Biomedical subjects

S Wu

Publications and source records attributed to S Wu.

At least 109 records · Page 6Linked to original sources

PubMed2001

Identification of the human homologue of the early-growth response gene Snk, encoding a serum-inducible kinase.

Murine serum inducible kinase (mSnk) was recently cloned and characterized as an early-growth response gene involved in cell proliferation. Here we report the isolation and characterization of its human homologue, named hSnk. Sequence comparison shows that hSnk is highly conserved and its deduced protein sequence shares a significant amino acid identity with mSnk and rSnk proteins, as well as with other polo family kinase gene products. A survey of hSnk expression reveals that while a wide variety of human tissues express a low to moderate level of hSnk transcripts, fetal tissues, testis, and spleen express the most abundant hSnk transcripts. In addition, serum stimulation rapidly induces hSnk expression in fibroblast cells, reaching the peak level of induction within one hour post treatment. Considering that Plk and Prk, two other known human polo-family kinases, control cell cycle checkpoint and cell cycle progression, our current observations suggest that hSnk may also play an important role in cells undergoing rapid cell division or having a high mitotic index.

Adenosine Triphosphate↗

PubMed2001

Keratometric astigmatism after cataract surgery using small self-sealing scleral incision.

BACKGROUND: To evaluate the corneal refractive changes after a small self-sealing scleral wound. METHODS: A 4 mm self-sealing scleral tunnel incision and implantation of a foldable intraocular lens were adopted during phacoemulsification. A retrospective review of 48 consecutive isolated eyes in 48 patients was performed to assess the postoperative corneal refractive change. Keratometric readings were recorded for 3 months following surgery. RESULTS: At one week postoperatively there was a -0.29 +/- 1.02 (standard deviation) change of Naeser's polar value (against-the-rule shift) in the cylinder keratometry. The cylinder had with-the-rule shift and recovered to the preoperative state at one month postoperatively. The change of Naeser's polar value at the third postoperative month was 0.05 +/- 0.80 (with-the-rule shift) compared with the preoperative polar value. The change of astigmatism at the third postoperative month was -0.38 +/- 0.74 (Diopters) using simple subtraction and -1.01 +/- 0.58 (Diopters) using the Jaffe vector analysis. The axis of astigmatism exhibited a mild against-the-wound shift at 1 week and a gradual with-the-wound shift afterwards. CONCLUSION: The low induced astigmatism, early recovery of corneal curvature and no direct damage to the cornea support the concept and justify the use of a small self-sealing scleral tunnel incision during cataract surgery.

Adult↗

PubMed2001

Determination of nucleic acids with crystal violet by a resonance light-scattering technique.

For the first time, Crystal Violet (CV) was used to determine nucleic acid concentrations using the resonance light-scattering (RLS) technique. Based on the enhancement of the RLS of CV by nucleic acids, a new quantitative determination method for nucleic acids in aqueous solutions has been developed. At pH 5.03 and ionic strength 0.005 mol kg-1, the interaction of CV with nucleic acids results in three characteristic RLS peaks at 344.0, 483.0 and 666.0 nm. With 4.0 x 10(-5) mol l-1 of CV, linear relationships were found between the enhanced intensity of RLS at 666.0 nm and the concentration of nucleic acids in the range 0-2.5 micrograms ml-1 for herring sperm DNA, 0-4.0 micrograms ml-1 for calf thymus DNA and 0-4.5 micrograms ml-1 for yeast RNA. The limits of determination were 13.8 ng ml-1 for herring sperm DNA, 36.8 ng ml-1 for calf thymus DNA and 69.0 ng ml-1 for yeast RNA. The assay is convenient, rapid, inexpensive and simple.

Animals↗

PubMed2001

Contribution of endogenously expressed Trp1 to a Ca2+-selective, store-operated Ca2+ entry pathway.

