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Biomedical subjects

S Zhang

Publications and source records attributed to S Zhang.

At least 433 records · Page 24Linked to original sources
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

[Use of Hopkins rod-lens coupled with grasping forceps sheaths for extraction of tracheobronchial foreign bodies].

OBJECTIVE: To study the clinical application of Hopkins rod-lens coupled with gasping forceps sheaths in the extraction of tracheobronchial foreign bodies. METHODS: Sixty-two patients with tracheobronchial foreign bodies were operated on with Hopkins rod-lens coupled with grasping forceps sheaths under direct telescopic view or TV watching. High frequency jet ventilation was used and BPs ECGs SaO2 were monitored in all cases. RESULTS: Sixty-two patients were all successfully operated on. The extraction was primarily successful in 90% of the cases; and secondarily successful in 7% of the cases. No death and serious complication occurred. CONCLUSION: Compared with conventional bronchoscopic foreign body extraction, this new instrument and technique make it possible for the operator to clamp and extract foreign body under direct telescopic view or TV watching. It has increased the accuracy and safety of bronchoscopic extraction of tracheobronchial foreign bodies.

Adolescent↗
PubMed2000

[Surgery for tumors of the root of neck].

OBJECTIVE: To investigate the clinical value of the surgery for tumors located in the root of the neck. METHODS: A retrospective study was made on 15 cases with tumors in the root of the neck. Seven patients had benign and 8 had malignant tumors. In the malignant group, 4 staged III and 4 staged IV. Patients with benign disease were followed up for more than 3 years, and patients with malignant tumors were followed up from 1 to 5 years (median 2 years). RESULTS: Resection via "L" incision in the root of the neck was employed in 13 cases (7 benign and 6 malignant, clavicle splitting in 1 case) and sternotomy in 2 cases. Only one case in the benign group had complication (chylous leakage). In contrast, 7 complications (2 subclavian vein tearing, 2 brachial plexus injury, 2 chylous leakage and 1 pneumothorax) occurred in 6 patients in the malignant group. The incidence of complication was significantly different between the two groups (P < 0.05). We observed no recurrence in both groups during the period of follow-up. CONCLUSIONS: This study showed that surgery of tumors located in the root of the neck is effective, although the incidence of surgical complication is high for the malignant ones.

Adolescent↗
PubMed2000

[Complications and its prevention in 227 cases of childhood tracheotomy].

OBJECTIVE: To explore the correlation between the occurrence and the prevention of complications in childhood tracheotomy. METHODS: A total of 227 cases of childhood tracheotomy were analyzed based on clinical data from March 1974 to July 1999. RESULTS: Of 227 cases, 189 were decannulated successfully. Twenty-three cases discharged with tracheotomy tube. Fifteen cases died of primary disease. Fourteen of 227 cases had complications. Among them, 2 had intraoperative suffocation, 1 had trauma of esophagus, 5 complicated subcutaneous emphysema in cervical region and 1 had mediastinal emphysema. Five of 14 cases had postoperative drop out of the tube, 2 of them died of suffocation. CONCLUSION: The occurrence of complications is related to age, original disease, operative method and nursing.

Adolescent↗
PubMed2000

[Gastric solid emptying in diabetic rats and its respond to Chinese traditional medicine].

OBJECTIVE: To investigate the change of gastric solid emptying at different stages in diabetic rats, and the effect of Chinese traditional medicine(CTM) on gastric emptying. METHODS: 40 Wistar rats were randomly divided into three groups: CTM treated diabetic(15 rats), untreated diabetic(15 rats) and control(10 rats). Diabetes was induced by i.p. of streptozotocin(STZ), 65 mg/kg. CTM, 3.75 g/kg daily (consisting of Dan shen, Fu Ling mainly which functioned as Huo xue hua yu and Bu shen) was administrated in treated diabetic rats. Blood glucose and body weights were measured weekly. 12 and 24 weeks after induction of diabetes, gastric emptying was examined with scintigraphy for 240 min (30 min interval). A test meal (42 kJ) labeled with 99mTc-SC(2.96 x 10(5) Bq) was provided. RESULTS: (1) There were no significant differences in total gastric retention rate and T 1/2 among three groups at 12 weeks. (2) The lag phase of total stomach in DM-B was (41.56 +/- 8.39) min, shorter than in control's (67.50 +/- 9.09) min, (P < 0.05). (3) The proximal gastric retention rate of 12-week diabetes at 90 min were (38.2 +/- 6.2)% (vs control, P < 0.01), (16.0 +/- 7.9)% (vs control, P < 0.01), and (61.9 +/- 3.5)%; and of 24-week at 120 min were (21.3 +/- 6.8)% (vs control, NS), (48.5 +/- 8.2)% (vs control, P < 0.05, vs treated diabetes, P < 0.01), (28.3 +/- 6.4)% in treated, untreated and control group respectively. (4) There was negative correlation between blood glucose and gastric retention rate (r = -0.62, P < 0.05). CONCLUSION: (1) The proximal gastric solid emptying was impaired in diabetic rats, there was significantly accelerated in 12-week and slowed down in 24-week compared with control. (2) CTM could modify these impairment. (3) Hyperglycemia had positive correlation to gastric emptying in animal model, which might explain the clinic presentations of patients with diabetes in early stage.

