Biomedical subjects

L Zou

Publications and source records attributed to L Zou.

At least 37 records · Page 2Linked to original sources

PubMed2001

Tooth size and morphology in twins.

OBJECTIVE: To assess concordance of tooth size and occlusal morphology in monozygotic (identical) and dizygotic (non-identical) twins compared to unrelated controls in order to determine how much these dental traits are related to inheritance. METHODS: Mesiodistal and bucco-lingual dimensions of tooth size in 34 pairs of twins were measured with dial calipers. In addition, the occlusal morphology of nine pairs of teeth was assessed using a co-ordinate measuring machine with a non-contact laser probe. RESULTS: The results showed greater concordance in tooth size for both mesiodistal and bucco-lingual dimensions within twin pairs compared to twin and unrelated controls. Furthermore, monozygotic (MZ) twins showed greater concordance than dizygotic (DZ) twins for all permanent teeth with statistically significant variance for the mesiodistal dimension (P = 0.01) but not bucco-lingual dimension. Superimposed computer models of the digitized occlusal surfaces showed a high degree of similarity for MZ twins compared to DZ twins. The mean intrapair deviation was 147 microm for MZ, 209 microm for DZ and 258 microm for unrelated controls. CONCLUSIONS: The remarkable similarity in the tooth size and morphology of monozygotic twins suggests a strong inheritability factor to tooth size and shape and that these may be useful as additional tools for zygosity determination along with other dental traits.

Adolescent↗

PubMed2001

[The influence of ecological factors on simultaneous nitrification and denitrification in MBR].

The influence of dissolved oxygen(DO), C/N and pH on simultaneous nitrification and denitrification in the membrane bioreactor was studied. The experimental results showed that only under condition that each ecological factor was maintained relative steady, simultaneous nitrification and denitrification might proceed smoothly. When DO, C/N and pH of feed water was 1 mg/L, 30 and 7.2, the removal rate of COD, NH4+, and TN were 96%, 95% and 92% respectively.

Bioreactors↗

PubMed2001

[beta-elemene induces apoptosis of K562 leukemia cells].

OBJECTIVE: To investigate the apoptosis-inducing effect of beta-elemene on K562 leukemia cells. METHODS: Hoechst 33342 and PI fluorescence staining, DNA fragmentation, electron microscopy, flow cytometry, and immunocytochemistry were used to evaluate the effect of beta-elemene on K562 cells. RESULTS: beta-elemene heatment induced the formation of apoptotic bodies and DNA ladder. The effect was dose- and time-dependent. The expression of bcl-2 was decreased in beta-elemene treated cells as compared with the untreated control cells. CONCLUSION: beta-elemene exerts its cytotoxic effect on K562 leukemic cells by the induction of apoptosis.

Apoptosis↗

PubMed2001

[The development of clinical application of the rejuvenator and a study of its mechanism for the treatment of functional erectile dysfunction].

In this paper, we describe the development and clinical application of the Rejuvenator and report the result of our study on its mechanism for the treatment of functional erectile dysfunction (FED). The Rejuvenator, which can be used both at home and in hospitals to treat patients with FED, was developed on the basis of our clinical practice in the light of the modern theory of traditional Chinese medicine and by integrating multiple techniques of engineering science. It works by means of the paraoral use of the special herbal medicine, electro-magnetic effects, thermal moxibustion and drug-ingression. 2250 patients with FED received the treatment. Using combined electro-neurophysiological techniques, pulsed ultrasound Doppler and microcomputer image-scanning, we further studied the mechanism of the Rejuvenator for the treatment of FED. The total effective rate was 92%. The clinical data and result of study indicate that the Rejuvenator for the patients with functional erectile dysfunction is a safe, effective and scientific new method.

Adult↗

PubMed2001

[Orthokeratology induced infective corneal ulcer].

OBJECTIVE: To investigate the clinical course, treatment and outcome of infective corneal ulcer induced by orthokeratology. METHODS: Sixteen cases of infective corneal ulcer caused by orthokeratology were reported, including 7 cases of pseudomonas corneal ulcers, 8 cases of acanthamoeba keratitis and 1 case of mycotic keratitis. Smears and cultures from corneal scrapings for bacteria, fungi and amoeba were performed for all of the patients. According to the results of pathogenic microorganisms, different therapeutic approaches were given. Lamellar keratoplasty or penetrating keratoplasty was performed for 9 patients whose corneal lesions were serious and unresponsive to medical therapy. RESULTS: After medical treatment or keratoplasty, corneal infections of all the patients were controlled. The visual acuity of most cases was improved. CONCLUSIONS: The infective corneal ulcer is the most serious complication of orthokeratology. The treatment of infective corneal ulcer should be directed toward the elimination of the pathogenic microorganisms from the cornea. Keratoplasty continues to have a central role in the management of some advanced cases. Although the infections can be controlled, the vision of these patients is seriously damaged.