Heterologous expression of the transient receptor potential-1 gene product (Trp1) encodes for a Ca2+ entry pathway, though it is unclear whether endogenous Trp1 contributes to a selective store-operated Ca2+ entry current. We examined the role of Trp1 in regulating both store-operated Ca2+ entry and a store-operated Ca2+ entry current, I(SOC), in A549 and endothelial cells. Twenty different 'chimeric' 2'-O-(2-methoxy)ethylphosphothioate antisense oligonucleotides were transfected separately using cationic lipids and screened for their ability to inhibit Trp1 mRNA. Two hypersensitive regions were identified, one at the 5' end of the coding region and the second in the 3' untranslated region beginning six nucleotides downstream of the stop codon. Antisense oligonucleotides stably decreased Trp1 at concentrations ranging from 10 to 300 nM, for up to 72 h. Thapsigargin increased global cytosolic Ca2+ and activated a I(SOC), which was small (-35 pA @ -80 mV), reversed near +40 mV, inhibited by 50 microM La3+, and exhibited anomalous mole fraction dependence. Inhibition of Trp1 reduced the global cytosolic Ca(2+) response to thapsigargin by 25% and similarly reduced I(SOC) by 50%. These data collectively support a role for endogenously expressed Trp1 in regulating a Ca2+-selective current activated upon Ca2+ store depletion.

Base Sequence↗

PubMed2001

[The effect of "qingxiangsan" on inhibiting oxidation and hepatic cells apoptosis in the wet-heat syndrome rat model].

OBJECTIVE: To observe the changes of oxidation and hepatic cells apoptosis in the wet-heat syndrome rat model, and the effect of "qingxiangsan" on inhibiting oxidation and hepatic cells apoptosis. METHODS: Wistar rats were divided into wet-heat syndrome group, qingxiangsan group and normal control group. Flow cytometry and electron microscopy were employed to detect hepatic cells apoptosis. SOD and MDA in the serum, LPO in the hepatic tissue were also estimated. RESULTS: Apoptotic morphogenetic changes, apoptotic rate increasing, activity of SOD decreasing, content of MDA and LPO increasing were obvious in the wet-heat syndrome group. In the "qingxiangsan" group, apoptotic rate decreasing, activity of SOD increasing, content of MDA and LPO decreasing were examined. CONCLUSION: "qingxiangsan" possesses the function of inhibiting oxidation and apoptosis in the wet-heat syndrome rat model.

Animals↗

PubMed2001

[Stress response of Nilaparvata lugens at high temperature and activities of its protective enzyme systems].

The nymphae and different wing-form adults of Brown Planthopper (BPH) were treated intermittently at 34 degrees C, 36 degrees C and 38 degrees C. During the process of heat shock treatment, the variation of the activities of the endogenous enzymes of protective system and the content of lipid peroxides (LPO) in BPH were researched. The results showed that the effect of heat shock treatments on CAT activity in 4th instar of nymphae was higher than that in 3rd and 5th instar. The CAT activity in BPH adults increased with the day-age, and 36 degrees C was the suitable temperature at which H2O2 was scavenged by CAT. The GSH-px activity was higher in old than that in young nymphae, and the ability of GSH-px to scavenge H2O2 was higher in old adults than in those adults emerged early. The activity of SOD had a positive correlation with the treated temperatures, and decreased with the increase of nymphae instar and the day-age of adults after emergence at the same temperature. The activities of CAT, GSH-px, and SOD in macropterous adults were higher than those in brachypterous adults. There were no significant difference for the activities of CAT, GSH-px and SOD between female and male adults (alpha > 0.05). The content of LPO in BPH increased with the rise of treated temperature, and also increased with the increase of instars in nymphae and day-age after emergence in adults at the same temperature. The LPO content was higher in brachypterous than in macropterous adults.

Animals↗

PubMed2001

Endothelial cell loss induced by phacoemulsification occurs through apoptosis.

BACKGROUND: Cornea endothelial cells are nondividing cells containing pumping function which is crucial for cornea clarity and integrity. Endothelial cell loss occurs after cataract surgical procedures such as phacoemulsification. The authors hypothesize that endothelium damage occurs through apoptosis. METHODS: Ultrasound was achieved by placing a phacoemulsification probe in the anterior chamber and delivering 0% or 50% of maximum power for 2.5 min. The corneal tissue was harvested immediately, and at 1 and 7 days after the operation. Corneal tissue was stained by hemotoxylin and eosin (H&E) and evaluated by light microscopy. Endothelium apoptosis was monitored using the terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling (TUNEL) assay to detect DNA fragmentation. RESULTS: In corneas which underwent phacoemulsification with 0% energy, no cell loss or apoptosis was identified immediately, 1 or 7 days after the operation. Likewise, in corneas exposed to 50% energy, no cell loss or apoptosis was detected immediately after phacoemulsification. However, minimal amount of cell loss but prominent apoptosis was detected with the TUNEL assay 1 day after the operation, whereas significant cell loss but no apoptosis was detected 7 days after the operation by H&E stain. CONCLUSIONS: These results demonstrate that corneal endothelial cell loss induced by ultrasound damage occurs through apoptosis.

