OBJECTIVEThis study aims to identify the crack tip stress intensity factor of the propagation process, crack propagation path, and the changes in the shape of the crack tip by the finite element method.

METHODSThe finite element model of dentino-enamel junction was established with ANSYS software, and the length of the initial crack in the single edge was set to 0.1 mm. The lower end of the sample was fixed. The tensile load of 1 MPa with frequency of 5 Hz was applied to the upper end. The stress intensity factor, deflection angle, and changes in the shape of the crack tip in the crack propagation were calculated by ANSYS.

RESULTSThe stress intensity factor suddenly and continuously decreased in dentino-enamel junction as the crack extended. A large skewed angle appeared, and the stress on crack tip was reduced.

CONCLUSIONThe dentino-enamel junction on human teeth may resist crack propagation through stress reduction.

Dental Enamel ; Dentin ; Humans ; Stress, Mechanical ; Tooth Fractures

Objective To study the function and diurnal variation of hypothalamic-pituitary-adrenal (HPA) axis and hypothalamic-pituitary-thyroid(HPT) axis,and the relationship with clinical characteristics of di-urnal rhythm in depressed patients. Methods Forty-nine depressed patients met diagnostic DSM-Ⅳ criteria and thirty-eight normal controls were collected. The plasma levels of cortisol (CORT), adrenocorticotropic hormone (ACTH), T3, T4, thyroid-stimulating hormone (TSH) at 7 am and 7 pm were measured by radioimmunoassay, then the results concemed were compared among the depressed groups with and without diurnal variation and control group by multivariate analysis of variance. Results The plasma level of morning CORT, morning and evening TSH ((365.94±120.78) nmol/L; (6.24±2.47)μIU/ml; (6.68±2.42)μIU/ml; respectively) were respective-ly higher than those of control group((284.91±83.39) nmol/L; (3.82±1.75)μIU/ml;(4.01±1.69)μIU/ ml, P<0.05). The plasma levels of morning and evening T4 were significantly lower than those of control group(P <0.05). The CORT morning-evening difference variable distinguished between depressed and control group (P< 0.001),but no significant differences could be found between the depressed groups with and without diurnal varia-tion. There were no significant differences in the CORT, T3, T4, TSH morning-evening difference variable between various clinical subtypes of depressed patient (unipolar/bipolar; psychotic/nonpsychotic). Conclusion Abnormal CORT morning-evening difference variable was observed in the depressed patients compared with normal controls,and may be used as a special trait mark of depressed group.

Background Porcine fibrin sealant kit has been widely used in surgery for clotting and woundssealing.It is thought to be a substitution for inert gas and silicone oil in vitrectomy.But whether it produce toxic effect on retina or not after intravitreal injection is still studying.Objective This study aimed to investigate the retinal toxicity of porcine fibrin sealant kit following intraocular application.Methods Vitrectomy was performed on bilateral eyes of 15 pigmented rabbits.Porcine fibrin sealant kit of 0.5 ml was intravitreally injected in the lateral eyes of the rabbits as the experimental group,and equal volume of BSS was used at the same way in contralateral eye as control group.The inflammatory response of eye was observed under the slit lamp and ophthalmoscopy in 1 day,3,7,15,30 days after injection.Schi(o)tz tonometer was used to measure intraocular pressure(IOP) in 1 day,3,7 days,and retinal function was evaluated by electroretinogram (ERG) before operation and 30 days after operation.B-ultrasonic examination was carried out 30 days after surgery.Animals were sacrificed and eyeballs were obtained for retinal histopathological and ultrastructural examination in 30 days after operation.Results Complications appeared in 7 eyes of the experimental group,including cataract in 3 eyes,proliferation vitreoretinopathy and retinal detachment in 5 eyes,endophthalmitis in 1 eye,however,the cataract in 2 eyes and retina injury in 2 eyes were found in 15 control eyes.On the 30 days after injection,no inflammation was found in the 8 eyes without complication in the experimental group and 11 eyes in the control group.The IOP change was insignificant in different groups and various time points (Fgroup =0.008,P =0.929 ;Ftime =3.600 P =0.075).No significant difference was found in a-wave amplitude between groups and various time points(Fgroup =0.728,P =0.405 ; Ftime =0.516,P =0.482),and so was the b-wave amplitude (Fgroup =0.222,P =0.644 ; Ftime =0.057,P =0.814).On the 30th day after operation,arrangement of the retina was regular and no tissue edema and inflammatory cell infiltration were seen in both groups under the light microscope.Transmission electron microscope revealed that the ultrastructures of retinal cells,photoreceptor and retinal pigment cell were normal with the clear subcellular organelle,intact cellular membrane structure and mitochondria in both groups.Conclusions Domestic porcine fibrin sealant kit does not produce toxic effect on retina after intravitreal injection in rabbit.