Acanthamoeba Keratitis↗

PubMed2001

[An experimental study on subconjunctival interleukin-1 receptor antagonist for promotion of corneal transplant survival].

OBJECTIVE: To determine whether the subconjunctival application of interleukin-1 receptor antagonist (IL-1ra) can prolong the corneal graft survival in the rat model of orthotopic penetrating keratoplasty. METHODS: For all experiments, F344 corneas were transplanted into LOU (major histocompatibility-disparate) eyes. Experimental groups received subconjunctival injection of 50, 100 and 200 microg IL-1ra respectively, and the control group received the same volume of 0.9% normal saline instead for consecutive 2 weeks. All transplants were evaluated for 4 weeks after surgery for signs of rejection. RESULTS: The mean survival time (MST) of the grafts of the experimental groups was increased significantly (t = 0.00, P < 0.01) in comparison with the control group. The MST of the IL-1ra 200 microg group was increased significantly than that of the IL-1ra 50 microg group (t = 0.00, P < 0.01). Furthermore, the IL-1ra-treated grafts had significantly less corneal inflammation, infiltration, lower levels of opacity, edema, neovascularization and rejection index compared with the control group. CONCLUSIONS: Subconjunctival treatment of IL-1ra has a significantly positive effect on promoting corneal allograft survival. And its effect is dosage-dependent.

Animals↗

PubMed2001

[Study on the chemosensitivity test of human gastric cancer using the MTT assay].

OBJECTIVE: This study was conducted to investigate the chemosensitivity of gastric carcinoma. METHODS: 112 cases of fresh human gastric cancer samples were obtained for drug sensitivity testing using MTT. RESULTS: The sensitivity sequence of antitumor agents was 5-Fu, DDP, MMC, etc. On the other hand, the sensitivity was relative to pathology and individual differences. CONCLUSION: The MTT assay is an accurate system for determination of the chemosensitivity of tumor cells.

Adenocarcinoma↗

PubMed2000

Human hyaluronidases: electrophoretic multiple forms in somatic tissues and body fluids. Evidence for conserved hyaluronidase potential N-glycosylation sites in different mammalian species.

Some properties of the multiple forms of human hyaluronidases in somatic tissues and in body fluids were investigated. Liver and placenta exhibited seven hyaluronidase forms when analyzed electrophoretically on a polyacrylamide-hyaluronan gel. Ovary, breast, myometrium, endometrium, skin, leukocytes and platelets displayed distinct patterns of enzymatic micropolydispersity. The most acidic forms of hyaluronidase were in synovial fluid and serum, some serum exhibited an additional basic form. Following sialidase treatment, the number of forms decreased to two in placenta, three in liver and to a broad basic form in serum. The native serum and placental hyaluronidases remained fully active after thermal inactivation but desialylated hyaluronidase was inactivated slowly in serum, and quickly in placenta suggesting a higher overall glycosylation of the plasma enzyme. Potential N-glycosylation sites were searched in the amino acid sequences of six human hyaluronidases and several hyaluronidases from different mammalian species using the PROSITE motif database. A potential N-glycosylation site (site 1) with similar tripeptide patterns was observed at the same position in human plasma (HYAL1), human lysosomes (HYAL2) and in two newly reported hyaluronidases (HYAL4 and HYALP1). The same site was also present in mouse plasma (HYAL1) and mouse lysosomes (HYAL2), and in rat lysosomes (HYAL2). This site was absent in human HYAL3 and in all sperm hyaluronidases (PH-20) studied (human, macaque, mouse, guinea pig, rabbit and fox). A second potential N-glycosylation site was observed at a location further in the polypeptide chain. This site is present in all mammalian hyaluronidase isoenzymes reported in the present study whatever the species and organ localization. The pattern at site 2 is NVT for all hyaluronidases except for hyaluronidases of lysosomal origin where it is NVS. Such conserved sites strongly suggest that they may represent actual N-glycosylation sites.

Animals↗

PubMed2000

The human ARHI tumor suppressor gene inhibits lactation and growth in transgenic mice.

