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Biomedical subjects

C Zhu

Publications and source records attributed to C Zhu.

At least 55 records · Page 3Linked to original sources
PubMed2001

Expression of matrix metalloproteinase-2, -9, -14, and tissue inhibitors of metalloproteinase-1, -2, -3 in the endometrium and placenta of rhesus monkey (Macaca mulatta) during early pregnancy.

The extracellular matrix proteolytic machinery has long been recognized as one of the most important mechanisms for regulating trophoblast invasion. Matrix metalloproteinases (MMPs) are a group of proteases involved in this process, and their activities are regulated by tissue inhibitors of MMPs (TIMPs). In this study, we collected rhesus monkey uteri on Days 12, 18, and 26 of pregnancy and examined the mRNA expression of MMP-2, -9, -14, and TIMP-1, -2, -3, as well as the activities of MMP-2 and -9 by using in situ hybridization and gelatin zymography, respectively. The results showed that MMP-2 and -9 were expressed earlier than MMP-14 and TIMPs in the pregnant endometrium. MMP-14 and TIMP-2 mRNAs appeared in perivascular decidual cells earlier than MMP-2 mRNA. On Day 26 of pregnancy, placental villi expressed little MMP-2, -14, and TIMP transcripts but abundant MMP-9 mRNA. Furthermore, MMP-2, -9, -14, and TIMP-1, -2, -3 were highly expressed on the fetal-maternal border but were absent in the myometrium. TIMP-3 mRNA in the endometrium was specifically localized to some cells lining the outer membrane of several groups of arterioles. Combined with the results obtained by gelatin zymography, we found that active MMP-2 existed in the endometrium throughout these three phases, while MMP-9 showed considerable activities only on Days 18 and 26 of pregnancy. The data suggest key roles for MMP-2 and -9 in invasion of trophoblast cells into the endometrium and the development of the placenta and might indicate that these processes are regulated by MMP-14 and TIMP-1, -2, and -3.

Animals↗
PubMed2001

Kinetic measurements of cell surface E-selectin/carbohydrate ligand interactions.

Selectin/ligand interactions initiate the multistep adhesion and signaling cascades in the recruitment of leukocytes from circulation to inflamed tissues and may also play a role in tumor metastasis. Kinetic properties of these interactions are essential determinants governing blood-borne cells' tethering to and rolling on the vessel wall. Extending our recently developed micropipette method, we have measured the kinetic rates of E-selectin/ligand interactions. Red cells coated with an E-selectin construct were allowed to bind HL-60 or Colo-205 cells bearing carbohydrate ligands. Specific adhesions were observed to occur at isolated points, the frequency of which followed a Poisson distribution. These point attachments were formed at the same rate with both the HL-60 and Colo-205 cells (0.14 +/- 0.04 and 0.13 +/- 0.03 microm2 s(-2) per unit density of E-selectin, respectively) but dissociated from the former at a rate twice as fast as did from the latter (0.92 +/- 0.23 and 0.44 +/- 0.10 s(-1), respectively). The reverse rates agree well with those measured by the flow chamber. The forward rates are orders of magnitude higher than those of Fcgamma receptors interacting with IgG measured under similar conditions, consistent with the rapid kinetics requirement for the function of E-selectin/ligand binding, which is to capture leukocytes on endothelial surfaces from flow.

Animals↗
PubMed2001

Complete nucleotide sequence and analysis of the locus of enterocyte Effacement from rabbit diarrheagenic Escherichia coli RDEC-1.

The pathogenicity island termed the locus of enterocyte effacement (LEE) is found in diverse attaching and effacing pathogens associated with diarrhea in humans and other animal species. To explore the relation of variation in LEE sequences to host specificity and genetic lineage, we determined the nucleotide sequence of the LEE region from a rabbit diarrheagenic Escherichia coli strain RDEC-1 (O15:H-) and compared it with those from human enteropathogenic E. coli (EPEC, O127:H6) and enterohemorrhagic E. coli (EHEC, O157:H7) strains. Differing from EPEC and EHEC LEEs, the RDEC-1 LEE is not inserted at selC and is flanked by an IS2 element and the lifA toxin gene. The RDEC-1 LEE contains a core region of 40 open reading frames, all of which are shared with the LEE of EPEC and EHEC. orf3 and the ERIC (enteric repetitive intergenic consensus) sequence present in the LEEs of EHEC and EPEC are absent from the RDEC-1 LEE. The predicted promoters of LEE1, LEE2, LEE3, tir, and LEE4 operons are highly conserved among the LEEs, although the upstream regions varied considerably for tir and the crucial LEE1 promoter, suggesting differences in regulation. Among the shared genes, high homology (>95% identity) between the RDEC-1 and the EPEC and EHEC LEEs at the predicted amino acid level was observed for the components of the type III secretion apparatus, the Ces chaperones, and the Ler regulator. In contrast, more divergence (66 to 88% identity) was observed in genes encoding proteins involved in host interaction, such as intimin (Eae) and the secreted proteins (Tir and Esps). A comparison of the highly variable genes from RDEC-1 with those from a number of attaching and effacing pathogens infecting different species and of different evolutionary lineages was performed. Although RDEC-1 diverges from some human-infecting EPEC and EHEC, most of the variation observed appeared to be due to evolutionary lineage rather than host specificity. Therefore, much of the observed hypervariability in genes involved in pathogenesis may not represent specific adaptation to different host species.