OBJECTIVETo provide new germplasm materials for breeding new varieties of Pseudostellaria heterophylla.

METHODThe method of single plant selection was adopted, with the comparative experiments being carried out under the same conditions in Shibing county. The 8 plants of Shibing SB-4 were compared respectively with factor analysis for 27 phenotypic traits and 8 yield traits, and single factor variance analysis for the contents of polysaccharides.

RESULTUsing factor analysis, 27 phenotypic traits were classified into 7 principal divisors and 8 yield traits were simplified into 3 principal divisors. The 4 strains of P. heterophylla, ZT-01, ZT-02, ZT-06 and ZT-07, performed better than others in the phenotypic traits, and ZT-01, ZT-02, ZT-03 and ZT-07 in the yield traits. The contents of polysaccharides of ZT-01, ZT-02, ZT-05 and ZT-08 showed significantly higher value.

CONCLUSIONThere is significant difference among the 8 strains of P. heterophylla in phenotypic traits, yield traits and quality traits, making it possible to select certain strains for different purposes. ZT-01 and ZT-02 can be breaded further. ZT-06 and ZT-07 were used as ornamental cultivars for its great phenotypic traits. ZT-03 with good resistance and high yield was taken as resistant variety, and ZT-05 would face next selection on the basis of its high content of polysaccharide.

Breeding ; Caryophyllaceae ; chemistry ; growth & development ; China ; Phenotype ; Polysaccharides ; analysis

Chronic pain is a common clinical manifestation in patients with advanced cancer, and pain treatment is a part of cancer treatment. The titration method of opiod drugs will be recommended for relieving pain in moderate-severe pain in order to improve the quality of life of patients with advanced cancer. Individualized pain control refers to the concept that different patients show different resistance responses to opiod drugs. This article briefly reviews the classification and mechanism of cancer pain, the titration method of opiod drugs in the cancer pain control and individualized application.

Objective:To observe the effect of Zhen'ai needling method in Nei Jing (Classic of Internal Medicine) on quality of life in patients with allergic rhinitis (AR).Methods:A total of 99 patients with AR who met the inclusion criteria were randomized into a conventional needling group (51 cases) and a Zhen'ai needling group (48 cases).The conventional needling group was treated with acupuncture at Zusanli (ST 36),Hegu (LI 4),Juliao (ST 3),Yingxiang (LI 20),Yintang (GV 29),Shangxing (GV 23) and Baihui (GV 20).The Zhen'ai needling group added acupoints of Zhen'ai needling method {Lieque (LU 7),Shanglianquan [Extra,located at 1 cun above Lianquan (CV 23)] and Tianrong (SI 17)} in addition to points in the conventional needling group.The needles were retained for 30 min.The treatment was performed twice a week.All patients were assessed by total nasal symptom score (TNSS),total ocular symptom score (TOSS) and sino-nasal outcome test-20 (SNOT-20) before and after 15 treatments to evaluate the quality of life.The clinical efficacy was evaluated after 15 treatments.Results:During the treatment,8 cases dropped out in the conventional needling group and 7 cases in the Zhen'ai needling group.There were no significant differences in TNSS,TOSS and SNOT-20 scores between the two groups before treatment (all P＞0.05).After treatment,the total effective rate of the Zhen'ai needling group was 92.7％,versus 88.4％ in the conventional needling group.There was no significant difference between the two groups (P＞0.05).After treatment,there were no significant differences between the two groups in TNSS and TOSS scores (both P＞0.05).The SNOT-20 score of the Zhen'ai needling group was lower than that of the conventional needling group,and the difference was statistically significant (P＜0.05).There were statistical differences between the two groups in the scores of cough and nasal reflux (to the throat) of the NOT-20 scale (both P＜0.05).Conclusion:Both Zhen'ai needling method and conventional acupuncture are effective in the treatment of AR.Zhen'ai needling method has a better effect than conventional acupuncture in improving cough and nasal reflux (to the throat) in AR patients.

