The phenomenon of recessive absence was initiated by many malpractices in current medical educational system.In this article we try to analyze this phenomenon,speculate the subjective and objective reasons,propose countermeasures such as improving teachers quality,reforming traditional teaching mode,strengthening medical ethics education,enriching teaching means and addressing student-centered lectures.

ObjectiveTo study the effect of testing amino acids levels in brain microdialysate by method of high performance liquid chromatography (HPLC) with α-aminobutyric acid (AABA) as the internal standard.MethodsReversed phase high performance liquid chromatography (RP-HPLC), orthophthaladehyde (OPA) precolumn derivatization method and fluorescence detector were used. The separation was performed using an ODS-C18 column. AABA, an isomeric compound of GABA, served as the internal standard, phosphate buffer solution and methanol as the mobile phase, gradient elution lasted in 35 min.Results7 kinds of amino acids and internal standard were separated completely. The mean recovery of amino acid was 88.2%—102.3%. The mean correlation coeffeicient of the linear relationship was 0.998±0.0015.Limits of detection for amino acids were 1.0—8.6 ppm respectively.ConclusionThe method mentioned above is simple and sensitive for operation, and can be used for determined levels of amino acids in microdialysate.

Cerebral Infarction ; drug therapy ; etiology ; Female ; Humans ; Infant, Newborn ; Intracranial Hemorrhages ; drug therapy ; etiology ; Male ; Vitamin K Deficiency ; complications ; drug therapy

Angiotensin II ; metabolism ; Cisplatin ; adverse effects ; Humans ; Kidney ; drug effects ; Kidney Diseases ; chemically induced ; metabolism

OBJECTIVEThe aim of this study is to investigate the effects of irradiation on the proliferation and differentiation of MC3T3-E1 osteoblastic cells.

METHODSMC3T3-E1 cells were irradiated 24 h after initial seeding. Gamma-radiation was administered at 0, 4, and 8 Gy as single doses by using a 60Co source. Cell proliferation was assessed at days 1, 3, 5, and 7 post-irradiation by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide assay. The collagen secretion of the cells was measured through sirius red staining at day 12 post-irradiation. The expressions of osteogenesis-related genes were assessed through real time fluorescence quantitative polymerase chain reaction at day 16 post-irradiation. The matrix mineralization caused by cells was evaluated through alizarin red staining at day 28 post-irradiation.

RESULTSThe cells exposed to 4 Gy or 8 Gy demonstrated significantly lower proliferation rates compared with the non-irradiated group. Doses of 4 Gy or more significantly inhibited the expressions of osteogenesis-related genes (Osterix and osteocalcin). Collagen secretion and cell mineralization were significantly reduced by the 8 Gy dose.

CONCLUSION60Co gamma-rays dose-dependently suppress the proliferation, collagen secretion, and mineralization of MC3T3-E1 cells. Furthermore, radiation seems to dose-dependently inhibit the expressions of osteogenesis-related genes of the cells.

Cell Differentiation ; Cell Line ; Cell Proliferation ; Humans ; In Vitro Techniques ; Osteoblasts ; Osteocalcin ; Osteogenesis

Animals ; Colorectal Neoplasms ; metabolism ; pathology ; Epithelial-Mesenchymal Transition ; Humans ; Insulin-Like Growth Factor I ; metabolism ; Neoplasm Metastasis ; Signal Transduction ; Transforming Growth Factor beta ; metabolism ; Wnt Signaling Pathway