Animals↗

PubMed2001

Epidemiological study of pathogenic fungi in China: 1986 and 1996.

OBJECTIVE: An annual decade epidemiological survey of pathogenic fungi of inpatients or outpatients includes more than 25 provinces in China has been done in 1986 and 1996. METHODS: In 1986, there were a total of 9096 strains of pathogenic fungi collected from more than 41 units of 25 provinces in China. 10 years late, 18,085 strains of pathogenic fungi from 41 units of 25 provinces were collected from January 1st to December 31st in 1996. RESULTS: The results showed that during this decade the prominent pathogenic fungus was Trichophyton rubrum, but its ratio gradually decreased. On the contrary, Candida albicans gradually increased in its ratio from 5th in 1986 to 2nd in 1996. CONCLUSION: The pathogenic fungi in China have changed greatly in the past decade from 1986 to 1996.

Candida albicans↗

PubMed2001

Placental leptin correlates with intrauterine fetal growth and development.

OBJECTIVE: To study the role of placental leptin in intrauterine cord leptin production and its relationship with neonatal anthropometry. METHODS: Forty women and their babies (40) were enrolled in this study. Placental tissues were assayed for leptin mRNA by reverse transcription/polymerase chain reaction (RT/PCR), and assayed for the obese gene protein leptin by Western-blot and immunohistochemistry. Blood was taken from the umbilical cord of the babies at delivery. Serum leptin was measured by radio-immunoassay. Neonatal anthropometric measurements were recorded within 48 hours after delivery. Linear regression analysis was used to explore the relationship between placental leptin, cord leptin and neonatal anthropometric measures. RESULTS: The obese gene was expressed in placental tissue at comparable or greater levels than that in adipose tissue. The placentas of the small for gestational age (SGA) neonates expressed leptin mRNA and protein at significantly lower levels than those of the appropriate for gestational age (AGA) neonates (P = 0.0034 and 0.0076), while the placentas of the large for gestational age (LGA) neonates expressed leptin mRNA and protein at significantly higher levels than those of the AGA neonates (P = 0.043 and 0.021). Linear regression analysis showed placental ob gene transcription and leptin translation correlated significantly with cord leptin (r = 0.39 and 0.43), and neonatal Ponderal Index (r = 0.66 and 0.69). CONCLUSION: The placenta provides a source of leptin for the growing fetus, and this placental leptin might be a growth factor in intrauterine fetal development.

Blotting, Western↗

PubMed2001

[Finite element analysis of pulsatile flow in aortic arch].

The blood flows in the ascending aorta and the aortic arch are studied. The theoretical models, boundary conditions and calculation conditions are proposed. The numerical simulation with finite element method of the blood flow in aortic arch of dogs is carried out according to the physiologically pulsatile flow conditions. The calculation results are analyzed with scientific visualization method.

Animals↗

PubMed2001

Early changes of arginine vasopressin and angiotensin II in patients with acute cerebral injury.

