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Biomedical subjects

Z Tang

Publications and source records attributed to Z Tang.

At least 37 records · Page 2Linked to original sources

Changes in the inferior alveolar nerve after mandibular lengthening with different rates of distraction.

PURPOSE: This study investigated the changes in the inferior alveolar nerve after mandibular lengthening with different rates of distraction. MATERIALS AND METHODS: Bilateral mandibular corticotomies were performed in 8 goats. The mandibles in 6 goats were lengthened 10 mm using a custom-made distractor with 2 different rates of distraction (1 mm/d [n = 3] and 2 mm/d [n = 3]); the other 2 nondistracted mandibles served as a control. The goats with distracted mandibles were killed at 2 weeks after completion of distraction. The inferior alveolar nerve specimens from all animals were harvested and processed for histologic and ultrastructural evaluation. RESULTS: The mandibles were lengthened successfully in the distracted animals. Morphologic changes in the inferior alveolar nerves were observed when compared with the nondistracted controls. Moreover, signs of nerve degeneration, such as demyelination, axonal swelling, axoplasmic darking, and decrease in the number of axons, were more extensive and prominent in those nerves distracted at a rate of 2 mm/d. CONCLUSIONS: Degenerative changes in the inferior alveolar nerve occur after mandibular lengthening by distraction osteogenesis. The distraction rate of 1 mm/d appears to be tolerable and safe for the inferior alveolar nerve, but rapid distraction may cause serious degeneration.

Animals↗

APC2 Cullin protein and APC11 RING protein comprise the minimal ubiquitin ligase module of the anaphase-promoting complex.

In mitosis, the anaphase-promoting complex (APC) regulates the onset of sister-chromatid separation and exit from mitosis by mediating the ubiquitination and degradation of the securin protein and mitotic cyclins. With the use of a baculoviral expression system, we have reconstituted the ubiquitin ligase activity of human APC. In combination with Ubc4 or UbcH10, a heterodimeric complex of APC2 and APC11 is sufficient to catalyze the ubiquitination of human securin and cyclin B1. However, the minimal APC2/11 ubiquitin ligase module does not possess substrate specificity, because it also ubiquitinates the destruction box deletion mutants of securin and cyclin B1. Both APC11 and UbcH10 bind to the C-terminal cullin homology domain of APC2, whereas Ubc4 interacts with APC11 directly. Zn(2+)-binding and mutagenesis experiments indicate that APC11 binds Zn(2+) at a 1:3 M ratio. Unlike the two Zn(2+) ions of the canonical RING-finger motif, the third Zn(2+) ion of APC11 is not essential for its ligase activity. Surprisingly, with Ubc4 as the E2 enzyme, Zn(2+) ions alone are sufficient to catalyze the ubiquitination of cyclin B1. Therefore, the Zn(2+) ions of the RING finger family of ubiquitin ligases may be directly involved in catalysis.

Amino Acid Sequence↗

Single nucleotide polymorphisms (SNPs) assay using reversible association and dispersion of DNA-linked colloidal nanoparticles.

The amphiphilic copolymer consisting of oligodeoxyribonucleotide (ODN; dT12) as the hydrophilic part and thermo-responsive poly(N-isopropylacrylamide) (polyNIPAAm) as the hydrophobic part was prepared. The copolymers formed DNA-linked colloidal nanoparticles above the phase transition temperature of polyNIPAAm part. The nanoparticles aggregated rapidly when the complementary ODN (dA12) was added into the dispersion. In contrast, they kept dispersed in the absence of the complementary ODN and in the presence of the point-mutated ODN ((dA6)dT(dA5)). These distinct phenomena may be applied for an oligonucleotides discrimination system in gene diagnosis.

Acrylic Resins↗

Oxygen effects on glucose meter measurements with glucose dehydrogenase- and oxidase-based test strips for point-of-care testing.

