It has been suggested that melatonin is involved in learning and memory. In the present study, we investigated the effects of melatonin on spatial learning and memory in rats, using Morris water maze and electrophysiological methods. The results are as follows. (1) During a six-day water maze training, the mean escape latency of melatonin group in the last 4 days was 30.02+/-3.6 s, and that of control group was 18.44+/-2.7 s (P<0.01). The crossing annulus coefficient of melatonin group was 25.68+/-2.32%, and that of control group was 43.33+/-2.85% (P<0.01). (2) Microinjection of melatonin into CA1 area inhibited long-term potentiation (LTP). Sixty minutes after tetanus, the field excitory postsynaptic potentials (fEPSP) slope of group C (n=7 0.5 microliter saline) was 169.71+/-6.48 % of the baseline, and that of group M2 (n=6, 2 microgram melatonin) was 114.28+/-1.80% of the baseline. The difference is significant (P<0.01). (3) We also investigated the effects of melatonin on LTP after administration of scopolamine. Sixty minutes after tetanus, the fEPSP slope of group SM (n=6, 2 microgram scopolamine before 2 microgram melatonin) was 113.70+/-5.55% of the baseline. It showed a significant decrease compared with group C (P<0.01). However, there was no difference between groups SM and M2 (P>0.05, i.v.). The results obtained by applying melatonin after bicuculline were different from those after scopolamine. Sixty minutes after tetanus, the fEPSP slope of group BM (n=7, 1 microgram bicuculline before 2 microgram melatonin) was 162.29+/>10.52% of the baseline. Compared with group C, there is no significant difference (P>0.05); but compared with group M2, the difference is significant (P<0.01). Our results showed that application of melatonin in rats significantly inhibited not only spatial learning and memory, but also LTP in CA1 area. Furthermore, the results indicate that the inhibition of LTP by melatonin may not be mediated by cholinergic system, but may be through the modulation of GABAergic system.
Animals ; Bicuculline ; pharmacology ; Female ; Hippocampus ; drug effects ; physiology ; Learning ; drug effects ; Long-Term Potentiation ; drug effects ; Male ; Melatonin ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Scopolamine Hydrobromide ; pharmacology ; Space Perception ; drug effects

Objective To assess the value of CT perfusion imaging in differentiation of mild from moderate liver fibrosis .Methods 18 patients with mild liver fibrosis (F1 phase) and 21 ones with moderate fibrosis (F2 and F3 phase) confirmed by liver biopsy were analyzed ,and all patients underwent the liver 256‐slice CT perfusion imaging .The differences in the CT parameters including hepatic arterial perfusion (HAP) ,portal venous perfusion (PVP) ,total liver perfusion (TLP) and time to peak (TTP) between dif‐ferent fibrosis were analyzed .ROC curve was used to evaluate the ability of perfusion indexes to distinguish mild from moderate liver fibrosis ,then the maximum Youden index was selected as a cutoff point to calculate the sensitivity and specificity .Results Compared with the mild fibrosis ,the TTP [(43 .86 ± 13 .41)s vs (37 .84 ± 9 .97)s ,P=0 .034)] in liver with moderate fibrosis was significantly increased .However ,no differences in the HAP ,PVP and TLP were found .The ROC curve analysis showed that a TTP threshold of 41 .7 s allowed discrimination of mild from moderate fibrosis with a sensitivity of 72 .7% and a specificity of 75% .Conclusion 256‐slice CT perfusion imaging can reflect the hemodynamic changes of liver fibrosis ,and the TTP may help to discriminate mild from moderate fibrosis .

OBJECTIVETo study the effects of the superficial venous trunk (SVT) and its nourishing vessels on early revascularization of the reverse-flow random flap in order to provide theoretical evidences for clinical applications.

METHODSThe morphologic changes of micrangium of the reverse-flow random flap with SVT and without SVT were observed at different phases and compared by optical microscopy and stereological methods.

RESULTSThe micrangium density of the flaps with SVT and without SVT showed a tendency of increasing at 3 days after the operation. At 5 to 10 days, the micrangium density of the flap with SVT was much higher than the flap without SVT. There was significant difference between the two groups, which was proved by the optical microscopy observation.

CONCLUSIONSThis study suggests that SVT and its nourishing vessels could promote early revascularization of the flap after transplantation. The SVT can be of benefit to the survival of the reverse-flow random flap.