OBJECTIVE: To study the changes and clinical significance of arginine vasopressin (AVP) and angiotensin II (AT-II) in patients with acute moderate and severe cerebral injury. METHODS: The early plasma concentration was checked by radioimmunoassay in 47 cases of acute moderate and severe cerebral injury, 30 cases of non-cerebral injury and 30 healthy volunteers. RESULTS: The early plasma concentrations of AVP (50.23 ng/L +/- 15.31 ng/L) and AT-II (248.18 ng/L +/- 82.47 ng/L) in cerebral injury group were higher than those in non-cerebral injury group (AVP for 30.91 ng/L +/- 11.48 ng/L and AT-II for 120.67 ng/L +/- 42.49 ng/L, P<0.01). The early plasma concentrations of AVP and AT-II in cerebral injury group were also obviously higher than those of the volunteers (AVP for 5.16 ng/L +/- 4.23 ng/L and AT-II for 43.11 ng/L +/- 16.39 ng /L, P<0.001). At the same time, the early plasma level of AVP (58.90 ng/L +/- 18.12 ng/L) and AT-II (292.13 ng/L +/- 101.17 ng/ L) was higher in severe cerebral injured patients than moderate cerebral injured ones (AVP for 36.68 ng/L +/- 12.16 ng/L and AT-II for 201.42 ng/L +/- 66.10 ng/L, P<0.01). The early level of AVP and AT-II was negatively related to the GCS scales in acute cerebral injury. The early plasma concentrations of AVP (45.98 ng/L +/- 13.48 ng/L) and AT-II (263. 28 ng/L +/- 80.23 ng/L) were lower in epidural hematoma group than those of subdural hematoma and cerebral injury group (AVP for 64.12 ng/L +/- 15.56 ng /L and AT-II for 319.82 ng/L +/- 108.11 ng/L, P<0. 01). CONCLUSIONS: AVP and AT-II may play an important role in pathophysiologic process in the secondary cerebral injury. The more severe the cerebral injury is, the higher the early level of AVP and AT-II will be. The early plasma level of AVP and AT-II may be one of the severity indexes of cerebral injury.

Acute Disease↗

PubMed2001

[Profile of telomerase and telomerase RNA expression in nasopharyngeal carcinogenesis of rats induced by N, N'dinitrosopiperazine (DNP)].

OBJECTIVE: To investigate the profile of telomerase and telomerase RNA expression in nasopharyngeal carcinogenesis (NPC) induced by N, N'dinitrosopiperazine (DNP) and examined histolofically. METHODS: Nasopharyngeal carcinomas of rats were induced by DNP and examined histologically. PCR-ELISA and nested RT-PCR were used to assay telomerase and telomerase RNA expression at different stages in the nasopharyngeal tissues of rats. RESULTS: During the carcinogenesis process, telomerase activity increased along with the formation of a nasopharyngeal carcinoma. Telomerase expression was positively related with nasopharyngeal carcinogenesis. Telomerase RNA expression was present and did not change during the NPC process. Expression of telomease RNA was earlier than telomerase activation. Telomerase activation and telomerase RNA expressin were also detected in the pre-cancerous nasopharyngeal lesions. CONCLUSION: Telomerase activation may participate in the onset and progression of NPC, and is an early step in NPC.

Animals↗

PubMed2001

[Studies on the methods of mating test for Cryptococcus neoformans].

Six media (MA:Mating agar, HA:Hay agar, HCA:Hay cube agar, RSA:Rice shell agar, IHA:additional nutrition in HA and SDA:Sabouraudia dextrose agar) were compared for their efficiencies of the mating test for Cryptococcus neoformans. The positive rates in 2-week-cultivation were 95% (HCA and RSA), 86% (HA), 38% (MA and SDA) and 24% (IHA). The streaking inoculation was equally replaced by the dot inoculation for the mating tests. However, the dot method saves much more materials, and is suitable for testing in large number of isolates. Additionally, the precultivation of the tester and tested isolates in broth medium (YMPDB) could enhance the positive mating rates.

Agar↗

PubMed2000

Serum cholesterol levels in paranoid and non-paranoid schizophrenia associated with physical violence or suicide attempts in Taiwanese.

A review of medical charts over a 1-year period was carried out in a population of 213 Taiwanese psychiatric inpatients that included 106 patients with schizophrenia. In subgroup analyses within the group of patients with schizophrenia, no significant differences in serum cholesterol levels were found between paranoid and non-paranoid schizophrenic patients, between patients with and without physical violence, or between patients who had and had not made a suicide attempt.

Adult↗

PubMed2000

Structure of the protease domain of memapsin 2 (beta-secretase) complexed with inhibitor.

Memapsin 2 (beta-secretase) is a membrane-associated aspartic protease involved in the production of beta-amyloid peptide in Alzheimer's disease and is a major target for drug design. We determined the crystal structure of the protease domain of human memapsin 2 complexed to an eight-residue inhibitor at 1.9 angstrom resolution. The active site of memapsin 2 is more open and less hydrophobic than that of other human aspartic proteases. The subsite locations from S4 to S2' are well defined. A kink of the inhibitor chain at P2' and the change of chain direction of P3' and P4' may be mimicked to provide inhibitor selectivity.