Amino Acid Sequence↗
PubMed2001

Induction and characterization of neutralizing antibodies against a human immunodeficiency virus type 1 primary isolate.

Chimpanzees infected with the primary isolate DH012 mount potent neutralizing antibodies. This DH012 neutralizing activity is highly strain specific. Immune sera from guinea pigs immunized with recombinant DH012 gp120 could also neutralize this primary isolate. The neutralizing activity in chimpanzee and guinea pig sera against wild-type DH012 appears to be independent of a linear epitope in the V3 region of gp120. Interestingly, the neutralization escape mutant derived from growing DH012 in the presence of the potent neutralizing chimpanzee serum is at least 50-fold more sensitive than wild-type DH012 to neutralization by guinea pig immune sera. The unusually potent neutralizing activity against the DH012 neutralization-resistant virus is due to the presence of anti-V3 antibodies in guinea pig sera. These results suggested that recombinant gp120 could induce neutralizing antibodies against primary isolate DH012. The V3 of wild-type DH012 is poorly immunogenic in infected chimpanzees and is not accessible to neutralizing V3 antibodies. It is likely that this cryptic V3 region became exposed when the virus escaped the neutralizing activity of the chimpanzee serum.

Animals↗
PubMed2001

Identification of self through two-dimensional chemistry and synapses.

Cells in the immune and nervous systems communicate through informational synapses. The two-dimensional chemistry underlying the process of synapse formation is beginning to be explored using fluorescence imaging and mechanical techniques. Early analysis of two-dimensional kinetic rates (k(on) and k(off)) and equilibrium constants (K(d)) provides a number of biological insights. First, there are two regimes for adhesion-one disordered with slow k(on) and the other self-ordered with 10(4)-fold faster k(on). Despite huge variation in two-dimensional k(on), the two-dimensional k(off) is like k(off) in solution, and two-dimensional k(off) is more closely related to intrinsic properties of the interaction than the two-dimensional k(on). Thus difference in k(off) can be used to set signaling thresholds. Early signaling complexes are compartmentalized to generate synergistic signaling domains. Immune antigen receptor components have a role in neural synapse editing. This suggests significant parallels in informational synapse formation based on common two-dimensional chemistry and signaling strategies.

CD4 Antigens↗
PubMed2001

Caspase-3 activation after neonatal rat cerebral hypoxia-ischemia.

Caspase-3 is a major effector protease in several apoptotic pathways, but its role in hypoxic-ischemic (HI) brain injury is incompletely understood. Cerebral HI was induced in 7-day-old rats by unilateral carotid artery ligation and exposure to 7.7% oxygen for 55 min. Caspase-3-like activity was significantly increased at 1 h (208%), peaked at 24 h (2,563%) and was still increased 6 days after HI (169%) in the ipsilateral cerebral cortex. Concomitantly, cleavage of the caspase-3 proform (31/33 kD) was detected on immunoblots, producing 29- and 17-kD fragments. Furthermore, significant degradation of the endogenous caspase-3 substrates inhibitor of caspase-activated DNase (DNA fragmentation factor 45), poly(ADP-ribose) polymerase and fodrin occurred. In conclusion, caspase-3 is activated extensively in the immature brain after HI. The subsequent cleavage of proteins involved in cellular homeostasis and repair may contribute to the process of brain injury.

Animals↗
PubMed2001

The effects of Lei Gong Teng on reproductive hormones.

The serum reproductive hormone levels were examined with radioimmunoassay in women of child-bearing age before and after treatment with the prescriptions containing Lei Gong Teng ([symbol: see text] Radix Tripterygii Wilfordii). The results showed that Lei Gong Teng could induce amenorrhea, but it was reversible.

Adolescent↗
PubMed2001

[A study on city motor vehicle emission factors by tunnel test].

Applying the principle of tunnel test to run a typical across-river tunnel test in Guangzhou city, 48 h-online-monitor data include pollutant concentration, traffic activity and meteorological data were gained. The average motor vehicle emission factors of NOx, CO, SO2, PM10 and HC were calculated using mass balance which are 1.379, 15.404, 0.142, 0.637, 1.857 g/km. vehicle respectively. Based on that, combined emission factors of 8 types of city vehicles were calculated using linear regression. The result basically showed the character and level of motor vehicle emission in Chinese city.