Objective To evaluate the feasibility of contrast material on image quality of coronary CT angiography (CCTA)by using double injection technology and iterative reconstruction.Methods 120 patients with suspected coronary heart disease who underwent CCTA were randomly divided into two groups.Then,60 patients with 30 kg/m2>BMI≥25 kg/m2 were averagely divided into A1 and B1 groups,and other 60 ones with BMI<25 kg/m2 were also averagely divided into A2 and B2 groups.The patients in group A were scanned with 120 kV tube output and iolromide 350 mg I/mL,and the images were reconstructed using filtered back projection (FBP).Meanwhile,the patients in group B were scanned with 80 kV or 100 kV tube output and 245 mg I/mL or 280 mg I/mL of contrast media (BMI≥25 kg/m2 )using double injection technology,and the images were reconstructed using adaptive iterative dose reduction 3D (AIDR 3D).The effective radiation dose (ED)of each patient was also calculated.CT attenuation of the main proximal vessels (ascending or descending aorta,pulmonary artery,RCA,LM,LAD and LCX)and the obj ective image quality (SD,CNR and SNR)were measured,and the subj ective evaluation was also assessed by an experienced radiologist.Results There was significant differences in mean image quality scores,SD,SNR and CNR of ascending aorta between group A1 and B1(P<0.05),but no difference in the SI of values (P>0.05).There was no significant difference in mean image quality scores between group A2 and B2 (P>0.05), however,there were significant differences in the SI,SD of values and SNR,CNR of ascending aorta (P<0.05).The values of BMI were negatively related to the values of CT in ascending aorta between two subgroups (r=-0.66 and -0.441,P<0.05).The values of weight were not related to the values of CT in ascending aorta (P>0.05).There was significant difference in effective dose between subgroups (P<0.05).Conclusion The method with a combination of iterative reconstruction and a contrast material of 245 mg I/mL using double inj ection technology can improve the contrast enhancement without impairing image quality.

Objective To investigate the bid gene expression and cell death in brain after cerebral hypoxia-ischemia in neonatal rats and the effects of dexamethasone(DEX)on bid gene expression,so as to elucidate the possible mechanism of the neuroprotective effect of DEX pretreatment on rats following cerebral hypoxia-ischemia.Methods Twenty-four SD neonatal rats were divided randomly into hypoxia-ischemia brain damage(HIBD),normal,dexamethasone-pretreated and 9 g/L NaCl(NS)control group.The animal models of HIBD were made.Total RNA from ipsilateral cerebral hemisphere was extracted.Reverse transcription polymerase chain reaction(RT-PCR)was used to evaluate the level of bid gene expression after hypoxia-ischemia.Cerebral apoptosis was determined by terminal-deoxynucleotidy transferase mediated d-UTP nick end labeling(TUNEL).Results The levels of bid mRNA were higher in HIBD rats than those in normal rats.The number of positive apoptosis cells significantly increased in HIBD group(P

Objective To explore the cellular inhibitor of apoptosis protein 1(cIAP1)gene expression and Caspase-3 activity in brain after cerebral hypoxia-ischemia in neonatal rats and the influence of dexamethasone(DEX)on cIAP1 gene expression and Caspase-3 activity,so as to elucidate the possible mechanism of the neuro-protective effect of DEX pretreatment on rats following cerebral hypoxia-ischemia.Methods Twenty-four SD neonatal rats were divided randomly into hypoxic-ischemic brain damage group(HIBD group),normal group(NS group),dexamethasone-pretreated group(DEX group)and 9 g/L NaCl control group(NS group).The animal models of HIBD were made.Total RNA from ipsilateral cerebral hemisphere was extracted.Reverse transcription polymerase chain reaction(RT-PCR)was used to evaluate the level of cIAP1 gene expression after hypoxia-ischemia.Caspase-3 relative activity of brain tissue was determined by colorimetric assay.Results The levels of cIAP1 mRNA were lower in HIBD group than those in NS group.Caspase-3 relative activity significantly increased in HIBD group(P

OBJECTIVEThe quantity and genus of fungi on 13 samples of American ginseng seed from Beijing and Northeast area in China were detected.

METHODWashing and surface sterilization were used to isolate the fungi existed on seed surface and inside of the seed, respectively.

RESULTThe genera of the fungi in embryo and shell of the seeds mainly belonged to Fusarium spp., Alternaria spp., Penicilium spp., Cephalosporium sp., Rhizopus spp., and a small quantity of Mucor, Aspergillus, Tritroderma, Doratomyces and so on. The isolated fungal frequencies on the shell and in the embryo were 36%-100% and 40%-100% respectively.

CONCLUSIONThe fungal frequency of American ginseng seed was higher. There were significant differences among different seed samples, the main fungal genera and isolation frequency in the seed embryo were identical with the results from the seed shell.

Alternaria ; isolation & purification ; China ; Fusarium ; isolation & purification ; Mitosporic Fungi ; isolation & purification ; Panax ; classification ; microbiology ; Plants, Medicinal ; microbiology ; Rhizopus ; isolation & purification ; Seeds ; microbiology