Biomedical subjects

S Zhou

Publications and source records attributed to S Zhou.

At least 181 records · Page 10Linked to original sources

PubMed2000

[Occlusal contact force and stress analysis of molars with vertical root split].

OBJECTIVE: To study the induction of vertical root split by occlusal force. METHODS: 1. The occlusal contact force was studied in 34 cases (39 teeth) by photocclusion. 2. The stress analysis for the first mandicular molar was studied by three-dimensional definite element. RESULTS: 1. The occlusal contact force didn't distribute balancedly in 26 cases (31 teeth) and the suffering teeth bore greater force. 2. The bucco-lingual central line of the mesial root canal wall underwent greater tensile stress when tooth bore load with 30 degrees angle to axis, or buccal-lingual lateral load or logitudinal occlusive load on the masial or distal cusp. CONCLUSION: The vertical root split of molar is associated with greater occlusal force and the stress that concentrated on the buccolingual central line of the mesial root wall for a long time.

Adult↗

PubMed2000

[To probe into the practicability of using the jaw position of eliminating TMJ clicks as the therapeutic position of repositioning splint].

OBJECTIVE: To evaluate that it was practicable to use the jaw position of eliminating TMJ clicks as the therapeutic position of repositioning splint and to probe into the therapeutic mechanism of repositioning splint. METHODS: 25 patients with reducible disc displacement were treated with repositioning splint. The therapeutic jaw position was the position without TMJ clicking, then verified by Arthrography. The treatment effect was observed. RESULTS: Among 25 cases, 19 discs were completely recaptured, 5 incompletely recaptured, 1 not recaptured. Once the splints inserted, the movements of disc-condyle complex were smooth. After treatment finished, the opening types were improved, the clicks were lessened. CONCLUSIONS: It's practicable to use the jaw position of eliminating clicks as the treatment jaw position of repositioning splint. The therapeutic mechanism of repositioning splint may be that it altered the relationship of disc and condyle and improved their movement. That was favorable to fibrize the retrodiscal tissue and to strengthen the posterior band of disc.

Adolescent↗

PubMed2000

[The effects of local stress on bone mass of mandibles in ovariectomized rats].

OBJECTIVE: To observe the relationship between the change of stress environment of mandibles and their bone mass in normal and ovariectomized(OVX) rats. METHODS: The high and low stress environment models of mandibles were established by unilateral maxillary molars extraction. The masticatory sides of the mandibles were regarded as the high stress sides and the non-masticatory sides were regarded as the low stress sides. Ovariectomized rats were utilized as postmenopausal osteoporosis models and Sham-ovariectomized(Sham-OVX) rats as control group. According to these ideas, 48 female rats were divided into 4 groups: 1) OVX + extraction group; 2) OVX + non-extraction group; 3) Sham-OVX + extraction group; 4) Sham-OVX + non-extraction group. The bone mineral densities (BMD) of all mandibles were measured by single-photon absorptiometry bilaterally 1.5 months and 3 months after extraction. RESULTS: The mandibles of ovariectomized rats had lower BMD than those of normal rats(P < 0.05). To normal rats, the BMD of mandibles in low stress sides were lower than the high stress sides 3 months after extraction(P < 0.05), but the BMD of the two sides were not significantly different to those of the non-extraction control ones(P > 0.05). To ovariectomized rats, the BMD of mandibles low stress sides were much lower than the high stress sides(P < 0.01). The BMD of mandibles in low stress sides were much lower than non-extraction ones of OVX group after 3 months(P < 0.05). The BMD of the high stress sides were much higher than those of the non-extraction control ones of OVX group(P < 0.05), but they were still lower than those of the non-extraction control ones of Sham-OVX group(P < 0.05). CONCLUSION: The results indicate that the masticatory functions(the high stress environment) tend to conserve the mandibular bone mass in patients with systemic osteopenia such as postmenopausal osteoporosis and the masticatory deficiency (the low stress environment) tends to aggravate mandibular bone loss induced by systemic osteopenia. The masticatory functions should be rehabilitated for these patients as early as possible.

Animals↗

PubMed2000

[Clinical study of Astragalus injection plus ligustrazine in protecting myocardial ischemia reperfusion injury].