Animals↗
PubMed2000

[Erythroid differentiation denucleation factor: a family of erythroid regulators for mammalian erythroid terminal differentiation/tumor suppression and the cloning of their related genes].

The role of regulation of erythroid differentiation denucleation factor(EDDF) on mammalian erythroid differentiation and myeloma cell malignancy as well as cloning of their stage related genes were serially studied. Through a series of cybrid and hybridization experiments between mammalian erythroid cells and erythroleukemia or non-erythroid myeloma cells, we have demonstrated a novel family of erythroid regulators(EDDFs) in the mammalian differentiating erythroblasts which with an active peak occurred concomitantly with marked decreases in DNA, RNA and the nuclear anchoring vimentin-IF, but increased in hemoglobin synthesis in cytoplasm prior to the denucleation process during terminal differentiation. The results of cell fusion experiments verified that the supplement of regulators(EDDFs) was critical to the recovery of the originally lost features of terminal differentiation and the reversion of malignant phenotype of tumor cells. Here we showed that the erythroid regulator family EDDFs were essential regulators for the sequential expression of stage related genes of erythroid terminal differentiation, and for the redifferentiation of tumor cells to express the originally inactive globe genes, repressed the oncogenes, and vimentin-IF system, thus initiated nuclear condensation and denucleation. The EDDF gene family consisted of MEDDF, HEDDF-1, HEDRF-1, HEDRF-2 and HCNBP-1 were cloned. All were novel cDNA sequences that have been searched and registered in GenBank. They expressed varying in a stage specific manner, and acted on corresponding genes of terminal differentiation.

Activins↗
PubMed2000

[Role of nitric oxide in excitotoxicity and memory impairment induced by kainic acid].

OBJECTIVE: The role of nitric oxide (NO) in excitotoxicity of kainic acid (KA) in the brain was investigated. METHODS: Adult female rats were bilaterally intra-caudate nucleus injected with KA. The nitric oxide synthase (NOS) was determined by measuring NO2- concentration produced from homogenized brain tissue in the enzyme response system at three time point after surgery. Another groups of rats were daily administrated (i.p.) L-NAME(10 mg/kg) or 7-NI(25 mg/kg) at 2nd to 6th day after intra-caudate KA injection. Behavioral tests for learning and memory were started at 10th day after surgery. RESULTS: NOS activity in caudate nucleus remained unchanged in 6-8 hours after surgery. It increased significantly in 3 days and slightly increased in 5 days after surgery. Both L-NAME and 7-NI ameliorated memory impairment induced by KA injection in passive avoidance response task. Only L-NAME improved KA-induced deficit in active avoidance response behavior. CONCLUSIONS: This study gives further evidence that NOS activation and excessive NO may mediate KA-induced excitotoxicity. Early and repetitive use of NOS inhibitors shows some protective effect on memory deficit induced by KA excitotoxicity.

Animals↗
PubMed2000

[Gastro-pyloro-duodenal motor cooperation in patients with dyspepsia].