OBJECTIVES: To determine the effects of different oxygen tensions (Po2) on glucose measurements with glucose dehydrogenase (GD)-based and glucose oxidase (GO)-based test strips, to quantitate changes in glucose measurements observed with different Po2 levels, and to discuss the potential risks of oxygen-derived glucose errors in critical care. DESIGN: Venous blood from healthy volunteers was tonometered to create different oxygen tensions simulating patient arterial Po2 levels. Venous blood from diabetic patients was exposed to air to alter oxygen tensions simulating changes in Po2 during sample handling. Whole-blood glucose measurements obtained from these samples with six glucose meters were compared with reference analyzer plasma glucose measurements. Glucose differences were plotted vs. different Po2 levels to identify error trends. Error tolerances were as follows: a) within +/-15 mg/dL of the reference measurement for glucose levels 100 mg/dL. SETTING AND SUBJECTS: Five healthy volunteers in the bench study and 11 diabetic patients in the clinical study. RESULTS: In the bench study, increases in Po2 levels decreased glucose measured with GO-based amperometric test strips, mainly at Po2 levels >100 torr. At nearly constant glucose concentrations, glucose meter systems showed large variations at low (39 torr) vs. high (396 torr) Po2 levels. Glucose measured with GD-based amperometric and GO-based photometric test strips generally were within error tolerances. In the clinical study, 31.6% (Precision PCx), 20.2% (Precision QID), and 23.0% (Glucometer Elite) of glucose measurements with GO-based amperometric test strips, 14.3% (SureStep) of glucose measurements with GO-based photometric test strips, and 4.6% (Accu-Chek Advantage H) and 5.9% (Accu-Chek Comfort Curve) of glucose measurements with GD-based amperometric test strips were out of the error tolerances. CONCLUSIONS: Different oxygen tensions do not significantly affect glucose measured with the GD-based amperometric test strips, and have minimal effect on GO-based photometric test strips. Increases in oxygen tension lowered glucose measured with GO-based amperometric test strips. We recommend that the effects of different oxygen tensions in blood samples on glucose measurements be minimized by using oxygen-independent test strips for point-of-care glucose testing in critically ill and other patients with high or unpredictable blood Po2 levels.

Blood Gas Analysis↗

Homeodomain leucine zipper proteins bind to the phosphate response domain of the soybean VspB tripartite promoter.

The soybean (Glycine max L. Merr. cv Williams 82) genes VspA and VspB encode vacuolar glycoprotein acid phosphatases that serve as vegetative storage proteins during seed fill and early stages of seedling growth. VspB expression is activated by jasmonates (JAs) and sugars and down-regulated by phosphate and auxin. Previous promoter studies demonstrated that VspB promoter sequences between -585 and -535 mediated responses to JA, and sequences between -535 and -401 mediated responses to sugars, phosphate, and auxin. In this study, the response domains were further delineated using transient expression of VspB promoter-beta-glucuronidase constructs in tobacco protoplasts. Sequences between -536 and -484 were identified as important for phosphate responses, whereas the region from -486 to -427 mediated sugar responses. Gel-shift and deoxyribonuclease-I footprinting assays revealed four DNA-binding sites between -611 and -451 of the soybean VspB promoter: one in the JA response domain, two in the phosphate response domain, and one binding site in the sugar response domain. The sequence CATTAATTAG present in the phosphate response domain binds soybean homeodomain leucine zipper proteins, suggesting a role for these transcription factors in phosphate-modulated gene expression.

Acid Phosphatase↗

Ultrasensitive optical DNA biosensor based on surface immobilization of molecular beacon by a bridge structure.