Animals ; Graft Survival ; Microcirculation ; Reconstructive Surgical Procedures ; methods ; Skin Transplantation ; Surgical Flaps ; blood supply ; Swine ; Swine, Miniature ; Veins ; transplantation

OBJECTIVETo study the influence of manufacture technique on the translucency and color of dental porcelain.

METHODSSpecimens were made of VITA VMK 95 dentin porcelain and enamel porcelain and divided into 3 groups: Sintering times group (1, 2, 4, 6, 8 and 10 times), sintering temperature group (910, 920, 930, 940 and 950 degrees C), sintering vacuum group (95, 65, 35 and 0 kPa). Transmittance, Y, dominant wavelength and saturation were measured by PR-650 spectra scan spectrocolorimeter.

RESULTSTransmittance of dentin porcelain increased after 6 times repeated sintering. Transmittance of enamel porcelain increased first after the second sintering, and then became decreasing when sintering more than 2 times. Transmittance of enamel porcelain deceased when sintering temperature was lower than standard. Decrease of sintering vacuum caused the transmittance of dentin and enamel porcelain decreased. The changing of value was coordinated with transmittance. Dominant wavelength and saturation had negative correlation with sintering times and temperature, and positive correlation with vacuum.

CONCLUSIONSintering times, temperature and vacuum all had prominent effects on the translucency and color of dental porcelain. Comparing with dentin porcelain, enamel porcelain was more sensitive with the modification of manufacture technique.

Color ; Dental Alloys ; Dental Enamel ; Dental Porcelain ; Dentin ; Humans ; Temperature

The objective of this study was to develop research of cardiac cells to reestablish 3D tissue architecture in vitro, we performed studies using collagen membrane as three-dimensional scaffold for cardiac cells culture with the principles and methods of tissue engineering. The polymer scaffold provides a 3-D substrate for cell attachment and tissue formation. Cardiac cells isolated by enzymatic digestion from 1d old neonatal rats were seeded to three-dimensional collagen scaffolds and tissue culture plates. The morphology, beating rate and the metabolic indexes, including specific consumption rate of glucose (q(glu)) , specific production rate of lactate (q(lac)), lactate transform rate ( Y(lac/glu)), specific creatine kinase (CK) and lactate dehydrogenase (LDH) activities of cardiac cells cultured on three-dimensional collagen membrane and tissue culture plates were compared. It was found that cells shape and cells' CK and LDH activity was no differences between 3D and 2D cultures and cell beat rate on cell culture cluster was slower than those cells cultured on collagen membrane, However the cell glucose consumption and lactate yield rate of cells cultured on cluster was higher than those cells cultured on collagen membrane. After 5 days of cultivation, cardiac cells cultured on collagen membrane scaffolds organized into three-dimensional (3D) aggregates as opposed to the two-dimensional (2D) aggregates mosaic pattern seen in tissue culture plates, and spontaneous and rhythmical contractile 3D cultures in unison were visible to the naked eye and the area of synchronous contract three-dimensional (3D) aggregates reaches 80cm2. The mean value of q(glu), q(lac) and Y(lac/glu) of cultured on three-dimensional collagen scaffold was 7.37 micromol/10(6) cells/d, 2.92 micromol/10(6) cells/ d and 0.38 micromol/micromol, versus 7.59 micromol/10(6)cells/d, 3.83 micromol/10(6) cells/d and 0.51 micromol/micromol in tissue culture plates. These results demonstrate that cardiac cells immobilized on collagen membrane in 3D cultures maintain similar metabolic activity and contractile function when compared with native cardiac cells. The above results support the idea that engineered cardiac tissue can be used as a model of native tissue for studies of tissue development and function in vitro and eventually for tissue repair in vivo.
Animals ; Biocompatible Materials ; chemistry ; Cells, Cultured ; Collagen ; chemistry ; Flow Cytometry ; Immunohistochemistry ; Microscopy, Electron, Scanning ; Myocytes, Cardiac ; cytology ; ultrastructure ; Rats ; Rats, Wistar ; Tissue Engineering ; methods ; Tissue Scaffolds ; chemistry

OBJECTIVETo evaluate the correlation between arteriosclerotic risk factors and the severity of benign prostatic hyperplasia (BPH).

METHODSA total of 877 patients with diagnosed BPH were selected according to the inclusion criteria. The weight of the prostate was estimated by transrectal ultrasonography, the degree of bladder outlet obstruction determined by urodynamic examination, and the symptoms quantified by the International Prostate Symptom Score (IPSS). Arteriosclerotic risk factors included age, hypertension, dyslipidemia, type 2 diabetes mellitus, and smoking. Comparative studies were made on the data obtained by univariate and multivariate analyses.