OBJECTIVE: To investigate the mechanism of Astragalus injection plus ligustrazine in preventing the occurrence of myocardial ischemia reperfusion injury (MIRI) during open heart surgery of cardiopulmonary bypass, and the treating principle of MIRI in TCM. METHODS: Twenty-four patients suffering from either valvular heart diseases or congenital ventricular septal defect were randomly divided into three treated groups (Astragalus, ligustrazine, Astragalus plus ligustrazine) and the control group, 6 in each group. Blood samples were taken via subclavian central vein at the time before anesthesia (T1), 10 minutes of occlusion of aorta (T2), 10 minutes (T3) and 30 minutes (T4) after the release, and the end of operation (about 180 minutes after release, T5) respectively; EKG was observed, and the levels of asparate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), MB isoenzyme of CK (CK-MB), malondialdehyde (MDA) and the activity of superoxide dismutase (SOD), nitric oxide (NO), nitric oxide synthetase (NOS) were determined. RESULTS: The treated groups could reduce the levels of AST, LDH, CK, CK-MB, MDA, SOD compared with the control group, particularly Astragalus plus ligustrazine, there had significant difference (P < 0.05, P < 0.01). In NO activity improvement, Astragalus plus ligustrazine won the best effect, Astragalus group the next. CONCLUSIONS: The mechanism of MIRI is Qi deficiency and blood stasis in TCM, its treating principles should be promoting Qi and removing the blood stasis. According to the authors' study, Astragalus plus ligustrazine could effectively protect against MIRI, which is better than using the 2 medicines separately.

Adolescent↗

PubMed2000

[Study on role of metallothionein in anticancer effect of copper green on treatment of experimental hepatocarcinoma in mice].

OBJECTIVE: To study the role of metallothionein (MT) in the anticancer effect of copper green on experimental hepatoma (H22) in mice. METHODS: Atomic absorbency spectrometry (AAS), silver saturation method and histochemistry method were used to study the content and distribution of copper and MT in liver and tumor tissues. RESULTS: (1) Both copper and MT contents in liver tissue of the copper treated group were significantly higher than that of the control group (P < 0.001 in both). (2) Copper content in tumor tissue of the treated group was higher whereas MT content was markedly lower than that of the control group (P < 0.001). (3) Histochemical examination showed that in the copper treated group, both copper and MT existed simultaneously in plasma and nuclei of liver cells, while in the tumor tissue, rich in copper but few or negative in MT existed. CONCLUSION: (1) In liver tissue, large amount of MT is coupled with copper which is helpful to protect liver from the damage of copper. (2) The decrease of MT in tissue of tumor could be beneficial for copper to exert full effect in killing tumor cell.

Animals↗

PubMed2000

[Distribution of calcitonin gene-related peptide-like immunoreactive fibres in the temporomandibular joint of rat].

OBJECTIVE: To observe the distribution of calcitonin gene-related peptide-like immunoreactive (CGRP-LI) nerve fibres in rat's temporomandibular joint (TMJ). METHODS: The avidin-biotin-peroxidase complex method and image analysis were employed to detect CGRP-LI nerve fibres in frozen sections of TMJs in eight rats. RESULTS: CGRP-LI nerve fibres were plentifully distributed in TMJs except the central disc band and bone, mainly in the periphery of blood vessels, especially arteries. Density: anterior disc attachment and capsule, (454.6 +/- 72.8) mm(2); posterior portion, (302.7 +/- 43.4) mm(2); lateral portion, (240.2 +/- 23.6) mm(2); medial portion, (229.6 +/- 25.0)mm(2); and peripheral portion of disc, (202.4 +/- 35.2) mm(2). CONCLUSION: CGRP-LI nerve fibres were widely distributed in rat TMJ and were a part of trigeminal sensory nerve. Density was highest in anterior disc attachment and capsule.

Animals↗

PubMed2000

[Compensation of external jugular vein to the reflux of cerebral blood after bilateral ligation of the internal jugular vein].

OBJECTIVE: To investigate the effects of conserving external jugular veins for compensating the back flow of intracranial veins. METHODS: The rhesus monkey was underwent bilateral radical neck dissection to simulate that performed in the human. In operation, the changes of intracranial pressure (ICP) after ligating these jugular veins was observed. RESULTS: The results indicate that ligation of the external and internal jugular veins will increase the ICP obviously, but conserving external jugular veins will reduce the increase of ICP and shorten the recovery time from increased ICP. CONCLUSIONS: The conservation of the external jugular veins will compensate the back flow of intracranial veins after RND. The experiment provides a simple and effective method for the prevention of intracranial complications and preservation of the flow of facial veins.