A novel biotinylated molecular beacon (MB) probe was developed to prepare a DNA biosensor using a bridge structure. MB was biotinylated at the quencher side of the stem and linked on a biotinylated glass cover slip through streptavidin, which acted as a bridge between MB and glass matrix. An efficient fluorescence microscope system was constructed to detect the fluorescence change caused by the conformation change of MB in the presence of complementary DNA target. The proposed biosensor was used to directly detect, in real-time, the target DNA molecules. The bridge immobilization method caused the proposed DNA biosensor to have a faster and more stable response. Under the optimal conditions, the newly developed DNA biosensor showed a linear response toward ssDNA in the range of 5-100 nM with a detection limit of 2 nM. It was interesting to note that the described biosensor was reproducible after being regenerated by urea.

Biosensing Techniques↗

Comparison of in vivo dopamine D2 receptor binding of [(123)I]AIBZM and [(123)I]IBZM in rat brain.

[(123)I]AIBZM, (S)-5-[(123)I]-Iodo-N-[(1-ethyl-2-pyrrolidinyl)]methyl-4-amine-2-methoxybenzamide is a derivative with high affinity for the D2 receptor. Labeling was achieved by the Iodogen method. The in vivo affinity for the D2 receptor and the biological characteristics were performed in rats. The brain uptake of [(123)I]AIBZM was significantly lower, however the striatum/cerebellum ratio (2h p.i.) was higher than that of [(123)I]IBZM. Because of the high affinity and its possibly lower unspecific binding compared to [(123)I]IBZM, [(123)I]AIBZM may be a potential imaging agent for the D2 dopamine receptor.

Animals↗

[Study of the cytotoxity against human hepatocellular carcinoma cells induced by the MAGE-1 gene modified dendritic cells].

OBJECTIVE: To genetically modify dendritic cells (DC) with a tumor associated antigen gene MAGE-1 and to observe in vitro the cytotoxic effect induced by this genetically modified DC against human hepatocellular carcinoma (HCC) cell line SMMC7721, thus giving a primary verification of the possibility of this genetically modified DC to induce specific antitumor immunity against HCC and serving as a new type of vaccine. METHODS: The MAGE-1 gene was inserted into the retrovirus vector LXSN to construct the recombinant retrovirus LMSN. The monocyte-derived DCs were transfected by LMSN and control virus LXSN respectively as well as a third group was set up as non-transfected control. The MAGE-1 gene expression in LMSN transfected DC was identified by Western blot and the in vitro cytotoxities against SMMC7721 induced by three groups of DC were tested by MTT assay. RESULTS: A recombinant retrovirus LMSN containing the tumor rejection antigen gene MAGE-1 was successfully constructed and the MAGE-1 gene expression in LMSN transfected human monocyte-derived DC was induced. The LMSN transfected DC could induce very high lytic activity against SMMC7721 in vitro with the lytic activity of 78.9%+/-3.6%. Nevertheless, the LXSN transfected DC and non-transfected DC only induced relatively lower lytic activity as 34.7%+/-4.3% and 3.9%+/-2.0%, respectively. The difference of the lytic activities between those three groups as statistically significant (P<0.01). CONCLUSIONS: The MAGE-1 gene transfected DC can induce higher in vitro cytotoxicity against SMMC7721, suggesting the possibility of this genetically modified DC to induce specific antitumor activity and to serve as a new type of vaccine for HCC.

Animals↗

[Effects of interferon-alpha on recurrence and metastasis of hepatocellular carcinoma after curative resection in nude mice].