ARHI is a novel imprinted tumor suppressor gene. To study its function in vivo, we have developed transgenic mice that overexpress ARHI. Offspring bearing the transgene had significantly lower body weights than did nontransgenic littermates. In addition, strong expression of the ARHI transgene was associated with greatly impaired mammary gland development and lactation, failure of ovarian folliculogenesis resulting in decreased fertility, loss of neurons in the cerebellar cortex, and impaired development of the thymus. Decrease in body size and defects in the mammary glands correlated with the level of transgene expression. Immunohistochemical analysis indicated that expression of prolactin (PRL), but not growth hormone, was lower in the pituitary glands of mice with defective mammary gland development. The defect in pregnancy-associated mammary tissue proliferation was associated with decreased serum PRL and progesterone levels. Moreover, lower levels of estrogen receptor and progesterone receptor were observed in postpartum mammary glands and in the ovaries of mice that overexpressed ARHI. Our data suggest that ARHI can inhibit PRL secretion and act as a negative regulator in murine growth and development.

Animals↗

PubMed2000

Experimental examination of the effects of atmospheric wet deposition on primary production in the Yellow Sea.

The effects of atmospheric wet deposition on primary production in the coastal Yellow Sea were examined by in situ incubation experiments in August, 1997. Phytoplankton species flourished in response to nutrient additions and chlorophyll-a (Chl-a) increased significantly when rainwater was added. Concentration of Chl-a increased 2.6 times with the addition of 10% (v/v) rainwater. In a coastal eutrophic region like Jiaozhou Bay, the impact of atmospheric wet deposition is negligible. However, the N/P ratio ranged from 22:1 to 80:1, indicating P limitation of photosynthesis in the Yellow Sea. During field observations, high N and low P rainwater was observed to be transported into the oligotrophic central Yellow Sea. Ammonium was used by phytoplankton in preference to nitrate, and Fe stimulated nutrient uptake by phytoplankton. Rainwater increased the Chl-a growth more than a single nutrient owing to the abundance of both plant and trace nutrients in the rainwater. A negative exponent relationship may exist between the impact of rainwater and total nutrient quality of the water in influencing phytoplankton growth.

Journal Article↗

PubMed2000

Pramipexole inhibits lipid peroxidation and reduces injury in the substantia nigra induced by the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in C57BL/6 mice.

Pramipexole has been showed to protect cultured dopaminergic (DAergic) cells against free radical-induced cytotoxicity. To test if pramipexole is protective against 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP)-mediated nigral DAergic injury in vivo and if such protection is related to inhibition of lipid peroxidation, DAergic function and lipid peroxidation were determined in MPTP-treated C57BL/6 mice. We reported that MPTP administration induced a 38.1% increase of lipid peroxidation product thiobarbituric acid reactive substance (TBARS) in nigra, a 46.7% decrease of tyrosine hydroxylase -positive nigral DAergic neurons and a 59.4% reduction of striatal DA levels. However, pramipexole treatment significantly inhibited the TBARS production by 76%, and attenuated the MPTP-induced decreases in nigral DAergic neurons and striatal DA levels by about 50%. This study suggests that pramipexole can inhibit free radical-mediated lipid peroxidation and protect MPTP-induced nigral injury.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed2000

Using electrophoresis to observe the interaction of nitrogenase with ions.

The two protein components of nitrogenase from Klebsiella pneumoniae were shown to interact with metal ions and ADP, altering their electrophoretic mobility in polyacrylamide gel electrophoresis. Both Mg+2 and Mn+2 caused reduced mobility of Fe protein relative to other proteins. The effect was about 50% complete at concentrations around 0.2 mM. Other ions including Fe+2, Ni+2 and Co+2 had no observable effect at levels up to 1 _mM. Both Cd+2 and Zn+2 appeared to interact with the protein; Cd+2 at 0.5 mM dramatically destabilized the protein. The effects of more than a dozen different mutations of the Fe protein on Mg+2 interaction were examined. All mutated proteins appeared to interact with Mg+2 similarly to wild-type. Using relative mobility differences of charge-changed mutants it was estimated that two to three Mg+2 interact with each Fe protein monomer. The MoFe protein also showed interaction with metal ions but the alteration of mobility was much smaller than for the Fe protein because it is larger and less acidic, so that it runs much more slowly than the Fe protein in standard gels. The interaction of ADP with Fe protein was examined in the presence of Mg+2. Increasing ADP partially reversed the mobility decrease observed on Mg+2 binding, and produced a more diffuse protein band indicative of a reaction zone of interconverting conformers. No alteration of MoFe protein mobility was observed with ADP added during electrophoresis.

