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Biomedical subjects

Z Yu

Publications and source records attributed to Z Yu.

At least 217 records · Page 12Linked to original sources
PubMed1998

Long-term Effects of Various Iodine and Fluorine Doses on the Thyroid and Fluorosis in Mice.

OBJECTIVE: To elucidate the participation of the independent and combined long term effect of various concentrations of iodine and fluorine on the pathogenesis of goiter and fluorosis in mice. METHODS: Nine drinking water supplies with different iodine and fluorine content were prepared by combination of potassium iodate and sodium fluoride solutions in bidistilled water. The concentrations of iodide were: 1. iodine deficiency (ID): 0.0; 2. iodine normal (IN): 20.0; 3. iodine excess (IE) 2500.0 ug/l; and these of fluoride were: 1. fluoride deficiency (FD) 0.0; 2. fluoride normal 0.6; 3. fluoride excess (FE), 30.0 mg/l. A total of 288 Kunmim mice was divided into 9 groups consisting of 32 animals each and each group, in addition to basal diet, received one of following iodide/fluoride mixtures: ID+FD, ID+FN, ID+FE, IN+FD, IN+FN, IN+FE, IE+FD, IE+FN, IE+FE. By such manner, one half of the animals of each group was treated for 100 days and the other half for 150 days. RESULTS: It was found that ID only and IE only could both induce the goiter. FE induced dental fluorosis and increased fluorine content in the bone. In addition, fluorine also affected the thyroid changes induced by ID or IE. After 100 days of treatment, fluorine showed some stimulatory effect on the thyroid in ID conditions and inhibitory effect in IE conditions. After 150 days, however, the effects of fluorine on the thyroid reversed as compared with that of 100 days. On the other hand, difference of iodide intake could also increase the toxic effects of FE on the incisors and bones. The rate and degree of the incisor fluorosis, the fluorine contents in the bone were significantly higher in the ID+FE group than those in the IN+FE and IE+FE groups. CONCLUSIONS: Both iodine deficiency and excess induced goiter as well as other functional and histopathological changes in the mouse thyroid. Excessive fluorine caused fluorosis of incisors and limb bones. In addition, iodine and fluorine do have mutually interacting effects on both goiter and fluorosis in the experimental mice.

Journal Article↗
PubMed1998

Detection of p53 gene mutations in human leukemia by PCR-SSCP analysis and direct nucleotide sequencing.

OBJECTIVE: To look for mutations of the p53 gene in leukemic patients and study the relationship between abnormalities in p53 gene and leukemogenesis. METHODS: The peripheral blood and Bone Marrow Samples were collected from 36 patients with various leukemia types including 14 cases of lymphocytic leukemia [8 cases of acute lymphocytic leukemia (ALL), 4 cases of chronic lymphocytic leukemia (CLL), 2 cases of hairy cell leukemia (HCL)] and 22 cases of myelocytic leukemia [11 cases of acute nonlymphocytic leukemia (ANLL), 11 cases of chronic myelocytic leukemia (CML)]. DNA structures of exon 5-8 of the p53 gene were scanned by PCR-SSCP (single strand conformation polymorphism analysis of polymerase chain reaction products). The appropriate DNA fragments were amplified, Purified and sequenced directly. RESULTS: By PCR-SSCP analysis, shifts in electrophoretic mobility of the p53 gene were detected in 3 of 14 patients with lymphocytic leukemia (2 ALL and 1 CLL), but none in 22 patients with myelocytic leukemia including one in blastic crisis. Direct nucleotide sequencing in one patient with ALL showed transition of CTG to CAG at codon 257 of exon 7, resulting in a change of its encoded amino acids from aspartic acid to valine. To our knowledge, the mutation at this codon has not been previously reported hitherto. CONCLUSIONS: The p53 gene mutations are specifically associated with lymphocytic leukemia. Alternations of the p53 gene may play a certain role in leukemogenesis in some cases of lymphocytic leukemia.

Exons↗
PubMed1998

[Role of programmed cell death in mediating arsenic-induced rat embryo anomalies].