OBJECTIVE: To investigate the role of the midgastric transverse band(MTB) and gastro-pyloro-duodenal motility in functional dyspepsia (FD) and diabetic dyspepsia (DD). METHODS: Healthy subjects, patients with FD and DD participated in the study. Of them, 65 subjects received radionuclide gastric emptying, 48 complex ultrasonograph, and 35 gastro-pyloro-duodenal manometry. RESULTS: (1) MTB was (7.01 +/- 1.31), (3.39 +/- 0.21) cm in FD and DD, which was significantly wider than that in HS group [(2.42 +/- 0.16) cm, P < 0.01, P < 0.001]. (2) The half gastric emptying time (t 1/2) in FD and DD were prolonged, gastric remained rate at 120 min increased, the gastric emptying velocity reduced when compared with HS. (3) The gastric occlusive and non-occlusive peristaltic contractions could be clearly shown under ultrasonograph. The percentage of emptying circle > 10 seconds was reduced in FD and DD. (4) There was decreased number of migrating motor complex phase III in FD and DD, when compared with HS. CONCLUSIONS: MTB is an area with physiological function, which affects intra-gastric food distribution. Patients with FD and DD showed delayed gastric emptying associated with decreased gastric motor activity and antro-pyloro-duodenal in-cooperative function. There may be different pathogenesis in FD and DD. Further study needs to be performed.

Adult↗
PubMed2000

[A simplified six-item checklist for screening of fragile X syndrome].

OBJECTIVE: To investigate whether a simplified six-item checklist could be developed to improve the screening fragile X syndrome test result. METHODS: Nine clinical characteristics were selected from patient records of 190 male and 18 female pediatrics for fragile X screening test were analyzed. The characteristics included mental retardation, family history of mental retardation, elongated face, large or prominent ears, attention deficit hyperactivity disorder, Autistic-like behavior, simian crease, macroorchidism, and hyperextensible joints. RESULTS: Seven cases were diagnosed with fragile X syndrome by Southern analysis on PCR product. Among the nine characteristics, simian crease, macroorchidism, and hyperextensible joints were eliminated, because of low frequency and statistical insignificance. Using remaining six-item clinical checklist, if a score of 6 or more was used as the criteria for screening fragile X test, about 60% of this test in our cases could have been eliminated clinically without missing any positive cases. Thereby the proportion of case with positive results improved 8.8%. CONCLUSIONS: With our simplified six-item clinical checklist, 60% of testing could have been eliminated clinically, thereby improving the effectiveness of fragile X screening test and promoting the proportion of cases with positive results in two groups.

Adolescent↗
PubMed2000

[Study on the determination of contents of Zn, Cu and Co by using artifical neural network and ultraviolet spectrum].

By means of artificial neural network and back-propagation train algorithm, the three-component metal coordinate compounds of PAR-Zn, Cu, Co were determined simultaneously, in which the spectra overlapped. In 580-440 nm, the absorbance(A) at 14 wavelength were taken as character parameter of artificial neural network, and samples were arranged by method of uniformity design. The mean recovery of Zn, Cu, Co were 95.22%, 95.98% and 100.5%. The experiment results show that the determination is accurate, and the method has good performance.

Cobalt↗
PubMed1999

Neurotransplantation of magnetically labeled oligodendrocyte progenitors: magnetic resonance tracking of cell migration and myelination.

Demyelination is a common pathological finding in human neurological diseases and frequently persists as a result of failure of endogenous repair. Transplanted oligodendrocytes and their precursor cells can (re)myelinate axons, raising the possibility of therapeutic intervention. The migratory capacity of transplanted cells is of key importance in determining the extent of (re)myelination and can, at present, be evaluated only by using invasive and irreversible procedures. We have exploited the transferrin receptor as an efficient intracellular delivery device for magnetic nanoparticles, and transplanted tagged oligodendrocyte progenitor cells into the spinal cord of myelin-deficient rats. Cell migration could be easily detected by using three-dimensional magnetic resonance microscopy, with a close correlation between the areas of contrast enhancement and the achieved extent of myelination. The present results demonstrate that magnetic resonance tracking of transplanted oligodendrocyte progenitors is feasible; this technique has the potential to be easily extended to other neurotransplantation studies involving different precursor cell types.

Animals↗
PubMed1999

Metal regulation of metallothionein participation in redox reactions.