Adenosine Diphosphate↗

PubMed2000

Prolonged transgene expression mediated by a helper-dependent adenoviral vector (hdAd) in the central nervous system.

Conventional adenoviral vectors such as E1-deleted first-generation adenovirus (fgAd) elicit striking host immune response, resulting in limited expression of the transgene. A recently described helper-dependent, or gutless, adenoviral vector (hdAd) can promote stable transgene expression in peripheral organs, including the liver. We therefore investigated the safety and durability of hdAd-mediated gene transfer to the central nervous system (CNS) of rats compared with gene delivery by fgAd. Equal amounts of either fgAd or hdAd carrying the beta geo transgene were stereotactically injected into the right hippocampus of adult rats. Transgene expression was assessed by histochemical staining, transgene stability by PCR analysis, and immune infiltration of T lymphocytes and macrophages by immunocytochemical methods. Strong transgene expression from either vector was detected in brain tissue examined on day 6 postinoculation. Thereafter, fgAd-mediated gene expression rapidly decreased, becoming undetectable by day 66, while expression from the hdAd vector persisted throughout the test period. PCR confirmed the presence of hdAd-associated DNA at 66 days postinoculation. The hdAd injection elicited apparently lower numbers of brain-infiltrating macrophages and T cells than did administration of fgAd. These results indicate improved transgene expression and reduced immunogenicity with use of hdAd to deliver genes to the CNS.

Adenoviridae↗

PubMed2000

Isolation of fetal nucleated red blood cells from maternal blood.

To find a simple, effective method of isolating fetal cells from maternal peripheral blood for prenatal diagnosis, 45 women were studied with their gestation being 6-14 weeks and age 21-30 years. The fetal cells were isolated from maternal blood by using discontinuous density gradient centrifugation. Some of the isolated cells were made smear and counted under the microscope; others were used for predicting fetal sex by PCR amplification of Y chromosome specific DYZ1 gene. The major cells in the upper separation interface were lymphocytes and monocytes, with occasionally seen nucleated red blood cells (NRBC); while those in the middle separation interface were neutrocytes, with NRBC scattering. The ratio of NRBC/nucleated cells was 1.98 +/- 0.28 x 10(-5). There was no significant difference between the first and second trimester (P > 0.05). The amount of isolated fetal cells was sufficient for prenatal genetic diagnosis. Male pregnancy was correctly predicted in 10 out of 13 cases. It is concluded that the method of discontinuous density gradient centrifugation was of considerable importance in the development of non-invasive prenatal genetic diagnosis.

Adult↗

PubMed2000

Effect of nitrite on endothelial function in isolated lung.

Nitrated tyrosine, implicated in protein dysfunction, is increased in various tissues in association with diverse pathological processes. Angiotensin converting enzyme (ACE) is a luminal vascular endothelial enzyme whose dysfunction is an early sign of endothelial injury. ACE contains a tyrosine critical for its enzymatic activity. Others have shown that nitrite exacerbates the ACE dysfunction of cultured endothelial cells in contact with activated polymorphonuclear neutrophils (PMN). We hypothesized that exogenous nitrite would enhance endothelial ACE dysfunction associated with PMN activation in the isolated lung. Rats received lipopolysaccharide (LPS) 2 h prior to isolated lung perfusion with Ficoll containing buffer. Either formyl-Met-Leu-Phe (fMLP, 10(-7) M) or phorbol myristate acetate (PMA, 10(-7) M) was used to activate PMN in lungs treated or not treated with 300-microM nitrite. A first pass indicator dilution method and first order reaction kinetics were used to determine ACE activity, while lung Ficoll content served as an index of vascular permeability. Both fMLP and PMA decreased endothelial ACE activity and increased pulmonary artery pressure, edema and vascular permeability. Exogenous nitrate did not potentiate the decrease in ACE activity, the lung injury or nitrotyrosine immunoreactivity of lung homogenates. In contrast to observations in cultured endothelial cells, our findings in the whole lung are compatible with the speculation of others that the rat lung has an unidentified factor, which minimizes accumulation of nitrated proteins.

Animals↗

PubMed2000

Interaction with magnesium and ADP stabilizes both components of nitrogenase from Klebsiella pneumoniae against urea denaturation.

