and females above 45-years-old, however, in male under 45 years it showed an increased trend and in females it kept stable. The APC of crude mortality rate was -1.66% ( Z = -5.79, P = 0.000) for males and -1.84% (Z = -6.02,P = 0.000) for females, while the APC of standard mortality rate was -4.60% ( Z = -15.79, P = 0.000) for females and -5.36% ( Z = -8.28, P = 0.000) for males during 1989-2002. Mortality and incidence ratio also indicated a downward trend.

CONCLUSIONDespite its declining trend in Tianjin, gastric cancer still remains an important public health problem in facing of the aging society and many risk factors.

Adolescent ; Adult ; Aged ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Incidence ; Infant ; Infant, Newborn ; Male ; Middle Aged ; Risk Factors ; Stomach Neoplasms ; epidemiology ; mortality ; Survival Rate

Objective To explore the diagnosis and therapy experience of vascular ring combined with tracheal compression in infants and neonates.Methods Sixteen cases(including 7 boys and 9 girls,aged 1 day to 12 months)with vascular ring combined with tracheal compression hospitalized in Guangdong General Hospital from Jun.2004 to Dec.2009 were enrolled.In these 16 children,13 cases had congenital heart malformations.All children underwent X-ray,echocardiography and spiral computed tomography examination.Nine cases received bronchoscopy study.Fifteen cases performed surgical division of vascular ring with cardiopulmonary bypass and 1 case underwent vascular ring division and tracheoplasty.Eleven cases received management of congenital heart defect simultaneously.Results Vascular ring anomalies included pulmonary artery sling in 5 children,right aortic arch-left ligmentum/aberrant left subclavian artery in 8 cases,double aortic arch in 1 case,innominate artery compression in 1 case,and pulmonary sling combined with right aortic arch-aberrant left subclavian artery in 1 case.There were 2 ring-sling complex cases in this study.The diagnosis of vascular ring were correctly made by echocardiography in 7 children and made by spiral computed tomography in all 16 cases.Two cases combined with tracheal ring died.In the follow-up study of 11 cases,5 cases were still vulnerable to wheezing.Conclusions The common presentation of tracheal compression in infants and neonates associated with vascular ring are tachypea,stridor,and dyspnea.Multi-slices spiral computed tomography is an important imaging modality.Surgical divisions of vascular ring are safe procedure in most cases and tracheal compression can be relieved by this operation.In patients with severe tracheal stenosis,tracheoplasty should be recommended.

OBJECTIVETo observe the changes of matrix metalloproteinases (MMPs) activities in pulmonary fibrosis rats.

METHODSEighty male SD rats were randomly divided into sham group (n = 40) and bleomycin group (BLM, n = 40), in which SD rats were injected with a single intratracheal dose of sham saline or bleomycin respectively. On day 1, 3, 7, 14, and 28 following bleomycin or saline instillation, rats were randomly killed, and serum from abdominal aorta, alveolar fluid from the bronchoalveolar lavage, and the lung homogenate were collected and then stored at -80 degrees C. MMPs activity was determined by zymography.

RESULTSCompared with sham group, the levels of MMP-9 in all samples were augmented. MMP-9 activities in the serum were highest on day 3 than those on day 1 and day 7, and in lung tissue homogenate were highest on day 7; however, no significant differences were found between BLM group and sham group on day 14 and day 28; and that of bronchoalveolar lavage fluid (BALF) was highest on day 7 than those on day 1 and day 14, while no significant difference existed between BLM group and sham group on day 28. Serum MMP-2 level did not change from day 1 to day 28, while the level of BALF MMP-2 began to increase after day 14, even on day 28. Lung tissue homogenate MMP-2 level began to increase early on day 3 and continued to day 28.

CONCLUSIONThe sources and effects of MMP-2 and MMP-9 differ in BLM-induced rat pulmonary fibrosis.

Animals ; Bleomycin ; toxicity ; Disease Models, Animal ; Male ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Pulmonary Fibrosis ; chemically induced ; enzymology ; Rats ; Rats, Sprague-Dawley

China ; epidemiology ; Colonic Neoplasms ; epidemiology ; mortality ; Female ; Humans ; Incidence ; Male

OBJECTIVEAlkaline comet assay was used to evaluate DNA repair (nucleotide excision repair, NER) capacity of human fresh lymphocytes from 12 young healthy non-smokers (6 males and 6 females).

METHODSLymphocytes were exposed to UV-C (254 nm) at the dose rate of 1.5 J/m2/sec. Novobiocin (NOV) and aphidicolin (APC), DNA repair inhibitors, were utilized to imitate the deficiency of DNA repair capacity at the incision and ligation steps of NER. Lymphocytes from each donor were divided into three grougs: UVC group, UVC plus NOV group, and UVC plus APC group. DNA single strand breaks were detected in UVC irradiated cells incubated for 0, 30, 60, 90, 120, 180, and 240 min after UVC irradiation. DNA repair rate (DRR) served as an indicator of DNA repair capacity.

RESULTSThe results indicated that the maximum DNA damage (i.e. maximum tail length) in the UVC group mainly appeared at 90 min. The ranges of DRRs in the UVC group were 62.84%-98.71%. Average DRR value was 81.84%. The DRR difference between males and females was not significant (P < 0.05). However, the average DRR value in the UVC plus NOV group and the UVC plus APC group was 52.98% and 39.57% respectively, which were significantly lower than that in the UVC group (P < 0.01).

CONCLUSIONThe comet assay is a rapid, simple and sensitive screening test to assess individual DNA repair (NER) capacity. It is suggested that the time to detect DNA single strand breaks in comet assay should include 0 (before UV irradiation), 90 and 240 min after exposure to 1.5 J x m(-2) UVC at least. The DRR, as an indicator, can represent the individual DNA repair capacity in comet assay.

Adult ; Aphidicolin ; pharmacology ; Comet Assay ; methods ; DNA Damage ; drug effects ; radiation effects ; DNA Repair ; drug effects ; genetics ; radiation effects ; Enzyme Inhibitors ; pharmacology ; Female ; Humans ; Lymphocytes ; drug effects ; metabolism ; radiation effects ; Male ; Novobiocin ; pharmacology ; Risk Assessment ; Time Factors ; Ultraviolet Rays ; adverse effects