OBJECTIVE: To study the effect of interferon-alpha (IFN-alpha) on the recurrence and metastasis of hepatocellular carcinoma (HCC) in nude mice, and to clarify if there is synergistic effect treated by combination of IFN-alpha and all-trans retinoic acid (ATRA). METHODS: The effect of IFN-alpha and/or ATRA on the proliferation of HCC cell lines was measured in vitro. The metastatic model of human HCC in nude mice LCI-D20 was used in present study. Curative resection was performed at 10th day after implantation in 44 nude mice. Drugs were given at the next day after resection. IFN-alpha was administered subcutaneously at doses of 3+/-10(5) U/day, 6+/-10(5) U/day, respectively. ATRA was administered p.o. at a dose of 20 mg/kg/day, and IFN-alpha 6+/-10(5)U/day combined with ATRA 20 mg/kg/day. The mice were sacrificed 35 days after treatment. The recurrent tumor size was measured and the presence of intrahepatic dissemination and lung metastases were recorded. RESULTS: The effect of IFN-alpha and/or ATRA on the proliferation of HCC cells SMMC7721, BEL-7402, BEL-7405, and MHCC97 was not obvious. The combination of IFN-alpha and ATRA had no synergistic effect in vitro. The lung metastatic rate, the liver recurrent rate, the size of main recurrent lesions, the number of intrahepatic disseminating nodules and the largest disseminating nodule of the controlled group was 100%(12/12), 100%(12/12), (1346.3+/-4.2 ) mm(3), 8.2+/-4.4, 864 mm(3), respectively; whereas it was 0, 87.5%(7/8), (8.7+/-2.9) mm(3), 2.3+/-0.6, and 7.8mm(3), respectively in the IFN-alpha 3+/-10(5) U/day treated group(P<0.05); 0, 12.5%(1/8), 0.5mm(3), 2, 0.5 mm(3) in the IFN-alpha 6+/-10(5)U/day treated group(P<0.05); 0, 12.5%(1/8), 1 mm(3), 2.5+/-0.7, 8 mm(3) in the IFN-alpha 3+/-10(5) U/day and ATRA treated group(P<0.05); 87.5%, 100%, (1472.6+/-5.6) mm(3), 7.3+/-3.8, 768.5 mm(3) in the ATRA treated group (P>0.05). CONCLUSIONS: IFN-alpha has an inhibitory effect on intrahepatic recurrence and lung metastasis of human HCC after curative resection in nude mice, and the effect is enhanced with increasing dose. IFN-alpha and ATRA have no synergistic effect according to in vivo and in vitro test. ATRA has no effect on recurrence and metastasis of HCC.

Animals↗

[Relationship between serum matrix metalloproteinase-2 and metastasis and recurrence following radical hepatic resection in hepatocellular carcinoma].

OBJECTIVE: To study the relationship between serum matrix metalloproteinase-2 (MMP-2) and metastasis and recurrence following radical hepatic resection in hepatocellular carcinoma (HCC). METHODS: Cox's proportional hazard model was used to determine the significant clinical factor of prognosis. Meanwhile, enzyme linked immunoadsordent assay (ELISA) and northern blot analysis were adopted to detect serum and tumor tissue levels of MMP-2 respectively in HCC patients. RESULTS: Cox's proportional hazard model showed that tumor size and tumor number were significant prognostic factors of HCC patients following hepatic resection (P=0.022 and P=0.040). According to this result, we divided HCC patients into high-tendency to metastasis recurrence and low-tendency to metastasis recurrence groups. Serum levels of MMP-2 in high-tendency to metastasis recurrence following radical hepatic resection group were significantly higher than those in low-tendency group (26.39ng/m+/-2.64ng/ml vs 24.86ng+/-1.95ng/ml, P<0.05). Serum levels of MMP-2 in HCC patients performed non-radical hepatic resection group were also significantly higher than those in HCC patients performed radical hepatic resection group (29.43ng+/-3.12 ng/ml vs 25.72ng+/-2.45ng/ml, P<0.01). Northern blot analysis revealed that the changes of MMP-2 level in the serum were consistent with those of its mRNA level in the tumor tissue of HCC patients. CONCLUSIONS: Serum MMP-2 level is an indicator for metastatic recurrence following radical hepatic resection in HCC. The high levels of MMP-2 in the serum are due to high MMP-2 mRNA expression in the tumor tissue of HCC patients.

Carcinoma, Hepatocellular↗

[Combined gene therapy for murine liver cancer with interleukin-18 and cytosine deaminase genes].