OBJECTIVETo explore the transverse relaxation rate with gradient echo R2(*) changes in patients with Parkinsonian variant of multiple system atrophy (MSA-P) with a voxel-based analysis of R2(*) map.

METHODSWhole brain structural images and multi-echo T2(*) weighted image were acquired in 27 patients with probable MSA-P and 24 healthy individuals. R2(*) maps of the MSA-P were compared with the controls by voxel-based methods.

RESULTCompared with the controls, MSA-P patients showed significant R2(*) decrease bilaterally in brain stem, cerebellar hemispheres, insular lobe, temporal lobes, caudate nucleus, and corpus callosum (P<0.005).

CONCLUSIONSR2(*) can reveal the significant brain involvements of MSA-P. The introduction of gradient echo may increase the sensitivity, although the susceptible artifact may interfere the detection efficiency of R2(*).

Adult ; Case-Control Studies ; Female ; Humans ; Image Processing, Computer-Assisted ; methods ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Multiple System Atrophy ; diagnosis ; Sensitivity and Specificity

OBJECTIVETo describe the incidence and mortality rates of esophageal cancer from 1974-2002 in Cixian county of Hebei province. Basic information on comparative geographical, epidemiological, and clinical research was collected.

METHODSIn early 1970s, cancer registry system in Cixian was established, collecting information on all the esophageal cancer cases in Cixian. Data was checked manually, then computerized, coded and analyzed using the software--SPSS 11.5.

RESULTSFrom 1974 to 2002, there were 18 471 esophageal cancer cases in Cixian, with 11 068 males and 7403 females, respectively. The age standardized incidence rate (ASR) for males was 208.77 per 100,000, while 120.47 per 100,000 for females. The trend of incidence rate of esophageal cancer had decreased during the 29 years from 1974 to 2002 (trend chi(2) = 19.94, P < 0.001). From 25 years of age onward, the incidence rates of the lower age groups declined with the increase of age. As for geographic distribution, the incidence rate in mountainous areas and hilly areas showed a significant declining trend in mountainous areas, chi(2) = 195.00, P < 0.001; hilly areas, chi(2) = 46.08, P < 0.001. The esophageal cancer incidence in plain areas remained steady, but had a slight increase in recent years. From 1969 to 2002, there were 18,736 cases died of esophageal cancer with 11 598 males and 7138 females. The ASR for male was 127.17 per 100,000 and 101.57 per 100,000 for female. Compared with the year 1969, the mortality rate of esophageal cancer in 2002 had a 37.96% decline. The proportion of esophageal cancer among malignant tumors in different decades decreased significantly.

CONCLUSIONThe trend of the incidence rate of esophageal cancer had been decreasing for the last 29 years. The incidence rate in mountainous areas and hilly areas showed a declining trend while in the plain areas it remained steady but having slight increase in the recent years. The mortality rate of esophageal cancer had a significant decrease from 1969 to 2002.

Adult ; Age Factors ; China ; epidemiology ; Esophageal Neoplasms ; epidemiology ; mortality ; Female ; Humans ; Incidence ; Male ; Registries ; Software

OBJECTIVETo explore the toxic effect of fluoride on the human thyroid cells (Nthy-ori 3-1) and its mechanism.