RESULTSThe severity of BPH was increased with the increase in the severity of the risk factors and the incidence of the disease. The logistic regression analysis showed that type 2 diabetes mellitus was a prominent predictor of the prostate volume, IPSS and degree of bladder outlet obstruction (OR = 3.179, 3.862 and 2.847, P < 0.001), while the level of serum triglyceride was not (P > 0.05). Age, hypertension, high LDL, low HDL and smoking were all prominent predictors of the severity of BPH.

CONCLUSIONArteriosclerotic risk factors are obviously correlated with the development and severity of BPH, among which type 2 diabetes mellitus is the most important.

Aged ; Aged, 80 and over ; Arteriosclerosis ; pathology ; Diabetes Mellitus, Type 2 ; pathology ; Humans ; Male ; Middle Aged ; Prostate ; pathology ; Prostatic Hyperplasia ; pathology ; Risk Factors ; Urinary Bladder Neck Obstruction ; pathology

OBJECTIVETo investigate whether there are different stromal compositions in the prostate tissue of patients with benign prostatic hyperplasia (BPH) and evaluate their significance in the course of the disease.

METHODSForty-three surgical or bioptic prostatic specimens of BPH and 5 autoptic normal prostatic specimens were stained by the Masson method to display the elements of the muscle fiber and collagen. The relationship of the changes in the prostatic stromal composition was analyzed with the degree of bladder outlet obstruction (BOO) , IPSS and medication results.

RESULTSThe mean ratio of muscle fiber to collagen in the normal prostate tissue was (3.2 +/- 0.2):1, significantly higher than that of the BPH patients (1: [4.7 +/- 3.1] ) (P < 0.01); that in the BPH patients with BOO was 1: (5.4 +/- 3.7) markedly lower than in those without BOO (1: [2.5 +/- 1.1] ) (P = 0.02); that in the BPH patients with severe prostatic symptoms was 1: (9.1 +/- 2.9), remarkably lower than in those with moderate (1: [5.3 +/- 3.4]) and mild prostatic symptoms (1: [2.8 +/- 1.7]) (P < 0.01); and that in the BPH patients with satisfactory medicinal therapeutic results was 1:(2.3 +/- 1.9), significantly higher than in those with poor therapeutic results (1: [7.6 +/- 4.3]) (P < 0.01).

CONCLUSIONThe stromal composition in the prostatic tissue of BPH patients undergoes different degrees of changes. More obvious BPH symptoms and poorer therapeutic results are associated with a bigger proportion of collagens and a smaller proportion of muscle fibers in the prostatic tissue. These changes may play an important role in the development and progression of BPH.

Aged ; Aged, 80 and over ; Case-Control Studies ; Fibrosis ; Humans ; Male ; Middle Aged ; Prostate ; pathology ; Prostatic Hyperplasia ; pathology ; Urinary Bladder Neck Obstruction ; pathology

OBJECTIVETo study the inhibitory effect of T-2 toxin on the expression of aggrecan and collagen II in chondrocytes and the protection of selenium against this effect.

METHODSHuman chondrocytes cultured in vitro were treated with T-2 toxin at different concentrations for varied time periods (1-5 days), and the cell viability was measured by MTT assay. Aggrecan expression was detected by toluidine blue staining and collagen II expression by immunostaining using monoclonal antibody of collagen. Aggrecan and collagen II mRNA expressions were measured by semiquantitative RT-PCR.

RESULTST-2 toxin dose- and time-dependently affected chondrocyte viability within the concentration range of 0.001-2 mg/L, the prolonged treatment time further enhanced the dose dependence of the inhibitory effect. T-2 toxin lowered aggrecan and collagen II synthesis in the chondrocytes and reduced their mRNA expressions. Selenium could partly attenuate the inhibitory effects of T-2 toxin on aggrecan mRNA expression, but showed no such effect against T-2-induced collagen II expression.

CONCLUSIONT-2 toxin can obviously inhibit aggrecan and collagen II synthesis in human chondrocytes, and selenium can partly antagonize the inhibitory effects of T-2 toxin on aggrecan.

