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Biomedical subjects

N Wu

Publications and source records attributed to N Wu.

At least 55 records · Page 3Linked to original sources
PubMed1999

Uncv (uncovered): a new mutation causing hairloss on mouse chromosome 11.

A pair of mutant mice with a first sparse coat appeared spontaneously in the production stock of BALB/c mice with a normal coat. After being sib-mated, they produced three phenotypes in their progeny: mice with normal hair, mice with a first sparse coat and then a fuzzy coat, and uncovered mice. Genetic studies revealed the mutants had inherited an autosomal monogene that was semi-dominant. By using 11 biochemical loci--Idh, Car2, Mup1, Pgm1, Hbb, Es1, Es10, Gdc, Ce2, Mod1 and Es3--as genetic markers, two-point linkage tests were made. The results showed the gene was assigned to chromosome 11. The result of a three-point test with Es3 and D11Mit8 (microsatellite DNA) as markers showed that the mutation was linked to Es3 with the recombination fraction 7.89 +/- 2.19%, and linked to D11Mit8 with the recombination fraction 26.30 +/- 3.57%. The recombination fraction between Es3 and D11Mit8 was 32.90 +/- 3.81%. It is suggested that the mutation is a new genetic locus that affected the skin and hair structure of the mouse. The mutation was named uncovered, with the symbol Uncv. Further studies showed the mutation affected not only the histology of skin and hair but also the growth and reproductive performance of the mice. The molecular characterization of the Uncv locus needs to be further studied.

Alopecia↗
PubMed1999

Transgenic potato plants expressing osmotin gene inhibits fungal development in inoculated leaves.

Osmotin, a 24-KD protein isolated from Nicotiana tabacum 'Xanthi nc' was very toxic to Phytophthora infestans in vitro assay. Transgenic potato plants expressing wild osmotin protein delayed the emergence of symptoms of disease. Two osmotin mutants have been produced by PCR mutagenesis. One mutant, delta C18 osmotin, had a nonsense mutation near the C-terminus that deleted the carboxyl terminal prepropeptide (CTPP) of 18 amino acids. Another mutant, osmotin-P, had amber mutation at 96th amino acid. Both mutant genes driven by CaMV d35S promoter were introduced in potato by Agrobacterium mediated genetic transformation. The expression and osmotin protein accumulation in transgenic potato were detected by Southern, Northern, and Dot-blot ELISA assay. Disease resistance test using P.infestens complex race showed that expression of both osmotin mutants in transgenic potato reduced the lesion growth rate in inoculated leaves. The results showed that accumulation of osmotin protein in intercellular spaces (delta C18osmotin) inhibited the development of fungal disease in inoculated leaves. Based on the results we suggest that antifungal activity was possibly located at N end of osmotin protein (osmotin-P).

Blotting, Northern↗
PubMed1999

[The growth effect of granulocyte colony-stimulating factors on ovarian carcinoma cell lines].

OBJECTIVE: To evaluate the growth effects of granulocyte colony-stimulating factors (G-CSF) on ovarian carcinoma cell lines. METHODS: We investigated the possible growth effects of G-CSF on three ovarian carcinoma cell lines (SKOV3, 3AO, and CAOV3). Cell proliferation and viability was measured by XTT colorimetric assay. Flow cytometer (FCM) and G-CSF receptor mRNA were measured for response cell lines, the response cell lines were xenotransplanted into athymic mice, to investigated in vivo growth under systemic subcutaneous infusion of G-CSF. RESULTS: G-CSF showed no growth-stimulating effects in 3AO and CAOV3 cell lines. In SKOV3, an increase in growth (< 5%) was seen by XTT assay at 100 ng/ml and 1000 ng/ml after 24 hours treatment, but no significant proliferation was observed by FCM. No G-CSF receptor mRNA was detected by RT-polymerase chain reaction, and no significant alteration of the tumor growth was by G-CSF. CONCLUSION: Although, the above results suggest that G-CSF may act as growth factors in a few ovarian carcinoma cell lines, yet the worry about tumor growth stimulation by G-CSF as potential hazards for their clinical application in ovarian carcinoma patients as an adjuvant with cytotoxic chemotherapy is not necessary.