Animals↗

PubMed2000

[A clinical study on fresh amniotic membrane transplantation for treatment of severe ocular surface disorders at acute inflammatory and cicatricial stage].

OBJECTIVE: To investigate the safety and evaluate the effect of fresh amniotic membrane transplantation to reconstruct the ocular surface with severe inflammation and scarring. METHOD: Amniotic membrane transplantation (38 cases, 46 eyes), or combined with either limbal transplantation (9 cases, 9 eyes) or lamellar keratoplasty (8 cases, 8 eyes) was performed on ocular surface burns (5 cases, 6 eyes), recurrent Mooren's ulcer (8 cases, 8 eyes) and severe symblepharon (38 cases, 46 eyes). All the patients were followed-up for 6 - 18 months (mean, 11 months). Impression cytology was examined in 21 eyes with normal tear secretion post-operatively. RESULTS: No acute rejection was observed after fresh amniotic membrane transplantation. No progressive melt and perforation were seen in five out of six eyes with burns in reconstructed ocular surfaces. Neovascularization, pseudopterygium and iris atrophy were not found during the follow-up. Visual acuity was improved in various degrees. Corneal ulceration was not noted in 8 cases (8 eyes) with frequently recurrent Mooren's ulcer. Ocular surface reconstruction was successful in 46 of 49 eyes with severe symblepharon. Symblepharon occurred in the remaining three eyes but much less than pre-transplantation in degree. Amniotic epithelia have been examined in about three months on the transplanted eyes with normal tear secretion. CONCLUSION: Fresh amniotic membrane can be used as a graft to reconstruct ocular surface. Such transplantation can effectively reduce neovascularization, fibrosis and inflammation. Our data indicated that complete removal of pathological tissues and perfect fixation of amniotic membrane graft are crucial steps in the reconstruction of ocular surface.

Acute Disease↗

PubMed2000

[An epidemiology study on limb injuries in infants aged 0 - 14 years old in Tengzhou area during 1994 - 1998].

OBJECTIVE: To find out epidemiological features on limb injuries in infants. METHODS: Stratified random sampling was carried out to investigate limb injuries in children aged 0 - 14 years old in four villages and townships, Tengzhou city Shandong province from 1994 to 1998. RESULTS: Results showed that the total rate of limb injuried was 2.96% with a ratio of male/female 3.20:1. The injury on arms was higher than on legs. The first three leading rates of injuries were falling, hurt by sharp stuff and traffic accidents. The highest rate of injury took place from May to October during the year. The rate of limb injuried seemed to be increasing with a disabled rate of 115.97/100,000. CONCLUSION: Measures should be taken to reduce the rate of injuries, according to the epidemiological findings.

Accident Prevention↗

PubMed2000

[Study on the genetic difference of SEO type Hantaviruses].

OBJECTIVE: To understand the genetic type of Hantaviruses and the difference between them caused by rodents in Beijing and to furhter explore the source of the infectious factors. METHODS: Hantavirus RNA, isolated from lungs of rodents captured in Beijing and positive with Hantavirus antigens with frozen sectioning and Immunofluorescent assay, were reverse-transcribed and amplified with PCR with Hantavirus-specific primers. RESULTS: Five of the PCR amplifications were discovered and sequenced with 300 bp sequence data of M segments (from 2003 - 2302nt according cDNA of seoul 8039 strain). Nucleotide sequence homology showed that they were sequences of SEO-type Hantavirus. Compared with SEO type Hantavirus, the nucleotide sequence homology of these samples was more than 94% while the homology of amonia acid sequence was more than 98%. When compared with HNT type Hantavirus, the homology of nucleotide sequence became less than 72% with the homology of amonia acid sequence less than 81%. Similar to other Hantavirus of SEO type, their nucleotide sequences and deduced amino acid sequences were highly preserved. Phylogenetic tree analysis showed that the five viruses could be divided into at least 4 branches. CONCLUSION: It was quite likely that there were at least two sub-type SEO viruses with 4 branches that were circulating in Beijing.