With a view to further investigating teratogenicity, embryotoxicity and teratogenic mechanism of arsenic on developing embryos, the relationship between apoptosis (programmed cell death, PCD) and arsenic-induced teratogenesis was studied during head-fold stage by using in situ 3'end-labeling of DNA and Nile blue sulfate (NBS) vital staining. Sprague-Dawley rats were intraperitoneally injected on gestation day 9.5 with doses of 0, 1, 4 and 8 mg/kg arsenic respectively, and killed at day 12, the results show that teratogenic incidence and mortality increased to 35.7% and 23.8% respectively, in apparent dose-effect relationship. In NBS staining experience, it was found that arsenic induced PCD in many areas, which related with abnormal development of brain, optic system, somite segmentation, limb bud and so on. In situ 3' end-labeling of DNA further supported above-mentioned results. The positive rate of apoptotic cell death was up to 55.6% (P < 0.05). This research suggested a positive correlation between abnormal PCD and teratogenesis. It may be seen that over-apoptosis is one of teratogenic mechanisms of arsenic. Moreover, our results show that necrosis plays some role in teratogenesis as well.

Abnormalities, Drug-Induced↗
PubMed1998

[Comparison of prognosis between inguinal cryptorchic seminoma and scrotal seminoma].

OBJECTIVE: To analyse the prognosis of patients with inguinal cryptorchic seminoma. METHODS: From 1985 through 1991, 43 patients with inguinal seminoma of undescended testis were treated and the therapeutic effect retrospectively reviewed. There were 33 patients in stage I, 8 in stage II, 1 in stage III, and 1 in stage IV. All patients had inguinal orchiectomy. Patients in stage I and II were primarily treated with radiotherapy, whereas one patient in stage III and another in stage IV were treated with radiotherapy or chemotherapy. RESULTS: The 5- and 10-year overall survival was 93.0% and 90.3%, respectively. The corresponding disease-free survival was 88.1% and 85.3%, respectively. The overall 5- and 10-year survival by stage was 100% and 100% for stage I, 75.0% and 60.0% for stage II, respectively. Two patients relapsed and were successfully treated with radiotherapy. CONCLUSION: Prognosis for inguinal cryptorchic seminoma is as good as that of scrotal testicular seminoma. Postorchiectomy radiotherapy encompassing para-aortic and ipsilateral iliac nodes is effective for stage I and early stage II inguinal crytorchic seminoma. The inguinal nodes should be included in the treatment ports only when they are involved or if there is obvious involvement of surrounding tissues by the primary tumor.

Adolescent↗
PubMed1998

[Ultrastructure of the tectorial membrane in chick inner ear].

In order to understand the ultrastructure of the tectorial membrane(TM) in avian inner ear and the relations between TM and hair cells and supporting cells, scanning electron microscope(SEM) and transmission electron microscope (TEM) were used to observe the ultrastructure of TM in chick inner ear. The results were that: when viewed under SEM, TM, which possessed a lot of holes inside, was triangular in shape in cross-section and the surface of TM presented fibrous net; when viewed under TEM, TM consisted of fine fibrils and gelatinous substance, only the tallest row of stereocilia and the kinocilium in each hair cell were inserted to TM. The microvilli of supporting cells were anchored to TM by cotton-like fibrous webs. This junction had both elastic and firm, to a certain extent, this kind of junction restricted the movement of TM. According to these structures, there should be different patterns of response to sound stimuli between avian cochlea and mammalian cochlea.

Animals↗
PubMed1998

[Construction of the internal standard RNA and DNA templates for MRP gene quantitative RT-PCR analysis].

OBJECTIVE: To construct the internal standard RNA and DNA templates for quantitative reverse transcription-polymerase chain reaction (RT-PCR) and quantitatively measure the mRNA expression of MRP gene. METHODS AND RESULTS: A 292 bp fragment was amplified by PCR from plasmid pRC/RSV-MRP containing full-length MRP cDNA and inserted into the Sma I site of PUC19 vector, constructing a recombinant plasmid-pUMRP292. A 238 bp HGV fragment was amplified by PCR from plasmid pUHGV and inserted into the Cla I site of pUMRP292, constructing a new recombinant plasmid-pUMRP 292/HGV as the internal DNA competitive template for quantitative PCR of MRP. A 530 fragment containing the 292 bp of MRP and the 238 bp of HGV was cut down by EcoR I and Xba I pUMRP292/HGV and cloned into the transcriptional vector pSP72 by the same enzyme sites, constructing a recombinant plasmid-pSMRP292/HGV, and then pSMRP292/HGV was cleaved with EcoR V and transcripted in vitro by SP6 RNA polymerase, obtaining a 530 bp mutant MRP-RNA positive strand as the internal RNA competitive template for quantitative RT-PCR. CONCLUSION: The established quantitative RT-PCR assay is simple, rapid and sensitive, and the DNA competitive template is more simple, economic and reliable than the RNA one.