OBJECTIVE: To investigate the synergistic antitumor effects of murine IL-18 and CD/5FC gene therapy on mice bearing liver cancer. METHODS: A retrovirus vector pGCEN/IL-18 containing murine interleukin-18 gene was constructed. The retrovirus carrying IL-18 gene was used to infect murine liver cancer cell MM45T.Li, and proved to secret biological active IL-18. In mice bearing liver cancer, (60)Co-irradiated MM45T.Li/IL-18 vaccine was inoculated subcutaneously once a week for two weeks, and/or AdCD was injected intratumorally with 5FC injected i.p. for 8 days. RESULTS: Thirty days from the treatment, the tumor volume of control group was 1580 approximately 1625 mm(3), MM45T.Li/IL-18 vaccine group was 366 +/- 159 mm(3), AdCD/5FC group was 438 +/- 65 mm(3), and combined IL-18 and AdCD/ 5FC therapy group was 15 +/- 7 mm(3) (P<0.05). The tumor volume in single gene therapy group reduced to the smallest after three-week treatment, but grew large again, while the tumor volume in combined therapy group still remained small. The median survival time in control group was 50.0 approximately 51.5 days, MM45T.Li/IL-18 group was 65 days, AdCD/5FC group was 57 days versus 75 days for combined gene therapy group (P<0.05), and with more abundant infiltration of CD4+ and CD8+ lymphocytes around the tumor in combined gene therapy group. CONCLUSIONS: Combined gene therapy with IL-18 and CD/5FC can reduce the tumor volume and elicit the antitumor immunity of the host, which is superior to the single gene therapy for murine liver cancer.

Animals↗

The clinical and pathological characteristics of Chinese patients with pauci-immune crescent glomerulonephritis.

OBJECTIVE: To investigate the clinical and pathological characteristics of pauci-immune crescent glomerulonephritis (PICGN) in Chinese patients. METHODS: During 13 years (1985-1998), 6400 patients underwent non-transplanting renal biopsy. Twenty-four patients were diagnosed as PICGN. All clinical and laboratory data of these patients were collected from the patients' records and used for detailed analysis. The diagnosis is based on clinicopathologic findings. RESULTS: Of the 24 patients, 16 were females and 8 were males, with median age of 33 years (ranged 10-76 years). Microscopic polyarteritis (MPA) (33.3%) and systemic vasculitis (8.3%) were the secondary diseases. The incidence of PICGN was 0.38% in renal biopsies and 22.9% in crescentic glomerulonephritis. Clinically, most patients (75.0%) showed rapidly progressive nephritis with enlarged kidneys. At onset, gross hematuria was noted in 58.3% of patients, hypertension in 45.8%, nephrotic syndrome in 41.7%, and oliguria in 25.0%. However, systemic symptoms were rare except for anemia. Pathologically, necrosis of glomerular capillaries (62.5%), infiltration of monocytes and neutrophil cells in glomeruli (66.7%), and vasculitis in the interstitium (53.3%) were observed. In addition, glomerulosclerosis was noted in 45.8%, severe tubular atrophy in 83.3% and interstitial fibrosis in 75.0%. Anti-neutrophil cytoplasmic antibodies (ANCAs) were positive in 52.2%. All patients except two received intensively immunosuppressive therapy. Sixteen patients were available for long-term follow up (median 29.8 months, range 8-92 months). Twelve of them had life-sustaining renal function, four had normal serum creatinine (< 124 mumol/L) and only 4 patients were dialysis-dependent. CONCLUSION: PICGN is not rare in China. Early diagnosis and administration of immunosuppressive therapy, particularly in patients with rapidly progressive glomerulonephritis (RPGN), are important for good prognosis.

Adolescent↗

The distribution and significance of renal infiltrating cells in patients with diffuse crescentic glomerulonephritis.