The nitrogenase enzyme of Klebsiella pneumoniae consists of two separable proteins, each with multiple subunits and one or more oxygen sensitive metallocenters. The wild-type nitrogenase proteins are stable to electrophoresis in high concentrations of urea under anaerobic conditions. Addition of Mg+2 and ADP greatly increases the stability of the smaller Fe protein (from <4 to >6 M for full unfolding), an effect directly analogous to stabilization in p21ras induced by Mg+2 and GDP. Stabilization by Mg+2 is slight for the holo MoFe protein (from approximately 1.5 to approximately 2.4 M) but more dramatic for the apo protein form of the MoFe protein accumulated by certain Fe protein (nifH gene) mutants. The potent product inhibitor of nitrogenase function, MgADP, increases stability of the MoFe protein more than Mg+2 alone, to approximately 3.6 M, showing that nucleotides interact with the MoFe protein. Mutations of the nifM gene result in slower accumulation of less stable Fe protein, indicating that NifM is involved in correct folding of the Fe protein. Mutationally altered proteins are often difficult to purify for study because of their inherent instability, low expression level, or oxygen lability. Crude extracts of 11 different mutants of Fe protein (nifH gene) were examined by transverse urea gradient gels to rapidly screen for stabilizing interactions in the presence or absence of substrate or inhibitor analogs. Amino acid alterations D44N and R188C, at the interface of the dimer, in the vicinity of the nucleotide binding site(s), have significantly lower stability than the wild-type enzyme in the absence of Mg+2 but comparable stability in its presence, showing the importance of Mg+2 in the subunit interactions. Mutations N163S and E266K, in which residues normally involved in hydrogen bonding far from the active site were altered, are more labile than the wild-type even with Mg+2 added. Seven other mutants, though nonfunctional, did not appear altered in stability compared to the wild-type.

Adenosine Diphosphate↗

PubMed2000

Assembly of a complex containing Cdc45p, replication protein A, and Mcm2p at replication origins controlled by S-phase cyclin-dependent kinases and Cdc7p-Dbf4p kinase.

In Saccharomyces cerevisiae, replication origins are activated with characteristic timing during S phase. S-phase cyclin-dependent kinases (S-CDKs) and Cdc7p-Dbf4p kinase are required for origin activation throughout S phase. The activation of S-CDKs leads to association of Cdc45p with chromatin, raising the possibility that Cdc45p defines the assembly of a new complex at each origin. Here we show that both Cdc45p and replication protein A (RPA) bind to Mcm2p at the G(1)-S transition in an S-CDK-dependent manner. During S phase, Cdc45p associates with different replication origins at specific times. The origin associations of Cdc45p and RPA are mutually dependent, and both S-CDKs and Cdc7p-Dbf4p are required for efficient binding of Cdc45p to origins. These findings suggest that S-CDKs and Cdc7p-Dbf4p promote loading of Cdc45p and RPA onto a preformed prereplication complex at each origin with preprogrammed timing. The ARS1 association of Mcm2p, but not that of the origin recognition complex, is diminished by disruption of the B2 element of ARS1, a potential origin DNA-unwinding element. Cdc45p is required for recruiting DNA polymerase alpha onto chromatin, and it associates with Mcm2p, RPA, and DNA polymerase epsilon only during S phase. These results suggest that the complex containing Cdc45p, RPA, and MCMs is involved in origin unwinding and assembly of replication forks at each origin.

Carrier Proteins↗

PubMed2000

[Evaluation of derma and fat combined pedicled superficial temporal fascia flap for reconstruction of facial depression].

OBJECTIVE: To evaluate the curative effect of derma and fat combined pedicled superficial temporal fascia flap for reconstruction of facial depression. METHOD: Postoperative follow-up and comparative study were performed. 10 cases of facial depression deformities were involved, in which 5 cases were hemifacial atrophy, and 5 cases were branchial arch maldevelopment. RESULTS: Postoperative follow-up for 1-3 years showed that the method produced better results in branchial arch depression than in hemifacial atrophy. The combined tissue used in plomb of branchial arch maldevelopment had a low ratio of anaphase absorption, maintaining a satisfactory long-term full contour. In plomb of hemifacial atrophy, the anaphase absorption ratio of the was combined tissue approximately 20%-40%. CONCLUSIONS: The noxa of depression ought to be noticed when this method is used in reconstruction of facial depression. The exorbitant plomb is inadvisable for facial depression of branchial arch maldevelopment. However, in facial depression of hemifacial atrophy, in considering anaphases absorption, the suitable exorbitant plomb is reasonable for better future results.

Adolescent↗