DNA, Viral↗

PubMed2000

[Exploration of factors increasing transfer efficiency of retroviral mediated multidrug resistance gene (mdr1) into human CD(34)(+) cells].

OBJECTIVE: To explore factors influencing transfer of retroviral mediated multidrug resistance gene (mdr1) into human CD(34)(+) cells. METHODS: Transduction efficiency in the presence of different combinations of cytokines and human bone marrow stromal cells plus cytokines were determined by flow cytometry (FCM). Drug resistance was evaluated by plating yields of cultured hematopoietic progenitor cells. The effect of Taxol at different concentrations on mdr1 gene transfer cells was determined by FCM. RESULT: Transduction efficiency in the presence of SCF + FL + IL-3 was higher than that in other combinations of cytokines (SCF + IL-6 + IL-3, SCF + IL-6 + IL-3 + Tpo, SCF + IL-3). Transduction efficiency (20.5%) in the presence of bone marrow stromal cells plus cytokines (SCF + FL + IL-3) was higher than that (15.2%) without stromal cells, and the number of drug-resistant colony-forming cells was more in the former than in the latter. The percentage of CD(34)(+) cell with the gene transduction at 10 ng/ml Taxol reached 38.5%. CONCLUSION: Human bone marrow stromal cells plus cytokines (SCF + FL + IL-3) is more effective in enhancing mdr1 gene transduction. Taxol at a certain concentration can enrich mdr1 gene transferred cells.

Antigens, CD34↗

PubMed2000

[Autologous bone marrow transplantation for patients with chronic myelogenous leukemia after in vitro purging of the graft with bcr/abl antisense oligodeoxynucleotides].

OBJECTIVE: To investigate the efficacy of autologous bone marrow transplantation (ABMT) for patients with chronic myelogenous leukemia (CML) after in vitro purging of the graft with bcr/abl antisense oligodeoxynucleotides (AS-ODN). METHODS: Five CML patients, 2 in chronic phase (CP), 1 in accelerated phase (AP) and 2 in blast crisis (BC), all confirmed the presence of b3a2 bcr/abl mRNA by RT-PCR (reverse transcriptase-polymerase chain reaction). Patients had received 2 courses of intensive chemotherapy for "in vivo purging" before bone marrow harvesting. The autologous bone marrow cells were concentrated by CS3000plus and then incubated with 18-mer phosphorothioate bcr/abl AS-ODN (40 - 60 microg/ml, for 48 - 60 h). Conditioning regimens were TBI + Cy (total body irradiation + cyclophosphamide) or MAC + CCNU. RESULTS: After intensive chemotherapy, ph(+) cells in bone marrow reduced to 34% (24% - 46%) and the numbers of bcr/abl mRNA (+) CFU-GM to 45.6% (33% - 58%). After bcr/abl AS-ODN in vitro purging, two patients were bcr/abl mRNA negative and three positive with the number of bcr/abl mRNA (+) CFU-GM markedly reduced. Delayed hematopoietic reconstitutions were observed in all patients after ABMT. During a more than 2 years follow-up period, three patients obtained major cytogenetic remission (MCR) and lasted for 9 - 12 months and the durations of CP after ABMT were longer than that before ABMT. One of this three in BC before ABMT being survived disease-freely for 37 months with bcr/abl mRNA (-) after ABMT. Another patient in BC had a short duration of MCR and relapsed at +7 months. One patient died from severe infection and bleeding at day +74 because of delayed reconstitution. CONCLUSION: ABMT with bcr/abl AS-ODN purged graft can result in quite long duration of MCR and prolonged CP in some patients with CML.

Adolescent↗

PubMed2000

[The electron microscopic study of AchR and ultrastructure of neuromuscular junction in recurrent laryngeal nerve reinnervation].