Vehicle Emissions↗
PubMed2001

[UV photolysis mechanism of CCl4 and CHCl3 in water].

The photolysis mechanism of CCl4 and CHCl3 in water was studied by using transient absorption spectra. The results showed that aqueous CCl4 was dissociated into CCl3 and Cl radicals by 248 nm laser, and CHCl3 was dissociated into CHCl2 and Cl radicals after adding C6H6. The radicals CCl3 and CHCl2 were able to react with O2 to form CCl3O2 and CHCl2O2 respectively, or to form C2Cl6 and C2H2Cl4 without O2. The rate coefficients of some reactions were obtained.

Carbon Tetrachloride↗
PubMed2001

[Correction of nasal deformity in unilateral cleft lip of adult cases].

OBJECTIVE: Nasal deformities are very common in unilateral cleft lip cases. They are morphology of alar collapse, nasal floor depression and deviation of the septum. METHODS: Our operation procedure includes correction and replacement of the septum to the middle position, mobilization and suspension of the displaced alar cartilage and use of a "C" flap, nasal sill flap or a flap of the lip scar tissue to increase the length of columella on the cleft side. An implant or autograft of suitable size is placed, if necessary, in the nasal bridge or/and the nasal floor. RESULTS: Postoperative follow-up for 1-12 months showed that the results are satisfactory. CONCLUSIONS: Correction of septum deformity, and increase of the length of the columella on the cleft side are important. An extensive mobilization and reposition of the alar cartilage must be done for obtaining a symmetric nasal projection. If necessary, a fine implant or self-tissue is placed in the nasal bridge and nasal floor, which would make the result much better.

Adult↗
PubMed2001

[The significance of nucleotide repeat sequences in FVIII gene for detecting hemophilia A carriers].

OBJECTIVE: To detect the carriers in hemophilia A(HA) families by haplotype analysis of the microsatellite polymorphisms at intron 13 [13(CA)n] and 22[22(GT)n(AG)n] in the factor VIII (FVIII) gene. METHOD: Multi-PCR amplification of 13(CA)n and 22(GT)n(AG)n combined with silver staining were used. RESULTS: In 35 HA families, 11 had HA history. There were 21 female members in the 11 HA families and all of them were subjected to molecular study. Fourteen of the 21 females were confirmed to be carriers and approximately 72.7%(8 of 11) of these families were informative. CONCLUSIONS: Besides the reliable detection of HA carriers, multi-PCR combined with silver staining in HA analysis has the advantages of time saving, simplicity for performing and no radiation contamination.

Alleles↗
PubMed2001

Relationship between HLA-DRB1 and DQ alleles and the genetic susceptibility to type 1 diabetes.

OBJECTIVE: To study the relationship between human leukocyte antigen (HLA)-DRB1 and DQ alleles and the genetic susceptibility of type 1 diabetes in North Chinese children. METHODS: Polymerase chain reaction (PCR) techniques were used to amplify the second exon of DRB1 and DQ alleles, after which sequence specific olignucleotide probe (SSOP) dot blot hybridization techniques were used to analyze the amplified products. RESULTS: DRB1 * 0301, DQA1 * 0301, DQB1 * 0201 alleles and DRB1 * 0301-DQA1 * 0501-DQB1 * 0201 haplotype were significantly increased in patients, while DQA1 * 0103 and DQB1 * 0601 alleles were significantly increased in controls. The distribution of DR4 and DR9 haplotypes in patients and controls were not significantly different, but DR3/DR4 and DR4/DR9 heterozygotes were significantly increased in patients. CONCLUSIONS: DRB1 * 0301, DQA1 * 0301 and DQB1 * 0201 confer susceptibility while DQA1 * 0103 and DQB1 * 0601 confer protection to type 1 diabetes. DRB1 * 0301-DQA1 * 0501-DQB1 * 0201 haplotype offers a predisposition to type 1 diabetes in North Chinese. Although the distribution of DR4 and DR9 in patients and controls had no significant difference, DR3/DR4 and DR3/DR9 heterozygotes were significantly increased in patients, showing that the susceptive effects of DR3 and DR4 or DR4 and DR9 haplotypes could be added up.

Alleles↗
PubMed2001

Clinical significance of examining IL-2R in peripheral blood lymphocytes of patients with gastric cancer.