Like glutathione or dithiothreitol, metallothionein effects the formation of pancreatic ribonuclease A from its S-sulfonated derivative catalyzed by protein disulfide isomerase. EDTA increases the yield of ribonuclease A activity recovery with metallothionein but does not affect the reaction with glutathione or dithiothreitol. EDTA also increases the reactivity of thiol groups in metallothionein with 5,5'-dithiobis-(2-nitrobenzoic acid) by chelation of zinc ions. It is suggested that the thiol groups in metallothionein form a part of the pool of cellular thiols in the regulation of cellular redox reactions and their availability is modulated by zinc chelation.

Animals↗
PubMed1999

Prospective study of body mass index, weight change, and risk of adult-onset asthma in women.

BACKGROUND: Obesity and asthma are common disorders, and their prevalence rates continue to rise. Although individuals with asthma may gain weight as a result of activity limitations, the relationship between body mass index (BMI), which is calculated as weight in kilograms divided by the square of height in meters, and risk of developing asthma is not known. METHODS: We performed a prospective cohort study of female US registered nurses in the Nurses' Health Study II. In 1991, after excluding women who died with probable asthma or with incomplete data, there were 85911 participants, aged 26 to 46 years. The main outcome measure was self-report of physician-diagnosed asthma with recent use of an asthma medication. RESULTS: From 1991 to 1995, we identified 1596 incident cases of asthma. In a multivariate model controlling for 9 potential confounding factors (including age, race, smoking, physical activity, and energy intake), the relative risks of asthma for 6 increasing categories of BMI in 1991 were 0.9, 1.0 (reference), 1.1, 1.6, 1.7, and 2.7 (P for trend <.001). Stronger associations were found using stricter definitions for asthma, and the finding was present in a variety of subgroups. In analyses controlling for the same variables, as well as BMI at age 18, women who gained weight after age 18 were at significantly increased risk of developing asthma during the 4-year follow-up period (P for trend <.001). CONCLUSIONS: The BMI has a strong, independent, and positive association with risk of adult-onset asthma. The increasing prevalence of obesity in developed nations may help explain concomitant increases in asthma prevalence.

Adult↗
PubMed1999

A Novel pH-Sensitive MRI Contrast Agent.

A tetrasubstituted derivative of 1,4,7,10-tetraazacyclododecane with amide coordinating groups and extended noncoordinating phosphonate groups forms a complex with gadolinium(III) (shown in the picture) which contains one slowly exchanging inner-sphere water molecule (tau(M)=21 µs). The 20-MHz water proton relaxivity of the complex was found to be highly pH dependent. Protonation of the noncoordinating phosphonate groups appears to catalyze prototropic exchange of the bound water protons, thereby providing a mechanism for enhanced water contrast below pH 7.

Journal Article↗
PubMed1999

Dietary fat and protein in relation to risk of non-Hodgkin's lymphoma among women.

BACKGROUND: Non-Hodgkin's lymphoma occurs more frequently in individuals with suppressed immune status, and some types of dietary fat and protein have been associated with decreased immune responses. In this study, we examined the intake of specific types of dietary fat and protein in relation to the risk of non-Hodgkin's lymphoma. METHODS: We documented 199 incident cases of non-Hodgkin's lymphoma in a cohort of 88 410 women, who were enrolled in the Nurses' Health Study and were aged 34-60 years in 1980, during 14 years of follow-up. Relative risks of the disease and 95% confidence intervals (95% CIs) were calculated. All P values are two-sided and were considered to be statistically significant for P<.05. RESULTS: Intake of saturated fat was associated with an increase in risk that was not statistically significant; the multivariate relative risk for the highest versus the lowest quintiles of intake was 1.4 (95% CI = 0.7-3.0; P for trend =.42). Intake of beef, pork, or lamb as a main dish was associated with a statistically significantly increased risk of non-Hodgkin's lymphoma; the multivariate relative risk for consumption of these meats at least once per day as compared with less than once per week was 2.2 (95% CI = 1.1-4.4; P for trend =.002). Higher intake of trans unsaturated fat was also statistically significantly associated with an increased risk of the disease; the multivariate relative risk for the highest versus the lowest quintiles was 2.4 (95% CI = 1.3-4.6; P for trend =.01). Higher intake of red meat cooked by broiling or barbecuing-but not by roasting, pan-frying, or boiling or stewing-was associated with an increase in risk that was not statistically significant. CONCLUSIONS: Greater dietary intake of certain meats and fats was associated with a higher risk of non-Hodgkin's lymphoma. These relationships and their potential mechanisms deserve further examination.