OBJECTIVE: To study the significance and distribution of renal infiltrating cells, including monocytes (CD68+ cells), proliferative cell nuclear antigen positive cells (PCNA+ cells), CD4+ and CD8+ cells in diffuse crescent glomerulonephritis (DCGN). METHODS: Fifty-six patients with DCGN were studied, including 10 cases of anti-glomerular basement membrane (GBM)--type I DCGN, 26 immune complex--type II DCGN, and 20 cases of pauci-immune--type III DCGN. Glomerular and interstitial infiltrates of CD68+ and PCNA+ cells, and interstitial infiltrates of CD4+ and CD8+ cells were detected by using four-layer PAP methods. RESULTS: There was a significant increase of renal infiltrating CD68+, PCNA+, CD4+ and CD8+ cells in patients with DCGN compared with that in normal controls. In patients with type I DCGN, there was a higher number of renal infiltrating CD68+ and PCNA+ cells than that in patients with type II and III DCGN. A glomerular infiltrates of CD68+ and PCNA+ cells correlated with the interstitial infiltrates of CD4+ cells in type I or III DCGN patients. In lupus DCGN patients, the numbers of renal infiltrating CD68+ and PCNA+ cells were similar to vasculitis or type III DCGN patients. CONCLUSION: These findings demonstrate that the renal infiltrates of CD68+ and PCNA+ cells play an important role in patients with DCGN, that the infiltrates of CD4+ cells correlate with the infiltrates of CD68+ and PCNA+ cells may be an active marker of DCGN, and that cell-mediated immunity may contribute to crescent formation in lupus DCGN patients.

Adolescent↗

Cyclosporin A treatment for idiopathic membranous nephropathy.

OBJECTIVE: To evaluate the efficacy of cyclosporin A (CSA) in the treatment of idiopathic membranous nephropathy (IMN), a prospective controlled clinical study was performed. METHODS: This study included a group of 30 IMN patients, among them 15 were treated with CSA and 15 with captopril (CAP). The diagnosis of IMN was made with exclusion of secondary forms of membranous nephropathy by extensive clinical and pathological studies. No patients received steroids or cytotoxic agents for six months prior to enrollment. In the CSA group, CSA was given at an initial dosage of 5 mg.kg-1.d-1, gradually tailed off over the first three months and maintained at 2 mg.kg-1.d-1 for 12 months. In the CAP group, CAP was given at a dosage of 37.5 mg/day. RESULTS: In the first three months, 6 (6/15) complete remissions (CR) and 2 (2/15) partial remissions (PR) were observed in the CSA group while only 2 (2/15) PRs were observed in the CAP group. Before the end of the 15-months, 8 patients in the CSA group experienced CR and 4 patients experienced PR. One CR patient relapsed as the dosage of CSA was reduced, so 7 patients remained in CR at the end of the first 15-months. No additional CR or PR was observed in the CAP group during late follow-up. At the last visit (an average follow-up time of 44 months) in the CSA-group, another 2 CR patients had relapsed and 1 CR patient shifted to PR after stopping the CSA treatment, so 4 CR and 5 PR remained in the CSA group. In the CAP group, 3 spontaneous CRs occurred beyond 1.5 year's follow-up, with 3 CR and 2 PR at the last visit. No difference was found between the averages of the initial and the last serum creatinine levels in either group. No serious adverse effects were found during CSA treatment. Re-biopsy data of three patients responsive to CSA treatment showed that no pathological improvement of glomerular basement membrane was observed, even in cases at remission. Tubulointerstitial fibrosis was found in 1 relapsed CR patient, whose serum creatinine increased above the normal range, but not in the other 2 patients whose serum creatinine remained in the normal range. CONCLUSIONS: CSA therapy at a dosage of 5 mg.kg-1.d-1 is effective in inducing remission of nephrotic syndrome in adult IMN patients within three months, with a response rate of 80%. A relatively high rate of relapse (50%) was observed within 2 years after the withdrawal of CSA treatment.

Adult↗

[Clinical and radiographic evaluation of 108 dental implants after 1-year loading].