OBJECTIVE: To understand the clinical significance of membrane receptors of interleukin-2 (CD25) in peripheral blood lymphocytes (PBL) of patients with gastric cancer. METHODS: CD25 percentages in PBL from 110 patients with gastric cancer and 100 normal individuals were examined by flow cytometry. Results were analyzed clinically and pathologically. RESULTS: Mean CD25% in PBL from normal individuals and patients with gastric cancer were 17.24 +/- 5.33 and 22.47 +/- 6.82, respectively, and the difference was significant (P < 0.01). Abnormally elevated CD25% in PBL from patients with gastric cancer were correlated with tumor site, macropathology type, tumor size, differentiation degree and clinical stage. CONCLUSION: Measuring CD25% in PBL from gastric cancer patients before surgery may provide a reference for diagnosis, immune treatment and judging prognosis.

Adult↗
PubMed2001

[Application of positron emission tomography in diagnosis and treatment of lung cancer].

OBJECTIVE: To determine the usefulness of positron emission tomography(PET) with fluoro-2-deoxyglucose (FDG-PET) in lung cancer. METHODS: Patients who presented between September 1999 and March 2000 with lung cancer or indeterminate lung lesions on chest CT scan were enrolled and underwent FDG-PET scanning. RESULTS: Of the 88 patients, 68 (77.3%) patients had malignancy and 20(22.7%) patients had a benign lesion. Of the 125 lung lesions, 80(64.0%) malignant lesions had a median standard uptake ratio (SUR) of 2.8(range 0-12.0), while 45(36.0%) benign lesions had a median SUR of 0(range 0-3.7). There was significant difference between the two groups. The diagnostic sensitivity and specificity of PET imaging for lung lesions were associated with the size of lesions but not with radiation or chemotherapy given before. The diagnostic specificity and accuracy of PET for lung lesions were significantly higher than those of CT scan. The sensitivity, specificity and accuracy of SUR method were 65.0%, 91.1% and 74.4% respectively and those of PET visual analysis were 95.0%, 95.6% and 95.2% respectively. The accuracy for lung lesions > or = 1.5 cm with SUR method was higher than that of lesions < 1.5 cm, being 93.8% and 62.3% respectively. The diagnostic sensitivity and accuracy of PET visual analysis for lymph node metastasis were significantly higher than those of CT scan. SUR was not correlated with the degree of cell differentiation, but it decreased significantly in small cell lung cancer after radiation or chemotherapy. CONCLUSIONS: PET is of advantage to the evaluation of lung lesions and diagnosis of lymph node metastasis in lung cancer. PET visual analysis is recommended in lung lesions after radiation or chemotherapy or with size < 1.5 cm in diameter.

Adult↗
PubMed2001

[Mycobacterium tuberculosis L forms in patients with pulmonary silicotuberculosis and silicosis].

OBJECTIVE: To evaluate significance of Mycobacterium tuberculosis L forms in pathogenesis of silicotuberculosis and silicosis. METHODS: Sputum culture for Mycobacterium tuberculosis and its L forms was conducted from both silicotuberculosis and silicosis groups, and the results were compared. RESULTS: Among 60 silicotuberculosis patients, 6 (10%) were sputum Mycobacterium tuberculosis culture positive, of which 5 (83%) were Mycobacterium tuberculosis L forms culture positive; 28 were sputum Mycobacterium tuberculosis L forms culture positive (positive rates in the patients with silicosis stage I, stage II, stage III were 33%, 67%, 100% respectively), with a positive rate of 47%, and a significant difference was found comparing with the frequency of detecting Mycobacterium tuberculosis (P < 0.01). All of the 30 cases with silicosis were Mycobacterium tuberculosis culture negative, however, 3 of them were sputum Mycobacterium tuberculosis L forms culture positive, accounting for 10 percent. CONCLUSIONS: Sputum culture for Mycobacterium tuberculosis L forms is a convenient and rapid way to improve the detection rate of Mycobacterium tuberculosis, with a positive value in early diagnosis of silicotuberculosis by reducing misdiagnosis and underdiagnosis of this disease. Detection rate of Mycobacterium tuberculosis L forms significantly increases with deterioration of silicosis.

Aged↗
PubMed2001

Outcome of 2,284 cases with acute traumatic brain injury.

OBJECTIVE: To analyze the prognosis of 2284 cases with acute traumatic brain injury and discuss possible methods to improve the outcome of head injuries. METHODS: The relationship between trauma cause, trauma severity and management and patient's outcome was retrospectively analyzed. RESULTS: Good recovery was achieved in 60.20%, moderate disability was 13.22%, severe disability 15.24%, vegetative status 0.31% and mortality 11.03%. The mortality was 1.07% in cases with GCS 15-13, 2.47% in cases with GCS 12-9, 13.29% in cases with GCS 8-6, and 57.4% in cases with GCS 5-3. CONCLUSIONS: To prevent hypoxia, remove intracranial hematoma as soon as possible, use standard large traumatic craniotomy and apply mild hypothermia may be useful means for improving the outcome of severely head injured patients.

Acute Disease↗