Animals↗
PubMed1999

[The supporting effects of the pedicle of the subdermal vascular network flap in the rat].

OBJECTIVE: To investigate the role of the pedicle in the survival of the subdermal vascular network skin flap. METHODS: The subdermal vascular network skin flap was created on the back of the rat in the experimental group. The subdermal vascular network skin graft was made at the same position of the rat in the control group. The ratio of length to width of the flap was 4:1. The observation was carried out with naked eyes and instrument. Hair growing on the flap was one of the most important indexes of the observation. RESULTS: It was observed in 116 animals that the proximal 25 percent of the flap possessed regular colour and well-growing hair. CONCLUSION: The pedicle of the subdermal vascular network skin flap in the rat can supply 25 percent of the whole flap.

Animals↗
PubMed1999

Treatment of early giant retinal tears with domestic perfluorodecalin and perfluoropropane.

OBJECTIVE: To explore the methods of lens-sparing (without lensectomy), non-silicone oil tamponade and no scleral buckling for treatment of early giant retinal tears. METHODS: Thirteen cases of early retinal detachment of proliferative vitreoretinopathy (PVR) grade C2-D1, with giant tear extending from 135 degrees to 270 degrees were chosen. Transscleral cryotherapy was first applied to treat each end of the giant tear up to the oral serrate. And then conventional three-port pars plana vitrectomy was performed. Perfluorodecalin liquid was injected to manipulate the flap of the retinal tear. The flap with no cryotherapy before was treated with endolaser or cryotherapy under optimal visual condition, then air-fluid was exchanged completely and C3F8 was injected properly. RESULTS: With a mean follow-up of 8.2 months, the retina was reattached completely in 12 eyes. Success rate was 92.3%, and visual acuity improved. Most postoperative complications were slight. The retina failed to reattach only in 1 case with severe vitreous blood. CONCLUSIONS: In treating early retinal giant tears without severe PVR, the lens-sparing, non-silicone oil tamponade and no scleral bucking are helpful to simplify operation and to improve the success rate of the retinal surgery and to yield satisfactory outcome of visual acuity. Besides, it can also avoid the initial side effects of silicone oil tamponade and diopter irregularity after lensectomy.

Adult↗
PubMed1999

[Expression of soluble 55 kD receptor for human tumor necrosis factor using baculovirus vector].

Total RNA was isolated from HeLa cells and about 530 bp cDNA encoding shTNFR55 was amplified with RT-PCR from the total RNA. The cDNA was cloned into the downstream of polyhedrin gene promoter in transfer vector pAcGP67B, and a recombinant transfer plasmid pAcTNFR was constructed. Insect cell sf9 was co-transferred with recombinant plasmid pAcTNFR and baculovirus AcNPV DNA. Recombinant virus AcNPV-TNFR containing shTNFR55 gene were formed by homologous recombination in insect cells. They were purified by plaque assay and were confirmed by DNA dot blot. The biological activity of expressed product was determined with culturing TNF-susceptible L929 cell line, and the result showed that the expressed product could neutralize the cytotoxicity of TNF on L929 cell line. Ligand blot analysis revealed the expressed protein three discrete bands between 20-25 kD.

Animals↗
PubMed1998

[Kinetic effect of testosterone or estradiol on iodine absorption in castrating rat intestine].

OBJECTIVE: To observe the effect of testosterone or estradiol on iodine absorption in rat intestine. METHOD: 50 male adult Wistar rats were divided into 5 groups randomly. 50 females were divided into another 5 groups. Among them, 4 groups were bilaterally testectomized or ovariectomized, 1 group was sham-operated. 7 days after operation, the castrated rats received testosterone (male rats) or estradiol (female rats) at different dosages by intramuscular injection for three days. Then the kinetics of iodine absorption in jejunum and ileum were observed by perfusion in situ. When finished, serum were obtained for detecting TSH, T4 and testosterone or estradiol. RESULTS: In castrated male rats, the value of K12 reduced, K21 increased, K02 reduced, and SP1/2 (the half time of the slow phase) prolonged, implying that the ability of iodine absorption reduced. It reflected that testosterone could promote iodine absorption in intestine in physiological condition. In castrated female rats, the situation was different from that in male rats, the value of K12 increased, K21 reduced, K02 increased, and SP1/2 shortened in jejunum, implying that the ability of iodine absorption increased. It reflected that estradiol could inhibit iodine absorption in intestine in physiological condition. The levels of serum TSH and T4 were not changed significantly in this experiment. CONCLUSION: In physiological condition, testosterone can promote iodine absorption, while estradiol has the inhibiting effect. The results indicate that gonadol hormone maybe one factor which can influence iodine absorption in intestine. It may explain the phenomenon that the incidence of goiter is different between males and females partly.