Amyloid Precursor Protein Secretases↗

PubMed2000

Construction and immunogenicity in mice of attenuated Salmonella typhi expressing Plasmodium falciparum merozoite surface protein 1 (MSP-1) fused to tetanus toxin fragment C.

One strategy to develop a multi-antigen malaria vaccine is to employ live vectors to carry putative protective Plasmodium falciparum antigens to the immune system. The 19 kDa carboxyl terminus of P. falciparum merozoite surface protein 1 (MSP-1), which is essential for erythrocyte invasion and is a leading antigen for inclusion in a multivalent malaria vaccine, was genetically fused to fragment C of tetanus toxin and expressed within attenuated Salmonella typhi CVD 908. Under conditions in the bacterial cytoplasm, the fragment C-MSP-1 fusion did not form the epidermal growth factor (EGF)-like domains of MSP-1; monoclonal antibodies failed to recognize these conformational domains in immunoblots of non-denatured protein extracted from live vector sonicates. The MSP-1 was nevertheless immunogenic. One month following intranasal immunization of BALB/c mice with the live vector construct, four out of five mice exhibited > or =four-fold rises in anti-MSP-1 by ELISA (GMT=211); a single intranasal booster raised titers further (GMT=1280). Post-immunization sera recognized native MSP-1 on merozoites as determined by indirect immunofluorescence. These data encourage efforts to optimize MSP-1 expression in S. typhi (e.g. as a secreted protein), so that the EGF-like epitopes, presumably necessary for stimulating protective antibodies, can form.

Animals↗

PubMed2000

p55CDC/hCDC20 is associated with BUBR1 and may be a downstream target of the spindle checkpoint kinase.

Eukaryotic cells have evolved a mechanism that delays the progression of mitosis until condensed chromosomes are properly positioned on the mitotic spindle. We have been studying genes that regulated the spindle checkpoint in human cells. Enforced expression of human BUBR1, but not a BUBR1 mutant allele, enhances accumulation of mitotic cells. Yeast two-hybrid system and GST-pulldown analyses show that p55CDC/hCdc20, a protein known to link spindle checkpoint components such as MAD2 to anaphase promoting complex (APC), interacts with BUBR1. In addition, p55CDC is capable of pulling down BUBR1 in sf-9 cells infected with both p55CDC and His6-BUBR1 recombinant baculoviruses but not in the cells infected with p55CDC baculoviruses or with the baculoviral vector alone. Moreover, immunoprecipitation followed by Western blot analyses confirmed that native p55CDC is associated with BUBR1 in HeLa cells. Spindle checkpoint activation by nocodazole treatment enhances the association between p55CDC and His6-BUBR1. In nocodazole-arrested mitotic cells, both CDC16 and hyperphosphorylated CDC27, two APC components, preferentially associate with His6-BUBR1 resins, but not the control resins. Furthermore, BUBR1 phosphorylates p55CDC in vitro, and the phosphorylation of p55CDC by BUBR1 appears to be correlated with spindle checkpoint activation. Together, our studies strongly suggest that BUBR1 may target APC via p55CDC.

Alleles↗

PubMed2000

Attractive through-space S-O interaction in the DNA-cleaving antitumor antibiotic leinamycin.

We describe here a study on the intramolecular nonbonded 1, 5-sulfur-oxygen (S-O) interaction in the antitumor antibiotic leinamycin 1. The results from density-functional theoretical and semiempirical calculations on leinamycin 1 and model systems 2-5 provide evidence for the 1,5-S-O nonbonded interaction. Our results are used to explain previous experimental data on the X-ray structure of leinamycin 1 (Hirayama, N.; Matsuzawa, E. S. Chem. Lett. 1993, 1957). The amide oxygen (O5) alters the thiosulfinate ester conformation and stabilizes the 1,2-dithiolan-3-one 1-oxide heterocycle. The attractive interaction induces S1 of leinamycin to adopt a distorted trigonal bipyramidal geometry. The magnitude of this stabilizing interaction is approximately 6 kcal/mol.

Antibiotics, Antineoplastic↗