METHODSNthy-ori 3-1 cells were exposed to 0.0, 0.1, 1.0, 3.0 mmol/L of sodium fluoride (NaF) in vitro. After 24 hours incubation, 3 (4,5-Dimethylthiazol-z-yl)-3, 5-diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) assay were used to measure cell viability and the LDH leakage rate. Reactive oxygen species (ROS) level, constituent ratio of the cell cycle, and apoptosis rate were measured by flow cytometry.

RESULTSComparing to viability of control group (set as 100.00%), the cell viability of the 1.0, 3.0 mmol/L fluoride-treated groups (76.64 +/- 9.13)%, (64.04 +/- 6.32)% were significantly decreased (all P values <0.01). LDH leakage rate and ROS level of the 3.0 mmol/L fluoride-treated group ((48.66 +/-7.15)%, (29993.50 +/- 1786. 86) FI) were significantly increased (all P values <0.01) compared to control group ((35.24 +/- 3.02)%, (13021.33 +/- 1067.55) FI). The G0/G1 phase cells of the 1.0 mmol/L fluoride-treated group ((40.76 +/- 5.65)%) were lower than control group (60.09 +/- 1.76)% (P < 0.01), yet the percentage of cells in S phase ((54.05 +/- 4.59)%) were higher than the control group (32.59 +/- 2.43) % (P < 0.01). Comparing to control group ((9.64 +/- 3.44)%), the percentage of apoptosis cells increased in the 3.0 mmol/L fluoride-treated group ((20.09 +/- 3.22)%) (P < 0.01).

CONCLUSIONTo Nthy-ori 3-1 cells, fluoride under experimental concentrations decreases cell viability, improve the LDH leakage rate, and ROS level. It blocks the cells in S phase and induce cell apoptosis.

Apoptosis ; drug effects ; Cell Cycle ; Cell Division ; Cell Line ; Fluorides ; toxicity ; Humans ; Reactive Oxygen Species ; analysis ; Thyroid Gland ; cytology ; drug effects

BACKGROUNDA patented remote controlled capsule (RCC) has recently been developed to provide noninvasive drug delivery to selected sites in the human gut that allows assessment of regional gastrointestinal (GI) drug absorption under a normal physiological environment. The objective of this study was to investigate the rate and extent of aminophylline absorption after site-specific delivery of the drug in the GI tract using RCC and a magnetic marker monitoring (MMM) technique.

METHODSThis study was conducted in twelve healthy male subjects, in a three-treatment, randomized, crossover manner with a 7-day washout. Eligible subjects received a 150 mg aminophylline dose through an oral administration, or via a remote controlled capsule, delivered to the small bowel or ascending colon. MMM was employed to monitor the GI transit of the RCC, and the radio-frequency signal was used to activate capsules at target sites. Blood samples were obtained at regular intervals until 24 hours post dose/activation. Plasma theophylline concentrations were measured by a TDx System Analyzer. A comparison of the PK profile with the oral dosing route of aminophylline was performed after delivery to the small bowel and colon.

RESULTSThe RCC was well tolerated in volunteers. The mean capsule activation time for the small bowel and ascending colon was 2.07 hours and 6.08 hours post dose. Aminophylline had similar absorption profiles from the small bowel compared with the stomach, with an area under the curve (AUC(t)) ratio of 92% vs. the stomach, but a lower absorption profile from the ascending colon, with an AUC(t) ratio of 47.2% vs. the stomach.

CONCLUSIONSThe proprietary of the RCC and MMM technique offer the opportunity to obtain data on the intestinal absorption of a drug in humans under noninvasive conditions. Aminophylline is rapidly and efficiently absorbed from the small bowel. While colonic absorption was limited by the poor water condition although effective absorption was observed from the ascending colon. This provides an opportunity for rational development of modified-release formulations as well as alternative dosage forms.

Adult ; Aminophylline ; administration & dosage ; pharmacokinetics ; Capsules ; administration & dosage ; pharmacokinetics ; Colon ; metabolism ; Humans ; Intestine, Small ; metabolism ; Male ; Young Adult