OBJECTIVE: To evaluate the clinical outcomes and a possible correlation between peri-implant mucosal inflammation and marginal bone loss in a group of Chinese patients who received IMZ and Frialit-2 implants one year after restoration. METHODS: The clinical and radiography parameters of 108 IMZ and Frialit-2 dental implants in 70 patients were measured. RESULTS: There were no signs of mobility and peri-implant radiolucencies in any of the implants. The average bone loss adjacent to implants was (0.63 +/- 0.78) mm. The prevalence of peri-implant mucosal inflammation, as indicated by suclus bleeding index (SBI) of 1.0 or more, was 32.9%. Significant correlation was found between mucosal inflammation and bone loss. The severely inflamed sites experienced greater bone loss than that of healthy or slightly inflamed sites (P < 0.05). In 92% of sites, plaque index (PLI) of more than 1 was measured on implant surfaces. The periodontal status of the remaining natural teeth in each subject was evaluated using the community periodontal index of treatment need (CPITN). Of the 70 examined patients, 15 patients needed oral hygiene instruction, 44 needed scaling and root planing, 8 patients needed periodontal surgical therapy, and only 3 did not need any periodontal treatment. CONCLUSIONS: The 1-year outcomes from this patient series indicated that IMZ and Frialit-2 implant provide satisfactory clinical results. One of the etiologic factors of alveolar bone loss around implants seems to be plaque-associated marginal inflammation. Improvement of oral hygiene, elimination of marginal tissue inflammation, and proper treatment of periodontal disease of natural teeth are needed for maintaining the implants in these observed subjects.

Adolescent↗

[Clinical study on preventing endodontic interappointment pain with dexamethasone].

OBJECTIVE: To investigate the effect decreasing of the incidence of endodontic interappointment pain(EIP) by local injection of 5 mg dexamethasone. METHODS: 5 mg dexamethasone was injected submucosally at apical region of 80 teeth with asymtomatic pulp necrosis after root canal therapy, then observing the incidence of EIP and compared with control group. RESULTS: The clinical observation revealed that the incidence of EIP of dexamethasone group (10.00%) was lower than that of control group (33.75%), P < 0.01, and the level of pain was decreased. Ordinal logistic regression revealed that EIP was related to tooth location, fistula, and root canal therapy. CONCLUSION: The incidence of EIP can be reduced after 5 mg dexamethasone local injected.

Adult↗

[Mechanism of contour hedgerow's control for non-point pollution in the semiarid region in northwest Hebei Province].

Slope nutrient loss is an important type of non-point pollution. The mechanism of non-point pollution control by using plenty of natural observed data in Hilly Loess region in Northwest Hebei Province, as well as combating with the large-scale artificial simulation rainfall in the field slope was analyzed. The study results show that the critical slope length was 10-15 m on the condition of rainstorm, which led to the generation of rill and made the erosion amount went up obviously. The study show that the nutrient loss in sediment was the main type of non-point pollution, the contour hedgerow the process of non-point pollution by controlling the nutrient loss in sediment, then the study got the erosion control model of the contour hedgerow.

China↗

Changes in the temporomandibular joint after mandibular lengthening with different rates of distraction.

This study assessed the changes in the condyle after mandibular lengthening with 2 different rates of distraction (1 mm/day and 2 mm/day). Unilateral mandibular distraction was performed in 8 young adult goats. The animals were sacrificed 8 weeks after the completion of distraction, and the temporomandibular joint (TMJ) specimens were harvested and processed for histologic examination and histomorphometric analysis. Adaptive changes in the condyle were observed in the goats distracted at a rate of 1 mm/day, whereas degenerative alterations were found in those distracted at a rate of 2 mm/day. This study suggests that the TMJ is able to withstand the impact of distraction at a rate of 1 mm/day, but more rapid distraction may induce degeneration in the condylar cartilage.

Animals↗