ATP-Binding Cassette Transporters↗
PubMed1998

[The relationship between cytosolic Ca2+ and two kinds of granule number in activated platelets].

The numerical density (Nv) of the alpha-granule (alpha G) and dense granule (dG) measured by using electron microscopic morphometry and the cytosolic free calcium concentration ([Ca2+]i) by using Ca-fluorescent indicator were observed for studying the relationship of [Ca2+]i and Nv of alpha G and dG in platelets activated by A23187, thrombin or ADP. The results showed that the [Ca2+]i rose markedly by A23187. Thrombin or ADP could also induce an increase of [Ca2+]i concentration-dependently. Under 3 different degrees of activation induced by different agonists, the close relationship between Nv of both granules, alpha G and dG, and [Ca2+]i in platelets was found (Pr(alpha G) < 0.05, Pr(dG) < 0.01). These findings indicate that the increase in [Ca2+]i may enhance the secretion of alpha G and dG.

Animals↗
PubMed1998

[Clinical study of tubal pregnancy treated with integrated traditional Chinese and Western medicine].

OBJECTIVE: To explore the therapeutic effect and the mechanism of tubal pregnancy (TP) treated with integrated traditional Chinese and Western medicine (TCM-WM). METHODS: Seventy-eight patients suffering from TP were divided into two groups at random, 50 cases of treated group treated with the method of integrated Methotrexate (MTX) and Ectopic Pregnancy 2 (EP2) decoction, and the other 28 cases treated with MTX alone for control. RESULTS: The nonsurgical method cure rate of the treated group (98.0%) was higher than that of the control group (75.0%, P < 0.01). The intrauterine pregnancy rate of the treated group was 80.0%, that of the control group was 42.9% (P < 0.01). The recurrent TP rate of the treated group (4.0%) was lower than that of the control group (14.2%, P < 0.01). The serum beta-HCG normalizing time of the treated group (25.0 +/- 7.8 days) was shorter than that of the control group (31.9 +/- 6.7 days, P < 0.05). The total disappearance time of TP mass was 1.2 +/- 0.7 months in the treated group, and in the control group was 5.6 +/- 3.7 months (P < 0.01). After treated by EP2 decoction for 4-8 weeks, the deformability of erythrocyte was increased, the aggregation of erythrocyte, the whole blood viscosity and the blood plasma viscosity were reduced. CONCLUSIONS: The integrated method can effectively increase nonsurgical cure rate, tubal patency rate and intrauterine pregnancy rate, decrease recurrent TP rate in treating TP.

Adult↗
PubMed1998

[Tail-suspended rats with inguinal canal ligation and their myocardial function].

To examine the effect of testosterone level on myocardial contractility and to prevent the testis from sliding into abdominal cavity when subjected to tail-suspension, a new tail-suspended model of rat with its inguinal canal ligated was made. Rats suspended for 4 w without inguinal canal ligation (SUS) exhibited significant reduction in weight of testis (CON 1.70 +/- 0.19 g; SUS 0.60 +/- 0.16 g) and in serum testosterone level (CON 99.5 +/- 32.7 ng/dl; SUS 23.0 +/- 13.2 ng/dl) (P<0.01). Unexpectedly, 4 w tail-suspension of rats with inguinal canal ligation (ST) also showed significant changes in testis weight (1.21 +/-0.30 g) and serum testosterone level (40.7 +/- 32.6 ng/dl). A significant decrease of the developed tension of the papillary muscle of the left cardiac ventricle was observed in SUS and ST group as compared with controls (CON: 3.93 +/- 0.42 g/mm2, SUS: 2.54 +/- 0.85 g/mm2, ST: 2.60 +/- 0.73 g/mm2). There was no relationship between the developed tension and serum testosterone level. It suggests that the decrease of blood supply of the testis may result in an atrophy of the testis in ST group.