Animals↗
PubMed1998

Langmuir-Blodgett Film Formation of a Fullerene Dicarboxylic Acid Derivative C60(HOOCCHNHCHCOOH) and its Photocurrent Generation.

The Langmuir films of a fullerene dicarboxylic acid derivative I, C60(HOOCCHNH2CHCOOH)CF3SO3H (FDA), at the air/water interface have been investigated. FDA formed a stable monolayer on pure water when dilute solution (1.04 x 10(-5) mol/L) was used as the spreading solution. The monolayer formation on various subphases was investigated, including solutions containing different monovalent (Na+, Ag+) and divalent (Ca2+, Cd2+, Cu2+) cations. The introduction of these cations makes the monolayer more stable. The limiting molecular area is also dependent on the pH of the subphase. The surface pressure versus area isotherms at different temperature clearly indicate that FDA molecules easily aggregate at high temperature. The monolayer and multilayer LB films of FDA were deposited on quartz and glass substrates from Ca2+, Cd2+, Cu2+, or Cu2+/Phen solution subphase, and their UV-vis and XPS spectra were obtained. The data showed that for Cd2+ and Cu2+/Phen subphase the cation can be transferred onto the substrates together with FDA but not the other two. The photoelectrochemical behavior of FDA on an ITO electrode was investigated, which showed that the photocurrent is cathodic. Oxygen and negative bias are beneficial factors for the photocurrent generation. The external quantum yield is ca. 4%. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Comparison of the allosteric properties of the Co(II)- and Zn(II)-substituted insulin hexamers.

The positive and negative cooperativity and apparent half-site reactivity of the Co(II)-substituted insulin hexamer are well-described by a three-state allosteric model involving ligand-mediated interconversions between the three states: T3T3' right harpoon over left harpoon T3o R3o right harpoon over left harpoon R3R3' [Bloom, C. R., Heymann, R., Kaarsholm, N. C., and Dunn, M. F. (1997) Biochemistry 36, 12746-12758]. Because of the low affinity of the T state for ligands, this model is defined by four parameters: LoA and LoB, the allosteric constants for the T3T3' to T3o R3o and the T3o R3o to R3R3' transitions, respectively, and the two dissociation constants for ligand binding to T3o R3o and to R3R3'. The d-d electronic transitions of the Co(II)-substituted hexamer give optical signatures of the T to R transition which can be quantified, but the "spectroscopically silent" character of Zn(II) has made previous attempts to describe the Zn(II) species difficult. This work shows that the T to R state conformational transitions of the Zn(II) hexamer can be easily quantified using the chromophore 4-hydroxy-3-nitrobenzoate (4H3N). When the chromophore is bound to the HisB10 sites of the R state, the absorption spectrum of 4H3N is red-shifted, exhibiting strong absorbance and CD signals, whereas 4H3N does not bind to the T state. Hence, 4H3N can be employed as a sensitive indicator of conformation under conditions that do not significantly disturb the T to R state equilibrium. Using 4H3N as an indicator, these studies show that both LoA and LoB are made less favorable by the substitution of Co(II) for Zn(II); LoA is increased by 10-fold while LoB by 35-fold, whereas the ligand affinities of the phenolic pockets are unchanged.

Allosteric Site↗
PubMed1998

[Imaging manifestations of tumors metastasized in fatty liver].