Adult↗
PubMed1999

Stage-specific expression of alpha1,2-fucosyltransferase and alpha1, 3-fucosyltransferase (FT) during mouse embryogenesis.

Lex [Galbeta1-4(Fucalpha1-3)GlcNAc] and Ley [Fucalpha1-2Galbeta1-4(Fucalpha1-3)GlcNAc] are both stage-specific embryonic antigens. Lex is first detected on the blastomeres of the 8-cell stage embryo, which correlates with the onset of blastomere compaction. Ley is highly expressed on the surface of the blastocyst, which has been shown to be involved in blastocyst attachment in the mouse. In the present study, mouse alpha1,2-FT (also known as FUT1) and alpha1,3-FT (also known as Fuc-TIV), which were responsible for Lex and Ley formation, were examined in preimplantation stage embryos by reverse transcription-PCR and in situ hybridization. alpha1,3-FT mRNA was detected in all embryos of preimplantation stage, while alpha1,2-FT mRNA emerged in the later stage embryos from 8-cell to 16-cell to the blastocyst. These results indicated the expression of Ley was regulated by alpha1,2-FT. In situ hybridization showed that these two enzyme mRNAs were detected only in morula and blastocyst stage embryos. The alpha1,2-FT and alpha1, 3-FT mRNAs were located in both the inner cell mass and the trophoblast cells. 2-Cell and 4-cell embryos were isolated from the oviduct and cultured in vitro to the 8-cell, morula and blastocyst stage. The expression of alpha1,2-FT and alpha1,3-FT were observed in these embryos developed in vitro; immunohistochemical analysis also showed that Ley expression was positive. These results suggested the stage-specific expression of Ley on the embryos was synthesized by endogenous alpha1,2-FT and alpha1,3-FT rather than transfer from other sources. In addition, the expression of alpha1, 2-FT was differentially regulated and the uterine factor was not prerequisite of the expression of Ley.

Animals↗
PubMed1999

Role of Ca2+ in apoptosis evoked by human amylin in pancreatic islet beta-cells.

The objective of these studies was to clarify the role of Ca(2+) in the mechanism of death evoked by human amylin (hA) in islet beta-cells. hA forms fibrils in vitro and islet amyloid in vivo. Here we show that pure synthetic hA aggregated in solution, formed fibrils and evoked death in cultured RINm5F islet beta-cells in a time-dependent (0-24 h) and concentration-dependent (0-20 microM) manner. Dying cells underwent shrinkage of the nucleus, with clumping and segregation of chromatin into masses that lay against the nuclear envelope, and internucleosomal DNA fragmentation. These cells therefore show many features of apoptosis, although aspects of the morphology might be characteristic of this particular cell type rather than of a general apoptotic nature. Aurintricarboxylic acid, an inhibitor of both Ca(2+)-dependent and Ca(2+)-independent nucleases, suppressed this DNA fragmentation and inhibited apoptosis at concentrations between 25 and 200 microM. Direct measurements of the cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)) in fura-2 acetoxymethyl ester (AM)-loaded beta-cells showed that neither hA nor its non-cytotoxic homologue, rat amylin were effective in raising [Ca(2+)](i). Modulators of Ca(2+) regulation were tested for their effects on hA-induced beta-cell apoptosis. Ca(2+) ionophore (A23187) and thapsigargin (an inhibitor of endoplasmic reticular Ca(2+)-ATPase activity) by themselves evoked apoptosis accompanied by increased [Ca(2+)](i). Neither the Ca(2+) channel blocker verapamil, the extracellular Ca(2+) chelator EGTA nor the cytosolic Ca(2+) buffer bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid ('BAPTA')/AM protected beta-cells from hA-evoked apoptosis. Prolonged incubation of beta-cells with a lethal dose of hA altered neither the basal [Ca(2+)](i) nor the thapsigargin-induced release of Ca(2+) from intracellular stores. Furthermore, (45)CaCl(2) uptake by RINm5F cells did not differ in the presence or absence of hA. These results suggest that, whereas alterations in cytosolic Ca(2+) homoeostasis do have a significant role in certain forms of beta-cell death, they do not contribute to the pathway of apoptosis evoked by hA in islet beta-cells.

Amyloid↗