Animals↗
PubMed1998

[Study on the anti-herpes simplex virus activity of a suppository or ointment form of Astragalus membranaceus combined with interferon alpha 2b in human diploid cell culture].

A study on the anti-herpes simplex virus activity of the suppository or ointment form of Astragalus membranaceus(AM) combined with recombinant human interferon alpha 2b(IFN) was carried out in human diploid cell culture. AM is a Chinese herb medicine and have been used in China as a tonic for thousands of years and the IFN was produced from E. coli with 95% purity. Obtained results indicated that the placebo suppository and ointment(without AM and IFN) seemed not to decrease markedly the anti-viral activity of IFN in WISH/VSV assay system. The anti-herpes simplex virus activities of suppository and ointment forms of AM and IFN were shown to be significantly higher than that of IFN alone. It is well known that chronic cervicitis is closely related to papillomavirus, cytomegalovirus as well as herpes virus infections. The AM-IFN suppository is suggested to be used in the treatment of cervicitis and the ointment in the treatment of skin herpes.

Antiviral Agents↗
PubMed1998

[Expression characteristic of Bacillus thuringiensis cry1 gene in Pseudomonas fluorescens Pfx-18].

The plasmids of lepidopteran-specific Bacillus thuringiensis strain from our laboratory were hybridized with RNA probe of cry 1Aa EcoR I-F fragment labelled using DIG. Cry1 gene was located in 39.3 MD plasmid. The plasmid was digested with Hind III and analysed by southern blot. It appeared both 7.1 kb and of 6.5 kb positive bands. The 7.1 kb fragment was ligated to broad-host-range vector pSUP106 and transformed into Pseudomonas fluorescens Pfx-18. The cloned strain, LZP-1 was obtained. The plasmids of LZP-1 were analysed by PCR. The results showed that gene-type is cry1Ab. SDS-PAGE analysis demonstrated that LZP-1 could express 66 kD insecticidal crystal protein and some small molecular weight peptides. Bioassay showed that motality of 1000-fold diluted fermentation broth was 33% to 3rd instar plulella xyloslelly larvae.

Animals↗
PubMed1998

Combinatorial search for diagnostic agents: Lyme antibody H9724 as an example.

Two peptide libraries, Ac-MXXXXXBBRM and Ac-VXXXXXBBRM, were constructed on TentaGel solid support to search for ligands that bind tightly with the H9724 Lyme antibody. By using an on-bead ELISA, approximately 120 ligands were selected as candidates for further study. Matrix-assisted laser desorption ionization mass spectrometry analysis of the candidate ligands indicated a high rate of occurrence of certain amino acids at the randomized positions. On the basis of the initial screening results, a small library was designed and iteratively synthesized. Subsequent library screenings led to the identification of four peptides, Ac-PQEEGX-NH2 (X = R, K, A, D), that showed specific affinity to the antibody. This combination of solid-phase screening and iterative synthesis is an effective strategy for rapid identification of ligands that bind tightly with disease-specific antibodies and should be applicable, at least in principle, to other ligand-receptor systems. This combinatorial library approach can also be a useful tool for the discovery of novel diagnostic agents.

Antibodies↗
PubMed1997

Evaluation of liquid chromatographic behavior of restricted-access media precolumns in the course of direct injection of large volumes of plasma samples in column-switching systems.

The chromatographic behavior of an alkyl-diol silica (ADS, 25 x 4 mm I.D.) and a semipermeable surface (SPS, 10 x 10 mm I.D.) supports two types of restricted-access media (RAM), which served as precolumns in column-switching systems for direct injection of large volumes of plasma samples (500 microl), was studied with regard to peak performance, retention and column back pressure. The adsorption of matrix proteins both on sealings (porous frits and sieves) and packings was also examined. Columns of ADS and SPS were unchanged after the injection of 10-20 ml human plasma under normal working conditions. Even when changes occurred on the precolumns (>50 ml of plasma in total), it was still possible to regenerate the column performance by replacing the column sieves, or by washing and removing columns from the system for a period, since the changes were more related to the blockage of sealings and/or the adsorption of proteins on the hydrophilic surfaces. Proteins could eventually be unspecifically adsorbed on the hydrophobic ligand of the support. It was found on one ADS column that the retention decreased by 20% and the pressure increased 30 bar after an intensive loading of 75 ml plasma (injection volume, 500 microl) without reconditioning procedure. Studies showed that the column sealings played the most important role for the lifetime of RAM columns. For ADS columns, using sieves without polytetrafluoroethylene (PTFE) nets were the best. No significant difference in column life span between SPS and ADS was found.