OBJECTIVE: To evaluate the manifestations of tumors metastasized in fatty liver and the value of various imaging modalities, especially CT. METHODS: Nine cases of tumors metastasized in fatty liver were proved by clinical follow-up for 3-13 months. The primary neoplasms were breast carcinoma in 6 cases; ovarian carcinoma, malignant melanoma and colon carcinoma, one case for each. All had CT(19 episodes) and ultrasonography (US, 20 episodes). Four cases had MRI and 2 cases had DSA. RESULTS: Liver metastatic lesions were missed by US in 2 cases with moderate to marked fatty liver. On CT without contrast administrations, fatty liver was divided into marked, moderate and mild degree according to the density of hepatic parenchyma which was lower than that of the spleen; lower and higher than or equal to that of the intrahepatic blood vessels. Depending on the degree of fat infiltration(FI), the density of the metastatic lesions was high when FI was marked and low when FI was mild. However, when FI was moderate, the density of the metastatic lesions varied, being high, equal or low. On enhanced CT, all of the lesions were enhanced with moderate to marked fatty liver background. Lesions were heterogeneous in 4 cases. On plain CT, metastatic lesions had high-density rim, 2-6 mm in width in 4 cases. In SE sequence of MRI, metastatic lesions were hypointense on T1W and hyperintense on T2W, and moderately hyperintense on opposed-phase. CONCLUSION: Tumors metastasized in fatty liver show a broad spectrum of image manifestations. They are related to the degree of fat infiltration. On plain CT, isodense lesions are easily escaped detection when moderate degree of fatty liver is present. Contrast administrations is mandatory. Liver metastases is suggested if a lesion is found with hyperattenuating rim on plain CT, or appears heterogeneous after enhancement. MRI is of diagnostic help.

Adult↗
PubMed1998

[Two-phase dynamic CT and trans-abdominal ultrasonography for preoperative TNM staging of gastric carcinoma: a correlation study with surgery and pathology].

OBJECTIVE: To assess the value of two-phase dynamic CT and transabdominal ultrasonography in the preoperative staging of gastric carcinoma. METHODS: Two-phase dynamic CT was performed in 63 cases of gastric carcinoma confirmed histologically by fibro-gastroscopic biopsy. Of the 63 cases, 20 had trans-abdominal ultrasonography (US) immediately after CT examination. Imaging findings were correlated with surgical and pathologic findings. RESULTS: For evaluation of T and N staging, the accuracy of dynamic CT was 53.23% and 58%, respectively, that of CT in combination with US for T staging was 70%, which was statistically different from that of CT alone (P < 0.05). Accuracy of CT in combination with US for TNM staging was 90%, there was marked statistical difference (P < 0.05) compared with the accuracy of US. CONCLUSION: The major role of dynamic CT in combination with trans-abdominal ultrasonography for staging of gastric carcinoma is to ascertain whether the tumor has invaded adjacent structures-T staging, which is helpful in treatment planning.

Adolescent↗
PubMed1998

[Effects of IL-1 and TNF-alpha on the proliferation and cytosolic Ca2+ of lens epithelial cell in vitro].

OBJECTIVE: To study the effects of interleukin 1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) on the proliferation and cytosolic Ca(2+) of bovine lens epithelial cells (BLEC) in vitro. The effects of IL-1 and TNF-alpha on posterior capsular opacification (PCO) and the mechanism of effect on the proliferation were investigated. METHODS: The effects of IL-1 and TNF-alpha on the proliferation of BLEC were detected with MTT staining colorimetry, and cytosolic Ca(2+) was measured by fluorescence determination with Fura-2. RESULTS: IL-1 10(2) - 10(5) ng/ml, TNF-alpha 10(2) - 10(4) U/ml obviously could promote BLEC proliferation (P < 0.05 - 0.01), and increase cytosolic Ca(2+) (P < 0.05 - 0.01) at the same doses. CONCLUSIONS: IL-1, TNF-alpha contribute to the PCO. One of the mechanisms of IL-1 and TNF-alpha on proliferation is by cytosolic Ca(2+).

Animals↗
PubMed1998

[Treating early giant retinal tears altogether with perfluorodecalin and perfluoropropane].