OBJECTIVE: The purpose of this study was to observe the distribution of Acetylcholine receptor (AchR) and ultrastructural changes of the neuromuscular junction after laryngeal reinnervation. METHODS: alpha-bungarotoxin-horseradish peroxidase (alpha-BT-HRP) conjugate electron microscopic immunocytochemical methods and computer analysis of intensity of immunocytochemical reaction were applied to observe the distribution and relative quantity of junctional N-AchR. RESULTS: The results showed that the synaptic nerve terminals and presynaptic membrane were segmentally disrupted and almost disappeared completely and were replaced by Schwann's cells at 3 weeks after neurorrhaphy. At 6 weeks, some of the regenerating axons grew to the neuromuscular junctions and all the muscle fibers were reinnervated at 12 weeks. But the original postsynaptic membranes were only partially in contact with the regenerated nerve terminals. These conditions persisted until 18 weeks after neurorrhaphy, when remyelination was found in the vicinity of the neuromuscular junctions. The N-AchR reaction product on the postsynaptic membrane were increased greatly about 1.28 times more than the normal at 3 weeks after neurorrhaphy. The reactive products decreased greatly which was only 0.47% of that in the normal at 6 weeks. It remained low until 12 weeks after neurorrhaphy, which was 0.72% of the normal side. It increased obviously to 0.83 times of normal sides at 18 weeks and didn't changed there after. CONCLUSION: The state of reinnervation determines the quantity of neuromuscular junctional N-AchR.

Animals↗

PubMed2000

[XPS and AES studies of the Ni-P-SiO2 composite coating].

The morphology and composition of the composite coating of the Ni-P-SiO2 were analyzed by using the methods of SEM, AES and XPS. The results show the composite deposit is very smooth, uniform and good appearance. The coating is approximately 6.40 microns thick and has stronger corrosion resistance. The relative atomic percent contents of the coating is Ni 74.56%, P 12.38%, Si 2.77%, O 6.65% and Fe 2.32%.

English Abstract↗

PubMed2000

[The noise-filtering of chemiluminescence spectra with wavelet multiresolution analysis].

In this paper, the wavelet multiresolution signal decomposition was successfully applied to the filtering of high-frequency noise in chemiluminescence spectra. The spectra signal-to-noise ratio was greatly improved while the noise was suppressed effectively. The effect of wavelet basis and time of decomposition are also discussed. It is shown that the wavelet analyses have many advantages in processing of discrete signals.

Algorithms↗

PubMed2000

[Interference and interference-restraining in flame-emitting method].

When the flame-emitting method is used to determine certain element of alkali metal and alkaline-earth metal, some other external substances will interfere in the sample-determing. This passage put forwards some efficient ways of restraining the interference. It suggests that appropriate kinds of releasing agent should be added, and the radiant energy of flame itself should be controlled so as to find out the best way to improve the accuracy of analysing.

English Abstract↗

PubMed1999

Determinaton of two major metabolites of the novel anti-tumour agent 5,6-dimethylxanthenone-4-acetic acid in hepatic microsomal incubations by high-performance liquid chromatography with fluorescence detection.

High-performance liquid chromatographic methods have been developed and validated for the glucuronidated and oxidative metabolites of the novel anti-tumour agent 5,6-dimethylxanthenone-4-acetic acid (DMXAA), produced in human liver microsomal incubations. Calibration curves for DMXAA acyl glucuronide (DMXAA-Glu) and 6-hydroxymethyl-5-methylxanthenone-4-acetic acid (6-OH-MXAA) were constructed over the concentration ranges of 0.25 to 20 and 0.5 to 40 microM, respectively. Assay performance was determined by intra- and inter-day accuracy and precision of quality control (QC) samples. The difference between the theoretical and measured concentration, and the coefficient of variation, were less than 15% at low QC concentrations, and less than 10% at medium and high QC concentrations for both analytes. The methods presented good accuracy, precision and sensitivity for use in kinetic studies of the glucuronidated and oxidative metabolites of DMXAA in human liver microsomes.

Antineoplastic Agents↗

PubMed1999

Negative feedback regulation of TGF-beta signaling by the SnoN oncoprotein.

Smad proteins mediate transforming growth factor-beta (TGF-beta) signaling to regulate cell growth and differentiation. The SnoN oncoprotein was found to interact with Smad2 and Smad4 and to repress their abilities to activate transcription through recruitment of the transcriptional corepressor N-CoR. Immediately after TGF-beta stimulation, SnoN is rapidly degraded by the nuclear accumulation of Smad3, allowing the activation of TGF-beta target genes. By 2 hours, TGF-beta induces a marked increase in SnoN expression, resulting in termination of Smad-mediated transactivation. Thus, SnoN maintains the repressed state of TGF-beta-responsive genes in the absence of ligand and participates in negative feedback regulation of TGF-beta signaling.

Cell Division↗