Adsorption↗
PubMed1997

Confirmation of cross-reactivity between Lyme antibody H9724 and human heat shock protein 60 by a combinatorial approach.

A library of Ac-XXXXXPAPRM decapeptides was prepared on a TentaGel solid support using the approach of split synthesis and the strategy of partial chain termination. Epitope screening of the library (17(5) approximately 1.4 x 10(6) decapeptides) with a Lyme monoclonal antibody (H9724) and subsequent MALDI-MS analysis of candidate peptides from colored beads revealed a consensus structure of Xi-DLSXj (Xi = V, L, Y; Xj = G, R). These identified sequences presented no homology to the natural epitope from Borrelia burgdorferi flagellin. However, they were found to resemble a fragment at the N-terminus of human heat shock protein (Hsp60). Our results confirmed that H9724 cross-reacts between bacterial and human proteins and provided support for an autoimmunity mechanism of Lyme disease.

Antibodies, Bacterial↗
PubMed1997

DNA immunization of neonates induces immunity despite the presence of maternal antibody.

Neonatal animals were not considered as suitable vaccine recipients either because of immune immaturity or because passively delivered antibody interferes with immune induction. In this report, we evaluated the response of neonatal mice to immunization with naked DNA encoding a herpes simplex virus (HSV) protein, and determined if maternally derived HSV antibody interfered with immunogenicity. Our results show that neonatal mice develop effective humoral and T cell responses after immunization with either DNA or inactivated vaccines. The nature of the responses to HSV immunization, however, was more Th2-like in neonates than in adults. Whereas neonatal mice from HSV-naive mothers responded well to both DNA and inactivated vaccines, only DNA immunization induced effective immunity in neonates born to immune mothers. Our results indicate that DNA vaccines might provide a useful means of immunizing young animals that still possess high levels of potentially interfering maternal antibody.

Animals↗
PubMed1997

A minK-HERG complex regulates the cardiac potassium current I(Kr).

MinK is a widely expressed protein of relative molecular mass approximately 15K that forms potassium channels by aggregation with other membrane proteins. MinK governs ion channel activation, regulation by second messengers, and the function and structure of the ion conduction pathway. Association of minK with a channel protein known as KvLQT1 produces a voltage-gated outward K+ current (I[sK]) resembling the slow cardiac repolarization current (I[Ks]). HERG, a human homologue of the ether-a-go-go gene of the fruitfly Drosophila melanogaster, encodes a protein that produces the rapidly activating cardiac delayed rectifier (I[Kr]). These two potassium currents, I(Ks) and I(Kr), provide the principal repolarizing currents in cardiac myocytes for the termination of action potentials. Although heterologously expressed HERG channels are largely indistinguishable from native cardiac I(Kr), a role for minK in this current is suggested by the diminished I(Kr) in an atrial tumour line subjected to minK antisense suppression. Here we show that HERG and minK form a stable complex, and that this heteromultimerization regulates I(Kr) activity. MinK, through the formation of heteromeric channel complexes, is thus central to the control of the heart rate and rhythm.

Animals↗
PubMed1997

Neurokinin-1 receptor antagonist SR140333: a novel type of drug to treat cerebral ischemia.

Substance P (SP) has been implicated in immune responses and could increase glutamate release, and inflammatory reactions are known to be able to potentiate ischemic damage. We have previously found that SP was over-expressed in cerebral ischemia and speculated that SP may play a role in exacerbating ischemic damage. In this study, we examined whether a neurokinin-1 (NK-1) receptor antagonist, SR140333, would have an effect on brain ischemia. Intra-cerebroventricular (i.c.v.) administration of SR140333 (30 micrograms) markedly reduced (37.1 +/- 7.8%, p < 0.001) infarct volume measured 24 h after focal cerebral ischemia in the rat. The SR140333-treated group also exhibited a significantly improved neurological function reflected by the neurological deficit score. The results represented the first demonstration that a NK-1 receptor antagonist may be a novel type of drug for treatment of cerebral ischemia.

Animals↗