OBJECTIVE: To study the method of lens-sparing (without lensectomy) and non-silicone oil tamponade for treating early giant retinal tears. METHOD: 13 early giant retinal tear cases were treated altogether with perfluoropropane and perfluorodecalin. RESULTS: The retinal reattachment rate was 92.3% and the visual acuity was obviously improved. CONCLUSION: The lens-sparing and non-silicone oil tamponade treatment of early retinal tears altogether with perfluorodecalin and perfluoropropane is helpful to improve the success rate of the retinal detachment surgery and the visual acuity outcomes.

Adult↗
PubMed1998

[Studies on the chemical constituents of chloroform extract of Dracaena cochinchinensis].

Six compounds were isolated from Dracaena cochinchinensis (Lour.) S.C. Chen. Their structures were identified as 2,3,5,6-tetracchloro-1,4-dimethoxybenzene (I), 7-hydroxy-4'-methoxyflavan (II), 4'-hydroxy-3,5-dimethoxystilbene (III), 4'-hydroxy-2,6-dimethoxydihydrochalcone (IV), 4'-hydroxy-2,4,6-trimethoxydihydrochalcone (V) and 6-hydroxy-7-methoxy-3-(4'-hydroxybenzyl) chromane (VI) by chemical method and spectral analysis. IV and VI are new compounds.

Chalcone↗
PubMed1998

[Studies on the fine stereostructure of taxoids].

The anticancer drug taxol is a new type antimicrotubular drug. The structure-activity relationship study on taxol and its analogs has indicated the importance of the C13 side chain and the C4-C5-C20 epoxypropane group. The crystal structures of 4 taxoids having the basic skeleton with 5/7/6 membered ring and three types of 10 taxoids having the basic skeleton with 6/8/6 membered ring have been analyzed. The effects of the induction by different substructures at C4 on the stereostructures of taxoids were studied, and the relationship between the 6/8/6/4 skeleton and the anticancer activity was discussed from the crystallographic point.

Antineoplastic Agents, Phytogenic↗
PubMed1997

Essential role of the first intron in the transcription of hsp90beta gene.

The human HSP90 gene family contains introns. There are two typical heat shock elements (HSE) in the first intron of human hsp90beta gene. As detected by chloramphenicol acetyl transferase (CAT) reporter activity assays, the HSE-containing intron is essential in maintaining high constitutive expression and is critical for heat shock inducibility of the human hsp90beta gene. Cellular heat shock factor 1 (HSF 1) shows much higher binding affinity toward the intronic HSEs in comparison to an atypical HSE in the 5' flanking sequence. Novel initiation sites found in the first intron probably also contribute to constitutive and heat-inducible expression of the hsp90beta gene in Jurkat cells.

Chloramphenicol O-Acetyltransferase↗
PubMed1997

Miz1, a novel zinc finger transcription factor that interacts with Msx2 and enhances its affinity for DNA.

Msx2 is a homeobox gene with a regulatory role in inductive tissue interactions, including those that pattern the skull. We demonstrated previously that individuals affected with an autosomal dominant disorder of skull morphogenesis (craniosynostosis, Boston type) bear a mutated form of Msx2 in which a histidine is substituted for a highly conserved proline in position 7 of the N-terminal arm of the homeodomain (p148h). The mutation behaves as a dominant positive in transgenic mice. The location of the mutation in the N-terminal arm of the homeodomain, a region which in other homeodomain proteins plays a key part in protein-protein interactions, prompted us to undertake a yeast two hybrid screen for Msx2-interacting proteins. Here we present a functional analysis of one such protein, designated Miz1 (Msx-interacting-zinc finger). Miz1 is a zinc finger-containing protein whose amino acid sequence closely resembles that of the yeast protein, Nfi-1. Together these proteins define a new, highly conserved protein family. Analysis of Miz1 expression by Northern blot and in situ hybridization revealed a spatiotemporal pattern that overlaps that of Msx2. Further, Miz1 is a sequence specific DNA binding protein, and it can function as a positive-acting transcription factor. Miz1 interacts directly with Msx2 in vitro and enhances the DNA binding affinity of Msx2 for a functionally important element in the rat osteocalcin promoter. The p148h mutation in Msx2 augments the Miz1 effect on Msx2 DNA binding, suggesting a reason why this mutation behaves in vivo as a dominant positive, and providing a potential explanation of the craniosynostosis phenotype.

Amino Acid Sequence↗