Aggrecans ; biosynthesis ; genetics ; Cells, Cultured ; Chondrocytes ; cytology ; metabolism ; Collagen Type II ; biosynthesis ; genetics ; Dose-Response Relationship, Drug ; Fetus ; Humans ; Protective Agents ; pharmacology ; RNA, Messenger ; biosynthesis ; genetics ; Selenium ; pharmacology ; T-2 Toxin ; toxicity

OBJECTIVETo study the role of changes of matrix metalloproteinase-2, 9 (MMP-2, 9) activity in the development of dimethylnitrosamine (DMN)-induced liver fibrosis in rats.

METHODSThe rat liver fibrosis model was established by peritoneal injection of DMN (at a dose of 10 mg/kg, 3 times a week, for 4 weeks). The dynamic changes of liver fibrosis were observed at different time points (1d, 2d, 3d, 1 week, 2 weeks, 4 weeks, 6 weeks and 8 weeks). The MMP-2, 9 activity was measured by zymogram method. Liver ultrastructure was observed by electron microscope. The expressions of type IV collagen (CIV), laminin (LN), type I collagen (CI) and alpha-smooth muscle actin (alpha-SMA) were examined by immunohistochemistry. The tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) content was measured by Western blot method.

RESULTSThe MMP-2, 9 activity (gray value) significantly increased in the 2d and 3d DMN model rats (2d: normal/model group, MMP-2: 54.72+/-4.56/70.76+/-7.63; F = 16.27, P < 0.05; MMP-9: 25.72+/-4.29/51.76+/-15.33, F=13.38, P < 0.05). The positive staining area percentage of CIV in the sinusoidal walls decreased in the 2d, 3d and 1 weeks model rats (2d: normal/model group, 6.06+/-1.35/2.86+/-0.63, F=69.12, P < 0.05), but significantly increased in the 4w model rats (normal/model group, 6.06+/-1.35/8.04+/-1.50, F=14.42, P < 0.05). There was a remarkable negative correlation between the MMP-9 activity and expression of CIV in the sinusoidal walls (r = -0.729, P < 0.05). Positive expressions of LN and CI increased, and the strongest positive staining of them displayed in the 4w model rats. The formation of basement membrane was also observed in the 4 weeks model rats. Expression of TIMP-2 significantly increased in the late stage of fibrosis.

CONCLUSIONSThe increase of MMPs activity, especially MMP-9 which degrades the CIV normally distributed under the sinusoidal endothelium is the important factor in the formation of sinusoidal capillarization. The deposition and reconstitution of LN and new synthetic CIV, adding the deposition of CI constitute the high density basement membrane. The increase of TIMP-2 expression in the late stage of the fibrosis may be one of reasons why natural resolution of DMN-induced liver fibrosis is difficult.

Animals ; Collagen Type IV ; analysis ; Laminin ; analysis ; Liver ; chemistry ; ultrastructure ; Liver Cirrhosis, Experimental ; enzymology ; pathology ; Male ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Rats ; Rats, Wistar ; Tissue Inhibitor of Metalloproteinase-2 ; analysis

OBJECTIVETo study the clinical problems about posterior atlanto-axial internal-fixation and fusion for atlanto-axial instability or dislocation.

METHODSSurgical treatments of 138 cases with atlanto-axial instability or dislocation were reviewed. There were 62 cases of odentoid malformation, 54 cases of odentoid fracture or rupture of transverse ligament, 22 cases of subluxation and rotation. All cases were treated using Gallie's technique. Six cases were also fixed with transarticular screws, and protected with Philadelphia collar. Other patients were fixed with plaster paris brackets. The followed-up period was 1 to 12 years with an average of 3 year and 5 months.

RESULTSAccording to Sumi's criteria, excellent 70 cases (50.7%), good 40 cases (29.0%), fair 15 cases (10.9%), poor 13 cases (9.4%). 9 cases with bone graft postponed fusion were cured by enhance external-fixation. 2 cases with nonunion were treated with revision surgery. Complication of cord injury happened in 1 case.

CONCLUSIONGallie's fusion technique is an effective method to manage the atlanto-axial instability or dislocation. Skull distraction before operation and reliable external-fixation post operative are important assistant measures. Key points for successful operation are careful wiring or cable traversing, decortication of posterior arc of C1, and maintaining the physiological height between C1 and C2 posterior arc. Indications and objectives should be conformed before revision surgery for failure cases.

Adolescent ; Adult ; Atlanto-Axial Joint ; surgery ; Bone Transplantation ; Child ; Female ; Humans ; Joint Dislocations ; surgery ; Joint Instability ; surgery ; Male ; Middle Aged ; Retrospective Studies ; Spinal Fusion ; adverse effects ; methods ; Transplantation, Autologous